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Foley AR, Bolduc V, Guirguis F, Donkervoort S, Hu Y, Orbach R, McCarty RM, Sarathy A, Norato G, Cummings BB, Lek M, Sarkozy A, Butterfield RJ, Kirschner J, Nascimento A, Benito DND, Quijano-Roy S, Stojkovic T, Merlini L, Comi G, Ryan M, McDonald D, Munot P, Yoon G, Leung E, Finanger E, Leach ME, Collins J, Tian C, Mohassel P, Neuhaus SB, Saade D, Cocanougher BT, Chu ML, Scavina M, Grosmann C, Richardson R, Kossak BD, Gospe SM, Bhise V, Taurina G, Lace B, Troncoso M, Shohat M, Shalata A, Chan SH, Jokela M, Palmio J, Haliloğlu G, Jou C, Gartioux C, Solomon-Degefa H, Freiburg CD, Schiavinato A, Zhou H, Aguti S, Nevo Y, Nishino I, Jimenez-Mallebrera C, Lamandé SR, Allamand V, Gualandi F, Ferlini A, MacArthur DG, Wilton SD, Wagener R, Bertini E, Muntoni F, Bönnemann CG. The recurrent deep intronic pseudoexon-inducing variant COL6A1 c.930+189C>T results in a consistently severe phenotype of COL6-related dystrophy: Towards clinical trial readiness for splice-modulating therapy. medRxiv 2024:2024.03.29.24304673. [PMID: 38585825 PMCID: PMC10996746 DOI: 10.1101/2024.03.29.24304673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Collagen VI-related dystrophies (COL6-RDs) manifest with a spectrum of clinical phenotypes, ranging from Ullrich congenital muscular dystrophy (UCMD), presenting with prominent congenital symptoms and characterised by progressive muscle weakness, joint contractures and respiratory insufficiency, to Bethlem muscular dystrophy, with milder symptoms typically recognised later and at times resembling a limb girdle muscular dystrophy, and intermediate phenotypes falling between UCMD and Bethlem muscular dystrophy. Despite clinical and immunohistochemical features highly suggestive of COL6-RD, some patients had remained without an identified causative variant in COL6A1, COL6A2 or COL6A3. With combined muscle RNA-sequencing and whole-genome sequencing we uncovered a recurrent, de novo deep intronic variant in intron 11 of COL6A1 (c.930+189C>T) that leads to a dominantly acting in-frame pseudoexon insertion. We subsequently identified and have characterised an international cohort of forty-four patients with this COL6A1 intron 11 causative variant, one of the most common recurrent causative variants in the collagen VI genes. Patients manifest a consistently severe phenotype characterised by a paucity of early symptoms followed by an accelerated progression to a severe form of UCMD, except for one patient with somatic mosaicism for this COL6A1 intron 11 variant who manifests a milder phenotype consistent with Bethlem muscular dystrophy. Characterisation of this individual provides a robust validation for the development of our pseudoexon skipping therapy. We have previously shown that splice-modulating antisense oligomers applied in vitro effectively decreased the abundance of the mutant pseudoexon-containing COL6A1 transcripts to levels comparable to the in vivo scenario of the somatic mosaicism shown here, indicating that this therapeutic approach carries significant translational promise for ameliorating the severe form of UCMD caused by this common recurrent COL6A1 causative variant to a Bethlem muscular dystrophy phenotype.
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Affiliation(s)
- A. Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Véronique Bolduc
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Fady Guirguis
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Ying Hu
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Rotem Orbach
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
- Dana-Dwek Children’s Hospital, Tel Aviv 64239, Israel
| | - Riley M. McCarty
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Apurva Sarathy
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Gina Norato
- Clinical Trials Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | | | - Monkol Lek
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Anna Sarkozy
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children, London WC1N 1EH, UK
| | - Russell J. Butterfield
- Departments of Neurology and Pediatrics, University of Utah, Salt Lake City, UT 84132, USA
| | - Janbernd Kirschner
- Department of Neuropediatrics and Muscle Disorders, Medical Center – University of Freiburg, Faculty of Medicine, Freiburg 79110, Germany
| | - Andrés Nascimento
- Neuromuscular Unit, Neuropediatrics Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu. CIBERER ISCIII. Barcelona 08950, Spain
| | - Daniel Natera-de Benito
- Neuromuscular Unit, Neuropediatrics Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu. CIBERER ISCIII. Barcelona 08950, Spain
| | - Susana Quijano-Roy
- Garches Neuromuscular Reference Center, Child Neurology and ICU Department, APHP Raymond Poincare University Hospital (UVSQ Paris Saclay), Garches 92380, France
| | - Tanya Stojkovic
- Centre de Référence des Maladies Neuromusculaires Nord/Est/Île-de-France, Institut de Myologie, Hôpital Pitié-Salpêtrière, AP-HP, Paris 75013, France
| | - Luciano Merlini
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna 40126, Italy
| | - Giacomo Comi
- Neurology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Monique Ryan
- Department of Neurology, The Royal Children’s Hospital, Parkville, VIC 3052, Australia
| | - Denise McDonald
- Department of Neurodisability, Children’s Health Ireland at Tallaght, Dublin 24 Ireland
| | - Pinki Munot
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children, London WC1N 1EH, UK
| | - Grace Yoon
- Department of Pediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Edward Leung
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB R3A 1S1, Canada
| | - Erika Finanger
- Department of Pediatrics and Neurology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Meganne E. Leach
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
- Department of Pediatrics and Neurology, Oregon Health & Science University, Portland, OR 97239, USA
| | - James Collins
- Divisions of Neurology and Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Cuixia Tian
- Divisions of Neurology and Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Payam Mohassel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Sarah B. Neuhaus
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Dimah Saade
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Benjamin T. Cocanougher
- Division of Medical Genetics, Department of Pediatrics, Duke University, Durham, NC 27710, USA
| | - Mary-Lynn Chu
- Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Mena Scavina
- Division of Neurology, Nemours Children’s Hospital Delaware, Wilmington, DE 19803, USA
| | - Carla Grosmann
- Department of Neurology, Rady Children’s Hospital University of California San Diego, San Diego, CA 92123, USA
| | - Randal Richardson
- Department of Neurology, Gillette Children’s Specialty Healthcare, St Paul, MN 55101, USA
| | - Brian D. Kossak
- Department of Neurology, Dartmouth Hitchcock Medical Center, Lebanon, NH 03766, USA
| | - Sidney M. Gospe
- Department of Neurology and Pediatrics, University of Washington, Seattle, WA 98105, USA
| | - Vikram Bhise
- Departments of Pediatrics and Neurology, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Gita Taurina
- Children’s Clinical University Hospital, Medical Genetics and Prenatal Diagnostic Clinic, Riga 1004, Latvia
| | - Baiba Lace
- Riga East Clinical University, Institute of Clinical and Preventive Medicine of the University of Latvia, Riga 1586, Latvia
| | - Monica Troncoso
- Pediatric Neuropsychiatry Service, Hospital Clínico San Borja Arriarán, Pediatric Department, Universidad de Chile, Santiago 1234, Chile
| | - Mordechai Shohat
- The Genomics Unit, Sheba Cancer Research Center, Sheba Medical Center, Ramat Gan 52621, Israel
| | - Adel Shalata
- The Simon Winter Institute for Human Genetics, Bnai Zion Medical Center, The Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Sophelia H.S. Chan
- Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Special Administrative Region, China
| | - Manu Jokela
- Clinical Neurosciences, University of Turku, Turku, Finland and Neurocenter, Turku University Hospital, Turku 20520, Finland
- Neuromuscular Research Center, Tampere University and Tampere University Hospital, Tampere 33101, Finland
| | - Johanna Palmio
- Neuromuscular Research Center, Tampere University and Tampere University Hospital, Tampere 33101, Finland
| | - Göknur Haliloğlu
- Division of Pediatric Neurology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara 06230, Turkey
| | - Cristina Jou
- Pathology department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Barcelona 08950, Spain
| | - Corine Gartioux
- INSERM, Institut de Myologie, Centre de Recherche en Myologie, Sorbonne Université, Paris 75013, France
| | | | - Carolin D. Freiburg
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne 50931, Germany
| | - Alvise Schiavinato
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne 50931, Germany
| | - Haiyan Zhou
- National Institute of Health Research, Great Ormond Street Hospital Biomedical Research Centre, Genetics and Genomic Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Sara Aguti
- Neurodegenerative Disease Department, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Yoram Nevo
- Institute of Pediatric Neurology, Schneider Children’s Medical Center of Israel, Petach Tikva, Israel, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan
| | - Cecilia Jimenez-Mallebrera
- Laboratorio de Investigación Aplicada en Enfermedades Neuromusculares, Unidad de Patología Neuromuscular, Servicio de Neuropediatría, Institut de Recerca Sant Joan de Déu, Barcelona 08950, Spain
| | - Shireen R. Lamandé
- Department of Paediatrics, University of Melbourne, The Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
| | - Valérie Allamand
- INSERM, Institut de Myologie, Centre de Recherche en Myologie, Sorbonne Université, Paris 75013, France
| | - Francesca Gualandi
- Unit of Medical Genetics, Department of Medical Sciences and Department of Mother and Child, University Hospital S. Anna Ferrara, Ferrara 44121, Italy
| | - Alessandra Ferlini
- Unit of Medical Genetics, Department of Medical Sciences and Department of Mother and Child, University Hospital S. Anna Ferrara, Ferrara 44121, Italy
| | | | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University; Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Raimund Wagener
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne 50931, Germany
| | - Enrico Bertini
- Research Unit of Neuromuscular and Neurodegenerative Disorders, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children, London WC1N 1EH, UK
- National Institute of Health Research, Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
| | - Carsten G. Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
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Cale JM, Ham KA, Li D, McIntosh CS, Watts GF, Wilton SD, Aung-Htut MT. Induced alternative splicing an opportunity to study PCSK9 protein isoforms at physiologically relevant concentrations. Sci Rep 2023; 13:19725. [PMID: 37957262 PMCID: PMC10643364 DOI: 10.1038/s41598-023-47005-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 11/07/2023] [Indexed: 11/15/2023] Open
Abstract
Splice modulating antisense oligomers (AOs) are increasingly used to modulate RNA processing. While most are investigated for their use as therapeutics, AOs can also be used for basic research. This study examined their use to investigate internally and terminally truncated proprotein convertase subtilisin/kexin type 9 (PCSK9) protein isoforms. Previous studies have used plasmid or viral-vector-mediated protein overexpression to study different PCSK9 protein isoforms, creating an artificial environment within the cell. Here we designed and tested AOs to remove specific exons that encode for PCSK9 protein domains and produced protein isoforms at more physiologically relevant levels. We evaluated the isoforms' expression, secretion, and subsequent impact on the low-density lipoprotein (LDL) receptor and its activity in Huh-7 cells. We found that modifying the Cis-His-rich domain by targeting exons 10 or 11 negatively affected LDL receptor activity and hence did not enhance LDL uptake although the levels of LDL receptor were increased. On the other hand, removing the hinge region encoded by exon 8, or a portion of the prodomain encoded by exon 2, have the potential as therapeutics for hypercholesterolemia. Our findings expand the understanding of PCSK9 isoforms and their impact on the LDL receptor and its activity at physiologically relevant concentrations.
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Affiliation(s)
- Jessica M Cale
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
| | - Kristin A Ham
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth, WA, 6009, Australia
| | - Dunhui Li
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth, WA, 6009, Australia
| | - Craig S McIntosh
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth, WA, 6009, Australia
| | - Gerald F Watts
- School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Perth, WA, 6009, Australia
- Cardiometabolic Clinic, Departments of Cardiology and Internal Medicine, Royal Perth Hospital, Perth, WA, 6000, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth, WA, 6009, Australia
| | - May T Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia.
- Perron Institute for Neurological and Translational Science, Perth, WA, 6009, Australia.
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Huang D, Thompson JA, Chen SC, Adams A, Pitout I, Lima A, Zhang D, Jeffery RCH, Attia MS, McLaren TL, Lamey TM, De Roach JN, McLenachan S, Aung-Htut MT, Fletcher S, Wilton SD, Chen FK. Characterising splicing defects of ABCA4 variants within exons 13-50 in patient-derived fibroblasts. Exp Eye Res 2022; 225:109276. [PMID: 36209838 DOI: 10.1016/j.exer.2022.109276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 09/12/2022] [Accepted: 09/28/2022] [Indexed: 12/29/2022]
Abstract
The ATP-binding cassette subfamily A member 4 gene (ABCA4)-associated retinopathy, Stargardt disease, is the most common monogenic inherited retinal disease. Given the pathogenicity of numerous ABCA4 variants is yet to be examined and a significant proportion (more than 15%) of ABCA4 variants are categorized as splice variants in silico, we therefore established a fibroblast-based splice assay to analyze ABCA4 variants in an Australian Stargardt disease cohort and characterize the pathogenic mechanisms of ABCA4 variants. A cohort of 67 patients clinically diagnosed with Stargardt disease was recruited. Genomic DNA was analysed using a commercial panel for ABCA4 variant detection and the consequences of ABCA4 variants were predicted in silico. Dermal fibroblasts were propagated from skin biopsies, total RNA was extracted and the ABCA4 transcript was amplified by RT-PCR. Our analysis identified a total of 67 unique alleles carrying 74 unique variants. The most prevalent splice-affecting complex allele c.[5461-10T>C; 5603A>T] was carried by 10% of patients in a compound heterozygous state. ABCA4 transcripts from exon 13 to exon 50 were readily detected in fibroblasts. In this region, aberrant splicing was evident in 10 out of 57 variant transcripts (18%), carried by 19 patients (28%). Patient-derived fibroblasts provide a feasible platform for identification of ABCA4 splice variants located within exons 13-50. Experimental evidence of aberrant splicing contributes to the pathogenic classification for ABCA4 variants. Moreover, identification of variants that affect splicing processes provides opportunities for intervention, in particular antisense oligonucleotide-mediated splice correction.
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Affiliation(s)
- Di Huang
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Shang-Chih Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Abbie Adams
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Ianthe Pitout
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Alanis Lima
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Dan Zhang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Rachael C Heath Jeffery
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Royal Victorian Eye and Ear Hospital, Centre for Eye Research Australia, East Melbourne, Victoria, Australia
| | - Mary S Attia
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Terri L McLaren
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Tina M Lamey
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - John N De Roach
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia; PYC Therapeutics, Harry Perkins Institute of Medical Research, Verdun St, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Fred K Chen
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia; Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia; Royal Victorian Eye and Ear Hospital, Centre for Eye Research Australia, East Melbourne, Victoria, Australia.
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4
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Ham KA, Johnsen RD, Tchan M, Wilton SD, Aung-Htut MT. Developing Therapeutic Splice-Correcting Antisense Oligomers for Adult-Onset Pompe Disease with c.-32-13T>G Mutation. Methods Mol Biol 2022; 2587:239-251. [PMID: 36401034 DOI: 10.1007/978-1-0716-2772-3_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The mutation c.-32-13T>G in the GAA gene impacts normal exon 2 splicing and is found in two-thirds of late-onset Pompe disease cases. We have explored a therapeutic strategy using splice modulating phosphorodiamidate morpholino oligomers to enhance GAA exon 2 inclusion in the mature mRNA of patients carrying this common mutation. We performed in silico analysis of the GAA gene transcript for potential splicing silencers and designed oligomers targeting motifs predicted to enhance exon 2 retention in the mature mRNA. Two patient-derived fibroblasts were obtained from Coriell Institute for Medical Research, and seven fibroblast strains from unrelated patients were supplied by Westmead Hospital in Sydney, Australia. Both fibroblasts and forced-myogenic cells were treated with optimized phosphorodiamidate morpholino oligomers supplied by Sarepta Therapeutics. Total RNA and protein were extracted from the cells after incubation with phosphorodiamidate morpholino oligomers, and RT-PCR and RT-qPCR were performed to confirm exon 2 inclusion is enhanced. Acid α-glucosidase activity and expression levels were also assessed to confirm therapeutic potential.
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Affiliation(s)
- Kristin A Ham
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Crawley, WA, Australia
| | - Russell D Johnsen
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Crawley, WA, Australia
| | - Michel Tchan
- Genetic Medicine, Westmead Hospital, Sydney, Australia.,Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Crawley, WA, Australia
| | - May T Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia. .,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia. .,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Crawley, WA, Australia.
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Li D, Mastaglia FL, Yau WY, Chen S, Wilton SD, Akkari PA. Targeted Molecular Therapeutics for Parkinson's Disease: A Role for Antisense Oligonucleotides? Mov Disord 2022; 37:2184-2190. [PMID: 36036206 PMCID: PMC9804368 DOI: 10.1002/mds.29201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/26/2022] [Accepted: 08/03/2022] [Indexed: 01/05/2023] Open
Affiliation(s)
- Dunhui Li
- Perron Institute for Neurological and Translational ScienceThe University of Western AustraliaNedlandsAustralia,Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochAustralia,College of Nursing and HealthZhengzhou UniversityZhengzhouChina
| | - Frank L. Mastaglia
- Perron Institute for Neurological and Translational ScienceThe University of Western AustraliaNedlandsAustralia,Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochAustralia
| | - Wai Yan Yau
- Perron Institute for Neurological and Translational ScienceThe University of Western AustraliaNedlandsAustralia
| | - Shengdi Chen
- Department of Neurology and Institute of NeurologyRuijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghaiChina
| | - Steve D. Wilton
- Perron Institute for Neurological and Translational ScienceThe University of Western AustraliaNedlandsAustralia,Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochAustralia
| | - Patrick A. Akkari
- Perron Institute for Neurological and Translational ScienceThe University of Western AustraliaNedlandsAustralia,Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochAustralia,Department of NeurologyDuke UniversityDurhamNorth CarolinaUSA
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Zaw K, Carvalho LS, Aung-Htut MT, Fletcher S, Wilton SD, Chen FK, McLenachan S. Pathogenesis and Treatment of Usher Syndrome Type IIA. Asia Pac J Ophthalmol (Phila) 2022; 11:369-379. [PMID: 36041150 DOI: 10.1097/apo.0000000000000546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/27/2022] [Indexed: 12/16/2022] Open
Abstract
Usher syndrome (USH) is the most common form of deaf-blindness, with an estimated prevalence of 4.4 to 16.6 per 100,000 people worldwide. The most common form of USH is type IIA (USH2A), which is caused by homozygous or compound heterozygous mutations in the USH2A gene and accounts for around half of all USH cases. USH2A patients show moderate to severe hearing loss from birth, with diagnosis of retinitis pigmentosa in the second decade of life and variable vestibular involvement. Although hearing aids or cochlear implants can provide some mitigation of hearing deficits, there are currently no treatments aimed at preventing or restoring vision loss in USH2A patients. In this review, we first provide an overview of the molecular biology of the USH2A gene and its protein isoforms, which include a transmembrane protein (TM usherin) and an extracellular protein (EC usherin). The role of these proteins in the inner ear and retina and their impact on the pathogenesis of USH2A is discussed. We review animal cell-derived and patient cell-derived models currently used in USH2A research and conclude with an overview of potential treatment strategies currently in preclinical development and clinical trials.
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Affiliation(s)
- Khine Zaw
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Livia S Carvalho
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
| | - May T Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
- Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Samuel McLenachan
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
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7
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Keegan NP, Wilton SD, Fletcher S. Corrigendum: Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 13:943044. [PMID: 35754842 PMCID: PMC9218974 DOI: 10.3389/fgene.2022.943044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 05/18/2022] [Indexed: 11/14/2022] Open
Affiliation(s)
- Niall P Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
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8
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Flynn LL, Li R, Pitout IL, Aung-Htut MT, Larcher LM, Cooper JAL, Greer KL, Hubbard A, Griffiths L, Bond CS, Wilton SD, Fox AH, Fletcher S. Single Stranded Fully Modified-Phosphorothioate Oligonucleotides can Induce Structured Nuclear Inclusions, Alter Nuclear Protein Localization and Disturb the Transcriptome In Vitro. Front Genet 2022; 13:791416. [PMID: 35464859 PMCID: PMC9019733 DOI: 10.3389/fgene.2022.791416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 03/02/2022] [Indexed: 01/12/2023] Open
Abstract
Oligonucleotides and nucleic acid analogues that alter gene expression are now showing therapeutic promise in human disease. Whilst the modification of synthetic nucleic acids to protect against nuclease degradation and to influence drug function is common practice, such modifications may also confer unexpected physicochemical and biological properties. Gapmer mixed-modified and DNA oligonucleotides on a phosphorothioate backbone can bind non-specifically to intracellular proteins to form a variety of toxic inclusions, driven by the phosphorothioate linkages, but also influenced by the oligonucleotide sequence. Recently, the non-antisense or other off-target effects of 2′ O- fully modified phosphorothioate linkage oligonucleotides are becoming better understood. Here, we report chemistry-specific effects of oligonucleotides composed of modified or unmodified bases, with phosphorothioate linkages, on subnuclear organelles and show altered distribution of nuclear proteins, the appearance of highly stable and strikingly structured nuclear inclusions, and disturbed RNA processing in primary human fibroblasts and other cultured cells. Phosphodiester, phosphorodiamidate morpholino oligomers, and annealed complimentary phosphorothioate oligomer duplexes elicited no such consequences. Disruption of subnuclear structures and proteins elicit severe phenotypic disturbances, revealed by transcriptomic analysis of transfected fibroblasts exhibiting such disruption. Our data add to the growing body of evidence of off-target effects of some phosphorothioate nucleic acid drugs in primary cells and suggest alternative approaches to mitigate these effects.
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Affiliation(s)
- Loren L Flynn
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia.,Black Swan Pharmaceuticals, Wake Forest, NC, United States
| | - Ruohan Li
- Cell and Tissue Therapies WA, Royal Perth Hospital, Perth, WA, Australia.,School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Ianthe L Pitout
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,PYC Therapeutics, Nedlands, WA, Australia
| | - May T Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Leon M Larcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia
| | - Jack A L Cooper
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Kane L Greer
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Alysia Hubbard
- Centre for Microscopy, Characterization and Analysis, The University of Western Australia, Nedlands, WA, Australia
| | - Lisa Griffiths
- Anatomical Pathology, Department of Health, Nedlands, WA, Australia
| | - Charles S Bond
- School of Molecular Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Archa H Fox
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia.,School of Molecular Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia.,PYC Therapeutics, Nedlands, WA, Australia
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9
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Martinovich KM, Kicic A, Stick SM, Johnsen RD, Fletcher S, Wilton SD. Investigating the Implications of CFTR Exon Skipping Using a Cftr Exon 9 Deleted Mouse Model. Front Pharmacol 2022; 13:868863. [PMID: 35392567 PMCID: PMC8981082 DOI: 10.3389/fphar.2022.868863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction: Severity and disease progression in people with Cystic Fibrosis (CF) is typically dependent on their genotype. One potential therapeutic strategy for people with specific mutations is exon skipping with antisense oligonucleotides (AO). CFTR exon 9 is an in-frame exon and hence the exclusion of this exon would excise only 31 amino acids but not alter the reading frame of the remaining mRNA. Splice mutations 1209 + 1 G > C and 1209 + 2 T > G were documented to cause CFTR exon 9 skipping and these variants were reported to manifest as a milder CF disease, therefore exon 9 skipping could be beneficial for people with class I mutations that affect exon 9 such as p.Trp401X. While the impact of exon 9 skipping on gene expression and cellular pathways can be studied in cells in vitro, trace amount of full-length normal or mutated material could confound the evaluation. To overcome this limitation, the impact of CFTR exon 9 skipping on disease phenotype and severity is more effectively evaluated in a small animal model. It was hypothesised that antisense oligonucleotide-mediated skipping this particular exon could result in a "mild mouse CF phenotype". Methods: Cftr exon 9 deleted mice were generated using homologous recombination. Survival of homozygous (Cftr Δ9/Δ9 ) and heterozygous (Cftr Δ9/+ ) mice was compared to that of other CF mouse models, and lung and intestinal organ histology examined for any pathologies. Primary airway epithelial cells (pAECs) were harvested from Cftr Δ9/Δ9 mice and cultured at the Air Liquid Interface for CFTR functional assessment using Ussing Chamber analysis. Results: A Cftr Δ9/Δ9 mouse model presented with intestinal obstructions, and at time of weaning (21 days). Cftr Δ9/Δ9 mice had a survival rate of 83% that dropped to 38% by day 50. Histological sections of the small intestine from Cftr Δ9/Δ9 mice showed more goblet cells and mucus accumulation than samples from the Cftr Δ9/+ littermates. Airway epithelial cell cultures established from Cftr Δ9/Δ9 mice were not responsive to forskolin stimulation. Summary: The effect of Cftr exon 9 deletion on Cftr function was assessed and it was determined that the encoded Cftr isoform did not result in a milder "mouse CF disease phenotype," suggesting that Cftr exon 9 is not dispensable, although further investigation in human CF pAECs would be required to confirm this observation.
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Affiliation(s)
- Kelly M Martinovich
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Telethon Kids Institute, Wal-yan Respiratory Research Centre, Perth, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia
| | - Anthony Kicic
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Telethon Kids Institute, Wal-yan Respiratory Research Centre, Perth, WA, Australia.,Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia, Perth, WA, Australia.,Department of Respiratory and Sleep Medicine, Perth Childrens Hospital, Nedlands, WA, Australia.,School of Population Health, Curtin University, Bentley, WA, Australia
| | - Stephen M Stick
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Telethon Kids Institute, Wal-yan Respiratory Research Centre, Perth, WA, Australia.,Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia, Perth, WA, Australia.,Department of Respiratory and Sleep Medicine, Perth Childrens Hospital, Nedlands, WA, Australia
| | - Russell D Johnsen
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute for Neurological and Translational Sciences, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute for Neurological and Translational Sciences, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia.,PYC Therapeutics, Perth, WA, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA, Australia.,Perron Institute for Neurological and Translational Sciences, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
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10
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Toosaranont J, Ruschadaariyachat S, Mujchariyakul W, Arora JK, Charoensawan V, Suktitipat B, Palmer TN, Fletcher S, Wilton SD, Mitrpant C. Antisense Oligonucleotide Induction of the hnRNPA1b Isoform Affects Pre-mRNA Splicing of SMN2 in SMA Type I Fibroblasts. Int J Mol Sci 2022; 23:ijms23073937. [PMID: 35409296 PMCID: PMC8999010 DOI: 10.3390/ijms23073937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/22/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe, debilitating neuromuscular condition characterised by loss of motor neurons and progressive muscle wasting. SMA is caused by a loss of expression of SMN1 that encodes the survival motor neuron (SMN) protein necessary for the survival of motor neurons. Restoration of SMN expression through increased inclusion of SMN2 exon 7 is known to ameliorate symptoms in SMA patients. As a consequence, regulation of pre-mRNA splicing of SMN2 could provide a potential molecular therapy for SMA. In this study, we explored if splice switching antisense oligonucleotides could redirect the splicing repressor hnRNPA1 to the hnRNPA1b isoform and restore SMN expression in fibroblasts from a type I SMA patient. Antisense oligonucleotides (AOs) were designed to promote exon 7b retention in the mature mRNA and induce the hnRNPA1b isoform. RT-PCR and western blot analysis were used to assess and monitor the efficiency of different AO combinations. A combination of AOs targeting multiple silencing motifs in hnRNPA1 pre-mRNA led to robust hnRNPA1b induction, which, in turn, significantly increased expression of full-length SMN (FL-SMN) protein. A combination of PMOs targeting the same motifs also strongly induced hnRNPA1b isoform, but surprisingly SMN2 exon 5 skipping was detected, and the PMO cocktail did not lead to a significant increase in expression of FL-SMN protein. We further performed RNA sequencing to assess the genome-wide effects of hnRNPA1b induction. Some 3244 genes were differentially expressed between the hnRNPA1b-induced and untreated SMA fibroblasts, which are functionally enriched in cell cycle and chromosome segregation processes. RT-PCR analysis demonstrated that expression of the master regulator of these enrichment pathways, MYBL2 and FOXM1B, were reduced in response to PMO treatment. These findings suggested that induction of hnRNPA1b can promote SMN protein expression, but not at sufficient levels to be clinically relevant.
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Affiliation(s)
- Jarichad Toosaranont
- Department of Biochemistry, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (J.T.); (S.R.); (B.S.)
| | - Sukanya Ruschadaariyachat
- Department of Biochemistry, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (J.T.); (S.R.); (B.S.)
| | - Warasinee Mujchariyakul
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10700, Thailand; (W.M.); (J.K.A.); (V.C.)
| | - Jantarika Kumar Arora
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10700, Thailand; (W.M.); (J.K.A.); (V.C.)
| | - Varodom Charoensawan
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10700, Thailand; (W.M.); (J.K.A.); (V.C.)
- Integrative Computational BioScience (ICBS) Center, Mahidol University, Nakhon Pathom 73170, Thailand
- Systems Biology of Diseases Research Unit, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Bhoom Suktitipat
- Department of Biochemistry, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (J.T.); (S.R.); (B.S.)
- Integrative Computational BioScience (ICBS) Center, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Thomas N. Palmer
- Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA 6009, Australia; (T.N.P.); (S.F.); (S.D.W.)
| | - Sue Fletcher
- Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA 6009, Australia; (T.N.P.); (S.F.); (S.D.W.)
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA 6150, Australia
| | - Steve D. Wilton
- Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA 6009, Australia; (T.N.P.); (S.F.); (S.D.W.)
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA 6150, Australia
| | - Chalermchai Mitrpant
- Department of Biochemistry, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (J.T.); (S.R.); (B.S.)
- Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA 6009, Australia; (T.N.P.); (S.F.); (S.D.W.)
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA 6150, Australia
- Correspondence:
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11
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Keegan NP, Wilton SD, Fletcher S. Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 12:806946. [PMID: 35140743 PMCID: PMC8819188 DOI: 10.3389/fgene.2021.806946] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/09/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding pre-mRNA splicing is crucial to accurately diagnosing and treating genetic diseases. However, mutations that alter splicing can exert highly diverse effects. Of all the known types of splicing mutations, perhaps the rarest and most difficult to predict are those that activate pseudoexons, sometimes also called cryptic exons. Unlike other splicing mutations that either destroy or redirect existing splice events, pseudoexon mutations appear to create entirely new exons within introns. Since exon definition in vertebrates requires coordinated arrangements of numerous RNA motifs, one might expect that pseudoexons would only arise when rearrangements of intronic DNA create novel exons by chance. Surprisingly, although such mutations do occur, a far more common cause of pseudoexons is deep-intronic single nucleotide variants, raising the question of why these latent exon-like tracts near the mutation sites have not already been purged from the genome by the evolutionary advantage of more efficient splicing. Possible answers may lie in deep intronic splicing processes such as recursive splicing or poison exon splicing. Because these processes utilize intronic motifs that benignly engage with the spliceosome, the regions involved may be more susceptible to exonization than other intronic regions would be. We speculated that a comprehensive study of reported pseudoexons might detect alignments with known deep intronic splice sites and could also permit the characterisation of novel pseudoexon categories. In this report, we present and analyse a catalogue of over 400 published pseudoexon splice events. In addition to confirming prior observations of the most common pseudoexon mutation types, the size of this catalogue also enabled us to suggest new categories for some of the rarer types of pseudoexon mutation. By comparing our catalogue against published datasets of non-canonical splice events, we also found that 15.7% of pseudoexons exhibit some splicing activity at one or both of their splice sites in non-mutant cells. Importantly, this included seven examples of experimentally confirmed recursive splice sites, confirming for the first time a long-suspected link between these two splicing phenomena. These findings have the potential to improve the fidelity of genetic diagnostics and reveal new targets for splice-modulating therapies.
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Affiliation(s)
- Niall P. Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
- *Correspondence: Niall P. Keegan,
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
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12
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Abstract
PURPOSE OF REVIEW Antisense oligomers (ASOs) have been available for decades: however, only recently have these molecules been applied clinically. This review aims to discuss the possible development of antisense-mediated splice correction therapies as precision medicines for familial hypercholesterolemic patients carrying mutations that compromise normal splicing of the low-density lipoprotein receptor (LDLR) gene transcript. RECENT FINDINGS Three antisense drugs are currently being assessed in ongoing clinical trials for dyslipidemias, aiming to lower the plasma concentrations of lipoproteins that lead to end-organ damage, principally coronary artery disease. Although a handful of drugs may be applicable to many patients with familial hypercholesterolemia (FH), mutation-specific personalised antisense drugs may be even more effective in selected patients. Currently, there is no therapy that effectively addresses mutations in the LDLR, the major cause of FH. Many mutations in the LDLR that disrupt normal pre-mRNA processing could be applicable to splice correction therapy to restore receptor activity. SUMMARY Precision medicine could provide long-term economic and social benefits if they can be implemented effectively and sustainably. Many mutations found in the LDLR gene could be amendable to therapeutic splice correction and we should consider developing a therapeutic ASO platform for these mutations.
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Affiliation(s)
- Craig S. McIntosh
- Perron Institute for Neurological and Translational Science, Nedlands, Western Australia, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
| | - Gerald F. Watts
- School of Medicine, University of Western Australia
- Lipid Disorders Clinic, Department of Cardiology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Steve D. Wilton
- Perron Institute for Neurological and Translational Science, Nedlands, Western Australia, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
| | - May T. Aung-Htut
- Perron Institute for Neurological and Translational Science, Nedlands, Western Australia, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
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13
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McIntosh CS, Li D, Wilton SD, Aung-Htut MT. Polyglutamine Ataxias: Our Current Molecular Understanding and What the Future Holds for Antisense Therapies. Biomedicines 2021; 9:1499. [PMID: 34829728 PMCID: PMC8615177 DOI: 10.3390/biomedicines9111499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 02/07/2023] Open
Abstract
Polyglutamine (polyQ) ataxias are a heterogenous group of neurological disorders all caused by an expanded CAG trinucleotide repeat located in the coding region of each unique causative gene. To date, polyQ ataxias encompass six disorders: spinocerebellar ataxia types 1, 2, 3, 6, 7, and 17 and account for a larger group of disorders simply known as polyglutamine disorders, which also includes Huntington's disease. These diseases are typically characterised by progressive ataxia, speech and swallowing difficulties, lack of coordination and gait, and are unfortunately fatal in nature, with the exception of SCA6. All the polyQ spinocerebellar ataxias have a hallmark feature of neuronal aggregations and share many common pathogenic mechanisms, such as mitochondrial dysfunction, impaired proteasomal function, and autophagy impairment. Currently, therapeutic options are limited, with no available treatments that slow or halt disease progression. Here, we discuss the common molecular and clinical presentations of polyQ spinocerebellar ataxias. We will also discuss the promising antisense oligonucleotide therapeutics being developed as treatments for these devastating diseases. With recent advancements and therapeutic approvals of various antisense therapies, it is envisioned that some of the studies reviewed may progress into clinical trials and beyond.
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Affiliation(s)
- Craig S. McIntosh
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute Murdoch University, Discovery Way, Murdoch, WA 6150, Australia; (C.S.M.); (D.L.); (S.D.W.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Dunhui Li
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute Murdoch University, Discovery Way, Murdoch, WA 6150, Australia; (C.S.M.); (D.L.); (S.D.W.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Steve D. Wilton
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute Murdoch University, Discovery Way, Murdoch, WA 6150, Australia; (C.S.M.); (D.L.); (S.D.W.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA 6009, Australia
| | - May T. Aung-Htut
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute Murdoch University, Discovery Way, Murdoch, WA 6150, Australia; (C.S.M.); (D.L.); (S.D.W.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA 6009, Australia
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14
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Abstract
Background: Stargardt disease (STGD1) is an autosomal recessive retinal dystrophy due to mutations in ABCA4, characterized by subretinal deposition of lipofuscin-like substances and bilateral centrifugal vision loss. Despite the tremendous progress made in the understanding of STGD1, there are no approved treatments to date. This review examines the challenges in the development of an effective STGD1 therapy.Materials and Methods: A literature review was performed through to June 2021 summarizing the spectrum of retinal phenotypes in STGD1, the molecular biology of ABCA4 protein, the in vivo and in vitro models used to investigate the mechanisms of ABCA4 mutations and current clinical trials.Results: STGD1 phenotypic variability remains an challenge for clinical trial design and patient selection. Pre-clinical development of therapeutic options has been limited by the lack of animal models reflecting the diverse phenotypic spectrum of STDG1. Patient-derived cell lines have facilitated the characterization of splice mutations but the clinical presentation is not always predicted by the effect of specific mutations on retinoid metabolism in cellular models. Current therapies primarily aim to delay vision loss whilst strategies to restore vision are less well developed.Conclusions: STGD1 therapy development can be accelerated by a deeper understanding of genotype-phenotype correlations.
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Affiliation(s)
- Di Huang
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia.,Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
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15
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Ham KA, Keegan NP, McIntosh CS, Aung-Htut MT, Zaw K, Greer K, Fletcher S, Wilton SD. Induction of cryptic pre-mRNA splice-switching by antisense oligonucleotides. Sci Rep 2021; 11:15137. [PMID: 34302060 PMCID: PMC8302632 DOI: 10.1038/s41598-021-94639-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 07/14/2021] [Indexed: 11/09/2022] Open
Abstract
Antisense oligomers (AOs) are increasingly being used to modulate RNA splicing in live cells, both for research and for the development of therapeutics. While the most common intended effect of these AOs is to induce skipping of whole exons, rare examples are emerging of AOs that induce skipping of only part of an exon, through activation of an internal cryptic splice site. In this report, we examined seven AO-induced cryptic splice sites in six genes. Five of these cryptic splice sites were discovered through our own experiments, and two originated from other published reports. We modelled the predicted effects of AO binding on the secondary structure of each of the RNA targets, and how these alterations would in turn affect the accessibility of the RNA to splice factors. We observed that a common predicted effect of AO binding was disruption of the exon definition signal within the exon's excluded segment.
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Affiliation(s)
- Kristin A Ham
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia
| | - Niall P Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia
| | - Craig S McIntosh
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia
| | - May T Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia
| | - Khine Zaw
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia.,Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Kane Greer
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, 6150, Australia. .,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, 6009, Australia.
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16
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Huang D, Zhang D, Chen SC, Thandar Aung-Htut M, Lamey TM, Thompson JA, McLaren TL, De Roach JN, Fletcher S, Wilton SD, McLenachan S, Chen FK. Generation of an induced pluripotent stem cell line from a patient with Stargardt disease caused by biallelic c.[5461-10T>C;5603A>T];[6077T>C] mutations in the ABCA4 gene. Stem Cell Res 2021; 54:102439. [PMID: 34214897 DOI: 10.1016/j.scr.2021.102439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 06/20/2021] [Indexed: 10/21/2022] Open
Abstract
Mutations in ABCA4 gene are causative for autosomal recessive Stargardt disease (STGD1), the most common inherited retinal dystrophy. Here, we report the generation of an induced pluripotent stem cell (iPSC) line from a STGD1 patient carrying biallelic c.[5461-10T>C;5603A>T];[6077T>C] mutations in the ABCA4 gene. Episomes carrying OCT4, SOX2, KLF4, L-MYC, LIN28 and mp53DD were employed for the reprogramming of patient-derived fibroblasts. This iPSC line expressed comparable pluripotency markers as in a commercially available human iPSC line, displayed normal karyotype and potential for trilineage differentiation, and were negative for both reprogramming episomes and mycoplasma test.
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Affiliation(s)
- Di Huang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Dan Zhang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Shang-Chih Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western, Australia
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Terri L McLaren
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western, Australia
| | - Samuel McLenachan
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
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17
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Huang D, Zhang D, Chen SC, Aung-Htut MT, Lamey TM, Thompson JA, McLaren TL, De Roach JN, Fletcher S, Wilton SD, Chen FK, McLenachan S. Generation of two induced pluripotent stem cell lines from a patient with Stargardt disease caused by compound heterozygous mutations in the ABCA4 gene. Stem Cell Res 2021; 54:102448. [PMID: 34198153 DOI: 10.1016/j.scr.2021.102448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022] Open
Abstract
Stargardt disease (STGD1) is the most common inherited retinal dystrophy and ABCA4 c.546--10 T>C is the most commonly reported splice mutation. Here, we generated and characterized two induced pluripotent stem cell (iPSC) lines from a STGD1 patient with compound heterozygous mutations in ABCA4 (c.[5461-10 T > C;5603A > T];[4163 T > C;455G > A]). Episomal vectors containing OCT4, SOX2, KLF4, L-MYC, LIN28 and mp53DD were employed to conduct the reprogramming of patient-derived fibroblasts. Both lines had a normal karyotype, displayed iPSC morphology, expressed pluripotency markers and showed trilineage differentiation potential. These lines can provide a powerful platform for further investigating the pathophysiological consequences of mutations in ABCA4.
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Affiliation(s)
- Di Huang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Dan Zhang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Shang-Chih Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Terri L McLaren
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Fred K Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia.
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18
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Flynn LL, Mitrpant C, Adams A, Pitout IL, Stirnweiss A, Fletcher S, Wilton SD. Targeted SMN Exon Skipping: A Useful Control to Assess In Vitro and In Vivo Splice-Switching Studies. Biomedicines 2021; 9:552. [PMID: 34069072 PMCID: PMC8156830 DOI: 10.3390/biomedicines9050552] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/11/2021] [Accepted: 05/11/2021] [Indexed: 01/23/2023] Open
Abstract
The literature surrounding the use of antisense oligonucleotides continues to grow, with new disease and mechanistic applications constantly evolving. Furthermore, the discovery and advancement of novel chemistries continues to improve antisense delivery, stability and effectiveness. For each new application, a rational sequence design is recommended for each oligomer, as is chemistry and delivery optimization. To confirm oligomer delivery and antisense activity, a positive control AO sequence with well characterized target-specific effects is recommended. Here, we describe splice-switching antisense oligomer sequences targeting the ubiquitously expressed human and mouse SMN and Smn genes for use as control AOs for this purpose. We report two AO sequences that induce targeted skipping of SMN1/SMN2 exon 7 and two sequences targeting the Smn gene, that induce skipping of exon 5 and exon 7. These antisense sequences proved effective in inducing alternative splicing in both in vitro and in vivo models and are therefore broadly applicable as controls. Not surprisingly, we discovered a number of differences in efficiency of exon removal between the two species, further highlighting the differences in splice regulation between species.
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Affiliation(s)
- Loren L. Flynn
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
- Black Swan Pharmaceuticals, Wake Forest, NC 27587, USA
| | - Chalermchai Mitrpant
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Abbie Adams
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
| | - Ianthe L. Pitout
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- PYC Therapeutics, Nedlands, WA 6009, Australia;
| | | | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
- PYC Therapeutics, Nedlands, WA 6009, Australia;
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
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19
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Cale JM, Greer K, Fletcher S, Wilton SD. Proof-of-Concept: Antisense Oligonucleotide Mediated Skipping of Fibrillin-1 Exon 52. Int J Mol Sci 2021; 22:ijms22073479. [PMID: 33801742 PMCID: PMC8037683 DOI: 10.3390/ijms22073479] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/16/2022] Open
Abstract
Marfan syndrome is one of the most common dominantly inherited connective tissue disorders, affecting 2–3 in 10,000 individuals, and is caused by one of over 2800 unique FBN1 mutations. Mutations in FBN1 result in reduced fibrillin-1 expression, or the production of two different fibrillin-1 monomers unable to interact to form functional microfibrils. Here, we describe in vitro evaluation of antisense oligonucleotides designed to mediate exclusion of FBN1 exon 52 during pre-mRNA splicing to restore monomer homology. Antisense oligonucleotide sequences were screened in healthy control fibroblasts. The most effective sequence was synthesised as a phosphorodiamidate morpholino oligomer, a chemistry shown to be safe and effective clinically. We show that exon 52 can be excluded in up to 100% of FBN1 transcripts in healthy control fibroblasts transfected with PMO52. Immunofluorescent staining revealed the loss of fibrillin 1 fibres with ~50% skipping and the subsequent re-appearance of fibres with >80% skipping. However, the effect of exon skipping on the function of the induced fibrillin-1 isoform remains to be explored. Therefore, these findings demonstrate proof-of-concept that exclusion of an exon from FBN1 pre-mRNA can result in internally truncated but identical monomers capable of forming fibres and lay a foundation for further investigation to determine the effect of exon skipping on fibrillin-1 function.
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Affiliation(s)
- Jessica M. Cale
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
| | - Kane Greer
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Nedlands, WA 6009, Australia
- PYC Therapeutics, Nedlands, WA 6009, Australia
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (J.M.C.); (K.G.); (S.F.)
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Nedlands, WA 6009, Australia
- Correspondence: ; Tel.: +61-8-9360-2305
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20
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Theunissen F, Anderton RS, Mastaglia FL, Flynn LL, Winter SJ, James I, Bedlack R, Hodgetts S, Fletcher S, Wilton SD, Laing NG, MacShane M, Needham M, Saunders A, Mackay-Sim A, Melamed Z, Ravits J, Cleveland DW, Akkari PA. Novel STMN2 Variant Linked to Amyotrophic Lateral Sclerosis Risk and Clinical Phenotype. Front Aging Neurosci 2021; 13:658226. [PMID: 33841129 PMCID: PMC8033025 DOI: 10.3389/fnagi.2021.658226] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/02/2021] [Indexed: 12/19/2022] Open
Abstract
Objective There is a critical need to establish genetic markers that explain the complex phenotypes and pathogenicity of ALS. This study identified a polymorphism in the Stathmin-2 gene and investigated its association with sporadic ALS (sALS) disease risk, age-of onset and survival duration. Methods The candidate CA repeat was systematically analyzed using PCR, Sanger sequencing and high throughput capillary separation for genotyping. Stathmin-2 expression was investigated using RT-PCR in patient olfactory neurosphere-derived (ONS) cells and RNA sequencing in laser-captured spinal motor neurons. Results In a case-control analysis of a combined North American sALS cohort (n = 321) and population control group (n = 332), long/long CA genotypes were significantly associated with disease risk (p = 0.042), and most strongly when one allele was a 24 CA repeat (p = 0.0023). In addition, longer CA allele length was associated with earlier age-of-onset (p = 0.039), and shorter survival duration in bulbar-onset cases (p = 0.006). In an Australian longitudinal sALS cohort (n = 67), ALS functional rating scale scores were significantly lower in carriers of the long/long genotype (p = 0.034). Stathmin-2 mRNA expression was reduced in sporadic patient ONS cells. Additionally, sALS patients and controls exhibited variable expression of Stathmin-2 mRNA according to CA genotype in laser-captured spinal motor neurons. Conclusions We report a novel non-coding CA repeat in Stathmin-2 which is associated with sALS disease risk and has disease modifying effects. The potential value of this variant as a disease marker and tool for cohort enrichment in clinical trials warrants further investigation.
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Affiliation(s)
- Frances Theunissen
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Ryan S Anderton
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,School of Health Sciences, Institute for Health Research, The University of Notre Dame Australia, Fremantle, WA, Australia
| | - Frank L Mastaglia
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia
| | - Loren L Flynn
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia
| | - Samantha J Winter
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,School of Health Sciences, Institute for Health Research, The University of Notre Dame Australia, Fremantle, WA, Australia
| | - Ian James
- Institute for Immunology and Infectious Disease, Murdoch University, Perth, WA, Australia
| | - Richard Bedlack
- Department of Neurology, Duke University, Durham, NC, United States
| | - Stuart Hodgetts
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,School of Human Sciences, University of Western Australia, Nedlands, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia
| | - Steve D Wilton
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia
| | - Nigel G Laing
- Centre for Medical Research, Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Mandi MacShane
- Centre for Medical Research, Harry Perkins Institute of Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Merrilee Needham
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Faculty of Medicine, The University of Notre Dame Australia, Fremantle, WA, Australia.,Department of Neurology, Fiona Stanley Hospital, Murdoch, WA, Australia
| | - Ann Saunders
- Zinfandel Pharmaceuticals, Chapel Hill, NC, United States
| | - Alan Mackay-Sim
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Ze'ev Melamed
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, United States
| | - John Ravits
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - P Anthony Akkari
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,Department of Neurology, Duke University, Durham, NC, United States
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21
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Zaw K, Wong EYM, Zhang X, Zhang D, Chen SC, Thompson JA, Lamey T, McLaren T, De Roach JN, Wilton SD, Fletcher S, Mitrpant C, Atlas MD, Chen FK, McLenachan S. Generation of three induced pluripotent stem cell lines from a patient with Usher syndrome caused by biallelic c.949C > A and c.1256G > T mutations in the USH2A gene. Stem Cell Res 2020; 50:102129. [PMID: 33360097 DOI: 10.1016/j.scr.2020.102129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/13/2020] [Indexed: 11/25/2022] Open
Abstract
Mutations in the USH2A gene are the most common cause of Usher syndrome and autosomal recessive non-syndromic retinitis pigmentosa. Here, we describe the generation of three induced pluripotent stem cell lines from dermal fibroblasts derived from a patient carrying biallelic c.949C > A and c.1256G > T variants in the USH2A gene, using episomal reprogramming plasmids expressing OCT4, SOX2, KLF4, MYCL, LIN28, mir302/367 and shRNA targeting TP53. All three lines expressed pluripotency markers, displayed unaltered karyotypes as well as trilineage differentiation potential, and were negative for reprogramming episomes and mycoplasma.
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Affiliation(s)
- Khine Zaw
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia; Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Elaine Y M Wong
- Ear Science Institute Australia, Nedlands, Western Australia, Australia; School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, Western Australia, Australia; Ear Sciences Centre, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Xiao Zhang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Dan Zhang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Shang-Chih Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Tina Lamey
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Terri McLaren
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia; Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia; Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia
| | - Chalermchai Mitrpant
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand; Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia
| | - Marcus D Atlas
- Ear Science Institute Australia, Nedlands, Western Australia, Australia; Ear Sciences Centre, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia; Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia.
| | - Samuel McLenachan
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia.
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22
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Ham KA, Aung-Htut MT, Fletcher S, Wilton SD. Nonsequential Splicing Events Alter Antisense-Mediated Exon Skipping Outcome in COL7A1. Int J Mol Sci 2020; 21:ijms21207705. [PMID: 33081018 PMCID: PMC7590164 DOI: 10.3390/ijms21207705] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/06/2020] [Accepted: 10/14/2020] [Indexed: 11/16/2022] Open
Abstract
The COL7A1 gene encodes homotrimer fibrils essential for anchoring dermal and epidermal layers, and pathogenic mutations in COL7A1 can cause recessive or dominant dystrophic epidermolysis bullosa. As a monogenic disease gene, COL7A1 constitutes a potential target for antisense oligomer-mediated exon skipping, a therapy applicable to a growing number of other genetic disorders. However, certain characteristics of COL7A1: many exons, low average intron size, and repetitive and guanine-cytosine rich coding sequence, present challenges to the design of specific and effective antisense oligomers. While targeting COL7A1 exons 10 and 73 for excision from the mature mRNA, we discovered that antisense oligomers comprised of 2′-O-methyl modified bases on a phosphorothioate backbone and phosphorodiamidate morpholino oligomers produced similar, but distinctive, splicing patterns including excision of adjacent nontargeted exons and/or retention of nearby introns in some transcripts. We found that the nonsequential splicing of certain introns may alter pre-mRNA processing during antisense oligomer-mediated exon skipping and, therefore, additional studies are required to determine if the order of intron removal influences multiexon skipping and/or intron retention in processing of the COL7A1 pre-mRNA.
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Affiliation(s)
- Kristin A. Ham
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch 6150, Australia; (K.A.H.); (M.T.A.-H.); (S.F.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands 6009, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch 6150, Australia; (K.A.H.); (M.T.A.-H.); (S.F.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands 6009, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch 6150, Australia; (K.A.H.); (M.T.A.-H.); (S.F.)
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch 6150, Australia; (K.A.H.); (M.T.A.-H.); (S.F.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands 6009, Australia
- Correspondence:
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23
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Roshandel D, Thompson JA, Charng J, Zhang D, Chelva E, Arunachalam S, Attia MS, Lamey TM, McLaren TL, De Roach JN, Mackey DA, Wilton SD, Fletcher S, McLenachan S, Chen FK. Exploring microperimetry and autofluorescence endpoints for monitoring disease progression in PRPF31-associated retinopathy. Ophthalmic Genet 2020; 42:1-14. [PMID: 32985313 DOI: 10.1080/13816810.2020.1827442] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND Mutations in the splicing factor pre-messenger RNA processing factor 31 (PRPF31) gene cause autosomal dominant retinitis pigmentosa 11 (RP11) through a haplo-insufficiency mechanism. We describe the phenotype and progression of microperimetry and autofluorescence endpoints in an Indigenous Australian RP11 family. PATIENTS AND METHODS Ophthalmic examination, optical coherence tomography, fundus autofluorescence and microperimetry were performed at baseline and every 6-12 months. Baseline and annual change in best-corrected visual acuity (BCVA), microperimetry mean sensitivity (MS) and number of scotoma loci, residual ellipsoid zone (EZ) span and hyperautofluorescent ring (HAR) area were reported. Next-generation and Sanger sequencing were performed in available members. RESULTS 12 affected members from three generations were examined. Mean (SD, range) age at onset of symptoms was 11 (4.5, 4-19) years. MS declined steadily from the third decade and EZ span and HAR area declined rapidly during the second decade. Serial microperimetry showed negligible change in MS over 2-3 years. However, mean EZ span, near-infrared and short-wavelength HAR area reduction was 203 (6.4%) µm/year, 1.8 (8.7%) mm2/year and 1.1 (8.6%) mm2/year, respectively. Genetic testing was performed on 11 affected and 10 asymptomatic members and PRPF31 c.1205 C > A (p.Ser402Ter) mutation was detected in all affected and two asymptomatic members (non-penetrant carriers). CONCLUSIONS Our findings suggest that in the studied cohort, the optimal window for therapeutic intervention is the second decade of life and residual EZ span and HAR area can be considered as efficacy outcome measures. Further studies on larger samples with different PRPF31 mutations and longer follow-up duration are recommended.
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Affiliation(s)
- Danial Roshandel
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital , Nedlands, Australia
| | - Jason Charng
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia
| | - Dan Zhang
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia
| | - Enid Chelva
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital , Nedlands, Australia
| | - Sukanya Arunachalam
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia
| | - Mary S Attia
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital , Nedlands, Australia
| | - Terri L McLaren
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital , Nedlands, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital , Nedlands, Australia
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital , Nedlands, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University , Murdoch, Australia.,The Perron Institute, The University of Western Australia , Nedlands, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University , Murdoch, Australia.,The Perron Institute, The University of Western Australia , Nedlands, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science, The University of Western Australia , Perth, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute , Nedlands, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital , Nedlands, Australia.,Department of Ophthalmology, Royal Perth Hospital , Perth, Australia.,Department of Ophthalmology, Perth Children's Hospital , Nedlands, Australia
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24
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Li D, Mastaglia FL, Fletcher S, Wilton SD. Progress in the molecular pathogenesis and nucleic acid therapeutics for Parkinson's disease in the precision medicine era. Med Res Rev 2020; 40:2650-2681. [PMID: 32767426 PMCID: PMC7589267 DOI: 10.1002/med.21718] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 07/02/2020] [Accepted: 07/25/2020] [Indexed: 12/16/2022]
Abstract
Parkinson's disease (PD) is one of the most common neurodegenerative disorders that manifest various motor and nonmotor symptoms. Although currently available therapies can alleviate some of the symptoms, the disease continues to progress, leading eventually to severe motor and cognitive decline and reduced life expectancy. The past two decades have witnessed rapid progress in our understanding of the molecular and genetic pathogenesis of the disease, paving the way for the development of new therapeutic approaches to arrest or delay the neurodegenerative process. As a result of these advances, biomarker‐driven subtyping is making it possible to stratify PD patients into more homogeneous subgroups that may better respond to potential genetic‐molecular pathway targeted disease‐modifying therapies. Therapeutic nucleic acid oligomers can bind to target gene sequences with very high specificity in a base‐pairing manner and precisely modulate downstream molecular events. Recently, nucleic acid therapeutics have proven effective in the treatment of a number of severe neurological and neuromuscular disorders, drawing increasing attention to the possibility of developing novel molecular therapies for PD. In this review, we update the molecular pathogenesis of PD and discuss progress in the use of antisense oligonucleotides, small interfering RNAs, short hairpin RNAs, aptamers, and microRNA‐based therapeutics to target critical elements in the pathogenesis of PD that could have the potential to modify disease progression. In addition, recent advances in the delivery of nucleic acid compounds across the blood–brain barrier and challenges facing PD clinical trials are also reviewed.
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Affiliation(s)
- Dunhui Li
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Frank L Mastaglia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
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25
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Huang D, Thompson JA, Charng J, Chelva E, McLenachan S, Chen S, Zhang D, McLaren TL, Lamey TM, Constable IJ, De Roach JN, Aung‐Htut MT, Adams A, Fletcher S, Wilton SD, Chen FK. Phenotype-genotype correlations in a pseudodominant Stargardt disease pedigree due to a novel ABCA4 deletion-insertion variant causing a splicing defect. Mol Genet Genomic Med 2020; 8:e1259. [PMID: 32627976 PMCID: PMC7336727 DOI: 10.1002/mgg3.1259] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Deletion-insertion (delins) variants in the retina-specific ATP-binding cassette transporter gene, subfamily A, member 4 (ABCA4) accounts for <1% in Stargardt disease. The consequences of these delins variants on splicing cannot be predicted with certainty without supporting in vitro data. METHODS Candidate ABCA4 variants were revealed by genetic and segregation analysis of a family with pseudodominant Stargardt disease using a commercial panel and Sanger sequencing. RNA extracted from patient-derived fibroblasts was analyzed by RT-PCR to evaluate splicing behavior of the ABCA4 variants. RESULTS Affected members carrying the novel c.6031_6044delinsAGTATTTAACCAATATTT variant in exon 44 presented with contrasting phenotypes; from early-onset cone-rod dystrophy to late-onset macular dystrophy. This variant resulted in a 56-nucleotide deletion in the mutant allele by activation of a cryptic splice acceptor site which disrupts the reading frame and results in a premature termination codon (p.Ile2003LeufsTer41). If translated, the crucial functional domains near the C-terminus would be truncated from the ABCA4 protein. CONCLUSION This work demonstrates the intrafamilial phenotypic variability in a pseudodominant Stargardt disease pedigree and the use of patient-derived fibroblasts to evaluate the effect of a novel ABCA4 delins variant on splicing to complement in silico pathogenicity assessment.
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Affiliation(s)
- Di Huang
- Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochWestern AustraliaAustralia
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
- Centre for Neuromuscular and Neurological DisordersThe University of Western Australia and Perron Institute for Neurological and Translational ScienceNedlandsWestern AustraliaAustralia
| | - Jennifer A. Thompson
- Australian Inherited Retinal Disease Registry and DNA BankDepartment of Medical Technology and PhysicsSir Charles Gairdner HospitalNedlandsWestern AustraliaAustralia
| | - Jason Charng
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
| | - Enid Chelva
- Australian Inherited Retinal Disease Registry and DNA BankDepartment of Medical Technology and PhysicsSir Charles Gairdner HospitalNedlandsWestern AustraliaAustralia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
| | - Shang‐Chih Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
| | - Dan Zhang
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
| | - Terri L. McLaren
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
- Australian Inherited Retinal Disease Registry and DNA BankDepartment of Medical Technology and PhysicsSir Charles Gairdner HospitalNedlandsWestern AustraliaAustralia
| | - Tina M. Lamey
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
- Australian Inherited Retinal Disease Registry and DNA BankDepartment of Medical Technology and PhysicsSir Charles Gairdner HospitalNedlandsWestern AustraliaAustralia
| | - Ian J. Constable
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
- Department of OphthalmologySir Charles Gairdner HospitalNedlandsWestern AustraliaAustralia
| | - John N. De Roach
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
- Australian Inherited Retinal Disease Registry and DNA BankDepartment of Medical Technology and PhysicsSir Charles Gairdner HospitalNedlandsWestern AustraliaAustralia
| | - May Thandar Aung‐Htut
- Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochWestern AustraliaAustralia
- Centre for Neuromuscular and Neurological DisordersThe University of Western Australia and Perron Institute for Neurological and Translational ScienceNedlandsWestern AustraliaAustralia
| | - Abbie Adams
- Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochWestern AustraliaAustralia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochWestern AustraliaAustralia
- Centre for Neuromuscular and Neurological DisordersThe University of Western Australia and Perron Institute for Neurological and Translational ScienceNedlandsWestern AustraliaAustralia
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative TherapeuticsMurdoch UniversityMurdochWestern AustraliaAustralia
- Centre for Neuromuscular and Neurological DisordersThe University of Western Australia and Perron Institute for Neurological and Translational ScienceNedlandsWestern AustraliaAustralia
| | - Fred K. Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute)The University of Western AustraliaNedlandsWestern AustraliaAustralia
- Australian Inherited Retinal Disease Registry and DNA BankDepartment of Medical Technology and PhysicsSir Charles Gairdner HospitalNedlandsWestern AustraliaAustralia
- Department of OphthalmologyRoyal Perth HospitalPerthWestern AustraliaAustralia
- Department of OphthalmologyPerth Children's HospitalNedlandsWestern AustraliaAustralia
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26
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Greer K, Johnsen R, Nevo Y, Fellig Y, Fletcher S, Wilton SD. Single Exon Skipping Can Address a Multi-Exon Duplication in the Dystrophin Gene. Int J Mol Sci 2020; 21:ijms21124511. [PMID: 32630425 PMCID: PMC7350004 DOI: 10.3390/ijms21124511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease typically caused by protein-truncating mutations that preclude synthesis of a functional dystrophin. Exonic deletions are the most common type of DMD lesion, however, whole exon duplications account for between 10–15% of all reported mutations. Here, we describe in vitro evaluation of antisense oligonucleotide-induced splice switching strategies to re-frame the transcript disrupted by a multi-exon duplication within the DMD gene. Phosphorodiamidate morpholino oligomers and phosphorodiamidate morpholino oligomers coupled to a cell penetrating peptide were evaluated in a Duchenne muscular dystrophy patient cell strain carrying an exon 14–17 duplication. Two strategies were employed; the conventional approach was to remove both copies of exon 17 in addition to exon 18, and the second strategy was to remove only the first copy of exon 17. Both approaches result in a larger than normal but in-frame DMD transcript, but surprisingly, the removal of only the first exon 17 appeared to be more efficient in restoring dystrophin, as determined using western blotting. The emergence of a normal sized DMD mRNA transcript that was not apparent in untreated samples may have arisen from back splicing and could also account for some of the dystrophin protein being produced.
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Affiliation(s)
- Kane Greer
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth 6009, Australia
| | - Russell Johnsen
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth 6009, Australia
| | - Yoram Nevo
- Institute of Neurology, Schneider Children's Medical Center of Israel, Tel-Aviv University,Tel-Aviv 62919, Israel
| | - Yakov Fellig
- Pathology Department, Hadassah-Hebrew-University Medical Center, Jerusalem 91120, Israel
| | - Susan Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth 6009, Australia
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Perth 6009, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch 6150, Australia
- Perron Institute for Neurological and Translational Science, Perth 6009, Australia
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Perth 6009, Australia
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27
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Aung-Htut MT, Ham KA, Tchan M, Johnsen R, Schnell FJ, Fletcher S, Wilton SD. Splice modulating antisense oligonucleotides restore some acid-alpha-glucosidase activity in cells derived from patients with late-onset Pompe disease. Sci Rep 2020; 10:6702. [PMID: 32317649 PMCID: PMC7174337 DOI: 10.1038/s41598-020-63461-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/30/2020] [Indexed: 01/16/2023] Open
Abstract
Pompe disease is caused by mutations in the GAA gene, resulting in deficient lysosomal acid-α-glucosidase activity in patients, and a progressive decline in mobility and respiratory function. Enzyme replacement therapy is one therapeutic option, but since not all patients respond to this treatment, alternative interventions should be considered. One GAA mutation, c.-32-13T > G, impacts upon normal exon 2 splicing and is found in two-thirds of late-onset cases. We and others have explored a therapeutic strategy using splice modulating phosphorodiamidate morpholino oligomers to enhance GAA exon 2 inclusion in the mature mRNA of patients with one c.-32-13T > G allele. We designed 20 oligomers and treated fibroblasts derived from five patients to identify an oligomer sequence that maximally increased enzyme activity in all fibroblasts. The most effective splice correcting oligomer was chosen to treat forced-myogenic cells, derived from fibroblasts from nine patients carrying the c.-32-13T > G mutation. After transfection, we show increased levels of the full-length GAA transcript, acid-α-glucosidase protein, and enzyme activity in all patients’ myogenic cells, regardless of the nature of the mutation in the other allele. This data encourages the initiation of clinical trials to assess the therapeutic efficacy of this oligomer for those patients carrying the c.-32-13T > G mutation.
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Affiliation(s)
- May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, 6150, Australia.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, 6009, Australia
| | - Kristin A Ham
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, 6150, Australia.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, 6009, Australia
| | - Michel Tchan
- Genetic Medicine, Westmead Hospital, Sydney, 2145, Australia.,Sydney Medical School, The University of Sydney, Sydney, 2006, Australia
| | - Russell Johnsen
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, 6150, Australia
| | | | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, 6150, Australia. .,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, 6009, Australia.
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, 6150, Australia. .,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, 6009, Australia.
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28
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Theunissen F, Flynn LL, Anderton RS, Mastaglia F, Pytte J, Jiang L, Hodgetts S, Burns DK, Saunders A, Fletcher S, Wilton SD, Akkari PA. Structural Variants May Be a Source of Missing Heritability in sALS. Front Neurosci 2020; 14:47. [PMID: 32082115 PMCID: PMC7005198 DOI: 10.3389/fnins.2020.00047] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/13/2020] [Indexed: 12/11/2022] Open
Abstract
The underlying genetic and molecular mechanisms that drive amyotrophic lateral sclerosis (ALS) remain poorly understood. Structural variants within the genome can play a significant role in neurodegenerative disease risk, such as the repeat expansion in C9orf72 and the tri-nucleotide repeat in ATXN2, both of which are associated with familial and sporadic ALS. Many such structural variants reside in uncharacterized regions of the human genome, and have been under studied. Therefore, characterization of structural variants located in and around genes associated with ALS could provide insight into disease pathogenesis, and lead to the discovery of highly informative genetic tools for stratification in clinical trials. Such genomic variants may provide a deeper understanding of how gene expression can affect disease etiology, disease severity and trajectory, patient response to treatment, and may hold the key to understanding the genetics of sporadic ALS. This article outlines the current understanding of amyotrophic lateral sclerosis genetics and how structural variations may underpin some of the missing heritability of this disease.
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Affiliation(s)
- Frances Theunissen
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,School of Human Sciences, University of Western Australia, Nedlands, WA, Australia
| | - Loren L Flynn
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Ryan S Anderton
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,School of Health Sciences, Institute for Health Research, University of Notre Dame Australia, Fremantle, WA, Australia
| | - Frank Mastaglia
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia
| | - Julia Pytte
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,School of Human Sciences, University of Western Australia, Nedlands, WA, Australia
| | - Leanne Jiang
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,School of Biological Sciences, University of Western Australia, Nedlands, WA, Australia
| | - Stuart Hodgetts
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,School of Human Sciences, University of Western Australia, Nedlands, WA, Australia
| | - Daniel K Burns
- Zinfandel Pharmaceuticals, Chapel Hill, NC, United States
| | - Ann Saunders
- Zinfandel Pharmaceuticals, Chapel Hill, NC, United States
| | - Sue Fletcher
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Steve D Wilton
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Patrick Anthony Akkari
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
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29
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Aung-Htut MT, Ham KA, Tchan MC, Fletcher S, Wilton SD. Novel Mutations Found in Individuals with Adult-Onset Pompe Disease. Genes (Basel) 2020; 11:genes11020135. [PMID: 32012848 PMCID: PMC7073677 DOI: 10.3390/genes11020135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/19/2019] [Accepted: 01/23/2020] [Indexed: 11/16/2022] Open
Abstract
Pompe disease, or glycogen storage disease II is a rare, progressive disease leading to skeletal muscle weakness due to deficiency of the acid α-1,4-glucosidase enzyme (GAA). The severity of disease and observed time of onset is subject to the various combinations of heterozygous GAA alleles. Here we have characterized two novel mutations: c.2074C>T and c.1910_1918del, and a previously reported c.1082C>G mutation of uncertain clinical significance. These mutations were found in three unrelated patients with adult-onset Pompe disease carrying the common c.-32-13T>G mutation. The c.2074 C>T nonsense mutation has obvious consequences on GAA expression but the c.1910_1918del (deletion of 3 amino acids) and c.1082C>G missense variants are more subtle DNA changes with catastrophic consequences on GAA activity. Molecular and clinical analyses from the three patients corresponded with the anticipated pathogenicity of each mutation.
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Affiliation(s)
- May T. Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150, Australia; (M.T.A.-H.); (K.A.H.); (S.F.)
- Perron Institute for Neurological and Translational Science and The University of Western Australia, Perth 6009, Australia
| | - Kristin A. Ham
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150, Australia; (M.T.A.-H.); (K.A.H.); (S.F.)
| | - Michel C. Tchan
- Genetic Medicine, Westmead Hospital, Sydney 2145, Australia;
- Sydney Medical School, The University of Sydney, Sydney 2006, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150, Australia; (M.T.A.-H.); (K.A.H.); (S.F.)
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150, Australia; (M.T.A.-H.); (K.A.H.); (S.F.)
- Perron Institute for Neurological and Translational Science and The University of Western Australia, Perth 6009, Australia
- Correspondence:
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Zaw K, Greer K, Aung-Htut MT, Mitrpant C, Veedu RN, Fletcher S, Wilton SD. Consequences of Making the Inactive Active Through Changes in Antisense Oligonucleotide Chemistries. Front Genet 2019; 10:1249. [PMID: 31956327 PMCID: PMC6951410 DOI: 10.3389/fgene.2019.01249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/13/2019] [Indexed: 01/02/2023] Open
Abstract
Antisense oligonucleotides are short, single-stranded nucleic acid analogues that can interfere with pre-messenger RNA (pre-mRNA) processing and induce excision of a targeted exon from the mature transcript. When developing a panel of antisense oligonucleotides to skip every dystrophin exon, we found great variation in splice switching efficiencies, with some antisense oligonucleotides ineffective, even when directed to canonical splice sites and transfected into cells at high concentrations. In this study, we re-evaluated some of these ineffective antisense oligonucleotide sequences after incorporation of locked nucleic acid residues to increase annealing potential. Antisense oligonucleotides targeting exons 16, 23, and 51 of human DMD transcripts were synthesized as two different chemistries, 2′-O-methyl modified bases on a phosphorothioate backbone or mixmers containing several locked nucleic acid residues, which were then transfected into primary human myotubes, and DMD transcripts were analyzed for exon skipping. The ineffective 2′-O-methyl modified antisense oligonucleotides induced no detectable exon skipping, while all corresponding mixmers did induce excision of the targeted exons. Interestingly, the mixmer targeting exon 51 induced two unexpected transcripts arising from partial skipping of exon 51 with retention of 95 or 188 bases from the 5′ region of exon 51. These results indicated that locked nucleic acid/2′-O-methyl mixmers are more effective at inducing exon skipping, however, this improvement may come at the cost of activating alternative cryptic splice sites and off-target effects on gene expression.
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Affiliation(s)
- Khine Zaw
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kane Greer
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - Chalermchai Mitrpant
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - Rakesh N Veedu
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.,Perron Institute for Neurological and Translational Science and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
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Mejzini R, Flynn LL, Pitout IL, Fletcher S, Wilton SD, Akkari PA. ALS Genetics, Mechanisms, and Therapeutics: Where Are We Now? Front Neurosci 2019; 13:1310. [PMID: 31866818 PMCID: PMC6909825 DOI: 10.3389/fnins.2019.01310] [Citation(s) in RCA: 411] [Impact Index Per Article: 82.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 11/22/2019] [Indexed: 12/11/2022] Open
Abstract
The scientific landscape surrounding amyotrophic lateral sclerosis (ALS) continues to shift as the number of genes associated with the disease risk and pathogenesis, and the cellular processes involved, continues to grow. Despite decades of intense research and over 50 potentially causative or disease-modifying genes identified, etiology remains unexplained and treatment options remain limited for the majority of ALS patients. Various factors have contributed to the slow progress in understanding and developing therapeutics for this disease. Here, we review the genetic basis of ALS, highlighting factors that have contributed to the elusiveness of genetic heritability. The most commonly mutated ALS-linked genes are reviewed with an emphasis on disease-causing mechanisms. The cellular processes involved in ALS pathogenesis are discussed, with evidence implicating their involvement in ALS summarized. Past and present therapeutic strategies and the benefits and limitations of the model systems available to ALS researchers are discussed with future directions for research that may lead to effective treatment strategies outlined.
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Affiliation(s)
- Rita Mejzini
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- The Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Loren L. Flynn
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- The Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - Ianthe L. Pitout
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- The Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- The Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- The Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
| | - P. Anthony Akkari
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- The Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, WA, Australia
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McIntosh CS, Aung-Htut MT, Fletcher S, Wilton SD. Removal of the Polyglutamine Repeat of Ataxin-3 by Redirecting pre-mRNA Processing. Int J Mol Sci 2019; 20:ijms20215434. [PMID: 31683630 PMCID: PMC6862616 DOI: 10.3390/ijms20215434] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 02/06/2023] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is a devastating neurodegenerative disease for which there is currently no cure, nor effective treatment strategy. One of nine polyglutamine disorders known to date, SCA3 is clinically heterogeneous and the main feature is progressive ataxia, which in turn affects speech, balance and gait of the affected individual. SCA3 is caused by an expanded polyglutamine tract in the ataxin-3 protein, resulting in conformational changes that lead to toxic gain of function. The expanded glutamine tract is located at the 5′ end of the penultimate exon (exon 10) of ATXN3 gene transcript. Other studies reported removal of the expanded glutamine tract using splice switching antisense oligonucleotides. Here, we describe improved efficiency in the removal of the toxic polyglutamine tract of ataxin-3 in vitro using phosphorodiamidate morpholino oligomers, when compared to antisense oligonucleotides composed of 2′-O-methyl modified bases on a phosphorothioate backbone. Significant downregulation of both the expanded and non-expanded protein was induced by the morpholino antisense oligomer, with a greater proportion of ataxin-3 protein missing the polyglutamine tract. With growing concerns over toxicity associated with long-term administration of phosphorothioate oligonucleotides, the use of a phosphorodiamidate morpholino oligomer may be preferable for clinical application. These results suggest that morpholino oligomers may provide greater therapeutic benefit for the treatment of spinocerebellar ataxia type 3, without toxic effects.
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Affiliation(s)
- Craig S McIntosh
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch WA 6150, Australia.
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands WA 6009, Australia.
| | - May Thandar Aung-Htut
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch WA 6150, Australia.
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands WA 6009, Australia.
| | - Sue Fletcher
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch WA 6150, Australia.
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands WA 6009, Australia.
| | - Steve D Wilton
- Molecular Therapy Laboratory, Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch WA 6150, Australia.
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands WA 6009, Australia.
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Aung-Htut MT, McIntosh CS, West KA, Fletcher S, Wilton SD. In Vitro Validation of Phosphorodiamidate Morpholino Oligomers. Molecules 2019; 24:E2922. [PMID: 31408997 PMCID: PMC6719133 DOI: 10.3390/molecules24162922] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 01/14/2023] Open
Abstract
One of the crucial aspects of screening antisense oligonucleotides destined for therapeutic application is confidence that the antisense oligomer is delivered efficiently into cultured cells. Efficient delivery is particularly vital for antisense phosphorodiamidate morpholino oligomers, which have a neutral backbone, and are known to show poor gymnotic uptake. Here, we report several methods to deliver these oligomers into cultured cells. Although 4D-Nucleofector™ or Neon™ electroporation systems provide efficient delivery and use lower amounts of phosphorodiamidate morpholino oligomer, both systems are costly. We show that some readily available transfection reagents can be used to deliver phosphorodiamidate morpholino oligomers as efficiently as the electroporation systems. Among the transfection reagents tested, we recommend Lipofectamine 3000™ for delivering phosphorodiamidate morpholino oligomers into fibroblasts and Lipofectamine 3000™ or Lipofectamine 2000™ for myoblasts/myotubes. We also provide optimal programs for nucleofection into various cell lines using the P3 Primary Cell 4D-Nucleofector™ X Kit (Lonza), as well as antisense oligomers that redirect expression of ubiquitously expressed genes that may be used as positive treatments for human and murine cell transfections.
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Affiliation(s)
- May T Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
- Perron Institute for Neurological and Translational Science, the University of Western Australia, Perth, WA 6009, Australia
| | - Craig S McIntosh
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia.
- Perron Institute for Neurological and Translational Science, the University of Western Australia, Perth, WA 6009, Australia.
| | - Kristin A West
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
- Perron Institute for Neurological and Translational Science, the University of Western Australia, Perth, WA 6009, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
- Perron Institute for Neurological and Translational Science, the University of Western Australia, Perth, WA 6009, Australia
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Abstract
Recent approvals of oligonucleotide analogue drugs to alter gene expression have been welcomed by patient communities but not universally supported. These compounds represent a class of drugs that are designed to target a specific gene transcript, and they include a number of chemical entities to evoke different antisense mechanisms, depending upon the disease aetiology. To date, oligonucleotide therapeutics that are in the clinic or at advanced stages of translation target rare diseases, posing challenges to clinical trial design, recruitment and evaluation and requiring new evaluation paradigms. This review discusses the currently available and emerging therapeutics that alter exon selection through an effect on pre-mRNA splicing and explores emerging concerns over safety and efficacy. Although modification of synthetic nucleic acids destined for therapeutic application is common practice to protect against nuclease degradation and to influence drug function, such modifications may also confer unexpected physicochemical and biological properties. Negatively charged oligonucleotides have a strong propensity to bind extra- and intra-cellular proteins, whereas those analogues with a neutral backbone show inefficient cellular uptake but excellent safety profiles. In addition, the potential for incorporation of chemically modified nucleic acid monomers, yielded by nuclease degradation of exogenous oligonucleotides, into biomolecules has been raised and the possibility not entirely discounted. We conclude with a commentary on the ongoing efforts to develop novel antisense compounds and enhance oligonucleotide delivery in order to further improve efficacy and accelerate implementation of antisense therapeutics for human disease.
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Affiliation(s)
| | - Loren L Flynn
- Murdoch University, Murdoch, WA, 6150, Australia.,The University of Western Australia, Nedlands, WA, 6009, Australia.,Perron Institute, Nedlands, WA, 6009, Australia
| | - Steve D Wilton
- Murdoch University, Murdoch, WA, 6150, Australia.,The University of Western Australia, Nedlands, WA, 6009, Australia.,Perron Institute, Nedlands, WA, 6009, Australia
| | - Sue Fletcher
- Murdoch University, Murdoch, WA, 6150, Australia.,The University of Western Australia, Nedlands, WA, 6009, Australia.,Perron Institute, Nedlands, WA, 6009, Australia
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35
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Bolduc V, Foley AR, Solomon-Degefa H, Sarathy A, Donkervoort S, Hu Y, Chen GS, Sizov K, Nalls M, Zhou H, Aguti S, Cummings BB, Lek M, Tukiainen T, Marshall JL, Regev O, Marek-Yagel D, Sarkozy A, Butterfield RJ, Jou C, Jimenez-Mallebrera C, Li Y, Gartioux C, Mamchaoui K, Allamand V, Gualandi F, Ferlini A, Hanssen E, Wilton SD, Lamandé SR, MacArthur DG, Wagener R, Muntoni F, Bönnemann CG. A recurrent COL6A1 pseudoexon insertion causes muscular dystrophy and is effectively targeted by splice-correction therapies. JCI Insight 2019; 4:124403. [PMID: 30895940 DOI: 10.1172/jci.insight.124403] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/12/2019] [Indexed: 12/27/2022] Open
Abstract
The clinical application of advanced next-generation sequencing technologies is increasingly uncovering novel classes of mutations that may serve as potential targets for precision medicine therapeutics. Here, we show that a deep intronic splice defect in the COL6A1 gene, originally discovered by applying muscle RNA sequencing in patients with clinical findings of collagen VI-related dystrophy (COL6-RD), inserts an in-frame pseudoexon into COL6A1 mRNA, encodes a mutant collagen α1(VI) protein that exerts a dominant-negative effect on collagen VI matrix assembly, and provides a unique opportunity for splice-correction approaches aimed at restoring normal gene expression. Using splice-modulating antisense oligomers, we efficiently skipped the pseudoexon in patient-derived fibroblast cultures and restored a wild-type matrix. Similarly, we used CRISPR/Cas9 to precisely delete an intronic sequence containing the pseudoexon and efficiently abolish its inclusion while preserving wild-type splicing. Considering that this splice defect is emerging as one of the single most frequent mutations in COL6-RD, the design of specific and effective splice-correction therapies offers a promising path for clinical translation.
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Affiliation(s)
- Véronique Bolduc
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Herimela Solomon-Degefa
- Center for Biochemistry, Faculty of Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Apurva Sarathy
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Ying Hu
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Grace S Chen
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Katherine Sizov
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Matthew Nalls
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Haiyan Zhou
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, United Kingdom.,Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Sara Aguti
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, United Kingdom
| | - Beryl B Cummings
- Analytical and Translation Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.,Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Monkol Lek
- Analytical and Translation Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Taru Tukiainen
- Analytical and Translation Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.,Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Jamie L Marshall
- Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Oded Regev
- Courant Institute of Mathematical Sciences, New York University, New York, USA
| | - Dina Marek-Yagel
- Metabolic Disease Unit, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel-Hashomer, Israel
| | - Anna Sarkozy
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, United Kingdom
| | - Russell J Butterfield
- Department of Neurology and Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Cristina Jou
- Pathology Department and Biobanc de l'Hospital Infantil Sant Joan de Déu per a la Investigació, Hospital Sant Joan de Déu, Barcelona, Spain.,Neuromuscular Unit, Neuropediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain.,CIBERER (ISCIII), Madrid, Spain
| | - Cecilia Jimenez-Mallebrera
- Neuromuscular Unit, Neuropediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain.,CIBERER (ISCIII), Madrid, Spain
| | - Yan Li
- Peptide/Protein Sequencing Facility, National Institute of Neurological Disorder and Stroke, NIH, Bethesda, Maryland, USA
| | - Corine Gartioux
- Sorbonne Université, Inserm, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris, France
| | - Kamel Mamchaoui
- Sorbonne Université, Inserm, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris, France
| | - Valérie Allamand
- Sorbonne Université, Inserm, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris, France
| | - Francesca Gualandi
- Medical Genetics Unit, Department of Medical Science, University of Ferrara, Ferrara, Italy
| | - Alessandra Ferlini
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, United Kingdom.,Medical Genetics Unit, Department of Medical Science, University of Ferrara, Ferrara, Italy
| | - Eric Hanssen
- Bio21 Advanced Microscopy Facility, The University of Melbourne, Melbourne, Australia
| | | | - Steve D Wilton
- Centre for Molecular Medicine and Therapeutics, Murdoch University, Perth, Australia.,Perron Institute for Neurological and Translational Science, University of Western Australia, Perth, Australia
| | - Shireen R Lamandé
- Murdoch Children's Research Institute, Parkville, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Australia
| | - Daniel G MacArthur
- Analytical and Translation Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.,Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Raimund Wagener
- Center for Biochemistry, Faculty of Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, United Kingdom.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, United Kingdom
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
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Callus BA, Finch-Edmondson ML, Fletcher S, Wilton SD. YAPping about and not forgetting TAZ. FEBS Lett 2019; 593:253-276. [PMID: 30570758 DOI: 10.1002/1873-3468.13318] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/05/2018] [Accepted: 12/14/2018] [Indexed: 12/14/2022]
Abstract
The Hippo pathway has emerged as a major eukaryotic signalling pathway and is increasingly the subject of intense interest, as are the key effectors of canonical Hippo signalling, YES-associated protein (YAP) and TAZ. The Hippo pathway has key roles in diverse biological processes, including network signalling regulation, development, organ growth, tissue repair and regeneration, cancer, stem cell regulation and mechanotransduction. YAP and TAZ are multidomain proteins and function as transcriptional coactivators of key genes to evoke their biological effects. YAP and TAZ interact with numerous partners and their activities are controlled by a complex set of processes. This review provides an overview of Hippo signalling and its role in growth. In particular, the functional domains of YAP and TAZ and the complex mechanisms that regulate their protein stability and activity are discussed. Notably, the similarities and key differences are highlighted between the two paralogues including which partner proteins interact with which functional domains to regulate their activity.
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Affiliation(s)
| | - Megan L Finch-Edmondson
- Discipline of Child and Adolescent Health, Children's Hospital at Westmead Clinical School, University of Sydney Medical School, Australia.,Cerebral Palsy Alliance Research Institute, University of Sydney, Australia
| | - Sue Fletcher
- Centre for Comparative Genomics, Murdoch University, Australia.,Perron Institute for Neurological and Translational Research, Nedlands, Australia
| | - Steve D Wilton
- Centre for Comparative Genomics, Murdoch University, Australia.,Perron Institute for Neurological and Translational Research, Nedlands, Australia
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Abstract
The Duchenne muscular dystrophy community has recently seen the first approved therapy for the restoration of dystrophin, based on its ability to increase levels of dystrophin protein, as determined by western blot. The approval, along with the initiation of clinical trials evaluating other dystrophin-restoring therapies, highlights the importance of accurate dystrophin quantitation. Nonoptimized western blot methods can reflect inaccurate results, especially in the quantitation of low dystrophin levels. A few key changes to standards and data analysis parameters can result in a low level of dystrophin (<0.5% of a healthy biopsy) being inaccurately interpreted as >20% of the levels reported in healthy human muscle. A review of the dystrophin western blot data on Duchenne and Becker muscular dystrophy biopsies is conducted, along with a thorough investigation of methodologies to quantify dystrophin.
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Le BT, Raguraman P, Kosbar TR, Fletcher S, Wilton SD, Veedu RN. Antisense Oligonucleotides Targeting Angiogenic Factors as Potential Cancer Therapeutics. Mol Ther Nucleic Acids 2018; 14:142-157. [PMID: 30594893 PMCID: PMC6307321 DOI: 10.1016/j.omtn.2018.11.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 02/07/2023]
Abstract
Cancer is one of the leading causes of death worldwide, and conventional cancer therapies such as surgery, chemotherapy, and radiotherapy do not address the underlying molecular pathologies, leading to inadequate treatment and tumor recurrence. Angiogenic factors, such as EGF, PDGF, bFGF, TGF-β, TGF-α, VEGF, endoglin, and angiopoietins, play important roles in regulating tumor development and metastasis, and they serve as potential targets for developing cancer therapeutics. Nucleic acid-based therapeutic strategies have received significant attention in the last two decades, and antisense oligonucleotide-mediated intervention is a prominent therapeutic approach for targeted manipulation of gene expression. Clinical benefits of antisense oligonucleotides have been recognized by the U.S. Food and Drug Administration, with full or conditional approval of Vitravene, Kynamro, Exondys51, and Spinraza. Herein we review the scope of antisense oligonucleotides that target angiogenic factors toward tackling solid cancers.
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Affiliation(s)
- Bao T Le
- Centre for Comparative Genomics, Murdoch University, Murdoch, WA 6150, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
| | - Prithi Raguraman
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
| | - Tamer R Kosbar
- Centre for Comparative Genomics, Murdoch University, Murdoch, WA 6150, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
| | - Susan Fletcher
- Centre for Comparative Genomics, Murdoch University, Murdoch, WA 6150, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
| | - Steve D Wilton
- Centre for Comparative Genomics, Murdoch University, Murdoch, WA 6150, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
| | - Rakesh N Veedu
- Centre for Comparative Genomics, Murdoch University, Murdoch, WA 6150, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia.
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Li D, Mastaglia FL, Fletcher S, Wilton SD. Precision Medicine through Antisense Oligonucleotide-Mediated Exon Skipping. Trends Pharmacol Sci 2018; 39:982-994. [PMID: 30282590 DOI: 10.1016/j.tips.2018.09.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/30/2018] [Accepted: 09/04/2018] [Indexed: 12/11/2022]
Abstract
Clinical implementation of two recently approved antisense RNA therapeutics - Exondys51® to treat Duchenne muscular dystrophy (Duchenne MD) and Spinraza® as a treatment for spinal muscular atrophy (SMA) - highlights the therapeutic potential of antisense oligonucleotides (ASOs). As shown in the Duchenne and Becker cases, the identification and specific removal of 'dispensable' exons by exon-skipping ASOs could potentially bypass lethal mutations in other genes and bring clinical benefits to affected individuals carrying amenable mutations. In this review, we discuss the potential of therapeutic alternative splicing, with a particular focus on targeted exon skipping using Duchenne MD as an example, and speculate on new applications for other inherited rare diseases where redundant or dispensable exons may be amenable to exon-skipping ASO intervention as precision medicine.
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Affiliation(s)
- Dunhui Li
- Centre for Comparative Genomics, Murdoch University, Perth 6050, Australia; Perron Institute for Neurological and Translational Science, University of Western Australia, Perth 6000, Australia
| | - Frank L Mastaglia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Perth 6000, Australia
| | - Sue Fletcher
- Centre for Comparative Genomics, Murdoch University, Perth 6050, Australia; Perron Institute for Neurological and Translational Science, University of Western Australia, Perth 6000, Australia
| | - Steve D Wilton
- Centre for Comparative Genomics, Murdoch University, Perth 6050, Australia; Perron Institute for Neurological and Translational Science, University of Western Australia, Perth 6000, Australia.
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Wein N, Vulin A, Findlay AR, Gumienny F, Huang N, Wilton SD, Flanigan KM. Efficient Skipping of Single Exon Duplications in DMD Patient-Derived Cell Lines Using an Antisense Oligonucleotide Approach. J Neuromuscul Dis 2018; 4:199-207. [PMID: 28869484 DOI: 10.3233/jnd-170233] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Exon skipping strategies in Duchenne muscular dystrophy (DMD) have largely been directed toward altering splicing of exons flanking out-of-frame deletions, with the goal of restoring an open mRNA reading frame that leads to production of an internally deleted but partially functional dystrophin protein. OBJECTIVE We sought to apply exon skipping to duplication mutations, assuming that the inherently limited efficiency of antisense oligonucleotide-induced exon skipping would more frequently skip a single copy of a duplicated exon, rather than both and result in significant amounts of wild-type DMD mRNA. METHODS We tested this hypothesis in fibroblast cell lines derived from patients with a variety of single or multiple exon duplications that have been modified to allow transdifferentiation into a myogenic lineage. RESULTS Using a variety of 2'O-methyl antisense oligonucleotides, significant skipping was induced for each duplication leading to a wild-type transcript as a major mRNA product. CONCLUSIONS This study provides another proof of concept for the feasibility of therapeutic skipping in patients carrying exon duplications in order to express wild-type, full-length mRNA, although careful evaluation of the skipping efficiency should be performed as some exons are easier to skip than others. Such a personalized strategy is expected to be highly beneficial for this subset of DMD patients, compared to inducing expression of an internally-deleted dystrophin.
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Affiliation(s)
- Nicolas Wein
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Adeline Vulin
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Andrew R Findlay
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Felecia Gumienny
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Nianyuan Huang
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Steve D Wilton
- Perron Institute for Neurological and Translational Science, Center for Comparative Genomics, Murdoch University, Perth, Australia
| | - Kevin M Flanigan
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA.,Department of Neurology, The Ohio State University, Columbus, OH, USA
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Martinovich KM, Shaw NC, Kicic A, Schultz A, Fletcher S, Wilton SD, Stick SM. The potential of antisense oligonucleotide therapies for inherited childhood lung diseases. Mol Cell Pediatr 2018; 5:3. [PMID: 29411170 PMCID: PMC5801198 DOI: 10.1186/s40348-018-0081-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/25/2018] [Indexed: 01/05/2023] Open
Abstract
Antisense oligonucleotides are an emerging therapeutic option to treat diseases with known genetic origin. In the age of personalised medicines, antisense oligonucleotides can sometimes be designed to target and bypass or overcome a patient's genetic mutation, in particular those lesions that compromise normal pre-mRNA processing. Antisense oligonucleotides can alter gene expression through a variety of mechanisms as determined by the chemistry and antisense oligomer design. Through targeting the pre-mRNA, antisense oligonucleotides can alter splicing and induce a specific spliceoform or disrupt the reading frame, target an RNA transcript for degradation through RNaseH activation, block ribosome initiation of protein translation or disrupt miRNA function. The recent accelerated approval of eteplirsen (renamed Exondys 51™) by the Food and Drug Administration, for the treatment of Duchenne muscular dystrophy, and nusinersen, for the treatment of spinal muscular atrophy, herald a new and exciting era in splice-switching antisense oligonucleotide applications to treat inherited diseases. This review considers the potential of antisense oligonucleotides to treat inherited lung diseases of childhood with a focus on cystic fibrosis and disorders of surfactant protein metabolism.
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Affiliation(s)
- Kelly M. Martinovich
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Centre for Comparative Genomics, Murdoch University, Murdoch, Western Australia 6150 Australia
| | - Nicole C. Shaw
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Centre for Comparative Genomics, Murdoch University, Murdoch, Western Australia 6150 Australia
| | - Anthony Kicic
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Department of Respiratory Medicine, Princess Margaret Hospital for Children, Subiaco, Western Australia 6008 Australia
- School of Public Health, Curtin University, Bentley, Western Australia 6102 Australia
| | - André Schultz
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Department of Respiratory Medicine, Princess Margaret Hospital for Children, Subiaco, Western Australia 6008 Australia
| | - Sue Fletcher
- Perron Institute for Neurological and Translational Sciences, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Centre for Comparative Genomics, Murdoch University, Murdoch, Western Australia 6150 Australia
| | - Steve D. Wilton
- Perron Institute for Neurological and Translational Sciences, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Centre for Comparative Genomics, Murdoch University, Murdoch, Western Australia 6150 Australia
| | - Stephen M. Stick
- School of Paediatrics and Child Health, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Telethon Kids Institute, Centre for Health Research, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia, Nedlands, Western Australia 6009 Australia
- Department of Respiratory Medicine, Princess Margaret Hospital for Children, Subiaco, Western Australia 6008 Australia
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Flynn LL, Mitrpant C, Pitout IL, Fletcher S, Wilton SD. Antisense Oligonucleotide-Mediated Terminal Intron Retention of the SMN2 Transcript. Mol Ther Nucleic Acids 2018; 11:91-102. [PMID: 29858094 PMCID: PMC5854547 DOI: 10.1016/j.omtn.2018.01.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/25/2018] [Accepted: 01/25/2018] [Indexed: 12/21/2022]
Abstract
The severe childhood disease spinal muscular atrophy (SMA) arises from the homozygous loss of the survival motor neuron 1 gene (SMN1). A homologous gene potentially encoding an identical protein, SMN2 can partially compensate for the loss of SMN1; however, the exclusion of a critical exon in the coding region during mRNA maturation results in insufficient levels of functional protein. The rate of transcription is known to influence the alternative splicing of gene transcripts, with a fast transcription rate correlating to an increase in alternative splicing. Conversely, a slower transcription rate is more likely to result in the inclusion of all exons in the transcript. Targeting SMN2 with antisense oligonucleotides to influence the processing of terminal exon 8 could be a way to slow transcription and induce the inclusion of exon 7. Interestingly, following oligomer treatment of SMA patient fibroblasts, we observed the inclusion of exon 7, as well as intron 7, in the transcript. Because the normal termination codon is located in exon 7, this exon/intron 7-SMN2 transcript should encode the normal protein and only carry a longer 3′ UTR. Further studies showed the extra 3′ UTR length contained a number of regulatory motifs that modify transcript and protein regulation, leading to translational repression of SMN. Although unlikely to provide therapeutic benefit for SMA patients, this novel technique for gene regulation could provide another avenue for the repression of undesirable gene expression in a variety of other diseases.
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Affiliation(s)
- Loren L Flynn
- Centre for Comparative Genomics, Murdoch University, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Chalermchai Mitrpant
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia; Department of Biochemistry, Mahidol University, Bangkok, Thailand
| | - Ianthe L Pitout
- Centre for Comparative Genomics, Murdoch University, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Comparative Genomics, Murdoch University, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Steve D Wilton
- Centre for Comparative Genomics, Murdoch University, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia.
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Mishra MK, Loro E, Sengupta K, Wilton SD, Khurana TS. Functional improvement of dystrophic muscle by repression of utrophin: let-7c interaction. PLoS One 2017; 12:e0182676. [PMID: 29045431 PMCID: PMC5646768 DOI: 10.1371/journal.pone.0182676] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 07/21/2017] [Indexed: 02/02/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a fatal genetic disease caused by an absence of the 427kD muscle-specific dystrophin isoform. Utrophin is the autosomal homolog of dystrophin and when overexpressed, can compensate for the absence of dystrophin and rescue the dystrophic phenotype of the mdx mouse model of DMD. Utrophin is subject to miRNA mediated repression by several miRNAs including let-7c. Inhibition of utrophin: let-7c interaction is predicted to 'repress the repression' and increase utrophin expression. We developed and tested the ability of an oligonucleotide, composed of 2'-O-methyl modified bases on a phosphorothioate backbone, to anneal to the utrophin 3'UTR and prevent let-7c miRNA binding, thereby upregulating utrophin expression and improving the dystrophic phenotype in vivo. Suppression of utrophin: let-7c interaction using bi-weekly intraperitoneal injections of let7 site blocking oligonucleotides (SBOs) for 1 month in the mdx mouse model for DMD, led to increased utrophin expression along with improved muscle histology, decreased fibrosis and increased specific force. The functional improvement of dystrophic muscle achieved using let7-SBOs suggests a novel utrophin upregulation-based therapeutic strategy for DMD.
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Affiliation(s)
- Manoj K. Mishra
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Emanuele Loro
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kasturi Sengupta
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Steve D. Wilton
- Perron Institute for Neurological and Translational Science, University of Western Australia, Perth, Australia
- Centre for Comparative Genomics, Murdoch University, Perth, Australia
| | - Tejvir S. Khurana
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Huang D, Fletcher S, Wilton SD, Palmer N, McLenachan S, Mackey DA, Chen FK. Inherited Retinal Disease Therapies Targeting Precursor Messenger Ribonucleic Acid. Vision (Basel) 2017; 1:vision1030022. [PMID: 31740647 PMCID: PMC6836112 DOI: 10.3390/vision1030022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 07/24/2017] [Accepted: 08/24/2017] [Indexed: 02/07/2023] Open
Abstract
Inherited retinal diseases are an extremely diverse group of genetically and phenotypically heterogeneous conditions characterized by variable maturation of retinal development, impairment of photoreceptor cell function and gradual loss of photoreceptor cells and vision. Significant progress has been made over the last two decades in identifying the many genes implicated in inherited retinal diseases and developing novel therapies to address the underlying genetic defects. Approximately one-quarter of exonic mutations related to human inherited diseases are likely to induce aberrant splicing products, providing opportunities for the development of novel therapeutics that target splicing processes. The feasibility of antisense oligomer mediated splice intervention to treat inherited diseases has been demonstrated in vitro, in vivo and in clinical trials. In this review, we will discuss therapeutic approaches to treat inherited retinal disease, including strategies to correct splicing and modify exon selection at the level of pre-mRNA. The challenges of clinical translation of this class of emerging therapeutics will also be discussed.
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Affiliation(s)
- Di Huang
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Sue Fletcher
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Steve D. Wilton
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Norman Palmer
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
| | - David A. Mackey
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
| | - Fred K. Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
- Department of Ophthalmology, Royal Perth Hospital, Perth 6000, Australia
- Correspondence: ; Tel.: +61-8-9381-0817
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McIntosh CS, Aung Htut MT, Fletcher S, Fletcher S, Wilton SD. Polyglutamine ataxias: From Clinical and Molecular Features to Current Therapeutic Strategies. ACTA ACUST UNITED AC 2017. [DOI: 10.4172/2157-7412.1000319] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
INTRODUCTION Antisense nucleic acid analogues can interact with pre-mRNA motifs and influence exon or splice site selection and thereby alter gene expression. Design of antisense molecules to target specific motifs can result in either exon exclusion or exon inclusion during splicing. Novel drugs exploiting the antisense concept are targeting rare, life-limiting diseases; however, the potential exists to treat a wide range of conditions by antisense-mediated splice intervention. Areas covered: In this review, the authors discuss the clinical translation of novel molecular therapeutics to address the fatal neuromuscular disorders Duchenne muscular dystrophy and spinal muscular atrophy. The review also highlights difficulties posed by issues pertaining to restricted participant numbers, variable phenotype and disease progression, and the identification and validation of study endpoints. Expert opinion: Translation of novel therapeutics for Duchenne muscular dystrophy and spinal muscular atrophy has been greatly advanced by multidisciplinary research, academic-industry partnerships and in particular, the engagement and support of the patient community. Sponsors, supporters and regulators are cooperating to deliver new drugs and identify and define meaningful outcome measures. Non-conventional and adaptive trial design could be particularly suited to clinical evaluation of novel therapeutics and strategies to treat serious, rare diseases that may be problematic to study using more conventional clinical trial structures.
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Affiliation(s)
- S Fletcher
- a Centre for Neuromuscular and Neurological Disorders , University of Western Australia , Nedlands , Western Australia , Australia.,b Western Australian Neuroscience Research Institute , Nedlands , Western Australia , Australia.,c Centre for Comparative Genomics , Murdoch University , Western Australia , Australia
| | - M I Bellgard
- b Western Australian Neuroscience Research Institute , Nedlands , Western Australia , Australia.,c Centre for Comparative Genomics , Murdoch University , Western Australia , Australia
| | - L Price
- a Centre for Neuromuscular and Neurological Disorders , University of Western Australia , Nedlands , Western Australia , Australia.,b Western Australian Neuroscience Research Institute , Nedlands , Western Australia , Australia.,c Centre for Comparative Genomics , Murdoch University , Western Australia , Australia
| | - A P Akkari
- b Western Australian Neuroscience Research Institute , Nedlands , Western Australia , Australia.,c Centre for Comparative Genomics , Murdoch University , Western Australia , Australia.,d Shiraz Pharmaceuticals, Inc , Chapel Hill , NC , USA
| | - S D Wilton
- a Centre for Neuromuscular and Neurological Disorders , University of Western Australia , Nedlands , Western Australia , Australia.,b Western Australian Neuroscience Research Institute , Nedlands , Western Australia , Australia.,c Centre for Comparative Genomics , Murdoch University , Western Australia , Australia
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Toh ZYC, Thandar Aung-Htut M, Pinniger G, Adams AM, Krishnaswarmy S, Wong BL, Fletcher S, Wilton SD. Deletion of Dystrophin In-Frame Exon 5 Leads to a Severe Phenotype: Guidance for Exon Skipping Strategies. PLoS One 2016; 11:e0145620. [PMID: 26745801 PMCID: PMC4706350 DOI: 10.1371/journal.pone.0145620] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 12/07/2015] [Indexed: 12/03/2022] Open
Abstract
Duchenne and Becker muscular dystrophy severity depends upon the nature and location of the DMD gene lesion and generally correlates with the dystrophin open reading frame. However, there are striking exceptions where an in-frame genomic deletion leads to severe pathology or protein-truncating mutations (nonsense or frame-shifting indels) manifest as mild disease. Exceptions to the dystrophin reading frame rule are usually resolved after molecular diagnosis on muscle RNA. We report a moderate/severe Becker muscular dystrophy patient with an in-frame genomic deletion of DMD exon 5. This mutation has been reported by others as resulting in Duchenne or Intermediate muscular dystrophy, and the loss of this in-frame exon in one patient led to multiple splicing events, including omission of exon 6, that disrupts the open reading frame and is consistent with a severe phenotype. The patient described has a deletion of dystrophin exon 5 that does not compromise recognition of exon 6, and although the deletion does not disrupt the reading frame, his clinical presentation is more severe than would be expected for classical Becker muscular dystrophy. We suggest that the dystrophin isoform lacking the actin-binding sequence encoded by exon 5 is compromised, reflected by the phenotype resulting from induction of this dystrophin isoform in mouse muscle in vivo. Hence, exon skipping to address DMD-causing mutations within DMD exon 5 may not yield an isoform that confers marked clinical benefit. Additional studies will be required to determine whether multi-exon skipping strategies could yield more functional dystrophin isoforms, since some BMD patients with larger in-frame deletions in this region have been reported with mild phenotypes.
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Affiliation(s)
- Zhi Yon Charles Toh
- Western Australian Neuroscience Research Institute, Perth, Australia
- University of Western Australia, Perth, Australia
| | | | - Gavin Pinniger
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth, Australia
| | - Abbie M. Adams
- Western Australian Neuroscience Research Institute, Perth, Australia
- University of Western Australia, Perth, Australia
- Centre for Comparative Genomics, Murdoch University, Perth, Australia
| | | | - Brenda L. Wong
- Department of Paediatrics, Department of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Sue Fletcher
- Western Australian Neuroscience Research Institute, Perth, Australia
- University of Western Australia, Perth, Australia
- Centre for Comparative Genomics, Murdoch University, Perth, Australia
| | - Steve D. Wilton
- Western Australian Neuroscience Research Institute, Perth, Australia
- University of Western Australia, Perth, Australia
- Centre for Comparative Genomics, Murdoch University, Perth, Australia
- * E-mail:
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Stirnweiss A, McCarthy K, Oommen J, Crook ML, Hardy K, Kees UR, Wilton SD, Anazodo A, Beesley AH. A novel BRD4-NUT fusion in an undifferentiated sinonasal tumor highlights alternative splicing as a contributing oncogenic factor in NUT midline carcinoma. Oncogenesis 2015; 4:e174. [PMID: 26551281 PMCID: PMC4670959 DOI: 10.1038/oncsis.2015.33] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 09/22/2015] [Indexed: 12/22/2022] Open
Abstract
NUT midline carcinoma (NMC) is a fatal cancer that arises in various tissues along the upper midline of the body. The defining molecular feature of NMC is a chromosomal translocation that joins (in the majority of cases) the nuclear testis gene NUT (NUTM1) to the bromodomain protein family member 4 (BRD4) and thereby creating a fusion oncogene that disrupts cellular differentiation and drives the disease. In this study, we report the case of an adolescent NMC patient presenting with severe facial pain, proptosis and visual impairment due to a mass arising from the ethmoid sinus that invaded the right orbit and frontal lobe. Treatment involved radical resection, including exenteration of the affected eye with the view to consolidate treatment with radiation therapy; however, the patient experienced rapid tumor progression and passed away 79 days post resection. Molecular analysis of the tumor tissue identified a novel in-frame BRD4-NUT transcript, with BRD4 exon 15 fused to the last 124 nucleotides of NUT exon 2 (BRD4-NUT ex15:ex2Δnt1–585). The partial deletion of NUT exon 2 was attributed to a mid-exonic genomic breakpoint and the subsequent activation of a cryptic splice site further downstream within the exon. Inhibition of the canonical 3′ acceptor splice site of NUT intron 1 in cell lines expressing the most common NMC fusion transcripts (PER-403, BRD4-NUT ex11:ex2; PER-624, BRD4-NUT ex15:ex2) induced alternative splicing from the same cryptic splice site as identified in the patient. Detection of low levels of an in-frame BRD4-NUT ex11:ex2Δnt1–585 transcript in PER-403 confirmed endogenous splicing from this alternative exon 2 splice site. Although further studies are necessary to assess the clinical relevance of the increasing number of variant fusions described in NMC, the findings presented in this case identify alternative splicing as a mechanism that contributes to this pathogenic complexity.
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Affiliation(s)
- A Stirnweiss
- Division of Children's Leukaemia and Cancer Research, Telethon Kids Institute, The University of Western Australia, West Perth, WA, Australia
| | - K McCarthy
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW, Australia
| | - J Oommen
- Division of Children's Leukaemia and Cancer Research, Telethon Kids Institute, The University of Western Australia, West Perth, WA, Australia
| | - M L Crook
- Department of Pathology, Princess Margaret Hospital for Children, Perth, WA, Australia
| | - K Hardy
- Cyto Labs Pty Ltd, Perth, WA, Australia
| | - U R Kees
- Division of Children's Leukaemia and Cancer Research, Telethon Kids Institute, The University of Western Australia, West Perth, WA, Australia
| | - S D Wilton
- Molecular Therapy Laboratory, Western Australian Neuroscience Research Institute, Centre for Comparative Genomics, Murdoch University, Perth, WA, Australia
| | - A Anazodo
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW, Australia.,Prince of Wales Hospital, Randwick, NSW, Australia
| | - A H Beesley
- Division of Children's Leukaemia and Cancer Research, Telethon Kids Institute, The University of Western Australia, West Perth, WA, Australia
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de la Kethulle de Ryhove L, Ansseau E, Nachtegael C, Pieters K, Vanderplanck C, Geens M, Sermon K, Wilton SD, Coppée F, Lagneaux L, Belayew A. The Role of D4Z4-Encoded Proteins in the Osteogenic Differentiation of Mesenchymal Stromal Cells Isolated from Bone Marrow. Stem Cells Dev 2015; 24:2674-86. [PMID: 26192274 DOI: 10.1089/scd.2014.0575] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is associated with an activation of the double homeobox 4 (DUX4) gene, which we previously identified within the D4Z4 repeated elements in the 4q35 subtelomeric region. The pathological DUX4 mRNA is derived from the most distal D4Z4 unit and extends unexpectedly within the flanking pLAM region, which provides an intron and polyadenylation signal. The conditions that are required to develop FSHD are a permissive allele providing the polyadenylation signal and hypomethylation of the D4Z4 repeat array compared with the healthy muscle. The DUX4 protein is a 52-kDa transcription factor that initiates a large gene deregulation cascade leading to muscle atrophy, inflammation, differentiation defects, and oxidative stress, which are the key features of FSHD. DUX4 is a retrogene that is normally expressed in germline cells and is submitted to repeat-induced silencing in adult tissues. Since DUX4 mRNAs have been detected in human embryonic and induced pluripotent stem cells, we investigated whether they could also be expressed in human mesenchymal stromal cells (hMSCs). We found that DUX4 mRNAs were induced during the differentiation of hMSCs into osteoblasts and that this process involved DUX4 and new longer protein forms (58 and 70 kDa). A DUX4 mRNA with a more distant 5' start site was characterized that presented a 60-codon reading frame extension and encoded the 58-kDa protein. Transfections of hMSCs with an antisense oligonucleotide targeting DUX4 mRNAs decreased both the 52- and 58-kDa protein levels and confirmed their identity. Gain- and loss-of-function experiments in hMSCs suggested these DUX4 proteins had opposite roles in osteogenic differentiation as evidenced by the alkaline phosphatase activity and calcium deposition. Differentiation was delayed by the 58-kDa DUX4 expression and it was increased by 52-kDa DUX4. These data indicate a role for DUX4 protein forms in the osteogenic differentiation of hMSCs.
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Affiliation(s)
| | - Eugénie Ansseau
- 1 Laboratory of Molecular Biology, University of Mons , Mons, Belgium
| | | | - Karlien Pieters
- 2 Laboratory of Clinical Cell Therapy, Institut Jules Bordet, Université Libre de Bruxelles , Brussels, Belgium
| | | | - Mieke Geens
- 3 Department of Embryology and Genetics, Vrije Universiteit Brussel , Jette, Belgium
| | - Karen Sermon
- 3 Department of Embryology and Genetics, Vrije Universiteit Brussel , Jette, Belgium
| | - Steve D Wilton
- 4 Centre for Comparative Genomics, Murdoch University , Murdoch, and The University of Western Australia, Crawley, and Western Australian Neuroscience Institute, Nedlands, Western Australia, Australia
| | - Frédérique Coppée
- 1 Laboratory of Molecular Biology, University of Mons , Mons, Belgium
| | - Laurence Lagneaux
- 2 Laboratory of Clinical Cell Therapy, Institut Jules Bordet, Université Libre de Bruxelles , Brussels, Belgium
| | - Alexandra Belayew
- 1 Laboratory of Molecular Biology, University of Mons , Mons, Belgium
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