1
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Signoria I, Zwartkruis MM, Geerlofs L, Perenthaler E, Faller KM, James R, McHale-Owen H, Green JW, Kortooms J, Snellen SH, Asselman FL, Gillingwater TH, Viero G, Wadman RI, van der Pol WL, Groen EJ. Patient-specific responses to SMN2 splice-modifying treatments in spinal muscular atrophy fibroblasts. Mol Ther Methods Clin Dev 2024; 32:101379. [PMID: 39655308 PMCID: PMC11626024 DOI: 10.1016/j.omtm.2024.101379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2024] [Accepted: 11/08/2024] [Indexed: 12/12/2024]
Abstract
The availability of three therapies for the neuromuscular disease spinal muscular atrophy (SMA) highlights the need to match patients to the optimal treatment. Two of these treatments (nusinersen and risdiplam) target splicing of SMN2, but treatment outcomes vary from patient to patient. An incomplete understanding of the complex interactions among SMA genetics, SMN protein and mRNA levels, and gene-targeting treatments, limits our ability to explain this variability and identify optimal treatment strategies for individual patients. To address this, we analyzed responses to nusinersen and risdiplam in 45 primary fibroblast cell lines. Pre-treatment SMN2-FL, SMN2Δ7 mRNA, and SMN protein levels were influenced by SMN2 copy number, age, and sex. After treatment, SMN and mRNA levels were more heterogeneous. In 43% of patients, response to both therapies was similar, but in 57% one treatment led to a significantly higher SMN increase than the other treatment. Younger age, higher SMN2 copy number, and higher SMN levels before treatment predicted better in vitro efficacy. These findings showcase patient-derived fibroblasts as a tool for identifying molecular predictors for personalized treatment.
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Affiliation(s)
- Ilaria Signoria
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Maria M. Zwartkruis
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Lotte Geerlofs
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | | | - Kiterie M.E. Faller
- Edinburgh Medical School: Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - Rachel James
- Edinburgh Medical School: Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, Edinburgh, UK
| | - Harriet McHale-Owen
- Edinburgh Medical School: Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, Edinburgh, UK
| | - Jared W. Green
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Joris Kortooms
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Sophie H. Snellen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Fay-Lynn Asselman
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Thomas H. Gillingwater
- Edinburgh Medical School: Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, Edinburgh, UK
| | | | - Renske I. Wadman
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Ewout J.N. Groen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
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2
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Cantara S, Simoncelli G, Ricci C. Antisense Oligonucleotides (ASOs) in Motor Neuron Diseases: A Road to Cure in Light and Shade. Int J Mol Sci 2024; 25:4809. [PMID: 38732027 PMCID: PMC11083842 DOI: 10.3390/ijms25094809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/23/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
Antisense oligonucleotides (ASOs) are short oligodeoxynucleotides designed to bind to specific regions of target mRNA. ASOs can modulate pre-mRNA splicing, increase levels of functional proteins, and decrease levels of toxic proteins. ASOs are being developed for the treatment of motor neuron diseases (MNDs), including spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS) and spinal and bulbar muscular atrophy (SBMA). The biggest success has been the ASO known as nusinersen, the first effective therapy for SMA, able to improve symptoms and slow disease progression. Another success is tofersen, an ASO designed to treat ALS patients with SOD1 gene mutations. Both ASOs have been approved by the FDA and EMA. On the other hand, ASO treatment in ALS patients with the C9orf72 gene mutation did not show any improvement in disease progression. The aim of this review is to provide an up-to-date overview of ASO research in MNDs, from preclinical studies to clinical trials and, where available, regulatory approval. We highlight the successes and failures, underline the strengths and limitations of the current ASO research, and suggest possible approaches that could lead to more effective treatments.
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Affiliation(s)
- Silvia Cantara
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy;
| | - Giorgia Simoncelli
- Unit of Neurology and Clinical Neurophysiology, Department of Neurological and Motor Sciences, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy;
| | - Claudia Ricci
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy;
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3
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Dai S, Qiu L, Veeraraghavan VP, Sheu CL, Mony U. Advances in iPSC Technology in Neural Disease Modeling, Drug Screening, and Therapy. Curr Stem Cell Res Ther 2024; 19:809-819. [PMID: 37291782 DOI: 10.2174/1574888x18666230608105703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/16/2023] [Accepted: 05/11/2023] [Indexed: 06/10/2023]
Abstract
Neurodegenerative disorders (NDs) including Alzheimer's Disease, Parkinson's Disease, Amyotrophic Lateral Sclerosis (ALS), and Huntington's disease are all incurable and can only be managed with drugs for the associated symptoms. Animal models of human illnesses help to advance our understanding of the pathogenic processes of diseases. Understanding the pathogenesis as well as drug screening using appropriate disease models of neurodegenerative diseases (NDs) are vital for identifying novel therapies. Human-derived induced pluripotent stem cell (iPSC) models can be an efficient model to create disease in a dish and thereby can proceed with drug screening and identifying appropriate drugs. This technology has many benefits, including efficient reprogramming and regeneration potential, multidirectional differentiation, and the lack of ethical concerns, which open up new avenues for studying neurological illnesses in greater depth. The review mainly focuses on the use of iPSC technology in neuronal disease modeling, drug screening, and cell therapy.
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Affiliation(s)
- Sihan Dai
- Department of Biomedical Engineering, Shantou University, Shantou, 515063, China
| | - Linhui Qiu
- Department of Biomedical Engineering, Shantou University, Shantou, 515063, China
| | - Vishnu Priya Veeraraghavan
- Centre of Molecular Medicine and Diagnostics (COMManD), Department of Biochemistry, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, 600077, India
| | - Chia-Lin Sheu
- Department of Biomedical Engineering, Shantou University, Shantou, 515063, China
| | - Ullas Mony
- Centre of Molecular Medicine and Diagnostics (COMManD), Department of Biochemistry, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, 600077, India
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4
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Amanat M, Nemeth CL, Fine AS, Leung DG, Fatemi A. Antisense Oligonucleotide Therapy for the Nervous System: From Bench to Bedside with Emphasis on Pediatric Neurology. Pharmaceutics 2022; 14:2389. [PMID: 36365206 PMCID: PMC9695718 DOI: 10.3390/pharmaceutics14112389] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/26/2022] [Accepted: 11/02/2022] [Indexed: 09/05/2023] Open
Abstract
Antisense oligonucleotides (ASOs) are disease-modifying agents affecting protein-coding and noncoding ribonucleic acids. Depending on the chemical modification and the location of hybridization, ASOs are able to reduce the level of toxic proteins, increase the level of functional protein, or modify the structure of impaired protein to improve function. There are multiple challenges in delivering ASOs to their site of action. Chemical modifications in the phosphodiester bond, nucleotide sugar, and nucleobase can increase structural thermodynamic stability and prevent ASO degradation. Furthermore, different particles, including viral vectors, conjugated peptides, conjugated antibodies, and nanocarriers, may improve ASO delivery. To date, six ASOs have been approved by the US Food and Drug Administration (FDA) in three neurological disorders: spinal muscular atrophy, Duchenne muscular dystrophy, and polyneuropathy caused by hereditary transthyretin amyloidosis. Ongoing preclinical and clinical studies are assessing the safety and efficacy of ASOs in multiple genetic and acquired neurological conditions. The current review provides an update on underlying mechanisms, design, chemical modifications, and delivery of ASOs. The administration of FDA-approved ASOs in neurological disorders is described, and current evidence on the safety and efficacy of ASOs in other neurological conditions, including pediatric neurological disorders, is reviewed.
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Affiliation(s)
- Man Amanat
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christina L. Nemeth
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amena Smith Fine
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Doris G. Leung
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Center for Genetic Muscle Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Ali Fatemi
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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5
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Rescue of a familial dysautonomia mouse model by AAV9-Exon-specific U1 snRNA. Am J Hum Genet 2022; 109:1534-1548. [PMID: 35905737 PMCID: PMC9388384 DOI: 10.1016/j.ajhg.2022.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/30/2022] [Indexed: 02/06/2023] Open
Abstract
Familial dysautonomia (FD) is a currently untreatable, neurodegenerative disease caused by a splicing mutation (c.2204+6T>C) that causes skipping of exon 20 of the elongator complex protein 1 (ELP1) pre-mRNA. Here, we used adeno-associated virus serotype 9 (AAV9-U1-FD) to deliver an exon-specific U1 (ExSpeU1) small nuclear RNA, designed to cause inclusion of ELP1 exon 20 only in those cells expressing the target pre-mRNA, in a phenotypic mouse model of FD. Postnatal systemic and intracerebral ventricular treatment in these mice increased the inclusion of ELP1 exon 20. This also augmented the production of functional protein in several tissues including brain, dorsal root, and trigeminal ganglia. Crucially, the treatment rescued most of the FD mouse mortality before one month of age (89% vs 52%). There were notable improvements in ataxic gait as well as renal (serum creatinine) and cardiac (ejection fraction) functions. RNA-seq analyses of dorsal root ganglia from treated mice and human cells overexpressing FD-ExSpeU1 revealed only minimal global changes in gene expression and splicing. Overall then, our data prove that AAV9-U1-FD is highly specific and will likely be a safe and effective therapeutic strategy for this debilitating disease.
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6
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Lange J, Zhou H, McTague A. Cerebral Organoids and Antisense Oligonucleotide Therapeutics: Challenges and Opportunities. Front Mol Neurosci 2022; 15:941528. [PMID: 35836547 PMCID: PMC9274522 DOI: 10.3389/fnmol.2022.941528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/09/2022] [Indexed: 11/18/2022] Open
Abstract
The advent of stem cell-derived cerebral organoids has already advanced our understanding of disease mechanisms in neurological diseases. Despite this, many remain without effective treatments, resulting in significant personal and societal health burden. Antisense oligonucleotides (ASOs) are one of the most widely used approaches for targeting RNA and modifying gene expression, with significant advancements in clinical trials for epilepsy, neuromuscular disorders and other neurological conditions. ASOs have further potential to address the unmet need in other neurological diseases for novel therapies which directly target the causative genes, allowing precision treatment. Induced pluripotent stem cell (iPSC) derived cerebral organoids represent an ideal platform in which to evaluate novel ASO therapies. In patient-derived organoids, disease-causing mutations can be studied in the native genetic milieu, opening the door to test personalized ASO therapies and n-of-1 approaches. In addition, CRISPR-Cas9 can be used to generate isogenic iPSCs to assess the effects of ASOs, by either creating disease-specific mutations or correcting available disease iPSC lines. Currently, ASO therapies face a number of challenges to wider translation, including insufficient uptake by distinct and preferential cell types in central nervous system and inability to cross the blood brain barrier necessitating intrathecal administration. Cerebral organoids provide a practical model to address and improve these limitations. In this review we will address the current use of organoids to test ASO therapies, opportunities for future applications and challenges including those inherent to cerebral organoids, issues with organoid transfection and choice of appropriate read-outs.
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Affiliation(s)
- Jenny Lange
- Department for Developmental Neurosciences, Zayed Centre for Research Into Rare Disease in Children, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Haiyan Zhou
- Genetics and Genomic Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, United Kingdom
| | - Amy McTague
- Department for Developmental Neurosciences, Zayed Centre for Research Into Rare Disease in Children, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, United Kingdom
- *Correspondence: Amy McTague,
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7
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Li J, Lim RG, Kaye JA, Dardov V, Coyne AN, Wu J, Milani P, Cheng A, Thompson TG, Ornelas L, Frank A, Adam M, Banuelos MG, Casale M, Cox V, Escalante-Chong R, Daigle JG, Gomez E, Hayes L, Holewenski R, Lei S, Lenail A, Lima L, Mandefro B, Matlock A, Panther L, Patel-Murray NL, Pham J, Ramamoorthy D, Sachs K, Shelley B, Stocksdale J, Trost H, Wilhelm M, Venkatraman V, Wassie BT, Wyman S, Yang S, NYGC ALS Consortium, Van Eyk JE, Lloyd TE, Finkbeiner S, Fraenkel E, Rothstein JD, Sareen D, Svendsen CN, Thompson LM. An integrated multi-omic analysis of iPSC-derived motor neurons from C9ORF72 ALS patients. iScience 2021; 24:103221. [PMID: 34746695 PMCID: PMC8554488 DOI: 10.1016/j.isci.2021.103221] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/29/2021] [Accepted: 09/30/2021] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases are challenging for systems biology because of the lack of reliable animal models or patient samples at early disease stages. Induced pluripotent stem cells (iPSCs) could address these challenges. We investigated DNA, RNA, epigenetics, and proteins in iPSC-derived motor neurons from patients with ALS carrying hexanucleotide expansions in C9ORF72. Using integrative computational methods combining all omics datasets, we identified novel and known dysregulated pathways. We used a C9ORF72 Drosophila model to distinguish pathways contributing to disease phenotypes from compensatory ones and confirmed alterations in some pathways in postmortem spinal cord tissue of patients with ALS. A different differentiation protocol was used to derive a separate set of C9ORF72 and control motor neurons. Many individual -omics differed by protocol, but some core dysregulated pathways were consistent. This strategy of analyzing patient-specific neurons provides disease-related outcomes with small numbers of heterogeneous lines and reduces variation from single-omics to elucidate network-based signatures.
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Affiliation(s)
- Jonathan Li
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ryan G. Lim
- UCI MIND, University of California, Irvine, CA 92697, USA
| | - Julia A. Kaye
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Victoria Dardov
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alyssa N. Coyne
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
- Department of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Jie Wu
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA
| | - Pamela Milani
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Andrew Cheng
- Cellular and Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | | | - Loren Ornelas
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Aaron Frank
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Miriam Adam
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Maria G. Banuelos
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Malcolm Casale
- UCI MIND, University of California, Irvine, CA 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Veerle Cox
- Cellular and Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Renan Escalante-Chong
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - J. Gavin Daigle
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
- Department of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Emilda Gomez
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Lindsey Hayes
- Department of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Ronald Holewenski
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Susan Lei
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Alex Lenail
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Leandro Lima
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Berhan Mandefro
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Andrea Matlock
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Lindsay Panther
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | | | - Jacqueline Pham
- Department of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Divya Ramamoorthy
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Karen Sachs
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Brandon Shelley
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Jennifer Stocksdale
- UCI MIND, University of California, Irvine, CA 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Hannah Trost
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Mark Wilhelm
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Vidya Venkatraman
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Brook T. Wassie
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Stacia Wyman
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, CA 92697, USA
| | - Stephanie Yang
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | | | - Jennifer E. Van Eyk
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Thomas E. Lloyd
- Department of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Steven Finkbeiner
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA
- Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Ernest Fraenkel
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jeffrey D. Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
- Department of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
- Cellular and Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, MA 212056, USA
| | - Dhruv Sareen
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Clive N. Svendsen
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Leslie M. Thompson
- UCI MIND, University of California, Irvine, CA 92697, USA
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA 92697, USA
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, CA 92697, USA
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8
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McTague A, Rossignoli G, Ferrini A, Barral S, Kurian MA. Genome Editing in iPSC-Based Neural Systems: From Disease Models to Future Therapeutic Strategies. Front Genome Ed 2021; 3:630600. [PMID: 34713254 PMCID: PMC8525405 DOI: 10.3389/fgeed.2021.630600] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/19/2021] [Indexed: 12/14/2022] Open
Abstract
Therapeutic advances for neurological disorders are challenging due to limited accessibility of the human central nervous system and incomplete understanding of disease mechanisms. Many neurological diseases lack precision treatments, leading to significant disease burden and poor outcome for affected patients. Induced pluripotent stem cell (iPSC) technology provides human neuronal cells that facilitate disease modeling and development of therapies. The use of genome editing, in particular CRISPR-Cas9 technology, has extended the potential of iPSCs, generating new models for a number of disorders, including Alzheimers and Parkinson Disease. Editing of iPSCs, in particular with CRISPR-Cas9, allows generation of isogenic pairs, which differ only in the disease-causing mutation and share the same genetic background, for assessment of phenotypic differences and downstream effects. Moreover, genome-wide CRISPR screens allow high-throughput interrogation for genetic modifiers in neuronal phenotypes, leading to discovery of novel pathways, and identification of new therapeutic targets. CRISPR-Cas9 has now evolved beyond altering gene expression. Indeed, fusion of a defective Cas9 (dCas9) nuclease with transcriptional repressors or activation domains allows down-regulation or activation of gene expression (CRISPR interference, CRISPRi; CRISPR activation, CRISPRa). These new tools will improve disease modeling and facilitate CRISPR and cell-based therapies, as seen for epilepsy and Duchenne muscular dystrophy. Genome engineering holds huge promise for the future understanding and treatment of neurological disorders, but there are numerous barriers to overcome. The synergy of iPSC-based model systems and gene editing will play a vital role in the route to precision medicine and the clinical translation of genome editing-based therapies.
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Affiliation(s)
- Amy McTague
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom.,Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
| | - Giada Rossignoli
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Arianna Ferrini
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Serena Barral
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Manju A Kurian
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom.,Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
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9
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The Importance of Digging into the Genetics of SMN Genes in the Therapeutic Scenario of Spinal Muscular Atrophy. Int J Mol Sci 2021; 22:ijms22169029. [PMID: 34445733 PMCID: PMC8396600 DOI: 10.3390/ijms22169029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
After 26 years of discovery of the determinant survival motor neuron 1 and the modifier survival motor neuron 2 genes (SMN1 and SMN2, respectively), three SMN-dependent specific therapies are already approved by FDA and EMA and, as a consequence, worldwide SMA patients are currently under clinical investigation and treatment. Bi-allelic pathogenic variants (mostly deletions) in SMN1 should be detected in SMA patients to confirm the disease. Determination of SMN2 copy number has been historically employed to correlate with the phenotype, predict disease evolution, stratify patients for clinical trials and to define those eligible for treatment. In view that discordant genotype-phenotype correlations are present in SMA, besides technical issues with detection of SMN2 copy number, we have hypothesized that copy number determination is only the tip of the iceberg and that more deepen studies of variants, sequencing and structures of the SMN2 genes are necessary for a better understanding of the disease as well as to investigate possible influences in treatment responses. Here, we highlight the importance of a comprehensive approach of SMN1 and SMN2 genetics with the perspective to apply for better prediction of SMA in positive neonatal screening cases and early diagnosis to start treatments.
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10
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Lenaers G, Neutzner A, Le Dantec Y, Jüschke C, Xiao T, Decembrini S, Swirski S, Kieninger S, Agca C, Kim US, Reynier P, Yu-Wai-Man P, Neidhardt J, Wissinger B. Dominant optic atrophy: Culprit mitochondria in the optic nerve. Prog Retin Eye Res 2021; 83:100935. [PMID: 33340656 DOI: 10.1016/j.preteyeres.2020.100935] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Dominant optic atrophy (DOA) is an inherited mitochondrial disease leading to specific degeneration of retinal ganglion cells (RGCs), thus compromising transmission of visual information from the retina to the brain. Usually, DOA starts during childhood and evolves to poor vision or legal blindness, affecting the central vision, whilst sparing the peripheral visual field. In 20% of cases, DOA presents as syndromic disorder, with secondary symptoms affecting neuronal and muscular functions. Twenty years ago, we demonstrated that heterozygous mutations in OPA1 are the most frequent molecular cause of DOA. Since then, variants in additional genes, whose functions in many instances converge with those of OPA1, have been identified by next generation sequencing. OPA1 encodes a dynamin-related GTPase imported into mitochondria and located to the inner membrane and intermembrane space. The many OPA1 isoforms, resulting from alternative splicing of three exons, form complex homopolymers that structure mitochondrial cristae, and contribute to fusion of the outer membrane, thus shaping the whole mitochondrial network. Moreover, OPA1 is required for oxidative phosphorylation, maintenance of mitochondrial genome, calcium homeostasis and regulation of apoptosis, thus making OPA1 the Swiss army-knife of mitochondria. Understanding DOA pathophysiology requires the understanding of RGC peculiarities with respect to OPA1 functions. Besides the tremendous energy requirements of RGCs to relay visual information from the eye to the brain, these neurons present unique features related to their differential environments in the retina, and to the anatomical transition occurring at the lamina cribrosa, which parallel major adaptations of mitochondrial physiology and shape, in the pre- and post-laminar segments of the optic nerve. Three DOA mouse models, with different Opa1 mutations, have been generated to study intrinsic mechanisms responsible for RGC degeneration, and these have further revealed secondary symptoms related to mitochondrial dysfunctions, mirroring the more severe syndromic phenotypes seen in a subgroup of patients. Metabolomics analyses of cells, mouse organs and patient plasma mutated for OPA1 revealed new unexpected pathophysiological mechanisms related to mitochondrial dysfunction, and biomarkers correlated quantitatively to the severity of the disease. Here, we review and synthesize these data, and propose different approaches for embracing possible therapies to fulfil the unmet clinical needs of this disease, and provide hope to affected DOA patients.
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Affiliation(s)
- Guy Lenaers
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France.
| | - Albert Neutzner
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland.
| | - Yannick Le Dantec
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
| | - Christoph Jüschke
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Ting Xiao
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sarah Decembrini
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland
| | - Sebastian Swirski
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Sinja Kieninger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Cavit Agca
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey; Nanotechnology Research and Application Center (SUNUM), Sabanci University, Istanbul, Turkey
| | - Ungsoo S Kim
- Kim's Eye Hospital, Seoul, South Korea; Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK
| | - Pascal Reynier
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France; Department of Biochemistry, University Hospital of Angers, Angers, France
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - John Neidhardt
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany.
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany.
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Impairment of the neurotrophic signaling hub B-Raf contributes to motoneuron degeneration in spinal muscular atrophy. Proc Natl Acad Sci U S A 2021; 118:2007785118. [PMID: 33931501 DOI: 10.1073/pnas.2007785118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a motoneuron disease caused by deletions of the Survival of Motoneuron 1 gene (SMN1) and low SMN protein levels. SMN restoration is the concept behind a number of recently approved drugs which result in impressive yet limited effects. Since SMN has already been enhanced in treated patients, complementary SMN-independent approaches are needed. Previously, a number of altered signaling pathways which regulate motoneuron degeneration have been identified as candidate targets. However, signaling pathways form networks, and their connectivity is still unknown in SMA. Here, we used presymptomatic SMA mice to elucidate the network of altered signaling in SMA. The SMA network is structured in two clusters with AKT and 14-3-3 ζ/δ in their centers. Both clusters are connected by B-Raf as a major signaling hub. The direct interaction of B-Raf with 14-3-3 ζ/δ is important for an efficient neurotrophic activation of the MEK/ERK pathway and crucial for motoneuron survival. Further analyses in SMA mice revealed that both proteins were down-regulated in motoneurons and the spinal cord with B-Raf being reduced at presymptomatic stages. Primary fibroblasts and iPSC-derived motoneurons from SMA patients both showed the same pattern of down-regulation. This mechanism is conserved across species since a Caenorhabditis elegans SMA model showed less expression of the B-Raf homolog lin-45 Accordingly, motoneuron survival was rescued by a cell autonomous lin-45 expression in a C. elegans SMA model resulting in improved motor functions. This rescue was effective even after the onset of motoneuron degeneration and mediated by the MEK/ERK pathway.
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12
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Cappella M, Elouej S, Biferi MG. The Potential of Induced Pluripotent Stem Cells to Test Gene Therapy Approaches for Neuromuscular and Motor Neuron Disorders. Front Cell Dev Biol 2021; 9:662837. [PMID: 33937264 PMCID: PMC8080375 DOI: 10.3389/fcell.2021.662837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/22/2021] [Indexed: 12/11/2022] Open
Abstract
The reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) represents a major advance for the development of human disease models. The emerging of this technique fostered the concept of "disease in a dish," which consists into the generation of patient-specific models in vitro. Currently, iPSCs are used to study pathological molecular mechanisms caused by genetic mutations and they are considered a reliable model for high-throughput drug screenings. Importantly, precision-medicine approaches to treat monogenic disorders exploit iPSCs potential for the selection and validation of lead candidates. For example, antisense oligonucleotides (ASOs) were tested with promising results in myoblasts or motor neurons differentiated from iPSCs of patients affected by either Duchenne muscular dystrophy or Amyotrophic lateral sclerosis. However, the use of iPSCs needs additional optimization to ensure translational success of the innovative strategies based on gene delivery through adeno associated viral vectors (AAV) for these diseases. Indeed, to establish an efficient transduction of iPSCs with AAV, several aspects should be optimized, including viral vector serotype, viral concentration and timing of transduction. This review will outline the use of iPSCs as a model for the development and testing of gene therapies for neuromuscular and motor neuron disorders. It will then discuss the advantages for the use of this versatile tool for gene therapy, along with the challenges associated with the viral vector transduction of iPSCs.
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Affiliation(s)
- Marisa Cappella
- Sorbonne University, INSERM, Institute of Myology, Center of Research in Myology, Paris, France
| | - Sahar Elouej
- Sorbonne University, INSERM, Institute of Myology, Center of Research in Myology, Paris, France
| | - Maria Grazia Biferi
- Sorbonne University, INSERM, Institute of Myology, Center of Research in Myology, Paris, France
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13
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Sabitha KR, Shetty AK, Upadhya D. Patient-derived iPSC modeling of rare neurodevelopmental disorders: Molecular pathophysiology and prospective therapies. Neurosci Biobehav Rev 2020; 121:201-219. [PMID: 33370574 DOI: 10.1016/j.neubiorev.2020.12.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 12/12/2022]
Abstract
The pathological alterations that manifest during the early embryonic development due to inherited and acquired factors trigger various neurodevelopmental disorders (NDDs). Besides major NDDs, there are several rare NDDs, exhibiting specific characteristics and varying levels of severity triggered due to genetic and epigenetic anomalies. The rarity of subjects, paucity of neural tissues for detailed analysis, and the unavailability of disease-specific animal models have hampered detailed comprehension of rare NDDs, imposing heightened challenge to the medical and scientific community until a decade ago. The generation of functional neurons and glia through directed differentiation protocols for patient-derived iPSCs, CRISPR/Cas9 technology, and 3D brain organoid models have provided an excellent opportunity and vibrant resource for decoding the etiology of brain development for rare NDDs caused due to monogenic as well as polygenic disorders. The present review identifies cellular and molecular phenotypes demonstrated from patient-derived iPSCs and possible therapeutic opportunities identified for these disorders. New insights to reinforce the existing knowledge of the pathophysiology of these disorders and prospective therapeutic applications are discussed.
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Affiliation(s)
- K R Sabitha
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA.
| | - Dinesh Upadhya
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India.
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14
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Donegà S, Rogalska ME, Pianigiani G, Igreja S, Amaral MD, Pagani F. Rescue of common exon-skipping mutations in cystic fibrosis with modified U1 snRNAs. Hum Mutat 2020; 41:2143-2154. [PMID: 32935393 DOI: 10.1002/humu.24116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/31/2020] [Accepted: 09/07/2020] [Indexed: 01/22/2023]
Abstract
In cystic fibrosis (CF), the correction of splicing defects represents an interesting therapeutic approach to restore normal CFTR function. In this study, we focused on 10 common mutations/variants 711+3A>G/C, 711+5G>A, TG13T3, TG13T5, TG12T5, 1863C>T, 1898+3A>G, 2789+5G>A, and 3120G>A that induce skipping of the corresponding CFTR exons 5, 10, 13, 16, and 18. To rescue the splicing defects we tested, in a minigene assay, a panel of modified U1 small nuclear RNAs (snRNAs), named Exon Specific U1s (ExSpeU1s), that was engineered to bind to intronic sequences downstream of each defective exon. Using this approach, we show that all 10 splicing mutations analyzed are efficiently corrected by specific ExSpeU1s. Using complementary DNA-splicing competent minigenes, we also show that the ExspeU1-mediated splicing correction at the RNA level recovered the full-length CFTR protein for 1863C>T, 1898+3A>G, 2789+5G>A variants. In addition, detailed mutagenesis experiments performed on exon 13 led us to identify a novel intronic regulatory element involved in the ExSpeU1-mediated splicing rescue. These results provide a common strategy based on modified U1 snRNAs to correct exon skipping in a group of disease-causing CFTR mutations.
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Affiliation(s)
- Stefano Donegà
- Human Molecular Genetics, ICGEB - International Center for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Malgorzata Ewa Rogalska
- Human Molecular Genetics, ICGEB - International Center for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Giulia Pianigiani
- Human Molecular Genetics, ICGEB - International Center for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Susana Igreja
- BioISI - Biosystems and Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Margarida Duarte Amaral
- BioISI - Biosystems and Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Franco Pagani
- Human Molecular Genetics, ICGEB - International Center for Genetic Engineering and Biotechnology, Trieste, Italy
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Adami R, Bottai D. Spinal Muscular Atrophy Modeling and Treatment Advances by Induced Pluripotent Stem Cells Studies. Stem Cell Rev Rep 2020; 15:795-813. [PMID: 31863335 DOI: 10.1007/s12015-019-09910-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Spinal Muscular Atrophy (SMA) is a neurodegenerative disease characterized by specific and predominantly lower motor neuron (MN) loss. SMA is the main reason for infant death, while about one in 40 children born is a healthy carrier. SMA is caused by decreased levels of production of a ubiquitously expressed gene: the survival motor neuron (SMN). All SMA patients present mutations of the telomeric SMN1 gene, but many copies of a centromeric, partially functional paralog gene, SMN2, can somewhat compensate for the SMN1 deficiency, scaling inversely with phenotypic harshness. Because the study of neural tissue in and from patients presents too many challenges and is very often not feasible; the use of animal models, such as the mouse, had a pivotal impact in our understanding of SMA pathology but could not portray totally satisfactorily the elaborate regulatory mechanisms that are present in higher animals, particularly in humans. And while recent therapeutic achievements have been substantial, especially for very young infants, some issues should be considered for the treatment of older patients. An alternative way to study SMA, and other neurological pathologies, is the use of induced pluripotent stem cells (iPSCs) derived from patients. In this work, we will present a wide analysis of the uses of iPSCs in SMA pathology, starting from basic science to their possible roles as therapeutic tools.
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Affiliation(s)
- Raffaella Adami
- Department of Health Sciences, University of Milan, via A. di Rudinì 8, 20142, Milan, Italy
| | - Daniele Bottai
- Department of Health Sciences, University of Milan, via A. di Rudinì 8, 20142, Milan, Italy.
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16
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Nizzardo M, Taiana M, Rizzo F, Aguila Benitez J, Nijssen J, Allodi I, Melzi V, Bresolin N, Comi GP, Hedlund E, Corti S. Synaptotagmin 13 is neuroprotective across motor neuron diseases. Acta Neuropathol 2020; 139:837-853. [PMID: 32065260 PMCID: PMC7181443 DOI: 10.1007/s00401-020-02133-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 12/13/2022]
Abstract
In amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), spinal and lower brainstem motor neurons degenerate, but some motor neuron subtypes are spared, including oculomotor neurons (OMNs). The mechanisms responsible for this selective degeneration are largely unknown, but the molecular signatures of resistant and vulnerable motor neurons are distinct and offer clues to neuronal resilience and susceptibility. Here, we demonstrate that healthy OMNs preferentially express Synaptotagmin 13 (SYT13) compared to spinal motor neurons. In end-stage ALS patients, SYT13 is enriched in both OMNs and the remaining relatively resilient spinal motor neurons compared to controls. Overexpression of SYT13 in ALS and SMA patient motor neurons in vitro improves their survival and increases axon lengths. Gene therapy with Syt13 prolongs the lifespan of ALS mice by 14% and SMA mice by 50% by preserving motor neurons and delaying muscle denervation. SYT13 decreases endoplasmic reticulum stress and apoptosis of motor neurons, both in vitro and in vivo. Thus, SYT13 is a resilience factor that can protect motor neurons and a candidate therapeutic target across motor neuron diseases.
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17
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Donadon I, Bussani E, Riccardi F, Licastro D, Romano G, Pianigiani G, Pinotti M, Konstantinova P, Evers M, Lin S, Rüegg MA, Pagani F. Rescue of spinal muscular atrophy mouse models with AAV9-Exon-specific U1 snRNA. Nucleic Acids Res 2019; 47:7618-7632. [PMID: 31127278 PMCID: PMC6698663 DOI: 10.1093/nar/gkz469] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/10/2019] [Accepted: 05/16/2019] [Indexed: 12/12/2022] Open
Abstract
Spinal Muscular Atrophy results from loss-of-function mutations in SMN1 but correcting aberrant splicing of SMN2 offers hope of a cure. However, current splice therapy requires repeated infusions and is expensive. We previously rescued SMA mice by promoting the inclusion of a defective exon in SMN2 with germline expression of Exon-Specific U1 snRNAs (ExspeU1). Here we tested viral delivery of SMN2 ExspeU1s encoded by adeno-associated virus AAV9. Strikingly the virus increased SMN2 exon 7 inclusion and SMN protein levels and rescued the phenotype of mild and severe SMA mice. In the severe mouse, the treatment improved the neuromuscular function and increased the life span from 10 to 219 days. ExspeU1 expression persisted for 1 month and was effective at around one five-hundredth of the concentration of the endogenous U1snRNA. RNA-seq analysis revealed our potential drug rescues aberrant SMA expression and splicing profiles, which are mostly related to DNA damage, cell-cycle control and acute phase response. Vastly overexpressing ExspeU1 more than 100-fold above the therapeutic level in human cells did not significantly alter global gene expression or splicing. These results indicate that AAV-mediated delivery of a modified U1snRNP particle may be a novel therapeutic option against SMA.
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Affiliation(s)
- Irving Donadon
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Erica Bussani
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Federico Riccardi
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Danilo Licastro
- CBM S.c.r.l., Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Giulia Romano
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Giulia Pianigiani
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
| | - Pavlina Konstantinova
- Department of Research & Development, uniQure biopharma B.V., Amsterdam, The Netherlands
| | - Melvin Evers
- Department of Research & Development, uniQure biopharma B.V., Amsterdam, The Netherlands
| | - Shuo Lin
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
| | - Markus A Rüegg
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
| | - Franco Pagani
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
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Coutinho MF, Matos L, Santos JI, Alves S. RNA Therapeutics: How Far Have We Gone? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1157:133-177. [PMID: 31342441 DOI: 10.1007/978-3-030-19966-1_7] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In recent years, the RNA molecule became one of the most promising targets for therapeutic intervention. Currently, a large number of RNA-based therapeutics are being investigated both at the basic research level and in late-stage clinical trials. Some of them are even already approved for treatment. RNA-based approaches can act at pre-mRNA level (by splicing modulation/correction using antisense oligonucleotides or U1snRNA vectors), at mRNA level (inhibiting gene expression by siRNAs and antisense oligonucleotides) or at DNA level (by editing mutated sequences through the use of CRISPR/Cas). Other RNA approaches include the delivery of in vitro transcribed (IVT) mRNA or the use of oligonucleotides aptamers. Here we review these approaches and their translation into clinics trying to give a brief overview also on the difficulties to its application as well as the research that is being done to overcome them.
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Affiliation(s)
- Maria Francisca Coutinho
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal
| | - Liliana Matos
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal
| | - Juliana Inês Santos
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal
| | - Sandra Alves
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal.
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Balestra D, Branchini A. Molecular Mechanisms and Determinants of Innovative Correction Approaches in Coagulation Factor Deficiencies. Int J Mol Sci 2019; 20:ijms20123036. [PMID: 31234407 PMCID: PMC6627357 DOI: 10.3390/ijms20123036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/07/2019] [Accepted: 06/18/2019] [Indexed: 02/07/2023] Open
Abstract
Molecular strategies tailored to promote/correct the expression and/or processing of defective coagulation factors would represent innovative therapeutic approaches beyond standard substitutive therapy. Here, we focus on the molecular mechanisms and determinants underlying innovative approaches acting at DNA, mRNA and protein levels in inherited coagulation factor deficiencies, and in particular on: (i) gene editing approaches, which have permitted intervention at the DNA level through the specific recognition, cleavage, repair/correction or activation of target sequences, even in mutated gene contexts; (ii) the rescue of altered pre-mRNA processing through the engineering of key spliceosome components able to promote correct exon recognition and, in turn, the synthesis and secretion of functional factors, as well as the effects on the splicing of missense changes affecting exonic splicing elements; this section includes antisense oligonucleotide- or siRNA-mediated approaches to down-regulate target genes; (iii) the rescue of protein synthesis/function through the induction of ribosome readthrough targeting nonsense variants or the correction of folding defects caused by amino acid substitutions. Overall, these approaches have shown the ability to rescue the expression and/or function of potentially therapeutic levels of coagulation factors in different disease models, thus supporting further studies in the future aimed at evaluating the clinical translatability of these new strategies.
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Affiliation(s)
- Dario Balestra
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy.
| | - Alessio Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy.
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20
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Pacitti D, Privolizzi R, Bax BE. Organs to Cells and Cells to Organoids: The Evolution of in vitro Central Nervous System Modelling. Front Cell Neurosci 2019; 13:129. [PMID: 31024259 PMCID: PMC6465581 DOI: 10.3389/fncel.2019.00129] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/14/2019] [Indexed: 02/05/2023] Open
Abstract
With 100 billion neurons and 100 trillion synapses, the human brain is not just the most complex organ in the human body, but has also been described as "the most complex thing in the universe." The limited availability of human living brain tissue for the study of neurogenesis, neural processes and neurological disorders has resulted in more than a century-long strive from researchers worldwide to model the central nervous system (CNS) and dissect both its striking physiology and enigmatic pathophysiology. The invaluable knowledge gained with the use of animal models and post mortem human tissue remains limited to cross-species similarities and structural features, respectively. The advent of human induced pluripotent stem cell (hiPSC) and 3-D organoid technologies has revolutionised the approach to the study of human brain and CNS in vitro, presenting great potential for disease modelling and translational adoption in drug screening and regenerative medicine, also contributing beneficially to clinical research. We have surveyed more than 100 years of research in CNS modelling and provide in this review an historical excursus of its evolution, from early neural tissue explants and organotypic cultures, to 2-D patient-derived cell monolayers, to the latest development of 3-D cerebral organoids. We have generated a comprehensive summary of CNS modelling techniques and approaches, protocol refinements throughout the course of decades and developments in the study of specific neuropathologies. Current limitations and caveats such as clonal variation, developmental stage, validation of pluripotency and chromosomal stability, functional assessment, reproducibility, accuracy and scalability of these models are also discussed.
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Affiliation(s)
- Dario Pacitti
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London, United Kingdom
- College of Medicine and Health, St Luke’s Campus, University of Exeter, Exeter, United Kingdom
| | - Riccardo Privolizzi
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, London, United Kingdom
| | - Bridget E. Bax
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London, United Kingdom
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21
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Son HW, Yokota T. Recent Advances and Clinical Applications of Exon Inclusion for Spinal Muscular Atrophy. Methods Mol Biol 2019; 1828:57-68. [PMID: 30171534 DOI: 10.1007/978-1-4939-8651-4_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by a mutation in SMN1 that stops production of SMN (survival of motor neuron) protein. Insufficient levels of SMN results in the loss of motor neurons, which causes muscle weakness, respiratory distress, and paralysis. A nearly identical gene (SMN2) contains a C-to-T transition which excludes exon 7 from 90% of the mature mRNA transcripts, leading to unstable proteins which are targeted for degradation. Although SMN2 cannot fully compensate for a loss of SMN1 due to only 10% functional mRNA produced, the discovery of the intronic splicing silencer (ISS-N1) opened a doorway for therapy. By blocking its function with antisense oligonucleotides manipulated for high specificity and efficiency, exon 7 can be included to produce full-length mRNA, which then compensates for the loss of SMN1. Nusinersen (Spinraza), the first FDA-approved antisense oligonucleotide drug targeting SMA, was designed based on this concept and clinical studies have demonstrated a dramatic improvement in patients. Novel chemistries including phosphorodiamidate morpholino oligomers (PMOs) and locked nucleic acids (LNAs), as well as peptide conjugates such as Pip that facilitate accurate targeting to the central nervous system, are explored to increase the efficiency of exon 7 inclusion in the appropriate tissues to ameliorate the SMA phenotype. Due to the rapid advancement of treatments for SMA following the discovery of ISS-N1, the future of SMA treatment is highly promising.
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Affiliation(s)
- Hae-Won Son
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada. .,The Friends of Garrett Cumming Research and Muscular Dystrophy Canada HM Toupin Neurological Science Research Chair, Edmonton, AB, Canada.
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22
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Rizzo F, Nizzardo M, Vashisht S, Molteni E, Melzi V, Taiana M, Salani S, Santonicola P, Di Schiavi E, Bucchia M, Bordoni A, Faravelli I, Bresolin N, Comi GP, Pozzoli U, Corti S. Key role of SMN/SYNCRIP and RNA-Motif 7 in spinal muscular atrophy: RNA-Seq and motif analysis of human motor neurons. Brain 2019; 142:276-294. [PMID: 30649277 PMCID: PMC6351774 DOI: 10.1093/brain/awy330] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 10/23/2018] [Accepted: 11/03/2018] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy is a motor neuron disorder caused by mutations in SMN1. The reasons for the selective vulnerability of motor neurons linked to SMN (encoded by SMN1) reduction remain unclear. Therefore, we performed deep RNA sequencing on human spinal muscular atrophy motor neurons to detect specific altered gene splicing/expression and to identify the presence of a common sequence motif in these genes. Many deregulated genes, such as the neurexin and synaptotagmin families, are implicated in critical motor neuron functions. Motif-enrichment analyses of differentially expressed/spliced genes, including neurexin2 (NRXN2), revealed a common motif, motif 7, which is a target of SYNCRIP. Interestingly, SYNCRIP interacts only with full-length SMN, binding and modulating several motor neuron transcripts, including SMN itself. SYNCRIP overexpression rescued spinal muscular atrophy motor neurons, due to the subsequent increase in SMN and their downstream target NRXN2 through a positive loop mechanism and ameliorated SMN-loss-related pathological phenotypes in Caenorhabditis elegans and mouse models. SMN/SYNCRIP complex through motif 7 may account for selective motor neuron degeneration and represent a potential therapeutic target.
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Affiliation(s)
- Federica Rizzo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Monica Nizzardo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Shikha Vashisht
- Scientific Institute IRCCS E. MEDEA, Computational Biology, Bosisio Parini, Lecco, Italy
| | - Erika Molteni
- Scientific Institute IRCCS E. MEDEA, Computational Biology, Bosisio Parini, Lecco, Italy
| | - Valentina Melzi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Michela Taiana
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Sabrina Salani
- Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Elia Di Schiavi
- Institute of Bioscience and BioResources, IBBR, CNR, Naples, Italy
| | - Monica Bucchia
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Andreina Bordoni
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Irene Faravelli
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
- Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
- Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Uberto Pozzoli
- Scientific Institute IRCCS E. MEDEA, Computational Biology, Bosisio Parini, Lecco, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
- Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
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23
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Montes M, Sanford BL, Comiskey DF, Chandler DS. RNA Splicing and Disease: Animal Models to Therapies. Trends Genet 2019; 35:68-87. [PMID: 30466729 PMCID: PMC6339821 DOI: 10.1016/j.tig.2018.10.002] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 10/01/2018] [Accepted: 10/16/2018] [Indexed: 02/07/2023]
Abstract
Alternative splicing of pre-mRNA increases genetic diversity, and recent studies estimate that most human multiexon genes are alternatively spliced. If this process is not highly regulated and accurate, it leads to mis-splicing events, which may result in proteins with altered function. A growing body of work has implicated mis-splicing events in a range of diseases, including cancer, neurodegenerative diseases, and muscular dystrophies. Understanding the mechanisms that cause aberrant splicing events and how this leads to disease is vital for designing effective therapeutic strategies. In this review, we focus on advances in therapies targeting splicing, and highlight the animal models developed to recapitulate disease phenotypes as a model for testing these therapies.
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Affiliation(s)
- Matías Montes
- Molecular, Cellular, and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA; Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Brianne L Sanford
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Daniel F Comiskey
- Molecular, Cellular, and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA; Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Dawn S Chandler
- Molecular, Cellular, and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA; Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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24
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Cutrupi AN, Brewer MH, Nicholson GA, Kennerson M. Structural variations causing inherited peripheral neuropathies: A paradigm for understanding genomic organization, chromatin interactions, and gene dysregulation. Mol Genet Genomic Med 2018; 6:422-433. [PMID: 29573232 PMCID: PMC6014456 DOI: 10.1002/mgg3.390] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/09/2018] [Accepted: 03/01/2018] [Indexed: 11/16/2022] Open
Abstract
Inherited peripheral neuropathies (IPNs) are a clinically and genetically heterogeneous group of diseases affecting the motor and sensory peripheral nerves. IPNs have benefited from gene discovery and genetic diagnosis using next-generation sequencing with over 80 causative genes available for testing. Despite this success, up to 50% of cases remain genetically unsolved. In the absence of protein coding mutations, noncoding DNA or structural variation (SV) mutations are a possible explanation. The most common IPN, Charcot-Marie-Tooth neuropathy type 1A (CMT1A), is caused by a 1.5 Mb duplication causing trisomy of the dosage sensitive gene PMP22. Using genome sequencing, we recently identified two large genomic rearrangements causing IPN subtypes X-linked CMT (CMTX3) and distal hereditary motor neuropathy (DHMN1), thereby expanding the spectrum of SV mutations causing IPN. Understanding how newly discovered SVs can cause IPN may serve as a useful paradigm to examine the role of topologically associated domains (TADs), chromatin interactions, and gene dysregulation in disease. This review will describe the growing role of SV in the pathogenesis of IPN and the importance of considering this type of mutation in Mendelian diseases where protein coding mutations cannot be identified.
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Affiliation(s)
- Anthony N. Cutrupi
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Megan H. Brewer
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Garth A. Nicholson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
| | - Marina L. Kennerson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
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25
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Kitada T, DiAndreth B, Teague B, Weiss R. Programming gene and engineered-cell therapies with synthetic biology. Science 2018; 359:359/6376/eaad1067. [PMID: 29439214 DOI: 10.1126/science.aad1067] [Citation(s) in RCA: 167] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gene and engineered-cell therapies promise to treat diseases by genetically modifying cells to carry out therapeutic tasks. Although the field has had some success in treating monogenic disorders and hematological malignancies, current approaches are limited to overexpression of one or a few transgenes, constraining the diseases that can be treated with this approach and leading to potential concerns over safety and efficacy. Synthetic gene networks can regulate the dosage, timing, and localization of gene expression and therapeutic activity in response to small molecules and disease biomarkers. Such "programmable" gene and engineered-cell therapies will provide new interventions for incurable or difficult-to-treat diseases.
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Affiliation(s)
- Tasuku Kitada
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Breanna DiAndreth
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Brian Teague
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ron Weiss
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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26
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Lin X, Li JJ, Qian WJ, Zhang QJ, Wang ZF, Lu YQ, Dong EL, He J, Wang N, Ma LX, Chen WJ. Modeling the differential phenotypes of spinal muscular atrophy with high-yield generation of motor neurons from human induced pluripotent stem cells. Oncotarget 2018; 8:42030-42042. [PMID: 28159932 PMCID: PMC5522047 DOI: 10.18632/oncotarget.14925] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 12/27/2016] [Indexed: 12/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating motor neuron disease caused by mutations of the survival motor neuron 1 (SMN1) gene. SMN2, a paralogous gene to SMN1, can partially compensate for the loss of SMN1. On the basis of age at onset, highest motor function and SMN2 copy numbers, childhood-onset SMA can be divided into three types (SMA I-III). An inverse correlation was observed between SMN2 copies and the differential phenotypes of SMA. Interestingly, this correlation is not always absolute. Using SMA induced pluripotent stem cells (iPSCs), we found that the SMN was significantly decreased in both SMA III and SMA I iPSCs derived postmitotic motor neurons (pMNs) and γ-aminobutyric acid (GABA) neurons. Moreover, the significant differences of SMN expression level between SMA III (3 copies of SMN2) and SMA I (2 copies of SMN2) were observed only in pMNs culture, but not in GABA neurons or iPSCs. From these findings, we further discovered that the neurite outgrowth was suppressed in both SMA III and SMA I derived MNs. Meanwhile, the significant difference of neurite outgrowth between SMA III and SMA I group was also found in long-term cultures. However, significant hyperexcitability was showed only in SMA I derived mature MNs, but not in SMA III group. Above all, we propose that SMN protein is a major factor of phenotypic modifier. Our data may provide a new insight into recognition for differential phenotypes of SMA disease.
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Affiliation(s)
- Xiang Lin
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Jin-Jing Li
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Wen-Jing Qian
- Institutes of Brain Science, Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Qi-Jie Zhang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Zhong-Feng Wang
- Institutes of Brain Science, Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Ying-Qian Lu
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - En-Lin Dong
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Jin He
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Li-Xiang Ma
- Department of Anatomy, Histology & Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
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27
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Investigation of New Morpholino Oligomers to Increase Survival Motor Neuron Protein Levels in Spinal Muscular Atrophy. Int J Mol Sci 2018; 19:ijms19010167. [PMID: 29316633 PMCID: PMC5796116 DOI: 10.3390/ijms19010167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/22/2017] [Accepted: 01/02/2018] [Indexed: 11/23/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal-recessive childhood motor neuron disease and the main genetic cause of infant mortality. SMA is caused by deletions or mutations in the survival motor neuron 1 (SMN1) gene, which results in SMN protein deficiency. Only one approved drug has recently become available and allows for the correction of aberrant splicing of the paralogous SMN2 gene by antisense oligonucleotides (ASOs), leading to production of full-length SMN protein. We have already demonstrated that a sequence of an ASO variant, Morpholino (MO), is particularly suitable because of its safety and efficacy profile and is both able to increase SMN levels and rescue the murine SMA phenotype. Here, we optimized this strategy by testing the efficacy of four new MO sequences targeting SMN2. Two out of the four new MO sequences showed better efficacy in terms of SMN protein production both in SMA induced pluripotent stem cells (iPSCs) and SMAΔ7 mice. Further, the effect was enhanced when different MO sequences were administered in combination. Our data provide an important insight for MO-based treatment for SMA. Optimization of the target sequence and validation of a treatment based on a combination of different MO sequences could support further pre-clinical studies and the progression toward future clinical trials.
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28
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Godfrey C, Desviat LR, Smedsrød B, Piétri-Rouxel F, Denti MA, Disterer P, Lorain S, Nogales-Gadea G, Sardone V, Anwar R, El Andaloussi S, Lehto T, Khoo B, Brolin C, van Roon-Mom WM, Goyenvalle A, Aartsma-Rus A, Arechavala-Gomeza V. Delivery is key: lessons learnt from developing splice-switching antisense therapies. EMBO Mol Med 2017; 9:545-557. [PMID: 28289078 PMCID: PMC5412803 DOI: 10.15252/emmm.201607199] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The use of splice‐switching antisense therapy is highly promising, with a wealth of pre‐clinical data and numerous clinical trials ongoing. Nevertheless, its potential to treat a variety of disorders has yet to be realized. The main obstacle impeding the clinical translation of this approach is the relatively poor delivery of antisense oligonucleotides to target tissues after systemic delivery. We are a group of researchers closely involved in the development of these therapies and would like to communicate our discussions concerning the validity of standard methodologies currently used in their pre‐clinical development, the gaps in current knowledge and the pertinent challenges facing the field. We therefore make recommendations in order to focus future research efforts and facilitate a wider application of therapeutic antisense oligonucleotides.
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Affiliation(s)
- Caroline Godfrey
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Lourdes R Desviat
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBERER, IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Bård Smedsrød
- Department of Medical Biology, University of Tromsø, Tromsø, Norway
| | | | - Michela A Denti
- Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Petra Disterer
- Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London, UK
| | - Stéphanie Lorain
- UPMC, INSERM, UMRS 974, CNRS FRE 3617, Institut de Myologie, Paris, France
| | - Gisela Nogales-Gadea
- Grup d'Investigació en Malalties Neuromusculars i Neuropediatriques, Institut d' Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona Barcelona, Spain
| | - Valentina Sardone
- Dubowitz Neuromuscular Centre and Developmental Neuroscience Programme, Institute of Child Health, University College London, London, UK
| | - Rayan Anwar
- Drug Discovery Informatics Lab, Qasemi-Research Center, Al-Qasemi Academic College, Baka El-Garbiah, Israel.,Drug Discovery and Development Laboratory, Institute of Applied Research, Galilee Society, Shefa-Amr, Israel
| | - Samir El Andaloussi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Taavi Lehto
- Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden.,Institute of Technology, University of Tartu, Tartu, Estonia
| | - Bernard Khoo
- Centre for Neuroendocrinology, Division of Medicine, University College London, London, UK
| | - Camilla Brolin
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Aurélie Goyenvalle
- INSERM U1179, UFR des sciences de la santé, Université Versailles Saint Quentin, Montigny-le-Bretonneux, France
| | - Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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29
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Magri F, Vanoli F, Corti S. miRNA in spinal muscular atrophy pathogenesis and therapy. J Cell Mol Med 2017; 22:755-767. [PMID: 29160009 PMCID: PMC5783860 DOI: 10.1111/jcmm.13450] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 10/03/2017] [Indexed: 02/06/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by the selective death of lower motor neurons in the brain stem and spinal cord. SMA is caused by mutations in the survival motor neuron 1 gene (SMN1), leading to the reduced expression of the full-length SMN protein. microRNAs (miRNAs) are small RNAs that regulate post-transcriptional gene expression. Recent findings have suggested an important role for miRNAs in the pathogenesis of motor neuron diseases, including SMA. Motor neuron-specific miRNA dysregulation in SMA might be implicated in their selective vulnerability. In this study, we discuss recent findings regarding the consequences of SMN defects on miRNAs and their target mRNAs in motor neurons. Taken together, these data suggest that cell-specific changes in miRNAs are not only involved in the SMA motor neuron phenotype but can also be used as biomarkers and therapeutic targets.
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Affiliation(s)
- Francesca Magri
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Fiammetta Vanoli
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy.,Department of Neurological Sciences, Mental Health and Sensory Organs (NESMOS), "Sapienza" University of Rome, Rome, Italy
| | - Stefania Corti
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
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30
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Genome-wide RNA-seq of iPSC-derived motor neurons indicates selective cytoskeletal perturbation in Brown-Vialetto disease that is partially rescued by riboflavin. Sci Rep 2017; 7:46271. [PMID: 28382968 PMCID: PMC5382781 DOI: 10.1038/srep46271] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/14/2017] [Indexed: 12/14/2022] Open
Abstract
Riboflavin is essential in numerous cellular oxidation/reduction reactions but is not synthesized by mammalian cells. Riboflavin absorption occurs through the human riboflavin transporters RFVT1 and RFVT3 in the intestine and RFVT2 in the brain. Mutations in these genes are causative for the Brown–Vialetto–Van Laere (BVVL), childhood-onset syndrome characterized by a variety of cranial nerve palsies as well as by spinal cord motor neuron (MN) degeneration. Why mutations in RFVTs result in a neural cell–selective disorder is unclear. As a novel tool to gain insights into the pathomechanisms underlying the disease, we generated MNs from induced pluripotent stem cells (iPSCs) derived from BVVL patients as an in vitro disease model. BVVL-MNs explained a reduction in axon elongation, partially improved by riboflavin supplementation. RNA sequencing profiles and protein studies of the cytoskeletal structures showed a perturbation in the neurofilament composition in BVVL-MNs. Furthermore, exploring the autophagy–lysosome pathway, we observed a reduced autophagic/mitophagic flux in patient MNs. These features represent emerging pathogenetic mechanisms in BVVL-associated neurodegeneration, partially rescued by riboflavin supplementation. Our data showed that this therapeutic strategy could have some limits in rescuing all of the disease features, suggesting the need to develop complementary novel therapeutic strategies.
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31
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Balestra D, Scalet D, Pagani F, Rogalska ME, Mari R, Bernardi F, Pinotti M. An Exon-Specific U1snRNA Induces a Robust Factor IX Activity in Mice Expressing Multiple Human FIX Splicing Mutants. MOLECULAR THERAPY-NUCLEIC ACIDS 2016; 5:e370. [PMID: 27701399 PMCID: PMC5095682 DOI: 10.1038/mtna.2016.77] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/21/2016] [Indexed: 12/30/2022]
Abstract
In cellular models we have demonstrated that a unique U1snRNA targeting an intronic region downstream of a defective exon (Exon-specific U1snRNA, ExSpeU1) can rescue multiple exon-skipping mutations, a relevant cause of genetic disease. Here, we explored in mice the ExSpeU1 U1fix9 toward two model Hemophilia B-causing mutations at the 5′ (c.519A > G) or 3′ (c.392-8T > G) splice sites of F9 exon 5. Hydrodynamic injection of wt-BALB/C mice with plasmids expressing the wt and mutant (hFIX-2G5′ss and hFIX-8G3′ss) splicing-competent human factor IX (hFIX) cassettes resulted in the expression of hFIX transcripts lacking exon 5 in liver, and in low plasma levels of inactive hFIX. Coinjection of U1fix9, but not of U1wt, restored exon inclusion of variants and in the intrinsically weak FIXwt context. This resulted in appreciable circulating hFIX levels (mean ± SD; hFIX-2G5′ss, 1.0 ± 0.5 µg/ml; hFIX-8G3′ss, 1.2 ± 0.3 µg/ml; and hFIXwt, 1.9 ± 0.6 µg/ml), leading to a striking shortening (from ~100 seconds of untreated mice to ~80 seconds) of FIX-dependent coagulation times, indicating a hFIX with normal specific activity. This is the first proof-of-concept in vivo that a unique ExSpeU1 can efficiently rescue gene expression impaired by distinct exon-skipping variants, which extends the applicability of ExSpeU1s to panels of mutations and thus cohort of patients.
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Affiliation(s)
- Dario Balestra
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Daniela Scalet
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Franco Pagani
- Internation Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Rosella Mari
- Haemostasis & Thrombosis Center, University of Ferrara, Ferrara, Italy
| | - Francesco Bernardi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.,LTTA Center, University of Ferrara, Ferrara, Italy
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.,LTTA Center, University of Ferrara, Ferrara, Italy
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32
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Barral S, Kurian MA. Utility of Induced Pluripotent Stem Cells for the Study and Treatment of Genetic Diseases: Focus on Childhood Neurological Disorders. Front Mol Neurosci 2016; 9:78. [PMID: 27656126 PMCID: PMC5012159 DOI: 10.3389/fnmol.2016.00078] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/15/2016] [Indexed: 12/15/2022] Open
Abstract
The study of neurological disorders often presents with significant challenges due to the inaccessibility of human neuronal cells for further investigation. Advances in cellular reprogramming techniques, have however provided a new source of human cells for laboratory-based research. Patient-derived induced pluripotent stem cells (iPSCs) can now be robustly differentiated into specific neural subtypes, including dopaminergic, inhibitory GABAergic, motorneurons and cortical neurons. These neurons can then be utilized for in vitro studies to elucidate molecular causes underpinning neurological disease. Although human iPSC-derived neuronal models are increasingly regarded as a useful tool in cell biology, there are a number of limitations, including the relatively early, fetal stage of differentiated cells and the mainly two dimensional, simple nature of the in vitro system. Furthermore, clonal variation is a well-described phenomenon in iPSC lines. In order to account for this, robust baseline data from multiple control lines is necessary to determine whether a particular gene defect leads to a specific cellular phenotype. Over the last few years patient-derived neural cells have proven very useful in addressing several mechanistic questions related to central nervous system diseases, including early-onset neurological disorders of childhood. Many studies report the clinical utility of human-derived neural cells for testing known drugs with repurposing potential, novel compounds and gene therapies, which then can be translated to clinical reality. iPSCs derived neural cells, therefore provide great promise and potential to gain insight into, and treat early-onset neurological disorders.
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Affiliation(s)
- Serena Barral
- Neurogenetics Group, Molecular Neurosciences, UCL Institute of Child Health,University College London London, UK
| | - Manju A Kurian
- Neurogenetics Group, Molecular Neurosciences, UCL Institute of Child Health,University College LondonLondon, UK; Department of Neurology, Great Ormond Street HospitalLondon, UK
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33
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Mis MSC, Brajkovic S, Tafuri F, Bresolin N, Comi GP, Corti S. Development of Therapeutics for C9ORF72 ALS/FTD-Related Disorders. Mol Neurobiol 2016; 54:4466-4476. [PMID: 27349438 DOI: 10.1007/s12035-016-9993-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/14/2016] [Indexed: 12/13/2022]
Abstract
The identification of the hexanucleotide repeat expansion (HRE) GGGGCC (G4C2) in the non-coding region of the C9ORF72 gene as the most frequent genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) has opened the path for advances in the knowledge and treatment of these disorders, which remain incurable. Recent evidence suggests that HRE RNA can cause gain-of-function neurotoxicity, but haploinsufficiency has also been hypothesized. In this review, we describe the recent developments in therapeutic targeting of the pathological expansion of C9ORF72 for ALS, FTD, and other neurodegenerative disorders. Three approaches are prominent: (1) an antisense oligonucleotides/RNA interference strategy; (2) using small compounds to counteract the toxic effects directly exerted by RNA derived from the repeat transcription (foci), by the translation of dipeptide repeat proteins (DPRs) from the repeated sequence, or by the sequestration of RNA-binding proteins from the C9ORF72 expansion; and (3) gene therapy, not only for silencing the toxic RNA/protein, but also for rescuing haploinsufficiency caused by the reduced transcription of the C9ORF72 coding sequence or by the diminished availability of RNA-binding proteins that are sequestered by RNA foci. Finally, with the perspective of clinical therapy, we discuss the most promising progress that has been achieved to date in the field.
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Affiliation(s)
- Maria Sara Cipolat Mis
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Simona Brajkovic
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Francesco Tafuri
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.
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Molecular Basis and Therapeutic Strategies to Rescue Factor IX Variants That Affect Splicing and Protein Function. PLoS Genet 2016; 12:e1006082. [PMID: 27227676 PMCID: PMC4882169 DOI: 10.1371/journal.pgen.1006082] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/04/2016] [Indexed: 12/24/2022] Open
Abstract
Mutations that result in amino acid changes can affect both pre-mRNA splicing and protein function. Understanding the combined effect is essential for correct diagnosis and for establishing the most appropriate therapeutic strategy at the molecular level. We have identified a series of disease-causing splicing mutations in coagulation factor IX (FIX) exon 5 that are completely recovered by a modified U1snRNP particle, through an SRSF2-dependent enhancement mechanism. We discovered that synonymous mutations and missense substitutions associated to a partial FIX secretion defect represent targets for this therapy as the resulting spliced-corrected proteins maintains normal FIX coagulant specific activity. Thus, splicing and protein alterations contribute to define at the molecular level the disease-causing effect of a number of exonic mutations in coagulation FIX exon 5. In addition, our results have a significant impact in the development of splicing-switching therapies in particular for mutations that affect both splicing and protein function where increasing the amount of a correctly spliced protein can circumvent the basic functional defects.
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Ahmad S, Bhatia K, Kannan A, Gangwani L. Molecular Mechanisms of Neurodegeneration in Spinal Muscular Atrophy. J Exp Neurosci 2016; 10:39-49. [PMID: 27042141 PMCID: PMC4807884 DOI: 10.4137/jen.s33122] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/22/2016] [Accepted: 02/25/2016] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease with a high incidence and is the most common genetic cause of infant mortality. SMA is primarily characterized by degeneration of the spinal motor neurons that leads to skeletal muscle atrophy followed by symmetric limb paralysis, respiratory failure, and death. In humans, mutation of the Survival Motor Neuron 1 (SMN1) gene shifts the load of expression of SMN protein to the SMN2 gene that produces low levels of full-length SMN protein because of alternative splicing, which are sufficient for embryonic development and survival but result in SMA. The molecular mechanisms of the (a) regulation of SMN gene expression and (b) degeneration of motor neurons caused by low levels of SMN are unclear. However, some progress has been made in recent years that have provided new insights into understanding of the cellular and molecular basis of SMA pathogenesis. In this review, we have briefly summarized recent advances toward understanding of the molecular mechanisms of regulation of SMN levels and signaling mechanisms that mediate neurodegeneration in SMA.
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Affiliation(s)
- Saif Ahmad
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
| | - Kanchan Bhatia
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
| | - Annapoorna Kannan
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
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Daguenet E, Dujardin G, Valcárcel J. The pathogenicity of splicing defects: mechanistic insights into pre-mRNA processing inform novel therapeutic approaches. EMBO Rep 2015; 16:1640-55. [PMID: 26566663 DOI: 10.15252/embr.201541116] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/12/2015] [Indexed: 12/22/2022] Open
Abstract
Removal of introns from pre-mRNA precursors (pre-mRNA splicing) is a necessary step for the expression of most genes in multicellular organisms, and alternative patterns of intron removal diversify and regulate the output of genomic information. Mutation or natural variation in pre-mRNA sequences, as well as in spliceosomal components and regulatory factors, has been implicated in the etiology and progression of numerous pathologies. These range from monogenic to multifactorial genetic diseases, including metabolic syndromes, muscular dystrophies, neurodegenerative and cardiovascular diseases, and cancer. Understanding the molecular mechanisms associated with splicing-related pathologies can provide key insights into the normal function and physiological context of the complex splicing machinery and establish sound basis for novel therapeutic approaches.
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Affiliation(s)
- Elisabeth Daguenet
- Centre de Regulació Genòmica (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain Universitat Pompeu-Fabra, Barcelona, Spain
| | - Gwendal Dujardin
- Centre de Regulació Genòmica (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain Universitat Pompeu-Fabra, Barcelona, Spain
| | - Juan Valcárcel
- Centre de Regulació Genòmica (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain Universitat Pompeu-Fabra, Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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