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Whalen M, Akula M, McNamee SM, DeAngelis MM, Haider NB. Seeing the Future: A Review of Ocular Therapy. Bioengineering (Basel) 2024; 11:179. [PMID: 38391665 PMCID: PMC10886198 DOI: 10.3390/bioengineering11020179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/03/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
Ocular diseases present a unique challenge and opportunity for therapeutic development. The eye has distinct advantages as a therapy target given its accessibility, compartmentalization, immune privilege, and size. Various methodologies for therapeutic delivery in ocular diseases are under investigation that impact long-term efficacy, toxicity, invasiveness, and delivery range. While gene, cell, and antibody therapy and nanoparticle delivery directly treat regions that have been damaged by disease, they can be limited in the duration of the therapeutic delivery and have a focal effect. In contrast, contact lenses and ocular implants can more effectively achieve sustained and widespread delivery of therapies; however, they can increase dilution of therapeutics, which may result in reduced effectiveness. Current therapies either offer a sustained release or a broad therapeutic effect, and future directions should aim toward achieving both. This review discusses current ocular therapy delivery systems and their applications, mechanisms for delivering therapeutic products to ocular tissues, advantages and challenges associated with each delivery system, current approved therapies, and clinical trials. Future directions for the improvement in existing ocular therapies include combination therapies, such as combined cell and gene therapies, as well as AI-driven devices, such as cortical implants that directly transmit visual information to the cortex.
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Affiliation(s)
- Maiya Whalen
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | | | | | - Margaret M DeAngelis
- Department of Ophthalmology, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Neena B Haider
- Shifa Precision, Boston, MA 02138, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02138, USA
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2
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Kerschensteiner D. Losing, preserving, and restoring vision from neurodegeneration in the eye. Curr Biol 2023; 33:R1019-R1036. [PMID: 37816323 PMCID: PMC10575673 DOI: 10.1016/j.cub.2023.08.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
The retina is a part of the brain that sits at the back of the eye, looking out onto the world. The first neurons of the retina are the rod and cone photoreceptors, which convert changes in photon flux into electrical signals that are the basis of vision. Rods and cones are frequent targets of heritable neurodegenerative diseases that cause visual impairment, including blindness, in millions of people worldwide. This review summarizes the diverse genetic causes of inherited retinal degenerations (IRDs) and their convergence onto common pathogenic mechanisms of vision loss. Currently, there are few effective treatments for IRDs, but recent advances in disparate areas of biology and technology (e.g., genome editing, viral engineering, 3D organoids, optogenetics, semiconductor arrays) discussed here enable promising efforts to preserve and restore vision in IRD patients with implications for neurodegeneration in less approachable brain areas.
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Affiliation(s)
- Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO 63110, USA.
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3
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Tawfik M, Chen F, Goldberg JL, Sabel BA. Nanomedicine and drug delivery to the retina: current status and implications for gene therapy. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2022; 395:1477-1507. [PMID: 36107200 PMCID: PMC9630211 DOI: 10.1007/s00210-022-02287-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/31/2022] [Indexed: 10/14/2022]
Abstract
Blindness affects more than 60 million people worldwide. Retinal disorders, including age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma, are the leading causes of blindness. Finding means to optimize local and sustained delivery of drugs or genes to the eye and retina is one goal to advance the development of new therapeutics. Despite the ease of accessibility of delivering drugs via the ocular surface, the delivery of drugs to the retina is still challenging due to anatomic and physiologic barriers. Designing a suitable delivery platform to overcome these barriers should enhance drug bioavailability and provide a safe, controlled, and sustained release. Current inventions for posterior segment treatments include intravitreal implants and subretinal viral gene delivery that satisfy these criteria. Several other novel drug delivery technologies, including nanoparticles, micelles, dendrimers, microneedles, liposomes, and nanowires, are now being widely studied for posterior segment drug delivery, and extensive research on gene delivery using siRNA, mRNA, or aptamers is also on the rise. This review discusses the current state of retinal drug/gene delivery and highlights future therapeutic opportunities.
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Affiliation(s)
- Mohamed Tawfik
- Institute of Medical Psychology, Medical Faculty, Otto-Von-Guericke University, Magdeburg, Germany
| | - Fang Chen
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-Von-Guericke University, Magdeburg, Germany.
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Leroy BP, Fischer MD, Flannery JG, MacLaren RE, Dalkara D, Scholl HPN, Chung DC, Spera C, Viriato D, Banhazi J. Gene Therapy for Inherited Retinal Disease: Long-Term Durability of Effect. Ophthalmic Res 2022; 66:179-196. [PMID: 36103843 DOI: 10.1159/000526317] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/27/2022] [Indexed: 12/23/2023]
Abstract
The recent approval of voretigene neparvovec (Luxturna®) for patients with biallelic RPE65 mutation-associated inherited retinal dystrophy with viable retinal cells represents an important step in the development of ocular gene therapies. Herein, we review studies investigating the episomal persistence of different recombinant adeno-associated virus (rAAV) vector genomes and the preclinical and clinical evidence of long-term effects of different RPE65 gene replacement therapies. A targeted review of articles published between 1974 and January 2021 in Medline®, Embase®, and other databases was conducted, followed by a descriptive longitudinal analysis of the clinical trial outcomes of voretigene neparvovec. Following an initial screening, 14 publications examining the episomal persistence of different rAAV genomes and 71 publications evaluating gene therapies in animal models were included. Viral genomes were found to persist for at least 22 months (longest study follow-up) as transcriptionally active episomes. Treatment effects lasting almost a decade were reported in canine disease models, with more pronounced effects the earlier the intervention. The clinical trial outcomes of voretigene neparvovec are consistent with preclinical findings and reveal sustained results for up to 7.5 years for the full-field light sensitivity threshold test and 5 years for the multi-luminance mobility test in the Phase I and Phase III trials, respectively. In conclusion, the therapeutic effect of voretigene neparvovec lasts for at least a decade in animal models and 7.5 years in human subjects. Since retinal cells can retain functionality over their lifetime after transduction, these effects may be expected to last even longer in patients with a sufficient number of outer retinal cells at the time of intervention.
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Affiliation(s)
- Bart P Leroy
- Department of Ophthalmology & Centre for Medical Genetics, Ghent University Hospital & Ghent University, Ghent, Belgium
- Division of Ophthalmology & Center for Cellular & Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - M Dominik Fischer
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
- Oxford Eye Hospital, University of Oxford NHS Foundation Trust and NIHR Oxford Biomedical Research Centre, Oxford, UK
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - John G Flannery
- School of Optometry and the Helen Wills Neuroscience Institute, University of California-Berkeley, Berkeley, California, USA
| | - Robert E MacLaren
- Oxford Eye Hospital, University of Oxford NHS Foundation Trust and NIHR Oxford Biomedical Research Centre, Oxford, UK
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, University of Basel, Basel, Switzerland
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Arsenijevic Y, Berger A, Udry F, Kostic C. Lentiviral Vectors for Ocular Gene Therapy. Pharmaceutics 2022; 14:pharmaceutics14081605. [PMID: 36015231 PMCID: PMC9414879 DOI: 10.3390/pharmaceutics14081605] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/14/2022] [Accepted: 07/22/2022] [Indexed: 12/10/2022] Open
Abstract
This review offers the basics of lentiviral vector technologies, their advantages and pitfalls, and an overview of their use in the field of ophthalmology. First, the description of the global challenges encountered to develop safe and efficient lentiviral recombinant vectors for clinical application is provided. The risks and the measures taken to minimize secondary effects as well as new strategies using these vectors are also discussed. This review then focuses on lentiviral vectors specifically designed for ocular therapy and goes over preclinical and clinical studies describing their safety and efficacy. A therapeutic approach using lentiviral vector-mediated gene therapy is currently being developed for many ocular diseases, e.g., aged-related macular degeneration, retinopathy of prematurity, inherited retinal dystrophies (Leber congenital amaurosis type 2, Stargardt disease, Usher syndrome), glaucoma, and corneal fibrosis or engraftment rejection. In summary, this review shows how lentiviral vectors offer an interesting alternative for gene therapy in all ocular compartments.
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Affiliation(s)
- Yvan Arsenijevic
- Unit Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland;
- Correspondence: (Y.A.); (C.K.)
| | - Adeline Berger
- Group Epigenetics of ocular diseases, Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland;
| | - Florian Udry
- Unit Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland;
| | - Corinne Kostic
- Group for Retinal Disorder Research, Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, 1004 Lausanne, Switzerland
- Correspondence: (Y.A.); (C.K.)
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In vivo base editing rescues cone photoreceptors in a mouse model of early-onset inherited retinal degeneration. Nat Commun 2022; 13:1830. [PMID: 35383196 PMCID: PMC8983734 DOI: 10.1038/s41467-022-29490-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 03/17/2022] [Indexed: 12/17/2022] Open
Abstract
Leber congenital amaurosis (LCA) is the most common cause of inherited retinal degeneration in children. LCA patients with RPE65 mutations show accelerated cone photoreceptor dysfunction and death, resulting in early visual impairment. It is therefore crucial to develop a robust therapy that not only compensates for lost RPE65 function but also protects photoreceptors from further degeneration. Here, we show that in vivo correction of an Rpe65 mutation by adenine base editor (ABE) prolongs the survival of cones in an LCA mouse model. In vitro screening of ABEs and sgRNAs enables the identification of a variant that enhances in vivo correction efficiency. Subretinal delivery of ABE and sgRNA corrects up to 40% of Rpe65 transcripts, restores cone-mediated visual function, and preserves cones in LCA mice. Single-cell RNA-seq reveals upregulation of genes associated with cone phototransduction and survival. Our findings demonstrate base editing as a potential gene therapy that confers long-lasting retinal protection. Leber congenital amaurosis is caused by mutations in RPE65 and leads to retinal degeneration in children. Here, the authors show that in vivo base editing can prolong the survival of cone photoreceptors and rescue their function in a mouse model of the disease.
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Stem cell transplantation as a progressing treatment for retinitis pigmentosa. Cell Tissue Res 2022; 387:177-205. [PMID: 35001210 DOI: 10.1007/s00441-021-03551-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/27/2021] [Indexed: 11/02/2022]
Abstract
Retinal degenerative diseases such as retinitis pigmentosa (RP) are of the major causes of vision loss in developed countries. Despite the unclear pathophysiology, treatment methods have been investigated vastly in the past decades. This review article mainly discusses the advances in application of stem cell and progenitor transplantation for retinitis pigmentosa. Stem cell sources such as mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, neural stem cells, retinal progenitor cells, and olfactory ensheathing cells are discussed separately in addition to a brief description of two approaches for treatment of early-stage RP, including gene therapy and nutritional therapy.
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Koster C, van den Hurk KT, Lewallen CF, Talib M, ten Brink JB, Boon CJF, Bergen AA. The Lrat -/- Rat: CRISPR/Cas9 Construction and Phenotyping of a New Animal Model for Retinitis Pigmentosa. Int J Mol Sci 2021; 22:ijms22137234. [PMID: 34281288 PMCID: PMC8267968 DOI: 10.3390/ijms22137234] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/27/2021] [Accepted: 06/29/2021] [Indexed: 11/16/2022] Open
Abstract
PURPOSE We developed and phenotyped a pigmented knockout rat model for lecithin retinol acyltransferase (LRAT) using CRISPR/Cas9. The introduced mutation (c.12delA) is based on a patient group harboring a homologous homozygous frameshift mutation in the LRAT gene (c.12delC), causing a dysfunctional visual (retinoid) cycle. METHODS The introduced mutation was confirmed by DNA and RNA sequencing. The expression of Lrat was determined on both the RNA and protein level in wildtype and knockout animals using RT-PCR and immunohistochemistry. The retinal structure and function, as well as the visual behavior of the Lrat-/- and control rats, were characterized using scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), electroretinography (ERG) and vision-based behavioral assays. RESULTS Wildtype animals had high Lrat mRNA expression in multiple tissues, including the eye and liver. In contrast, hardly any expression was detected in Lrat-/- animals. LRAT protein was abundantly present in wildtype animals and absent in Lrat-/- animals. Lrat-/- animals showed progressively reduced ERG potentials compared to wildtype controls from two weeks of age onwards. Vison-based behavioral assays confirmed reduced vision. Structural abnormalities, such as overall retinal thinning, were observed in Lrat-/- animals. The retinal thickness in knockout rats was decreased to roughly 80% by four months of age. No functional or structural differences were observed between wildtype and heterozygote animals. CONCLUSIONS Our Lrat-/- rat is a new animal model for retinal dystrophy, especially for the LRAT-subtype of early-onset retinal dystrophies. This model has advantages over the existing mouse models and the RCS rat strain and can be used for translational studies of retinal dystrophies.
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Affiliation(s)
- Céline Koster
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
| | - Koen T. van den Hurk
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
| | - Colby F. Lewallen
- Georgia Institute of Technology, G.W. Woodruff School of Mechanical Engineering, Atlanta, GA 30313, USA;
| | - Mays Talib
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands; (M.T.); (C.J.F.B.)
| | - Jacoline B. ten Brink
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
| | - Camiel J. F. Boon
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands; (M.T.); (C.J.F.B.)
- Department of Ophthalmology, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands
| | - Arthur A. Bergen
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
- Department of Ophthalmology, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands
- The Netherlands Institute for Neuroscience (NIN-KNAW), 1105 BA Amsterdam, The Netherlands
- Correspondence:
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9
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Yang U, Gentleman S, Gai X, Gorin MB, Borchert MS, Lee TC, Villanueva A, Koenekoop R, Maguire AM, Bennett J, Redmond TM, Nagiel A. Utility of In Vitro Mutagenesis of RPE65 Protein for Verification of Mutational Pathogenicity Before Gene Therapy. JAMA Ophthalmol 2021; 137:1381-1388. [PMID: 31580392 DOI: 10.1001/jamaophthalmol.2019.3914] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Importance Next-generation sequencing can detect variants of uncertain significance (VUSs), for some of which gene therapy would not be advantageous. Therefore, the pathogenicity of compound heterozygous or homozygous variants should be confirmed before bilateral vitrectomy and administration of voretigene neparvovec-rzyl. Objective To describe an in vitro mutagenesis assay for assessing the pathogenicity of variants in the RPE65 gene. Design, Setting, and Participants This case series was conducted at 2 tertiary referral centers. Clinical history, imaging, and electrophysiologic testing results were reviewed from September 5, 2008, to December 31, 2019. Participants were 4 pediatric patients with Leber congenital amaurosis who were evaluated for or met the inclusion criteria for phase 1 to 3 clinical trials or were referred for voretigene neparvovec-rzyl treatment. Main Outcomes and Measures A functional assay was used to confirm the pathogenicity of novel RPE65 VUSs in 4 patients with Leber congenital amaurosis. Results Four patients with Leber congenital amaurosis had VUSs in RPE65. Patients 1 and 2 were siblings with the homozygous VUS c.311G>T p.(G104V). Patient 3 was a compound heterozygote with 1 known pathogenic allele, c.1202_1203insCTGG p.(Glu404AlafsTer4), and 1 VUS, c.311G>T p.(G104V), which segregated to separate alleles. Patient 4 was also a compound heterozygote with 1 pathogenic variant, c.11 + 5G>A, and 1 variant in trans, c.1399C>T p.(P467S). In vitro mutagenesis revealed that the G104V and P467S RPE65 proteins were catalytically inactive (0% isomerase activity). Patients 1 and 2 were excluded from participation in a phase 1 trial owing to high Adeno-associated virus 2 capsid-neutralizing antibodies. Patients 3 (G104V) and 4 (P467S) underwent successful surgical gene therapy with voretigene neparvovec-rzyl, and their response to lower white light intensity and visual field increased in fewer than 30 days after gene therapy intervention. Conclusions and Relevance Findings from this study suggest that, in patients with missense mutations in RPE65, functional assays of protein function can be performed to assess the pathogenicity of variants in both compound heterozygous and homozygous cases. Given the potential risks of gene therapy operations, in vitro RPE65 activity testing should be considered to avoid the possibility of treating a false genotype.
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Affiliation(s)
- Unikora Yang
- Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, California
| | - Susan Gentleman
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, Bethesda, Maryland
| | - Xiaowu Gai
- Center for Personalized Medicine, Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, California
| | - Michael B Gorin
- Division of Retinal Disorders and Ophthalmic Genetics, Stein Eye Institute, David Geffen School of Medicine, UCLA (University of California, Los Angeles)
| | - Mark S Borchert
- The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California.,USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Thomas C Lee
- The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California.,USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Adda Villanueva
- Retina Department Genomics Institute, Mejora Vision MD/Virtual Eye Care MD, Mérida, Yucatán, México.,Laboratoire de Diagnostic Moleculaire, Hôpital Maisonneuve Rosemont, Montreal, Quebec, Canada
| | - Robert Koenekoop
- Department of Paediatric Surgery, Montreal Children's Hospital, McGill University and McGill University Health Centre Research Institute, Montreal, Quebec, Canada.,Department of Human Genetics and Ophthalmology, Montreal Children's Hospital, McGill University and McGill University Health Centre Research Institute, Montreal, Quebec, Canada
| | - Albert M Maguire
- Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia.,F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia.,F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, Bethesda, Maryland
| | - Aaron Nagiel
- The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California.,USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles
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Annear MJ, Mowat FM, Occelli LM, Smith AJ, Curran PG, Bainbridge JW, Ali RR, Petersen-Jones SM. A Comprehensive Study of the Retinal Phenotype of Rpe65-Deficient Dogs. Cells 2021; 10:cells10010115. [PMID: 33435495 PMCID: PMC7827248 DOI: 10.3390/cells10010115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 01/04/2021] [Accepted: 01/06/2021] [Indexed: 01/09/2023] Open
Abstract
The Rpe65-deficient dog has been important for development of translational therapies of Leber congenital amaurosis type 2 (LCA2). The purpose of this study was to provide a comprehensive report of the natural history of retinal changes in this dog model. Rpe65-deficient dogs from 2 months to 10 years of age were assessed by fundus imaging, electroretinography (ERG) and vision testing (VT). Changes in retinal layer thickness were assessed by optical coherence tomography and on plastic retinal sections. ERG showed marked loss of retinal sensitivity, with amplitudes declining with age. Retinal thinning initially developed in the area centralis, with a slower thinning of the outer retina in other areas starting with the inferior retina. VT showed that dogs of all ages performed well in bright light, while at lower light levels they were blind. Retinal pigment epithelial (RPE) inclusions developed and in younger dogs and increased in size with age. The loss of photoreceptors was mirrored by a decline in ERG amplitudes. The slow degeneration meant that sufficient photoreceptors, albeit very desensitized, remained to allow for residual bright light vision in older dogs. This study shows the natural history of the Rpe65-deficient dog model of LCA2.
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Affiliation(s)
- Matthew J Annear
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA; (M.J.A.); (F.M.M.); (L.M.O.)
| | - Freya M Mowat
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA; (M.J.A.); (F.M.M.); (L.M.O.)
| | - Laurence M Occelli
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA; (M.J.A.); (F.M.M.); (L.M.O.)
| | - Alexander J Smith
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (A.J.S.); (J.W.B.); (R.R.A.)
| | - Paul G Curran
- Center for Statistical Consulting, Michigan State University, East Lansing, MI 48824, USA;
| | - James W Bainbridge
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (A.J.S.); (J.W.B.); (R.R.A.)
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - Robin R Ali
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (A.J.S.); (J.W.B.); (R.R.A.)
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA; (M.J.A.); (F.M.M.); (L.M.O.)
- Correspondence:
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11
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Holmgaard AB, Askou AL, Jensen EG, Alsing S, Bak RO, Mikkelsen JG, Corydon TJ. Targeted Knockout of the Vegfa Gene in the Retina by Subretinal Injection of RNP Complexes Containing Cas9 Protein and Modified sgRNAs. Mol Ther 2021; 29:191-207. [PMID: 33022212 PMCID: PMC7791085 DOI: 10.1016/j.ymthe.2020.09.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/20/2020] [Accepted: 09/20/2020] [Indexed: 12/21/2022] Open
Abstract
The therapeutic effect of retinal gene therapy using CRISPR/Cas9-mediated genome editing and knockout applications is dependent on efficient and safe delivery of gene-modifying tool kits. Recently, transient administration of single guide RNAs (sgRNAs) and SpCas9 proteins delivered as ribonucleoproteins (RNPs) has provided potent gene knockout in vitro. To improve efficacy of CRISPR-based gene therapy, we delivered RNPs containing SpCas9 protein complexed to chemically modified sgRNAs (msgRNAs). In K562 cells, msgRNAs significantly increased the insertion/deletion (indel) frequency (25%) compared with unmodified counterparts leading to robust knockout of the VEGFA gene encoding vascular endothelial growth factor A (96% indels). Likewise, in HEK293 cells, lipoplexes containing varying amounts of RNP and EGFP mRNA showed efficient VEGFA knockout (43% indels) and strong EGFP expression, indicative of efficacious functional knockout using small amounts of RNP. In mice, subretinal injections of equivalent lipoplexes yielded 6% indels in Vegfa of isolated EGFP-positive RPE cells. However, signs of toxicity following delivery of lipoplexes containing high amounts of RNP were observed. Although the mechanism resulting in the varying efficacy remains to be elucidated, our data suggest that a single subretinal injection of RNPs carrying msgRNAs and SpCas9 induces targeted retinal indel formation, thus providing a clinically relevant strategy relying on nonviral delivery of short-lived nuclease activity.
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Affiliation(s)
| | - Anne Louise Askou
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Sidsel Alsing
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Rasmus O Bak
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark; Aarhus Institute of Advanced Studies (AIAS), Aarhus University, 8000 Aarhus C, Denmark
| | | | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, 8200 Aarhus N, Denmark.
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Wang X, Shan X, Gregory-Evans K, Gregory-Evans CY. RNA-based therapies in animal models of Leber congenital amaurosis causing blindness. PRECISION CLINICAL MEDICINE 2020; 3:113-126. [PMID: 35692607 PMCID: PMC8985810 DOI: 10.1093/pcmedi/pbaa009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 11/14/2022] Open
Abstract
Abstract
Leber congenital amaurosis (LCA) is a severe, genetically heterogeneous recessive eye disease in which ~ 35% of gene mutations are in-frame nonsense mutations coding for loss-of-function premature termination codons (PTCs) in mRNA. Nonsense suppression therapy allows read-through of PTCs leading to production of full-length protein. A limitation of nonsense suppression is that nonsense-mediated decay (NMD) degrades PTC-containing RNA transcripts. The purpose of this study was to determine whether inhibition of NMD could improve nonsense suppression efficacy in vivo. Using a high-throughput approach in the recessive cep290 zebrafish model of LCA (cep290;Q1223X), we first tested the NMD inhibitor Amlexanox in combination with the nonsense suppression drug Ataluren. We observed reduced retinal cell death and improved visual function. With these positive data, we next investigated whether this strategy was also applicable across species in two mammalian models: Rd12 (rpe65;R44X) and Rd3 (rd3;R107X) mouse models of LCA. In the Rd12 model, cell death was reduced, RPE65 protein was produced, and in vivo visual function testing was improved. We establish for the first time that the mechanism of action of Amlexanox in Rd12 retina was through reduced UPF1 phosphorylation. In the Rd3 model, however, no beneficial effect was observed with Ataluren alone or in combination with Amlexanox. This variation in response establishes that some forms of nonsense mutation LCA can be targeted by RNA therapies, but that this needs to be verified for each genotype. The implementation of precision medicine by identifying better responders to specific drugs is essential for development of validated retinal therapies.
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Affiliation(s)
- Xia Wang
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
| | - Xianghong Shan
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
| | - Kevin Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
| | - Cheryl Y Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
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13
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Udry F, Decembrini S, Gamm DM, Déglon N, Kostic C, Arsenijevic Y. Lentiviral mediated RPE65 gene transfer in healthy hiPSCs-derived retinal pigment epithelial cells markedly increased RPE65 mRNA, but modestly protein level. Sci Rep 2020; 10:8890. [PMID: 32483256 PMCID: PMC7264209 DOI: 10.1038/s41598-020-65657-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 05/08/2020] [Indexed: 12/15/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a monolayer of cobblestone-like epithelial cells that accomplishes critical functions for the retina. Several protocols have been published to differentiate pluripotent stem cells into RPE cells suitable for disease modelling and therapy development. In our study, the RPE identity of human induced pluripotent stem cell (hiPSC)-derived RPE (iRPE) was extensively characterized, and then used to test a lentiviral-mediated RPE65 gene augmentation therapy. A dose study of the lentiviral vector revealed a dose-dependent effect of the vector on RPE65 mRNA levels. A marked increase of the RPE65 mRNA was also observed in the iRPE (100-fold) as well as in an experimental set with RPE derived from another hiPSC source and from foetal human RPE. Although iRPE displayed features close to bona fide RPE, no or a modest increase of the RPE65 protein level was observed depending on the protein detection method. Similar results were observed with the two other cell lines. The mechanism of RPE65 protein regulation remains to be elucidated, but the current work suggests that high vector expression will not produce an excess of the normal RPE65 protein level.
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Affiliation(s)
- Florian Udry
- Department of ophthalmology, Unit of Retinal Degeneration and Regeneration, University of Lausanne, Hôpital ophtalmique Jules-Gonin, 1004, Lausanne, Switzerland
| | - Sarah Decembrini
- Department of ophthalmology, Unit of Retinal Degeneration and Regeneration, University of Lausanne, Hôpital ophtalmique Jules-Gonin, 1004, Lausanne, Switzerland
- Department of Biomedicine, University Hospital Basel & University Basel, Hebelstr. 20, 4031, Basel, Switzerland
| | - David M Gamm
- McPherson Eye Research Institute, Waisman Center and Department of Ophthalmology and Visual Sciences, and University of Wisconsin-Madison, Madison, USA
| | - Nicole Déglon
- Neuroscience Research Center, Laboratory of Neurotherapies and Neuromodulation, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Corinne Kostic
- Department of ophthalmology, Unit of Retinal Degeneration and Regeneration, University of Lausanne, Hôpital ophtalmique Jules-Gonin, 1004, Lausanne, Switzerland
| | - Yvan Arsenijevic
- Department of ophthalmology, Unit of Retinal Degeneration and Regeneration, University of Lausanne, Hôpital ophtalmique Jules-Gonin, 1004, Lausanne, Switzerland.
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14
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Fahim AT, Sullivan LS, Bowne SJ, Jones KD, Wheaton DKH, Khan NW, Heckenlively JR, Jayasundera KT, Branham KH, Andrews CA, Othman MI, Karoukis AJ, Birch DG, Daiger SP. X-Chromosome Inactivation Is a Biomarker of Clinical Severity in Female Carriers of RPGR-Associated X-Linked Retinitis Pigmentosa. Ophthalmol Retina 2019; 4:510-520. [PMID: 31953110 DOI: 10.1016/j.oret.2019.11.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 11/16/2022]
Abstract
PURPOSE X-linked retinitis pigmentosa can manifest in female carriers with widely variable severity, whereas others remain unaffected. The contribution of X-chromosome inactivation (XCI) to phenotypic variation has been postulated but not demonstrated. Furthermore, the impact of genotype and genetic modifiers has been demonstrated in affected males but has not been well established in female carriers. The purpose of this study was to describe the scope of clinical phenotype in female carriers with mutations in RPGR and quantify the contribution of genotype, genetic modifiers, and XCI to phenotypic severity. DESIGN Cohort study. PARTICIPANTS Seventy-seven female carriers with RPGR mutations from 41 pedigrees. METHODS Coding single nucleotide polymorphisms were sequenced in candidate genetic modifier genes encoding known RPGR-interacting proteins. X-chromosome inactivation ratios were determined in genomic DNA isolated from blood (n = 42) and saliva (n = 20) using methylation status of X-linked polymorphic repeats. These genetic data were compared with disease severity based on quantitative clinical parameters. MAIN OUTCOME MEASURES Visual acuity, Humphrey visual field (HVF) results, full-field electroretinography results, and dark adaptation. RESULTS Most individuals at all ages were mildly affected or unaffected, whereas those who progressed to moderate or severe vision loss were older than 30 years. RPGR genotype was not associated with clinical severity. The D1264N variant in RPGRIP1L was associated with more severe disease. Skewed XCI toward inactivation of the normal RPGR allele was associated with more severe disease. The XCI ratio in both blood and saliva was a predictor of visual function as measured by HVF diameter, rod amplitude, flicker amplitude, and flicker implicit time. For carriers with extreme XCI skewing of 80:20 or more, 57% were affected severely compared with 8% for those with XCI of less than 80:20 (P = 0.002). CONCLUSIONS Female carriers with mutations in RPGR demonstrate widely variable clinical severity. X-chromosome inactivation ratios correlate with clinical severity and may serve as a predictor of clinically significant disease. Because RPGR gene therapy trials are underway, a future imperative exists to determine which carriers require intervention and when to intervene. X-chromosome inactivation analysis may be useful for identifying candidates for early intervention.
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Affiliation(s)
- Abigail T Fahim
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan.
| | - Lori S Sullivan
- Department of Genetics, University of Texas Health Science Center, Houston, Texas
| | - Sara J Bowne
- Department of Genetics, University of Texas Health Science Center, Houston, Texas
| | | | | | - Naheed W Khan
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - John R Heckenlively
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - K Thiran Jayasundera
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Kari H Branham
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Chris A Andrews
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Mohammad I Othman
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Athanasios J Karoukis
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | | | - Stephen P Daiger
- Department of Genetics, University of Texas Health Science Center, Houston, Texas
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15
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Askou AL, Alsing S, Benckendorff JNE, Holmgaard A, Mikkelsen JG, Aagaard L, Bek T, Corydon TJ. Suppression of Choroidal Neovascularization by AAV-Based Dual-Acting Antiangiogenic Gene Therapy. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 16:38-50. [PMID: 30825671 PMCID: PMC6393707 DOI: 10.1016/j.omtn.2019.01.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/28/2019] [Accepted: 01/28/2019] [Indexed: 01/15/2023]
Abstract
Vascular endothelial growth factor A (VEGFA) is involved in the pathogenesis of vasoproliferative retinal diseases, such as exudative age-related macular degeneration (AMD). The objective of this study was to investigate whether dual-acting therapy based on the simultaneous expression of anti-VEGFA microRNAs (miRNAs) and the secreted, antiangiogenic protein pigment endothelial-derived factor (PEDF) delivered by adeno-associated virus (AAV) vectors provides improved protection against choroidal neovascularization (CNV). To investigate this, a multigenic AAV vector allowing retina pigment epithelium (RPE)-specific expression of anti-VEGFA miRNAs and PEDF was engineered. Robust expression of PEDF, driven by the RPE-specific vitelliform macular dystrophy 2 promoter, was observed in human cells and in mouse retina. A significant reduction in CNV was observed in a laser-induced CNV mouse model 57 days post-injection of the AAV5 particles conveying either anti-VEGFA miRNA and PEDF dual therapy or anti-VEGFA miRNA monotherapy. Overall, CNV reduction was most prominent in animals receiving dual-acting therapy. In both cases, the reduction in CNV was accompanied by a significant attenuation of VEGFA. In conclusion, the presented data reveal that gene therapy targeting VEGFA via multigenic AAV vectors displays combined efficacy, suggesting that dual-acting therapy is an important tool in future eye gene therapy for the treatment of neovascular ocular diseases, including AMD.
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Affiliation(s)
- Anne Louise Askou
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Sidsel Alsing
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Andreas Holmgaard
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Lars Aagaard
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark
| | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
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16
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Rajala RVS. Therapeutic Benefits from Nanoparticles: The Potential Significance of Nanoscience in Retinal Degenerative Diseases. JOURNAL OF MOLECULAR BIOLOGY & THERAPEUTICS 2019; 1:44-55. [PMID: 34528026 PMCID: PMC8439377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Several nanotechnology podiums have gained remarkable attention in the area of medical sciences, including diagnostics and treatment. In the past decade, engineered multifunctional nanoparticles have served as drug and gene carriers. The most important aspect of translating nanoparticles from the bench to bedside is safety. These nanoparticles should not elicit any immune response and should not be toxic to humans or the environment. Lipid-based nanoparticles have been shown to be the least toxic for in vivo applications, and significant progress has been made in gene and drug delivery employing lipid-based nanoassemblies. Several excellent reviews and reports discuss the general use and application of lipid-based nanoparticles; our review focuses on the application of lipid-based nanoparticles for the treatment of ocular diseases, and recent advances in and updates on their use.
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Affiliation(s)
- Raju V S Rajala
- Departments of Ophthalmology, Physiology and Cell Biology, University of Oklahoma Health Sciences Center, Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
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17
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Mitsios A, Dubis AM, Moosajee M. Choroideremia: from genetic and clinical phenotyping to gene therapy and future treatments. Ther Adv Ophthalmol 2018; 10:2515841418817490. [PMID: 30627697 PMCID: PMC6311551 DOI: 10.1177/2515841418817490] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/05/2018] [Indexed: 11/15/2022] Open
Abstract
Choroideremia is an X-linked inherited chorioretinal dystrophy leading to blindness by late adulthood. Choroideremia is caused by mutations in the CHM gene which encodes Rab escort protein 1 (REP1), an ubiquitously expressed protein involved in intracellular trafficking and prenylation activity. The exact site of pathogenesis remains unclear but results in degeneration of the photoreceptors, retinal pigment epithelium and choroid. Animal and stem cell models have been used to study the molecular defects in choroideremia and test effectiveness of treatment interventions. Natural history studies of choroideremia have provided additional insight into the clinical phenotype of the condition and prepared the way for clinical trials aiming to investigate the safety and efficacy of suitable therapies. In this review, we provide a summary of the current knowledge on the genetics, pathophysiology, clinical features and therapeutic strategies that might become available for choroideremia in the future, including gene therapy, stem cell treatment and small-molecule drugs with nonsense suppression action.
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Affiliation(s)
- Andreas Mitsios
- Institute of Ophthalmology, University College London, London, UK
| | - Adam M Dubis
- Institute of Ophthalmology, University College London, London, UK
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, London, UK
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18
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Fu X, Huu VAN, Duan Y, Kermany DS, Valentim CCS, Zhang R, Zhu J, Zhang CL, Sun X, Zhang K. Clinical applications of retinal gene therapies. PRECISION CLINICAL MEDICINE 2018; 1:5-20. [PMID: 35694125 PMCID: PMC8982485 DOI: 10.1093/pcmedi/pby004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 02/05/2023] Open
Abstract
Retinal degenerative diseases are a major cause of blindness. Retinal gene therapy is a
trail-blazer in the human gene therapy field, leading to the first FDA approved gene
therapy product for a human genetic disease. The application of Clustered Regularly
Interspaced Short Palindromic Repeat/Cas9 (CRISPR/Cas9)-mediated gene editing technology
is transforming the delivery of gene therapy. We review the history, present, and future
prospects of retinal gene therapy.
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Affiliation(s)
- Xin Fu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Viet Anh Nguyen Huu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Yaou Duan
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Daniel S Kermany
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Carolina C S Valentim
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Runze Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jie Zhu
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Charlotte L Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Xiaodong Sun
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Jiaodong University, Shanghai, China
| | - Kang Zhang
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
- Molecular Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
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19
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Kumaran N, Smith AJ, Michaelides M, Ali R, Bainbridge J. Gene therapy for Leber congenital amaurosis. EXPERT REVIEW OF OPHTHALMOLOGY 2018. [DOI: 10.1080/17469899.2018.1429916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Neruban Kumaran
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Alexander J. Smith
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Robin Ali
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - James Bainbridge
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
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20
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Askou AL, Benckendorff JNE, Holmgaard A, Storm T, Aagaard L, Bek T, Mikkelsen JG, Corydon TJ. Suppression of Choroidal Neovascularization in Mice by Subretinal Delivery of Multigenic Lentiviral Vectors Encoding Anti-Angiogenic MicroRNAs. Hum Gene Ther Methods 2018; 28:222-233. [PMID: 28817343 DOI: 10.1089/hgtb.2017.079] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Lentivirus-based vectors have been used for the development of potent gene therapies. Here, application of a multigenic lentiviral vector (LV) producing multiple anti-angiogenic microRNAs following subretinal delivery in a laser-induced choroidal neovascularization (CNV) mouse model is presented. This versatile LV, carrying back-to-back RNApolII-driven expression cassettes, enables combined expression of microRNAs targeting vascular endothelial growth factor A (Vegfa) mRNA and fluorescent reporters. In addition, by including a vitelliform macular dystrophy 2 (VMD2) promoter, expression of microRNAs is restricted to the retinal pigment epithelial (RPE) cells. Six days post injection (PI), robust and widespread fluorescent signals of eGFP are already observed in the retina by funduscopy. The eGFP expression peaks at day 21 PI and persists with stable expression for at least 9 months. In parallel, prominent AsRED co-expression, encoded from the VMD2-driven microRNA expression cassette, is evident in retinal sections and flat-mounts, revealing RPE-specific expression of microRNAs. Furthermore, LV-delivered microRNAs targeting the Vegfa gene in RPE cells reduced the size of laser-induced CNV in mice 28 days PI, as a consequence of diminished VEGF levels, suggesting that LVs delivered locally are powerful tools in the development of gene therapy-based strategies for treatment of age-related macular degeneration.
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Affiliation(s)
| | | | | | - Tina Storm
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Lars Aagaard
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Toke Bek
- 2 Department of Ophthalmology, Aarhus University Hospital , Aarhus, Denmark
| | | | - Thomas Juhl Corydon
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark .,2 Department of Ophthalmology, Aarhus University Hospital , Aarhus, Denmark
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21
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Lalit PS, Thangal Y, Fayi Y, Takhellambam SD. Potentials of Gene Therapy for Diabetic Retinopathy: The Use of Nucleic Acid Constructs Containing a TXNIP Promoter. OPEN ACCESS JOURNAL OF OPHTHALMOLOGY 2018; 3. [PMID: 31106306 DOI: 10.23880/oajo-16000147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diabetic retinopathy (DR) is considered as a chronic eye disease leading to blindness. DR is associated with hyperglycemia-induced oxidative stress, chronic low-grade inflammation and premature cell death. DR affects retinal capillaries, neuroretina and the retinal pigment epithelium. Recently, the thioredoxin-interacting protein TXNIP has been shown as a pro-oxidative stress, pro-inflammatory and pro-apoptotic protein, highly induced by diabetes and high glucose in all cells examined including the retina. TXNIP's actions involve binding to and inhibition of anti-oxidant and thiol-reducing capacities of thioredoxins (Trx) causing cellular oxidative stress and apoptosis. Trx1 is found in the cytosol and nucleus while Trx2 is the mitochondrial isoform. Several studies provided evidence that knockdown of TXNIP by siRNA or chemical blockade ameliorates early abnormalities of DR including endothelial dysfunction, pericyte apoptosis, Müller cell gliosis and neurodegeneration. Therefore, TXNIP is considered a potential target for preventing or slowing down the progression of DR. We recently proposed that nucleic acid constructs containing a proximal TXNIP promoter linked to a redox gene or shRNA that reduces oxidative stress and inflammation may be used to treat DR. The TXNIP promoter is sensitive to hyperglycemia therefore can drive expression of the linked gene or shRNA under high glucose environment such as seen in diabetes while remaining unresponsive at physiological glucose levels. Such a TXNIP-promoter linked gene or shRNA construct can be delivered to the retina by using adeno-associated viral vectors including AAV2 and AAV2/8 or an appropriate carrier via the intravitreal or sub retinal delivery for long-term gene therapies in DR.
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Affiliation(s)
- P S Lalit
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, USA.,Department of Ophthalmology, Wayne State University School of Medicine, USA
| | - Y Thangal
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, USA
| | - Y Fayi
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, USA
| | - S D Takhellambam
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, USA
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22
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Evaluation of tolerance to lentiviral LV-RPE65 gene therapy vector after subretinal delivery in non-human primates. Transl Res 2017; 188:40-57.e4. [PMID: 28754419 DOI: 10.1016/j.trsl.2017.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 04/30/2017] [Accepted: 06/30/2017] [Indexed: 12/17/2022]
Abstract
Several approaches have been developed for gene therapy in RPE65-related Leber congenital amaurosis. To date, strategies that have reached the clinical stages rely on adeno-associated viral vectors and two of them documented limited long-term effect. We have developed a lentiviral-based strategy of RPE65 gene transfer that efficiently restored protein expression and cone function in RPE65-deficient mice. In this study, we evaluated the ocular and systemic tolerances of this lentiviral-based therapy (LV-RPE65) on healthy nonhuman primates (NHPs), without adjuvant systemic anti-inflammatory prophylaxis. For the first time, we describe the early kinetics of retinal detachment at 2, 4, and 7 days after subretinal injection using multimodal imaging in 5 NHPs. We revealed prolonged reattachment times in LV-RPE65-injected eyes compared to vehicle-injected eyes. Low- (n = 2) and high-dose (n = 2) LV-RPE65-injected eyes presented a reduction of the outer nuclear and photoreceptor outer segment layer thickness in the macula, that was more pronounced than in vehicle-injected eyes (n = 4). All LV-RPE65-injected eyes showed an initial perivascular reaction that resolved spontaneously within 14 days. Despite foveal structural changes, full-field electroretinography indicated that the overall retinal function was preserved over time and immunohistochemistry identified no difference in glial, microglial, or leucocyte ocular activation between low-dose, high-dose, and vehicle-injected eyes. Moreover, LV-RPE65-injected animals did not show signs of vector shedding or extraocular targeting, confirming the safe ocular restriction of the vector. Our results evidence a limited ocular tolerance to LV-RPE65 after subretinal injection without adjuvant anti-inflammatory prophylaxis, with complications linked to this route of administration necessitating to block this transient inflammatory event.
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23
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Holmgaard A, Askou AL, Benckendorff JNE, Thomsen EA, Cai Y, Bek T, Mikkelsen JG, Corydon TJ. In Vivo Knockout of the Vegfa Gene by Lentiviral Delivery of CRISPR/Cas9 in Mouse Retinal Pigment Epithelium Cells. MOLECULAR THERAPY-NUCLEIC ACIDS 2017; 9:89-99. [PMID: 29246327 PMCID: PMC5626917 DOI: 10.1016/j.omtn.2017.08.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/29/2017] [Accepted: 08/29/2017] [Indexed: 12/26/2022]
Abstract
Virus-based gene therapy by CRISPR/Cas9-mediated genome editing and knockout may provide a new option for treatment of inherited and acquired ocular diseases of the retina. In support of this notion, we show that Streptococcus pyogenes (Sp) Cas9, delivered by lentiviral vectors (LVs), can be used in vivo to selectively ablate the vascular endothelial growth factor A (Vegfa) gene in mice. By generating LVs encoding SpCas9 targeted to Vegfa, and in parallel the fluorescent eGFP marker protein, we demonstrate robust knockout of Vegfa that leads to a significant reduction of VEGFA protein in transduced cells. Three of the designed single-guide RNAs (sgRNAs) induce in vitro indel formation at high frequencies (44%-93%). A single unilateral subretinal injection facilitates RPE-specific localization of the vector and disruption of Vegfa in isolated eGFP+ RPE cells obtained from mice five weeks after LV administration. Notably, sgRNA delivery results in the disruption of Vegfa with an in vivo indel formation efficacy of up to 84%. Sequencing of Vegfa-specific amplicons reveals formation of indels, including 4-bp deletions and 2-bp insertions. Taken together, our data demonstrate the capacity of lentivirus-delivered SpCas9 and sgRNAs as a developing therapeutic path in the treatment of ocular diseases, including age-related macular degeneration.
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Affiliation(s)
- Andreas Holmgaard
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Anne Louise Askou
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | | | - Yujia Cai
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark
| | | | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
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24
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Singh LP, Devi TS, Yumnamcha T. The Role of Txnip in Mitophagy Dysregulation and Inflammasome Activation in Diabetic Retinopathy: A New Perspective. ACTA ACUST UNITED AC 2017; 4. [PMID: 29376145 PMCID: PMC5786434 DOI: 10.19080/jojo.2017.04.555643] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondria are responsible for bioenergetics, metabolism and apoptosis signals in health and disease. The retina being a part of the central nervous system consumes large amounts of glucose and oxygen to generate ATP via the mitochondrial oxidative phosphorylation for its phototransduction and visual function. During ATP generation, electrons leak from the mitochondrial electron transport chain, which is captured by molecular oxygen to produce reactive oxygen species (ROS). These mtROS damage mitochondrial proteins, mtDNA, and membrane lipids and release them in the cytosol. Mitochondrial components are recognized as danger-associated molecular patterns (DAMPS) by cytosolic pattern recognition receptors such as NOD-like receptors, NLRP3 inflammasomes. They process pro-caspase-1 to active caspase-1, which cleaves pro-inflammatory IL-1β o mature IL-1β causing inflammation and cell death by pyroptosis. To counter the damaging action of mtROS and inflammasomes in fully differentiated cells in the retina, the removal of the damaged and dysfunctional mitochondria by a double-membrane autophagic process via lysosomal degradation called mitophagy is critical for mitochondrial homeostasis and cell survival. Nonetheless, under chronic diseases including diabetic retinopathy (DR), mitophagy dysregulation and NLRP3 inflammasome activation exist, which cause premature cell death and disease progression. Recently, the thioredoxin-interacting protein TXNIP, which is strongly induced by diabetes and inhibits anti-oxidant function of thioredoxin, has been implicated in mitochondrial dysfunction, mitophagic dysregulation and NLRP3 inflammasome activation in DR. Therefore, TXNIP silencing or pharmacological inhibition may normalize mitophagic flux and NLRP3 inflammasome activation, which will prevent or slow down the progression of DR.
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Affiliation(s)
- Lalit P Singh
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, USA.,Department of Ophthalmology, Wayne State University School of Medicine, USA
| | - Takhellambam S Devi
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, USA
| | - Thangal Yumnamcha
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, USA
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25
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Kumaran N, Moore AT, Weleber RG, Michaelides M. Leber congenital amaurosis/early-onset severe retinal dystrophy: clinical features, molecular genetics and therapeutic interventions. Br J Ophthalmol 2017; 101:1147-1154. [PMID: 28689169 PMCID: PMC5574398 DOI: 10.1136/bjophthalmol-2016-309975] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/26/2017] [Accepted: 04/30/2017] [Indexed: 12/29/2022]
Abstract
Leber congenital amaurosis (LCA) and early-onset severe retinal dystrophy (EOSRD) are both genetically and phenotypically heterogeneous, and characterised clinically by severe congenital/early infancy visual loss, nystagmus, amaurotic pupils and markedly reduced/absent full-field electroretinograms. The vast genetic heterogeneity of inherited retinal disease has been established over the last 10 - 20 years, with disease-causing variants identified in 25 genes to date associated with LCA/EOSRD, accounting for 70–80% of cases, with thereby more genes yet to be identified. There is now far greater understanding of the structural and functional associations seen in the various LCA/EOSRD genotypes. Subsequent development/characterisation of LCA/EOSRD animal models has shed light on the underlying pathogenesis and allowed the demonstration of successful rescue with gene replacement therapy and pharmacological intervention in multiple models. These advancements have culminated in more than 12 completed, ongoing and anticipated phase I/II and phase III gene therapy and pharmacological human clinical trials. This review describes the clinical and genetic characteristics of LCA/EOSRD and the differential diagnoses to be considered. We discuss in further detail the diagnostic clinical features, pathophysiology, animal models and human treatment studies and trials, in the more common genetic subtypes and/or those closest to intervention.
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Affiliation(s)
- Neruban Kumaran
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,University of California San Francisco, San Francisco CA, California, USA
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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26
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Diessler S, Kostic C, Arsenijevic Y, Kawasaki A, Franken P. Rai1 frees mice from the repression of active wake behaviors by light. eLife 2017; 6. [PMID: 28548639 PMCID: PMC5464769 DOI: 10.7554/elife.23292] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 05/24/2017] [Indexed: 12/23/2022] Open
Abstract
Besides its role in vision, light impacts physiology and behavior through circadian and direct (aka ‘masking’) mechanisms. In Smith-Magenis syndrome (SMS), the dysregulation of both sleep-wake behavior and melatonin production strongly suggests impaired non-visual light perception. We discovered that mice haploinsufficient for the SMS causal gene, Retinoic acid induced-1 (Rai1), were hypersensitive to light such that light eliminated alert and active-wake behaviors, while leaving time-spent-awake unaffected. Moreover, variables pertaining to circadian rhythm entrainment were activated more strongly by light. At the input level, the activation of rod/cone and suprachiasmatic nuclei (SCN) by light was paradoxically greatly reduced, while the downstream activation of the ventral-subparaventricular zone (vSPVZ) was increased. The vSPVZ integrates retinal and SCN input and, when activated, suppresses locomotor activity, consistent with the behavioral hypersensitivity to light we observed. Our results implicate Rai1 as a novel and central player in processing non-visual light information, from input to behavioral output. DOI:http://dx.doi.org/10.7554/eLife.23292.001
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Affiliation(s)
- Shanaz Diessler
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Corinne Kostic
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Yvan Arsenijevic
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Aki Kawasaki
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.,Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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27
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Sun D, Sahu B, Gao S, Schur RM, Vaidya AM, Maeda A, Palczewski K, Lu ZR. Targeted Multifunctional Lipid ECO Plasmid DNA Nanoparticles as Efficient Non-viral Gene Therapy for Leber's Congenital Amaurosis. MOLECULAR THERAPY. NUCLEIC ACIDS 2017. [PMID: 28624218 PMCID: PMC5363681 DOI: 10.1016/j.omtn.2017.02.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Development of a gene delivery system with high efficiency and a good safety profile is essential for successful gene therapy. Here we developed a targeted non-viral delivery system using a multifunctional lipid ECO for treating Leber’s congenital amaurosis type 2 (LCA2) and tested this in a mouse model. ECO formed stable nanoparticles with plasmid DNA (pDNA) at a low amine to phosphate (N/P) ratio and mediated high gene transfection efficiency in ARPE-19 cells because of their intrinsic properties of pH-sensitive amphiphilic endosomal escape and reductive cytosolic release (PERC). All-trans-retinylamine, which binds to interphotoreceptor retinoid-binding protein (IRBP), was incorporated into the nanoparticles via a polyethylene glycol (PEG) spacer for targeted delivery of pDNA into the retinal pigmented epithelium. The targeted ECO/pDNA nanoparticles provided high GFP expression in the RPE of 1-month-old Rpe65−/− mice after subretinal injection. Such mice also exhibited a significant increase in electroretinographic activity, and this therapeutic effect continued for at least 120 days. A safety study in wild-type BALB/c mice indicated no irreversible retinal damage following subretinal injection of these targeted nanoparticles. All-trans-retinylamine-modified ECO/pDNA nanoparticles provide a promising non-viral platform for safe and effective treatment of RPE-specific monogenic eye diseases such as LCA2.
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Affiliation(s)
- Da Sun
- Case Center for Biomolecular Engineering and Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Bhubanananda Sahu
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Songqi Gao
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44140, USA
| | - Rebecca M Schur
- Case Center for Biomolecular Engineering and Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Amita M Vaidya
- Case Center for Biomolecular Engineering and Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Akiko Maeda
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Krzysztof Palczewski
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44140, USA
| | - Zheng-Rong Lu
- Case Center for Biomolecular Engineering and Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
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28
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Wang Y, Rajala A, Cao B, Ranjo-Bishop M, Agbaga MP, Mao C, Rajala RV. Cell-Specific Promoters Enable Lipid-Based Nanoparticles to Deliver Genes to Specific Cells of the Retina In Vivo. Theranostics 2016; 6:1514-27. [PMID: 27446487 PMCID: PMC4955052 DOI: 10.7150/thno.15230] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/08/2016] [Indexed: 12/03/2022] Open
Abstract
Non-viral vectors, such as lipid-based nanoparticles (liposome-protamine-DNA complex [LPD]), could be used to deliver a functional gene to the retina to correct visual function and treat blindness. However, one of the limitations of LPD is the lack of cell specificity, as the retina is composed of seven types of cells. If the same gene is expressed in multiple cell types or is absent from one desired cell type, LPD-mediated gene delivery to every cell may have off-target effects. To circumvent this problem, we have tested LPD-mediated gene delivery using various generalized, modified, and retinal cell-specific promoters. We achieved retinal pigment epithelium cell specificity with vitelliform macular dystrophy (VMD2), rod cell specificity with mouse rhodopsin, cone cell specificity with red/green opsin, and ganglion cell specificity with thymocyte antigen promoters. Here we show for the first time that cell-specific promoters enable lipid-based nanoparticles to deliver genes to specific cells of the retina in vivo. This work will inspire investigators in the field of lipid nanotechnology to couple cell-specific promoters to drive expression in a cell- and tissue-specific manner.
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29
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Update on ocular gene therapy and advances in treatment of inherited retinal diseases and exudative macular degeneration. Curr Opin Ophthalmol 2016; 27:268-73. [DOI: 10.1097/icu.0000000000000256] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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30
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Khabou H, Dalkara D. [Developments in gene delivery vectors for ocular gene therapy]. Med Sci (Paris) 2015; 31:529-37. [PMID: 26059304 DOI: 10.1051/medsci/20153105015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gene therapy is quickly becoming a reality applicable in the clinic for inherited retinal diseases. Its remarkable success in safety and efficacy, in clinical trials for Leber's congenital amaurosis (LCA) type II generated significant interest and opened up possibilities for a new era of retinal gene therapies. Success in these clinical trials was mainly due to the favorable characteristics of the retina as a target organ. The eye offers several advantages as it is readily accessible and has some degree of immune privilege making it suitable for application of viral vectors. The viral vectors most frequently used for retinal gene delivery are lentivirus, adenovirus and adeno-associated virus (AAV). Here we will discuss the use of these viral vectors in retinal gene delivery with a strong focus on favorable properties of AAV. Thanks to its small size, AAV diffuses well in the inter-neural matrix making it suitable for applications in neural retina. Building on this initial clinical success with LCA II, we have now many opportunities to extend this proof-of-concept to other retinal diseases using AAV as a vector. This article will discuss what are some of the most imminent cellular targets for such therapies and the AAV toolkit that has been built to target these cells successfully. We will also discuss some of the challenges that we face in translating AAV-based gene therapies to the clinic.
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Affiliation(s)
- Hanen Khabou
- Inserm UMR S968, Institut de la vision, 17, rue Moreau, 75012 Paris, France - Sorbonne universités, UPMC université Paris 6, UMR S968, 75012 Paris, France - CNRS, UMR 7210, 75012 Paris, France
| | - Deniz Dalkara
- Inserm UMR S968, Institut de la vision, 17, rue Moreau, 75012 Paris, France - Sorbonne universités, UPMC université Paris 6, UMR S968, 75012 Paris, France - CNRS, UMR 7210, 75012 Paris, France
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31
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Wang Y, Rajala A, Rajala RVS. Lipid Nanoparticles for Ocular Gene Delivery. J Funct Biomater 2015; 6:379-94. [PMID: 26062170 PMCID: PMC4493518 DOI: 10.3390/jfb6020379] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 06/01/2015] [Accepted: 06/02/2015] [Indexed: 02/07/2023] Open
Abstract
Lipids contain hydrocarbons and are the building blocks of cells. Lipids can naturally form themselves into nano-films and nano-structures, micelles, reverse micelles, and liposomes. Micelles or reverse micelles are monolayer structures, whereas liposomes are bilayer structures. Liposomes have been recognized as carriers for drug delivery. Solid lipid nanoparticles and lipoplex (liposome-polycation-DNA complex), also called lipid nanoparticles, are currently used to deliver drugs and genes to ocular tissues. A solid lipid nanoparticle (SLN) is typically spherical, and possesses a solid lipid core matrix that can solubilize lipophilic molecules. The lipid nanoparticle, called the liposome protamine/DNA lipoplex (LPD), is electrostatically assembled from cationic liposomes and an anionic protamine-DNA complex. The LPD nanoparticles contain a highly condensed DNA core surrounded by lipid bilayers. SLNs are extensively used to deliver drugs to the cornea. LPD nanoparticles are used to target the retina. Age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy are the most common retinal diseases in humans. There have also been promising results achieved recently with LPD nanoparticles to deliver functional genes and micro RNA to treat retinal diseases. Here, we review recent advances in ocular drug and gene delivery employing lipid nanoparticles.
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Affiliation(s)
- Yuhong Wang
- Dean A. McGee Eye Institute, Oklahoma City, OK 73104, USA.
- Department of Ophthalmology, College of Medicine, University of Oklahoma, Oklahoma City, OK 73014, USA.
| | - Ammaji Rajala
- Dean A. McGee Eye Institute, Oklahoma City, OK 73104, USA.
- Department of Ophthalmology, College of Medicine, University of Oklahoma, Oklahoma City, OK 73014, USA.
| | - Raju V S Rajala
- Dean A. McGee Eye Institute, Oklahoma City, OK 73104, USA.
- Department of Ophthalmology, College of Medicine, University of Oklahoma, Oklahoma City, OK 73014, USA.
- Department of Physiology and Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73014, USA.
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32
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Bainbridge JWB, Mehat MS, Sundaram V, Robbie SJ, Barker SE, Ripamonti C, Georgiadis A, Mowat FM, Beattie SG, Gardner PJ, Feathers KL, Luong VA, Yzer S, Balaggan K, Viswanathan A, de Ravel TJL, Casteels I, Holder GE, Tyler N, Fitzke FW, Weleber RG, Nardini M, Moore AT, Thompson DA, Petersen-Jones SM, Michaelides M, van den Born LI, Stockman A, Smith AJ, Rubin G, Ali RR. Long-term effect of gene therapy on Leber's congenital amaurosis. N Engl J Med 2015; 372:1887-97. [PMID: 25938638 PMCID: PMC4497809 DOI: 10.1056/nejmoa1414221] [Citation(s) in RCA: 528] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Mutations in RPE65 cause Leber's congenital amaurosis, a progressive retinal degenerative disease that severely impairs sight in children. Gene therapy can result in modest improvements in night vision, but knowledge of its efficacy in humans is limited. METHODS We performed a phase 1-2 open-label trial involving 12 participants to evaluate the safety and efficacy of gene therapy with a recombinant adeno-associated virus 2/2 (rAAV2/2) vector carrying the RPE65 complementary DNA, and measured visual function over the course of 3 years. Four participants were administered a lower dose of the vector, and 8 were administered a higher dose. In a parallel study in dogs, we investigated the relationship among vector dose, visual function, and electroretinography (ERG) findings. RESULTS Improvements in retinal sensitivity were evident, to varying extents, in six participants for up to 3 years, peaking at 6 to 12 months after treatment and then declining. No associated improvement in retinal function was detected by means of ERG. Three participants had intraocular inflammation, and two had clinically significant deterioration of visual acuity. The reduction in central retinal thickness varied among participants. In dogs, RPE65 gene therapy with the same vector at lower doses improved vision-guided behavior, but only higher doses resulted in improvements in retinal function that were detectable with the use of ERG. CONCLUSIONS Gene therapy with rAAV2/2 RPE65 vector improved retinal sensitivity, albeit modestly and temporarily. Comparison with the results obtained in the dog model indicates that there is a species difference in the amount of RPE65 required to drive the visual cycle and that the demand for RPE65 in affected persons was not met to the extent required for a durable, robust effect. (Funded by the National Institute for Health Research and others; ClinicalTrials.gov number, NCT00643747.).
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Affiliation(s)
- James W B Bainbridge
- From the UCL (University College London) Institute of Ophthalmology (J.W.B.B., M.S.M., V.S., S.J.R., S.E.B., C.R., A.G., F.M.M., S.G.B., P.J.G., V.A.L., K.B., A.V., G.E.H., F.W.F., M.N., A.T.M., M.M., A.S., A.J.S., G.R., R.R.A.) and the Department of Civil, Environmental, and Geomatic Engineering (N.T.), UCL, and Moorfields Eye Hospital (J.W.B.B., M.S.M., V.S., S.J.R., A.G., K.B., G.H., A.M., M.M.), London, and the Department of Psychology, Durham University, Durham (M.N.) - all in the United Kingdom; the College of Veterinary Medicine, Michigan State University, East Lansing (F.M.M., S.M.P.-J.), and the Kellogg Eye Center, University of Michigan Medical School, Ann Arbor (K.L.F., D.A.T., R.R.A.); the Center for Human Genetics, KU Leuven (T.J.L.R.), and the Department of Ophthalmology, UZ Leuven, Campus Sint-Rafaël (I.C.) - both in Leuven, Belgium; Rotterdam Eye Hospital, Rotterdam, the Netherlands (S.Y., L.I.B.); and the Oregon Retinal Degeneration Center, Ophthalmic Genetics Service, Casey Eye Institute, Oregon Health and Science University, Portland (R.G.W.)
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33
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Abstract
The ATP-binding cassette (ABC) transporter gene, ABCA4 (ABCR), was characterized in 1997 as the causal gene for autosomal recessive Stargardt disease (STGD1). Shortly thereafter several other phenotypes were associated with mutations in ABCA4, which now have collectively emerged as the most frequent cause of retinal degeneration phenotypes of Mendelian inheritance. ABCA4 functions as an important transporter (or "flippase") of vitamin A derivatives in the visual cycle. Several ways to alleviate the effects of the defective ABCA4 protein, which cause accumulation of 11-cis and all-trans-retinal in photoreceptors and lipofuscin in the retinal pigment epithelium, have been proposed. Although ABCA4 has proven to be a difficult research target, substantial progress through genetic, functional, and translational studies has allowed major advances in therapeutic applications for ABCA4-associated pathology, which should be available to patients in the (near) future. Here, we summarize the status of the gene therapy-based treatment options of ABCA4-associated diseases.
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Affiliation(s)
| | - Ivana Trapani
- Telethon Institute of Genetics and Medicine, Naples, 80131 Italy
| | - Rando Allikmets
- Department of Ophthalmology, and Department of Pathology and Cell Biology, Columbia University, New York, New York 10032
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34
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Treatment of ocular disorders by gene therapy. Eur J Pharm Biopharm 2014; 95:331-42. [PMID: 25536112 DOI: 10.1016/j.ejpb.2014.12.022] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/08/2014] [Accepted: 12/15/2014] [Indexed: 12/27/2022]
Abstract
Gene therapy to treat ocular disorders is still starting, and current therapies are primarily experimental, with most human clinical trials still in research state, although beginning to show encouraging results. Currently 33 clinical trials have been approved, are in progress, or have been completed. The most promising results have been obtained in clinical trials of ocular gene therapy for Leber Congenital Amaurosis, which have prompted the study of several ocular diseases that are good candidates to be treated with gene therapy: glaucoma, age-related macular degeneration, retinitis pigmentosa, or choroideremia. The success of gene therapy relies on the efficient delivery of the genetic material to target cells, achieving optimum long-term gene expression. Although viral vectors have been widely used, their potential risk associated mainly with immunogenicity and mutagenesis has promoted the design of non-viral vectors. In this review, the main administration routes and the most studied delivery systems, viral and non-viral, for ocular gene therapy are presented. The primary ocular disease candidates to be treated with gene therapy have been also reviewed, including the genetic basis and the most relevant preclinical and clinical studies.
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35
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Trapani I, Puppo A, Auricchio A. Vector platforms for gene therapy of inherited retinopathies. Prog Retin Eye Res 2014; 43:108-28. [PMID: 25124745 PMCID: PMC4241499 DOI: 10.1016/j.preteyeres.2014.08.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/26/2014] [Accepted: 08/02/2014] [Indexed: 12/20/2022]
Abstract
Inherited retinopathies (IR) are common untreatable blinding conditions. Most of them are inherited as monogenic disorders, due to mutations in genes expressed in retinal photoreceptors (PR) and in retinal pigment epithelium (RPE). The retina's compatibility with gene transfer has made transduction of different retinal cell layers in small and large animal models via viral and non-viral vectors possible. The ongoing identification of novel viruses as well as modifications of existing ones based either on rational design or directed evolution have generated vector variants with improved transduction properties. Dozens of promising proofs of concept have been obtained in IR animal models with both viral and non-viral vectors, and some of them have been relayed to clinical trials. To date, recombinant vectors based on the adeno-associated virus (AAV) represent the most promising tool for retinal gene therapy, given their ability to efficiently deliver therapeutic genes to both PR and RPE and their excellent safety and efficacy profiles in humans. However, AAVs' limited cargo capacity has prevented application of the viral vector to treatments requiring transfer of genes with a coding sequence larger than 5 kb. Vectors with larger capacity, i.e. nanoparticles, adenoviral and lentiviral vectors are being exploited for gene transfer to the retina in animal models and, more recently, in humans. This review focuses on the available platforms for retinal gene therapy to fight inherited blindness, highlights their main strengths and examines the efforts to overcome some of their limitations.
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Affiliation(s)
- Ivana Trapani
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Agostina Puppo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy; Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy.
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36
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Rakoczy EP, Narfström K. Gene therapy for eye as regenerative medicine? Lessons from RPE65 gene therapy for Leber's Congenital Amaurosis. Int J Biochem Cell Biol 2014; 56:153-7. [PMID: 25286304 DOI: 10.1016/j.biocel.2014.09.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 09/08/2014] [Accepted: 09/25/2014] [Indexed: 11/15/2022]
Abstract
Recombinant virus mediated gene therapy of Leber's Congenital Amaurosis has provided a wide range of data on the utility of gene replacement therapy for recessive diseases. Studies to date demonstrate that gene therapy in the eye is safe and can result in long-term recovery of visual function, but they also highlight that further research is required to identify optimum intervention time-points, target populations and the compatibility of associate therapies. This article is part of a directed issue entitled: Regenerative Medicine: the challenge of translation.
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Affiliation(s)
- Elizabeth P Rakoczy
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Crawley, 6009, Western Australia, Australia.
| | - Kristina Narfström
- College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
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37
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Rajala A, Wang Y, Zhu Y, Ranjo-Bishop M, Ma JX, Mao C, Rajala RVS. Nanoparticle-assisted targeted delivery of eye-specific genes to eyes significantly improves the vision of blind mice in vivo. NANO LETTERS 2014; 14:5257-63. [PMID: 25115433 PMCID: PMC4160266 DOI: 10.1021/nl502275s] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/29/2014] [Indexed: 05/24/2023]
Abstract
Application of viruses as a carrier, though not safe, to deliver genes to eye tissue was successful. However, a safer, nonviral, biocompatible lipid-based nanoparticle has never been tested to treat blinding eye diseases. We created an artificial virus using a nanoparticle, liposome-protamine-DNA complex (LPD), modified with a cell permeable peptide and a nuclear localization signaling (NLS) peptide, to deliver a functional gene for eye disease treatment. In the eye, a photochemical, 11-cis-retinal, allows the visual pigment rhodopsin to absorb light in the visible range. Without the photochemical, we lose the ability to see light. Retinal pigment epithelium protein 65 (Rpe65) is the key enzyme in regulating the availability of photochemical; deficiency of this gene results in a blinding eye disease. Here we show for the first time that LPD promotes efficient delivery in a cell specific-manner, and a long-term expression of Rpe65 gene to mice lacking Rpe65 gene, leading to in vivo correction of blindness. Thus, LPD nanoparticles could provide a promising, efficient, nonviral method of gene delivery with clinical applications in eye disease treatment.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, Department of Physiology, Department of Cell
Biology, and Dean A. McGee
Eye Institute, University of Oklahoma Health
Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Yuhong Wang
- Department of Ophthalmology, Department of Physiology, Department of Cell
Biology, and Dean A. McGee
Eye Institute, University of Oklahoma Health
Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Ye Zhu
- Department
of Chemistry and Biochemistry, University
of Oklahoma, Stephenson Life Sciences Research Center, Norman, Oklahoma 73019, United States
| | - Michelle Ranjo-Bishop
- Department of Ophthalmology, Department of Physiology, Department of Cell
Biology, and Dean A. McGee
Eye Institute, University of Oklahoma Health
Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Jian-Xing Ma
- Department of Ophthalmology, Department of Physiology, Department of Cell
Biology, and Dean A. McGee
Eye Institute, University of Oklahoma Health
Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Chuanbin Mao
- Department
of Chemistry and Biochemistry, University
of Oklahoma, Stephenson Life Sciences Research Center, Norman, Oklahoma 73019, United States
| | - Raju V. S. Rajala
- Department of Ophthalmology, Department of Physiology, Department of Cell
Biology, and Dean A. McGee
Eye Institute, University of Oklahoma Health
Sciences Center, Oklahoma City, Oklahoma 73104, United States
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38
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Takahashi Y, Moiseyev G, Ma JX. Identification of key residues determining isomerohydrolase activity of human RPE65. J Biol Chem 2014; 289:26743-26751. [PMID: 25112876 DOI: 10.1074/jbc.m114.558619] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
RPE65 is the retinoid isomerohydrolase that converts all-trans-retinyl ester to 11-cis-retinol, a key reaction in the retinoid visual cycle. We have previously reported that cone-dominant chicken RPE65 (cRPE65) shares 90% sequence identity with human RPE65 (hRPE65) but exhibits substantially higher isomerohydrolase activity than that of bovine RPE65 or hRPE65. In this study, we sought to identify key residues responsible for the higher enzymatic activity of cRPE65. Based on the amino acid sequence comparison of mammalian and other lower vertebrates' RPE65, including cone-dominant chicken, 8 residues of hRPE65 were separately replaced by their counterparts of cRPE65 using site-directed mutagenesis. The enzymatic activities of cRPE65, hRPE65, and its mutants were measured by in vitro isomerohydrolase activity assay, and the retinoid products were analyzed by HPLC. Among the mutants analyzed, two single point mutants, N170K and K297G, and a double mutant, N170K/K297G, of hRPE65 exhibited significantly higher catalytic activity than WT hRPE65. Further, when an amino-terminal fragment (Met(1)-Arg(33)) of the N170K/K297G double mutant of hRPE65 was replaced with the corresponding cRPE65 fragment, the isomerohydrolase activity was further increased to a level similar to that of cRPE65. This finding contributes to the understanding of the structural basis for isomerohydrolase activity. This highly efficient human isomerohydrolase mutant can be used to improve the efficacy of RPE65 gene therapy for retinal degeneration caused by RPE65 mutations.
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Affiliation(s)
- Yusuke Takahashi
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Gennadiy Moiseyev
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Department of Physiology, and University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Jian-Xing Ma
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Department of Physiology, and University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104.
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Derivation of traceable and transplantable photoreceptors from mouse embryonic stem cells. Stem Cell Reports 2014; 2:853-65. [PMID: 24936471 PMCID: PMC4050344 DOI: 10.1016/j.stemcr.2014.04.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 01/12/2023] Open
Abstract
Retinal degenerative diseases resulting in the loss of photoreceptors are one of the major causes of blindness. Photoreceptor replacement therapy is a promising treatment because the transplantation of retina-derived photoreceptors can be applied now to different murine retinopathies to restore visual function. To have an unlimited source of photoreceptors, we derived a transgenic embryonic stem cell (ESC) line in which the Crx-GFP transgene is expressed in photoreceptors and assessed the capacity of a 3D culture protocol to produce integration-competent photoreceptors. This culture system allows the production of a large number of photoreceptors recapitulating the in vivo development. After transplantation, integrated cells showed the typical morphology of mature rods bearing external segments and ribbon synapses. We conclude that a 3D protocol coupled with ESCs provides a safe and renewable source of photoreceptors displaying a development and transplantation competence comparable to photoreceptors from age-matched retinas. De novo isolation of Crx-GFP embryonic stem cell lines to trace photoreceptors 3D culture system fine-tuning to generate many integration-competent photoreceptors Revealing in-vitro- and in-vivo-developing retina similarities Characterization of the most appropriate stage to transplant photoreceptors
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40
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Wright CB, Chrenek MA, Feng W, Getz SE, Duncan T, Pardue MT, Feng Y, Redmond TM, Boatright JH, Nickerson JM. The Rpe65 rd12 allele exerts a semidominant negative effect on vision in mice. Invest Ophthalmol Vis Sci 2014; 55:2500-15. [PMID: 24644049 PMCID: PMC3993890 DOI: 10.1167/iovs.13-13574] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/10/2014] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The rd12 mouse was reported as a recessively inherited Rpe65 mutation. We asked if the rd12 mutation resides in Rpe65 and how the mutation manifests itself. METHODS A complementation test was performed by mating Rpe65(KO) (KO/KO) and rd12 mice together to determine if the rd12 mutation is in the Rpe65 gene. Visual function of wild-type (+/+), KO/+, rd12/+, KO/KO, rd12/rd12, and KO/rd12 mice was measured by optokinetic tracking (OKT) and ERG. Morphology was assessed by retinal cross section. qRT-PCR quantified Rpe65 mRNA levels. Immunoblotting measured the size and level of RPE65 protein. Rpe65 mRNA localization was visualized with RNA fluorescence in situ hybridization (FISH). Fractions of Rpe65 mRNA-bound proteins were separated by linear sucrose gradient fractionation. RESULTS The KO and rd12 alleles did not complement. The rd12 allele induced a negative semidominant effect on visual function; OKT responses became undetectable 120 days earlier in rd12/rd12 mice compared with KO/KO mice. rd12/+ mice lost approximately 21% visual acuity by P210. rd12/rd12 mice had fewer cone photoreceptor nuclei than KO/KO mice at P60. rd12/rd12 mice expressed 71% +/+ levels of Rpe65 mRNA, but protein was undetectable. Mutant mRNA was appropriately spliced, exported to the cytoplasm, trafficked, and contained no other coding mutation aside from the known nonsense mutation. Mutant mRNA was enriched on ribosome-free messenger ribonucleoproteins (mRNPs), whereas wild-type mRNA was enriched on actively translating polyribosomes. CONCLUSIONS The rd12 lesion is in Rpe65. The rd12 mutant phenotype inherits in a semidominant manner. The effects of the mutant mRNA on visual function may result from inefficient binding to ribosomes for translation.
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Affiliation(s)
- Charles B. Wright
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Micah A. Chrenek
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Wei Feng
- Department of Pharmacology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Shannon E. Getz
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Todd Duncan
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Machelle T. Pardue
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
- Rehabiliation Research and Development Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia, United States
| | - Yue Feng
- Department of Pharmacology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - T. Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Jeffrey H. Boatright
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - John M. Nickerson
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
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41
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Koirala A, Conley SM, Makkia R, Liu Z, Cooper MJ, Sparrow JR, Naash MI. Persistence of non-viral vector mediated RPE65 expression: case for viability as a gene transfer therapy for RPE-based diseases. J Control Release 2013; 172:745-52. [PMID: 24035979 DOI: 10.1016/j.jconrel.2013.08.299] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 08/22/2013] [Indexed: 11/25/2022]
Abstract
Mutations in the retinal pigment epithelium (RPE) gene RPE65 are associated with multiple blinding diseases including Leber's Congenital Amaurosis (LCA). Our goal has been to develop persistent, effective non-viral genetic therapies to treat this condition. Using precisely engineered DNA vectors and high capacity compacted DNA nanoparticles (NP), we previously demonstrated that both plasmid and NP forms of VMD2-hRPE65-S/MAR improved the disease phenotypes in an rpe65(-/-) model of LCA up to 6 months post-injection (PI), however the duration of this treatment efficacy was not established. Here, we test the ability of these vectors to sustain gene expression and phenotypic improvement for the life of the animal. NPs or naked DNA were subretinally injected in rpe65(-/-) mice at postnatal day (P) 16 and evaluated at 15 months PI. Quantitative real-time PCR (qRT-PCR) and immunofluorescence were performed at PI-15 months and demonstrated appreciable expression of transferred RPE65 (levels were 32% of wild-type [WT] for NPs and 44% of WT for naked DNA). No reduction in expression at the message level was observed from PI-6 month data. Spectral electroretinography (ERG) demonstrated significant improvement in cone ERG amplitudes in treated versus uninjected animals. Most importantly, we also observed reduced fundus autofluorescence in the eyes injected with NP and naked DNA compared to uninjected counterparts. Consistent with these observations, biochemical studies showed a reduction in the accumulation of toxic retinyl esters in treated mice, suggesting that the transferred hRPE65 was functional. These critical results indicate that both NP and uncompacted plasmid VMD2-hRPE65-S/MAR can mediate persistent, long-term improvement in an RPE-associated disease phenotype, and suggest that DNA NPs, which are non-toxic and have a large payload capacity, expand the treatment repertoire available for ocular gene therapy.
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Affiliation(s)
- Adarsha Koirala
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
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Cachafeiro M, Bemelmans AP, Samardzija M, Afanasieva T, Pournaras JA, Grimm C, Kostic C, Philippe S, Wenzel A, Arsenijevic Y. Hyperactivation of retina by light in mice leads to photoreceptor cell death mediated by VEGF and retinal pigment epithelium permeability. Cell Death Dis 2013; 4:e781. [PMID: 23990021 PMCID: PMC3763463 DOI: 10.1038/cddis.2013.303] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/22/2013] [Accepted: 06/17/2013] [Indexed: 11/29/2022]
Abstract
Light toxicity is suspected to enhance certain retinal degenerative processes such as age-related macular degeneration. Death of photoreceptors can be induced by their exposure to the visible light, and although cellular processes within photoreceptors have been characterized extensively, the role of the retinal pigment epithelium (RPE) in this model is less well understood. We demonstrate that exposition to intense light causes the immediate breakdown of the outer blood–retinal barrier (BRB). In a molecular level, we observed the slackening of adherens junctions tying up the RPE and massive leakage of albumin into the neural retina. Retinal pigment epithelial cells normally secrete vascular endothelial growth factor (VEGF) at their basolateral side; light damage in contrast leads to VEGF increase on the apical side – that is, in the neuroretina. Blocking VEGF, by means of lentiviral gene transfer to express an anti-VEGF antibody in RPE cells, inhibits outer BRB breakdown and retinal degeneration, as illustrated by functional, behavioral and morphometric analysis. Our data show that exposure to high levels of visible light induces hyperpermeability of the RPE, likely involving VEGF signaling. The resulting retinal edema contributes to irreversible damage to photoreceptors. These data suggest that anti-VEGF compounds are of therapeutic interest when the outer BRB is altered by retinal stresses.
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Affiliation(s)
- M Cachafeiro
- Unit of Gene Therapy & Stem Cell Biology, Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
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Colella P, Auricchio A. Gene therapy of inherited retinopathies: a long and successful road from viral vectors to patients. Hum Gene Ther 2013; 23:796-807. [PMID: 22734691 DOI: 10.1089/hum.2012.123] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Inherited retinopathies (IRs) are common and untreatable blinding conditions inherited mostly as monogenic due to mutations in genes expressed in retinal photoreceptors (PRs) and in retinal pigment epithelium (RPE). Over the last two decades, the retina has emerged as one of the most favorable target tissues for gene therapy given its small size and its enclosed and immune-privileged environment. Different types of viral vectors have been developed, especially those based on the adeno-associated virus (AAV), which efficiently deliver therapeutic genes to PRs or RPE upon subretinal injections. Dozens of successful proofs of concept of the efficacy of gene therapy for recessive and dominant IRs have been generated in small and large models that have paved the way to the first clinical trials using AAV in patients with Leber congenital amaurosis, a severe form of childhood blindness. The results from these initial trials suggest that retinal gene therapy with AAV is safe in humans, that vision can be improved in patients that have suffered from severe impairment of visual function, in some cases for decades, and that readministration of AAV to the subretinal space is feasible, effective, and safe. However, none of the trials could match the levels of efficacy of gene therapy observed in a dog model of the disease, suggesting that there is room for improvement. In conclusion, these results bode well for further testing of AAV-mediated retinal gene therapy in patients with other monogenic and complex forms of blindness.
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44
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Askou AL, Pournaras JAC, Pihlmann M, Svalgaard JD, Arsenijevic Y, Kostic C, Bek T, Dagnaes-Hansen F, Mikkelsen JG, Jensen TG, Corydon TJ. Reduction of choroidal neovascularization in mice by adeno-associated virus-delivered anti-vascular endothelial growth factor short hairpin RNA. J Gene Med 2013; 14:632-41. [PMID: 23080553 DOI: 10.1002/jgm.2678] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/04/2012] [Accepted: 10/15/2012] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Strategies leading to the long-term suppression of inappropriate ocular angiogenesis are required to avoid the need for repetitive monthly injections for treatment of diseases of the eye, such as age-related macular degeneration (AMD). The present study aimed to develop a strategy for the sustained repression of vascular endothelial growth factor (VEGF), which is identified as the key player in exudative AMD. METHODS We have employed short hairpin (sh)RNAs combined with adeno-associated virus (AAV) delivery to obtain the targeted expression of potent gene-regulatory molecules. Anti-VEGF shRNAs were analyzed in human retinal pigment epithelial (RPE) cells using Renilla luciferase screening. For in vivo delivery of the most potent shRNA, self-complementary AAV vectors were packaged in serotype 8 capsids (scAAV2/8-hU6-sh9). In vivo efficacy was evaluated either by injection of scAAV2/8-hU6-sh9 into murine hind limb muscles or in a laser-induced murine model of choroidal neovascularization (CNV) following scAAV2/8-hU6-sh9 subretinal delivery. RESULTS Plasmids encoding anti-VEGF shRNAs showed efficient knockdown of human VEGF in RPEs. Intramuscular administration led to localized expression and 91% knockdown of endogenous murine (m)VEGF. Subsequently, the ability of AAV2/8-encoded shRNAs to impair vessel formation was evaluated in the murine model of CNV. In this model, the sizes of the CNV were significantly reduced (up to 48%) following scAAV2/8-hU6-sh9 subretinal delivery. CONCLUSIONS Using anti-VEGF vectors, we have demonstrated efficient silencing of endogenous mVEGF and showed that subretinal administration of scAAV2/8-hU6-sh9 has the ability to impair vessel formation in an AMD animal model. Thus, AAV-encoded shRNA can be used for the inhibition of neovascularization, leading to the development of sustained anti-VEGF therapy.
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45
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Boye SE, Boye SL, Lewin AS, Hauswirth WW. A comprehensive review of retinal gene therapy. Mol Ther 2013; 21:509-19. [PMID: 23358189 DOI: 10.1038/mt.2012.280] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Blindness, although not life threatening, is a debilitating disorder for which few, if any treatments exist. Ocular gene therapies have the potential to profoundly improve the quality of life in patients with inherited retinal disease. As such, tremendous focus has been given to develop such therapies. Several factors make the eye an ideal organ for gene-replacement therapy including its accessibility, immune privilege, small size, compartmentalization, and the existence of a contralateral control. This review will provide a comprehensive summary of (i) existing gene therapy clinical trials for several genetic forms of blindness and (ii) preclinical efficacy and safety studies in a variety of animal models of retinal disease which demonstrate strong potential for clinical application. To be as comprehensive as possible, we include additional proof of concept studies using gene replacement, neurotrophic/neuroprotective, optogenetic, antiangiogenic, or antioxidative stress strategies as well as a description of the current challenges and future directions in the ocular gene therapy field to this review as a supplement.
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Affiliation(s)
- Shannon E Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA.
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Retinal degeneration depends on Bmi1 function and reactivation of cell cycle proteins. Proc Natl Acad Sci U S A 2013; 110:E593-601. [PMID: 23359713 DOI: 10.1073/pnas.1108297110] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The epigenetic regulator Bmi1 controls proliferation in many organs. Reexpression of cell cycle proteins such as cyclin-dependent kinases (CDKs) is a hallmark of neuronal apoptosis in neurodegenerative diseases. Here we address the potential role of Bmi1 as a key regulator of cell cycle proteins during neuronal apoptosis. We show that several cell cycle proteins are expressed in different models of retinal degeneration and required in the Rd1 photoreceptor death process. Deleting E2f1, a downstream target of CDKs, provided temporary protection in Rd1 mice. Most importantly, genetic ablation of Bmi1 provided extensive photoreceptor survival and improvement of retinal function in Rd1 mice, mediated by a decrease in cell cycle markers and regulators independent of p16(Ink4a) and p19(Arf). These data reveal that Bmi1 controls the cell cycle-related death process, highlighting this pathway as a promising therapeutic target for neuroprotection in retinal dystrophies.
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Human retinal gene therapy for Leber congenital amaurosis shows advancing retinal degeneration despite enduring visual improvement. Proc Natl Acad Sci U S A 2013; 110:E517-25. [PMID: 23341635 DOI: 10.1073/pnas.1218933110] [Citation(s) in RCA: 328] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Leber congenital amaurosis (LCA) associated with retinal pigment epithelium-specific protein 65 kDa (RPE65) mutations is a severe hereditary blindness resulting from both dysfunction and degeneration of photoreceptors. Clinical trials with gene augmentation therapy have shown partial reversal of the dysfunction, but the effects on the degeneration are not known. We evaluated the consequences of gene therapy on retinal degeneration in patients with RPE65-LCA and its canine model. In untreated RPE65-LCA patients, there was dysfunction and degeneration of photoreceptors, even at the earliest ages. Examined serially over years, the outer photoreceptor nuclear layer showed progressive thinning. Treated RPE65-LCA showed substantial visual improvement in the short term and no detectable decline from this new level over the long term. However, retinal degeneration continued to progress unabated. In RPE65-mutant dogs, the first one-quarter of their lifespan showed only dysfunction, and there was normal outer photoreceptor nuclear layer thickness retina-wide. Dogs treated during the earlier dysfunction-only stage showed improved visual function and dramatic protection of treated photoreceptors from degeneration when measured 5-11 y later. Dogs treated later during the combined dysfunction and degeneration stage also showed visual function improvement, but photoreceptor loss continued unabated, the same as in human RPE65-LCA. The results suggest that, in RPE65 disease treatment, protection from visual function deterioration cannot be assumed to imply protection from degeneration. The effects of gene augmentation therapy are complex and suggest a need for a combinatorial strategy in RPE65-LCA to not only improve function in the short term but also slow retinal degeneration in the long term.
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Koirala A, Makkia RS, Conley SM, Cooper MJ, Naash MI. S/MAR-containing DNA nanoparticles promote persistent RPE gene expression and improvement in RPE65-associated LCA. Hum Mol Genet 2013; 22:1632-42. [PMID: 23335596 DOI: 10.1093/hmg/ddt013] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mutations in genes in the retinal pigment epithelium (RPE) cause or contribute to debilitating ocular diseases, including Leber's congenital amaurosis (LCA). Genetic therapies, particularly adeno-associated viruses (AAVs), are a popular choice for monogenic diseases; however, the limited payload capacity of AAVs combined with the large number of retinal disease genes exceeding that capacity make the development of alternative delivery methods critical. Here, we test the ability of compacted DNA nanoparticles (NPs) containing a plasmid with a scaffold matrix attachment region (S/MAR) and vitelliform macular dystrophy 2 (VMD2) promoter to target the RPE, drive long-term, tissue-specific gene expression and mediate proof-of-principle rescue in the rpe65(-/-) model of LCA. We show that the S/MAR-containing plasmid exhibited reporter gene expression levels several fold higher than plasmid or NPs without S/MARs. Importantly, this expression was highly persistent, lasting up to 2 years (last timepoint studied). We therefore selected this plasmid for testing in the rpe65(-/-) mouse model and observe that NP or plasmid VMD2-hRPE65-S/MAR led to structural and functional improvements in the LCA disease phenotype. These results indicate that the non-viral delivery of hRPE65 vectors can result in persistent, therapeutically efficacious gene expression in the RPE.
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Affiliation(s)
- Adarsha Koirala
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
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Mowat FM, Breuwer AR, Bartoe JT, Annear MJ, Zhang Z, Smith AJ, Bainbridge JWB, Petersen-Jones SM, Ali RR. RPE65 gene therapy slows cone loss in Rpe65-deficient dogs. Gene Ther 2012; 20:545-55. [PMID: 22951453 DOI: 10.1038/gt.2012.63] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent clinical trials of retinal pigment epithelium gene (RPE65) supplementation therapy in Leber congenital amaurosis type 2 patients have demonstrated improvements in rod and cone function, but it may be some years before the effects of therapy on photoreceptor survival become apparent. The Rpe65-deficient dog is a very useful pre-clinical model in which to test efficacy of therapies, because the dog has a retina with a high degree of similarity to that of humans. In this study, we evaluated the effect of RPE65 gene therapy on photoreceptor survival in order to predict the potential benefit and limitations of therapy in patients. We examined the retinas of Rpe65-deficient dogs after RPE65 gene therapy to evaluate the preservation of rods and cone photoreceptor subtypes. We found that gene therapy preserves both rods and cones. While the moderate loss of rods in the Rpe65-deficient dog retina is slowed by gene therapy, S-cones are lost extensively and gene therapy can prevent that loss, although only within the treated area. Although LM-cones are not lost extensively, cone opsin mislocalization indicates that they are stressed, and this can be partially reversed by gene therapy. Our results suggest that gene therapy may be able to slow cone degeneration in patients if intervention is sufficiently early and also that it is probably important to treat the macula in order to preserve central function.
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Affiliation(s)
- F M Mowat
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
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Abstract
Despite the first application of gene therapy in 1990, gene therapy has until recently failed to meet the huge expectations set forth by researchers, clinicians, and patients, thus dampening enthusiasm for an imminent cure for many life-threatening genetic diseases. Nonetheless, in recent years we have witnessed a strong comeback for gene therapy, with clinical successes in young and adult subjects suffering from inherited forms of blindness or from X-linked severe combined immunodeficiency disease. In this review, various gene therapy vectors progressing into clinical development and pivotal advances in gene therapy trials will be discussed.
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Affiliation(s)
- Maria P Limberis
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104-3403, USA.
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