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Du W, Li J, Tang X, Yu W, Zhao M. CRISPR/SaCas9-based gene editing rescues photoreceptor degeneration throughout a rhodopsin-associated autosomal dominant retinitis pigmentosa mouse model. Exp Biol Med (Maywood) 2023; 248:1818-1828. [PMID: 37837380 PMCID: PMC10792415 DOI: 10.1177/15353702231199069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 08/12/2023] [Indexed: 10/16/2023] Open
Abstract
Rhodopsin (Rho) gene mutation was considered the highest prevalent mutation in autosomal dominant retinitis pigmentosa (ADRP); however, effective therapeutics for ADRP have not been developed. The process of gene editing via the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system offers the potentiality to provide cures for dominantly inherited disorders. Herein, we generated a CRISPR/SaCas9-mediated gene reduction system to inactivate the Rho mutant, while replacing normal rhodopsin in a rhodopsin mutation mouse model. When Rho-P23H knock-in mice were administered a subretinal injection of the "reduction and replacement" system, the expression of mutant rhodopsin was reduced, and retinal function was improved. Therefore, we concluded that CRISPR/SaCas9-based "reduction and replacement" gene therapy could provide structural and functional benefits for Rho mutant ADRP, as well as new directions for future clinical research on the treatment of such gain-of-function genetic diseases.
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Affiliation(s)
- Wei Du
- Department of Ophthalmology and Clinical Centre of Optometry, Peking University People’s Hospital, Beijing 100044, China
- Eye Diseases and Optometry Institute, Peking University People’s Hospital, Beijing 100044, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing 100044, China
- College of Optometry, Peking University Health Science Center, Beijing 100044, China
| | - Jiarui Li
- Department of Ophthalmology and Clinical Centre of Optometry, Peking University People’s Hospital, Beijing 100044, China
- Eye Diseases and Optometry Institute, Peking University People’s Hospital, Beijing 100044, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing 100044, China
- College of Optometry, Peking University Health Science Center, Beijing 100044, China
| | - Xin Tang
- Department of Ophthalmology and Clinical Centre of Optometry, Peking University People’s Hospital, Beijing 100044, China
- Eye Diseases and Optometry Institute, Peking University People’s Hospital, Beijing 100044, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing 100044, China
- College of Optometry, Peking University Health Science Center, Beijing 100044, China
| | - Wenzhen Yu
- Department of Ophthalmology and Clinical Centre of Optometry, Peking University People’s Hospital, Beijing 100044, China
- Eye Diseases and Optometry Institute, Peking University People’s Hospital, Beijing 100044, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing 100044, China
- College of Optometry, Peking University Health Science Center, Beijing 100044, China
| | - Mingwei Zhao
- Department of Ophthalmology and Clinical Centre of Optometry, Peking University People’s Hospital, Beijing 100044, China
- Eye Diseases and Optometry Institute, Peking University People’s Hospital, Beijing 100044, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing 100044, China
- College of Optometry, Peking University Health Science Center, Beijing 100044, China
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2
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Ahmed CM, Massengill MT, Ildefonso CJ, Jalligampala A, Zhu P, Li H, Patel AP, McCall MA, Lewin AS. Binocular benefit following monocular subretinal AAV injection in a mouse model of autosomal dominant retinitis pigmentosa (adRP). Vision Res 2023; 206:108189. [PMID: 36773475 DOI: 10.1016/j.visres.2023.108189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 02/11/2023]
Abstract
Autosomal dominant retinitis pigmentosa (adRP) is frequently caused by mutations in RHO, the gene for rhodopsin. In previous experiments in dogs with the T4R mutation in RHO, an AAV2/5 vector expressing an shRNA directed to human and dog RHO mRNA and an shRNA-resistant human RHO cDNA (AAV-RHO820-shRNA820) prevented retinal degeneration for more than eight months following injection. It is crucial, however, to determine if this RNA replacement vector acts in a mutation-independent and species-independent manner. We, therefore, injected mice transgenic for human P23H RHO with this vector unilaterally at postnatal day 30. We monitored their retinal structure by using spectral-domain optical coherence tomography (SD-OCT) and retinal function using electroretinography (ERG) for nine months. We compared these to P23H RHO transgenic mice injected unilaterally with a control vector. Though retinas continued to thin over time, compared to control injected eyes, treatment with AAV-RHO820-shRNA820 slowed the loss of photoreceptor cells and the decrease in ERG amplitudes during the nine-month study period. Unexpectedly, we also observed the preservation of retinal structure and function in the untreated contralateral eyes of AAV-RHO820-shRNA820 treated mice. PCR analysis and western blots showed that a low amount of vector from injected eyes was present in uninjected eyes. In addition, protective neurotrophic factors bFGF and GDNF were elevated in both eyes of treated mice. Our finding suggests that using this or similar RNA replacement vectors in human gene therapy may provide clinical benefit to both eyes of patients with adRP.
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Affiliation(s)
- Chulbul M Ahmed
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Michael T Massengill
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | | | - Archana Jalligampala
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USA
| | - Ping Zhu
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Hong Li
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Anil P Patel
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Maureen A McCall
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USA
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA.
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3
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Lewin AS, Smith WC. Gene Therapy for Rhodopsin Mutations. Cold Spring Harb Perspect Med 2022; 12:a041283. [PMID: 35940643 PMCID: PMC9435570 DOI: 10.1101/cshperspect.a041283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mutations in RHO, the gene for rhodopsin, account for a large fraction of autosomal-dominant retinitis pigmentosa (adRP). Patients fall into two clinical classes, those with early onset, pan retinal photoreceptor degeneration, and those who experience slowly progressive disease. The latter class of patients are candidates for photoreceptor-directed gene therapy, while former may be candidates for delivery of light-responsive proteins to interneurons or retinal ganglion cells. Gene therapy for RHO adRP may be targeted to the mutant gene at the DNA or RNA level, while other therapies preserve the viability of photoreceptors without addressing the underlying mutation. Correcting the RHO gene and replacing the mutant RNA show promise in animal models, while sustaining viable photoreceptors has the potential to delay the loss of central vision and may preserve photoreceptors for gene-directed treatments.
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Affiliation(s)
- Alfred S Lewin
- Departments of Molecular Genetics and Microbiology and Ophthalmology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - W Clay Smith
- Departments of Molecular Genetics and Microbiology and Ophthalmology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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4
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Massengill MT, Lewin AS. Gene Therapy for Rhodopsin-associated Autosomal Dominant Retinitis Pigmentosa. Int Ophthalmol Clin 2021; 61:79-96. [PMID: 34584046 PMCID: PMC8478325 DOI: 10.1097/iio.0000000000000383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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5
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Patrizi C, Llado M, Benati D, Iodice C, Marrocco E, Guarascio R, Surace EM, Cheetham ME, Auricchio A, Recchia A. Allele-specific editing ameliorates dominant retinitis pigmentosa in a transgenic mouse model. Am J Hum Genet 2021; 108:295-308. [PMID: 33508235 PMCID: PMC7896132 DOI: 10.1016/j.ajhg.2021.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/08/2021] [Indexed: 12/11/2022] Open
Abstract
Retinitis pigmentosa (RP) is a group of progressive retinal degenerations of mostly monogenic inheritance, which cause blindness in about 1:3,500 individuals worldwide. Heterozygous variants in the rhodopsin (RHO) gene are the most common cause of autosomal dominant RP (adRP). Among these, missense variants at C-terminal proline 347, such as p.Pro347Ser, cause severe adRP recurrently in European affected individuals. Here, for the first time, we use CRISPR/Cas9 to selectively target the p.Pro347Ser variant while preserving the wild-type RHO allele in vitro and in a mouse model of adRP. Detailed in vitro, genomic, and biochemical characterization of the rhodopsin C-terminal editing demonstrates a safe downregulation of p.Pro347Ser expression leading to partial recovery of photoreceptor function in a transgenic mouse model treated with adeno-associated viral vectors. This study supports the safety and efficacy of CRISPR/Cas9-mediated allele-specific editing and paves the way for a permanent and precise correction of heterozygous variants in dominantly inherited retinal diseases.
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Affiliation(s)
- Clarissa Patrizi
- Centre for Regenerative Medicine, Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Manel Llado
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Daniela Benati
- Centre for Regenerative Medicine, Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Carolina Iodice
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Elena Marrocco
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | | | - Enrico M Surace
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; Medical Genetics, Department of Translational Medicine, Federico II University, 80125 Naples, Italy
| | | | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; Medical Genetics, Department of Advanced Biomedicine, Federico II University, 80125 Naples, Italy.
| | - Alessandra Recchia
- Centre for Regenerative Medicine, Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.
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Bucher K, Rodríguez-Bocanegra E, Dauletbekov D, Fischer MD. Immune responses to retinal gene therapy using adeno-associated viral vectors - Implications for treatment success and safety. Prog Retin Eye Res 2020; 83:100915. [PMID: 33069860 DOI: 10.1016/j.preteyeres.2020.100915] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/08/2020] [Accepted: 10/10/2020] [Indexed: 02/06/2023]
Abstract
Recombinant adeno-associated virus (AAV) is the leading vector for gene therapy in the retina. As non-pathogenic, non-integrating, replication deficient vector, the recombinant virus efficiently transduces all key retinal cell populations. Successful testing of AAV vectors in clinical trials of inherited retinal diseases led to the recent approval of voretigene neparvovec (Luxturna) for the treatment of RPE65 mutation-associated retinal dystrophies. However, studies applying AAV-mediated retinal gene therapy independently reported intraocular inflammation and/or loss of efficacy after initial functional improvements. Both observations might be explained by targeted removal of transduced cells via anti-viral defence mechanisms. AAV has been shown to activate innate pattern recognition receptors (PRRs) such as toll-like receptor (TLR)-2 and TLR-9 resulting in the release of inflammatory cytokines and type I interferons. The vector can also induce capsid-specific and transgene-specific T cell responses and neutralizing anti-AAV antibodies which both limit the therapeutic effect. However, the target organ of retinal gene therapy, the eye, is known as an immune-privileged site. It is characterized by suppression of inflammation and promotion of immune tolerance which might prevent AAV-induced immune responses. This review evaluates AAV-related immune responses, toxicity and inflammation in studies of retinal gene therapy, identifies influencing variables of these responses and discusses potential strategies to modulate immune reactions to AAV vectors to increase the safety and efficacy of ocular gene therapy.
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Affiliation(s)
- Kirsten Bucher
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Eduardo Rodríguez-Bocanegra
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Daniyar Dauletbekov
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - M Dominik Fischer
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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7
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Talib M, Boon CJF. Retinal Dystrophies and the Road to Treatment: Clinical Requirements and Considerations. Asia Pac J Ophthalmol (Phila) 2020; 9:159-179. [PMID: 32511120 PMCID: PMC7299224 DOI: 10.1097/apo.0000000000000290] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/01/2020] [Indexed: 12/15/2022] Open
Abstract
: Retinal dystrophies (RDs) comprise relatively rare but devastating causes of progressive vision loss. They represent a spectrum of diseases with marked genetic and clinical heterogeneity. Mutations in the same gene may lead to different diagnoses, for example, retinitis pigmentosa or cone dystrophy. Conversely, mutations in different genes may lead to the same phenotype. The age at symptom onset, and the rate and characteristics of peripheral and central vision decline, may vary widely per disease group and even within families. For most RD cases, no effective treatment is currently available. However, preclinical studies and phase I/II/III gene therapy trials are ongoing for several RD subtypes, and recently the first retinal gene therapy has been approved by the US Food and Drug Administration for RPE65-associated RDs: voretigene neparvovec-rzyl (Luxturna). With the rapid advances in gene therapy studies, insight into the phenotypic spectrum and long-term disease course is crucial information for several RD types. The vast clinical heterogeneity presents another important challenge in the evaluation of potential efficacy in future treatment trials, and in establishing treatment candidacy criteria. This perspective describes these challenges, providing detailed clinical descriptions of several forms of RD that are caused by genes of interest for ongoing and future gene or cell-based therapy trials. Several ongoing and future treatment options will be described.
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Affiliation(s)
- Mays Talib
- Department of Ophthalmology, Leiden, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden, The Netherlands
- Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, University of Amsterdam. Amsterdam, The Netherlands
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8
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Yau EH, Taggart RT, Zuber M, Trujillo AJ, Fayazi ZS, Butler MC, Sheflin LG, Breen JB, Yu D, Sullivan JM. Systematic Screening, Rational Development, and Initial Optimization of Efficacious RNA Silencing Agents for Human Rod Opsin Therapeutics. Transl Vis Sci Technol 2019; 8:28. [PMID: 31853424 PMCID: PMC6908138 DOI: 10.1167/tvst.8.6.28] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 07/15/2019] [Indexed: 12/13/2022] Open
Abstract
Purpose To systematically evaluate human rod opsin (hRHO) mRNA for potential target sites sensitive to posttranscriptional gene silencing (PTGS) by hammerhead ribozyme (hhRz) or RNA interference (RNAi) in human cells. To develop a comprehensive strategy to identify and optimize lead candidate agents for PTGS gene therapeutics. Methods In multidisciplinary RNA drug discovery, computational mRNA accessibility and in vitro experimental methods using reverse transcription–polymerase chain reaction (RT-PCR) were used to map accessibility in full-length hRHO transcripts. HhRzs targeted predicted accessible and inaccessible sites and were screened for cellular knockdown using a bicistronic reporter construct. Lead hhRz and RNAi PTGS agents were rationally optimized for target knockdown in human cells. Results Systematic screening of hRHO mRNA targeting agents resulted in lead candidate identification of a novel hhRz embedded in an RNA scaffold. Rational optimization strategies identified a minimal 725 hhRz as the most active agent. Recently identified tertiary accessory elements did not enhance activity. A 725-short-hairpin RNA (shRNA) agent exerts log-order knockdown. Silent modulation of the 725-hhRz target site in hRHO mRNA resulted in resistance to knockdown. Conclusions Combining rational RNA drug design with cell-based screening allowed rapid identification of lead agents targeting hRHO. Optimization strategies identified the agent with highest intracellular activity. These agents have therapeutic potential in a mutation-independent strategy for adRP, or other degenerations where hRHO is a target. This approach can be broadly applied to any validated target mRNA, regardless of the disease. Translational Relevance This work establishes a platform approach to develop RNA biologicals for the treatment of human disease.
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Affiliation(s)
- Edwin H Yau
- Department of Pharmacology/Toxicology, University at Buffalo-SUNY, Buffalo, NY, USA.,Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA.,Current affiliation: Department of Medicine, Department of Cancer Genetics and Genomics, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Robert T Taggart
- Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA
| | - Mohammed Zuber
- Research Service, VA Western New York Healthcare System, Buffalo, NY, USA.,Current affiliation: Biologist, Office of Pesticide Programs, Environmental Protection Agency, Arlington, VA, USA
| | - Alexandria J Trujillo
- Department of Pharmacology/Toxicology, University at Buffalo-SUNY, Buffalo, NY, USA.,Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA
| | - Zahra S Fayazi
- Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA
| | - Mark C Butler
- Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA.,Research Service, VA Western New York Healthcare System, Buffalo, NY, USA.,Current affiliation: Custom ColLABorators, Buffalo, NY, USA
| | - Lowell G Sheflin
- Department of Pharmacology/Toxicology, University at Buffalo-SUNY, Buffalo, NY, USA
| | - Jennifer B Breen
- Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA.,Current affiliation: Research Analyst II, Athenex, Buffalo, NY, USA
| | - Dian Yu
- Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA.,Current affiliation: Washington National Eye Center, Medstar Georgetown University Hospital/Medstar Washington Hospital, Washington, DC, USA
| | - Jack M Sullivan
- Department of Pharmacology/Toxicology, University at Buffalo-SUNY, Buffalo, NY, USA.,Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY, USA.,Research Service, VA Western New York Healthcare System, Buffalo, NY, USA.,Department of Physiology/Biophysics, University at Buffalo-SUNY, Buffalo, NY, USA.,Neuroscience Program, University at Buffalo-SUNY, Buffalo, NY, USA.,SUNY Eye Institute, Albany, NY, USA.,RNA Institute at University at Albany-SUNY, Albany, NY, USA
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9
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Gene Therapy in Retinal Dystrophies. Int J Mol Sci 2019; 20:ijms20225722. [PMID: 31739639 PMCID: PMC6888000 DOI: 10.3390/ijms20225722] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/13/2019] [Accepted: 11/13/2019] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal dystrophies (IRDs) are a group of clinically and genetically heterogeneous degenerative disorders. To date, mutations have been associated with IRDs in over 270 disease genes, but molecular diagnosis still remains elusive in about a third of cases. The methodologic developments in genome sequencing techniques that we have witnessed in this last decade have represented a turning point not only in diagnosis and prognosis but, above all, in the identification of new therapeutic perspectives. The discovery of new disease genes and pathogenetic mechanisms underlying IRDs has laid the groundwork for gene therapy approaches. Several clinical trials are ongoing, and the recent approval of Luxturna, the first gene therapy product for Leber congenital amaurosis, marks the beginning of a new era. Due to its anatomical and functional characteristics, the retina is the organ of choice for gene therapy, although there are quite a few difficulties in the translational approaches from preclinical models to humans. In the first part of this review, an overview of the current knowledge on methodological issues and future perspectives of gene therapy applied to IRDs is discussed; in the second part, the state of the art of clinical trials on the gene therapy approach in IRDs is illustrated.
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10
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Ludwig PE, Freeman SC, Janot AC. Novel stem cell and gene therapy in diabetic retinopathy, age related macular degeneration, and retinitis pigmentosa. Int J Retina Vitreous 2019; 5:7. [PMID: 30805203 PMCID: PMC6373096 DOI: 10.1186/s40942-019-0158-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/28/2019] [Indexed: 02/07/2023] Open
Abstract
Degenerative retinal disease leads to significant visual morbidity worldwide. Diabetic retinopathy and macular degeneration are leading causes of blindness in the developed world. While current therapies for these diseases slow disease progression, stem cell and gene therapy may also reverse the effects of these, and other, degenerative retinal conditions. Novel therapies being investigated include the use of various types of stem cells in the regeneration of atrophic or damaged retinal tissue, the prolonged administration of neurotrophic factors and/or drug delivery, immunomodulation, as well as the replacement of mutant genes, and immunomodulation through viral vector delivery. This review will update the reader on aspects of stem cell and gene therapy in diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa and other less common inherited retinal dystrophies. These therapies include the use of adeno-associated viral vector-based therapies for treatment of various types of retinitis pigmentosa and dry age-related macular degeneration. Other potential therapies reviewed include the use of mesenchymal stem cells in local immunomodulation, and the use of stem cells in generating structures like three-dimensional retinal sheets for transplantation into degenerative retinas. Finally, aspects of stem cell and gene therapy in diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, and other less common inherited retinal dystrophies will be reviewed.
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Affiliation(s)
- Parker E Ludwig
- 1Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178 USA
| | - S Caleb Freeman
- 1Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178 USA
| | - Adam C Janot
- Vitreoretinal Institute, 7698 Goodwood Blvd, Baton Rouge, LA 70806 USA.,3Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA USA
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11
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Trujillo AJ, Myers JM, Fayazi ZS, Butler MC, Sullivan JM. A Discovery with Potential to Revitalize Hammerhead Ribozyme Therapeutics for Treatment of Inherited Retinal Degenerations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:119-124. [PMID: 31884599 PMCID: PMC7029959 DOI: 10.1007/978-3-030-27378-1_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hammerhead ribozymes (hhRzs), RNA enzymes capable of site-specific cleavage of arbitrary target mRNAs, have faced significant hurdles in development and optimization as gene therapeutics for clinical translation. Chemical and biological barriers must be overcome to realize an effective therapeutic. A new Facilitated ribozyme has been identified with greatly enhanced kinetic properties that lead new insight on the capacity of ribozymes to target mutant genes to treat inherited retinal degenerations.
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Affiliation(s)
- Alexandria J Trujillo
- Research Service, VA Western NY Healthcare System, Departments of Ophthalmology (Ross Eye Institute), Pharmacology/Toxicology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, USA
| | - Jason M Myers
- Research Service, VA Western NY Healthcare System, Department of Ophthalmology (Ross Eye Institute), University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, USA
| | - Zahra S Fayazi
- Research Service, VA Western NY Healthcare System, Department of Ophthalmology (Ross Eye Institute), University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, USA
| | - Mark C Butler
- Research Service, VA Western NY Healthcare System, Department of Ophthalmology (Ross Eye Institute), University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, USA
| | - Jack M Sullivan
- Research Service, VA Western NY Healthcare System, Departments of Ophthalmology (Ross Eye Institute), Pharmacology/Toxicology, Physiology/Biophysics, Program in Neuroscience, Buffalo, NY, USA.
- University at Buffalo-SUNY, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, USA.
- SUNY Eye Institute, Syracuse, NY, USA.
- RNA Institute (SUNY Albany), Albany, NY, USA.
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12
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Progress in Gene Therapy for Rhodopsin Autosomal Dominant Retinitis Pigmentosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:113-118. [PMID: 31884598 DOI: 10.1007/978-3-030-27378-1_19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This brief review summarizes the major proof-of-concept gene therapy studies for autosomal dominant retinitis pigmentosa (RP) caused by mutations in the rhodopsin gene (RHO-adRP) that have been conducted over the past 20 years in various animal models. We have listed in tabular form the various approaches, gene silencing reagents, gene delivery strategies, and salient results from these studies.
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13
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Khabou H, Cordeau C, Pacot L, Fisson S, Dalkara D. Dosage Thresholds and Influence of Transgene Cassette in Adeno-Associated Virus-Related Toxicity. Hum Gene Ther 2018; 29:1235-1241. [PMID: 30132368 DOI: 10.1089/hum.2018.144] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Today, there are >500 published studies and 40 clinical trials to treat retinal disorders using gene therapy. The great majority of them rely on the use of adeno-associated virus vectors (AAV) for therapeutic gene delivery. Thus far, AAVs have an excellent safety profile in the clinic. Nevertheless, it is known that AAV-mediated gene delivery leads to toxicity at higher input doses in experimental gene therapy. This study reveals the factors that contribute to retinal toxicity after subretinal administration of AAV vectors in wild-type mice. The study shows that alongside the input dose, the nature of the transgene and the cells mediating the expression determine the extent of toxicity. Importantly, the study shows that AAV vectors encoding green fluorescent protein (GFP) used as controls in experimental gene therapy are toxic at doses as low as 5 × 109 vg, confounding the observed therapeutic effect in gene therapy paradigms. Altogether, the data show the importance of reducing input doses while increasing transgene expression levels via the use of more efficient capsids and promoters in order to avoid side effects in AAV-mediated gene therapy. Furthermore, the toxicity observed with AAV-GFP vectors imply a reinterpretation of previous gene therapy studies where the therapeutic effect was measured in relation to this control.
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Affiliation(s)
- Hanen Khabou
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Chloé Cordeau
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Laure Pacot
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Sylvain Fisson
- 2 Généthon, Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Deniz Dalkara
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
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14
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Tsai YT, Wu WH, Lee TT, Wu WP, Xu CL, Park KS, Cui X, Justus S, Lin CS, Jauregui R, Su PY, Tsang SH. Clustered Regularly Interspaced Short Palindromic Repeats-Based Genome Surgery for the Treatment of Autosomal Dominant Retinitis Pigmentosa. Ophthalmology 2018; 125:1421-1430. [PMID: 29759820 PMCID: PMC6109419 DOI: 10.1016/j.ophtha.2018.04.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/29/2018] [Accepted: 04/02/2018] [Indexed: 01/02/2023] Open
Abstract
PURPOSE To develop a universal gene therapy to overcome the genetic heterogeneity in retinitis pigmentosa (RP) resulting from mutations in rhodopsin (RHO). DESIGN Experimental study for a combination gene therapy that uses both gene ablation and gene replacement. PARTICIPANTS This study included 2 kinds of human RHO mutation knock-in mouse models: RhoP23H and RhoD190N. In total, 23 RhoP23H/P23H, 43 RhoP23H/+, and 31 RhoD190N/+ mice were used for analysis. METHODS This study involved gene therapy using dual adeno-associated viruses (AAVs) that (1) destroy expression of the endogenous Rho gene in a mutation-independent manner via an improved clustered regularly interspaced short palindromic repeats-based gene deletion and (2) enable expression of wild-type protein via exogenous cDNA. MAIN OUTCOME MEASURES Electroretinographic and histologic analysis. RESULTS The thickness of the outer nuclear layer (ONL) after the subretinal injection of combination ablate-and-replace gene therapy was approximately 17% to 36% more than the ONL thickness resulting from gene replacement-only therapy at 3 months after AAV injection. Furthermore, electroretinography results demonstrated that the a and b waves of both RhoP23H and RhoD190N disease models were preserved more significantly using ablate-and-replace gene therapy (P < 0.001), but not by gene replacement monotherapy. CONCLUSIONS As a proof of concept, our results suggest that the ablate-and-replace strategy can ameliorate disease progression as measured by photoreceptor structure and function for both of the human mutation knock-in models. These results demonstrate the potency of the ablate-and-replace strategy to treat RP caused by different Rho mutations. Furthermore, because ablate-and-replace treatment is mutation independent, this strategy may be used to treat a wide array of dominant diseases in ophthalmology and other fields. Clinical trials using ablate-and-replace gene therapy would allow researchers to determine if this strategy provides any benefits for patients with diseases of interest.
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Affiliation(s)
- Yi-Ting Tsai
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York; Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Wen-Hsuan Wu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Ting-Ting Lee
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Wei-Pu Wu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Christine L Xu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Karen S Park
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Xuan Cui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Sally Justus
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Chyuan-Sheng Lin
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York
| | - Ruben Jauregui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York; Weill Cornell Medical College, New York, New York
| | - Pei-Yin Su
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York; Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, New York; Department of Ophthalmology, Edward S. Harkness Eye Institute, New York Presbyterian Hospital, New York, New York.
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15
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Mutation-independent rhodopsin gene therapy by knockdown and replacement with a single AAV vector. Proc Natl Acad Sci U S A 2018; 115:E8547-E8556. [PMID: 30127005 DOI: 10.1073/pnas.1805055115] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Inherited retinal degenerations are caused by mutations in >250 genes that affect photoreceptor cells or the retinal pigment epithelium and result in vision loss. For autosomal recessive and X-linked retinal degenerations, significant progress has been achieved in the field of gene therapy as evidenced by the growing number of clinical trials and the recent commercialization of the first gene therapy for a form of congenital blindness. However, despite significant efforts to develop a treatment for the most common form of autosomal dominant retinitis pigmentosa (adRP) caused by >150 mutations in the rhodopsin (RHO) gene, translation to the clinic has stalled. Here, we identified a highly efficient shRNA that targets human (and canine) RHO in a mutation-independent manner. In a single adeno-associated viral (AAV) vector we combined this shRNA with a human RHO replacement cDNA made resistant to RNA interference and tested this construct in a naturally occurring canine model of RHO-adRP. Subretinal vector injections led to nearly complete suppression of endogenous canine RHO RNA, while the human RHO replacement cDNA resulted in up to 30% of normal RHO protein levels. Noninvasive retinal imaging showed photoreceptors in treated areas were completely protected from retinal degeneration. Histopathology confirmed retention of normal photoreceptor structure and RHO expression in rod outer segments. Long-term (>8 mo) follow-up by retinal imaging and electroretinography indicated stable structural and functional preservation. The efficacy of this gene therapy in a clinically relevant large-animal model paves the way for treating patients with RHO-adRP.
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16
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LaVail MM, Nishikawa S, Steinberg RH, Naash MI, Duncan JL, Trautmann N, Matthes MT, Yasumura D, Lau-Villacorta C, Chen J, Peterson WM, Yang H, Flannery JG. Phenotypic characterization of P23H and S334ter rhodopsin transgenic rat models of inherited retinal degeneration. Exp Eye Res 2018; 167:56-90. [PMID: 29122605 PMCID: PMC5811379 DOI: 10.1016/j.exer.2017.10.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/25/2017] [Accepted: 10/31/2017] [Indexed: 02/07/2023]
Abstract
We produced 8 lines of transgenic (Tg) rats expressing one of two different rhodopsin mutations in albino Sprague-Dawley (SD) rats. Three lines were generated with a proline to histidine substitution at codon 23 (P23H), the most common autosomal dominant form of retinitis pigmentosa in the United States. Five lines were generated with a termination codon at position 334 (S334ter), resulting in a C-terminal truncated opsin protein lacking the last 15 amino acid residues and containing all of the phosphorylation sites involved in rhodopsin deactivation, as well as the terminal QVAPA residues important for rhodopsin deactivation and trafficking. The rates of photoreceptor (PR) degeneration in these models vary in proportion to the ratio of mutant to wild-type rhodopsin. The models have been widely studied, but many aspects of their phenotypes have not been described. Here we present a comprehensive study of the 8 Tg lines, including the time course of PR degeneration from the onset to one year of age, retinal structure by light and electron microscopy (EM), hemispheric asymmetry and gradients of rod and cone degeneration, rhodopsin content, gene dosage effect, rapid activation and invasion of the outer retina by presumptive microglia, rod outer segment disc shedding and phagocytosis by the retinal pigmented epithelium (RPE), and retinal function by the electroretinogram (ERG). The biphasic nature of PR cell death was noted, as was the lack of an injury-induced protective response in the rat models. EM analysis revealed the accumulation of submicron vesicular structures in the interphotoreceptor space during the peak period of PR outer segment degeneration in the S334ter lines. This is likely due to the elimination of the trafficking consensus domain as seen before as with other rhodopsin mutants lacking the C-terminal QVAPA. The 8 rhodopsin Tg lines have been, and will continue to be, extremely useful models for the experimental study of inherited retinal degenerations.
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Affiliation(s)
- Matthew M LaVail
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Shimpei Nishikawa
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Roy H Steinberg
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd., Room 2011, Houston, TX 77204-5060, USA.
| | - Jacque L Duncan
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Nikolaus Trautmann
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Michael T Matthes
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Douglas Yasumura
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Cathy Lau-Villacorta
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Jeannie Chen
- Zilka Neurogenetic Institute, USC Keck School of Medicine, Los Angeles, CA 90089-2821, USA.
| | - Ward M Peterson
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Haidong Yang
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - John G Flannery
- School of Optometry, UC Berkeley, Berkeley, CA 94720-2020, USA.
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Froebel BR, Trujillo AJ, Sullivan JM. Effects of Pathogenic Variations in the Human Rhodopsin Gene (hRHO) on the Predicted Accessibility for a Lead Candidate Ribozyme. Invest Ophthalmol Vis Sci 2017; 58:3576-3591. [PMID: 28715844 PMCID: PMC5516567 DOI: 10.1167/iovs.16-20877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Purpose The mutation-independent strategy for hammerhead ribozyme (hhRz) or RNA interference (RNAi)-based gene therapeutics to treat autosomal dominant diseases is predicated on the hypothesis that a single therapeutic would equivalently suppress all/most of the diverse mutant mRNAs in patients with the disease phenotype. However, the hypothesis has not been formally tested. We address this through a comprehensive bioinformatics study of how mutations affect target mRNA structure accessibility for a single lead hhRz therapeutic (725GUC↓), designed against human rod rhodopsin mRNA (hRHO), for patients with hRHO mutations that cause autosomal dominant retinitis pigmentosa. Methods A total of 199 in silico coding region mutations (missense, nonsense, insert, deletion, indel) were made in hRHO mRNA based on Human Gene Mutation Database and Database of Single Nucleotide Polymorphisms. Each mRNA was folded with MFold, SFold, and OligoWalk algorithms and subjected to a bioinformatics model called multiparameter prediction of RNA accessibility. Predicted accessibility of each mutant over both a broad local region and the explicit lead ribozyme annealing site were compared quantitatively to wild-type hRHO mRNA. Results Accessibility of the 725GUC↓ site is sensitive to some mutations. For single nucleotide missense mutations, proximity of the mutation to the hhRz annealing site increases the impact on predicted accessibility, but some distant mutations also influence accessibility. Conclusions A mutation-independent strategy appears viable in this specific context but certain mutations could significantly influence ribozyme or RNAi efficacy through impact on accessibility at the target annealing site/region. This possibility must be considered in applications of this gene therapy strategy.
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Affiliation(s)
- Beau R Froebel
- Research Service, VA Western New York Healthcare System, Buffalo, New York, United States 2Department of Ophthalmology, State University of New York, University at Buffalo, Buffalo, New York, United States 3The Ross Eye Institute of University at Buffalo, Buffalo, New York, United States
| | - Alexandria J Trujillo
- Research Service, VA Western New York Healthcare System, Buffalo, New York, United States 2Department of Ophthalmology, State University of New York, University at Buffalo, Buffalo, New York, United States 4Department of Pharmacology/Toxicology, State University of New York, University at Buffalo, Buffalo, New York, United States
| | - Jack M Sullivan
- Research Service, VA Western New York Healthcare System, Buffalo, New York, United States 2Department of Ophthalmology, State University of New York, University at Buffalo, Buffalo, New York, United States 3The Ross Eye Institute of University at Buffalo, Buffalo, New York, United States 4Department of Pharmacology/Toxicology, State University of New York, University at Buffalo, Buffalo, New York, United States 5Department of Physiology/Biophysics, State University of New York, University at Buffalo, Buffalo, New York, United States 6Neuroscience Program, State University of New York, University at Buffalo, Buffalo, New York, United States 7The RNA Institute, University at Albany-State University of New York, Albany, New York, United States
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18
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Yau EH, Butler MC, Sullivan JM. A cellular high-throughput screening approach for therapeutic trans-cleaving ribozymes and RNAi against arbitrary mRNA disease targets. Exp Eye Res 2016; 151:236-55. [PMID: 27233447 DOI: 10.1016/j.exer.2016.05.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 04/25/2016] [Accepted: 05/22/2016] [Indexed: 12/11/2022]
Abstract
Major bottlenecks in development of therapeutic post transcriptional gene silencing (PTGS) agents (e.g. ribozymes, RNA interference, antisense) include the challenge of mapping rare accessible regions of the mRNA target that are open for annealing and cleavage, testing and optimization of agents in human cells to identify lead agents, testing for cellular toxicity, and preclinical evaluation in appropriate animal models of disease. Methods for rapid and reliable cellular testing of PTGS agents are needed to identify potent lead candidates for optimization. Our goal was to develop a means of rapid assessment of many RNA agents to identify a lead candidate for a given mRNA associated with a disease state. We developed a rapid human cell-based screening platform to test efficacy of hammerhead ribozyme (hhRz) or RNA interference (RNAi) constructs, using a model retinal degeneration target, human rod opsin (RHO) mRNA. The focus is on RNA Drug Discovery for diverse retinal degeneration targets. To validate the approach, candidate hhRzs were tested against NUH↓ cleavage sites (N = G,C,A,U; H = C,A,U) within the target mRNA of secreted alkaline phosphatase (SEAP), a model gene expression reporter, based upon in silico predictions of mRNA accessibility. HhRzs were embedded in a larger stable adenoviral VAI RNA scaffold for high cellular expression, cytoplasmic trafficking, and stability. Most hhRz expression plasmids exerted statistically significant knockdown of extracellular SEAP enzyme activity when readily assayed by a fluorescence enzyme assay intended for high throughput screening (HTS). Kinetics of PTGS knockdown of cellular targets is measureable in live cells with the SEAP reporter. The validated SEAP HTS platform was transposed to identify lead PTGS agents against a model hereditary retinal degeneration target, RHO mRNA. Two approaches were used to physically fuse the model retinal gene target mRNA to the SEAP reporter mRNA. The most expedient way to evaluate a large set of potential VAI-hhRz expression plasmids against diverse NUH↓ cleavage sites uses cultured human HEK293S cells stably expressing a dicistronic Target-IRES-SEAP target fusion mRNA. Broad utility of this rational RNA drug discovery approach is feasible for any ophthalmological disease-relevant mRNA targets and any disease mRNA targets in general. The approach will permit rank ordering of PTGS agents based on potency to identify a lead therapeutic compound for further optimization.
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Affiliation(s)
- Edwin H Yau
- Department of Pharmacology/Toxicology, University at Buffalo- SUNY, Buffalo, NY 14209, USA; Department of Ophthalmology (Ira G. Ross Eye Institute), University at Buffalo- SUNY, Buffalo, NY 14209, USA
| | - Mark C Butler
- Department of Ophthalmology (Ira G. Ross Eye Institute), University at Buffalo- SUNY, Buffalo, NY 14209, USA
| | - Jack M Sullivan
- Research Service, VA Western New York Healthcare System, Buffalo, NY 14215, USA; Department of Ophthalmology (Ira G. Ross Eye Institute), University at Buffalo- SUNY, Buffalo, NY 14209, USA; Department of Pharmacology/Toxicology, University at Buffalo- SUNY, Buffalo, NY 14209, USA; Department of Physiology/Biophysics, University at Buffalo- SUNY, Buffalo, NY 14209, USA; Neuroscience Program, University at Buffalo- SUNY, Buffalo, NY 14209, USA; SUNY Eye Institute, University at Albany- SUNY, USA; RNA Institute, University at Albany- SUNY, USA.
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19
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Butler MC, Sullivan JM. A Novel, Real-Time, In Vivo Mouse Retinal Imaging System. Invest Ophthalmol Vis Sci 2016; 56:7159-68. [PMID: 26551329 DOI: 10.1167/iovs.14-16370] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE To develop an efficient, low-cost instrument for robust real-time imaging of the mouse retina in vivo, and assess system capabilities by evaluating various animal models. METHODS Following multiple disappointing attempts to visualize the mouse retina during a subretinal injection using commercially available systems, we identified the key limitation to be inadequate illumination due to off axis illumination and poor optical train optimization. Therefore, we designed a paraxial illumination system for Greenough-type stereo dissecting microscope incorporating an optimized optical launch and an efficiently coupled fiber optic delivery system. Excitation and emission filters control spectral bandwidth. A color coupled-charged device (CCD) camera is coupled to the microscope for image capture. Although, field of view (FOV) is constrained by the small pupil aperture, the high optical power of the mouse eye, and the long working distance (needed for surgical manipulations), these limitations can be compensated by eye positioning in order to observe the entire retina. RESULTS The retinal imaging system delivers an adjustable narrow beam to the dilated pupil with minimal vignetting. The optic nerve, vasculature, and posterior pole are crisply visualized and the entire retina can be observed through eye positioning. Normal and degenerative retinal phenotypes can be followed over time. Subretinal or intraocular injection procedures are followed in real time. Real-time, intravenous fluorescein angiography for the live mouse has been achieved. CONCLUSIONS A novel device is established for real-time viewing and image capture of the small animal retina during subretinal injections for preclinical gene therapy studies.
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Affiliation(s)
- Mark C Butler
- Research Service, VA Western New York Healthcare System, Buffalo, New York, United States 2Department of Ophthalmology, Ross Eye Institute, University at Buffalo-SUNY, Buffalo, New York, United States
| | - Jack M Sullivan
- Research Service, VA Western New York Healthcare System, Buffalo, New York, United States 2Department of Ophthalmology, Ross Eye Institute, University at Buffalo-SUNY, Buffalo, New York, United States 3Department of Pharmacology/Toxicology, University at
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20
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Trapani I, Banfi S, Simonelli F, Surace EM, Auricchio A. Gene therapy of inherited retinal degenerations: prospects and challenges. Hum Gene Ther 2016; 26:193-200. [PMID: 25762209 DOI: 10.1089/hum.2015.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Because of its favorable anatomical and immunological characteristics, the eye has been at the forefront of translational gene therapy. Dozens of promising proofs of concept have been obtained in animal models of inherited retinal degenerations (IRDs), and some of them have been relayed to the clinic. The results from the first clinical trials for a congenital form of blindness have generated great interest and have demonstrated the safety and efficacy of intraocular administrations of viral vectors in humans. However, this progress has also generated new questions and posed challenges that need to be addressed to further expand the applicability of gene therapy in the eye, including safe delivery of viral vectors to the outer retina, treatment of dominant IRDs as well as of IRDs caused by mutations in large genes, and, finally, selection of the appropriate IRDs and patients to maximize the efficacy of gene transfer. This review summarizes the strategies that are currently being exploited to overcome these challenges and drive the clinical development of retinal gene therapy.
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Affiliation(s)
- Ivana Trapani
- 1 Telethon Institute of Genetics and Medicine (TIGEM) , Pozzuoli, Naples 80078, Italy
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21
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Murray SF, Jazayeri A, Matthes MT, Yasumura D, Yang H, Peralta R, Watt A, Freier S, Hung G, Adamson PS, Guo S, Monia BP, LaVail MM, McCaleb ML. Allele-Specific Inhibition of Rhodopsin With an Antisense Oligonucleotide Slows Photoreceptor Cell Degeneration. Invest Ophthalmol Vis Sci 2016; 56:6362-75. [PMID: 26436889 DOI: 10.1167/iovs.15-16400] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PURPOSE To preserve photoreceptor cell structure and function in a rodent model of retinitis pigmentosa with P23H rhodopsin by selective inhibition of the mutant rhodopsin allele using a second generation antisense oligonucleotide (ASO). METHODS Wild-type mice and rats were treated with ASO by intravitreal (IVT) injection and rhodopsin mRNA and protein expression were measured. Transgenic rats expressing the murine P23H rhodopsin gene (P23H transgenic rat Line 1) were administered either a mouse-specific P23H ASO or a control ASO. The contralateral eye was injected with PBS and used as a comparator control. Electroretinography (ERG) measurements and analyses of the retinal outer nuclear layer were conducted and correlated with rhodopsin mRNA levels. RESULTS Rhodopsin mRNA and protein expression was reduced after a single ASO injection in wild-type mice with a rhodopsin-specific ASO. Transgenic rat eyes that express a murine P23H rhodopsin gene injected with a murine P23H ASO had a 181 ± 39% better maximum amplitude response (scotopic a-wave) as compared with contralateral PBS-injected eyes; the response in control ASO eyes was not significantly different from comparator contralateral eyes. Morphometric analysis of the outer nuclear layer showed a significantly thicker nuclear layer in eyes injected with murine P23H ASO (18%) versus contralateral PBS-injected eyes. CONCLUSIONS Allele-specific ASO-mediated knockdown of mutant P23H rhodopsin expression slowed the rate of photoreceptor degeneration and preserved the function of photoreceptor cells in eyes of the P23H rhodopsin transgenic rat. Our data indicate that ASO treatment is a potentially effective therapy for the treatment of retinitis pigmentosa.
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Affiliation(s)
- Susan F Murray
- Isis Pharmaceuticals Carlsbad, California, United States
| | - Ali Jazayeri
- Isis Pharmaceuticals Carlsbad, California, United States
| | - Michael T Matthes
- University of California at San Francisco School of Medicine, Beckman Vision Center, San Francisco, California, United States
| | - Douglas Yasumura
- University of California at San Francisco School of Medicine, Beckman Vision Center, San Francisco, California, United States
| | - Haidong Yang
- University of California at San Francisco School of Medicine, Beckman Vision Center, San Francisco, California, United States
| | | | - Andy Watt
- Isis Pharmaceuticals Carlsbad, California, United States
| | - Sue Freier
- Isis Pharmaceuticals Carlsbad, California, United States
| | - Gene Hung
- Isis Pharmaceuticals Carlsbad, California, United States
| | | | - Shuling Guo
- Isis Pharmaceuticals Carlsbad, California, United States
| | - Brett P Monia
- Isis Pharmaceuticals Carlsbad, California, United States
| | - Matthew M LaVail
- University of California at San Francisco School of Medicine, Beckman Vision Center, San Francisco, California, United States
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Conley SM, Whalen P, Lewin AS, Naash MI. Characterization of Ribozymes Targeting a Congenital Night Blindness Mutation in Rhodopsin Mutation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:509-15. [PMID: 26427453 DOI: 10.1007/978-3-319-17121-0_68] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The G90D mutation in the rhodopsin gene leads to autosomal dominant congenital stationary night blindness (CSNB) in patients. This occurs because the G90D mutant protein cannot efficiently bind chromophore and is constitutively active. To combat this mutation, we designed and characterized two different hammerhead ribozymes to cleave G90D transcript. In vitro testing showed that the G90D1 ribozyme efficiently and specifically cleaved the mutant transcript while G90D2 cleaved both WT and mutant transcript. AAV-mediated delivery of G90D1 under the control of the mouse opsin promoter (MOP500) to G90D transgenic eyes showed that the ribozyme partially retarded the functional degeneration (as measured by electroretinography [ERG]) associated with this mutation. These results suggest that with additional optimization, ribozymes may be a useful part of the gene therapy knockdown strategy for dominant retinal disease.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd. BMSB 781, 73104, Oklahoma City, OK, USA.
| | - Patrick Whalen
- Department of Molecular Genetics and Microbiology, University of Florida, 32611, Gainesville, FL, USA
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, 32611, Gainesville, FL, USA.
| | - Muna I Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd. BMSB 781, 73104, Oklahoma City, OK, USA.
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Retinal gene delivery by adeno-associated virus (AAV) vectors: Strategies and applications. Eur J Pharm Biopharm 2015; 95:343-52. [DOI: 10.1016/j.ejpb.2015.01.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/10/2015] [Accepted: 01/12/2015] [Indexed: 11/20/2022]
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Orhan E, Dalkara D, Neuillé M, Lechauve C, Michiels C, Picaud S, Léveillard T, Sahel JA, Naash MI, Lavail MM, Zeitz C, Audo I. Genotypic and phenotypic characterization of P23H line 1 rat model. PLoS One 2015; 10:e0127319. [PMID: 26009893 PMCID: PMC4444340 DOI: 10.1371/journal.pone.0127319] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/13/2015] [Indexed: 01/26/2023] Open
Abstract
Rod-cone dystrophy, also known as retinitis pigmentosa (RP), is the most common inherited degenerative photoreceptor disease, for which no therapy is currently available. The P23H rat is one of the most commonly used autosomal dominant RP models. It has been created by incorporation of a mutated mouse rhodopsin (Rho) transgene in the wild-type (WT) Sprague Dawley rat. Detailed genetic characterization of this transgenic animal has however never been fully reported. Here we filled this knowledge gap on P23H Line 1 rat (P23H-1) and provide additional phenotypic information applying non-invasive and state-of-the-art in vivo techniques that are relevant for preclinical therapeutic evaluations. Transgene sequence was analyzed by Sanger sequencing. Using quantitative PCR, transgene copy number was calculated and its expression measured in retinal tissue. Full field electroretinography (ERG) and spectral domain optical coherence tomography (SD-OCT) were performed at 1-, 2-, 3- and 6-months of age. Sanger sequencing revealed that P23H-1 rat carries the mutated mouse genomic Rho sequence from the promoter to the 3’ UTR. Transgene copy numbers were estimated at 9 and 18 copies in the hemizygous and homozygous rats respectively. In 1-month-old hemizygous P23H-1 rats, transgene expression represented 43% of all Rho expressed alleles. ERG showed a progressive rod-cone dysfunction peaking at 6 months-of-age. SD-OCT confirmed a progressive thinning of the photoreceptor cell layer leading to the disappearance of the outer retina by 6 months with additional morphological changes in the inner retinal cell layers in hemizygous P23H-1 rats. These results provide precise genotypic information of the P23H-1 rat with additional phenotypic characterization that will serve basis for therapeutic interventions, especially for those aiming at gene editing.
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Affiliation(s)
- Elise Orhan
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - Deniz Dalkara
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - Marion Neuillé
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - Christophe Lechauve
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - Christelle Michiels
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - Serge Picaud
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - Thierry Léveillard
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - José-Alain Sahel
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, DHU ViewMaintain, INSERM-DHOS CIC 1423, Paris, France
- Institute of Ophthalmology, University College of London, London, United Kingdom
- Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
- Academie des Sciences, Institut de France, Paris, France
| | - Muna I. Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Matthew M. Lavail
- Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America
- Department of Anatomy, University of California San Francisco, San Francisco, California United States of America
| | - Christina Zeitz
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
| | - Isabelle Audo
- INSERM, U968, Paris, France
- CNRS, UMR_7210, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, DHU ViewMaintain, INSERM-DHOS CIC 1423, Paris, France
- Institute of Ophthalmology, University College of London, London, United Kingdom
- * E-mail:
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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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26
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Cuenca N, Fernández-Sánchez L, Campello L, Maneu V, De la Villa P, Lax P, Pinilla I. Cellular responses following retinal injuries and therapeutic approaches for neurodegenerative diseases. Prog Retin Eye Res 2014; 43:17-75. [PMID: 25038518 DOI: 10.1016/j.preteyeres.2014.07.001] [Citation(s) in RCA: 296] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 01/17/2023]
Abstract
Retinal neurodegenerative diseases like age-related macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa each have a different etiology and pathogenesis. However, at the cellular and molecular level, the response to retinal injury is similar in all of them, and results in morphological and functional impairment of retinal cells. This retinal degeneration may be triggered by gene defects, increased intraocular pressure, high levels of blood glucose, other types of stress or aging, but they all frequently induce a set of cell signals that lead to well-established and similar morphological and functional changes, including controlled cell death and retinal remodeling. Interestingly, an inflammatory response, oxidative stress and activation of apoptotic pathways are common features in all these diseases. Furthermore, it is important to note the relevant role of glial cells, including astrocytes, Müller cells and microglia, because their response to injury is decisive for maintaining the health of the retina or its degeneration. Several therapeutic approaches have been developed to preserve retinal function or restore eyesight in pathological conditions. In this context, neuroprotective compounds, gene therapy, cell transplantation or artificial devices should be applied at the appropriate stage of retinal degeneration to obtain successful results. This review provides an overview of the common and distinctive features of retinal neurodegenerative diseases, including the molecular, anatomical and functional changes caused by the cellular response to damage, in order to establish appropriate treatments for these pathologies.
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Affiliation(s)
- Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain; Multidisciplinary Institute for Environmental Studies "Ramon Margalef", University of Alicante, Alicante, Spain.
| | - Laura Fernández-Sánchez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Pedro De la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Aragon Institute of Health Sciences, Zaragoza, Spain
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Abstract
Significant advances have been made over the last decade or two in the elucidation of the molecular pathogenesis of inherited ocular disorders. In particular, remarkable successes have been achieved in exploration of gene-based medicines for these conditions, both in preclinical and in clinical studies. Progress in the development of gene therapies targeted toward correcting the primary genetic defect or focused on modulating secondary effects associated with retinal pathologies are discussed in the review. Likewise, the recent utilization of genes encoding light-sensing molecules to provide new functions to residual retinal cells in the degenerating retina is discussed. While a great deal has been learned over the last two decades, the next decade should result in an increasing number of preclinical studies progressing to human clinical trial, an exciting prospect for patients, those active in research and development and bystanders alike.
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Braun-Falco M, Rödl D. Recombinant adeno-associated virus vectors for somatic gene therapy in dermatology. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/17469872.2.2.167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Petrs-Silva H, Linden R. Advances in gene therapy technologies to treat retinitis pigmentosa. Clin Ophthalmol 2013; 8:127-36. [PMID: 24391438 PMCID: PMC3878960 DOI: 10.2147/opth.s38041] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Retinitis pigmentosa (RP) is a class of diseases that leads to progressive degeneration of the retina. Experimental approaches to gene therapy for the treatment of inherited retinal dystrophies have advanced in recent years, inclusive of the safe delivery of genes to the human retina. This review is focused on the development of gene therapy for RP using recombinant adenoassociated viral vectors, which show a positive safety record and have so far been successful in several clinical trials for congenital retinal disease. Gene therapy for RP is under development in a variety of animal models, and the results raise expectations of future clinical application. Nonetheless, the translation of such strategies to the bedside requires further understanding of the mutations and mechanisms that cause visual defects, as well as thorough examination of potential adverse effects.
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Affiliation(s)
- Hilda Petrs-Silva
- Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rafael Linden
- Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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30
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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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31
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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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32
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Lipinski DM, Thake M, MacLaren RE. Clinical applications of retinal gene therapy. Prog Retin Eye Res 2013; 32:22-47. [DOI: 10.1016/j.preteyeres.2012.09.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 09/04/2012] [Accepted: 09/04/2012] [Indexed: 02/08/2023]
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Rossmiller B, Mao H, Lewin AS. Gene therapy in animal models of autosomal dominant retinitis pigmentosa. Mol Vis 2012; 18:2479-96. [PMID: 23077406 PMCID: PMC3472929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 10/04/2012] [Indexed: 12/04/2022] Open
Abstract
Gene therapy for dominantly inherited genetic disease is more difficult than gene-based therapy for recessive disorders, which can be treated with gene supplementation. Treatment of dominant disease may require gene supplementation partnered with suppression of the expression of the mutant gene either at the DNA level, by gene repair, or at the RNA level by RNA interference or transcriptional repression. In this review, we examine some of the gene delivery approaches used to treat animal models of autosomal dominant retinitis pigmentosa, focusing on those models associated with mutations in the gene for rhodopsin. We conclude that combinatorial approaches have the greatest promise for success.
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McGill TJ, Prusky GT, Douglas RM, Yasumura D, Matthes MT, Lowe RJ, Duncan JL, Yang H, Ahern K, Daniello KM, Silver B, LaVail MM. Discordant anatomical, electrophysiological, and visual behavioral profiles of retinal degeneration in rat models of retinal degenerative disease. Invest Ophthalmol Vis Sci 2012; 53:6232-44. [PMID: 22899760 DOI: 10.1167/iovs.12-9569] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
PURPOSE To assess structural, functional, and visual behavioral relationships in mutant rhodopsin transgenic (Tg) rats and to determine whether early optokinetic tracking (OKT) visual experience, known to permanently elevate visual thresholds in normal rats, can enhance vision in rats with photoreceptor degeneration. METHODS Eight lines of pigmented Tg rats and RCS rats were used in this study. OKT thresholds were tested at single ages (1, 2, 3, 4, and 6 months) in naïve groups of rats, or daily in groups that began at eye-opening (P15) or 10 days later (P25). Electroretinogram (ERG) response amplitudes were recorded after OKT testing, and outer nuclear layer (ONL) thickness measurements were then obtained. RESULTS OKT thresholds, when measured at a single time point in naïve Tg lines beginning at P30, did not decline until months after significant photoreceptor loss. Daily testing of Tg lines resulted mostly with OKT thresholds inversely related to photoreceptor degeneration, with rapid degenerations resulting in sustained OKT thresholds for long periods despite the rapid photoreceptor loss. Slower degenerations resulted in rapid decline of thresholds, long before the loss of most photoreceptors, which was even more pronounced when daily testing began at eye opening. This amplified loss of function was not a result of testing-induced damage to the rod or cone photoreceptors, as ERG amplitudes and ONL thicknesses were the same as untested controls. CONCLUSIONS The unexpected lack of correlation of OKT testing with photoreceptor degeneration in the Tg rats emphasizes the need in behavioral therapeutic studies for careful analysis of visual thresholds of experimental animals prior to therapeutic intervention.
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Affiliation(s)
- Trevor J McGill
- Department of Ophthalmology, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, USA.
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35
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Greenwald DL, Cashman SM, Kumar-Singh R. Mutation-independent rescue of a novel mouse model of Retinitis Pigmentosa. Gene Ther 2012; 20:425-34. [PMID: 22809998 DOI: 10.1038/gt.2012.53] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Retinitis Pigmentosa (RP) is the leading cause of inherited blindness in the developed world, affecting approximately 1 in 3000 individuals. Although there is currently no cure for RP, the genetic pathology has been well established. In this study, we developed a novel mouse model of RP (huRhoP347S) expressing a pathogenic human rhodopsin gene with a Pro347Ser (P347S) mutation on a rhodopsin knockout background. These mice undergo severe retinal degeneration at 1 month of age. In contrast to prior studies, this model was administered a gene therapy treatment at 19 days postnata. We evaluated several self-complementary adeno-associated virus (AAV) serotypes for photoreceptor tropism, including scAAV2/2, scAAV2/5, scAAV2/6.2 and scAAV2/9, and found that scAAV2/9 transduced photoreceptors with greater efficiency and expression than other vectors. We engineered an scAAV2/9 vector to contain a microRNA sequence specifically targeting the human rhodopsin gene and demonstrated its ability to silence rhodopsin by 60.2±8.2% in vitro. In addition, we constructed an scAAV2/9 vector to contain a replacement 'codon-modified' rhodopsin transgene (RhoR2) that was resistant to degradation by the microRNA. We found that delivery of the RhoR2 by scAAV2/9 is capable of restoring vision to rhodopsin knockout mice, and rescuing our novel transgenic huRhoP347S mouse model of dominant RP. Average a-wave responses of RhoR2-injected eyes were 1.8-fold higher than those of control-injected eyes. We found that delivery of the microRNA and replacement rhodopsin in a 1:2 ratio produced an average electroretinography (ERG) a-wave response of 17.4±2.9 compared to 6.5±2.8 μV for eyes injected with negative control virus.
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Affiliation(s)
- D L Greenwald
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111, USA
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36
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Kunte MM, Choudhury S, Manheim JF, Shinde VM, Miura M, Chiodo VA, Hauswirth WW, Gorbatyuk OS, Gorbatyuk MS. ER stress is involved in T17M rhodopsin-induced retinal degeneration. Invest Ophthalmol Vis Sci 2012; 53:3792-800. [PMID: 22589437 DOI: 10.1167/iovs.11-9235] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The human rhodopsin (Rho) mutation T17M leads to autosomal dominant retinitis pigmentosa (adRP). The goal of our study was to elucidate the role of endoplasmic reticulum (ER) stress in retinal degeneration in hT17M Rho mice and identify potential candidates for adRP gene therapy. METHODS We used transgenic mice expressing the ER stress-activated indicator (ERAI) and hT17M Rho to evaluate the activation of ER stress responses. Quantitative reverse transcription PCR (qRT-PCR) was used to analyze changes in the expression of 30 unfolded protein response (UPR)-associated genes at P12, 15, 18, 21, and 25. The cytosolic fraction of hT17M Rho retinal cells was used to measure the release of cytochrome C and apoptotic inducing factor-1 (AIF1) by Western blotting. Optical coherence tomography (OCT) analysis was performed for 1-month-old hT17M Rho mice. RESULTS hT17M Rho was localized in the outer nuclear layer (ONL) of T17M(+/-)ERAI(+/-) photoreceptors as well as C57BL/6 retinas injected with AAV-hT17M Rho-GFP. In P15 hT17M Rho retinas, we observed an up-regulation of UPR genes (Atf4, Eif2α, Xbp1, Bip, Canx, and Hsp90), autophagy genes and proapoptotic Bcl2 genes. OCT, and the downregulation of Nrl and Crx gene expression confirmed that cell death occurs in 55% of photoreceptors via the up-regulation of caspase-3 and caspase-12, and the release of AIF1 from the mitochondria. CONCLUSIONS The ER stress response is involved in retinal degeneration in hT17M Rho mice. The final demise of photoreceptors occurs via apoptosis involving ER stress-associated and mitochondria-induced caspase activation. We identified Atg5, Atg7, Bax, Bid, Bik, and Noxa as potential therapeutic targets for adRP treatment.
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Affiliation(s)
- Mansi M Kunte
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
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37
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Mao H, Gorbatyuk MS, Rossmiller B, Hauswirth WW, Lewin AS. Long-term rescue of retinal structure and function by rhodopsin RNA replacement with a single adeno-associated viral vector in P23H RHO transgenic mice. Hum Gene Ther 2012; 23:356-66. [PMID: 22289036 DOI: 10.1089/hum.2011.213] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Many mutations in the human rhodopsin gene (RHO) cause autosomal dominant retinitis pigmentosa (ADRP). Our previous studies with a P23H (proline-23 substituted by histidine) RHO transgenic mouse model of ADRP demonstrated significant improvement of retinal function and preservation of retinal structure after transfer of wild-type rhodopsin by AAV. In this study we demonstrate long-term rescue of retinal structure and function by a single virus expressing both RHO replacement cDNA and small interfering RNA (siRNA) to digest mouse Rho and human P23H RHO mRNA. This combination should prevent overexpression of rhodopsin, which can be deleterious to photoreceptors. On the basis of the electroretinogram (ERG) response, degeneration of retinal function was arrested at 2 months postinjection, and the response was maintained at this level until termination at 9 months. Preservation of the ERG response in P23H RHO mice reflected survival of photoreceptors: both the outer nuclear layer (ONL) and outer segments of photoreceptor cells maintained the same thickness as in nontransgenic mice, whereas the control injected P23H eyes exhibited severe thinning of the ONL and outer segments. These findings suggest that delivery of both a modified cDNA and an siRNA by a single adeno-associated viral vector provided long-term rescue of ADRP in this model. Because the siRNA targets human as well as mouse rhodopsin mRNAs, the combination vector may be useful for the treatment of human disease.
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Affiliation(s)
- Haoyu Mao
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
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38
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Abstract
Through the combined study of model organisms, cell biology, cell signaling and medical genetics we have significantly increased our understanding of the structure and functions of the vertebrate cilium. This ancient organelle has now emerged as a crucial component of certain signaling and sensory perception pathways in both developmental and homeostatic contexts. Here, we provide a snapshot of the structure, function and distribution of the vertebrate cilium and of the pathologies that are associated with its dysfunction.
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Affiliation(s)
- Edwin C Oh
- Center for Human Disease Modeling, Department of Cell Biology, Duke University, Durham NC 27710, USA.
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39
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Abstract
Twelve AAV serotypes have been described so far in human and nonhuman primate (NHP) populations while surprisingly high diversity of AAV sequences is detected in tissue biopsies. The analysis of these novel AAV sequences has indicated a rapid evolution of the viral genome both by accumulation of mutations and recombination. This chapter describes how this rich resource of naturally evolved sequences is used to derive gene transfer vectors with a wide array of activities depending on the nature of the cap gene used in the packaging system. AAV2-based recombinant genomes have been packaged in dozens of different capsid types, resulting in a wide array of "pseudotyped vectors" that constitute a rich resource for the development of gene therapy clinical trials. We describe a polymerase chain reaction-based molecular rescue method for novel AAV isolation that uses primers designed to recognize the highly conserved regions in known AAV isolates and generate amplicons across the hypervariable regions of novel AAV genomes present in the analyzed sample.
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40
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Hollingsworth TJ, Gross AK. Defective trafficking of rhodopsin and its role in retinal degenerations. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 293:1-44. [PMID: 22251557 DOI: 10.1016/b978-0-12-394304-0.00006-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Retinitis pigmentosa is a retinal degeneration transmitted by varied modes of inheritance and affects approximately 1 in 4000 individuals. The photoreceptors of the outer retina, as well as the retinal pigmented epithelium which supports the outer retina metabolically and structurally, are the retinal regions most affected by the disorder. In several forms of retinitis pigmentosa, the mislocalization of the rod photoreceptor protein rhodopsin is thought to be a contributing factor underlying the pathophysiology seen in patients. The mutations causing this mislocalization often occur in genes coding proteins involved in ciliary formation, vesicular transport, rod outer segment disc formation, and stability, as well as the rhodopsin protein itself. Often, these mutations result in the most early-onset cases of both recessive and dominant retinitis pigmentosa, and the following presents a discussion of the proteins, their degenerative phenotypes, and possible treatments of the disease.
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Affiliation(s)
- T J Hollingsworth
- Department of Vision Sciences, University of Alabama, Birmingham, Alabama, USA
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Abstract
Retinal gene therapy holds great promise for the treatment of inherited and noninherited blinding diseases such as retinitis pigmentosa and age-related macular degeneration. The most widely used vectors for ocular gene delivery are based on adeno-associated virus (AAV) because it mediates long-term transgene expression in a variety of retinal cell types and elicits minimal immune responses. Inherited retinal diseases are nonlethal and have a wide level of genetic heterogeneity. Many of the genes have now been identified and their function elucidated, providing a major step towards the development of gene-based treatments. Extensive preclinical evaluation of gene transfer strategies in small and large animal models is key to the development of successful gene-based therapies for the retina. These preclinical studies have already allowed the field to reach the point where gene therapy to treat inherited blindness has been brought to clinical trial.In this chapter, we focus on AAV-mediated specific gene therapy for inherited retinal degenerative diseases, describing the disease targets, the preclinical studies in animal models and the recent success of the LCA-RPE65 clinical trials.
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Gene delivery of wild-type rhodopsin rescues retinal function in an autosomal dominant retinitis pigmentosa mouse model. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:199-205. [PMID: 22183334 DOI: 10.1007/978-1-4614-0631-0_27] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Autosomal dominant retinitis pigmentosa (ADRP) is frequently caused by mutations within the gene for the opsin of rod photoreceptor cells. Studies on transgenic mice, carrying mutated rhodopsin (RHO) transgene on different genetic backgrounds suggested that that an increased amount of wild-type RHO in ADRP photoreceptors attenuated the impact of the mutant transgene. Therefore, we employed a gene therapy approach with a help of Adeno-associated virus (AAV) to treat mice expressing a P23H mutant human RHO transgene. Knowing that AAV5 primarily transduces photoreceptor cells, we designed “hardened” form of the rhodopsin gene (RHO301) that expressed normal rhodopsin and was specifically resistant to degradation by the previously tested siRNA301. AAV5 RHO301 was subretinaly injected into the right eyes of P23H RHO mice at post-natal day 15. Animals were analyzed monthly by electroretinography (ERG) for 6 months. Analysis of the full field scotopic electroretinogram (ERG) demonstrated that increased expression of opsin slowed the rate of retinal degeneration in P23H mice with increased amplitudes in both a-wave and b-wave amplitudes compared to control eyes. An increase in the ERG amplitudes was correlated with improvement of retinal structure. The thickness of the outer nuclear layer in AAV-RHO301 injected eyes was increased by 80% compared to control eyes. This finding indicates that wild -type RHO could rescue the retinal degeneration in transgenic mice carrying a dominant RHO mutation and that increased production of normal rhodopsin could suppress the effect of the mutant protein. These findings suggest that wild-type RHO can used as a therapeutic agent to retard retinal degeneration in ADRP caused by different mutations of RHO via increased production of normal rhodopsin protein.
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Farrar GJ, Millington-Ward S, Chadderton N, Humphries P, Kenna PF. Gene-based therapies for dominantly inherited retinopathies. Gene Ther 2011; 19:137-44. [DOI: 10.1038/gt.2011.172] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Sullivan JM, Yau EH, Kolniak TA, Sheflin LG, Taggart RT, Abdelmaksoud HE. Variables and strategies in development of therapeutic post-transcriptional gene silencing agents. J Ophthalmol 2011; 2011:531380. [PMID: 21785698 PMCID: PMC3138052 DOI: 10.1155/2011/531380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 02/17/2011] [Accepted: 02/28/2011] [Indexed: 11/24/2022] Open
Abstract
Post-transcriptional gene silencing (PTGS) agents such as ribozymes, RNAi and antisense have substantial potential for gene therapy of human retinal degenerations. These technologies are used to knockdown a specific target RNA and its cognate protein. The disease target mRNA may be a mutant mRNA causing an autosomal dominant retinal degeneration or a normal mRNA that is overexpressed in certain diseases. All PTGS technologies depend upon the initial critical annealing event of the PTGS ligand to the target RNA. This event requires that the PTGS agent is in a conformational state able to support hybridization and that the target have a large and accessible single-stranded platform to allow rapid annealing, although such platforms are rare. We address the biocomplexity that currently limits PTGS therapeutic development with particular emphasis on biophysical variables that influence cellular performance. We address the different strategies that can be used for development of PTGS agents intended for therapeutic translation. These issues apply generally to the development of PTGS agents for retinal, ocular, or systemic diseases. This review should assist the interested reader to rapidly appreciate critical variables in PTGS development and facilitate initial design and testing of such agents against new targets of clinical interest.
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Affiliation(s)
- Jack M. Sullivan
- Department of Ophthalmology, University at Buffalo SUNY, Buffalo, NY 14214, USA
- Department of Pharmacology and Toxicology, University at Buffalo SUNY, Buffalo, NY 14214, USA
- Department of Physiology and Biophysics, University at Buffalo SUNY, Buffalo, NY 14214, USA
- Neuroscience Program, University at Buffalo SUNY, Buffalo, NY 14214, USA
- Ross Eye Institute, University at Buffalo SUNY, Buffalo, NY 14209, USA
- Veterans Administration Western New York Healthcare System, Medical Research, Buffalo, NY 14215, USA
| | - Edwin H. Yau
- Department of Ophthalmology, University at Buffalo SUNY, Buffalo, NY 14214, USA
- Department of Pharmacology and Toxicology, University at Buffalo SUNY, Buffalo, NY 14214, USA
| | - Tiffany A. Kolniak
- Department of Ophthalmology, University at Buffalo SUNY, Buffalo, NY 14214, USA
- Neuroscience Program, University at Buffalo SUNY, Buffalo, NY 14214, USA
| | - Lowell G. Sheflin
- Department of Ophthalmology, University at Buffalo SUNY, Buffalo, NY 14214, USA
- Veterans Administration Western New York Healthcare System, Medical Research, Buffalo, NY 14215, USA
| | - R. Thomas Taggart
- Department of Ophthalmology, University at Buffalo SUNY, Buffalo, NY 14214, USA
| | - Heba E. Abdelmaksoud
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY 13215, USA
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Vasireddy V, Chavali VRM, Joseph VT, Kadam R, Lin JH, Jamison JA, Kompella UB, Reddy GB, Ayyagari R. Rescue of photoreceptor degeneration by curcumin in transgenic rats with P23H rhodopsin mutation. PLoS One 2011; 6:e21193. [PMID: 21738619 PMCID: PMC3126808 DOI: 10.1371/journal.pone.0021193] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 05/23/2011] [Indexed: 12/27/2022] Open
Abstract
The P23H mutation in the rhodopsin gene causes rhodopsin misfolding, altered trafficking and formation of insoluble aggregates leading to photoreceptor degeneration and autosomal dominant retinitis pigmentosa (RP). There are no effective therapies to treat this condition. Compounds that enhance dissociation of protein aggregates may be of value in developing new treatments for such diseases. Anti-protein aggregating activity of curcumin has been reported earlier. In this study we present that treatment of COS-7 cells expressing mutant rhodopsin with curcumin results in dissociation of mutant protein aggregates and decreases endoplasmic reticulum stress. Furthermore we demonstrate that administration of curcumin to P23H-rhodopsin transgenic rats improves retinal morphology, physiology, gene expression and localization of rhodopsin. Our findings indicate that supplementation of curcumin improves retinal structure and function in P23H-rhodopsin transgenic rats. This data also suggest that curcumin may serve as a potential therapeutic agent in treating RP due to the P23H rhodopsin mutation and perhaps other degenerative diseases caused by protein trafficking defects.
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Affiliation(s)
- Vidyullatha Vasireddy
- Jacobs Retina Center, Department of Ophthalmology, University of California San Diego, La Jolla, California, United States of America
| | - Venkata R. M. Chavali
- Jacobs Retina Center, Department of Ophthalmology, University of California San Diego, La Jolla, California, United States of America
| | - Victory T. Joseph
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | - Rajendra Kadam
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Jonathan H. Lin
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | | | - Uday B. Kompella
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, United States of America
| | | | - Radha Ayyagari
- Jacobs Retina Center, Department of Ophthalmology, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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46
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Affiliation(s)
- Val C Sheffield
- Department of Pediatrics, Howard Hughes Medical Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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The domestic cat as a large animal model for characterization of disease and therapeutic intervention in hereditary retinal blindness. J Ophthalmol 2011; 2011:906943. [PMID: 21584261 PMCID: PMC3090773 DOI: 10.1155/2011/906943] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/04/2010] [Accepted: 01/24/2011] [Indexed: 01/09/2023] Open
Abstract
Large mammals, including canids and felids, are affected by spontaneously occurring hereditary retinal diseases with similarities to those of humans. The large mammal models may be used for thorough clinical characterization of disease processes, understanding the effects of specific mutations, elucidation of disease mechanisms, and for development of therapeutic intervention. Two well-characterized feline models are addressed in this paper. The first model is the autosomal recessive, slowly progressive, late-onset, rod-cone degenerative disease caused by a mutation in the CEP290 gene. The second model addressed in this paper is the autosomal dominant early onset rod cone dysplasia, putatively caused by the mutation found in the CRX gene. Therapeutic trials have been performed mainly in the former type including stem cell therapy, retinal transplantation, and development of ocular prosthetics. Domestic cats, having large human-like eyes with comparable spontaneous retinal diseases, are also considered useful for gene replacement therapy, thus functioning as effective model systems for further research.
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Mao H, James T, Schwein A, Shabashvili AE, Hauswirth WW, Gorbatyuk MS, Lewin AS. AAV delivery of wild-type rhodopsin preserves retinal function in a mouse model of autosomal dominant retinitis pigmentosa. Hum Gene Ther 2011; 22:567-75. [PMID: 21126223 DOI: 10.1089/hum.2010.140] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Autosomal dominant retinitis pigmentosa (ADRP) is frequently caused by mutations in RHO, the gene for rod photoreceptor opsin. Earlier, a study on mice carrying mutated rhodopsin transgenes on either RHO + / + or RHO + /- backgrounds suggested that the amount of wild-type rhodopsin affected survival of photoreceptors. Therefore, we treated P23H RHO transgenic mice with adeno-associated virus serotype 5 (AAV5) expressing a cDNA clone of the rhodopsin gene (RHO301) that expressed normal opsin from the mouse opsin promoter. Analysis of the electroretinogram (ERG) demonstrated that increased expression of RHO301 slowed the rate of retinal degeneration in P23H mice: at 6 months, a-wave amplitudes were increased by 100% and b-wave amplitudes by 79%. In contrast, nontransgenic mice injected with AAV5 RHO301 demonstrated a decrease in the ERG, confirming the damaging effect of rhodopsin overproduction in normal photoreceptors. In P23H mice, the increase in the ERG amplitudes was correlated with improvement of retinal structure: the thickness of the outer nuclear layer in RHO301-treated eyes was increased by 80% compared with control eyes. These findings suggest that the wild-type RHO gene can be delivered to rescue retinal degeneration in mice carrying a RHO mutation and that increased production of normal rhodopsin can suppress the effect of the mutated protein. These findings make it possible to treat ADRP caused by different mutations of RHO with the expression of wild-type RHO.
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Affiliation(s)
- Haoyu Mao
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
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Kolniak TA, Sullivan JM. Rapid, cell-based toxicity screen of potentially therapeutic post-transcriptional gene silencing agents. Exp Eye Res 2011; 92:328-37. [PMID: 21256844 DOI: 10.1016/j.exer.2011.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 12/16/2010] [Accepted: 01/12/2011] [Indexed: 11/15/2022]
Abstract
Post-transcriptional gene silencing (PTGS) agents such as antisense, ribozymes and RNA interference (RNAi) have great potential as therapeutics for a variety of eye diseases including retinal and macular degenerations, glaucoma, corneal degenerations, inflammatory and viral conditions. Despite their great potential and over thirty years of academic and corporate research only a single PTGS agent is currently approved for human therapy for a single disease. Substantial challenges exist to achieving both efficacious and safe PTGS agents. Efficacy, as measured in specific target mRNA and protein knockdown, depends upon a number of complex factors including the identification of rare regions of target mRNA accessibility, cellular co-localization of the PTGS agent in sufficient concentration with the target mRNA, and stability of the PTGS agent in the target cells in which it is delivered or expressed. Safety is commonly measured by lack of cytotoxicity or other deleterious cellular responses in cells in which the PTGS agent is delivered or expressed. To relieve major bottlenecks in RNA drug discovery novel, efficient, inexpensive, and rapid tools are needed to facilitate lead identification of the most efficacious PTGS agent, rational optimization of efficacy of the lead agent, and lead agent safety determinations. We have developed a technological platform using cell culture expression systems that permits lead identification and efficacy optimization of PTGS agents against arbitrary disease target mRNAs under relatively high throughput conditions. Here, we extend the technology platform to include PTGS safety determinations in cultured human cells that are expected to represent the common cellular housekeeping microenvironment. We developed a high throughput screening (HTS) cytotoxicity assay in 96-well plate format based around the SYTOX Green dye which is excluded from healthy viable cells and becomes substantially fluorescent only after entering cells and binding to nuclear DNA. In this format we can test a number of PTGS agents for cellular toxicity relative to control elements. We also developed an HTS 96-well plate assay that allows us to assess the impact of any given PTGS agent on stimulating a variety of common cellular stress signaling pathways (e.g. CRE, SRE, AP-1, NFκB, Myc, and NFAT) that could indicate possible deleterious effects of PTGS agents either dependent or independent of base pairing complementarity with target mRNAs. To this end we exploited the secreted alkaline phosphatase (SEAP) Pathway Profiling System where the expression of the secreted reporter protein is coupled to transcriptional activation of a variety of promoter elements involved in common cell signaling pathways. We found that a variety of lead hammerhead ribozyme (hhRz) and short hairpin (shRNA) expression constructs did not exert cytotoxicity in human cells when driven by highly active RNA Pol-III promoters. We also found that most of the cell signaling pathways tested (CRE, SRE, Myc, and NFAT) did not significantly couple through upregulation to expression of the set of PTGS agents tested. AP-1 and NFκB upregulation both appear to couple to the expression of some PTGS agents which likely reflect the known properties of these pathways to be stimulated by abundant small structured RNAs.
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Affiliation(s)
- Tiffany A Kolniak
- Department of Ophthalmology (Ross Eye Institute), University at Buffalo-SUNY, Buffalo, NY 14209, United States
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50
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Palfi A, Millington-Ward S, Chadderton N, O'Reilly M, Goldmann T, Humphries MM, Li T, Wolfrum U, Humphries P, Kenna PF, Farrar GJ. Adeno-associated virus-mediated rhodopsin replacement provides therapeutic benefit in mice with a targeted disruption of the rhodopsin gene. Hum Gene Ther 2010; 21:311-23. [PMID: 19824806 DOI: 10.1089/hum.2009.119] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rhodopsin gene (RHO) encodes a highly expressed G protein-coupled receptor that is central to visual transduction in rod photoreceptors. A suite of recombinant 2/5 adeno-associated viral (AAV) RHO replacement vectors has been generated in an attempt to recapitulate endogenous rhodopsin levels from exogenously delivered AAV vectors in the retina of mice with a targeted disruption in the rhodopsin gene (Rho(-/-) mice). Approximately 40% of wild-type mouse rhodopsin mRNA levels (RNA taken from whole retinas) was achieved in vivo in AAV-RHO-injected eyes, representing approximately 50-fold increases in expression compared with the initial vector. The main focus of this study was to test whether expression of AAV-RHO replacement in Rho(-/-) mice provided therapeutic benefit, which to date had not been achieved. Rho(-/-) mice neither elaborate rod outer segments nor have rod-derived electroretinograms (ERGs). Our results indicate for the first time in this model that subretinal AAV-RHO delivery leads not only to RHO immunolabeling but the generation of rod outer segments as evaluated by light and transmission electron microscopy. Improved histology was accompanied by rod photoreceptor activity as assessed by ERG for at least 12 weeks postinjection. The most efficient AAV-RHO constructs presented in this study provide sufficient levels of RHO to be of therapeutic benefit in Rho(-/-) mice and therefore represent important steps toward generating potent AAV-RHO replacement genes for gene therapy in RHO-linked human retinopathies.
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Affiliation(s)
- Arpad Palfi
- Department of Genetics, Trinity College Dublin, Dublin 2, Ireland.
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