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Occelli LM, Zobel L, Stoddard J, Wagner J, Pasmanter N, Querubin J, Renner LM, Reynaga R, Winkler PA, Sun K, Marinho LFLP, O'Riordan CR, Frederick A, Lauer A, Tsang SH, Hauswirth WW, McGill TJ, Neuringer M, Michalakis S, Petersen-Jones SM. Development of a translatable gene augmentation therapy for CNGB1-retinitis pigmentosa. Mol Ther 2023; 31:2028-2041. [PMID: 37056049 PMCID: PMC10362398 DOI: 10.1016/j.ymthe.2023.04.005] [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: 01/19/2023] [Revised: 03/07/2023] [Accepted: 04/10/2023] [Indexed: 04/15/2023] Open
Abstract
In this study, we investigate a gene augmentation therapy candidate for the treatment of retinitis pigmentosa (RP) due to cyclic nucleotide-gated channel beta 1 (CNGB1) mutations. We use an adeno-associated virus serotype 5 with transgene under control of a novel short human rhodopsin promoter. The promoter/capsid combination drives efficient expression of a reporter gene (AAV5-RHO-eGFP) exclusively in rod photoreceptors in primate, dog, and mouse following subretinal delivery. The therapeutic vector (AAV5-RHO-CNGB1) delivered to the subretinal space of CNGB1 mutant dogs restores rod-mediated retinal function (electroretinographic responses and vision) for at least 12 months post treatment. Immunohistochemistry shows human CNGB1 is expressed in rod photoreceptors in the treated regions as well as restoration of expression and trafficking of the endogenous alpha subunit of the rod CNG channel required for normal channel formation. The treatment reverses abnormal accumulation of the second messenger, cyclic guanosine monophosphate, which occurs in rod photoreceptors of CNGB1 mutant dogs, confirming formation of a functional CNG channel. In vivo imaging shows long-term preservation of retinal structure. In conclusion, this study establishes the long-term efficacy of subretinal delivery of AAV5-RHO-CNGB1 to rescue the disease phenotype in a canine model of CNGB1-RP, confirming its suitability for future clinical development.
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Affiliation(s)
- Laurence M Occelli
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Lena Zobel
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany; Department of Ophthalmology, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Jonathan Stoddard
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA
| | - Johanna Wagner
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Nathaniel Pasmanter
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Janice Querubin
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Lauren M Renner
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA
| | - Rene Reynaga
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA
| | - Paige A Winkler
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Kelian Sun
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Luis Felipe L P Marinho
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | | | - Amy Frederick
- Genomic Medicine Unit, Sanofi, 225 Second Avenue, Waltham, MA 02451, USA
| | - Andreas Lauer
- Casey Eye Institute, Oregon Health & Science University, 515 Campus Drive, Portland, OR 97239, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Columbia Stem Cell Initiative, Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - William W Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Box 100284 HSC, Gainesville, FL 32610, USA
| | - Trevor J McGill
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA; Casey Eye Institute, Oregon Health & Science University, 515 Campus Drive, Portland, OR 97239, USA
| | - Martha Neuringer
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA; Casey Eye Institute, Oregon Health & Science University, 515 Campus Drive, Portland, OR 97239, USA
| | - Stylianos Michalakis
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany; Department of Ophthalmology, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Simon M Petersen-Jones
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA.
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Gene Therapy with Voretigene Neparvovec Improves Vision and Partially Restores Electrophysiological Function in Pre-School Children with Leber Congenital Amaurosis. Biomedicines 2022; 11:biomedicines11010103. [PMID: 36672611 PMCID: PMC9855623 DOI: 10.3390/biomedicines11010103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/20/2022] [Accepted: 12/24/2022] [Indexed: 01/03/2023] Open
Abstract
Leber congenital amaurosis caused by mutations in the RPE65 gene belongs to the most severe early-onset hereditary childhood retinopathies naturally progressing to legal blindness. The novel gene therapy voretigene neparvovec is the first approved causative treatment option for this devastating eye disease and is specifically designed to treat RPE65-mediated retinal dystrophies. Herein, we present a follow-up of the youngest treated patients in Germany so far, including four pre-school children who received treatment with voretigene neparvovec at a single treatment center between January 2020 and May 2022. All patients underwent pars plana vitrectomy with circumferential peeling of the internal limiting membrane at the injection site and subretinal injection of voretigene neparvovec. Pre- and postoperative diagnostics included imaging (spectral domain optical coherence tomography, fundus autofluorescence, fundus wide-angle imaging), electrophysiologic examination (ERG), retinal light sensitivity measurements (FST) and visual acuity testing. Behavioral changes were assessed using a questionnaire and by observing the children's vision-guided behavior in different levels of illumination. All children showed marked increase in vision-guided behavior shortly after therapy, as well as marked increase in visual acuity in the postoperative course up to full visual acuity in one child. Two eyes showed partial electrophysiological recovery of an ERG that was undetectable before treatment-a finding that has not been described in humans before.
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Pasmanter N, Petersen-Jones SM. Characterization of scotopic and mesopic rod signaling pathways in dogs using the On-Off electroretinogram. BMC Vet Res 2022; 18:422. [PMID: 36463174 PMCID: PMC9719241 DOI: 10.1186/s12917-022-03505-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/07/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND The On-Off, or long flash, full field electroretinogram (ERG) separates retinal responses to flash onset and offset. Depending on degree of dark-adaptation and stimulus strength the On and Off ERG can be shaped by rod and cone photoreceptors and postreceptoral cells, including ON and OFF bipolar cells. Interspecies differences have been shown, with predominantly positive Off-response in humans and other primates and a negative Off-response in rodents and dogs. However, the rod signaling pathways that contribute to these differential responses have not been characterized. In this study, we designed a long flash protocol in the dog that varied in background luminance and stimulus strength allowing for some rod components to be present to better characterize how rod pathways vary from scotopic to mesopic conditions. RESULTS With low background light the rod a-wave remains while the b-wave is significantly reduced resulting in a predominantly negative waveform in mesopic conditions. Through modeling and subtraction of the rod-driven response, we show that rod bipolar cells saturate with dimmer backgrounds than rod photoreceptors, resulting in rod hyperpolarization contributing to a large underlying negativity with mesopic backgrounds. CONCLUSIONS Reduction in rod bipolar cell responses in mesopic conditions prior to suppression of rod photoreceptor responses may reflect the changes in signaling pathway of rod-driven responses needed to extend the range of lighting conditions over which the retina functions.
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Affiliation(s)
- Nate Pasmanter
- grid.17088.360000 0001 2150 1785Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D208 East Lansing, MI USA
| | - Simon M. Petersen-Jones
- grid.17088.360000 0001 2150 1785Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D208 East Lansing, MI USA
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Abstract
PURPOSE Mutations in the cyclic nucleotide-gated (CNG) channel beta subunit (CNGB1) are an important cause of recessive retinitis pigmentosa. We identified a large animal model with a truncating mutation of CNGB1. This study reports the persistence of small, desensitized rod ERG responses in this model. METHODS Dark-, light-adapted and chromatic ERGs were recorded in CNGB1 mutant dogs and age and breed matched controls. Comparisons were made with a dog model known to completely lack rod function; young dogs with a mutation in the rod phosphodiesterase 6 alpha subunit (PDE6A-/-). Immunohistochemistry (IHC) to label the rod CNG alpha (CNGA1) and CNGB1 subunits was performed. RESULTS The dark-adapted ERG of CNGB1 mutant dogs had a raised response threshold with lack of normal rod response and a remaining cone response. Increasing stimulus strength resulted in the appearance of a separate, slower positive waveform following the dark-adapted cone b-wave. With increasing stimulus strength this increased in amplitude and became faster to merge with the initial b-wave. Comparison of responses from PDE6A-/- (cone only dogs) with CNGB1 mutant dogs to red and blue flashes and between dark-adapted and light-adapted responses supported the hypothesis that the CNGB1 mutant dog had residual desensitized rod responses. CNGB1 mutant dogs had a small amount of CNGA1 detectable in the outer segments. CONCLUSIONS CNGB1 mutant dogs have a residual ERG response from desensitized rods. This may be due to low levels of CNGA1 in outer segments.
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Serotype-specific transduction of canine joint tissue explants and cultured monolayers by self-complementary adeno-associated viral vectors. Gene Ther 2022; 30:398-404. [PMID: 36261499 DOI: 10.1038/s41434-022-00366-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/04/2022] [Accepted: 09/14/2022] [Indexed: 11/08/2022]
Abstract
A formal screening of self-complementary adeno-associated virus (scAAV) vector serotypes in canine joint tissues has not been performed to date. Selecting appropriate serotypes is crucial for successful treatment due to their varying levels of tissue tropism. The objective of this study is to identify the most optimal scAAV vector serotype that maximizes transduction efficiencies in canine cell monolayer cultures (chondrocytes, synoviocytes, and mesenchymal stem cells) and tissue explant cultures (cartilage and synovium). Transduction efficiencies of scAAV serotypes 1, 2, 2.5, 3, 4, 5, 6, 8, and 9 were evaluated in each culture type in three different vector concentrations by encoding a green fluorescent protein. It was found that scAAV2 and 2.5 showed the overall highest transduction efficiency among serotypes with dose-response. Since possible immune response against conventional AAV2 was previously reported in dogs, the chimeric scAAV2.5 may be more suitable to use. Evaluation of the safety and efficacy of the scAAV2.5 vector with an appropriate therapeutic gene in vivo is indicated.
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Petersen-Jones SM, Pasmanter N, Occelli LM, Gervais KJ, Mowat FM, Querubin J, Winkler PA. An unusual inherited electroretinogram feature with an exaggerated negative component in dogs. Vet Ophthalmol 2022; 25:385-397. [PMID: 35713167 PMCID: PMC9540982 DOI: 10.1111/vop.12998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/16/2022] [Accepted: 05/23/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To assess an inherited abnormal negative response electroretinogram (NRE) that originated in a family of Papillon dogs. ANIMALS STUDIED Thirty-eight dogs (Papillons, or Papillon cross Beagles or Beagles). PROCEDURES Dogs underwent routine ophthalmic examination and a detailed dark-adapted, light-adapted and On-Off electroretinographic study. Vision was assessed using a four-choice exit device. Spectral-domain optical coherence tomography (SD-OCT) was performed on a subset of dogs. Two affected males were outcrossed to investigate the mode of inheritance of the phenotype. RESULTS The affected dogs had an increased underlying negative component to the ERG. This was most pronounced in the light-adapted ERG, resulting in a reduced b-wave and an exaggerated photopic negative response (PhNR). Changes were more pronounced with stronger flashes. Similarly, the On-response of the On-Off ERG had a reduced b-wave and a large post-b-wave negative component. The dark-adapted ERG had a significant increase in the scotopic threshold response (STR) and a significant reduction in the b:a-wave ratio. Significant changes could be detected at 2 months of age but became more pronounced with age. Vision testing using a four-choice device showed affected dogs had reduced visual performance under the brightest light condition. There was no evidence of a degenerative process in the affected dogs up to 8.5 years of age. Test breeding results suggested the NRE phenotype had an autosomal dominant mode of inheritance. CONCLUSIONS We describe an inherited ERG phenotype in Papillon dogs characterized by an underlying negative component affecting both dark- and light-adapted ERG responses.
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Affiliation(s)
- Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Nate Pasmanter
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Laurence M Occelli
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Kristen J Gervais
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA.,South Shore Animal Hospital, Boston, Massachusetts, USA
| | - Freya M Mowat
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA.,Department of Surgical Sciences School of Veterinary Medicine, and Department of Ophthalmology and Visual Sciences School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Janice Querubin
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Paige A Winkler
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
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Pasmanter N, Occelli LM, Komáromy AM, Petersen-Jones SM. Use of extended protocols with nonstandard stimuli to characterize rod and cone contributions to the canine electroretinogram. Doc Ophthalmol 2022; 144:81-97. [PMID: 35247111 PMCID: PMC10426558 DOI: 10.1007/s10633-022-09866-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 02/08/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE In this study, we assessed several extended electroretinographic protocols using nonstandard stimuli. Our aim was to separate and quantify the contributions of different populations of retinal cells to the overall response, both to assess normal function and characterize dogs with inherited retinal disease. METHODS We investigated three different protocols for measuring the full-field flash electroretinogram-(1) chromatic dark-adapted red and blue flashes, (2) increasing luminance blue-background, (3) flicker with fixed frequency and increasing luminance, and flicker with increasing frequency at a fixed luminance-to assess rod and cone contributions to electroretinograms recorded in phenotypically normal control dogs and dogs lacking rod function. RESULTS Temporal separation of the rod- and cone-driven responses is possible in the fully dark-adapted eye using dim red flashes. A- and b-wave amplitudes decrease at different rates with increasing background luminance in control dogs. Flicker responses elicited with extended flicker protocols are well fit with mathematical models in control dogs. Dogs lacking rod function demonstrated larger amplitude dark-adapted compared to light-adapted flicker responses. CONCLUSIONS Using extended protocols of the full-field electroretinogram provides additional characterization of the health and function of different populations of cells in the normal retina and enables quantifiable comparison between phenotypically normal dogs and those with retinal disease.
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Affiliation(s)
- Nate Pasmanter
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA
| | - Laurence M Occelli
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA
| | - András M Komáromy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA.
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Català P, Thuret G, Skottman H, Mehta JS, Parekh M, Ní Dhubhghaill S, Collin RWJ, Nuijts RMMA, Ferrari S, LaPointe VLS, Dickman MM. Approaches for corneal endothelium regenerative medicine. Prog Retin Eye Res 2021; 87:100987. [PMID: 34237411 DOI: 10.1016/j.preteyeres.2021.100987] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 12/13/2022]
Abstract
The state of the art therapy for treating corneal endothelial disease is transplantation. Advances in the reproducibility and accessibility of surgical techniques are increasing the number of corneal transplants, thereby causing a global deficit of donor corneas and leaving 12.7 million patients with addressable visual impairment. Approaches to regenerate the corneal endothelium offer a solution to the current tissue scarcity and a treatment to those in need. Methods for generating corneal endothelial cells into numbers that could address the current tissue shortage and the possible strategies used to deliver them have now become a therapeutic reality with clinical trials taking place in Japan, Singapore and Mexico. Nevertheless, there is still a long way before such therapies are approved by regulatory bodies and become clinical practice. Moreover, acellular corneal endothelial graft equivalents and certain drugs could provide a treatment option for specific disease conditions without the need of donor tissue or cells. Finally, with the emergence of gene modulation therapies to treat corneal endothelial disease, it would be possible to treat presymptomatic patients or those presenting early symptoms, drastically reducing the need for donor tissue. It is necessary to understand the most recent developments in this rapidly evolving field to know which conditions could be treated with which approach. This article provides an overview of the current and developing regenerative medicine therapies to treat corneal endothelial disease and provides the necessary guidance and understanding towards the treatment of corneal endothelial disease.
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Affiliation(s)
- Pere Català
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands; Department of Cell Biology-Inspired Tissue Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, the Netherlands
| | - Gilles Thuret
- Laboratory of Biology, Engineering and Imaging of Corneal Graft, BiiGC, Faculty of Medicine, University of Saint Etienne, Saint Etienne, France; Institut Universitaire de France, Paris, France
| | - Heli Skottman
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Jodhbir S Mehta
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore; Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-National University Singapore Medical School, Singapore; Singapore National Eye Centre, Singapore
| | - Mohit Parekh
- Institute of Ophthalmology, University College London, London, UK; The Veneto Eye Bank Foundation, Venice, Italy; Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Sorcha Ní Dhubhghaill
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium; Ophthalmology, Visual Optics and Visual Rehabilitation, Department of Translational Neurosciences, University of Antwerp, Wilrijk, Belgium
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Rudy M M A Nuijts
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands
| | | | - Vanessa L S LaPointe
- Department of Cell Biology-Inspired Tissue Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, the Netherlands
| | - Mor M Dickman
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands; Department of Cell Biology-Inspired Tissue Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, the Netherlands.
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Abstract
Inherited retinal diseases (IRDs) are an important cause of blindness worldwide. Over 270 genes have been associated with IRD. Genetic testing can determine the cause of the clinical disease in the majority of patients. However, at least 25-50% of patients with clinical diagnosis of IRD remain unsolved even after whole genome sequencing. Animal models of IRD can be useful for expanding the set of established IRD genes, to gain biological understanding of the function of these genes in the retina, and to test advanced therapeutics prior to human clinical trials. In this chapter some small and large animal models of IRD are discussed including some of the advantages and limitations of each for various forms of retinopathy.
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Chiu W, Lin TY, Chang YC, Isahwan-Ahmad Mulyadi Lai H, Lin SC, Ma C, Yarmishyn AA, Lin SC, Chang KJ, Chou YB, Hsu CC, Lin TC, Chen SJ, Chien Y, Yang YP, Hwang DK. An Update on Gene Therapy for Inherited Retinal Dystrophy: Experience in Leber Congenital Amaurosis Clinical Trials. Int J Mol Sci 2021; 22:ijms22094534. [PMID: 33926102 PMCID: PMC8123696 DOI: 10.3390/ijms22094534] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/22/2021] [Indexed: 12/20/2022] Open
Abstract
Inherited retinal dystrophies (IRDs) are a group of rare eye diseases caused by gene mutations that result in the degradation of cone and rod photoreceptors or the retinal pigment epithelium. Retinal degradation progress is often irreversible, with clinical manifestations including color or night blindness, peripheral visual defects and subsequent vision loss. Thus, gene therapies that restore functional retinal proteins by either replenishing unmutated genes or truncating mutated genes are needed. Coincidentally, the eye’s accessibility and immune-privileged status along with major advances in gene identification and gene delivery systems heralded gene therapies for IRDs. Among these clinical trials, voretigene neparvovec-rzyl (Luxturna), an adeno-associated virus vector-based gene therapy drug, was approved by the FDA for treating patients with confirmed biallelic RPE65 mutation-associated Leber Congenital Amaurosis (LCA) in 2017. This review includes current IRD gene therapy clinical trials and further summarizes preclinical studies and therapeutic strategies for LCA, including adeno-associated virus-based gene augmentation therapy, 11-cis-retinal replacement, RNA-based antisense oligonucleotide therapy and CRISPR-Cas9 gene-editing therapy. Understanding the gene therapy development for LCA may accelerate and predict the potential hurdles of future therapeutics translation. It may also serve as the template for the research and development of treatment for other IRDs.
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Affiliation(s)
- Wei Chiu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; (W.C.); (S.-C.L.); (S.-C.L.); (K.-J.C.); (Y.-B.C.); (C.-C.H.)
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
| | - Ting-Yi Lin
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- School of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Yun-Chia Chang
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
| | - Henkie Isahwan-Ahmad Mulyadi Lai
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Shen-Che Lin
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; (W.C.); (S.-C.L.); (S.-C.L.); (K.-J.C.); (Y.-B.C.); (C.-C.H.)
| | - Chun Ma
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Department of Medicine, National Taiwan University, Taipei 10617, Taiwan
| | - Aliaksandr A. Yarmishyn
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
| | - Shiuan-Chen Lin
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; (W.C.); (S.-C.L.); (S.-C.L.); (K.-J.C.); (Y.-B.C.); (C.-C.H.)
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
| | - Kao-Jung Chang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; (W.C.); (S.-C.L.); (S.-C.L.); (K.-J.C.); (Y.-B.C.); (C.-C.H.)
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Yu-Bai Chou
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; (W.C.); (S.-C.L.); (S.-C.L.); (K.-J.C.); (Y.-B.C.); (C.-C.H.)
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
| | - Chih-Chien Hsu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; (W.C.); (S.-C.L.); (S.-C.L.); (K.-J.C.); (Y.-B.C.); (C.-C.H.)
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
| | - Tai-Chi Lin
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
| | - Shih-Jen Chen
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
| | - Yueh Chien
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Division of Basic Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
- Correspondence: (Y.C.); (Y.-P.Y.); (D.-K.H.)
| | - Yi-Ping Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Division of Basic Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
- Institute of Food Safety and Health Risk Assessment, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
- Correspondence: (Y.C.); (Y.-P.Y.); (D.-K.H.)
| | - De-Kuang Hwang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (T.-Y.L.); (H.I.-A.M.L.); (C.M.); (A.A.Y.); (T.-C.L.); (S.-J.C.)
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
- Correspondence: (Y.C.); (Y.-P.Y.); (D.-K.H.)
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11
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Peters CW, Maguire CA, Hanlon KS. Delivering AAV to the Central Nervous and Sensory Systems. Trends Pharmacol Sci 2021; 42:461-474. [PMID: 33863599 DOI: 10.1016/j.tips.2021.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 12/13/2022]
Abstract
As gene therapy enters mainstream medicine, it is more important than ever to have a grasp of exactly how to leverage it for maximum benefit. The development of new targeting strategies and tools makes treating patients with genetic diseases possible. Many Mendelian disorders are amenable to gene replacement or correction. These often affect post-mitotic tissues, meaning that a single stably expressing therapy can be applied. Recent years have seen the development of a large number of novel viral vectors for delivering specific therapies. These new vectors - predominately recombinant adeno-associated virus (AAV) variants - target nervous tissues with differing efficiencies. This review gives an overview of current gene therapies in the brain, ear, and eye, and describes the optimal approaches, depending on cell type and transgene. Overall, this work aims to serve as a primer for gene therapy in the central nervous and sensory systems.
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Affiliation(s)
- Cole W Peters
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Casey A Maguire
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Killian S Hanlon
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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12
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ERG assessment of altered retinal function in canine models of retinitis pigmentosa and monitoring of response to translatable gene augmentation therapy. Doc Ophthalmol 2021; 143:171-184. [PMID: 33818677 DOI: 10.1007/s10633-021-09832-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE To analyze ERG responses from two dog models of retinitis pigmentosa, one due to a PDE6A mutation and the other a CNGB1 mutation, both to assess the effect of these mutations on retinal function and the ability of gene augmentation therapy to restore normal function. METHODS Scotopic and photopic ERGs from young affected and normal control dogs and affected dogs following AAV-mediated gene augmentation therapy were analyzed. Parameters reflecting rod and cone function were collected by modeling the descending slope of the a-wave to measure receptor response and sensitivity. Rod-driven responses were further assessed by Naka-Rushton fitting of the first limb of the scotopic b-wave luminance-response plot. RESULTS PDE6A-/- dogs showed a dramatic decrease in rod-driven responses with very reduced rod maximal responses and sensitivity. There was a minor reduction in the amplitude of maximal cone responses. In contrast, CNGB1-/- dogs had some residual rod responses with reduced amplitude and sensitivity and normal cone responses. Following gene augmentation therapy, rod parameters were substantially improved in both models with restoration of sensitivity parameters log S and log K and a large increase in log Rmax in keeping with rescue of normal rod phototransduction in the treated retinal regions. CONCLUSIONS Modeling of rod and cone a-waves and the luminance-response function of the scotopic b-wave characterized the loss of rod photoreceptor function in two dog models of retinitis pigmentosa and showed the effectiveness of gene augmentation therapy in restoring normal functional parameters.
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13
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Padhy SK, Takkar B, Narayanan R, Venkatesh P, Jalali S. Voretigene Neparvovec and Gene Therapy for Leber's Congenital Amaurosis: Review of Evidence to Date. APPLICATION OF CLINICAL GENETICS 2020; 13:179-208. [PMID: 33268999 PMCID: PMC7701157 DOI: 10.2147/tacg.s230720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022]
Abstract
Gene therapy has now evolved as the upcoming modality for management of many disorders, both inheritable and non-inheritable. Knowledge of genetics pertaining to a disease has therefore become paramount for physicians across most specialities. Inheritable retinal dystrophies (IRDs) are notorious for progressive and relentless vision loss, frequently culminating in complete blindness in both eyes. Leber’s congenital amaurosis (LCA) is a typical example of an IRD that manifests very early in childhood. Research in gene therapy has led to the development and approval of voretigene neparvovec (VN) for use in patients of LCA with a deficient biallelic RPE65 gene. The procedure involves delivery of a recombinant virus vector that carries the RPE65 gene in the subretinal space. This comprehensive review reports the evidence thus far in support of gene therapy for LCA. We explore and compare the various gene targets including but not limited to RPE65, and discuss the choice of vector and method for ocular delivery. The review details the evolution of gene therapy with VN in a phased manner, concluding with the challenges that lie ahead for its translation for use in communities that differ much both genetically and economically.
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Affiliation(s)
- Srikanta Kumar Padhy
- Vitreoretina and Uveitis Services, L V Prasad Eye Institute, Mithu Tulsi Chanrai Campus, Bhubaneswar, India
| | - Brijesh Takkar
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India.,Center of Excellence for Rare Eye Diseases, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
| | - Raja Narayanan
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India
| | - Pradeep Venkatesh
- Dr RP Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Subhadra Jalali
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India.,Jasti V. Ramanamma Childrens' Eye Care Centre, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
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14
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Tay LS, Palmer N, Panwala R, Chew WL, Mali P. Translating CRISPR-Cas Therapeutics: Approaches and Challenges. CRISPR J 2020; 3:253-275. [PMID: 32833535 PMCID: PMC7469700 DOI: 10.1089/crispr.2020.0025] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
CRISPR-Cas clinical trials have begun, offering a first glimpse at how DNA and RNA targeting could enable therapies for many genetic and epigenetic human diseases. The speedy progress of CRISPR-Cas from discovery and adoption to clinical use is built on decades of traditional gene therapy research and belies the multiple challenges that could derail the successful translation of these new modalities. Here, we review how CRISPR-Cas therapeutics are translated from technological systems to therapeutic modalities, paying particular attention to the therapeutic cascade from cargo to delivery vector, manufacturing, administration, pipelines, safety, and therapeutic target profiles. We also explore potential solutions to some of the obstacles facing successful CRISPR-Cas translation. We hope to illuminate how CRISPR-Cas is brought from the academic bench toward use in the clinic.
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Affiliation(s)
- Lavina Sierra Tay
- Laboratory of Synthetic Biology and Genome Editing Therapeutics, Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Nathan Palmer
- Division of Biological Sciences, University of California San Diego, La Jolla, California, USA
| | - Rebecca Panwala
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Wei Leong Chew
- Laboratory of Synthetic Biology and Genome Editing Therapeutics, Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Prashant Mali
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
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15
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Winkler PA, Occelli LM, Petersen-Jones SM. Large Animal Models of Inherited Retinal Degenerations: A Review. Cells 2020; 9:cells9040882. [PMID: 32260251 PMCID: PMC7226744 DOI: 10.3390/cells9040882] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Studies utilizing large animal models of inherited retinal degeneration (IRD) have proven important in not only the development of translational therapeutic approaches, but also in improving our understanding of disease mechanisms. The dog is the predominant species utilized because spontaneous IRD is common in the canine pet population. Cats are also a source of spontaneous IRDs. Other large animal models with spontaneous IRDs include sheep, horses and non-human primates (NHP). The pig has also proven valuable due to the ease in which transgenic animals can be generated and work is ongoing to produce engineered models of other large animal species including NHP. These large animal models offer important advantages over the widely used laboratory rodent models. The globe size and dimensions more closely parallel those of humans and, most importantly, they have a retinal region of high cone density and denser photoreceptor packing for high acuity vision. Laboratory rodents lack such a retinal region and, as macular disease is a critical cause for vision loss in humans, having a comparable retinal region in model species is particularly important. This review will discuss several large animal models which have been used to study disease mechanisms relevant for the equivalent human IRD.
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16
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Weed L, Ammar MJ, Zhou S, Wei Z, Serrano LW, Sun J, Lee V, Maguire AM, Bennett J, Aleman TS. Safety of Same-Eye Subretinal Sequential Readministration of AAV2-hRPE65v2 in Non-human Primates. Mol Ther Methods Clin Dev 2019; 15:133-148. [PMID: 31660416 PMCID: PMC6807311 DOI: 10.1016/j.omtm.2019.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 08/26/2019] [Indexed: 01/28/2023]
Abstract
We have demonstrated safe and effective subretinal readministration of recombinant adeno-associated virus serotype (rAAV) to the contralateral eye in large animals and humans even in the setting of preexisting neutralizing antibodies (NAbs). Readministration of AAV to the same retina may be desirable in order to treat additional areas of the retina not targeted initially or to boost transgene expression levels at a later time point. To better understand the immune and structural consequences of subretinal rAAV readministration to the same eye, we administered bilateral subretinal injections of rAAV2-hRPE65v2 to three unaffected non-human primates (NHPs) and repeated the injections in those same eyes 2 months later. Ophthalmic exams and retinal imaging were performed after the first and second injections. Peripheral blood monocytes, serum, and intraocular fluids were collected at baseline and post-injection time points to characterize the cellular and humoral immune responses. Histopathologic and immunohistochemical studies were carried out on the treated retinas. Ipsilateral readministration of AAV2-hRPE65v2 in NHPs did not threaten the ocular or systemic health through the time span of the study. The repeat injections were immunologically and structurally well tolerated, even in the setting of preexisting serum NAbs. Localized structural abnormalities confined to the outer retina and retinal pigmented epithelium (RPE) after readministration of the treatment do not differ from those observed after single or contralateral administration of an AAV carrying a non-therapeutic transgene in NHPs and were not observed in a patient treated with the nearly identical, FDA-approved, AAV2-hRPE65v2 vector (voretigene neparvovec-rzyl), suggesting NHP-specific abnormalities.
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Affiliation(s)
- Lindsey Weed
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Michael J. Ammar
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Shangzhen Zhou
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Zhangyong Wei
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Leona W. Serrano
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Junwei Sun
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Vivian Lee
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Dermatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Albert M. Maguire
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Dermatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- The Children’s Hospital of Philadelphia (CHOP), Philadelphia, PA, USA
| | - Tomas S. Aleman
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- The Children’s Hospital of Philadelphia (CHOP), Philadelphia, PA, USA
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17
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Ramlogan-Steel CA, Murali A, Andrzejewski S, Dhungel B, Steel JC, Layton CJ. Gene therapy and the adeno-associated virus in the treatment of genetic and acquired ophthalmic diseases in humans: Trials, future directions and safety considerations. Clin Exp Ophthalmol 2019; 47:521-536. [PMID: 30345694 DOI: 10.1111/ceo.13416] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/04/2018] [Accepted: 10/15/2018] [Indexed: 12/27/2022]
Abstract
Voretigene neparvovec-rzyl was recently approved for the treatment of Leber congenital amaurosis, and the use of gene therapy for eye disease is attracting even greater interest. The eye has immune privileged status, is easily accessible, requires a reduced dosage of therapy due to its size and is highly compartmentalized, significantly reducing systemic spread. Adeno-associated virus (AAV), with its low pathogenicity, prolonged expression profile and ability to transduce multiple cell types, has become the leading gene therapy vector. Target diseases have moved beyond currently untreatable inherited dystrophies to common, partially treatable acquired conditions such as exudative age-related macular degeneration and glaucoma, but use of the technology in these conditions imposes added obligations for caution in vector design. This review discusses the current status of AAV gene therapy trials in genetic and acquired ocular diseases, and explores new scientific developments, which could help ensure effective and safe use of the therapy in the future.
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Affiliation(s)
- Charmaine A Ramlogan-Steel
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia.,Medical and Applied Science, Central Queensland University, School of Health, Rockhampton, Australia
| | - Aparna Murali
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
| | - Slawomir Andrzejewski
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
| | - Bijay Dhungel
- Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
| | - Jason C Steel
- Medical and Applied Science, Central Queensland University, School of Health, Rockhampton, Australia
| | - Christopher J Layton
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
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18
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Gao S, Kahremany S, Zhang J, Jastrzebska B, Querubin J, Petersen-Jones SM, Palczewski K. Retinal-chitosan Conjugates Effectively Deliver Active Chromophores to Retinal Photoreceptor Cells in Blind Mice and Dogs. Mol Pharmacol 2018; 93:438-452. [PMID: 29453250 DOI: 10.1124/mol.117.111294] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
The retinoid (visual) cycle consists of a series of biochemical reactions needed to regenerate the visual chromophore 11-cis-retinal and sustain vision. Genetic or environmental factors affecting chromophore production can lead to blindness. Using animal models that mimic human retinal diseases, we previously demonstrated that mechanism-based pharmacological interventions can maintain vision in otherwise incurable genetic diseases of the retina. Here, we report that after 9-cis-retinal administration to lecithin:retinol acyltransferase-deficient (Lrat-/- ) mice, the drug was rapidly absorbed and then cleared within 1 to 2 hours. However, when conjugated to form chitosan-9-cis-retinal, this prodrug was slowly absorbed from the gastrointestinal tract, resulting in sustainable plasma levels of 9-cis-retinol and recovery of visual function without causing elevated levels, as occurs with unconjugated drug treatment. Administration of chitosan-9-cis-retinal conjugate intravitreally in retinal pigment epithelium-specific 65 retinoid isomerase (RPE65)-deficient dogs improved photoreceptor function as assessed by electroretinography. Functional rescue was dose dependent and maintained for several weeks. Dosing via the gastrointestinal tract in canines was found ineffective, most likely due to peculiarities of vitamin A blood transport in canines. Use of the chitosan conjugate in combination with 11-cis-6-ring-retinal, a locked ring analog of 11-cis-retinal that selectively blocks rod opsin consumption of chromophore while largely sparing cone opsins, was found to prolong cone vision in Lrat-/- mice. Development of such combination low-dose regimens to selectively prolong useful cone vision could not only expand retinal disease treatments to include Leber congenital amaurosis but also the age-related decline in human dark adaptation from progressive retinoid cycle deficiency.
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Affiliation(s)
- Songqi Gao
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Shirin Kahremany
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Jianye Zhang
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Beata Jastrzebska
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Janice Querubin
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Simon M Petersen-Jones
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Krzysztof Palczewski
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
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19
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Miller WW, Parisi D. Development and validation of the canine visual function instrument. Vet Ophthalmol 2018; 21:586-594. [PMID: 29380502 DOI: 10.1111/vop.12551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE In this study, we created the Canine Visual Function Instrument (CVFI) and tested its validity and reliability for assessing the quality of vision of dogs. METHODS We used Cronbach's alpha to test the strength of the consistency of the questions in the instrument and factor analysis to assess whether the questions achieved unidimensionality in the measurement of dogs' vision quality. RESULTS Our analysis shows that the CVFI is a valid and reliable tool to seek self-reported observations about dogs' vision quality from owners. Our results also show that the vision quality scale has high empirical validity and therefore can be used to determine whether a dog has normal vision or moderate or serious visual impairments. CONCLUSION The CVFI might have important practical applications in the field of veterinary ophthalmology in two important ways. First, it can be used to determine whether the treatment of dogs with visual impairment improves vision quality. Second, it can be used as a warning system to alert owners about their dogs' quality of vision.
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Affiliation(s)
| | - Domenico Parisi
- Department of Sociology, Mississippi State University, Mississippi, MS, USA
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20
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Occelli LM, Schön C, Seeliger MW, Biel M, Michalakis S, Petersen-Jones SM. Gene Supplementation Rescues Rod Function and Preserves Photoreceptor and Retinal Morphology in Dogs, Leading the Way Toward Treating Human PDE6A-Retinitis Pigmentosa. Hum Gene Ther 2017; 28:1189-1201. [PMID: 29212382 DOI: 10.1089/hum.2017.155] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mutations in the phosphodiesterase 6A gene (PDE6A) result in retinitis pigmentosa (RP) type 43 (RP43) and are responsible for about 4% of autosomal recessive RP. There is currently no treatment for this blinding condition. The aim of this project was to use a large-animal model to test a gene supplementation viral vector designed to be translated for use in a clinical trial for the treatment of RP43. Seven Pde6a-/- puppies were given sub-retinal injections of an adeno-associated viral vector (AAV) serotype 2/8 delivering human PDE6A cDNA under control of a short rhodopsin promoter (AAV8-PDE6A). Three puppies received ∼1 × 1011 vg in one eye and four puppies ∼5 × 1011 vg/per eye, with both eyes being injected in two animals. In vivo outcome measures included vision testing and electroretinography (ERG), as well as fundus and spectral domain-optical coherence tomography imaging. Some puppies were euthanized and their eyes processed for immunohistochemistry. All puppies had improved rod-mediated vision in the treated eye. ERGs showed improved rod-mediated responses in the higher-dose group but in only one of the lower-dose group animals. Receptor+ thickness was preserved and photoreceptor morphology improved in the treated retinal regions in all puppies. Treatment resulted in PDE6A transgene expression, accompanied by much increased levels of Pde6b, in rod outer segments in the injected retinal regions. There were several indications of improved retinal health in the PDE6A-expressing regions, including lack of abnormal cyclic guanosine monophosphate accumulation, appropriate rod opsin localization to the outer segments with a large reduction in mislocalization to other regions of the rod cell, and reduced Müller cell activation. Additionally, cone photoreceptors showed morphological improvement in the treated region, with normal-appearing inner and outer segments. AAV8-PDE6A gene supplementation therapy restored rod vision in Pde6a-/- puppies and preserved retinal morphology. These positive outcomes are an important step toward a human clinical trial to treat PDE6A-RP.
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Affiliation(s)
- Laurence M Occelli
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, Michigan
| | - Christian Schön
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Mathias W Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Tuebingen, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, Michigan
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21
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Petersen-Jones SM, Occelli LM, Winkler PA, Lee W, Sparrow JR, Tsukikawa M, Boye SL, Chiodo V, Capasso JE, Becirovic E, Schön C, Seeliger MW, Levin AV, Michalakis S, Hauswirth WW, Tsang SH. Patients and animal models of CNGβ1-deficient retinitis pigmentosa support gene augmentation approach. J Clin Invest 2017; 128:190-206. [PMID: 29202463 PMCID: PMC5749539 DOI: 10.1172/jci95161] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 10/10/2017] [Indexed: 01/07/2023] Open
Abstract
Retinitis pigmentosa (RP) is a major cause of blindness that affects 1.5 million people worldwide. Mutations in cyclic nucleotide-gated channel β 1 (CNGB1) cause approximately 4% of autosomal recessive RP. Gene augmentation therapy shows promise for treating inherited retinal degenerations; however, relevant animal models and biomarkers of progression in patients with RP are needed to assess therapeutic outcomes. Here, we evaluated RP patients with CNGB1 mutations for potential biomarkers of progression and compared human phenotypes with those of mouse and dog models of the disease. Additionally, we used gene augmentation therapy in a CNGβ1-deficient dog model to evaluate potential translation to patients. CNGB1-deficient RP patients and mouse and dog models had a similar phenotype characterized by early loss of rod function and slow rod photoreceptor loss with a secondary decline in cone function. Advanced imaging showed promise for evaluating RP progression in human patients, and gene augmentation using adeno-associated virus vectors robustly sustained the rescue of rod function and preserved retinal structure in the dog model. Together, our results reveal an early loss of rod function in CNGB1-deficient patients and a wide window for therapeutic intervention. Moreover, the identification of potential biomarkers of outcome measures, availability of relevant animal models, and robust functional rescue from gene augmentation therapy support future work to move CNGB1-RP therapies toward clinical trials.
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Affiliation(s)
- Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Laurence M Occelli
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Paige A Winkler
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Winston Lee
- Department of Ophthalmology Pathology & Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Janet R Sparrow
- Department of Ophthalmology Pathology & Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Mai Tsukikawa
- Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Sanford L Boye
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Vince Chiodo
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Jenina E Capasso
- Ocular Genetics, Wills Eye Hospital (WEH), Philadelphia, Pennsylvania, USA
| | - Elvir Becirovic
- Center for Integrated Protein Science Munich (CIPSM), Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Christian Schön
- Center for Integrated Protein Science Munich (CIPSM), Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Mathias W Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Alex V Levin
- Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Ocular Genetics, Wills Eye Hospital (WEH), Philadelphia, Pennsylvania, USA
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich (CIPSM), Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Stephen H Tsang
- Department of Ophthalmology Pathology & Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, New York, USA.,Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center (CUMC), Edward S. Harkness Eye Institute, New York, New York, USA
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22
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Evaluation of tolerance to lentiviral LV-RPE65 gene therapy vector after subretinal delivery in non-human primates. Transl Res 2017; 188:40-57.e4. [PMID: 28754419 DOI: 10.1016/j.trsl.2017.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 04/30/2017] [Accepted: 06/30/2017] [Indexed: 12/17/2022]
Abstract
Several approaches have been developed for gene therapy in RPE65-related Leber congenital amaurosis. To date, strategies that have reached the clinical stages rely on adeno-associated viral vectors and two of them documented limited long-term effect. We have developed a lentiviral-based strategy of RPE65 gene transfer that efficiently restored protein expression and cone function in RPE65-deficient mice. In this study, we evaluated the ocular and systemic tolerances of this lentiviral-based therapy (LV-RPE65) on healthy nonhuman primates (NHPs), without adjuvant systemic anti-inflammatory prophylaxis. For the first time, we describe the early kinetics of retinal detachment at 2, 4, and 7 days after subretinal injection using multimodal imaging in 5 NHPs. We revealed prolonged reattachment times in LV-RPE65-injected eyes compared to vehicle-injected eyes. Low- (n = 2) and high-dose (n = 2) LV-RPE65-injected eyes presented a reduction of the outer nuclear and photoreceptor outer segment layer thickness in the macula, that was more pronounced than in vehicle-injected eyes (n = 4). All LV-RPE65-injected eyes showed an initial perivascular reaction that resolved spontaneously within 14 days. Despite foveal structural changes, full-field electroretinography indicated that the overall retinal function was preserved over time and immunohistochemistry identified no difference in glial, microglial, or leucocyte ocular activation between low-dose, high-dose, and vehicle-injected eyes. Moreover, LV-RPE65-injected animals did not show signs of vector shedding or extraocular targeting, confirming the safe ocular restriction of the vector. Our results evidence a limited ocular tolerance to LV-RPE65 after subretinal injection without adjuvant anti-inflammatory prophylaxis, with complications linked to this route of administration necessitating to block this transient inflammatory event.
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23
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Gupta PR, Huckfeldt RM. Gene therapy for inherited retinal degenerations: initial successes and future challenges. J Neural Eng 2017; 14:051002. [DOI: 10.1088/1741-2552/aa7a27] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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24
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Mowat FM, Occelli LM, Bartoe JT, Gervais KJ, Bruewer AR, Querubin J, Dinculescu A, Boye SL, Hauswirth WW, Petersen-Jones SM. Gene Therapy in a Large Animal Model of PDE6A-Retinitis Pigmentosa. Front Neurosci 2017; 11:342. [PMID: 28676737 PMCID: PMC5476745 DOI: 10.3389/fnins.2017.00342] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 06/01/2017] [Indexed: 12/13/2022] Open
Abstract
Despite mutations in the rod phosphodiesterase 6-alpha (PDE6A) gene being well-recognized as a cause of human retinitis pigmentosa, no definitive treatments have been developed to treat this blinding disease. We performed a trial of retinal gene augmentation in the Pde6a mutant dog using Pde6a delivery by capsid-mutant adeno-associated virus serotype 8, previously shown to have a rapid onset of transgene expression in the canine retina. Subretinal injections were performed in 10 dogs at 29–44 days of age, and electroretinography and vision testing were performed to assess functional outcome. Retinal structure was assessed using color fundus photography, spectral domain optical coherence tomography, and histology. Immunohistochemistry was performed to examine transgene expression and expression of other retinal genes. Treatment resulted in improvement in dim light vision and evidence of rod function on electroretinographic examination. Photoreceptor layer thickness in the treated area was preserved compared with the contralateral control vector treated or uninjected eye. Improved rod and cone photoreceptor survival, rhodopsin localization, cyclic GMP levels and bipolar cell dendrite distribution was observed in treated areas. Some adverse effects including foci of retinal separation, foci of retinal degeneration and rosette formation were identified in both AAV-Pde6a and control vector injected regions. This is the first description of successful gene augmentation for Pde6a retinitis pigmentosa in a large animal model. Further studies will be necessary to optimize visual outcomes and minimize complications before translation to human studies.
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Affiliation(s)
- Freya M Mowat
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States.,Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State UniversityRaleigh, NC, United States
| | - Laurence M Occelli
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States
| | - Joshua T Bartoe
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States
| | - Kristen J Gervais
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States
| | - Ashlee R Bruewer
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States
| | - Janice Querubin
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States
| | - Astra Dinculescu
- Department of Ophthalmology, University of Florida College of MedicineGainesville, FL, United States
| | - Sanford L Boye
- Department of Ophthalmology, University of Florida College of MedicineGainesville, FL, United States
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida College of MedicineGainesville, FL, United States
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State UniversityEast Lansing, MI, United States
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25
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Georgiadis A, Duran Y, Ribeiro J, Abelleira-Hervas L, Robbie SJ, Sünkel-Laing B, Fourali S, Gonzalez-Cordero A, Cristante E, Michaelides M, Bainbridge JWB, Smith AJ, Ali RR. Development of an optimized AAV2/5 gene therapy vector for Leber congenital amaurosis owing to defects in RPE65. Gene Ther 2016; 23:857-862. [PMID: 27653967 PMCID: PMC5143366 DOI: 10.1038/gt.2016.66] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/18/2016] [Accepted: 08/26/2016] [Indexed: 12/02/2022]
Abstract
Leber congenital amaurosis is a group of inherited retinal dystrophies that cause severe sight impairment in childhood; RPE65-deficiency causes impaired rod photoreceptor function from birth and progressive impairment of cone photoreceptor function associated with retinal degeneration. In animal models of RPE65 deficiency, subretinal injection of recombinant adeno-associated virus (AAV) 2/2 vectors carrying RPE65 cDNA improves rod photoreceptor function, and intervention at an early stage of disease provides sustained benefit by protecting cone photoreceptors against retinal degeneration. In affected humans, administration of these vectors has resulted to date in relatively modest improvements in photoreceptor function, even when retinal degeneration is comparatively mild, and the duration of benefit is limited by progressive retinal degeneration. We conclude that the demand for RPE65 in humans is not fully met by current vectors, and predict that a more powerful vector will provide more durable benefit. With this aim we have modified the original AAV2/2 vector to generate AAV2/5-OPTIRPE65. The new configuration consists of an AAV vector serotype 5 carrying an optimized hRPE65 promoter and a codon-optimized hRPE65 gene. In mice, AAV2/5-OPTIRPE65 is at least 300-fold more potent than our original AAV2/2 vector.
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Affiliation(s)
- A Georgiadis
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Y Duran
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - J Ribeiro
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - L Abelleira-Hervas
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - S J Robbie
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - B Sünkel-Laing
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - S Fourali
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - A Gonzalez-Cordero
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - E Cristante
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - M Michaelides
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital, London EC1V 2PD, UK
| | - J W B Bainbridge
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital, London EC1V 2PD, UK
| | - A J Smith
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - R R Ali
- Department of Genetics, UCL Institute of Ophthalmology, London EC1V 9EL, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital, London EC1V 2PD, UK
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26
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Abstract
Over the last few years, huge progress has been made with regard to the understanding of molecular mechanisms underlying the pathogenesis of neurodegenerative diseases of the eye. Such knowledge has led to the development of gene therapy approaches to treat these devastating disorders. Challenges regarding the efficacy and efficiency of therapeutic gene delivery have driven the development of novel therapeutic approaches, which continue to evolve the field of ocular gene therapy. In this review article, we will discuss the evolution of preclinical and clinical strategies that have improved gene therapy in the eye, showing that treatment of vision loss has a bright future.
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Affiliation(s)
- Lolita Petit
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Hemant Khanna
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts.,2 Department of Neurobiology, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Claudio Punzo
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts.,2 Department of Neurobiology, University of Massachusetts Medical School , Worcester, Massachusetts
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27
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Downs LM, Webster AR, Moore AT, Michaelides M, Ali RR, Hardcastle AJ, Mellersh CS. Investigation of SLA4A3 as a candidate gene for human retinal disease. J Negat Results Biomed 2016; 15:11. [PMID: 27211793 PMCID: PMC4876561 DOI: 10.1186/s12952-016-0054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 04/14/2016] [Indexed: 11/10/2022] Open
Abstract
SLC4A3 has been shown to cause retinal degeneration in a genetically engineered knockout mouse, and in a naturally occurring form of canine progressive retinal atrophy considered to be the equivalent of retinitis pigmentosa in humans (RP). This study was undertaken to investigate if SLC4A3 coding variants were implicated in human retinal degeneration. SLC4A3 exons were amplified and sequenced in 200 patients with autosomal recessive retinal degeneration who had no known molecular diagnosis for their condition, which included 197 unrelated individuals with suspected RP and three individuals with other forms of retinal disease. Three rare variants were identified that were predicted to be potentially pathogenic, however each variant was heterozygous in a single patient and therefore not considered disease-causing in isolation. Of these three variants, SNP-3 was the rarest, with an allele frequency of 7.06 x 10(-5) (>46,000 exomes from the ExAC database). In conclusion, no compound heterozygous or homozygous potentially pathogenic variants were identified that would account for recessive RP or retinal degeneration in this cohort, however the possibility remains that the rare variants identified could be acting with as yet undiscovered mutations in introns or regulatory regions. SLC4A3 remains an excellent candidate gene for human retinal degeneration, and with the advent of whole exome and whole genome sequencing of cohorts of molecularly unsolved patients with syndromic and non-syndromic forms of retinal degeneration, SLC4A3 may yet be implicated in human disease.
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Affiliation(s)
- Louise M Downs
- Kennel Club Genetics Centre, Animal Health Trust, Newmarket, UK. .,Present Address: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, USA.
| | - Andrew R Webster
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, City Road, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, City Road, London, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, City Road, London, UK
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28
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Boyd RF, Sledge DG, Boye SL, Boye SE, Hauswirth WW, Komáromy AM, Petersen-Jones SM, Bartoe JT. Photoreceptor-targeted gene delivery using intravitreally administered AAV vectors in dogs. Gene Ther 2016; 23:223-30. [PMID: 26467396 PMCID: PMC4840844 DOI: 10.1038/gt.2015.96] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/03/2015] [Accepted: 08/24/2015] [Indexed: 12/11/2022]
Abstract
Delivery of therapeutic transgenes to retinal photoreceptors using adeno-associated virus (AAV) vectors has traditionally required subretinal injection. Recently, photoreceptor transduction efficiency following intravitreal injection (IVT) has improved in rodent models through use of capsid-mutant AAV vectors; but remains limited in large animal models. Thickness of the inner limiting membrane (ILM) in large animals is thought to impair retinal penetration by AAV. Our study compared two newly developed AAV vectors containing multiple capsid amino acid substitutions following IVT in dogs. The ability of two promoter constructs to restrict reporter transgene expression to photoreceptors was also evaluated. AAV vectors containing the interphotoreceptor-binding protein (IRBP) promoter drove expression exclusively in rod and cone photoreceptors, with transduction efficiencies of ~4% of cones and 2% of rods. Notably, in the central region containing the cone-rich visual streak, 15.6% of cones were transduced. Significant regional variation existed, with lower transduction efficiencies in the temporal regions of all eyes. This variation did not correlate with ILM thickness. Vectors carrying a cone-specific promoter failed to transduce a quantifiable percentage of cone photoreceptors. The newly developed AAV vectors containing the IRBP promoter were capable of producing photoreceptor-specific transgene expression following IVT in the dog.
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Affiliation(s)
- RF Boyd
- Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - DG Sledge
- Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA
| | - SL Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - SE Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - WW Hauswirth
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - AM Komáromy
- Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - SM Petersen-Jones
- Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - JT Bartoe
- Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
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29
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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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30
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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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31
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Bainbridge JWB, Mehat MS, Sundaram V, Robbie SJ, Barker SE, Ripamonti C, Georgiadis A, Mowat FM, Beattie SG, Gardner PJ, Feathers KL, Luong VA, Yzer S, Balaggan K, Viswanathan A, de Ravel TJL, Casteels I, Holder GE, Tyler N, Fitzke FW, Weleber RG, Nardini M, Moore AT, Thompson DA, Petersen-Jones SM, Michaelides M, van den Born LI, Stockman A, Smith AJ, Rubin G, Ali RR. Long-term effect of gene therapy on Leber's congenital amaurosis. N Engl J Med 2015; 372:1887-97. [PMID: 25938638 PMCID: PMC4497809 DOI: 10.1056/nejmoa1414221] [Citation(s) in RCA: 528] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Mutations in RPE65 cause Leber's congenital amaurosis, a progressive retinal degenerative disease that severely impairs sight in children. Gene therapy can result in modest improvements in night vision, but knowledge of its efficacy in humans is limited. METHODS We performed a phase 1-2 open-label trial involving 12 participants to evaluate the safety and efficacy of gene therapy with a recombinant adeno-associated virus 2/2 (rAAV2/2) vector carrying the RPE65 complementary DNA, and measured visual function over the course of 3 years. Four participants were administered a lower dose of the vector, and 8 were administered a higher dose. In a parallel study in dogs, we investigated the relationship among vector dose, visual function, and electroretinography (ERG) findings. RESULTS Improvements in retinal sensitivity were evident, to varying extents, in six participants for up to 3 years, peaking at 6 to 12 months after treatment and then declining. No associated improvement in retinal function was detected by means of ERG. Three participants had intraocular inflammation, and two had clinically significant deterioration of visual acuity. The reduction in central retinal thickness varied among participants. In dogs, RPE65 gene therapy with the same vector at lower doses improved vision-guided behavior, but only higher doses resulted in improvements in retinal function that were detectable with the use of ERG. CONCLUSIONS Gene therapy with rAAV2/2 RPE65 vector improved retinal sensitivity, albeit modestly and temporarily. Comparison with the results obtained in the dog model indicates that there is a species difference in the amount of RPE65 required to drive the visual cycle and that the demand for RPE65 in affected persons was not met to the extent required for a durable, robust effect. (Funded by the National Institute for Health Research and others; ClinicalTrials.gov number, NCT00643747.).
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Affiliation(s)
- James W B Bainbridge
- From the UCL (University College London) Institute of Ophthalmology (J.W.B.B., M.S.M., V.S., S.J.R., S.E.B., C.R., A.G., F.M.M., S.G.B., P.J.G., V.A.L., K.B., A.V., G.E.H., F.W.F., M.N., A.T.M., M.M., A.S., A.J.S., G.R., R.R.A.) and the Department of Civil, Environmental, and Geomatic Engineering (N.T.), UCL, and Moorfields Eye Hospital (J.W.B.B., M.S.M., V.S., S.J.R., A.G., K.B., G.H., A.M., M.M.), London, and the Department of Psychology, Durham University, Durham (M.N.) - all in the United Kingdom; the College of Veterinary Medicine, Michigan State University, East Lansing (F.M.M., S.M.P.-J.), and the Kellogg Eye Center, University of Michigan Medical School, Ann Arbor (K.L.F., D.A.T., R.R.A.); the Center for Human Genetics, KU Leuven (T.J.L.R.), and the Department of Ophthalmology, UZ Leuven, Campus Sint-Rafaël (I.C.) - both in Leuven, Belgium; Rotterdam Eye Hospital, Rotterdam, the Netherlands (S.Y., L.I.B.); and the Oregon Retinal Degeneration Center, Ophthalmic Genetics Service, Casey Eye Institute, Oregon Health and Science University, Portland (R.G.W.)
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32
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Han Z, Banworth MJ, Makkia R, Conley SM, Al-Ubaidi MR, Cooper MJ, Naash MI. Genomic DNA nanoparticles rescue rhodopsin-associated retinitis pigmentosa phenotype. FASEB J 2015; 29:2535-44. [PMID: 25713057 DOI: 10.1096/fj.15-270363] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 02/09/2015] [Indexed: 01/10/2023]
Abstract
Mutations in the rhodopsin gene cause retinal degeneration and clinical phenotypes including retinitis pigmentosa (RP) and congenital stationary night blindness. Effective gene therapies have been difficult to develop, however, because generating precise levels of rhodopsin expression is critical; overexpression causes toxicity, and underexpression would result in incomplete rescue. Current gene delivery strategies routinely use cDNA-based vectors for gene targeting; however, inclusion of noncoding components of genomic DNA (gDNA) such as introns may help promote more endogenous regulation of gene expression. Here we test the hypothesis that inclusion of genomic sequences from the rhodopsin gene can improve the efficacy of rhodopsin gene therapy in the rhodopsin knockout (RKO) mouse model of RP. We utilize our compacted DNA nanoparticles (NPs), which have the ability to transfer larger and more complex genetic constructs, to deliver murine rhodopsin cDNA or gDNA. We show functional and structural improvements in RKO eyes for up to 8 months after NP-mediated gDNA but not cDNA delivery. Importantly, in addition to improvements in rod function, we observe significant preservation of cone function at time points when cones in the RKO model are degenerated. These results suggest that inclusion of native expression elements, such as introns, can significantly enhance gene expression and therapeutic efficacy and may become an essential option in the array of available gene delivery tools.
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Affiliation(s)
- Zongchao Han
- *Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; and Copernicus Therapeutics, Incorporated, Cleveland, Ohio, USA
| | - Marcellus J Banworth
- *Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; and Copernicus Therapeutics, Incorporated, Cleveland, Ohio, USA
| | - Rasha Makkia
- *Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; and Copernicus Therapeutics, Incorporated, Cleveland, Ohio, USA
| | - Shannon M Conley
- *Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; and Copernicus Therapeutics, Incorporated, Cleveland, Ohio, USA
| | - Muayyad R Al-Ubaidi
- *Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; and Copernicus Therapeutics, Incorporated, Cleveland, Ohio, USA
| | - Mark J Cooper
- *Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; and Copernicus Therapeutics, Incorporated, Cleveland, Ohio, USA
| | - Muna I Naash
- *Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; and Copernicus Therapeutics, Incorporated, Cleveland, Ohio, USA
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33
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Petersen-Jones SM, Komáromy AM. Dog models for blinding inherited retinal dystrophies. HUM GENE THER CL DEV 2015; 26:15-26. [PMID: 25671556 DOI: 10.1089/humc.2014.155] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Spontaneous canine models exist for several inherited retinal dystrophies. This review will summarize the models and indicate where they have been used in translational gene therapy trials. The RPE65 gene therapy trials to treat childhood blindness are a good example of how studies in dogs have contributed to therapy development. Outcomes in human clinical trials are compared and contrasted with the result of the preclinical dog trials.
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Affiliation(s)
- Simon M Petersen-Jones
- 1 Department of Small Animal Clinical Sciences, Michigan State University , East Lansing, MI 48824
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34
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Petersen-Jones S, Komaromy AM. Dog Models for Blinding Inherited Retinal Degenerations. HUM GENE THER CL DEV 2014. [DOI: 10.1089/hum.2014.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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35
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Trapani I, Puppo A, Auricchio A. Vector platforms for gene therapy of inherited retinopathies. Prog Retin Eye Res 2014; 43:108-28. [PMID: 25124745 PMCID: PMC4241499 DOI: 10.1016/j.preteyeres.2014.08.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/26/2014] [Accepted: 08/02/2014] [Indexed: 12/20/2022]
Abstract
Inherited retinopathies (IR) are common untreatable blinding conditions. Most of them are inherited as monogenic disorders, due to mutations in genes expressed in retinal photoreceptors (PR) and in retinal pigment epithelium (RPE). The retina's compatibility with gene transfer has made transduction of different retinal cell layers in small and large animal models via viral and non-viral vectors possible. The ongoing identification of novel viruses as well as modifications of existing ones based either on rational design or directed evolution have generated vector variants with improved transduction properties. Dozens of promising proofs of concept have been obtained in IR animal models with both viral and non-viral vectors, and some of them have been relayed to clinical trials. To date, recombinant vectors based on the adeno-associated virus (AAV) represent the most promising tool for retinal gene therapy, given their ability to efficiently deliver therapeutic genes to both PR and RPE and their excellent safety and efficacy profiles in humans. However, AAVs' limited cargo capacity has prevented application of the viral vector to treatments requiring transfer of genes with a coding sequence larger than 5 kb. Vectors with larger capacity, i.e. nanoparticles, adenoviral and lentiviral vectors are being exploited for gene transfer to the retina in animal models and, more recently, in humans. This review focuses on the available platforms for retinal gene therapy to fight inherited blindness, highlights their main strengths and examines the efforts to overcome some of their limitations.
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Affiliation(s)
- Ivana Trapani
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Agostina Puppo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy; Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy.
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Sahel JA, Marazova K, Audo I. Clinical characteristics and current therapies for inherited retinal degenerations. Cold Spring Harb Perspect Med 2014; 5:a017111. [PMID: 25324231 DOI: 10.1101/cshperspect.a017111] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Inherited retinal degenerations (IRDs) encompass a large group of clinically and genetically heterogeneous diseases that affect approximately 1 in 3000 people (>2 million people worldwide) (Bessant DA, Ali RR, Bhattacharya SS. 2001. Molecular genetics and prospects for therapy of the inherited retinal dystrophies. Curr Opin Genet Dev 11: 307-316.). IRDs may be inherited as Mendelian traits or through mitochondrial DNA, and may affect the entire retina (e.g., rod-cone dystrophy, also known as retinitis pigmentosa, cone dystrophy, cone-rod dystrophy, choroideremia, Usher syndrome, and Bardet-Bidel syndrome) or be restricted to the macula (e.g., Stargardt disease, Best disease, and Sorsby fundus dystrophy), ultimately leading to blindness. IRDs are a major cause of severe vision loss, with profound impact on patients and society. Although IRDs remain untreatable today, significant progress toward therapeutic strategies for IRDs has marked the past two decades. This progress has been based on better understanding of the pathophysiological pathways of these diseases and on technological advances.
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Affiliation(s)
- José-Alain Sahel
- Institut de la Vision, Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Paris, F-75012, France INSERM, U968, Paris, F-75012, France CNRS, UMR 7210, Paris, F-75012, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU ViewMaintain, INSERM-DHOS CIC 1423, Paris, F-75012, France Fondation Ophtalmologique Adolphe de Rothschild, Paris, F-75019, France Académie des Sciences-Institut de France, Paris, F-75006, France Institute of Ophthalmology-University College London, London EC1V 9EL, United Kingdom
| | - Katia Marazova
- Institut de la Vision, Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Paris, F-75012, France INSERM, U968, Paris, F-75012, France CNRS, UMR 7210, Paris, F-75012, France
| | - Isabelle Audo
- Institut de la Vision, Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Paris, F-75012, France INSERM, U968, Paris, F-75012, France CNRS, UMR 7210, Paris, F-75012, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU ViewMaintain, INSERM-DHOS CIC 1423, Paris, F-75012, France Institute of Ophthalmology-University College London, London EC1V 9EL, United Kingdom
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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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Annear MJ, Mowat FM, Bartoe JT, Querubin J, Azam SA, Basche M, Curran PG, Smith AJ, Bainbridge JWB, Ali RR, Petersen-Jones SM. Successful gene therapy in older Rpe65-deficient dogs following subretinal injection of an adeno-associated vector expressing RPE65. Hum Gene Ther 2014; 24:883-93. [PMID: 24028205 DOI: 10.1089/hum.2013.146] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Young Rpe65-deficient dogs have been used as a model for human RPE65 Leber congenital amaurosis (RPE65-LCA) in proof-of-concept trials of recombinant adeno-associated virus (rAAV) gene therapy. However, there are relatively few reports of the outcome of rAAV gene therapy in Rpe65-deficient dogs older than 2 years of age. The purpose of this study was to investigate the success of this therapy in older Rpe65-deficient dogs. Thirteen eyes were treated in dogs between 2 and 6 years old. An rAAV2 vector expressing the human RPE65 cDNA driven by the human RPE65 promoter was delivered by subretinal injection. Twelve of the 13 eyes had improved retinal function as assessed by electroretinography, and all showed improvement in vision at low lighting intensities. Histologic examination of five of the eyes was performed but found no correlation between electroretinogram (ERG) rescue and numbers of remaining photoreceptors. We conclude that functional rescue is still possible in older dogs and that the use of older Rpe65-deficient dogs, rather than young Rpe65-deficient dogs that have very little loss of photoreceptors, more accurately models the situation when treating human RPE65-LCA patients.
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Affiliation(s)
- Matthew J Annear
- 1 Department of Small Animal Clinical Sciences, Michigan State University , East Lansing, MI 48824
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Willett K, Bennett J. Immunology of AAV-Mediated Gene Transfer in the Eye. Front Immunol 2013; 4:261. [PMID: 24009613 PMCID: PMC3757345 DOI: 10.3389/fimmu.2013.00261] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 08/16/2013] [Indexed: 12/20/2022] Open
Abstract
The eye has been at the forefront of translational gene therapy largely owing to suitable disease targets, anatomic accessibility, and well-studied immunologic privilege. These advantages have fostered research culminating in several clinical trials and adeno-associated virus (AAV) has emerged as the vector of choice for many ocular therapies. Pre-clinical and clinical investigations have assessed the humoral and cellular immune responses to a variety of naturally occurring and engineered AAV serotypes as well as their delivered transgenes and these data have been correlated to potential clinical sequelae. Encouragingly, AAV appears safe and effective with clinical follow-up surpassing 5 years in some studies. As disease targets continue to expand for AAV in the eye, thorough and deliberate assessment of immunologic safety is critical. With careful study, the development of these technologies should concurrently inform the biology of the ocular immune response.
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Affiliation(s)
- Keirnan Willett
- Department of Ophthalmology, Scheie Eye Institute, F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania , Philadelphia, PA , USA
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Winkler PA, Ekenstedt KJ, Occelli LM, Frattaroli AV, Bartoe JT, Venta PJ, Petersen-Jones SM. A large animal model for CNGB1 autosomal recessive retinitis pigmentosa. PLoS One 2013; 8:e72229. [PMID: 23977260 PMCID: PMC3747135 DOI: 10.1371/journal.pone.0072229] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 07/08/2013] [Indexed: 11/25/2022] Open
Abstract
Retinal dystrophies in dogs are invaluable models of human disease. Progressive retinal atrophy (PRA) is the canine equivalent of retinitis pigmentosa (RP). Similar to RP, PRA is a genetically heterogenous condition. We investigated PRA in the Papillon breed of dog using homozygosity mapping and haplotype construction of single nucleotide polymorphisms within a small family group to identify potential positional candidate genes. Based on the phenotypic similarities between the PRA-affected Papillons, mouse models and human patients, CNGB1 was selected as the most promising positional candidate gene. CNGB1 was sequenced and a complex mutation consisting of the combination of a one basepair deletion and a 6 basepair insertion was identified in exon 26 (c.2387delA;2389_2390insAGCTAC) leading to a frameshift and premature stop codon. Immunohistochemistry (IHC) of pre-degenerate retinal sections from a young affected dog showed absence of labeling using a C-terminal CNGB1 antibody. Whereas an antibody directed against the N-terminus of the protein, which also recognizes the glutamic acid rich proteins arising from alternative splicing of the CNGB1 transcript (upstream of the premature stop codon), labeled rod outer segments. CNGB1 combines with CNGA1 to form the rod cyclic nucleotide gated channel and previous studies have shown the requirement of CNGB1 for normal targeting of CNGA1 to the rod outer segment. In keeping with these previous observations, IHC showed a lack of detectable CNGA1 protein in the rod outer segments of the affected dog. A population study did not identify the CNGB1 mutation in PRA-affected dogs in other breeds and documented that the CNGB1 mutation accounts for ∼70% of cases of Papillon PRA in our PRA-affected canine DNA bank. CNGB1 mutations are one cause of autosomal recessive RP making the CNGB1 mutant dog a valuable large animal model of the condition.
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Affiliation(s)
- Paige A. Winkler
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, United States of America
- Genetics Program, Michigan State University, East Lansing, Michigan, United States of America
| | - Kari J. Ekenstedt
- Department of Animal and Food Sciences, University of Wisconsin-River Falls, River Falls, Wisconsin, United States of America
| | - Laurence M. Occelli
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Anton V. Frattaroli
- Health Information Technology, Michigan State University, East Lansing, Michigan, United States of America
| | - Joshua T. Bartoe
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Patrick J. Venta
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, United States of America
- Genetics Program, Michigan State University, East Lansing, Michigan, United States of America
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Simon M. Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, United States of America
- Genetics Program, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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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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Human retinal gene therapy for Leber congenital amaurosis shows advancing retinal degeneration despite enduring visual improvement. Proc Natl Acad Sci U S A 2013; 110:E517-25. [PMID: 23341635 DOI: 10.1073/pnas.1218933110] [Citation(s) in RCA: 328] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Leber congenital amaurosis (LCA) associated with retinal pigment epithelium-specific protein 65 kDa (RPE65) mutations is a severe hereditary blindness resulting from both dysfunction and degeneration of photoreceptors. Clinical trials with gene augmentation therapy have shown partial reversal of the dysfunction, but the effects on the degeneration are not known. We evaluated the consequences of gene therapy on retinal degeneration in patients with RPE65-LCA and its canine model. In untreated RPE65-LCA patients, there was dysfunction and degeneration of photoreceptors, even at the earliest ages. Examined serially over years, the outer photoreceptor nuclear layer showed progressive thinning. Treated RPE65-LCA showed substantial visual improvement in the short term and no detectable decline from this new level over the long term. However, retinal degeneration continued to progress unabated. In RPE65-mutant dogs, the first one-quarter of their lifespan showed only dysfunction, and there was normal outer photoreceptor nuclear layer thickness retina-wide. Dogs treated during the earlier dysfunction-only stage showed improved visual function and dramatic protection of treated photoreceptors from degeneration when measured 5-11 y later. Dogs treated later during the combined dysfunction and degeneration stage also showed visual function improvement, but photoreceptor loss continued unabated, the same as in human RPE65-LCA. The results suggest that, in RPE65 disease treatment, protection from visual function deterioration cannot be assumed to imply protection from degeneration. The effects of gene augmentation therapy are complex and suggest a need for a combinatorial strategy in RPE65-LCA to not only improve function in the short term but also slow retinal degeneration in the long term.
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43
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Petersen-Jones SM. Drug and gene therapy of hereditary retinal disease in dog and cat models. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.ddmod.2014.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Annear MJ, Gornik KR, Venturi FL, Hauptman JG, Bartoe JT, Petersen-Jones SM. Reproducibility of an objective four-choice canine vision testing technique that assesses vision at differing light intensities. Vet Ophthalmol 2012; 16:324-8. [PMID: 23121436 DOI: 10.1111/j.1463-5224.2012.01076.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The increasing importance of canine retinal dystrophy models means accurate vision testing is needed. This study was performed to evaluate a four-choice vision testing technique for any difference in outcome measures with repeated evaluations of the same dogs. ANIMALS STUDIED Four 11-month-old RPE65-deficient dogs. PROCEDURES Vision was evaluated using a previously described four-choice vision testing device. Four evaluations were performed at 2-week intervals. Vision was assessed at six different white light intensities (bright through dim), and each eye was evaluated separately. The ability to select the one of the four exit tunnels that was open at the far end was assessed ('choice of exit') and recorded as correct or incorrect first tunnel choice. 'Time to exit' the device was also recorded. Both outcomes were analyzed for significance using anova. We hypothesized that performance would improve with repeated testing (more correct choices and more rapid time to exit). RESULTS 'Choice of exit' did not vary significantly between each evaluation (P = 0.12), in contrast 'time to exit' increased significantly (P = 0.012), and showed greater variability in dim light conditions. CONCLUSIONS We found no evidence to support the hypothesis that either measure of outcome worsened with repeated testing; in fact, the 'time to exit' outcome worsened rather than improved. The 'choice of exit' gave consistent results between trials. These outcome data indicate the importance of including a choice-based assessment of vision in addition to measurement of device transit time.
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Affiliation(s)
- Matthew J Annear
- Veterinary Clinical Sciences, The Ohio State University, 601 Vernon L. Tharp St, Columbus, OH 43210, USA.
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Boye SE, Alexander JJ, Boye SL, Witherspoon CD, Sandefer KJ, Conlon TJ, Erger K, Sun J, Ryals R, Chiodo VA, Clark ME, Girkin CA, Hauswirth WW, Gamlin PD. The human rhodopsin kinase promoter in an AAV5 vector confers rod- and cone-specific expression in the primate retina. Hum Gene Ther 2012; 23:1101-15. [PMID: 22845794 DOI: 10.1089/hum.2012.125] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Adeno-associated virus (AAV) has proven an effective gene delivery vehicle for the treatment of retinal disease. Ongoing clinical trials using a serotype 2 AAV vector to express RPE65 in the retinal pigment epithelium have proven safe and effective. While many proof-of-concept studies in animal models of retinal disease have suggested that gene transfer to the neural retina will also be effective, a photoreceptor-targeting AAV vector has yet to be used in the clinic, principally because a vector that efficiently but exclusively targets all primate photoreceptors has yet to be demonstrated. Here, we evaluate a serotype 5 AAV vector containing the human rhodopsin kinase (hGRK1) promoter for its ability to target transgene expression to rod and cone photoreceptors when delivered subretinally in a nonhuman primate (NHP). In vivo fluorescent fundus imaging confirmed that AAV5-hGRK1-mediated green fluorescent protein (GFP) expression was restricted to the injection blebs of treated eyes. Optical coherence tomography (OCT) revealed a lack of gross pathology after injection. Neutralizing antibodies against AAV5 were undetectable in post-injection serum samples from subjects receiving uncomplicated subretinal injections (i.e., no hemorrhage). Immunohistochemistry of retinal sections confirmed hGRK1 was active in, and specific for, both rods and cones of NHP retina. Biodistribution studies revealed minimal spread of vector genomes to peripheral tissues. These results suggest that AAV5-hGRK1 is a safe and effective AAV serotype/promoter combination for targeting therapeutic transgene expression protein to rods and cones in a clinical setting.
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Affiliation(s)
- Shannon E Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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Mowat FM, Breuwer AR, Bartoe JT, Annear MJ, Zhang Z, Smith AJ, Bainbridge JWB, Petersen-Jones SM, Ali RR. RPE65 gene therapy slows cone loss in Rpe65-deficient dogs. Gene Ther 2012; 20:545-55. [PMID: 22951453 DOI: 10.1038/gt.2012.63] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent clinical trials of retinal pigment epithelium gene (RPE65) supplementation therapy in Leber congenital amaurosis type 2 patients have demonstrated improvements in rod and cone function, but it may be some years before the effects of therapy on photoreceptor survival become apparent. The Rpe65-deficient dog is a very useful pre-clinical model in which to test efficacy of therapies, because the dog has a retina with a high degree of similarity to that of humans. In this study, we evaluated the effect of RPE65 gene therapy on photoreceptor survival in order to predict the potential benefit and limitations of therapy in patients. We examined the retinas of Rpe65-deficient dogs after RPE65 gene therapy to evaluate the preservation of rods and cone photoreceptor subtypes. We found that gene therapy preserves both rods and cones. While the moderate loss of rods in the Rpe65-deficient dog retina is slowed by gene therapy, S-cones are lost extensively and gene therapy can prevent that loss, although only within the treated area. Although LM-cones are not lost extensively, cone opsin mislocalization indicates that they are stressed, and this can be partially reversed by gene therapy. Our results suggest that gene therapy may be able to slow cone degeneration in patients if intervention is sufficiently early and also that it is probably important to treat the macula in order to preserve central function.
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Affiliation(s)
- F M Mowat
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
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Abstract
Clinical trials are currently underway using gene therapy to treat retinal disease such as Leber congenital amaurosis (LCA). Viral vectors that have been utilized to target retinal cells include adenoviruses, lentiviruses, and recombinant adeno-associated viruses (rAAV). Of the three classes, rAAV vectors show the greatest promise for retinal gene therapy. Recent developments in virus technology such as the development of hybrid and capsid mutant rAAV vectors mean that specific retinal cells can be targeted and faster stronger transgene expression is now possible compared to that achieved with the first generation of vectors. Gene therapy trials in dogs have been very important in the development of therapy for RPE65 LCA which is currently in phase I/II clinical trials in humans. Recent successes in using gene therapy to treat canine achromatopsia, X-linked progressive retinal atrophy (PRA) and the more severe rapid degenerations such as rod-cone dysplasia type 3 may lead also to the translation to human clinical trials. Dogs have played and continue to play an important role as animal models for proof-of-concept studies of retinal gene therapy. As modifications and improvements in gene therapy protocols are made from experience gathered from human clinical trials perhaps gene therapy for the treatment of canine clinical patients will become available to veterinary ophthalmologists.
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Affiliation(s)
- Simon M Petersen-Jones
- Veterinary Medical Center, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI 48824, USA.
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Shao J, Tian L, Lei B, Wei L, Yang Y, Kijlstra A, Yang P. AAV2-mediated subretinal gene transfer of mIL-27p28 attenuates experimental autoimmune uveoretinitis in mice. PLoS One 2012; 7:e37773. [PMID: 22629453 PMCID: PMC3358269 DOI: 10.1371/journal.pone.0037773] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 04/27/2012] [Indexed: 11/28/2022] Open
Abstract
Background Advances in gene transfer techniques have provided long-term, safe and stable transduction of retinal cells following subretinal injection with adeno-associated viral (AAV) vectors. In this study we investigated whether subretinal injection of AAV2-murine IL-27p28 vector was effective in inhibiting experimental autoimmune uveoretinitis (EAU) induced in B10RIII mice. Methodology/Principal Findings An AAV2 vector encoding the murine IL-27p28 gene (rAAV2-CMV-mIL-27p28) was prepared and subretinally injected into B10RIII mice (4.35×108 vector genome (v.g.)). AAV2 vector mediating green fluorescent protein (rAAV2-CMV-GFP) served as a control (5×108 v.g.). The concentration of mIL-27p28 in homogenized eyes and serum was assayed by enzyme linked immunosorbent assay (ELISA) after subretinal injection. Human IRBP161–180 peptide and Complete Freund’s Adjuvant were injected into mice receiving either the rAAV2-CMV-mIL-27p28 or rAAV2-CMV-GFP vector. EAU was evaluated clinically and pathologically. The level of IL-17 and IL-10 in homogenized eyes was measured on day 12 and day 21 following immunization. Delayed type hypersensitivity (DTH) and IRBP161–180–specific proliferation of lymphocytes from the spleen and lymph nodes were assayed to examine the influence of the subretinal delivery of rAAV2-CMV-mIL-27p28 on the systemic immune response. IL-27p28 was detectable by ELISA within the eyes from two weeks following subretinal injection of the rAAV2-CMV-mIL-27p28 vector and showed a sustained high expression from day 14 to 9 months with a highest expression at 5 months. Subretinal injection of the vector significantly attenuated the severity of EAU disease clinically and pathologically in association with a significantly decreased IL-17 expression and an increased IL-10 expression. The IL-27p28 vector did not affect the systemic immune response, as determined by DTH and IRBP161–180–specific lymphocyte proliferation. Conclusions/Significance A high and stable expression of IL-27p28 was observed for at least 9 months following subretinal delivery of rAAV2-CMV-mIL-27p28. The amelioration of EAU disease severity was associated with a decreased IL-17 expression and an increased IL-10 expression.
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Affiliation(s)
- Ju Shao
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Medical University, The First Affiliated Hospital, Chongqing, People’s Republic of China
| | - Lichun Tian
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Medical University, The First Affiliated Hospital, Chongqing, People’s Republic of China
| | - Bo Lei
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Medical University, The First Affiliated Hospital, Chongqing, People’s Republic of China
| | - Lin Wei
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Medical University, The First Affiliated Hospital, Chongqing, People’s Republic of China
| | - Yan Yang
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Medical University, The First Affiliated Hospital, Chongqing, People’s Republic of China
| | - Aize Kijlstra
- Eye Research Institute Maastricht, Department of Ophthalmology, University Hospital Maastricht, Maastricht, The Netherlands
| | - Peizeng Yang
- Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Medical University, The First Affiliated Hospital, Chongqing, People’s Republic of China
- * E-mail:
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49
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Petersen-Jones SM, Annear MJ, Bartoe JT, Mowat FM, Barker SE, Smith AJ, Bainbridge JW, Ali RR. Gene augmentation trials using the Rpe65-deficient dog: contributions towards development and refinement of human clinical trials. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:177-82. [PMID: 22183331 DOI: 10.1007/978-1-4614-0631-0_24] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA.
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50
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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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