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Poli G, Barravecchia I, Demontis GC, Sodi A, Saba A, Rizzo S, Macchia M, Tuccinardi T. Predicting potentially pathogenic effects of hRPE65 missense mutations: a computational strategy based on molecular dynamics simulations. J Enzyme Inhib Med Chem 2022; 37:1765-1772. [PMID: 35726567 PMCID: PMC9225791 DOI: 10.1080/14756366.2022.2090547] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The human retinal pigment epithelium-specific 65-kDa protein (hRPE65) plays a crucial role within the retinoid visual cycle and several mutations affecting either its expression level or its enzymatic function are associated with inherited retinal diseases such as Retinitis Pigmentosa. The gene therapy product voretigene neparvovec (Luxturna) has been recently approved for treating hereditary retinal dystrophies; however, the treatment is currently accessible only to patients presenting confirmed biallelic mutations that severely impair hRPE65 function, and many reported hRPE65 missense mutations lack sufficient evidences for proving their pathogenicity. In this context, we developed a computational approach aimed at evaluating the potential pathogenic effect of hRPE65 missense variants located on the dimerisation domain of the protein. The protocol evaluates how mutations may affect folding and conformation stability of this protein region, potentially helping clinicians to evaluate the eligibility for gene therapy of patients diagnosed with this type of hRPE65 variant of uncertain significance.
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Affiliation(s)
- Giulio Poli
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Ivana Barravecchia
- Department of Pharmacy, University of Pisa, Pisa, Italy.,Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | | | - Andrea Sodi
- Department of Neurosciences, Psychology, Drug Research and Child Health Eye Clinic, University of Florence, AOU Careggi, Florence, Italy
| | - Alessandro Saba
- Department of Surgical Pathology, Molecular Medicine and of the Critical Area, University of Pisa, Pisa, Italy
| | - Stanislao Rizzo
- Ophthalmology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Catholic University Sacro Cuore, Rome, Italy.,Consiglio Nazionale delle Ricerche, Istituto di Neuroscienze, Pisa, Italy
| | - Marco Macchia
- Department of Pharmacy, University of Pisa, Pisa, Italy
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2
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Kiser PD. Retinal pigment epithelium 65 kDa protein (RPE65): An update. Prog Retin Eye Res 2021; 88:101013. [PMID: 34607013 PMCID: PMC8975950 DOI: 10.1016/j.preteyeres.2021.101013] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 12/21/2022]
Abstract
Vertebrate vision critically depends on an 11-cis-retinoid renewal system known as the visual cycle. At the heart of this metabolic pathway is an enzyme known as retinal pigment epithelium 65 kDa protein (RPE65), which catalyzes an unusual, possibly biochemically unique, reaction consisting of a coupled all-trans-retinyl ester hydrolysis and alkene geometric isomerization to produce 11-cis-retinol. Early work on this isomerohydrolase demonstrated its membership to the carotenoid cleavage dioxygenase superfamily and its essentiality for 11-cis-retinal production in the vertebrate retina. Three independent studies published in 2005 established RPE65 as the actual isomerohydrolase instead of a retinoid-binding protein as previously believed. Since the last devoted review of RPE65 enzymology appeared in this journal, major advances have been made in a number of areas including our understanding of the mechanistic details of RPE65 isomerohydrolase activity, its phylogenetic origins, the relationship of its membrane binding affinity to its catalytic activity, its role in visual chromophore production for rods and cones, its modulation by macromolecules and small molecules, and the involvement of RPE65 mutations in the development of retinal diseases. In this article, I will review these areas of progress with the goal of integrating results from the varied experimental approaches to provide a comprehensive picture of RPE65 biochemistry. Key outstanding questions that may prove to be fruitful future research pursuits will also be highlighted.
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Affiliation(s)
- Philip D Kiser
- Research Service, VA Long Beach Healthcare System, Long Beach, CA, 90822, USA; Department of Physiology & Biophysics, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA; Department of Ophthalmology and Center for Translational Vision Research, Gavin Herbert Eye Institute, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA.
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3
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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4
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Zhang X, Girardot PE, Sellers JT, Li Y, Wang J, Chrenek MA, Wu W, Skelton H, Nickerson JM, Pardue MT, Boatright JH. Wheel running exercise protects against retinal degeneration in the I307N rhodopsin mouse model of inducible autosomal dominant retinitis pigmentosa. Mol Vis 2019; 25:462-476. [PMID: 31523123 PMCID: PMC6707757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 08/19/2019] [Indexed: 10/25/2022] Open
Abstract
Purpose We previously reported that modest running exercise protects photoreceptors in mice undergoing light-induced retinal degeneration and in the rd10 mouse model of autosomal recessive retinitis pigmentosa (arRP). We hypothesized that exercise would protect against other types of retinal degeneration, specifically, in autosomal dominant inherited disease. We tested whether voluntary running wheel exercise is protective in a retinal degeneration mouse model of class B1 autosomal dominant RP (adRP). Methods C57BL/6J mice heterozygous for the mutation in I307N rhodopsin (Rho) (also known as RHOTvrm4/+, or Tvrm4) are normal until exposed to brief but bright light, whereupon rod photoreceptor degeneration ensues. I307N Rho mice were given access to free spinning (active) or locked (inactive) running wheels. Five weeks later, half of each cohort was treated with 0.2% atropine eye drops and exposed to white LED light (6,000 lux) for 5 min, then returned to maintenance housing with wheels. At 1 week or 4 weeks after induction, retinal and visual function was assessed with electroretinogram (ERG) and optomotor response (OMR). In vivo retinal morphology was assessed with optical coherence tomography (OCT), and fundus blue autofluorescence assessed using a scanning laser ophthalmoscope. The mice were then euthanized, and the eyes fixed for paraffin sectioning or flatmounting. The paraffin sections were stained with hematoxylin and eosin (H&E) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) to assess retina morphology and apoptosis. Half of the flatmounts were stained for ZO-1 and α-catenin to assess RPE cell structure and stress. (We previously reported that translocation of α-catenin from cell membranes into the cytosol indicates RPE cell stress.) The remaining flatmounts were stained for ZO-1 and Iba-1 to assess the RPE cell size and shape, and inflammatory responses. Results In vivo measures revealed that induction of the I307N Rho degeneration decreased retinal and visual function, decreased the thickness of the retina and photoreceptor layers, and increased the number of blue autofluorescence spots at the level of the photoreceptor-RPE interface. Post-mortem analyses showed that induction caused loss of photoreceptors in the central retinal region, and increased TUNEL labeling in the outer nuclear layer (ONL). The RPE was disrupted 1 week after induction, with changes in cell size and shape accompanied by increased α-catenin translocation and Iba-1 staining. These outcomes were partially but statistically significantly prevented in the exercised mice. The exercised mice that underwent induced I307N Rho degeneration exhibited retinal function and visual function measures that were statistically indistinguishable from that of the uninduced mice, and compared to the unexercised induced mice, had thicker retina and photoreceptor layers, and decreased numbers of subretinal autofluorescent spots. Post-mortem, the retina sections from the exercised mice that had undergone induced I307N Rho degeneration exhibited numbers of photoreceptors that were statistically indistinguishable from those of uninduced mice. Similarly, exercise largely precluded a degeneration-induced increase in TUNEL-positive cells in the ONL. Finally, the RPE of the exercised mice appeared normal, with a regular cell shape and size, and little to no alpha-catenin translocation or Iba-1 immunosignal. Conclusions Voluntary wheel running partially protected against retinal degeneration and inflammation, and RPE disruption in a model of inducible adRP. This is the first report of exercise protection in an adult adRP animal model. It is also the first report of an RPE phenotype in the I307N Rho mouse. These findings add to a growing literature reporting that modest whole-body exercise is protective across a wide range of models of retinal damage and disease, and further highlights the potential for this accessible and inexpensive therapeutic intervention in the ophthalmic clinic.
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Affiliation(s)
- Xian Zhang
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA,Department of Ophthalmology, Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Preston E. Girardot
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA
| | - Jana T. Sellers
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA
| | - Ying Li
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA
| | - Jiaxing Wang
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA
| | - Micah A. Chrenek
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA
| | - Wenfei Wu
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA,The First Affiliated Hospital of Medical School of Xi’an Jiaotong University, Xi’an, Shan’xi, China
| | | | - John M. Nickerson
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA
| | - Machelle T. Pardue
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Administration Health Care System, Decatur, GA,Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA
| | - Jeffrey H. Boatright
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Administration Health Care System, Decatur, GA
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5
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Storchi R, Rodgers J, Gracey M, Martial FP, Wynne J, Ryan S, Twining CJ, Cootes TF, Killick R, Lucas RJ. Measuring vision using innate behaviours in mice with intact and impaired retina function. Sci Rep 2019; 9:10396. [PMID: 31316114 PMCID: PMC6637134 DOI: 10.1038/s41598-019-46836-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 06/26/2019] [Indexed: 01/23/2023] Open
Abstract
Measuring vision in rodents is a critical step for understanding vision, improving models of human disease, and developing therapies. Established behavioural tests for perceptual vision, such as the visual water task, rely on learning. The learning process, while effective for sighted animals, can be laborious and stressful in animals with impaired vision, requiring long periods of training. Current tests that that do not require training are based on sub-conscious, reflex responses (e.g. optokinetic nystagmus) that don't require involvement of visual cortex and higher order thalamic nuclei. A potential alternative for measuring vision relies on using visually guided innate defensive responses, such as escape or freeze, that involve cortical and thalamic circuits. In this study we address this possibility in mice with intact and degenerate retinas. We first develop automatic methods to detect behavioural responses based on high dimensional tracking and changepoint detection of behavioural time series. Using those methods, we show that visually guided innate responses can be elicited using parametisable stimuli, and applied to describing the limits of visual acuity in healthy animals and discriminating degrees of visual dysfunction in mouse models of retinal degeneration.
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Affiliation(s)
- R Storchi
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
| | - J Rodgers
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - M Gracey
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - F P Martial
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - J Wynne
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - S Ryan
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - C J Twining
- School of Computer Science, University of Manchester, Manchester, UK
| | - T F Cootes
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - R Killick
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - R J Lucas
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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6
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Li Y, Furhang R, Ray A, Duncan T, Soucy J, Mahdi R, Chaitankar V, Gieser L, Poliakov E, Qian H, Liu P, Dong L, Rogozin IB, Redmond TM. Aberrant RNA splicing is the major pathogenic effect in a knock-in mouse model of the dominantly inherited c.1430A>G human RPE65 mutation. Hum Mutat 2019; 40:426-443. [PMID: 30628748 DOI: 10.1002/humu.23706] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/14/2018] [Accepted: 01/06/2019] [Indexed: 01/03/2023]
Abstract
Human RPE65 mutations cause a spectrum of retinal dystrophies that result in blindness. While RPE65 mutations have been almost invariably recessively inherited, a c.1430A>G (p.(D477G)) mutation has been reported to cause autosomal dominant retinitis pigmentosa (adRP). To study the pathogenesis of this human mutation, we have replicated the mutation in a knock-in (KI) mouse model using CRISPR/Cas9-mediated genome editing. Significantly, in contrast to human patients, heterozygous KI mice do not exhibit any phenotypes in visual function tests. When raised in regular vivarium conditions, homozygous KI mice display relatively undisturbed visual functions with minimal retinal structural changes. However, KI/KI mouse retinae are more sensitive to light exposure and exhibit signs of degenerative features when subjected to light stress. We find that instead of merely producing a missense mutant protein, the A>G nucleotide substitution greatly affects appropriate splicing of Rpe65 mRNA by generating an ectopic splice site in comparable context to the canonical one, thereby disrupting RPE65 protein expression. Similar splicing defects were also confirmed for the human RPE65 c.1430G mutant in an in vitro Exontrap assay. Our data demonstrate that a splicing defect is associated with c.1430G pathogenesis, and therefore provide insights in the therapeutic strategy for human patients.
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Affiliation(s)
- Yan Li
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
| | - Rachel Furhang
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
| | - Amanda Ray
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
| | - Todd Duncan
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
| | - Joseph Soucy
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
| | - Rashid Mahdi
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
| | - Vijender Chaitankar
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, NIH, Bethesda, Maryland
| | - Linn Gieser
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, NIH, Bethesda, Maryland
| | - Eugenia Poliakov
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
| | - Haohua Qian
- Visual Function Core, National Eye Institute, NIH, Bethesda, Maryland
| | - Pinghu Liu
- Genetic Engineering Core, National Eye Institute, NIH, Bethesda, Maryland
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, NIH, Bethesda, Maryland
| | - Igor B Rogozin
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, Maryland
| | - T Michael Redmond
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland
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7
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Henneman NF, Foster SL, Chrenek MA, Sellers JT, Wright CB, Schmidt RH, Nickerson JM, Boatright JH. Xanthohumol Protects Morphology and Function in a Mouse Model of Retinal Degeneration. Invest Ophthalmol Vis Sci 2018; 59:45-53. [PMID: 29305606 PMCID: PMC5756043 DOI: 10.1167/iovs.17-22132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Purpose To investigate whether treatment with xanthohumol (XN), the principal prenylated chalconoid from Humulus lupulus (hops), is protective in a mouse model of light-induced retinal degeneration (LIRD). Methods Mice (129S2/SvPasCrl) were intraperitoneally injected with vehicle or XN prior to toxic light exposure and every 3 days thereafter. Retinal function was assessed by electroretinograms at 1, 2, and 4 weeks following toxic light exposure. Visual acuity was tested by optokinetic tracking 1 week and 4 weeks after toxic light exposure. Retina sections were stained with hematoxylin and eosin for morphologic analysis or by TUNEL. Redox potentials were assessed in retinal tissue by measuring levels of cysteine (CYS), cystine (CYSS), glutathione (GSH), and glutathione disulfide (GSSG) using HPLC with fluorescence detection. Results Toxic light significantly suppressed retinal function and visual acuity, severely disrupted the photoreceptor cell layer, and significantly decreased the number of nuclei and increased the accumulation of TUNEL-labeled cells in the outer nuclear layer. These effects were prevented by XN treatment. Treatment with XN also maintained GSSG and CYSS redox potentials and the total CYS pool in retinas of mice undergoing toxic light exposure. Conclusions XN treatment partially preserved visual acuity and retinal function in the LIRD mouse. Preservation of retinal CYS and of GSSG and CYSS redox potentials may indicate that XN treatment induces an increased antioxidant response, but further experiments are needed to verify this potential mechanism. To our knowledge, this is the first study to report protective effects of XN in a model of retinal degeneration.
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Affiliation(s)
- Nathaniel F Henneman
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States.,Center for Visual and Neurorehabilitative Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
| | - Stephanie L Foster
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Micah A Chrenek
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Jana T Sellers
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Charles B Wright
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Robin H Schmidt
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - John M Nickerson
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States
| | - Jeffrey H Boatright
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, Georgia, United States.,Center for Visual and Neurorehabilitative Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
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8
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Fu X, Huu VAN, Duan Y, Kermany DS, Valentim CCS, Zhang R, Zhu J, Zhang CL, Sun X, Zhang K. Clinical applications of retinal gene therapies. PRECISION CLINICAL MEDICINE 2018; 1:5-20. [PMID: 35694125 PMCID: PMC8982485 DOI: 10.1093/pcmedi/pby004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 02/05/2023] Open
Abstract
Retinal degenerative diseases are a major cause of blindness. Retinal gene therapy is a
trail-blazer in the human gene therapy field, leading to the first FDA approved gene
therapy product for a human genetic disease. The application of Clustered Regularly
Interspaced Short Palindromic Repeat/Cas9 (CRISPR/Cas9)-mediated gene editing technology
is transforming the delivery of gene therapy. We review the history, present, and future
prospects of retinal gene therapy.
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Affiliation(s)
- Xin Fu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Viet Anh Nguyen Huu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Yaou Duan
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Daniel S Kermany
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Carolina C S Valentim
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Runze Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jie Zhu
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Charlotte L Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Xiaodong Sun
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Jiaodong University, Shanghai, China
| | - Kang Zhang
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
- Molecular Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
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9
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Markand S, Baskin NL, Chakraborty R, Landis E, Wetzstein SA, Donaldson KJ, Priyadarshani P, Alderson SE, Sidhu CS, Boatright JH, Iuvone PM, Pardue MT, Nickerson JM. IRBP deficiency permits precocious ocular development and myopia. Mol Vis 2016; 22:1291-1308. [PMID: 27829784 PMCID: PMC5082647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/25/2016] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Interphotoreceptor retinoid-binding protein (IRBP) is abundant in the subretinal space and binds retinoids and lipophilic molecules. The expression of IRBP begins precociously early in mouse eye development. IRBP-deficient (KO) mice show less cell death in the inner retinal layers of the retina before eyelid opening compared to wild-type C57BL/6J (WT) controls and eventually develop profound myopia. Thus, IRBP may play a role in eye development before visually-driven phenomena. We report comparative observations during the course of the natural development of eyes in WT and congenic IRBP KO mice that suggest IRBP is necessary at the early stages of mouse eye development for correct function and development to exist in later stages. METHODS We observed the natural development of congenic WT and IRBP KO mice, monitoring several markers of eye size and development, including haze and clarity of optical components in the eye, eye size, axial length, immunohistological markers of differentiation and eye development, visually guided behavior, and levels of a putative eye growth stop signal, dopamine. We conducted these measurements at several ages. Slit-lamp examinations were conducted at post-natal day (P)21. Fundus and spectral domain optical coherence tomography (SD-OCT) images were compared at P15, P30, P45, and P80. Enucleated eyes from P5 to P10 were measured for weight, and ocular dimensions were measured with a noncontact light-emitting diode (LED) micrometer. We counted the cells that expressed tyrosine hydroxylase (TH-positive cells) at P23-P36 using immunohistochemistry on retinal flatmounts. High-performance liquid chromatography (HPLC) was used to analyze the amounts of dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) at P7-P60. Monocular form deprivation in the right eye was induced using head-mounted goggles from P28 to P56. RESULTS Eye elongation and eye size in the IRBP KO mice began to increase at P7 compared to the WT mice. This difference increased until P12, and the difference was maintained thereafter. SD-OCT images in live mice confirmed previously reported retinal thinning of the outer nuclear layer in the IRBP KO mice compared to the WT mice from P15 to P80. Slit-lamp and fundoscopy examination outcomes did not differ between the WT and KO mice. SD-OCT measurements of the optical axis components showed that the only factor contributing to excess optical axis length was the depth of the vitreous body. No other component of optical axis length (including corneal thickness, anterior chamber depth, and lens thickness) was different from that of the WT mouse. The refractive power of the IRBP KO mice did not change in response to form deprivation. The number of retinal TH-positive cells was 28% greater in the IRBP KO retinas compared to the WT mice at P30. No significant differences were observed in the steady-state retinal DA or DOPAC levels or in the DOPAC/DA ratios between the WT and IRBP KO mice. CONCLUSIONS The IRBP KO mouse eye underwent precocious development and rapid eye size growth temporally about a day sooner than the WT mouse eye. Eye size began to differ between the WT and KO mice before eyelid opening, indicating no requirement for focus-dependent vision, and suggesting a developmental abnormality in the IRBP KO mouse eye that precedes form vision-dependent emmetropization. Additionally, the profoundly myopic KO eye did not respond to form deprivation compared to the non-deprived contralateral eye. Too much growth occurred in some parts of the eye, possibly upsetting a balance among size, differentiation, and focus-dependent growth suppression. Thus, the loss of IRBP may simply cause growth that is too rapid, possibly due to a lack of sequestration or buffering of morphogens that normally would bind to IRBP but are unbound in the IRBP KO eye. Despite the development of profound myopia, the DA levels in the IRBP KO mice were not statistically different from those in the WT mice, even with the excess of TH-positive cells in the IRBP KO mice compared to the WT mice. Overall, these data suggest that abnormal eye elongation in the IRBP KO mouse is independent of, precedes, and is epistatic to the process(es) of visually-driven refractive development.
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Affiliation(s)
- Shanu Markand
- Department of Ophthalmology, Emory University, Atlanta, GA
| | | | - Ranjay Chakraborty
- Department of Ophthalmology, Emory University, Atlanta, GA,Atlanta Veterans Administration Center of Visual and Neurocognitive Rehabilitation, Decatur, GA
| | - Erica Landis
- Atlanta Veterans Administration Center of Visual and Neurocognitive Rehabilitation, Decatur, GA,Neuroscience Program, Laney Graduate School, Emory University, Atlanta, GA
| | | | | | | | | | | | - Jeffrey H. Boatright
- Department of Ophthalmology, Emory University, Atlanta, GA,Atlanta Veterans Administration Center of Visual and Neurocognitive Rehabilitation, Decatur, GA
| | - P. Michael Iuvone
- Department of Ophthalmology, Emory University, Atlanta, GA,Department of Pharmacology, Emory University, Atlanta, GA
| | - Machelle T. Pardue
- Department of Ophthalmology, Emory University, Atlanta, GA,Atlanta Veterans Administration Center of Visual and Neurocognitive Rehabilitation, Decatur, GA,Neuroscience Program, Laney Graduate School, Emory University, Atlanta, GA,Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA
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10
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Xue Y, Shen SQ, Corbo JC, Kefalov VJ. Circadian and light-driven regulation of rod dark adaptation. Sci Rep 2015; 5:17616. [PMID: 26626567 PMCID: PMC4667277 DOI: 10.1038/srep17616] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/02/2015] [Indexed: 01/10/2023] Open
Abstract
Continuous visual perception and the dark adaptation of vertebrate photoreceptors after bright light exposure require recycling of their visual chromophore through a series of reactions in the retinal pigmented epithelium (RPE visual cycle). Light-driven chromophore consumption by photoreceptors is greater in daytime vs. nighttime, suggesting that correspondingly higher activity of the visual cycle may be required. However, as rod photoreceptors are saturated in bright light, the continuous turnover of their chromophore by the visual cycle throughout the day would not contribute to vision. Whether the recycling of chromophore that drives rod dark adaptation is regulated by the circadian clock and light exposure is unknown. Here, we demonstrate that mouse rod dark adaptation is slower during the day or after light pre-exposure. This surprising daytime suppression of the RPE visual cycle was accompanied by light-driven reduction in expression of Rpe65, a key enzyme of the RPE visual cycle. Notably, only rods in melatonin-proficient mice were affected by this daily visual cycle modulation. Our results demonstrate that the circadian clock and light exposure regulate the recycling of chromophore in the RPE visual cycle. This daily melatonin-driven modulation of rod dark adaptation could potentially protect the retina from light-induced damage during the day.
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Affiliation(s)
- Yunlu Xue
- Washington University School of Medicine, St. Louis, Missouri 63110, USA.,Department of Ophthalmology &Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.,Graduate Program in Division of Biological &Biomedical Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Susan Q Shen
- Washington University School of Medicine, St. Louis, Missouri 63110, USA.,Department of Pathology &Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.,Graduate Program in Division of Biological &Biomedical Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Joseph C Corbo
- Washington University School of Medicine, St. Louis, Missouri 63110, USA.,Department of Pathology &Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Vladimir J Kefalov
- Washington University School of Medicine, St. Louis, Missouri 63110, USA.,Department of Ophthalmology &Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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11
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Deming JD, Pak JS, Brown BM, Kim MK, Aung MH, Eom YS, Shin JA, Lee EJ, Pardue MT, Craft CM. Visual Cone Arrestin 4 Contributes to Visual Function and Cone Health. Invest Ophthalmol Vis Sci 2015; 56:5407-16. [PMID: 26284544 DOI: 10.1167/iovs.15-16647] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Visual arrestins (ARR) play a critical role in shutoff of rod and cone phototransduction. When electrophysiological responses are measured for a single mouse cone photoreceptor, ARR1 expression can substitute for ARR4 in cone pigment desensitization; however, each arrestin may also contribute its own, unique role to modulate other cellular functions. METHODS A combination of ERG, optokinetic tracking, immunohistochemistry, and immunoblot analysis was used to investigate the retinal phenotypes of Arr4 null mice (Arr4-/-) compared with age-matched control, wild-type mice. RESULTS When 2-month-old Arr4-/- mice were compared with wild-type mice, they had diminished visual acuity and contrast sensitivity, yet enhanced ERG flicker response and higher photopic ERG b-wave amplitudes. In contrast, in older Arr4-/- mice, all ERG amplitudes were significantly reduced in magnitude compared with age-matched controls. Furthermore, in older Arr4-/- mice, the total cone numbers decreased and cone opsin protein immunoreactive expression levels were significantly reduced, while overall photoreceptor outer nuclear layer thickness was unchanged. CONCLUSIONS Our study demonstrates that Arr4-/- mice display distinct phenotypic differences when compared to controls, suggesting that ARR4 modulates essential functions in high acuity vision and downstream cellular signaling pathways that are not fulfilled or substituted by the coexpression of ARR1, despite its high expression levels in all mouse cones. Without normal ARR4 expression levels, cones slowly degenerate with increasing age, making this a new model to study age-related cone dystrophy.
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Affiliation(s)
- Janise D Deming
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | - Joseph S Pak
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | - Bruce M Brown
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | - Moon K Kim
- Rehabilitation Research & Development Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia, United States
| | - Moe H Aung
- Neuroscience/Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Yun Sung Eom
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 4Dornsife College of Letters, Arts and Sciences, Univers
| | - Jung-A Shin
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 5Department of Anatomy, School of Medicine, Ewha Womans
| | - Eun-Jin Lee
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 6Department of Biomedical Engineering, University of Sou
| | - Machelle T Pardue
- Rehabilitation Research & Development Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia, United States 3Neuroscience/Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Cheryl Mae Craft
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 7Department of Cell & Neurobiology, Keck School of Medic
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12
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Psychophysical testing in rodent models of glaucomatous optic neuropathy. Exp Eye Res 2015; 141:154-63. [PMID: 26144667 DOI: 10.1016/j.exer.2015.06.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 06/08/2015] [Accepted: 06/29/2015] [Indexed: 12/14/2022]
Abstract
Processing of visual information begins in the retina, with photoreceptors converting light stimuli into neural signals. Ultimately, signals are transmitted to the brain through signaling networks formed by interneurons, namely bipolar, horizontal and amacrine cells providing input to retinal ganglion cells (RGCs), which form the optic nerve with their axons. As part of the chronic nature of glaucomatous optic neuropathy, the increasing and irreversible damage and ultimately loss of neurons, RGCs in particular, occurs following progressive damage to the optic nerve head (ONH), eventually resulting in visual impairment and visual field loss. There are two behavioral assays that are typically used to assess visual deficits in glaucoma rodent models, the visual water task and the optokinetic drum. The visual water task can assess an animal's ability to distinguish grating patterns that are associated with an escape from water. The optokinetic drum relies on the optomotor response, a reflex turning of the head and neck in the direction of the visual stimuli, which usually consists of rotating black and white gratings. This reflex is a physiological response critical for keeping the image stable on the retina. Driven initially by the neuronal input from direction-selective RGCs, this reflex is comprised of a number of critical sensory and motor elements. In the presence of repeatable and defined stimuli, this reflex is extremely well suited to analyze subtle changes in the circuitry and performance of retinal neurons. Increasing the cycles of these alternating gratings per degree, or gradually reducing the contrast of the visual stimuli, threshold levels can be determined at which the animal is no longer tracking the stimuli, and thereby visual function of the animal can be determined non-invasively. Integrating these assays into an array of outcome measures that determine multiple aspects of visual function is a central goal in vision research and can be realized, for example, by the combination of measuring optomotor reflex function with electroretinograms (ERGs) and optical coherence tomography (OCT) of the retina. These structure-function correlations in vivo are urgently needed to identify disease mechanisms as potential new targets for drug development. Such a combination of the experimental assessment of the optokinetic reflex (OKR) or optomotor response (OMR) with other measures of retinal structure and function is especially valuable for research on GON. The chronic progression of the disease is characterized by a gradual decrease in function accompanied by a concomitant increase in structural damage to the retina, therefore the assessment of subtle changes is key to determining the success of novel intervention strategies.
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13
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Li S, Izumi T, Hu J, Jin HH, Siddiqui AAA, Jacobson SG, Bok D, Jin M. Rescue of enzymatic function for disease-associated RPE65 proteins containing various missense mutations in non-active sites. J Biol Chem 2014; 289:18943-56. [PMID: 24849605 PMCID: PMC4081934 DOI: 10.1074/jbc.m114.552117] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Over 70 different missense mutations, including a dominant mutation, in RPE65 retinoid isomerase are associated with distinct forms of retinal degeneration; however, the disease mechanisms for most of these mutations have not been studied. Although some mutations have been shown to abolish enzyme activity, the molecular mechanisms leading to the loss of enzymatic function and retinal degeneration remain poorly understood. Here we show that the 26 S proteasome non-ATPase regulatory subunit 13 (PSMD13), a newly identified negative regulator of RPE65, plays a critical role in regulating pathogenicity of three mutations (L22P, T101I, and L408P) by mediating rapid degradation of mutated RPE65s via a ubiquitination- and proteasome-dependent non-lysosomal pathway. These mutant RPE65s were misfolded and formed aggregates or high molecular complexes via disulfide bonds. Interaction of PSMD13 with mutant RPE65s promoted degradation of misfolded but not properly folded mutant RPE65s. Many mutations, including L22P, T101I, and L408P, were mapped on non-active sites. Although their activities were very low, these mutant RPE65s were catalytically active and could be significantly rescued at low temperature, whereas mutant RPE65s with a distinct active site mutation could not be rescued under the same conditions. Sodium 4-phenylbutyrate and glycerol displayed a significant synergistic effect on the low temperature rescue of the mutant RPE65s by promoting proper folding, reducing aggregation, and increasing membrane association. Our results suggest that a low temperature eye mask and sodium 4-phenylbutyrate, a United States Food and Drug Administration-approved oral medicine, may provide a promising "protein repair therapy" that can enhance the efficacy of gene therapy by reducing the cytotoxic effect of misfolded mutant RPE65s.
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Affiliation(s)
- Songhua Li
- From the Department of Ophthalmology and Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Tadahide Izumi
- Graduate Center for Toxicology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Jane Hu
- Jules Stein Eye Institute and Department of Neurobiology, University of California, Los Angeles, California 90095
| | - Heather H Jin
- Department of Biology, Washington University, St. Louis, Missouri 63130
| | | | - Samuel G Jacobson
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Dean Bok
- Jules Stein Eye Institute and Department of Neurobiology, University of California, Los Angeles, California 90095
| | - Minghao Jin
- From the Department of Ophthalmology and Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112,
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