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Procyk CA, Melati A, Ribeiro J, Liu J, Branch MJ, Delicata JD, Tariq M, Kalarygrou AA, Kapadia J, Khorsani MM, West EL, Smith AJ, Gonzalez-Cordero A, Ali RR, Pearson RA. Human cone photoreceptor transplantation stimulates remodeling and restores function in AIPL1 model of end-stage Leber congenital amaurosis. Stem Cell Reports 2025; 20:102470. [PMID: 40154478 PMCID: PMC12069896 DOI: 10.1016/j.stemcr.2025.102470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2024] [Revised: 03/03/2025] [Accepted: 03/03/2025] [Indexed: 04/01/2025] Open
Abstract
Photoreceptor degeneration is a leading cause of untreatable sight loss. Previously, we showed that human pluripotent stem cell-derived cone photoreceptors (hCones) can rescue retinal function in the Rd1 mouse model of rod-cone dystrophy. However, retinal degenerations display markedly different severities and concomitant remodeling of the remaining retina; for photoreceptor replacement therapy to be broadly effective, it must work for a variety of disease phenotypes. Here, we sought to rescue the Aipl1-/- model of Leber congenital amaurosis, a particularly fast, severe condition. After transplantation of hCones, host cone bipolar cells underwent extensive remodeling and formed nascent synaptic-like connections. Electrophysiological recordings showed robust rescue of light-evoked activity across visually relevant photopic intensities, and treated mice exhibited visually evoked optokinetic head-tracking behavior. Thus, human cone photoreceptor replacement therapy is feasible even in very severe cases of retinal dystrophy, offering promise as a disease-agnostic therapy in Leber congenital amaurosis (LCA) and in other advanced retinal degenerations.
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Affiliation(s)
- Christopher A Procyk
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Anna Melati
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Joana Ribeiro
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Jingshu Liu
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Matthew J Branch
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Jamie D Delicata
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Menahil Tariq
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Aikaterini A Kalarygrou
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Jessica Kapadia
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Majid Moshtagh Khorsani
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Emma L West
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Alexander J Smith
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Anai Gonzalez-Cordero
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Robin R Ali
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Rachael A Pearson
- Ocular Cell and Gene Therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK.
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Michaelides M, Laich Y, Wong SC, Oluonye N, Zaman S, Kumaran N, Kalitzeos A, Petrushkin H, Georgiou M, Tailor V, Pabst M, Staeubli K, Maimon-Mor RO, Jones PR, Scholte SH, Georgiadis A, van der Spuy J, Naylor S, Forbes A, Dekker TM, Arulmuthu ER, Smith AJ, Ali RR, Bainbridge JWB. Gene therapy in children with AIPL1-associated severe retinal dystrophy: an open-label, first-in-human interventional study. Lancet 2025; 405:648-657. [PMID: 39986747 DOI: 10.1016/s0140-6736(24)02812-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2024] [Revised: 11/25/2024] [Accepted: 12/19/2024] [Indexed: 02/24/2025]
Abstract
BACKGROUND Retinal dystrophy caused by genetic deficiency of AIPL1 causes severe and rapidly progressive impairment of sight from birth. We sought to evaluate whether early intervention by gene supplementation therapy was safe and could improve outcomes in children with this condition. METHODS This non-randomised, single-arm, clinical study conducted in the UK involved four children aged 1·0-2·8 years with severe retinal dystrophy associated with biallelic disease-causing sequence variants in AIPL1. We designed a recombinant adeno-associated viral vector comprising the human AIPL1 coding sequence driven by a human rhodopsin kinase promoter region (rAAV8.hRKp.AIPL1). The product was manufactured under a Specials Licence from the Medicines and Health products Regulatory Authority (UK) and made available to affected children with local ethics approval. We administered the product to one eye of each child by subretinal injection. The children were prescribed oral prednisolone to protect against harm from inflammation. Outcome measures included visual acuity (as assessed with a novel touchscreen test), functional vision (assessed by observing and recording the children's visual behaviour and their ability to perform simple vision-guided tasks), visual evoked potentials (assessed by recording cortical electrophysiological responses to full-screen black-and-white flickering stimuli), and retinal structure (assessed with handheld optical coherence tomography [OCT] and widefield fundus imaging). To identify adverse effects, including inflammation and retinal detachment, we conducted ocular examinations using slit-lamp biomicroscopy and dilated fundoscopy. Safety was further assessed by testing of visual acuity, ophthalmoscopy, handheld OCT and widefield fundus imaging. FINDINGS Patients were selected for treatment between July 12, 2019, and March 16, 2020. Before intervention, the children's binocular visual acuities were limited to perception of light. At a mean of 3·5 years (range 3·0-4·1) after intervention, the visual acuities of the children's treated eyes had improved to a mean of 0·9 logarithm of the minimal angle of the minimum angle of resolution ([logMAR] range 0·8-1·0); visual acuities before intervention were equivalent to 2·7 logMAR. In contrast, the visual acuities of the children's untreated eyes became unmeasurable at the final follow-up. In the two children able to comply with testing, an objective test of visual acuity confirmed improvements in visual function, and measurement of visual evoked potentials showed enhanced activity of the visual cortex, specific to the treated eyes. In three of the children, structural lamination of the outer retina was better preserved in the treated eye than in the untreated eye, and, for all four children, retinal thickness appeared better preserved in the treated eye than in the untreated eye. The treated eye of one child developed cystoid macular oedema. No other safety concerns were identified. INTERPRETATION Our findings indicate that young children with AIPL1-related retinal dystrophy benefited substantially from subretinal administration of rAAV8.hRKp.AIPL1, with improved visual acuity and functional vision and evidence of some protection against progressive retinal degeneration, without serious adverse effects. FUNDING UK National Institute for Health Research and Moorfields Eye Charity.
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Affiliation(s)
- Michel Michaelides
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK.
| | - Yannik Laich
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK; Eye Center, Faculty of Medicine, Freiburg University, Freiburg, Germany
| | - Sui Chien Wong
- NIHR Moorfields Biomedical Research Centre, London, UK; Great Ormond Street Hospital for Children, London, UK
| | - Ngozi Oluonye
- NIHR Moorfields Biomedical Research Centre, London, UK; Great Ormond Street Hospital for Children, London, UK
| | - Serena Zaman
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - Neruban Kumaran
- UCL Institute of Ophthalmology, University College London, London, UK; Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Angelos Kalitzeos
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - Harry Petrushkin
- NIHR Moorfields Biomedical Research Centre, London, UK; Great Ormond Street Hospital for Children, London, UK
| | - Michalis Georgiou
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - Vijay Tailor
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK; Experimental Psychology, University College London, London, UK
| | - Marc Pabst
- UCL Institute of Ophthalmology, University College London, London, UK; Experimental Psychology, University College London, London, UK
| | - Kim Staeubli
- UCL Institute of Ophthalmology, University College London, London, UK; Experimental Psychology, University College London, London, UK
| | - Roni O Maimon-Mor
- UCL Institute of Ophthalmology, University College London, London, UK; Experimental Psychology, University College London, London, UK
| | - Peter R Jones
- UCL Institute of Ophthalmology, University College London, London, UK; Department of Optometry and Visual Sciences, City St George's, University of London, London, UK
| | - Steven H Scholte
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands
| | | | | | | | | | - Tessa M Dekker
- UCL Institute of Ophthalmology, University College London, London, UK; Experimental Psychology, University College London, London, UK
| | | | - Alexander J Smith
- UCL Institute of Ophthalmology, University College London, London, UK; Centre for Gene Therapy and Regenerative Medicine, King's College London, London, UK
| | - Robin R Ali
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK; Guy's and St Thomas' NHS Foundation Trust, London, UK; Centre for Gene Therapy and Regenerative Medicine, King's College London, London, UK.
| | - James W B Bainbridge
- NIHR Moorfields Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, University College London, London, UK.
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Dey PN, Singh N, Zelinger L, Batz Z, Nellissery J, White Carreiro ND, Qian H, Li T, Fariss RN, Dong L, Swaroop A. Loss of paired immunoglobin-like type 2 receptor B gene associated with age-related macular degeneration impairs photoreceptor function in mouse retina. Hum Mol Genet 2025; 34:64-76. [PMID: 39532089 PMCID: PMC12034095 DOI: 10.1093/hmg/ddae161] [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: 08/10/2024] [Revised: 10/10/2024] [Accepted: 11/01/2024] [Indexed: 11/16/2024] Open
Abstract
Genome-wide association studies have uncovered mostly non-coding variants at over 60 genetic loci linked to susceptibility for age-related macular degeneration (AMD). To ascertain the causal gene at the PILRB/PILRA locus, we used a CRISPR strategy to produce germline deletions in the mouse paired immunoglobin-like type 2 receptor (Pilr) genes that encode highly related activating (PILRB) and inhibitory (PILRA) receptors. We show that a combined loss of Pilrb1 and Pilrb2, but not Pilra, leads to an early but relatively stationary defect as the electroretinography (ERG) amplitudes of Pilrb1/2-/- mice exhibit a marked reduction as early as postnatal day 15 and do not show additional significant decrease at 3 and 12-months. No alterations are evident in Müller glia, microglia, bipolar, amacrine and horizontal cells based on immunohistochemistry using cell-type specific markers. PILRB immunostaining is specifically detected at the proximal part of photoreceptor outer segment. Reduced expression of select calcium-regulated phototransduction and synapse-associated proteins, including GCAP1 and 2, PDE6b, AIPL1, PSD95, and CTBP1 indicates dysregulation of calcium homeostasis as a possible mechanism of retinal phenotype in Pilrb1/2-/- mice. Our studies suggest a novel function of PILRB in retinal photoreceptors and an association of PILRB, but not PILRA, with AMD pathogenesis.
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Affiliation(s)
- Partha Narayan Dey
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Nivedita Singh
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Lina Zelinger
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Zachary Batz
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Jacob Nellissery
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Noor D White Carreiro
- Biological Imaging Core, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Haohua Qian
- Visual Function Core Facility, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Tiansen Li
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Robert N Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
| | - Anand Swaroop
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, MSC0610, Bethesda, MD 20892, United States
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Zhang Q, Sun J, Liu Z, Wang H, Zhou H, Liu W, Jia H, Li N, Li T, Wang F, Sun X. Clinical and Molecular Characterization of AIPL1-Associated Leber Congenital Amaurosis/Early-Onset Severe Retinal Dystrophy. Am J Ophthalmol 2024; 266:235-247. [PMID: 38880373 DOI: 10.1016/j.ajo.2024.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 06/07/2024] [Accepted: 06/07/2024] [Indexed: 06/18/2024]
Abstract
PURPOSE This study aimed to characterize the clinical features, genetic findings, and genotype-phenotype correlations of patients with Leber congenital amaurosis (LCA) or early-onset severe retinal dystrophy (EOSRD) harboring biallelic AIPL1 pathogenic variants. DESIGN Retrospective case series. METHODS This study consecutively enrolled 51 patients from 47 families with a clinical diagnosis of LCA/EOSRD harboring disease-causing variants in the AIPL1 gene, from October 2021 to September 2023. Molecular genetic findings, medical history, and ophthalmic evaluation including visual acuity (VA), multimodal retinal imaging, and electrophysiologic assessment were reviewed. RESULTS Of the 51 patients (32 with LCA and 19 with EOSRD), 27 (53%) were females, and age at last review ranged from 0.5 to 58.4 years. We identified 28 disease-causing AIPL1 variants, with 18 being novel. In patients with EOSRD, the mean (range) VA was 1.3 (0.7-2.7) logMAR and 1.3 (0.5-2.3) logMAR for right and left eyes respectively, with an average annual decline of 0.03 logMAR (R2 = 0.7547, P < .01). For patients with LCA, the VA ranged from light perception to counting fingers. Optical coherence tomography imaging demonstrated preservation of foveal ellipsoid zone in the 5 youngest EOSRD patients and 9 LCA children. Electroretinography showed severe cone-rod patterns in 78.6% (11/14) of patients with EOSRD, while classical extinguished pattern was documented in all patients with LCA available for the examination. The most common mutation was the nonsense variants of c.421C>T, with an allele frequency of 53.9%. All patients with EOSRD carried at least one missense mutation, of whom 13 identified with c.152A>G and 5 with c.572T>C. Twenty-six patients with LCA harbored two null AIPL1 variants, while 18 were homozygous for c.421C>T and 6 were heterozygous for c.421C>T with another loss-of-function variant. CONCLUSIONS This study reveals distinct clinical features and variation spectrum between AIPL1-associated LCA and EOSRD. Patients harboring at least one nonnull mutation, especially c.152A>G and c.572T>C, were significantly more likely to have a milder EOSRD phenotype than those with two null mutations. Residual foveal outer retinal structure observed in the youngest proportion of patients suggests an early window for gene augmentation therapy.
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Affiliation(s)
- Quan Zhang
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China
| | - Junran Sun
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China
| | - Zishi Liu
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China
| | - Hong Wang
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China
| | - Hao Zhou
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China
| | - Wenjia Liu
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China
| | - Huixun Jia
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China; Shanghai Engineering Center for Visual Science and Photomedicine (HJ, FW, and XS), Shanghai, China
| | - Ningdong Li
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China
| | - Tong Li
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China.
| | - Fenghua Wang
- Shanghai Engineering Center for Visual Science and Photomedicine (HJ, FW, and XS), Shanghai, China; Innostellar Biotherapeutics Co., Ltd (FW), Shanghai, China
| | - Xiaodong Sun
- From the Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (QZ, JS, ZL, HW, HZ, WL, HJ, NL, TL, and XS), Shanghai, China; National Clinical Research Center for Ophthalmic Diseases (QZ, JS, ZL, HW, WL, HJ, NL, TL, and XS), Shanghai, China; Shanghai Engineering Center for Visual Science and Photomedicine (HJ, FW, and XS), Shanghai, China; Shanghai Key Laboratory of Fundus Diseases (XS), Shanghai, China.
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Ashok S, Ramachandra Rao S. Updates on protein-prenylation and associated inherited retinopathies. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1410874. [PMID: 39026984 PMCID: PMC11254824 DOI: 10.3389/fopht.2024.1410874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 06/13/2024] [Indexed: 07/20/2024]
Abstract
Membrane-anchored proteins play critical roles in cell signaling, cellular architecture, and membrane biology. Hydrophilic proteins are post-translationally modified by a diverse range of lipid molecules such as phospholipids, glycosylphosphatidylinositol, and isoprenes, which allows their partition and anchorage to the cell membrane. In this review article, we discuss the biochemical basis of isoprenoid synthesis, the mechanisms of isoprene conjugation to proteins, and the functions of prenylated proteins in the neural retina. Recent discovery of novel prenyltransferases, prenylated protein chaperones, non-canonical prenylation-target motifs, and reversible prenylation is expected to increase the number of inherited systemic and blinding diseases with aberrant protein prenylation. Recent important investigations have also demonstrated the role of several unexpected regulators (such as protein charge, sequence/protein-chaperone interaction, light exposure history) in the photoreceptor trafficking of prenylated proteins. Technical advances in the investigation of the prenylated proteome and its application in vision research are discussed. Clinical updates and technical insights into known and putative prenylation-associated retinopathies are provided herein. Characterization of non-canonical prenylation mechanisms in the retina and retina-specific prenylated proteome is fundamental to the understanding of the pathogenesis of protein prenylation-associated inherited blinding disorders.
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Affiliation(s)
- Sudhat Ashok
- Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY, United States
| | - Sriganesh Ramachandra Rao
- Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY, United States
- Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY, United States
- Research Service, VA Western New York Healthcare System, Buffalo, NY, United States
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Kurzawa-Akanbi M, Tzoumas N, Corral-Serrano JC, Guarascio R, Steel DH, Cheetham ME, Armstrong L, Lako M. Pluripotent stem cell-derived models of retinal disease: Elucidating pathogenesis, evaluating novel treatments, and estimating toxicity. Prog Retin Eye Res 2024; 100:101248. [PMID: 38369182 DOI: 10.1016/j.preteyeres.2024.101248] [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: 12/07/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Blindness poses a growing global challenge, with approximately 26% of cases attributed to degenerative retinal diseases. While gene therapy, optogenetic tools, photosensitive switches, and retinal prostheses offer hope for vision restoration, these high-cost therapies will benefit few patients. Understanding retinal diseases is therefore key to advance effective treatments, requiring in vitro models replicating pathology and allowing quantitative assessments for drug discovery. Pluripotent stem cells (PSCs) provide a unique solution given their limitless supply and ability to differentiate into light-responsive retinal tissues encompassing all cell types. This review focuses on the history and current state of photoreceptor and retinal pigment epithelium (RPE) cell generation from PSCs. We explore the applications of this technology in disease modelling, experimental therapy testing, biomarker identification, and toxicity studies. We consider challenges in scalability, standardisation, and reproducibility, and stress the importance of incorporating vasculature and immune cells into retinal organoids. We advocate for high-throughput automation in data acquisition and analyses and underscore the value of advanced micro-physiological systems that fully capture the interactions between the neural retina, RPE, and choriocapillaris.
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7
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Sai H, Ollington B, Rezek FO, Chai N, Lane A, Georgiadis T, Bainbridge J, Michaelides M, Sacristan-Reviriego A, Perdigão PR, Leung A, van der Spuy J. Effective AAV-mediated gene replacement therapy in retinal organoids modeling AIPL1-associated LCA4. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102148. [PMID: 38439910 PMCID: PMC10910061 DOI: 10.1016/j.omtn.2024.102148] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 02/12/2024] [Indexed: 03/06/2024]
Abstract
Biallelic variations in the aryl hydrocarbon receptor interacting protein-like 1 (AIPL1) gene cause Leber congenital amaurosis subtype 4 (LCA4), an autosomal recessive early-onset severe retinal dystrophy that leads to the rapid degeneration of retinal photoreceptors and the severe impairment of sight within the first few years of life. Currently, there is no treatment or cure for AIPL1-associated LCA4. In this study, we investigated the potential of adeno-associated virus-mediated AIPL1 gene replacement therapy in two previously validated human retinal organoid (RO) models of LCA4. We report here that photoreceptor-specific AIPL1 gene replacement therapy, currently being tested in a first-in-human application, effectively rescued molecular features of AIPL1-associated LCA4 in these models. Notably, the loss of retinal phosphodiesterase 6 was rescued and elevated cyclic guanosine monophosphate (cGMP) levels were reduced following treatment. Transcriptomic analysis of untreated and AAV-transduced ROs revealed transcriptomic changes in response to elevated cGMP levels and viral infection, respectively. Overall, this study supports AIPL1 gene therapy as a promising therapeutic intervention for LCA4.
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Affiliation(s)
- Hali Sai
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Bethany Ollington
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Farah O. Rezek
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Niuzheng Chai
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | | | | | - James Bainbridge
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- NIHR Moorfields Biomedical Research Centre, London EC1V 2PD, UK
| | - Michel Michaelides
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- NIHR Moorfields Biomedical Research Centre, London EC1V 2PD, UK
| | - Almudena Sacristan-Reviriego
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- Institute of Clinical Trials and Methodology, University College London, London WC1V 6LJ, UK
| | - Pedro R.L. Perdigão
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Amy Leung
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Jacqueline van der Spuy
- University College London Institute of Ophthalmology, University College London, London EC1V 9EL, UK
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Bighinati A, Adani E, Stanzani A, D’Alessandro S, Marigo V. Molecular mechanisms underlying inherited photoreceptor degeneration as targets for therapeutic intervention. Front Cell Neurosci 2024; 18:1343544. [PMID: 38370034 PMCID: PMC10869517 DOI: 10.3389/fncel.2024.1343544] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/16/2024] [Indexed: 02/20/2024] Open
Abstract
Retinitis pigmentosa (RP) is a form of retinal degeneration characterized by primary degeneration of rod photoreceptors followed by a secondary cone loss that leads to vision impairment and finally blindness. This is a rare disease with mutations in several genes and high genetic heterogeneity. A challenging effort has been the characterization of the molecular mechanisms underlying photoreceptor cell death during the progression of the disease. Some of the cell death pathways have been identified and comprise stress events found in several neurodegenerative diseases such as oxidative stress, inflammation, calcium imbalance and endoplasmic reticulum stress. Other cell death mechanisms appear more relevant to photoreceptor cells, such as high levels of cGMP and metabolic changes. Here we review some of the cell death pathways characterized in the RP mutant retina and discuss preclinical studies of therapeutic approaches targeting the molecular outcomes that lead to photoreceptor cell demise.
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Affiliation(s)
- Andrea Bighinati
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Elisa Adani
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Agnese Stanzani
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Sara D’Alessandro
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Center for Neuroscience and Neurotechnology, Modena, Italy
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9
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Singh S, Srivastava D, Boyd K, Artemyev NO. Reconstitution of the phosphodiesterase 6 maturation process important for photoreceptor cell function. J Biol Chem 2024; 300:105576. [PMID: 38110033 PMCID: PMC10819763 DOI: 10.1016/j.jbc.2023.105576] [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: 10/16/2023] [Revised: 12/01/2023] [Accepted: 12/10/2023] [Indexed: 12/20/2023] Open
Abstract
The sixth family phosphodiesterases (PDE6) are principal effector enzymes of the phototransduction cascade in rods and cones. Maturation of nascent PDE6 protein into a functional enzyme relies on a coordinated action of ubiquitous chaperone HSP90, its specialized cochaperone aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1), and the regulatory Pγ-subunit of PDE6. Deficits in PDE6 maturation and function underlie severe visual disorders and blindness. Here, to elucidate the roles of HSP90, AIPL1, and Pγ in the maturation process, we developed the heterologous expression system of human cone PDE6C in insect cells allowing characterization of the purified enzyme. We demonstrate that in the absence of Pγ, HSP90, and AIPL1 convert the inactive and aggregating PDE6C species into dimeric PDE6C that is predominantly misassembled. Nonetheless, a small fraction of PDE6C is properly assembled and fully functional. From the analysis of mutant mice that lack both rod Pγ and PDE6C, we conclude that, in contrast to the cone enzyme, no maturation of rod PDE6AB occurs in the absence of Pγ. Co-expression of PDE6C with AIPL1 and Pγ in insect cells leads to a fully mature enzyme that is equivalent to retinal PDE6. Lastly, using immature PDE6C and purified chaperone components, we reconstituted the process of the client maturation in vitro. Based on this analysis we propose a scheme for the PDE6 maturation process.
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Affiliation(s)
- Sneha Singh
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Dhiraj Srivastava
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Kimberly Boyd
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA; Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
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10
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Liang Y, Sun X, Duan C, Tang S, Chen J. Application of patient-derived induced pluripotent stem cells and organoids in inherited retinal diseases. Stem Cell Res Ther 2023; 14:340. [PMID: 38012786 PMCID: PMC10683306 DOI: 10.1186/s13287-023-03564-5] [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: 08/29/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
Inherited retinal diseases (IRDs) can induce severe sight-threatening retinal degeneration and impose a considerable economic burden on patients and society, making efforts to cure blindness imperative. Transgenic animals mimicking human genetic diseases have long been used as a primary research tool to decipher the underlying pathogenesis, but there are still some obvious limitations. As an alternative strategy, patient-derived induced pluripotent stem cells (iPSCs), particularly three-dimensional (3D) organoid technology, are considered a promising platform for modeling different forms of IRDs, including retinitis pigmentosa, Leber congenital amaurosis, X-linked recessive retinoschisis, Batten disease, achromatopsia, and best vitelliform macular dystrophy. Here, this paper focuses on the status of patient-derived iPSCs and organoids in IRDs in recent years concerning disease modeling and therapeutic exploration, along with potential challenges for translating laboratory research to clinical application. Finally, the importance of human iPSCs and organoids in combination with emerging technologies such as multi-omics integration analysis, 3D bioprinting, or microfluidic chip platform are highlighted. Patient-derived retinal organoids may be a preferred choice for more accurately uncovering the mechanisms of human retinal diseases and will contribute to clinical practice.
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Affiliation(s)
- Yuqin Liang
- Aier Eye Institute, Changsha, 410015, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Xihao Sun
- Aier Eye Institute, Changsha, 410015, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Chunwen Duan
- Aier Eye Institute, Changsha, 410015, China
- Changsha Aier Eye Hospital, Changsha, 410015, China
| | - Shibo Tang
- Aier Eye Institute, Changsha, 410015, China.
- Changsha Aier Eye Hospital, Changsha, 410015, China.
| | - Jiansu Chen
- Aier Eye Institute, Changsha, 410015, China.
- Changsha Aier Eye Hospital, Changsha, 410015, China.
- Key Laboratory for Regenerative Medicine, Ministry of Education, Jinan University, Guangzhou, 510632, China.
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11
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Moakedi F, Aljammal R, Poria D, Saravanan T, Rhodes SB, Reid C, Guan T, Kefalov VJ, Ramamurthy V. Prenylation is essential for the enrichment of cone phosphodiesterase-6 (PDE6) in outer segments and efficient cone phototransduction. Hum Mol Genet 2023; 32:2735-2750. [PMID: 37384398 PMCID: PMC10460490 DOI: 10.1093/hmg/ddad108] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/01/2023] Open
Abstract
Phosphodiesterase-6 (PDE6) is the key phototransduction effector enzyme residing in the outer segment (OS) of photoreceptors. Cone PDE6 is a tetrameric protein consisting of two inhibitory subunits (γ') and two catalytic subunits (α'). The catalytic subunit of cone PDE6 contains a C-terminus prenylation motif. Deletion of PDE6α' C-terminal prenylation motif is linked to achromatopsia (ACHM), a type of color blindness in humans. However, mechanisms behind the disease and roles for lipidation of cone PDE6 in vision are unknown. In this study, we generated two knock-in mouse models expressing mutant variants of cone PDE6α' lacking the prenylation motif (PDE6α'∆C). We find that the C-terminal prenylation motif is the primary determinant for the association of cone PDE6 protein with membranes. Cones from PDE6α'∆C homozygous mice are less sensitive to light, and their response to light is delayed, whereas cone function in heterozygous PDE6α'∆C/+ mice is unaffected. Surprisingly, the expression level and assembly of cone PDE6 protein were unaltered in the absence of prenylation. Unprenylated assembled cone PDE6 in PDE6α'∆C homozygous animals is mislocalized and enriched in the cone inner segment and synaptic terminal. Interestingly, the disk density and the overall length of cone OS in PDE6α'∆C homozygous mutants are altered, highlighting a novel structural role for PDE6 in maintaining cone OS length and morphology. The survival of cones in the ACHM model generated in this study bodes well for gene therapy as a treatment option for restoring vision in patients with similar mutations in the PDE6C gene.
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Affiliation(s)
- Faezeh Moakedi
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Rawaa Aljammal
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Deepak Poria
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA 92697, USA
| | - Thamaraiselvi Saravanan
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Scott B Rhodes
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Chyanne Reid
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Tongju Guan
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Vladimir J Kefalov
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA 92697, USA
| | - Visvanathan Ramamurthy
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
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12
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Munezero D, Aliff H, Salido E, Saravanan T, Sanzhaeva U, Guan T, Ramamurthy V. HSP90α is needed for the survival of rod photoreceptors and regulates the expression of rod PDE6 subunits. J Biol Chem 2023; 299:104809. [PMID: 37172722 PMCID: PMC10250166 DOI: 10.1016/j.jbc.2023.104809] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
Heat shock protein 90 (HSP90) is an abundant molecular chaperone that regulates the stability of a small set of proteins essential in various cellular pathways. Cytosolic HSP90 has two closely related paralogs: HSP90α and HSP90β. Due to the structural and sequence similarities of cytosolic HSP90 paralogs, identifying the unique functions and substrates in the cell remains challenging. In this article, we assessed the role of HSP90α in the retina using a novel HSP90α murine knockout model. Our findings show that HSP90α is essential for rod photoreceptor function but was dispensable in cone photoreceptors. In the absence of HSP90α, photoreceptors developed normally. We observed rod dysfunction in HSP90α knockout at 2 months with the accumulation of vacuolar structures, apoptotic nuclei, and abnormalities in the outer segments. The decline in rod function was accompanied by progressive degeneration of rod photoreceptors that was complete at 6 months. The deterioration in cone function and health was a "bystander effect" that followed the degeneration of rods. Tandem mass tag proteomics showed that HSP90α regulates the expression levels of <1% of the retinal proteome. More importantly, HSP90α was vital in maintaining rod PDE6 and AIPL1 cochaperone levels in rod photoreceptor cells. Interestingly, cone PDE6 levels were unaffected. The robust expression of HSP90β paralog in cones likely compensates for the loss of HSP90α. Overall, our study demonstrated the critical need for HSP90α chaperone in the maintenance of rod photoreceptors and showed potential substrates regulated by HSP90α in the retina.
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Affiliation(s)
- Daniella Munezero
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA; Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Hunter Aliff
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Ezequiel Salido
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Thamaraiselvi Saravanan
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Urikhan Sanzhaeva
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Tongju Guan
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Visvanathan Ramamurthy
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA; Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA.
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13
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ZP3 and AIPL1 participate in GVBD of mouse oocytes by affecting the nuclear membrane localization and maturation of farnesylated prelamin A. ZYGOTE 2023; 31:140-148. [PMID: 36533678 DOI: 10.1017/s0967199422000612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The low maturation rate of oocytes is an important reason for female infertility and failure of assisted pregnancy. The germinal vesicle breakdown (GVBD) is a landmark event of oocyte maturation. In our previous studies, we found that zona pellucida 3 (ZP3) was strongly concentrated in the nuclear region of germinal vesicle (GV) oocytes and interacted with aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) and lamin A to promote GVBD. In the current study, we found that lamin A is mainly concentrated in the nuclear membrane. When ZP3 is knocked down, lamin A will be partially transferred to the nucleus of oocytes. The prelamin A is increased in both the nuclear membrane and nucleus, while phosphorylated lamin A (p-lamin A) is significantly reduced. AIPL1 was also proved to accumulate in the GV region of oocytes, and ZP3 deletion can significantly inhibit the aggregation of AIPL1 in the nuclear region. Similar to ZP3 knockdown, the absence of AIPL1 resulted in a decrease in the occurrence of GVBD, an increase in the amount of prelamin A, and a significant decrease in p-lamin A in oocytes developed in vitro. Finally, we propose the hypothesis that ZP3 can stabilize farnesylated prelamin A on the nuclear membrane of AIPL1, and promote its further processing into mature lamin A, therefore promoting the occurrence of GVBD. This study may be an important supplement for the mechanism of oocyte meiotic resumption and provide new diagnostic targets and treatment clues for infertility patients with oocyte maturation disorder.
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14
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Perdigão PRL, Ollington B, Sai H, Leung A, Sacristan-Reviriego A, van der Spuy J. Retinal Organoids from an AIPL1 CRISPR/Cas9 Knockout Cell Line Successfully Recapitulate the Molecular Features of LCA4 Disease. Int J Mol Sci 2023; 24:ijms24065912. [PMID: 36982987 PMCID: PMC10057647 DOI: 10.3390/ijms24065912] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/27/2023] [Accepted: 03/07/2023] [Indexed: 03/30/2023] Open
Abstract
Aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) is expressed in photoreceptors where it facilitates the assembly of phosphodiesterase 6 (PDE6) which hydrolyses cGMP within the phototransduction cascade. Genetic variations in AIPL1 cause type 4 Leber congenital amaurosis (LCA4), which presents as rapid loss of vision in early childhood. Limited in vitro LCA4 models are available, and these rely on patient-derived cells harbouring patient-specific AIPL1 mutations. While valuable, the use and scalability of individual patient-derived LCA4 models may be limited by ethical considerations, access to patient samples and prohibitive costs. To model the functional consequences of patient-independent AIPL1 mutations, CRISPR/Cas9 was implemented to produce an isogenic induced pluripotent stem cell line harbouring a frameshift mutation in the first exon of AIPL1. Retinal organoids were generated using these cells, which retained AIPL1 gene transcription, but AIPL1 protein was undetectable. AIPL1 knockout resulted in a decrease in rod photoreceptor-specific PDE6α and β, and increased cGMP levels, suggesting downstream dysregulation of the phototransduction cascade. The retinal model described here provides a novel platform to assess functional consequences of AIPL1 silencing and measure the rescue of molecular features by potential therapeutic approaches targeting mutation-independent pathogenesis.
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Affiliation(s)
- Pedro R L Perdigão
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Bethany Ollington
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Hali Sai
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Amy Leung
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
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15
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Srivastava D, Yadav RP, Singh S, Boyd K, Artemyev NO. Unique interface and dynamics of the complex of HSP90 with a specialized cochaperone AIPL1. Structure 2023; 31:309-317.e5. [PMID: 36657440 PMCID: PMC9992320 DOI: 10.1016/j.str.2022.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/06/2022] [Accepted: 12/23/2022] [Indexed: 01/19/2023]
Abstract
Photoreceptor phosphodiesterase PDE6 is central for visual signal transduction. Maturation of PDE6 depends on a specialized chaperone complex of HSP90 with aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1). Disruption of PDE6 maturation underlies a severe form of retina degeneration. Here, we report a 3.9 Å cryoelectron microscopy (cryo-EM) structure of the complex of HSP90 with AIPL1. This structure reveals a unique interaction of the FK506-binding protein (FKBP)-like domain of AIPL1 with HSP90 at its dimer interface. Unusually, the N terminus AIPL1 inserts into the HSP90 lumen in a manner that was observed previously for HSP90 clients. Deletion of the 7 N-terminal residues of AIPL1 decreased its ability to cochaperone PDE6. Multi-body refinement of the cryo-EM data indicated large swing-like movements of AIPL1-FKBP. Modeling the complex of HSP90 with AIPL1 using crosslinking constraints indicated proximity of the mobile tetratricopeptide repeat (TPR) domain with the C-terminal domain of HSP90. Our study establishes a framework for future structural studies of PDE6 maturation.
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Affiliation(s)
- Dhiraj Srivastava
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Ravi P Yadav
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Sneha Singh
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Kimberly Boyd
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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16
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Prodromou C, Aran-Guiu X, Oberoi J, Perna L, Chapple JP, van der Spuy J. HSP70-HSP90 Chaperone Networking in Protein-Misfolding Disease. Subcell Biochem 2023; 101:389-425. [PMID: 36520314 DOI: 10.1007/978-3-031-14740-1_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Molecular chaperones and their associated co-chaperones are essential in health and disease as they are key facilitators of protein-folding, quality control and function. In particular, the heat-shock protein (HSP) 70 and HSP90 molecular chaperone networks have been associated with neurodegenerative diseases caused by aberrant protein-folding. The pathogenesis of these disorders usually includes the formation of deposits of misfolded, aggregated protein. HSP70 and HSP90, plus their co-chaperones, have been recognised as potent modulators of misfolded protein toxicity, inclusion formation and cell survival in cellular and animal models of neurodegenerative disease. Moreover, these chaperone machines function not only in folding but also in proteasome-mediated degradation of neurodegenerative disease proteins. This chapter gives an overview of the HSP70 and HSP90 chaperones, and their respective regulatory co-chaperones, and explores how the HSP70 and HSP90 chaperone systems form a larger functional network and its relevance to counteracting neurodegenerative disease associated with misfolded proteins and disruption of proteostasis.
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Affiliation(s)
| | - Xavi Aran-Guiu
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Jasmeen Oberoi
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Laura Perna
- Centre for Endocrinology, William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - J Paul Chapple
- Centre for Endocrinology, William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK.
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17
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Das A, Imanishi Y. Drug Discovery Strategies for Inherited Retinal Degenerations. BIOLOGY 2022; 11:1338. [PMID: 36138817 PMCID: PMC9495580 DOI: 10.3390/biology11091338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 12/03/2022]
Abstract
Inherited retinal degeneration is a group of blinding disorders afflicting more than 1 in 4000 worldwide. These disorders frequently cause the death of photoreceptor cells or retinal ganglion cells. In a subset of these disorders, photoreceptor cell death is a secondary consequence of retinal pigment epithelial cell dysfunction or degeneration. This manuscript reviews current efforts in identifying targets and developing small molecule-based therapies for these devastating neuronal degenerations, for which no cures exist. Photoreceptors and retinal ganglion cells are metabolically demanding owing to their unique structures and functional properties. Modulations of metabolic pathways, which are disrupted in most inherited retinal degenerations, serve as promising therapeutic strategies. In monogenic disorders, great insights were previously obtained regarding targets associated with the defective pathways, including phototransduction, visual cycle, and mitophagy. In addition to these target-based drug discoveries, we will discuss how phenotypic screening can be harnessed to discover beneficial molecules without prior knowledge of their mechanisms of action. Because of major anatomical and biological differences, it has frequently been challenging to model human inherited retinal degeneration conditions using small animals such as rodents. Recent advances in stem cell-based techniques are opening new avenues to obtain pure populations of human retinal ganglion cells and retinal organoids with photoreceptor cells. We will discuss concurrent ideas of utilizing stem-cell-based disease models for drug discovery and preclinical development.
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Affiliation(s)
- Arupratan Das
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yoshikazu Imanishi
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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18
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Leung A, Sacristan-Reviriego A, Perdigão PRL, Sai H, Georgiou M, Kalitzeos A, Carr AJF, Coffey PJ, Michaelides M, Bainbridge J, Cheetham ME, van der Spuy J. Investigation of PTC124-mediated translational readthrough in a retinal organoid model of AIPL1-associated Leber congenital amaurosis. Stem Cell Reports 2022; 17:2187-2202. [PMID: 36084639 PMCID: PMC9561542 DOI: 10.1016/j.stemcr.2022.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 10/26/2022] Open
Abstract
Leber congenital amaurosis type 4 (LCA4), caused by AIPL1 mutations, is characterized by severe sight impairment in infancy and rapidly progressing degeneration of photoreceptor cells. We generated retinal organoids using induced pluripotent stem cells (iPSCs) from renal epithelial cells obtained from four children with AIPL1 nonsense mutations. iPSC-derived photoreceptors exhibited the molecular hallmarks of LCA4, including undetectable AIPL1 and rod cyclic guanosine monophosphate (cGMP) phosphodiesterase (PDE6) compared with control or CRISPR-corrected organoids. Increased levels of cGMP were detected. The translational readthrough-inducing drug (TRID) PTC124 was investigated as a potential therapeutic agent. LCA4 retinal organoids exhibited low levels of rescue of full-length AIPL1. However, this was insufficient to fully restore PDE6 in photoreceptors and reduce cGMP. LCA4 retinal organoids are a valuable platform for in vitro investigation of novel therapeutic agents.
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Affiliation(s)
- Amy Leung
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | | | | | - Hali Sai
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | | | | | - Michel Michaelides
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - James Bainbridge
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
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19
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Ziaka K, van der Spuy J. The Role of Hsp90 in Retinal Proteostasis and Disease. Biomolecules 2022; 12:biom12070978. [PMID: 35883534 PMCID: PMC9313453 DOI: 10.3390/biom12070978] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/24/2022] Open
Abstract
Photoreceptors are sensitive neuronal cells with great metabolic demands, as they are responsible for carrying out visual phototransduction, a complex and multistep process that requires the exquisite coordination of a large number of signalling protein components. Therefore, the viability of photoreceptors relies on mechanisms that ensure a well-balanced and functional proteome that maintains the protein homeostasis, or proteostasis, of the cell. This review explores how the different isoforms of Hsp90, including the cytosolic Hsp90α/β, the mitochondrial TRAP1, and the ER-specific GRP94, are involved in the different proteostatic mechanisms of photoreceptors, and elaborates on Hsp90 function when retinal homeostasis is disturbed. In addition, several studies have shown that chemical manipulation of Hsp90 has significant consequences, both in healthy and degenerating retinae, and this can be partially attributed to the fact that Hsp90 interacts with important photoreceptor-associated client proteins. Here, the interaction of Hsp90 with the retina-specific client proteins PDE6 and GRK1 will be further discussed, providing additional insights for the role of Hsp90 in retinal disease.
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Matsuyama A, Kalargyrou AA, Smith AJ, Ali RR, Pearson RA. A comprehensive atlas of Aggrecan, Versican, Neurocan and Phosphacan expression across time in wildtype retina and in retinal degeneration. Sci Rep 2022; 12:7282. [PMID: 35508614 PMCID: PMC9068689 DOI: 10.1038/s41598-022-11204-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 04/07/2022] [Indexed: 11/08/2022] Open
Abstract
As photoreceptor cells die during retinal degeneration, the surrounding microenvironment undergoes significant changes that are increasingly recognized to play a prominent role in determining the efficacy of therapeutic interventions. Chondroitin Sulphate Proteoglycans (CSPGs) are a major component of the extracellular matrix that have been shown to inhibit neuronal regrowth and regeneration in the brain and spinal cord, but comparatively little is known about their expression in retinal degeneration. Here we provide a comprehensive atlas of the expression patterns of four individual CSPGs in three models of inherited retinal degeneration and wildtype mice. In wildtype mice, Aggrecan presented a biphasic expression, while Neurocan and Phosphacan expression declined dramatically with time and Versican expression remained broadly constant. In degeneration, Aggrecan expression increased markedly in Aipl1-/- and Pde6brd1/rd1, while Versican showed regional increases in the periphery of Rho-/- mice. Conversely, Neurocan and Phosphacan broadly decrease with time in all models. Our data reveal significant heterogeneity in the expression of individual CSPGs. Moreover, there are striking differences in the expression patterns of specific CSPGs in the diseased retina, compared with those reported following injury elsewhere in the CNS. Better understanding of the distinct distributions of individual CSPGs will contribute to creating more permissive microenvironments for neuro-regeneration and repair.
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Affiliation(s)
- A Matsuyama
- Ocular Cell and Gene therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, 8th Floor, Tower Wing, Guy's Hospital, London, SE1 9RT, UK.
- University College London Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK.
- RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama City, Kanagawa, 230-0045, Japan.
| | - A A Kalargyrou
- Ocular Cell and Gene therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, 8th Floor, Tower Wing, Guy's Hospital, London, SE1 9RT, UK
- University College London Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - A J Smith
- Ocular Cell and Gene therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, 8th Floor, Tower Wing, Guy's Hospital, London, SE1 9RT, UK
- University College London Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - R R Ali
- Ocular Cell and Gene therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, 8th Floor, Tower Wing, Guy's Hospital, London, SE1 9RT, UK
- University College London Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - R A Pearson
- Ocular Cell and Gene therapy Group, Centre for Gene Therapy and Regenerative Medicine, King's College London, 8th Floor, Tower Wing, Guy's Hospital, London, SE1 9RT, UK.
- University College London Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK.
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21
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Yadav RP, Boyd K, Artemyev NO. Molecular insights into the maturation of phosphodiesterase 6 by the specialized chaperone complex of HSP90 with AIPL1. J Biol Chem 2022; 298:101620. [PMID: 35065964 PMCID: PMC8857470 DOI: 10.1016/j.jbc.2022.101620] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/18/2022] Open
Abstract
Phosphodiesterase 6 (PDE6) is a key effector enzyme in vertebrate phototransduction, and its maturation and function are known to critically depend on a specialized chaperone, aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1). Defects in PDE6 and AIPL1 underlie several severe retinal diseases, including retinitis pigmentosa and Leber congenital amaurosis. Here, we characterize the complex of AIPL1 with HSP90 and demonstrate its essential role in promoting the functional conformation of nascent PDE6. Our analysis suggests that AIPL1 preferentially binds to HSP90 in the closed state with a stoichiometry of 1:2, with the tetratricopeptide repeat domain and the tetratricopeptide repeat helix 7 extension of AIPL1 being the main contributors to the AIPL1/HSP90 interface. We demonstrate that mutations of these determinants markedly diminished both the affinity of AIPL1 for HSP90 and the ability of AIPL1 to cochaperone the maturation of PDE6 in a heterologous expression system. In addition, the FK506-binding protein (FKBP) domain of AIPL1 encloses a unique prenyl-binding site that anchors AIPL1 to posttranslational lipid modifications of PDE6. A mouse model with rod PDE6 lacking farnesylation of its PDE6A subunit revealed normal expression, trafficking, and signaling of the enzyme. Furthermore, AIPL1 was unexpectedly capable of inducing the maturation of unprenylated cone PDE6C, whereas mutant AIPL1 deficient in prenyl binding competently cochaperoned prenylated PDE6C. Thus, we conclude neither sequestration of the prenyl modifications is required for PDE6 maturation to proceed, nor is the FKBP-lipid interaction involved in the conformational switch of the enzyme into the functional state.
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Affiliation(s)
- Ravi P Yadav
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Kimberly Boyd
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA; Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
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22
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Johnson JL. Mutations in Hsp90 Cochaperones Result in a Wide Variety of Human Disorders. Front Mol Biosci 2021; 8:787260. [PMID: 34957217 PMCID: PMC8694271 DOI: 10.3389/fmolb.2021.787260] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/08/2021] [Indexed: 12/19/2022] Open
Abstract
The Hsp90 molecular chaperone, along with a set of approximately 50 cochaperones, mediates the folding and activation of hundreds of cellular proteins in an ATP-dependent cycle. Cochaperones differ in how they interact with Hsp90 and their ability to modulate ATPase activity of Hsp90. Cochaperones often compete for the same binding site on Hsp90, and changes in levels of cochaperone expression that occur during neurodegeneration, cancer, or aging may result in altered Hsp90-cochaperone complexes and client activity. This review summarizes information about loss-of-function mutations of individual cochaperones and discusses the overall association of cochaperone alterations with a broad range of diseases. Cochaperone mutations result in ciliary or muscle defects, neurological development or degeneration disorders, and other disorders. In many cases, diseases were linked to defects in established cochaperone-client interactions. A better understanding of the functional consequences of defective cochaperones will provide new insights into their functions and may lead to specialized approaches to modulate Hsp90 functions and treat some of these human disorders.
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Affiliation(s)
- Jill L Johnson
- Department of Biological Sciences and Center for Reproductive Biology, University of Idaho, Moscow, ID, United States
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23
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Zhang X, Wang W, Jin ZB. Retinal organoids as models for development and diseases. CELL REGENERATION (LONDON, ENGLAND) 2021; 10:33. [PMID: 34719743 PMCID: PMC8557999 DOI: 10.1186/s13619-021-00097-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/22/2021] [Indexed: 12/12/2022]
Abstract
The evolution of pluripotent stem cell-derived retinal organoids (ROs) has brought remarkable opportunities for developmental studies while also presenting new therapeutic avenues for retinal diseases. With a clear understanding of how well these models mimic native retinas, such preclinical models may be crucial tools that are widely used for the more efficient translation of studies into novel treatment strategies for retinal diseases. Genetic modifications or patient-derived ROs can allow these models to simulate the physical microenvironments of the actual disease process. However, we are currently at the beginning of the three-dimensional (3D) RO era, and a general quantitative technology for analyzing ROs derived from numerous differentiation protocols is still missing. Continued efforts to improve the efficiency and stability of differentiation, as well as understanding the disparity between the artificial retina and the native retina and advancing the current treatment strategies, will be essential in ensuring that these scientific advances can benefit patients with retinal disease. Herein, we briefly discuss RO differentiation protocols, the current applications of RO as a disease model and the treatments for retinal diseases by using RO modeling, to have a clear view of the role of current ROs in retinal development and diseases.
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Affiliation(s)
- Xiao Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Wen Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
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24
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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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25
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New In Vitro Cellular Model for Molecular Studies of Retinitis Pigmentosa. Int J Mol Sci 2021; 22:ijms22126440. [PMID: 34208617 PMCID: PMC8235468 DOI: 10.3390/ijms22126440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/04/2021] [Accepted: 06/13/2021] [Indexed: 02/05/2023] Open
Abstract
Retinitis pigmentosa (RP) is an inherited form of retinal degeneration characterized by primary rod photoreceptor cell death followed by cone loss. Mutations in several genes linked to the disease cause increased levels of cyclic guanosine monophosphate (cGMP) and calcium ion influxes. The purpose of this project was to develop a new in vitro photoreceptor degeneration model for molecular studies of RP. 661W cells were genetically modified to stably express the neural retina leucine zipper (NRL) transcription factor. One clone (661W-A11) was selected based on the expression of Nrl target genes. 661W-A11 showed a significant increase in expression of rod-specific genes but not of cone-specific genes, compared with 661W cells. Zaprinast was used to inhibit phosphodiesterase 6 (PDE6) activity to mimic photoreceptor degeneration in vitro. The activation of cell death pathways resulting from PDE6 inhibition was confirmed by detection of decreased viability and increased intracellular cGMP and calcium, as well as activation of protein kinase G (PKG) and calpains. In this new in vitro system, we validated the effects of previously published neuroprotective drugs. The 661W-A11 cells may serve as a new model for molecular studies of RP and for high-throughput drug screening.
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26
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Bisbach CM, Hass DT, Robbings BM, Rountree AM, Sadilek M, Sweet IR, Hurley JB. Succinate Can Shuttle Reducing Power from the Hypoxic Retina to the O 2-Rich Pigment Epithelium. Cell Rep 2021; 31:107606. [PMID: 32375026 DOI: 10.1016/j.celrep.2020.107606] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/21/2020] [Accepted: 04/10/2020] [Indexed: 12/19/2022] Open
Abstract
When O2 is plentiful, the mitochondrial electron transport chain uses it as a terminal electron acceptor. However, the mammalian retina thrives in a hypoxic niche in the eye. We find that mitochondria in retinas adapt to their hypoxic environment by reversing the succinate dehydrogenase reaction to use fumarate to accept electrons instead of O2. Reverse succinate dehydrogenase activity produces succinate and is enhanced by hypoxia-induced downregulation of cytochrome oxidase. Retinas can export the succinate they produce to the neighboring O2-rich retinal pigment epithelium-choroid complex. There, succinate enhances O2 consumption by severalfold. Malate made from succinate in the pigment epithelium can then be imported into the retina, where it is converted to fumarate to again accept electrons in the reverse succinate dehydrogenase reaction. This malate-succinate shuttle can sustain these two tissues by transferring reducing power from an O2-poor tissue (retina) to an O2-rich one (retinal pigment epithelium-choroid).
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Affiliation(s)
- Celia M Bisbach
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Daniel T Hass
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Brian M Robbings
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; UW Diabetes Institute, University of Washington, Seattle, WA 98195, USA
| | - Austin M Rountree
- UW Diabetes Institute, University of Washington, Seattle, WA 98195, USA
| | - Martin Sadilek
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Ian R Sweet
- UW Diabetes Institute, University of Washington, Seattle, WA 98195, USA
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA.
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27
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Jiang K, Fairless E, Kanda A, Gotoh N, Cogliati T, Li T, Swaroop A. Divergent Effects of HSP70 Overexpression in Photoreceptors During Inherited Retinal Degeneration. Invest Ophthalmol Vis Sci 2021; 61:25. [PMID: 33107904 PMCID: PMC7594617 DOI: 10.1167/iovs.61.12.25] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Purpose Disruption of proteostasis is a key event in many neurodegenerative diseases. Heat shock proteins (HSPs) participate in multiple functions associated with intracellular transport and proteostasis. We evaluated the effect of augmented HSP70 expression in mutant photoreceptors of mouse retinal degeneration models to test the hypothesis that failure to sustain HSP70 expression contributes to photoreceptor cell death. Methods We examined HSP70 expression in retinas of wild-type and mutant mice by RNA and protein analysis. A transgenic mouse line, TgCrx-Hspa1a-Flag, was generated to express FLAG-tagged full-length HSP70 protein under control of a 2.3 kb mouse Crx promoter. This line was crossed to three distinct retinal degeneration mouse models. Retinal structure and function were evaluated by histology, immunohistochemistry, and electroretinography. Results In seven different mouse models of retinal degeneration, we detected transient elevation of endogenous HSP70 expression at early stages, followed by a dramatic reduction as cell death ensues, suggesting an initial adaptive response to cellular stress. Augmented expression of HSP70 in RHOT17M mice, in which mutant rhodopsin is misfolded, marginally improved photoreceptor survival, whereas elevated HSP70 led to more severe retinal degeneration in rd10 mutants that produce a partially functional PDE6B. In Rpgrip1−/− mice that display a ciliary defect, higher HSP70 had no impact on photoreceptor survival or function. Conclusions HSP70 overexpression has divergent effects in photoreceptors determined, at least in part, by the nature of the mutant protein each model carries. Additional investigations on HSP pathways and associated chaperone networks in photoreceptors are needed before designing therapeutic strategies targeting proteostasis.
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Affiliation(s)
- Ke Jiang
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Elizabeth Fairless
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Atsuhiro Kanda
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Norimoto Gotoh
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Tiziana Cogliati
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Tiansen Li
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Anand Swaroop
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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28
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Daich Varela M, Ullah E, Yousaf S, Brooks BP, Hufnagel RB, Huryn LA. PDE6C: Novel Mutations, Atypical Phenotype, and Differences Among Children and Adults. Invest Ophthalmol Vis Sci 2021; 61:1. [PMID: 33001157 PMCID: PMC7545085 DOI: 10.1167/iovs.61.12.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Purpose Genetic variation in PDE6C is associated with achromatopsia and cone dystrophy, with only a few reports of cone-rod dystrophy in the literature. We describe two pediatric and two adult patients with PDE6C related cone and cone-rod dystrophy and the first longitudinal data of a pediatric patient with PDE6C-related cone dystrophy. Methods This cohort of four patients underwent comprehensive ophthalmologic evaluation at the National Eye Institute's Ophthalmic Genetics clinic, including visual field testing, retinal imaging and electroretinogram (ERG). Next-generation sequencing-based genetic testing was performed and subsequent analysis of the variants was done through three-dimensional protein models generated by Phyre2 and Chimera. Results All cases shared decreased best-corrected visual acuity and poor color discrimination. Three of the four patients had a cone-rod dystrophy, presenting with an ERG showing decreased amplitude on both photopic and scotopic waveforms and a mild to moderately constricted visual field. One of the children was diagnosed with cone dystrophy, having a preserved peripheral field. The children had none to minor structural retinal changes, whereas the adults had clear macular dystrophy. Conclusions PDE6C-related cone-rod dystrophy consists of a severe phenotype characterized by early-onset nystagmus, decreased best-corrected visual acuity, poor color discrimination, progressive constriction of the visual field, and night blindness. Our work contributes with valuable information toward understanding the visual prognosis and allelic heterogeneity of PDE6C-related cone and cone-rod dystrophy.
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Affiliation(s)
- Malena Daich Varela
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Ehsan Ullah
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Sairah Yousaf
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Laryssa A Huryn
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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29
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Das S, Chen Y, Yan J, Christensen G, Belhadj S, Tolone A, Paquet-Durand F. The role of cGMP-signalling and calcium-signalling in photoreceptor cell death: perspectives for therapy development. Pflugers Arch 2021; 473:1411-1421. [PMID: 33864120 PMCID: PMC8370896 DOI: 10.1007/s00424-021-02556-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 12/12/2022]
Abstract
The second messengers, cGMP and Ca2+, have both been implicated in retinal degeneration; however, it is still unclear which of the two is most relevant for photoreceptor cell death. This problem is exacerbated by the close connections and crosstalk between cGMP-signalling and calcium (Ca2+)-signalling in photoreceptors. In this review, we summarize key aspects of cGMP-signalling and Ca2+-signalling relevant for hereditary photoreceptor degeneration. The topics covered include cGMP-signalling targets, the role of Ca2+ permeable channels, relation to energy metabolism, calpain-type proteases, and how the related metabolic processes may trigger and execute photoreceptor cell death. A focus is then put on cGMP-dependent mechanisms and how exceedingly high photoreceptor cGMP levels set in motion cascades of Ca2+-dependent and independent processes that eventually bring about photoreceptor cell death. Finally, an outlook is given into mutation-independent therapeutic approaches that exploit specific features of cGMP-signalling. Such approaches might be combined with suitable drug delivery systems for translation into clinical applications.
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Affiliation(s)
- Soumyaparna Das
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - Yiyi Chen
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - Jie Yan
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - Gustav Christensen
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - Soumaya Belhadj
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - Arianna Tolone
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - François Paquet-Durand
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany.
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30
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Yang P, Lockard R, Titus H, Hiblar J, Weller K, Wafai D, Weleber RG, Duvoisin RM, Morgans CW, Pennesi ME. Suppression of cGMP-Dependent Photoreceptor Cytotoxicity With Mycophenolate Is Neuroprotective in Murine Models of Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2021; 61:25. [PMID: 32785677 PMCID: PMC7441375 DOI: 10.1167/iovs.61.10.25] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Purpose To determine the effect of mycophenolate mofetil (MMF) on retinal degeneration on two mouse models of retinitis pigmentosa. Methods Intraperitoneal injections of MMF were administered daily in rd10 and c57 mice starting at postoperative day 12 (P12) and rd1 mice starting at P8. The effect of MMF was assessed with optical coherence tomography, immunohistochemistry, electroretinography, and OptoMotry. Whole retinal cyclic guanosine monophosphate (cGMP) and mycophenolic acid levels were quantified with mass spectrometry. Photoreceptor cGMP cytotoxicity was evaluated with cell counts of cGMP immunostaining. Results MMF treatment significantly delays the onset of retinal degeneration and cGMP-dependent photoreceptor cytotoxicity in rd10 and rd1 mice, albeit a more modest effect in the latter. In rd10 mice, treatment with MMF showed robust preservation of the photoreceptors up to P22 with associated suppression of cGMP immunostaining and microglial activation; The neuroprotective effect diminished after P22, but outer retinal thickness was still significantly thicker by P35 and OptoMotry response was significantly better up to P60. Whereas cGMP immunostaining of the photoreceptors were present in rd10 and rd1 mice, hyperphysiological whole retinal cGMP levels were observed only in rd1 mice. Conclusions Early treatment with MMF confers potent neuroprotection in two animal models of RP by suppressing the cGMP-dependent common pathway for photoreceptor cell death. The neuroprotective effect of MMF on cGMP-dependent cytotoxicity occurs independently of the presence of hyperphysiological whole retinal cGMP levels. Thus our data suggest that MMF may be an important new class of neuroprotective agent that could be useful in the treatment of patients with RP.
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Affiliation(s)
- Paul Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Rachel Lockard
- School of Medicine, Oregon Health & Science University, Portland, Oregon, United States
| | - Hope Titus
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Jordan Hiblar
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Kyle Weller
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Dahlia Wafai
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Robert M Duvoisin
- Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Catherine W Morgans
- Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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31
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Sacristan-Reviriego A, Le HM, Georgiou M, Meunier I, Bocquet B, Roux AF, Prodromou C, Bainbridge J, Michaelides M, van der Spuy J. Clinical and functional analyses of AIPL1 variants reveal mechanisms of pathogenicity linked to different forms of retinal degeneration. Sci Rep 2020; 10:17520. [PMID: 33067476 PMCID: PMC7567831 DOI: 10.1038/s41598-020-74516-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/21/2020] [Indexed: 12/18/2022] Open
Abstract
Disease-causing sequence variants in the highly polymorphic AIPL1 gene are associated with a broad spectrum of inherited retinal diseases ranging from severe autosomal recessive Leber congenital amaurosis to later onset retinitis pigmentosa. AIPL1 is a photoreceptor-specific co-chaperone that interacts with HSP90 to facilitate the stable assembly of retinal cGMP phosphodiesterase, PDE6. In this report, we establish unequivocal correlations between patient clinical phenotypes and in vitro functional assays of uncharacterized AIPL1 variants. We confirm that missense and nonsense variants in the FKBP-like and tetratricopeptide repeat domains of AIPL1 lead to the loss of both HSP90 interaction and PDE6 activity, confirming these variants cause LCA. In contrast, we report the association of p.G122R with milder forms of retinal degeneration, and show that while p.G122R had no effect on HSP90 binding, the modulation of PDE6 cGMP levels was impaired. The clinical history of these patients together with our functional assays suggest that the p.G122R variant is a rare hypomorphic allele with a later disease onset, amenable to therapeutic intervention. Finally, we report the primate-specific proline-rich domain to be dispensable for both HSP90 interaction and PDE6 activity. We conclude that variants investigated in this domain do not cause disease, with the exception of p.A352_P355del associated with autosomal dominant cone-rod dystrophy.
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Affiliation(s)
| | - Hoang Mai Le
- UCL Institute of Ophthalmology, University College London, 11 - 43 Bath Street, London, EC1V 9EL, UK
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, 11 - 43 Bath Street, London, EC1V 9EL, UK.,Moorfields Eye Hospital, City Road, London, EC1V 2PD, UK
| | - Isabelle Meunier
- Centre National de Référence Maladies Sensorielles Génétiques, Service Ophtalmologie Hôpital Gui de Chauliac - CHRU de Montpellier, 80 rue Augustin Fliche, 34295, Montpellier, France
| | - Beatrice Bocquet
- Centre National de Référence Maladies Sensorielles Génétiques, Service Ophtalmologie Hôpital Gui de Chauliac - CHRU de Montpellier, 80 rue Augustin Fliche, 34295, Montpellier, France
| | - Anne-Françoise Roux
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | | | - James Bainbridge
- UCL Institute of Ophthalmology, University College London, 11 - 43 Bath Street, London, EC1V 9EL, UK.,Moorfields Eye Hospital, City Road, London, EC1V 2PD, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, 11 - 43 Bath Street, London, EC1V 9EL, UK.,Moorfields Eye Hospital, City Road, London, EC1V 2PD, UK
| | - Jacqueline van der Spuy
- UCL Institute of Ophthalmology, University College London, 11 - 43 Bath Street, London, EC1V 9EL, UK.
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32
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Sallum JMF, Motta FL, Arno G, Porto FBO, Resende RG, Belfort R. Clinical and molecular findings in a cohort of 152 Brazilian severe early onset inherited retinal dystrophy patients. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:728-752. [PMID: 32865313 DOI: 10.1002/ajmg.c.31828] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/25/2020] [Accepted: 07/28/2020] [Indexed: 12/17/2022]
Abstract
Leber congenital amaurosis (LCA) and early-onset retinal dystrophy (EORD) are severe inherited retinal dystrophy that can cause deep blindness childhood. They represent 5% of all retinal dystrophies in the world population and about 10% in Brazil. Clinical findings and molecular basis of syndromic and nonsyndromic LCA/EORD in a Brazilian sample (152 patients/137 families) were studied. In this population, 15 genes were found to be related to the phenotype, 38 new variants were detected and four new complex alleles were discovered. Among 123 variants found, the most common were CEP290: c.2991+1655A>G, CRB1: p.Cys948Tyr, and RPGRIP1: exon10-18 deletion.
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Affiliation(s)
- Juliana Maria Ferraz Sallum
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil.,Instituto de Genética Ocular, Sao Paulo, Brazil
| | - Fabiana Louise Motta
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil.,Instituto de Genética Ocular, Sao Paulo, Brazil
| | - Gavin Arno
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | - Fernanda Belga Ottoni Porto
- INRET Clínica e Centro de Pesquisa, Belo Horizonte, Minas Gerais, Brazil.,Centro Oftalmológico de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Rubens Belfort
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil
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33
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Boehm AN, Bialas J, Catone N, Sacristan-Reviriego A, van der Spuy J, Groettrup M, Aichem A. The ubiquitin-like modifier FAT10 inhibits retinal PDE6 activity and mediates its proteasomal degradation. J Biol Chem 2020; 295:14402-14418. [PMID: 32817338 DOI: 10.1074/jbc.ra120.013873] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/12/2020] [Indexed: 11/06/2022] Open
Abstract
The retina-specific chaperone aryl hydrocarbon interacting protein-like 1 (AIPL1) is essential for the correct assembly of phosphodiesterase 6 (PDE6), which is a pivotal effector enzyme for phototransduction and vision because it hydrolyzes cGMP. AIPL1 interacts with the cytokine-inducible ubiquitin-like modifier FAT10, which gets covalently conjugated to hundreds of proteins and targets its conjugation substrates for proteasomal degradation, but whether FAT10 affects PDE6 function or turnover is unknown. Here, we show that FAT10 mRNA is expressed in human retina and identify rod PDE6 as a retina-specific substrate of FAT10 conjugation. We found that AIPL1 stabilizes the FAT10 monomer and the PDE6-FAT10 conjugate. Additionally, we elucidated the functional consequences of PDE6 FAT10ylation. On the one hand, we demonstrate that FAT10 targets PDE6 for proteasomal degradation by formation of a covalent isopeptide linkage. On the other hand, FAT10 inhibits PDE6 cGMP hydrolyzing activity by noncovalently interacting with the PDE6 GAFa and catalytic domains. Therefore, FAT10 may contribute to loss of PDE6 and, as a consequence, degeneration of retinal cells in eye diseases linked to inflammation and inherited blindness-causing mutations in AIPL1.
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Affiliation(s)
- Annika N Boehm
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany.,Biotechnology Institute Thurgau at the University of Konstanz, Kreuzlingen, Switzerland
| | - Johanna Bialas
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany.,Biotechnology Institute Thurgau at the University of Konstanz, Kreuzlingen, Switzerland
| | - Nicola Catone
- Biotechnology Institute Thurgau at the University of Konstanz, Kreuzlingen, Switzerland
| | | | | | - Marcus Groettrup
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany.,Biotechnology Institute Thurgau at the University of Konstanz, Kreuzlingen, Switzerland
| | - Annette Aichem
- Division of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany .,Biotechnology Institute Thurgau at the University of Konstanz, Kreuzlingen, Switzerland
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34
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West EL, Ribeiro J, Ali RR. Development of Stem Cell Therapies for Retinal Degeneration. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035683. [PMID: 31818854 DOI: 10.1101/cshperspect.a035683] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Degenerative retinal disease is the major cause of sight loss in the developed world and currently there is a lack of effective treatments. As the loss of vision is directly the result of the loss of retinal cells, effective cell replacement through stem-cell-based therapies may have the potential to treat a great number of retinal diseases whatever their underlying etiology. The eye is an ideal organ to develop cell therapies as it is immune privileged, and modern surgical techniques enable precise delivery of cells to the retina. Furthermore, a range of noninvasive diagnostic tests and high-resolution imaging techniques facilitate the evaluation of any therapeutic intervention. In this review, we evaluate the progress to date of current cell therapy strategies for retinal repair, focusing on transplantation of pluripotent stem-cell-derived retinal pigment epithelium (RPE) and photoreceptor cells.
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Affiliation(s)
- Emma L West
- Division of Molecular Therapy, UCL Institute of Ophthalmology, London EC1V 9EL, United Kingdom
| | - Joana Ribeiro
- Division of Molecular Therapy, UCL Institute of Ophthalmology, London EC1V 9EL, United Kingdom
| | - Robin R Ali
- Division of Molecular Therapy, UCL Institute of Ophthalmology, London EC1V 9EL, United Kingdom.,Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan 48105, USA
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35
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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:E931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [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.)
| | - 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.)
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36
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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: 51] [Impact Index Per Article: 10.2] [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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37
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Retinal Organoids derived from hiPSCs of an AIPL1-LCA Patient Maintain Cytoarchitecture despite Reduced levels of Mutant AIPL1. Sci Rep 2020; 10:5426. [PMID: 32214115 PMCID: PMC7096529 DOI: 10.1038/s41598-020-62047-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 03/02/2020] [Indexed: 12/22/2022] Open
Abstract
Aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) is a photoreceptor-specific chaperone that stabilizes the effector enzyme of phototransduction, cGMP phosphodiesterase 6 (PDE6). Mutations in the AIPL1 gene cause a severe inherited retinal dystrophy, Leber congenital amaurosis type 4 (LCA4), that manifests as the loss of vision during the first year of life. In this study, we generated three-dimensional (3D) retinal organoids (ROs) from human induced pluripotent stem cells (hiPSCs) derived from an LCA4 patient carrying a Cys89Arg mutation in AIPL1. This study aimed to (i) explore whether the patient hiPSC-derived ROs recapitulate LCA4 disease phenotype, and (ii) generate a clinically relevant resource to investigate the molecular mechanism of disease and safely test novel therapies for LCA4 in vitro. We demonstrate reduced levels of the mutant AIPL1 and PDE6 proteins in patient organoids, corroborating the findings in animal models; however, patient-derived organoids maintained retinal cell cytoarchitecture despite significantly reduced levels of AIPL1.
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38
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Yang P, Lockard RA, Titus H. Techniques to Quantify cGMP Dysregulation as a Common Pathway Associated with Photoreceptor Cell Death in Retinitis Pigmentosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:407-411. [PMID: 31884646 DOI: 10.1007/978-3-030-27378-1_67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The targeted development of neuroprotective therapies for retinitis pigmentosa (RP) depends upon a better understanding of the mechanisms of photoreceptor cell death. Nucleotide metabolite-associated photoreceptor cell death is an emerging area of research that is important in multiple models of RP, yet the exact pathophysiology remains to be elucidated. One common pathway of photoreceptor cell death in RP is cGMP dysregulation, which is underscored by its potential to be relevant in up to 30% of patients with RP. Optimizing tools for detecting and quantifying nucleotide metabolites in the retina is vital to expanding this area of research. Immunohistochemistry is useful for localizing abnormally high levels of cGMP in a cell-specific manner, while enzyme-linked immunosorbent assay and liquid chromatography-mass spectrometry are quantitative and more sensitive. These techniques can form the basis for more sophisticated experiments to elucidate upstream events in photoreceptor cell death, which will hopefully lead to the development of novel therapies for patients with RP.
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Affiliation(s)
- Paul Yang
- Casey Eye Institute, Orgeon Health and Science University, Portland, OR, USA.
| | - Rachel A Lockard
- Casey Eye Institute, Orgeon Health and Science University, Portland, OR, USA
| | - Hope Titus
- Casey Eye Institute, Orgeon Health and Science University, Portland, OR, USA
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39
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RD Genes Associated with High Photoreceptor cGMP-Levels (Mini-Review). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:245-249. [PMID: 31884619 DOI: 10.1007/978-3-030-27378-1_40] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Many RD-causing mutations lead to a dysregulation of cyclic guanosine monophosphate (cGMP), making cGMP signalling a prime target for the development of new treatment approaches. We showed previously that an analogue of cGMP, which inhibited cGMP signalling targets, increased photoreceptor viability in three rodent RD models carrying different genetic defects, in different RD genes. This raises the question of the possible generality of this approach as a treatment for RD. Here, we review RD genes that can be associated with high cGMP and discuss which RD genes might be amenable to a treatment aimed at inhibiting excessive cGMP signalling.
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40
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Karali M, Guadagnino I, Marrocco E, De Cegli R, Carissimo A, Pizzo M, Casarosa S, Conte I, Surace EM, Banfi S. AAV-miR-204 Protects from Retinal Degeneration by Attenuation of Microglia Activation and Photoreceptor Cell Death. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 19:144-156. [PMID: 31837604 PMCID: PMC6920266 DOI: 10.1016/j.omtn.2019.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/07/2019] [Accepted: 11/07/2019] [Indexed: 01/15/2023]
Abstract
Inherited retinal diseases (IRDs) represent a frequent cause of genetic blindness. Their high genetic heterogeneity hinders the application of gene-specific therapies to the vast majority of patients. We recently demonstrated that the microRNA miR-204 is essential for retinal function, although the underlying molecular mechanisms remain poorly understood. Here, we investigated the therapeutic potential of miR-204 in IRDs. We subretinally delivered an adeno-associated viral (AAV) vector carrying the miR-204 precursor to two genetically different IRD mouse models. The administration of AAV-miR-204 preserved retinal function in a mouse model for a dominant form of retinitis pigmentosa (RHO-P347S). This was associated with a reduction of apoptotic photoreceptor cells and with a better preservation of photoreceptor marker expression. Transcriptome analysis showed that miR-204 shifts expression profiles of transgenic retinas toward those of healthy retinas by the downregulation of microglia activation and photoreceptor cell death. Delivery of miR-204 exerted neuroprotective effects also in a mouse model of Leber congenital amaurosis, due to mutations of the Aipl1 gene. Our study highlights the mutation-independent therapeutic potential of AAV-miR204 in slowing down retinal degeneration in IRDs and unveils the previously unreported role of this miRNA in attenuating microglia activation and photoreceptor cell death.
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Affiliation(s)
- Marianthi Karali
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy; Department of Precision Medicine, University of Campania 'Luigi Vanvitelli,' via Luigi De Crecchio 7, 80138 Naples (NA), Italy
| | - Irene Guadagnino
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Elena Marrocco
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Rossella De Cegli
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Annamaria Carissimo
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Mariateresa Pizzo
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Simona Casarosa
- Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy; CNR Neuroscience Institute, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Enrico Maria Surace
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy; Department of Translational Medicine, 'Federico II' University, via Pansini 5, 80131 Naples, Italy.
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy; Department of Precision Medicine, University of Campania 'Luigi Vanvitelli,' via Luigi De Crecchio 7, 80138 Naples (NA), Italy.
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41
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Yadav RP, Boyd K, Yu L, Artemyev NO. Interaction of the tetratricopeptide repeat domain of aryl hydrocarbon receptor-interacting protein-like 1 with the regulatory Pγ subunit of phosphodiesterase 6. J Biol Chem 2019; 294:15795-15807. [PMID: 31488544 DOI: 10.1074/jbc.ra119.010666] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/03/2019] [Indexed: 12/13/2022] Open
Abstract
Phosphodiesterase-6 (PDE6) is key to both phototransduction and health of rods and cones. Proper folding of PDE6 relies on the chaperone activity of aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1), and mutations in both PDE6 and AIPL1 can cause a severe form of blindness. Although AIPL1 and PDE6 are known to interact via the FK506-binding protein domain of AIPL1, the contribution of the tetratricopeptide repeat (TPR) domain of AIPL1 to its chaperone function is poorly understood. Here, we demonstrate that AIPL1-TPR interacts specifically with the regulatory Pγ subunit of PDE6. Use of NMR chemical shift perturbation (CSP) mapping technique revealed the interface between the C-terminal portion of Pγ and AIPL1-TPR. Our solution of the crystal structure of the AIPL1-TPR domain provided additional information, which together with the CSP data enabled us to generate a model of this interface. Biochemical analysis of chimeric AIPL1-AIP proteins supported this model and also revealed a correlation between the affinity of AIPL1-TPR for Pγ and the ability of Pγ to potentiate the chaperone activity of AIPL1. Based on these results, we present a model of the larger AIPL1-PDE6 complex. This supports the importance of simultaneous interactions of AIPL1-FK506-binding protein with the prenyl moieties of PDE6 and AIPL1-TPR with the Pγ subunit during the folding and/or assembly of PDE6. This study sheds new light on the versatility of TPR domains in protein folding by describing a novel TPR-protein binding partner, Pγ, and revealing that this subunit imparts AIPL1 selectivity for its client.
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Affiliation(s)
- Ravi P Yadav
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Kimberly Boyd
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Liping Yu
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242.,NMR Core Facility, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242 .,Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
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42
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Power M, Das S, Schütze K, Marigo V, Ekström P, Paquet-Durand F. Cellular mechanisms of hereditary photoreceptor degeneration - Focus on cGMP. Prog Retin Eye Res 2019; 74:100772. [PMID: 31374251 DOI: 10.1016/j.preteyeres.2019.07.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/25/2019] [Accepted: 07/29/2019] [Indexed: 12/21/2022]
Abstract
The cellular mechanisms underlying hereditary photoreceptor degeneration are still poorly understood, a problem that is exacerbated by the enormous genetic heterogeneity of this disease group. However, the last decade has yielded a wealth of new knowledge on degenerative pathways and their diversity. Notably, a central role of cGMP-signalling has surfaced for photoreceptor cell death triggered by a subset of disease-causing mutations. In this review, we examine key aspects relevant for photoreceptor degeneration of hereditary origin. The topics covered include energy metabolism, epigenetics, protein quality control, as well as cGMP- and Ca2+-signalling, and how the related molecular and metabolic processes may trigger photoreceptor demise. We compare and integrate evidence on different cell death mechanisms that have been associated with photoreceptor degeneration, including apoptosis, necrosis, necroptosis, and PARthanatos. A special focus is then put on the mechanisms of cGMP-dependent cell death and how exceedingly high photoreceptor cGMP levels may cause activation of Ca2+-dependent calpain-type proteases, histone deacetylases and poly-ADP-ribose polymerase. An evaluation of the available literature reveals that a large group of patients suffering from hereditary photoreceptor degeneration carry mutations that are likely to trigger cGMP-dependent cell death, making this pathway a prime target for future therapy development. Finally, an outlook is given into technological and methodological developments that will with time likely contribute to a comprehensive overview over the entire metabolic complexity of photoreceptor cell death. Building on such developments, new imaging technology and novel biomarkers may be used to develop clinical test strategies, that fully consider the genetic heterogeneity of hereditary retinal degenerations, in order to facilitate clinical testing of novel treatment approaches.
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Affiliation(s)
- Michael Power
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Germany; Centre for Integrative Neurosciences (CIN), University of Tübingen, Germany; Graduate Training Centre of Neuroscience (GTC), University of Tübingen, Germany
| | - Soumyaparna Das
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Germany; Graduate Training Centre of Neuroscience (GTC), University of Tübingen, Germany
| | | | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | - Per Ekström
- Ophthalmology, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sweden
| | - François Paquet-Durand
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Germany.
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43
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Balancing the Photoreceptor Proteome: Proteostasis Network Therapeutics for Inherited Retinal Disease. Genes (Basel) 2019; 10:genes10080557. [PMID: 31344897 PMCID: PMC6722924 DOI: 10.3390/genes10080557] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022] Open
Abstract
The light sensing outer segments of photoreceptors (PRs) are renewed every ten days due to their high photoactivity, especially of the cones during daytime vision. This demands a tremendous amount of energy, as well as a high turnover of their main biosynthetic compounds, membranes, and proteins. Therefore, a refined proteostasis network (PN), regulating the protein balance, is crucial for PR viability. In many inherited retinal diseases (IRDs) this balance is disrupted leading to protein accumulation in the inner segment and eventually the death of PRs. Various studies have been focusing on therapeutically targeting the different branches of the PR PN to restore the protein balance and ultimately to treat inherited blindness. This review first describes the different branches of the PN in detail. Subsequently, insights are provided on how therapeutic compounds directed against the different PN branches might slow down or even arrest the appalling, progressive blinding conditions. These insights are supported by findings of PN modulators in other research disciplines.
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Photoreceptor cell replacement in macular degeneration and retinitis pigmentosa: A pluripotent stem cell-based approach. Prog Retin Eye Res 2019; 71:1-25. [DOI: 10.1016/j.preteyeres.2019.03.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/01/2019] [Accepted: 03/12/2019] [Indexed: 02/07/2023]
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45
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Tolone A, Belhadj S, Rentsch A, Schwede F, Paquet-Durand F. The cGMP Pathway and Inherited Photoreceptor Degeneration: Targets, Compounds, and Biomarkers. Genes (Basel) 2019; 10:genes10060453. [PMID: 31207907 PMCID: PMC6627777 DOI: 10.3390/genes10060453] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/05/2019] [Accepted: 06/11/2019] [Indexed: 12/17/2022] Open
Abstract
Photoreceptor physiology and pathophysiology is intricately linked to guanosine-3’,5’-cyclic monophosphate (cGMP)-signaling. Here, we discuss the importance of cGMP-signaling for the pathogenesis of hereditary retinal degeneration. Excessive accumulation of cGMP in photoreceptors is a common denominator in cell death caused by a variety of different gene mutations. The cGMP-dependent cell death pathway may be targeted for the treatment of inherited photoreceptor degeneration, using specifically designed and formulated inhibitory cGMP analogues. Moreover, cGMP-signaling and its down-stream targets may be exploited for the development of novel biomarkers that could facilitate monitoring of disease progression and reveal the response to treatment in future clinical trials. We then briefly present the importance of appropriate formulations for delivery to the retina, both for drug and biomarker applications. Finally, the review touches on important aspects of future clinical translation, highlighting the need for interdisciplinary cooperation of researchers from a diverse range of fields.
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Affiliation(s)
- Arianna Tolone
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 5-7, 72076 Tübingen, Germany.
| | - Soumaya Belhadj
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 5-7, 72076 Tübingen, Germany.
| | | | - Frank Schwede
- Biolog Life Science Institute, 28199 Bremen, Germany.
| | - François Paquet-Durand
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 5-7, 72076 Tübingen, Germany.
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46
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The Leber Congenital Amaurosis-Linked Protein AIPL1 and Its Critical Role in Photoreceptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1074:381-386. [PMID: 29721967 DOI: 10.1007/978-3-319-75402-4_47] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Mutations in the photoreceptor/pineal-expressed gene, aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1), are mainly associated with autosomal recessive Leber congenital amaurosis (LCA), the most severe form of inherited retinopathy that occurs in early childhood. AIPL1 functions as a photoreceptor-specific molecular co-chaperone that interacts specifically with the molecular chaperones HSP90 and HSP70 to facilitate the correct folding and assembly of the retinal cGMP phosphodiesterase (PDE6) holoenzyme. The absence of AIPL1 leads to a dramatic degeneration of rod and cone cells and a complete loss of any light-dependent electrical response. Here we review the important role of AIPL1 in photoreceptor functionality.
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47
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Du J, An J, Linton JD, Wang Y, Hurley JB. How Excessive cGMP Impacts Metabolic Proteins in Retinas at the Onset of Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1074:289-295. [PMID: 29721955 DOI: 10.1007/978-3-319-75402-4_35] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aryl-hydrocarbon receptor interacting protein-like 1 (AIPL1) is essential to stabilize cGMP phosphodiesterase 6 (PDE6) in rod photoreceptors. Mutation of AIPL1 leads to loss of PDE6, accumulation of intracellular cGMP, and rapid degeneration of rods. To understand the metabolic basis for the photoreceptor degeneration caused by excessive cGMP, we performed proteomics and phosphoproteomics analyses on retinas from AIPL1-/- mice at the onset of rod cell death. AIPL1-/- retinas have about 18 times less than normal PDE6a and no detectable PDE6b. We identified twelve other proteins and thirty-nine phosphorylated proteins related to cell metabolism that are significantly altered preceding the massive degeneration of rods. They include transporters, kinases, phosphatases, transferases, and proteins involved in mitochondrial bioenergetics and metabolism of glucose, lipids, amino acids, nucleotides, and RNA. In AIPLI-/- retinas mTOR and proteins involved in mitochondrial energy production and lipid synthesis are more dephosphorylated, but glycolysis proteins and proteins involved in leucine catabolism are more phosphorylated than in normal retinas. Our findings indicate that elevating cGMP rewires cellular metabolism prior to photoreceptor degeneration and that targeting metabolism may be a productive strategy to prevent or slow retinal degeneration.
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Affiliation(s)
- Jianhai Du
- Departments of Ophthalmology, and Biochemistry, West Virginia University, Morgantown, WV, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Jie An
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Jonathan D Linton
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Yekai Wang
- Departments of Ophthalmology, and Biochemistry, West Virginia University, Morgantown, WV, USA
| | - James B Hurley
- Department of Ophthalmology, University of Washington, Seattle, WA, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
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48
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Yu L, Yadav RP, Artemyev NO. NMR resonance assignments of the TPR domain of human aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1). BIOMOLECULAR NMR ASSIGNMENTS 2019; 13:79-83. [PMID: 30341566 PMCID: PMC6440825 DOI: 10.1007/s12104-018-9856-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 10/14/2018] [Indexed: 06/08/2023]
Abstract
Aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) is a photoreceptor-specific chaperone of phosphodiesterase-6, a key effector enzyme in the phototransduction cascade. It contains an N-terminal FK506-binding protein (FKBP) domain and a C-terminal tetratricopeptide repeat (TPR) domain. Mutations in AIPL1, including many missense mutations in both FKBP and TPR domains, have been associated with Leber congenital amaurosis, a severe inherited retinopathy that causes blindness. TPR-domain containing proteins are known to interact with HSP90. However, the structure of AIPL1-TPR domain is presently not determined and little is known about the contribution of the TPR domain to the chaperone function of AIPL1. Here, we report the backbone and sidechain assignments of the TPR domain of AIPL1. These assignments reveal that AIPL1-TPR is an α-helical protein containing seven α-helices connected via short loops. Peak broadening or structural disorder is observed for a cluster of hydrophobic residues of W218, W222 and L223. Therefore, these assignments provide a framework for further structural determination of AIPL1-TPR domain and its interactions with various binding partners for elucidation of the mechanism of TPR contribution to the chaperone function of AIPL1.
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Affiliation(s)
- Liping Yu
- Department of Biochemistry, University of Iowa Carver College of Medicine, B291 CBRB, 285 Newton Road, Iowa City, IA, 52242, USA.
- CCOM NMR Core Facility, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA.
| | - Ravi P Yadav
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, 5-532 BSB, 51 Newton Road, Iowa City, IA, 52242, USA
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, 5-532 BSB, 51 Newton Road, Iowa City, IA, 52242, USA.
- Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA.
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Emerling CA. Regressed but Not Gone: Patterns of Vision Gene Loss and Retention in Subterranean Mammals. Integr Comp Biol 2019; 58:441-451. [PMID: 29697812 DOI: 10.1093/icb/icy004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Regressive evolution involves the degradation of formerly useful traits as organisms invade novel ecological niches. In animals, committing to a strict subterranean habit can lead to regression of the eyes, likely due to a limited exposure to light. Several lineages of subterranean mammals show evidence of such degeneration, which can include decreased organization of the retina, malformation of the lens, and subcutaneous positioning of the eye. Advances in DNA sequencing have revealed that this regression co-occurs with a degradation of genomic loci encoding visual functions, including protein-coding genes. Other dim light-adapted vertebrates with normal ocular anatomy, such as nocturnal and aquatic species, also demonstrate evidence of visual gene loss, but the absence of comparative studies has led to the untested assumption that subterranean mammals are special in the degree of this genomic regression. Additionally, previous studies have shown that not all vision genes have been lost in subterranean mammals, but it is unclear whether they are under relaxed selection and will ultimately be lost, are maintained due to pleiotropy or if natural selection is favoring the retention of the eye and certain critical underlying loci. Here I report that vision gene loss in subterranean mammals tends to be more extensive in quantity and differs in distribution from other dim light-adapted mammals, although some committed subterranean mammals demonstrate significant overlap with nocturnal microphthalmic species. In addition, blind subterranean mammals retain functional orthologs of non-pleiotropic visual genes that are evolving at rates consistent with purifying selection. Together, these results suggest that although living underground tends to lead to major losses of visual functions, natural selection is maintaining genes that support the eye, perhaps as an organ for circadian and/or circannual entrainment.
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Affiliation(s)
- Christopher A Emerling
- Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA 94720, USA
- Institut des Sciences de l'Evolution de Montpellier (ISEM), Université de Montpellier, CNRS, IRD, EPHE, 34090 Montpellier, France
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50
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Dilan TL, Moye AR, Salido EM, Saravanan T, Kolandaivelu S, Goldberg AFX, Ramamurthy V. ARL13B, a Joubert Syndrome-Associated Protein, Is Critical for Retinogenesis and Elaboration of Mouse Photoreceptor Outer Segments. J Neurosci 2019; 39:1347-1364. [PMID: 30573647 PMCID: PMC6381253 DOI: 10.1523/jneurosci.1761-18.2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/16/2018] [Accepted: 12/12/2018] [Indexed: 11/21/2022] Open
Abstract
Mutations in the Joubert syndrome-associated small GTPase ARL13B are linked to photoreceptor impairment and vision loss. To determine the role of ARL13B in the development, function, and maintenance of ciliated photoreceptors, we generated a pan-retina knock-out (Six3-Cre) and a rod photoreceptor-specific inducible conditional knock-out (Pde6g-CreERT2) of ARL13B using murine models. Embryonic deletion of ARL13B led to defects in retinal development with reduced cell proliferation. In the absence of ARL13B, photoreceptors failed to develop outer segment (OS) membranous discs and axonemes, resulting in loss of function and rapid degeneration. Additionally, the majority of photoreceptor basal bodies did not dock properly at the apical edge of the inner segments. The removal of ARL13B in adult rod photoreceptor cells after maturation of OS resulted in loss of photoresponse and vesiculation in the OS. Before changes in photoresponse, removal of ARL13B led to mislocalization of rhodopsin, prenylated phosphodiesterase-6 (PDE6), and intraflagellar transport protein-88 (IFT88). Our findings show that ARL13B is required at multiple stages of retinogenesis, including early postnatal proliferation of retinal progenitor cells, development of photoreceptor cilia, and morphogenesis of photoreceptor OS discs regardless of sex. Last, our results establish a need for ARL13B in photoreceptor maintenance and protein trafficking.SIGNIFICANCE STATEMENT The normal development of photoreceptor cilia is essential to create functional, organized outer segments with stacked membrane discs that house the phototransduction proteins necessary for sight. Our study identifies a complex role for ARL13B, a small GTPase linked to Joubert syndrome and visual impairment, at various stages of photoreceptor development. Loss of ARL13B led to defects in retinal proliferation, altered placement of basal bodies crucial for components of the cilium (transition zone) to emanate, and absence of photoreceptor-stacked discs. These defects led to extinguished visual response and dysregulated protein trafficking. Our findings show the complex role ARL13B plays in photoreceptor development, viability, and function. Our study accounts for the severe retinal impairment observed in ARL13B-linked Joubert syndrome patients.
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Affiliation(s)
- Tanya L Dilan
- Department of Ophthalmology and Neuroscience
- Department of Biochemistry
| | - Abigail R Moye
- Department of Ophthalmology and Neuroscience
- Department of Biochemistry
| | | | | | | | | | - Visvanathan Ramamurthy
- Department of Ophthalmology and Neuroscience,
- Department of Biochemistry
- WVU Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia 26506, and
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