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Gene Therapy with Voretigene Neparvovec Improves Vision and Partially Restores Electrophysiological Function in Pre-School Children with Leber Congenital Amaurosis. Biomedicines 2022; 11:biomedicines11010103. [PMID: 36672611 PMCID: PMC9855623 DOI: 10.3390/biomedicines11010103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/20/2022] [Accepted: 12/24/2022] [Indexed: 01/03/2023] Open
Abstract
Leber congenital amaurosis caused by mutations in the RPE65 gene belongs to the most severe early-onset hereditary childhood retinopathies naturally progressing to legal blindness. The novel gene therapy voretigene neparvovec is the first approved causative treatment option for this devastating eye disease and is specifically designed to treat RPE65-mediated retinal dystrophies. Herein, we present a follow-up of the youngest treated patients in Germany so far, including four pre-school children who received treatment with voretigene neparvovec at a single treatment center between January 2020 and May 2022. All patients underwent pars plana vitrectomy with circumferential peeling of the internal limiting membrane at the injection site and subretinal injection of voretigene neparvovec. Pre- and postoperative diagnostics included imaging (spectral domain optical coherence tomography, fundus autofluorescence, fundus wide-angle imaging), electrophysiologic examination (ERG), retinal light sensitivity measurements (FST) and visual acuity testing. Behavioral changes were assessed using a questionnaire and by observing the children's vision-guided behavior in different levels of illumination. All children showed marked increase in vision-guided behavior shortly after therapy, as well as marked increase in visual acuity in the postoperative course up to full visual acuity in one child. Two eyes showed partial electrophysiological recovery of an ERG that was undetectable before treatment-a finding that has not been described in humans before.
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2
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Gao FJ, Wang DD, Li JK, Hu FY, Xu P, Chen F, Qi YH, Liu W, Li W, Zhang SH, Chang Q, Xu GZ, Wu JH. Frequency and phenotypic characteristics of RPE65 mutations in the Chinese population. Orphanet J Rare Dis 2021; 16:174. [PMID: 33952291 PMCID: PMC8097799 DOI: 10.1186/s13023-021-01807-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/31/2021] [Indexed: 11/24/2022] Open
Abstract
Background The retinoid isomerohydrolase RPE65 has received considerable attention worldwide since a successful clinical gene therapy was approved in 2017 as the first treatment for vision loss associated with RPE65-mediated inherited retinal disease. Identifying patients with RPE65 mutations is a prerequisite to assessing the patients’ eligibility to receive RPE65-targeted gene therapies, and it is necessary to identify individuals who are most likely to benefit from gene therapies. This study aimed to investigate the RPE65 mutations frequency in the Chinese population and to determine the genetic and clinical characteristics of these patients. Results Only 20 patients with RPE65 mutations were identified, and RPE65 mutations were determined to be the 14th most common among all patients with genetic diagnoses. Ten novel variants and two hotspots associated with FAP were identified. A literature review revealed that a total of 57 patients of Chinese origin were identified with pathogenic mutations in the RPE65 gene. The mean best Snellen corrected visual acuity was worse (mean 1.3 ± 1.3 LogMAR) in patients older than 20 years old than in those younger than 15 years old (0.68 ± 0.92 LogMAR). Bone spicule-like pigment deposits (BSLPs) were observed in six patients; they were older than those without BSLP and those with white-yellow dots. Genotype–phenotype analysis revealed that truncating variants seem to lead to a more severe clinical presentation, while best corrected visual acuity testing and fundus changes did not correlate with specific RPE65 variants or mutation types. Conclusions This study provides a detailed clinical-genetic assessment of patients with RPE65 mutations of Chinese origin. These results may help to elucidate RPE65 mutations in the Chinese population and may facilitate genetic counseling and the implementation of gene therapy in China. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-01807-3.
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Affiliation(s)
- Feng-Juan Gao
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China
| | - Dan-Dan Wang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China
| | - Jian-Kang Li
- BGI-Shenzhen, Shenzhen, Guangdong, China.,Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Fang-Yuan Hu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China
| | - Ping Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China
| | - Fang Chen
- BGI-Shenzhen, Shenzhen, Guangdong, China.,Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Shenzhen Engineering Laboratory for Birth Defects Screening, BGI-Shenzhen, Shenzhen, China
| | - Yu-He Qi
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China
| | - Wei Liu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China
| | - Wei Li
- BGI-Shenzhen, Shenzhen, Guangdong, China.,BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, China
| | - Sheng-Hai Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China
| | - Qing Chang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China
| | - Ge-Zhi Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China.
| | - Ji-Hong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, 200032, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Yangpu District, China.
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3
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Inverse correlation between fatty acid transport protein 4 and vision in Leber congenital amaurosis associated with RPE65 mutation. Proc Natl Acad Sci U S A 2020; 117:32114-32123. [PMID: 33257550 DOI: 10.1073/pnas.2012623117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Fatty acid transport protein 4 (FATP4), a transmembrane protein in the endoplasmic reticulum (ER), is a recently identified negative regulator of the ER-associated retinal pigment epithelium (RPE)65 isomerase necessary for recycling 11-cis-retinal, the light-sensitive chromophore of both rod and cone opsin visual pigments. The role of FATP4 in the disease progression of retinal dystrophies associated with RPE65 mutations is completely unknown. Here we show that FATP4-deficiency in the RPE results in 2.8-fold and 1.7-fold increase of 11-cis- and 9-cis-retinals, respectively, improving dark-adaptation rates as well as survival and function of rods in the Rpe65 R91W knockin (KI) mouse model of Leber congenital amaurosis (LCA). Degradation of S-opsin in the proteasomes, but not in the lysosomes, was remarkably reduced in the KI mouse retinas lacking FATP4. FATP4-deficiency also significantly rescued S-opsin trafficking and M-opsin solubility in the KI retinas. The number of S-cones in the inferior retinas of 4- or 6-mo-old KI;Fatp4 -/- mice was 7.6- or 13.5-fold greater than those in age-matched KI mice. Degeneration rates of S- and M-cones are negatively correlated with expression levels of FATP4 in the RPE of the KI, KI;Fatp4 +/- , and KI;Fatp4 -/- mice. Moreover, the visual function of S- and M-cones is markedly preserved in the KI;Fatp4 -/- mice, displaying an inverse correlation with the FATP4 expression levels in the RPE of the three mutant lines. These findings establish FATP4 as a promising therapeutic target to improve the visual cycle, as well as survival and function of cones and rods in patients with RPE65 mutations.
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Li S, Green JF, Jin M. Impacts of deletion and ichthyosis prematurity syndrome-associated mutations in fatty acid transport protein 4 on the function of RPE65. FEBS Lett 2019; 594:540-552. [PMID: 31595490 DOI: 10.1002/1873-3468.13633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/16/2019] [Accepted: 09/16/2019] [Indexed: 12/23/2022]
Abstract
The retinal pigment epithelium-specific 65 kDa (RPE65) isomerase plays a pivotal role in photoreceptor survival and function. RPE65-catalyzed synthesis of 11-cis-retinol from all-trans-retinyl esters in the visual cycle is negatively regulated, through a heretofore unknown mechanism, by the fatty acid transport protein FATP4, mutations in which are associated with ichthyosis prematurity syndrome (IPS). Here, we analyzed the interaction between deletion mutants of FATP4 and RPE65 and the impacts of IPS-associated FATP4 mutations on RPE65 expression, 11-cis-retinol synthesis, and all-trans-retinyl ester synthesis. Our results suggest that the interaction between FATP4 and RPE65 contributes to the inhibition of RPE65 function and that IPS-associated nonsense and missense mutations in FATP4 have different effects on the visual cycle.
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Affiliation(s)
- Songhua Li
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, New Orleans, LA, USA
| | - John F Green
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, New Orleans, LA, USA
| | - Minghao Jin
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, New Orleans, LA, USA.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, LA, USA
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5
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Chen TM, Lai MC, Li YH, Chan YL, Wu CH, Wang YM, Chien CW, Huang SY, Sun HS, Tsai SJ. hnRNPM induces translation switch under hypoxia to promote colon cancer development. EBioMedicine 2019; 41:299-309. [PMID: 30852162 PMCID: PMC6444133 DOI: 10.1016/j.ebiom.2019.02.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 02/28/2019] [Accepted: 02/28/2019] [Indexed: 12/31/2022] Open
Abstract
Background Hypoxia suppresses global protein production, yet certain essential proteins are translated through alternative pathways to survive under hypoxic stress. Translation via the internal ribosome entry site (IRES) is a means to produce proteins under stress conditions such as hypoxia; however, the underlying mechanism remains largely uncharacterized. Methods Proteomic and bioinformatic analyses were employed to identify hnRNPM as an IRES interacting factor. Clinical specimens and mouse model of tumorigenesis were used for determining the expression and correlation of hnRNPM and its target gene. Transcriptomic and translatomic analyses were performed to profile target genes regulated by hnRNPM. Findings Hypoxia increases cytosolic hnRNPM binding onto its target mRNAs and promotes translation initiation. Clinical colon cancer specimens and mouse carcinogenesis model showed that hnRNPM is elevated during the development of colorectal cancer, and is associated with poor prognosis. Genome-wide transcriptomics and translatomics analyses revealed a unique set of hnRNPM-targeted genes involved in metabolic processes and cancer neoplasia are selectively translated under hypoxia. Interpretation These data highlight the critical role of hnRNPM-IRES-mediated translation in transforming hypoxia-induced proteome toward malignancy. Fund This work was supported by the Ministry of Science and Technology, Taiwan (MOST 104–2320-B-006-042 to HSS and MOST 105–2628-B-001-MY3 to TMC).
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Affiliation(s)
- Tsung-Ming Chen
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department and Graduate Institute of Aquaculture, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Ming-Chih Lai
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Han Li
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ya-Ling Chan
- Institute of Bioinformatics and Biosignaling, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Chih-Hao Wu
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ming Wang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chun-Wei Chien
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - San-Yuan Huang
- Department of Animal Science, National Chung Hsing University, Taichung, Taiwan
| | - H Sunny Sun
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
| | - Shaw-Jenq Tsai
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Choi EH, Suh S, Sander CL, Hernandez CJO, Bulman ER, Khadka N, Dong Z, Shi W, Palczewski K, Kiser PD. Insights into the pathogenesis of dominant retinitis pigmentosa associated with a D477G mutation in RPE65. Hum Mol Genet 2019; 27:2225-2243. [PMID: 29659842 DOI: 10.1093/hmg/ddy128] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/06/2018] [Indexed: 12/31/2022] Open
Abstract
RPE65 is the essential trans-cis isomerase of the classical retinoid (visual) cycle. Mutations in RPE65 give rise to severe retinal dystrophies, most of which are associated with loss of protein function and recessive inheritance. The only known exception is a c.1430G>A (D477G) mutation that gives rise to dominant retinitis pigmentosa with delayed onset and choroidal and macular involvement. Position 477 is distant from functionally critical regions of RPE65. Hence, the mechanism of D477G pathogenicity remains unclear, although protein misfolding and aggregation mechanisms have been suggested. We characterized a D477G knock-in mouse model which exhibited mild age-dependent changes in retinal structure and function. Immunoblot analysis of protein extracts from the eyes of these knock-in mice demonstrated the presence of ubiquitinated RPE65 and reduced RPE65 expression. We observed an accumulation of retinyl esters in the knock-in mice as well as a delay in rhodopsin regeneration kinetics and diminished electroretinography responses, indicative of RPE65 functional impairment induced by the D477G mutation in vivo. However, a cell line expressing D477G RPE65 revealed protein expression levels, cellular localization and retinoid isomerase activity comparable to cells expressing wild-type protein. Structural analysis of an RPE65 chimera suggested that the D477G mutation does not perturb protein folding or tertiary structure. Instead, the mutation generates an aggregation-prone surface that could induce cellular toxicity through abnormal complex formation as suggested by crystal packing analysis. These results indicate that a toxic gain-of-function induced by the D477G RPE65 substitution may play a role in the pathogenesis of this form of dominant retinitis pigmentosa.
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Affiliation(s)
- Elliot H Choi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Susie Suh
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Christopher L Sander
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Christian J Ortiz Hernandez
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,University of Puerto Rico at Humacao, Humacao, PR, USA
| | - Elizabeth R Bulman
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA
| | - Nimesh Khadka
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zhiqian Dong
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Polgenix Inc., Cleveland, OH 44106, USA
| | - Wuxian Shi
- National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Philip D Kiser
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH 44106, USA
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7
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Pharmacological Amelioration of Cone Survival and Vision in a Mouse Model for Leber Congenital Amaurosis. J Neurosci 2017; 36:5808-19. [PMID: 27225770 DOI: 10.1523/jneurosci.3857-15.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 04/20/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED RPE65, an abundant membrane-associate protein in the retinal pigment epithelium (RPE), is a key retinoid isomerase of the visual cycle necessary for generating 11-cis-retinal that functions not only as a molecular switch for activating cone and rod visual pigments in response to light stimulation, but also as a chaperone for normal trafficking of cone opsins to the outer segments. Many mutations in RPE65 are associated with Leber congenital amaurosis (LCA). A R91W substitution, the most frequent LCA-associated mutation, results in a severe decrease in protein level and enzymatic activity of RPE65, causing cone opsin mislocalization and early cone degeneration in the mutation knock-in mouse model of LCA. Here we show that R91W RPE65 undergoes ubiquitination-dependent proteasomal degradation in the knock-in mouse RPE due to misfolding. The 26S proteasome non-ATPase regulatory subunit 13 mediated degradation specifically of misfolded R91W RPE65. The mutation disrupted membrane-association and colocalization of RPE65 with lecithin:retinol acyltransferase (LRAT) that provides the hydrophobic substrate for RPE65. Systemic administration of sodium 4-phenylbutyrate (PBA), a chemical chaperone, increased protein stability, enzymatic activity, membrane-association, and colocalization of R91W RPE65 with LRAT. This rescue effect increased synthesis of 11-cis-retinal and 9-cis-retinal, a functional iso-chromophore of the visual pigments, led to alleviation of S-opsin mislocalization and cone degeneration in the knock-in mice. Importantly, PBA-treatment also improved cone-mediated vision in the mutant mice. These results indicate that PBA, a U.S. Food and Drug Administration-approved safe oral medication, may provide a noninvasive therapeutic intervention that delays daylight vision loss in patients with RPE65 mutations. SIGNIFICANCE STATEMENT LCA is a severe early onset retinal dystrophy. Recent clinical trials of gene therapy have implicated the need of an alternative or combination therapy to improve cone survival and function in patients with LCA caused by RPE65 mutations. Using a mouse model carrying the most frequent LCA-associated mutation (R91W), we found that the mutant RPE65 underwent ubiquitination-dependent proteasomal degradation due to misfolding. Treatment of the mice with a chemical chaperone partially corrected stability, enzymatic activity, and subcellular localization of R91W RPE65, which was also accompanied by improvement of cone survival and vision. These findings identify an in vivo molecular pathogenic mechanism for R91W mutation and provide a feasible pharmacological approach that can delay vision loss in patients with RPE65 mutations.
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Biswas P, Chavali VRM, Agnello G, Stone E, Chakarova C, Duncan JL, Kannabiran C, Homsher M, Bhattacharya SS, Naeem MA, Kimchi A, Sharon D, Iwata T, Riazuddin S, Reddy GB, Hejtmancik JF, Georgiou G, Riazuddin SA, Ayyagari R. A missense mutation in ASRGL1 is involved in causing autosomal recessive retinal degeneration. Hum Mol Genet 2016; 25:2483-2497. [PMID: 27106100 DOI: 10.1093/hmg/ddw113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/22/2016] [Accepted: 04/11/2016] [Indexed: 12/31/2022] Open
Abstract
Inherited retinal dystrophies are a group of genetically heterogeneous conditions with broad phenotypic heterogeneity. We analyzed a large five-generation pedigree with early-onset recessive retinal degeneration to identify the causative mutation. Linkage analysis and homozygosity mapping combined with exome sequencing were carried out to map the disease locus and identify the p.G178R mutation in the asparaginase like-1 gene (ASRGL1), segregating with the retinal dystrophy phenotype in the study pedigree. ASRGL1 encodes an enzyme that catalyzes the hydrolysis of L-asparagine and isoaspartyl-peptides. Studies on the ASRGL1 expressed in Escherichia coli and transiently transfected mammalian cells indicated that the p.G178R mutation impairs the autocatalytic processing of this enzyme resulting in the loss of functional ASRGL1 and leaving the inactive precursor protein as a destabilized and aggregation-prone protein. A zebrafish model overexpressing the mutant hASRGL1 developed retinal abnormalities and loss of cone photoreceptors. Our studies suggest that the p.G178R mutation in ASRGL1 leads to photoreceptor degeneration resulting in progressive vision loss.
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Affiliation(s)
- Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
| | - Venkata Ramana Murthy Chavali
- Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA.,Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Giulia Agnello
- Departments of Biomedical and Chemical Engineering, Molecular Biosciences, Section of Molecular Genetics and Microbiology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - Everett Stone
- Departments of Biomedical and Chemical Engineering, Molecular Biosciences, Section of Molecular Genetics and Microbiology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | | | - Jacque L Duncan
- Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, L V Prasad Eye Institute (LVPEI), Kallam Anji Reddy Campus, L V Prasad Marg, Hyderabad 500 034, India
| | - Melissa Homsher
- Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Adva Kimchi
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Shaikh Riazuddin
- Allama Iqbal Medical College, University of Health Sciences Lahore, Pakistan.,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | | | | | - George Georgiou
- Departments of Biomedical and Chemical Engineering, Molecular Biosciences, Section of Molecular Genetics and Microbiology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - S Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
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Comparative sequence analyses of rhodopsin and RPE65 reveal patterns of selective constraint across hereditary retinal disease mutations. Vis Neurosci 2016; 33:e002. [DOI: 10.1017/s0952523815000322] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractRetinitis pigmentosa (RP) comprises several heritable diseases that involve photoreceptor, and ultimately retinal, degeneration. Currently, mutations in over 50 genes have known links to RP. Despite advances in clinical characterization, molecular characterization of RP remains challenging due to the heterogeneous nature of causal genes, mutations, and clinical phenotypes. In this study, we compiled large datasets of two important visual genes associated with RP: rhodopsin, which initiates the phototransduction cascade, and the retinoid isomerase RPE65, which regenerates the visual cycle. We used a comparative evolutionary approach to investigate the relationship between interspecific sequence variation and pathogenic mutations that lead to degenerative retinal disease. Using codon-based likelihood methods, we estimated evolutionary rates (dN/dS) across both genes in a phylogenetic context to investigate differences between pathogenic and nonpathogenic amino acid sites. In both genes, disease-associated sites showed significantly lower evolutionary rates compared to nondisease sites, and were more likely to occur in functionally critical areas of the proteins. The nature of the dataset (e.g., vertebrate or mammalian sequences), as well as selection of pathogenic sites, affected the differences observed between pathogenic and nonpathogenic sites. Our results illustrate that these methods can serve as an intermediate step in understanding protein structure and function in a clinical context, particularly in predicting the relative pathogenicity (i.e., functional impact) of point mutations and their downstream phenotypic effects. Extensions of this approach may also contribute to current methods for predicting the deleterious effects of candidate mutations and to the identification of protein regions under strong constraint where we expect pathogenic mutations to occur.
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