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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] [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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Aweidah H, Xi Z, Sahel JA, Byrne LC. PRPF31-retinitis pigmentosa: Challenges and opportunities for clinical translation. Vision Res 2023; 213:108315. [PMID: 37714045 PMCID: PMC10872823 DOI: 10.1016/j.visres.2023.108315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/17/2023]
Abstract
Mutations in pre-mRNA processing factor 31 cause autosomal dominant retinitis pigmentosa (PRPF31-RP), for which there is currently no efficient treatment, making this disease a prime target for the development of novel therapeutic strategies. PRPF31-RP exhibits incomplete penetrance due to haploinsufficiency, in which reduced levels of gene expression from the mutated allele result in disease. A variety of model systems have been used in the investigation of disease etiology and therapy development. In this review, we discuss recent advances in both in vivo and in vitro model systems, evaluating their advantages and limitations in the context of therapy development for PRPF31-RP. Additionally, we describe the latest approaches for treatment, including AAV-mediated gene augmentation, genome editing, and late-stage therapies such as optogenetics, cell transplantation, and retinal prostheses.
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Affiliation(s)
- Hamzah Aweidah
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zhouhuan Xi
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Ophthalmology, Eye Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - José-Alain Sahel
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Leah C Byrne
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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3
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Krausová M, Kreplová M, Banik P, Cvačková Z, Kubovčiak J, Modrák M, Zudová D, Lindovský J, Kubik-Zahorodna A, Pálková M, Kolář M, Procházka J, Sedláček R, Staněk D. Retinitis pigmentosa-associated mutations in mouse Prpf8 cause misexpression of circRNAs and degeneration of cerebellar granule cells. Life Sci Alliance 2023; 6:e202201855. [PMID: 37019475 PMCID: PMC10078954 DOI: 10.26508/lsa.202201855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 04/07/2023] Open
Abstract
A subset of patients with retinitis pigmentosa (RP) carry mutations in several spliceosomal components including the PRPF8 protein. Here, we established two alleles of murine Prpf8 that genocopy or mimic aberrant PRPF8 found in RP patients-the substitution p.Tyr2334Asn and an extended protein variant p.Glu2331ValfsX15. Homozygous mice expressing the aberrant Prpf8 variants developed within the first 2 mo progressive atrophy of the cerebellum because of extensive granule cell loss, whereas other cerebellar cells remained unaffected. We further show that a subset of circRNAs were deregulated in the cerebellum of both Prpf8-RP mouse strains. To identify potential risk factors that sensitize the cerebellum for Prpf8 mutations, we monitored the expression of several splicing proteins during the first 8 wk. We observed down-regulation of all selected splicing proteins in the WT cerebellum, which coincided with neurodegeneration onset. The decrease in splicing protein expression was further pronounced in mouse strains expressing mutated Prpf8. Collectively, we propose a model where physiological reduction in spliceosomal components during postnatal tissue maturation sensitizes cells to the expression of aberrant Prpf8 and the subsequent deregulation of circRNAs triggers neuronal death.
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Affiliation(s)
- Michaela Krausová
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Michaela Kreplová
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Poulami Banik
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Zuzana Cvačková
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Kubovčiak
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Modrák
- Core Facility Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Dagmar Zudová
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Jiří Lindovský
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Agnieszka Kubik-Zahorodna
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Marcela Pálková
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Michal Kolář
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Procházka
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Radislav Sedláček
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - David Staněk
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
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Cellular and Molecular Mechanisms of Pathogenesis Underlying Inherited Retinal Dystrophies. Biomolecules 2023; 13:biom13020271. [PMID: 36830640 PMCID: PMC9953031 DOI: 10.3390/biom13020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation.
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Gene augmentation prevents retinal degeneration in a CRISPR/Cas9-based mouse model of PRPF31 retinitis pigmentosa. Nat Commun 2022; 13:7695. [PMID: 36509783 PMCID: PMC9744804 DOI: 10.1038/s41467-022-35361-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 11/29/2022] [Indexed: 12/14/2022] Open
Abstract
Mutations in PRPF31 cause autosomal dominant retinitis pigmentosa, an untreatable form of blindness. Gene therapy is a promising treatment for PRPF31-retinitis pigmentosa, however, there are currently no suitable animal models in which to develop AAV-mediated gene augmentation. Here we establish Prpf31 mutant mouse models using AAV-mediated CRISPR/Cas9 knockout, and characterize the resulting retinal degeneration phenotype. Mouse models with early-onset morphological and functional impairments like those in patients were established, providing new platforms in which to investigate pathogenetic mechanisms and develop therapeutic methods. AAV-mediated PRPF31 gene augmentation restored the retinal structure and function in a rapidly degenerating mouse model, demonstrating the first in vivo proof-of-concept for AAV-mediated gene therapy to treat PRPF31-retinitis pigmentosa. AAV-CRISPR/Cas9-PRPF31 knockout constructs also mediated efficient PRPF31 knockout in human and non-human primate retinal explants, laying a foundation for establishing non-human primate models using the method developed here.
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Xiao X, Ling F, Chen CB, Liang J, Cao Y, Xu Y, Chen H. PRPF31 interacts with PRPH2 confirmed by co-immunoprecipitation and co-localization. Biochem Biophys Res Commun 2022; 629:12-16. [PMID: 36088804 DOI: 10.1016/j.bbrc.2022.08.090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/22/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022]
Abstract
Both PRPF31 and PRPH2 are the causative genes for retinitis pigmentosa. And both of them are associated with the balance of rhodopsin. In this study, we aim to investigate the co-expression and interaction of PRPF31 and PRPH2. We used PRPF31-eGFP, PRPF31-3xFlag and PRPH2-mCherry vectors were transfected into HEK293T and APRE-19 cells. Immunoblotting and co-immunoprecipitation (Co-IP) were used for gene expression validation and protein interaction. Immunofluorescence staining assay was used to test the co-localization analysis of PRPF31 and PRPH2. Co-IP experiments showed that PRPF31 could be pulled down with an anti-PRPH2 antibody. There was co-localization between PRPF31 and PRPH2 in HEK293T, APRE-19 and mouse retina. The Co-IP and co-localization experiments suggest that PRPF31 interacted with PRPH2.
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Affiliation(s)
- Xiaoqiang Xiao
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Fangyi Ling
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Chong-Bo Chen
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Jiajian Liang
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Yingjie Cao
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Yanxuan Xu
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Haoyu Chen
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China.
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Nazlamova L, Villa Vasquez SS, Lord J, Karthik V, Cheung MK, Lakowski J, Wheway G. Microtubule modification defects underlie cilium degeneration in cell models of retinitis pigmentosa associated with pre-mRNA splicing factor mutations. Front Genet 2022; 13:1009430. [PMID: 36176300 PMCID: PMC9513239 DOI: 10.3389/fgene.2022.1009430] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 08/19/2022] [Indexed: 11/17/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most common cause of hereditary blindness, and may occur in isolation as a non-syndromic condition or alongside other features in a syndromic presentation. Biallelic or monoallelic mutations in one of eight genes encoding pre-mRNA splicing factors are associated with non-syndromic RP. The molecular mechanism of disease remains incompletely understood, limiting opportunities for targeted treatment. Here we use CRISPR and base edited PRPF6 and PRPF31 mutant cell lines, and publicly-available data from human PRPF31+/− patient derived retinal organoids and PRPF31 siRNA-treated organotypic retinal cultures to confirm an enrichment of differential splicing of microtubule, centrosomal, cilium and DNA damage response pathway genes in these cells. We show that genes with microtubule/centrosome/centriole/cilium gene ontology terms are enriched for weak 3′ and 5′ splice sites, and that subtle defects in spliceosome activity predominantly affect efficiency of splicing of these exons. We suggest that the primary defect in PRPF6 or PRPF31 mutant cells is microtubule and centrosomal defects, leading to defects in cilium and mitotic spindle stability, with the latter leading to DNA damage, triggering differential splicing of DNA damage response genes to activate this pathway. Finally, we expand understanding of “splicing factor RP” by investigating the function of TTLL3, one of the most statistically differentially expressed genes in PRPF6 and PRPF31 mutant cells. We identify that TTLL3 is the only tubulin glycylase expressed in the human retina, essential for monoglycylation of microtubules of the cilium, including the retinal photoreceptor cilium, to prevent cilium degeneration and retinal degeneration. Our preliminary data suggest that rescue of tubulin glycylation through overexpression of TTLL3 is sufficient to rescue cilium number in PRPF6 and PRPF31 mutant cells, suggesting that this defect underlies the cellular defect and may represent a potential target for therapeutic intervention in this group of disorders.
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Affiliation(s)
- Liliya Nazlamova
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Suly Saray Villa Vasquez
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Jenny Lord
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Varshini Karthik
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Man-Kim Cheung
- Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - Jörn Lakowski
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Gabrielle Wheway
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- *Correspondence: Gabrielle Wheway,
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8
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Liu W, Liu S, Li P, Yao K. Retinitis Pigmentosa: Progress in Molecular Pathology and Biotherapeutical Strategies. Int J Mol Sci 2022; 23:ijms23094883. [PMID: 35563274 PMCID: PMC9101511 DOI: 10.3390/ijms23094883] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa (RP) is genetically heterogeneous retinopathy caused by photoreceptor cell death and retinal pigment epithelial atrophy that eventually results in blindness in bilateral eyes. Various photoreceptor cell death types and pathological phenotypic changes that have been disclosed in RP demand in-depth research of its pathogenic mechanism that may account for inter-patient heterogeneous responses to mainstream drug treatment. As the primary method for studying the genetic characteristics of RP, molecular biology has been widely used in disease diagnosis and clinical trials. Current technology iterations, such as gene therapy, stem cell therapy, and optogenetics, are advancing towards precise diagnosis and clinical applications. Specifically, technologies, such as effective delivery vectors, CRISPR/Cas9 technology, and iPSC-based cell transplantation, hasten the pace of personalized precision medicine in RP. The combination of conventional therapy and state-of-the-art medication is promising in revolutionizing RP treatment strategies. This article provides an overview of the latest research on the pathogenesis, diagnosis, and treatment of retinitis pigmentosa, aiming for a convenient reference of what has been achieved so far.
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9
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Obuća M, Cvačková Z, Kubovčiak J, Kolář M, Staněk D. Retinitis pigmentosa-linked mutation in DHX38 modulates its splicing activity. PLoS One 2022; 17:e0265742. [PMID: 35385551 PMCID: PMC8985939 DOI: 10.1371/journal.pone.0265742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 03/07/2022] [Indexed: 01/21/2023] Open
Abstract
Retinitis pigmentosa (RP) is a hereditary disease affecting tens of thousands of people world-wide. Here we analyzed the effect of an amino acid substitution in the RNA helicase DHX38 (Prp16) causing RP. DHX38 has been proposed as the helicase important for the 2nd step of splicing. We showed that DHX38 associates with key splicing factors involved in both splicing steps but did not find any evidence that the RP mutations changes DHX38 interaction profile with the spliceosome. We further downregulated DHX38 and monitored changes in splicing. We observed only minor perturbations of general splicing but detected modulation of ~70 alternative splicing events. Next, we probed DHX38 function in splicing of retina specific genes and found that FSCN2 splicing is dependent on DHX38. In addition, RHO splicing was inhibited specifically by expression of DHX38 RP variant. Finally, we showed that overexpression of DHX38 promotes usage of canonical as well as cryptic 5' splice sites in HBB splicing reporter. Together, our data show that DHX38 is a splicing factor that promotes splicing of cryptic splice sites and regulate alternative splicing. We further provide evidence that the RP-linked substitution G332D modulates DHX38 splicing activity.
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Affiliation(s)
- Mina Obuća
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Zuzana Cvačková
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Kubovčiak
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Michal Kolář
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Staněk
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail:
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Yang C, Georgiou M, Atkinson R, Collin J, Al-Aama J, Nagaraja-Grellscheid S, Johnson C, Ali R, Armstrong L, Mozaffari-Jovin S, Lako M. Pre-mRNA Processing Factors and Retinitis Pigmentosa: RNA Splicing and Beyond. Front Cell Dev Biol 2021; 9:700276. [PMID: 34395430 PMCID: PMC8355544 DOI: 10.3389/fcell.2021.700276] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 07/09/2021] [Indexed: 12/20/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most common inherited retinal disease characterized by progressive degeneration of photoreceptors and/or retinal pigment epithelium that eventually results in blindness. Mutations in pre-mRNA processing factors (PRPF3, 4, 6, 8, 31, SNRNP200, and RP9) have been linked to 15–20% of autosomal dominant RP (adRP) cases. Current evidence indicates that PRPF mutations cause retinal specific global spliceosome dysregulation, leading to mis-splicing of numerous genes that are involved in a variety of retina-specific functions and/or general biological processes, including phototransduction, retinol metabolism, photoreceptor disk morphogenesis, retinal cell polarity, ciliogenesis, cytoskeleton and tight junction organization, waste disposal, inflammation, and apoptosis. Importantly, additional PRPF functions beyond RNA splicing have been documented recently, suggesting a more complex mechanism underlying PRPF-RPs driven disease pathogenesis. The current review focuses on the key RP-PRPF genes, depicting the current understanding of their roles in RNA splicing, impact of their mutations on retinal cell’s transcriptome and phenome, discussed in the context of model species including yeast, zebrafish, and mice. Importantly, information on PRPF functions beyond RNA splicing are discussed, aiming at a holistic investigation of PRPF-RP pathogenesis. Finally, work performed in human patient-specific lab models and developing gene and cell-based replacement therapies for the treatment of PRPF-RPs are thoroughly discussed to allow the reader to get a deeper understanding of the disease mechanisms, which we believe will facilitate the establishment of novel and better therapeutic strategies for PRPF-RP patients.
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Affiliation(s)
- Chunbo Yang
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Maria Georgiou
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert Atkinson
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Joseph Collin
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jumana Al-Aama
- Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Colin Johnson
- Leeds Institute of Molecular Medicine, University of Leeds, Leeds, United Kingdom
| | - Robin Ali
- King's College London, London, United Kingdom
| | - Lyle Armstrong
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Sina Mozaffari-Jovin
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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Li J, Liu F, Lv Y, Sun K, Zhao Y, Reilly J, Zhang Y, Tu J, Yu S, Liu X, Qin Y, Huang Y, Gao P, Jia D, Chen X, Han Y, Shu X, Luo D, Tang Z, Liu M. Prpf31 is essential for the survival and differentiation of retinal progenitor cells by modulating alternative splicing. Nucleic Acids Res 2021; 49:2027-2043. [PMID: 33476374 PMCID: PMC7913766 DOI: 10.1093/nar/gkab003] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 01/01/2021] [Accepted: 01/05/2021] [Indexed: 12/23/2022] Open
Abstract
Dysfunction of splicing factors often result in abnormal cell differentiation and apoptosis, especially in neural tissues. Mutations in pre-mRNAs processing factor 31 (PRPF31) cause autosomal dominant retinitis pigmentosa, a progressive retinal degeneration disease. The transcriptome-wide splicing events specifically regulated by PRPF31 and their biological roles in the development and maintenance of retina are still unclear. Here, we showed that the differentiation and viability of retinal progenitor cells (RPCs) are severely perturbed in prpf31 knockout zebrafish when compared with other tissues at an early embryonic stage. At the cellular level, significant mitotic arrest and DNA damage were observed. These defects could be rescued by the wild-type human PRPF31 rather than the disease-associated mutants. Further bioinformatic analysis and experimental verification uncovered that Prpf31 deletion predominantly causes the skipping of exons with a weak 5′ splicing site. Moreover, genes necessary for DNA repair and mitotic progression are most enriched among the differentially spliced events, which may explain the cellular and tissular defects in prpf31 mutant retinas. This is the first time that Prpf31 is demonstrated to be essential for the survival and differentiation of RPCs during retinal neurogenesis by specifically modulating the alternative splicing of genes involved in DNA repair and mitosis.
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Affiliation(s)
- Jingzhen Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Fei Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Yuexia Lv
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Kui Sun
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Yuntong Zhao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Science, Wuhan 430072, PR China
| | - Jamas Reilly
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, Scotland, UK
| | - Yangjun Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Jiayi Tu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Shanshan Yu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Xiliang Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Yayun Qin
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Yuwen Huang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Pan Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Danna Jia
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Xiang Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Yunqiao Han
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, Scotland, UK
| | - Daji Luo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Science, Wuhan 430072, PR China
| | - Zhaohui Tang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
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Hebbar S, Lehmann M, Behrens S, Hälsig C, Leng W, Yuan M, Winkler S, Knust E. Mutations in the splicing regulator Prp31 lead to retinal degeneration in Drosophila. Biol Open 2021; 10:10/1/bio052332. [PMID: 33495354 PMCID: PMC7860132 DOI: 10.1242/bio.052332] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Retinitis pigmentosa (RP) is a clinically heterogeneous disease affecting 1.6 million people worldwide. The second-largest group of genes causing autosomal dominant RP in human encodes regulators of the splicing machinery. Yet, how defects in splicing factor genes are linked to the aetiology of the disease remains largely elusive. To explore possible mechanisms underlying retinal degeneration caused by mutations in regulators of the splicing machinery, we induced mutations in Drosophila Prp31, the orthologue of human PRPF31, mutations in which are associated with RP11. Flies heterozygous mutant for Prp31 are viable and develop normal eyes and retina. However, photoreceptors degenerate under light stress, thus resembling the human disease phenotype. Degeneration is associated with increased accumulation of the visual pigment rhodopsin 1 and increased mRNA levels of twinfilin, a gene associated with rhodopsin trafficking. Reducing rhodopsin levels by raising animals in a carotenoid-free medium not only attenuates rhodopsin accumulation, but also retinal degeneration. Given a similar importance of proper rhodopsin trafficking for photoreceptor homeostasis in human, results obtained in flies presented here will also contribute to further unravel molecular mechanisms underlying the human disease. This paper has an associated First Person interview with the co-first authors of the article. Summary: Retinitis pigmentosa (RP) is a human disease resulting in blindness, which affects 1 in 4.000 people worldwide. So far >90 genes have been identified that are causally related to RP. Mutations in the splicing factor PRPF31 are linked to RP11. We induced mutations in the Drosophila orthologue Prp31 and show that flies heterozygous for Prp31 undergo light-dependent retinal degeneration. Degeneration is associated with increased accumulation of the light-sensitive molecule, rhodopsin 1. In fact, reducing rhodopsin levels by dietary intervention modifies the extent of retinal degeneration. This model will further contribute to better understand the aetiology of the human disease.
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Affiliation(s)
- Sarita Hebbar
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Malte Lehmann
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Sarah Behrens
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Catrin Hälsig
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Weihua Leng
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Michaela Yuan
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Sylke Winkler
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Elisabeth Knust
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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Cao L, Peng C, Yu J, Jiang W, Yang J. Identification of two novel PRPF31 mutations in Chinese families with non-syndromic autosomal dominant retinitis pigmentosa. Mol Genet Genomic Med 2020; 8:e1537. [PMID: 33085829 PMCID: PMC7767543 DOI: 10.1002/mgg3.1537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/30/2020] [Accepted: 10/02/2020] [Indexed: 12/05/2022] Open
Abstract
Background Retinitis pigmentosa is a heterogeneous group of inherited retinal diseases leading to progressive vision loss. It has been estimated that the etiology is still unclear in 22%‐40% of cases, indicating that many novel pathogenic variations related to RP remain unidentified in many patients. In this study, our aim was to investigate the disease‐causing variants and function of the variants in two Chinese families with non‐syndromic autosomal dominant retinitis pigmentosa (adRP). Methods Clinical data and peripheral blood DNA samples were collected. Whole exome sequencing (WES) was conducted to screen for variations. Then, the expression of green fluorescent protein (GFP)‐fused wild‐type PRPF31 protein and its variants was evaluated via western blotting and GFP fluorescence detection in vitro. Results Two novel heterozygous variants of PRPF31 (NM_015629.4): c.855+5G>A and c.849_855del (p.Pro284Ilefs*35) were identified respectively in two families. The variant c.855+5G>A is co‐segregated with the disease in adRP‐01 family. The pedigree analysis result for c.849_855del (p. Pro284Ilefs*35) shows an inheritance pattern with incomplete penetrance for adRP‐02 family. The RT‐PCR analysis shows the PRPF31 gene c.855+5G>A leading to the missing from the 997th to the 1405th positions of the PRPF31 gene (NM_015629.4) cDNA. The expressions of the mutant GFP‐fused PRPF31 protein were not detected in HEK293 cells or Cos7 cells via western blotting and immunofluorescence. Conclusions Our findings identified two novel variants in PRPF31 in two Chinese families with adRP, expanding the mutational spectrum of this gene. Functional analysis reveals that these variants lead to the truncation of the PRPF31 protein.
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Affiliation(s)
- Li Cao
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Chunyan Peng
- The Key Laboratory for Human Disease Gene Study of Sichuan Province, Prenatal Diagnosis Center, Sichuan Provincial People's Hospital, the University of Electronic Science and Technology of China, Chengdu, PR China.,School of Medicine, University of Electronic Science and Technology of China, Chengdu, PR China
| | - Jing Yu
- College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Wei Jiang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province, Prenatal Diagnosis Center, Sichuan Provincial People's Hospital, the University of Electronic Science and Technology of China, Chengdu, PR China.,School of Medicine, University of Electronic Science and Technology of China, Chengdu, PR China
| | - Jiyun Yang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province, Prenatal Diagnosis Center, Sichuan Provincial People's Hospital, the University of Electronic Science and Technology of China, Chengdu, PR China.,School of Medicine, University of Electronic Science and Technology of China, Chengdu, PR China
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14
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Yang D, Yao Q, Li Y, Xu Y, Wang J, Zhao H, Liu F, Zhang Z, Liu Y, Bie X, Wang Y, Xu L, Luan Y, Yang S, Yang G, He Y. A c.544_618del75bp mutation in the splicing factor gene PRPF31 is involved in non-syndromic retinitis pigmentosa by reducing the level of mRNA expression. Ophthalmic Physiol Opt 2020; 40:289-299. [PMID: 32031697 DOI: 10.1111/opo.12672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 01/02/2020] [Indexed: 01/08/2023]
Abstract
PURPOSE A previous study reported a novel c.544_618del75bp mutation in exon 7 of the PRPF31 gene in a Chinese family with autosomal dominant retinal pigmentosa (ADRP). However, the selected pedigree was a small part of the whole family and the function of the c.544_618del75bp mutation was not explored deeply. The aim of the present study was to validate the previous results and explore the functional significance of the c.544_618del75bp mutation. METHODS We extended the size of the ADRP pedigree and sequenced DNA and cDNA of the PRPF31 gene for all members of the family and 100 healthy controls. Real-time quantitative polymerase chain reaction (PCR) analysis was performed on the cDNA of patients in the family and cell culture, plasmids transfection and western blot analysis were done to evaluate the functional effect of the mutation in vitro. RESULTS Sanger sequencing showed that the mutation was present in all patients and absent in all normal individuals, except for participant III-9. Bioinformatics analysis revealed that the c.544_618del75bp mutation caused a 25 amino acid deletion in the PRPF31 protein. In addition, the mRNA expression assay revealed that the mRNA expression level of the PRPF31 and RP9 genes were significantly lower in RP patients than controls (p < 0.05). Finally, the in vitro transfection assay demonstrated that the mRNA expression level of the mutant transfection group was significantly lower than the wild-type transfection group (p < 0.05). CONCLUSIONS Our study suggested that the c.544_618del75bp mutation in the PRPF31 gene was a causative mutation in this ADRP family and affected the expression of RP9 gene by influencing the formation of U4/U6-U5 tri-snRNP, eventually leading to the occurrence of RP.
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Affiliation(s)
- Dongzhi Yang
- School of Life Sciences, Zhengzhou University, Zhengzhou, China
| | - Qihui Yao
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Ya Li
- Henan Eye Institute, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yan Xu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Jun Wang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Huiling Zhao
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Fuyong Liu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhaojing Zhang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yang Liu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xiaoshuai Bie
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yuanli Wang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Liyan Xu
- Henan Eye Institute, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yingying Luan
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shangdong Yang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Ge Yang
- Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ying He
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
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Hamieh A, Nandrot EF. Retinal Pigment Epithelial Cells: The Unveiled Component in the Etiology of Prpf Splicing Factor-Associated Retinitis Pigmentosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:227-231. [PMID: 31884616 DOI: 10.1007/978-3-030-27378-1_37] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pre-mRNA splicing is a critical step in RNA processing in all eukaryotic cells. It consists of introns removal and requires the assembly of a large RNA-protein complex called the spliceosome. This complex of small nuclear ribonucleoproteins is associated with accessory proteins from the pre-mRNA processing factor (PRPF) family. Mutations in different splicing factor-encoding genes were identified in retinitis pigmentosa (RP) patients. A surprising feature of these ubiquitous factors is that the outcome of their alteration is restricted to the retina. Because of their high metabolic demand, most studies focused on photoreceptors dysfunction and associated degeneration. However, cells from the retinal pigment epithelium (RPE) are also crucial to maintaining retinal homeostasis and photoreceptor function. Moreover, mutations in RPE-specific genes are associated with some RP cases. Indeed, we identified major RPE defects in Prpf31-mutant mice: circadian rhythms of both photoreceptor outer segments (POS) phagocytosis and retinal adhesion were attenuated or lost, leading to ultrastructural anomalies and vacuoles. Taken together, our published and ongoing data suggest that (1) similar molecular events take place in human and mouse cells and (2) these functional defects generate various stress processes.
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Affiliation(s)
- Abdallah Hamieh
- Therapeutics Department, Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Emeline F Nandrot
- Therapeutics Department, Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.
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16
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Mutation spectrum of PRPF31, genotype-phenotype correlation in retinitis pigmentosa, and opportunities for therapy. Exp Eye Res 2020; 192:107950. [PMID: 32014492 PMCID: PMC7065041 DOI: 10.1016/j.exer.2020.107950] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/13/2020] [Accepted: 01/27/2020] [Indexed: 12/11/2022]
Abstract
Pathogenic variants in pre-messenger RNA (pre-mRNA) splicing factor 31, PRPF31, are the second most common genetic cause of autosomal dominant retinitis pigmentosa (adRP) in most populations. This remains a completely untreatable and incurable form of blindness, and it can be difficult to predict the clinical course of disease. In order to design appropriate targeted therapies, a thorough understanding of the genetics and molecular mechanism of this disease is required. Here, we present the structure of the PRPF31 gene and PRPF31 protein, current understanding of PRPF31 protein function and the full spectrum of all reported clinically relevant variants in PRPF31. We delineate the correlation between specific PRPF31 genotype and RP phenotype, suggesting that, except in cases of complete gene deletion or large-scale deletions, dominant negative effects contribute to phenotype as well as haploinsufficiency. This has important impacts on design of targeted therapies, particularly the feasibility of gene augmentation as a broad approach for treatment of PRPF31-associated RP. We discuss other opportunities for therapy, including antisense oligonucleotide therapy and gene-independent approaches and offer future perspectives on treatment of this form of RP. PRPF31 is the second most common cause of autosomal dominant retinitis pigmentosa and a potential target for gene therapy. We present all reported pathogenic variants in PRPF31 as a resource for clinicians, diagnostic genetics labs, and researchers. Genotype-phenotype correlations suggest that, dominant negative effects contribute to disease in addition to haploinsufficiency. This finding has important impacts on the suitability of gene augmentation approaches across all mutation types. This finding may aid prognosis of disease in PRPF31-associated RP patients.
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Evans HT, Bodea LG, Götz J. Cell-specific non-canonical amino acid labelling identifies changes in the de novo proteome during memory formation. eLife 2020; 9:e52990. [PMID: 31904341 PMCID: PMC6944461 DOI: 10.7554/elife.52990] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/13/2019] [Indexed: 12/15/2022] Open
Abstract
The formation of spatial long-term memory (LTM) requires the de novo synthesis of distinct sets of proteins; however, a non-biased examination of the de novo proteome in this process is lacking. Here, we generated a novel mouse strain, which enables cell-type-specific labelling of newly synthesised proteins with non-canonical amino acids (NCAAs) by genetically restricting the expression of the mutant tRNA synthetase, NLL-MetRS, to hippocampal neurons. By combining this labelling technique with an accelerated version of the active place avoidance task and bio-orthogonal non-canonical amino acid tagging (BONCAT) followed by SWATH quantitative mass spectrometry, we identified 156 proteins that were altered in synthesis in hippocampal neurons during spatial memory formation. In addition to observing increased synthesis of known proteins important in memory-related processes, such as glutamate receptor recycling, we also identified altered synthesis of proteins associated with mRNA splicing as a potential mechanism involved in spatial LTM formation.
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Affiliation(s)
- Harrison Tudor Evans
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain InstituteThe University of QueenslandBrisbaneAustralia
| | - Liviu-Gabriel Bodea
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain InstituteThe University of QueenslandBrisbaneAustralia
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain InstituteThe University of QueenslandBrisbaneAustralia
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18
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Valdés-Sánchez L, Calado SM, de la Cerda B, Aramburu A, García-Delgado AB, Massalini S, Montero-Sánchez A, Bhatia V, Rodríguez-Bocanegra E, Diez-Lloret A, Rodríguez-Martínez D, Chakarova C, Bhattacharya SS, Díaz-Corrales FJ. Retinal pigment epithelium degeneration caused by aggregation of PRPF31 and the role of HSP70 family of proteins. Mol Med 2019; 26:1. [PMID: 31892304 PMCID: PMC6938640 DOI: 10.1186/s10020-019-0124-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 12/05/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Mutations in pre-mRNA splicing factor PRPF31 can lead to retinitis pigmentosa (RP). Although the exact disease mechanism remains unknown, it has been hypothesized that haploinsufficiency might be involved in the pathophysiology of the disease. METHODS In this study, we have analyzed a mouse model containing the p.A216P mutation in Prpf31 gene. RESULTS We found that mutant Prpf31 protein produces cytoplasmic aggregates in the retinal pigment epithelium and decreasing the protein levels of this splicing factor in the nucleus. Additionally, normal protein was recruited in insoluble aggregates when the mutant protein was overexpressed in vitro. In response to protein aggregation, Hspa4l is overexpressed. This member of the HSP70 family of chaperones might contribute to the correct folding and solubilization of the mutant protein, allowing its translocation to the nucleus. CONCLUSIONS Our data suggests that a mechanism haploinsufficiency and dominant-negative is involved in retinal degeneration due to mutations in PRPF31. HSP70 over-expression might be a new therapeutic target for the treatment of retinal degeneration due to PRPF31 mutations.
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Affiliation(s)
- Lourdes Valdés-Sánchez
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Sofia M Calado
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Center for Biomedical Research (CBMR), University of Algarve, 8800-139, Faro, Portugal
| | - Berta de la Cerda
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Ana Aramburu
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Clinique de l'Oeil, Avenue Bois de la Chapelle 15, 1213, Onex, Switzerland
| | - Ana Belén García-Delgado
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Simone Massalini
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Center for Molecular and Cellular Bioengineering (CMCB) DFG-Research Center for Regenerative Therapies Dresden (CRTD) Cluster of Excellence, Technische Universität Dresden, Fetscherstraße, 105 01307, Dresden, Germany
| | - Adoración Montero-Sánchez
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Vaibhav Bhatia
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Eduardo Rodríguez-Bocanegra
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Universitätsklinikum Tübingen, Forschungsinstitut für Augenheilkunde, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Germany
| | - Andrea Diez-Lloret
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Daniel Rodríguez-Martínez
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Christina Chakarova
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Shom S Bhattacharya
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
| | - Francisco J Díaz-Corrales
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain.
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Brydon EM, Bronstein R, Buskin A, Lako M, Pierce EA, Fernandez-Godino R. AAV-Mediated Gene Augmentation Therapy Restores Critical Functions in Mutant PRPF31 +/- iPSC-Derived RPE Cells. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 15:392-402. [PMID: 31890732 PMCID: PMC6909184 DOI: 10.1016/j.omtm.2019.10.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/28/2019] [Indexed: 12/12/2022]
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited vision loss and is characterized by degeneration of retinal photoreceptor cells and the retinal pigment epithelium (RPE). Mutations in pre-mRNA processing factor 31 (PRPF31) cause dominant RP via haploinsufficiency with incomplete penetrance. There is good evidence that the diverse severity of this disease is a result of differing levels of expression of the wild-type allele among patients. Thus, we hypothesize that PRPF31-related RP will be amenable to treatment by adeno-associated virus (AAV)-mediated gene augmentation therapy. To test this hypothesis, we used induced pluripotent stem cells (iPSCs) with mutations in PRPF31 and differentiated them into RPE cells. The mutant PRPF31 iPSC-RPE cells recapitulate the cellular phenotype associated with the PRPF31 pathology, including defective cell structure, diminished phagocytic function, defects in ciliogenesis, and compromised barrier function. Treatment of the mutant PRPF31 iPSC-RPE cells with AAV-PRPF31 restored normal phagocytosis and cilia formation, and it partially restored structure and barrier function. These results suggest that AAV-based gene therapy targeting RPE cells holds therapeutic promise for patients with PRPF31-related RP.
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Affiliation(s)
- Elizabeth M Brydon
- Department of Ophthalmology, Ocular Genomics Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Revital Bronstein
- Department of Ophthalmology, Ocular Genomics Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Adriana Buskin
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Eric A Pierce
- Department of Ophthalmology, Ocular Genomics Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Rosario Fernandez-Godino
- Department of Ophthalmology, Ocular Genomics Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
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Wheway G, Nazlamova L, Meshad N, Hunt S, Jackson N, Churchill A. A Combined in silico, in vitro and Clinical Approach to Characterize Novel Pathogenic Missense Variants in PRPF31 in Retinitis Pigmentosa. Front Genet 2019; 10:248. [PMID: 30967900 PMCID: PMC6438860 DOI: 10.3389/fgene.2019.00248] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 03/05/2019] [Indexed: 11/30/2022] Open
Abstract
At least six different proteins of the spliceosome, including PRPF3, PRPF4, PRPF6, PRPF8, PRPF31, and SNRNP200, are mutated in autosomal dominant retinitis pigmentosa (adRP). These proteins have recently been shown to localize to the base of the connecting cilium of the retinal photoreceptor cells, elucidating this form of RP as a retinal ciliopathy. In the case of loss-of-function variants in these genes, pathogenicity can easily be ascribed. In the case of missense variants, this is more challenging. Furthermore, the exact molecular mechanism of disease in this form of RP remains poorly understood. In this paper we take advantage of the recently published cryo EM-resolved structure of the entire human spliceosome, to predict the effect of a novel missense variant in one component of the spliceosome; PRPF31, found in a patient attending the genetics eye clinic at Bristol Eye Hospital. Monoallelic variants in PRPF31 are a common cause of autosomal dominant retinitis pigmentosa (adRP) with incomplete penetrance. We use in vitro studies to confirm pathogenicity of this novel variant PRPF31 c.341T > A, p.Ile114Asn. This work demonstrates how in silico modeling of structural effects of missense variants on cryo-EM resolved protein complexes can contribute to predicting pathogenicity of novel variants, in combination with in vitro and clinical studies. It is currently a considerable challenge to assign pathogenic status to missense variants in these proteins.
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Affiliation(s)
- Gabrielle Wheway
- Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - Liliya Nazlamova
- Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - Nervine Meshad
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Samantha Hunt
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Nicola Jackson
- Clinical Genetics Service, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Amanda Churchill
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
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21
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Mountford JK, Davies WIL, Griffiths LR, Yazar S, Mackey DA, Hunt DM. Differential stability of variant OPN1LW gene transcripts in myopic patients. Mol Vis 2019; 25:183-193. [PMID: 30996587 PMCID: PMC6441357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 03/15/2019] [Indexed: 11/03/2022] Open
Abstract
Purpose In Bornholm eye disease, a defect in the splicing of transcripts from a variant OPN1LW opsin gene leads to a depletion in spliced transcript levels and, consequently, a reduction in photopigment in photoreceptors expressing the variant gene. Methods Myopic and age-matched control subjects were drawn from the Western Australian Pregnancy Cohort (Raine) Study and the Norfolk Island Eye Study groups. The OPN1LW opsin gene was amplified using long-range PCR methodology and was fully sequenced. Expression of variant opsins was evaluated using quantitative PCR (qPCR). RNA secondary structure changes arising from identified variants were predicted by modeling. Results Forty-two nucleotide sites were found to vary across the 111 subjects studied. Of these, 15 had not been previously reported, with three present only in myopic individuals. Expression of these variants in transfected human embryonic kidney (HEK293T) cells demonstrated that splicing efficiencies were not affected. However, gene transcripts from two of the three variants were significantly depleted. RNA secondary structure modeling predicted that these single nucleotide changes could affect RNA stability. Conclusions None of the variants identified in myopic individuals appeared to alter the efficiency of transcript splicing. However, two resulted in a significant reduction in the number of spliced and unspliced transcripts, indicating an overall reduction in steady-state transcript stability. Such a change would be expected to result in a reduced amount of photopigment, and this may be a contributing factor in the development of myopia.
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Affiliation(s)
- Jessica K. Mountford
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia,School of Biological Sciences, University of Western Australia, Perth, WA, Australia,UWA Oceans Institute, University of Western Australia, Crawley, WA, Australia,Oceans Graduate School, University of Western Australia, Crawley, WA, Australia
| | - Wayne I. L. Davies
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia,School of Biological Sciences, University of Western Australia, Perth, WA, Australia,UWA Oceans Institute, University of Western Australia, Crawley, WA, Australia,Oceans Graduate School, University of Western Australia, Crawley, WA, Australia
| | - Lyn R. Griffiths
- Genomics Research Centre, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Seyhan Yazar
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia,MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - David A. Mackey
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia
| | - David M. Hunt
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia,School of Biological Sciences, University of Western Australia, Perth, WA, Australia
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22
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A novel mutation in the PRPF31 in a North Indian adRP family with incomplete penetrance. Doc Ophthalmol 2018; 137:103-119. [PMID: 30099644 DOI: 10.1007/s10633-018-9654-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 08/03/2018] [Indexed: 12/27/2022]
Abstract
PURPOSE To identify the underlying genetic defect for non-syndromic autosomal dominant retinitis pigmentosa (adRP) with incomplete penetrance in a North Indian family. METHODS Family history and clinical data were collected. Linkage analysis using 72 fluorescently labeled microsatellite markers flanking all the 26 candidate genes known for adRP was performed. Mutation screening in candidate gene at the mapped region was performed by bi-directional DNA sequencing. RESULTS Positive two-point lod scores > 1.0 (θ = 0.000) suggestive of linkage were obtained with markers D19S572, D19S927 and D19S926 at 19q13.42, in the vicinity of PRPF31 gene. Mutation screening in all the 14 exonic regions and intron-exon boundaries of PRPF31 revealed a novel change, i.e. c.896G>A (p.Cys299Tyr) in exon eight. The observed change segregated in heterozygous form in all the six affected members and in three carriers, consistent with incomplete penetrance. This substitution was not observed in tested 15 unaffected members and in 200 ethnically matched controls. CONCLUSION Present study describes mapping of a locus for non-syndromic adRP with incomplete penetrance at 19q13.42 in a North Indian family and identifies a novel missense mutation (p.Cys299Tyr) in PRPF31 localized at the mapped interval. The observed substitution lies in the NOP domain of PRPF31 that exhibit RNA and protein binding surfaces and thus may interfere in the formation of spliceosome complex. Due to p.Cys299Tyr substitution hydrogen bonds are generated, which may result in conformational changes and PRPF31 protein deformity. Present findings further substantiate the role of PRPF31 in adRP with incomplete penetrance and expand the mutation spectrum of PRPF31.
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23
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Long-term clinical course of 2 Japanese patients with PRPF31-related retinitis pigmentosa. Jpn J Ophthalmol 2018; 62:186-193. [PMID: 29305715 DOI: 10.1007/s10384-017-0560-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/28/2017] [Indexed: 12/17/2022]
Abstract
PURPOSE To assess the long-term clinical course of 2 patients with PRPF31-related retinitis pigmentosa (RP). PATIENTS AND METHODS We clinically examined 2 unrelated patients with RP and collected peripheral blood samples from them. Ophthalmic examinations, including best-corrected visual acuity measurements, Goldmann perimetry, full-field electroretinography, fundus autofluorescence imaging, and optical coherence tomography, were also performed. The visual acuity and visual field were continuously monitored. To identify the causative mutations, 74 genes known to cause RP or Leber congenital amaurosis were examined via targeted next-generation sequencing. RESULTS The clinical courses of both patients were similar. The onset of nyctalopia occurred in the first decade. Fundus examination showed typical RP. Although the patients' visual acuity was relatively preserved even into the fourth decade, the visual field area exhibited rapid deterioration in the mid-teens, with severe concentric constriction in the third decade. Mutation analysis revealed PRPF31 mutations as the cause for autosomal dominant RP in both patients. CONCLUSIONS To the best of our knowledge, few reports of long-term observations pertaining to patients with PRPF31-related RP have been published. The findings reported herein, especially those relating to the progressive degeneration of the visual field, may ultimately play a role in the provision of high-quality counseling for patients with this condition.
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24
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Dias MF, Joo K, Kemp JA, Fialho SL, da Silva Cunha A, Woo SJ, Kwon YJ. Molecular genetics and emerging therapies for retinitis pigmentosa: Basic research and clinical perspectives. Prog Retin Eye Res 2017; 63:107-131. [PMID: 29097191 DOI: 10.1016/j.preteyeres.2017.10.004] [Citation(s) in RCA: 248] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 10/19/2017] [Accepted: 10/25/2017] [Indexed: 02/06/2023]
Abstract
Retinitis Pigmentosa (RP) is a hereditary retinopathy that affects about 2.5 million people worldwide. It is characterized with progressive loss of rods and cones and causes severe visual dysfunction and eventual blindness in bilateral eyes. In addition to more than 3000 genetic mutations from about 70 genes, a wide genetic overlap with other types of retinal dystrophies has been reported with RP. This diversity of genetic pathophysiology makes treatment extremely challenging. Although therapeutic attempts have been made using various pharmacologic agents (neurotrophic factors, antioxidants, and anti-apoptotic agents), most are not targeted to the fundamental cause of RP, and their clinical efficacy has not been clearly proven. Current therapies for RP in ongoing or completed clinical trials include gene therapy, cell therapy, and retinal prostheses. Gene therapy, a strategy to correct the genetic defects using viral or non-viral vectors, has the potential to achieve definitive treatment by replacing or silencing a causative gene. Among many clinical trials of gene therapy for hereditary retinal diseases, a phase 3 clinical trial of voretigene neparvovec (AAV2-hRPE65v2, Luxturna) recently showed significant efficacy for RPE65-mediated inherited retinal dystrophy including Leber congenital amaurosis and RP. It is about to be approved as the first ocular gene therapy biologic product. Despite current limitations such as limited target genes and indicated patients, modest efficacy, and the invasive administration method, development in gene editing technology and novel gene delivery carriers make gene therapy a promising therapeutic modality for RP and other hereditary retinal dystrophies in the future.
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Affiliation(s)
- Marina França Dias
- School of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, Brazil; Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Kwangsic Joo
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Jessica A Kemp
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Silvia Ligório Fialho
- Pharmaceutical Research and Development, Ezequiel Dias Foundation, Belo Horizonte, Brazil
| | | | - Se Joon Woo
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA; Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
| | - Young Jik Kwon
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA; Department of Chemical Engineering and Materials Sciences, University of California, Irvine, CA, USA; Department of Biomedical Engineering, University of California, Irvine, CA, USA; Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA.
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25
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Malinová A, Cvačková Z, Matějů D, Hořejší Z, Abéza C, Vandermoere F, Bertrand E, Staněk D, Verheggen C. Assembly of the U5 snRNP component PRPF8 is controlled by the HSP90/R2TP chaperones. J Cell Biol 2017; 216:1579-1596. [PMID: 28515276 PMCID: PMC5461031 DOI: 10.1083/jcb.201701165] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/22/2017] [Accepted: 04/04/2017] [Indexed: 12/23/2022] Open
Abstract
The pre-mRNA splicing factor PRPF8 is a crucial component of the U5 snRNP. Using quantitative proteomics, Malinová et al. show that assembly of the U5 snRNP is controlled by the HSP90/R2TP chaperones and that Retinitis pigmentosa–associated mutations in PRPF8 impair PRPF8 quality control and U5 snRNP chaperone-mediated assembly. Splicing is catalyzed by the spliceosome, a complex of five major small nuclear ribonucleoprotein particles (snRNPs). The pre-mRNA splicing factor PRPF8 is a crucial component of the U5 snRNP, and together with EFTUD2 and SNRNP200, it forms a central module of the spliceosome. Using quantitative proteomics, we identified assembly intermediates containing PRPF8, EFTUD2, and SNRNP200 in association with the HSP90/R2TP complex, its ZNHIT2 cofactor, and additional proteins. HSP90 and R2TP bind unassembled U5 proteins in the cytoplasm, stabilize them, and promote the formation of the U5 snRNP. We further found that PRPF8 mutants causing Retinitis pigmentosa assemble less efficiently with the U5 snRNP and bind more strongly to R2TP, with one mutant retained in the cytoplasm in an R2TP-dependent manner. We propose that the HSP90/R2TP chaperone system promotes the assembly of a key module of U5 snRNP while assuring the quality control of PRPF8. The proteomics data further reveal new interactions between R2TP and the tuberous sclerosis complex (TSC), pointing to a potential link between growth signals and the assembly of key cellular machines.
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Affiliation(s)
- Anna Malinová
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic.,Faculty of Science, Charles University in Prague, 128 00 Prague, Czech Republic
| | - Zuzana Cvačková
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Daniel Matějů
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Zuzana Hořejší
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Claire Abéza
- Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique, University of Montpellier, 34293 Montpellier, France
| | - Franck Vandermoere
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, University of Montpellier, 34090 Montpellier, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique, University of Montpellier, 34293 Montpellier, France
| | - David Staněk
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Céline Verheggen
- Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique, University of Montpellier, 34293 Montpellier, France
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26
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Lv JN, Zhou GH, Chen X, Chen H, Wu KC, Xiang L, Lei XL, Zhang X, Wu RH, Jin ZB. Targeted RP9 ablation and mutagenesis in mouse photoreceptor cells by CRISPR-Cas9. Sci Rep 2017; 7:43062. [PMID: 28216641 PMCID: PMC5317003 DOI: 10.1038/srep43062] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 01/17/2017] [Indexed: 01/24/2023] Open
Abstract
Precursor messenger RNA (Pre-mRNA) splicing is an essential biological process in eukaryotic cells. Genetic mutations in many spliceosome genes confer human eye diseases. Mutations in the pre-mRNA splicing factor, RP9 (also known as PAP1), predispose autosomal dominant retinitis pigmentosa (adRP) with an early onset and severe vision loss. However, underlying molecular mechanisms of the RP9 mutation causing photoreceptor degeneration remains fully unknown. Here, we utilize the CRISPR/Cas9 system to generate both the Rp9 gene knockout (KO) and point mutation knock in (KI) (Rp9, c.A386T, P.H129L) which is analogous to the reported one in the retinitis pigmentosa patients (RP9, c.A410T, P.H137L) in 661 W retinal photoreceptor cells in vitro. We found that proliferation and migration were significantly decreased in the mutated cells. Gene expression profiling by RNA-Seq demonstrated that RP associated genes, Fscn2 and Bbs2, were down-regulated in the mutated cells. Furthermore, pre-mRNA splicing of the Fscn2 gene was markedly affected. Our findings reveal a functional relationship between the ubiquitously expressing RP9 and the disease-specific gene, thereafter provide a new insight of disease mechanism in RP9-related retinitis pigmentosa.
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Affiliation(s)
- Ji-Neng Lv
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Gao-Hui Zhou
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Xuejiao Chen
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Hui Chen
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Kun-Chao Wu
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Lue Xiang
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Xin-Lan Lei
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Xiao Zhang
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Rong-Han Wu
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Zi-Bing Jin
- Lab for Stem Cell &Retinal Regeneration, Institute of Stem Cell Research, The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health Wenzhou 325027, China.,Division of Ophthalmic Genetics, The Eye Hospital of Wenzhou Medical University, Wenzhou 325027, China
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Identification of an Alternative Splicing Product of the Otx2 Gene Expressed in the Neural Retina and Retinal Pigmented Epithelial Cells. PLoS One 2016; 11:e0150758. [PMID: 26985665 PMCID: PMC4795653 DOI: 10.1371/journal.pone.0150758] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 01/20/2016] [Indexed: 12/16/2022] Open
Abstract
To investigate the complexity of alternative splicing in the retina, we sequenced and analyzed a total of 115,706 clones from normalized cDNA libraries from mouse neural retina (66,217) and rat retinal pigmented epithelium (49,489). Based upon clustering the cDNAs and mapping them with their respective genomes, the estimated numbers of genes were 9,134 for the mouse neural retina and 12,050 for the rat retinal pigmented epithelium libraries. This unique collection of retinal of messenger RNAs is maintained and accessible through a web-base server to the whole community of retinal biologists for further functional characterization. The analysis revealed 3,248 and 3,202 alternative splice events for mouse neural retina and rat retinal pigmented epithelium, respectively. We focused on transcription factors involved in vision. Among the six candidates suitable for functional analysis, we selected Otx2S, a novel variant of the Otx2 gene with a deletion within the homeodomain sequence. Otx2S is expressed in both the neural retina and retinal pigmented epithelium, and encodes a protein that is targeted to the nucleus. OTX2S exerts transdominant activity on the tyrosinase promoter when tested in the physiological environment of primary RPE cells. By overexpressing OTX2S in primary RPE cells using an adeno associated viral vector, we identified 10 genes whose expression is positively regulated by OTX2S. We find that OTX2S is able to bind to the chromatin at the promoter of the retinal dehydrogenase 10 (RDH10) gene.
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28
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Vergara MN, Gutierrez C, Canto-Soler MV. Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach. J Vis Exp 2015:e52002. [PMID: 26556302 DOI: 10.3791/52002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The cone photoreceptor-enriched cultures derived from embryonic chick retinas have become an indispensable tool for researchers around the world studying the biology of retinal neurons, particularly photoreceptors. The applications of this system go beyond basic research, as they can easily be adapted to high throughput technologies for drug development. However, genetic manipulation of retinal photoreceptors in these cultures has proven to be very challenging, posing an important limitation to the usefulness of the system. We have recently developed and validated an ex ovo plasmid electroporation technique that increases the rate of transfection of retinal cells in these cultures by five-fold compared to other currently available protocols(1). In this method embryonic chick eyes are enucleated at stage 27, the RPE is removed, and the retinal cup is placed in a plasmid-containing solution and electroporated using easily constructed custom-made electrodes. The retinas are then dissociated and cultured using standard procedures. This technique can be applied to overexpression studies as well as to the downregulation of gene expression, for example via the use of plasmid-driven RNAi technology, commonly achieving transgene expression in 25% of the photoreceptor population. The video format of the present publication will make this technology easily accessible to researchers in the field, enabling the study of gene function in primary retinal cultures. We have also included detailed explanations of the critical steps of this procedure for a successful outcome and reproducibility.
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Affiliation(s)
- M Natalia Vergara
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine
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29
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Yoon CK, Kim NKD, Joung JG, Shin JY, Park JH, Eum HH, Lee HO, Park WY, Yu HG. The diagnostic application of targeted re-sequencing in Korean patients with retinitis pigmentosa. BMC Genomics 2015; 16:515. [PMID: 26155838 PMCID: PMC4496857 DOI: 10.1186/s12864-015-1723-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 06/26/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Identification of the causative genes of retinitis pigmentosa (RP) is important for the clinical care of patients with RP. However, a comprehensive genetic study has not been performed in Korean RP patients. Moreover, the genetic heterogeneity found in sensorineural genetic disorders makes identification of pathogenic mutations challenging. Therefore, high throughput genetic testing using massively parallel sequencing is needed. RESULTS Sixty-two Korean patients with nonsyndromic RP (46 patients from 18 families and 16 simplex cases) who consented to molecular genetic testing were recruited in this study and targeted exome sequencing was applied on 53 RP-related genes. Causal variants were characterised by selecting exonic and splicing variants, selecting variants with low allele frequency (below 1 %), and discarding the remaining variants with quality below 20. The variants were additionally confirmed by an inheritance pattern and cosegregation test of the families, and the rest of the variants were prioritised using in-silico prediction tools. Finally, causal variants were detected from 10 of 18 familial cases (55.5 %) and 7 of 16 simplex cases (43.7 %) in total. Novel variants were detected in 13 of 20 (65 %) candidate variants. Compound heterozygous variants were found in four of 7 simplex cases. CONCLUSION Panel-based targeted re-sequencing can be used as an effective molecular diagnostic tool for RP.
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Affiliation(s)
- Chang-Ki Yoon
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
| | - Nayoung K D Kim
- Samsung Genome Institute, Samsung Medical Center, Seoul, Korea
| | - Je-Gun Joung
- Samsung Genome Institute, Samsung Medical Center, Seoul, Korea
| | - Joo Young Shin
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
| | - Jung Hyun Park
- Department of Ophthalmology, Seoul Paik Hospital, Inje University, Seoul, Korea
| | - Hye-Hyun Eum
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea.,Samsung Genome Institute, Samsung Medical Center, Seoul, Korea
| | - Hae-Ock Lee
- Samsung Genome Institute, Samsung Medical Center, Seoul, Korea
| | - Woong-Yang Park
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Seoul, Korea. .,Samsung Genome Institute, Samsung Medical Center, Seoul, Korea.
| | - Hyeong Gon Yu
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.
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30
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Linder B, Fischer U, Gehring NH. mRNA metabolism and neuronal disease. FEBS Lett 2015; 589:1598-606. [DOI: 10.1016/j.febslet.2015.04.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/26/2015] [Accepted: 04/27/2015] [Indexed: 12/12/2022]
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31
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Nash BM, Wright DC, Grigg JR, Bennetts B, Jamieson RV. Retinal dystrophies, genomic applications in diagnosis and prospects for therapy. Transl Pediatr 2015; 4:139-63. [PMID: 26835369 PMCID: PMC4729094 DOI: 10.3978/j.issn.2224-4336.2015.04.03] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Retinal dystrophies (RDs) are degenerative diseases of the retina which have marked clinical and genetic heterogeneity. Common presentations among these disorders include night or colour blindness, tunnel vision and subsequent progression to complete blindness. The known causative disease genes have a variety of developmental and functional roles with mutations in more than 120 genes shown to be responsible for the phenotypes. In addition, mutations within the same gene have been shown to cause different disease phenotypes, even amongst affected individuals within the same family highlighting further levels of complexity. The known disease genes encode proteins involved in retinal cellular structures, phototransduction, the visual cycle, and photoreceptor structure or gene regulation. This review aims to demonstrate the high degree of genetic complexity in both the causative disease genes and their associated phenotypes, highlighting the more common clinical manifestation of retinitis pigmentosa (RP). The review also provides insight to recent advances in genomic molecular diagnosis and gene and cell-based therapies for the RDs.
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Affiliation(s)
- Benjamin M Nash
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Dale C Wright
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - John R Grigg
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Bruce Bennetts
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Robyn V Jamieson
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
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32
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Pan X, Chen X, Liu X, Gao X, Kang X, Xu Q, Chen X, Zhao K, Zhang X, Chu Q, Wang X, Zhao C. Mutation analysis of pre-mRNA splicing genes in Chinese families with retinitis pigmentosa. Mol Vis 2014; 20:770-9. [PMID: 24940031 PMCID: PMC4043610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 05/30/2014] [Indexed: 10/24/2022] Open
Abstract
PURPOSE Seven genes involved in precursor mRNA (pre-mRNA) splicing have been implicated in autosomal dominant retinitis pigmentosa (adRP). We sought to detect mutations in all seven genes in Chinese families with RP, to characterize the relevant phenotypes, and to evaluate the prevalence of mutations in splicing genes in patients with adRP. METHODS Six unrelated families from our adRP cohort (42 families) and two additional families with RP with uncertain inheritance mode were clinically characterized in the present study. Targeted sequence capture with next-generation massively parallel sequencing (NGS) was performed to screen mutations in 189 genes including all seven pre-mRNA splicing genes associated with adRP. Variants detected with NGS were filtered with bioinformatics analyses, validated with Sanger sequencing, and prioritized with pathogenicity analysis. RESULTS Mutations in pre-mRNA splicing genes were identified in three individual families including one novel frameshift mutation in PRPF31 (p.Leu366fs*1) and two known mutations in SNRNP200 (p.Arg681His and p.Ser1087Leu). The patients carrying SNRNP200 p.R681H showed rapid disease progression, and the family carrying p.S1087L presented earlier onset ages and more severe phenotypes compared to another previously reported family with p.S1087L. In five other families, we identified mutations in other RP-related genes, including RP1 p. Ser781* (novel), RP2 p.Gln65* (novel) and p.Ile137del (novel), IMPDH1 p.Asp311Asn (recurrent), and RHO p.Pro347Leu (recurrent). CONCLUSIONS Mutations in splicing genes identified in the present and our previous study account for 9.5% in our adRP cohort, indicating the important role of pre-mRNA splicing deficiency in the etiology of adRP. Mutations in the same splicing gene, or even the same mutation, could correlate with different phenotypic severities, complicating the genotype-phenotype correlation and clinical prognosis.
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Affiliation(s)
- Xinyuan Pan
- Department of Ophthalmology of the First Affiliated Hospital and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Xue Chen
- Department of Ophthalmology of the First Affiliated Hospital and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Xiaoxing Liu
- Department of Ophthalmology of the First Affiliated Hospital and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Xiang Gao
- Department of Ophthalmology, Jiaozuo Health College, Henan, China
| | - Xiaoli Kang
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qihua Xu
- Department of Ophthalmology of the First Affiliated Hospital and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Xuejuan Chen
- Department of Ophthalmology of the First Affiliated Hospital and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Kanxing Zhao
- Tianjin Medical University, Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin, China
| | - Xiumei Zhang
- Department of Ophthalmology, Jiaozuo Health College, Henan, China
| | - Qiaomei Chu
- Department of Ophthalmology, Liqun Hospital, Shanghai, China
| | - Xiuying Wang
- Department of Ophthalmology of the First Affiliated Hospital and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Chen Zhao
- Department of Ophthalmology of the First Affiliated Hospital and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
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Chen X, Liu Y, Sheng X, Tam POS, Zhao K, Chen X, Rong W, Liu Y, Liu X, Pan X, Chen LJ, Zhao Q, Vollrath D, Pang CP, Zhao C. PRPF4 mutations cause autosomal dominant retinitis pigmentosa. Hum Mol Genet 2014; 23:2926-39. [PMID: 24419317 DOI: 10.1093/hmg/ddu005] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Retinitis pigmentosa (RP), a disease characterized by progressive loss of photoreceptors, exhibits significant genetic heterogeneity. Several genes associated with U4/U6-U5 triple small nuclear ribonucleoprotein (tri-snRNP) complex of the spliceosome have been implicated in autosomal dominant RP (adRP). HPrp4, encoded by PRPF4, regulates the stability of U4/U6 di-snRNP, which is essential for continuous splicing. Here, we identified two heterozygous variants in PRPF4, including c.-114_-97del in a simplex RP patient and c.C944T (p.Pro315Leu), which co-segregates with disease phenotype in a family with adRP. Both variants were absent in 400 unrelated controls. The c.-114_-97del, predicted to affect two transcription factor binding sites, was shown to down-regulate the promoter activity of PRPF4 by a luciferase assay, and was associated with a significant reduction of PRPF4 expression in the blood cells of the patient. In fibroblasts from an affected individual with the p.Pro315Leu variant, the expression levels of several tri-snRNP components, including PRPF4 itself, were up-regulated, with altered expression pattern of SC35, a spliceosome marker. The same alterations were also observed in cells over expressing hPrp4(Pro315Leu), suggesting that they arose as a compensatory response to a compromised splicing mechanism caused by hPrp4 dysfunction. Further, over expression of hPrp4(Pro315Leu), but not hPrp4(WT), triggered systemic deformities in wild-type zebrafish embryos with the retina primarily affected, and dramatically augmented death rates in morphant embryos, in which orthologous zebrafish prpf4 gene was silenced. We conclude that mutations of PRPF4 cause RP via haploinsufficiency and dominant-negative effects, and establish PRPF4 as a new U4/U6-U5 snRNP component associated with adRP.
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Affiliation(s)
- Xue Chen
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
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Xiong B, Bellen HJ. Rhodopsin homeostasis and retinal degeneration: lessons from the fly. Trends Neurosci 2013; 36:652-60. [PMID: 24012059 DOI: 10.1016/j.tins.2013.08.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/02/2013] [Accepted: 08/12/2013] [Indexed: 11/16/2022]
Abstract
Rhodopsins (Rh) are G protein-coupled receptors that function as light-sensors in photoreceptors. In humans, Rh mutations cause retinitis pigmentosa (RP), a degenerative disease that ultimately results in blindness. Studies in Drosophila have provided many insights into basic Rh biology and have identified pathways that lead to retinal degeneration. It has been shown that, because Rh is very abundant in photoreceptors, its accumulation in numerous organelles induces severe stress and results in degeneration of these cells. Moreover, genetic lesions that affect proper activation of membrane-bound Rh lead to disruption in Ca(2+) homeostasis which also causes photoreceptor degeneration. We review here the molecular signals involved in Rh homeostasis and the mechanisms underlying retinal degeneration in flies, and discuss possible links to human diseases.
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Affiliation(s)
- Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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Feng D, Xie J. Aberrant splicing in neurological diseases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:631-49. [PMID: 23821330 DOI: 10.1002/wrna.1184] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 06/03/2013] [Accepted: 06/04/2013] [Indexed: 12/12/2022]
Abstract
Splicing of precursor messenger RNA (pre-mRNA) removes the intervening sequences (introns) and joins the expressed regions (exons) in the nucleus, before an intron-containing eukaryotic mRNA transcript can be exported and translated into proteins in the cytoplasm. While some sequences are always included or excluded (constitutive splicing), others can be selectively used (alternative splicing) in this process. Particularly by alternative splicing, up to tens of thousands of variant transcripts can be produced from a single gene, which contributes greatly to the proteomic diversity for such complex cellular functions as 'wiring' neurons in the nervous system. Disruption of this process leads to aberrant splicing, which accounts for the defects of up to 50% of mutations that cause certain human genetic diseases. In this review, we describe the different mechanisms of aberrant splicing that cause or have been associated with neurological diseases.
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Affiliation(s)
- Dairong Feng
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Liu MM, Zack DJ. Alternative splicing and retinal degeneration. Clin Genet 2013; 84:142-9. [PMID: 23647439 DOI: 10.1111/cge.12181] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 04/30/2013] [Accepted: 04/30/2013] [Indexed: 12/27/2022]
Abstract
Alternative splicing is highly regulated in tissue-specific and development-specific patterns, and it has been estimated that 15% of disease-causing point mutations affect pre-mRNA splicing. In this review, we consider the cis-acting splice site and trans-acting splicing factor mutations that affect pre-mRNA splicing and contribute to retinal degeneration. Numerous splice site mutations have been identified in retinitis pigmentosa (RP) and various cone-rod dystrophies. Mutations in alternatively spliced retina-specific exons of the widely expressed RPGR and COL2A1 genes lead primarily to X-linked RP and ocular variants of Stickler syndrome, respectively. Furthermore, mutations in general pre-mRNA splicing factors, such as PRPF31, PRPF8, and PRPF3, predominantly cause autosomal dominant RP. These findings suggest an important role for pre-mRNA splicing in retinal homeostasis and the pathogenesis of retinal degenerative diseases. The development of novel therapeutic strategies to modulate aberrant splicing, including small molecule-based therapies, has the potential to lead to new treatments for retinal degenerative diseases.
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Affiliation(s)
- M M Liu
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
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Vincent AL, Carroll J, Fishman GA, Sauer A, Sharp D, Summerfelt P, Williams V, Dubis AM, Kohl S, Wong F. Rhodopsin F45L Allele Does Not Cause Autosomal Dominant Retinitis Pigmentosa in a Large Caucasian Family. Transl Vis Sci Technol 2013; 2:4. [PMID: 24049715 DOI: 10.1167/tvst.2.2.4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 01/24/2013] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To ascertain the potential pathogenicity of a retinitis pigmentosa (RP)-causing RHO F45L allele in a family affected by congenital achromatopsia (ACHM). METHODS Case series/observational study that included two patients with ACHM and 24 extended family members. Molecular genetic analysis was performed to identify RHO F45L carrier status in the family and a control population. An adaptive optics scanning light ophthalmoscope (AOSLO) was used to image the photoreceptor mosaic and assess rod and cone structure. Spectral domain optical coherence tomography (SD-OCT) was used to examine retinal lamination. Comprehensive clinical testing included acuity, color vision, and dilated fundus examination. Electroretinography was used to assess rod and cone function. RESULTS Five carriers of the RHO F45L allele alone (24-80 years) and three carriers in combination with a heterozygous CNGA3 mutant allele (10-64 years) were all free of the classic symptoms and signs of RP. In heterozygous carriers of both mutations, SD-OCT showed normal retinal thickness and intact outer retinal layers; rod and cone densities were within normal limits on AOSLO. The phenotype in two individuals affected with ACHM and harboring the RHO F45L allele was indistinguishable from that previously reported for ACHM. CONCLUSIONS The RHO F45L allele is not pathogenic in this large family; hence, the two ACHM patients would unlikely develop RP in the future. TRANSLATIONAL RELEVANCE The combined approach of comprehensive molecular analysis of individual genomes and noninvasive cellular resolution retinal imaging enhances the current repertoire of clinical diagnostic tools, giving a substantial impetus to personalized medicine.
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Affiliation(s)
- Andrea L Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand ; Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
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Ex vivo electroporation of retinal cells: a novel, high efficiency method for functional studies in primary retinal cultures. Exp Eye Res 2013; 109:40-50. [PMID: 23370269 DOI: 10.1016/j.exer.2013.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/17/2012] [Accepted: 01/19/2013] [Indexed: 11/22/2022]
Abstract
Primary retinal cultures constitute valuable tools not only for basic research on retinal cell development and physiology, but also for the identification of factors or drugs that promote cell survival and differentiation. In order to take full advantage of the benefits of this system it is imperative to develop efficient and reliable techniques for the manipulation of gene expression. However, achieving appropriate transfection efficiencies in these cultures has remained challenging. The purpose of this work was to develop and optimize a technique that would allow the transfection of chick retinal cells with high efficiency and reproducibility for multiple applications. We developed an ex vivo electroporation method applied to dissociated retinal cell cultures that offers a significant improvement over other currently available transfection techniques, increasing efficiency by five-fold. In this method, eyes were enucleated, devoid of RPE, and electroporated with GFP-encoding plasmids using custom-made electrodes. Electroporated retinas were then dissociated into single cells and plated in low density conditions, to be analyzed after 4 days of incubation. Parameters such as voltage and number of electric pulses, as well as plasmid concentration and developmental stage of the animal were optimized for efficiency. The characteristics of the cultures were assessed by morphology and immunocytochemistry, and cell viability was determined by ethidium homodimer staining. Cell imaging and counting was performed using an automated high-throughput system. This procedure resulted in transfection efficiencies in the order of 22-25% of cultured cells, encompassing both photoreceptors and non-photoreceptor neurons, and without affecting normal cell survival and differentiation. Finally, the feasibility of the technique for cell-autonomous studies of gene function in a biologically relevant context was tested by carrying out gain and loss-of-function experiments for the transcription factor PAX6. Electroporation of a plasmid construct expressing PAX6 resulted in a marked upregulation in the expression levels of this protein that could be measured in the whole culture as well as cell-intrinsically. This was accompanied by a significant decrease in the percentage of cells differentiating as photoreceptors among the transfected population. Conversely, electroporation of an RNAi construct targeting PAX6 resulted in a significant decrease in the levels of this protein, with a concomitant increase in the proportion of photoreceptors. Taken together these results provide strong proof-of-principle of the suitability of this technique for genetic studies in retinal cultures. The combination of the high transfection efficiency obtained by this method with automated high-throughput cell analysis supplies the scientific community with a powerful system for performing functional studies in a cell-autonomous manner.
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Yin J, Brocher J, Fischer U, Winkler C. Mutant Prpf31 causes pre-mRNA splicing defects and rod photoreceptor cell degeneration in a zebrafish model for Retinitis pigmentosa. Mol Neurodegener 2011; 6:56. [PMID: 21801444 PMCID: PMC3158551 DOI: 10.1186/1750-1326-6-56] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 07/30/2011] [Indexed: 11/21/2022] Open
Abstract
Background Retinitis pigmentosa (RP) is an inherited eye disease characterized by the progressive degeneration of rod photoreceptor cells. Mutations in pre-mRNA splicing factors including PRPF31 have been identified as cause for RP, raising the question how mutations in general factors lead to tissue specific defects. Results We have recently shown that the zebrafish serves as an excellent model allowing the recapitulation of key events of RP. Here we use this model to investigate two pathogenic mutations in PRPF31, SP117 and AD5, causing the autosomal dominant form of RP. We show that SP117 leads to an unstable protein that is mislocalized to the rod cytoplasm. Importantly, its overexpression does not result in photoreceptor degeneration suggesting haploinsufficiency as the underlying cause in human RP patients carrying SP117. In contrast, overexpression of AD5 results in embryonic lethality, which can be rescued by wild-type Prpf31. Transgenic retina-specific expression of AD5 reveals that stable AD5 protein is initially localized in the nucleus but later found in the cytoplasm concurrent with progressing rod outer segment degeneration and apoptosis. Importantly, we show for the first time in vivo that retinal transcripts are wrongly spliced in adult transgenic retinas expressing AD5 and exhibiting increased apoptosis in rod photoreceptors. Conclusion Our data suggest that distinct mutations in Prpf31 can lead to photoreceptor degeneration through different mechanisms, by haploinsufficiency or dominant-negative effects. Analyzing the AD5 effects in our animal model in vivo, our data imply that aberrant splicing of distinct retinal transcripts contributes to the observed retina defects.
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Affiliation(s)
- Jun Yin
- Department of Biological Sciences; National University of Singapore; 117543, Singapore.
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Wan J, Masuda T, Hackler L, Torres KM, Merbs SL, Zack DJ, Qian J. Dynamic usage of alternative splicing exons during mouse retina development. Nucleic Acids Res 2011; 39:7920-30. [PMID: 21724604 PMCID: PMC3185435 DOI: 10.1093/nar/gkr545] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Alternative processing of pre-mRNA plays an important role in protein diversity and biological function. Previous studies on alternative splicing (AS) often focused on the spatial patterns of protein isoforms across different tissues. Here we studied dynamic usage of AS across time, during murine retina development. Over 7000 exons showed dynamical changes in splicing, with differential splicing events occurring more frequently in early development. The overall splicing patterns for exclusive and inclusive exons show symmetric trends and genes with symmetric splicing patterns that tend to have similar biological functions. Furthermore, we observed that within the retina, retina-enriched genes that are preferentially expressed at the adult stage tend to have more dynamically spliced exons compared to other genes, suggesting that genes maintaining retina homeostasis also play an important role in development via a series of AS events. Interestingly, the transcriptomes of retina-enriched genes largely reflect the retinal developmental process. Finally, we identified a number of candidate cis-regulatory elements for retinal AS by analyzing the relative occurrence of sequence motifs in exons or flanking introns. The occurrence of predicted regulatory elements showed strong correlation with the expression level of known RNA binding proteins, suggesting the high quality of the identified cis-regulatory elements.
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Affiliation(s)
- Jun Wan
- Wilmer Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Tanackovic G, Ransijn A, Thibault P, Abou Elela S, Klinck R, Berson EL, Chabot B, Rivolta C. PRPF mutations are associated with generalized defects in spliceosome formation and pre-mRNA splicing in patients with retinitis pigmentosa. Hum Mol Genet 2011; 20:2116-30. [PMID: 21378395 PMCID: PMC3090192 DOI: 10.1093/hmg/ddr094] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/08/2011] [Accepted: 03/01/2011] [Indexed: 01/22/2023] Open
Abstract
Proteins PRPF31, PRPF3 and PRPF8 (RP-PRPFs) are ubiquitously expressed components of the spliceosome, a macromolecular complex that processes nearly all pre-mRNAs. Although these spliceosomal proteins are conserved in eukaryotes and are essential for survival, heterozygous mutations in human RP-PRPF genes lead to retinitis pigmentosa, a hereditary disease restricted to the eye. Using cells from patients with 10 different mutations, we show that all clinically relevant RP-PRPF defects affect the stoichiometry of spliceosomal small nuclear RNAs (snRNAs), the protein composition of tri-small nuclear ribonucleoproteins and the kinetics of spliceosome assembly. These mutations cause inefficient splicing in vitro and affect constitutive splicing ex-vivo by impairing the removal of at least 9% of endogenously expressed introns. Alternative splicing choices are also affected when RP-PRPF defects are present. Furthermore, we show that the steady-state levels of snRNAs and processed pre-mRNAs are highest in the retina, indicating a particularly elevated splicing activity. Our results suggest a role for PRPFs defects in the etiology of PRPF-linked retinitis pigmentosa, which appears to be a truly systemic splicing disease. Although these mutations cause widespread and important splicing defects, they are likely tolerated by the majority of human tissues but are critical for retinal cell survival.
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Affiliation(s)
- Goranka Tanackovic
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland
| | - Adriana Ransijn
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland
| | - Philippe Thibault
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
| | - Sherif Abou Elela
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, CanadaJ1H 5N4 and
| | - Roscoe Klinck
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
| | - Eliot L. Berson
- The Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Benoit Chabot
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, CanadaJ1H 5N4 and
| | - Carlo Rivolta
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland
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Graziotto JJ, Farkas MH, Bujakowska K, Deramaudt BM, Zhang Q, Nandrot EF, Inglehearn CF, Bhattacharya SS, Pierce EA. Three gene-targeted mouse models of RNA splicing factor RP show late-onset RPE and retinal degeneration. Invest Ophthalmol Vis Sci 2011; 52:190-8. [PMID: 20811066 DOI: 10.1167/iovs.10-5194] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Mutations in genes that produce proteins involved in mRNA splicing, including pre-mRNA processing factors 3, 8, and 31 (PRPF3, 8, and 31), RP9, and SNRNP200 are common causes of the late-onset inherited blinding disorder retinitis pigmentosa (RP). It is not known how mutations in these ubiquitously expressed genes lead to retina-specific disease. To investigate the pathogenesis of the RNA splicing factor forms of RP, the authors generated and characterized the retinal phenotypes of Prpf3-T494M, Prpf8-H2309P knockin mice. The retinal ultrastructure of Prpf31-knockout mice was also investigated. METHODS The knockin mice have single codon alterations in their endogenous Prpf3 and Prpf8 genes that mimic the most common disease causing mutations in human PRPF3 and PRPF8. The Prpf31-knockout mice mimic the null alleles that result from the majority of mutations identified in PRPF31 patients. The retinal phenotypes of the gene targeted mice were evaluated by electroretinography (ERG), light, and electron microscopy. RESULTS The RPE cells of heterozygous Prpf3(+/T494M) and Prpf8(+/H2309P) knockin mice exhibited loss of the basal infoldings and vacuolization, with accumulation of amorphous deposits between the RPE and Bruch[b]'s membrane at age two years. These changes were more severe in the homozygous mice, and were associated with decreased rod function in the Prpf3-T494M mice. Similar degenerative changes in the RPE were detected in Prpf31(±) mice at one year of age. CONCLUSIONS The finding of similar degenerative changes in RPE cells of all three mouse models suggests that the RPE may be the primary cell type affected in the RNA splicing factor forms of RP. The relatively late-onset phenotype observed in these mice is consistent with the typical adult onset of disease in patients with RP.
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Affiliation(s)
- John J Graziotto
- University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Gao Y, Yang K, Xu S, Wang C, Liu J, Zhang Z, Yuan M, Luo X, Liu M, Wang QK, Liu JY. Identification of compound heterozygous mutations in GNPTG in three siblings of a Chinese family with mucolipidosis type III gamma. Mol Genet Metab 2011; 102:107-9. [PMID: 20951619 DOI: 10.1016/j.ymgme.2010.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Accepted: 09/18/2010] [Indexed: 10/19/2022]
Abstract
Mucolipidosis III gamma is an autosomal recessive disorder with defective phosphorylation and trafficking of lysosomal enzymes. In a Chinese family with three siblings, linkage analysis revealed positive linkage of the family to GNPTG. Direct DNA sequence analysis identified two novel compound heterozygous mutations, c.471delC in exon 7 and IVS4-1G>C, in three patients. The two mutations cause frameshift and abnormal splicing, respectively, and represent the first series of GNPTG mutations in the Chinese population.
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Affiliation(s)
- Yong Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Center for Human Genome Research, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
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Audo I, Bujakowska K, Mohand-Saïd S, Lancelot ME, Moskova-Doumanova V, Waseem NH, Antonio A, Sahel JA, Bhattacharya SS, Zeitz C. Prevalence and novelty of PRPF31 mutations in French autosomal dominant rod-cone dystrophy patients and a review of published reports. BMC MEDICAL GENETICS 2010; 11:145. [PMID: 20939871 PMCID: PMC2984399 DOI: 10.1186/1471-2350-11-145] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 10/12/2010] [Indexed: 12/01/2022]
Abstract
Background Rod-cone dystrophies are heterogeneous group of inherited retinal disorders both clinically and genetically characterized by photoreceptor degeneration. The mode of inheritance can be autosomal dominant, autosomal recessive or X-linked. The purpose of this study was to identify mutations in one of the genes, PRPF31, in French patients with autosomal dominant RP, to perform genotype-phenotype correlations of those patients, to determine the prevalence of PRPF31 mutations in this cohort and to review previously identified PRPF31 mutations from other cohorts. Methods Detailed phenotypic characterization was performed including precise family history, best corrected visual acuity using the ETDRS chart, slit lamp examination, kinetic and static perimetry, full field and multifocal ERG, fundus autofluorescence imaging and optic coherence tomography. For genetic diagnosis, genomic DNA of ninety families was isolated by standard methods. The coding exons and flanking intronic regions of PRPF31 were PCR amplified, purified and sequenced in the index patient. Results We showed for the first time that 6.7% cases of a French adRP cohort have a PRPF31 mutation. We identified in total six mutations, which were all novel and not detected in ethnically matched controls. The mutation spectrum from our cohort comprises frameshift and splice site mutations. Co-segregation analysis in available family members revealed that each index patient and all affected family members showed a heterozygous mutation. In five families incomplete penetrance was observed. Most patients showed classical signs of RP with relatively preserved central vision and visual field. Conclusion Our studies extended the mutation spectrum of PRPF31 and as previously reported in other populations, it is a major cause of adRP in France.
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Ray P, Luo X, Rao EJ, Basha A, Woodruff EA, Wu JY. The splicing factor Prp31 is essential for photoreceptor development in Drosophila. Protein Cell 2010; 1:267-74. [PMID: 21203973 DOI: 10.1007/s13238-010-0035-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 02/01/2010] [Indexed: 10/19/2022] Open
Abstract
Retinitis pigmentosa is a leading cause of blindness and a progressive retinal disorder, affecting millions of people worldwide. This disease is characterized by photoreceptor degeneration, eventually leading to complete blindness. Autosomal dominant (adRP) has been associated with mutations in at least four ubiquitously expressed genes encoding pre-mRNA splicing factors-Prp3, Prp8, Prp31 and PAP1. Biological function of adRP-associated splicing factor genes and molecular mechanisms by which mutations in these genes cause cell-type specific photoreceptor degeneration in humans remain to be elucidated. To investigate the in vivo function of these adRP-associated splicing factor genes, we examined Drosophila in which expression of fly Prp31 homolog was down-regulated. Sequence analyses show that CG6876 is the likely candidate of Drosophila melanogaster Prp31 homolog (DmPrp31). Predicted peptide sequence for CG6876 shows 57% similarity to the Homo sapiens Prp31 protein (HsPrp31). Reduction of the endogenous Prp31 by RNAi-mediated knockdown specifically in the eye leads to reduction of eye size or complete absence of eyes with remarkable features of photoreceptor degeneration and recapitulates the bimodal expressivity of human Prp31 mutations in adRP patients. Such transgenic DmPrp31RNAi flies provide a useful tool for identifying genetic modifiers or interacting genes for Prp31. Expression of the human Prp31 in these animals leads to a partial rescue of the eye phenotype. Our results indicate that the Drosophila CG6876 is the fly ortholog of mammalian Prp31 gene.
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Affiliation(s)
- Payal Ray
- Department of Neurology, Northwestern University Feinberg Medical School, Chicago, IL 60611, USA
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Berger W, Kloeckener-Gruissem B, Neidhardt J. The molecular basis of human retinal and vitreoretinal diseases. Prog Retin Eye Res 2010; 29:335-75. [PMID: 20362068 DOI: 10.1016/j.preteyeres.2010.03.004] [Citation(s) in RCA: 394] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
During the last two to three decades, a large body of work has revealed the molecular basis of many human disorders, including retinal and vitreoretinal degenerations and dysfunctions. Although belonging to the group of orphan diseases, they affect probably more than two million people worldwide. Most excitingly, treatment of a particular form of congenital retinal degeneration is now possible. A major advantage for treatment is the unique structure and accessibility of the eye and its different components, including the vitreous and retina. Knowledge of the many different eye diseases affecting retinal structure and function (night and colour blindness, retinitis pigmentosa, cone and cone rod dystrophies, photoreceptor dysfunctions, as well as vitreoretinal traits) is critical for future therapeutic development. We have attempted to present a comprehensive picture of these disorders, including biological, clinical, genetic and molecular information. The structural organization of the review leads the reader through non-syndromic and syndromic forms of (i) rod dominated diseases, (ii) cone dominated diseases, (iii) generalized retinal degenerations and (iv) vitreoretinal disorders, caused by mutations in more than 165 genes. Clinical variability and genetic heterogeneity have an important impact on genetic testing and counselling of affected families. As phenotypes do not always correlate with the respective genotypes, it is of utmost importance that clinicians, geneticists, counsellors, diagnostic laboratories and basic researchers understand the relationships between phenotypic manifestations and specific genes, as well as mutations and pathophysiologic mechanisms. We discuss future perspectives.
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Affiliation(s)
- Wolfgang Berger
- Division of Medical Molecular Genetics and Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland.
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Huranová M, Hnilicová J, Fleischer B, Cvacková Z, Stanek D. A mutation linked to retinitis pigmentosa in HPRP31 causes protein instability and impairs its interactions with spliceosomal snRNPs. Hum Mol Genet 2009; 18:2014-23. [PMID: 19293337 DOI: 10.1093/hmg/ddp125] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The AD29 mutation in HPRP31 belongs to a series of mutations that were initially linked with the autosomal dominant disorder retinitis pigmentosa (RP) type 11. The HPRP31 gene encodes the hPrp31 protein that specifically associates with spliceosomal small nuclear ribonucleoprotein particles (snRNPs). Despite intensive research, it is still unclear how the AD29 (Ala216Pro) mutation causes RP. In this study, we report that the expression of this mutant protein affects cell proliferation and alters the structure of nuclear Cajal bodies that are connected with snRNP metabolism. Interestingly, these effects can be reversed by the over-expression of the hPrp6 protein, a binding partner of hPrp31. Although Ala216 is not contained within the U4 or U5 snRNP interacting domains, we present several lines of evidence that demonstrate that the association between the AD29 mutant and snRNPs in the cell nucleus is significantly reduced. Finally, we show that the stability of the AD29 mutant is severely affected resulting in its rapid degradation. Taken together, our results indicate that the Ala216Pro mutation destabilizes the hPrp31 protein structure in turn reducing its interaction with snRNP binding partners and leading to its rapid degradation. These findings significantly impact our understanding of the molecular mechanisms underlying RP and suggest that the insufficiency of the functional hPrp31 protein combined with the potential cytotoxicity associated with the expression the AD29 mutant are at least partially causative of the RP phenotype.
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Affiliation(s)
- Martina Huranová
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic
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Ivings L, Towns KV, Matin M, Taylor C, Ponchel F, Grainger RJ, Ramesar RS, Mackey DA, Inglehearn CF. Evaluation of splicing efficiency in lymphoblastoid cell lines from patients with splicing-factor retinitis pigmentosa. Mol Vis 2008; 14:2357-66. [PMID: 19096719 PMCID: PMC2603472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 11/24/2008] [Indexed: 11/17/2022] Open
Abstract
PURPOSE Retinitis pigmentosa (RP) is caused by mutations in a variety of genes, most of which have known functions in the retina. However, one of the most perplexing findings of recent retinal genetics research was the discovery of mutations causing dominant RP in four ubiquitously expressed splicing factors. The aim of this study was to use lymphoblast cell lines derived from RP patients to determine whether mutations in two of these splicing factors, PRPF8 and PRPF31, cause measurable deficiencies in pre-mRNA splicing. METHODS cDNA was prepared from lymphoblastoid cell lines derived from RP patients bearing mutations in the splicing factor genes and controls, grown under a variety of conditions. Introns representing the U2 and U12 intron classes, with both canonical and noncanonical donor and acceptor sequences, were analyzed by real-time PCR to measure the ratio of spliced versus unspliced transcripts for these introns. In addition, plasmids encoding the retinal outer segment membrane protein-1 (ROM-1; exon 1 to exon 2) gene, both in the wild-type form and with mutations introduced into the splice donor sites, were transfected into cell lines. The spliced versus unspliced cDNA ratios were measured by real-time RT-PCR. RESULTS Splicing of four canonical U2 introns in the actin beta (ACTB), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), PRPF8, and retinitis pigmentosa GTPase regulator (RPGR) genes was unaffected in PRPF8 mutant cells. However, the splicing efficiency of RPGR intron 9 was significantly decreased in PRPF31 mutant cell lines. In contrast, a consistent decrease in the splicing efficiency of all U12 and noncanonical U2 introns was seen in PRPF8, but not in PRPF31, mutant cells, with statistical significance for STK11 intron 3. CONCLUSIONS In spite of the ubiquitous expression patterns of the genes implicated in splicing factor RP, no pathology has yet been documented outside the retina. The observed differences in splicing efficiency described herein favor the hypothesis that these mutations may have a subpathological effect outside the retina. These observations argue against a defect in some yet to be discovered additional function of these proteins and support the alternative hypothesis that this form of RP does indeed result from aberrant splicing of retinal transcripts.
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Affiliation(s)
- Lenka Ivings
- Section of Ophthalmology and Neuroscience, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
| | - Katherine V. Towns
- Section of Ophthalmology and Neuroscience, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
| | - M.A. Matin
- Department of Statistics, University of Leeds, Leeds, United Kingdom
| | - Charles Taylor
- Department of Statistics, University of Leeds, Leeds, United Kingdom
| | - Frederique Ponchel
- Section of Musculoskeletal Disease, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
| | - Richard J. Grainger
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Rajkumar S. Ramesar
- Department of Human Genetics, University of Cape Town Medical School, Cape Town, South Africa
| | - David A. Mackey
- CERA, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Chris F. Inglehearn
- Section of Ophthalmology and Neuroscience, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
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Abstract
The auxiliary spliceosomal protein SCNM1 contributes to recognition of nonconsensus splice donor sites. SCNM1 was first identified as a modifier of the severity of a sodium channelopathy in the mouse. The most severely affected strain, C57BL/6J, carries the variant allele SCNM1R187X, which is defective in splicing the mutated donor site in the Scn8a(medJ) transcript. To further probe the in vivo function of SCNM1, we constructed a floxed allele and generated a mouse with constitutive deletion of exons 3-5. The SCNM1Delta3-5 protein is produced and correctly localized to the nucleus, but is more functionally impaired than the C57BL/6J allele. Deficiency of SCNM1 did not significantly alter other brain transcripts. We characterized an ENU-induced allele of Scnm1 and evaluated the ability of wild-type SCNM1 to rescue lethal mutations of I-mfa and Brunol4. The phenotypes of the Scnm1Delta3-5 mutant confirm the role of this splice factor in processing the Scn8a(medJ) transcript and provide a new allele of greater severity for future studies.
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Gamundi MJ, Hernan I, Muntanyola M, Maseras M, López-Romero P, Álvarez R, Dopazo A, Borrego S, Carballo M. Transcriptional expression ofcis-acting andtrans-acting splicing mutations cause autosomal dominant retinitis pigmentosa. Hum Mutat 2008; 29:869-78. [DOI: 10.1002/humu.20747] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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