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Baz-Redón N, Sánchez-Bellver L, Fernández-Cancio M, Rovira-Amigo S, Burgoyne T, Ranjit R, Aquino V, Toro-Barrios N, Carmona R, Polverino E, Cols M, Moreno-Galdó A, Camats-Tarruella N, Marfany G. Primary Ciliary Dyskinesia and Retinitis Pigmentosa: Novel RPGR Variant and Possible Modifier Gene. Cells 2024; 13:524. [PMID: 38534367 DOI: 10.3390/cells13060524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/09/2024] [Accepted: 03/13/2024] [Indexed: 03/28/2024] Open
Abstract
We report a novel RPGR missense variant co-segregated with a familial X-linked retinitis pigmentosa (XLRP) case. The brothers were hemizygous for this variant, but only the proband presented with primary ciliary dyskinesia (PCD). Thus, we aimed to elucidate the role of the RPGR variant and other modifier genes in the phenotypic variability observed in the family and its impact on motile cilia. The pathogenicity of the variant on the RPGR protein was evaluated by in vitro studies transiently transfecting the mutated RPGR gene, and immunofluorescence analysis on nasal brushing samples. Whole-exome sequencing was conducted to identify potential modifier variants. In vitro studies showed that the mutated RPGR protein could not localise to the cilium and impaired cilium formation. Accordingly, RPGR was abnormally distributed in the siblings' nasal brushing samples. In addition, a missense variant in CEP290 was identified. The concurrent RPGR variant influenced ciliary mislocalisation of the protein. We provide a comprehensive characterisation of motile cilia in this XLRP family, with only the proband presenting PCD symptoms. The variant's pathogenicity was confirmed, although it alone does not explain the respiratory symptoms. Finally, the CEP290 gene may be a potential modifier for respiratory symptoms in patients with RPGR mutations.
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Affiliation(s)
- Noelia Baz-Redón
- Growth and Development Research Group, Vall d'Hebron Research Institute (VHIR), Hospital Universitari Vall d'Hebron, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Laura Sánchez-Bellver
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Mónica Fernández-Cancio
- Growth and Development Research Group, Vall d'Hebron Research Institute (VHIR), Hospital Universitari Vall d'Hebron, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Sandra Rovira-Amigo
- Growth and Development Research Group, Vall d'Hebron Research Institute (VHIR), Hospital Universitari Vall d'Hebron, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Department of Paediatrics, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain
| | - Thomas Burgoyne
- Royal Brompton Hospital, Guy's and St Thomas' NHS Foundation Trust, London SW3 6NP, UK
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Rai Ranjit
- Royal Brompton Hospital, Guy's and St Thomas' NHS Foundation Trust, London SW3 6NP, UK
| | - Virginia Aquino
- Plataforma Andaluza de Medicina Computacional, Fundación Pública Andaluza Progreso y Salud, 41092 Sevilla, Spain
| | - Noemí Toro-Barrios
- Plataforma Andaluza de Medicina Computacional, Fundación Pública Andaluza Progreso y Salud, 41092 Sevilla, Spain
| | - Rosario Carmona
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Plataforma Andaluza de Medicina Computacional, Fundación Pública Andaluza Progreso y Salud, 41092 Sevilla, Spain
| | - Eva Polverino
- Pneumology Research Group, Vall d'Hebron Research Institute (VHIR), Hospital Universitari Vall d'Hebron, 08035 Barcelona, Spain
- Pneumology Department, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Maria Cols
- Paediatric Pulmonology Department and Cystic Fibrosis Unit, Hospital Sant Joan de Déu, 08950 Esplugues de Llobregat, Spain
| | - Antonio Moreno-Galdó
- Growth and Development Research Group, Vall d'Hebron Research Institute (VHIR), Hospital Universitari Vall d'Hebron, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Department of Paediatrics, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain
- Department of Paediatrics, Obstetrics, Gynecology, Preventive Medicine and Public Health, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Núria Camats-Tarruella
- Growth and Development Research Group, Vall d'Hebron Research Institute (VHIR), Hospital Universitari Vall d'Hebron, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Gemma Marfany
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, 08028 Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, 08028 Barcelona, Spain
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Monson E, Cideciyan AV, Roman AJ, Sumaroka A, Swider M, Wu V, Viarbitskaya I, Jacobson SG, Fliesler SJ, Pittler SJ. Inherited Retinal Degeneration Caused by Dehydrodolichyl Diphosphate Synthase Mutation-Effect of an ALG6 Modifier Variant. Int J Mol Sci 2024; 25:1004. [PMID: 38256083 PMCID: PMC10816542 DOI: 10.3390/ijms25021004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Modern advances in disease genetics have uncovered numerous modifier genes that play a role in the severity of disease expression. One such class of genetic conditions is known as inherited retinal degenerations (IRDs), a collection of retinal degenerative disorders caused by mutations in over 300 genes. A single missense mutation (K42E) in the gene encoding the enzyme dehydrodolichyl diphosphate synthase (DHDDS), which is required for protein N-glycosylation in all cells and tissues, causes DHDDS-IRD (retinitis pigmentosa type 59 (RP59; OMIM #613861)). Apart from a retinal phenotype, however, DHDDS-IRD is surprisingly non-syndromic (i.e., without any systemic manifestations). To explore disease pathology, we selected five glycosylation-related genes for analysis that are suggested to have disease modifier variants. These genes encode glycosyltransferases (ALG6, ALG8), an ER resident protein (DDOST), a high-mannose oligosaccharyl transferase (MPDU1), and a protein N-glycosylation regulatory protein (TNKS). DNA samples from 11 confirmed DHDDS (K42E)-IRD patients were sequenced at the site of each candidate genetic modifier. Quantitative measures of retinal structure and function were performed across five decades of life by evaluating foveal photoreceptor thickness, visual acuity, foveal sensitivity, macular and extramacular rod sensitivity, and kinetic visual field extent. The ALG6 variant, (F304S), was correlated with greater macular cone disease severity and less peripheral rod disease severity. Thus, modifier gene polymorphisms may account for a significant portion of phenotypic variation observed in human genetic disease. However, the consequences of the polymorphisms may be counterintuitively complex in terms of rod and cone populations affected in different regions of the retina.
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Affiliation(s)
- Elisha Monson
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Artur V. Cideciyan
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Alejandro J. Roman
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Alexander Sumaroka
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Malgorzata Swider
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Vivian Wu
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Iryna Viarbitskaya
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Samuel G. Jacobson
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Steven J. Fliesler
- Departments of Ophthalmology and Biochemistry, and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York—University at Buffalo, Buffalo, NY 14203, USA;
- Research Service, VA Western NY Healthcare System, Buffalo, NY 14215, USA
| | - Steven J. Pittler
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
- Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Chen C, Rong Y, Zhuang Y, Tang C, Liu Q, Lin P, Li D, Zhao X, Lu F, Qu J, Liu X. RNA-Seq Analysis Reveals an Essential Role of the cGMP-PKG-MAPK Pathways in Retinal Degeneration Caused by Cep250 Deficiency. Int J Mol Sci 2023; 24:8843. [PMID: 37240188 PMCID: PMC10218315 DOI: 10.3390/ijms24108843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Usher syndrome (USH) is characterised by degenerative vision loss known as retinitis pigmentosa (RP), sensorineural hearing loss, and vestibular dysfunction. RP can cause degeneration and the loss of rod and cone photoreceptors, leading to structural and functional changes in the retina. Cep250 is a candidate gene for atypical Usher syndrome, and this study describes the development of a Cep250 KO mouse model to investigate its pathogenesis. OCT and ERG were applied in Cep250 and WT mice at P90 and P180 to access the general structure and function of the retina. After recording the ERG responses and OCT images at P90 and P180, the cone and rod photoreceptors were visualised using an immunofluorescent stain. TUNEL assays were applied to observe the apoptosis in Cep250 and WT mice retinas. The total RNA was extracted from the retinas and executed for RNA sequencing at P90. Compared with WT mice, the thickness of the ONL, IS/OS, and whole retina of Cep250 mice was significantly reduced. The a-wave and b-wave amplitude of Cep250 mice in scotopic and photopic ERG were lower, especially the a-wave. According to the immunostaining and TUNEL stain results, the photoreceptors in the Cep250 retinas were also reduced. An RNA-seq analysis showed that 149 genes were upregulated and another 149 genes were downregulated in Cep250 KO retinas compared with WT mice retinas. A KEGG enrichment analysis indicated that cGMP-PKG signalling pathways, MAPK signalling pathways, edn2-fgf2 axis pathways, and thyroid hormone synthesis were upregulated, whereas protein processing in the endoplasmic reticulum was downregulated in Cep250 KO eyes. Cep250 KO mice experience a late-stage retinal degeneration that manifests as the atypical USH phenotype. The dysregulation of the cGMP-PKG-MAPK pathways may contribute to the pathogenesis of cilia-related retinal degeneration.
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Affiliation(s)
- Chong Chen
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Yu Rong
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Youyuan Zhuang
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Cheng Tang
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Qian Liu
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Peng Lin
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Dandan Li
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Xinyi Zhao
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Fan Lu
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Jia Qu
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Xinting Liu
- National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; (C.C.); (Y.R.); (Y.Z.); (C.T.); (Q.L.); (P.L.); (D.L.); (X.Z.); (F.L.)
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
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The challenge of dissecting gene function in model organisms: Tools to characterize genetic mutants and assess transcriptional adaptation in zebrafish. Methods Cell Biol 2023; 176:1-25. [PMID: 37164532 DOI: 10.1016/bs.mcb.2022.12.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Genome editing technologies including the CRISPR/Cas9 system have greatly improved our knowledge of gene function and biological processes, however, these approaches have also brought new challenges to determining genotype-phenotype correlations. In this chapter, we briefly review gene-editing technologies used in zebrafish and discuss the differences in phenotypes that can arise when gene expression is inhibited by anti-sense or by gene editing techniques. We outline possible explanations for why knockout phenotypes are milder, tissue-restricted, or even absent, compared with severe knockdown phenotypes. One proposed explanation is transcriptional adaptation, a form of genetic robustness that is induced by deleterious mutations but not gene knockdowns. Although much is unknown about what triggers this process, its relevance in shaping genome expression has been shown in multiple animal models. We recently explored if transcriptional adaptation could explain genotype-phenotype discrepancies seen between two zebrafish models of the centrosomal protein Cep290 deficiency. We compared cilia-related phenotypes in knockdown (anti-sense) and knockout (mutation) Cep290 models and showed that only cep290 gene mutation induces the upregulation of genes encoding the cilia-associated small GTPases Arl3, Arl13b, and Unc119b. Importantly, the ectopic expression of Arl3, Arl13b, and Unc119b in cep290 morphant zebrafish embryos rescued cilia defects. Here we provide protocols and experimental approaches that can be used to explore if transcriptional adaptation may be modulating gene expression in a zebrafish ciliary mutant model.
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Leong YC, Sowden JC. Modeling Retinitis Pigmentosa with Patient-Derived iPSCs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:555-563. [PMID: 37440086 DOI: 10.1007/978-3-031-27681-1_81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Retinitis pigmentosa (RP) causes blindness in 1 out of 3000-4000 individuals worldwide. Understanding the disease mechanism underlying the death of photoreceptors in RP patient is crucial for the discovery and development of therapies to prevent and stop the progression of retinal degeneration. Despite having provided valuable insight into RP pathology, several shortcomings of animal models warrant the need for a better modeling system. This review discusses the current use of patient-derived induced pluripotent stem cells (iPSCs) to model RP and its advantages over animal models. Further improvement to enhance the representativeness of iPSC RP models is also discussed.
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Affiliation(s)
- Yeh Chwan Leong
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, University College London and NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Jane C Sowden
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, University College London and NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.
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Chahine Karam F, Loi TH, Ma A, Nash BM, Grigg JR, Parekh D, Riley LG, Farnsworth E, Bennetts B, Gonzalez-Cordero A, Jamieson RV. Human iPSC-Derived Retinal Organoids and Retinal Pigment Epithelium for Novel Intronic RPGR Variant Assessment for Therapy Suitability. J Pers Med 2022; 12:jpm12030502. [PMID: 35330501 PMCID: PMC8951517 DOI: 10.3390/jpm12030502] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 02/04/2023] Open
Abstract
The RPGR gene encodes Retinitis Pigmentosa GTPase Regulator, a known interactor with ciliary proteins, which is involved in maintaining healthy photoreceptor cells. Variants in RPGR are the main contributor to X-linked rod-cone dystrophy (RCD), and RPGR gene therapy approaches are in clinical trials. Hence, elucidation of the pathogenicity of novel RPGR variants is important for a patient therapy opportunity. Here, we describe a novel intronic RPGR variant, c.1415 − 9A>G, in a patient with RCD, which was classified as a variant of uncertain significance according to current clinical diagnostic criteria. The variant lay several base pairs intronic to the canonical splice acceptor site, raising suspicion of an RPGR RNA splicing abnormality and consequent protein dysfunction. To investigate disease causation in an appropriate disease model, induced pluripotent stem cells were generated from patient fibroblasts and differentiated to retinal pigment epithelium (iPSC-RPE) and retinal organoids (iPSC-RO). Abnormal RNA splicing of RPGR was demonstrated in patient fibroblasts, iPSC-RPE and iPSC-ROs, leading to a predicted frameshift and premature stop codon. Decreased RPGR expression was demonstrated in these cell types, with a striking loss of RPGR localization at the ciliary transitional zone, critically in the photoreceptor cilium of the patient iPSC-ROs. Mislocalisation of rhodopsin staining was present in the patient’s iPSC-RO rod photoreceptor cells, along with an abnormality of L/M opsin staining affecting cone photoreceptor cells and increased photoreceptor apoptosis. Additionally, patient iPSC-ROs displayed an increase in F-actin expression that was consistent with an abnormal actin regulation phenotype. Collectively, these studies indicate that the splicing abnormality caused by the c.1415 − 9A>G variant has an impact on RPGR function. This work has enabled the reclassification of this variant to pathogenic, allowing the consideration of patients with this variant having access to gene therapy clinical trials. In addition, we have identified biomarkers of disease suitable for the interrogation of other RPGR variants of uncertain significance.
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Affiliation(s)
- Fidelle Chahine Karam
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
| | - To Ha Loi
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
| | - Alan Ma
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Department of Clinical Genetics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
| | - Benjamin M. Nash
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
| | - John R. Grigg
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Specialty of Ophthalmology, Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
| | - Darshan Parekh
- Rare Diseases Functional Genomics Laboratory, Sydney Children’s Hospitals Network and Children’s Medical Research Institute, Westmead, Sydney 2145, Australia; (D.P.); (L.G.R.)
| | - Lisa G. Riley
- Rare Diseases Functional Genomics Laboratory, Sydney Children’s Hospitals Network and Children’s Medical Research Institute, Westmead, Sydney 2145, Australia; (D.P.); (L.G.R.)
- Specialty of Child and Adolescent Health, University of Sydney, Westmead, Sydney 2145, Australia
| | - Elizabeth Farnsworth
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
| | - Bruce Bennetts
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
| | - Anai Gonzalez-Cordero
- Stem Cell Medicine Group, Children’s Medical Research Institute, University of Sydney, Westmead, Sydney 2145, Australia;
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
| | - Robyn V. Jamieson
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Department of Clinical Genetics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Correspondence: ; Tel.: +61-2-9687-2800; Fax: +61-2-9687-2120
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Sahu B, Leon LM, Zhang W, Puranik N, Periasamy R, Khanna H, Volkert M. Oxidative Stress Resistance 1 Gene Therapy Retards Neurodegeneration in the rd1 Mutant Mouse Model of Retinopathy. Invest Ophthalmol Vis Sci 2021; 62:8. [PMID: 34505865 PMCID: PMC8434758 DOI: 10.1167/iovs.62.12.8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/19/2021] [Indexed: 12/17/2022] Open
Abstract
Purpose Oxidative stress is a major factor underlying many neurodegenerative diseases. However, antioxidant therapy has had mixed results, possibly because of its indiscriminate activity. The purpose of our study was to determine if the human OXR1 (hOXR1) antioxidant regulatory gene could protect neurons from oxidative stress and delay photoreceptor cell death. Methods The cone-like 661W cell line was transfected to stably express the hOXR1 gene. Oxidative stress was induced by the addition of hydrogen peroxide (H2O2). Intracellular levels of reactive oxygen species (ROS), caspase cleavage, and cellular resistance to oxidative stress were determined and compared between the control and hOXR1 cells. For in vivo analysis, AAV8-hOXR1 was injected subretinally into the rd1 mouse model of retinal degeneration. Functional and structural integrity of the photoreceptors were assessed using electroretinography (ERG), histology, and immunofluorescence analysis. Results Expression of hOXR1 increased cellular resistance and reduced ROS levels and caspase cleavage in the 661W cell line after H2O2-induced oxidative stress. Subretinal injection of AAV8-hOXR1 in the rd1 mice improved their photoreceptor light response, expression and localization of photoreceptor-specific proteins, and delayed retinal degeneration. Conclusions Our results suggest that OXR1 is a potential therapy candidate for retinal degeneration. Because OXR1 targets oxidative stress, a common feature of many retinal degenerative diseases, it should be of therapeutic value to multiple retinal degenerative diseases.
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Affiliation(s)
- Bhubanananda Sahu
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Laura Moreno Leon
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Wei Zhang
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Nikita Puranik
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Ramesh Periasamy
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Hemant Khanna
- Department of Ophthalmology and Visual Science, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- NeuroNexus Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Michael Volkert
- NeuroNexus Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States
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8
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Cardenas-Rodriguez M, Austin-Tse C, Bergboer JGM, Molinari E, Sugano Y, Bachmann-Gagescu R, Sayer JA, Drummond IA. Genetic compensation for cilia defects in cep290 mutants by upregulation of cilia-associated small GTPases. J Cell Sci 2021; 134:jcs258568. [PMID: 34155518 PMCID: PMC8325957 DOI: 10.1242/jcs.258568] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/02/2021] [Indexed: 12/13/2022] Open
Abstract
Mutations in CEP290 (also known as NPHP6), a large multidomain coiled coil protein, are associated with multiple cilia-associated syndromes. Over 130 CEP290 mutations have been linked to a wide spectrum of human ciliopathies, raising the question of how mutations in a single gene cause different disease syndromes. In zebrafish, the expressivity of cep290 deficiencies were linked to the type of genetic ablation: acute cep290 morpholino knockdown caused severe cilia-related phenotypes, whereas deficiencies in a CRISPR/Cas9 genetic mutant were restricted to photoreceptor defects. Here, we show that milder phenotypes in genetic mutants were associated with the upregulation of genes encoding the cilia-associated small GTPases arl3, arl13b and unc119b. Upregulation of UNC119b was also observed in urine-derived renal epithelial cells from human Joubert syndrome CEP290 patients. Ectopic expression of arl3, arl13b and unc119b in cep290 morphant zebrafish embryos rescued Kupffer's vesicle cilia and partially rescued photoreceptor outer segment defects. The results suggest that genetic compensation by upregulation of genes involved in a common subcellular process, lipidated protein trafficking to cilia, may be a conserved mechanism contributing to genotype-phenotype variations observed in CEP290 deficiencies. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Magdalena Cardenas-Rodriguez
- Department of Medicine, Nephrology Division, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129, USA
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay
| | - Christina Austin-Tse
- Department of Pathology, Massachusetts General Hospital, 185 Cambridge St, Boston, MA 02114, USA
| | | | - Elisa Molinari
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle NE1 3BZ, UK
| | - Yuya Sugano
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | | | - John A. Sayer
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle NE1 3BZ, UK
- Renal Services, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Freeman Road, Newcastle NE7 7DN, UK
| | - Iain A. Drummond
- Department of Medicine, Nephrology Division, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129, USA
- Davis Center for Regenerative Biology and Aging, Mount Desert Island Biological Laboratory, Salisbury Cove, Bar Harbor, ME 04609, USA
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9
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Marquez J, Mann N, Arana K, Deniz E, Ji W, Konstantino M, Mis EK, Deshpande C, Jeffries L, McGlynn J, Hugo H, Widmeier E, Konrad M, Tasic V, Morotti R, Baptista J, Ellard S, Lakhani SA, Hildebrandt F, Khokha MK. DLG5 variants are associated with multiple congenital anomalies including ciliopathy phenotypes. J Med Genet 2021; 58:453-464. [PMID: 32631816 PMCID: PMC7785698 DOI: 10.1136/jmedgenet-2019-106805] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 05/01/2020] [Accepted: 05/25/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Cilia are dynamic cellular extensions that generate and sense signals to orchestrate proper development and tissue homeostasis. They rely on the underlying polarisation of cells to participate in signalling. Cilia dysfunction is a well-known cause of several diseases that affect multiple organ systems including the kidneys, brain, heart, respiratory tract, skeleton and retina. METHODS Among individuals from four unrelated families, we identified variants in discs large 5 (DLG5) that manifested in a variety of pathologies. In our proband, we also examined patient tissues. We depleted dlg5 in Xenopus tropicalis frog embryos to generate a loss-of-function model. Finally, we tested the pathogenicity of DLG5 patient variants through rescue experiments in the frog model. RESULTS Patients with variants of DLG5 were found to have a variety of phenotypes including cystic kidneys, nephrotic syndrome, hydrocephalus, limb abnormalities, congenital heart disease and craniofacial malformations. We also observed a loss of cilia in cystic kidney tissue of our proband. Knockdown of dlg5 in Xenopus embryos recapitulated many of these phenotypes and resulted in a loss of cilia in multiple tissues. Unlike introduction of wildtype DLG5 in frog embryos depleted of dlg5, introduction of DLG5 patient variants was largely ineffective in restoring proper ciliation and tissue morphology in the kidney and brain suggesting that the variants were indeed detrimental to function. CONCLUSION These findings in both patient tissues and Xenopus shed light on how mutations in DLG5 may lead to tissue-specific manifestations of disease. DLG5 is essential for cilia and many of the patient phenotypes are in the ciliopathy spectrum.
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Affiliation(s)
- Jonathan Marquez
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Nina Mann
- Division of Nephrology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Kathya Arana
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Engin Deniz
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Weizhen Ji
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Monica Konstantino
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Emily K Mis
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | - Lauren Jeffries
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Julie McGlynn
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Hannah Hugo
- Division of Nephrology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Eugen Widmeier
- Division of Nephrology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Martin Konrad
- Department of General Pediatrics, University Hospital Münster, Münster, Germany
| | - Velibor Tasic
- Department of Pediatric Nephrology, University Children's Hospital, Skopje, North Macedonia
| | - Raffaella Morotti
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Julia Baptista
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
- Institute of Biomedical & Clinical Science, College of Medicine and Health, Exeter, UK
| | - Sian Ellard
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
- Institute of Biomedical & Clinical Science, College of Medicine and Health, Exeter, UK
| | - Saquib Ali Lakhani
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Friedhelm Hildebrandt
- Division of Nephrology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Mustafa K Khokha
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
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10
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Birtel J, Spital G, Book M, Habbig S, Bäumner S, Riehmer V, Beck BB, Rosenkranz D, Bolz HJ, Dahmer-Heath M, Herrmann P, König J, Charbel Issa P. NPHP1 gene-associated nephronophthisis is associated with an occult retinopathy. Kidney Int 2021; 100:1092-1100. [PMID: 34153329 DOI: 10.1016/j.kint.2021.06.012] [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: 01/21/2021] [Revised: 05/04/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Biallelic deletions in the NPHP1 gene are the most frequent molecular defect of nephronophthisis, a kidney ciliopathy and leading cause of hereditary end-stage kidney disease. Nephrocystin 1, the gene product of NPHP1, is also expressed in photoreceptors where it plays an important role in intra-flagellar transport between the inner and outer segments. However, the human retinal phenotype has never been investigated in detail. Here, we characterized retinal features of 16 patients with homozygous deletions of the entire NPHP1 gene. Retinal assessment included multimodal imaging (optical coherence tomography, fundus autofluorescence) and visual function testing (visual acuity, full-field electroretinography, color vision, visual field). Fifteen patients had a mild retinal phenotype that predominantly affected cones, but with relative sparing of the fovea. Despite a predominant cone dysfunction, night vision problems were an early symptom in some cases. The consistent retinal phenotype on optical coherence tomography images included reduced reflectivity and often a granular appearance of the ellipsoid zone, fading or loss of the interdigitation zone, and mild outer retinal thinning. However, there were usually no obvious structural changes visible upon clinical examination and fundus autofluorescence imaging (occult retinopathy). More advanced retinal degeneration might occur with ageing. An identified additional CEP290 variant in one patient with a more severe retinal degeneration may indicate a potential role for genetic modifiers, although this requires further investigation. Thus, diagnostic awareness about this distinct retinal phenotype has implications for the differential diagnosis of nephronophthisis and for individual prognosis of visual function.
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Affiliation(s)
- Johannes Birtel
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Georg Spital
- Eye Center at St. Franziskus-Hospital Münster, Münster, Germany
| | - Marius Book
- Eye Center at St. Franziskus-Hospital Münster, Münster, Germany
| | - Sandra Habbig
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Sören Bäumner
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Vera Riehmer
- Institute of Human Genetics, University of Cologne, University Hospital of Cologne, Cologne, Germany
| | - Bodo B Beck
- Institute of Human Genetics, University of Cologne, University Hospital of Cologne, Cologne, Germany; Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases Cologne, University of Cologne, University Hospital of Cologne, Cologne, Germany
| | | | - Hanno J Bolz
- Institute of Human Genetics, University of Cologne, University Hospital of Cologne, Cologne, Germany; Senckenberg Centre for Human Genetics, Frankfurt, Germany
| | - Mareike Dahmer-Heath
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | | | - Jens König
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Peter Charbel Issa
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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11
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Datta P, Cribbs JT, Seo S. Differential requirement of NPHP1 for compartmentalized protein localization during photoreceptor outer segment development and maintenance. PLoS One 2021; 16:e0246358. [PMID: 33961633 PMCID: PMC8104407 DOI: 10.1371/journal.pone.0246358] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
Nephrocystin (NPHP1) is a ciliary transition zone protein and its ablation causes nephronophthisis (NPHP) with partially penetrant retinal dystrophy. However, the precise requirements of NPHP1 in photoreceptors are not well understood. Here, we characterize retinal degeneration in a mouse model of NPHP1 and show that NPHP1 is required to prevent infiltration of inner segment plasma membrane proteins into the outer segment during the photoreceptor maturation. We demonstrate that Nphp1 gene-trap mutant mice, which were previously described as null, are likely hypomorphs due to the production of a small quantity of functional mRNAs derived from nonsense-associated altered splicing and skipping of two exons including the one harboring the gene-trap. In homozygous mutant animals, inner segment plasma membrane proteins such as syntaxin-3 (STX3), synaptosomal-associated protein 25 (SNAP25), and interphotoreceptor matrix proteoglycan 2 (IMPG2) accumulate in the outer segment when outer segments are actively elongating. This phenotype, however, is spontaneously ameliorated after the outer segment elongation is completed. Consistent with this, some photoreceptor cell loss (~30%) occurs during the photoreceptor maturation period but it stops afterward. We further show that Nphp1 genetically interacts with Cep290, another NPHP gene, and that a reduction of Cep290 gene dose results in retinal degeneration that continues until adulthood in Nphp1 mutant mice. These findings demonstrate that NPHP1 is required for the confinement of inner segment plasma membrane proteins during the outer segment development, but its requirement diminishes as photoreceptors mature. Our study also suggests that additional mutations in other NPHP genes may influence the penetrance of retinopathy in human NPHP1 patients.
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Affiliation(s)
- Poppy Datta
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
| | - J. Thomas Cribbs
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
- * E-mail:
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12
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Vilaplana F, Ros A, Garcia B, Blanco I, Castellanos E, Edwards NJ, Valldeperas X, Ruiz-Bilbao S, Sabala A. Clinical characteristics, imaging findings, and genetic results of a patient with CEP290-related cone-rod dystrophy. Ophthalmic Genet 2021; 42:474-479. [PMID: 33886416 DOI: 10.1080/13816810.2021.1916827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE To describe the clinical characteristics, the imaging findings, and the genetic results of a patient with cone-rod dystrophy (CORD) related to mutations in CEP290. METHODS A case report of atypical CEP290-related CORD. Ophthalmological examination was performed, including best-corrected visual acuity (BCVA), fundus photography, fundus autofluorescence (FAF) imaging, optical coherence tomography (OCT), a visual field test, and electroretinography testing. The genetic test was performed by next-generation sequencing (NGS)-based panel test containing 336 genes. RESULTS A 57-year-old female who had reported a visual loss for 5 years. BCVA was 20/100 in both eyes. The fundus examination revealed a hypopigmented halo around the fovea, showing a paracentral hyperautofluorescent ring on FAF. OCT demonstrated the presence of atrophy in the outer retinal layers. The genetic test identified the probably pathogenic variants c.4028delA and c.5254C>T in compound heterozygosis in CEP290. CONCLUSIONS This is the first report to present the clinical characteristics, imaging findings, and genetic test results of a patient with CEP290-related CORD. Our case contributes to expanding the clinical involvement of CEP290 pathogenic variants. This study indicates that CEP290-related CORD may have a mild phenotype with late-onset dystrophy, making these patients interesting candidates for innovative treatments such as genetic therapeutic approaches.
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Affiliation(s)
- Ferran Vilaplana
- Department of Ophthalmology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Andrea Ros
- Genetic Counseling Unit, Genetics Service, Hospital Universitari Germans Trias i Pujol, Barcelona, Spain
| | - Belen Garcia
- Genetic Counseling Unit, Genetics Service, Hospital Universitari Germans Trias i Pujol, Barcelona, Spain
| | - Ignacio Blanco
- Genetic Counseling Unit, Genetics Service, Hospital Universitari Germans Trias i Pujol, Barcelona, Spain
| | - Elisabeth Castellanos
- Clinical Genomics Unit, Genetics Service, Hospital Universitari Germans Trias i Pujol, Barcelona, Spain.,Hereditary Cancer Group, Germans Trias Research Institute, IGTP, Barcelona, Spain
| | | | - Xavier Valldeperas
- Department of Ophthalmology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Susana Ruiz-Bilbao
- Department of Ophthalmology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Antonio Sabala
- Department of Ophthalmology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Barcelona, Spain
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13
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Hadalin V, Šuštar M, Volk M, Maver A, Sajovic J, Jarc-Vidmar M, Peterlin B, Hawlina M, Fakin A. Cone Dystrophy Associated with a Novel Variant in the Terminal Codon of the RPGR- ORF15. Genes (Basel) 2021; 12:genes12040499. [PMID: 33805381 PMCID: PMC8066792 DOI: 10.3390/genes12040499] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/30/2022] Open
Abstract
Mutations in RPGRORF15 are associated with rod-cone or cone/cone-rod dystrophy, the latter associated with mutations at the distal end. We describe the phenotype associated with a novel variant in the terminal codon of the RPGRORF15 c.3457T>A (Ter1153Lysext*38), which results in a C-terminal extension. Three male patients from two families were recruited, aged 31, 35, and 38 years. Genetic testing was performed by whole exome sequencing. Filtered variants were analysed according to the population frequency, ClinVar database, the variant’s putative impact, and predicted pathogenicity; and were classified according to the ACMG guidelines. Examination included visual acuity (Snellen), colour vision (Ishihara), visual field, fundus autofluorescence (FAF), optical coherence tomography (OCT), and electrophysiology. All patients were myopic, and had central scotoma and reduced colour vision. Visual acuities on better eyes were counting fingers, 0.3 and 0.05. Electrophysiology showed severely reduced cone-specific responses and macular dysfunction, while the rod-specific response was normal. FAF showed hyperautofluorescent ring centred at the fovea encompassing an area of photoreceptor loss approximately two optic discs in diameter (3462–6342 μm). Follow up after 2–11 years showed enlargement of the diameter (avg. 100 μm/year). The novel c.3457T>A (Ter1153Lysext*38) mutation in the terminal RPGRORF15 codon is associated with cone dystrophy, which corresponds to the previously described phenotypes associated with mutations in the distal end of the RPGRORF15. Minimal progression during follow-up years suggests a relatively stable disease after the initial loss of the central cones.
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Affiliation(s)
- Vlasta Hadalin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Maja Šuštar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Marija Volk
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Aleš Maver
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Jana Sajovic
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Martina Jarc-Vidmar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Borut Peterlin
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
- Correspondence:
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14
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Role of DZIP1-CBY-FAM92 transition zone complex in the basal body to membrane attachment and ciliary budding. Biochem Soc Trans 2021; 48:1067-1075. [PMID: 32491167 DOI: 10.1042/bst20191007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/20/2020] [Accepted: 05/07/2020] [Indexed: 02/07/2023]
Abstract
Cilia play important signaling or motile functions in various organisms. In Human, cilia dysfunctions are responsible for a wide range of diseases, called ciliopathies. Cilia assembly is a tightly controlled process, which starts with the conversion of the centriole into a basal body, leading to the formation of the ciliary bud that protrudes inside a ciliary vesicle and/or ultimately at the cell surface. Ciliary bud formation is associated with the assembly of the transition zone (TZ), a complex architecture of proteins of the ciliary base which plays critical functions in gating proteins in and out of the ciliary compartment. Many proteins are involved in the assembly of the TZ, which shows structural and functional variations in different cell types or organisms. In this review, we discuss how a particular complex, composed of members of the DZIP1, CBY and FAM92 families of proteins, is required for the initial stages of cilia assembly leading to ciliary bud formation and how their functional hierarchy contributes to TZ assembly. Moreover, we summarize how evidences in Drosophila reveal functional differences of the DZIP1-CBY-FAM92 complex in the different ciliated tissues of this organism. Whereas it is essential for proper TZ assembly in the two types of ciliated tissues, it is involved in stable anchoring of basal bodies to the plasma membrane in male germ cells. Overall, the DZIP1-CBY-FAM92 complex reveals a molecular assembly pathway required for the initial stages of ciliary bud formation and that is conserved from Drosophila to Human.
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15
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Moreno-Leon L, West EL, O’Hara-Wright M, Li L, Nair R, He J, Anand M, Sahu B, Chavali VRM, Smith AJ, Ali RR, Jacobson SG, Cideciyan AV, Khanna H. RPGR isoform imbalance causes ciliary defects due to exon ORF15 mutations in X-linked retinitis pigmentosa (XLRP). Hum Mol Genet 2021; 29:3706-3716. [PMID: 33355362 PMCID: PMC7823108 DOI: 10.1093/hmg/ddaa269] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 12/28/2022] Open
Abstract
Mutations in retinitis pigmentosa GTPase regulator (RPGR) cause severe retinal ciliopathy, X-linked retinitis pigmentosa. Although two major alternatively spliced isoforms, RPGRex1-19 and RPGRORF15, are expressed, the relative importance of these isoforms in disease pathogenesis is unclear. Here, we analyzed fibroblast samples from eight patients and found that all of them form longer cilia than normal controls, albeit to different degrees. Although all mutant RPGRORF15 messenger RNAs (mRNAs) are unstable, their steady-state levels were similar or higher than those in the control cells, suggesting there may be increased transcription. Three of the fibroblasts that had higher levels of mutant RPGRORF15 mRNA also exhibited significantly higher levels of RPGRex1-19 mRNA. Four samples with unaltered RPGRex1-19 levels carried mutations in RPGRORF15 that resulted in this isoform being relatively less stable. Thus, in all cases, the RPGRex1-19/RPGRORF15 isoform ratio was increased, and this was highly correlative to the cilia extension defect. Moreover, overexpression of RPGRex1-19 (mimicking the increase in RPGRex1-19 to RPGRORF15 isoform ratio) or RPGRORF15 (mimicking reduction of the ratio) resulted in significantly longer or shorter cilia, respectively. Notably, the cilia length defect appears to be attributable to both the loss of the wild-type RPGRORF15 protein and to the higher levels of the RPGRex1-19 isoform, indicating that the observed defect is due to the altered isoform ratios. These results suggest that maintaining the optimal RPGRex1-9 to RPGRORF15 ratio is critical for cilia growth and that designing strategies that focus on the best ways to restore the RPGRex1-19/RPGRORF15 ratio may lead to better therapeutic outcomes.
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Affiliation(s)
- Laura Moreno-Leon
- Department of Ophthalmology & Visual Sciences, UMass Medical School, Worcester, MA 01655, USA
| | - Emma L West
- Division of Molecular Therapy, UCL Institute of Ophthalmology, London EC1V 9El, UK
| | | | - Linjing Li
- Department of Ophthalmology & Visual Sciences, UMass Medical School, Worcester, MA 01655, USA
| | - Rohini Nair
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jie He
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Manisha Anand
- Department of Ophthalmology & Visual Sciences, UMass Medical School, Worcester, MA 01655, USA
| | - Bhubanananda Sahu
- Department of Ophthalmology & Visual Sciences, UMass Medical School, Worcester, MA 01655, USA
| | | | - Alexander J Smith
- Division of Molecular Therapy, UCL Institute of Ophthalmology, London EC1V 9El, UK
| | - Robin R Ali
- Division of Molecular Therapy, UCL Institute of Ophthalmology, London EC1V 9El, UK
| | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hemant Khanna
- Department of Ophthalmology & Visual Sciences, UMass Medical School, Worcester, MA 01655, USA
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16
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Chen HY, Kelley RA, Li T, Swaroop A. Primary cilia biogenesis and associated retinal ciliopathies. Semin Cell Dev Biol 2020; 110:70-88. [PMID: 32747192 PMCID: PMC7855621 DOI: 10.1016/j.semcdb.2020.07.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 12/19/2022]
Abstract
The primary cilium is a ubiquitous microtubule-based organelle that senses external environment and modulates diverse signaling pathways in different cell types and tissues. The cilium originates from the mother centriole through a complex set of cellular events requiring hundreds of distinct components. Aberrant ciliogenesis or ciliary transport leads to a broad spectrum of clinical entities with overlapping yet highly variable phenotypes, collectively called ciliopathies, which include sensory defects and syndromic disorders with multi-organ pathologies. For efficient light detection, photoreceptors in the retina elaborate a modified cilium known as the outer segment, which is packed with membranous discs enriched for components of the phototransduction machinery. Retinopathy phenotype involves dysfunction and/or degeneration of the light sensing photoreceptors and is highly penetrant in ciliopathies. This review will discuss primary cilia biogenesis and ciliopathies, with a focus on the retina, and the role of CP110-CEP290-CC2D2A network. We will also explore how recent technologies can advance our understanding of cilia biology and discuss new paradigms for developing potential therapies of retinal ciliopathies.
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Affiliation(s)
- Holly Y Chen
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
| | - Ryan A Kelley
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Tiansen Li
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
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17
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McKenzie CW, Lee L. Genetic interaction between central pair apparatus genes CFAP221, CFAP54, and SPEF2 in mouse models of primary ciliary dyskinesia. Sci Rep 2020; 10:12337. [PMID: 32704025 PMCID: PMC7378221 DOI: 10.1038/s41598-020-69359-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/06/2020] [Indexed: 12/21/2022] Open
Abstract
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous syndrome that results from defects in motile cilia. The ciliary axoneme has a 9 + 2 microtubule structure consisting of nine peripheral doublets surrounding a central pair apparatus (CPA), which plays a critical role in regulating proper ciliary function. We have previously shown that mouse models with mutations in CPA genes CFAP221, CFAP54, and SPEF2 have a PCD phenotype with defects in ciliary motility. In this study, we investigated potential genetic interaction between these CPA genes by generating each combination of double heterozygous and double homozygous mutants. No detectable cilia-related phenotypes were observed in double heterozygotes, but all three double homozygous mutant lines exhibit early mortality and typically develop severe PCD-associated phenotypes of hydrocephalus, mucociliary clearance defects in the upper airway, and abnormal spermatogenesis. Double homozygous cilia are generally intact and display a normal morphology and distribution. Spermiogenesis is aborted in double homozygotes, with an absence of mature flagella on elongating spermatids and epididymal sperm. These findings identify genetic interactions between CPA genes and genetic mechanisms regulating the CPA and motile cilia function.
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Affiliation(s)
- Casey W McKenzie
- Pediatrics and Rare Diseases Group, Sanford Research, 2301 E. 60th Street N., Sioux Falls, SD, 57104, USA
| | - Lance Lee
- Pediatrics and Rare Diseases Group, Sanford Research, 2301 E. 60th Street N., Sioux Falls, SD, 57104, USA. .,Department of Pediatrics, Sanford School of Medicine of the University of South Dakota, 1400 W. 22nd Street, Sioux Falls, SD, 57105, USA.
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18
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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19
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Joe MK, Li W, Hiriyanna S, Yu W, Shah SA, Abu-Asab M, Qian H, Wu Z. A Common Outer Retinal Change in Retinal Degeneration by Optical Coherence Tomography Can Be Used to Assess Outcomes of Gene Therapy. Hum Gene Ther 2019; 30:1520-1530. [PMID: 31672061 DOI: 10.1089/hum.2019.162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Identifying early disease hallmarks in animal models with slow disease progression may expedite disease detection and assessment of treatment outcomes. Using optical coherence tomography, a widely applied noninvasive method for monitoring retinal structure changes, we analyzed retinal optical sections from six mouse lines with retinal degeneration caused by mutations in different disease-causing genes. While images from wild-type mice revealed four well-separated hyper-reflective bands in the outer retina (designated as outer retina reflective bands, ORRBs) at all ages, the second band (ORRB2) and the third band (ORRB3) were merged in retinas of five mutant mouse lines at early ages, suggesting the pathological nature of this alteration. This ORRB change appeared to be degenerating photoreceptor related, and occurred before obvious morphological changes that can be identified on both hematoxylin and eosin-stained sections and electron microscopic sections. Importantly, the merging of ORRB2 and ORRB3 was reversed by treatment with adeno-associated viral vector-mediated gene replacement therapies, and this restoration occurred much earlier than measurable functional or structural improvement. Our data suggest that the ORRB change could be a common hallmark of early retinal degeneration and its restoration could be used for rapid and noninvasive assessment of therapeutic effects following gene therapy or other treatment interventions.
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Affiliation(s)
- Myung Kuk Joe
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wenbo Li
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Suja Hiriyanna
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wenhan Yu
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Shreya A Shah
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Mones Abu-Asab
- Histopathology Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Zhijian Wu
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
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20
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Barny I, Perrault I, Michel C, Soussan M, Goudin N, Rio M, Thomas S, Attié-Bitach T, Hamel C, Dollfus H, Kaplan J, Rozet JM, Gerard X. Basal exon skipping and nonsense-associated altered splicing allows bypassing complete CEP290 loss-of-function in individuals with unusually mild retinal disease. Hum Mol Genet 2019; 27:2689-2702. [PMID: 29771326 DOI: 10.1093/hmg/ddy179] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/02/2018] [Accepted: 05/06/2018] [Indexed: 12/18/2022] Open
Abstract
CEP290 mutations cause a spectrum of ciliopathies from Leber congenital amaurosis type 10 (LCA10) to embryo-lethal Meckel syndrome (MKS). Using panel-based molecular diagnosis testing for inherited retinal diseases, we identified two individuals with some preserved vision despite biallelism for presumably truncating CEP290 mutations. The first one carried a homozygous 1 base pair deletion in Exon 17, introducing a premature termination codon (PTC) in Exon 18 (c.1666del; p.Ile556Phefs*17). mRNA analysis revealed a basal exon skipping (BES) of Exon 18, providing mutant cells with the ability to escape protein truncation, while disrupting the reading frame in controls. The second individual harbored compound heterozygous nonsense mutations in Exon 8 (c.508A>T, p.Lys170*) and Exon 32 (c.4090G>T, p.Glu1364*), respectively. Some CEP290 lacking Exon 8 were detected in mutant fibroblasts but not in controls whereas some skipping of Exon 32 occurred in both lines, but with higher amplitude in the mutant. Considering that the deletion of either exon maintains the reading frame in either line, skipping in mutant cells likely involves nonsense-associated altered splicing alone (Exon 8), or with BES (Exon 32). Skipping of PTC-containing exons in mutant cells allowed production of CEP290 isoforms with preserved ability to assemble into a high molecular weight complex and to interact efficiently with proteins important for cilia formation and intraflagellar trafficking. In contrast, studying LCA10 and MKS fibroblasts we show moderate to severe cilia alterations, providing support for a correlation between disease severity and the ability of cells to express shortened, yet functional, CEP290 isoforms.
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Affiliation(s)
- Iris Barny
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases
| | - Christel Michel
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases
| | - Mickael Soussan
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases
| | - Nicolas Goudin
- Cell Imaging Core Facility of the Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Imagine and Paris Descartes University, Paris, France
| | - Marlène Rio
- Department of Genetics, IHU Necker-Enfants Malades, University Paris Descartes, Paris, France
| | - Sophie Thomas
- Laboratory of Embryology and Genetics of Human Malformation, INSERM UMR1163, Institute of Genetics Diseases, Imagine and Paris Descartes University, Paris, France
| | - Tania Attié-Bitach
- Laboratory of Embryology and Genetics of Human Malformation, INSERM UMR1163, Institute of Genetics Diseases, Imagine and Paris Descartes University, Paris, France
| | - Christian Hamel
- Centre de Référence des Affections Sensorielles Génétiques, Institut des Neurosciences de Montpellier, CHU-Saint Eloi Montpellier, Montpellier, France
| | - Hélène Dollfus
- Centre de Référence pour les Affections Génétiques Ophtalmologiques CARGO, CHRU Strasbourg, INSERM 1112, Université de Strasbourg, Strasbourg, France
| | - Josseline Kaplan
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases
| | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases
| | - Xavier Gerard
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases
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21
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Fahim AT, Sullivan LS, Bowne SJ, Jones KD, Wheaton DKH, Khan NW, Heckenlively JR, Jayasundera KT, Branham KH, Andrews CA, Othman MI, Karoukis AJ, Birch DG, Daiger SP. X-Chromosome Inactivation Is a Biomarker of Clinical Severity in Female Carriers of RPGR-Associated X-Linked Retinitis Pigmentosa. Ophthalmol Retina 2019; 4:510-520. [PMID: 31953110 DOI: 10.1016/j.oret.2019.11.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 11/16/2022]
Abstract
PURPOSE X-linked retinitis pigmentosa can manifest in female carriers with widely variable severity, whereas others remain unaffected. The contribution of X-chromosome inactivation (XCI) to phenotypic variation has been postulated but not demonstrated. Furthermore, the impact of genotype and genetic modifiers has been demonstrated in affected males but has not been well established in female carriers. The purpose of this study was to describe the scope of clinical phenotype in female carriers with mutations in RPGR and quantify the contribution of genotype, genetic modifiers, and XCI to phenotypic severity. DESIGN Cohort study. PARTICIPANTS Seventy-seven female carriers with RPGR mutations from 41 pedigrees. METHODS Coding single nucleotide polymorphisms were sequenced in candidate genetic modifier genes encoding known RPGR-interacting proteins. X-chromosome inactivation ratios were determined in genomic DNA isolated from blood (n = 42) and saliva (n = 20) using methylation status of X-linked polymorphic repeats. These genetic data were compared with disease severity based on quantitative clinical parameters. MAIN OUTCOME MEASURES Visual acuity, Humphrey visual field (HVF) results, full-field electroretinography results, and dark adaptation. RESULTS Most individuals at all ages were mildly affected or unaffected, whereas those who progressed to moderate or severe vision loss were older than 30 years. RPGR genotype was not associated with clinical severity. The D1264N variant in RPGRIP1L was associated with more severe disease. Skewed XCI toward inactivation of the normal RPGR allele was associated with more severe disease. The XCI ratio in both blood and saliva was a predictor of visual function as measured by HVF diameter, rod amplitude, flicker amplitude, and flicker implicit time. For carriers with extreme XCI skewing of 80:20 or more, 57% were affected severely compared with 8% for those with XCI of less than 80:20 (P = 0.002). CONCLUSIONS Female carriers with mutations in RPGR demonstrate widely variable clinical severity. X-chromosome inactivation ratios correlate with clinical severity and may serve as a predictor of clinically significant disease. Because RPGR gene therapy trials are underway, a future imperative exists to determine which carriers require intervention and when to intervene. X-chromosome inactivation analysis may be useful for identifying candidates for early intervention.
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Affiliation(s)
- Abigail T Fahim
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan.
| | - Lori S Sullivan
- Department of Genetics, University of Texas Health Science Center, Houston, Texas
| | - Sara J Bowne
- Department of Genetics, University of Texas Health Science Center, Houston, Texas
| | | | | | - Naheed W Khan
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - John R Heckenlively
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - K Thiran Jayasundera
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Kari H Branham
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Chris A Andrews
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Mohammad I Othman
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Athanasios J Karoukis
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | | | - Stephen P Daiger
- Department of Genetics, University of Texas Health Science Center, Houston, Texas
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22
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Shivanna M, Anand M, Chakrabarti S, Khanna H. Ocular Ciliopathies: Genetic and Mechanistic Insights into Developing Therapies. Curr Med Chem 2019; 26:3120-3131. [PMID: 30221600 DOI: 10.2174/0929867325666180917102557] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/21/2018] [Accepted: 09/05/2018] [Indexed: 12/12/2022]
Abstract
Developing suitable medicines for genetic diseases requires a detailed understanding of not only the pathways that cause the disease, but also the identification of the genetic components involved in disease manifestation. This article focuses on the complexities associated with ocular ciliopathies - a class of debilitating disorders of the eye caused by ciliary dysfunction. Ciliated cell types have been identified in both the anterior and posterior segments of the eye. Photoreceptors (rods and cones) are the most studied ciliated neurons in the retina, which is located in the posterior eye. The photoreceptors contain a specialized lightsensing outer segment, or cilium. Any defects in the development or maintenance of the outer segment can result in severe retinal ciliopathies, such as retinitis pigmentosa and Leber congenital amaurosis. A role of cilia in the cell types involved in regulating aqueous fluid outflow in the anterior segment of the eye has also been recognized. Defects in these cell types are frequently associated with some forms of glaucoma. Here, we will discuss the significance of understanding the genetic heterogeneity and the pathogenesis of ocular ciliopathies to develop suitable treatment strategies for these blinding disorders.
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Affiliation(s)
- Mahesh Shivanna
- School of Optometry, Massachusetts College of Pharmacy and Health Sciences University, Worcester, MA, United States
| | - Manisha Anand
- UMASS Medical School, Worcester, MA 01605, United States
| | | | - Hemant Khanna
- UMASS Medical School, Worcester, MA 01605, United States
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23
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Khanna H. More Than Meets the Eye: Current Understanding of RPGR Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1074:521-538. [PMID: 29721984 DOI: 10.1007/978-3-319-75402-4_64] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
This article summarizes the recent advances in our understanding of a major retinal disease gene RPGR (retinitis pigmentosa GTPase regulator), mutations in which are associated with majority of X-linked forms of retinal degenerations. A great deal of work has been done to uncover the ciliary localization of RPGR and its interacting proteins in the retina. However, the molecular mechanisms of action of RPGR in the photoreceptors are still unclear. Recent studies have begun to shed light on the intracellular pathways in which RPGR is likely involved. The deregulation of such pathways may underlie the pathogenesis of severe retinal degeneration associated with RPGR. With the recent advances in the gene augmentation therapy for RPGR-associated disease, there is a lot of excitement in the field. Patients with RPGR mutations, however, present with clinically heterogeneous manifestations. It is therefore imperative to examine the function of RPGR in detail, so that we can design patient-oriented therapeutic strategies for this disease.
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Affiliation(s)
- Hemant Khanna
- Department of Ophthalmology and Neurobiology, UMASS Medical School, Worcester, MA, USA.
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24
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Barny I, Perrault I, Rio M, Dollfus H, Defoort-Dhellemmes S, Kaplan J, Rozet JM, Gerard X. Description of Two Siblings with Apparently Severe CEP290 Mutations and Unusually Mild Retinal Disease Unrelated to Basal Exon Skipping or Nonsense-Associated Altered Splicing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:189-195. [PMID: 31884610 DOI: 10.1007/978-3-030-27378-1_31] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CEP290 mutations cause a spectrum of ciliopathies, including Leber congenital amaurosis. Milder retinal diseases have been ascribed to exclusion of CEP290 mutant exons through basal exon skipping (BES) and/or nonsense-associated altered splicing (NAS). Here, we report two siblings with some preserved vision despite biallelism for presumably severe CEP290 mutations: a maternal splice site change in intron 18 (c.1824 + 3A > G) and a paternal c.6869dup (p.Asn2290Lysfs∗6) in exon 50 that introduces a premature termination codon (PTC) within the same exon. Analyzing mRNAs from fibroblasts of the two siblings, we detected no BES or NAS which could have enabled the production of PTC-free CEP290 isoforms from the paternal allele. In contrast, we reveal partial alteration of exon 18 donor splice site, allowing the transcription of some correctly spliced CEP290 mRNAs from the maternal allele which likely account for the mild retinal disease. This observation adds further variability to the mechanisms underlying CEP290 pleiotropy.
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Affiliation(s)
- Iris Barny
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases, Imagine and Paris Descartes University, Paris, France
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases, Imagine and Paris Descartes University, Paris, France
| | - Marlène Rio
- Department of Genetics, IHU Necker-Enfants Malades, University Paris Descartes, Paris, France
| | - Hélène Dollfus
- Centre des Affections Rares en Génétique Ophtalmologique CARGO, CHRU Strasbourg, INSERM1112, Université de Strasbourg, Strasbourg, France
| | - Sabine Defoort-Dhellemmes
- Service d'exploration de la Vision et Neuro-ophtalmologie, Pôle d'Imagerie et Explorations Fonctionnelles, CHRU de Lille, Lille, France
| | - Josseline Kaplan
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases, Imagine and Paris Descartes University, Paris, France
| | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases, Imagine and Paris Descartes University, Paris, France.
| | - Xavier Gerard
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetics Diseases, Imagine and Paris Descartes University, Paris, France. .,Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University of Lausanne, Hôpital Ophtalmique Jules Gonin, Lausanne, Switzerland.
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25
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Dharmat R, Eblimit A, Robichaux MA, Zhang Z, Nguyen TMT, Jung SY, He F, Jain A, Li Y, Qin J, Overbeek P, Roepman R, Mardon G, Wensel TG, Chen R. SPATA7 maintains a novel photoreceptor-specific zone in the distal connecting cilium. J Cell Biol 2018; 217:2851-2865. [PMID: 29899041 PMCID: PMC6080925 DOI: 10.1083/jcb.201712117] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/09/2018] [Accepted: 05/23/2018] [Indexed: 12/25/2022] Open
Abstract
Photoreceptor-specific ciliopathies often affect a structure that is considered functionally homologous to the ciliary transition zone (TZ) called the connecting cilium (CC). However, it is unclear how mutations in certain ciliary genes disrupt the photoreceptor CC without impacting the primary cilia systemically. By applying stochastic optical reconstruction microscopy technology in different genetic models, we show that the CC can be partitioned into two regions: the proximal CC (PCC), which is homologous to the TZ of primary cilia, and the distal CC (DCC), a photoreceptor-specific extension of the ciliary TZ. This specialized distal zone of the CC in photoreceptors is maintained by SPATA7, which interacts with other photoreceptor-specific ciliary proteins such as RPGR and RPGRIP1. The absence of Spata7 results in the mislocalization of DCC proteins without affecting the PCC protein complexes. This collapse results in destabilization of the axonemal microtubules, which consequently results in photoreceptor degeneration. These data provide a novel mechanism to explain how genetic disruption of ubiquitously present ciliary proteins exerts tissue-specific ciliopathy phenotypes.
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Affiliation(s)
- Rachayata Dharmat
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Aiden Eblimit
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Michael A Robichaux
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Zhixian Zhang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Thanh-Minh T Nguyen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Sung Yun Jung
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Antrix Jain
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Yumei Li
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Jun Qin
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Paul Overbeek
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Ronald Roepman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Graeme Mardon
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
- Pathology and Immunology, Baylor College of Medicine, Houston, TX
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
| | - Rui Chen
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX
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26
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Moye AR, Singh R, Kimler VA, Dilan TL, Munezero D, Saravanan T, Goldberg AFX, Ramamurthy V. ARL2BP, a protein linked to retinitis pigmentosa, is needed for normal photoreceptor cilia doublets and outer segment structure. Mol Biol Cell 2018; 29:1590-1598. [PMID: 29718757 PMCID: PMC6080659 DOI: 10.1091/mbc.e18-01-0040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The outer segment (OS) of photoreceptor cells is an elaboration of a primary cilium with organized stacks of membranous disks that contain the proteins needed for phototransduction and vision. Though ciliary formation and function has been well characterized, little is known about the role of cilia in the development of photoreceptor OS. Nevertheless, progress has been made by studying mutations in ciliary proteins, which often result in malformed OSs and lead to blinding diseases. To investigate how ciliary proteins contribute to OS formation, we generated a knockout (KO) mouse model for ARL2BP, a ciliary protein linked to retinitis pigmentosa. The KO mice display an early and progressive reduction in visual response. Before photoreceptor degeneration, we observed disorganization of the photoreceptor OS, with vertically aligned disks and shortened axonemes. Interestingly, ciliary doublet microtubule (MT) structure was also impaired, displaying open B-tubule doublets, paired with loss of singlet MTs. On the basis of results from this study, we conclude that ARL2BP is necessary for photoreceptor ciliary doublet formation and axoneme elongation, which is required for OS morphogenesis and vision.
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Affiliation(s)
- Abigail R Moye
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506.,Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Ratnesh Singh
- Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | | | - Tanya L Dilan
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506.,Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Daniella Munezero
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506.,Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | | | | | - Visvanathan Ramamurthy
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506.,Department of Biochemistry, West Virginia University, Morgantown, WV 26506.,Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV 26506
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27
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Zhang W, Li L, Su Q, Gao G, Khanna H. Gene Therapy Using a miniCEP290 Fragment Delays Photoreceptor Degeneration in a Mouse Model of Leber Congenital Amaurosis. Hum Gene Ther 2018; 29:42-50. [PMID: 28679290 PMCID: PMC5770090 DOI: 10.1089/hum.2017.049] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/27/2017] [Indexed: 12/25/2022] Open
Abstract
Mutations in the cilia-centrosomal protein CEP290 are frequently observed in autosomal recessive childhood blindness disorder Leber congenital amaurosis (LCA). No treatment or cure currently exists for this disorder. The Cep290rd16 (retinal degeneration 16) mouse (a model of LCA) carries a mutation in the Cep290 gene. This mutation leads to shorter cilia formation and defective photoreceptor structure and function. A roadblock to developing a gene replacement strategy for CEP290 using conventional adeno-associated virus (AAV) vectors is its large size. The identification and characterization is reported of a miniCEP290 gene that is amenable to AAV2/8-mediated delivery and delaying retinal degeneration in the Cep290rd16 mice. Using the ability of Cep290rd16 mouse embryonic fibroblasts to from shorter cilia as a platform, a human CEP290 domain encoded by amino acids 580-1180 (miniCEP290580-1180) was identified that can recover the cilia length in vitro. Furthermore, subretinal injection of AAV particles carrying the cDNA expressing miniCEP290580-1180 into neonatal Cep290rd16 mice resulted in significantly improved photoreceptor survival, morphology, and function compared to control injected mice. These studies show the potential of using a truncated CEP290 to treat this fast progressing and devastating disease.
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Affiliation(s)
- Wei Zhang
- Department of Ophthalmology, UMASS Medical School, Worcester, Massachusetts
| | - Linjing Li
- Department of Ophthalmology, UMASS Medical School, Worcester, Massachusetts
| | - Qin Su
- Horae Gene Therapy Center, UMASS Medical School, Worcester, Massachusetts
| | - Guangping Gao
- Horae Gene Therapy Center, UMASS Medical School, Worcester, Massachusetts
| | - Hemant Khanna
- Department of Ophthalmology, UMASS Medical School, Worcester, Massachusetts
- Horae Gene Therapy Center, UMASS Medical School, Worcester, Massachusetts
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28
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Men CJ, Bujakowska KM, Comander J, Place E, Bedoukian EC, Zhu X, Leroy BP, Fulton AB, Pierce EA. The importance of genetic testing as demonstrated by two cases of CACNA1F-associated retinal generation misdiagnosed as LCA. Mol Vis 2017; 23:695-706. [PMID: 29062221 PMCID: PMC5640518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 10/08/2017] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To describe in detail cases with an initial diagnosis of Leber congenital amaurosis that were later found to have a hemizygous mutation in the CACNA1F gene. METHODS The patients underwent a detailed ophthalmological evaluation and full-field electroretinography (ERG). Selective targeted capture and whole-exome next-generation sequencing (NGS) were used to find the disease-causing mutations. RESULTS Patient 1 presented at age 3 months with nystagmus, normal visual attention, and a normal fundus exam. ERG responses were severely decreased. Patient 2 presented with nystagmus, severe hyperopia, esotropia, and visual acuity of 20/360 oculus dexter (OD) and 20/270 oculus sinister (OS) at age 5 months. His fundus exam showed slightly increased pigmentation around the foveae. The scotopic ERG responses were severely decreased and photopic responses mildly decreased. Based on the initial presentation, both patients received the clinical diagnosis of Leber congenital amaurosis (LCA). However, genetic testing showed no mutations in known LCA genes. Instead, broader genetic testing using NGS showed point mutations in the CACNA1F gene, which is reported to be associated with type 2 congenital stationary night blindness (CSNB2). CONCLUSIONS These two cases demonstrate the clinical overlap between LCA and CSNB in infants and young children. Genetic testing is an essential tool in these cases and provides a more accurate diagnosis and prognosis for patients with inherited retinal degenerative disorders.
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Affiliation(s)
- Clara J. Men
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Kinga M. Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Jason Comander
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Emily Place
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Emma C. Bedoukian
- Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children’s Hospital of Philadelphia, PA
| | - Xiaosong Zhu
- Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children’s Hospital of Philadelphia, PA
| | - Bart P. Leroy
- Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children’s Hospital of Philadelphia, PA,Department of Ophthalmology & Center for Medical Genetics, Ghent University Hospital & Ghent University, Ghent, Belgium
| | - Anne B. Fulton
- Department of Ophthalmology, Boston Children’s Hospital, Boston, MA
| | - Eric A. Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
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29
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Kammenga JE. The background puzzle: how identical mutations in the same gene lead to different disease symptoms. FEBS J 2017; 284:3362-3373. [PMID: 28390082 DOI: 10.1111/febs.14080] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 03/31/2017] [Accepted: 04/05/2017] [Indexed: 01/05/2023]
Abstract
Identical disease-causing mutations can lead to different symptoms in different people. The reason for this has been a puzzling problem for geneticists. Differential penetrance and expressivity of mutations has been observed within individuals with different and similar genetic backgrounds. Attempts have been made to uncover the underlying mechanisms that determine differential phenotypic effects of identical mutations through studies of model organisms. From these studies evidence is accumulating that to understand disease mechanism or predict disease prevalence, an understanding of the influence of genetic background is as important as the putative disease-causing mutations of relatively large effect. This review highlights current insights into phenotypic variation due to gene interactions, epigenetics and stochasticity in model organisms, and discusses their importance for understanding the mutational effect on disease symptoms.
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Affiliation(s)
- Jan E Kammenga
- Laboratory of Nematology, Wageningen University, The Netherlands
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30
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Gonçalves J, Pelletier L. The Ciliary Transition Zone: Finding the Pieces and Assembling the Gate. Mol Cells 2017; 40:243-253. [PMID: 28401750 PMCID: PMC5424270 DOI: 10.14348/molcells.2017.0054] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/05/2017] [Indexed: 12/23/2022] Open
Abstract
Eukaryotic cilia are organelles that project from the surface of cells to fulfill motility and sensory functions. In vertebrates, the functions of both motile and immotile cilia are critical for embryonic development and adult tissue homeostasis. Importantly, a multitude of human diseases is caused by abnormal cilia biogenesis and functions which rely on the compartmentalization of the cilium and the maintenance of its protein composition. The transition zone (TZ) is a specialized ciliary domain present at the base of the cilium and is part of a gate that controls protein entry and exit from this organelle. The relevance of the TZ is highlighted by the fact that several of its components are coded by ciliopathy genes. Here we review recent developments in the study of TZ proteomes, the mapping of individual components to the TZ structure and the establishment of the TZ as a lipid gate.
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Affiliation(s)
- João Gonçalves
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5,
Canada
| | - Laurence Pelletier
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5,
Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8,
Canada
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31
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Li L, Khanna H. Stem cells with a view: a look inside a retinal ciliopathy. Stem Cell Investig 2016; 3:62. [PMID: 27868044 DOI: 10.21037/sci.2016.09.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 09/23/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Linjing Li
- Department of Ophthalmology, UMASS Medical School, Worcester, MA 01605, USA
| | - Hemant Khanna
- Department of Ophthalmology, UMASS Medical School, Worcester, MA 01605, USA
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