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Zhang CJ, Mou H, Yuan J, Wang YH, Sun SN, Wang W, Xu ZH, Yu SJ, Jin K, Jin ZB. Effects of fluorescent protein tdTomato on mouse retina. Exp Eye Res 2024; 243:109910. [PMID: 38663720 DOI: 10.1016/j.exer.2024.109910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 02/26/2024] [Accepted: 04/22/2024] [Indexed: 04/30/2024]
Abstract
Fluorescent proteins (FPs) have been widely used to investigate cellular and molecular interactions and trace biological events in many applications. Some of the FPs have been demonstrated to cause undesirable cellular damage by light-induced ROS production in vivo or in vitro. However, it remains unknown if one of the most popular FPs, tdTomato, has similar effects in neuronal cells. In this study, we discovered that tdTomato expression led to unexpected retinal dysfunction and ultrastructural defects in the transgenic mouse retina. The retinal dysfunction mainly manifested in the reduced photopic electroretinogram (ERG) responses and decreased contrast sensitivity in visual acuity, caused by mitochondrial damages characterized with cellular redistribution, morphological modifications and molecular profiling alterations. Taken together, our findings for the first time demonstrated the retinal dysfunction and ultrastructural defects in the retinas of tdTomato-transgenic mice, calling for a more careful design and interpretation of experiments involved in FPs.
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Affiliation(s)
- Chang-Jun Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Hao Mou
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Jing Yuan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ya-Han Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Shu-Ning Sun
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Wen Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ze-Hua Xu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Si-Jian Yu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Kangxin Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
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Neuhofer CM, Prokisch H. Digenic Inheritance in Rare Disorders and Mitochondrial Disease-Crossing the Frontier to a More Comprehensive Understanding of Etiology. Int J Mol Sci 2024; 25:4602. [PMID: 38731822 PMCID: PMC11083678 DOI: 10.3390/ijms25094602] [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: 02/13/2024] [Revised: 04/10/2024] [Accepted: 04/12/2024] [Indexed: 05/13/2024] Open
Abstract
Our understanding of rare disease genetics has been shaped by a monogenic disease model. While the traditional monogenic disease model has been successful in identifying numerous disease-associated genes and significantly enlarged our knowledge in the field of human genetics, it has limitations in explaining phenomena like phenotypic variability and reduced penetrance. Widening the perspective beyond Mendelian inheritance has the potential to enable a better understanding of disease complexity in rare disorders. Digenic inheritance is the simplest instance of a non-Mendelian disorder, characterized by the functional interplay of variants in two disease-contributing genes. Known digenic disease causes show a range of pathomechanisms underlying digenic interplay, including direct and indirect gene product interactions as well as epigenetic modifications. This review aims to systematically explore the background of digenic inheritance in rare disorders, the approaches and challenges when investigating digenic inheritance, and the current evidence for digenic inheritance in mitochondrial disorders.
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Affiliation(s)
- Christiane M. Neuhofer
- Institute of Human Genetics, University Medical Center, Technical University of Munich, Trogerstr. 32, 81675 Munich, Germany
- Institute of Neurogenomics, Computational Health Center, Helmholtz Centre Munich Neuherberg, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany
- Institute of Human Genetics, Salzburger Landeskliniken, University Hospital of the Paracelsus Medical University, Müllner Hauptstraße 48, 5020 Salzburg, Austria
| | - Holger Prokisch
- Institute of Human Genetics, University Medical Center, Technical University of Munich, Trogerstr. 32, 81675 Munich, Germany
- Institute of Neurogenomics, Computational Health Center, Helmholtz Centre Munich Neuherberg, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany
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Fernández-Caballero L, Martín-Merida I, Blanco-Kelly F, Avila-Fernandez A, Carreño E, Fernandez-San Jose P, Irigoyen C, Jimenez-Rolando B, Lopez-Grondona F, Mahillo I, Martin-Gutierrez MP, Minguez P, Perea-Romero I, Del Pozo-Valero M, Riveiro-Alvarez R, Rodilla C, Rodriguez-Peña L, Sánchez-Barbero AI, Swafiri ST, Trujillo-Tiebas MJ, Zurita O, García-Sandoval B, Corton M, Ayuso C. PRPH2-Related Retinal Dystrophies: Mutational Spectrum in 103 Families from a Spanish Cohort. Int J Mol Sci 2024; 25:2913. [PMID: 38474159 PMCID: PMC10931554 DOI: 10.3390/ijms25052913] [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: 02/01/2024] [Revised: 02/26/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
PRPH2, one of the most frequently inherited retinal dystrophy (IRD)-causing genes, implies a high phenotypic variability. This study aims to analyze the PRPH2 mutational spectrum in one of the largest cohorts worldwide, and to describe novel pathogenic variants and genotype-phenotype correlations. A study of 220 patients from 103 families recruited from a database of 5000 families. A molecular diagnosis was performed using classical molecular approaches and next-generation sequencing. Common haplotypes were ascertained by analyzing single-nucleotide polymorphisms. We identified 56 variants, including 11 novel variants. Most of them were missense variants (64%) and were located in the D2-loop protein domain (77%). The most frequently occurring variants were p.Gly167Ser, p.Gly208Asp and p.Pro221_Cys222del. Haplotype analysis revealed a shared region in families carrying p.Leu41Pro or p.Pro221_Cys222del. Patients with retinitis pigmentosa presented an earlier disease onset. We describe the largest cohort of IRD families associated with PRPH2 from a single center. Most variants were located in the D2-loop domain, highlighting its importance in interacting with other proteins. Our work suggests a likely founder effect for the variants p.Leu41Pro and p.Pro221_Cys222del in our Spanish cohort. Phenotypes with a primary rod alteration presented more severe affectation. Finally, the high phenotypic variability in PRPH2 hinders the possibility of drawing genotype-phenotype correlations.
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Affiliation(s)
- Lidia Fernández-Caballero
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Inmaculada Martín-Merida
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Fiona Blanco-Kelly
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Almudena Avila-Fernandez
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ester Carreño
- Department of Ophthalmology, Fundación Jiménez Díaz University Hospital, 28040 Madrid, Spain; (E.C.); (B.J.-R.); (M.P.M.-G.); (B.G.-S.)
| | - Patricia Fernandez-San Jose
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Department of Genetics, Ramón y Cajal University Hospital, 28034 Madrid, Spain
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain
| | - Cristina Irigoyen
- Ophthalmology Service, Donostia University Hospital, 20014 Donostia-San Sebastián, Spain
| | - Belen Jimenez-Rolando
- Department of Ophthalmology, Fundación Jiménez Díaz University Hospital, 28040 Madrid, Spain; (E.C.); (B.J.-R.); (M.P.M.-G.); (B.G.-S.)
| | - Fermina Lopez-Grondona
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ignacio Mahillo
- Department of Statistics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain;
| | - María Pilar Martin-Gutierrez
- Department of Ophthalmology, Fundación Jiménez Díaz University Hospital, 28040 Madrid, Spain; (E.C.); (B.J.-R.); (M.P.M.-G.); (B.G.-S.)
| | - Pablo Minguez
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Bioinformatics Unit, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain
| | - Irene Perea-Romero
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Marta Del Pozo-Valero
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Rosa Riveiro-Alvarez
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Cristina Rodilla
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Lidya Rodriguez-Peña
- Sección de Genética Medica, Servicio de Pediatría, HCU Virgen de la Arrixaca, 30120 Murcia, Spain
| | - Ana Isabel Sánchez-Barbero
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Saoud T. Swafiri
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - María José Trujillo-Tiebas
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Olga Zurita
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Blanca García-Sandoval
- Department of Ophthalmology, Fundación Jiménez Díaz University Hospital, 28040 Madrid, Spain; (E.C.); (B.J.-R.); (M.P.M.-G.); (B.G.-S.)
| | - Marta Corton
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Carmen Ayuso
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain; (L.F.-C.); (I.M.-M.); (F.B.-K.); (A.A.-F.); (F.L.-G.); (P.M.); (C.R.); (A.I.S.-B.); (S.T.S.); (M.J.T.-T.); (O.Z.)
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
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Heath Jeffery RC, Lo J, Thompson JA, Lamey TM, McLaren TL, De Roach JN, Ayton LN, Vincent AL, Sharma A, Chen FK. Analysis of the Outer Retinal Bands in ABCA4 and PRPH2-Associated Retinopathy using OCT. Ophthalmol Retina 2024; 8:174-183. [PMID: 37209970 DOI: 10.1016/j.oret.2023.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/09/2023] [Accepted: 05/12/2023] [Indexed: 05/22/2023]
Abstract
PURPOSE To evaluate the outer retinal bands using OCT in ABCA4- and PRPH2-associated retinopathy and develop a novel imaging biomarker to differentiate between these 2 genotypes. DESIGN Multicenter case-control study. PARTICIPANTS Patients with a clinical and genetic diagnosis of ABCA4- or PRPH2-associated retinopathy and an age-matched control group. METHODS Macular OCT was used to measure the thickness of the outer retinal bands 2 and 4 by 2 independent examiners at 4 retinal loci. MAIN OUTCOME MEASURES Outcome measures included the thicknesses of band 2, band 4, and the band 2/band 4 ratio. Linear mixed modeling was used to make comparisons across the 3 groups. Receiver operating characteristic (ROC) analysis determined the optimal cutoff for the band 2/band 4 ratio to distinguish PRPH2- from ABCA4-associated retinopathy. RESULTS We included 45 patients with ABCA4 variants, 45 patients with PRPH2 variants, and 45 healthy controls. Band 2 was significantly thicker in patients with PRPH2 compared with ABCA4 (21.4 vs. 15.9 μm, P < 0.001) variants, whereas band 4 was thicker in patients with ABCA4 variants than those with PRPH2 variants (27.5 vs. 21.7 μm, P < 0.001). Similarly, the band 2/band 4 ratio was significantly different (1.0 vs. 0.6 for PRPH2 vs. ABCA4, P < 0.001). The area under the ROC curve was 0.87 for either band 2 (> 18.58 μm) or band 4 (< 26.17 μm) alone and 0.99 (95% confidence interval: 0.97-0.99) for the band 2/band 4 ratio with a cutoff threshold of 0.79, providing 100% specificity. CONCLUSIONS We report an altered outer retinal band profile whereby the band 2/band 4 ratio was able to discriminate between PRPH2- and ABCA4-associated retinopathy. This may have future clinic utility in predicting the genotype and provide further insight into the anatomic correlate of band 2. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
| | - Johnny Lo
- School of Science, Edith Cowan University, Perth, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Terri L McLaren
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Andrea L Vincent
- Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Abhishek Sharma
- Ophthalmology Department, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Western Australia, Australia; Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia.
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5
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Lewis TR, Makia MS, Castillo CM, Hao Y, Al-Ubaidi MR, Skiba NP, Conley SM, Arshavsky VY, Naash MI. ROM1 is redundant to PRPH2 as a molecular building block of photoreceptor disc rims. eLife 2023; 12:RP89444. [PMID: 37991486 PMCID: PMC10665016 DOI: 10.7554/elife.89444] [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] [Indexed: 11/23/2023] Open
Abstract
Visual signal transduction takes place within a stack of flattened membranous 'discs' enclosed within the light-sensitive photoreceptor outer segment. The highly curved rims of these discs, formed in the process of disc enclosure, are fortified by large hetero-oligomeric complexes of two homologous tetraspanin proteins, PRPH2 (a.k.a. peripherin-2 or rds) and ROM1. While mutations in PRPH2 affect the formation of disc rims, the role of ROM1 remains poorly understood. In this study, we found that the knockout of ROM1 causes a compensatory increase in the disc content of PRPH2. Despite this increase, discs of ROM1 knockout mice displayed a delay in disc enclosure associated with a large diameter and lack of incisures in mature discs. Strikingly, further increasing the level of PRPH2 rescued these morphological defects. We next showed that disc rims are still formed in a knockin mouse in which the tetraspanin body of PRPH2 was replaced with that of ROM1. Together, these results demonstrate that, despite its contribution to the formation of disc rims, ROM1 can be replaced by an excess of PRPH2 for timely enclosure of newly forming discs and establishing normal outer segment structure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of HoustonHoustonUnited States
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of HoustonHoustonUnited States
- College of Optometry, University of HoustonHoustonUnited States
| | - Nikolai P Skiba
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences CenterOklahoma CityUnited States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
| | - Muna I Naash
- Department of Biomedical Engineering, University of HoustonHoustonUnited States
- College of Optometry, University of HoustonHoustonUnited States
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Ruiz-Pastor MJ, Sánchez-Sáez X, Kutsyr O, Albertos-Arranz H, Sánchez-Castillo C, Ortuño-Lizarán I, Martínez-Gil N, Vidal-Gil L, Méndez L, Sánchez-Martín M, Maneu V, Lax P, Cuenca N. Prph2 knock-in mice recapitulate human central areolar choroidal dystrophy retinal degeneration and exhibit aberrant synaptic remodeling and microglial activation. Cell Death Dis 2023; 14:711. [PMID: 37914688 PMCID: PMC10620171 DOI: 10.1038/s41419-023-06243-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/16/2023] [Accepted: 10/20/2023] [Indexed: 11/03/2023]
Abstract
Central areolar choroidal dystrophy is an inherited disorder characterized by progressive choriocapillaris atrophy and retinal degeneration and is usually associated with mutations in the PRPH2 gene. We aimed to generate and characterize a mouse model with the p.Arg195Leu mutation previously described in patients. Heterozygous (Prph2WT/KI) and homozygous (Prph2KI/KI) mice were generated using the CRISPR/Cas9 system to introduce the p.Arg195Leu mutation. Retinal function was assessed by electroretinography and optomotor tests at 1, 3, 6, 9, 12, and 20 months of age. The structural integrity of the retinas was evaluated at the same ages using optical coherence tomography. Immunofluorescence and transmission electron microscopy images of the retina were also analyzed. Genetic sequencing confirmed that both Prph2WT/KI and Prph2KI/KI mice presented the p.Arg195Leu mutation. A progressive loss of retinal function was found in both mutant groups, with significantly reduced visual acuity from 3 months of age in Prph2KI/KI mice and from 6 months of age in Prph2WT/KI mice. Decreased amplitudes in the electroretinography responses were observed from 1 month of age in Prph2KI/KI mice and from 6 months of age in Prph2WT/KI mice. Morphological analysis of the retinas correlated with functional findings, showing a progressive decrease in retinal thickness of mutant mice, with earlier and more severe changes in the homozygous mutant mice. We corroborated the alteration of the outer segment structure, and we found changes in the synaptic connectivity in the outer plexiform layer as well as gliosis and signs of microglial activation. The new Prph2WT/KI and Prph2KI/KI murine models show a pattern of retinal degeneration similar to that described in human patients with central areolar choroidal dystrophy and appear to be good models to study the mechanisms involved in the onset and progression of the disease, as well as to test the efficacy of new therapeutic strategies.
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Affiliation(s)
| | - Xavier Sánchez-Sáez
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| | - Oksana Kutsyr
- Optics, Pharmacology, and Anatomy, University of Alicante, Alicante, Spain
| | | | | | | | | | - Lorena Vidal-Gil
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| | - Lucía Méndez
- Transgenic Facility and Department of Medicine, University of Salamanca, Salamanca, Spain
| | - Manuel Sánchez-Martín
- Transgenic Facility and Department of Medicine, University of Salamanca, Salamanca, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
| | - Victoria Maneu
- Optics, Pharmacology, and Anatomy, University of Alicante, Alicante, Spain
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain
| | - Pedro Lax
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain.
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain.
| | - Nicolás Cuenca
- Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain.
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain.
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7
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Lewis TR, Makia MS, Castillo CM, Hao Y, Al-Ubaidi MR, Skiba NP, Conley SM, Arshavsky VY, Naash MI. ROM1 is redundant to PRPH2 as a molecular building block of photoreceptor disc rims. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.02.547380. [PMID: 37693615 PMCID: PMC10491102 DOI: 10.1101/2023.07.02.547380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Visual signal transduction takes place within a stack of flattened membranous "discs" enclosed within the light-sensitive photoreceptor outer segment. The highly curved rims of these discs, formed in the process of disc enclosure, are fortified by large hetero-oligomeric complexes of two homologous tetraspanin proteins, PRPH2 (a.k.a. peripherin-2 or rds) and ROM1. While mutations in PRPH2 affect the formation of disc rims, the role of ROM1 remains poorly understood. In this study, we found that the knockout of ROM1 causes a compensatory increase in the disc content of PRPH2. Despite this increase, discs of ROM1 knockout mice displayed a delay in disc enclosure associated with a large diameter and lack of incisures in mature discs. Strikingly, further increasing the level of PRPH2 rescued these morphological defects. We next showed that disc rims are still formed in a knockin mouse in which the tetraspanin body of PRPH2 was replaced with that of ROM1. Together, these results demonstrate that, despite its contribution to the formation of disc rims, ROM1 can be replaced by an excess of PRPH2 for timely enclosure of newly forming discs and establishing normal outer segment structure.
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Affiliation(s)
- Tylor R. Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Mustafa S. Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA, 77204
| | - Carson M. Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA, 77204
- College of Optometry, University of Houston, Houston, TX, USA, 77204
| | - Nikolai P. Skiba
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA, 73104
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA, 77204
- College of Optometry, University of Houston, Houston, TX, USA, 77204
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8
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Parmann R, Tsang SH, Sparrow JR. Primary versus Secondary Elevations in Fundus Autofluorescence. Int J Mol Sci 2023; 24:12327. [PMID: 37569703 PMCID: PMC10419315 DOI: 10.3390/ijms241512327] [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: 06/08/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
The method of quantitative fundus autofluorescence (qAF) can be used to assess the levels of bisretinoids in retinal pigment epithelium (RPE) cells so as to aid the interpretation and management of a variety of retinal conditions. In this review, we focused on seven retinal diseases to highlight the possible pathways to increased fundus autofluorescence. ABCA4- and RDH12-associated diseases benefit from known mechanisms whereby gene malfunctioning leads to elevated bisretinoid levels in RPE cells. On the other hand, peripherin2/RDS-associated disease (PRPH2/RDS), retinitis pigmentosa (RP), central serous chorioretinopathy (CSC), acute zonal occult outer retinopathy (AZOOR), and ceramide kinase like (CERKL)-associated retinal degeneration all express abnormally high fundus autofluorescence levels without a demonstrated pathophysiological pathway for bisretinoid elevation. We suggest that, while a known link from gene mutation to increased production of bisretinoids (as in ABCA4- and RDH12-associated diseases) causes primary elevation in fundus autofluorescence, a secondary autofluorescence elevation also exists, where an impairment and degeneration of photoreceptor cells by various causes leads to an increase in bisretinoid levels in RPE cells.
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Affiliation(s)
- Rait Parmann
- Departments of Ophthalmology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
| | - Stephen H. Tsang
- Departments of Ophthalmology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
- Departments of Pathology and Cell Biology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
| | - Janet R. Sparrow
- Departments of Ophthalmology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
- Departments of Pathology and Cell Biology, Columbia University, 635 W. 165th Street, New York, NY 10032, USA
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9
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Ikelle L, Makia M, Lewis T, Crane R, Kakakhel M, Conley SM, Birtley JR, Arshavsky VY, Al-Ubaidi MR, Naash MI. Comparative study of PRPH2 D2 loop mutants reveals divergent disease mechanism in rods and cones. Cell Mol Life Sci 2023; 80:214. [PMID: 37466729 PMCID: PMC10356684 DOI: 10.1007/s00018-023-04851-3] [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: 01/25/2023] [Revised: 05/10/2023] [Accepted: 06/28/2023] [Indexed: 07/20/2023]
Abstract
Mutations in the photoreceptor-specific tetraspanin gene peripherin-2 (PRPH2) lead to widely varying forms of retinal degeneration ranging from retinitis pigmentosa to macular dystrophy. Both inter- and intra-familial phenotypic heterogeneity has led to much interest in uncovering the complex pathogenic mechanisms of PRPH2-associated disease. Majority of disease-causing mutations in PRPH2 reside in the second intradiscal loop, wherein seven cysteines control protein folding and oligomerization. Here, we utilize knockin models to evaluate the role of three D2 loop cysteine mutants (Y141C, C213Y and C150S), alone or in combination. We elucidated how these mutations affect PRPH2 properties, including oligomerization and subcellular localization, and contribute to disease processes. Results from our structural, functional and molecular studies revealed that, in contrast to our understanding from prior investigations, rods are highly affected by PRPH2 mutations interfering with oligomerization and not merely by the haploinsufficiency associated with these mutations. On the other hand, cones are less affected by the toxicity of the mutant protein and significantly reduced protein levels, suggesting that knockdown therapeutic strategies may sustain cone functionality for a longer period. This observation provides useful data to guide and simplify the current development of effective therapeutic approaches for PRPH2-associated diseases that combine knockdown with high levels of gene supplementation needed to generate prolonged rod improvement.
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Affiliation(s)
- Larissa Ikelle
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Mustafa Makia
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Tylor Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Ryan Crane
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | | | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA.
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA.
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10
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Lewis TR, Phan S, Castillo CM, Kim KY, Coppenrath K, Thomas W, Hao Y, Skiba NP, Horb ME, Ellisman MH, Arshavsky VY. Photoreceptor disc incisures form as an adaptive mechanism ensuring the completion of disc enclosure. eLife 2023; 12:e89160. [PMID: 37449984 PMCID: PMC10361718 DOI: 10.7554/elife.89160] [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: 05/05/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023] Open
Abstract
The first steps of vision take place within a stack of tightly packed disc-shaped membranes, or 'discs', located in the outer segment compartment of photoreceptor cells. In rod photoreceptors, discs are enclosed inside the outer segment and contain deep indentations in their rims called 'incisures'. The presence of incisures has been documented in a variety of species, yet their role remains elusive. In this study, we combined traditional electron microscopy with three-dimensional electron tomography to demonstrate that incisures are formed only after discs become completely enclosed. We also observed that, at the earliest stage of their formation, discs are not round as typically depicted but rather are highly irregular in shape and resemble expanding lamellipodia. Using genetically manipulated mice and frogs and measuring outer segment protein abundances by quantitative mass spectrometry, we further found that incisure size is determined by the molar ratio between peripherin-2, a disc rim protein critical for the process of disc enclosure, and rhodopsin, the major structural component of disc membranes. While a high perpherin-2 to rhodopsin ratio causes an increase in incisure size and structural complexity, a low ratio precludes incisure formation. Based on these data, we propose a model whereby normal rods express a modest excess of peripherin-2 over the amount required for complete disc enclosure in order to ensure that this important step of disc formation is accomplished. Once the disc is enclosed, the excess peripherin-2 incorporates into the rim to form an incisure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Sebastien Phan
- National Center for Microscopy and Imaging Research, School of Medicine, University of California, San DiegoLa JollaUnited States
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, School of Medicine, University of California, San DiegoLa JollaUnited States
| | - Kelsey Coppenrath
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus ResourceWoods HoleUnited States
| | - William Thomas
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus ResourceWoods HoleUnited States
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Nikolai P Skiba
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Marko E Horb
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus ResourceWoods HoleUnited States
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, School of Medicine, University of California, San DiegoLa JollaUnited States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
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11
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Lewis TR, Phan S, Castillo CM, Kim KY, Coppenrath K, Thomas W, Hao Y, Skiba NP, Horb ME, Ellisman MH, Arshavsky VY. Photoreceptor disc incisures form as an adaptive mechanism ensuring the completion of disc enclosure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.06.535932. [PMID: 37066355 PMCID: PMC10104153 DOI: 10.1101/2023.04.06.535932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
The first steps of vision take place within a stack of tightly packed disc-shaped membranes, or "discs", located in the outer segment compartment of photoreceptor cells. In rod photoreceptors, discs are enclosed inside the outer segment and contain deep indentations in their rims called "incisures". The presence of incisures has been documented in a variety of species, yet their role remains elusive. In this study, we combined traditional electron microscopy with three-dimensional electron tomography to demonstrate that incisures are formed only after discs become completely enclosed. We also observed that, at the earliest stage of their formation, discs are not round as typically depicted but rather are highly irregular in shape and resemble expanding lamellipodia. Using genetically manipulated mice and frogs and measuring outer segment protein abundances by quantitative mass spectrometry, we further found that incisure size is determined by the molar ratio between peripherin-2, a disc rim protein critical for the process of disc enclosure, and rhodopsin, the major structural component of disc membranes. While a high perpherin-2 to rhodopsin ratio causes an increase in incisure size and structural complexity, a low ratio precludes incisure formation. Based on these data, we propose a model whereby normal rods express a modest excess of peripherin-2 over the amount required for complete disc enclosure in order to ensure that this important step of disc formation is accomplished. Once the disc is enclosed, the excess peripherin-2 incorporates into the rim to form an incisure.
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12
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Lewis TR, Al-Ubaidi MR, Naash MI, Arshavsky VY. The Role of Peripherin-2/ROM1 Complexes in Photoreceptor Outer Segment Disc Morphogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:277-281. [PMID: 37440045 DOI: 10.1007/978-3-031-27681-1_40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
The light-sensitive outer segment organelle of photoreceptor cells contains a stack of hundreds of flat, disc-shaped membranes called discs. The rims of these discs contain a photoreceptor-specific tetraspanin protein peripherin-2 (also known as rds or PRPH2). Mutations in the PRPH2 gene lead to a wide variety of inherited retinal degenerations in humans. The vast majority of these mutations occur within a large, intradiscal loop of peripherin-2, known as the D2 loop. The D2 loop mediates well-established intermolecular interactions of peripherin-2 molecules among themselves and a homologous protein ROM1. These interactions lead to the formation of large, highly ordered oligomers. In this chapter, we discuss the supramolecular organization of peripherin-2/ROM1 complexes and their contribution to the process of outer segment disc morphogenesis and enclosure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA.
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, College of Engineering, University of Houston, Houston, TX, USA
- College of Optometry, University of Houston, Houston, TX, USA
| | - Muna I Naash
- Department of Biomedical Engineering, College of Engineering, University of Houston, Houston, TX, USA
- College of Optometry, University of Houston, Houston, TX, USA
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
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13
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Bianco L, Arrigo A, Antropoli A, Saladino A, Spiga I, Patricelli MG, Bandello F, Carrera P, Battaglia Parodi M. PRPH2-Associated Retinopathy: Novel Variants and Genotype-Phenotype Correlations. Ophthalmol Retina 2022; 7:450-461. [PMID: 36563963 DOI: 10.1016/j.oret.2022.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/01/2022] [Accepted: 12/13/2022] [Indexed: 12/25/2022]
Abstract
PURPOSE A broad spectrum of autosomal-dominant inherited retinal diseases (IRDs), ranging from mild macular pattern dystrophy to severe cone-rod degeneration, is associated with PRPH2 variants (peripherinopathies). We present detailed clinical and molecular characterization of patients affected by peripherinopathies, aiming to expand the mutational spectrum, and propose novel genotype-phenotype correlations. DESIGN Observational, retrospective case series. PARTICIPANTS Patients with an IRD related to a molecularly proven PRPH2 variant. METHODS Data from ophthalmic examinations and retinal imaging were collected for each follow-up visit. The standard imaging protocol included OCT, blue-light autofluorescence, near-infrared autofluorescence, and ultra-widefield fundus imaging. Genetic analysis was performed with a genomic approach by next-generation sequencing. MAIN OUTCOME MEASURES Results of ophthalmic examination, retinal imaging, and molecular genetic analysis. RESULTS Overall, a total of 19 patients with an IRD and a (likely) pathogenic PRPH2 variant were identified. Their age at presentation had a median of 48 years, whereas the symptomatic disease onset was in their 30s or 40s in 74% of cases. The median follow-up time was 4 years. Clinically, 6 patients were diagnosed with cone-rod dystrophy and 13 with pattern dystrophy. Among the 13 PRPH2 pathogenic variants identified in our cohort, 7 were missense, 3 nonsense, 2 frame shifting, and 1 splice site. Missense variants in the D2 loop were associated with cone-rod dystrophies and poor visual prognosis, whereas predicted loss-of-function alleles with pattern dystrophies and retention of a good visual function into adulthood. Overall, the following 7 variants were novel and never associated to a clinical phenotype: c.68delT, c.290G>A, c.413T>G, c.642C>G, c.702_706dupCAGTT, c.771_772delinsGA, and c.850C>G. CONCLUSIONS Here, we report the findings of a retrospective case series that provided a detailed clinical and molecular characterization of 19 patients harboring 13 different PRPH2 pathogenic variants, 7 of which were previously unreported, expanding the mutational spectrum of the PRPH2 gene. Loss-of-function variants might be preferentially associated with mild-pattern dystrophies, whereas missense dominant-negative variants might be preferentially associated with severely blinding cone-rod degenerations. Further studies are needed to better define the pathogenetic mechanisms and the functional effects of most variants to allow the development of successful gene therapy. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Lorenzo Bianco
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Arrigo
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy.
| | - Alessio Antropoli
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Andrea Saladino
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Ivana Spiga
- Laboratory of Clinical Genomics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Francesco Bandello
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Paola Carrera
- Laboratory of Clinical Genomics, IRCCS San Raffaele Scientific Institute, Milan, Italy; Unit of Genomics for Human Disease Diagnosis, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maurizio Battaglia Parodi
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
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14
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Xiao X, Ling F, Chen CB, Liang J, Cao Y, Xu Y, Chen H. PRPF31 interacts with PRPH2 confirmed by co-immunoprecipitation and co-localization. Biochem Biophys Res Commun 2022; 629:12-16. [PMID: 36088804 DOI: 10.1016/j.bbrc.2022.08.090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/22/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022]
Abstract
Both PRPF31 and PRPH2 are the causative genes for retinitis pigmentosa. And both of them are associated with the balance of rhodopsin. In this study, we aim to investigate the co-expression and interaction of PRPF31 and PRPH2. We used PRPF31-eGFP, PRPF31-3xFlag and PRPH2-mCherry vectors were transfected into HEK293T and APRE-19 cells. Immunoblotting and co-immunoprecipitation (Co-IP) were used for gene expression validation and protein interaction. Immunofluorescence staining assay was used to test the co-localization analysis of PRPF31 and PRPH2. Co-IP experiments showed that PRPF31 could be pulled down with an anti-PRPH2 antibody. There was co-localization between PRPF31 and PRPH2 in HEK293T, APRE-19 and mouse retina. The Co-IP and co-localization experiments suggest that PRPF31 interacted with PRPH2.
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Affiliation(s)
- Xiaoqiang Xiao
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Fangyi Ling
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Chong-Bo Chen
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Jiajian Liang
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Yingjie Cao
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Yanxuan Xu
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China
| | - Haoyu Chen
- Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China.
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15
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Antonelli G, Parravano M, Barbano L, Costanzo E, Bertelli M, Medori MC, Parisi V, Ziccardi L. Multimodal Study of PRPH2 Gene-Related Retinal Phenotypes. Diagnostics (Basel) 2022; 12:diagnostics12081851. [PMID: 36010202 PMCID: PMC9406607 DOI: 10.3390/diagnostics12081851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 11/25/2022] Open
Abstract
PRPH2 gene mutations are frequently found in inherited retinal dystrophies (IRD) and are associated with a wide spectrum of clinical phenotypes. We studied 28 subjects affected by IRD carrying pathogenic PRPH2 mutations, belonging to 11 unrelated families. Functional tests (best-corrected visual acuity measurement, chromatic test, visual field, full-field, 30 Hz flicker, and multifocal electroretinogram), morphological retino-choroidal imaging (optical coherence tomography, optical coherence tomography angiography, and fundus autofluorescence), and clinical data were collected and analyzed. Common primary complaints, with onset in their 40s, were visual acuity reduction and abnormal dark adaptation. Visual acuity ranged from light perception to 20/20 Snellen. Visual field peripheral constriction and central scotoma were found. Chromatic sense was reduced in one third of patients. Electrophysiological tests were abnormal in most of the patients. Choroidal neovascular lesions were detected in five patients. Three novel PRPH2 variants were found in four different families. Based on the present multimodal study, we identified seven distinct PRPH2 phenotypes in 11 unrelated families carrying either different mutations or the same mutation, both within the same family or among them. Fundus autofluorescence modality turned out to be the most adequate imaging method for early recognition of this dystrophy, and the optical coherence tomography angiography was highly informative to promptly detect choroidal neovascularization, even in the presence of the extensive chorioretinal atrophy phenotype.
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Affiliation(s)
- Giulio Antonelli
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Mariacristina Parravano
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
- Correspondence: ; Tel.: +39-067-705-2963
| | - Lucilla Barbano
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Eliana Costanzo
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Matteo Bertelli
- MAGI’S LAB, Via Delle Maioliche 57/D, 38068 Rovereto, Italy; (M.B.); (M.C.M.)
- MAGI EUREGIO, Via Maso Delle Pieve 60/A, 39100 Bolzano, Italy
- MAGISNAT, Atlanta Tech Park, 107 Technology, Parkway, Peachtree Corners, GA 30092, USA
| | - Maria Chiara Medori
- MAGI’S LAB, Via Delle Maioliche 57/D, 38068 Rovereto, Italy; (M.B.); (M.C.M.)
| | - Vincenzo Parisi
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Lucia Ziccardi
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
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16
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Conley SM, McClard CK, Mwoyosvi ML, Alkadhem N, Radojevic B, Klein M, Birch D, Ellis A, Icks SW, Guddanti T, Bennett LD. Delineating the Clinical Phenotype of Patients With the c.629C>G, p.Pro210Arg Mutation in Peripherin-2. Invest Ophthalmol Vis Sci 2022; 63:19. [PMID: 35861669 PMCID: PMC9315069 DOI: 10.1167/iovs.63.8.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose More than 200 different mutations in peripherin-2 (PRPH2) are associated with multiple subtypes of inherited retinal diseases (IRDs), including retinitis pigmentosa and cone or macular diseases. Our goal was to understand how the poorly characterized PRPH2 mutation p.Pro210Arg (P210R) affects visual function and retinal structure as well as gain insight into the mechanism driving the clinical pathology. Methods Eleven patients had clinical assessments including best-corrected visual acuity (BCVA), full field and multifocal electroretinography (ERG), static (spot size V) and kinetic perimetry (Octopus 900), and dark-adapted chromatic (DAC; Medmont; spot size V) perimetry. Images were acquired with the Optos ultra-wide field camera and spectral-domain optical coherence tomography (SD-OCT). Molecular characteristics of the P210R mutant protein were evaluated in vitro. Results Patients with the P210R mutation had BCVA (Snellen) ranging from 20/15 to 20/80. Perimetry showed a reduction in sensitivity, while ERG findings suggested that cone function was more impaired than rod function. Scotomas were identified corresponding to atrophic retinal lesions. Imaging revealed heterogeneous outer retinal changes such as hyperfluorescent flecks, hypo-autofluorescence (AF) regions of atrophy, and thinning of the photoreceptor layer on SD-OCT. In vitro findings suggested that P210R-Prph2 retains the ability to interact with binding partner Rom1 but abnormally accumulates in the endoplasmic reticulum (ER), suggesting the protein does not fold properly. Conclusions Rod and cone sensitivities were decreased in subjects with the P210R mutation in PRPH2. There was scotomatous vision loss that occurred within the macula, likely due to atrophy that occurs after drusen have formed and have begun to resolve. This suggests that although rod and cone photoreceptors are dependent on PRPH2, preventing blindness in this specific subgroup of patients could involve therapeutics that impede the formation or lifecycle of drusen.
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Affiliation(s)
- Shannon M Conley
- University of Oklahoma Health Sciences Center, Department of Cell Biology, Oklahoma City, Oklahoma, United States
| | - Cynthia K McClard
- University of Oklahoma Health Sciences Center, Department of Ophthalmology, Oklahoma City, Oklahoma, United States.,Dean McGee Eye Institute, Oklahoma City, Oklahoma City, Oklahoma, United States
| | - Maggie L Mwoyosvi
- University of Oklahoma Health Sciences Center, Department of Cell Biology, Oklahoma City, Oklahoma, United States
| | - Niyaf Alkadhem
- University of Oklahoma Health Sciences Center, Department of Ophthalmology, Oklahoma City, Oklahoma, United States
| | - Bojana Radojevic
- University of Oklahoma Health Sciences Center, Department of Ophthalmology, Oklahoma City, Oklahoma, United States
| | - Martin Klein
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - David Birch
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Ashley Ellis
- Dean McGee Eye Institute, Oklahoma City, Oklahoma City, Oklahoma, United States
| | - Sonny W Icks
- Dean McGee Eye Institute, Oklahoma City, Oklahoma City, Oklahoma, United States
| | - Tejesh Guddanti
- University of Oklahoma Health Sciences Center, College of Medicine, Oklahoma City, Oklahoma, United States
| | - Lea D Bennett
- University of Oklahoma Health Sciences Center, Department of Ophthalmology, Oklahoma City, Oklahoma, United States.,Dean McGee Eye Institute, Oklahoma City, Oklahoma City, Oklahoma, United States
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17
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Bhardwaj A, Yadav A, Yadav M, Tanwar M. Genetic dissection of non-syndromic retinitis pigmentosa. Indian J Ophthalmol 2022; 70:2355-2385. [PMID: 35791117 PMCID: PMC9426071 DOI: 10.4103/ijo.ijo_46_22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Retinitis pigmentosa (RP) belongs to a group of pigmentary retinopathies. It is the most common form of inherited retinal dystrophy, characterized by progressive degradation of photoreceptors that leads to nyctalopia, and ultimately, complete vision loss. RP is distinguished by the continuous retinal degeneration that progresses from the mid-periphery to the central and peripheral retina. RP was first described and named by Franciscus Cornelius Donders in the year 1857. It is one of the leading causes of bilateral blindness in adults, with an incidence of 1 in 3000 people worldwide. In this review, we are going to focus on the genetic heterogeneity of this disease, which is provided by various inheritance patterns, numerosity of variations and inter-/intra-familial variations based upon penetrance and expressivity. Although over 90 genes have been identified in RP patients, the genetic cause of approximately 50% of RP cases remains unknown. Heterogeneity of RP makes it an extremely complicated ocular impairment. It is so complicated that it is known as “fever of unknown origin”. For prognosis and proper management of the disease, it is necessary to understand its genetic heterogeneity so that each phenotype related to the various genetic variations could be treated.
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Affiliation(s)
- Aarti Bhardwaj
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Anshu Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Manoj Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Mukesh Tanwar
- Department of Genetics, M. D. University, Rohtak, Haryana, India
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18
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Carugo O. Survey of the Intermolecular Disulfide Bonds Observed in Protein Crystal Structures Deposited in the Protein Data Bank. LIFE (BASEL, SWITZERLAND) 2022; 12:life12070986. [PMID: 35888076 PMCID: PMC9323673 DOI: 10.3390/life12070986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 11/29/2022]
Abstract
About 5% of the disulfide bonds (DBs) observed in the Protein Data Bank bridge two protein chains. Several of their features were comprehensively analyzed, resulting in a structural atlas of the intermolecular DBs. The analysis was performed on a very large set of data extracted from the Protein Data Bank, according to the RaSPDB procedure. It was observed that the two chains tend to have different sequences and belong to the same structural class. Intermolecular DBs tend to be more solvent accessible and less distorted from the most stable conformation than intermolecular DBs while showing similar B-factors. They tend to occur in beta strands and in mainly-beta structures. These and other data should prove useful in protein modelling and design.
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Affiliation(s)
- Oliviero Carugo
- Department of Chemistry, University of Pavia, 27100 Pavia, Italy;
- Italy & Max Perutz Labs, Department of Structural and Computational Biology, University of Vienna, 1010 Wien, Austria
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19
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Liu W, Liu S, Li P, Yao K. Retinitis Pigmentosa: Progress in Molecular Pathology and Biotherapeutical Strategies. Int J Mol Sci 2022; 23:ijms23094883. [PMID: 35563274 PMCID: PMC9101511 DOI: 10.3390/ijms23094883] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa (RP) is genetically heterogeneous retinopathy caused by photoreceptor cell death and retinal pigment epithelial atrophy that eventually results in blindness in bilateral eyes. Various photoreceptor cell death types and pathological phenotypic changes that have been disclosed in RP demand in-depth research of its pathogenic mechanism that may account for inter-patient heterogeneous responses to mainstream drug treatment. As the primary method for studying the genetic characteristics of RP, molecular biology has been widely used in disease diagnosis and clinical trials. Current technology iterations, such as gene therapy, stem cell therapy, and optogenetics, are advancing towards precise diagnosis and clinical applications. Specifically, technologies, such as effective delivery vectors, CRISPR/Cas9 technology, and iPSC-based cell transplantation, hasten the pace of personalized precision medicine in RP. The combination of conventional therapy and state-of-the-art medication is promising in revolutionizing RP treatment strategies. This article provides an overview of the latest research on the pathogenesis, diagnosis, and treatment of retinitis pigmentosa, aiming for a convenient reference of what has been achieved so far.
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20
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Wu W, Takahashi Y, Shin HY, Ma X, Moiseyev G, Ma JX. The interplay of environmental luminance and genetics in the retinal dystrophy induced by the dominant RPE65 mutation. Proc Natl Acad Sci U S A 2022; 119:e2115202119. [PMID: 35271391 PMCID: PMC8931212 DOI: 10.1073/pnas.2115202119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 01/11/2022] [Indexed: 01/09/2023] Open
Abstract
SignificanceIn humans, genetic mutations in the retinal pigment epithelium (RPE) 65 are associated with blinding diseases, for which there is no effective therapy alleviating progressive retinal degeneration in affected patients. Our findings uncovered that the increased free opsin caused by enhancing the ambient light intensity increased retinal activation, and when compounded with the RPE visual cycle dysfunction caused by the heterozygous D477G mutation and aggregation, led to the onset of retinal degeneration.
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Affiliation(s)
- Wenjing Wu
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Yusuke Takahashi
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Henry Younghwa Shin
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Xiang Ma
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Gennadiy Moiseyev
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Jian-Xing Ma
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
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21
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Zernant J, Lee W, Wang J, Goetz K, Ullah E, Nagasaki T, Su PY, Fishman GA, Tsang SH, Tumminia SJ, Brooks BP, Hufnagel RB, Chen R, Allikmets R. Rare and common variants in ROM1 and PRPH2 genes trans-modify Stargardt/ABCA4 disease. PLoS Genet 2022; 18:e1010129. [PMID: 35353811 PMCID: PMC9000055 DOI: 10.1371/journal.pgen.1010129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/11/2022] [Accepted: 03/02/2022] [Indexed: 11/18/2022] Open
Abstract
Over 1,500 variants in the ABCA4 locus cause phenotypes ranging from severe, early-onset retinal degeneration to very late-onset maculopathies. The resulting ABCA4/Stargardt disease is the most prevalent Mendelian eye disorder, although its underlying clinical heterogeneity, including penetrance of many alleles, are not well-understood. We hypothesized that a share of this complexity is explained by trans-modifiers, i.e., variants in unlinked loci, which are currently unknown. We sought to identify these by performing exome sequencing in a large cohort for a rare disease of 622 cases and compared variation in seven genes known to clinically phenocopy ABCA4 disease to cohorts of ethnically matched controls. We identified a significant enrichment of variants in 2 out of the 7 genes. Moderately rare, likely functional, variants, at the minor allele frequency (MAF) <0.005 and CADD>25, were enriched in ROM1, where 1.3% of 622 patients harbored a ROM1 variant compared to 0.3% of 10,865 controls (p = 2.41E04; OR 3.81 95% CI [1.77; 8.22]). More importantly, analysis of common variants (MAF>0.1) identified a frequent haplotype in PRPH2, tagged by the p.Asp338 variant with MAF = 0.21 in the matched general population that was significantly increased in the patient cohort, MAF 0.25, p = 0.0014. Significant differences were also observed between ABCA4 disease subgroups. In the late-onset subgroup, defined by the hypomorphic p.Asn1868Ile variant and including c.4253+43G>A, the allele frequency for the PRPH2 p.Asp338 variant was 0.15 vs 0.27 in the remaining cohort, p = 0.00057. Known functional data allowed suggesting a mechanism by which the PRPH2 haplotype influences the ABCA4 disease penetrance. These associations were replicated in an independent cohort of 408 patients. The association was highly statistically significant in the combined cohorts of 1,030 cases, p = 4.00E-05 for all patients and p = 0.00014 for the hypomorph subgroup, suggesting a substantial trans-modifying role in ABCA4 disease for both rare and common variants in two unlinked loci.
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Affiliation(s)
- Jana Zernant
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Winston Lee
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
- Department of Genetics & Development, Columbia University, New York, New York, United States of America
| | - Jun Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kerry Goetz
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Ehsan Ullah
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Takayuki Nagasaki
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Pei-Yin Su
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Gerald A. Fishman
- The Pangere Center for Inherited Retinal Diseases, The Chicago Lighthouse, Chicago, Illinois, United States of America
| | - Stephen H. Tsang
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
- Department of Pathology & Cell Biology, Columbia University, New York, New York, United States of America
| | - Santa J. Tumminia
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Brian P. Brooks
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Robert B. Hufnagel
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
- Department of Pathology & Cell Biology, Columbia University, New York, New York, United States of America
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22
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Pöge M, Mahamid J, Imanishi SS, Plitzko JM, Palczewski K, Baumeister W. Determinants shaping the nanoscale architecture of the mouse rod outer segment. eLife 2021; 10:e72817. [PMID: 34931611 PMCID: PMC8758146 DOI: 10.7554/elife.72817] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/09/2021] [Indexed: 12/02/2022] Open
Abstract
The unique membrane organization of the rod outer segment (ROS), the specialized sensory cilium of rod photoreceptor cells, provides the foundation for phototransduction, the initial step in vision. ROS architecture is characterized by a stack of identically shaped and tightly packed membrane disks loaded with the visual receptor rhodopsin. A wide range of genetic aberrations have been reported to compromise ROS ultrastructure, impairing photoreceptor viability and function. Yet, the structural basis giving rise to the remarkably precise arrangement of ROS membrane stacks and the molecular mechanisms underlying genetically inherited diseases remain elusive. Here, cryo-electron tomography (cryo-ET) performed on native ROS at molecular resolution provides insights into key structural determinants of ROS membrane architecture. Our data confirm the existence of two previously observed molecular connectors/spacers which likely contribute to the nanometer-scale precise stacking of the ROS disks. We further provide evidence that the extreme radius of curvature at the disk rims is enforced by a continuous supramolecular assembly composed of peripherin-2 (PRPH2) and rod outer segment membrane protein 1 (ROM1) oligomers. We suggest that together these molecular assemblies constitute the structural basis of the highly specialized ROS functional architecture. Our Cryo-ET data provide novel quantitative and structural information on the molecular architecture in ROS and substantiate previous results on proposed mechanisms underlying pathologies of certain PRPH2 mutations leading to blindness.
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Affiliation(s)
- Matthias Pöge
- Max Planck Institute of Biochemistry, Department of Molecular Structural BiologyMartinsriedGermany
| | - Julia Mahamid
- Max Planck Institute of Biochemistry, Department of Molecular Structural BiologyMartinsriedGermany
| | - Sanae S Imanishi
- Eugene and Marilyn Glick Eye Institute and the Department of Ophthalmology, Indiana University School of MedicineyIndianapolisUnited States
| | - Jürgen M Plitzko
- Max Planck Institute of Biochemistry, Department of Molecular Structural BiologyMartinsriedGermany
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, Center for Translational Vision Research, Department of Physiology & Biophysics, Department of Chemistry, Department of Molecular Biology and BiochemistryIrvineUnited States
| | - Wolfgang Baumeister
- Max Planck Institute of Biochemistry, Department of Molecular Structural BiologyMartinsriedGermany
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23
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Xiao YS, Liang J, Gao M, Sun JR, Liu Y, Chen JQ, Zhao XH, Wang YM, Chen YH, Wang YW, Wan XL, Luo XT, Sun XD. Deletion of prominin-1 in mice results in disrupted photoreceptor outer segment protein homeostasis. Int J Ophthalmol 2021; 14:1334-1344. [PMID: 34540608 PMCID: PMC8403851 DOI: 10.18240/ijo.2021.09.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/21/2021] [Indexed: 11/23/2022] Open
Abstract
AIM To illustrate the underlying mechanism how prominin-1 (also known as Prom1) mutation contribute to progressive photoreceptor degeneration. METHODS A CRISPR-mediated Prom1 knockout (Prom1-KO) mice model in the C57BL/6 was generated and the photoreceptor degeneration phenotypes by means of structural and functional tests were demonstrated. Immunohistochemistry and immunoblot analysis were performed to reveal the localization and quantity of related outer segment (OS) proteins. RESULTS The Prom1-KO mice developed the photoreceptor degeneration phenotype including the decreased outer nuclear layer (ONL) thickness and compromised electroretinogram amplitude. Immunohistochemistry analysis revealed impaired trafficking of photoreceptor OS proteins. Immunoblot data demonstrated decreased photoreceptor OS proteins. CONCLUSION Prom1 deprivation causes progressive photoreceptor degeneration. Prom1 is essential for maintaining normal trafficking and normal quantity of photoreceptor OS proteins. The new light is shed on the pathogenic mechanism underlying photoreceptor degeneration caused by Prom1 mutation.
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Affiliation(s)
- Yu-Shu Xiao
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Jian Liang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
- Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China
| | - Min Gao
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Jun-Ran Sun
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Yang Liu
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Jie-Qiong Chen
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Xiao-Huan Zhao
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Yi-Min Wang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Yu-Hong Chen
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Yu-Wei Wang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Xiao-Ling Wan
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
- Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China
| | - Xue-Ting Luo
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
- Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China
| | - Xiao-Dong Sun
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
- Shanghai Key Laboratory of Fundus Diseases, Shanghai 200080, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
- National Clinical Research Center for Ophthalmic Diseases, Shanghai 200080, China
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24
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Xu J, Li K, Zheng B, Dai H. Treatment and longitudinal follow-up of CNV associated with pattern dystrophy with novel PRPH2 variant. Ophthalmic Genet 2021; 42:768-772. [PMID: 34486473 DOI: 10.1080/13816810.2021.1952617] [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] [Indexed: 10/20/2022]
Abstract
BACKGROUND Peripherin-2 (PRPH2) is a transmembrane glycoprotein crucial for the morphogenesis and stabilization of the photoreceptor outer segments. Variations in PRPH2 gene are associated with vision-threatening diseases. METHODS Clinical manifestations and multimodal imaging were presented, as well as treatment history and six-year follow-up. In addition, genetic testing was performed to confirm the diagnosis. RESULTS In this report, we present an extremely rare case of choroidal neovascularization (CNV) secondary to pattern dystrophy simulating fundus flavimaculatus (PDSFF). Multimodal imaging showed typical symmetric yellow flecks in posterior pole and choroidal neovascularization requiring timely treatment. A novel nonsense variant of c.552 C > G; p.Y184X in PRPH2 gene was detected. The patient received intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment and maintained a good vision after six years. CONCLUSION We described a novel PRPH2 variant (Y184X) associated with PDSFF, its multimodal imaging, and long-term prognosis. Intravitreal anti-VEGF treatment can offer excellent visual prognosis in patients with PDSFF-associated CNV.
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Affiliation(s)
- Jingjing Xu
- School of Medicine, Tsinghua University, Beijing, China
| | - Kang Li
- Department of Ophthalmology, Beijing Hospital, Beijing, China
| | - Bodi Zheng
- Department of Ophthalmology, Beijing Hospital, Beijing, China
| | - Hong Dai
- Department of Ophthalmology, Beijing Hospital, Beijing, China
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25
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Peeters MHCA, Khan M, Rooijakkers AAMB, Mulders T, Haer-Wigman L, Boon CJF, Klaver CCW, van den Born LI, Hoyng CB, Cremers FPM, den Hollander AI, Dhaenens CM, Collin RWJ. PRPH2 mutation update: In silico assessment of 245 reported and 7 novel variants in patients with retinal disease. Hum Mutat 2021; 42:1521-1547. [PMID: 34411390 PMCID: PMC9290825 DOI: 10.1002/humu.24275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/22/2021] [Accepted: 08/16/2021] [Indexed: 01/31/2023]
Abstract
Mutations in PRPH2, encoding peripherin-2, are associated with the development of a wide variety of inherited retinal diseases (IRDs). To determine the causality of the many PRPH2 variants that have been discovered over the last decades, we surveyed all published PRPH2 variants up to July 2020, describing 720 index patients that in total carried 245 unique variants. In addition, we identified seven novel PRPH2 variants in eight additional index patients. The pathogenicity of all variants was determined using the ACMG guidelines. With this, 107 variants were classified as pathogenic, 92 as likely pathogenic, one as benign, and two as likely benign. The remaining 50 variants were classified as variants of uncertain significance. Interestingly, of the total 252 PRPH2 variants, more than half (n = 137) were missense variants. All variants were uploaded into the Leiden Open source Variation and ClinVar databases. Our study underscores the need for experimental assays for variants of unknown significance to improve pathogenicity classification, which would allow us to better understand genotype-phenotype correlations, and in the long-term, hopefully also support the development of therapeutic strategies for patients with PRPH2-associated IRD.
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Affiliation(s)
- Manon H C A Peeters
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | | | - Timo Mulders
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, Amsterdam, The Netherlands
| | - Caroline C W Klaver
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Ophthalmology, Erasmus University Medical Centre, Rotterdam, The Netherlands.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - L Ingeborgh van den Born
- The Rotterdam Eye Hospital, Rotterdam, The Netherlands.,Rotterdam Ophthalmic Institute, Rotterdam, The Netherlands
| | - Carel B Hoyng
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Claire-Marie Dhaenens
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Biochemistry and Molecular Biology, Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, Lille, France
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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26
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Li WN, Du XJ, Zhang YT, Wang LY, Zhu J. A novel mutation in the PRPH2 gene in a Chinese pedigree with retinitis pigmentosa and angle-closure glaucoma. BMC Ophthalmol 2021; 21:302. [PMID: 34399712 PMCID: PMC8369728 DOI: 10.1186/s12886-021-02064-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 08/07/2021] [Indexed: 11/10/2022] Open
Abstract
Background Retinitis pigmentosa (RP) is a rare, progressive, and hereditary disorder that leads to the progressive loss of vision and visual field, and in some cases blindness. The specific relationship between RP and glaucoma has been debated for decades. Methods In this study, we examined a Han RP family with concomitant angle-closure glaucoma (ACG), performed an inductive analysis of their clinical features and assistant results, and applied whole-exome sequencing (WES) technology for a molecular diagnosis. Results A novel transversion mutation (c.626 T > A) was identified in the peripherin-2 (PRPH2) gene in the proband, resulting in the substitution of Valine to aspartic acid in codon 209. A full ophthalmic examination showed that the proband with the c.626 T > A mutation had a typical RP manifestation, with close angles; however, the proband’s elder brother, who lacked the novel mutation, had a normal fundus and open angles. Conclusion Our results extend the genetic mutation spectrum of PRPH2 in RP, and provide evidence to support a genetic correlation between RP and ACG.
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Affiliation(s)
- Wei-Ning Li
- Department of Ophthalmology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107#, Wenhua Xi Road, Jinan, Shandong, 250012, People's Republic of China
| | - Xiu-Juan Du
- Affiliated Eye Hospital of Shandong University of TCM, Jinan, Shandong, 250002, People's Republic of China
| | - Yu-Ting Zhang
- Department of Ophthalmology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107#, Wenhua Xi Road, Jinan, Shandong, 250012, People's Republic of China
| | - Le-Yi Wang
- Department of Ophthalmology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107#, Wenhua Xi Road, Jinan, Shandong, 250012, People's Republic of China
| | - Jing Zhu
- Department of Ophthalmology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107#, Wenhua Xi Road, Jinan, Shandong, 250012, People's Republic of China.
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Sander CL, Sears AE, Pinto AF, Choi EH, Kahremany S, Gao F, Salom D, Jin H, Pardon E, Suh S, Dong Z, Steyaert J, Saghatelian A, Skowronska-Krawczyk D, Kiser PD, Palczewski K. Nano-scale resolution of native retinal rod disk membranes reveals differences in lipid composition. J Cell Biol 2021; 220:e202101063. [PMID: 34132745 PMCID: PMC8240855 DOI: 10.1083/jcb.202101063] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023] Open
Abstract
Photoreceptors rely on distinct membrane compartments to support their specialized function. Unlike protein localization, identification of critical differences in membrane content has not yet been expanded to lipids, due to the difficulty of isolating domain-specific samples. We have overcome this by using SMA to coimmunopurify membrane proteins and their native lipids from two regions of photoreceptor ROS disks. Each sample's copurified lipids were subjected to untargeted lipidomic and fatty acid analysis. Extensive differences between center (rhodopsin) and rim (ABCA4 and PRPH2/ROM1) samples included a lower PC to PE ratio and increased LC- and VLC-PUFAs in the center relative to the rim region, which was enriched in shorter, saturated FAs. The comparatively few differences between the two rim samples likely reflect specific protein-lipid interactions. High-resolution profiling of the ROS disk lipid composition gives new insights into how intricate membrane structure and protein activity are balanced within the ROS, and provides a model for future studies of other complex cellular structures.
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Affiliation(s)
- Christopher L. Sander
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Avery E. Sears
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Antonio F.M. Pinto
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA
| | - Elliot H. Choi
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Shirin Kahremany
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Fangyuan Gao
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - David Salom
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Hui Jin
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
| | - Els Pardon
- Vlaams Instituut voor Biotechnologie–Vrije Universiteit Brussel Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Susie Suh
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Zhiqian Dong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Jan Steyaert
- Vlaams Instituut voor Biotechnologie–Vrije Universiteit Brussel Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA
| | - Dorota Skowronska-Krawczyk
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
| | - Philip D. Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
- Research Service, VA Long Beach Healthcare System, Long Beach, CA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
- Department of Chemistry, University of California, Irvine, Irvine, CA
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28
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Lewis TR, Makia MS, Castillo CM, Al-Ubaidi MR, Naash MI, Arshavsky VY. Photoreceptor Disc Enclosure Is Tightly Controlled by Peripherin-2 Oligomerization. J Neurosci 2021; 41:3588-3596. [PMID: 33707293 PMCID: PMC8055076 DOI: 10.1523/jneurosci.0041-21.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/15/2021] [Accepted: 03/05/2021] [Indexed: 11/21/2022] Open
Abstract
Mutations in the PRPH2 gene encoding the photoreceptor-specific protein PRPH2 (also known as peripherin-2 or rds) cause a broad range of autosomal dominant retinal diseases. Most of these mutations affect the structure of the light-sensitive photoreceptor outer segment, which is composed of a stack of flattened "disc" membranes surrounded by the plasma membrane. The outer segment is renewed on a daily basis in a process whereby new discs are added at the outer segment base and old discs are shed at the outer segment tip. New discs are formed as serial membrane evaginations, which eventually enclose through a complex process of membrane remodeling (completely in rods and partially in cones). As disc enclosure proceeds, PRPH2 localizes to the rims of enclosed discs where it forms oligomers which fortify the highly curved membrane structure of these rims. In this study, we analyzed the outer segment phenotypes of mice of both sexes bearing a single copy of either the C150S or the Y141C PRPH2 mutation known to prevent or increase the degree of PRPH2 oligomerization, respectively. Strikingly, both mutations increased the number of newly forming, not-yet-enclosed discs, indicating that the precision of disc enclosure is regulated by PRPH2 oligomerization. Without tightly controlled enclosure, discs occasionally over-elongate and form large membranous "whorls" instead of disc stacks. These data show that the defects in outer segment structure arising from abnormal PRPH2 oligomerization are manifested at the stage of disc enclosure.SIGNIFICANCE STATEMENT The light-sensitive photoreceptor outer segment contains a stack of flattened "disc" membranes that are surrounded, or "enclosed," by the outer segment membrane. Disc enclosure is an adaptation increasing photoreceptor light sensitivity by facilitating the diffusion of the second messenger along the outer segment axes. However, the molecular mechanisms by which photoreceptor discs enclose within the outer segment membrane remain poorly understood. We now demonstrate that oligomers of the photoreceptor-specific protein peripherin-2, or PRPH2, play an active role in this process. We further propose that defects in disc enclosure because of abnormal PRPH2 oligomerization result in major structural abnormalities of the outer segment, ultimately leading to loss of visual function and cell degeneration in PRPH2 mutant models and human patients.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
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Strayve D, Makia MS, Kakakhel M, Sakthivel H, Conley SM, Al-Ubaidi MR, Naash MI. ROM1 contributes to phenotypic heterogeneity in PRPH2-associated retinal disease. Hum Mol Genet 2020; 29:2708-2722. [PMID: 32716032 DOI: 10.1093/hmg/ddaa160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/03/2020] [Accepted: 07/16/2020] [Indexed: 11/14/2022] Open
Abstract
Peripherin 2 (PRPH2) is a retina-specific tetraspanin protein essential for the formation of rod and cone photoreceptor outer segments (OS). Patients with mutations in PRPH2 exhibit severe retinal degeneration characterized by vast inter- and intra-familial phenotypic heterogeneity. To help understand contributors to this within-mutation disease variability, we asked whether the PRPH2 binding partner rod OS membrane protein 1 (ROM1) could serve as a phenotypic modifier. We utilized knockin and transgenic mouse models to evaluate the structural, functional and biochemical effects of eliminating one allele of Rom1 (Rom1+/-) in three different Prph2 models which mimic human disease: C213Y Prph2 (Prph2C/+), K153Del Prph2 (Prph2K/+) and R172W (Prph2R172W). Reducing Rom1 in the absence of Prph2 mutations (Rom1+/-) had no effect on retinal structure or function. However, the effects of reducing Rom1 in the presence of Prph2 mutations were highly variable. Prph2K/+/Rom1+/- mice had improved rod and cone function compared with Prph2K/+ as well as amelioration of K153Del-associated defects in PRPH2/ROM1 oligomerization. In contrast, Prph2R172W/Rom1+/- animals had worsened rod and cone function and exacerbated retinal degeneration compared with Prph2R172W animals. Removing one allele of Rom1 had no effect in Prph2C/+. Combined, our findings support a role for non-pathogenic ROM1 null variants in contributing to phenotypic variability in mutant PRPH2-associated retinal degeneration. Since the effects of Rom1 reduction are variable, our data suggest that this contribution is specific to the type of Prph2 mutation.
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Affiliation(s)
- Daniel Strayve
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Haarthi Sakthivel
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.,Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.,College of Optometry, University of Houston, Houston, TX 77004, USA.,Depatment of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.,College of Optometry, University of Houston, Houston, TX 77004, USA.,Depatment of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
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30
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Narasimhan I, Murali A, Subramanian K, Ramalingam S, Parameswaran S. Autosomal dominant retinitis pigmentosa with toxic gain of function: Mechanisms and therapeutics. Eur J Ophthalmol 2020; 31:304-320. [PMID: 32962414 DOI: 10.1177/1120672120957605] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Autosomal dominant retinitis pigmentosa is a form of retinitis pigmentosa, an inherited retinal degenerative disorder characterized by progressive loss of photoreceptors eventually leading to irreversible loss of vision. Mutations in genes involved in the basic functions of the visual system give rise to this condition. These mutations can either lead to loss of function or toxic gain of function phenotypes. While autosomal dominant retinitis pigmentosa caused by loss of function can be ideally treated by gene supplementation with a single vector to address a different spectrum of mutations in a gene, the same strategy cannot be applied to toxic gain of function phenotypes. In toxic gain of function phenotypes, the mutation in the gene results in the acquisition of a new function that can interrupt the functioning of the wildtype protein by various mechanisms leading to cell toxicity, thus making a single approach impractical. This review focuses on the genes and mechanisms that cause toxic gain of function phenotypes associated with autosomal dominant retinitis pigmentosa and provide a bird's eye view on current therapeutic strategies and ongoing clinical trials.
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Affiliation(s)
- Ishwarya Narasimhan
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Aishwarya Murali
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Krishnakumar Subramanian
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Sivaprakash Ramalingam
- Genomics and Molecular Medicine Unit, Council of Scientific and Industrial Research - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Sowmya Parameswaran
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
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31
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Spencer WJ, Lewis TR, Pearring JN, Arshavsky VY. Photoreceptor Discs: Built Like Ectosomes. Trends Cell Biol 2020; 30:904-915. [PMID: 32900570 DOI: 10.1016/j.tcb.2020.08.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/05/2020] [Accepted: 08/11/2020] [Indexed: 01/22/2023]
Abstract
The light-sensitive outer segment organelle of the vertebrate photoreceptor cell is a modified cilium filled with hundreds of flattened 'disc' membranes that provide vast light-absorbing surfaces. The outer segment is constantly renewed with new discs added at its base every day. This continuous process is essential for photoreceptor viability. In this review, we describe recent breakthroughs in the understanding of disc morphogenesis, with a focus on the molecular mechanisms responsible for initiating disc formation from the ciliary membrane. We highlight the discoveries that this mechanism evolved from an innate ciliary process of releasing small extracellular vesicles, or ectosomes, and that both disc formation and ectosome release rely on the actin cytoskeleton.
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Affiliation(s)
- William J Spencer
- Albert Eye Research Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Tylor R Lewis
- Albert Eye Research Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Jillian N Pearring
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Vadim Y Arshavsky
- Albert Eye Research Institute, Duke University Medical Center, Durham, NC 27710, USA.
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32
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Lewis TR, Makia MS, Kakakhel M, Al-Ubaidi MR, Arshavsky VY, Naash MI. Photoreceptor Disc Enclosure Occurs in the Absence of Normal Peripherin-2/rds Oligomerization. Front Cell Neurosci 2020; 14:92. [PMID: 32410962 PMCID: PMC7198881 DOI: 10.3389/fncel.2020.00092] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in the peripherin-2 gene (PRPH2, also known as rds) cause a heterogeneous range of autosomal dominant retinal diseases. PRPH2 encodes a photoreceptor-specific tetraspanin protein, PRPH2, that is a main structural component of the photoreceptor outer segment. PRPH2 distributes to the rims of outer segment disc membranes as they undergo the process of disc membrane enclosure. Within these rims, PRPH2 exists in homo-oligomeric form or as a hetero-oligomer with another tetraspanin protein, ROM1. While complete loss of PRPH2 prevents photoreceptor outer segment formation, mutations affecting the state of its oligomerization, including C150S, C213Y and Y141C, produce outer segment structural defects. In this study, we addressed whether any of these mutations also affect disc enclosure. We employed recently developed methodology for ultrastructural analysis of the retina, involving tissue processing with tannic acid, to assess the status of disc enclosure in knockin mouse models bearing either one or two alleles of the C150S, C213Y and Y141C PRPH2 mutations. While varying degrees of outer segment structural abnormalities were observed in each of these mouse models, they contained both newly forming “open” discs and mature “enclosed” discs. These data demonstrate that normal PRPH2 oligomerization is not essential for photoreceptor disc enclosure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, United States
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States.,College of Optometry, University of Houston, Houston, TX, United States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, United States.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, United States
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States.,College of Optometry, University of Houston, Houston, TX, United States
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Tebbe L, Kakakhel M, Makia MS, Al-Ubaidi MR, Naash MI. The Interplay between Peripherin 2 Complex Formation and Degenerative Retinal Diseases. Cells 2020; 9:E784. [PMID: 32213850 PMCID: PMC7140794 DOI: 10.3390/cells9030784] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/11/2020] [Accepted: 03/20/2020] [Indexed: 12/17/2022] Open
Abstract
Peripherin 2 (Prph2) is a photoreceptor-specific tetraspanin protein present in the outer segment (OS) rims of rod and cone photoreceptors. It shares many common features with other tetraspanins, including a large intradiscal loop which contains several cysteines. This loop enables Prph2 to associate with itself to form homo-oligomers or with its homologue, rod outer segment membrane protein 1 (Rom1) to form hetero-tetramers and hetero-octamers. Mutations in PRPH2 cause a multitude of retinal diseases including autosomal dominant retinitis pigmentosa (RP) or cone dominant macular dystrophies. The importance of Prph2 for photoreceptor development, maintenance and function is underscored by the fact that its absence results in a failure to initialize OS formation in rods and formation of severely disorganized OS membranous structures in cones. Although the exact role of Rom1 has not been well studied, it has been concluded that it is not necessary for disc morphogenesis but is required for fine tuning OS disc size and structure. Pathogenic mutations in PRPH2 often result in complex and multifactorial phenotypes, involving not just photoreceptors, as has historically been reasoned, but also secondary effects on the retinal pigment epithelium (RPE) and retinal/choroidal vasculature. The ability of Prph2 to form complexes was identified as a key requirement for the development and maintenance of OS structure and function. Studies using mouse models of pathogenic Prph2 mutations established a connection between changes in complex formation and disease phenotypes. Although progress has been made in the development of therapeutic approaches for retinal diseases in general, the highly complex interplay of functions mediated by Prph2 and the precise regulation of these complexes made it difficult, thus far, to develop a suitable Prph2-specific therapy. Here we describe the latest results obtained in Prph2-associated research and how mouse models provided new insights into the pathogenesis of its related diseases. Furthermore, we give an overview on the current status of the development of therapeutic solutions.
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Affiliation(s)
| | | | | | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA; (L.T.); (M.K.); (M.S.M.)
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA; (L.T.); (M.K.); (M.S.M.)
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Multistep peripherin-2/rds self-assembly drives membrane curvature for outer segment disk architecture and photoreceptor viability. Proc Natl Acad Sci U S A 2020; 117:4400-4410. [PMID: 32041874 DOI: 10.1073/pnas.1912513117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Rod and cone photoreceptor outer segment (OS) structural integrity is essential for normal vision; disruptions contribute to a broad variety of retinal ciliopathies. OSs possess many hundreds of stacked membranous disks, which capture photons and scaffold the phototransduction cascade. Although the molecular basis of OS structure remains unresolved, recent studies suggest that the photoreceptor-specific tetraspanin, peripherin-2/rds (P/rds), may contribute to the highly curved rim domains at disk edges. Here, we demonstrate that tetrameric P/rds self-assembly is required for generating high-curvature membranes in cellulo, implicating the noncovalent tetramer as a minimal unit of function. P/rds activity was promoted by disulfide-mediated tetramer polymerization, which transformed localized regions of curvature into high-curvature tubules of extended lengths. Transmission electron microscopy visualization of P/rds purified from OS membranes revealed disulfide-linked tetramer chains up to 100 nm long, suggesting that chains maintain membrane curvature continuity over extended distances. We tested this idea in Xenopus laevis photoreceptors, and found that transgenic expression of nonchain-forming P/rds generated abundant high-curvature OS membranes, which were improperly but specifically organized as ectopic incisures and disk rims. These striking phenotypes demonstrate the importance of P/rds tetramer chain formation for the continuity of rim formation during disk morphogenesis. Overall, this study advances understanding of the normal structure and function of P/rds for OS architecture and biogenesis, and clarifies how pathogenic loss-of-function mutations in P/rds cause photoreceptor structural defects to trigger progressive retinal degenerations. It also introduces the possibility that other tetraspanins may generate or sense membrane curvature in support of diverse biological functions.
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35
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Zhao Q, Zhang R, Xiao Y, Niu Y, Shao F, Li Y, Peng Z. Comparative Transcriptome Profiling of the Loaches Triplophysa bleekeri and Triplophysa rosa Reveals Potential Mechanisms of Eye Degeneration. Front Genet 2020; 10:1334. [PMID: 32010191 PMCID: PMC6977438 DOI: 10.3389/fgene.2019.01334] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 12/06/2019] [Indexed: 12/30/2022] Open
Abstract
Eye degeneration is one of the most obvious characteristics of organisms restricted to subterranean habitats. In cavefish, eye degeneration has evolved independently numerous times and each process is associated with different genetic mechanisms. To gain a better understanding of these mechanisms, we compared the eyes of adult individuals of the cave loach Triplophysa rosa and surface loach Triplophysa bleekeri. Compared with the normal eyes of the surface loach, those of the cave loach were found to possess a small abnormal lens and a defective retina containing photoreceptor cells that lack outer segments. Sequencing of the transcriptomes of both species to identify differentially expressed genes (DEGs) and genes under positive selection revealed 4,802 DEGs and 50 genes under positive selection (dN/dS > 1, FDR < 0.1). For cave loaches, we identified one Gene Ontology category related to vision that was significantly enriched in downregulated genes. Specifically, we found that many of the downregulated genes, including pitx3, lim2, crx, gnat2, rx1, rho, prph2, and β|γ-crystallin are associated with lens/retinal development and maintenance. However, compared with those in the surface loach, the lower dS rates but higher dN rates of the protein-coding sequences in T. rosa indicate that changes in amino acid sequences might be involved in the adaptation and visual degeneration of cave loaches. We also found that genes associated with light perception and light-stimulated vision have evolved at higher rates (some genes dN/dS > 1 but FDR > 0.1). Collectively, the findings of this study indicate that the degradation of cavefish vision is probably associated with both gene expression and amino acid changes and provide new insights into the mechanisms underlying the degeneration of cavefish eyes.
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Affiliation(s)
- Qingyuan Zhao
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing, China
| | - Renyi Zhang
- School of Life Sciences, Guizhou Normal University, Guiyang, China
| | - Yingqi Xiao
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing, China
| | - Yabing Niu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing, China
| | - Feng Shao
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing, China
| | - Yanping Li
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing, China
| | - Zuogang Peng
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing, China
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Dong K, Xue H, Cheng J, Su J, Li D, Zhang J, Zhang H. PRPH2 Activates Hippo Signalling and Suppresses the Invasion and Anoikis Inhibition of Laryngeal Cancer. Cancer Manag Res 2019; 11:10107-10115. [PMID: 31819643 PMCID: PMC6896914 DOI: 10.2147/cmar.s222527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 11/12/2019] [Indexed: 01/08/2023] Open
Abstract
Introduction Laryngeal cancer is the most common head and neck cancer worldwide. It is urgent to identify the mechanisms underlying laryngeal cancer pathogenesis. In the present study, we investigated the biological functions of Peripherin 2 (PRPH2) in laryngeal cancer and uncovered the molecular mechanism underlying this disease. Methods Laryngeal cancer tissues were used to analyze the expression of PRPH2. In vitro transwell matrigel invasion assay and annexin V anoikis assay in laryngeal cancer cells were conducted to investigate PRPH2 related biological functions. Quantitative real-time PCR and Western blotting were performed to investigate the expression and mechanism of PRPH2 in laryngeal cancer. Results We found that the expression of PRPH2 was significantly downregulated in laryngeal cancer tissues. Overexpression of PRPH2 suppressed the invasion and anoikis inhibition of laryngeal cancer cells. Furthermore, PRPH2 overexpression increased the phosphorylation of YAP and LATS1 and decreased the activities of Rho GTPases, while PRPH2 knockdown had opposite effects. Inhibitors of the Hippo pathway abrogated PRPH2 knockdown-induced laryngeal cancer cell invasion and anoikis inhibition. Discussion These results suggested that PRPH2 suppresses laryngeal cancer cell invasion and anoikis inhibition by activating Hippo signalling. PRPH2 may serve as a potential therapeutic target for laryngeal cancer in the future.
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Affiliation(s)
- KaiFeng Dong
- Department of Ear-Nose-Throat, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei 050031, People's Republic of China
| | - HaiTao Xue
- Department of Ear-Nose-Throat, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei 050031, People's Republic of China
| | - JianGang Cheng
- Department of Ear-Nose-Throat, Shijiazhuang Ping'an Hospital, Shijiazhuang, Hebei 050021, People's Republic of China
| | - Jing Su
- Department of Ear-Nose-Throat, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei 050031, People's Republic of China
| | - Dan Li
- Department of Ear-Nose-Throat, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei 050031, People's Republic of China
| | - JiHua Zhang
- Department of Ear-Nose-Throat, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei 050031, People's Republic of China
| | - HaoLei Zhang
- Department of Ear-Nose-Throat, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei 050031, People's Republic of China
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Chakraborty D, Strayve DG, Makia MS, Conley SM, Kakahel M, Al-Ubaidi MR, Naash MI. Novel molecular mechanisms for Prph2-associated pattern dystrophy. FASEB J 2019; 34:1211-1230. [PMID: 31914632 DOI: 10.1096/fj.201901888r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/10/2019] [Accepted: 11/14/2019] [Indexed: 01/16/2023]
Abstract
Mutations in peripherin 2 (PRPH2) have been associated with retinitis pigmentosa (RP) and macular/pattern dystrophies, but the origin of this phenotypic variability is unclear. The majority of Prph2 mutations are located in the large intradiscal loop (D2), a region that contains seven cysteines involved in intra- and intermolecular disulfide bonding and protein folding. A mutation at cysteine 213, which is engaged in an intramolecular disulfide bond, leads to butterfly-shaped pattern dystrophy in humans, in sharp contrast to mutations in the adjacent cysteine at position 214 which result in RP. To help understand this unexpected phenotypic variability, we generated a knockin mouse line carrying the C213Y disease mutation. The mutant Prph2 protein lost the ability to oligomerize with rod outer segment membrane protein 1 (Rom1), but retained the ability to form homotetramers. C213Y heterozygotes had significantly decreased overall Prph2 levels as well as decreased rod and cone function. Critically, supplementation with extra wild-type Prph2 protein elicited improvements in Prph2 protein levels and rod outer segment structure, but not functional rescue in rods or cones. These findings suggest that not all interruptions of D2 loop intramolecular disulfide bonding lead to haploinsufficiency-related RP, but rather that more subtle changes can lead to mutant proteins stable enough to exert gain-of-function defects in rods and cones. This outcome highlights the difficulty in targeting Prph2-associated gain-of-function disease and suggests that elimination of the mutant protein will be a pre-requisite for any curative therapeutic strategy.
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Affiliation(s)
- Dibyendu Chakraborty
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Daniel G Strayve
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Mashal Kakahel
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
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Learning from the Fly Photoreceptor on How Synapses Integrate Gene Expression to Sustain Retina and Brain Function. Neuron 2019; 101:548-550. [PMID: 30790533 DOI: 10.1016/j.neuron.2019.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synapse dysfunction is thought to contribute to neurodegenerative diseases. In this issue of Neuron, Tsai et al. (2019) uncover how membrane phospholipid biosynthesis regulates Drosophila photoreceptor (PR) degeneration and the synaptic vesicle pool through a transcriptional-translational feedback loop from the synaptic terminal to the nucleus.
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Lu Z, Hu X, Reilly J, Jia D, Liu F, Yu S, Liu X, Xie S, Qu Z, Qin Y, Huang Y, Lv Y, Li J, Gao P, Wong F, Shu X, Tang Z, Liu M. Deletion of the transmembrane protein Prom1b in zebrafish disrupts outer-segment morphogenesis and causes photoreceptor degeneration. J Biol Chem 2019; 294:13953-13963. [PMID: 31362982 DOI: 10.1074/jbc.ra119.008618] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 07/24/2019] [Indexed: 12/14/2022] Open
Abstract
Mutations in human prominin 1 (PROM1), encoding a transmembrane glycoprotein localized mainly to plasma membrane protrusions, have been reported to cause retinitis pigmentosa, macular degeneration, and cone-rod dystrophy. Although the structural role of PROM1 in outer-segment (OS) morphogenesis has been demonstrated in Prom1-knockout mouse, the mechanisms underlying these complex disease phenotypes remain unclear. Here, we utilized a zebrafish model to further investigate PROM1's role in the retina. The Prom1 orthologs in zebrafish include prom1a and prom1b, and our results showed that prom1b, rather than prom1a, plays an important role in zebrafish photoreceptors. Loss of prom1b disrupted OS morphogenesis, with rods and cones exhibiting differences in impairment: cones degenerated at an early age, whereas rods remained viable but with an abnormal OS, even at 9 months postfertilization. Immunofluorescence experiments with WT zebrafish revealed that Prph2, an ortholog of the human transmembrane protein peripherin 2 and also associated with OS formation, is localized to the edge of OS and is more highly expressed in the cone OS than in the rod OS. Moreover, we found that Prom1b deletion causes mislocalization of Prph2 and disrupts its oligomerization. We conclude that the variation in Prph2 levels between cones and rods was one of the reasons for the different PROM1 mutation-induced phenotypes of these retinal structures. These findings expand our understanding of the phenotypes caused by PROM1 mutations and provide critical insights into its function.
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Affiliation(s)
- Zhaojing Lu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xuebin Hu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - James Reilly
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, Scotland, United Kingdom
| | - Danna Jia
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Fei Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shanshan Yu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xiliang Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shanglun Xie
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Zhen Qu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yayun Qin
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yuwen Huang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yuexia Lv
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jingzhen Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Pan Gao
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Fulton Wong
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27710
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, Scotland, United Kingdom
| | - Zhaohui Tang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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40
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Ma CJ, Lee W, Stong N, Zernant J, Chang S, Goldstein D, Nagasaki T, Allikmets R. Late-onset pattern macular dystrophy mimicking ABCA4 and PRPH2 disease is caused by a homozygous frameshift mutation in ROM1. Cold Spring Harb Mol Case Stud 2019; 5:mcs.a003624. [PMID: 30630813 PMCID: PMC6549556 DOI: 10.1101/mcs.a003624] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 12/27/2018] [Indexed: 12/31/2022] Open
Abstract
ROM1 (retinal outer segment membrane protein 1) is a 351-amino acid integral membrane protein on Chromosome 11q, with high structural similarity to PRPH2/RDS. Localized at the rims of photoreceptor outer segments (OSs), it is required for the maintenance of OS structure. Here, we describe a case with a phenotypic manifestation of a homozygous single-base pair deletion, c.712delC (p.Leu238Cysfs*78) in the ROM1 gene, resulting in early termination at exon 2. The variant was detected by whole-exome sequencing (WES) in a 63-yr-old Caucasian woman with late-onset pattern macular dystrophy. Notably, although the phenotype resembles those caused by pathogenic variants in ABCA4 or RDS/PRPH2, no pathogenic variants in these, or any other plausible candidate genes, were identified by WES. Clinical features include the presence of hyperautofluorescent flecks, relative sparing of the central macula, and preserved visual acuity. Reduced visual sensitivity was detected among flecked regions in the retina; however, full-field electroretinogram testing revealed no generalized cone dysfunction. The described first case of the complete loss of ROM1 protein function in the retina suggests its sufficiency for late-onset macular dystrophy. ROM1 and PRPH2 pattern macular dystrophies exhibit phenotype overlap, which may be attributable to their shared role in maintenance of the photoreceptor outer segment structure.
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Affiliation(s)
- Chu Jian Ma
- Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Winston Lee
- Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Nicholas Stong
- Institute of Genomic Medicine, Columbia University, New York, New York 10032, USA
| | - Jana Zernant
- Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Stanley Chang
- Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - David Goldstein
- Institute of Genomic Medicine, Columbia University, New York, New York 10032, USA
| | - Takayuki Nagasaki
- Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Rando Allikmets
- Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.,Department of Pathology and Cell Biology, Columbia University, New York, New York 10032, USA
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41
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Conley SM, Stuck MW, Watson JN, Zulliger R, Burnett JL, Naash MI. Prph2 initiates outer segment morphogenesis but maturation requires Prph2/Rom1 oligomerization. Hum Mol Genet 2019; 28:459-475. [PMID: 30307502 PMCID: PMC6337695 DOI: 10.1093/hmg/ddy359] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/05/2018] [Indexed: 12/15/2022] Open
Abstract
The retinal disease gene peripherin 2 (PRPH2) is essential for the formation of photoreceptor outer segments (OSs), where it functions in oligomers with and without its homologue ROM1. However, the precise role of these proteins in OS morphogenesis is not understood. By utilizing a knock-in mouse expressing a chimeric protein comprised of the body of Rom1 and the C-terminus of Prph2 (termed RRCT), we find that the Prph2 C-terminus is necessary and sufficient for the initiation of OSs, while OS maturation requires the body of Prph2 and associated large oligomers. Importantly, dominant-negative physiological and biochemical defects in RRCT heterozygous rods are rescued by removing Rom1, suggesting Rom1 is a regulator for OS formation. Our experiments evaluating Prph2 trafficking show that Rom1 is a key determinant of whether Prph2 complexes utilize conventional versus unconventional (Golgi bypass) secretory pathways to reach the OS. These findings significantly advance our understanding of the molecular underpinnings of OS morphogenesis and particularly the role of Rom1.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael W Stuck
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jamie N Watson
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Rahel Zulliger
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Justin L Burnett
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA,To whom correspondence should be addressed at: Department of Biomedical Engineering University of Houston, 3517 Cullen Blvd., Room 2011, Houston, TX 77204-5060, USA. Tel: +713 7431651; E-mail:
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42
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Conley SM, Al-Ubaidi MR, Naash MI. The Role of the Prph2 C-Terminus in Outer Segment Morphogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:495-499. [PMID: 31884660 DOI: 10.1007/978-3-030-27378-1_81] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Peripherin 2 (also known as RDS/Prph2) is localized to the rims of rod and cone outer segment (OS) discs. The C-terminus of Prph2 is a critical functional domain, but its exact role is still unknown. In this mini review, we describe work on the Prph2 C-terminus, highlighting its role as a regulator of protein trafficking, membrane curvature, ectosome secretion, and membrane fusion. Evidence supports a role for the Prph2 C-terminus in these processes and demonstrates that it is necessary for the initiation of OS morphogenesis.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA.
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