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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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Williams BN, Draper A, Lang PF, Lewis TR, Smith AL, Mayerl SJ, Rougié M, Simon JM, Arshavsky VY, Greenwald SH, Gamm DM, Pinilla I, Philpot BD. Heterogeneity in the progression of retinal pathologies in mice harboring patient mimicking Impg2 mutations. Hum Mol Genet 2024; 33:448-464. [PMID: 37975905 PMCID: PMC10877459 DOI: 10.1093/hmg/ddad199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023] Open
Abstract
Biallelic mutations in interphotoreceptor matrix proteoglycan 2 (IMPG2) in humans cause retinitis pigmentosa (RP) with early macular involvement, albeit the disease progression varies widely due to genetic heterogeneity and IMPG2 mutation type. There are currently no treatments for IMPG2-RP. To aid preclinical studies toward eventual treatments, there is a need to better understand the progression of disease pathology in appropriate animal models. Toward this goal, we developed mouse models with patient mimicking homozygous frameshift (T807Ter) or missense (Y250C) Impg2 mutations, as well as mice with a homozygous frameshift mutation (Q244Ter) designed to completely prevent IMPG2 protein expression, and characterized the trajectory of their retinal pathologies across postnatal development until late adulthood. We found that the Impg2T807Ter/T807Ter and Impg2Q244Ter/Q244Ter mice exhibited early onset gliosis, impaired photoreceptor outer segment maintenance, appearance of subretinal deposits near the optic disc, disruption of the outer retina, and neurosensorial detachment, whereas the Impg2Y250C/Y250C mice exhibited minimal retinal pathology. These results demonstrate the importance of mutation type in disease progression in IMPG2-RP and provide a toolkit and preclinical data for advancing therapeutic approaches.
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Affiliation(s)
- Brittany N Williams
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Adam Draper
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Patrick F Lang
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Tylor R Lewis
- Department of Ophthalmology, Duke University, Durham, NC 27705, United States
| | - Audrey L Smith
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Steven J Mayerl
- Department of Ophthalmology and Visual Sciences, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, United States
| | - Marie Rougié
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Jeremy M Simon
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University, Durham, NC 27705, United States
| | | | - David M Gamm
- Department of Ophthalmology and Visual Sciences, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, United States
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza 50009, Spain
- Aragón Health Research Institute (IIS Aragón), Zaragoza 50009, Spain
- Department of Surgery, University of Zaragoza, Zaragoza 50009, Spain
| | - Benjamin D Philpot
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, United States
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Birtel J, Caswell R, De Silva SR, Herrmann P, Rehman S, Lotery AJ, Mahroo OA, Michaelides M, Webster AR, MacLaren RE, Charbel Issa P. IMPG2-Related Maculopathy. Am J Ophthalmol 2024; 258:32-42. [PMID: 37806544 DOI: 10.1016/j.ajo.2023.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 10/01/2023] [Accepted: 10/01/2023] [Indexed: 10/10/2023]
Abstract
PURPOSE To investigate the phenotype, variability, and penetrance of IMPG2-related maculopathy. DESIGN Retrospective observational case series. METHODS Clinical evaluation, multimodal retinal imaging, genetic testing, and molecular modeling. RESULTS A total of 25 individuals with a mono-allelic IMPG2 variant were included, 5 of whom were relatives of patients with IMPG2-associated retinitis pigmentosa. A distinct maculopathy was present in 17 individuals (median age, 52 years; range, 20-72 years), and included foveal elevation with or without subretinal vitelliform material or focal atrophy of the retinal pigment epithelium. Best-corrected visual acuity (BCVA) was ≥20/50 in the better eye (n = 15), and 5 patients were asymptomatic. Longitudinal observation (n = 8, up to 19 years) demonstrated stable maculopathy (n = 3), partial/complete resorption (n = 4) or increase (n = 1) of the subretinal material, with overall stable vision (n = 6). No manifest maculopathy was observed in 8 individuals (median age, 58 years; range, 43-83 years; BCVA ≥20/25), all were identified through segregation analysis. All 8 individuals were asymptomatic, with minimal foveal changes observed on optical coherence tomography in 3 cases. A total of 18 different variants were detected, 11 of them truncating. Molecular modeling of 5 missense variants [c.727G>C, c.1124C>A, c.2816T>A, c.3047T>C, and c.3193G>A] supported the hypothesis that these have a loss-of-function effect. CONCLUSIONS Mono-allelic IMPG2 variants may result in haploinsufficiency manifesting as a maculopathy with variable penetrance and expressivity. Family members of patients with IMPG2-related retinitis pigmentosa may present with vitelliform lesions. The maculopathy often remains limited to the fovea and is usually associated with moderate visual impairment.
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Affiliation(s)
- Johannes Birtel
- From the Oxford Eye Hospital (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom; Nuffield Laboratory of Ophthalmology (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Department of Ophthalmology (J.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Department of Ophthalmology (J.B., P.H.), University of Bonn, Bonn, Germany
| | - Richard Caswell
- Exeter Genomics Laboratory (R.C.), Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom
| | - Samantha R De Silva
- From the Oxford Eye Hospital (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom; Nuffield Laboratory of Ophthalmology (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (S.R.D.S., O.A.M., M.M., A.R.W.), London, United Kingdom; UCL Institute of Ophthalmology (S.R.D.S., O.A.M., M.M., A.R.W.), University College London, London, United Kingdom
| | - Philipp Herrmann
- Department of Ophthalmology (J.B., P.H.), University of Bonn, Bonn, Germany
| | - Salwah Rehman
- From the Oxford Eye Hospital (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom; Nuffield Laboratory of Ophthalmology (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Andrew J Lotery
- Clinical Neurosciences (A.J.L.), Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom; Southampton Eye Unit (A.J.L.), University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Omar A Mahroo
- Moorfields Eye Hospital NHS Foundation Trust (S.R.D.S., O.A.M., M.M., A.R.W.), London, United Kingdom; UCL Institute of Ophthalmology (S.R.D.S., O.A.M., M.M., A.R.W.), University College London, London, United Kingdom
| | - Michel Michaelides
- Moorfields Eye Hospital NHS Foundation Trust (S.R.D.S., O.A.M., M.M., A.R.W.), London, United Kingdom; UCL Institute of Ophthalmology (S.R.D.S., O.A.M., M.M., A.R.W.), University College London, London, United Kingdom
| | - Andrew R Webster
- Moorfields Eye Hospital NHS Foundation Trust (S.R.D.S., O.A.M., M.M., A.R.W.), London, United Kingdom; UCL Institute of Ophthalmology (S.R.D.S., O.A.M., M.M., A.R.W.), University College London, London, United Kingdom
| | - Robert E MacLaren
- From the Oxford Eye Hospital (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom; Nuffield Laboratory of Ophthalmology (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Peter Charbel Issa
- From the Oxford Eye Hospital (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom; Nuffield Laboratory of Ophthalmology (J.B., S.R.D.S., S.R., R.E.M., P.C.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
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Engfer ZJ, Lewandowski D, Dong Z, Palczewska G, Zhang J, Kordecka K, Płaczkiewicz J, Panas D, Foik AT, Tabaka M, Palczewski K. Distinct mouse models of Stargardt disease display differences in pharmacological targeting of ceramides and inflammatory responses. Proc Natl Acad Sci U S A 2023; 120:e2314698120. [PMID: 38064509 PMCID: PMC10723050 DOI: 10.1073/pnas.2314698120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/25/2023] [Indexed: 12/17/2023] Open
Abstract
Mutations in many visual cycle enzymes in photoreceptors and retinal pigment epithelium (RPE) cells can lead to the chronic accumulation of toxic retinoid byproducts, which poison photoreceptors and the underlying RPE if left unchecked. Without a functional ATP-binding cassette, sub-family A, member 4 (ABCA4), there is an elevation of all-trans-retinal and prolonged buildup of all-trans-retinal adducts, resulting in a retinal degenerative disease known as Stargardt-1 disease. Even in this monogenic disorder, there is significant heterogeneity in the time to onset of symptoms among patients. Using a combination of molecular techniques, we studied Abca4 knockout (simulating human noncoding disease variants) and Abca4 knock-in mice (simulating human misfolded, catalytically inactive protein variants), which serve as models for Stargardt-1 disease. We compared the two strains to ascertain whether they exhibit differential responses to agents that affect cytokine signaling and/or ceramide metabolism, as alterations in either of these pathways can exacerbate retinal degenerative phenotypes. We found different degrees of responsiveness to maraviroc, a known immunomodulatory CCR5 antagonist, and to the ceramide-lowering agent AdipoRon, an agonist of the ADIPOR1 and ADIPOR2 receptors. The two strains also display different degrees of transcriptional deviation from matched WT controls. Our phenotypic comparison of the two distinct Abca4 mutant-mouse models sheds light on potential therapeutic avenues previously unexplored in the treatment of Stargardt disease and provides a surrogate assay for assessing the effectiveness for genome editing.
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Affiliation(s)
- Zachary J. Engfer
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
- Department of Physiology and Biophysics, University of California, Irvine, CA92697
| | - Dominik Lewandowski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Zhiqian Dong
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Grazyna Palczewska
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Jianye Zhang
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Katarzyna Kordecka
- Ophthalmic Biology Group, International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Jagoda Płaczkiewicz
- Ophthalmic Biology Group, International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Damian Panas
- International Centre for Translational Eye Research, Warsaw01-224, Poland
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Andrzej T. Foik
- Ophthalmic Biology Group, International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Marcin Tabaka
- International Centre for Translational Eye Research, Warsaw01-224, Poland
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
- Department of Physiology and Biophysics, University of California, Irvine, CA92697
- Department of Chemistry, University of California, Irvine, CA92697
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA92697
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Wen S, Wang M, Qian X, Li Y, Wang K, Choi J, Pennesi ME, Yang P, Marra M, Koenekoop RK, Lopez I, Matynia A, Gorin M, Sui R, Yao F, Goetz K, Porto FBO, Chen R. Systematic assessment of the contribution of structural variants to inherited retinal diseases. Hum Mol Genet 2023; 32:2005-2015. [PMID: 36811936 PMCID: PMC10244226 DOI: 10.1093/hmg/ddad032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/03/2023] [Accepted: 02/11/2023] [Indexed: 02/24/2023] Open
Abstract
Despite increasing success in determining genetic diagnosis for patients with inherited retinal diseases (IRDs), mutations in about 30% of the IRD cases remain unclear or unsettled after targeted gene panel or whole exome sequencing. In this study, we aimed to investigate the contributions of structural variants (SVs) to settling the molecular diagnosis of IRD with whole-genome sequencing (WGS). A cohort of 755 IRD patients whose pathogenic mutations remain undefined were subjected to WGS. Four SV calling algorithms including include MANTA, DELLY, LUMPY and CNVnator were used to detect SVs throughout the genome. All SVs identified by any one of these four algorithms were included for further analysis. AnnotSV was used to annotate these SVs. SVs that overlap with known IRD-associated genes were examined with sequencing coverage, junction reads and discordant read pairs. Polymerase Chain Reaction (PCR) followed by Sanger sequencing was used to further confirm the SVs and identify the breakpoints. Segregation of the candidate pathogenic alleles with the disease was performed when possible. A total of 16 candidate pathogenic SVs were identified in 16 families, including deletions and inversions, representing 2.1% of patients with previously unsolved IRDs. Autosomal dominant, autosomal recessive and X-linked inheritance of disease-causing SVs were observed in 12 different genes. Among these, SVs in CLN3, EYS and PRPF31 were found in multiple families. Our study suggests that the contribution of SVs detected by short-read WGS is about 0.25% of our IRD patient cohort and is significantly lower than that of single nucleotide changes and small insertions and deletions.
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Affiliation(s)
- Shu Wen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Meng Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xinye Qian
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yumei Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Keqing Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jongsu Choi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mark E Pennesi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Paul Yang
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Molly Marra
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Robert K Koenekoop
- McGill Ocular Genetics Laboratory and Centre, Department of Paediatric Surgery, Human Genetics, and Ophthalmology, McGill University Health Centre, Montreal, Quebec, H4A 3S5, Canada
| | - Irma Lopez
- McGill Ocular Genetics Laboratory and Centre, Department of Paediatric Surgery, Human Genetics, and Ophthalmology, McGill University Health Centre, Montreal, Quebec, H4A 3S5, Canada
| | - Anna Matynia
- Jules Stein Eye Institute, Los Angeles, CA 90095, USA
- Ophthalmology, University of California Los Angeles David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Michael Gorin
- Jules Stein Eye Institute, Los Angeles, CA 90095, USA
- Ophthalmology, University of California Los Angeles David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Ruifang Sui
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100005, China
| | - Fengxia Yao
- Medical Research Center, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100005, China
| | - Kerry Goetz
- Office of the Director, National Eye Institute/National Institutes of Health, Bethesda, MD 20892, USA
| | - Fernanda Belga Ottoni Porto
- INRET Clínica e Centro de Pesquisa, Belo Horizonte, Minas Gerais, 30150270, Brazil
- Department of Ophthalmology, Santa Casa de Misericórdia de Belo Horizonte, Belo Horizonte, Minas Gerais, 30150221, Brazil
- Centro Oftalmológico de Minas Gerais, Belo Horizonte, Minas Gerais, 30180070, Brazil
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
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6
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Sharkova M, Chow E, Erickson T, Hocking JC. The morphological and functional diversity of apical microvilli. J Anat 2023; 242:327-353. [PMID: 36281951 PMCID: PMC9919547 DOI: 10.1111/joa.13781] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022] Open
Abstract
Sensory neurons use specialized apical processes to perceive external stimuli and monitor internal body conditions. The apical apparatus can include cilia, microvilli, or both, and is adapted for the functions of the particular cell type. Photoreceptors detect light through a large, modified cilium (outer segment), that is supported by a surrounding ring of microvilli-like calyceal processes (CPs). Although first reported 150 years ago, CPs remain poorly understood. As a basis for future study, we therefore conducted a review of existing literature about sensory cell microvilli, which can act either as the primary sensory detector or as support for a cilia-based detector. While all microvilli are finger-like cellular protrusions with an actin core, the processes vary across cell types in size, number, arrangement, dynamics, and function. We summarize the current state of knowledge about CPs and the characteristics of the microvilli found on inner ear hair cells (stereocilia) and cerebral spinal fluid-contacting neurons, with comparisons to the brush border of the intestinal and renal epithelia. The structure, stability, and dynamics of the actin core are regulated by a complement of actin-binding proteins, which includes both common components and unique features when compared across cell types. Further, microvilli are often supported by lateral links, a glycocalyx, and a defined extracellular matrix, each adapted to the function and environment of the cell. Our comparison of microvillar features will inform further research into how CPs support photoreceptor function, and also provide a general basis for investigations into the structure and functions of apical microvilli found on sensory neurons.
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Affiliation(s)
- Maria Sharkova
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Erica Chow
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Timothy Erickson
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Jennifer C Hocking
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Division of Anatomy, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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7
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Wen S, Wang M, Qian X, Li Y, Wang K, Choi J, Pennesi ME, Yang P, Marra M, Koenekoop RK, Lopez I, Matynia A, Gorin M, Sui R, Yao F, Goetz K, Porto FBO, Chen R. Systematic assessment of the contribution of structural variants to inherited retinal diseases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.02.522522. [PMID: 36789417 PMCID: PMC9928032 DOI: 10.1101/2023.01.02.522522] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite increasing success in determining genetic diagnosis for patients with inherited retinal diseases (IRDs), mutations in about 30% of the IRD cases remain unclear or unsettled after targeted gene panel or whole exome sequencing. In this study, we aimed to investigate the contributions of structural variants (SVs) to settling the molecular diagnosis of IRD with whole-genome sequencing (WGS). A cohort of 755 IRD patients whose pathogenic mutations remain undefined was subjected to WGS. Four SV calling algorithms including include MANTA, DELLY, LUMPY, and CNVnator were used to detect SVs throughout the genome. All SVs identified by any one of these four algorithms were included for further analysis. AnnotSV was used to annotate these SVs. SVs that overlap with known IRD-associated genes were examined with sequencing coverage, junction reads, and discordant read pairs. PCR followed by Sanger sequencing was used to further confirm the SVs and identify the breakpoints. Segregation of the candidate pathogenic alleles with the disease was performed when possible. In total, sixteen candidate pathogenic SVs were identified in sixteen families, including deletions and inversions, representing 2.1% of patients with previously unsolved IRDs. Autosomal dominant, autosomal recessive, and X-linked inheritance of disease-causing SVs were observed in 12 different genes. Among these, SVs in CLN3, EYS, PRPF31 were found in multiple families. Our study suggests that the contribution of SVs detected by short-read WGS is about 0.25% of our IRD patient cohort and is significantly lower than that of single nucleotide changes and small insertions and deletions.
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8
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Serjanov D, Hyde DR. Extracellular Matrix: The Unexplored Aspects of Retinal Pathologies and Regeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:309-317. [PMID: 37440050 DOI: 10.1007/978-3-031-27681-1_45] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Nearly a billion people worldwide are affected by vision-impairing conditions, with retinal degenerative diseases being a major cause of blindness. Unfortunately, such diseases are often permanent and progressive, resulting in further degeneration and loss of sight, due to the human retina possessing little, if any, regenerative capacity. Despite numerous efforts and great progress being made to understand the molecular mechanisms of these diseases and possible therapies, the majority of investigations focused on cell-intrinsic factors. However, the microenvironment surrounding retinal cells throughout these processes also plays an important role, though our current understanding of its involvement remains limited. Here we present a brief overview of the current state of the field of extracellular matrix studies within the retina and its potential roles in retinal diseases and potential therapeutic approaches.
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Affiliation(s)
- Dmitri Serjanov
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - David R Hyde
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
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9
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Mayerl SJ, Bajgai S, Ludwig AL, Jager LD, Williams BN, Bacig C, Stoddard C, Sinha D, Philpot BD, Gamm DM. Human retinal organoids harboring IMPG2 mutations exhibit a photoreceptor outer segment phenotype that models advanced retinitis pigmentosa. Stem Cell Reports 2022; 17:2409-2420. [PMID: 36206764 PMCID: PMC9669399 DOI: 10.1016/j.stemcr.2022.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 11/05/2022] Open
Abstract
Interphotoreceptor matrix proteoglycan 2 (IMPG2) mutations cause a severe form of early-onset retinitis pigmentosa (RP) with macular involvement. IMPG2 is expressed by photoreceptors and incorporated into the matrix that surrounds the inner and outer segments (OS) of rods and cones, but the mechanism of IMPG2-RP remains unclear. Loss of Impg2 function in mice produces a mild, late-onset photoreceptor phenotype without the characteristic OS loss that occurs in human patients. We generated retinal organoids (ROs) from patient-derived induced pluripotent stem (iPS) cells and gene-edited embryonic stem cells to model human IMPG2-RP in vitro. All ROs harboring IMPG2 mutations lacked an OS layer, in contrast to isogenic controls. Subsequent protein analyses revealed that this phenotype arises due to a loss of IMPG2 expression or its inability to undergo normal post-translational modifications. We hypothesized that loss of IMPG2 function destabilizes the interphotoreceptor matrix and renders the OS vulnerable to physical stressors, which is accentuated in the tissue culture environment. In support of this mechanism, transplantation of IMPG2 mutant ROs into the protected subretinal space of immunocompromised rodents restored OS production. Beyond providing a robust platform to study IMPG2-RP, this human RO model system may serve a broader role in honing strategies to treat advanced photoreceptor-based diseases.
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Affiliation(s)
- Steven J Mayerl
- Cellular and Molecular Pathology University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Simona Bajgai
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Allison L Ludwig
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI, USA; Comparative Biomedical Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Lindsey D Jager
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Brittany N Williams
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, USA
| | - Cole Bacig
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Christopher Stoddard
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Divya Sinha
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Benjamin D Philpot
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, USA
| | - David M Gamm
- Cellular and Molecular Pathology University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA.
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10
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Mitchell B, Coulter C, Geldenhuys WJ, Rhodes S, Salido EM. Interphotoreceptor matrix proteoglycans IMPG1 and IMPG2 proteolyze in the SEA domain and reveal localization mutual dependency. Sci Rep 2022; 12:15535. [PMID: 36109576 PMCID: PMC9478142 DOI: 10.1038/s41598-022-19910-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/06/2022] [Indexed: 11/08/2022] Open
Abstract
The interphotoreceptor matrix (IPM) is a specialized extracellular mesh of molecules surrounding the inner and outer segments of photoreceptor neurons. Interphotoreceptor matrix proteoglycan 1 and 2 (IMPG1 and IMPG2) are major components of the IPM. Both proteoglycans possess SEA (sperm protein, enterokinase and agrin) domains, which may support proteolysis. Interestingly, mutations in the SEA domains of IMPG1 and IMPG2 are associated with vision disease in humans. However, if SEA domains in IMPG molecules undergo proteolysis, and how this contributes to vision pathology is unknown. Therefore, we investigated SEA-mediated proteolysis of IMPG1 and IMPG2 and its significance to IPM physiology. Immunoblot analysis confirmed proteolysis of IMPG1 and IMPG2 in the retinas of wildtype mice. Point mutations mimicking human mutations in the SEA domain of IMPG1 that are associated with vision disease inhibited proteolysis. These findings demonstrate that proteolysis is part of the maturation of IMPG1 and IMPG2, in which deficits are associated with vision diseases. Further, immunohistochemical assays showed that proteolysis of IMPG2 generated two subunits, a membrane-attached peptide and an extracellular peptide. Notably, the extracellular portion of IMPG2 trafficked from the IPM around the inner segment toward the outer segment IPM by an IMPG1-dependent mechanism. This result provides the first evidence of a trafficking system that shuttles IMPG1 and IMPG2 from the inner to outer IPM in a co-dependent manner. In addition, these results suggest an interaction between IMPG1-IMPG2 and propose that mutations affecting one IMPG could affect the localization of the normal IMPG partner, contributing to the disease mechanism of vision diseases associated with defective IMPG molecules.
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Affiliation(s)
- Benjamin Mitchell
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, USA
| | - Chloe Coulter
- Undergraduate Program in Biochemistry, West Virginia University, Morgantown, WV, USA
| | - Werner J Geldenhuys
- Department of Neuroscience, School of Medicine, West Virginia University, Morgantown, WV, USA
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, USA
| | - Scott Rhodes
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, USA
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV, USA
| | - Ezequiel M Salido
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, USA.
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV, USA.
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11
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SPACR Encoded by IMPG1 Is Essential for Photoreceptor Survival by Interplaying between the Interphotoreceptor Matrix and the Retinal Pigment Epithelium. Genes (Basel) 2022; 13:genes13091508. [PMID: 36140676 PMCID: PMC9498744 DOI: 10.3390/genes13091508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 11/20/2022] Open
Abstract
Several pathogenic variants have been reported in the IMPG1 gene associated with the inherited retinal disorders vitelliform macular dystrophy (VMD) and retinitis pigmentosa (RP). IMPG1 and its paralog IMPG2 encode for two proteoglycans, SPACR and SPACRCAN, respectively, which are the main components of the interphotoreceptor matrix (IPM), the extracellular matrix surrounding the photoreceptor cells. To determine the role of SPACR in the pathological mechanisms leading to RP and VMD, we generated a knockout mouse model lacking Impg1, the mouse ortholog. Impg1-deficient mice show abnormal accumulation of autofluorescent deposits visible by fundus imaging and spectral-domain optical coherence tomography (SD-OCT) and attenuated electroretinogram responses from 9 months of age. Furthermore, SD-OCT of Impg1−/− mice shows a degeneration of the photoreceptor layer, and transmission electron microscopy shows a disruption of the IPM and the retinal pigment epithelial cells. The decrease in the concentration of the chromophore 11-cis-retinal supports this loss of photoreceptors. In conclusion, our results demonstrate the essential role of SPACR in maintaining photoreceptors. Impg1−/− mice provide a novel model for mechanistic investigations and the development of therapies for VMD and RP caused by IMPG1 pathogenic variants.
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12
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Retinal Proteomic Alterations and Combined Transcriptomic-Proteomic Analysis in the Early Stages of Progression of a Mouse Model of X-Linked Retinoschisis. Cells 2022; 11:cells11142150. [PMID: 35883593 PMCID: PMC9321393 DOI: 10.3390/cells11142150] [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: 03/01/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 12/04/2022] Open
Abstract
X-linked retinoschisis (XLRS) is among the most commonly inherited degenerative retinopathies. XLRS is caused by functional impairment of RS1. However, the molecular mechanisms underlying RS1 malfunction remain largely uncharacterized. Here, we performed a data-independent acquisition-mass spectrometry-based proteomic analysis in RS1-null mouse retina with different postal days (Ps), including the onset (P15) and early progression stage (P56). Gene set enrichment analysis showed that type I interferon-mediated signaling was upregulated and photoreceptor proteins responsible for detection of light stimuli were downregulated at P15. Positive regulation of Tor signaling was downregulated and nuclear transcribed mRNA catabolic process nonsense-mediated decay was upregulated at P56. Moreover, the differentially expressed proteins at P15 were enriched in metabolism of RNA and RNA destabilization. A broader subcellular localization distribution and enriched proteins in visual perception and phototransduction were evident at P56. Combined transcriptomic-proteomic analysis revealed that functional impairments, including detection of visible light, visual perception, and visual phototransduction, occurred at P21 and continued until P56. Our work provides insights into the molecular mechanisms underlying the onset and progression of an XLRS mouse model during the early stages, thus enhancing the understanding of the mechanism of XLRS.
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13
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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: 10] [Impact Index Per Article: 5.0] [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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14
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Vázquez-Domínguez I, Li CHZ, Fadaie Z, Haer-Wigman L, Cremers FPM, Garanto A, Hoyng CB, Roosing S. Identification of a Complex Allele in IMPG2 as a Cause of Adult-Onset Vitelliform Macular Dystrophy. Invest Ophthalmol Vis Sci 2022; 63:27. [PMID: 35608844 PMCID: PMC9150824 DOI: 10.1167/iovs.63.5.27] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 04/21/2022] [Indexed: 12/25/2022] Open
Abstract
Purpose Inherited retinal diseases are a group of clinically and genetically heterogeneous disorders with approximately 270 genes involved. IMPG2 is associated with adult-onset vitelliform macular dystrophy. Here, we investigated two unrelated patients with vitelliform macular dystrophy to identify the underlying genetic cause. Methods Whole-exome sequencing identified a putative causal complex allele consisting of c.3023-15T>A and c.3023G>A (p.(Gly1008Asp)) in IMPG2 in both individuals. To assess its effect, in vitro splice assays in HEK293T and further characterization in patient-derived photoreceptor precursor cells (PPCs) were conducted. Results The results of the midigene splice assays in HEK293T showed that the complex allele causes a variety of splicing defects ranging from a small deletion to (multiple-)exon skipping. This finding was further validated using patient-derived PPCs that showed a significant increase of out-of-frame transcripts lacking one or multiple exons compared to control-derived PPCs. Overall, control PPCs consistently showed low levels of aberrantly spliced IMPG2 transcripts that were highly elevated in patient-derived PPCs. These differences were even more obvious upon inhibition of nonsense-mediated decay with cycloheximide. Conclusions We report a heterozygous complex allele in IMPG2 causative for adult-onset vitelliform macular dystrophy in two unrelated individuals with mild visual loss and bilateral vitelliform lesions. The predicted causal missense mutation c.3023G>A, located in the consensus splice acceptor site, enhances the splicing effect of the upstream variant c.3023-15T>A, leading to the generation of aberrant transcripts that decrease the full-length IMPG2 levels. These results suggest a haploinsufficiency mechanism of action and highlight the complementarity of using different models to functionally assesses splicing defects.
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Affiliation(s)
- Irene Vázquez-Domínguez
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Catherina H. Z. Li
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Zeinab Fadaie
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Alejandro Garanto
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Pediatrics, Amalia Children's Hospital and Radboud Institute of Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, the Netherlands
| | - Carel B. Hoyng
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
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15
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Chen L, Wang N, Lai M, Hou F, He J, Fan X, Yao X, Wang R. Clinical and genetic investigations in Chinese families with retinitis pigmentosa. Exp Biol Med (Maywood) 2022; 247:1030-1038. [PMID: 35410501 DOI: 10.1177/15353702221085711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To describe clinical and genetic characteristics in a series of Chinese patients with non-syndromic retinitis pigmentosa, a total of 20 unrelated Chinese pedigrees with non-syndromic retinitis pigmentosa were evaluated. Complete ophthalmic examinations data including the Humphrey visual field, spectral domain-optical coherence tomography, full-field electroretinography, and fundus fluorescence were collected and analyzed. Targeted exome sequencing was utilized to investigate variations in 260 known genes of inherited retinal disease, including the 90 known causative retinitis pigmentosa genes. We initially identified the potential candidate variants in the pedigrees, then validated the variants using the Sanger sequencing and performed segregation analysis to verify that the variants constituted disease-causing mutations in these pedigrees. We detected three novel (likely) pathogenic and eight previously reported (likely) pathogenic variations in nine genes reported to be related to non-syndromic retinitis pigmentosa in nine of the pedigrees. We report clinical characteristics of Chinese patients with retinitis pigmentosa and novel mutations responsible for non-syndromic retinitis pigmentosa in Chinese pedigrees, expanding the number of gene mutations associated with this disorder and clarifying its genetic basis in the Chinese population. These data will help with rapid and efficient molecular diagnosis and the study of targeted treatment for retinitis pigmentosa in this population.
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Affiliation(s)
- Ling Chen
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Affiliated Shenzhen Eye Hospital of Jinan University, Shenzhen 518040, Guangdong, P.R. China
| | - Ningli Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab, Beijing 100005, P.R. China
| | - Mingying Lai
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Affiliated Shenzhen Eye Hospital of Jinan University, Shenzhen 518040, Guangdong, P.R. China
| | - Fei Hou
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Affiliated Shenzhen Eye Hospital of Jinan University, Shenzhen 518040, Guangdong, P.R. China
| | - Jing He
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Affiliated Shenzhen Eye Hospital of Jinan University, Shenzhen 518040, Guangdong, P.R. China
| | - Xianming Fan
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Affiliated Shenzhen Eye Hospital of Jinan University, Shenzhen 518040, Guangdong, P.R. China
| | - Xue Yao
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Affiliated Shenzhen Eye Hospital of Jinan University, Shenzhen 518040, Guangdong, P.R. China
| | - Ruijuan Wang
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Affiliated Shenzhen Eye Hospital of Jinan University, Shenzhen 518040, Guangdong, P.R. China
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16
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Chatterjee S, Gupta S, Chaudhry VN, Chaudhry P, Mukherjee A, Mutsuddi M. Whole exome sequencing identifies a novel splice-site mutation in IMPG2 gene causing Stargardt-like juvenile macular dystrophy in a north Indian family. Gene 2022; 816:146158. [PMID: 34990796 DOI: 10.1016/j.gene.2021.146158] [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: 11/22/2021] [Accepted: 12/10/2021] [Indexed: 12/01/2022]
Abstract
We report on the genetic analysis of a north Indian family affected with Stargardt-like juvenile macular dystrophy. Considering an autosomal recessive inheritance of macular dystrophy in the recruited family, whole exome sequencing was employed in two affected siblings and their mother. We have identified a novel splice-site variant NC_000003.11(NM_016247.3):c.1239 + 1G > T, co-segregating in the affected siblings, in the Interphotoreceptor Matrix Proteoglycan 2 (IMPG2) gene. The identified variant is present immediately after exon 11, and is predicted to disrupt the wild-type donor splice-site of IMPG2 transcripts. We confirmed the splice-site changes in the IMPG2 transcripts using minigene functional assay. Although a number of studies on IMPG2 have demonstrated its involvement in retinitis pigmentosa and vitelliform macular dystrophy, this is the first report of a splice-site variant in IMPG2 that is responsible for Stargardt-like juvenile macular dystrophy.
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Affiliation(s)
- Souradip Chatterjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Shashank Gupta
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | | | | | - Ashim Mukherjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Mousumi Mutsuddi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
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17
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Biswas P, Villanueva AL, Soto-Hermida A, Duncan JL, Matsui H, Borooah S, Kurmanov B, Richard G, Khan SY, Branham K, Huang B, Suk J, Bakall B, Goldberg JL, Gabriel L, Khan NW, Raghavendra PB, Zhou J, Devalaraja S, Huynh A, Alapati A, Zawaydeh Q, Weleber RG, Heckenlively JR, Hejtmancik JF, Riazuddin S, Sieving PA, Riazuddin SA, Frazer KA, Ayyagari R. Deciphering the genetic architecture and ethnographic distribution of IRD in three ethnic populations by whole genome sequence analysis. PLoS Genet 2021; 17:e1009848. [PMID: 34662339 PMCID: PMC8589175 DOI: 10.1371/journal.pgen.1009848] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 11/12/2021] [Accepted: 09/29/2021] [Indexed: 12/12/2022] Open
Abstract
Patients with inherited retinal dystrophies (IRDs) were recruited from two understudied populations: Mexico and Pakistan as well as a third well-studied population of European Americans to define the genetic architecture of IRD by performing whole-genome sequencing (WGS). Whole-genome analysis was performed on 409 individuals from 108 unrelated pedigrees with IRDs. All patients underwent an ophthalmic evaluation to establish the retinal phenotype. Although the 108 pedigrees in this study had previously been examined for mutations in known IRD genes using a wide range of methodologies including targeted gene(s) or mutation(s) screening, linkage analysis and exome sequencing, the gene mutations responsible for IRD in these 108 pedigrees were not determined. WGS was performed on these pedigrees using Illumina X10 at a minimum of 30X depth. The sequence reads were mapped against hg19 followed by variant calling using GATK. The genome variants were annotated using SnpEff, PolyPhen2, and CADD score; the structural variants (SVs) were called using GenomeSTRiP and LUMPY. We identified potential causative sequence alterations in 61 pedigrees (57%), including 39 novel and 54 reported variants in IRD genes. For 57 of these pedigrees the observed genotype was consistent with the initial clinical diagnosis, the remaining 4 had the clinical diagnosis reclassified based on our findings. In seven pedigrees (12%) we observed atypical causal variants, i.e. unexpected genotype(s), including 4 pedigrees with causal variants in more than one IRD gene within all affected family members, one pedigree with intrafamilial genetic heterogeneity (different affected family members carrying causal variants in different IRD genes), one pedigree carrying a dominant causative variant present in pseudo-recessive form due to consanguinity and one pedigree with a de-novo variant in the affected family member. Combined atypical and large structural variants contributed to about 20% of cases. Among the novel mutations, 75% were detected in Mexican and 50% found in European American pedigrees and have not been reported in any other population while only 20% were detected in Pakistani pedigrees and were not previously reported. The remaining novel IRD causative variants were listed in gnomAD but were found to be very rare and population specific. Mutations in known IRD associated genes contributed to pathology in 63% Mexican, 60% Pakistani and 45% European American pedigrees analyzed. Overall, contribution of known IRD gene variants to disease pathology in these three populations was similar to that observed in other populations worldwide. This study revealed a spectrum of mutations contributing to IRD in three populations, identified a large proportion of novel potentially causative variants that are specific to the corresponding population or not reported in gnomAD and shed light on the genetic architecture of IRD in these diverse global populations.
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Affiliation(s)
- Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
- School of Biotechnology, REVA University, Bengaluru, Karnataka, India
| | - Adda L. Villanueva
- Retina and Genomics Institute, Yucatán, México
- Laboratoire de Diagnostic Moleculaire, Hôpital Maisonneuve Rosemont, Montreal, Quebec, Canada
| | - Angel Soto-Hermida
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Jacque L. Duncan
- Ophthalmology, University of California San Francisco, San Francisco, California, United States of America
| | - Hiroko Matsui
- Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Shyamanga Borooah
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Berzhan Kurmanov
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | | | - Shahid Y. Khan
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Kari Branham
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan, United States of America
| | - Bonnie Huang
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - John Suk
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Benjamin Bakall
- Ophthalmology, University of Arizona College of Medicine Phoenix, Phoenix, Arizona, United States of America
| | - Jeffrey L. Goldberg
- Byers Eye Institute, Stanford, Palo Alto, California, United States of America
| | - Luis Gabriel
- Genetics and Ophthalmology, Genelabor, Goiânia, Brazil
| | - Naheed W. Khan
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan, United States of America
| | - Pongali B. Raghavendra
- School of Biotechnology, REVA University, Bengaluru, Karnataka, India
- School of Regenerative Medicine, Manipal University, Bengaluru, Karnataka, India
| | - Jason Zhou
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Sindhu Devalaraja
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Andrew Huynh
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Akhila Alapati
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Qais Zawaydeh
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Richard G. Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - John R. Heckenlively
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan, United States of America
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
| | - Paul A. Sieving
- National Eye Institute, Bethesda, Maryland, United States of America
- Ophthalmology & Vision Science, UC Davis Medical Center, California, United States of America
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Kelly A. Frazer
- Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, United States of America
- Department of Pediatrics, Rady Children’s Hospital, Division of Genome Information Sciences, San Diego, California, United States of America
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
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18
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Xu H, Qu C, Gan L, Sun K, Tan J, Liu X, Jiang Z, Tian W, Liu W, Zhang S, Yang Y, Jiang L, Zhu X, Zhang L. Deletion of the Impg2 gene causes the degeneration of rod and cone cells in mice. Hum Mol Genet 2021; 29:1624-1634. [PMID: 32242237 DOI: 10.1093/hmg/ddaa062] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/18/2020] [Accepted: 03/30/2020] [Indexed: 11/14/2022] Open
Abstract
Variants in interphotoreceptor matrix proteoglycans (IMPG2) have been reported in retinitis pigmentosa (RP) and vitelliform macular dystrophy (VMD) patients. However, the underlying molecular mechanisms remain elusive due to a lack of suitable disease models. We developed two independent Impg2 knockout (KO) mouse models using the CRISPR/Cas9 technique to assess the in vivo functions of Impg2 in the retina. Impg2 ablation in mice recapitulated the RP phenotypes of patients, including an attenuated electroretinogram (ERG) response and the progressive degeneration of photoreceptors. The histopathological examination of Impg2-KO mice revealed irregularly arranged rod cells and mislocalized rhodopsin protein in the inner segment at 6 months of age. In addition to the pathological changes in rod cells, cone cells were also affected in KO retinas. KO retinas exhibited progressive cone cell death and impaired cone cell elongation. Further immunoblotting analysis revealed increased levels of endoplasmic reticulum (ER) stress-related proteins, including C/EBP homologous protein (CHOP), immunoglobulin heavy-chain-binding protein (BIP) and protein disulfide isomerase (PDI), in Impg2-KO mouse retinas. Increased gliosis and apoptotic cell death were also observed in the KO retinas. As autophagy is closely associated with ER stress, we then checked whether autophagy was disturbed in Impg2-KO mouse retinas. The results showed that autophagy was impaired in KO retinas, as revealed by the increased accumulation of SQSTM1 and other proteins involved in autophagy. Our results demonstrate the essential roles of Impg2 in the retina, and this study provides novel models for mechanistic investigations and development of therapies for RP caused by IMPG2 mutations.
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Affiliation(s)
- Huijuan Xu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Chengdu Institute of Biology, Sichuan Translational Medicine Research Hospital, Chinese Academy of Sciences, Chengdu 610072, Sichuan, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Chao Qu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Li Gan
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Kuanxiang Sun
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Junkai Tan
- Xiamen Eye Center, Xiamen University, Xiamen 361005, China
| | - Xuyang Liu
- Xiamen Eye Center, Xiamen University, Xiamen 361005, China
| | - Zhilin Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Wanli Tian
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Wenjing Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Shanshan Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Yeming Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Li Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Xianjun Zhu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Chengdu Institute of Biology, Sichuan Translational Medicine Research Hospital, Chinese Academy of Sciences, Chengdu 610072, Sichuan, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China.,Research Unit for Blindness Prevention of Chinese Academy of medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, First People's Hospital of Shangqiu, Shangqiu 476000, Henan, China
| | - Lin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan, China
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19
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Olivier G, Corton M, Intartaglia D, Verbakel SK, Sergouniotis PI, Le Meur G, Dhaenens CM, Naacke H, Avila-Fernández A, Hoyng CB, Klevering J, Bocquet B, Roubertie A, Sénéchal A, Banfi S, Muller A, Hamel CL, Black GC, Conte I, Roosing S, Zanlonghi X, Ayuso C, Meunier I, Manes G. Pathogenic variants in IMPG1 cause autosomal dominant and autosomal recessive retinitis pigmentosa. J Med Genet 2021; 58:570-578. [PMID: 32817297 DOI: 10.1136/jmedgenet-2020-107150] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/09/2020] [Accepted: 06/24/2020] [Indexed: 11/04/2022]
Abstract
BACKGROUND Inherited retinal disorders are a clinically and genetically heterogeneous group of conditions and a major cause of visual impairment. Common disease subtypes include vitelliform macular dystrophy (VMD) and retinitis pigmentosa (RP). Despite the identification of over 90 genes associated with RP, conventional genetic testing fails to detect a molecular diagnosis in about one third of patients with RP. METHODS Exome sequencing was carried out for identifying the disease-causing gene in a family with autosomal dominant RP. Gene panel testing and exome sequencing were performed in 596 RP and VMD families to identified additional IMPG1 variants. In vivo analysis in the medaka fish system by knockdown assays was performed to screen IMPG1 possible pathogenic role. RESULTS Exome sequencing of a family with RP revealed a splice variant in IMPG1. Subsequently, the same variant was identified in individuals from two families with either RP or VMD. A retrospective study of patients with RP or VMD revealed eight additional families with different missense or nonsense variants in IMPG1. In addition, the clinical diagnosis of the IMPG1 retinopathy-associated variant, originally described as benign concentric annular macular dystrophy, was also revised to RP with early macular involvement. Using morpholino-mediated ablation of Impg1 and its paralog Impg2 in medaka fish, we confirmed a phenotype consistent with that observed in the families, including a decreased length of rod and cone photoreceptor outer segments. CONCLUSION This study discusses a previously unreported association between monoallelic or biallelic IMPG1 variants and RP. Notably, similar observations have been reported for IMPG2.
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Affiliation(s)
- Guillaume Olivier
- Institute for Neurosciences of Montpellier, University of Montpellier, Montpellier, France
- Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier, France
| | - Marta Corton
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM)-Center for Biomedical Network Research on Rare Diseases-(CIBERER), Madrid, Spain
| | - Daniela Intartaglia
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Telethon Institute of Genetics and Medicine, Pozzuoli (NA), and Medical Genetics, Naples, Italy
| | - Sanne K Verbakel
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Panagiotis I Sergouniotis
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Central Manchester NHS Foundation Trust, Manchester Royal Eye Hospital, Manchester, M13 9WL, UK
| | - Guylène Le Meur
- Service Ophtalmologie, CHU Nantes, Nantes Université, Nantes, France
| | - Claire-Marie Dhaenens
- University Lille-Nord de France, INSERM U837, Lille, France
- Lille Neuroscience & Cognition, LilNCog, Lille, France
| | - Hélène Naacke
- Service d'ophtalmologie, Clinique Saint Joseph, Angouleme, Nouvelle Aquitaine, France
| | - Almudena Avila-Fernández
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM)-Center for Biomedical Network Research on Rare Diseases-(CIBERER), Madrid, Spain
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen Klevering
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Béatrice Bocquet
- Institute for Neurosciences of Montpellier, University of Montpellier, Montpellier, France
- Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier, France
| | - Agathe Roubertie
- Département de Neuropédiatrie, CHU Montpellier, Hôpital Gui de Chauliac, Montpellier, Hérault, France
- Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier, Hérault, France
| | - Audrey Sénéchal
- Institute for Neurosciences of Montpellier, University of Montpellier, Montpellier, France
- Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier, France
| | - Sandro Banfi
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Telethon Institute of Genetics and Medicine, Naples, Italy
| | - Agnès Muller
- Institute for Neurosciences of Montpellier, University of Montpellier, Montpellier, France
- Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier, France
| | - Christian L Hamel
- Service d'ophtalmologie, Hôpital Gui de Chauliac, CHU Montpellier, Montpellier, France
| | - Graeme C Black
- Department of Genetic Medicine, University of Manchester, Manchester, UK
| | - Ivan Conte
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Telethon Institute of Genetics and Medicine, Pozzuoli (NA), and Medical Genetics, Naples, Italy
- Department of Biology, University of Naples Federico II, Napoli, Campania, Italy
| | - Susanne Roosing
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Xavier Zanlonghi
- Institut Ophtalmologique de l'Ouest, Eye Clinic Jules Verne, Nantes, France
| | - Carmen Ayuso
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM)-Center for Biomedical Network Research on Rare Diseases-(CIBERER), Madrid, Spain
- Department of Genetics & Genomics, Centro de Investigacion Biomedica en Red (CIBER) de Enfermedades Raras, ISCIII, Madrid, Spain
| | - Isabelle Meunier
- Institute for Neurosciences of Montpellier, University of Montpellier, Montpellier, France
- National Centre in Rare Diseases, Genetics of Sensory Diseases, CHU Montpellier, Montpellier, Languedoc-Roussillon, France
| | - Gaël Manes
- Institute for Neurosciences of Montpellier, University of Montpellier, Montpellier, France
- Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier, France
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20
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Shah SM, Schimmenti LA, Marmorstein AD, Bakri SJ. ADULT-ONSET VITELLIFORM MACULAR DYSTROPHY SECONDARY TO A NOVEL IMPG2 GENE VARIANT. Retin Cases Brief Rep 2021; 15:356-358. [PMID: 30300315 DOI: 10.1097/icb.0000000000000824] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
PURPOSE To report a case of adult-onset vitelliform macular dystrophy in a patient who was found to have a previously unreported variant of the IMPG2 gene. METHODS Case report. RESULTS A 65-year-old white woman with no significant medical or ocular history presented with a complaint of persistent wavy vision for 10 months. On funduscopic examination, bilateral vitelliform lesions of approximately 1 mm in the right eye and 0.5 mm in the left eye were evident, with no choroidal neovascularization in either eye. The patient was diagnosed with adult-onset vitelliform macular dystrophy. Genetic testing revealed a single likely pathogenic variant of the IMPG2 gene that may explain the examination findings. CONCLUSION Adult-onset vitelliform macular dystrophy is a common and relatively benign condition occurring in approximately 1 in 8,000 individuals. Although vitelliform lesions can be a manifestation of systemic diseases or be idiopathic, in a minority of patients, genetic predisposition may play a role. Mutations in four particular genes BEST1, PRPH2, IMPG1, and IMPG2 have been associated with some cases of adult-onset vitelliform macular dystrophy, with this particular gene variant of IMPG2 being previously unreported.
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Affiliation(s)
- Saumya M Shah
- Mayo Clinic School of Medicine, Rochester, Minnesota
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21
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Tonade D, Kern TS. Photoreceptor cells and RPE contribute to the development of diabetic retinopathy. Prog Retin Eye Res 2021; 83:100919. [PMID: 33188897 PMCID: PMC8113320 DOI: 10.1016/j.preteyeres.2020.100919] [Citation(s) in RCA: 88] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 10/27/2020] [Accepted: 10/31/2020] [Indexed: 12/26/2022]
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness. It has long been regarded as vascular disease, but work in the past years has shown abnormalities also in the neural retina. Unfortunately, research on the vascular and neural abnormalities have remained largely separate, instead of being integrated into a comprehensive view of DR that includes both the neural and vascular components. Recent evidence suggests that the most predominant neural cell in the retina (photoreceptors) and the adjacent retinal pigment epithelium (RPE) play an important role in the development of vascular lesions characteristic of DR. This review summarizes evidence that the outer retina is altered in diabetes, and that photoreceptors and RPE contribute to retinal vascular alterations in the early stages of the retinopathy. The possible molecular mechanisms by which cells of the outer retina might contribute to retinal vascular damage in diabetes also are discussed. Diabetes-induced alterations in the outer retina represent a novel therapeutic target to inhibit DR.
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Affiliation(s)
- Deoye Tonade
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Timothy S Kern
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA; Veterans Administration Medical Center Research Service, Cleveland, OH, USA; Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA; Veterans Administration Medical Center Research Service, Long Beach, CA, USA.
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22
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Tkatchenko TV, Tkatchenko AV. Genetic network regulating visual acuity makes limited contribution to visually guided eye emmetropization. Genomics 2021; 113:2780-2792. [PMID: 34147636 DOI: 10.1016/j.ygeno.2021.06.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/25/2021] [Accepted: 06/14/2021] [Indexed: 12/13/2022]
Abstract
During postnatal development, the eye undergoes a refinement process whereby optical defocus guides eye growth towards sharp vision in a process of emmetropization. Optical defocus activates a signaling cascade originating in the retina and propagating across the back of the eye to the sclera. Several observations suggest that visual acuity might be important for optical defocus detection and processing in the retina; however, direct experimental evidence supporting or refuting the role of visual acuity in refractive eye development is lacking. Here, we used genome-wide transcriptomics to determine the relative contribution of the retinal genetic network regulating visual acuity to the signaling cascade underlying visually guided eye emmetropization. Our results provide evidence that visual acuity is regulated at the level of molecular signaling in the retina by an extensive genetic network. The genetic network regulating visual acuity makes relatively small contribution to the signaling cascade underlying refractive eye development. This genetic network primarily affects baseline refractive eye development and this influence is primarily facilitated by the biological processes related to melatonin signaling, nitric oxide signaling, phototransduction, synaptic transmission, and dopamine signaling. We also observed that the visual-acuity-related genes associated with the development of human myopia are chiefly involved in light perception and phototransduction. Our results suggest that the visual-acuity-related genetic network primarily contributes to the signaling underlying baseline refractive eye development, whereas its impact on visually guided eye emmetropization is modest.
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Affiliation(s)
| | - Andrei V Tkatchenko
- Department of Ophthalmology, Columbia University, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, USA.
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23
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Habibi I, Falfoul Y, Tran HV, El Matri K, Chebil A, El Matri L, Schorderet DF. Different Phenotypes in Pseudodominant Inherited Retinal Dystrophies. Front Cell Dev Biol 2021; 9:625560. [PMID: 33634125 PMCID: PMC7902019 DOI: 10.3389/fcell.2021.625560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/11/2021] [Indexed: 11/29/2022] Open
Abstract
Retinal dystrophies (RD) are a group of Mendelian disorders caused by rare genetic variations leading to blindness. A pathogenic variant may manifest in both dominant or recessive mode and clinical and genetic heterogeneity makes it difficult to establish a precise diagnosis. In this study, families with autosomal dominant RD in successive generations were identified, and we aimed to determine the disease's molecular origin in these consanguineous families. Whole exome sequencing was performed in the index patient of each family. The aim was to determine whether these cases truly represented examples of dominantly inherited RD, or whether another mode of inheritance might be applicable. Six potentially pathogenic variants in four genes were identified in four families. In index patient with enhanced S-cone syndrome in F1, we identified a new digenetic combination: a heterozygous variant p.[G51A];[=] in RHO and a homozygous pathogenic variant p.[R311Q];[R311Q] in NR2E3. Helicoid subretinal fibrosis associated with recessive NR2E3 variant p.[R311Q];[R311Q] was identified in F2. A new frameshift variant c.[105delG];[105delG] in RDH12 was found in F3 with cone-rod dystrophy. In F4, the compound heterozygous variants p.[R964*];[W758*] were observed in IMPG2 with a retinitis pigmentosa (RP) phenotype. We showed that both affected parents and the offspring, were homozygous for the same variants in all four families. Our results provide evidence that in consanguineous families, autosomal recessive can be transmitted as pseudodominant inheritance in RD patients, and further extend our knowledge of pathogenic variants in RD genes.
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Affiliation(s)
- Imen Habibi
- IRO-Institute for Research in Ophthalmology, Sion, Switzerland
| | - Yosra Falfoul
- Oculogenetic Laboratory LR14SP01, Faculty of Medicine of Tunis, Hedi Rais Institute of Ophthalmology (Department B), Tunis El Manar University, Tunis, Tunisia
| | - Hoai Viet Tran
- Hôpital Ophtalmique Jules-Gonin, Unité d'oculogénétique, Lausanne, Switzerland
| | - Khaled El Matri
- Oculogenetic Laboratory LR14SP01, Faculty of Medicine of Tunis, Hedi Rais Institute of Ophthalmology (Department B), Tunis El Manar University, Tunis, Tunisia
| | - Ahmed Chebil
- Oculogenetic Laboratory LR14SP01, Faculty of Medicine of Tunis, Hedi Rais Institute of Ophthalmology (Department B), Tunis El Manar University, Tunis, Tunisia
| | - Leila El Matri
- Oculogenetic Laboratory LR14SP01, Faculty of Medicine of Tunis, Hedi Rais Institute of Ophthalmology (Department B), Tunis El Manar University, Tunis, Tunisia
| | - Daniel F Schorderet
- IRO-Institute for Research in Ophthalmology, Sion, Switzerland.,Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.,Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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24
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Hitti-Malin RJ, Burmeister LM, Ricketts SL, Lewis TW, Pettitt L, Boursnell M, Schofield EC, Sargan D, Mellersh CS. A LINE-1 insertion situated in the promoter of IMPG2 is associated with autosomal recessive progressive retinal atrophy in Lhasa Apso dogs. BMC Genet 2020; 21:100. [PMID: 32894063 PMCID: PMC7487703 DOI: 10.1186/s12863-020-00911-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 08/30/2020] [Indexed: 12/30/2022] Open
Abstract
Background Canine progressive retinal atrophies are a group of hereditary retinal degenerations in dogs characterised by depletion of photoreceptor cells in the retina, which ultimately leads to blindness. PRA in the Lhasa Apso (LA) dog has not previously been clinically characterised or described in the literature, but owners in the UK are advised to have their dog examined through the British Veterinary Association/ Kennel Club/ International Sheep Dog Society (BVA/KC/ISDS) eye scheme annually, and similar schemes that are in operation in other countries. After the exclusion of 25 previously reported canine retinal mutations in LA PRA-affected dogs, we sought to identify the genetic cause of PRA in this breed. Results Analysis of whole-exome sequencing data of three PRA-affected LA and three LA without signs of PRA did not identify any exonic or splice site variants, suggesting the causal variant was non-exonic. We subsequently undertook a genome-wide association study (GWAS), which identified a 1.3 Mb disease-associated region on canine chromosome 33, followed by whole-genome sequencing analysis that revealed a long interspersed element-1 (LINE-1) insertion upstream of the IMPG2 gene. IMPG2 has previously been implicated in human retinal disease; however, until now no canine PRAs have been associated with this gene. The identification of this PRA-associated variant has enabled the development of a DNA test for this form of PRA in the breed, here termed PRA4 to distinguish it from other forms of PRA described in other breeds. This test has been used to determine the genotypes of over 900 LA dogs. A large cohort of genotyped dogs was used to estimate the allele frequency as between 0.07–0.1 in the UK LA population. Conclusions Through the use of GWAS and subsequent sequencing of a PRA case, we have identified a LINE-1 insertion in the retinal candidate gene IMPG2 that is associated with a form of PRA in the LA dog. Validation of this variant in 447 dogs of 123 breeds determined it was private to LA dogs. We envisage that, over time, the developed DNA test will offer breeders the opportunity to avoid producing dogs affected with this form of PRA.
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Affiliation(s)
- Rebekkah J Hitti-Malin
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK. .,Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK.
| | - Louise M Burmeister
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Sally L Ricketts
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Thomas W Lewis
- The Kennel Club, London, W1J 8AB, UK.,School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Louise Pettitt
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Mike Boursnell
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Ellen C Schofield
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - David Sargan
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK
| | - Cathryn S Mellersh
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
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25
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Aardema ML, Stiassny MLJ, Alter SE. Genomic Analysis of the Only Blind Cichlid Reveals Extensive Inactivation in Eye and Pigment Formation Genes. Genome Biol Evol 2020; 12:1392-1406. [PMID: 32653909 PMCID: PMC7502198 DOI: 10.1093/gbe/evaa144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2020] [Indexed: 12/21/2022] Open
Abstract
Trait loss represents an intriguing evolutionary problem, particularly when it occurs across independent lineages. Fishes in light-poor environments often evolve “troglomorphic” traits, including reduction or loss of both pigment and eyes. Here, we investigate the genomic basis of trait loss in a blind and depigmented African cichlid, Lamprologus lethops, and explore evolutionary forces (selection and drift) that may have contributed to these losses. This species, the only known blind cichlid, is endemic to the lower Congo River. Available evidence suggests that it inhabits deep, low-light habitats. Using genome sequencing, we show that genes related to eye formation and pigmentation, as well as other traits associated with troglomorphism, accumulated inactivating mutations rapidly after speciation. A number of the genes affected in L. lethops are also implicated in troglomorphic phenotypes in Mexican cavefish (Astyanax mexicanus) and other species. Analysis of heterozygosity patterns across the genome indicates that L. lethops underwent a significant population bottleneck roughly 1 Ma, after which effective population sizes remained low. Branch-length tests on a subset of genes with inactivating mutations show little evidence of directional selection; however, low overall heterozygosity may reduce statistical power to detect such signals. Overall, genome-wide patterns suggest that accelerated genetic drift from a severe bottleneck, perhaps aided by directional selection for the loss of physiologically expensive traits, caused inactivating mutations to fix rapidly in this species.
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Affiliation(s)
- Matthew L Aardema
- Department of Biology, Montclair State University.,Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York
| | - Melanie L J Stiassny
- Department of Ichthyology, American Museum of Natural History, New York, New York
| | - S Elizabeth Alter
- Department of Ichthyology, American Museum of Natural History, New York, New York.,The Graduate Center, City University of New York.,Department of Biology, York College/The City University of New York
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26
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Narayan V, Jaiswal J, Sugur H, Sd S, Rao S, Chatterjee A, Gowda H, A A, Somanna S, Santosh V. Proteomic profiling of medulloblastoma reveals novel proteins differentially expressed within each molecular subgroup. Clin Neurol Neurosurg 2020; 196:106028. [PMID: 32580068 DOI: 10.1016/j.clineuro.2020.106028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/15/2020] [Accepted: 06/14/2020] [Indexed: 01/12/2023]
Abstract
OBJECTIVES The objective of the study was to identify novel medulloblastoma (MB) biomarkers through proteomic profiling, correlate it with the molecular subgroups of MB and assess the clinical significance. METHODS Archived paraffin embedded tumor tissue blocks from 118 MB patients, operated at our institute were retrieved. Clinical information was documented from the hospital database. Tumours were stratified into molecular subgroups using the IHC markers- β Catenin, GAB-1, YAP-1 and p53. Six fresh MB tumour tissues and two control cerebellar tissues were subjected to proteomic profiling to study differential protein expression in molecular subgroups using high resolution mass spectrometry. Prominent signalling pathways activated in each subgroup were identified using the Panther pathway software. RESULTS Non WNT/SHH group was the most common (61.1 %), followed by SHH and WNT. p53 immunopositivity did not correlate with prognosis in any subgroup. Proteomic profiling revealed several novel proteins differentially expressed between MB molecular subgroups. Signalling pathways exclusively enriched in each molecular subgroup were also identified. The top upregulated proteins were PMEL and FBN2 in the WNT subgroup, SYNGR2 in the SHH subgroup and GFAP, IMPG2 and MAGEA10 in the Non WNT/Non SHH group. We validated GFAP by immunohistochemistry on the archived samples (n = 118) and noted two types of staining pattern in MBs - reactive (stellate) astrocytes and tumour cell staining. GFAP immunopositivity in tumor cells of SHH subgroup correlated with a better prognosis. CONCLUSIONS Proteomic profile identified several novel proteins differentially regulated within the molecular subgroups that could serve as potential diagnostic /prognostic biomarkers. Notably, GFAP, which was derived from proteomics data, when validated by IHC, revealed a variable staining pattern in MB tumours. The prognostic significance of GFAP in SHH tumor patients further points at the heterogeneity of this subgroup. The study also throws light on the signaling pathways activated in MB and in turn its plausible role in the tumorigenesis.
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Affiliation(s)
- Vinayak Narayan
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India
| | - Janhvi Jaiswal
- Department of Neuropathology, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India
| | - Harsha Sugur
- Department of Neuropathology, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India
| | - Shwetha Sd
- Department of Neuropathology, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India
| | - Shilpa Rao
- Department of Neuropathology, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India
| | | | | | - Arivazhagan A
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India
| | - Sampath Somanna
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India
| | - Vani Santosh
- Department of Neuropathology, National Institute of Mental Health and Neurosciences [NIMHANS], Bangalore, India.
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27
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Proteoglycan IMPG2 Shapes the Interphotoreceptor Matrix and Modulates Vision. J Neurosci 2020; 40:4059-4072. [PMID: 32265257 DOI: 10.1523/jneurosci.2994-19.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/29/2020] [Accepted: 03/19/2020] [Indexed: 12/13/2022] Open
Abstract
Photoreceptor neurons are surrounded by an extracellular matrix, called the interphotoreceptor matrix (IPM). Activities crucial to vision occur within the IPM, including trafficking of nutrients and metabolites, retinal attachment, and interactions needed for normal outer segment phagocytosis. The IPM includes the following two unique proteoglycans: IPM proteoglycan 1 (IMPG1) and IMPG2. Patients with mutations in IMPG1/IMPG2 develop visual deficits with subretinal material accumulation, highlighting the critical role of the IPM in vision. To determine the role of these proteoglycans in retinal physiology and the pathologic mechanisms that lead to vision loss, we generated mouse models lacking IMPG1/IMPG2. In normal retina, IMPG1 and IMPG2 occupy distinct IPM compartments, represent the main source of chondroitin sulfate and are fundamental for the constitution of the cone-specific glycocalyx stained by the PNA (peanut agglutinin) lectin marker. No evident morphologic or functional deficits were found in mice lacking IMPG1. In the absence of IMPG2, IMPG1 abnormally accumulated at the subretinal space need, likely leading to the formation of subretinal lesions and reduced visual function. Interestingly, mice lacking both IMPG1 and IMPG2, regardless of sex, showed normal retinal structure and function, demonstrating that the aberrant IMPG1 distribution is the main cause of the visual alterations observed in the absence of IMPG2. In conclusion, our results show the dependence of secreted proteoglycans such as IMPG1 on the extracellular environment to properly integrate into the matrix, demonstrate the role of IMPG2 in shaping the IPM, and shed light on the potential mechanisms leading to the development of subretinal lesions and vision loss.SIGNIFICANCE STATEMENT The photoreceptors are specialized neurons that drive phototransduction in the mammalian retina. These cells are organized and surrounded by an extracellular matrix, the interphotoreceptor matrix (IPM). Mutations in IPM proteoglycans are associated with blindness in humans. Our studies show that two specific proteoglycans of the IPM, IPM proteoglycan 1 (IMPG1) and IMPG2, form a dynamic structure with distinct localization and dependency. When IMPG2 is absent, IMPG1 cannot integrate into the IPM, leading to abnormal proteoglycan accumulation and visual deficits. This work adds a new layer of understanding to IPM physiology and describes the pathologic events following deficits in proteoglycans, providing novel possibilities for visual restoration in patients with IMPG-related pathologies.
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28
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Noguera ME, Jakoncic J, Ermácora MR. High-resolution structure of intramolecularly proteolyzed human mucin-1 SEA domain. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140361. [PMID: 31923589 DOI: 10.1016/j.bbapap.2020.140361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 01/26/2023]
Abstract
SEA domains are ubiquitous in large proteins associated with highly glycosylated environments. Certain SEA domains undergo intramolecular proteolysis involving a nucleophilic attack of a serine hydroxyl group on the preceding glycine carbonyl. The mucin-1 (MUC1) SEA domain has been extensively investigated as a model of intramolecular proteolysis. Since neither a general base, a general acid, nor an oxyanion hole could be identified in MUC1 SEA, it has been suggested that proteolysis is accelerated by a non-planarity of the scissile peptide bond imposed by protein folding. A reactant distorted peptide bond has been also invoked to explain the autoproteolysis of several unrelated proteins. However, the only evidence of peptide distortion in MUC1 SEA stems from molecular dynamic simulations of the reactant modeled upon a single NMR structure of the cleaved product. We report the first high-resolution X-ray structure of cleaved MUC1 SEA. Structural comparison with uncleaved SEA domains suggests that the number of residues evolutionarily inserted in the cleaved loop of MUC1 SEA precludes the formation of a properly hydrogen-bonded beta turn. By sequence analysis, we show that this conformational frustration is shared by all known cleaved SEA domains. In addition, alternative conformations of the uncleaved precursor could be modeled in which the scissile peptide bond is planar. The implications of these structures for autoproteolysis are discussed in the light of the previous research on autoproteolysis.
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Affiliation(s)
- Martín E Noguera
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Argentina; Instituto de Química y Físico-Química Biológicas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jean Jakoncic
- Photon Science Directorate, Brookhaven National Laboratory, Upton, New York, United States
| | - Mario R Ermácora
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Argentina; Grupo de Biología Estructural y Biotecnología, IMBICE, CONICET, Universidad Nacional de Quilmes,Argentina.
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29
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Datta P, Hendrickson B, Brendalen S, Ruffcorn A, Seo S. The myosin-tail homology domain of centrosomal protein 290 is essential for protein confinement between the inner and outer segments in photoreceptors. J Biol Chem 2019; 294:19119-19136. [PMID: 31694913 DOI: 10.1074/jbc.ra119.009712] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/30/2019] [Indexed: 12/13/2022] Open
Abstract
Mutations in the centrosomal protein 290 (CEP290) gene cause various ciliopathies involving retinal degeneration. CEP290 proteins localize to the ciliary transition zone and are thought to act as a gatekeeper that controls ciliary protein trafficking. However, precise roles of CEP290 in photoreceptors and pathomechanisms of retinal degeneration in CEP290-associated ciliopathies are not sufficiently understood. Using conditional Cep290 mutant mice, in which the C-terminal myosin-tail homology domain of CEP290 is disrupted after the connecting cilium is assembled, we show that this domain is essential for protein confinement between the inner and the outer segments. Upon disruption of the myosin-tail homology domain, inner segment plasma membrane proteins, including syntaxin 3 (STX3), synaptosome-associated protein 25 (SNAP25), and interphotoreceptor matrix proteoglycan 2 (IMPG2), rapidly accumulated in the outer segment. In contrast, localization of endomembrane proteins was not altered. Trafficking and confinement of most outer segment-resident proteins appeared to be unaffected or only minimally affected in Cep290 mutant mice. One notable exception was rhodopsin (RHO), which severely mislocalized to inner segments during the initial stage of degeneration. Similar mislocalization phenotypes were observed in Cep290rd16 mice. These results suggest that a failure of protein confinement at the connecting cilium and consequent accumulation of inner segment membrane proteins in the outer segment, along with insufficient RHO delivery, is part of the disease mechanisms that cause retinal degeneration in CEP290-associated ciliopathies. Our study provides insights into the pathomechanisms of retinal degenerations associated with compromised ciliary gates.
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Affiliation(s)
- Poppy Datta
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, Iowa 52242.,Institute for Vision Research, University of Iowa, Iowa City, Iowa 52242
| | - Brandon Hendrickson
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, Iowa 52242.,Institute for Vision Research, University of Iowa, Iowa City, Iowa 52242
| | - Sarah Brendalen
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, Iowa 52242.,Institute for Vision Research, University of Iowa, Iowa City, Iowa 52242
| | - Avri Ruffcorn
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, Iowa 52242.,Institute for Vision Research, University of Iowa, Iowa City, Iowa 52242
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, Iowa 52242 .,Institute for Vision Research, University of Iowa, Iowa City, Iowa 52242
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30
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Sharon D, Ben-Yosef T, Goldenberg-Cohen N, Pras E, Gradstein L, Soudry S, Mezer E, Zur D, Abbasi AH, Zeitz C, Cremers FPM, Khan MI, Levy J, Rotenstreich Y, Birk OS, Ehrenberg M, Leibu R, Newman H, Shomron N, Banin E, Perlman I. A nationwide genetic analysis of inherited retinal diseases in Israel as assessed by the Israeli inherited retinal disease consortium (IIRDC). Hum Mutat 2019; 41:140-149. [PMID: 31456290 DOI: 10.1002/humu.23903] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 01/13/2023]
Abstract
Inherited retinal diseases (IRDs) cause visual loss due to dysfunction or progressive degeneration of photoreceptors. These diseases show marked phenotypic and genetic heterogeneity. The Israeli IRD consortium (IIRDC) was established in 2013 with the goal of performing clinical and genetic mapping of the majority of Israeli IRD patients. To date, we recruited 2,420 families including 3,413 individuals with IRDs. On the basis of our estimation, these patients represent approximately 40% of Israeli IRD patients. To the best of our knowledge, this is, by far, the largest reported IRD cohort, and one of the first studies addressing the genetic analysis of IRD patients on a nationwide scale. The most common inheritance pattern in our cohort is autosomal recessive (60% of families). The most common retinal phenotype is retinitis pigmentosa (43%), followed by Stargardt disease and cone/cone-rod dystrophy. We identified the cause of disease in 56% of the families. Overall, 605 distinct mutations were identified, of which 12% represent prevalent founder mutations. The most frequently mutated genes were ABCA4, USH2A, FAM161A, CNGA3, and EYS. The results of this study have important implications for molecular diagnosis, genetic screening, and counseling, as well as for the development of new therapeutic strategies for retinal diseases.
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Affiliation(s)
- Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamar Ben-Yosef
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Nitza Goldenberg-Cohen
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Department of Ophthalmology, Bnai Zion Medical Center, Haifa, Israel.,The Krieger Eye Research Laboratory, Felsenstein Medical Research Center (FMRC), Petach Tikva, Israel
| | - Eran Pras
- Department of Ophthalmology, Assaf-Harofeh Medical Center, Zerifin, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Libe Gradstein
- Department of Ophthalmology, Soroka Medical Center and Clalit Health Services, Faculty of Health Sciences, Ben-Gurion University, Beer Sheva, Israel
| | - Shiri Soudry
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Department of Ophthalmology, Rambam Healthcare Campus, Haifa, Israel
| | - Eedy Mezer
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Department of Ophthalmology, Rambam Healthcare Campus, Haifa, Israel
| | - Dinah Zur
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Ophthalmology Division, Tel Aviv Medical Center, Tel Aviv, Israel
| | - Anan H Abbasi
- Ziv Medical Center, Safed, Israel.,The Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel
| | - Christina Zeitz
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Muhammad I Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jaime Levy
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ygal Rotenstreich
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,The Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Israel
| | - Ohad S Birk
- The Morris Kahn Laboratory of Human Genetics at the National Institute of Biotechnology in the Negev, Ben-Gurion University, Beer Sheva, Israel.,Genetics Institute, Soroka Medical Center, Faculty of Health Sciences, Ben-Gurion University, Beer Sheva, Israel
| | - Miriam Ehrenberg
- Ophthalmology Unit, Schneider Children's Medical Center in Israel, Petach Tikva, Israel
| | - Rina Leibu
- Department of Ophthalmology, Rambam Healthcare Campus, Haifa, Israel
| | - Hadas Newman
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Ophthalmology Division, Tel Aviv Medical Center, Tel Aviv, Israel
| | - Noam Shomron
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ido Perlman
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Ophthalmology Division, Tel Aviv Medical Center, Tel Aviv, Israel
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31
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Khan AO, Al Teneiji AM. Homozygous and heterozygous retinal phenotypes in families harbouring IMPG2 mutations. Ophthalmic Genet 2019; 40:247-251. [PMID: 31264916 DOI: 10.1080/13816810.2019.1627467] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Biallelic mutations in interphotoreceptor matrix proteoglycan 2 (IMPG2) have been shown to underlie recessive childhood-onset rod-cone dystrophy with early macular involvement in several families. In other families, heterozygous IMPG2 mutations have been associated with dominant vitelliform macular dystrophy. To date, the retinal phenotype of heterozygotes from families with recessive IMPG2-related retinal dystrophy has not been assessed. This study documents the genotypes and phenotypes observed in both homozygotes and available heterozygotes from additional families with IMPG2-related recessive rod-cone dystrophy. Methods: Retrospective case series (2016-2018). Results: Four families were identified. All were first-cousin marriages and had no known relation to each other. Individuals with biallelic pathogenic variants (7 individuals) had childhood-onset rod-cone dystrophy. Families 1 and 2 harboured the same novel homozygous mutation c.189dup;p.Gln64Thrfs*9 (5 individuals, 4-17 years old). Family 3 harboured the novel homozygous mutation c.533 + 4_533 + 7del;p.? (1 individual, 17 years old), and Family 4 harboured the previously reported homozygous mutation c.3262C>T;p.Arg1088* (1 individual, 45 years old). The 3 available carriers were genetically confirmed (both parents from Family 1 and the father from Family 3) and had macular focal retinal pigment epithelium thickening by optical coherence tomography (OCT). The father from Family 3 also had unilateral sectoral pigmentary retinopathy. Conclusions: Childhood-onset recessive rod-cone dystrophy with early macular involvement should prompt examination of the parents for macular focal retinal pigment epithelium thickening on OCT. If present the possibility of biallelic IMPG2 mutations in the proband should be considered. Young affected relatives of the proband can show multimodal imaging abnormalities before they are overtly symptomatic.
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Affiliation(s)
- Arif O Khan
- a Eye Institute , Cleveland Clinic Abu Dhabi , Abu Dhabi , United Arab Emirates.,b Department of Ophthalmology , Cleveland Clinic Lerner College of Medicine of Case Western University , Cleveland , Ohio , USA
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Abedin Zadeh M, Khoder M, Al-Kinani AA, Younes HM, Alany RG. Retinal cell regeneration using tissue engineered polymeric scaffolds. Drug Discov Today 2019; 24:1669-1678. [PMID: 31051266 DOI: 10.1016/j.drudis.2019.04.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/06/2019] [Accepted: 04/25/2019] [Indexed: 12/24/2022]
Abstract
Degenerative retinal diseases, such as age-related macular degeneration (AMD), can lead to permanent sight loss. Although intravitreal anti-vascular endothelial growth factor (VEGF) and steroid injections are effective for the management of early stages of wet and/or neovascular AMD (nAMD), no proven treatments currently exist for dry AMD or for the advanced geographic atrophy of the retina that follows. Tissue engineering (TE) has recently emerged as a promising alternative to repair retinal damaged and restore its functions. Here, we review recent advances in TE, with a particular emphasis on retinal regeneration. We provide an overview of retinal diseases, followed by a comprehensive review of TE techniques, cells, and polymers used in the fabrication of scaffolds for retinal cell regenerations, in particular the retinal pigment epithelium (RPE).
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Affiliation(s)
- Maria Abedin Zadeh
- Drug Discovery, Delivery and Patient Care (DDDPC) Theme, School of Life Sciences, Pharmacy and Chemistry, Kingston University London, Kingston upon Thames, London, United Kingdom; Pharmaceutics & Polymeric Drug Delivery Research Laboratory, College of Pharmacy, Qatar University, Doha, Qatar
| | - Mouhamad Khoder
- Drug Discovery, Delivery and Patient Care (DDDPC) Theme, School of Life Sciences, Pharmacy and Chemistry, Kingston University London, Kingston upon Thames, London, United Kingdom; Pharmaceutics & Polymeric Drug Delivery Research Laboratory, College of Pharmacy, Qatar University, Doha, Qatar.
| | - Ali A Al-Kinani
- Drug Discovery, Delivery and Patient Care (DDDPC) Theme, School of Life Sciences, Pharmacy and Chemistry, Kingston University London, Kingston upon Thames, London, United Kingdom; Pharmaceutics & Polymeric Drug Delivery Research Laboratory, College of Pharmacy, Qatar University, Doha, Qatar
| | - Husam M Younes
- Pharmaceutics & Polymeric Drug Delivery Research Laboratory, College of Pharmacy, Qatar University, Doha, Qatar; Office of Vice President for Research & Graduate Studies, Qatar University, Doha, Qatar
| | - Raid G Alany
- Drug Discovery, Delivery and Patient Care (DDDPC) Theme, School of Life Sciences, Pharmacy and Chemistry, Kingston University London, Kingston upon Thames, London, United Kingdom; Pharmaceutics & Polymeric Drug Delivery Research Laboratory, College of Pharmacy, Qatar University, Doha, Qatar; School of Pharmacy, The University of Auckland, Auckland, New Zealand.
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Molecular and clinical analysis of 27 German patients with Leber congenital amaurosis. PLoS One 2018; 13:e0205380. [PMID: 30576320 PMCID: PMC6303042 DOI: 10.1371/journal.pone.0205380] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/04/2018] [Indexed: 12/22/2022] Open
Abstract
Leber congenital amaurosis (LCA) is the earliest and most severe form of all inherited retinal dystrophies (IRD) and the most frequent cause of inherited blindness in children. The phenotypic overlap with other early-onset and severe IRDs as well as difficulties associated with the ophthalmic examination of infants can complicate the clinical diagnosis. To date, 25 genes have been implicated in the pathogenesis of LCA. The disorder is usually inherited in an autosomal recessive fashion, although rare dominant cases have been reported. We report the mutation spectra and frequency of genes in 27 German index patients initially diagnosed with LCA. A total of 108 LCA- and other genes implicated in IRD were analysed using a cost-effective targeted next-generation sequencing procedure based on molecular inversion probes (MIPs). Sequencing and variant filtering led to the identification of putative pathogenic variants in 25 cases, thereby leading to a detection rate of 93%. The mutation spectrum comprises 34 different alleles, 17 of which are novel. In line with previous studies, the genetic results led to a revision of the initial clinical diagnosis in a substantial proportion of cases, demonstrating the importance of genetic testing in IRD. In addition, our detection rate of 93% shows that MIPs are a cost-efficient and sensitive tool for targeted next-generation sequencing in IRD.
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Extracellular matrix component expression in human pluripotent stem cell-derived retinal organoids recapitulates retinogenesis in vivo and reveals an important role for IMPG1 and CD44 in the development of photoreceptors and interphotoreceptor matrix. Acta Biomater 2018; 74:207-221. [PMID: 29777959 DOI: 10.1016/j.actbio.2018.05.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 05/07/2018] [Accepted: 05/15/2018] [Indexed: 02/08/2023]
Abstract
The extracellular matrix (ECM) plays an important role in numerous processes including cellular proliferation, differentiation, migration, maturation, adhesion guidance and axonal growth. To date, there has been no detailed analysis of the ECM distribution during retinal ontogenesis in humans and the functional importance of many ECM components is poorly understood. In this study, the expression of key ECM components in adult mouse and monkey retina, developing and adult human retina and retinal organoids derived from human pluripotent stem cells was studied. Our data indicate that basement membrane ECMs (Fibronectin and Collagen IV) were expressed in Bruch's membrane and the inner limiting membrane of the developing human retina, whilst the hyalectins (Versican and Brevican), cluster of differentiation 44 (CD44), photoreceptor-specific ECMs Interphotoreceptor Matrix Proteoglycan 1 (IMPG1) and Interphotoreceptor Matrix Proteoglycan 2 (IMPG2) were detected in the developing interphotoreceptor matrix (IPM). The expression of IMPG1, Versican and Brevican in the developing IPM was conserved between human developing retina and human pluripotent stem cell-derived retinal organoids. Blocking the action of CD44 and IMPG1 in pluripotent stem cell derived retinal organoids affected the development of photoreceptors, their inner/outer segments and connecting cilia and disrupted IPM formation, with IMPG1 having an earlier and more significant impact. Together, our data suggest an important role for IMPG1 and CD44 in the development of photoreceptors and IPM formation during human retinogenesis. STATEMENT OF SIGNIFICANCE The expression and the role of many extracellular matrix (ECM) components during human retinal development is not fully understood. In this study, expression of key ECM components (Collagen IV, Fibronectin, Brevican, Versican, IMPG1 and IMPG2) was investigated during human retinal ontogenesis. Collagen IV and Fibronectin were expressed in Bruch's membrane; whereas Brevican, Versican, IMPG1 & IMPG2 in the developing interphotoreceptor matrix (IPM). Retinal organoids were successfully generated from pluripotent stem cells. The expression of ECM components was examined in the retinal organoids and found to recapitulate human retinal development in vivo. Using functional blocking experiments, we were able to highlight an important role for IMPG1 and CD44 in the development of photoreceptors and IPM formation.
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Carnevali A, Al-Dolat W, Sacconi R, Corbelli E, Querques L, Bandello F, Querques G. Diagnosis, management and future treatment options for adult-onset foveomacular vitelliform dystrophy. EXPERT REVIEW OF OPHTHALMOLOGY 2018. [DOI: 10.1080/17469899.2018.1483722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Adriano Carnevali
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
- Department of Ophthalmology, University of ‘Magna Graecia’, Catanzaro, Italy
| | - Wedad Al-Dolat
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Riccardo Sacconi
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
- Department of Ophthalmology, University of Verona, University hospital of Verona, Verona, Italy
| | - Eleonora Corbelli
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Lea Querques
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Giuseppe Querques
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
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Identification of Key Genes and miRNAs in Osteosarcoma Patients with Chemoresistance by Bioinformatics Analysis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4761064. [PMID: 29850522 PMCID: PMC5937522 DOI: 10.1155/2018/4761064] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/21/2018] [Accepted: 03/04/2018] [Indexed: 12/20/2022]
Abstract
Chemoresistance is a significant factor associated with poor outcomes of osteosarcoma patients. The present study aims to identify Chemoresistance-regulated gene signatures and microRNAs (miRNAs) in Gene Expression Omnibus (GEO) database. The results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) included positive regulation of transcription, DNA-templated, tryptophan metabolism, and the like. Then differentially expressed genes (DEGs) were uploaded to Search Tool for the Retrieval of Interacting Genes (STRING) to construct protein-protein interaction (PPI) networks, and 9 hub genes were screened, such as fucosyltransferase 3 (Lewis blood group) (FUT3) whose expression in chemoresistant samples was high, but with a better prognosis in osteosarcoma patients. Furthermore, the connection between DEGs and differentially expressed miRNAs (DEMs) was explored. GEO2R was utilized to screen out DEGs and DEMs. A total of 668 DEGs and 5 DEMs were extracted from GSE7437 and GSE30934 differentiating samples of poor and good chemotherapy reaction patients. The Database for Annotation, Visualization, and Integrated Discovery (DAVID) was used to perform GO and KEGG pathway enrichment analysis to identify potential pathways and functional annotations linked with osteosarcoma chemoresistance. The present study may provide a deeper understanding about regulatory genes of osteosarcoma chemoresistance and identify potential therapeutic targets for osteosarcoma.
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Verbakel SK, van Huet RAC, Boon CJF, den Hollander AI, Collin RWJ, Klaver CCW, Hoyng CB, Roepman R, Klevering BJ. Non-syndromic retinitis pigmentosa. Prog Retin Eye Res 2018; 66:157-186. [PMID: 29597005 DOI: 10.1016/j.preteyeres.2018.03.005] [Citation(s) in RCA: 522] [Impact Index Per Article: 87.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/20/2018] [Accepted: 03/22/2018] [Indexed: 12/23/2022]
Abstract
Retinitis pigmentosa (RP) encompasses a group of inherited retinal dystrophies characterized by the primary degeneration of rod and cone photoreceptors. RP is a leading cause of visual disability, with a worldwide prevalence of 1:4000. Although the majority of RP cases are non-syndromic, 20-30% of patients with RP also have an associated non-ocular condition. RP typically manifests with night blindness in adolescence, followed by concentric visual field loss, reflecting the principal dysfunction of rod photoreceptors; central vision loss occurs later in life due to cone dysfunction. Photoreceptor function measured with an electroretinogram is markedly reduced or even absent. Optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging show a progressive loss of outer retinal layers and altered lipofuscin distribution in a characteristic pattern. Over the past three decades, a vast number of disease-causing variants in more than 80 genes have been associated with non-syndromic RP. The wide heterogeneity of RP makes it challenging to describe the clinical findings and pathogenesis. In this review, we provide a comprehensive overview of the clinical characteristics of RP specific to genetically defined patient subsets. We supply a unique atlas with color fundus photographs of most RP subtypes, and we discuss the relevant considerations with respect to differential diagnoses. In addition, we discuss the genes involved in the pathogenesis of RP, as well as the retinal processes that are affected by pathogenic mutations in these genes. Finally, we review management strategies for patients with RP, including counseling, visual rehabilitation, and current and emerging therapeutic options.
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Affiliation(s)
- Sanne K Verbakel
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ramon A C van Huet
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands; Department of Ophthalmology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob W J Collin
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Caroline C W Klaver
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald Roepman
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - B Jeroen Klevering
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
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Li J, Zhang Q. Insight into the molecular genetics of myopia. Mol Vis 2017; 23:1048-1080. [PMID: 29386878 PMCID: PMC5757860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 12/29/2017] [Indexed: 11/18/2022] Open
Abstract
Myopia is the most common cause of visual impairment worldwide. Genetic and environmental factors contribute to the development of myopia. Studies on the molecular genetics of myopia are well established and have implicated the important role of genetic factors. With linkage analysis, association studies, sequencing analysis, and experimental myopia studies, many of the loci and genes associated with myopia have been identified. Thus far, there has been no systemic review of the loci and genes related to non-syndromic and syndromic myopia based on the different approaches. Such a systemic review of the molecular genetics of myopia will provide clues to identify additional plausible genes for myopia and help us to understand the molecular mechanisms underlying myopia. This paper reviews recent genetic studies on myopia, summarizes all possible reported genes and loci related to myopia, and suggests implications for future studies on the molecular genetics of myopia.
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Affiliation(s)
- Jiali Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Kelley RA, Al-Ubaidi MR, Sinha T, Genc AM, Makia MS, Ikelle L, Naash MI. Ablation of the riboflavin-binding protein retbindin reduces flavin levels and leads to progressive and dose-dependent degeneration of rods and cones. J Biol Chem 2017; 292:21023-21034. [PMID: 29079576 DOI: 10.1074/jbc.m117.785105] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 10/26/2017] [Indexed: 11/06/2022] Open
Abstract
The interface between the neural retina and the retinal pigment epithelium (RPE) is critical for several processes, including visual pigment regeneration and retinal attachment to the RPE. One of its most important functions is the exchange of metabolites between the photoreceptors and RPE because photoreceptor cells have very high energy demands, largely satisfied by oxidative metabolism. The riboflavin (RF) cofactors, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), are two key cofactors involved in oxidative metabolism. We have previously shown that retbindin is a photoreceptor-specific RF-binding protein exclusively expressed in the rods and present in the interphotoreceptor matrix at the interface between the RPE and photoreceptor outer segments. Here, we show that retbindin ablation in mice causes a retinal phenotype characterized by time- and dose-dependent declines in rod and cone photoreceptor functions as early as 120 days of age. Whereas minor retinal ultrastructural defects were observed at all ages examined, a significant decline occurred in photoreceptor nuclei at 240 days of age (∼36.8% rods and ∼19.9% cones). Interestingly, significant reductions in FAD and FMN levels were observed before the onset of degeneration (∼46.1% FAD and ∼45% FMN). These findings suggest that the reduced levels of these flavins result in the disruption of intracellular mechanisms, leading to photoreceptor cell death. Altogether, our results suggest that retbindin is a key player in the acquisition and retention of flavins in the neural retina, warranting future investigation into retbindin's role in photoreceptor cell death in models of retinal degenerative disorders.
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Affiliation(s)
- Ryan A Kelley
- From the Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Muayyad R Al-Ubaidi
- From the Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Tirthankar Sinha
- From the Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Ayse M Genc
- From the Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Mustafa S Makia
- From the Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Larissa Ikelle
- From the Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Muna I Naash
- From the Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
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Gonzalez-Fernandez F, Fornalik M, Garlipp MA, Gonzalez-Fernandez P, Sung D, Meyer A, Baier R. Pericellular interphotoreceptor matrix dictates outer retina critical surface tension. Exp Eye Res 2017; 167:163-173. [PMID: 29051013 DOI: 10.1016/j.exer.2017.10.014] [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: 01/25/2017] [Revised: 07/30/2017] [Accepted: 10/12/2017] [Indexed: 11/15/2022]
Abstract
Retinal detachments create two pathological surfaces, the surface of the outer neural retinal, and an apical retinal-pigmented epithelium (RPE) surface. The physicochemical properties of these two new surfaces are poorly understood. At a molecular level little is known how detachments form, how to optimize reattachment, or prevent extension of the detachment. A major limitation is lack of information about the biophysical consequences of the retina-RPE separation. The primary challenge is determining the molecular properties of the pathological interface surfaces. Here, using detached bovine retina, we show that this hurdle can be overcome through a combination of biophysical and ultrastructural approaches. The outer surface of freshly detached bovine neural retina, and isolated molecular components of the outer retina were subjected to: 1) Contact angle goniometry to determine the critical surface tension of the outer retinal surface, isolated insoluble interphotoreceptor matrix (IPM) and purified interphotoreceptor retinoid binding protein (IRBP); 2) Multiple attenuated internal reflectance infrared (MAIR-IR) spectroscopy was used to characterize the molecular composition of the retinal surface. MAIR-IR depth penetration was established through ellipsometric measurement of barium-stearate films. Light microscopy, immunohistochemistry and electron microscopy defined the structures probed spectroscopically. Furthermore, the data were correlated to IR spectra of docosahexaenoic acid, hyaluronan, chondroitin-6-sulfate and IRBP, and imaging by IR-microscopy. We found that the retinal critical surface tension is 24 mN/m, similar to isolated insoluble IPM and lower than IRBP. Barium-stearate calibration studies established that the MAIR-IR spectroscopy penetration depth was 0.2 μm. Ultrastructural observations and MAIR-IR studies of isolated outer retina components determined that the pericellular IPM coating the outer retinal surface is primarily responsible for these surface properties. The critical surface tension of detached bovine retina is dictated not by the outer segments, but by a pericellular IPM covering the outer segment tips.
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Affiliation(s)
- Federico Gonzalez-Fernandez
- Medical Research Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS, United States; Ophthalmology and Pathology, University of Mississippi Medical Center, Jackson, MS, United States; Ophthalmology, Ross Eye Institute, SUNY, Buffalo, NY, United States; Pathology & Anatomic Sciences, SUNY, Buffalo, NY, United States.
| | - Mark Fornalik
- Center for Biosurfaces, SUNY, Buffalo, NY, United States
| | | | - Priscilla Gonzalez-Fernandez
- Medical Research Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS, United States; Ophthalmology, Ross Eye Institute, SUNY, Buffalo, NY, United States
| | - Dongjin Sung
- Ophthalmology, Ross Eye Institute, SUNY, Buffalo, NY, United States
| | - Anne Meyer
- Ophthalmology, Ross Eye Institute, SUNY, Buffalo, NY, United States; Center for Biosurfaces, SUNY, Buffalo, NY, United States
| | - Robert Baier
- Ophthalmology, Ross Eye Institute, SUNY, Buffalo, NY, United States; Center for Biosurfaces, SUNY, Buffalo, NY, United States
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Genetic characterization and disease mechanism of retinitis pigmentosa; current scenario. 3 Biotech 2017; 7:251. [PMID: 28721681 DOI: 10.1007/s13205-017-0878-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
Retinitis pigmentosa is a group of genetically transmitted disorders affecting 1 in 3000-8000 individual people worldwide ultimately affecting the quality of life. Retinitis pigmentosa is characterized as a heterogeneous genetic disorder which leads by progressive devolution of the retina leading to a progressive visual loss. It can occur in syndromic (with Usher syndrome and Bardet-Biedl syndrome) as well as non-syndromic nature. The mode of inheritance can be X-linked, autosomal dominant or autosomal recessive manner. To date 58 genes have been reported to associate with retinitis pigmentosa most of them are either expressed in photoreceptors or the retinal pigment epithelium. This review focuses on the disease mechanisms and genetics of retinitis pigmentosa. As retinitis pigmentosa is tremendously heterogeneous disorder expressing a multiplicity of mutations; different variations in the same gene might induce different disorders. In recent years, latest technologies including whole-exome sequencing contributing effectively to uncover the hidden genesis of retinitis pigmentosa by reporting new genetic mutations. In future, these advancements will help in better understanding the genotype-phenotype correlations of disease and likely to develop new therapies.
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Brandl C, Schulz HL, Charbel Issa P, Birtel J, Bergholz R, Lange C, Dahlke C, Zobor D, Weber BHF, Stöhr H. Mutations in the Genes for Interphotoreceptor Matrix Proteoglycans, IMPG1 and IMPG2, in Patients with Vitelliform Macular Lesions. Genes (Basel) 2017. [PMID: 28644393 PMCID: PMC5541303 DOI: 10.3390/genes8070170] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A significant portion of patients diagnosed with vitelliform macular dystrophy (VMD) do not carry causative mutations in the classic VMD genes BEST1 or PRPH2. We therefore performed a mutational screen in a cohort of 106 BEST1/PRPH2-negative VMD patients in two genes encoding secreted interphotoreceptor matrix proteoglycans-1 and -2 (IMPG1 and IMPG2). We identified two novel mutations in IMPG1 in two simplex VMD cases with disease onset in their early childhood, a heterozygous p.(Leu238Pro) missense mutation and a homozygous c.807 + 5G > A splice site mutation. The latter induced partial skipping of exon 7 of IMPG1 in an in vitro splicing assay. Furthermore, we found heterozygous mutations including three stop [p.(Glu226*), p.(Ser522*), p.(Gln856*)] and five missense mutations [p.(Ala243Pro), p.(Gly1008Asp), p.(Phe1016Ser), p.(Tyr1042Cys), p.(Cys1077Phe)] in the IMPG2 gene, one of them, p.(Cys1077Phe), previously associated with VMD. Asymptomatic carriers of the p.(Ala243Pro) and p.(Cys1077Phe) mutations show subtle foveal irregularities that could characterize a subclinical stage of disease. Taken together, our results provide further evidence for an involvement of dominant and recessive mutations in IMPG1 and IMPG2 in VMD pathology. There is a remarkable similarity in the clinical appearance of mutation carriers, presenting with bilateral, central, dome-shaped foveal accumulation of yellowish material with preserved integrity of the retinal pigment epithelium (RPE). Clinical symptoms tend to be more severe for IMPG1 mutations.
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Affiliation(s)
- Caroline Brandl
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Regensburg, 93053 Regensburg, Germany;
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
- Lehrstuhl für Genetische Epidemiologie, Universität Regensburg, 93053 Regensburg, Germany
| | - Heidi L. Schulz
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
| | - Peter Charbel Issa
- Department of Ophthalmology, University of Bonn, 53113 Bonn, Germany;
- Oxford Eye Hospital, OUH NHS Foundation Trust and the Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3BD, UK
| | - Johannes Birtel
- Department of Ophthalmology, University of Bonn, 53113 Bonn, Germany;
| | - Richard Bergholz
- Klinik für Augenheilkunde, Charité—Universitätsmedizin Berlin, 10117 Berlin, Germany;
| | - Clemens Lange
- Klinik für Augenheilkunde, Universitätsklinikum Freiburg, Medizinische Fakultät, Albert Ludwigs Universität Freiburg, 79085 Freiburg, Germany;
| | - Claudia Dahlke
- Klinik für Augenheilkunde, Universitätsklinikum Köln, 50937 Köln, Germany;
| | - Ditta Zobor
- Forschungsinstitut für Augenheilkunde, Universitätsklinikum Tübingen, 72076 Tübingen, Germany;
| | - Bernhard H. F. Weber
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
| | - Heidi Stöhr
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
- Correspondence: ; Tel.: +49-941-944-5424
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Stahl BA, Gross JB. A Comparative Transcriptomic Analysis of Development in Two Astyanax Cavefish Populations. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2017; 328:515-532. [PMID: 28612405 DOI: 10.1002/jez.b.22749] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/24/2017] [Accepted: 04/11/2017] [Indexed: 12/11/2022]
Abstract
Organisms that are isolated into extreme environments often evolve extreme phenotypes. However, global patterns of dynamic gene expression changes that accompany dramatic environmental changes remain largely unknown. The blind Mexican cavefish, Astyanax mexicanus, has evolved a number of severe cave-associated phenotypes including loss of vision and pigmentation, craniofacial bone fusions, increased fat storage, reduced sleep, and amplified nonvisual sensory systems. Interestingly, surface-dwelling forms have repeatedly entered different caves throughout Mexico, providing a natural set of "replicate" instances of cave isolation. These surrogate "ancestral" surface-dwelling forms persist in nearby rivers, enabling direct comparisons to the "derived" cave-dwelling form. We evaluated changes associated with subterranean isolation by measuring differential gene expression in two geographically distinct cave-dwelling populations (Pachón and Tinaja). To understand the impact of these expression changes on development, we performed RNA-sequencing across four critical stages during which troglomorphic traits first appear in cavefish embryos. Gene ontology (GO) studies revealed similar functional profiles evolved in both independent cave lineages. However, enrichment studies indicated that similar GO profiles were occasionally mediated by different genes. Certain "master" regulators, such as Otx2 and Mitf, appear to be important loci for cave adaptation, as remarkably similar patterns of expression were identified in both independent cave lineages. This work reveals that adaptation to an extreme environment, in two distinct cavefish lineages, evolves through a combination of unique and shared gene expression patterns. Shared expression profiles reflect common environmental pressures, while unique expression likely reflects the fact that similar adaptive traits evolve through diverse genetic mechanisms.
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Affiliation(s)
- Bethany A Stahl
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio
| | - Joshua B Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio
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Wang X, Gong K, Li H, Wang C, Qu C, Li H. Gene Expression Profiling of the Optic Nerve Head of Patients with Primary Open-Angle Glaucoma. J Ophthalmol 2017; 2017:6896390. [PMID: 28484645 PMCID: PMC5397728 DOI: 10.1155/2017/6896390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/01/2017] [Accepted: 02/14/2017] [Indexed: 11/04/2022] Open
Abstract
Background. The pressure-induced axonal injury of the vulnerable ONH has led many researchers to view glaucoma from the perspective of the genetic basis of the angle of the ONH. However, genetic studies on POAG from this perspective are limited. Methods. Microarray dataset GSE45570 of the ONH of healthy individuals and POAG patients were downloaded from the Gene Expression Omnibus. After screening for the DEGs using the limma package, enrichment analysis was performed using DAVID. The DEG interaction network was constructed using cancer spider at BioProfiling.de. Thereafter, DEG-related TFs were predicted using TRANSFAC, and TF-DEG regulatory networks were visualized using Cytoscape. Results. Thirty-one DEGs were identified including 11 upregulated and 20 downregulated DEGs. Thereafter, gene ontology terms of nucleosome assembly, sensory perception and cognition, and pathway of signaling by GPCR were found to be enriched among the DEGs. Furthermore, DEG interaction and TF-DEG networks were constructed. NEUROD1 was present in both the DEG network and the TF-DEG network as the node with the highest degree and was predicted as a marker gene in the ONH of patients with POAG. Conclusion. NEUROD1 may contribute greatly to the ONH of patients with POAG and was found to be involved in eye development and diseases.
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Affiliation(s)
- Xinrong Wang
- Department of Ophthalmology, The Fourth Hospital of Xi'an, Xi'an, Shaanxi 710004, China
| | - Ke Gong
- Department of Ophthalmology, The Fourth Hospital of Xi'an, Xi'an, Shaanxi 710004, China
| | - Haiyan Li
- Department of Ophthalmology, The Fourth Hospital of Xi'an, Xi'an, Shaanxi 710004, China
| | - Congyi Wang
- Department of Ophthalmology, The Fourth Hospital of Xi'an, Xi'an, Shaanxi 710004, China
| | - Chaoyi Qu
- Department of Ophthalmology, The Fourth Hospital of Xi'an, Xi'an, Shaanxi 710004, China
| | - Hui Li
- Department of Endocrinology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, China
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Pei J, Grishin NV. Expansion of divergent SEA domains in cell surface proteins and nucleoporin 54. Protein Sci 2017; 26:617-630. [PMID: 27977898 DOI: 10.1002/pro.3096] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 12/13/2022]
Abstract
SEA (sea urchin sperm protein, enterokinase, agrin) domains, many of which possess autoproteolysis activity, have been found in a number of cell surface and secreted proteins. Despite high sequence divergence, SEA domains were also proposed to be present in dystroglycan based on a conserved autoproteolysis motif and receptor-type protein phosphatase IA-2 based on structural similarity. The presence of a SEA domain adjacent to the transmembrane segment appears to be a recurring theme in quite a number of type I transmembrane proteins on the cell surface, such as MUC1, dystroglycan, IA-2, and Notch receptors. By comparative sequence and structural analyses, we identified dystroglycan-like proteins with SEA domains in Capsaspora owczarzaki of the Filasterea group, one of the closest single-cell relatives of metazoans. We also detected novel and divergent SEA domains in a variety of cell surface proteins such as EpCAM, α/ε-sarcoglycan, PTPRR, collectrin/Tmem27, amnionless, CD34, KIAA0319, fibrocystin-like protein, and a number of cadherins. While these proteins are mostly from metazoans or their single cell relatives such as choanoflagellates and Filasterea, fibrocystin-like proteins with SEA domains were found in several other eukaryotic lineages including green algae, Alveolata, Euglenozoa, and Haptophyta, suggesting an ancient evolutionary origin. In addition, the intracellular protein Nucleoporin 54 (Nup54) acquired a divergent SEA domain in choanoflagellates and metazoans.
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Affiliation(s)
| | - Nick V Grishin
- Howard Hughes Medical Institute.,Department of Biophysics and Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390, USA
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Hunt NC, Hallam D, Karimi A, Mellough CB, Chen J, Steel DHW, Lako M. 3D culture of human pluripotent stem cells in RGD-alginate hydrogel improves retinal tissue development. Acta Biomater 2017; 49:329-343. [PMID: 27826002 DOI: 10.1016/j.actbio.2016.11.016] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 12/22/2022]
Abstract
No treatments exist to effectively treat many retinal diseases. Retinal pigmented epithelium (RPE) and neural retina can be generated from human embryonic stem cells/induced pluripotent stem cells (hESCs/hiPSCs). The efficacy of current protocols is, however, limited. It was hypothesised that generation of laminated neural retina and/or RPE from hiPSCs/hESCs could be enhanced by three dimensional (3D) culture in hydrogels. hiPSC- and hESC-derived embryoid bodies (EBs) were encapsulated in 0.5% RGD-alginate; 1% RGD-alginate; hyaluronic acid (HA) or HA/gelatin hydrogels and maintained until day 45. Compared with controls (no gel), 0.5% RGD-alginate increased: the percentage of EBs with pigmented RPE foci; the percentage EBs with optic vesicles (OVs) and pigmented RPE simultaneously; the area covered by RPE; frequency of RPE cells (CRALBP+); expression of RPE markers (TYR and RPE65) and the retinal ganglion cell marker, MATH5. Furthermore, 0.5% RGD-alginate hydrogel encapsulation did not adversely affect the expression of other neural retina markers (PROX1, CRX, RCVRN, AP2α or VSX2) as determined by qRT-PCR, or the percentage of VSX2 positive cells as determined by flow cytometry. 1% RGD-alginate increased the percentage of EBs with OVs and/or RPE, but did not significantly influence any other measures of retinal differentiation. HA-based hydrogels had no significant effect on retinal tissue development. The results indicated that derivation of retinal tissue from hESCs/hiPSCs can be enhanced by culture in 0.5% RGD-alginate hydrogel. This RGD-alginate scaffold may be useful for derivation, transport and transplantation of neural retina and RPE, and may also enhance formation of other pigmented, neural or epithelial tissue. STATEMENT OF SIGNIFICANCE The burden of retinal disease is ever growing with the increasing age of the world-wide population. Transplantation of retinal tissue derived from human pluripotent stem cells (PSCs) is considered a promising treatment. However, derivation of retinal tissue from PSCs using defined media is a lengthy process and often variable between different cell lines. This study indicated that alginate hydrogels enhanced retinal tissue development from PSCs, whereas hyaluronic acid-based hydrogels did not. This is the first study to show that 3D culture with a biomaterial scaffold can improve retinal tissue derivation from PSCs. These findings indicate potential for the clinical application of alginate hydrogels for the derivation and subsequent transplantation retinal tissue. This work may also have implications for the derivation of other pigmented, neural or epithelial tissue.
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Affiliation(s)
- Nicola C Hunt
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
| | - Ayesha Karimi
- Cumberland Infirmary, North Cumbria University Hospitals NHS Trust, Carlisle CA2 7HY, UK
| | - Carla B Mellough
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
| | - Jinju Chen
- School of Mechanical & Systems Engineering, Stephenson Building, Newcastle University, Newcastle upon Tyne, UK.
| | - David H W Steel
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK; Sunderland Eye Infirmary, Queen Alexandra Road, Sunderland SR2 9HP, UK.
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
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Ullah I, Kabir F, Iqbal M, Gottsch CBS, Naeem MA, Assir MZ, Khan SN, Akram J, Riazuddin S, Ayyagari R, Hejtmancik JF, Riazuddin SA. Pathogenic mutations in TULP1 responsible for retinitis pigmentosa identified in consanguineous familial cases. Mol Vis 2016; 22:797-815. [PMID: 27440997 PMCID: PMC4947966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 07/14/2016] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To identify pathogenic mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous familial cases. METHODS Seven large familial cases with multiple individuals diagnosed with retinitis pigmentosa were included in the study. Affected individuals in these families underwent ophthalmic examinations to document the symptoms and confirm the initial diagnosis. Blood samples were collected from all participating members, and genomic DNA was extracted. An exclusion analysis with microsatellite markers spanning the TULP1 locus on chromosome 6p was performed, and two-point logarithm of odds (LOD) scores were calculated. All coding exons along with the exon-intron boundaries of TULP1 were sequenced bidirectionally. We constructed a single nucleotide polymorphism (SNP) haplotype for the four familial cases harboring the K489R allele and estimated the likelihood of a founder effect. RESULTS The ophthalmic examinations of the affected individuals in these familial cases were suggestive of RP. Exclusion analyses confirmed linkage to chromosome 6p harboring TULP1 with positive two-point LOD scores. Subsequent Sanger sequencing identified the single base pair substitution in exon14, c.1466A>G (p.K489R), in four families. Additionally, we identified a two-base deletion in exon 4, c.286_287delGA (p.E96Gfs77*); a homozygous splice site variant in intron 14, c.1495+4A>C; and a novel missense variation in exon 15, c.1561C>T (p.P521S). All mutations segregated with the disease phenotype in the respective families and were absent in ethnically matched control chromosomes. Haplotype analysis suggested (p<10(-6)) that affected individuals inherited the causal mutation from a common ancestor. CONCLUSIONS Pathogenic mutations in TULP1 are responsible for the RP phenotype in seven familial cases with a common ancestral mutation responsible for the disease phenotype in four of the seven families.
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Affiliation(s)
- Inayat Ullah
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Firoz Kabir
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Muhammad Iqbal
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | | | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Muhammad Zaman Assir
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Shaheen N. Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan,Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Radha Ayyagari
- Shiley Eye Institute, University of California, San Diego, CA
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
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Khan KN, Mahroo OA, Khan RS, Mohamed MD, McKibbin M, Bird A, Michaelides M, Tufail A, Moore AT. Differentiating drusen: Drusen and drusen-like appearances associated with ageing, age-related macular degeneration, inherited eye disease and other pathological processes. Prog Retin Eye Res 2016; 53:70-106. [DOI: 10.1016/j.preteyeres.2016.04.008] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 04/24/2016] [Accepted: 04/27/2016] [Indexed: 12/11/2022]
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Bashar AE, Metcalfe AL, Viringipurampeer IA, Yanai A, Gregory-Evans CY, Gregory-Evans K. An ex vivo gene therapy approach in X-linked retinoschisis. Mol Vis 2016; 22:718-33. [PMID: 27390514 PMCID: PMC4919093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/22/2016] [Indexed: 10/28/2022] Open
Abstract
PURPOSE X-linked retinoschisis (XLRS) is juvenile-onset macular degeneration caused by haploinsufficiency of the extracellular cell adhesion protein retinoschisin (RS1). RS1 mutations can lead to either a non-functional protein or the absence of protein secretion, and it has been established that extracellular deficiency of RS1 is the underlying cause of the phenotype. Therefore, we hypothesized that an ex vivo gene therapy strategy could be used to deliver sufficient extracellular RS1 to reverse the phenotype seen in XLRS. Here, we used adipose-derived, syngeneic mesenchymal stem cells (MSCs) that were genetically modified to secrete human RS1 and then delivered these cells by intravitreal injection to the retina of the Rs1h knockout mouse model of XLRS. METHODS MSCs were electroporated with two transgene expression systems (cytomegalovirus (CMV)-controlled constitutive and doxycycline-induced Tet-On controlled inducible), both driving expression of human RS1 cDNA. The stably transfected cells, using either constitutive mesenchymal stem cell (MSC) or inducible MSC cassettes, were assayed for their RS1 secretion profile. For single injection studies, 100,000 genetically modified MSCs were injected into the vitreous cavity of the Rs1h knockout mouse eye at P21, and data were recorded at 2, 4, and 8 weeks post-injection. The control groups received either unmodified MSCs or vehicle injection. For the multiple injection studies, the mice received intravitreal MSC injections at P21, P60, and P90 with data collection at P120. For the single- and multiple-injection studies, the outcomes were measured with electroretinography, optokinetic tracking responses (OKT), histology, and immunohistochemistry. RESULTS Two lines of genetically modified MSCs were established and found to secrete RS1 at a rate of 8 ng/million cells/day. Following intravitreal injection, RS1-expressing MSCs were found mainly in the inner retinal layers. Two weeks after a single injection of MSCs, the area of the schisis cavities was reduced by 65% with constitutive MSCs and by 83% with inducible MSCs, demonstrating improved inner nuclear layer architecture. This benefit was maintained up to 8 weeks post-injection and corresponded to a significant improvement in the electroretinogram (ERG) b-/a-wave ratio at 8 weeks (2.6 inducible MSCs; 1.4 untreated eyes, p<0.05). At 4 months after multiple injections, the schisis cavity areas were reduced by 78% for inducible MSCs and constitutive MSCs, more photoreceptor nuclei were present (700/µm constitutive MSC; 750/µm inducible MSC; 383/µm untreated), and the ERG b-wave was significantly improved (threefold higher with constitutive MSCs and twofold higher with inducible MSCs) compared to the untreated control group. CONCLUSIONS These results establish that extracellular delivery of RS1 rescues the structural and functional deficits in the Rs1h knockout mouse model and that this ex vivo gene therapy approach can inhibit progression of disease. This proof-of-principle work suggests that other inherited retinal degenerations caused by a deficiency of extracellular matrix proteins could be targeted by this strategy.
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Kabir F, Ullah I, Ali S, Gottsch AD, Naeem MA, Assir MZ, Khan SN, Akram J, Riazuddin S, Ayyagari R, Hejtmancik JF, Riazuddin SA. Loss of function mutations in RP1 are responsible for retinitis pigmentosa in consanguineous familial cases. Mol Vis 2016; 22:610-25. [PMID: 27307693 PMCID: PMC4901054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 06/08/2016] [Indexed: 10/31/2022] Open
Abstract
PURPOSE This study was undertaken to identify causal mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous families. METHODS Large consanguineous families were ascertained from the Punjab province of Pakistan. An ophthalmic examination consisting of a fundus evaluation and electroretinography (ERG) was completed, and small aliquots of blood were collected from all participating individuals. Genomic DNA was extracted from white blood cells, and a genome-wide linkage or a locus-specific exclusion analysis was completed with polymorphic short tandem repeats (STRs). Two-point logarithm of odds (LOD) scores were calculated, and all coding exons and exon-intron boundaries of RP1 were sequenced to identify the causal mutation. RESULTS The ophthalmic examination showed that affected individuals in all families manifest cardinal symptoms of RP. Genome-wide scans localized the disease phenotype to chromosome 8q, a region harboring RP1, a gene previously implicated in the pathogenesis of RP. Sanger sequencing identified a homozygous single base deletion in exon 4: c.3697delT (p.S1233Pfs22*), a single base substitution in intron 3: c.787+1G>A (p.I263Nfs8*), a 2 bp duplication in exon 2: c.551_552dupTA (p.Q185Yfs4*) and an 11,117 bp deletion that removes all three coding exons of RP1. These variations segregated with the disease phenotype within the respective families and were not present in ethnically matched control samples. CONCLUSIONS These results strongly suggest that these mutations in RP1 are responsible for the retinal phenotype in affected individuals of all four consanguineous families.
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Affiliation(s)
- Firoz Kabir
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Inayat Ullah
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Shahbaz Ali
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | | | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Muhammad Zaman Assir
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Shaheen N. Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan,Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Radha Ayyagari
- Shiley Eye Institute, University of California, San Diego, CA
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
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