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Smirnov VM, Robert MP, Condroyer C, Navarro J, Antonio A, Rozet JM, Sahel JA, Perrault I, Audo I, Zeitz C. Association of Missense Variants in VSX2 With a Peculiar Form of Congenital Stationary Night Blindness Affecting All Bipolar Cells. JAMA Ophthalmol 2022; 140:1163-1173. [PMID: 36264558 PMCID: PMC9585472 DOI: 10.1001/jamaophthalmol.2022.4146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/23/2022] [Indexed: 01/12/2023]
Abstract
Importance Congenital stationary night blindness (CSNB) is an inherited stationary retinal disorder that is clinically and genetically heterogeneous. To date, the genetic association between some cases with CSNB and an unusual complex clinical picture is unclear. Objective To describe an unreported CSNB phenotype and the associated gene defect in 3 patients from 2 unrelated families. Design, Setting, and Participants This retrospective case series was conducted in 2021 and 2022 at a national referral center for rare ocular diseases. Data for 3 patients from a cohort of 140 genetically unsolved CSNB cases were analyzed clinically and genetically. Exposures Complete ocular examination including full-field electroretinography and multimodal fundus imaging (spectral-domain optical coherence tomography, color, infrared reflectance, and short-wavelength autofluorescence photographs) were performed. The gene defect was identified by exome sequencing and confirmed by Sanger sequencing and co-segregation analysis in 1 family. Screening was performed for genetically unsolved CSNB cases for VSX2 variants by direct Sanger sequencing. Main Outcomes and Measures Ocular and molecular biology findings. Results The series included 3 patients whose clinical investigations occurred at ages in the early 30s, younger than 12 years, and in the mid 40s. They had nystagmus, low stable visual acuity, and myopia from birth and experienced night blindness. Two older patients had bilateral lens luxation and underwent lens extraction. Full-field electroretinography revealed an electronegative Schubert-Bornschein appearance, combining characteristics of incomplete and complete CSNB, affecting the function of rod and cone ON- and OFF-bipolar cells. Exome sequencing and co-segregation analysis in a consanguineous family with 2 affected members identified a homozygous variant in VSX2. Subsequently, screening of the CSNB cohort identified another unrelated patient harboring a distinct VSX2 variant. Conclusions and Relevance This case series revealed a peculiar pan-bipolar cell retinopathy with lens luxation associated with variants in VSX2. Clinicians should be aware of this association and VSX2 added to CSNB diagnostic gene panels.
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Affiliation(s)
- Vasily M. Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Université de Lille, Faculté de Médecine, Lille, France
- Exploration de la Vision et Neuro-Ophtalmologie, CHU de Lille, Lille, France
| | - Matthieu P. Robert
- Ophthalmology Department, Hôpital Universitaire Necker-Enfants Malades, Paris, France
- Borelli Centre, UMR 9010, CNRS-SSA-ENS Paris Saclay-Paris University, Gif-sur-Yvette, France
| | | | - Julien Navarro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Aline Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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Markitantova Y, Simirskii V. Inherited Eye Diseases with Retinal Manifestations through the Eyes of Homeobox Genes. Int J Mol Sci 2020; 21:E1602. [PMID: 32111086 PMCID: PMC7084737 DOI: 10.3390/ijms21051602] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
Retinal development is under the coordinated control of overlapping networks of signaling pathways and transcription factors. The paper was conceived as a review of the data and ideas that have been formed to date on homeobox genes mutations that lead to the disruption of eye organogenesis and result in inherited eye/retinal diseases. Many of these diseases are part of the same clinical spectrum and have high genetic heterogeneity with already identified associated genes. We summarize the known key regulators of eye development, with a focus on the homeobox genes associated with monogenic eye diseases showing retinal manifestations. Recent advances in the field of genetics and high-throughput next-generation sequencing technologies, including single-cell transcriptome analysis have allowed for deepening of knowledge of the genetic basis of inherited retinal diseases (IRDs), as well as improve their diagnostics. We highlight some promising avenues of research involving molecular-genetic and cell-technology approaches that can be effective for IRDs therapy. The most promising neuroprotective strategies are aimed at mobilizing the endogenous cellular reserve of the retina.
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Norrie JL, Lupo MS, Xu B, Al Diri I, Valentine M, Putnam D, Griffiths L, Zhang J, Johnson D, Easton J, Shao Y, Honnell V, Frase S, Miller S, Stewart V, Zhou X, Chen X, Dyer MA. Nucleome Dynamics during Retinal Development. Neuron 2019; 104:512-528.e11. [PMID: 31493975 PMCID: PMC6842117 DOI: 10.1016/j.neuron.2019.08.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 06/02/2019] [Accepted: 07/29/2019] [Indexed: 01/28/2023]
Abstract
More than 8,000 genes are turned on or off as progenitor cells produce the 7 classes of retinal cell types during development. Thousands of enhancers are also active in the developing retinae, many having features of cell- and developmental stage-specific activity. We studied dynamic changes in the 3D chromatin landscape important for precisely orchestrated changes in gene expression during retinal development by ultra-deep in situ Hi-C analysis on murine retinae. We identified developmental-stage-specific changes in chromatin compartments and enhancer-promoter interactions. We developed a machine learning-based algorithm to map euchromatin and heterochromatin domains genome-wide and overlaid it with chromatin compartments identified by Hi-C. Single-cell ATAC-seq and RNA-seq were integrated with our Hi-C and previous ChIP-seq data to identify cell- and developmental-stage-specific super-enhancers (SEs). We identified a bipolar neuron-specific core regulatory circuit SE upstream of Vsx2, whose deletion in mice led to the loss of bipolar neurons.
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Affiliation(s)
- Jackie L Norrie
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Marybeth S Lupo
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Beisi Xu
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Issam Al Diri
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Marc Valentine
- Cytogenetics Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Daniel Putnam
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Lyra Griffiths
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jiakun Zhang
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Dianna Johnson
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - John Easton
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ying Shao
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Victoria Honnell
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Sharon Frase
- Cellular Imaging Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Shondra Miller
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Valerie Stewart
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xin Zhou
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xiang Chen
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Michael A Dyer
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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Al‐Dewik N, Al‐Mureikhi M, Shahbeck N, Ali R, Al‐Mesaifri F, Mahmoud L, Othman A, AlMulla M, Sulaiman RA, Musa S, Abdoh G, El‐Akouri K, Solomon BD, Ben‐Omran T. Clinical genetics and genomic medicine in Qatar. Mol Genet Genomic Med 2018; 6:702-712. [PMID: 30264509 PMCID: PMC6160705 DOI: 10.1002/mgg3.474] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 08/23/2018] [Indexed: 01/16/2023] Open
Abstract
Clinical genetics and genomic medicine in Qatar.
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Affiliation(s)
- Nader Al‐Dewik
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Mariam Al‐Mureikhi
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Noora Shahbeck
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Rehab Ali
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Fatma Al‐Mesaifri
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Laila Mahmoud
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Amna Othman
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Mariam AlMulla
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Reem Al Sulaiman
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Sara Musa
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | - Ghassan Abdoh
- Department of PediatricsNewborn Screening UnitHamad Medical CorporationDohaQatar
| | - Karen El‐Akouri
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
| | | | - Tawfeg Ben‐Omran
- Section of Clinical and Metabolic GeneticsDepartment of PediatricsHamad Medical CorporationDohaQatar
- Weill Cornell Medical CollegeDohaQatar
- Sidra MedicineDohaQatar
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5
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Genetic architecture of natural variation in visual senescence in Drosophila. Proc Natl Acad Sci U S A 2016; 113:E6620-E6629. [PMID: 27791033 DOI: 10.1073/pnas.1613833113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Senescence, i.e., functional decline with age, is a major determinant of health span in a rapidly aging population, but the genetic basis of interindividual variation in senescence remains largely unknown. Visual decline and age-related eye disorders are common manifestations of senescence, but disentangling age-dependent visual decline in human populations is challenging due to inability to control genetic background and variation in histories of environmental exposures. We assessed the genetic basis of natural variation in visual senescence by measuring age-dependent decline in phototaxis using Drosophila melanogaster as a genetic model system. We quantified phototaxis at 1, 2, and 4 wk of age in the sequenced, inbred lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) and found an average decline in phototaxis with age. We observed significant genetic variation for phototaxis at each age and significant genetic variation in senescence of phototaxis that is only partly correlated with phototaxis. Genome-wide association analyses in the DGRP and a DGRP-derived outbred, advanced intercross population identified candidate genes and genetic networks associated with eye and nervous system development and function, including seven genes with human orthologs previously associated with eye diseases. Ninety percent of candidate genes were functionally validated with targeted RNAi-mediated suppression of gene expression. Absence of candidate genes previously implicated with longevity indicates physiological systems may undergo senescence independent of organismal life span. Furthermore, we show that genes that shape early developmental processes also contribute to senescence, demonstrating that senescence is part of a genetic continuum that acts throughout the life span.
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Capowski EE, Wright LS, Liang K, Phillips MJ, Wallace K, Petelinsek A, Hagstrom A, Pinilla I, Borys K, Lien J, Min JH, Keles S, Thomson JA, Gamm DM. Regulation of WNT Signaling by VSX2 During Optic Vesicle Patterning in Human Induced Pluripotent Stem Cells. Stem Cells 2016; 34:2625-2634. [PMID: 27301076 DOI: 10.1002/stem.2414] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/28/2016] [Indexed: 12/22/2022]
Abstract
Few gene targets of Visual System Homeobox 2 (VSX2) have been identified despite its broad and critical role in the maintenance of neural retina (NR) fate during early retinogenesis. We performed VSX2 ChIP-seq and ChIP-PCR assays on early stage optic vesicle-like structures (OVs) derived from human iPS cells (hiPSCs), which highlighted WNT pathway genes as direct regulatory targets of VSX2. Examination of early NR patterning in hiPSC-OVs from a patient with a functional null mutation in VSX2 revealed mis-expression and upregulation of WNT pathway components and retinal pigmented epithelium (RPE) markers in comparison to control hiPSC-OVs. Furthermore, pharmacological inhibition of WNT signaling rescued the early mutant phenotype, whereas augmentation of WNT signaling in control hiPSC-OVs phenocopied the mutant. These findings reveal an important role for VSX2 as a regulator of WNT signaling and suggest that VSX2 may act to maintain NR identity at the expense of RPE in part by direct repression of WNT pathway constituents. Stem Cells 2016;34:2625-2634.
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Affiliation(s)
| | - Lynda S Wright
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Kun Liang
- Statistics and Actuarial Science, University of Waterloo, Waterloo, ON, Canada
| | - M Joseph Phillips
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Kyle Wallace
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Anna Petelinsek
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Anna Hagstrom
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Isabel Pinilla
- Aragon Institute for Health Research (IIS Aragón), Lozano Blesa University Hospital, Zaragoza, 50009, Spain.,Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza, 50009, Spain
| | - Katarzyna Borys
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jessica Lien
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jee Hong Min
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Sunduz Keles
- Department of Statistics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | | | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA.,Department of Ophthamology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
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7
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Wright LS, Pinilla I, Saha J, Clermont JM, Lien JS, Borys KD, Capowski EE, Phillips MJ, Gamm DM. VSX2 and ASCL1 Are Indicators of Neurogenic Competence in Human Retinal Progenitor Cultures. PLoS One 2015; 10:e0135830. [PMID: 26292211 PMCID: PMC4546156 DOI: 10.1371/journal.pone.0135830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 07/27/2015] [Indexed: 01/09/2023] Open
Abstract
Three dimensional (3D) culture techniques are frequently used for CNS tissue modeling and organoid production, including generation of retina-like tissues. A proposed advantage of these 3D systems is their potential to more closely approximate in vivo cellular microenvironments, which could translate into improved manufacture and/or maintenance of neuronal populations. Visual System Homeobox 2 (VSX2) labels all multipotent retinal progenitor cells (RPCs) and is known to play important roles in retinal development. In contrast, the proneural transcription factor Acheate scute-like 1 (ASCL1) is expressed transiently in a subset of RPCs, but is required for the production of most retinal neurons. Therefore, we asked whether the presence of VSX2 and ASCL1 could gauge neurogenic potential in 3D retinal cultures derived from human prenatal tissue or ES cells (hESCs). Short term prenatal 3D retinal cultures displayed multiple characteristics of human RPCs (hRPCs) found in situ, including robust expression of VSX2. Upon initiation of hRPC differentiation, there was a small increase in co-labeling of VSX2+ cells with ASCL1, along with a modest increase in the number of PKCα+ neurons. However, 3D prenatal retinal cultures lost expression of VSX2 and ASCL1 over time while concurrently becoming refractory to neuronal differentiation. Conversely, 3D optic vesicles derived from hESCs (hESC-OVs) maintained a robust VSX2+ hRPC population that could spontaneously co-express ASCL1 and generate photoreceptors and other retinal neurons for an extended period of time. These results show that VSX2 and ASCL1 can serve as markers for neurogenic potential in cultured hRPCs. Furthermore, unlike hESC-OVs, maintenance of 3D structure does not independently convey an advantage in the culture of prenatal hRPCs, further illustrating differences in the survival and differentiation requirements of hRPCs extracted from native tissue vs. those generated entirely in vitro.
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Affiliation(s)
- Lynda S. Wright
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza, Spain
- Aragones Health Sciences Institute, Zaragoza, Spain
| | - Jishnu Saha
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Joshua M. Clermont
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- New England College of Optometry, Boston, Massachusetts, United States of America
| | - Jessica S. Lien
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Katarzyna D. Borys
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Elizabeth E. Capowski
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - M. Joseph Phillips
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
| | - David M. Gamm
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail:
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Sigulinsky CL, German ML, Leung AM, Clark AM, Yun S, Levine EM. Genetic chimeras reveal the autonomy requirements for Vsx2 in embryonic retinal progenitor cells. Neural Dev 2015; 10:12. [PMID: 25927996 PMCID: PMC4450477 DOI: 10.1186/s13064-015-0039-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/14/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Vertebrate retinal development is a complex process, requiring the specification and maintenance of retinal identity, proliferative expansion of retinal progenitor cells (RPCs), and their differentiation into retinal neurons and glia. The homeobox gene Vsx2 is expressed in RPCs and required for the proper execution of this retinal program. However, our understanding of the mechanisms by which Vsx2 does this is still rudimentary. To define the autonomy requirements for Vsx2 in the regulation of RPC properties, we generated chimeric mouse embryos comprised of wild-type and Vsx2-deficient cells. RESULTS We show that Vsx2 maintains retinal identity in part through the cell-autonomous repression of the retinal pigment epithelium determinant Mitf, and that Lhx2 is required cell autonomously for the ectopic Mitf expression in Vsx2-deficient cells. We also found significant cell-nonautonomous contributions to Vsx2-mediated regulation of RPC proliferation, pointing to an important role for Vsx2 in establishing a growth-promoting extracellular environment. Additionally, we report a cell-autonomous requirement for Vsx2 in controlling when neurogenesis is initiated, indicating that Vsx2 is an important mediator of neurogenic competence. Finally, the distribution of wild-type cells shifted away from RPCs and toward retinal ganglion cell precursors in patches of high Vsx2-deficient cell density to potentially compensate for the lack of fated precursors in these areas. CONCLUSIONS Through the generation and analysis of genetic chimeras, we demonstrate that Vsx2 utilizes both cell-autonomous and cell-nonautonomous mechanisms to regulate progenitor properties in the embryonic retina. Importantly, Vsx2's role in regulating Mitf is in part separable from its role in promoting proliferation, and proliferation is excluded as the intrinsic timer that determines when neurogenesis is initiated. These findings highlight the complexity of Vsx2 function during retinal development and provide a framework for identifying the molecular mechanisms mediating these functions.
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Affiliation(s)
- Crystal L Sigulinsky
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Interdepartmental Program in Neuroscience, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Massiell L German
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Amanda M Leung
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Anna M Clark
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Sanghee Yun
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Edward M Levine
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
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Phillips MJ, Perez ET, Martin JM, Reshel ST, Wallace KA, Capowski EE, Singh R, Wright LS, Clark EM, Barney PM, Stewart R, Dickerson SJ, Miller MJ, Percin EF, Thomson JA, Gamm DM. Modeling human retinal development with patient-specific induced pluripotent stem cells reveals multiple roles for visual system homeobox 2. Stem Cells 2015; 32:1480-92. [PMID: 24532057 DOI: 10.1002/stem.1667] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/07/2014] [Accepted: 01/12/2014] [Indexed: 12/14/2022]
Abstract
Human induced pluripotent stem cells (hiPSCs) have been shown to differentiate along the retinal lineage in a manner that mimics normal mammalian development. Under certain culture conditions, hiPSCs form optic vesicle-like structures (OVs), which contain proliferating progenitors capable of yielding all neural retina (NR) cell types over time. Such observations imply conserved roles for regulators of retinogenesis in hiPSC-derived cultures and the developing embryo. However, whether and to what extent this assumption holds true has remained largely uninvestigated. We examined the role of a key NR transcription factor, visual system homeobox 2 (VSX2), using hiPSCs derived from a patient with microphthalmia caused by an R200Q mutation in the VSX2 homeodomain region. No differences were noted between (R200Q)VSX2 and sibling control hiPSCs prior to OV generation. Thereafter, (R200Q)VSX2 hiPSC-OVs displayed a significant growth deficit compared to control hiPSC-OVs, as well as increased production of retinal pigmented epithelium at the expense of NR cell derivatives. Furthermore, (R200Q)VSX2 hiPSC-OVs failed to produce bipolar cells, a distinctive feature previously observed in Vsx2 mutant mice. (R200Q)VSX2 hiPSC-OVs also demonstrated delayed photoreceptor maturation, which could be overcome via exogenous expression of wild-type VSX2 at early stages of retinal differentiation. Finally, RNAseq analysis on isolated hiPSC-OVs implicated key transcription factors and extracellular signaling pathways as potential downstream effectors of VSX2-mediated gene regulation. Our results establish hiPSC-OVs as versatile model systems to study retinal development at stages not previously accessible in humans and support the bona fide nature of hiPSC-OV-derived retinal progeny.
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Affiliation(s)
- M Joseph Phillips
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Williamson KA, FitzPatrick DR. The genetic architecture of microphthalmia, anophthalmia and coloboma. Eur J Med Genet 2014; 57:369-80. [PMID: 24859618 DOI: 10.1016/j.ejmg.2014.05.002] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 05/14/2014] [Indexed: 10/25/2022]
Abstract
Microphthalmia, anophthalmia and coloboma (MAC) are distinct phenotypes that represent a continuum of structural developmental eye defects. In severe bilateral cases (anophthalmia or severe microphthalmia) the genetic cause is now identifiable in approximately 80 percent of cases, with de novo heterozygous loss-of-function mutations in SOX2 or OTX2 being the most common. The genetic cause of other forms of MAC, in particular isolated coloboma, remains unknown in the majority of cases. This review will focus on MAC phenotypes that are associated with mutation of the genes SOX2, OTX2, PAX6, STRA6, ALDH1A3, RARB, VSX2, RAX, FOXE3, BMP4, BMP7, GDF3, GDF6, ABCB6, ATOH7, C12orf57, TENM3 (ODZ3), and VAX1. Recently reported mutation of the SALL2 and YAP1 genes are discussed in brief. Clinical and genetic features were reviewed in a total of 283 unrelated MAC cases or families that were mutation-positive from these 20 genes. Both the relative frequency of mutations in MAC cohort screens and the level of confidence in the assignment of disease-causing status were evaluated for each gene.
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Affiliation(s)
- Kathleen A Williamson
- Medical Research Council Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - David R FitzPatrick
- Medical Research Council Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK.
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Khan AO, Aldahmesh MA, Noor J, Salem A, Alkuraya FS. Lens subluxation and retinal dysfunction in a girl with homozygous VSX2 mutation. Ophthalmic Genet 2013; 36:8-13. [PMID: 24001013 DOI: 10.3109/13816810.2013.827217] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To describe a unique lens subluxation phenotype in a child from a consanguineous family and to determine its genetic basis. METHODS Ophthalmologic examination (including ocular biometry and electroretinography [ERG] for the proband) and autozygosity-analysis-guided exome sequencing for the family; confirmatory candidate gene sequencing in the family and ethnically matched controls. RESULTS An otherwise healthy 3-year-old Saudi Arabian girl with poor vision since birth had smooth irides, lens subluxation, cone-rod dysfunction, and high myopia - features resembling Knobloch syndrome but differing in regard to direction of lens subluxation (superior rather than temporal) and the pattern of chorioretinal atrophy (without vitreous condensations or distinct macular atrophy). Autozygome-guided exome sequencing revealed the girl to harbor a homozygous exon 5 mutation in the ocular transcription factor gene visual homeobox 2 (VSX2) [c.773delA; p.Lys258SerfsX44] that was heterozygous in the unaffected brother and parents and absent in 100 healthy ethnically matched controls and on-line databases. Previously reported VSX2 mutations have affected the DNA-binding domains and only been associated with microphthalmia. Unlike previously reported mutations, the current VSX2 mutation is downstream to the protein's DNA binding domains. CONCLUSIONS The phenotype of this girl is unique and suggests a normal regulatory role for VSX2 in iris, zonule, and cone-rod development. For a consanguineous family with suspected recessive ocular disease but without a clear candidate gene, autozygome-guided exome analysis is a powerful technique, even when only a single patient is affected.
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Affiliation(s)
- Arif O Khan
- Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital , Riyadh , Saudi Arabia
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Posterior microphthalmia and nanophthalmia in Tunisia caused by a founder c.1059_1066insC mutation of the PRSS56 gene. Gene 2013; 528:288-94. [PMID: 23820083 DOI: 10.1016/j.gene.2013.06.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 06/10/2013] [Indexed: 01/08/2023]
Abstract
Congenital microphthalmia (CMIC) is a common developmental ocular disorder characterized by a small, and sometimes malformed, eye. Posterior microphthalmia (PM) and nanophthalmia are two rare subtypes of isolated CMIC characterized by extreme hyperopia due to short axial length and elevated lens/eye volume ratio. While nanophthalmia is associated with a reduced size in both anterior and posterior segments, PM involves a normal-size anterior chamber but a small posterior segment. Several genes encoding transcription and non-transcription regulators have been identified in different forms of CMIC. MFRP gene mutations have, for instance, been associated with nanophthalmia, and mutations in the recently identified PRSS56 gene have been linked to PM. So far, these two forms of CMIC have been associated with 9 mutations in PRSS56. Of particular interest, a c.1059_1066insC mutation has recently been reported in four Tunisian families with isolated PM and one Tunisian family with nanophthalmia. Here, we performed a genome-wide scan using a high density single nucleotide polymorphism (SNP) array 50 K in a large consanguineous Tunisian family (PM7) affected with PM and identified the same causative disease mutation. A total of 24 polymorphic markers spanning the PRSS56 gene in 6 families originating from different regions of Tunisia were analyzed to investigate the origin of the c.1059_1066insC mutation and to determine whether it arose in a common ancestor. A highly significant disease-associated haplotype, spanning across the 146 kb of the 2q37.1 chromosome, was conserved in those families, suggesting that c.1059_1066insC arose from a common founder. The age of the mutation in this haplotype was estimated to be around 1,850 years. The identification of such 'founder effects' may greatly simplify diagnostic genetic screening and lead to better prognostic counseling.
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Zou C, Levine EM. Vsx2 controls eye organogenesis and retinal progenitor identity via homeodomain and non-homeodomain residues required for high affinity DNA binding. PLoS Genet 2012; 8:e1002924. [PMID: 23028343 PMCID: PMC3447932 DOI: 10.1371/journal.pgen.1002924] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/05/2012] [Indexed: 12/26/2022] Open
Abstract
The homeodomain and adjacent CVC domain in the visual system homeobox (VSX) proteins are conserved from nematodes to humans. Humans with missense mutations in these regions of VSX2 have microphthalmia, suggesting both regions are critical for function. To assess this, we generated the corresponding mutations in mouse Vsx2. The homeodomain mutant protein lacked DNA binding activity and the knock-in mutant phenocopied the null mutant, ocular retardation J. The CVC mutant protein exhibited weakened DNA binding; and, although the corresponding knock-in allele was recessive, it unexpectedly caused the strongest phenotype, as indicated by severe microphthalmia and hyperpigmentation of the neural retina. This occurred through a cryptic transcriptional feedback loop involving the transcription factors Mitf and Otx1 and the Cdk inhibitor p27Kip1. Our data suggest that the phenotypic severity of the CVC mutant depends on the weakened DNA binding activity elicited by the CVC mutation and a previously unknown protein interaction between Vsx2 and its regulatory target Mitf. Our data also suggest that an essential function of the CVC domain is to assist the homeodomain in high-affinity DNA binding, which is required for eye organogenesis and unhindered execution of the retinal progenitor program in mammals. Finally, the genetic and phenotypic behaviors of the CVC mutation suggest it has the characteristics of a recessive neomorph, a rare type of genetic allele. Problems with the early development of the mammalian retina can cause congenital eye defects such as microphthalmia, in which the eye is dramatically smaller and functionally compromised. Severe microphthalmia is associated with mutations in the retinal-expressed visual system homeobox 2 (Vsx2) gene, but how Vsx2 controls retinal development, and ultimately eye formation, has remained unclear. We assessed the impact of two missense mutations, discovered in humans, on Vsx2 function and eye development in mice. One mutation altered a highly conserved residue of the homeodomain, and the other altered a highly conserved residue in the CVC domain, a region of unresolved function. Both mutations impacted the DNA binding properties of the protein, although to differing extents. Likewise, both mutations caused microphthalmia and disruptions in retinal development, also to differing extents and by distinct mechanisms. Our data suggest that Vsx2 acts as a gatekeeper of the retinal gene expression program by preventing the activation of interfering or competing gene expression programs. We propose that the evolutionary stable association between the VSX-class homeodomain and CVC domain set the stage for Vsx2 or its archetype to assume a gatekeeper function for retinal development and ultimately eye organogenesis.
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Affiliation(s)
- Changjiang Zou
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
| | - Edward M. Levine
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Use of genome-wide SNP homozygosity mapping in small pedigrees to identify new mutations in VSX2 causing recessive microphthalmia and a semidominant inner retinal dystrophy. Hum Genet 2010; 128:51-60. [DOI: 10.1007/s00439-010-0823-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Accepted: 04/01/2010] [Indexed: 01/08/2023]
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Reis LM, Tyler RC, Schneider A, Bardakjian T, Stoler JM, Melancon SB, Semina EV. FOXE3 plays a significant role in autosomal recessive microphthalmia. Am J Med Genet A 2010; 152A:582-90. [PMID: 20140963 DOI: 10.1002/ajmg.a.33257] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
FOXE3 forkhead transcription factor is essential to lens development in vertebrates. The eyes of Foxe3/foxe3-deficient mice and zebrafish fail to develop normally. In humans, autosomal dominant and recessive mutations in FOXE3 have been associated with variable phenotypes including anterior segment anomalies, cataract, and microphthalmia. We undertook sequencing of FOXE3 in 116 probands with a spectrum of ocular defects ranging from anterior segment dysgenesis and cataract to anophthalmia/microphthalmia. Recessive mutations in FOXE3 were found in four of 26 probands affected with bilateral microphthalmia (15% of all bilateral microphthalmia and 100% of consanguineous families with this phenotype). FOXE3-positive microphthalmia was accompanied by aphakia and/or corneal defects; no other associated systemic anomalies were observed in FOXE3-positive families. The previously reported c.720C > A (p.C240X) nonsense mutation was identified in two additional families in our sample and therefore appears to be recurrent, now reported in three independent microphthalmia families of varied ethnic backgrounds. Several missense variants were identified at varying frequencies in patient and control groups with some apparently being race-specific, which underscores the importance of utilizing race/ethnicity-matched control populations in evaluating the relevance of genetic screening results. In conclusion, FOXE3 mutations represent an important cause of nonsyndromic autosomal recessive bilateral microphthalmia.
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Affiliation(s)
- Linda M Reis
- Department of Pediatrics and Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin 53226, USA
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A genome-wide linkage scan in Tunisian families identifies a novel locus for non-syndromic posterior microphthalmia to chromosome 2q37.1. Hum Genet 2009; 126:575-87. [PMID: 19526372 DOI: 10.1007/s00439-009-0688-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 05/16/2009] [Indexed: 10/20/2022]
Abstract
Posterior microphthalmia (PM) is a relatively rare autosomal recessive condition with normal anterior segment and small posterior segment resulting in high hyperopia and retinal folding. It is an uncommon subtype of microphthalmia that has been mostly reported to coexist with several other ophthalmic conditions and to occur in sporadic cases. The membrane-type frizzled-related protein (MFRP) is the only gene so far reported implicated in autosomal recessive, non-syndromic and syndromic forms of PM. Here, we performed a clinical and genetic analysis using six consanguineous families ascertained from different regions of Tunisia and affected with non-syndromic PM that segregates as an autosomal recessive trait. To identify the disease-causing defect in these families, we first analysed MFRP gene, then some candidate genes (CHX10, OPA1, MITF, SOX2, CRYBB1-3 and CRYBA4) and loci (MCOP1, NNO1 and NNO2) previously implicated in different forms of microphthalmia. After exclusion of these genes and loci, we performed a genome-wide scan using a high density single nucleotide polymorphism (SNP) array 50 K in a large consanguineous pedigree. SNP genotyping revealed eight homozygous candidate regions on chromosomes 1, 2, 3, 6, 15, 17 and 21. Linkage analysis with additional microsatellite markers only retained the 2q37.1 region with a maximum LOD score of 8.85 obtained for D2S2344 at theta = 0.00. Further investigations are compatible for linkage of four more families to this region with a refined critical interval of 2.35 Mb. The screening of five candidate genes SAG, PDE6D, CHRND, CHRNG and IRK13 did not reveal any disease-causing mutation.
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