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Sechrest ER, Barbera RJ, Ma X, Dyka F, Ahn J, Brothers BA, Cahill ME, Hall I, Baehr W, Deng WT. Expression of red/green-cone opsin mutants K82E, P187S, M273K result in unique pathobiological perturbations to cone structure and function. Front Neurosci 2024; 18:1368089. [PMID: 38410159 PMCID: PMC10895044 DOI: 10.3389/fnins.2024.1368089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 01/23/2024] [Indexed: 02/28/2024] Open
Abstract
Long-and middle-wavelength cone photoreceptors, which are responsible for our visual acuity and color vision, comprise ~95% of our total cone population and are concentrated in the fovea of our retina. Previously, we characterized the disease mechanisms of the L/M-cone opsin missense mutations N94K, W177R, P307L, R330Q and G338E, all of which are associated with congenital blue cone monochromacy (BCM) or color-vision deficiency. Here, we used a similar viral vector-based gene delivery approach in M-opsin knockout mice to investigate the pathogenic consequences of the BCM or color-vision deficient associated L-cone opsin (OPN1LW) mutants K82E, P187S, and M273K. We investigated their subcellular localization, the pathogenic effects on cone structure, function, and cone viability. K82E mutants were detected predominately in cone outer segments, and its expression partially restored expression and correct localization of cone PDE6α' and cone transducin γ. As a result, K82E also demonstrated the ability to mediate cone light responses. In contrast, expression of P187S was minimally detected by either western blot or by immunohistochemistry, probably due to efficient degradation of the mutant protein. M273K cone opsin appeared to be misfolded as it was primarily localized to the cone inner segment and endoplasmic reticulum. Additionally, M273K did not restore the expression of cone PDE6α' and cone transducin γ in dorsal cone OS, presumably by its inability to bind 11-cis retinal. Consistent with the observed expression pattern, P187S and M273K cone opsin mutants were unable to mediate light responses. Moreover, expression of K82E, P187S, and M273K mutants reduced cone viability. Due to the distinct expression patterns and phenotypic differences of these mutants observed in vivo, we suggest that the pathobiological mechanisms of these mutants are distinct.
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Affiliation(s)
- Emily R. Sechrest
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, United States
| | - Robert J. Barbera
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, United States
| | - Xiaojie Ma
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Frank Dyka
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Junyeop Ahn
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States
| | - Brooke A. Brothers
- Department of Biochemistry, West Virginia University, Morgantown, WV, United States
| | - Marion E. Cahill
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, United States
- Department of Biology, West Virginia University, Morgantown, WV, United States
| | - Isaac Hall
- Department of Natural Sciences, Fairmont State University, Fairmont, WV, United States
| | - Wolfgang Baehr
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, UT, United States
- Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, UT, United States
- Department of Biology, University of Utah, Salt Lake City, UT, United States
| | - Wen-Tao Deng
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, United States
- Department of Biochemistry, West Virginia University, Morgantown, WV, United States
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Sechrest ER, Ma X, Cahill ME, Barbera RJ, Wang Y, Deng WT. Structural and functional rescue of cones carrying the most common cone opsin C203R missense mutation. JCI Insight 2024; 9:e172834. [PMID: 38060327 PMCID: PMC10906232 DOI: 10.1172/jci.insight.172834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 12/05/2023] [Indexed: 01/24/2024] Open
Abstract
An arginine to cysteine substitution at amino acid position 203 (C203R) is the most common missense mutation in human cone opsin. Linked to color blindness and blue cone monochromacy (BCM), C203 is involved in a crucial disulfide bond required for proper folding. It has previously been postulated that expression of mutant C203R cone opsin exerts a toxic effect on cone photoreceptors, similar to some well-characterized missense mutations in rhodopsin that lead to protein misfolding. In this study, we generated and characterized a BCM mouse model carrying the equivalent C203R mutation (Opn1mwC198R Opn1sw-/-) to investigate the disease mechanism and develop a gene therapy approach for this disorder. Untreated Opn1mwC198R Opn1sw-/- cones phenocopied affected cones in human patients with the equivalent mutation, exhibiting shortened or absent cone outer segments and loss of function. We determined that gene augmentation targeting cones specifically yielded robust rescue of cone function and structure when Opn1mwC198R Opn1sw-/- mice were treated at early ages. Importantly, treated cones displayed elaborated outer segments and replenished expression of crucial cone phototransduction proteins. Interestingly, we were unable to detect OPN1MWC198R mutant opsin at any age. We believe this is the first proof-of-concept study exploring the efficacy of gene therapy in BCM associated with a C203R mutation.
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Affiliation(s)
- Emily R. Sechrest
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Xiaojie Ma
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Marion E. Cahill
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA
- Department of Biology and
| | - Robert J. Barbera
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Yixiao Wang
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Wen-Tao Deng
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
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Yang Z, Yan L, Zhang W, Qi J, An W, Yao K. Dyschromatopsia: a comprehensive analysis of mechanisms and cutting-edge treatments for color vision deficiency. Front Neurosci 2024; 18:1265630. [PMID: 38298913 PMCID: PMC10828017 DOI: 10.3389/fnins.2024.1265630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024] Open
Abstract
Color blindness is a retinal disease that mainly manifests as a color vision disorder, characterized by achromatopsia, red-green color blindness, and blue-yellow color blindness. With the development of technology and progress in theory, extensive research has been conducted on the genetic basis of color blindness, and various approaches have been explored for its treatment. This article aims to provide a comprehensive review of recent advances in understanding the pathological mechanism, clinical symptoms, and treatment options for color blindness. Additionally, we discuss the various treatment approaches that have been developed to address color blindness, including gene therapy, pharmacological interventions, and visual aids. Furthermore, we highlight the promising results from clinical trials of these treatments, as well as the ongoing challenges that must be addressed to achieve effective and long-lasting therapeutic outcomes. Overall, this review provides valuable insights into the current state of research on color blindness, with the intention of informing further investigation and development of effective treatments for this disease.
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Affiliation(s)
- Zihao Yang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Lin Yan
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenliang Zhang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Jia Qi
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenjing An
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
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Hadyniak SE, Hagen JFD, Eldred KC, Brenerman B, Hussey KA, McCoy RC, Sauria MEG, Kuchenbecker JA, Reh T, Glass I, Neitz M, Neitz J, Taylor J, Johnston RJ. Retinoic acid signaling regulates spatiotemporal specification of human green and red cones. PLoS Biol 2024; 22:e3002464. [PMID: 38206904 PMCID: PMC10783767 DOI: 10.1371/journal.pbio.3002464] [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: 02/04/2023] [Accepted: 12/06/2023] [Indexed: 01/13/2024] Open
Abstract
Trichromacy is unique to primates among placental mammals, enabled by blue (short/S), green (medium/M), and red (long/L) cones. In humans, great apes, and Old World monkeys, cones make a poorly understood choice between M and L cone subtype fates. To determine mechanisms specifying M and L cones, we developed an approach to visualize expression of the highly similar M- and L-opsin mRNAs. M-opsin was observed before L-opsin expression during early human eye development, suggesting that M cones are generated before L cones. In adult human tissue, the early-developing central retina contained a mix of M and L cones compared to the late-developing peripheral region, which contained a high proportion of L cones. Retinoic acid (RA)-synthesizing enzymes are highly expressed early in retinal development. High RA signaling early was sufficient to promote M cone fate and suppress L cone fate in retinal organoids. Across a human population sample, natural variation in the ratios of M and L cone subtypes was associated with a noncoding polymorphism in the NR2F2 gene, a mediator of RA signaling. Our data suggest that RA promotes M cone fate early in development to generate the pattern of M and L cones across the human retina.
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Affiliation(s)
- Sarah E. Hadyniak
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
| | - Joanna F. D. Hagen
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
| | - Kiara C. Eldred
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
- Department of Biological Structure, University of Washington, Seattle, Washington State, United States
| | - Boris Brenerman
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
| | - Katarzyna A. Hussey
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
| | - Rajiv C. McCoy
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
| | - Michael E. G. Sauria
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
| | - James A. Kuchenbecker
- Department of Ophthalmology, University of Washington, Seattle, Washington State, United States
| | - Thomas Reh
- Department of Biological Structure, University of Washington, Seattle, Washington State, United States
| | - Ian Glass
- Department of Biological Structure, University of Washington, Seattle, Washington State, United States
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington State, United States
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington State, United States
| | - James Taylor
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
| | - Robert J. Johnston
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States
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Sechrest ER, Chmelik K, Tan WD, Deng WT. Blue cone monochromacy and gene therapy. Vision Res 2023; 208:108221. [PMID: 37001420 PMCID: PMC10182257 DOI: 10.1016/j.visres.2023.108221] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023]
Abstract
Blue cone monochromacy (BCM) is a congenital vision disorder characterized by complete loss or severely reduced long- and middle-wavelength cone function, caused by mutations in the OPN1LW/OPN1MW gene cluster on the X-chromosome. BCM patients typically suffer from poor visual acuity, severely impaired color discrimination, myopia, and nystagmus. In this review, we cover the genetic causes of BCM, clinical features of BCM patients, genetic testing, and clinical outcome measurements for future BCM clinical trials. However, our emphasis is on detailing the animal models for BCM and gene therapy using adeno-associated vectors (AAV). We describe two mouse models resembling the two most common causes of BCM, current progress in proof-of-concept studies to treat BCM with deletion mutations, the challenges we face, and future directions.
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Affiliation(s)
- Emily R Sechrest
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26505, United States
| | - Kathryn Chmelik
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26505, United States; Department of Biochemistry, West Virginia University, Morgantown, WV 26505, United States
| | - Wendy D Tan
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26505, United States
| | - Wen-Tao Deng
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26505, United States; Department of Biochemistry, West Virginia University, Morgantown, WV 26505, United States.
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Wang Y, Sun W, Xiao X, Jiang Y, Ouyang J, Wang J, Yi Z, Li S, Jia X, Wang P, Hejtmancik JF, Zhang Q. Unique Haplotypes in OPN1LW as a Common Cause of High Myopia With or Without Protanopia: A Potential Window Into Myopic Mechanism. Invest Ophthalmol Vis Sci 2023; 64:29. [PMID: 37097228 PMCID: PMC10148663 DOI: 10.1167/iovs.64.4.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Purpose Specific haplotypes (LVAVA, LIVVA, and LIAVA) formed by five polymorphisms (p.L153M, p.V171I, p.A174V, p.I178V, and p.S180A in exon 3 of OPN1LW) that cause partial or complete exon skipping have been reported as unique genetic causes of high myopia with or without colorblindness. This study aimed to identify the contribution of OPN1LW to early-onset high myopia (eoHM) and the molecular basis underlying eoHM with or without colorblindness. Methods Comparative analysis of exome sequencing data was conducted for 1226 families with eoHM and 9304 families with other eye conditions. OPN1LW variants detected by targeted or whole exome sequencing were confirmed by long-range amplification and Sanger sequencing, together with segregation analysis. The clinical data were thoroughly analyzed. Results Unique haplotypes and truncation variants in OPN1LW were detected exclusively in 68 of 1226 families with eoHM but in none of the 9304 families with other visual diseases (P = 1.63 × 10-63). Four classes of variants were identified: haplotypes causing partial splicing defects in OPN1LW (LVAVA or LIVVA in 31 families), LVAVA in OPN1LW-OPN1MW hybrid gene (in 3 families), LIAVA in OPN1LW (in 29 families), and truncations in OPN1LW (in 5 families). The first class causes partial loss of red photopigments, whereas the latter three result in complete loss of red photopigments. This is different from the replacement of red with green owing to unequal re-arrangement causing red-green colorblindness alone. Of the 68 families, 42 affected male patients (31 families) with the first class of variants (LVAVA or LIVVA in OPN1LW) had eoHM alone, whereas 37 male patients with the latter 3 classes had eoHM with protanopia. Adaptive optics retinal imaging demonstrated reduced cone regularity and density in men with eoHM caused by OPN1LW variants compared to those patients with eoHM and without OPN1LW variants. Conclusion Based on the 68 families with unique variants in OPN1LW, our study provides firm evidence that the two different phenotypes (eoHM with or without colorblindness) are caused by two different classes of variants (partial splicing-effect haplotypes or complete splicing-effect haplotypes/truncation variants, respectively). The contribution of OPN1LW to eoHM (isolated and syndromic) was characterized by OPN1LW variants found in 5.5% (68/1226) of the eoHM families, making it the second most common cause of monogenic eoHM alone (2.4%) and a frequent cause of syndromic monogenic eoHM with colorblindness. Such haplotypes, in which each individual variant alone is considered a benign polymorphism, are potential candidates for other hereditary diseases with causes of missing genetic defects.
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Affiliation(s)
- Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jiamin Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Junwen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Zhen Yi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - J Fielding Hejtmancik
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Rockville, Maryland, United States
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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Mascio AA, Roman AJ, Cideciyan AV, Sheplock R, Wu V, Garafalo AV, Sumaroka A, Pirkle S, Kohl S, Wissinger B, Jacobson SG, Barbur JL. Color Vision in Blue Cone Monochromacy: Outcome Measures for a Clinical Trial. Transl Vis Sci Technol 2023; 12:25. [PMID: 36692456 PMCID: PMC9896867 DOI: 10.1167/tvst.12.1.25] [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] [Indexed: 01/25/2023] Open
Abstract
Purpose Blue cone monochromacy (BCM) is an X-linked retinopathy due to mutations in the OPN1LW/OPN1MW gene cluster. Symptoms include reduced visual acuity and disturbed color vision. We studied BCM color vision to determine outcome measures for future clinical trials. Methods Patients with BCM and normal-vision participants were examined with Farnsworth-Munsell (FM) arrangement tests and the Color Assessment and Diagnosis (CAD) test. A retrospective case series in 36 patients with BCM (ages 6-70) was performed with the FM D-15 test. A subset of six patients also had Roth-28 Hue and CAD tests. Results All patients with BCM had abnormal results for D-15, Roth-28, and CAD tests. With D-15, there was protan-deutan confusion and no bimodal tendency. Roth-28 results reinforced that finding. There was symmetry in color vision metrics between the two eyes and coherence between sessions with the arrangement tests and CAD. Severe abnormalities in red-green sensitivity with CAD were expected. Unexpected were different levels of yellow-blue results with two patterns of abnormal thresholds: moderate elevation in two younger patients and severe elevation in four patients ≥35 years. Coefficients of repeatability and intersession means were tabulated for all test modalities. Conclusions Given understanding of advantages, disadvantages, and complexities of interpretation of results, both an arrangement test and CAD should be useful monitors of color vision through a clinical trial in BCM. Translational Relevance Our pilot studies in BCM of arrangement and CAD tests indicated both were clinically feasible and interpretable in the context of this cone gene disease.
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Affiliation(s)
- Abraham A. Mascio
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Vivian Wu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Alexandra V. Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Sydney Pirkle
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - John L. Barbur
- Centre for Applied Vision Research, School of Health Sciences, City, University of London, London, UK
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Liu H, Lu A, Kelley KA, Forrest D. Noncoding Mutations in a Thyroid Hormone Receptor Gene That Impair Cone Photoreceptor Function. Endocrinology 2023; 164:6984996. [PMID: 36631163 PMCID: PMC10091487 DOI: 10.1210/endocr/bqad006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 01/04/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023]
Abstract
The function of a hormone receptor requires mechanisms to control precisely where, when, and at what level the receptor gene is expressed. An intriguing case concerns the selective induction of thyroid hormone receptor β2 (TRβ2), encoded by Thrb, in the pituitary and also in cone photoreceptors, in which it critically regulates expression of the opsin photopigments that mediate color vision. Here, we investigate the physiological significance of a candidate enhancer for induction of TRβ2 by mutagenesis of a conserved intron region in its natural context in the endogenous Thrb gene in mice. Mutation of e-box sites for bHLH (basic-helix-loop-helix) transcription factors preferentially impairs TRβ2 expression in cones whereas mutation of nearby sequences preferentially impairs expression in pituitary. A deletion encompassing all sites impairs expression in both tissues, indicating bifunctional activity. In cones, the e-box mutations disrupt chromatin acetylation, blunt the developmental induction of TRβ2, and ultimately impair cone opsin expression and sensitivity to longer wavelengths of light. These results demonstrate the necessity of studying an enhancer in its natural chromosomal context for defining biological relevance and reveal surprisingly critical nuances of level and timing of enhancer function. Our findings illustrate the influence of noncoding sequences over thyroid hormone functions.
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Affiliation(s)
- Hong Liu
- NIDDK, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ailing Lu
- NIDDK, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kevin A Kelley
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Douglas Forrest
- NIDDK, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, MD 20892, USA
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Haer-Wigman L, den Ouden A, van Genderen MM, Kroes HY, Verheij J, Smailhodzic D, Hoekstra AS, Vijzelaar R, Blom J, Derks R, Tjon-Pon-Fong M, Yntema HG, Nelen MR, Vissers LELM, Lugtenberg D, Neveling K. Diagnostic analysis of the highly complex OPN1LW/OPN1MW gene cluster using long-read sequencing and MLPA. NPJ Genom Med 2022; 7:65. [PMID: 36351915 PMCID: PMC9646815 DOI: 10.1038/s41525-022-00334-9] [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: 02/25/2022] [Accepted: 10/14/2022] [Indexed: 11/10/2022] Open
Abstract
Pathogenic variants in the OPN1LW/OPN1MW gene cluster are causal for a range of mild to severe visual impairments with color deficiencies. The widely utilized short-read next-generation sequencing (NGS) is inappropriate for the analysis of the OPN1LW/OPN1MW gene cluster and many patients with pathogenic variants stay underdiagnosed. A diagnostic genetic assay was developed for the OPN1LW/OPN1MW gene cluster, consisting of copy number analysis via multiplex ligation-dependent probe amplification and sequence analysis via long-read circular consensus sequencing. Performance was determined on 50 clinical samples referred for genetic confirmation of the clinical diagnosis (n = 43) or carrier status analysis (n = 7). A broad range of pathogenic haplotypes were detected, including deletions, hybrid genes, single variants and combinations of variants. The developed genetic assay for the OPN1LW/OPN1MW gene cluster is a diagnostic test that can detect both structural and nucleotide variants with a straightforward analysis, improving diagnostic care of patients with visual impairment.
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Affiliation(s)
- Lonneke Haer-Wigman
- 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.
| | - Amber den Ouden
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maria M van Genderen
- Bartiméus Diagnostic Center for complex visual disorders, Zeist, The Netherlands
- Department of Ophthalmology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Hester Y Kroes
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Joke Verheij
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Dzenita Smailhodzic
- Bartiméus Diagnostic Center for complex visual disorders, Zeist, The Netherlands
- The Rotterdam Eye Hospital, Rotterdam, 3011 BH, The Netherlands
| | | | | | - Jan Blom
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronny Derks
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Menno Tjon-Pon-Fong
- 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
| | - Helger G Yntema
- 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
| | - Marcel R Nelen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lisenka E L M Vissers
- 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
| | - Dorien Lugtenberg
- 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
| | - Kornelia Neveling
- 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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10
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Patterson EJ, Kalitzeos A, Kane TM, Singh N, Kreis J, Pennesi ME, Hardcastle AJ, Neitz J, Neitz M, Michaelides M, Carroll J. Foveal Cone Structure in Patients With Blue Cone Monochromacy. Invest Ophthalmol Vis Sci 2022; 63:23. [PMID: 36301530 PMCID: PMC9624264 DOI: 10.1167/iovs.63.11.23] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 09/22/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose Blue cone monochromacy (BCM) is a rare inherited cone disorder in which both long- (L-) and middle- (M-) wavelength sensitive cone classes are either impaired or nonfunctional. Assessing genotype-phenotype relationships in BCM can improve our understanding of retinal development in the absence of functional L- and M-cones. Here we examined foveal cone structure in patients with genetically-confirmed BCM, using adaptive optics scanning light ophthalmoscopy (AOSLO). Methods Twenty-three male patients (aged 6-75 years) with genetically-confirmed BCM were recruited for high-resolution imaging. Eight patients had a deletion of the locus control region (LCR), and 15 had a missense mutation-Cys203Arg-affecting the first two genes in the opsin gene array. Foveal cone structure was assessed using confocal and non-confocal split-detection AOSLO across a 300 × 300 µm area, centered on the location of peak cell density. Results Only one of eight patients with LCR deletions and 10 of 15 patients with Cys203Arg mutations had analyzable images. Mean total cone density for Cys203Arg patients was 16,664 ± 11,513 cones/mm2 (n = 10), which is, on average, around 40% of normal. Waveguiding cone density was 2073 ± 963 cones/mm2 (n = 9), which was consistent with published histological estimates of S-cone density in the normal eye. The one patient with an LCR deletion had a total cone density of 10,246 cones/mm2 and waveguiding density of 1535 cones/mm2. Conclusions Our results show that BCM patients with LCR deletions and Cys203Arg mutations have a population of non-waveguiding photoreceptors, although the spectral identity and level of function remain unknown.
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Affiliation(s)
- Emily J. Patterson
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Thomas M. Kane
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Navjit Singh
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Joseph Kreis
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Mark E. Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Alison J. Hardcastle
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Jay Neitz
- Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Maureen Neitz
- Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Joseph Carroll
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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11
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The landscape of submicroscopic structural variants at the OPN1LW/OPN1MW gene cluster on Xq28 underlying blue cone monochromacy. Proc Natl Acad Sci U S A 2022; 119:e2115538119. [PMID: 35759666 PMCID: PMC9271157 DOI: 10.1073/pnas.2115538119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Blue cone monochromacy (BCM) is an X-linked retinal disorder characterized by low vision, photoaversion, and poor color discrimination. BCM is due to the lack of long-wavelength-sensitive and middle-wavelength-sensitive cone photoreceptor function and caused by mutations in the OPN1LW/OPN1MW gene cluster on Xq28. Here, we investigated the prevalence and the landscape of submicroscopic structural variants (SVs) at single-base resolution in BCM patients. We found that about one-third (n = 73) of the 213 molecularly confirmed BCM families carry an SV, most commonly deletions restricted to the OPN1LW/OPN1MW gene cluster. The structure and precise breakpoints of the SVs were resolved in all but one of the 73 families. Twenty-two families-all from the United States-showed the same SV, and we confirmed a common ancestry of this mutation. In total, 42 distinct SVs were identified, including 40 previously unreported SVs, thereby quadrupling the number of precisely mapped SVs underlying BCM. Notably, there was no "region of overlap" among these SVs. However, 90% of SVs encompass the upstream locus control region, an essential enhancer element. Its minimal functional extent based on deletion mapping in patients was refined to 358 bp. Breakpoint analyses suggest diverse mechanisms underlying SV formation as well as in one case the gene conversion-based exchange of a 142-bp deletion between opsin genes. Using parsimonious assumptions, we reconstructed the composition and copy number of the OPN1LW/OPN1MW gene cluster prior to the mutation event and found evidence that large gene arrays may be predisposed to the occurrence of SVs at this locus.
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12
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Stingl K, Baumann B, De Angeli P, Vincent A, Héon E, Cordonnier M, De Baere E, Raskin S, Sato MT, Shiokawa N, Kohl S, Wissinger B. Novel OPN1LW/OPN1MW Exon 3 Haplotype-Associated Splicing Defect in Patients with X-Linked Cone Dysfunction. Int J Mol Sci 2022; 23:ijms23126868. [PMID: 35743313 PMCID: PMC9224739 DOI: 10.3390/ijms23126868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 06/15/2022] [Indexed: 02/01/2023] Open
Abstract
Certain combinations of common variants in exon 3 of OPN1LW and OPN1MW, the genes encoding the apo-protein of the long- and middle-wavelength sensitive cone photoreceptor visual pigments in humans, induce splicing defects and have been associated with dyschromatopsia and cone dysfunction syndromes. Here we report the identification of a novel exon 3 haplotype, G-C-G-A-T-T-G-G (referring to nucleotide variants at cDNA positions c.453, c.457, c.465, c.511, c.513, c.521, c.532, and c.538) deduced to encode a pigment with the amino acid residues L-I-V-V-A at positions p.153, p.171, p.174, p.178, and p.180, in OPN1LW or OPN1MW or both in a series of seven patients from four families with cone dysfunction. Applying minigene assays for all observed exon 3 haplotypes in the patients, we demonstrated that the novel exon 3 haplotype L-I-V-V-A induces a strong but incomplete splicing defect with 3-5% of residual correctly spliced transcripts. Minigene splicing outcomes were similar in HEK293 cells and the human retinoblastoma cell line WERI-Rb1, the latter retaining a cone photoreceptor expression profile including endogenous OPN1LW and OPN1MW gene expression. Patients carrying the novel L-I-V-V-A haplotype presented with a mild form of Blue Cone Monochromacy or Bornholm Eye Disease-like phenotype with reduced visual acuity, reduced cone electroretinography responses, red-green color vision defects, and frequently with severe myopia.
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Affiliation(s)
- Katarina Stingl
- Centre for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany;
| | - Britta Baumann
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
| | - Pietro De Angeli
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children and University of Toronto, Toronto, ON M5G 1X8, Canada; (A.V.); (E.H.)
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children and University of Toronto, Toronto, ON M5G 1X8, Canada; (A.V.); (E.H.)
| | - Monique Cordonnier
- Department of Ophthalmology, Hôpital Erasme, Cliniques Universitaires de Bruxelles, Université Libre de Bruxelles, 1070 Bruxelles, Belgium;
| | - Elfriede De Baere
- Center for Medical Genetics, Ghent University Hospital, Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium;
| | - Salmo Raskin
- Laboratório Genetika, Curitiba 80730-180, Brazil;
| | - Mario Teruo Sato
- Department of Ophthalmology & Otorhinolaryngology, Federal University of Paraná, Curitiba 80060-900, Brazil;
- Retina and Vitreo Consulting Eye Clinic, Curitiba 80530-010, Brazil;
| | - Naoye Shiokawa
- Retina and Vitreo Consulting Eye Clinic, Curitiba 80530-010, Brazil;
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
- Correspondence:
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13
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Hussey KA, Hadyniak SE, Johnston RJ. Patterning and Development of Photoreceptors in the Human Retina. Front Cell Dev Biol 2022; 10:878350. [PMID: 35493094 PMCID: PMC9049932 DOI: 10.3389/fcell.2022.878350] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/25/2022] [Indexed: 01/04/2023] Open
Abstract
Humans rely on visual cues to navigate the world around them. Vision begins with the detection of light by photoreceptor cells in the retina, a light-sensitive tissue located at the back of the eye. Photoreceptor types are defined by morphology, gene expression, light sensitivity, and function. Rod photoreceptors function in low-light vision and motion detection, and cone photoreceptors are responsible for high-acuity daytime and trichromatic color vision. In this review, we discuss the generation, development, and patterning of photoreceptors in the human retina. We describe our current understanding of how photoreceptors are patterned in concentric regions. We conclude with insights into mechanisms of photoreceptor differentiation drawn from studies of model organisms and human retinal organoids.
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14
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VandenBosch LS, Luu K, Timms AE, Challam S, Wu Y, Lee AY, Cherry TJ. Machine Learning Prediction of Non-Coding Variant Impact in Human Retinal cis-Regulatory Elements. Transl Vis Sci Technol 2022; 11:16. [PMID: 35435921 PMCID: PMC9034719 DOI: 10.1167/tvst.11.4.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 03/25/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose Prior studies have demonstrated the significance of specific cis-regulatory variants in retinal disease; however, determining the functional impact of regulatory variants remains a major challenge. In this study, we utilized a machine learning approach, trained on epigenomic data from the adult human retina, to systematically quantify the predicted impact of cis-regulatory variants. Methods We used human retinal DNA accessibility data (ATAC-seq) to determine a set of 18.9k high-confidence, putative cis-regulatory elements. Eighty percent of these elements were used to train a machine learning model utilizing a gapped k-mer support vector machine-based approach. In silico saturation mutagenesis and variant scoring was applied to predict the functional impact of all potential single nucleotide variants within cis-regulatory elements. Impact scores were tested in a 20% hold-out dataset and compared to allele population frequency, phylogenetic conservation, transcription factor (TF) binding motifs, and existing massively parallel reporter assay data. Results We generated a model that distinguishes between human retinal regulatory elements and negative test sequences with 95% accuracy. Among a hold-out test set of 3.7k human retinal CREs, all possible single nucleotide variants were scored. Variants with negative impact scores correlated with higher phylogenetic conservation of the reference allele, disruption of predicted TF binding motifs, and massively parallel reporter expression. Conclusions We demonstrated the utility of human retinal epigenomic data to train a machine learning model for the purpose of predicting the impact of non-coding regulatory sequence variants. Our model accurately scored sequences and predicted putative transcription factor binding motifs. This approach has the potential to expedite the characterization of pathogenic non-coding sequence variants in the context of unexplained retinal disease. Translational Relevance This workflow and resulting dataset serve as a promising genomic tool to facilitate the clinical prioritization of functionally disruptive non-coding mutations in the retina.
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Affiliation(s)
- Leah S. VandenBosch
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kelsey Luu
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Andrew E. Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Shriya Challam
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Yue Wu
- University of Washington Department of Ophthalmology, Seattle, WA, USA
| | - Aaron Y. Lee
- University of Washington Department of Ophthalmology, Seattle, WA, USA
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA
| | - Timothy J. Cherry
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA
- University of Washington Department of Pediatrics, Seattle, WA, USA
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15
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Thomas ED, Timms AE, Giles S, Harkins-Perry S, Lyu P, Hoang T, Qian J, Jackson VE, Bahlo M, Blackshaw S, Friedlander M, Eade K, Cherry TJ. Cell-specific cis-regulatory elements and mechanisms of non-coding genetic disease in human retina and retinal organoids. Dev Cell 2022; 57:820-836.e6. [PMID: 35303433 PMCID: PMC9126240 DOI: 10.1016/j.devcel.2022.02.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 12/06/2021] [Accepted: 02/18/2022] [Indexed: 01/05/2023]
Abstract
Cis-regulatory elements (CREs) play a critical role in the development and disease-states of all human cell types. In the retina, CREs have been implicated in several inherited disorders. To better characterize human retinal CREs, we performed single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq) and single-nucleus RNA sequencing (snRNA-seq) on the developing and adult human retina and on induced pluripotent stem cell (iPSC)-derived retinal organoids. These analyses identified developmentally dynamic, cell-class-specific CREs, enriched transcription-factor-binding motifs, and putative target genes. CREs in the retina and organoids are highly correlated at the single-cell level, and this supports the use of organoids as a model for studying disease-associated CREs. As a proof of concept, we disrupted a disease-associated CRE at 5q14.3, confirming its principal target gene as the miR-9-2 primary transcript and demonstrating its role in neurogenesis and gene regulation in mature glia. This study provides a resource for characterizing human retinal CREs and showcases organoids as a model to study the function of CREs that influence development and disease.
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Affiliation(s)
- Eric D Thomas
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Andrew E Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Sarah Giles
- Lowy Medical Research Institute, La Jolla, CA 92037, USA; Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sarah Harkins-Perry
- Lowy Medical Research Institute, La Jolla, CA 92037, USA; Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Pin Lyu
- Department of Ophthalmology, Wilmer Eye Institute Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thanh Hoang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiang Qian
- Department of Ophthalmology, Wilmer Eye Institute Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Victoria E Jackson
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3052, VIC, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3052, VIC, Australia
| | - Seth Blackshaw
- Department of Ophthalmology, Wilmer Eye Institute Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Martin Friedlander
- Lowy Medical Research Institute, La Jolla, CA 92037, USA; Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kevin Eade
- Lowy Medical Research Institute, La Jolla, CA 92037, USA; Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Timothy J Cherry
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98195, USA; Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98195, USA; Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98195, USA; Brotman Baty Institute, Seattle, WA 98195, USA.
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16
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Mustafi D, Hisama FM, Huey J, Chao JR. The current state of genetic testing platforms for inherited retinal diseases. Ophthalmol Retina 2022; 6:702-710. [PMID: 35307606 PMCID: PMC9356993 DOI: 10.1016/j.oret.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/08/2022] [Accepted: 03/14/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE To evaluate genetic testing platforms used to aid in the diagnosis of inherited retinal degenerations (IRDs). DESIGN Evaluation of diagnostic test or technology SUBJECTS: Targeted genetic panel testing for IRDs METHODS, INTERVENTION, OR TESTING: Data collected regarding targeted genetic panel testing for IRDs offered by different labs were investigated for inclusion of coding and non-coding variants in disease genes. Both large IRD panels and smaller, more focused disease specific panels were included in the analysis. MAIN OUTCOME MEASURES Number of disease genes tested as well as the commonality and uniqueness across testing platforms in both coding and non-coding variants of disease. RESULTS Across the three IRD panel tests investigated, 409 unique genes are represented, of which 269 genes are tested by all three panels. The top 20 genes known to cause over 70% of all IRDs are represented in the 269 common genes tested by all three panels. In addition, 138 non-coding variants are assayed across the three platforms in 50 unique genes. Focused disease specific panels exhibited significant variability across 5 testing platforms that were studied. CONCLUSIONS Ordering genetic testing for IRDs is not straightforward, as evidenced by the multitude of panels available to providers. It is important that there is coverage of both coding and non-coding regions in IRD genes to offer a diagnosis in these patients. This paper details the diversity of testing platforms currently available to clinicians and provides a thorough explanation of genes tested in the different IRD panels. In a time of increased importance for clinical genetic testing of IRD patients, knowledge of the proper test to order is paramount.
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Affiliation(s)
- Debarshi Mustafi
- Department of Ophthalmology, University of Washington, Seattle, Washington; Department of Ophthalmology, Seattle Children's Hospital, Seattle, Washington.
| | - Fuki M Hisama
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington
| | - Jennifer Huey
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
| | - Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, Washington
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17
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Deng WT, Ma X, Sechrest E, Fajardo D, Zhu P, Dyka FM, Wang Y, Lobanova E, Boye S, Baehr W. Gene Therapy in Opn1mw-/-/Opn1sw-/- Mice and Implications for Blue Cone Monochromacy Patients with Deletion Mutations. Hum Gene Ther 2022; 33:708-718. [PMID: 35272502 PMCID: PMC9347391 DOI: 10.1089/hum.2021.298] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Blue cone monochromacy (BCM) is a congenital vision disorder affecting both middle- wavelength (M) and long-wavelength (L) cone photoreceptors of the human retina. BCM results from abolished expression of green and red light-sensitive visual pigments expressed in M- and L-cones, respectively. Previously, we showed that gene augmentation therapy to deliver either human L- or M-opsin rescues dorsal M-opsin dominant cone photoreceptors structurally and functionally in treated M-opsin knockout (Opn1mw-/-) mice. Although Opn1mw-/- mice represent a disease model for BCM patients with deletion mutations, at the cellular level dorsal cones of Opn1mw-/- mice still express low levels of S-opsin which are different from L- and M-cones of BCM patients carrying a congenital opsin deletion. To determine whether BCM cones lacking complete opsin expression from birth would benefit from AAV-mediated gene therapy, we evaluated the outcome of gene therapy, and determined the therapeutic window and longevity of rescue in a mouse model lacking both M- and S- opsin (Opn1mw-/-/Opn1sw-/-). Our data show that cones of Opn1mw-/-/Opn1sw-/- mice are viable at younger ages but undergo rapid degeneration. AAV-mediated expression of human L-opsin promoted cone outer segment regeneration and rescued cone-mediated function when mice were injected subretinally at 2 months of age or younger. Cone-mediated function and visually guided behavior were maintained for at least 8 months post-treatment. However, when mice were treated at 5 and 7 months of age, the chance and effectiveness of rescue was significantly reduced, though cones were still present in the retina. Crossing Opn1mw-/-/Opn1sw-/- mice with proteasomal activity reporter mice (UbG76V-GFP) did not reveal GFP accumulation in Opn1mw-/-/Opn1sw-/- cones eliminating impaired degradation of ubiquitinated proteins as stress factor contributing to cone loss. Our results demonstrate that AAV-mediated gene augmentation therapy can rescue cone structure and function in a mouse model with a congenital opsin deletion, but also emphasize the importance that early intervention is crucial for successful therapy. .
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Affiliation(s)
- Wen-Tao Deng
- West Virginia University, 5631, Ophthalmology, 108 Medical Rd, Morgantown, West Virginia, United States, 26506-6201.,West Virginia University, 5631, Biochemistry, Morgantown, United States, 26506-6201;
| | - Xiajie Ma
- University of Florida, 3463, Gainesville, Florida, United States;
| | - Emily Sechrest
- West Virginia University, 5631, Morgantown, West Virginia, United States;
| | - Diego Fajardo
- University of Florida , Ophthalmology, Gainesville, Florida, United States;
| | - Ping Zhu
- University of Florida, Ophthalmology, ARB RG-240, 1600 SW Archer road, Gainesville, Florida, United States, 32610.,University of Florida, Ophthalmology Department, 1600 SW Archer Rd, Gainesville, Florida, United States, 32610;
| | - Frank M Dyka
- University of Florida, Ophthalmology, ARB R1-236, 1600 SW Archer Road, Gainesville, Florida, United States, 32610;
| | - Yixiao Wang
- University of Florida, 3463, Ophthalmology, Gainesville, Florida, United States;
| | - Ekaterina Lobanova
- University of Florida, 3463, Ophthalmology, Gainesville, Florida, United States;
| | - Shannon Boye
- University of Florida , PO Box 100284, Gainesville, Florida, United States, 32606;
| | - Wolfgang Baehr
- University of Utah Health Science Center, Ophthalmology, 65 Mario Capecchi Dr., Moran Eye Center, Salt Lake City, Utah, United States, 84132;
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18
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Farrell CM, Goldfarb T, Rangwala SH, Astashyn A, Ermolaeva OD, Hem V, Katz KS, Kodali VK, Ludwig F, Wallin CL, Pruitt KD, Murphy TD. RefSeq Functional Elements as experimentally assayed nongenic reference standards and functional interactions in human and mouse. Genome Res 2021; 32:175-188. [PMID: 34876495 PMCID: PMC8744684 DOI: 10.1101/gr.275819.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 12/02/2021] [Indexed: 11/25/2022]
Abstract
Eukaryotic genomes contain many nongenic elements that function in gene regulation, chromosome organization, recombination, repair, or replication, and mutation of those elements can affect genome function and cause disease. Although numerous epigenomic studies provide high coverage of gene regulatory regions, those data are not usually exposed in traditional genome annotation and can be difficult to access and interpret without field-specific expertise. The National Center for Biotechnology Information (NCBI) therefore provides RefSeq Functional Elements (RefSeqFEs), which represent experimentally validated human and mouse nongenic elements derived from the literature. The curated data set is comprised of richly annotated sequence records, descriptive records in the NCBI Gene database, reference genome feature annotation, and activity-based interactions between nongenic regions, target genes, and each other. The data set provides succinct functional details and transparent experimental evidence, leverages data from multiple experimental sources, is readily accessible and adaptable, and uses a flexible data model. The data have multiple uses for basic functional discovery, bioinformatics studies, genetic variant interpretation; as known positive controls for epigenomic data evaluation; and as reference standards for functional interactions. Comparisons to other gene regulatory data sets show that the RefSeqFE data set includes a wider range of feature types representing more areas of biology, but it is comparatively smaller and subject to data selection biases. RefSeqFEs thus provide an alternative and complementary resource for experimentally assayed functional elements, with future data set growth expected.
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Affiliation(s)
- Catherine M Farrell
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Tamara Goldfarb
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Sanjida H Rangwala
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Alexander Astashyn
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Olga D Ermolaeva
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Vichet Hem
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Kenneth S Katz
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Vamsi K Kodali
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Frank Ludwig
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Craig L Wallin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Kim D Pruitt
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Terence D Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
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Zhu P, Dyka F, Ma X, Yin L, Yu H, Baehr W, Hauswirth WW, Deng WT. Disease mechanisms of X-linked cone dystrophy caused by missense mutations in the red and green cone opsins. FASEB J 2021; 35:e21927. [PMID: 34547123 PMCID: PMC8462070 DOI: 10.1096/fj.202101066r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/12/2021] [Accepted: 08/31/2021] [Indexed: 11/11/2022]
Abstract
Cone photoreceptors are responsible for the visual acuity and color vision of the human eye. Red/green cone opsin missense mutations N94K, W177R, P307L, R330Q, and G338E have been identified in subjects with congenital blue cone monochromacy or color‐vision deficiency. Studies on disease mechanisms due to these cone opsin mutations have been previously carried out exclusively in vitro, and the reported impairments were not always consistent. Here we expressed these mutants via AAV specifically in vivo in M‐opsin knockout mouse cones to investigate their subcellular localization, the pathogenic effects on cone structure, function, and cone viability. We show that these mutations alter the M‐opsin structure, function, and localization. N94K and W177R mutants appeared to be misfolded since they localized exclusively in cone inner segments and endoplasmic reticulum. In contrast, P307L, R330Q, and G338E mutants were detected predominately in cone outer segments. Expression of R330Q and G338E, but not P307L opsins, also partially restored expression and correct localization of cone PDE6α’ and cone transducin γ and resulted in partial rescue of M‐cone‐mediated light responses. Expression of W177R and P307L mutants significantly reduced cone viability, whereas N94K, R330Q, and G338E were only modestly toxic. We propose that although the underlying biochemical and cellular defects caused by these mutants are distinct, they all seem to exhibit a dominant phenotype, resembling autosomal dominant retinitis pigmentosa associated with the majority of rhodopsin missense mutations. The understanding of the molecular mechanisms associated with these cone opsin mutants is fundamental to developing targeted therapies for cone dystrophy/dysfunction.
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Affiliation(s)
- Ping Zhu
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Frank Dyka
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Xiaojie Ma
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Ling Yin
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Heather Yu
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Wolfgang Baehr
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah, USA.,Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, Utah, USA.,Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Wen-Tao Deng
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
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20
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Patterson EJ, Langlo CS, Georgiou M, Kalitzeos A, Pennesi ME, Neitz J, Hardcastle AJ, Neitz M, Michaelides M, Carroll J. Comparing Retinal Structure in Patients with Achromatopsia and Blue Cone Monochromacy Using OCT. OPHTHALMOLOGY SCIENCE 2021; 1:100047. [PMID: 36186895 PMCID: PMC9521040 DOI: 10.1016/j.xops.2021.100047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 07/01/2021] [Accepted: 07/20/2021] [Indexed: 01/12/2023]
Abstract
Purpose To compare foveal hypoplasia and the appearance of the ellipsoid zone (EZ) at the fovea in patients with genetically confirmed achromatopsia (ACHM) and blue cone monochromacy (BCM). Design Retrospective, multi-center observational study. Subjects Molecularly confirmed patients with ACHM (n = 89) and BCM (n = 33). Methods We analyzed high-resolution spectral domain optical coherence tomography (SD-OCT) images of the macula from aforementioned patients with BCM. Three observers independently graded SD-OCT images for foveal hypoplasia (i.e. retention of one or more inner retinal layers at the fovea) and four observers judged the integrity of the EZ at the fovea, based on an established grading scheme. These measures were compared with previously published data from the ACHM patients. Main Outcome Measures Presence of foveal hypoplasia and EZ grade. Results Foveal hypoplasia was significantly more prevalent in ACHM than in BCM (p<0.001). In addition, we observed a significant difference in the distribution of EZ grades between ACHM and BCM, with grade II EZ being by far the most common phenotype in BCM (61% of patients). In contrast, ACHM patients had a relatively equal prevalence of EZ grades I, II, and IV. Interestingly, grade IV EZ was 2.6 times more prevalent in ACHM compared to BCM, while grade V EZ (macular atrophy) was present in 3% of both the ACHM and BCM cohorts. Conclusions The higher incidence of foveal hypoplasia in ACHM than BCM supports a role for cone activity in foveal development. Although there are differences in EZ grades between these conditions, the degree of overlap suggests EZ grade is not sufficient for definitive diagnosis, in contrast to previous reports. Analysis of additional OCT features in similar cohorts may reveal differences with greater diagnostic value. Finally, the extent to which foveal hypoplasia or EZ grade is prognostic for therapeutic potential in either group remains to be seen, but motivates further study.
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Key Words
- achromatopsia
- blue cone monochromacy
- cone
- ellipsoid zone
- fovea
- foveal hypoplasia
- hyper-reflective band
- imaging
- oct
- photoreceptor
- sd-oct
- x-linked cone dysfunction
- achm, achromatopsia
- bcm, blue cone monochromacy
- elm, external limiting membrane
- erg, electroretinography
- ez, ellipsoid zone
- lcr, locus control region
- lrp, longitudinal reflectivity profile
- npv, negative predictive value
- ppv, positive predictive value
- sd-oct, spectral-domain oct
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Affiliation(s)
- Emily J. Patterson
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | | | - Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Mark E. Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Jay Neitz
- Ophthalmology, University of Washington, Seattle, Washington
| | - Alison J. Hardcastle
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Maureen Neitz
- Ophthalmology, University of Washington, Seattle, Washington
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Joseph Carroll
- Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
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21
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Iarossi G, Coppè AM, Passarelli C, Maltese PE, Sinibaldi L, Cappelli A, Cetola S, Novelli A, Buzzonetti L. Blue Cone Monochromatism with Foveal Hypoplasia Caused by the Concomitant Effect of Variants in OPN1LW/OPN1MW and GPR143 Genes. Int J Mol Sci 2021; 22:ijms22168617. [PMID: 34445325 PMCID: PMC8395340 DOI: 10.3390/ijms22168617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 12/11/2022] Open
Abstract
Blue cone monochromatism (BCM) is an X-linked recessive cone dysfunction disorder caused by mutations in the OPN1LW/OPN1MW gene cluster, encoding long (L)- and middle (M)-wavelength-sensitive cone opsins. Here, we report on the unusual clinical presentation of BCM caused by a novel mutation in the OPN1LW gene in a young man. We describe in detail the phenotype of the proband, and the subclinical morpho-functional anomalies shown by his carrier mother. At a clinical level, the extensive functional evaluation demonstrated in the proband the M/L cone affection and the sparing of S-cone function, distinctive findings of BCM. Interestingly, spectral-domain optical coherence tomography showed the presence of foveal hypoplasia with focal irregularities of the ellipsoid layer in the foveal area, reported to be associated with some cases of cone-rod dystrophy and achromatopsia. At a molecular level, we identified the novel mutation c.427T > C p.(Ser143Pro) in the OPN1LW gene and the common missense mutation c.607T > C (p.Cys203Arg) in the OPN1MW gene. In addition, we discovered the c.768-2_769delAGTT splicing variant in the GPR143 gene. To our knowledge, this is the first case of foveal hypoplasia in a BCM patient and of mild clinical affection in a female carrier caused by the concomitant effect of variants in OPN1LW/OPN1MW and GPR143 genes, thus as the result of the simultaneous action of two independent genetic defects.
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Affiliation(s)
- Giancarlo Iarossi
- Department of Ophthalmology, Bambino Gesù Children’s Hospital, 00165 Rome, Italy; (A.M.C.); (A.C.); (L.B.)
- Correspondence: (G.I.); (P.E.M.); Tel.: +39-06-6859-3362 (G.I.); +39-04-6442-0795 (P.E.M.)
| | - Andrea Maria Coppè
- Department of Ophthalmology, Bambino Gesù Children’s Hospital, 00165 Rome, Italy; (A.M.C.); (A.C.); (L.B.)
| | - Chiara Passarelli
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (C.P.); (L.S.); (S.C.); (A.N.)
| | - Paolo Enrico Maltese
- MAGI’S Lab s.r.l., 38068 Rovereto, Italy
- Correspondence: (G.I.); (P.E.M.); Tel.: +39-06-6859-3362 (G.I.); +39-04-6442-0795 (P.E.M.)
| | - Lorenzo Sinibaldi
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (C.P.); (L.S.); (S.C.); (A.N.)
- Rare Disease and Medical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
| | - Alessandro Cappelli
- Department of Ophthalmology, Bambino Gesù Children’s Hospital, 00165 Rome, Italy; (A.M.C.); (A.C.); (L.B.)
| | - Sarah Cetola
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (C.P.); (L.S.); (S.C.); (A.N.)
| | - Antonio Novelli
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (C.P.); (L.S.); (S.C.); (A.N.)
| | - Luca Buzzonetti
- Department of Ophthalmology, Bambino Gesù Children’s Hospital, 00165 Rome, Italy; (A.M.C.); (A.C.); (L.B.)
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22
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Neitz M, Neitz J. Intermixing the OPN1LW and OPN1MW Genes Disrupts the Exonic Splicing Code Causing an Array of Vision Disorders. Genes (Basel) 2021; 12:genes12081180. [PMID: 34440353 PMCID: PMC8391646 DOI: 10.3390/genes12081180] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023] Open
Abstract
Light absorption by photopigment molecules expressed in the photoreceptors in the retina is the first step in seeing. Two types of photoreceptors in the human retina are responsible for image formation: rods, and cones. Except at very low light levels when rods are active, all vision is based on cones. Cones mediate high acuity vision and color vision. Furthermore, they are critically important in the visual feedback mechanism that regulates refractive development of the eye during childhood. The human retina contains a mosaic of three cone types, short-wavelength (S), long-wavelength (L), and middle-wavelength (M) sensitive; however, the vast majority (~94%) are L and M cones. The OPN1LW and OPN1MW genes, located on the X-chromosome at Xq28, encode the protein component of the light-sensitive photopigments expressed in the L and M cones. Diverse haplotypes of exon 3 of the OPN1LW and OPN1MW genes arose thru unequal recombination mechanisms that have intermixed the genes. A subset of the haplotypes causes exon 3- skipping during pre-messenger RNA splicing and are associated with vision disorders. Here, we review the mechanism by which splicing defects in these genes cause vision disorders.
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23
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McNerney C, Johnston RJ. Thyroid hormone signaling specifies cone photoreceptor subtypes during eye development: Insights from model organisms and human stem cell-derived retinal organoids. VITAMINS AND HORMONES 2021; 116:51-90. [PMID: 33752828 DOI: 10.1016/bs.vh.2021.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Cones are the color-detecting photoreceptors of the vertebrate eye. Cones are specialized into subtypes whose functions are determined by the expression of color-sensitive opsin proteins. Organisms differ greatly in the number and patterning of cone subtypes. Despite these differences, thyroid hormone is an important regulator of opsin expression in most vertebrates. In this chapter, we outline how the timing of thyroid hormone signaling controls cone subtype fates during retinal development. We first examine our current understanding of cone subtype specification in model organisms and then describe advances in human stem cell-derived organoid technology that identified mechanisms controlling development of the human retina.
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Affiliation(s)
- Christina McNerney
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States.
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24
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Abstract
Color is a fundamental aspect of normal visual experience. This chapter provides an overview of the role of color in human behavior, a survey of current knowledge regarding the genetic, retinal, and neural mechanisms that enable color vision, and a review of inherited and acquired defects of color vision including a discussion of diagnostic tests.
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Affiliation(s)
- Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, United States.
| | - Bevil R Conway
- Laboratory of Sensorimotor Research, National Eye Institute, National Institute of Mental Health, Bethesda, MD, United States.
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25
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Semenov EP, Sheplock R, Roman AJ, McGuigan DB, Swider M, Cideciyan AV, Jacobson SG. Reading Performance in Blue Cone Monochromacy: Defining an Outcome Measure for a Clinical Trial. Transl Vis Sci Technol 2020; 9:13. [PMID: 33344057 PMCID: PMC7726588 DOI: 10.1167/tvst.9.13.13] [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: 07/20/2020] [Accepted: 10/12/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose Blue cone monochromacy (BCM), a congenital X-linked retinal disease caused by mutations in the OPN1LW/OPN1MW gene cluster, is under consideration for intravitreal gene therapy. Difficulties with near vision tasks experienced by these patients prompted this study of reading performance as a potential outcome measure for a future clinical trial. Methods Clinically and molecularly diagnosed patients with BCM (n = 17; ages 15–63 years) and subjects with normal vision (n = 22; ages 18–72 years) were examined with the MNREAD acuity chart for both uniocular and binocular conditions. Parameters derived from the measurements in patients were compared with normal data and also within the group of patients. Intersession, interocular and between-subject variabilities were determined. The frequent complaint of light sensitivity in BCM was examined by comparing results from black text on a white background (regular polarity) versus white on black (reverse polarity) conditions. Results MNREAD curves of print size versus reading speed were right-shifted compared with normal in all patients with BCM. All parameters in patients with BCM indicated abnormal reading performance. Intersession variability was slightly higher in BCM than in normal, but comparable with results previously reported for other patients with maculopathies. There was a high degree of disease symmetry in reading performance in this BCM cohort. Reverse polarity showed better reading parameters than regular polarity in 82% of the patients. Conclusions MNREAD measures of reading performance in patients with BCM would be a worthy and robust secondary outcome in a clinical trial protocol, given its dual purpose of quantifying macular vision and addressing an important quality of life issue. Translational Relevance Assessment of an outcome for a clinical trial.
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Affiliation(s)
- Evelyn P Semenov
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Alejandro J Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - David B McGuigan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
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26
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Wynne N, Carroll J, Duncan JL. Promises and pitfalls of evaluating photoreceptor-based retinal disease with adaptive optics scanning light ophthalmoscopy (AOSLO). Prog Retin Eye Res 2020; 83:100920. [PMID: 33161127 DOI: 10.1016/j.preteyeres.2020.100920] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 12/15/2022]
Abstract
Adaptive optics scanning light ophthalmoscopy (AOSLO) allows visualization of the living human retina with exquisite single-cell resolution. This technology has improved our understanding of normal retinal structure and revealed pathophysiological details of a number of retinal diseases. Despite the remarkable capabilities of AOSLO, it has not seen the widespread commercial adoption and mainstream clinical success of other modalities developed in a similar time frame. Nevertheless, continued advancements in AOSLO hardware and software have expanded use to a broader range of patients. Current devices enable imaging of a number of different retinal cell types, with recent improvements in stimulus and detection schemes enabling monitoring of retinal function, microscopic structural changes, and even subcellular activity. This has positioned AOSLO for use in clinical trials, primarily as exploratory outcome measures or biomarkers that can be used to monitor disease progression or therapeutic response. AOSLO metrics could facilitate patient selection for such trials, to refine inclusion criteria or to guide the choice of therapy, depending on the presence, absence, or functional viability of specific cell types. Here we explore the potential of AOSLO retinal imaging by reviewing clinical applications as well as some of the pitfalls and barriers to more widespread clinical adoption.
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Affiliation(s)
- Niamh Wynne
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA.
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27
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De Silva SR, Arno G, Robson AG, Fakin A, Pontikos N, Mohamed MD, Bird AC, Moore AT, Michaelides M, Webster AR, Mahroo OA. The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies. Prog Retin Eye Res 2020; 82:100898. [PMID: 32860923 DOI: 10.1016/j.preteyeres.2020.100898] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/07/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research.
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Affiliation(s)
- Samantha R De Silva
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Ana Fakin
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Moin D Mohamed
- Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Alan C Bird
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK; Section of Ophthalmology, King's College London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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28
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Sumaroka A, Cideciyan AV, Sheplock R, Wu V, Kohl S, Wissinger B, Jacobson SG. Foveal Therapy in Blue Cone Monochromacy: Predictions of Visual Potential From Artificial Intelligence. Front Neurosci 2020; 14:800. [PMID: 32848570 PMCID: PMC7416698 DOI: 10.3389/fnins.2020.00800] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/07/2020] [Indexed: 11/13/2022] Open
Abstract
Novel therapeutic approaches for treating inherited retinal degenerations (IRDs) prompt a need to understand which patients with impaired vision have the anatomical potential to gain from participation in a clinical trial. We used supervised machine learning to predict foveal function from foveal structure in blue cone monochromacy (BCM), an X-linked congenital cone photoreceptor dysfunction secondary to mutations in the OPN1LW/OPN1MW gene cluster. BCM patients with either disease-associated large deletion or missense mutations were studied and results compared with those from subjects with other forms of IRD and various degrees of preserved central structure and function. A machine learning technique was used to associate foveal sensitivities and best-corrected visual acuities to foveal structure in IRD patients. Two random forest (RF) models trained on IRD data were applied to predict foveal function in BCM. A curve fitting method was also used and results compared with those of the RF models. The BCM and IRD patients had a comparable range of foveal structure. IRD patients had peak sensitivity at the fovea. Machine learning could successfully predict foveal sensitivity (FS) results from segmented or un-segmented optical coherence tomography (OCT) input. Application of machine learning predictions to BCM at the fovea showed differences between predicted and measured sensitivities, thereby defining treatment potential. The curve fitting method provided similar results. Given a measure of visual acuity (VA) and foveal outer nuclear layer thickness, the question of how many lines of acuity would represent the best efficacious result for each BCM patient could be answered. We propose that foveal vision improvement potential in BCM is predictable from retinal structure using machine learning and curve fitting approaches. This should allow estimates of maximal efficacy in patients being considered for clinical trials and also guide decisions about dosing.
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Affiliation(s)
- Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Vivian Wu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tüebingen, Tüebingen, Germany
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tüebingen, Tüebingen, Germany
| | - Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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29
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Tsujimura T. Mechanistic insights into the evolution of the differential expression of tandemly arrayed cone opsin genes in zebrafish. Dev Growth Differ 2020; 62:465-475. [PMID: 32712957 DOI: 10.1111/dgd.12690] [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: 05/26/2020] [Revised: 07/10/2020] [Accepted: 07/18/2020] [Indexed: 12/21/2022]
Abstract
The genome of many organisms contains several loci consisting of duplicated genes that are arrayed in tandem. The daughter genes produced by duplication typically exhibit differential expression patterns with each other or otherwise experience pseudogenization. Remarkably, opsin genes in fish are preserved after many duplications in different lineages. This fact indicates that fish opsin genes are characterized by a regulatory mechanism that could intrinsically facilitate the differentiation of the expression patterns. However, little is known about the mechanisms that underlie the differential expression patterns or how they were established during evolution. The loci of green (RH2)- and red (LWS)-sensitive cone opsin genes in zebrafish have been used as model systems to study the differential regulation of tandemly arrayed opsin genes. Over a decade of studies have uncovered several mechanistic features that might have assisted the differentiation and preservation of duplicated genes. Furthermore, recent progress in the understanding of the transcriptional process in general has added essential insights. In this article, the current understanding of the transcriptional regulation of differentially expressed tandemly arrayed cone opsin genes in zebrafish is summarized and a possible evolutionary scenario that could achieve this differentiation is discussed.
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Affiliation(s)
- Taro Tsujimura
- Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Japan
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Cherry TJ, Yang MG, Harmin DA, Tao P, Timms AE, Bauwens M, Allikmets R, Jones EM, Chen R, De Baere E, Greenberg ME. Mapping the cis-regulatory architecture of the human retina reveals noncoding genetic variation in disease. Proc Natl Acad Sci U S A 2020; 117:9001-9012. [PMID: 32265282 PMCID: PMC7183164 DOI: 10.1073/pnas.1922501117] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The interplay of transcription factors and cis-regulatory elements (CREs) orchestrates the dynamic and diverse genetic programs that assemble the human central nervous system (CNS) during development and maintain its function throughout life. Genetic variation within CREs plays a central role in phenotypic variation in complex traits including the risk of developing disease. We took advantage of the retina, a well-characterized region of the CNS known to be affected by pathogenic variants in CREs, to establish a roadmap for characterizing regulatory variation in the human CNS. This comprehensive analysis of tissue-specific regulatory elements, transcription factor binding, and gene expression programs in three regions of the human visual system (retina, macula, and retinal pigment epithelium/choroid) reveals features of regulatory element evolution that shape tissue-specific gene expression programs and defines regulatory elements with the potential to contribute to Mendelian and complex disorders of human vision.
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Affiliation(s)
- Timothy J Cherry
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98101;
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98101
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98101
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101
| | - Marty G Yang
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115
| | - David A Harmin
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Peter Tao
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Andrew E Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101
| | - Miriam Bauwens
- Center for Medical Genetics, Ghent University and Ghent University Hospital, 9000 Ghent, Belgium
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, NY 10032
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032
| | - Evan M Jones
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411
| | - Elfride De Baere
- Center for Medical Genetics, Ghent University and Ghent University Hospital, 9000 Ghent, Belgium
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Deng WT, Li J, Zhu P, Freedman B, Smith WC, Baehr W, Hauswirth WW. Rescue of M-cone Function in Aged Opn1mw-/- Mice, a Model for Late-Stage Blue Cone Monochromacy. Invest Ophthalmol Vis Sci 2019; 60:3644-3651. [PMID: 31469404 PMCID: PMC6716949 DOI: 10.1167/iovs.19-27079] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/20/2019] [Indexed: 12/25/2022] Open
Abstract
Purpose Previously we showed that AAV5-mediated expression of either human M- or L-opsin promoted regrowth of cone outer segments and rescued M-cone function in the treated M-opsin knockout (Opn1mw-/-) dorsal retina. In this study, we determined cone viability and window of treatability in aged Opn1mw-/- mice. Methods Cone viability was assessed with antibody against cone arrestin and peanut agglutinin (PNA) staining. The rate of cone degeneration in Opn1mw-/- mice was quantified by PNA staining. AAV5 vector expressing human L-opsin was injected subretinally into one eye of Opn1mw-/- mice at 1, 7, and 15 months old, while the contralateral eyes served as controls. M-cone-mediated retinal function was analyzed 2 and 13 months postinjection by full-field ERG. L-opsin transgene expression and cone outer segment structure were examined by immunohistochemistry. Results We showed that dorsal M-opsin dominant cones exhibit outer segment degeneration at an early age in Opn1mw-/- mice, whereas ventral S-opsin dominant cones were normal. The remaining M-opsin dominant cones remained viable for at least 15 months, albeit having shortened or no outer segments. We also showed that AAV5-mediated expression of human L-opsin was still able to rescue function and outer segment structure in the remaining M-opsin dominant cones when treatment was initiated at 15 months of age. Conclusions Our results showing that the remaining M-opsin dominant cones in aged Opn1mw-/- mice can still be rescued by gene therapy is helpful for establishing the window of treatability in future blue cone monochromacy clinical trials.
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Affiliation(s)
- Wen-Tao Deng
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States
| | - Jie Li
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States
| | - Ping Zhu
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States
| | - Beau Freedman
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States
| | - W. Clay Smith
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States
| | - Wolfgang Baehr
- Department of Ophthalmology, John A. Moran Eye Center, University of Utah Health Science Center, Salt Lake City, Utah, United States
- Department of Neurobiology and Anatomy, University of Utah Health Science Center, Salt Lake City, Utah, United States
- Department of Biology, University of Utah, Salt Lake City, Utah, United States
| | - William W. Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States
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Sumaroka A, Garafalo AV, Cideciyan AV, Charng J, Roman AJ, Choi W, Saxena S, Aksianiuk V, Kohl S, Wissinger B, Jacobson SG. Blue Cone Monochromacy Caused by the C203R Missense Mutation or Large Deletion Mutations. Invest Ophthalmol Vis Sci 2019; 59:5762-5772. [PMID: 30516820 DOI: 10.1167/iovs.18-25280] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To compare the phenotype of blue cone monochromacy (BCM) caused by large deletion mutations with those having the C203R missense mutation. Methods BCM patients with large deletion mutations (n = 21; age range, 5-60 years), and with the C203R missense mutation (n = 13; age range, 5-70 years), were studied with optical coherence tomography, visual acuity, and perimetric sensitivity in a retrospective observational case series. Perceptual estimates of spatial resolution driven by rods, S-cones, and L/M-cones were obtained by the choice of chromatic gratings presented on varied adapting conditions with a modified microperimeter. Results Both genotypes had abnormal foveal photoreceptor structure early in life. Patients with the C203R mutation, however, had decades-longer persistence of foveal photoreceptor outer nuclear layer thickness and a slower rate of development of inner segment/outer segment defects than did patients with large deletion mutations. At late ages, both genotypes had comparably severe losses of central structure. At the rod-rich hot spot, there was no difference in structure between cohorts with age. Grating acuities in all BCM patients were driven by S-cones and rods; the foveal structural differences were not reflected in a difference between cohorts in visual sensitivity and spatial resolution. Conclusions A difference in structural phenotype due to the C203R mutation versus large deletion mutations in BCM was detected as a more prolonged persistence of foveal photoreceptor structure in patients with the missense mutation. This should be taken into account in planning natural history studies, selecting outcomes for clinical trials, and defining the time window for possible therapies.
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Affiliation(s)
- Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alexandra V Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Jason Charng
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alejandro J Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Windy Choi
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Supna Saxena
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Valeryia Aksianiuk
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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Eldred KC, Hadyniak SE, Hussey KA, Brenerman B, Zhang PW, Chamling X, Sluch VM, Welsbie DS, Hattar S, Taylor J, Wahlin K, Zack DJ, Johnston RJ. Thyroid hormone signaling specifies cone subtypes in human retinal organoids. Science 2018; 362:362/6411/eaau6348. [PMID: 30309916 PMCID: PMC6249681 DOI: 10.1126/science.aau6348] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 08/30/2018] [Indexed: 12/24/2022]
Abstract
INTRODUCTION: Cone photoreceptors in the human retina enable daytime, color, and high-acuity vision. The three subtypes of human cones are defined by the visual pigment that they express: blue-opsin (short wavelength; S), green-opsin (medium wavelength; M), or red-opsin (long wavelength; L). Mutations that affect opsin expression or function cause various forms of color blindness and retinal degeneration. RATIONALE: Our current understanding of the vertebrate eye has been derived primarily from the study of model organisms. We studied the human retina to understand the developmental mechanisms that generate the mosaic of mutually exclusive cone subtypes. Specification of human cones occurs in a two-step process. First, a decision occurs between S versus L/M cone fates. If the L/M fate is chosen, a subsequent choice is made between expression of L- or M-opsin. To determine the mechanism that controls the first decision between S and L/M cone fates, we studied human retinal organoids derived from stem cells. RESULTS: We found that human organoids and retinas have similar distributions, gene expression profiles, and morphologies of cone subtypes. During development, S cones are specified first, followed by L/M cones. This temporal switch from specification of S cones to generation of L/M cones is controlled by thyroid hormone (TH) signaling. In retinal organoids that lacked thyroid hormone receptor β (Thrβ), all cones developed into the S subtype. Thrβ binds with high affinity to triiodothyronine (T3), the more active form of TH, to regulate gene expression. We observed that addition of T3 early during development induced L/M fate in nearly all cones. Thus, TH signaling through Thrβ is necessary and sufficient to induce L/M cone fate and suppress S fate. TH exists largely in two states: thyroxine (T4), the most abundant circulating form of TH, and T3, which binds TH receptors with high affinity. We hypothesized that the retina itself could modulate TH levels to control subtype fates. We found that deiodinase 3 (DIO3), an enzyme that degrades both T3 and T4, was expressed early in organoid and retina development. Conversely, deiodinase 2 (DIO2), an enzyme that converts T4 to active T3, as well as TH carriers and transporters, were expressed later in development. Temporally dynamic expression of TH-degrading and -activating proteins supports a model in which the retina itself controls TH levels, ensuring low TH signaling early to specify S cones and high TH signaling later in development to produce L/M cones. CONCLUSION: Studies of model organisms and human epidemiology often generate hypotheses about human biology that cannot be studied in humans. Organoids provide a system to determine the mechanisms of human development, enabling direct testing of hypotheses in developing human tissue. Our studies identify temporal regulation of TH signaling as a mechanism that controls cone subtype specification in humans. Consistent with our findings, preterm human infants with low T3 and T4 have an increased incidence of color vision defects. Moreover, our identification of a mechanism that generates one cone subtype while suppressing the other, coupled with successful transplantation and incorporation of stem cell-derived photoreceptors in mice, suggests that the promise of therapies to treat human diseases such as color blindness, retinitis pigmentosa, and macular degeneration will be achieved in the near future. ■ The mechanisms underlying specification of neuronal subtypes within the human nervous system are largely unknown. The blue (S), green (M), and red (L) cones of the retina enable high-acuity daytime and color vision. To determine the mechanism that controls S versus L/M fates, we studied the differentiation of human retinal organoids. Organoids and retinas have similar distributions, expression profiles, and morphologies of cone subtypes. S cones are specified first, followed by L/M cones, and thyroid hormone signaling controls this temporal switch. Dynamic expression of thyroid hormone–degrading and –activating proteins within the retina ensures low signaling early to specify S cones and high signaling late to produce L/M cones. This work establishes organoids as a model for determining mechanisms of human development with promising utility for therapeutics and vision repair.
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Affiliation(s)
- Kiara C Eldred
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Sarah E Hadyniak
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Katarzyna A Hussey
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Boris Brenerman
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Ping-Wu Zhang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Xitiz Chamling
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Valentin M Sluch
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Derek S Welsbie
- Shiley Eye Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Samer Hattar
- National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - James Taylor
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA.,Department of Computer Science, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Karl Wahlin
- Shiley Eye Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Donald J Zack
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA.
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Katagiri S, Iwasa M, Hayashi T, Hosono K, Yamashita T, Kuniyoshi K, Ueno S, Kondo M, Ueyama H, Ogita H, Shichida Y, Inagaki H, Kurahashi H, Kondo H, Ohji M, Hotta Y, Nakano T. Genotype determination of the OPN1LW/OPN1MW genes: novel disease-causing mechanisms in Japanese patients with blue cone monochromacy. Sci Rep 2018; 8:11507. [PMID: 30065301 PMCID: PMC6068165 DOI: 10.1038/s41598-018-29891-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/20/2018] [Indexed: 01/26/2023] Open
Abstract
Blue cone monochromacy (BCM) is characterized by loss of function of both OPN1LW (the first) and OPN1MW (the downstream) genes on the X chromosome. The purpose of this study was to investigate the first and downstream genes in the OPN1LW/OPN1MW array in four unrelated Japanese males with BCM. In Case 1, only one gene was present. Abnormalities were found in the promoter, which had a mixed unique profile of first and downstream gene promoters and a -71A > C substitution. As the promoter was active in the reporter assay, the cause of BCM remains unclear. In Case 2, the same novel mutation, M273K, was present in exon 5 of both genes in a two-gene array. The mutant pigments showed no absorbance at any of the wavelengths tested, suggesting that the mutation causes pigment dysfunction. Case 3 had a large deletion including the locus control region and entire first gene. Case 4 also had a large deletion involving exons 2-6 of the first gene. As an intact LCR was present upstream and one apparently normal downstream gene was present, BCM in Case 4 was not ascribed solely to the deletion. The deletions in Cases 3 and 4 were considered to have been caused by non-homologous recombination.
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Affiliation(s)
- Satoshi Katagiri
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Maki Iwasa
- Department of Ophthalmology, Shiga University of Medical Science, Shiga, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.
- Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, Tokyo, Japan.
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Mie, Japan
| | - Hisao Ueyama
- Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Shiga, Japan.
| | - Hisakazu Ogita
- Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Shiga, Japan
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hidehito Inagaki
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan
| | - Hiroki Kurahashi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan
| | - Hiroyuki Kondo
- Department of Ophthalmology, University of Occupational and Environmental Health, Fukuoka, Japan
| | - Masahito Ohji
- Department of Ophthalmology, Shiga University of Medical Science, Shiga, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
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Buena-Atienza E, Nasser F, Kohl S, Wissinger B. A 73,128 bp de novo deletion encompassing the OPN1LW/OPN1MW gene cluster in sporadic Blue Cone Monochromacy: a case report. BMC MEDICAL GENETICS 2018; 19:107. [PMID: 29940872 PMCID: PMC6019650 DOI: 10.1186/s12881-018-0623-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/12/2018] [Indexed: 01/04/2023]
Abstract
Background Blue Cone Monochromacy (BCM) is a rare congenital cone dysfunction disorder with X-linked recessive mode of inheritance. BCM is caused by mutations at the OPN1LW/MW cone opsin gene cluster including deletions of the locus control region (LCR) and/or parts of the gene cluster. We aimed at investigating the clinical presentation, genetic cause and inheritance underlying a sporadic case of BCM. Case presentation We report a 24-year-old male presenting with congenital photophobia, nystagmus and colour vision abnormalities. There was no history of retinal dystrophy in the family. Clinical diagnosis of BCM was supported by genetic investigations of the patient and his family members. Molecular genetic analysis of the OPN1LW/OPN1MW gene cluster revealed a novel deletion of about 73 kb in the patient encompassing the LCR. The deletion was absent in the X-chromosomes of both the mother and transmitting grandfather. Conclusions The present report provides the clinical findings and the genetic basis underlying a sporadic BCM case which is caused by a de novo deletion within the OPN1LW/MW gene cluster originating from the mother’s germline due to Alu-repeat mediated recombination. This is the first report of a de novo deletion resulting in BCM, highlighting the importance to consider BCM and perform genetic testing for this condition in male patients with cone dysfunction also in the absence of a positive family history.
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Affiliation(s)
- Elena Buena-Atienza
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany
| | - Fadi Nasser
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany.
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Maguire J, Parry NRA, Kremers J, Murray IJ, McKeefry D. Human S-cone electroretinograms obtained by silent substitution stimulation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:B11-B18. [PMID: 29603933 DOI: 10.1364/josaa.35.000b11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/27/2017] [Indexed: 06/08/2023]
Abstract
We used triple silent substitution stimuli to characterize human S-cone electroretinograms (ERGs) in normal trichromats. Short-wavelength-cone (S-cone) ERGs were found to have different morphological features and temporal frequency response characteristics compared to ERGs derived from L-cones, M-cones, and rod photoreceptors in normal participants. Furthermore, in two cases of retinal pathology, blue cone monochromatism (BCM) and enhanced S-cone syndrome (ESCS), S-cone ERGs elicited by our stimuli were preserved and enhanced, respectively. The results from both normal and pathological retinae demonstrate that triple silent substitution stimuli can be used to generate ERGs that provide an assay of human S-cone function.
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Abstract
Unlike rod monochromatism, which is an autosomal recessive disease that affects all three types of cones, blue cone monochromatism (BCM) is an X-linked disease that affects only L-cones and M-cones. The rods and S-cones are normal. The estimated prevalence is 1 in 100,00 individuals.
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Affiliation(s)
- Stephen H Tsang
- Jonas Children's Vision Care, Bernard & Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative-Departments of Ophthalmology, Biomedical Engineering, Pathology & Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Department of Ophthalmology, Columbia University, Edward S. Harkness Eye Institute, NewYork-Presbyterian Hospital, New York, NY, USA
| | - Tarun Sharma
- Department of Ophthalmology, Columbia University, Edward S. Harkness Eye Institute, NewYork-Presbyterian Hospital, New York, NY, USA.
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Welby E, Lakowski J, Di Foggia V, Budinger D, Gonzalez-Cordero A, Lun ATL, Epstein M, Patel A, Cuevas E, Kruczek K, Naeem A, Minneci F, Hubank M, Jones DT, Marioni JC, Ali RR, Sowden JC. Isolation and Comparative Transcriptome Analysis of Human Fetal and iPSC-Derived Cone Photoreceptor Cells. Stem Cell Reports 2017; 9:1898-1915. [PMID: 29153988 PMCID: PMC5785701 DOI: 10.1016/j.stemcr.2017.10.018] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 10/14/2017] [Accepted: 10/15/2017] [Indexed: 11/20/2022] Open
Abstract
Loss of cone photoreceptors, crucial for daylight vision, has the greatest impact on sight in retinal degeneration. Transplantation of stem cell-derived L/M-opsin cones, which form 90% of the human cone population, could provide a feasible therapy to restore vision. However, transcriptomic similarities between fetal and stem cell-derived cones remain to be defined, in addition to development of cone cell purification strategies. Here, we report an analysis of the human L/M-opsin cone photoreceptor transcriptome using an AAV2/9.pR2.1:GFP reporter. This led to the identification of a cone-enriched gene signature, which we used to demonstrate similar gene expression between fetal and stem cell-derived cones. We then defined a cluster of differentiation marker combination that, when used for cell sorting, significantly enriches for cone photoreceptors from the fetal retina and stem cell-derived retinal organoids, respectively. These data may facilitate more efficient isolation of human stem cell-derived cones for use in clinical transplantation studies.
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Affiliation(s)
- Emily Welby
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Jorn Lakowski
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Valentina Di Foggia
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Dimitri Budinger
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Anai Gonzalez-Cordero
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Aaron T L Lun
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Michael Epstein
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Aara Patel
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Elisa Cuevas
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Kamil Kruczek
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Arifa Naeem
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Federico Minneci
- Department of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
| | - Mike Hubank
- UCL Genomics, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - David T Jones
- Department of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
| | - John C Marioni
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK; EMBL-European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Robin R Ali
- Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Jane C Sowden
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK.
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41
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Mechanisms of Photoreceptor Patterning in Vertebrates and Invertebrates. Trends Genet 2017; 32:638-659. [PMID: 27615122 DOI: 10.1016/j.tig.2016.07.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 11/22/2022]
Abstract
Across the animal kingdom, visual systems have evolved to be uniquely suited to the environments and behavioral patterns of different species. Visual acuity and color perception depend on the distribution of photoreceptor (PR) subtypes within the retina. Retinal mosaics can be organized into three broad categories: stochastic/regionalized, regionalized, and ordered. We describe here the retinal mosaics of flies, zebrafish, chickens, mice, and humans, and the gene regulatory networks controlling proper PR specification in each. By drawing parallels in eye development between these divergent species, we identify a set of conserved organizing principles and transcriptional networks that govern PR subtype differentiation.
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Zhang Y, Deng WT, Du W, Zhu P, Li J, Xu F, Sun J, Gerstner CD, Baehr W, Boye SL, Zhao C, Hauswirth WW, Pang JJ. Gene-based Therapy in a Mouse Model of Blue Cone Monochromacy. Sci Rep 2017; 7:6690. [PMID: 28751656 PMCID: PMC5532293 DOI: 10.1038/s41598-017-06982-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/14/2017] [Indexed: 02/08/2023] Open
Abstract
Cones are responsible for daylight, central, high acuity and color vision. Three proteins found in human cones, i.e. long-wavelength (L)-, middle-wavelength (M)-, and short-wavelength sensitive (S)-opsins, are responsible for red, green and blue color recognition, respectively. Human blue cone monochromacy (BCM) is characterized by functional loss of both L- and M-cone opsins due to mutations in the OPN1LW/OPN1MW gene cluster on the X chromosome. BCM patients, who rely on their vision from only S-cones and rods, suffer severely reduced visual acuity and impaired color vision. Recent studies show that there is sufficient cone structure remaining in the central fovea of BCM patients to consider AAV-mediated gene augmentation therapy. In contrast, mouse retina has only two opsins, S-opsin and M-opsin, but no L-opsin. We generated an M-opsin knockout mouse (Opn1mw -/-) expressing only S-opsin as a model for human BCM. We show that recombinant M-opsin delivered by AAV5 vectors rescues M-cone function in Opn1mw -/- mice. We also show that AAV delivered M-opsin localizes in the dorsal cone outer segments, and co-localizes with S-opsin in the ventral retina. Our study demonstrates that cones without M-opsin remain viable and respond to gene augmentation therapy, thereby providing proof-of-concept for cone function restoration in BCM patients.
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Affiliation(s)
- Yuxin Zhang
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Department of Ophthalmology, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Wen-Tao Deng
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Wei Du
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Ophthalmology Department of Peking University People's Hospital, Peking University People's Eye Center and Eye Institute, Beijing, China
| | - Ping Zhu
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Jie Li
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Fan Xu
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Jingfen Sun
- Ophthalmology, University of Florida, Gainesville, FL, USA
- Department of Obstetrics and Gynecology, Shanxi Dayi Hospital, Taiyuan, Shanxi Province, China
| | - Cecilia D Gerstner
- Opthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Wolfgang Baehr
- Opthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Sanford L Boye
- Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Chen Zhao
- Department of Ophthalmology, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
| | | | - Ji-Jing Pang
- Ophthalmology, University of Florida, Gainesville, FL, USA.
- Department of Ophthalmology, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
- Xiamen Eye Center of Xiamen University, Xiamen, Fujian, China.
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Xu Q, Hou YX, Chang XB. CRISPR/Cas9-Mediated Three Nucleotide Insertion Corrects a Deletion Mutation in MRP1/ABCC1 and Restores Its Proper Folding and Function. MOLECULAR THERAPY. NUCLEIC ACIDS 2017. [PMID: 28624219 PMCID: PMC5443964 DOI: 10.1016/j.omtn.2017.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A three-nucleotide deletion in cystic fibrosis transmembrane conductance regulator/ATP-binding cassette transporter C7 (CFTR/ABCC7) resulting in the absence of phenylalanine at 508 leads to mis-fold of the mutated protein and causes cystic fibrosis. We have used a comparable three-nucleotide deletion mutant in another ABCC family member, multidrug resistance-associated protein (MRP1)/ABCC1, to determine whether CRISPR-Cas9-mediated recombination can safely and efficiently knock in three-nucleotide to correct the mutation. We have found that the rate of homology-directed recombination mediated by guideRNA (gRNA) complementary to the deletion mutant is significantly higher than the one mediated by gRNA complementary to the wild-type (WT) donor. In addition, the rate of homology-directed recombination mediated by gRNA complementary to the WT donor is significantly higher than that of gRNAs complementary to the 5' or 3' side of the deletion mutant. Interestingly, the frequency of mutations introduced by gRNA complementary to the deletion mutant is significantly higher than with gRNA complementary to WT donor. However, combination of gRNAs complementary to both WT donor and deletion mutant decreased the rate of homology-directed recombination, but did not significantly decrease the mutation rate introduced by this system. Thus, the data presented here provide guidance for designing of gRNA and donor DNA to do genome editing, especially to correct the mutations with three mismatched nucleotides, such as three-nucleotide deletion or insertion.
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Affiliation(s)
- Qinqin Xu
- Department of Biochemistry & Molecular Biology, College of Medicine, Mayo Clinic in Arizona, Scottsdale, AZ 85259, USA
| | - Yue-Xian Hou
- Department of Biochemistry & Molecular Biology, College of Medicine, Mayo Clinic in Arizona, Scottsdale, AZ 85259, USA
| | - Xiu-Bao Chang
- Department of Biochemistry & Molecular Biology, College of Medicine, Mayo Clinic in Arizona, Scottsdale, AZ 85259, USA.
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Broadgate S, Yu J, Downes SM, Halford S. Unravelling the genetics of inherited retinal dystrophies: Past, present and future. Prog Retin Eye Res 2017; 59:53-96. [PMID: 28363849 DOI: 10.1016/j.preteyeres.2017.03.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 03/21/2017] [Accepted: 03/23/2017] [Indexed: 02/07/2023]
Abstract
The identification of the genes underlying monogenic diseases has been of interest to clinicians and scientists for many years. Using inherited retinal dystrophies as an example of monogenic disease we describe the history of molecular genetic techniques that have been pivotal in the discovery of disease causing genes. The methods that were developed in the 1970's and 80's are still in use today but have been refined and improved. These techniques enabled the concept of the Human Genome Project to be envisaged and ultimately realised. When the successful conclusion of the project was announced in 2003 many new tools and, as importantly, many collaborations had been developed that facilitated a rapid identification of disease genes. In the post-human genome project era advances in computing power and the clever use of the properties of DNA replication has allowed the development of next-generation sequencing technologies. These methods have revolutionised the identification of disease genes because for the first time there is no need to define the position of the gene in the genome. The use of next generation sequencing in a diagnostic setting has allowed many more patients with an inherited retinal dystrophy to obtain a molecular diagnosis for their disease. The identification of novel genes that have a role in the development or maintenance of retinal function is opening up avenues of research which will lead to the development of new pharmacological and gene therapy approaches. Neither of which can be used unless the defective gene and protein is known. The continued development of sequencing technologies also holds great promise for the advent of truly personalised medicine.
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Affiliation(s)
- Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Levels 5 and 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - Jing Yu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Levels 5 and 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - Susan M Downes
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, OX3 9DU, UK
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Levels 5 and 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK.
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De novo intrachromosomal gene conversion from OPN1MW to OPN1LW in the male germline results in Blue Cone Monochromacy. Sci Rep 2016; 6:28253. [PMID: 27339364 PMCID: PMC4919619 DOI: 10.1038/srep28253] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/01/2016] [Indexed: 12/21/2022] Open
Abstract
X-linked cone dysfunction disorders such as Blue Cone Monochromacy and X-linked Cone Dystrophy are characterized by complete loss (of) or reduced L- and M- cone function due to defects in the OPN1LW/OPN1MW gene cluster. Here we investigated 24 affected males from 16 families with either a structurally intact gene cluster or at least one intact single (hybrid) gene but harbouring rare combinations of common SNPs in exon 3 in single or multiple OPN1LW and OPN1MW gene copies. We assessed twelve different OPN1LW/MW exon 3 haplotypes by semi-quantitative minigene splicing assay. Nine haplotypes resulted in aberrant splicing of ≥20% of transcripts including the known pathogenic haplotypes (i.e. ‘LIAVA’, ‘LVAVA’) with absent or minute amounts of correctly spliced transcripts, respectively. De novo formation of the ‘LIAVA’ haplotype derived from an ancestral less deleterious ‘LIAVS’ haplotype was observed in one family with strikingly different phenotypes among affected family members. We could establish intrachromosomal gene conversion in the male germline as underlying mechanism. Gene conversion in the OPN1LW/OPN1MW genes has been postulated, however, we are first to demonstrate a de novo gene conversion within the lineage of a pedigree.
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Wang C, Hosono K, Kachi S, Suto K, Nakamura M, Terasaki H, Miyake Y, Hotta Y, Minoshima S. Novel OPN1LW/OPN1MW deletion mutations in 2 Japanese families with blue cone monochromacy. Hum Genome Var 2016; 3:16011. [PMID: 27274860 PMCID: PMC4880642 DOI: 10.1038/hgv.2016.11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/13/2016] [Accepted: 04/01/2016] [Indexed: 11/09/2022] Open
Abstract
Blue cone monochromacy (BCM) is caused by the lack of expression of the normal proteins encoded by the OPN1LW and OPN1MW genes, resulting in the absence of red and green cone sensitivities. We analyzed two cases of BCM in two different families and identified deletion mutations in the locus control region upstream of the two genes. Deletion breakpoints were determined to an accuracy of one base for both cases.
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Affiliation(s)
- Chunxia Wang
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan; Preeminent Medical Photonics Education & Research Center, Department of Photomedical Genomics, Institute for Medical Photonics Research, Hamamatsu University School of Medicine, Shizuoka, Japan; Department of Ophthalmology, the 4th affiliated hospital of China Medical University, Shenyang, China
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan; Preeminent Medical Photonics Education & Research Center, Department of Photomedical Genomics, Institute for Medical Photonics Research, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Shu Kachi
- Department of Ophthalmology, Nagoya University School of Medicine, Nagoya, Japan; Matsuura eye clinic, Sakae, Ichinomiya, Japan
| | - Kimiko Suto
- Department of Ophthalmology, Hamamatsu University School of Medicine , Shizuoka, Japan
| | - Makoto Nakamura
- Department of Ophthalmology, Nagoya University School of Medicine, Nagoya, Japan; Nakamura eye clinic, Nagoya, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University School of Medicine , Nagoya, Japan
| | | | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine , Shizuoka, Japan
| | - Shinsei Minoshima
- Preeminent Medical Photonics Education & Research Center, Department of Photomedical Genomics, Institute for Medical Photonics Research, Hamamatsu University School of Medicine , Shizuoka, Japan
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47
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Aboshiha J, Dubis AM, Carroll J, Hardcastle AJ, Michaelides M. The cone dysfunction syndromes. Br J Ophthalmol 2016; 100:115-21. [PMID: 25770143 PMCID: PMC4717370 DOI: 10.1136/bjophthalmol-2014-306505] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/09/2015] [Indexed: 11/05/2022]
Abstract
The cone dysfunction syndromes are a heterogeneous group of inherited, predominantly stationary retinal disorders characterised by reduced central vision and varying degrees of colour vision abnormalities, nystagmus and photophobia. This review details the following conditions: complete and incomplete achromatopsia, blue-cone monochromatism, oligocone trichromacy, bradyopsia and Bornholm eye disease. We describe the clinical, psychophysical, electrophysiological and imaging findings that are characteristic to each condition in order to aid their accurate diagnosis, as well as highlight some classically held notions about these diseases that have come to be challenged over the recent years. The latest data regarding the genetic aetiology and pathological changes observed in the cone dysfunction syndromes are discussed, and, where relevant, translational avenues of research, including completed and anticipated interventional clinical trials, for some of the diseases described herein will be presented. Finally, we briefly review the current management of these disorders.
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Affiliation(s)
- Jonathan Aboshiha
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Adam M Dubis
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Joseph Carroll
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Alison J Hardcastle
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
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48
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Simunovic MP. Acquired color vision deficiency. Surv Ophthalmol 2015; 61:132-55. [PMID: 26656928 DOI: 10.1016/j.survophthal.2015.11.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 11/06/2015] [Accepted: 11/11/2015] [Indexed: 02/02/2023]
Abstract
Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations.
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Affiliation(s)
- Matthew P Simunovic
- Nuffield Laboratory of Ophthalmology, University of Oxford & Oxford Eye Hospital, University of Oxford NHS Trust, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK.
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49
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Magini P, Poscente M, Ferrari S, Vargiolu M, Bacchelli E, Graziano C, Wischmeijer A, Turchetti D, Malaspina E, Marchiani V, Cordelli DM, Franzoni E, Romeo G, Seri M. Cytogenetic and molecular characterization of a recombinant X chromosome in a family with a severe neurologic phenotype and macular degeneration. Mol Cytogenet 2015; 8:58. [PMID: 26236399 PMCID: PMC4522089 DOI: 10.1186/s13039-015-0164-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/15/2015] [Indexed: 11/13/2022] Open
Abstract
Background Duplications of MECP2 gene in males cause a syndrome characterized by distinctive clinical features, including severe to profound mental retardation, infantile hypotonia, mild dysmorphic features, poor speech development, autistic features, seizures, progressive spasticity and recurrent infections. Patients with complex chromosome rearrangements, leading to Xq28 duplication, share most of the clinical features of individuals with tandem duplications, in particular neurologic problems, suggesting a major pathogenetic role of MECP2 overexpression. Results We performed cytogenetic and molecular cytogenetic studies in a previously described family with affected males showing congenital ataxia, late-onset progressive myoclonic encephalopathy and selective macular degeneration. Microsatellite, FISH and array-CGH analyses identified a recombinant X chromosome with a deletion of the PAR1 region, encompassing SHOX, replaced by a duplicated segment of the Xq28 terminal portion, including MECP2. Conclusions Our report describes the identification of the actual genetic cause underlying a severe syndrome that previous preliminary analyses erroneously associated to a terminal Xp22.33 region. In the present family as well as in previously reported patients with similar rearrangements, the observed neurologic phenotype is ascribable to MECP2 duplication, with an undefined contribution of the other involved genes. Maculopathy, presented by affected males reported here, could be a novel clinical feature associated to Xq28 disomy due to recombinant X chromosomes, but at present the underlying pathogenetic mechanism is unknown and this potential clinical correlation should be confirmed through the collection of additional patients.
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Affiliation(s)
- Pamela Magini
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
| | - Monica Poscente
- S.S.V.D. Biologia Molecolare, Citogenetica, Citomorfologia Ematica e Vaginale, Ospedale Belcolle, Viterbo, Italy
| | - Simona Ferrari
- U.O. Genetica Medica, AOU di Bologna, Policlinico S. Orsola-Malpighi, Bologna, 40138 Italy
| | - Manuela Vargiolu
- Centro Interdipartimentale per la Ricerca Industriale Scienze della Vita e Tecnologie per la Salute, Università di Bologna, Bologna, Italy
| | - Elena Bacchelli
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
| | - Claudio Graziano
- U.O. Genetica Medica, AOU di Bologna, Policlinico S. Orsola-Malpighi, Bologna, 40138 Italy
| | - Anita Wischmeijer
- U.O. Genetica Medica, AOU di Bologna, Policlinico S. Orsola-Malpighi, Bologna, 40138 Italy.,S.S.D. Genetica Clinica, Arcispedale S. Maria Nuova-Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia, Italy
| | - Daniela Turchetti
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
| | - Elisabetta Malaspina
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Valentina Marchiani
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Duccio Maria Cordelli
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Emilio Franzoni
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Giovanni Romeo
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
| | - Marco Seri
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
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50
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Hofmann L, Palczewski K. Advances in understanding the molecular basis of the first steps in color vision. Prog Retin Eye Res 2015; 49:46-66. [PMID: 26187035 DOI: 10.1016/j.preteyeres.2015.07.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/07/2015] [Accepted: 07/09/2015] [Indexed: 01/05/2023]
Abstract
Serving as one of our primary environmental inputs, vision is the most sophisticated sensory system in humans. Here, we present recent findings derived from energetics, genetics and physiology that provide a more advanced understanding of color perception in mammals. Energetics of cis-trans isomerization of 11-cis-retinal accounts for color perception in the narrow region of the electromagnetic spectrum and how human eyes can absorb light in the near infrared (IR) range. Structural homology models of visual pigments reveal complex interactions of the protein moieties with the light sensitive chromophore 11-cis-retinal and that certain color blinding mutations impair secondary structural elements of these G protein-coupled receptors (GPCRs). Finally, we identify unsolved critical aspects of color tuning that require future investigation.
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Affiliation(s)
- Lukas Hofmann
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - Krzysztof Palczewski
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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