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Bills JD, Seifert AW, Morris AC. Retinal neuroanatomy of two emerging model organisms, the spiny mouse (Acomys dimidiatus) and the Mongolian gerbil (Meriones unguiculatus). Exp Eye Res 2024; 247:110055. [PMID: 39159803 DOI: 10.1016/j.exer.2024.110055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 08/12/2024] [Accepted: 08/16/2024] [Indexed: 08/21/2024]
Abstract
Current research using animal models to investigate retinal cell biology and model retinal degenerative diseases largely utilize small mammals that are nocturnal and lack the ability to restore lost vision. In contrast, the Mongolian gerbil (Meriones) is a diurnal rodent with good photopic vision, and the spiny mouse (Acomys) is a small desert-dwelling rodent with remarkable regenerative capabilities. The goal of this study was to identify antibodies that detect retinal cell classes in Meriones and Acomys, and to describe the retinal anatomy of these two species in comparison to outbred laboratory mice (Mus musculus). Immunohistochemistry was performed on retinal sections with antibodies for various retinal cell types. Sections were imaged by light, fluorescence, and confocal microscopy. Cell density, morphology, and placement were compared between species qualitatively and quantitatively. Our analyses revealed a classic assembly of retinal cells in Meriones and Acomys, with a few deviations compared to Mus. Meriones displayed the highest density of cones and Acomys the lowest. A higher density of bipolar cell bodies in the proximal portion of the inner nuclear layer was observed in both Acomys and Meriones compared to Mus, and both species exhibited an increase in amacrine cell density compared to Mus. Our results provide a foundation for future research into the visual system adaptations of these interesting species.
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Affiliation(s)
- Jessica D Bills
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA
| | - Ashley W Seifert
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA
| | - Ann C Morris
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
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2
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Tipado Z, Kuypers KPC, Sorger B, Ramaekers JG. Visual hallucinations originating in the retinofugal pathway under clinical and psychedelic conditions. Eur Neuropsychopharmacol 2024; 85:10-20. [PMID: 38648694 DOI: 10.1016/j.euroneuro.2024.04.011] [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: 08/11/2023] [Revised: 04/11/2024] [Accepted: 04/13/2024] [Indexed: 04/25/2024]
Abstract
Psychedelics like LSD (Lysergic acid diethylamide) and psilocybin are known to modulate perceptual modalities due to the activation of mostly serotonin receptors in specific cortical (e.g., visual cortex) and subcortical (e.g., thalamus) regions of the brain. In the visual domain, these psychedelic modulations often result in peculiar disturbances of viewed objects and light and sometimes even in hallucinations of non-existent environments, objects, and creatures. Although the underlying processes are poorly understood, research conducted over the past twenty years on the subjective experience of psychedelics details theories that attempt to explain these perceptual alterations due to a disruption of communication between cortical and subcortical regions. However, rare medical conditions in the visual system like Charles Bonnet syndrome that cause perceptual distortions may shed new light on the additional importance of the retinofugal pathway in psychedelic subjective experiences. Interneurons in the retina called amacrine cells could be the first site of visual psychedelic modulation and aid in disrupting the hierarchical structure of how humans perceive visual information. This paper presents an understanding of how the retinofugal pathway communicates and modulates visual information in psychedelic and clinical conditions. Therefore, we elucidate a new theory of psychedelic modulation in the retinofugal pathway.
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Affiliation(s)
- Zeus Tipado
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands; Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands.
| | - Kim P C Kuypers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Bettina Sorger
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Johannes G Ramaekers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
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3
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Samadi Z, Askary A. Spatial motifs reveal patterns in cellular architecture of complex tissues. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.08.588586. [PMID: 38645046 PMCID: PMC11030378 DOI: 10.1101/2024.04.08.588586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Spatial organization of cells is crucial to both proper physiological function of tissues and pathological conditions like cancer. Recent advances in spatial transcriptomics have enabled joint profiling of gene expression and spatial context of the cells. The outcome is an information rich map of the tissue where individual cells, or small regions, can be labeled based on their gene expression state. While spatial transcriptomics excels in its capacity to profile numerous genes within the same sample, most existing methods for analysis of spatial data only examine distribution of one or two labels at a time. These approaches overlook the potential for identifying higher-order associations between cell types - associations that can play a pivotal role in understanding development and function of complex tissues. In this context, we introduce a novel method for detecting motifs in spatial neighborhood graphs. Each motif represents a spatial arrangement of cell types that occurs in the tissue more frequently than expected by chance. To identify spatial motifs, we developed an algorithm for uniform sampling of paths from neighborhood graphs and combined it with a motif finding algorithm on graphs inspired by previous methods for finding motifs in DNA sequences. Using synthetic data with known ground truth, we show that our method can identify spatial motifs with high accuracy and sensitivity. Applied to spatial maps of mouse retinal bipolar cells and hypothalamic preoptic region, our method reveals previously unrecognized patterns in cell type arrangements. In some cases, cells within these spatial patterns differ in their gene expression from other cells of the same type, providing insights into the functional significance of the spatial motifs. These results suggest that our method can illuminate the substantial complexity of neural tissues, provide novel insight even in well studied models, and generate experimentally testable hypotheses.
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Affiliation(s)
- Zainalabedin Samadi
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, 90095, CA, USA
| | - Amjad Askary
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, 90095, CA, USA
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Ablordeppey RK, Nieu R, Lin CR, Benavente-Perez A. Early Alterations in Inner-Retina Neural and Glial Saturated Responses in Lens-Induced Myopia. Transl Vis Sci Technol 2024; 13:16. [PMID: 38591944 PMCID: PMC11008749 DOI: 10.1167/tvst.13.4.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 03/11/2024] [Indexed: 04/10/2024] Open
Abstract
Purpose Myopic marmosets are known to exhibit significant inner retinal thinning compared to age-matched controls. The purpose of this study was to assess inner retinal activity in marmosets with lens-induced myopia compared to age-matched controls and evaluate its relationship with induced changes in refractive state and eye growth. Methods Cycloplegic refractive error (Rx), vitreous chamber depth (VCD), and photopic full-field electroretinogram were measured in 14 marmosets treated binocularly with negative contact lenses compared to 9 untreated controls at different stages throughout the experimental period (from 74 to 369 days of age). The implicit times of the a-, b-, d-, and photopic negative response (PhNR) waves, as well as the saturated amplitude (Vmax), semi-saturation constant (K), and slope (n) estimated from intensity-response functions fitted with Naka-Rushton equations were analyzed. Results Compared to controls, treated marmosets exhibited attenuated b-, d-, and PhNR waves Vmax amplitudes 7 to 14 days into treatment before compensatory changes in refraction and eye growth occurred. At later time points, when treated marmosets had developed axial myopia, the amplitudes and implicit times of the b-, d-, and PhNR waves were similar between groups. In controls, the PhNR wave saturated amplitude increased as the b + d-wave Vmax increased. This trend was absent in treated marmosets. Conclusions Marmosets induced with negative defocus exhibit early alterations in inner retinal saturated amplitudes compared to controls, prior to the development of compensatory myopia. These early ERG changes are independent of refraction and eye size and may reflect early changes in bipolar, ganglion, amacrine, or glial cell physiology prior to myopia development. Translational Relevance The early changes in retinal function identified in the negative lens-treated marmosets may serve as clinical biomarkers to help identify children at risk of developing myopia.
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Affiliation(s)
- Reynolds K. Ablordeppey
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY, USA
| | - Rita Nieu
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY, USA
| | - Carol R. Lin
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY, USA
| | - Alexandra Benavente-Perez
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY, USA
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5
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Hasan N, Gregg RG. Cone Synaptic function is modulated by the leucine rich repeat (LRR) adhesion molecule LRFN2. eNeuro 2024; 11:ENEURO.0120-23.2024. [PMID: 38408870 PMCID: PMC10957230 DOI: 10.1523/eneuro.0120-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 02/11/2024] [Accepted: 02/18/2024] [Indexed: 02/28/2024] Open
Abstract
Daylight vision is mediated by cone photoreceptors in vertebrates, which synapse with bipolar cells (BCs) and horizontal (HCs) cells. This cone synapse is functionally and anatomically complex, connecting to 8 types of depolarizing BCs (DBCs) and 5 types of hyperpolarizing BCs (HBCs) in mice. The dendrites of DBCs and HCs cells make invaginating ribbon synapses with the cone axon terminal, while HBCs form flat synapses with the cone pedicles. The molecular architecture that underpins this organization is relatively poorly understood. To identify new proteins involved in synapse formation and function we used an unbiased proteomic approach and identified LRFN2 (leucine-rich repeat and fibronectin III domain-containing 2) as a component of the DBC signaling complex. LRFN2 is selectively expressed at cone terminals and co-localizes with PNA, and other DBC signalplex members. In LRFN2 deficient mice, the synaptic markers: LRIT3, ELFN2, mGluR6, TRPM1 and GPR179 are properly localized. Similarly, LRFN2 expression and localization is not dependent on these synaptic proteins. In the absence of LRFN2 the cone-mediated photopic electroretinogram b-wave amplitude is reduced at the brightest flash intensities. These data demonstrate that LRFN2 absence compromises normal synaptic transmission between cones and cone DBCs.Significance Statement Signaling between cone photoreceptors and the downstream bipolar cells is critical to normal vision. Cones synapse with 13 different types of bipolar cells forming an invaginating ribbon synapses with 8 types, and flat synapses with 5 types, to form one of the most complex synapses in the brain. In this report a new protein, LRFN2 (leucine-rich repeat and fibronectin III domain-containing 2), was identified that is expressed at the cone synapse. Using Lrfn2 knockout mice we show LRFN2 is required for the normal cone signaling.
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Affiliation(s)
- Nazarul Hasan
- Departments of Biochemistry & Molecular Genetics, University of Louisville, Louisville, Kentucky 40202
- Ophthalmology & Visual Sciences, University of Louisville, Louisville, Kentucky 40202
| | - Ronald G. Gregg
- Departments of Biochemistry & Molecular Genetics, University of Louisville, Louisville, Kentucky 40202
- Ophthalmology & Visual Sciences, University of Louisville, Louisville, Kentucky 40202
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Masek M, Bachmann-Gagescu R. Control of protein and lipid composition of photoreceptor outer segments-Implications for retinal disease. Curr Top Dev Biol 2023; 155:165-225. [PMID: 38043951 DOI: 10.1016/bs.ctdb.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Vision is arguably our most important sense, and its loss brings substantial limitations to daily life for affected individuals. Light is perceived in retinal photoreceptors (PRs), which are highly specialized neurons subdivided into several compartments with distinct functions. The outer segments (OSs) of photoreceptors represent highly specialized primary ciliary compartments hosting the phototransduction cascade, which transforms incoming light into a neuronal signal. Retinal disease can result from various pathomechanisms originating in distinct subcompartments of the PR cell, or in the retinal pigment epithelium which supports the PRs. Dysfunction of primary cilia causes human disorders known as "ciliopathies", in which retinal disease is a common feature. This chapter focuses on PR OSs, discussing the mechanisms controlling their complex structure and composition. A sequence of tightly regulated sorting and trafficking events, both upstream of and within this ciliary compartment, ensures the establishment and maintenance of the adequate proteome and lipidome required for signaling in response to light. We discuss in particular our current understanding of the role of ciliopathy proteins involved in multi-protein complexes at the ciliary transition zone (CC2D2A) or BBSome (BBS1) and how their dysfunction causes retinal disease. While the loss of CC2D2A prevents the fusion of vesicles and delivery of the photopigment rhodopsin to the ciliary base, leading to early OS ultrastructural defects, BBS1 deficiency results in precocious accumulation of cholesterol in mutant OSs and decreased visual function preceding morphological changes. These distinct pathomechanisms underscore the central role of ciliary proteins involved in multiple processes controlling OS protein and lipid composition.
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Affiliation(s)
- Markus Masek
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland; University Research Priority Program AdaBD, University of Zurich, Zurich, Switzerland.
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Zhang X, Leavey P, Appel H, Makrides N, Blackshaw S. Molecular mechanisms controlling vertebrate retinal patterning, neurogenesis, and cell fate specification. Trends Genet 2023; 39:736-757. [PMID: 37423870 PMCID: PMC10529299 DOI: 10.1016/j.tig.2023.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 07/11/2023]
Abstract
This review covers recent advances in understanding the molecular mechanisms controlling neurogenesis and specification of the developing retina, with a focus on insights obtained from comparative single cell multiomic analysis. We discuss recent advances in understanding the mechanisms by which extrinsic factors trigger transcriptional changes that spatially pattern the optic cup (OC) and control the initiation and progression of retinal neurogenesis. We also discuss progress in unraveling the core evolutionarily conserved gene regulatory networks (GRNs) that specify early- and late-state retinal progenitor cells (RPCs) and neurogenic progenitors and that control the final steps in determining cell identity. Finally, we discuss findings that provide insight into regulation of species-specific aspects of retinal patterning and neurogenesis, including consideration of key outstanding questions in the field.
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Affiliation(s)
- Xin Zhang
- Department of Ophthalmology, Columbia University School of Medicine, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University School of Medicine, New York, NY, USA.
| | - Patrick Leavey
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Haley Appel
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Neoklis Makrides
- Department of Ophthalmology, Columbia University School of Medicine, New York, NY, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Psychiatry and Behavioral Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Choi J, Li J, Ferdous S, Liang Q, Moffitt JR, Chen R. Spatial organization of the mouse retina at single cell resolution by MERFISH. Nat Commun 2023; 14:4929. [PMID: 37582959 PMCID: PMC10427710 DOI: 10.1038/s41467-023-40674-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
The visual signal processing in the retina requires the precise organization of diverse neuronal types working in concert. While single-cell omics studies have identified more than 120 different neuronal subtypes in the mouse retina, little is known about their spatial organization. Here, we generated the single-cell spatial atlas of the mouse retina using multiplexed error-robust fluorescence in situ hybridization (MERFISH). We profiled over 390,000 cells and identified all major cell types and nearly all subtypes through the integration with reference single-cell RNA sequencing (scRNA-seq) data. Our spatial atlas allowed simultaneous examination of nearly all cell subtypes in the retina, revealing 8 previously unknown displaced amacrine cell subtypes and establishing the connection between the molecular classification of many cell subtypes and their spatial arrangement. Furthermore, we identified spatially dependent differential gene expression between subtypes, suggesting the possibility of functional tuning of neuronal types based on location.
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Affiliation(s)
- Jongsu Choi
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jin Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Salma Ferdous
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Qingnan Liang
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jeffrey R Moffitt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital; Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Rui Chen
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
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Peng YR. Cell-type specification in the retina: Recent discoveries from transcriptomic approaches. Curr Opin Neurobiol 2023; 81:102752. [PMID: 37499619 DOI: 10.1016/j.conb.2023.102752] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/29/2023]
Abstract
Understanding the formation of the complex nervous system hinges on decoding the mechanism that specifies a vast array of neuronal types, each endowed with a unique morphology, physiology, and connectivity. As a pivotal step towards addressing this problem, seminal work has been devoted to characterizing distinct neuronal types. In recent years, high-throughput, single-cell transcriptomic methods have enabled a rapid inventory of cell types in various regions of the nervous system, with the retina exhibiting complete molecular characterization across many vertebrate species. This invaluable resource has furnished a fresh perspective for investigating the molecular principles of cell-type specification, thereby advancing our understanding of retinal development. Accordingly, this review focuses on the most recent transcriptomic characterizations of retinal cells, with a particular focus on amacrine cells and retinal ganglion cells. These investigations have unearthed new insights into their cell-type specification.
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Affiliation(s)
- Yi-Rong Peng
- Department of Ophthalmology and Stein Eye Institute, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA.
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10
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Ge Y, Chen X, Nan N, Bard J, Wu F, Yergeau D, Liu T, Wang J, Mu X. Key transcription factors influence the epigenetic landscape to regulate retinal cell differentiation. Nucleic Acids Res 2023; 51:2151-2176. [PMID: 36715342 PMCID: PMC10018358 DOI: 10.1093/nar/gkad026] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 01/31/2023] Open
Abstract
How the diverse neural cell types emerge from multipotent neural progenitor cells during central nervous system development remains poorly understood. Recent scRNA-seq studies have delineated the developmental trajectories of individual neural cell types in many neural systems including the neural retina. Further understanding of the formation of neural cell diversity requires knowledge about how the epigenetic landscape shifts along individual cell lineages and how key transcription factors regulate these changes. In this study, we dissect the changes in the epigenetic landscape during early retinal cell differentiation by scATAC-seq and identify globally the enhancers, enriched motifs, and potential interacting transcription factors underlying the cell state/type specific gene expression in individual lineages. Using CUT&Tag, we further identify the enhancers bound directly by four key transcription factors, Otx2, Atoh7, Pou4f2 and Isl1, including those dependent on Atoh7, and uncover the sequential and combinatorial interactions of these factors with the epigenetic landscape to control gene expression along individual retinal cell lineages such as retinal ganglion cells (RGCs). Our results reveal a general paradigm in which transcription factors collaborate and compete to regulate the emergence of distinct retinal cell types such as RGCs from multipotent retinal progenitor cells (RPCs).
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Affiliation(s)
- Yichen Ge
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Xushen Chen
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Nan Nan
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA
| | - Jonathan Bard
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Fuguo Wu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Donald Yergeau
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Tao Liu
- Department of Biostatistics & Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Jie Wang
- Department of Biostatistics & Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
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Smirnov VM, Robert MP, Condroyer C, Navarro J, Antonio A, Rozet JM, Sahel JA, Perrault I, Audo I, Zeitz C. Association of Missense Variants in VSX2 With a Peculiar Form of Congenital Stationary Night Blindness Affecting All Bipolar Cells. JAMA Ophthalmol 2022; 140:1163-1173. [PMID: 36264558 PMCID: PMC9585472 DOI: 10.1001/jamaophthalmol.2022.4146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/23/2022] [Indexed: 01/12/2023]
Abstract
Importance Congenital stationary night blindness (CSNB) is an inherited stationary retinal disorder that is clinically and genetically heterogeneous. To date, the genetic association between some cases with CSNB and an unusual complex clinical picture is unclear. Objective To describe an unreported CSNB phenotype and the associated gene defect in 3 patients from 2 unrelated families. Design, Setting, and Participants This retrospective case series was conducted in 2021 and 2022 at a national referral center for rare ocular diseases. Data for 3 patients from a cohort of 140 genetically unsolved CSNB cases were analyzed clinically and genetically. Exposures Complete ocular examination including full-field electroretinography and multimodal fundus imaging (spectral-domain optical coherence tomography, color, infrared reflectance, and short-wavelength autofluorescence photographs) were performed. The gene defect was identified by exome sequencing and confirmed by Sanger sequencing and co-segregation analysis in 1 family. Screening was performed for genetically unsolved CSNB cases for VSX2 variants by direct Sanger sequencing. Main Outcomes and Measures Ocular and molecular biology findings. Results The series included 3 patients whose clinical investigations occurred at ages in the early 30s, younger than 12 years, and in the mid 40s. They had nystagmus, low stable visual acuity, and myopia from birth and experienced night blindness. Two older patients had bilateral lens luxation and underwent lens extraction. Full-field electroretinography revealed an electronegative Schubert-Bornschein appearance, combining characteristics of incomplete and complete CSNB, affecting the function of rod and cone ON- and OFF-bipolar cells. Exome sequencing and co-segregation analysis in a consanguineous family with 2 affected members identified a homozygous variant in VSX2. Subsequently, screening of the CSNB cohort identified another unrelated patient harboring a distinct VSX2 variant. Conclusions and Relevance This case series revealed a peculiar pan-bipolar cell retinopathy with lens luxation associated with variants in VSX2. Clinicians should be aware of this association and VSX2 added to CSNB diagnostic gene panels.
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Affiliation(s)
- Vasily M. Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Université de Lille, Faculté de Médecine, Lille, France
- Exploration de la Vision et Neuro-Ophtalmologie, CHU de Lille, Lille, France
| | - Matthieu P. Robert
- Ophthalmology Department, Hôpital Universitaire Necker-Enfants Malades, Paris, France
- Borelli Centre, UMR 9010, CNRS-SSA-ENS Paris Saclay-Paris University, Gif-sur-Yvette, France
| | | | - Julien Navarro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Aline Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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Vijayasarathy C, Zeng Y, Marangoni D, Dong L, Pan ZH, Simpson EM, Fariss RN, Sieving PA. Targeted Expression of Retinoschisin by Retinal Bipolar Cells in XLRS Promotes Resolution of Retinoschisis Cysts Sans RS1 From Photoreceptors. Invest Ophthalmol Vis Sci 2022; 63:8. [PMID: 36227606 PMCID: PMC9583743 DOI: 10.1167/iovs.63.11.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 09/18/2022] [Indexed: 01/14/2023] Open
Abstract
Purpose Loss of retinoschisin (RS1) function underlies X-linked retinoschisis (XLRS) pathology. In the retina, both photoreceptor inner segments and bipolar cells express RS1. However, the loss of RS1 function causes schisis primarily in the inner retina. To understand these cell type-specific phenotypes, we decoupled RS1 effects in bipolar cells from that in photoreceptors. Methods Bipolar cell transgene RS1 expression was achieved using two inner retina-specific promoters: (1) a minimal promoter engineered from glutamate receptor, metabotropic glutamate receptor 6 gene (mini-mGluR6/ Grm6) and (2) MiniPromoter (Ple155). Adeno-associated virus vectors encoding RS1 gene under either the mini-mGluR6 or Ple-155 promoter were delivered to the XLRS mouse retina through intravitreal or subretinal injection on postnatal day 14. Retinal structure and function were assessed 5 weeks later: immunohistochemistry for morphological characterization, optical coherence tomography and electroretinography (ERG) for structural and functional evaluation. Results Immunohistochemical analysis of RS1expression showed that expression with the MiniPromoter (Ple155) was heavily enriched in bipolar cells. Despite variations in vector penetrance and gene transfer efficiency across the injected retinas, those retinal areas with robust bipolar cell RS1 expression showed tightly packed bipolar cells with fewer cavities and marked improvement in inner retinal structure and synaptic function as judged by optical coherence tomography and electroretinography, respectively. Conclusions These results demonstrate that RS1 gene expression primarily in bipolar cells of the XLRS mouse retina, independent of photoreceptor expression, can ameliorate retinoschisis structural pathology and provide further evidence of RS1 role in cell adhesion.
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Affiliation(s)
- Camasamudram Vijayasarathy
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
| | - Yong Zeng
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
| | - Dario Marangoni
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
| | - Lijin Dong
- Genetic Engineering Facility, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Zhuo-Hua Pan
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Elizabeth M. Simpson
- Centre for Molecular Medicine and Therapeutics at BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert N. Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Paul A. Sieving
- Section for Translational Research in Retinal and Macular Degeneration, National Institutes of Health, Bethesda, Maryland, United States
- Center for Ocular Regenerative Therapy, Department of Ophthalmology, University of California Davis, United States
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13
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Bian F, Daghsni M, Lu F, Liu S, Gross JM, Aldiri I. Functional analysis of the Vsx2 super-enhancer uncovers distinct cis-regulatory circuits controlling Vsx2 expression during retinogenesis. Development 2022; 149:dev200642. [PMID: 35831950 PMCID: PMC9440754 DOI: 10.1242/dev.200642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/24/2022] [Indexed: 11/20/2022]
Abstract
Vsx2 is a transcription factor essential for retinal proliferation and bipolar cell differentiation, but the molecular mechanisms underlying its developmental roles are unclear. Here, we have profiled VSX2 genomic occupancy during mouse retinogenesis, revealing extensive retinal genetic programs associated with VSX2 during development. VSX2 binds and transactivates its enhancer in association with the transcription factor PAX6. Mice harboring deletions in the Vsx2 regulatory landscape exhibit specific abnormalities in retinal proliferation and in bipolar cell differentiation. In one of those deletions, a complete loss of bipolar cells is associated with a bias towards photoreceptor production. VSX2 occupies cis-regulatory elements nearby genes associated with photoreceptor differentiation and homeostasis in the adult mouse and human retina, including a conserved region nearby Prdm1, a factor implicated in the specification of rod photoreceptors and suppression of bipolar cell fate. VSX2 interacts with the transcription factor OTX2 and can act to suppress OTX2-dependent enhancer transactivation of the Prdm1 enhancer. Taken together, our analyses indicate that Vsx2 expression can be temporally and spatially uncoupled at the enhancer level, and they illuminate important mechanistic insights into how VSX2 is engaged with gene regulatory networks that are essential for retinal proliferation and cell fate acquisition.
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Affiliation(s)
- Fuyun Bian
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Marwa Daghsni
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Fangfang Lu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Silvia Liu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jeffrey M Gross
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Issam Aldiri
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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14
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Fain GL. Vision: Life on the dark side. Curr Biol 2022; 32:R741-R743. [PMID: 35820384 DOI: 10.1016/j.cub.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Mice detect decreases in illumination in dim light near the visual threshold with OFF retinal ganglion cells.
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Affiliation(s)
- Gordon L Fain
- Departments of Integrative Biology/Physiology and Ophthalmology, Stein Eye Institute, University of California, Los Angeles, CA 90095, USA.
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15
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Frederiksen R, Fain GL, Sampath AP. A hyperpolarizing rod bipolar cell in the sea lamprey, Petromyzon marinus. J Exp Biol 2022; 225:jeb243949. [PMID: 35319772 PMCID: PMC10658897 DOI: 10.1242/jeb.243949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 03/15/2022] [Indexed: 11/20/2022]
Abstract
Retinal bipolar cells receive direct input from rod and cone photoreceptors and send axons into the inner retina, synapsing onto amacrine and ganglion cells. Bipolar cell responses can be either depolarizing (ON) or hyperpolarizing (OFF); in lower vertebrates, bipolar cells receive mixed rod and cone input, whereas in mammals, input is mostly segregated into 14 classes of cone ON and OFF cells and a single rod ON bipolar cell. We show that lamprey, like mammals, have rod bipolar cells with little or no cone input, but these cells are OFF rather than ON. They have a characteristic morphology and a spectral sensitivity nearly indistinguishable from that of rod photoreceptors. In background light known to saturate rods, rod bipolar cells are also saturated and cannot respond to increment flashes. Our results suggest that early vertebrate progenitors of both agnathans and gnathostomes may have had a more fluid retinal organization than previously thought.
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Affiliation(s)
- Rikard Frederiksen
- Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-7000, USA
| | - Gordon L. Fain
- Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-7000, USA
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095-7239, USA
| | - Alapakkam P. Sampath
- Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-7000, USA
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16
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Cell Type-Selective Loss of Peroxisomal β-Oxidation Impairs Bipolar Cell but Not Photoreceptor Survival in the Retina. Cells 2022; 11:cells11010161. [PMID: 35011723 PMCID: PMC8750404 DOI: 10.3390/cells11010161] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/20/2021] [Accepted: 12/29/2021] [Indexed: 12/12/2022] Open
Abstract
Retinal degeneration is a common feature in peroxisomal disorders leading to blindness. Peroxisomes are present in the different cell types of the retina; however, their precise contribution to retinal integrity is still unclear. We previously showed that mice lacking the central peroxisomal β-oxidation enzyme, multifunctional protein 2 (MFP2), develop an early onset retinal decay including photoreceptor cell death. To decipher the function of peroxisomal β-oxidation in photoreceptors, we generated cell type selective Mfp2 knockout mice, using the Crx promotor targeting photoreceptors and bipolar cells. Surprisingly, Crx-Mfp2−/− mice maintained photoreceptor length and number until the age of 1 year. A negative electroretinogram was indicative of preserved photoreceptor phototransduction, but impaired downstream bipolar cell signaling from the age of 6 months. The photoreceptor ribbon synapse was affected, containing free-floating ribbons and vesicles with altered size and density. The bipolar cell interneurons sprouted into the ONL and died. Whereas docosahexaenoic acid levels were normal in the neural retina, levels of lipids containing very long chain polyunsaturated fatty acids were highly increased. Crx-Pex5−/− mice, in which all peroxisomal functions are inactivated in photoreceptors and bipolar cells, developed the same phenotype as Crx-Mfp2−/− mice. In conclusion, the early photoreceptor death in global Mfp2−/− mice is not driven cell autonomously. However, peroxisomal β-oxidation is essential for the integrity of photoreceptor ribbon synapses and of bipolar cells.
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