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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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Bai D, Guo R, Huang D, Ji J, Liu W. Compound heterozygous mutations in GRM6 causing complete Schubert-Bornschein type congenital stationary night blindness. Heliyon 2024; 10:e27039. [PMID: 38434377 PMCID: PMC10907788 DOI: 10.1016/j.heliyon.2024.e27039] [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: 09/11/2023] [Revised: 11/26/2023] [Accepted: 02/22/2024] [Indexed: 03/05/2024] Open
Abstract
Background To explore the genetic defects of a Chinese family with complete Schubert-Bornschein type congenital stationary night blindness (CSNB). Methods A Chinese family with complete Schubert-Bornschein type CSNB was enrolled in this study. The detailed ocular presentations of the patient were recorded. Targeted gene sequencing including 156 genes related to retinal diseases was used to detect the gene mutation. Sanger sequencing was performed to validate the potential pathogenic variants, and segregation analysis was performed on all available family members. Bioinformatics analysis was performed to predict the impact of the mutations. Results By targeted gene sequencing and Sanger sequencing, we identified compound heterozygous mutations in GRM6: c.152G>T (p.Gly51Val) and c.727delG (p.Val243SerfsX21). Segregation analysis demonstrated that the mother of the proband carried the missense mutation (c.152G>T) while her father carried the frameshift mutation (c.727delG), indicating CSNB was autosomal recessively inherited in this family. Several bioinformatics prediction programs revealed the mutations were "Damaging" or "Disease Causing" and conservation analysis showed both the codons Gly51 and Val243 were highly conserved among species, suggesting the changes were pathogenic. Conclusion By targeted gene sequencing and Sanger sequencing, we detected compound heterozygous mutations (c.152G>T, p.Gly51Val and c.727delG, p.Val243SerfsX21) in GRM6. The mutations co-segregated with the phenotype of the family members and are considered to be responsible for complete Schubert-Bornschein type CSNB. However, functional experiments in the future are needed to confirm the pathogenicity of the variants and to elucidate their exact molecular mechanisms causing CSNB.
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Affiliation(s)
- Dong'e Bai
- Department of Ophthalmology, Characteristic Medical Center of Chinese People's Armed Police Force, Tianjin, China
| | - Ruru Guo
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Dandan Huang
- Department of Ophthalmology, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, China
| | - Jian Ji
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Wei Liu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
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Senapati S, Park PSH. Understanding the Rhodopsin Worldview Through Atomic Force Microscopy (AFM): Structure, Stability, and Activity Studies. CHEM REC 2023; 23:e202300113. [PMID: 37265335 PMCID: PMC10908267 DOI: 10.1002/tcr.202300113] [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: 03/28/2023] [Revised: 05/12/2023] [Indexed: 06/03/2023]
Abstract
Rhodopsin is a G protein-coupled receptor (GPCR) present in the rod outer segment (ROS) of photoreceptor cells that initiates the phototransduction cascade required for scotopic vision. Due to the remarkable advancements in technological tools, the chemistry of rhodopsin has begun to unravel especially over the past few decades, but mostly at the ensemble scale. Atomic force microscopy (AFM) is a tool capable of providing critical information from a single-molecule point of view. In this regard, to bolster our understanding of rhodopsin at the nanoscale level, AFM-based imaging, force spectroscopy, and nano-indentation techniques were employed on ROS disc membranes containing rhodopsin, isolated from vertebrate species both in normal and diseased states. These AFM studies on samples from native retinal tissue have provided fundamental insights into the structure and function of rhodopsin under normal and dysfunctional states. We review here the findings from these AFM studies that provide important insights on the supramolecular organization of rhodopsin within the membrane and factors that contribute to this organization, the molecular interactions stabilizing the structure of the receptor and factors that can modify those interactions, and the mechanism underlying constitutive activity in the receptor that can cause disease.
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Affiliation(s)
- Subhadip Senapati
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
- Prayoga Institute of Education Research, Bengaluru, KA 560116, India
| | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
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Shimohata A, Rai D, Akagi T, Usui S, Ogiwara I, Kaneda M. The intracellular C-terminal domain of mGluR6 contains ER retention motifs. Mol Cell Neurosci 2023; 126:103875. [PMID: 37352898 DOI: 10.1016/j.mcn.2023.103875] [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: 03/20/2023] [Revised: 06/15/2023] [Accepted: 06/19/2023] [Indexed: 06/25/2023] Open
Abstract
Metabotropic glutamate receptor 6 (mGluR6) predominantly localizes to the postsynaptic sites of retinal ON-bipolar cells, at which it recognizes glutamate released from photoreceptors. The C-terminal domain (CTD) of mGluR6 contains a cluster of basic amino acids resembling motifs for endoplasmic reticulum (ER) retention. We herein investigated whether these basic residues are involved in regulating the subcellular localization of mGluR6 in 293T cells expressing mGluR6 CTD mutants using immunocytochemistry, immunoprecipitation, and flow cytometry. We showed that full-length mGluR6 localized to the ER and cell surface, whereas mGluR6 mutants with 15- and 20-amino acid deletions from the C terminus localized to the ER, but were deficient at the cell surface. We also demonstrated that the cell surface deficiency of mGluR6 mutants was rescued by introducing an alanine substitution at basic residues within the CTD. The surface-deficient mGluR6 mutant still did not localize to the cell surface and was retained in the ER when co-expressed with surface-expressible constructs, including full-length mGluR6, even though surface-deficient and surface-expressible constructs formed heteromeric complexes. The co-expression of the surface-deficient mGluR6 mutant reduced the surface levels of surface-expressible constructs. These results indicate that basic residues in the mGluR6 CTD served as ER retention signals. We suggest that exposed ER retention motifs in the aberrant assembly containing truncated or misfolded mGluR6 prevent these protein complexes from being transported to the cell surface.
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Affiliation(s)
- Atsushi Shimohata
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Dilip Rai
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Takumi Akagi
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Sumiko Usui
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Ikuo Ogiwara
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan.
| | - Makoto Kaneda
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
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Takahashi K, Kwok JC, Sato Y, Aguirre GD, Miyadera K. Extended functional rescue following AAV gene therapy in a canine model of LRIT3-congenital stationary night blindness. Vision Res 2023; 209:108260. [PMID: 37220680 PMCID: PMC10524691 DOI: 10.1016/j.visres.2023.108260] [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: 12/19/2022] [Revised: 04/21/2023] [Accepted: 04/21/2023] [Indexed: 05/25/2023]
Abstract
Congenital stationary night blindness (CSNB) is a group of inherited retinal diseases in which either rod-to-ON-bipolar cell (ON-BC) signaling, or rod function is affected leading to impaired vision under low light conditions. One type of CSNB is associated with defects in genes (NYX, GRM6, TRPM1, GPR179, and LRIT3) involved in the mGluR6 signaling cascade at the ON-BC dendritic tips. We have previously characterized a canine model of LRIT3-CSNB and demonstrated short-term safety and efficacy of an ON-BC targeting AAV-LRIT3 (AAVK9#4-shGRM6-cLRIT3-WPRE) gene therapy. Herein, we demonstrate long-term functional recovery and molecular restoration following subretinal injection of the ON-BC targeting AAV-LRIT3 vector in all eight treated eyes for up to 32 months. Following subretinal administration of the therapeutic vector, expression of the LRIT3 transgene, as well as restoration of mGluR6 signaling cascade member TRPM1, were confirmed in the outer plexiform layer (OPL) of the treated area. However, further investigation of the transgene LRIT3 transcript expression by RNA in situ hybridization (RNA-ISH) revealed off-target expression in non-BCs including the photoreceptors, inner nuclear, and ganglion cell layers, despite the use of a mutant AAVK9#4 capsid and an improved mGluR6 promoter designed to specifically transduce and promote expression in ON-BCs. While the long-term therapeutic potential of AAVK9#4-shGRM6-cLRIT3-WPRE is promising, we highlight the necessity for further optimization of AAV-LRIT3 therapy in the canine CSNB model prior to its clinical application.
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Affiliation(s)
- Kei Takahashi
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jennifer C Kwok
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yu Sato
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Keiko Miyadera
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Koller S, Beltraminelli T, Maggi J, Wlodarczyk A, Feil S, Baehr L, Gerth-Kahlert C, Menghini M, Berger W. Functional Analysis of a Novel, Non-Canonical RPGR Splice Variant Causing X-Linked Retinitis Pigmentosa. Genes (Basel) 2023; 14:genes14040934. [PMID: 37107692 PMCID: PMC10137330 DOI: 10.3390/genes14040934] [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: 03/20/2023] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
X-linked retinitis pigmentosa (XLRP) caused by mutations in the RPGR gene is one of the most severe forms of RP due to its early onset and intractable progression. Most cases have been associated with genetic variants within the purine-rich exon ORF15 region of this gene. RPGR retinal gene therapy is currently being investigated in several clinical trials. Therefore, it is crucial to report and functionally characterize (all novel) potentially pathogenic DNA sequence variants. Whole-exome sequencing (WES) was performed for the index patient. The splicing effects of a non-canonical splice variant were tested on cDNA from whole blood and a minigene assay. WES revealed a rare, non-canonical splice site variant predicted to disrupt the wildtype splice acceptor and create a novel acceptor site 8 nucleotides upstream of RPGR exon 12. Reverse-transcription PCR analyses confirmed the disruption of the correct splicing pattern, leading to the insertion of eight additional nucleotides in the variant transcript. Transcript analyses with minigene assays and cDNA from peripheral blood are useful tools for the characterization of splicing defects due to variants in the RPGR and may increase the diagnostic yield in RP. The functional analysis of non-canonical splice variants is required to classify those variants as pathogenic according to the ACMG's criteria.
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Affiliation(s)
- Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Tim Beltraminelli
- Department of Ophthalmology, Institute of Clinical Neurosciences of Southern Switzerland, Ente Ospedaliero Cantonale (EOC), 6962 Lugano, Switzerland
| | - Jordi Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Agnès Wlodarczyk
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Luzy Baehr
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital, University of Zurich, 8091 Zurich, Switzerland
| | - Moreno Menghini
- Department of Ophthalmology, Institute of Clinical Neurosciences of Southern Switzerland, Ente Ospedaliero Cantonale (EOC), 6962 Lugano, Switzerland
- Department of Ophthalmology, University Hospital, University of Zurich, 8091 Zurich, Switzerland
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), University and ETH Zurich, 8057 Zurich, Switzerland
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7
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Zeitz C, Roger JE, Audo I, Michiels C, Sánchez-Farías N, Varin J, Frederiksen H, Wilmet B, Callebert J, Gimenez ML, Bouzidi N, Blond F, Guilllonneau X, Fouquet S, Léveillard T, Smirnov V, Vincent A, Héon E, Sahel JA, Kloeckener-Gruissem B, Sennlaub F, Morgans CW, Duvoisin RM, Tkatchenko AV, Picaud S. Shedding light on myopia by studying complete congenital stationary night blindness. Prog Retin Eye Res 2023; 93:101155. [PMID: 36669906 DOI: 10.1016/j.preteyeres.2022.101155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 01/20/2023]
Abstract
Myopia is the most common eye disorder, caused by heterogeneous genetic and environmental factors. Rare progressive and stationary inherited retinal disorders are often associated with high myopia. Genes implicated in myopia encode proteins involved in a variety of biological processes including eye morphogenesis, extracellular matrix organization, visual perception, circadian rhythms, and retinal signaling. Differentially expressed genes (DEGs) identified in animal models mimicking myopia are helpful in suggesting candidate genes implicated in human myopia. Complete congenital stationary night blindness (cCSNB) in humans and animal models represents an ON-bipolar cell signal transmission defect and is also associated with high myopia. Thus, it represents also an interesting model to identify myopia-related genes, as well as disease mechanisms. While the origin of night blindness is molecularly well established, further research is needed to elucidate the mechanisms of myopia development in subjects with cCSNB. Using whole transcriptome analysis on three different mouse models of cCSNB (in Gpr179-/-, Lrit3-/- and Grm6-/-), we identified novel actors of the retinal signaling cascade, which are also novel candidate genes for myopia. Meta-analysis of our transcriptomic data with published transcriptomic databases and genome-wide association studies from myopia cases led us to propose new biological/cellular processes/mechanisms potentially at the origin of myopia in cCSNB subjects. The results provide a foundation to guide the development of pharmacological myopia therapies.
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Affiliation(s)
- Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.
| | - Jérome E Roger
- Paris-Saclay Institute of Neuroscience, CERTO-Retina France, CNRS, Université Paris-Saclay, Saclay, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France
| | | | | | - Juliette Varin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Helen Frederiksen
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Baptiste Wilmet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jacques Callebert
- Service of Biochemistry and Molecular Biology, INSERM U942, Hospital Lariboisière, APHP, Paris, France
| | | | - Nassima Bouzidi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Frederic Blond
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Stéphane Fouquet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Vasily Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France; Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | | | - Florian Sennlaub
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Catherine W Morgans
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA
| | - Robert M Duvoisin
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA
| | - Andrei V Tkatchenko
- Oujiang Laboratory, Zhejiang Laboratory for Regenerative Medicine, Vision and Brain Health, Wenzhou, China; Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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Wilmet B, Callebert J, Duvoisin R, Goulet R, Tourain C, Michiels C, Frederiksen H, Schaeffel F, Marre O, Sahel JA, Audo I, Picaud S, Zeitz C. Mice Lacking Gpr179 with Complete Congenital Stationary Night Blindness Are a Good Model for Myopia. Int J Mol Sci 2022; 24:ijms24010219. [PMID: 36613663 PMCID: PMC9820543 DOI: 10.3390/ijms24010219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/25/2022] Open
Abstract
Mutations in GPR179 are one of the most common causes of autosomal recessive complete congenital stationary night blindness (cCSNB). This retinal disease is characterized in patients by impaired dim and night vision, associated with other ocular symptoms, including high myopia. cCSNB is caused by a complete loss of signal transmission from photoreceptors to ON-bipolar cells. In this study, we hypothesized that the lack of Gpr179 and the subsequent impaired ON-pathway could lead to myopic features in a mouse model of cCSNB. Using ultra performance liquid chromatography, we show that adult Gpr179-/- mice have a significant decrease in both retinal dopamine and 3,4-dihydroxyphenylacetic acid, compared to Gpr179+/+ mice. This alteration of the dopaminergic system is thought to be correlated with an increased susceptibility to lens-induced myopia but does not affect the natural refractive development. Altogether, our data added a novel myopia model, which could be used to identify therapeutic interventions.
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Affiliation(s)
- Baptiste Wilmet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Correspondence: (B.W.); (C.Z.); Tel.: +33-1-53-46-25-26 (B.W.); +33-1-53-46-25-40 (C.Z.)
| | - Jacques Callebert
- Service of Biochemistry and Molecular Biology, INSERM U942, Hospital Lariboisière, AP-HP, 75010 Paris, France
| | - Robert Duvoisin
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ruben Goulet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Christophe Tourain
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, Paris Descartes University, 75270 Paris, France
| | - Christelle Michiels
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Helen Frederiksen
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Frank Schaeffel
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4056 Basel, Switzerland
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, University of Tuebingen, 72076 Tuebingen, Germany
- Zeiss Vision Lab, Ophthalmic Research Institute, University of Tuebingen, 72076 Tuebingen, Germany
| | - Olivier Marre
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - José Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, 75012 Paris, France
- Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France
- Académie des Sciences, Institut de France, 75006 Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, 75012 Paris, France
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Correspondence: (B.W.); (C.Z.); Tel.: +33-1-53-46-25-26 (B.W.); +33-1-53-46-25-40 (C.Z.)
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Smirnov VM, Robert MP, Condroyer C, Navarro J, Antonio A, Rozet JM, Sahel JA, Perrault I, Audo I, Zeitz C. Association of Missense Variants in VSX2 With a Peculiar Form of Congenital Stationary Night Blindness Affecting All Bipolar Cells. JAMA Ophthalmol 2022; 140:1163-1173. [PMID: 36264558 PMCID: PMC9585472 DOI: 10.1001/jamaophthalmol.2022.4146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/23/2022] [Indexed: 01/12/2023]
Abstract
Importance Congenital stationary night blindness (CSNB) is an inherited stationary retinal disorder that is clinically and genetically heterogeneous. To date, the genetic association between some cases with CSNB and an unusual complex clinical picture is unclear. Objective To describe an unreported CSNB phenotype and the associated gene defect in 3 patients from 2 unrelated families. Design, Setting, and Participants This retrospective case series was conducted in 2021 and 2022 at a national referral center for rare ocular diseases. Data for 3 patients from a cohort of 140 genetically unsolved CSNB cases were analyzed clinically and genetically. Exposures Complete ocular examination including full-field electroretinography and multimodal fundus imaging (spectral-domain optical coherence tomography, color, infrared reflectance, and short-wavelength autofluorescence photographs) were performed. The gene defect was identified by exome sequencing and confirmed by Sanger sequencing and co-segregation analysis in 1 family. Screening was performed for genetically unsolved CSNB cases for VSX2 variants by direct Sanger sequencing. Main Outcomes and Measures Ocular and molecular biology findings. Results The series included 3 patients whose clinical investigations occurred at ages in the early 30s, younger than 12 years, and in the mid 40s. They had nystagmus, low stable visual acuity, and myopia from birth and experienced night blindness. Two older patients had bilateral lens luxation and underwent lens extraction. Full-field electroretinography revealed an electronegative Schubert-Bornschein appearance, combining characteristics of incomplete and complete CSNB, affecting the function of rod and cone ON- and OFF-bipolar cells. Exome sequencing and co-segregation analysis in a consanguineous family with 2 affected members identified a homozygous variant in VSX2. Subsequently, screening of the CSNB cohort identified another unrelated patient harboring a distinct VSX2 variant. Conclusions and Relevance This case series revealed a peculiar pan-bipolar cell retinopathy with lens luxation associated with variants in VSX2. Clinicians should be aware of this association and VSX2 added to CSNB diagnostic gene panels.
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Affiliation(s)
- Vasily M. Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Université de Lille, Faculté de Médecine, Lille, France
- Exploration de la Vision et Neuro-Ophtalmologie, CHU de Lille, Lille, France
| | - Matthieu P. Robert
- Ophthalmology Department, Hôpital Universitaire Necker-Enfants Malades, Paris, France
- Borelli Centre, UMR 9010, CNRS-SSA-ENS Paris Saclay-Paris University, Gif-sur-Yvette, France
| | | | - Julien Navarro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Aline Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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10
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Cao Y, Fajardo D, Guerrero-Given D, Samuel MA, Ohtsuka T, Boye SE, Kamasawa N, Martemyanov KA. Post-developmental plasticity of the primary rod pathway allows restoration of visually guided behaviors. Curr Biol 2022; 32:4783-4796.e3. [PMID: 36179691 PMCID: PMC9691582 DOI: 10.1016/j.cub.2022.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/17/2022] [Accepted: 09/08/2022] [Indexed: 01/24/2023]
Abstract
The formation of neural circuits occurs in a programmed fashion, but proper activity in the circuit is essential for refining the organization necessary for driving complex behavioral tasks. In the retina, sensory deprivation during the critical period of development is well known to perturb the organization of the visual circuit making the animals unable to use vision for behavior. However, the extent of plasticity, molecular factors involved, and malleability of individual channels in the circuit to manipulations outside of the critical period are not well understood. In this study, we selectively disconnected and reconnected rod photoreceptors in mature animals after completion of the retina circuit development. We found that introducing synaptic rod photoreceptor input post-developmentally allowed their integration into the circuit both anatomically and functionally. Remarkably, adult mice with newly integrated rod photoreceptors gained high-sensitivity vision, even when it was absent from birth. These observations reveal plasticity of the retina circuit organization after closure of the critical period and encourage the development of vision restoration strategies for congenital blinding disorders.
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Affiliation(s)
- Yan Cao
- Department of Neuroscience, UF Scripps Biomedical Research, Jupiter, FL 33458, USA
| | - Diego Fajardo
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Debbie Guerrero-Given
- The Imaging Center, Electron Microscopy Core Facility, Max Planck Florida Institute, 1 Max Planck Way, Jupiter, FL 33458, USA
| | - Melanie A Samuel
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Toshihisa Ohtsuka
- Department of Biochemistry, Graduate School of Medicine, Faculty of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Shannon E Boye
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Naomi Kamasawa
- The Imaging Center, Electron Microscopy Core Facility, Max Planck Florida Institute, 1 Max Planck Way, Jupiter, FL 33458, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, UF Scripps Biomedical Research, Jupiter, FL 33458, USA.
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11
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Garanto A, Ferreira CR, Boon CJF, van Karnebeek CDM, Blau N. Clinical and biochemical footprints of inherited metabolic disorders. VII. Ocular phenotypes. Mol Genet Metab 2022; 135:311-319. [PMID: 35227579 PMCID: PMC10518078 DOI: 10.1016/j.ymgme.2022.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/19/2022] [Accepted: 02/11/2022] [Indexed: 12/11/2022]
Abstract
Ocular manifestations are observed in approximately one third of all inherited metabolic disorders (IMDs). Although ocular involvement is not life-threatening, it can result in severe vision loss, thereby leading to an additional burden for the patient. Retinal degeneration with or without optic atrophy is the most frequent phenotype, followed by oculomotor problems, involvement of the cornea and lens, and refractive errors. These phenotypes can provide valuable clues that contribute to its diagnosis. In this issue we found 577 relevant IMDs leading to ophthalmologic manifestations. This article is the seventh of a series attempting to create and maintain a comprehensive list of clinical and metabolic differential diagnoses according to system involvement.
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Affiliation(s)
- Alejandro Garanto
- Department of Pediatrics, Amalia Children's Hospital Radboud Center for Mitochondrial and Metabolic Diseases, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Carlos R Ferreira
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands and Amsterdam University Medical Centers, Academic Medical Center, Department of Ophthalmology, University of Amsterdam, Amsterdam, the Netherlands.
| | - Clara D M van Karnebeek
- Department of Pediatrics, Amalia Children's Hospital Radboud Center for Mitochondrial and Metabolic Diseases, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Departments of Pediatrics and Human Genetics, Emma Children's Hospital, Amsterdam Reproduction and Development, Amsterdam University Medical Centers, Amsterdam, the Netherlands.
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital, Zürich, Switzerland.
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12
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Miyadera K, Santana E, Roszak K, Iffrig S, Visel M, Iwabe S, Boyd RF, Bartoe JT, Sato Y, Gray A, Ripolles-Garcia A, Dufour VL, Byrne LC, Flannery JG, Beltran WA, Aguirre GD. Targeting ON-bipolar cells by AAV gene therapy stably reverses LRIT3-congenital stationary night blindness. Proc Natl Acad Sci U S A 2022; 119:e2117038119. [PMID: 35316139 PMCID: PMC9060458 DOI: 10.1073/pnas.2117038119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/10/2022] [Indexed: 01/08/2023] Open
Abstract
SignificanceCanine models of inherited retinal diseases have helped advance adeno-associated virus (AAV)-based gene therapies targeting specific cells in the outer retina for treating blinding diseases in patients. However, therapeutic targeting of diseases such as congenital stationary night blindness (CSNB) that exhibit defects in ON-bipolar cells (ON-BCs) of the midretina remains underdeveloped. Using a leucine-rich repeat, immunoglobulin-like and transmembrane domain 3 (LRIT3) mutant canine model of CSNB exhibiting ON-BC dysfunction, we tested the ability of cell-specific AAV capsids and promotors to specifically target ON-BCs for gene delivery. Subretinal injection of one vector demonstrated safety and efficacy with robust and stable rescue of electroretinography signals and night vision up to 1 y, paving the way for clinical trials in patients.
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Affiliation(s)
- Keiko Miyadera
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Evelyn Santana
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Karolina Roszak
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Sommer Iffrig
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Meike Visel
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Simone Iwabe
- Ophthalmology Services, Charles River Laboratories, Mattawan, MI 49071
| | - Ryan F. Boyd
- Ophthalmology Services, Charles River Laboratories, Mattawan, MI 49071
| | - Joshua T. Bartoe
- Ophthalmology Services, Charles River Laboratories, Mattawan, MI 49071
| | - Yu Sato
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Alexa Gray
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Ana Ripolles-Garcia
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Valérie L. Dufour
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Leah C. Byrne
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - John G. Flannery
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - William A. Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gustavo D. Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
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13
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Agosto MA, Adeosun AAR, Kumar N, Wensel TG. The mGluR6 ligand-binding domain, but not the C-terminal domain, is required for synaptic localization in retinal ON-bipolar cells. J Biol Chem 2021; 297:101418. [PMID: 34793838 PMCID: PMC8671642 DOI: 10.1016/j.jbc.2021.101418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 11/26/2022] Open
Abstract
Signals from retinal photoreceptors are processed in two parallel channels—the ON channel responds to light increments, while the OFF channel responds to light decrements. The ON pathway is mediated by ON type bipolar cells (BCs), which receive glutamatergic synaptic input from photoreceptors via a G-protein-coupled receptor signaling cascade. The metabotropic glutamate receptor mGluR6 is located at the dendritic tips of all ON-BCs and is required for synaptic transmission. Thus, it is critically important for delivery of information from photoreceptors into the ON pathway. In addition to detecting glutamate, mGluR6 participates in interactions with other postsynaptic proteins, as well as trans-synaptic interactions with presynaptic ELFN proteins. Mechanisms of mGluR6 synaptic targeting and functional interaction with other synaptic proteins are unknown. Here, we show that multiple regions in the mGluR6 ligand-binding domain are necessary for both synaptic localization in BCs and ELFN1 binding in vitro. However, these regions were not required for plasma membrane localization in heterologous cells, indicating that secretory trafficking and synaptic localization are controlled by different mechanisms. In contrast, the mGluR6 C-terminus was dispensable for synaptic localization. In mGluR6 null mice, localization of the postsynaptic channel protein TRPM1 was compromised. Introducing WT mGluR6 rescued TRPM1 localization, while a C-terminal deletion mutant had significantly reduced rescue ability. We propose a model in which trans-synaptic ELFN1 binding is necessary for mGluR6 postsynaptic localization, whereas the C-terminus has a role in mediating TRPM1 trafficking. These findings reveal different sequence determinants of the multifunctional roles of mGluR6 in ON-BCs.
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Affiliation(s)
- Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA.
| | - Abiodun Adefola R Adeosun
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA; Pharmacology and Chemical Biology Graduate Program, Baylor College of Medicine, Houston TX, USA
| | - Nitin Kumar
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA; Pharmacology and Chemical Biology Graduate Program, Baylor College of Medicine, Houston TX, USA
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14
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The Inhibition of the Degrading Enzyme Fatty Acid Amide Hydrolase Alters the Activity of the Cone System in the Vervet Monkey Retina. Brain Sci 2021; 11:brainsci11111418. [PMID: 34827417 PMCID: PMC8615683 DOI: 10.3390/brainsci11111418] [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: 09/27/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Recent studies using full-field electroretinography (ffERG) that triggers a non-specific mass response generated by several retinal sources have attributed an important role for cannabinoid receptors in mediating vision in primates. Specific cone-mediated responses evoked through the photopic flicker ERG appear to be a better way to validate the assumption that endogenous cannabinoids modulate the cone pathway, since FAAH is mainly expressed in the vervet monkey cone photoreceptors. The aim of this study is two-fold: (1) to use the photopic flicker ERG to target the cone pathway specifically, and (2) use URB597 as a selective inhibitor of the endocannabinoid degrading enzyme Fatty Acid Amide Hydrolase (FAAH) to enhance the levels of fatty acid amides, particularly anandamide. We recorded ERGs under four different flicker frequencies (15, 20, 25, and 30 Hz) in light-adapted conditions after intravitreal injections of URB597. Our results show that intravitreal injections of URB597, compared to the vehicle DMSO, increased significantly ffERG amplitudes at 30 Hz, a frequency that solely recruits cone activity. However, at 15 Hz, a frequency that activates both rods and cones, no significant difference was found in the ERG response amplitude. Additionally, we found no differences in implicit times after URB597 injections compared to DMSO vehicle. These results support the role of molecules degraded by FAAH in cone-mediated vision in non-human primates.
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15
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Varin J, Bouzidi N, Gauvain G, Joffrois C, Desrosiers M, Robert C, De Sousa Dias MM, Neuillé M, Michiels C, Nassisi M, Sahel JA, Picaud S, Audo I, Dalkara D, Zeitz C. Substantial restoration of night vision in adult mice with congenital stationary night blindness. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 22:15-25. [PMID: 34401402 PMCID: PMC8339357 DOI: 10.1016/j.omtm.2021.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 05/13/2021] [Indexed: 11/27/2022]
Abstract
Complete congenital stationary night blindness (cCSNB) due to mutations in TRPM1, GRM6, GPR179, NYX, or leucine-rich repeat immunoglobulin-like transmembrane domain 3 (LRIT3) is an incurable inherited retinal disorder characterized by an ON-bipolar cell (ON-BC) defect. Since the disease is non-degenerative and stable, treatment could theoretically be administrated at any time in life, making it a promising target for gene therapy. Until now, adeno-associated virus (AAV)-mediated therapies lead to significant functional improvements only in newborn cCSNB mice. Here we aimed to restore protein localization and function in adult Lrit3 -/ - mice. LRIT3 localizes in the outer plexiform layer and is crucial for TRPM1 localization at the dendritic tips of ON-BCs and the electroretinogram (ERG)-b-wave. AAV2-7m8-Lrit3 intravitreal injections were performed targeting either ON-BCs, photoreceptors (PRs), or both. Protein localization of LRIT3 and TRPM1 at the rod-to-rod BC synapse, functional rescue of scotopic responses, and ON-responses detection at the ganglion cell level were achieved in a few mice when ON-BCs alone or both PRs and ON-BCs, were targeted. More importantly, a significant number of treated adult Lrit3 -/- mice revealed an ERG b-wave recovery under scotopic conditions, improved optomotor responses, and on-time ON-responses at the ganglion cell level when PRs were targeted. Functional rescue was maintained for at least 4 months after treatment.
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Affiliation(s)
- Juliette Varin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Nassima Bouzidi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Gregory Gauvain
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Corentin Joffrois
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Camille Robert
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Marion Neuillé
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Marco Nassisi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, Paris, France.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Academie des Sciences, Institut de France, Paris, France.,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, UK
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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16
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Kim HM, Joo K, Han J, Woo SJ. Clinical and Genetic Characteristics of Korean Congenital Stationary Night Blindness Patients. Genes (Basel) 2021; 12:genes12060789. [PMID: 34064005 PMCID: PMC8224030 DOI: 10.3390/genes12060789] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/11/2021] [Accepted: 05/18/2021] [Indexed: 01/27/2023] Open
Abstract
In this study, we investigated the clinical and genetic characteristics of 19 Korean patients with congenital stationary night blindness (CSNB) at two tertiary hospitals. Clinical evaluations, including fundus photography, spectral-domain optical coherence tomography, and electroretinography, were performed. Genetic analyses were conducted using targeted panel sequencing or whole exome sequencing. The median age was 5 (3–21) years at the initial examination, 2 (1–8) years at symptom onset, and 11 (5–28) years during the final visit. Genetic mutations were identified as CNGB1 and GNAT1 for the Riggs type (n = 2), TRPM1 and NYX for the complete type (n = 3), and CACNA1F (n = 14) for the incomplete type. Ten novel variants were identified, and best-corrected visual acuity (BCVA) and spherical equivalents (SE) were related to each type of CSNB. The Riggs and TRPM1 complete types presented mild myopia and good BCVA without strabismus and nystagmus, whereas the NYX complete and incomplete types showed mixed SE and poor BCVA with strabismus and nystagmus. This is the first case series of Korean patients with CSNB, and further studies with a larger number of subjects should be conducted to correlate the clinical and genetic aspects of CSNB.
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Affiliation(s)
- Hyeong-Min Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea; (H.-M.K.); (K.J.)
| | - Kwangsic Joo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea; (H.-M.K.); (K.J.)
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea
- Correspondence: (J.H.); (S.-J.W.); Tel.: +82-2-2019-3445 (J.H.); +82-31-787-7377 (S.-J.W.); Fax: +82-2-3463-1049 (J.H.); +82-31-787-4057 (S.-J.W.)
| | - Se-Joon Woo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea; (H.-M.K.); (K.J.)
- Correspondence: (J.H.); (S.-J.W.); Tel.: +82-2-2019-3445 (J.H.); +82-31-787-7377 (S.-J.W.); Fax: +82-2-3463-1049 (J.H.); +82-31-787-4057 (S.-J.W.)
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17
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Orhan E, Neuillé M, de Sousa Dias M, Pugliese T, Michiels C, Condroyer C, Antonio A, Sahel JA, Audo I, Zeitz C. A New Mouse Model for Complete Congenital Stationary Night Blindness Due to Gpr179 Deficiency. Int J Mol Sci 2021; 22:ijms22094424. [PMID: 33922602 PMCID: PMC8122890 DOI: 10.3390/ijms22094424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 01/24/2023] Open
Abstract
Mutations in GPR179 lead to autosomal recessive complete congenital stationary night blindness (cCSNB). This condition represents a signal transmission defect from the photoreceptors to the ON-bipolar cells. To confirm the phenotype, better understand the pathogenic mechanism in vivo, and provide a model for therapeutic approaches, a Gpr179 knock-out mouse model was genetically and functionally characterized. We confirmed that the insertion of a neo/lac Z cassette in intron 1 of Gpr179 disrupts the same gene. Spectral domain optical coherence tomography reveals no obvious retinal structure abnormalities. Gpr179 knock-out mice exhibit a so-called no-b-wave (nob) phenotype with severely reduced b-wave amplitudes in the electroretinogram. Optomotor tests reveal decreased optomotor responses under scotopic conditions. Consistent with the genetic disruption of Gpr179, GPR179 is absent at the dendritic tips of ON-bipolar cells. While proteins of the same signal transmission cascade (GRM6, LRIT3, and TRPM1) are correctly localized, other proteins (RGS7, RGS11, and GNB5) known to regulate GRM6 are absent at the dendritic tips of ON-bipolar cells. These results add a new model of cCSNB, which is important to better understand the role of GPR179, its implication in patients with cCSNB, and its use for the development of therapies.
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Affiliation(s)
- Elise Orhan
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
| | - Marion Neuillé
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
| | - Miguel de Sousa Dias
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
| | - Thomas Pugliese
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
| | - Christelle Michiels
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
| | - Christel Condroyer
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
| | - Aline Antonio
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
| | - José-Alain Sahel
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC1423, F-75012 Paris, France
- Fondation Ophtalmologique Adolphe de Rothschild, F-75019 Paris, France
- Academie des Sciences, Institut de France, F-75006 Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Isabelle Audo
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC1423, F-75012 Paris, France
- Institute of Ophthalmology, University College of London, London EC1V 9EL, UK
| | - Christina Zeitz
- Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, F-75012 Paris, France; (E.O.); (M.N.); (M.d.S.D.); (T.P.); (C.M.); (C.C.); (A.A.); (J.-A.S.); (I.A.)
- Correspondence: ; Tel.: +33-1-53-46-25-40
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18
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Hayashi T, Murakami Y, Mizobuchi K, Koyanagi Y, Sonoda KH, Nakano T. Complete congenital stationary night blindness associated with a novel NYX variant (p.Asn216Lys) in middle-aged and older adult patients. Ophthalmic Genet 2021; 42:412-419. [PMID: 33769208 DOI: 10.1080/13816810.2021.1904422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Complete congenital stationary night blindness (CSNB) is a retinal disorder thought to be non-progressive. The purpose of this study was to characterize the clinical and genetic findings of middle-aged and older adult patients with X-linked complete CSNB. METHODS Three male CSNB patients (aged 62, 72, and 51 years) and one unaffected female carrier in a Japanese family were included in this study. Whole-exome sequencing (WES) was performed to determine the disease-causing variants. Co-segregation was confirmed in the family members. We performed a comprehensive ophthalmic examination on each patient. RESULTS In the 62-year-old patient, a novel hemizygous variant (c.648 C > A; p.Asn216Lys) of the NYX gene was identified by WES analysis. The other two patients carried the variant hemizygously, and the unaffected carrier harbored the variant heterozygously. The clinical and electroretinography (ERG) findings were very similar among all three patients. Fundus images exhibited high myopic chorioretinal atrophy with long axial length. Ultra-wide field fundus autofluorescence images showed no retinal degenerative changes except for changes resulting from high myopia and previous retinal diseases. The ERG findings showed no response in rod ERG, electronegative configuration with preserved a-waves in standard/bright-flash ERG, and preserved responses in cone and 30-Hz flicker ERG, which were compared with age-matched controls with high myopia. CONCLUSIONS We identified a novel missense NYX variant in a Japanese family with complete CSNB. Our clinical findings indicated that photoreceptor mediated ERG responses are well preserved even in middle-aged and older adult patients.
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Affiliation(s)
- 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
| | - Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Yoshito Koyanagi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
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19
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Varin J, Bouzidi N, Dias MMDS, Pugliese T, Michiels C, Robert C, Desrosiers M, Sahel JA, Audo I, Dalkara D, Zeitz C. Restoration of mGluR6 Localization Following AAV-Mediated Delivery in a Mouse Model of Congenital Stationary Night Blindness. Invest Ophthalmol Vis Sci 2021; 62:24. [PMID: 33729473 PMCID: PMC7980044 DOI: 10.1167/iovs.62.3.24] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Complete congenital stationary night blindness (cCSNB) is an incurable inherited retinal disorder characterized by an ON-bipolar cell (ON-BC) defect. GRM6 mutations are the third most prevalent cause of cCSNB. The Grm6-/- mouse model mimics the human phenotype, showing no b-wave in the electroretinogram (ERG) and a loss of mGluR6 and other proteins of the same cascade at the outer plexiform layer (OPL). Our aim was to restore protein localization and function in Grm6-/- adult mice targeting specifically ON-BCs or the whole retina. Methods Adeno-associated virus-encoding Grm6 under two different promoters (GRM6-Grm6 and CAG-Grm6) were injected intravitreally in P15 Grm6-/- mice. ERG recordings at 2 and 4 months were performed in Grm6+/+, untreated and treated Grm6-/- mice. Similarly, immunolocalization studies were performed on retinal slices before or after treatment using antibodies against mGluR6, TRPM1, GPR179, RGS7, RGS11, Gβ5, and dystrophin. Results Following treatment, mGluR6 was localized to the dendritic tips of ON-BCs when expressed with either promoter. The relocalization efficiency in mGluR6-transduced retinas at the OPL was 2.5% versus 11% when the GRM6-Grm6 and CAG-Grm6 were used, respectively. Albeit no functional rescue was seen in ERGs, relocalization of TRPM1, GPR179, and Gβ5 was also noted using both constructs. The restoration of the localization of RGS7, RGS11, and dystrophin was more obvious in retinas treated with GRM6-Grm6 than in retinas treated with CAG-Grm6. Conclusions Our findings show the potential of treating cCSNB with GRM6 mutations; however, it appears that the transduction rate must be improved to restore visual function.
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Affiliation(s)
- Juliette Varin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Nassima Bouzidi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Thomas Pugliese
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Camille Robert
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, Paris, France.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Academie des Sciences, Institut de France, Paris, France.,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, United Kingdom
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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20
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Delle Fave M, Cordonnier M, Vallee L, Condroyer C, Zeitz C, Balikova I. Congenital stationary night blindness in a patient with mild learning disability due to a compound heterozygous microdeletion of 15q13 and a missense mutation in TRPM1. Ophthalmic Genet 2021; 42:296-299. [PMID: 33691579 DOI: 10.1080/13816810.2021.1897846] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The complete form of congenital stationary night blindness (cCSNB) represents a non-progressive retinal disorder characterized by night vision problems and often congenital nystagmus, reduced vision, high myopia, strabismus and normal fundus appearance. Clinically this form of CSNB can be diagnosed by full-field electroretinogram. The mode of inheritance can be X-linked and autosomal recessive with mutations in genes coding for proteins mainly present at the dendritic tips of ON-bipolar cells. Mutations in NYX, GRM6, GPR179, LRIT3 and TRPM1 lead to this condition. The latter gene defect represents the major form underlying cCSNBC. It codes for the melastatin-related transient receptor 1 expressed in the inner nuclear layer of the retina, with the protein localized in ON-bipolar cells. To date, various homozygous or compound heterozygous mutations in TRPM1 have been reported. Small chromosomal rearrangements are frequent cause of mental retardation. In rare cases deletions can overlap with a mutation on the remaining chromosome and lead to a recessive disorder. Here, we describe a patient with mild neurological deficiencies and cCSNB caused by a microdeletion on 15q32 overlapping with a TRPM1 variant.
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Affiliation(s)
- M Delle Fave
- Ophthalmology Service, CUB Hopital Erasme, Brussels, Belgium
| | - M Cordonnier
- Ophthalmology Service, CUB Hopital Erasme, Brussels, Belgium
| | - L Vallee
- Neuropediatric Service, University Hospital Lille, Lille, France
| | - C Condroyer
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - C Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - I Balikova
- Ophthalmology Service, University Hospital Gasthuisberg, Leuven, Belgium
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21
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Rai D, Akagi T, Shimohata A, Ishii T, Gangi M, Maruyama T, Wada-Kiyama Y, Ogiwara I, Kaneda M. Involvement of the C-terminal domain in cell surface localization and G-protein coupling of mGluR6. J Neurochem 2020; 158:837-848. [PMID: 33067823 DOI: 10.1111/jnc.15217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 05/25/2020] [Accepted: 10/11/2020] [Indexed: 01/05/2023]
Abstract
Metabotropic glutamate receptor 6, mGluR6, interacts with scaffold proteins and Gβγ subunits via its intracellular C-terminal domain (CTD). The mGluR6 pathway is critically involved in the retinal processing of visual signals. We herein investigated whether the CTD (residues 840-871) was necessary for mGluR6 cell surface localization and G-protein coupling using mGluR6-CTD mutants with immunocytochemistry, surface biotinylation assays, and electrophysiological approaches. We used 293T cells and primary hippocampal neurons as model systems. We examined C-terminally truncated mGluR6 and showed that the removal of up to residue 858 did not affect surface localization or glutamate-induced G-protein-mediated responses, whereas a 15-amino acid deletion (Δ857-871) impaired these functions. However, a 21-amino acid deletion (Δ851-871) restored surface localization and glutamate-dependent responses, which were again attenuated when the entire CTD was removed. The sequence alignment of group III mGluRs showed conserved amino acids resembling an ER retention motif in the CTD. These results suggest that the intracellular CTD is required for the cell surface transportation and receptor function of mGluR6, whereas it may contain regulatory elements for intracellular trafficking and signaling.
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Affiliation(s)
- Dilip Rai
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Takumi Akagi
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | | | - Toshiyuki Ishii
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Mie Gangi
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Takuma Maruyama
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | | | - Ikuo Ogiwara
- Department of Physiology, Nippon Medical School, Tokyo, Japan
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22
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Hayashi T, Mizobuchi K, Kikuchi S, Nakano T. Novel biallelic TRPM1 variants in an elderly patient with complete congenital stationary night blindness. Doc Ophthalmol 2020; 142:265-273. [PMID: 33068213 DOI: 10.1007/s10633-020-09798-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/01/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Little is known about whether patients with complete congenital stationary night blindness (CSNB) maintain visual function throughout their lifetime. The purpose of this report was to describe clinical and genetic features of an elderly female patient with complete CSNB that we followed for 5 years. METHODS Molecular genetic analysis using whole-exome sequencing (WES) was performed to detect disease-causing variants. We performed a comprehensive ophthalmic examination including full-field electroretinography (ERG). RESULTS In the patient, WES identified two novel variants (c.1034delT; p.Phe345SerfsTer16 and c.1880T>A; p.Met627Lys) in the TRPM1 gene. Her unaffected daughter has one of the variants. The patient reported that her visual acuity has remained unchanged since elementary school. At the age of 68 years old, fundus and fundus autofluorescence imaging showed no remarkable findings except for mild myopic changes. Goldmann perimetry showed preserved visual fields with all V-4e, I-4e, I-3e and I-2e isopters. Optical coherence tomography demonstrated preserved retinal thickness and lamination. Rod ERG showed no response; bright-flash ERG showed an electronegative configuration with minimally reduced a-waves, and cone and 30-Hz flicker ERG showed minimally reduced responses. Overall, the ERG findings of ON bipolar pathway dysfunction were consistent with complete CSNB. CONCLUSIONS This is the oldest reported patient with complete CSNB and biallelic TRPM1 variants. Our ophthalmic findings suggest that some patients with TRPM1-related CSNB may exhibit preserved retinal function later in life.
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Affiliation(s)
- Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, 105-8461, Japan. .,Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, 6-41-2 Aoto, Katsushika-ku, Tokyo, 125-8506, Japan.
| | - Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, 105-8461, Japan
| | - Shinsuke Kikuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, 105-8461, Japan.,Kikuchi Eye Clinic, Tokyo, 192-0904, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, 105-8461, Japan
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23
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Hack YL, Crabtree EE, Avila F, Sutton RB, Grahn R, Oh A, Gilger B, Bellone RR. Whole-genome sequencing identifies missense mutation in GRM6 as the likely cause of congenital stationary night blindness in a Tennessee Walking Horse. Equine Vet J 2020; 53:316-323. [PMID: 32654228 DOI: 10.1111/evj.13318] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/01/2020] [Accepted: 06/25/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND The only known genetic cause of congenital stationary night blindness (CSNB) in horses is a 1378 bp insertion in TRPM1. However, an affected Tennessee Walking Horse was found to have no copies of this variant. OBJECTIVES To identify the genetic cause for CSNB in an affected Tennessee Walking Horse. STUDY DESIGN Case report detailing a whole-genome sequencing (WGS) approach to identify a causal variant. METHODS A complete ophthalmic exam, including an electroretinogram (ERG), was performed on suspected CSNB-affected horse. WGS data were generated from the case and compared with data from seven other breeds (n = 29). One hundred candidate genes were evaluated for coding variants homozygous in the case and absent in all other horses. Protein modelling was used to assess the functional effects of the identified variant. A random cohort of 90 unrelated Tennessee Walking Horses and 273 horses from additional breeds were screened to estimate allele frequency of the GRM6 variant. RESULTS ERG results were consistent with CSNB. WGS analysis identified a missense mutation in metabotropic glutamate receptor 6 (GRM6) (c.533C>T p.Thr178Met). This single nucleotide polymorphism (SNP) is predicted to be deleterious and protein modelling supports impaired binding of the neurotransmitter glutamate. This variant was not detected in 273 horses from three additional breeds. The estimated allele frequency in Tennessee Walking Horses is 10%. MAIN LIMITATIONS Limited phenotype information for controls and no additional cases with which to replicate this finding. CONCLUSIONS We identified a likely causal recessive missense variant in GRM6. Based on protein modelling, this variant alters GRM6 binding, and thus signalling from the retinal rod cell to the ON-bipolar cell, impairing vision in low light conditions. Given the 10% population allele frequency, it is likely that additional affected horses exist in this breed and further work is needed to identify and examine these animals.
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Affiliation(s)
- Yael L Hack
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Elizabeth E Crabtree
- College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Felipe Avila
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Roger B Sutton
- Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Robert Grahn
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Annie Oh
- College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Brian Gilger
- College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Rebecca R Bellone
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, California, USA.,Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California, USA
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24
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Varin J, Reynolds MM, Bouzidi N, Tick S, Wohlschlegel J, Becquart O, Michiels C, Dereure O, Duvoisin RM, Morgans CW, Sahel JA, Samaran Q, Guillot B, Pulido JS, Audo I, Zeitz C. Identification and characterization of novel TRPM1 autoantibodies from serum of patients with melanoma-associated retinopathy. PLoS One 2020; 15:e0231750. [PMID: 32324760 PMCID: PMC7179873 DOI: 10.1371/journal.pone.0231750] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/31/2020] [Indexed: 12/15/2022] Open
Abstract
Melanoma-associated retinopathy (MAR) is a rare paraneoplastic retinal disorder usually occurring in the context of metastatic melanoma. Patients present with night blindness, photopsias and a constriction of the visual field. MAR is an auto-immune disorder characterized by the production of autoantibodies targeting retinal proteins, especially autoantibodies reacting to the cation channel TRPM1 produced in melanocytes and ON-bipolar cells. TRPM1 has at least three different isoforms which vary in the N-terminal region of the protein. In this study, we report the case of three new MAR patients presenting different anti-TRPM1 autoantibodies reacting to the three isoforms of TRPM1 with variable binding affinity. Two sera recognized all isoforms of TRPM1, while one recognized only the two longest isoforms upon immunolocalization studies on overexpressing cells. Similarly, the former two sera reacted with all TRPM1 isoforms on western blot, but an immunoprecipitation enrichment step was necessary to detect all isoforms with the latter serum. In contrast, all sera labelled ON-bipolar cells on Tprm1+/+ but not on Trpm1-/- mouse retina as shown by co-immunolocalization. This confirms that the MAR sera specifically detect TRPM1. Most likely, the anti-TRPM1 autoantibodies of different patients vary in affinity and concentration. In addition, the binding of autoantibodies to TRPM1 may be conformation-dependent, with epitopes being inaccessible in some constructs (truncated polypeptides versus full-length TRPM1) or applications (western blotting versus immunohistochemistry). Therefore, we propose that a combination of different methods should be used to test for the presence of anti-TRPM1 autoantibodies in the sera of MAR patients.
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Affiliation(s)
- Juliette Varin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Margaret M. Reynolds
- Department of Ophthalmology, Washington University, Saint Louis, MO, United States of America
| | - Nassima Bouzidi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Sarah Tick
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, Paris, France
| | | | - Ondine Becquart
- Department of Dermatology and INSERM U1058 “Pathogenesis and control of chronic infections”, University of Montpellier, Montpellier, France
| | | | - Olivier Dereure
- Department of Dermatology and INSERM U1058 “Pathogenesis and control of chronic infections”, University of Montpellier, Montpellier, France
| | - Robert M. Duvoisin
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, United States of America
| | - Catherine W. Morgans
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, United States of America
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, Paris, France
- Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
- Académie des Sciences, Institut de France, Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Quentin Samaran
- Department of Dermatology and INSERM U1058 “Pathogenesis and control of chronic infections”, University of Montpellier, Montpellier, France
| | - Bernard Guillot
- Department of Dermatology and INSERM U1058 “Pathogenesis and control of chronic infections”, University of Montpellier, Montpellier, France
| | - José S. Pulido
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, Paris, France
- Institute of Ophthalmology, University College of London, London, United Kingdom
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- * E-mail:
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25
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Furukawa T, Ueno A, Omori Y. Molecular mechanisms underlying selective synapse formation of vertebrate retinal photoreceptor cells. Cell Mol Life Sci 2020; 77:1251-1266. [PMID: 31586239 PMCID: PMC11105113 DOI: 10.1007/s00018-019-03324-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/21/2019] [Accepted: 09/25/2019] [Indexed: 11/29/2022]
Abstract
In vertebrate central nervous systems (CNSs), highly diverse neurons are selectively connected via synapses, which are essential for building an intricate neural network. The vertebrate retina is part of the CNS and is comprised of a distinct laminar organization, which serves as a good model system to study developmental synapse formation mechanisms. In the retina outer plexiform layer, rods and cones, two types of photoreceptor cells, elaborate selective synaptic contacts with ON- and/or OFF-bipolar cell terminals as well as with horizontal cell terminals. In the mouse retina, three photoreceptor subtypes and at least 15 bipolar subtypes exist. Previous and recent studies have significantly progressed our understanding of how selective synapse formation, between specific subtypes of photoreceptor and bipolar cells, is designed at the molecular level. In the ON pathway, photoreceptor-derived secreted and transmembrane proteins directly interact in trans with the GRM6 (mGluR6) complex, which is localized to ON-bipolar cell dendritic terminals, leading to selective synapse formation. Here, we review our current understanding of the key factors and mechanisms underlying selective synapse formation of photoreceptor cells with bipolar and horizontal cells in the retina. In addition, we describe how defects/mutations of the molecules involved in photoreceptor synapse formation are associated with human retinal diseases and visual disorders.
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Affiliation(s)
- Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Akiko Ueno
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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26
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Liang Q, Dharmat R, Owen L, Shakoor A, Li Y, Kim S, Vitale A, Kim I, Morgan D, Liang S, Wu N, Chen K, DeAngelis MM, Chen R. Single-nuclei RNA-seq on human retinal tissue provides improved transcriptome profiling. Nat Commun 2019; 10:5743. [PMID: 31848347 PMCID: PMC6917696 DOI: 10.1038/s41467-019-12917-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 10/02/2019] [Indexed: 12/23/2022] Open
Abstract
Single-cell RNA-seq is a powerful tool in decoding the heterogeneity in complex tissues by generating transcriptomic profiles of the individual cell. Here, we report a single-nuclei RNA-seq (snRNA-seq) transcriptomic study on human retinal tissue, which is composed of multiple cell types with distinct functions. Six samples from three healthy donors are profiled and high-quality RNA-seq data is obtained for 5873 single nuclei. All major retinal cell types are observed and marker genes for each cell type are identified. The gene expression of the macular and peripheral retina is compared to each other at cell-type level. Furthermore, our dataset shows an improved power for prioritizing genes associated with human retinal diseases compared to both mouse single-cell RNA-seq and human bulk RNA-seq results. In conclusion, we demonstrate that obtaining single cell transcriptomes from human frozen tissues can provide insight missed by either human bulk RNA-seq or animal models.
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Affiliation(s)
- Qingnan Liang
- HGSC, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, 77030, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Rachayata Dharmat
- HGSC, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, 77030, TX, USA
- St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN, 38105, USA
| | - Leah Owen
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA
| | - Akbar Shakoor
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA
| | - Yumei Li
- HGSC, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Sangbae Kim
- HGSC, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Albert Vitale
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA
| | - Ivana Kim
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA
| | - Denise Morgan
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA
- Department of Pharmacotherapy, the College of Pharmacy, University of Utah, Salt Lake City, UT, 84132, USA
| | - Shaoheng Liang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Nathaniel Wu
- HGSC, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ken Chen
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Margaret M DeAngelis
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA.
- Department of Pharmacotherapy, the College of Pharmacy, University of Utah, Salt Lake City, UT, 84132, USA.
- Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA.
| | - Rui Chen
- HGSC, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, 77030, TX, USA.
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
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27
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Liu HY, Huang J, Xiao H, Zhang MJ, Shi FF, Jiang YH, Du H, He Q, Wang ZY. Pseudodominant inheritance of autosomal recessive congenital stationary night blindness in one family with three co-segregating deleterious GRM6 variants identified by next-generation sequencing. Mol Genet Genomic Med 2019; 7:e952. [PMID: 31677249 PMCID: PMC6900388 DOI: 10.1002/mgg3.952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The congenital stationary night blindness (CSNB) affects the patients' dim light vision or dark adaption by impairing the normal function of retina. It is a clinically and genetically heterogeneous disorder and can be inherited in an X-linked, autosomal dominant or autosomal recessive pattern. Several genetic alterations to the genes involved in visual signal transduction of photoreceptors and/or bipolar cells underlie its pathogenesis. METHODS In this study, we used Sanger sequencing and next-generation sequencing (NGS)-based gene panel screening to investigate a family of three patients with CSNB inherited in an apparent autosomal dominant pattern. We expected to find out the disease-causing gene defects carried by this family. RESULTS We found that the patients in this family did not carry the RHO, GNAT1, or PDE6B mutation, but carried compound heterozygotes mutations of GRM6. Three deleterious GRM6 variants, p.Arg621Ter, p.Gly51Val, and p.Gly464Arg, were found to be co-segregating with the disease, causing a pseudodominant inheritance of GRM6-related autosomal recessive complete CSNB. CONCLUSION This study presents a rare case of autosomal recessive CSNB (arCSNB) pseudodominant inheritance, which potentially leads us to expand our gene candidate list in future genetic testing for apparent dominant pedigrees. The discovery of the two novel likely pathogenic variants p.Gly51Val and p.Gly464Arg could broaden our knowledge about the genetics of CSNB and provide insights into the structure and function of the GRM6 protein.
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Affiliation(s)
- Hong-Yan Liu
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Jia Huang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Hai Xiao
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Ming-Jie Zhang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Fei-Fei Shi
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Ying-Hai Jiang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Han Du
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
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A founder deletion in the TRPM1 gene associated with congenital stationary night blindness and myopia is highly prevalent in Ashkenazi Jews. Hum Genome Var 2019; 6:45. [PMID: 31645983 PMCID: PMC6804618 DOI: 10.1038/s41439-019-0076-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 02/07/2023] Open
Abstract
Congenital stationary night blindness (CSNB) is a disease affecting the night vision of individuals. Previous studies identified TRPM1 as a gene involved in reduced night vision. Homozygous deletion of TRPM1 was the cause of CSNB in several children in 6 Ashkenazi Jewish families, thereby prompting further investigation of the carrier status within the families as well as in large cohorts of unrelated Ashkenazi and Sephardi individuals. Affected children were tested with a CSNB next-generation (NextGen) sequencing panel. A deletion of TRPM1 exons 2 through 7 was detected and confirmed by PCR and sequence analysis. A TaqMan-based assay was used to assess the frequency of this deletion in 18266 individuals of Jewish descent. High-throughput amplicon sequencing was performed on 380 samples to determine the putative deletion-flanking founder haplotype. Heterozygous TRPM1 deletions were found in 2.75% (1/36) of Ashkenazi subjects and in 1.22% (1/82) individuals of mixed Ashkenazi/Sephardic origin. The homozygous deletion frequency in our data was 0.03% (1/4025) and was only found in Ashkenazi Jewish individuals. Homozygous deletion of exons 2–7 in TRPM1 is a common cause of CSNB and myopia in many Ashkenazi Jewish patients. This deletion is a founder Ashkenazi Jewish deletion. A genetic mutation found in Ashkenazi Jewish population causes an eye disease that leads to poor vision in dim light. Yoel Hirsch and Martin M. Johansson from Dor Yeshorim, together with colleagues determined the genetic etiology of congenital stationary night blindness (CSNB) in children from six Ashkenazi families. Each affected child harbored two mutant versions of TRPM1, a gene involved in the transmission of light-elicited signals within the retina of the eye. Notably, all the children had the same large chunk of DNA missing from the gene. The researchers next screened for this genetic deletion in >18,000 individuals of Jewish descent, finding single copies of the mutation in 2.75% of Ashkenazi subjects. The findings should help doctors better diagnose CSNB and care for Jewish patients with eyesight problems.
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Wu KC, Chen XJ, Jin GH, Wang XY, Yang DD, Li YP, Xiang L, Zhang BW, Zhou GH, Zhang CJ, Jin ZB. Deletion of miR-182 Leads to Retinal Dysfunction in Mice. Invest Ophthalmol Vis Sci 2019; 60:1265-1274. [PMID: 30924851 DOI: 10.1167/iovs.18-24166] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose MicroRNA-182 (miR-182) is abundantly expressed in mammalian retinas; however, the association between miR-182 and retinal function remains unclear. In this study, we explored whether miR-182 contributes to functional decline in retinas using a miR-182 depleted mouse. Methods Electroretinogram (ERG) amplitudes at different ages were measured in miR-182 knockout (KO) mice. The thickness and lamination of retinas were assessed using a color fundus camera and high-resolution optical coherence tomography. Expression levels of key photoreceptor-specific genes and the miR-183/96/182 cluster (miR-183C) were quantified using quantitative real-time PCR. RNA sequencing and light-induced damage were carried out to observe the changes in the retinal transcriptome and sensitivity to light damage in the miR-182 KO mice. Results The ERG recording reveals that the ERG response amplitude decreased both at early and later ages when compared with control littermates. The expression of some key photoreceptor-specific genes was down-regulated with deletion of miR-182 in retina. RNA sequencing indicated that some biological processes of visual system were affected, and the numbers of potential target genes of miR-182 were presented in the mouse retina using bioinformatics analysis. The miR-182 KO mice were characterized by progressively losing the outer segment after being treated with light-damage exposure. The thickness and lamination of retina as well as compensatory expression of miR-183C showed no apparent changes in retina of miR-182 KO mice under normal laboratory lighting condition. Conclusions Our findings provided new insights into the relationship between the miR-182 and retinal development and revealed that miR-182 may play a critical role in maintaining retinal function.
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Affiliation(s)
- Kun-Chao Wu
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xue-Jiao Chen
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Guang-Hui Jin
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xiao-Yun Wang
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Dan-Dan Yang
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yan-Ping Li
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Lue Xiang
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Bo-Wen Zhang
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Gao-Hui Zhou
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Chang-Jun Zhang
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zi-Bing Jin
- Lab for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, State Key Laboratory of Ophthalmology, Optometry and Vision Science, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
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Abstract
The transient receptor potential channel TRPM1 is required for synaptic transmission between photoreceptors and the ON subtype of bipolar cells (ON-BPC), mediating depolarization in response to light. TRPM1 is present in the somas and postsynaptic dendritic tips of ON-BPCs. Monoclonal antibodies generated against full-length TRPM1 were found to have differential labeling patterns when used to immunostain the mouse retina, with some yielding reduced labeling of dendritic tips relative to the labeling of cell bodies. Epitope mapping revealed that those antibodies that poorly label the dendritic tips share a binding site (N2d) in the N-terminal arm near the transmembrane domain. A major splice variant of TRPM1 lacking exon 19 does not contain the N2d binding site, but quantitative immunoblotting revealed no enrichment of this variant in synaptsomes. One explanation of the differential labeling is masking of the N2d epitope by formation of a synapse-specific multiprotein complex. Identifying the binding partners that are specific for the fraction of TRPM1 present at the synapses is an ongoing challenge for understanding TRPM1 function.
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Harmonics added to a flickering light can upset the balance between ON and OFF pathways to produce illusory colors. Proc Natl Acad Sci U S A 2018; 115:E4081-E4090. [PMID: 29632212 PMCID: PMC5924891 DOI: 10.1073/pnas.1717356115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
By varying the temporal waveforms of complex flickering stimuli, we can produce alterations in their mean color that can be predicted by a physiologically based model of visual processing. The model highlights the perceptual effects of a well-known feature of most visual pathways, namely the early separation of visual signals into increments and decrements. The role of this separation in improving the efficiency and sensitivity of the visual system has been discussed before, but its effect on perception has been neglected. The application of a model incorporating half-wave rectification offers an exciting psychophysical method for investigating the inner workings of the human visual system. The neural signals generated by the light-sensitive photoreceptors in the human eye are substantially processed and recoded in the retina before being transmitted to the brain via the optic nerve. A key aspect of this recoding is the splitting of the signals within the two major cone-driven visual pathways into distinct ON and OFF branches that transmit information about increases and decreases in the neural signal around its mean level. While this separation is clearly important physiologically, its effect on perception is unclear. We have developed a model of the ON and OFF pathways in early color processing. Using this model as a guide, we can produce imbalances in the ON and OFF pathways by changing the shapes of time-varying stimulus waveforms and thus make reliable and predictable alterations to the perceived average color of the stimulus—although the physical mean of the waveforms does not change. The key components in the model are the early half-wave rectifying synapses that split retinal photoreceptor outputs into the ON and OFF pathways and later sigmoidal nonlinearities in each pathway. The ability to systematically vary the waveforms to change a perceptual quality by changing the balance of signals between the ON and OFF visual pathways provides a powerful psychophysical tool for disentangling and investigating the neural workings of human vision.
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32
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Abstract
Cacna1s encodes the α1S subunit (Cav1.1) of voltage-dependent calcium channels, and is required for normal skeletal and cardiac muscle function, where it couples with the ryanodine receptor to regulate muscle contraction. Recently CACNA1S was reported to be expressed on the tips of retinal depolarizing bipolar cells (DBCs) and colocalized with metabotropic glutamate receptor 6 (mGluR6), which is critical to DBC signal transduction. Further, in mGluR6 knockout mice, expression at this location is down regulated. We examined RNAseq data from mouse retina and found expression of a novel isoform of Cacna1s. To determine if CACNA1S was a functional component of the DBC signal transduction cascade, we performed immunohistochemistry to visualize its expression in several mouse lines that lack DBC function. Immunohistochemical staining with antibodies to CACNA1S show punctate labeling at the tips of DBCs in wild type (WT) retinas that are absent in Gpr179 nob5 mutant retinas and decreased in Grm6 -/- mouse retinas. CACNA1S and transient receptor potential cation channel, subfamily M, member 1 (TRPM1) staining also colocalized in WT retinas. Western blot analyses for CACNA1S of either retinal lysates or proteins after immunoprecipitation with the CACNA1S antibody failed to show the presence of bands expected for CACNA1S. Mass spectrometric analysis of CACNA1S immunoprecipitated proteins also failed to detect any peptides matching CACNA1S. Immunohistochemistry and western blotting after expression of GPR179 in HEK293T cells indicate that the CACNA1S antibody used here and in the retinal studies published to date, cross-reacts with GPR179. These data suggest caution should be exercised in conferring a role for CACNA1S in DBC signal transduction based solely on immunohistochemical staining.
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33
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Peachey NS, Hasan N, FitzMaurice B, Burrill S, Pangeni G, Karst SY, Reinholdt L, Berry ML, Strobel M, Gregg RG, McCall MA, Chang B. A missense mutation in Grm6 reduces but does not eliminate mGluR6 expression or rod depolarizing bipolar cell function. J Neurophysiol 2017; 118:845-854. [PMID: 28490646 DOI: 10.1152/jn.00888.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 05/03/2017] [Accepted: 05/03/2017] [Indexed: 01/01/2023] Open
Abstract
GRM6 encodes the metabotropic glutamate receptor 6 (mGluR6) used by retinal depolarizing bipolar cells (DBCs). Mutations in GRM6 lead to DBC dysfunction and underlie the human condition autosomal recessive complete congenital stationary night blindness. Mouse mutants for Grm6 are important models for this condition. Here we report a new Grm6 mutant, identified in an electroretinogram (ERG) screen of mice maintained at The Jackson Laboratory. The Grm6nob8 mouse has a reduced-amplitude b-wave component of the ERG, which reflects light-evoked DBC activity. Sequencing identified a missense mutation that converts a highly conserved methionine within the ligand binding domain to leucine (p.Met66Leu). Consistent with prior studies of Grm6 mutant mice, the laminar size and structure in the Grm6nob8 retina were comparable to control. The Grm6nob8 phenotype is distinguished from other Grm6 mutants that carry a null allele by a reduced but not absent ERG b-wave, decreased but present expression of mGluR6 at DBC dendritic tips, and mislocalization of mGluR6 to DBC somas. Consistent with a reduced but not absent b-wave, there were a subset of retinal ganglion cells whose responses to light onset have times to peak within the range of those in control retinas. These data indicate that the p.Met66Leu mutant mGluR6 is trafficked less than control. However, the mGluR6 that is localized to the DBC dendritic tips is able to initiate DBC signal transduction. The Grm6nob8 mouse extends the Grm6 allelic series and will be useful for elucidating the role of mGluR6 in DBC signal transduction and in human disease.NEW & NOTEWORTHY This article describes a mouse model of the human disease complete congenital stationary night blindness in which the mutation reduces but does not eliminate GRM6 expression and bipolar cell function, a distinct phenotype from that seen in other Grm6 mouse models.
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Affiliation(s)
- Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio.,Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio.,Department of Ophthalmology, Cleveland Clinic College of Medicine of Case Western Reserve University, Cleveland, Ohio
| | - Nazarul Hasan
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, Kentucky
| | | | | | - Gobinda Pangeni
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky; and
| | | | | | | | | | - Ronald G Gregg
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, Kentucky.,Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky; and
| | - Maureen A McCall
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky; and.,Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine;
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Glasauer SMK, Wäger R, Gesemann M, Neuhauss SCF. mglur6b:EGFP Transgenic zebrafish suggest novel functions of metabotropic glutamate signaling in retina and other brain regions. J Comp Neurol 2016; 524:2363-78. [PMID: 27121676 DOI: 10.1002/cne.24029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/21/2016] [Accepted: 04/21/2016] [Indexed: 02/04/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are mainly known for regulating excitability of neurons. However, mGluR6 at the photoreceptor-ON bipolar cell synapse mediates sign inversion through glutamatergic inhibition. Although this is currently the only confirmed function of mGluR6, other functions have been suggested. Here we present Tg(mglur6b:EGFP)zh1, a new transgenic zebrafish line recapitulating endogenous expression of one of the two mglur6 paralogs in zebrafish. Investigating transgene as well as endogenous mglur6b expression within the zebrafish retina indicates that EGFP and mglur6b mRNA are not only expressed in bipolar cells, but also in a subset of ganglion and amacrine cells. The amacrine cells labeled in Tg(mglur6b:EGFP)zh1 constitute a novel cholinergic, non-GABAergic, non-starburst amacrine cell type described for the first time in teleost fishes. Apart from the retina, we found transgene expression in subsets of periventricular neurons of the hypothalamus, Purkinje cells of the cerebellum, various cell types of the optic tectum, and mitral/ruffed cells of the olfactory bulb. These findings suggest novel functions of mGluR6 besides sign inversion at ON bipolar cell dendrites, opening up the possibility that inhibitory glutamatergic signaling may be more prevalent than currently thought. J. Comp. Neurol. 524:2363-2378, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Stella M K Glasauer
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland.,Life Science Zurich Graduate School, Ph.D. Program in Molecular Life Sciences, Zurich, Switzerland
| | - Robert Wäger
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland
| | - Matthias Gesemann
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland
| | - Stephan C F Neuhauss
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland.,Life Science Zurich Graduate School, Ph.D. Program in Molecular Life Sciences, Zurich, Switzerland
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35
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Identification of a new mutant allele, Grm6(nob7), for complete congenital stationary night blindness. Vis Neurosci 2016; 32:E004. [PMID: 26241901 DOI: 10.1017/s0952523815000012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Electroretinogram (ERG) studies identified a new mouse line with a normal a-wave but lacking the b-wave component. The ERG phenotype of this new allele, nob7, matched closely that of mouse mutants for Grm6, Lrit3, Trpm1, and Nyx, which encode for proteins expressed in depolarizing bipolar cells (DBCs). To identify the underlying mutation, we first crossed nob7 mice with Grm6 nob3 mutants and measured the ERGs in offspring. All the offspring lacked the b-wave, indicating that nob7 is a new allele for Grm6: Grm6 nob7 . Sequence analyses of Grm6 nob7 cDNAs identified a 28 base pair insertion between exons 8 and 9, which would result in a frameshift mutation in the open reading frame that encodes the metabotropic glutamate receptor 6 (Grm6). Sequencing both the cDNA and genomic DNA from exon 8 and intron 8, respectively, from the Grm6 nob7 mouse revealed a G to A transition at the last position in exon 8. This mutation disrupts splicing and the normal exon 8 is extended by 28 base pairs, because splicing occurs 28 base pairs downstream at a cryptic splice donor. Consistent with the impact of the resulting frameshift mutation, there is a loss of mGluR6 protein (encoded by Grm6) from the dendritic tips of DBCs in the Grm6 nob7 retina. These results indicate that Grm6 nob7 is a new model of the complete form of congenital stationary night blindness, a human condition that has been linked to mutations of GRM6.
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36
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Jones BW, Pfeiffer RL, Ferrell WD, Watt CB, Marmor M, Marc RE. Retinal remodeling in human retinitis pigmentosa. Exp Eye Res 2016; 150:149-65. [PMID: 27020758 DOI: 10.1016/j.exer.2016.03.018] [Citation(s) in RCA: 208] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 02/23/2016] [Accepted: 03/18/2016] [Indexed: 12/11/2022]
Abstract
Retinitis Pigmentosa (RP) in the human is a progressive, currently irreversible neural degenerative disease usually caused by gene defects that disrupt the function or architecture of the photoreceptors. While RP can initially be a disease of photoreceptors, there is increasing evidence that the inner retina becomes progressively disorganized as the outer retina degenerates. These alterations have been extensively described in animal models, but remodeling in humans has not been as well characterized. This study, using computational molecular phenotyping (CMP) seeks to advance our understanding of the retinal remodeling process in humans. We describe cone mediated preservation of overall topology, retinal reprogramming in the earliest stages of the disease in retinal bipolar cells, and alterations in both small molecule and protein signatures of neurons and glia. Furthermore, while Müller glia appear to be some of the last cells left in the degenerate retina, they are also one of the first cell classes in the neural retina to respond to stress which may reveal mechanisms related to remodeling and cell death in other retinal cell classes. Also fundamentally important is the finding that retinal network topologies are altered. Our results suggest interventions that presume substantial preservation of the neural retina will likely fail in late stages of the disease. Even early intervention offers no guarantee that the interventions will be immune to progressive remodeling. Fundamental work in the biology and mechanisms of disease progression are needed to support vision rescue strategies.
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Affiliation(s)
- B W Jones
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA.
| | - R L Pfeiffer
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
| | - W D Ferrell
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
| | - C B Watt
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
| | - M Marmor
- Dept. Ophthalmology, Stanford University, USA
| | - R E Marc
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
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37
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Neuillé M, Malaichamy S, Vadalà M, Michiels C, Condroyer C, Sachidanandam R, Srilekha S, Arokiasamy T, Letexier M, Démontant V, Sahel JA, Sen P, Audo I, Soumittra N, Zeitz C. Next-generation sequencing confirms the implication of SLC24A1 in autosomal-recessive congenital stationary night blindness. Clin Genet 2016; 89:690-9. [PMID: 26822852 DOI: 10.1111/cge.12746] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/25/2016] [Accepted: 01/25/2016] [Indexed: 01/17/2023]
Abstract
Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous retinal disorder which represents rod photoreceptor dysfunction or signal transmission defect from photoreceptors to adjacent bipolar cells. Patients displaying photoreceptor dysfunction show a Riggs-electroretinogram (ERG) while patients with a signal transmission defect show a Schubert-Bornschein ERG. The latter group is subdivided into complete or incomplete (ic) CSNB. Only few CSNB cases with Riggs-ERG and only one family with a disease-causing variant in SLC24A1 have been reported. Whole-exome sequencing (WES) in a previously diagnosed icCSNB patient identified a homozygous nonsense variant in SLC24A1. Indeed, re-investigation of the clinical data corrected the diagnosis to Riggs-form of CSNB. Targeted next-generation sequencing (NGS) identified compound heterozygous deletions and a homozygous missense variant in SLC24A1 in two other patients, respectively. ERG abnormalities varied in these three cases but all patients had normal visual acuity, no myopia or nystagmus, unlike in Schubert-Bornschein-type of CSNB. This confirms that SLC24A1 defects lead to CSNB and outlines phenotype/genotype correlations in CSNB subtypes. In case of unclear clinical characteristics, NGS techniques are helpful to clarify the diagnosis.
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Affiliation(s)
- M Neuillé
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - S Malaichamy
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - M Vadalà
- Ophthalmology Section, Department of Experimental Medicine and Clinical Neuroscience, University of Palermo, Palermo, Italy
| | - C Michiels
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - C Condroyer
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - R Sachidanandam
- Department of Optometry, Medical Research Foundation, Chennai, India
| | - S Srilekha
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - T Arokiasamy
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | | | - V Démontant
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - J-A Sahel
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, UK.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Académie des Sciences, Institut de France, Paris, France
| | - P Sen
- Department of Vitreo-Retinal Services, Medical Research Foundation, Chennai, India
| | - I Audo
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, UK
| | - N Soumittra
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - C Zeitz
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
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Romano MR, Di Menna L, Scarselli P, Mascio G, Madonna M, Notartomaso S, Puliti A, Bruno V, Battaglia G, Nicoletti F. Type-1, but Not Type-5, Metabotropic Glutamate Receptors are Coupled to Polyphosphoinositide Hydrolysis in the Retina. Neurochem Res 2015; 41:924-32. [DOI: 10.1007/s11064-015-1775-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 11/12/2015] [Accepted: 11/14/2015] [Indexed: 11/25/2022]
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Scalabrino ML, Boye SL, Fransen KMH, Noel JM, Dyka FM, Min SH, Ruan Q, De Leeuw CN, Simpson EM, Gregg RG, McCall MA, Peachey NS, Boye SE. Intravitreal delivery of a novel AAV vector targets ON bipolar cells and restores visual function in a mouse model of complete congenital stationary night blindness. Hum Mol Genet 2015; 24:6229-39. [PMID: 26310623 DOI: 10.1093/hmg/ddv341] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/17/2015] [Indexed: 11/13/2022] Open
Abstract
Adeno-associated virus (AAV) effectively targets therapeutic genes to photoreceptors, pigment epithelia, Müller glia and ganglion cells of the retina. To date, no one has shown the ability to correct, with gene replacement, an inherent defect in bipolar cells (BCs), the excitatory interneurons of the retina. Targeting BCs with gene replacement has been difficult primarily due to the relative inaccessibility of BCs to standard AAV vectors. This approach would be useful for restoration of vision in patients with complete congenital stationary night blindness (CSNB1), where signaling through the ON BCs is eliminated due to mutations in their G-protein-coupled cascade genes. For example, the majority of CSNB1 patients carry a mutation in nyctalopin (NYX), which encodes a protein essential for proper localization of the TRPM1 cation channel required for ON BC light-evoked depolarization. As a group, CSNB1 patients have a normal electroretinogram (ERG) a-wave, indicative of photoreceptor function, but lack a b-wave due to defects in ON BC signaling. Despite retinal dysfunction, the retinas of CSNB1 patients do not degenerate. The Nyx(nob) mouse model of CSNB1 faithfully mimics this phenotype. Here, we show that intravitreally injected, rationally designed AAV2(quadY-F+T-V) containing a novel 'Ple155' promoter drives either GFP or YFP_Nyx in postnatal Nyx(nob) mice. In treated Nyx(nob) retina, robust and targeted Nyx transgene expression in ON BCs partially restored the ERG b-wave and, at the cellular level, signaling in ON BCs. Our results support the potential for gene delivery to BCs and gene replacement therapy in human CSNB1.
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Affiliation(s)
| | | | | | | | | | | | | | - Charles N De Leeuw
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V5Z 4H4, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V5Z 4H4, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Ronald G Gregg
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40202, USA
| | - Maureen A McCall
- Department of Ophthalmology and Visual Sciences, Department of Anatomical Sciences and Neurobiology and
| | - Neal S Peachey
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Shannon E Boye
- Department of Ophthalmology and, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL 32610, USA,
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Van Gelder RN, Kaur K. Vision Science: Can Rhodopsin Cure Blindness? Curr Biol 2015; 25:R713-5. [PMID: 26294183 DOI: 10.1016/j.cub.2015.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Outer retinal degeneration is the leading cause of blindness in the developed world. A new study now demonstrates that ectopic expression of human rhodopsin in the inner retina, mediated by viral gene therapy, can restore light sensitivity and some vision to mice blind from outer retinal degeneration.
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Affiliation(s)
- Russell N Van Gelder
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98104, USA; Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98104, USA; Department of Pathology, University of Washington School of Medicine, Seattle, WA 98104, USA.
| | - Kuldeep Kaur
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98104, USA
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Chakraborty R, Park HN, Hanif AM, Sidhu CS, Iuvone PM, Pardue MT. ON pathway mutations increase susceptibility to form-deprivation myopia. Exp Eye Res 2015; 137:79-83. [PMID: 26072023 PMCID: PMC4523446 DOI: 10.1016/j.exer.2015.06.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/24/2015] [Accepted: 06/09/2015] [Indexed: 01/15/2023]
Abstract
The ON pathway mutation in nob mice is associated with altered refractive development, and an increased susceptibility to form-deprivation (FD) myopia. In this study, we used mGluR6-/- mice, another ON pathway mutant, to determine whether the nob phenotype was due to the Nyx mutation or abnormal ON pathway transmission. Refractive development under a normal visual environment for mGluR6-/- and age-matched wild-type (WT) mice was measured every 2 weeks from 4 to 16 weeks of age. The response to monocular FD from 4 weeks of age was measured weekly in a separate cohort of mice. Refraction and ocular biometry were obtained using a photorefractor and optical coherence tomography. Retinas were harvested at 16 weeks, and analyzed for dopamine (DA) and DOPAC using high-performance liquid chromatography. Under normal conditions, mGluR6-/- mice were significantly more myopic than their WT controls (refraction at 12 weeks; WT: 9.40 ± 0.16 D, mGluR6-/-: 6.91 ± 0.38 D). Similar to nob mice, two weeks of FD resulted in a significant myopic shift of -5.57 ± 0.72 D in mGluR6-/- mice compared to -1.66 ± 0.19 D in WT animals. No significant axial length changes were observed with either normal or FD visual conditions. At 16 weeks, mGluR6-/- retinas showed significantly lower DOPAC levels (111.2 ± 33.0 pg/mg) compared to their WT counterparts (197.5 ± 11.2 pg/mg). Retinal DA levels were similar between the different genotypes. Our results indicate that reduced retinal DA metabolism/turnover may be associated with increased susceptibility to myopia in mice with ON pathway defect mutations.
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Affiliation(s)
- Ranjay Chakraborty
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA
| | - Han Na Park
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA
| | - Adam M Hanif
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA
| | - Curran S Sidhu
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA; Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Machelle T Pardue
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA.
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Schneider FM, Mohr F, Behrendt M, Oberwinkler J. Properties and functions of TRPM1 channels in the dendritic tips of retinal ON-bipolar cells. Eur J Cell Biol 2015; 94:420-7. [PMID: 26111660 DOI: 10.1016/j.ejcb.2015.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
An increase in light intensity induces a depolarization in retinal ON-bipolar cells via a reduced glutamate release from presynaptic photoreceptor cells. The underlying transduction cascade in the dendritic tips of ON-bipolar cells involves mGluR6 glutamate receptors signaling to TRPM1 proteins that are an indispensable part of the transduction channel. Several other proteins are recognized to participate in the transduction machinery. Deficiency in many of these leads to congenital stationary night blindness, because rod bipolar cells, a subgroup of ON-bipolar cells, constitute the main route for sensory information under scotopic conditions. Here, we review the current knowledge about TRPM1 ion channels and how their activity is regulated within the postsynaptic compartment of ON-bipolar cells. The functional properties of TRPM1 channels in the dendritic compartment are not well understood as they differ substantially from those of recombinant TRPM1 channels. Critical evaluation of possible explanations of these discrepancies indicates that some key components of this transduction pathway might still not be known. The continued exploration of this pathway will yield further clinically useful insights.
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Affiliation(s)
- Franziska M Schneider
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Florian Mohr
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Marc Behrendt
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany.
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Cronin T, Vandenberghe LH, Hantz P, Juttner J, Reimann A, Kacsó AE, Huckfeldt RM, Busskamp V, Kohler H, Lagali PS, Roska B, Bennett J. Efficient transduction and optogenetic stimulation of retinal bipolar cells by a synthetic adeno-associated virus capsid and promoter. EMBO Mol Med 2015; 6:1175-90. [PMID: 25092770 PMCID: PMC4197864 DOI: 10.15252/emmm.201404077] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this report, we describe the development of a modified adeno-associated virus (AAV) capsid and promoter for transduction of retinal ON-bipolar cells. The bipolar cells, which are post-synaptic to the photoreceptors, are important retinal targets for both basic and preclinical research. In particular, a therapeutic strategy under investigation for advanced forms of blindness involves using optogenetic molecules to render ON-bipolar cells light-sensitive. Currently, delivery of adequate levels of gene expression is a limiting step for this approach. The synthetic AAV capsid and promoter described here achieves high level of optogenetic transgene expression in ON-bipolar cells. This evokes high-frequency (∼100 Hz) spiking responses in ganglion cells of previously blind, rd1, mice. Our vector is a promising vehicle for further development toward potential clinical use.
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Affiliation(s)
- Therese Cronin
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Luk H Vandenberghe
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Péter Hantz
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Josephine Juttner
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Andreas Reimann
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | | | - Rachel M Huckfeldt
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Volker Busskamp
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland Genetics Department, Harvard Medical School, Boston, MA, USA
| | - Hubertus Kohler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Pamela S Lagali
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Botond Roska
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jean Bennett
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
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Nash BM, Wright DC, Grigg JR, Bennetts B, Jamieson RV. Retinal dystrophies, genomic applications in diagnosis and prospects for therapy. Transl Pediatr 2015; 4:139-63. [PMID: 26835369 PMCID: PMC4729094 DOI: 10.3978/j.issn.2224-4336.2015.04.03] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Retinal dystrophies (RDs) are degenerative diseases of the retina which have marked clinical and genetic heterogeneity. Common presentations among these disorders include night or colour blindness, tunnel vision and subsequent progression to complete blindness. The known causative disease genes have a variety of developmental and functional roles with mutations in more than 120 genes shown to be responsible for the phenotypes. In addition, mutations within the same gene have been shown to cause different disease phenotypes, even amongst affected individuals within the same family highlighting further levels of complexity. The known disease genes encode proteins involved in retinal cellular structures, phototransduction, the visual cycle, and photoreceptor structure or gene regulation. This review aims to demonstrate the high degree of genetic complexity in both the causative disease genes and their associated phenotypes, highlighting the more common clinical manifestation of retinitis pigmentosa (RP). The review also provides insight to recent advances in genomic molecular diagnosis and gene and cell-based therapies for the RDs.
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Affiliation(s)
- Benjamin M Nash
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Dale C Wright
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - John R Grigg
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Bruce Bennetts
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Robyn V Jamieson
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
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Omori Y, Kitamura T, Yoshida S, Kuwahara R, Chaya T, Irie S, Furukawa T. Mef2d is essential for the maturation and integrity of retinal photoreceptor and bipolar cells. Genes Cells 2015; 20:408-26. [PMID: 25757744 DOI: 10.1111/gtc.12233] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 01/30/2015] [Indexed: 11/29/2022]
Abstract
Mef2 transcription factors play a crucial role in cardiac and skeletal muscle differentiation. We found that Mef2d is highly expressed in the mouse retina and its loss causes photoreceptor degeneration similar to that observed in human retinitis pigmentosa patients. Electroretinograms (ERGs) were severely impaired in Mef2d-/- mice. Immunohistochemistry showed that photoreceptor and bipolar cell synapse protein levels severely decreased in the Mef2d-/- retina. Expression profiling by microarray analysis showed that Mef2d is required for the expression of various genes in photoreceptor and bipolar cells, including cone arrestin, Guca1b, Pde6h and Cacna1s, which encode outer segment and synapse proteins. We also observed that Mef2d synergistically activates the cone arrestin (Arr3) promoter with Crx, suggesting that functional cooperation between Mef2d and Crx is important for photoreceptor cell gene regulation. Taken together, our results show that Mef2d is essential for photoreceptor and bipolar cell gene expression, either independently or cooperatively with Crx.
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Affiliation(s)
- Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan; JST, CREST, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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46
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Congenital stationary night blindness: An analysis and update of genotype–phenotype correlations and pathogenic mechanisms. Prog Retin Eye Res 2015; 45:58-110. [DOI: 10.1016/j.preteyeres.2014.09.001] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/25/2014] [Accepted: 09/30/2014] [Indexed: 01/18/2023]
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Xiong WH, Brown RL, Reed B, Burke NS, Duvoisin RM, Morgans CW. Voriconazole, an antifungal triazol that causes visual side effects, is an inhibitor of TRPM1 and TRPM3 channels. Invest Ophthalmol Vis Sci 2015; 56:1367-73. [PMID: 25650413 DOI: 10.1167/iovs.14-15270] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Administration of voriconazole, an antifungal triazole, causes transient visual disturbances in patients and attenuates the b-wave of the ERG. We sought to identify the retinal target of voriconazole underlying the effect on the ERG b-wave. METHODS Electroretinograms were recorded from mice before and after intraperitoneal injection of voriconazole. The effect of voriconazole on ON-bipolar cells was tested by patch-clamp recordings of ON-bipolar cells in mouse retinal slices. Effects of voriconazole on mGluR6 and TRPM3 were assessed by patch-clamp recordings of Chinese hamster ovary (CHO) and HEK293 cells transfected with either TRPM3 or mGluR6 plus Kir3.1/Kir3.4. RESULTS Voriconazole attenuated the ERG b-wave in mice, and inhibited ON-bipolar cell responses evoked by application of CPPG, an mGluR6 antagonist, onto the ON-bipolar cell dendrites, indicating that voriconazole blocks a step in the mGluR6-TRPM1 signal transduction pathway. Voriconazole almost completely blocked capsaicin-activated currents in ON-bipolar cells, which have been attributed to direct activation of the TRPM1 cation channel. Furthermore, application of voriconazole to CHO cells expressing TRPM3, a closely related channel to TRPM1, showed that voriconazole reversibly blocked pregnenolone sulfate-stimulated TRPM3 currents in transfected cells. In contrast, voriconazole only slightly inhibited mGluR6-mediated activation of G-protein activated inward rectifier potassium (GIRK) currents in cotransfected cells, suggesting that mGluR6 is not the primary target of voriconazole in ON-bipolar cells. CONCLUSIONS The visual disturbances associated with voriconazole are likely due to block of TRPM1 channels in retinal ON-bipolar cells. Other neurological effects of voriconazole may be due to block of TRPM3 channels expressed in the brain.
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Affiliation(s)
- Wei-Hong Xiong
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States
| | - R Lane Brown
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, United States
| | - Brian Reed
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, United States
| | - Neal S Burke
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, United States
| | - Robert M Duvoisin
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States
| | - Catherine W Morgans
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States
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48
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Ramakrishnan H, Dhingra A, Tummala SR, Fina ME, Li JJ, Lyubarsky A, Vardi N. Differential function of Gγ13 in rod bipolar and ON cone bipolar cells. J Physiol 2015; 593:1531-50. [PMID: 25416620 DOI: 10.1113/jphysiol.2014.281196] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 11/12/2014] [Indexed: 01/17/2023] Open
Abstract
Heterotrimeric G-proteins (comprising Gα and Gβγ subunits) are critical for coupling of metabotropic receptors to their downstream effectors. In the retina, glutamate released from photoreceptors in the dark activates metabotropic glutamate receptor 6 (mGluR6) receptors in ON bipolar cells; this leads to activation of Go , closure of transient receptor potential melastatin 1 channels and hyperpolarization of these cells. Go comprises Gαo , Gβ3 and a Gγ. The best Gγ candidate is Gγ13, although functional data to support this are lacking. Thus, we tested Gγ13 function by generating Gng13(-/-) knockout (KO) mice, recording electroretinograms (ERG) and performing immunocytochemical staining. The amplitude of scotopic ERG b-waves in KO mice was lower than in wild-type (WT) mice. Furthermore, in both KO and WT mice, the ERG b-wave decreased with age; this decrease was much more pronounced in KO mice. By contrast, the photopic ERG b-waves in KO mice were hardly affected at any age. In KO mice retinas, immunostaining for Gβ3 and for the GTPase activating proteins RGS7, RGS11, R9AP and Gβ5 decreased significantly in rod bipolar cells but not in ON cone bipolar cells. Staining for Gαo and certain other cascade elements decreased only slightly. Analysis of our ON bipolar cDNA library showed that these cells express mRNAs for Gγ5, Gγ10 and Gγ11. Quantitative RT-PCR of retinal cDNA showed greater values for these transcripts in retinas of KO mice, although the difference was not significant. Our results suggest that Gγ13 contributes to mGluR6 signalling in rod bipolar cells more than in ON cone bipolar cells, and that this contribution includes both coupling the receptor and maintaining a stable localization of the mGluR6-related cascade elements.
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Affiliation(s)
- Hariharasubramanian Ramakrishnan
- Department of Neuroscience, Department of Neurology and Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Martemyanov KA. G protein signaling in the retina and beyond: the Cogan lecture. Invest Ophthalmol Vis Sci 2014; 55:8201-7. [PMID: 25511392 PMCID: PMC4541486 DOI: 10.1167/iovs.14-15928] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Kirill A. Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States
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50
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Popova E. ON-OFF Interactions in the Retina: Role of Glycine and GABA. Curr Neuropharmacol 2014; 12:509-26. [PMID: 25977678 PMCID: PMC4428025 DOI: 10.2174/1570159x13999150122165018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/19/2014] [Accepted: 12/22/2014] [Indexed: 01/03/2023] Open
Abstract
In the vertebrate retina, visual signals are segregated into parallel ON and OFF pathways, which provide information for light increments and decrements. The segregation is first evident at the level of the ON and OFF bipolar cells and it apparently remains as signals propagate to higher brain visual centers. A fundamental question in visual neuroscience is how these two parallel pathways function: are they independent from each other or do they interact somehow? In the latter case, what kinds of mechanisms are involved and what are the consequences from this cross-talk? This review summarizes current knowledge about the types of interactions between the ON and OFF channels in nonmammalian and mammalian retina. Data concerning the ON-OFF interactions in distal retina revealed by recording of single bipolar cell activity and electroretinographic ON (b-wave) and OFF (d-wave) responses are presented. Special emphasis is put on the ON-OFF interactions in proximal retina and their dependence on the state of light adaptation in mammalian retina. The involvement of the GABAergic and glycinergic systems in the ON-OFF crosstalk is also discussed.
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Affiliation(s)
- Elka Popova
- Department of Physiology, Medical Phaculty, Medical University, 1431 Sofia, Country Bulgaria
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