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Monson E, Cideciyan AV, Roman AJ, Sumaroka A, Swider M, Wu V, Viarbitskaya I, Jacobson SG, Fliesler SJ, Pittler SJ. Inherited Retinal Degeneration Caused by Dehydrodolichyl Diphosphate Synthase Mutation-Effect of an ALG6 Modifier Variant. Int J Mol Sci 2024; 25:1004. [PMID: 38256083 PMCID: PMC10816542 DOI: 10.3390/ijms25021004] [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: 12/11/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Modern advances in disease genetics have uncovered numerous modifier genes that play a role in the severity of disease expression. One such class of genetic conditions is known as inherited retinal degenerations (IRDs), a collection of retinal degenerative disorders caused by mutations in over 300 genes. A single missense mutation (K42E) in the gene encoding the enzyme dehydrodolichyl diphosphate synthase (DHDDS), which is required for protein N-glycosylation in all cells and tissues, causes DHDDS-IRD (retinitis pigmentosa type 59 (RP59; OMIM #613861)). Apart from a retinal phenotype, however, DHDDS-IRD is surprisingly non-syndromic (i.e., without any systemic manifestations). To explore disease pathology, we selected five glycosylation-related genes for analysis that are suggested to have disease modifier variants. These genes encode glycosyltransferases (ALG6, ALG8), an ER resident protein (DDOST), a high-mannose oligosaccharyl transferase (MPDU1), and a protein N-glycosylation regulatory protein (TNKS). DNA samples from 11 confirmed DHDDS (K42E)-IRD patients were sequenced at the site of each candidate genetic modifier. Quantitative measures of retinal structure and function were performed across five decades of life by evaluating foveal photoreceptor thickness, visual acuity, foveal sensitivity, macular and extramacular rod sensitivity, and kinetic visual field extent. The ALG6 variant, (F304S), was correlated with greater macular cone disease severity and less peripheral rod disease severity. Thus, modifier gene polymorphisms may account for a significant portion of phenotypic variation observed in human genetic disease. However, the consequences of the polymorphisms may be counterintuitively complex in terms of rod and cone populations affected in different regions of the retina.
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Affiliation(s)
- Elisha Monson
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Artur V. Cideciyan
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Alejandro J. Roman
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Alexander Sumaroka
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Malgorzata Swider
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Vivian Wu
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Iryna Viarbitskaya
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Samuel G. Jacobson
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (A.J.R.); (A.S.); (M.S.); (V.W.); (I.V.)
| | - Steven J. Fliesler
- Departments of Ophthalmology and Biochemistry, and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York—University at Buffalo, Buffalo, NY 14203, USA;
- Research Service, VA Western NY Healthcare System, Buffalo, NY 14215, USA
| | - Steven J. Pittler
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
- Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Lee HS, Jang S, Eom Y, Kim KT. Comparing Ocular Toxicity of Legacy and Alternative Per- and Polyfluoroalkyl Substances in Zebrafish Larvae. TOXICS 2023; 11:1021. [PMID: 38133422 PMCID: PMC10747198 DOI: 10.3390/toxics11121021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
Studies comparing the ocular toxicity potential between legacy and alternative PFAS are lacking. To address this research gap, zebrafish larvae were exposed to both legacy PFAS (i.e., perfluorooctanesulfonic acid [PFOS] and perfluorooctanoic acid [PFOA]) and their corresponding alternatives (i.e., perfluorobutanesulfonic acid [PFBS] and perfluorobutanoic acid [PFBA]). Alterations in their visual behaviors, such as phototactic and optomotor responses (OMR), were assessed at sublethal concentrations. Gene expression variations in visual function-associated pathways were also measured. Visual behavioral assessment revealed that PFOS exposure resulted in concentration-dependent reductions in phototactic responses at 10-1000 μg/L, with PFOA exerting reduction effects only at 100 mg/L. However, their two alternatives had no effect at all tested concentrations. Following an improved contrast-OMR (C-OMR) assessment, PFOS decreased the OMR to a water flow stimulus at 10, 100, and 1000 μg/L. The gene expression analysis revealed that PFOS exposure markedly downregulated most genes involved in the opsins in the photoreceptor and phototransduction cascade, which explains the observed visual behavior changes well. Our findings indicate that PFOS is the most likely PFAS to cause visual toxicity, with PFOA present but less likely, and their substitutes, PFBS and PFBA, cannot be classified as visually toxic to zebrafish.
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Affiliation(s)
- Han-seul Lee
- Department of Environmental Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
| | - Soogyeong Jang
- Department of Environmental Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
| | - Youngsub Eom
- Zebrafish Translational Medical Research Center, Korea University, Ansan 15355, Republic of Korea
- Department of Ophthalmology, Korea University Ansan Hospital, Ansan 15355, Republic of Korea
- Department of Ophthalmology, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Ki-Tae Kim
- Department of Environmental Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
- Department of Environmental Energy Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
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Kovács-Valasek A, Rák T, Pöstyéni E, Csutak A, Gábriel R. Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them. Int J Mol Sci 2023; 24:ijms24108728. [PMID: 37240082 DOI: 10.3390/ijms24108728] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases-the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.
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Affiliation(s)
- Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
| | - Tibor Rák
- Department of Ophthalmology, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
| | - Adrienne Csutak
- Department of Ophthalmology, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Robert Gábriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
- János Szentágothai Research Centre, University of Pécs, Ifjúság útja 20, 7624 Pécs, Hungary
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Yamoah A, Tripathi P, Guo H, Scheve L, Walter P, Johnen S, Müller F, Weis J, Goswami A. Early Alterations of RNA Binding Protein (RBP) Homeostasis and ER Stress-Mediated Autophagy Contributes to Progressive Retinal Degeneration in the rd10 Mouse Model of Retinitis Pigmentosa (RP). Cells 2023; 12:cells12071094. [PMID: 37048167 PMCID: PMC10092976 DOI: 10.3390/cells12071094] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 04/14/2023] Open
Abstract
The retinal degeneration 10 (rd10) mouse model is widely used to study retinitis pigmentosa (RP) pathomechanisms. It offers a rather unique opportunity to study trans-neuronal degeneration because the cell populations in question are separated anatomically and the mutated Pde6b gene is selectively expressed in rod photoreceptors. We hypothesized that RNA binding protein (RBP) aggregation and abnormal autophagy might serve as early pathogenic events, damaging non-photoreceptor retinal cell types that are not primarily targeted by the Pde6b gene defect. We used a combination of immunohistochemistry (DAB, immunofluorescence), electron microscopy (EM), subcellular fractionation, and Western blot analysis on the retinal preparations obtained from both rd10 and wild-type mice. We found early, robust increases in levels of the protective endoplasmic reticulum (ER) calcium (Ca2+) buffering chaperone Sigma receptor 1 (SigR1) together with other ER-Ca2+ buffering proteins in both photoreceptors and non-photoreceptor neuronal cells before any noticeable photoreceptor degeneration. In line with this, we found markedly altered expression of the autophagy proteins p62 and LC3, together with abnormal ER widening and large autophagic vacuoles as detected by EM. Interestingly, these changes were accompanied by early, prominent cytoplasmic and nuclear aggregation of the key RBPs including pTDP-43 and FET family RBPs and stress granule formation. We conclude that progressive neurodegeneration in the rd10 mouse retina is associated with early disturbances of proteostasis and autophagy, along with abnormal cytoplasmic RBP aggregation.
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Affiliation(s)
- Alfred Yamoah
- Institute of Neuropathology, University Hospital RWTH Aachen, 52074 Aachen, Germany
- EURON-European Graduate School of Neuroscience, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Priyanka Tripathi
- Institute of Neuropathology, University Hospital RWTH Aachen, 52074 Aachen, Germany
- EURON-European Graduate School of Neuroscience, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Haihong Guo
- Institute of Neuropathology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Leonie Scheve
- Institute of Neuropathology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Peter Walter
- Department of Ophthalmology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Sandra Johnen
- Department of Ophthalmology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Frank Müller
- Institute of Biological Information Processing, Molecular and Cellular Physiology, IBI-1, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Joachim Weis
- Institute of Neuropathology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Anand Goswami
- Institute of Neuropathology, University Hospital RWTH Aachen, 52074 Aachen, Germany
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Eleanor and Lou Gehrig ALS Center, Columbia University, New York, NY 10032, USA
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Kuzelova A, Dupacova N, Antosova B, Sunny SS, Kozmik Z, Paces J, Skoultchi AI, Stopka T, Kozmik Z. Chromatin Remodeling Enzyme Snf2h Is Essential for Retinal Cell Proliferation and Photoreceptor Maintenance. Cells 2023; 12:1035. [PMID: 37048108 PMCID: PMC10093269 DOI: 10.3390/cells12071035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023] Open
Abstract
Chromatin remodeling complexes are required for many distinct nuclear processes such as transcription, DNA replication, and DNA repair. However, the contribution of these complexes to the development of complex tissues within an organism is poorly characterized. Imitation switch (ISWI) proteins are among the most evolutionarily conserved ATP-dependent chromatin remodeling factors and are represented by yeast Isw1/Isw2, and their vertebrate counterparts Snf2h (Smarca5) and Snf2l (Smarca1). In this study, we focused on the role of the Snf2h gene during the development of the mammalian retina. We show that Snf2h is expressed in both retinal progenitors and post-mitotic retinal cells. Using Snf2h conditional knockout mice (Snf2h cKO), we found that when Snf2h is deleted, the laminar structure of the adult retina is not retained, the overall thickness of the retina is significantly reduced compared with controls, and the outer nuclear layer (ONL) is completely missing. The depletion of Snf2h did not influence the ability of retinal progenitors to generate all the differentiated retinal cell types. Instead, the Snf2h function is critical for the proliferation of retinal progenitor cells. Cells lacking Snf2h have a defective S-phase, leading to the entire cell division process impairments. Although all retinal cell types appear to be specified in the absence of the Snf2h function, cell-cycle defects and concomitantly increased apoptosis in Snf2h cKO result in abnormal retina lamination, complete destruction of the photoreceptor layer, and consequently, a physiologically non-functional retina.
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Affiliation(s)
- Andrea Kuzelova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Naoko Dupacova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Barbora Antosova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Sweetu Susan Sunny
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Jan Paces
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Arthur I. Skoultchi
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA
| | - Tomas Stopka
- Biocev, First Faculty of Medicine, Charles University, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, Czech Republic
- Research Unit for Rare Diseases, Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
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6
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Kuzelova A, Dupacova N, Antosova B, Sunny SS, Kozmik Z, Paces J, Skoultchi AI, Stopka T, Kozmik Z. Chromatin remodeling enzyme Snf2h is essential for retinal cell proliferation and photoreceptor maintenance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.13.528323. [PMID: 36824843 PMCID: PMC9948993 DOI: 10.1101/2023.02.13.528323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Chromatin remodeling complexes are required for many distinct nuclear processes such as transcription, DNA replication and DNA repair. However, how these complexes contribute to the development of complex tissues within an organism is poorly characterized. Imitation switch (ISWI) proteins are among the most evolutionarily conserved ATP-dependent chromatin remodeling factors and are represented by yeast Isw1/Isw2, and their vertebrate counterparts Snf2h (Smarca5) and Snf2l (Smarca1). In this study, we focused on the role of the Snf2h gene during development of the mammalian retina. We show that Snf2h is expressed in both retinal progenitors and post-mitotic retinal cells. Using Snf2h conditional knockout mice ( Snf2h cKO), we found that when Snf2h is deleted the laminar structure of the adult retina is not retained, the overall thickness of the retina is significantly reduced compared with controls, and the outer nuclear layer (ONL) is completely missing. Depletion of Snf2h did not influence the ability of retinal progenitors to generate all of the differentiated retinal cell types. Instead, Snf2h function is critical for proliferation of retinal progenitor cells. Cells lacking Snf2h have a defective S-phase, leading to the entire cell division process impairments. Although, all retinal cell types appear to be specified in the absence of Snf2h function, cell cycle defects and concomitantly increased apoptosis in Snf2h cKO result in abnormal retina lamination, complete destruction of the photoreceptor layer and, consequently, in a physiologically non-functional retina.
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Karamali F, Behtaj S, Babaei-Abraki S, Hadady H, Atefi A, Savoj S, Soroushzadeh S, Najafian S, Nasr Esfahani MH, Klassen H. Potential therapeutic strategies for photoreceptor degeneration: the path to restore vision. J Transl Med 2022; 20:572. [PMID: 36476500 PMCID: PMC9727916 DOI: 10.1186/s12967-022-03738-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/29/2022] [Indexed: 12/12/2022] Open
Abstract
Photoreceptors (PRs), as the most abundant and light-sensing cells of the neuroretina, are responsible for converting light into electrical signals that can be interpreted by the brain. PR degeneration, including morphological and functional impairment of these cells, causes significant diminution of the retina's ability to detect light, with consequent loss of vision. Recent findings in ocular regenerative medicine have opened promising avenues to apply neuroprotective therapy, gene therapy, cell replacement therapy, and visual prostheses to the challenge of restoring vision. However, successful visual restoration in the clinical setting requires application of these therapeutic approaches at the appropriate stage of the retinal degeneration. In this review, firstly, we discuss the mechanisms of PR degeneration by focusing on the molecular mechanisms underlying cell death. Subsequently, innovations, recent developments, and promising treatments based on the stage of disorder progression are further explored. Then, the challenges to be addressed before implementation of these therapies in clinical practice are considered. Finally, potential solutions to overcome the current limitations of this growing research area are suggested. Overall, the majority of current treatment modalities are still at an early stage of development and require extensive additional studies, both pre-clinical and clinical, before full restoration of visual function in PR degeneration diseases can be realized.
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Affiliation(s)
- Fereshteh Karamali
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sanaz Behtaj
- grid.1022.10000 0004 0437 5432Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Queensland, Australia ,grid.1022.10000 0004 0437 5432Menzies Health Institute Queensland, Griffith University, Southport, QLD 4222 Australia
| | - Shahnaz Babaei-Abraki
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Hanieh Hadady
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Atefeh Atefi
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Soraya Savoj
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sareh Soroushzadeh
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Samaneh Najafian
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Hossein Nasr Esfahani
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Henry Klassen
- grid.266093.80000 0001 0668 7243Gavin Herbert Eye Institute, Irvine, CA USA
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Lohia A, Sahel DK, Salman M, Singh V, Mariappan I, Mittal A, Chitkara D. Delivery Strategies for CRISPR/Cas Genome editing tool for Retinal Dystrophies: challenges and opportunities. Asian J Pharm Sci 2022; 17:153-176. [PMID: 36320315 PMCID: PMC9614410 DOI: 10.1016/j.ajps.2022.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/01/2021] [Accepted: 02/04/2022] [Indexed: 12/12/2022] Open
Abstract
CRISPR/Cas, an adaptive immune system in bacteria, has been adopted as an efficient and precise tool for site-specific gene editing with potential therapeutic opportunities. It has been explored for a variety of applications, including gene modulation, epigenome editing, diagnosis, mRNA editing, etc. It has found applications in retinal dystrophic conditions including progressive cone and cone-rod dystrophies, congenital stationary night blindness, X-linked juvenile retinoschisis, retinitis pigmentosa, age-related macular degeneration, leber's congenital amaurosis, etc. Most of the therapies for retinal dystrophic conditions work by regressing symptoms instead of reversing the gene mutations. CRISPR/Cas9 through indel could impart beneficial effects in the reversal of gene mutations in dystrophic conditions. Recent research has also consolidated on the approaches of using CRISPR systems for retinal dystrophies but their delivery to the posterior part of the eye is a major concern due to high molecular weight, negative charge, and in vivo stability of CRISPR components. Recently, non-viral vectors have gained interest due to their potential in tissue-specific nucleic acid (miRNA/siRNA/CRISPR) delivery. This review highlights the opportunities of retinal dystrophies management using CRISPR/Cas nanomedicine.
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Jaroszynska N, Harding P, Moosajee M. Metabolism in the Zebrafish Retina. J Dev Biol 2021; 9:10. [PMID: 33804189 PMCID: PMC8006245 DOI: 10.3390/jdb9010010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
Retinal photoreceptors are amongst the most metabolically active cells in the body, consuming more glucose as a metabolic substrate than even the brain. This ensures that there is sufficient energy to establish and maintain photoreceptor functions during and after their differentiation. Such high dependence on glucose metabolism is conserved across vertebrates, including zebrafish from early larval through to adult retinal stages. As the zebrafish retina develops rapidly, reaching an adult-like structure by 72 hours post fertilisation, zebrafish larvae can be used to study metabolism not only during retinogenesis, but also in functionally mature retinae. The interplay between rod and cone photoreceptors and the neighbouring retinal pigment epithelium (RPE) cells establishes a metabolic ecosystem that provides essential control of their individual functions, overall maintaining healthy vision. The RPE facilitates efficient supply of glucose from the choroidal vasculature to the photoreceptors, which produce metabolic products that in turn fuel RPE metabolism. Many inherited retinal diseases (IRDs) result in photoreceptor degeneration, either directly arising from photoreceptor-specific mutations or secondary to RPE loss, leading to sight loss. Evidence from a number of vertebrate studies suggests that the imbalance of the metabolic ecosystem in the outer retina contributes to metabolic failure and disease pathogenesis. The use of larval zebrafish mutants with disease-specific mutations that mirror those seen in human patients allows us to uncover mechanisms of such dysregulation and disease pathology with progression from embryonic to adult stages, as well as providing a means of testing novel therapeutic approaches.
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Affiliation(s)
| | - Philippa Harding
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK;
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK;
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- The Francis Crick Institute, London NW1 1AT, UK
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Kim TH, Wang B, Lu Y, Son T, Yao X. Functional optical coherence tomography enables in vivo optoretinography of photoreceptor dysfunction due to retinal degeneration. BIOMEDICAL OPTICS EXPRESS 2020; 11:5306-5320. [PMID: 33014616 PMCID: PMC7510876 DOI: 10.1364/boe.399334] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/20/2020] [Accepted: 08/20/2020] [Indexed: 05/16/2023]
Abstract
Stimulus-evoked intrinsic optical signal (IOS), which occurs almost immediately after the onset of retinal stimulus has been observed in retinal photoreceptors, promises to be a unique biomarker for objective optoretinography (ORG) of photoreceptor function. We report here the first-time in vivo ORG detection of photoreceptor dysfunction due to retinal degeneration. A custom-designed optical coherence tomography (OCT) was employed for longitudinal ORG monitoring of photoreceptor-IOS distortions in retinal degeneration mice. Depth-resolved OCT analysis confirmed the outer segment (OS) as the physical source of the photoreceptor-IOS. Comparative ERG measurement verified the phototransduction activation as the physiological correlator of the photoreceptor-IOS. Histological examination revealed disorganized OS discs, i.e. the pathological origin of the photoreceptor-IOS distortion.
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Affiliation(s)
- Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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Shrestha R, Wen YT, Tsai RK. Induced pluripotent stem cells and derivative photoreceptor precursors as therapeutic cells for retinal degenerations. Tzu Chi Med J 2020; 32:101-112. [PMID: 32269941 PMCID: PMC7137374 DOI: 10.4103/tcmj.tcmj_147_19] [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: 07/09/2019] [Revised: 07/28/2019] [Accepted: 08/06/2019] [Indexed: 12/25/2022] Open
Abstract
The visual impairment associated with inherited retinal degeneration and age-related degeneration of photoreceptors is causing substantial challenges in finding effective therapies. However, induced pluripotent stem cell (iPSC)-derived therapeutic cells such as photoreceptor and retinal pigment epithelium (RPE) cells provide the ultimate options in the rescue of lost photoreceptors to improve the visual function in end-stage degeneration. Retinal cells derived from iPSC are therapeutic cells that could be promising in the field of cell replacement therapy and regenerative medicine. This review presents an overview of the photoreceptor degeneration, methods of iPSC generation, iPSC in retinal disease modeling, summarizes the photoreceptor differentiation protocols, and challenges remained with photoreceptor cell replacement for the treatment of retinal diseases. Thus, the burden and increased incidence of visual impairment emphasizes the need of novel therapy, where iPSC-derived photoreceptor and RPE cells proved to be promising for curing the retinal dysfunction and act as renovation in approach to improve visual function.
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Affiliation(s)
- Rupendra Shrestha
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.,Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Yao-Tseng Wen
- Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Rong-Kung Tsai
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.,Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
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12
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Cisneros E, di Marco F, Rueda-Carrasco J, Lillo C, Pereyra G, Martín-Bermejo MJ, Vargas A, Sanchez R, Sandonís Á, Esteve P, Bovolenta P. Sfrp1 deficiency makes retinal photoreceptors prone to degeneration. Sci Rep 2020; 10:5115. [PMID: 32198470 PMCID: PMC7083943 DOI: 10.1038/s41598-020-61970-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/05/2020] [Indexed: 12/11/2022] Open
Abstract
Millions of individuals worldwide suffer from impaired vision, a condition with multiple origins that often impinge upon the light sensing cells of the retina, the photoreceptors, affecting their integrity. The molecular components contributing to this integrity are however not yet fully understood. Here we have asked whether Secreted Frizzled Related Protein 1 (SFRP1) may be one of such factors. SFRP1 has a context-dependent function as modulator of Wnt signalling or of the proteolytic activity of A Disintegrin And Metalloproteases (ADAM) 10, a main regulator of neural cell-cell communication. We report that in Sfrp1−/− mice, the outer limiting membrane (OLM) is discontinuous and the photoreceptors disorganized and more prone to light-induced damage. Sfrp1 loss significantly enhances the effect of the Rpe65Leu450Leu genetic variant -present in the mouse genetic background- which confers sensitivity to light-induced stress. These alterations worsen with age, affect visual function and are associated to an increased proteolysis of Protocadherin 21 (PCDH21), localized at the photoreceptor outer segment, and N-cadherin, an OLM component. We thus propose that SFRP1 contributes to photoreceptor fitness with a mechanism that involves the maintenance of OLM integrity. These conclusions are discussed in view of the broader implication of SFRP1 in neurodegeneration and aging.
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Affiliation(s)
- Elsa Cisneros
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain.,Departamento de Biología Celular y Patología, Universidad de Salamanca, Instituto de Neurociencias de Castilla y León and IBSAL, Salamanca, Spain.,Centro Universitario Internacional de Madrid (CUNIMAD), Dept. de Biología de Sistemas, Universidad de Alcalá, Madrid, Spain
| | - Fabiana di Marco
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | | | - Concepción Lillo
- Departamento de Biología Celular y Patología, Universidad de Salamanca, Instituto de Neurociencias de Castilla y León and IBSAL, Salamanca, Spain
| | | | | | - Alba Vargas
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Rocío Sanchez
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - África Sandonís
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Pilar Esteve
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Paola Bovolenta
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain.
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13
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Sex-related differences in the progressive retinal degeneration of the rd10 mouse. Exp Eye Res 2019; 187:107773. [PMID: 31445902 DOI: 10.1016/j.exer.2019.107773] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/21/2019] [Accepted: 08/21/2019] [Indexed: 01/30/2023]
Abstract
The retinal degeneration 10 (rd10) mouse is a model of autosomal recessive retinitis pigmentosa (RP), a disease that causes blindness through the progressive loss of photoreceptors. This study shows evidence of sex-related differences in RP onset and progression in rd10 retinas. The disease onset was considerably earlier in the female rd10 mice than in the male rd10 mice, as evidenced by a loss of PDE6β proteins and rod-dominated electroretinogram (ERG) responses at an early age. Single photopic flash and flicker ERG responses and immunolabeling of opsin molecules were analyzed in both genders to assess the sex differences in the degeneration of cones in the RP retinas. The averaged amplitudes of cone-mediated ERG responses obtained from the females were significantly smaller than the amplitudes of the responses from the age-matched males in the late stages of the RP, suggesting that cones might degenerate faster in the female retinas as the disease progressed. The rapid degeneration of cones caused a more substantial decrease in the ERG responses derived from the On-pathway than the Off-pathway in the females. In addition, the male rd10 mice had heavier body weights than their female counterparts aged between postnatal (P)18 and P50 days. In summary, female rd10 mice were more susceptible to retinal degeneration, suggesting that the female sex might be a risk factor for RP. The results have important implications for future studies exploring potential sex-related differences in RP development and progression in the clinic.
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Miragliotta V, Buonamici S, Coli A, Abramo F. Aging-associated perifollicular changes and calcium deposition in poodles. Vet Dermatol 2018; 30:56-e15. [PMID: 30461084 DOI: 10.1111/vde.12700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND It is commonly accepted that canine dystrophic mineralization of the hair follicle glassy membrane can be seen in hyperadrenocorticism and as a senile change in poodles. Pathology textbooks define this change as deposition of calcium salts in the form of basophilic, amorphous, granular material along collagen fibrils. HYPOTHESIS/OBJECTIVES The aim was to evaluate whether the incidence of the lesion is specific to poodles and if it is always associated with calcium deposition. ANIMALS One hundred and forty-seven dogs divided into three groups: (i) 91 normal poodles; (ii) 40 dogs of other breeds; and (iii) 16 dogs with clinical/histopathological diagnosis of hyperadrenocorticism. METHODS AND MATERIALS Retrospective study; with haematoxylin and eosin, and von Kossa staining. RESULTS Our findings demonstrate that perifollicular changes of the hair follicle glassy membrane of poodles are not always associated with calcium deposition. CONCLUSIONS AND CLINICAL IMPORTANCE A specific staining is needed to identify true calcium deposition when performing histological examination of the skin of poodles.
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Affiliation(s)
- Vincenzo Miragliotta
- Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56124, Pisa, Italy
| | - Sharon Buonamici
- Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56124, Pisa, Italy
| | - Alessandra Coli
- Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56124, Pisa, Italy
| | - Francesca Abramo
- Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56124, Pisa, Italy
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15
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Fu J, Nagashima M, Guo C, Raymond PA, Wei X. Novel Animal Model of Crumbs-Dependent Progressive Retinal Degeneration That Targets Specific Cone Subtypes. Invest Ophthalmol Vis Sci 2018; 59:505-518. [PMID: 29368007 PMCID: PMC5786287 DOI: 10.1167/iovs.17-22572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/10/2017] [Indexed: 01/01/2023] Open
Abstract
Purpose Human Crb1 is implicated in some forms of retinal degeneration, suggesting a role in photoreceptor maintenance. Multiple Crumbs (Crb) polarity genes are expressed in vertebrate retina, although their functional roles are not well understood. To gain further insight into Crb and photoreceptor maintenance, we compared retinal cell densities between wild-type and Tg(RH2-2:Crb2b-sfEX/RH2-2:GFP)pt108b transgenic zebrafish, in which the extracellular domain of Crb2b-short form (Crb2b-sfEX) is expressed in the retina as a secreted protein, which disrupts the planar organization of RGB cones (red, green, and blue) by interfering with Crb2a/2b-based cone-cone adhesion. Methods We used standard morphometric techniques to assess age-related changes in retinal cell densities in adult zebrafish (3 to 27 months old), and to assess effects of the Crb2b-sfEX transgene on retinal structure and photoreceptor densities. Linear cell densities were measured in all retinal layers in radial sections with JB4-Feulgen histology. Planar (surface) densities of cones were determined in retinal flat-mounts. Cell counts from wild-type and pt108b transgenic fish were compared with both a "photoreceptor maintenance index" and statistical analysis of cell counts. Results Age-related changes in retinal cell linear densities and cone photoreceptor planar densities in wild-type adult zebrafish provided a baseline for analysis. Expression of Crb2b-sfEX caused progressive and selective degeneration of RGB cones, but had no effect on ultraviolet-sensitive (UV) cones, and increased numbers of rod photoreceptors. Conclusions These differential responses of RGB cones, UV cones, and rods to sustained exposure to Crb2b-sfEX suggest that Crb-based photoreceptor maintenance mechanisms are highly selective.
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Affiliation(s)
- Jinling Fu
- Department of Ophthalmology, the Second Hospital of Jilin University, Changchun, Jilin, China
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Mikiko Nagashima
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States
| | - Chuanyu Guo
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Pamela A. Raymond
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States
| | - Xiangyun Wei
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Department of Developmental Biology, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, United States
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, United States
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, United States
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16
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Affiliation(s)
- Peter J Francis
- Eye Department, St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK.
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17
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Ito D, Kumanogoh A. The role of Sema4A in angiogenesis, immune responses, carcinogenesis, and retinal systems. Cell Adh Migr 2016; 10:692-699. [PMID: 27736304 PMCID: PMC5160039 DOI: 10.1080/19336918.2016.1215785] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Semaphorins were originally identified as axon guidance cues that regulate the functional activity of axons in the nervous system. In addition, accumulating evidence indicates that semaphorins have multiple functions in physiological and pathogenic processes, including vascular development, tumor progression, and immune responses. Sema4A is a semaphorin expressed in immune cells, and is thus termed an “immune semaphorin.” Sema4A has 4 types of receptors: Plexin D family, Plexin B family, Tim-2, and Nrp-1. Recent studies suggest that Sema4A plays critical roles in many processes including cell–cell interactions, immune-cell activation, differentiation, and migration. In other studies, Sema4A is also associated with carcinogenesis and retinal systems. In this review, we summarize current knowledge regarding the biology of Sema4A in relation to angiogenesis, immune responses, colorectal cancer, and the retina.
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Affiliation(s)
- Daisuke Ito
- a Department of Respiratory Medicine , Allergy and Rheumatic Disease, Osaka University Graduate School of Medicine , Suita , Osaka , Japan
| | - Atsushi Kumanogoh
- a Department of Respiratory Medicine , Allergy and Rheumatic Disease, Osaka University Graduate School of Medicine , Suita , Osaka , Japan
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De Novo Assembly and Transcriptome Characterization of Canine Retina Using High-Throughput Sequencing. GENETICS RESEARCH INTERNATIONAL 2015; 2015:638679. [PMID: 26788372 PMCID: PMC4695645 DOI: 10.1155/2015/638679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/10/2015] [Accepted: 11/11/2015] [Indexed: 01/29/2023]
Abstract
We performed transcriptome sequencing of canine retinal tissue by 454 GS-FLX and Ion Torrent PGM platforms. RNA-Seq analysis by CLC Genomics Workbench mapped expression of 10,360 genes. Gene ontology analysis of retinal transcriptome revealed abundance of transcripts known to be involved in vision associated processes. The de novo assembly of the sequences using CAP3 generated 29,683 contigs with mean length of 560.9 and N50 of 619 bases. Further analysis of contigs predicted 3,827 full-length cDNAs and 29,481 (99%) open reading frames (ORFs). In addition, 3,782 contigs were assigned to 316 KEGG pathways which included melanogenesis, phototransduction, and retinol metabolism with 33, 15, and 11 contigs, respectively. Among the identified microsatellites, dinucleotide repeats were 68.84%, followed by trinucleotides, tetranucleotides, pentanucleotides, and hexanucleotides in proportions of 25.76, 9.40, 2.52, and 0.96%, respectively. This study will serve as a valuable resource for understanding the biology and function of canine retina.
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The Role of the Endothelin System in the Vascular Dysregulation Involved in Retinitis Pigmentosa. J Ophthalmol 2015; 2015:405234. [PMID: 26613048 PMCID: PMC4647052 DOI: 10.1155/2015/405234] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 10/18/2015] [Indexed: 12/31/2022] Open
Abstract
Retinitis pigmentosa is a clinical and genetic group of inherited retinal disorders characterized by alterations of photoreceptors and retinal pigment epithelium leading to a progressive concentric visual field restriction, which may bring about severe central vision impairment. Haemodynamic studies in patients with retinitis pigmentosa have demonstrated ocular blood flow abnormalities both in retina-choroidal and in retroocular vascular system. Moreover, several investigations have studied the augmentation of endothelin-1 plasma levels systemically in the body and locally in the eye. This might account for vasoconstriction and ischemia, typical in vascular dysregulation syndrome, which can be considered an important factor of reduction of the ocular blood flow in subjects affected by retinitis pigmentosa.
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20
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Zhou S, Flamier A, Abdouh M, Tétreault N, Barabino A, Wadhwa S, Bernier G. Differentiation of human embryonic stem cells into cone photoreceptors through simultaneous inhibition of BMP, TGFβ and Wnt signaling. Development 2015; 142:3294-306. [DOI: 10.1242/dev.125385] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cone photoreceptors are required for color discrimination and high-resolution central vision and are lost in macular degenerations, cone and cone/rod dystrophies. Cone transplantation could represent a therapeutic solution. However, an abundant source of human cones remains difficult to obtain. Work performed in model organisms suggests that anterior neural cell fate is induced ‘by default' if BMP, TGFβ and Wnt activities are blocked, and that photoreceptor genesis operates through an S-cone default pathway. We report here that Coco (Dand5), a member of the Cerberus gene family, is expressed in the developing and adult mouse retina. Upon exposure to recombinant COCO, human embryonic stem cells (hESCs) differentiated into S-cone photoreceptors, developed an inner segment-like protrusion, and could degrade cGMP when exposed to light. Addition of thyroid hormone resulted in a transition from a unique S-cone population toward a mixed M/S-cone population. When cultured at confluence for a prolonged period of time, COCO-exposed hESCs spontaneously developed into a cellular sheet composed of polarized cone photoreceptors. COCO showed dose-dependent and synergistic activity with IGF1 at blocking BMP/TGFβ/Wnt signaling, while its cone-inducing activity was blocked in a dose-dependent manner by exposure to BMP, TGFβ or Wnt-related proteins. Our work thus provides a unique platform to produce human cones for developmental, biochemical and therapeutic studies and supports the hypothesis that photoreceptor differentiation operates through an S-cone default pathway during human retinal development.
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Affiliation(s)
- Shufeng Zhou
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Anthony Flamier
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Mohamed Abdouh
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Nicolas Tétreault
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Andrea Barabino
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Shashi Wadhwa
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Gilbert Bernier
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
- Department of Neuroscience, University of Montréal, Montréal H3T 1J4, Canada
- Department of Ophthalmology, University of Montréal, Montréal H3T 1J4, Canada
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STAT3 promotes survival of mutant photoreceptors in inherited photoreceptor degeneration models. Proc Natl Acad Sci U S A 2014; 111:E5716-23. [PMID: 25512545 DOI: 10.1073/pnas.1411248112] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Inherited photoreceptor degenerations (IPDs), a group of incurable progressive blinding diseases, are caused by mutations in more than 200 genes, but little is known about the molecular pathogenesis of photoreceptor (PR) death. Increased retinal expression of STAT3 has been observed in response to many retinal insults, including IPDs, but the role of this increase in PR death is unknown. Here, we show that the expression of Stat3 is increased in PRs of the Tg(RHO P347S) and Prph2(rds) (/+) mouse models of IPD and is activated by tyrosine phosphorylation. PR-specific deletion of Stat3 substantially accelerated PR degeneration in both mutant strains. In contrast, increased PR-specific expression of ROSA26 (R26) alleles encoding either WT STAT3 (Stat3(wt)) or the gain-of-function variant STAT3(C) (Stat3(C)) improved PR survival in both models. Moreover, PR signaling in Tg(RHO P347S) mice carrying either a R26-Stat3(wt) or R26-Stat3(C) allele demonstrated increased a-wave amplitude of the scotopic electroretinogram. Phosphorylation of STAT3 at tyrosine 705 was required for the prosurvival effect because an R26-Stat3(Y705F) allele was not protective. The prosurvival role of enhanced Stat3 activity was validated using recombinant adenoassociated virus (rAAV) vector-mediated PR Stat3 expression in Tg(RHO P347S) mice. Our findings (i) establish that the increase in endogenous PR Stat3 expression is a protective response in IPDs, (ii) suggest that therapeutic augmentation of PR Stat3 expression has potential as a common neuroprotective therapy for these disorders, and (iii) indicate that prosurvival molecules whose expression is increased in mutant PRs may have promise as novel therapies for IPDs.
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Ratnapriya R, Swaroop A. Genetic architecture of retinal and macular degenerative diseases: the promise and challenges of next-generation sequencing. Genome Med 2013; 5:84. [PMID: 24112618 PMCID: PMC4066589 DOI: 10.1186/gm488] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Inherited retinal degenerative diseases (RDDs) display wide variation in their mode of inheritance, underlying genetic defects, age of onset, and phenotypic severity. Molecular mechanisms have not been delineated for many retinal diseases, and treatment options are limited. In most instances, genotype-phenotype correlations have not been elucidated because of extensive clinical and genetic heterogeneity. Next-generation sequencing (NGS) methods, including exome, genome, transcriptome and epigenome sequencing, provide novel avenues towards achieving comprehensive understanding of the genetic architecture of RDDs. Whole-exome sequencing (WES) has already revealed several new RDD genes, whereas RNA-Seq and ChIP-Seq analyses are expected to uncover novel aspects of gene regulation and biological networks that are involved in retinal development, aging and disease. In this review, we focus on the genetic characterization of retinal and macular degeneration using NGS technology and discuss the basic framework for further investigations. We also examine the challenges of NGS application in clinical diagnosis and management.
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Affiliation(s)
- Rinki Ratnapriya
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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23
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Gábriel R. Neuropeptides and diabetic retinopathy. Br J Clin Pharmacol 2013; 75:1189-201. [PMID: 23043302 DOI: 10.1111/bcp.12003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/02/2012] [Indexed: 12/21/2022] Open
Abstract
Diabetic retinopathy, a common complication of diabetes, develops in 75% of patients with type 1 and 50% of patients with type 2 diabetes, progressing to legal blindness in about 5%. In the recent years, considerable efforts have been put into finding treatments for this condition. It has been discovered that peptidergic mechanisms (neuropeptides and their analogues, activating a diverse array of signal transduction pathways through their multiple receptors) are potentially important for consideration in drug development strategies. A considerable amount of knowledge has been accumulated over the last three decades on human retinal neuropeptides and those elements in the pathomechanisms of diabetic retinopathy which might be related to peptidergic signal transduction. Here, human retinal neuropeptides and their receptors are reviewed, along with the theories relevant to the pathogenesis of diabetic retinopathy both in humans and in experimental models. By collating this information, the curative potential of certain neupeptides and their analogues/antagonists can also be discussed, along with the existing clinical treatments of diabetic retinopathy. The most promising peptidergic pathways for which treatment strategies may be developed at present are stimulation of the somatostatin-related pathway and the pituitary adenylyl cyclase-activating polypeptide-related pathway or inhibition of angiotensinergic mechanisms. These approaches may result in the inhibition of vascular endothelial growth factor production and neuronal apoptosis; therefore, both the optical quality of the image and the processing capability of the neural circuit in the retina may be saved.
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Affiliation(s)
- Robert Gábriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, H-7621, Pécs, Hungary.
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Loss of Otx2 in the adult retina disrupts retinal pigment epithelium function, causing photoreceptor degeneration. J Neurosci 2013; 33:9890-904. [PMID: 23761884 DOI: 10.1523/jneurosci.1099-13.2013] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Photoreceptors are specialized neurons of the retina that receive nursing from the adjacent retinal pigment epithelium (RPE). Frequent in the elderly, photoreceptor loss can originate from primary dysfunction of either cell type. Despite intense interest in the etiology of these diseases, early molecular actors of late-onset photoreceptor degeneration remain elusive, mostly because of the lack of dedicated models. Conditional Otx2 ablation in the adult mouse retina elicits photoreceptor degeneration, providing a new model of late-onset neuronal disease. Here, we use this model to identify the earliest events after Otx2 ablation. Electroretinography and gene expression analyses suggest a nonautonomous, RPE-dependent origin for photoreceptor degeneration. This is confirmed by RPE-specific ablation of Otx2, which results in similar photoreceptor degeneration. In contrast, constitutive Otx2 expression in RPE cells prevents degeneration of photoreceptors in Otx2-ablated retinas. We use chromatin immunoprecipitation followed by massive sequencing (ChIP-seq) analysis to identify the molecular network controlled in vivo by Otx2 in RPE cells. We uncover four RPE-specific functions coordinated by Otx2 that underpin the cognate photoreceptor degeneration. Many direct Otx2 target genes are associated with human retinopathies, emphasizing the significance of the model. Importantly, we report a secondary genetic response after Otx2 ablation, which largely precedes apoptosis of photoreceptors, involving inflammation and stress genes. These findings thus provide novel general markers for clinical detection and prevention of neuronal cell death.
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Nishiwaki Y, Yoshizawa A, Kojima Y, Oguri E, Nakamura S, Suzuki S, Yuasa-Kawada J, Kinoshita-Kawada M, Mochizuki T, Masai I. The BH3-only SNARE BNip1 mediates photoreceptor apoptosis in response to vesicular fusion defects. Dev Cell 2013; 25:374-87. [PMID: 23725763 DOI: 10.1016/j.devcel.2013.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 03/15/2013] [Accepted: 04/27/2013] [Indexed: 11/25/2022]
Abstract
Intracellular vesicular transport is important for photoreceptor function and maintenance. However, the mechanism underlying photoreceptor degeneration in response to vesicular transport defects is unknown. Here, we report that photoreceptors undergo apoptosis in a zebrafish β-soluble N-ethylmaleimide-sensitive factor attachment protein (β-SNAP) mutant. β-SNAP cooperates with N-ethylmaleimide-sensitive factor to recycle the SNAP receptor (SNARE), a key component of the membrane fusion machinery, by disassembling the cis-SNARE complex generated in the vesicular fusion process. We found that photoreceptor apoptosis in the β-SNAP mutant was dependent on the BH3-only protein BNip1. BNip1 functions as a component of the syntaxin-18 SNARE complex and regulates retrograde transport from the Golgi to the endoplasmic reticulum. Failure to disassemble the syntaxin-18 cis-SNARE complex caused BNip1-dependent apoptosis. These data suggest that the syntaxin-18 cis-SNARE complex functions as an alarm factor that monitors vesicular fusion competence and that BNip1 transforms vesicular fusion defects into photoreceptor apoptosis.
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Affiliation(s)
- Yuko Nishiwaki
- Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa 904-0412, Japan
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Nojima S, Toyofuku T, Kamao H, Ishigami C, Kaneko J, Okuno T, Takamatsu H, Ito D, Kang S, Kimura T, Yoshida Y, Morimoto K, Maeda Y, Ogata A, Ikawa M, Morii E, Aozasa K, Takagi J, Takahashi M, Kumanogoh A. A point mutation in Semaphorin 4A associates with defective endosomal sorting and causes retinal degeneration. Nat Commun 2013; 4:1406. [PMID: 23360997 PMCID: PMC3562463 DOI: 10.1038/ncomms2420] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 12/20/2012] [Indexed: 12/25/2022] Open
Abstract
Semaphorin 4A (Sema4A) has an essential role in photoreceptor survival. In humans, mutations in Sema4A are thought to contribute to retinal degenerative diseases. Here we generate a series of knock-in mouse lines with corresponding mutations (D345H, F350C or R713Q) in the Sema4A gene and find that Sema4AF350C causes retinal degeneration phenotypes. The F350C mutation results in abnormal localization of the Sema4A protein, leading to impaired endosomal sorting of molecules indispensable for photoreceptor survival. Additionally, protein structural modelling reveals that the side chain of the 350th amino acid is critical to retain the proper protein conformation. Furthermore, Sema4A gene transfer successfully prevents photoreceptor degeneration in Sema4AF350C/F350C and Sema4A−/− mice. Thus, our findings not only indicate the importance of the Sema4A protein conformation in human and mouse retina homeostasis but also identify a novel therapeutic target for retinal degenerative diseases. Semaphorin 4A is implicated in photoreceptor survival. Nojima and colleagues generate transgenic mice with different mutations in the Sema4A gene and find that point mutation of F350 causes severe degeneration in photoreceptor cells, which can be rescued by virus-mediated gene therapy.
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Affiliation(s)
- Satoshi Nojima
- Department of Immunopathology, WPI Immunology Frontier Research Center, Osaka University, Suita City, Osaka 565-0871, Japan
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Bramall AN, Szego MJ, Pacione LR, Chang I, Diez E, D'Orleans-Juste P, Stewart DJ, Hauswirth WW, Yanagisawa M, McInnes RR. Endothelin-2-mediated protection of mutant photoreceptors in inherited photoreceptor degeneration. PLoS One 2013; 8:e58023. [PMID: 23469133 PMCID: PMC3585171 DOI: 10.1371/journal.pone.0058023] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 01/30/2013] [Indexed: 12/21/2022] Open
Abstract
Expression of the Endothelin-2 (Edn2) mRNA is greatly increased in the photoreceptors (PRs) of mouse models of inherited PR degeneration (IPD). To examine the role of Edn2 in mutant PR survival, we generated Edn2−/− mice carrying homozygous Pde6brd1 alleles or the Tg(RHO P347S) transgene. In the Edn2−/− background, PR survival increased 110% in Pde6brd1/rd1 mice at post-natal (PN) day 15, and 60% in Tg(RHO P347S) mice at PN40. In contrast, PR survival was not increased in retinal explants of Pde6brd1/rd1; Edn2−/− mice. This finding, together with systemic abnormalities in Edn2−/− mice, suggested that the increased survival of mutant PRs in the Edn2−/− background resulted at least partly from the systemic EDN2 loss of function. To examine directly the role of EDN2 in mutant PRs, we used a scAAV5-Edn2 cDNA vector to restore Edn2 expression in Pde6brd1/rd1; Edn2−/− PRs and observed an 18% increase in PR survival at PN14. Importantly, PR survival was also increased after injection of scAAV5-Edn2 into Pde6brd1/rd1 retinas, by 31% at PN15. Together, these findings suggest that increased Edn2 expression is protective to mutant PRs. To begin to elucidate Edn2-mediated mechanisms that contribute to PR survival, we used microarray analysis and identified a cohort of 20 genes with >4-fold increased expression in Tg(RHO P347S) retinas, including Fgf2. Notably, increased expression of the FGF2 protein in Tg(RHO P347S) PRs was ablated in Tg(RHO P347S); Edn2−/− retinas. Our findings indicate that the increased expression of PR Edn2 increases PR survival, and suggest that the Edn2-dependent increase in PR expression of FGF2 may contribute to the augmented survival.
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Affiliation(s)
- Alexa N. Bramall
- Program in Developmental Biology, The Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Michael J. Szego
- Program in Developmental Biology, The Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Laura R. Pacione
- Program in Developmental Biology, The Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Inik Chang
- Department of Molecular Genetics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Eduardo Diez
- Lady Davis Research Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | - Pedro D'Orleans-Juste
- Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Duncan J. Stewart
- The Regenerative Medicine Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - William W. Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Masashi Yanagisawa
- Department of Molecular Genetics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Roderick R. McInnes
- Program in Developmental Biology, The Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Lady Davis Research Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Davidson AE, Sergouniotis PI, Mackay DS, Wright GA, Waseem NH, Michaelides M, Holder GE, Robson AG, Moore AT, Plagnol V, Webster AR. RP1L1 variants are associated with a spectrum of inherited retinal diseases including retinitis pigmentosa and occult macular dystrophy. Hum Mutat 2013; 34:506-14. [PMID: 23281133 DOI: 10.1002/humu.22264] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 12/05/2012] [Indexed: 11/09/2022]
Abstract
In one consanguineous family with retinitis pigmentosa (RP), a condition characterized by progressive visual loss due to retinal degeneration, homozygosity mapping, and candidate gene sequencing suggested a novel locus. Exome sequencing identified a homozygous frameshifting mutation, c.601delG, p.Lys203Argfs*28, in RP1L1 encoding RP 1-like1, a photoreceptor-specific protein. A screen of a further 285 unrelated individuals with autosomal recessive RP identified an additional proband, homozygous for a missense variant, c.1637G>C, p.Ser546Thr, in RP1L1. A distinct retinal disorder, occult macular dystrophy (OCMD) solely affects the central retinal cone photoreceptors and has previously been reported to be associated with variants in the same gene. The association between mutations in RP1L1 and the disorder OCMD was explored by screening a cohort of 28 unrelated individuals with the condition; 10 were found to harbor rare (minor allele frequency ≤0.5% in the 1,000 genomes dataset) heterozygous RP1L1 missense variants. Analysis of family members revealed many unaffected relatives harboring the same variant. Linkage analysis excluded the possibility of a recessive mode of inheritance, and sequencing of RP1, a photoreceptor protein that interacts with RP1L1, excluded a digenic mechanism involving this gene. These findings imply an important and diverse role for RP1L1 in human retinal physiology and disease.
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Affiliation(s)
- Alice E Davidson
- University College London Institute of Ophthalmology, London, UK
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Tian Y, Li T, Sun M, Wan D, Li Q, Li P, Zhang Z, Han J, Xie W. Neurexin Regulates Visual Function via Mediating Retinoid Transport to Promote Rhodopsin Maturation. Neuron 2013; 77:311-22. [DOI: 10.1016/j.neuron.2012.11.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2012] [Indexed: 12/22/2022]
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31
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Rezaie T, McKercher SR, Kosaka K, Seki M, Wheeler L, Viswanath V, Chun T, Joshi R, Valencia M, Sasaki S, Tozawa T, Satoh T, Lipton SA. Protective effect of carnosic acid, a pro-electrophilic compound, in models of oxidative stress and light-induced retinal degeneration. Invest Ophthalmol Vis Sci 2012; 53:7847-54. [PMID: 23081978 DOI: 10.1167/iovs.12-10793] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PURPOSE The herb rosemary has been reported to have antioxidant and anti-inflammatory activity. We have previously shown that carnosic acid (CA), present in rosemary extract, crosses the blood-brain barrier to exert neuroprotective effects by upregulating endogenous antioxidant enzymes via the Nrf2 transcriptional pathway. Here we investigated the antioxidant and neuroprotective activity of CA in retinal cell lines exposed to oxidative stress and in a rat model of light-induced retinal degeneration (LIRD). METHODS Retina-derived cell lines ARPE-19 and 661W treated with hydrogen peroxide were used as in vitro models for testing the protective activity of CA. For in vivo testing, dark-adapted rats were given intraperitoneal injections of CA prior to exposure to white light to assess protection of the photoreceptor cells. Retinal damage was assessed by measuring outer nuclear layer thickness and by electroretinogram (ERG). RESULTS In vitro, CA significantly protected retina-derived cell lines (ARPE-19 and 661W) against H(2)O(2)-induced toxicity. CA induced antioxidant phase 2 enzymes and reduced formation of hyperoxidized peroxiredoxin (Prx)2. Similarly, we found that CA protected retinas in vivo from LIRD, producing significant improvement in outer nuclear layer thickness and ERG activity. CONCLUSIONS These findings suggest that CA may potentially have clinical application to diseases affecting the outer retina, including age-related macular degeneration and retinitis pigmentosa, in which oxidative stress is thought to contribute to disease progression.
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Affiliation(s)
- Tayebeh Rezaie
- Del E Web Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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Toyofuku T, Nojima S, Ishikawa T, Takamatsu H, Tsujimura T, Uemura A, Matsuda J, Seki T, Kumanogoh A. Endosomal sorting by Semaphorin 4A in retinal pigment epithelium supports photoreceptor survival. Genes Dev 2012; 26:816-29. [PMID: 22465952 DOI: 10.1101/gad.184481.111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Photoreceptor cell death is the hallmark of a group of human inherited retinal degeneration. Although the causative genetic mutations are often known, the mechanisms leading to photoreceptor degeneration remain poorly defined. Here, we show that Semaphorin 4A (Sema4A), a member of axonal guidance molecule semaphorin, plays a role in Rab11/FIP2-mediated endosomal sorting in retinal pigment epithelial cells to support photoreceptor function. In response to oxidative stress, Sema4A switches the endosomal sorting of the lysosomal precursor protein prosaposin from the lysosome to the exosomal release, which prevents light-induced photoreceptor apoptosis. In the absence of oxidative stress, Sema4A sorts retinoid-binding proteins with retinoids between the cell surface and endoplasmic reticulum, by which 11-cis-retinal, a chromophore for phototransduction, is regenerated and transported back to photoreceptors. Owing to defects in these processes, Sema4A-deficient mice exhibit marked photoreceptor degeneration. Our findings therefore indicate that Sema4A regulates two distinct endosomal-sorting pathways that are critical for photoreceptor survival and phototransduction during the transition between daylight and darkness.
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Affiliation(s)
- Toshihiko Toyofuku
- World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.
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Alternative pathway of cell death in Drosophila mediated by NF-κB transcription factor Relish. Proc Natl Acad Sci U S A 2012; 109:E605-12. [PMID: 22328149 DOI: 10.1073/pnas.1110666109] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Photoreceptor cell death accompanying many retinal degenerative disorders results in irreversible loss of vision in humans. However, the precise molecular pathway that executes cell death is not known. Our results from a Drosophila model of retinal degeneration corroborate previously reported findings that the developmental apoptotic pathway is not involved in photoreceptor cell demise. By undertaking a candidate gene approach, we find that players involved in the immune response against gram-negative bacteria are involved in retinal degeneration. Here, we report that the NF-κB transcription factor Relish regulates neuronal cell death. Retinal degeneration is prevented in genetic backgrounds that block Relish activation. We also report that the N-terminal domain of Relish encodes unique toxic functions. These data uncover a unique molecular pathway of retinal degeneration in Drosophila and identify a previously unknown function of NF-κB signaling in cell death.
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Kirk SR, Andrade AL, Melich K, Jackson EP, Cuellar E, Karpen JW. Halogen substituents on the aromatic moiety of the tetracaine scaffold improve potency of cyclic nucleotide-gated channel block. Bioorg Med Chem Lett 2011; 21:6417-9. [DOI: 10.1016/j.bmcl.2011.08.092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 08/19/2011] [Indexed: 11/28/2022]
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35
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Phosphorylation/inactivation of PTEN by Akt-independent PI3K signaling in retinal pigment epithelium. Biochem Biophys Res Commun 2011; 414:384-9. [PMID: 21964287 DOI: 10.1016/j.bbrc.2011.09.083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 09/15/2011] [Indexed: 11/20/2022]
Abstract
Retinal pigment epithelium (RPE) plays a critical role in vertebrate vision by providing functional and structural support to the retina. Degeneration of RPE by cumulative oxidative stresses or acute injury frequently results in retinal degenerative diseases, notably age-related macular degeneration (AMD). Moreover, it has been shown that phosphorylation-mediated inactivation of PTEN (phosphatase and tensin homolog) in RPE is closely linked to AMD-like retinal degeneration in mice [1]. In this study, we used AMD mouse models, in which chemokine (C-C motif) ligand 2 (Ccl2) or chemokine (C-C motif) receptor 2 (Ccr2) were genetically ablated, to examine mechanisms linking reactive oxygen species (ROS) to phosphorylation/inactivation of PTEN in RPE. We found that ROS levels were increased in these RPE cells in association with phosphorylation/inactivation of PTEN. Both PTEN phosphorylation/inactivation and consequent Akt activation in the RPE of AMD model mice were inhibited by antioxidant treatment, indicating a functional role for elevated intracellular ROS. We further discovered that PTEN phosphorylation in oxidatively stressed RPE was repressed by a phosphoinositide 3-kinase (PI3K) inhibitor, but not by an Akt inhibitor. Taken together, these results suggest that ROS-activated PI3K potentiates AMD-related RPE pathogenesis through phosphorylation/inactivation of PTEN.
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36
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Non-invasive anterior segment and posterior segment optical coherence tomography and phenotypic characterization of aniridia. Can J Ophthalmol 2011; 46:337-44. [DOI: 10.1016/j.jcjo.2011.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/11/2011] [Accepted: 04/11/2011] [Indexed: 11/22/2022]
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37
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Andrade AL, Melich K, Whatley GG, Kirk SR, Karpen JW. Cyclic nucleotide-gated channel block by hydrolysis-resistant tetracaine derivatives. J Med Chem 2011; 54:4904-12. [PMID: 21634421 DOI: 10.1021/jm200495g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
To meet a pressing need for better cyclic nucleotide-gated (CNG) channel antagonists, we have increased the biological stability of tetracaine-based blockers by synthesizing amide and thioamide linkage substitutions of tetracaine (1) and a higher affinity octyl tail derivative (5). We report the apparent K(D) values, the mechanism of block, and the in vitro hydrolysis rates for these compounds. The ester linkage substitutions did not adversely affect CNG channel block; unexpectedly, thioamide substitution in 1 (compound 8) improved block significantly. Furthermore, the ester linkage substitutions did not appear to affect the mechanism of block in terms of the strong state preference for closed channels. All ester substituted compounds, especially the thioamide substitutions, were more resistant to hydrolysis by serum cholinesterase than their ester counterparts. These findings have implications for dissecting the physiological roles of CNG channels, treating certain forms of retinal degeneration, and possibly the current clinical uses of compound 1.
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Affiliation(s)
- Adriana L Andrade
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239, United States
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38
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Yu B, Fey P, Kestin-Pilcher KE, Fedorov A, Prakash A, Chisholm RL, Wu JY. Spliceosomal genes in the D. discoideum genome: a comparison with those in H. sapiens, D. melanogaster, A. thaliana and S. cerevisiae. Protein Cell 2011; 2:395-409. [PMID: 21667333 DOI: 10.1007/s13238-011-1052-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 05/20/2011] [Indexed: 02/05/2023] Open
Abstract
Little is known about pre-mRNA splicing in Dictyostelium discoideum although its genome has been completely sequenced. Our analysis suggests that pre-mRNA splicing plays an important role in D. discoideum gene expression as two thirds of its genes contain at least one intron. Ongoing curation of the genome to date has revealed 40 genes in D. discoideum with clear evidence of alternative splicing, supporting the existence of alternative splicing in this unicellular organism. We identified 160 candidate U2-type spliceosomal proteins and related factors in D. discoideum based on 264 known human genes involved in splicing. Spliceosomal small ribonucleoproteins (snRNPs), PRP19 complex proteins and late-acting proteins are highly conserved in D. discoideum and throughout the metazoa. In non-snRNP and hnRNP families, D. discoideum orthologs are closer to those in A. thaliana, D. melanogaster and H. sapiens than to their counterparts in S. cerevisiae. Several splicing regulators, including SR proteins and CUG-binding proteins, were found in D. discoideum, but not in yeast. Our comprehensive catalog of spliceosomal proteins provides useful information for future studies of splicing in D. discoideum where the efficient genetic and biochemical manipulation will also further our general understanding of pre-mRNA splicing.
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Affiliation(s)
- Bing Yu
- Department of Molecular and Clinical Genetics, Royal Prince Alfred Hospital and Sydney Medical School (Central), the University of Sydney, Australia
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Bramall AN, Wright AF, Jacobson SG, McInnes RR. The genomic, biochemical, and cellular responses of the retina in inherited photoreceptor degenerations and prospects for the treatment of these disorders. Annu Rev Neurosci 2011; 33:441-72. [PMID: 20572772 DOI: 10.1146/annurev-neuro-060909-153227] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The association of more than 140 genes with human photoreceptor degenerations, together with studies of animal models of these monogenic diseases, has provided great insight into their pathogenesis. Here we review the responses of the retina to photoreceptor mutations, including mechanisms of photoreceptor death. We discuss the roles of oxidative metabolism, mitochondrial reactive oxygen species, metabolic stress, protein misfolding, and defects in ciliary proteins, as well as the responses of Müller glia, microglia, and the retinal vasculature. Finally, we report on potential pharmacologic and biologic therapies, the critical role of histopathology as a prerequisite to treatment, and the exciting promise of gene therapy in animal models and in phase 1 trials in humans.
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Affiliation(s)
- Alexa N Bramall
- Programs in Genetics and Developmental Biology, The Research Institute, The Hospital for Sick Children, Toronto M5G1L7, Canada.
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40
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Rod photoreceptor cell death is induced by okadaic acid through activation of PKC and L-type voltage-dependent Ca2+ channels and prevented by IGF-1. Neurochem Int 2010; 57:128-35. [DOI: 10.1016/j.neuint.2010.04.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 04/14/2010] [Accepted: 04/29/2010] [Indexed: 02/02/2023]
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41
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Molday RS, Zhang K. Defective lipid transport and biosynthesis in recessive and dominant Stargardt macular degeneration. Prog Lipid Res 2010; 49:476-92. [PMID: 20633576 DOI: 10.1016/j.plipres.2010.07.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Stargardt disease is a common inherited macular degeneration characterized by a significant loss in central vision in the first or second decade of life, bilateral atrophic changes in the central retina associated with degeneration of photoreceptors and underlying retinal pigment epithelial cells, and the presence of yellow flecks extending from the macula. Autosomal recessive Stargardt disease, the most common macular dystrophy, is caused by mutations in the gene encoding ABCA4, a photoreceptor ATP binding cassette (ABC) transporter. Biochemical studies together with analysis of abca4 knockout mice and Stargardt patients have implicated ABCA4 as a lipid transporter that facilitates the removal of potentially toxic retinal compounds from photoreceptors following photoexcitation. An autosomal dominant form of Stargardt disease also known as Stargardt-like dystrophy is caused by mutations in a gene encoding ELOVL4, an enzyme that catalyzes the elongation of very long-chain fatty acids in photoreceptors and other tissues. This review focuses on the molecular characterization of ABCA4 and ELOVL4 and their role in photoreceptor cell biology and the pathogenesis of Stargardt disease.
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Affiliation(s)
- Robert S Molday
- Department of Biochemistry and Molecular Biology, Centre of Macular Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada.
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Abstract
A pressing need for interrater reliability in the diagnosis of mental disorders emerged during the mid-twentieth century, prompted in part by the development of diverse new treatments. The Diagnostic and Statistical Manual of Mental Disorders (DSM), third edition answered this need by introducing operationalized diagnostic criteria that were field-tested for interrater reliability. Unfortunately, the focus on reliability came at a time when the scientific understanding of mental disorders was embryonic and could not yield valid disease definitions. Based on accreting problems with the current DSM-fourth edition (DSM-IV) classification, it is apparent that validity will not be achieved simply by refining criteria for existing disorders or by the addition of new disorders. Yet DSM-IV diagnostic criteria dominate thinking about mental disorders in clinical practice, research, treatment development, and law. As a result, the modern DSM system, intended to create a shared language, also creates epistemic blinders that impede progress toward valid diagnoses. Insights that are beginning to emerge from psychology, neuroscience, and genetics suggest possible strategies for moving forward.
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Affiliation(s)
- Steven E Hyman
- Department of Neurobiology, Harvard Medical School, Harvard University, Cambridge, Massachusetts 02138, USA.
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Wright AF, Chakarova CF, Abd El-Aziz MM, Bhattacharya SS. Photoreceptor degeneration: genetic and mechanistic dissection of a complex trait. Nat Rev Genet 2010; 11:273-84. [PMID: 20212494 DOI: 10.1038/nrg2717] [Citation(s) in RCA: 445] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Coleman JA, Kwok MCM, Molday RS. Localization, purification, and functional reconstitution of the P4-ATPase Atp8a2, a phosphatidylserine flippase in photoreceptor disc membranes. J Biol Chem 2009; 284:32670-9. [PMID: 19778899 DOI: 10.1074/jbc.m109.047415] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
P(4)-ATPases comprise a relatively new subfamily of P-type ATPases implicated in the energy-dependent translocation of aminophospholipids across cell membranes. In this study, we report on the localization and functional properties of Atp8a2, a member of the P(4)-ATPase subfamily that has not been studied previously. Reverse transcription-PCR revealed high expression of atp8a2 mRNA in the retina and testis. Within the retina, immunofluorescence microscopy and subcellular fractionation studies localized Atp8a2 to outer segment disc membranes of rod and cone photoreceptor cells. Atp8a2 purified from photoreceptor outer segments by immunoaffinity chromatography exhibited ATPase activity that was stimulated by phosphatidylserine and to a lesser degree phosphatidylethanolamine but not by phosphatidylcholine or other membrane lipids. Purified Atp8a2 was reconstituted into liposomes containing fluorescent-labeled phosphatidylserine to measure the ability of Atp8a2 to flip phosphatidylserine across the lipid bilayer. Fluorescence measurements showed that Atp8a2 flipped fluorescent-labeled phosphatidylserine from the inner leaflet of liposomes (equivalent to the exocytoplasmic leaflet of cell membranes) to the outer leaflet (equivalent to cytoplasmic leaflet) in an ATP-dependent manner. Our studies provide the first direct biochemical evidence that purified P(4)-ATPases can translocate aminophospholipids across membranes and further implicates Atp8a2 in the generation and maintenance of phosphatidylserine asymmetry in photoreceptor disc membranes.
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Affiliation(s)
- Jonathan A Coleman
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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45
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Marmorstein AD, Cross HE, Peachey NS. Functional roles of bestrophins in ocular epithelia. Prog Retin Eye Res 2009; 28:206-26. [PMID: 19398034 DOI: 10.1016/j.preteyeres.2009.04.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
There are four members of the bestrophin family of proteins in the human genome, of which two are known to be expressed in the eye. The gene BEST1 (formerly VMD2) which encodes the protein bestrophin-1 (Best1) was first identified in 1998. Mutations in this gene have now been associated with four clinically distinguishable human eye diseases, collectively referred to as "bestrophinopathies". Over the last decade, laboratories have sought to understand how Best1 mutations could result in eye diseases that range in presentation from macular degeneration to nanophthalmos. The majority of our knowledge comes from studies that have sought to understand how Best1 mutations or dysfunction could induce the classical symptoms of the most common of these diseases: Best vitelliform macular dystrophy (BVMD). BVMD is a dominant trait that is characterized electrophysiologically by a diminished electrooculogram light peak with a normal clinical electroretinogram. This together with the localization of Best1 to the retinal pigment epithelium (RPE) basolateral plasma membrane and data from heterologous expression studies, have led to the proposal that Best1 generates the light peak, and that bestrophins are a family of Ca(2+) activated Cl(-) channels (CaCCs). However, data from Best1 knock-out and knock-in mice, coupled with the recent discovery of a recessive bestrophinopathy suggest that Best1 does not generate the light peak. Recently Best2 was found to be expressed in non-pigmented epithelia in the ciliary body. However, aqueous dynamics in Best2 knock-out mice do not support a role for Best2 as a Cl(-) channel. Thus, the purported CaCC function of the bestrophins and how loss of this function relates to clinical disease needs to be reassessed. In this article, we examine data obtained from tissue-type and animal models and discuss the current state of bestrophin research, what roles Best1 and Best2 may play in ocular epithelia and ocular electrophysiology, and how perturbation of these functions may result in disease.
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Affiliation(s)
- Alan D Marmorstein
- Department of Ophthalmology and Vision Science, University of Arizona, Tucson, AZ 85711, USA.
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Kang KH, Lemke G, Kim JW. The PI3K-PTEN tug-of-war, oxidative stress and retinal degeneration. Trends Mol Med 2009; 15:191-8. [PMID: 19380252 DOI: 10.1016/j.molmed.2009.03.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 03/06/2009] [Accepted: 03/06/2009] [Indexed: 01/01/2023]
Abstract
The retinal pigment epithelium (RPE) is indispensable for photoreceptor function, not only because it provides functional photopigments to photoreceptors, but also because it eliminates oxidatively damaged materials from photoreceptors. Maintaining homeostatic antioxidative programs that support a healthy RPE is therefore important for the normal functioning of the eye. These homeostatic mechanisms, however, often fail in aged RPE cells that have been exposed repeatedly to excessive oxidative stress. When RPE cells succumb to oxidative stress, their death contributes to the development of retinal degenerative diseases such as age-related macular degeneration. Recent studies have highlighted the importance of reciprocal phosphoinositide signaling events orchestrated by phosphoinositide 3-kinase (PI3K) and phosphatase and tensin homolog (PTEN) in the homeostatic programs that protect RPE cells against oxidative stress. Here, we discuss the role of PI3K signaling pathways in RPE cells and suggest that they might be crucial targets of oxidative molecules that initiate early pathological events in retinal degenerative diseases.
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Affiliation(s)
- Kyung Hwa Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, South Korea
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Chapter 7 Biology and Functions of the RGS9 Isoforms. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 86:205-27. [DOI: 10.1016/s1877-1173(09)86007-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Abstract
Understanding the pathogenesis of neuropsychiatric disorders is a substantial challenge for neurobiologists. It has long been hoped that identifying alleles that confer increased risk of such disorders would provide clues for neurobiological investigation. But this quest has been stymied by a lack of validated biological markers for characterizing and distinguishing the different disorders and by the genetic complexity underpinning these diseases. Now, modern genomic technologies have begun to facilitate the discovery of relevant genes.
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Cho KI, Yi H, Yeh A, Tserentsoodol N, Cuadrado L, Searle K, Hao Y, Ferreira PA. Haploinsufficiency of RanBP2 is neuroprotective against light-elicited and age-dependent degeneration of photoreceptor neurons. Cell Death Differ 2008; 16:287-97. [PMID: 18949001 DOI: 10.1038/cdd.2008.153] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Prolonged light exposure is a determinant factor in inducing neurodegeneration of photoreceptors by apoptosis. Yet, the molecular bases of the pathways and components triggering this cell death event are elusive. Here, we reveal a prominent age-dependent increase in the susceptibility of photoreceptor neurons to undergo apoptosis under light in a mouse model. This is accompanied by light-induced subcellular changes of photoreceptors, such as dilation of the disks at the tip of the outer segments, prominent vesiculation of nascent disks, and autophagy of mitochondria into large multilamellar bodies. Notably, haploinsufficiency of Ran-binding protein-2 (RanBP2) suppresses apoptosis and most facets of membrane dysgenesis observed with age upon light-elicited stress. RanBP2 haploinsufficiency promotes decreased levels of free fatty acids in the retina independent of light exposure and turns the mice refractory to weight gain on a high-fat diet, whereas light promotes an increase in hydrogen peroxide regardless of the genotype. These studies demonstrate the presence of age-dependent and RanBP2-mediated pathways modulating membrane biogenesis of the outer segments and light-elicited neurodegeneration of photoreceptors. Furthermore, the findings support a mechanism whereby the RanBP2-dependent production of free fatty acids, metabolites thereof or the modulation of a cofactor dependent on any of these, promote apoptosis of photoreceptors in concert with the light-stimulated production of reactive oxygen species.
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Affiliation(s)
- K-in Cho
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
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Abstract
The auxiliary spliceosomal protein SCNM1 contributes to recognition of nonconsensus splice donor sites. SCNM1 was first identified as a modifier of the severity of a sodium channelopathy in the mouse. The most severely affected strain, C57BL/6J, carries the variant allele SCNM1R187X, which is defective in splicing the mutated donor site in the Scn8a(medJ) transcript. To further probe the in vivo function of SCNM1, we constructed a floxed allele and generated a mouse with constitutive deletion of exons 3-5. The SCNM1Delta3-5 protein is produced and correctly localized to the nucleus, but is more functionally impaired than the C57BL/6J allele. Deficiency of SCNM1 did not significantly alter other brain transcripts. We characterized an ENU-induced allele of Scnm1 and evaluated the ability of wild-type SCNM1 to rescue lethal mutations of I-mfa and Brunol4. The phenotypes of the Scnm1Delta3-5 mutant confirm the role of this splice factor in processing the Scn8a(medJ) transcript and provide a new allele of greater severity for future studies.
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