1
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Ling F, Zhang C, Zhao X, Xin X, Zhao S. Identification of key genes modules linking diabetic retinopathy and circadian rhythm. Front Immunol 2023; 14:1260350. [PMID: 38124748 PMCID: PMC10730663 DOI: 10.3389/fimmu.2023.1260350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023] Open
Abstract
Background Diabetic retinopathy (DR) is a leading cause of vision loss worldwide. Recent studies highlighted the crucial impact of circadian rhythms (CR) on normal retinopathy in response to the external light cues. However, the role of circadian rhythms in DR pathogenesis and potential investigational drugs remains unclear. Methods To investigate the weather CR affects DR, differential expression analysis was employed to identify differentially expressed genes (DEGs) from the GEO database (GSE160306). Functional enrichment analysis was conducted to identify relevant signaling pathways. LASSO regression was utilized to screen pivotal genes. Weighted gene co-expression network anlaysis (WGCNA) was applied to identify different modules. Additionally, we use the Comparative Toxicogenomics Database (CTD) database to search key genes related to drugs or molecular compounds. The diabetic mouse model received three consecutive intraperitoneal injections of streptozotocin (STZ) during 3 successive days. Results We initially identified six key genes associated with circadian rhythm in DR, including COL6A3, IGFBP2, IGHG4, KLHDC7A, RPL26P30, and MYL6P4. Compared to normal tissue, the expression levels of COL6A3 and IGFB2 were significantly increased in DR model. Furthermore, we identified several signaling pathways, including death domain binding, insulin-like growth factor I binding, and proteasome binding. We also observed that COL6A3 was positively correlated with macrophages (cor=0.628296895, p=9.96E-08) and Th17 cells (cor=0.665120835, p=9.14E-09), while IGFBP2 showed a negatively correlated with Tgd (cor=-0.459953045, p=0.000247284) and Th2 cells (cor=-0.442269719, p=0.000452875). Finally, we identified four drugs associated with key genes: Resveratrol, Vitamin E, Streptozocin, and Sulindac. Conclusion Our findings revealed several key genes related to circadian rhythms and several relevant drugs in DR, providing a novel insight into the mechanism of DR and potential implications for future DR treatment. This study contributes to a better understanding of CR in DR and its implications for future therapeutic interventions.
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Affiliation(s)
- Feng Ling
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Caijie Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Xin Zhao
- Department of Ophthalmology, Inner Mongolia Baogang Hospita, Inner Mongolia, Baotou, China
| | - Xiangyang Xin
- Department of Ophthalmology, Inner Mongolia Baogang Hospita, Inner Mongolia, Baotou, China
| | - Shaozhen Zhao
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
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2
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Wei R, Chen Q, Zheng Q, Reinach PS, Tan X, Pan C, Xu W, Tong L, Chen W. Epigenetic Activation of Circadian Clock Genes Elicits Inflammation in Experimental Murine Dry Eye. Ocul Immunol Inflamm 2023:1-9. [PMID: 37163389 DOI: 10.1080/09273948.2023.2205525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
PURPOSE To explore whether circadian clock genes contribute to elicit inflammation in experimental dry eye (EDE). METHODS RNA sequencing analyzed mRNA expression patterns in EDE model. RT-qPCR and/or Western blot determined the expression of inflammatory factors and circadian genes during EDE. MethylTarget™ assays determined the promoter methylation levels of Per genes in vivo. Per2 or Per3 knockdown assessed their effects on inflammatory factors in vitro. RESULTS We utilized an intelligently controlled environmental system (ICES) to establish a mouse EDE model. The significant upregulated genes were enriched for circadian rhythms. Therein lied oscillatory and time-dependent upregulation of PER2 and PER3, as well as their promoter hypomethylation during EDE. Silencing PER2 or PER3 significantly decreased inflammatory factor expression and also reversed such increased inflammatory response in azacitidine (AZA) treatment in vitro model. CONCLUSIONS Our findings suggest that DNA methylation mediated the upregulation of PER2 and PER3, leading to inflammatory response in EDE.
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Affiliation(s)
- Ruifen Wei
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qianqian Chen
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qinxiang Zheng
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Peter S Reinach
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiying Tan
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Chengjie Pan
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Wei Xu
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Louis Tong
- Singapore Eye Research Institute, Singapore; Singapore National Eye Centre, Singapore; Duke-NUS Medical School, Singapore; Yong Loo Lin School of Medicine, Singapore; National University of Singapore, Singapore
| | - Wei Chen
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
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3
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Abstract
Visual information processing in the retina requires the rhythmic expression of clock genes. The intrinsic retinal circadian clock is independent of the master clock located in the hypothalamic suprachiasmatic nucleus and emerges from retinal cells, including glia. Less clear is how glial oscillators influence the daily regulation of visual information processing in the mouse retina. Here, we demonstrate that the adult conditional deletion of the gene Bmal1 in GLAST-positive glial cells alters retinal physiology. Specifically, such deletion was sufficient to lower the amplitude of the electroretinogram b-wave recorded under light-adapted conditions. Furthermore, recordings from > 20,000 retinal ganglion cells (RGCs), the retina output, showed a non-uniform effect on RGCs activity in response to light across different cell types and over a 24-h period. Overall, our results suggest a new role of a glial circadian gene in adjusting mammalian retinal output throughout the night-day cycle.
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4
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Baba K, Suen TC, Goyal V, Stowie A, Davidson A, DeBruyne J, Tosini G. The circadian clock mediates the response to oxidative stress in a cone photoreceptor‒like (661W) cell line via regulation of glutathione peroxidase activity. F1000Res 2022; 11:1072. [PMID: 36405557 PMCID: PMC9639596 DOI: 10.12688/f1000research.125133.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/16/2022] [Indexed: 11/23/2022] Open
Abstract
Background: The mammalian retina contains an autonomous circadian clock that controls many physiological functions within this tissue. Our previous studies have indicated that disruption of this circadian clock by removing Bmal1 from the retina affects the visual function, retinal circuitry, and cone photoreceptor viability during aging. In the present study, we employed a mouse-derived cone photoreceptor‒like cell, 661W, to investigate which molecular mechanisms of the circadian clock may modulate cone photoreceptor viability during aging. Methods: Bmal1 knockout (BKO) cells were generated from 661W cells using the CRISPR/Cas9 gene editing tool. Deletion of Bmal1 from 661W was verified by western blot and monitoring Per2-luc bioluminescence circadian rhythms. To investigate the effect of Bmal1 removal on an oxidative stress challenge, cells were treated with hydrogen peroxide (H 2O 2,1 mM) for two hours and then cell viability was assessed. Cells were also cultured and harvested for gene expression analysis and antioxidant assay. Results: Our data indicated that 661W cells contain a functional circadian clock that mediates the response to an oxidative stress challenge in vitro and that such a response is no longer present in the BKO cell. We also hypothesized that the effect was due to the circadian regulation of the intracellular antioxidant defense mechanism. Our results revealed that in 661W cells, the antioxidant defense mechanism showed time dependent variation , whereas in BKO cells, there was an overall reduction in this antioxidant defense mechanism, and it no longer showed time dependent variation. Conclusions: Our work supported the notion that the presence of a functional circadian clock and its ability to modulate the response to an oxidative stress is the underlying mechanism that may protect cones during aging.
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Affiliation(s)
- Kenkichi Baba
- Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,
| | - Ting-Chung Suen
- Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA
| | - Varunika Goyal
- Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA
| | - Adam Stowie
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA
| | - Alec Davidson
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA
| | - Jason DeBruyne
- Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA
| | - Gianluca Tosini
- Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA,Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, 30310, USA
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5
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Circadian Regulation of Retinal Pigment Epithelium Function. Int J Mol Sci 2022; 23:ijms23052699. [PMID: 35269840 PMCID: PMC8910459 DOI: 10.3390/ijms23052699] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 12/22/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a single layer of cells located between the choriocapillaris vessels and the light-sensitive photoreceptors in the outer retina. The RPE performs physiological processes necessary for the maintenance and support of photoreceptors and visual function. Among the many functions performed by the RPE, the timing of the peak in phagocytic activity by the RPE of the photoreceptor outer segments that occurs 1-2 h. after the onset of light has captured the interest of many investigators and has thus been intensively studied. Several studies have shown that this burst in phagocytic activity by the RPE is under circadian control and is present in nocturnal and diurnal species and rod and cone photoreceptors. Previous investigations have demonstrated that a functional circadian clock exists within multiple retinal cell types and RPE cells. However, the anatomical location of the circadian controlling this activity is not clear. Experimental evidence indicates that the circadian clock, melatonin, dopamine, and integrin signaling play a key role in controlling this rhythm. A series of very recent studies report that the circadian clock in the RPE controls the daily peak in phagocytic activity. However, the loss of the burst in phagocytic activity after light onset does not result in photoreceptor or RPE deterioration during aging. In the current review, we summarized the current knowledge on the mechanism controlling this phenomenon and the physiological role of this peak.
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6
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Fishman ES, Han JS, La Torre A. Oscillatory Behaviors of microRNA Networks: Emerging Roles in Retinal Development. Front Cell Dev Biol 2022; 10:831750. [PMID: 35186936 PMCID: PMC8847441 DOI: 10.3389/fcell.2022.831750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/07/2022] [Indexed: 01/02/2023] Open
Abstract
A broad repertoire of transcription factors and other genes display oscillatory patterns of expression, typically ranging from 30 min to 24 h. These oscillations are associated with a variety of biological processes, including the circadian cycle, somite segmentation, cell cycle, and metabolism. These rhythmic behaviors are often prompted by transcriptional feedback loops in which transcriptional activities are inhibited by their corresponding gene target products. Oscillatory transcriptional patterns have been proposed as a mechanism to drive biological clocks, the molecular machinery that transforms temporal information into accurate spatial patterning during development. Notably, several microRNAs (miRNAs) -small non-coding RNA molecules-have been recently shown to both exhibit rhythmic expression patterns and regulate oscillatory activities. Here, we discuss some of these new findings in the context of the developing retina. We propose that miRNA oscillations are a powerful mechanism to coordinate signaling pathways and gene expression, and that addressing the dynamic interplay between miRNA expression and their target genes could be key for a more complete understanding of many developmental processes.
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7
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Bery A, Bagchi U, Bergen AA, Felder-Schmittbuhl MP. Circadian clocks, retinogenesis and ocular health in vertebrates: new molecular insights. Dev Biol 2022; 484:40-56. [DOI: 10.1016/j.ydbio.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/21/2022] [Accepted: 02/01/2022] [Indexed: 12/22/2022]
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8
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Endogenous functioning and light response of the retinal clock in vertebrates. PROGRESS IN BRAIN RESEARCH 2022; 273:49-69. [DOI: 10.1016/bs.pbr.2022.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Yang C, Georgiou M, Atkinson R, Collin J, Al-Aama J, Nagaraja-Grellscheid S, Johnson C, Ali R, Armstrong L, Mozaffari-Jovin S, Lako M. Pre-mRNA Processing Factors and Retinitis Pigmentosa: RNA Splicing and Beyond. Front Cell Dev Biol 2021; 9:700276. [PMID: 34395430 PMCID: PMC8355544 DOI: 10.3389/fcell.2021.700276] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 07/09/2021] [Indexed: 12/20/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most common inherited retinal disease characterized by progressive degeneration of photoreceptors and/or retinal pigment epithelium that eventually results in blindness. Mutations in pre-mRNA processing factors (PRPF3, 4, 6, 8, 31, SNRNP200, and RP9) have been linked to 15–20% of autosomal dominant RP (adRP) cases. Current evidence indicates that PRPF mutations cause retinal specific global spliceosome dysregulation, leading to mis-splicing of numerous genes that are involved in a variety of retina-specific functions and/or general biological processes, including phototransduction, retinol metabolism, photoreceptor disk morphogenesis, retinal cell polarity, ciliogenesis, cytoskeleton and tight junction organization, waste disposal, inflammation, and apoptosis. Importantly, additional PRPF functions beyond RNA splicing have been documented recently, suggesting a more complex mechanism underlying PRPF-RPs driven disease pathogenesis. The current review focuses on the key RP-PRPF genes, depicting the current understanding of their roles in RNA splicing, impact of their mutations on retinal cell’s transcriptome and phenome, discussed in the context of model species including yeast, zebrafish, and mice. Importantly, information on PRPF functions beyond RNA splicing are discussed, aiming at a holistic investigation of PRPF-RP pathogenesis. Finally, work performed in human patient-specific lab models and developing gene and cell-based replacement therapies for the treatment of PRPF-RPs are thoroughly discussed to allow the reader to get a deeper understanding of the disease mechanisms, which we believe will facilitate the establishment of novel and better therapeutic strategies for PRPF-RP patients.
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Affiliation(s)
- Chunbo Yang
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Maria Georgiou
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert Atkinson
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Joseph Collin
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jumana Al-Aama
- Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Colin Johnson
- Leeds Institute of Molecular Medicine, University of Leeds, Leeds, United Kingdom
| | - Robin Ali
- King's College London, London, United Kingdom
| | - Lyle Armstrong
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Sina Mozaffari-Jovin
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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10
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Bhatwadekar AD, Rameswara V. Circadian rhythms in diabetic retinopathy: an overview of pathogenesis and investigational drugs. Expert Opin Investig Drugs 2020; 29:1431-1442. [PMID: 33107770 DOI: 10.1080/13543784.2020.1842872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Circadian rhythm is a natural endogenous process occurring roughly every 24 hours. Circadian rhythm dysfunction is involved in diabetic retinopathy (DR) pathogenesis. Interestingly, there are investigational drugs that exhibit potential in the treatment of DR by targeting circadian rhythm dysfunction. AREAS COVERED We performed a literature search in June 2020 using PubMed's Medical Subject Heading (MeSH) terms 'circadian clock,' 'circadian rhythms,' and 'diabetic retinopathy.' This article offers an overview of the physiology of the biological clock and clock regulatory genes and presents an examination of the retinal clock. It discusses the pathogenic mechanisms of DR and emphasizes how circadian rhythm dysfunction at structural, physiological, metabolic and cellular levels, plays a critical role in the development of DR. The latter part of the paper sheds light on those investigational drugs (such as melatonin, tasimelteon and metformin) which exhibit potential in the treatment of DR by the targeting of circadian rhythm dysfunction. EXPERT OPINION An enhanced understanding of circadian rhythm and its role in DR could offer therapeutic potential by targeting of circadian rhythm dysfunction.
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Affiliation(s)
- Ashay D Bhatwadekar
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute , Indianapolis, IN, USA
| | - Varun Rameswara
- Indiana University School of Medicine. Indiana University , Indianapolis, IN, USA
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11
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Bedont JL, Iascone DM, Sehgal A. The Lineage Before Time: Circadian and Nonclassical Clock Influences on Development. Annu Rev Cell Dev Biol 2020; 36:469-509. [PMID: 33021821 PMCID: PMC10826104 DOI: 10.1146/annurev-cellbio-100818-125454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Diverse factors including metabolism, chromatin remodeling, and mitotic kinetics influence development at the cellular level. These factors are well known to interact with the circadian transcriptional-translational feedback loop (TTFL) after its emergence. What is only recently becoming clear, however, is how metabolism, mitosis, and epigenetics may become organized in a coordinated cyclical precursor signaling module in pluripotent cells prior to the onset of TTFL cycling. We propose that both the precursor module and the TTFL module constrain cellular identity when they are active during development, and that the emergence of these modules themselves is a key lineage marker. Here we review the component pathways underlying these ideas; how proliferation, specification, and differentiation decisions in both developmental and adult stem cell populations are or are not regulated by the classical TTFL; and emerging evidence that we propose implies a primordial clock that precedes the classical TTFL and influences early developmental decisions.
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Affiliation(s)
- Joseph Lewis Bedont
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Daniel Maxim Iascone
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Amita Sehgal
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
- The Howard Hughes Medical Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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12
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Core-clock genes Period 1 and 2 regulate visual cascade and cell cycle components during mouse eye development. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194623. [PMID: 32795630 DOI: 10.1016/j.bbagrm.2020.194623] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 08/07/2020] [Accepted: 08/07/2020] [Indexed: 12/16/2022]
Abstract
The retinas from Period 1 (Per1) and Period 2 (Per2) double-mutant mice (Per1-/-Per2Brdm1) display abnormal blue-cone distribution associated with a reduction in cone opsin mRNA and protein levels, up to 1 year of age. To reveal the molecular mechanisms by which Per1 and Per2 control retina development, we analyzed genome-wide gene expression differences between wild-type (WT) and Per1-/-Per2Brdm1 mice across ocular developmental stages (E15, E18 and P3). All clock genes displayed changes in transcript levels along with normal eye development. RNA-Seq data show major gene expression changes between WT and mutant eyes, with the number of differentially expressed genes (DEG) increasing with developmental age. Functional annotation of the genes showed that the most significant changes in expression levels in mutant mice involve molecular pathways relating to circadian rhythm signaling at E15 and E18. At P3, the visual cascade and the cell cycle were respectively higher and lower expressed compared to WT eyes. Overall, our study provides new insights into signaling pathways -phototransduction and cell cycle- controlled by the circadian clock in the eye during development.
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13
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Shakhmantsir I, Dooley SJ, Kishore S, Chen D, Pierce E, Bennett J, Sehgal A. RNA Splicing Factor Mutations That Cause Retinitis Pigmentosa Result in Circadian Dysregulation. J Biol Rhythms 2019; 35:72-83. [PMID: 31726916 DOI: 10.1177/0748730419887876] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Circadian clocks regulate multiple physiological processes in the eye, but their requirement for retinal health remains unclear. We previously showed that Drosophila homologs of spliceosome proteins implicated in human retinitis pigmentosa (RP), the most common genetically inherited cause of blindness, have a role in the brain circadian clock. In this study, we report circadian phenotypes in murine models of RP. We found that mice carrying a homozygous H2309P mutation in Pre-mRNA splicing factor 8 (Prpf8) display a lengthened period of the circadian wheel-running activity rhythm. We show also that the daily cycling of circadian gene expression is dampened in the retina of Prpf8-H2309P mice. Surprisingly, molecular rhythms are intact in the eye cup, which includes the retinal pigment epithelium (RPE), even though the RPE is thought to be the primary tissue affected in this form of RP. Downregulation of Prp31, another RNA splicing factor implicated in RP, leads to period lengthening in a human cell culture model. The period of circadian bioluminescence in primary fibroblasts of human RP patients is not significantly altered. Together, these studies link a prominent retinal disorder to circadian deficits, which could contribute to disease pathology.
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Affiliation(s)
- Iryna Shakhmantsir
- Chronobiology and Sleep institute (CSI) and Howard Hughes Medical Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Graduate Program in Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Scott J Dooley
- Graduate Program in Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Advanced Retinal and Ocular Therapeutics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Siddharth Kishore
- Graduate Program in Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dechun Chen
- Chronobiology and Sleep institute (CSI) and Howard Hughes Medical Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eric Pierce
- Ocular Genomics Institute, Mass Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Amita Sehgal
- Chronobiology and Sleep institute (CSI) and Howard Hughes Medical Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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14
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Sawant OB, Jidigam VK, Fuller RD, Zucaro OF, Kpegba C, Yu M, Peachey NS, Rao S. The circadian clock gene Bmal1 is required to control the timing of retinal neurogenesis and lamination of Müller glia in the mouse retina. FASEB J 2019; 33:8745-8758. [PMID: 31002540 PMCID: PMC6662963 DOI: 10.1096/fj.201801832rr] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 04/02/2019] [Indexed: 12/20/2022]
Abstract
A single pool of multipotent retinal progenitor cells give rise to the diverse cell types within the mammalian retina. Such cellular diversity is due to precise control of various cellular processes like cell specification, proliferation, differentiation, and maturation. Circadian clock genes can control the expression of key regulators of cell cycle progression and therefore can synchronize the cell cycle state of a heterogeneous population of cells. Here we show that the protein encoded by the circadian clock gene brain and muscle arnt-like protein-1 (Bmal1) is expressed in the embryonic retina and is required to regulate the timing of cell cycle exit. Accordingly, loss of Bmal1 during retinal neurogenesis results in increased S-phase entry and delayed cell cycle exit. Disruption in cell cycle kinetics affects the timely generation of the appropriate neuronal population thus leading to an overall decrease in the number of retinal ganglion cells, amacrine cells, and an increase in the number of the late-born type II cone bipolar cells as well as the Müller glia. Additionally, the mislocalized Müller cells are observed in the photoreceptor layer in the Bmal1 conditional mutants. These changes affect the functional integrity of the visual circuitry as we report a significant delay in visual evoked potential implicit time in the retina-specific Bmal1 null animals. Our results demonstrate that Bmal1 is required to maintain the balance between the neural and glial cells in the embryonic retina by coordinating the timing of cell cycle entry and exit. Thus, Bmal1 plays an essential role during retinal neurogenesis affecting both development and function of the mature retina.-Sawant, O. B., Jidigam, V. K., Fuller, R. D., Zucaro, O. F., Kpegba, C., Yu, M., Peachey, N. S., Rao, S. The circadian clock gene Bmal1 is required to control the timing of retinal neurogenesis and lamination of Müller glia in the mouse retina.
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Affiliation(s)
- Onkar B. Sawant
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Vijay K. Jidigam
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Rebecca D. Fuller
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Olivia F. Zucaro
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Cristel Kpegba
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Sujata Rao
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
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Felder-Schmittbuhl MP, Buhr ED, Dkhissi-Benyahya O, Hicks D, Peirson SN, Ribelayga CP, Sandu C, Spessert R, Tosini G. Ocular Clocks: Adapting Mechanisms for Eye Functions and Health. Invest Ophthalmol Vis Sci 2019; 59:4856-4870. [PMID: 30347082 PMCID: PMC6181243 DOI: 10.1167/iovs.18-24957] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Vision is a highly rhythmic function adapted to the extensive changes in light intensity occurring over the 24-hour day. This adaptation relies on rhythms in cellular and molecular processes, which are orchestrated by a network of circadian clocks located within the retina and in the eye, synchronized to the day/night cycle and which, together, fine-tune detection and processing of light information over the 24-hour period and ensure retinal homeostasis. Systematic or high throughput studies revealed a series of genes rhythmically expressed in the retina, pointing at specific functions or pathways under circadian control. Conversely, knockout studies demonstrated that the circadian clock regulates retinal processing of light information. In addition, recent data revealed that it also plays a role in development as well as in aging of the retina. Regarding synchronization by the light/dark cycle, the retina displays the unique property of bringing together light sensitivity, clock machinery, and a wide range of rhythmic outputs. Melatonin and dopamine play a particular role in this system, being both outputs and inputs for clocks. The retinal cellular complexity suggests that mechanisms of regulation by light are diverse and intricate. In the context of the whole eye, the retina looks like a major determinant of phase resetting for other tissues such as the retinal pigmented epithelium or cornea. Understanding the pathways linking the cell-specific molecular machineries to their cognate outputs will be one of the major challenges for the future.
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Affiliation(s)
- Marie-Paule Felder-Schmittbuhl
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Ethan D Buhr
- Department of Ophthalmology, University of Washington Medical School, Seattle, Washington, United States
| | - Ouria Dkhissi-Benyahya
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - David Hicks
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Christophe P Ribelayga
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States
| | - Cristina Sandu
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology & Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States
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16
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Vancura P, Csicsely E, Leiser A, Iuvone PM, Spessert R. Rhythmic Regulation of Photoreceptor and RPE Genes Important for Vision and Genetically Associated With Severe Retinal Diseases. Invest Ophthalmol Vis Sci 2019; 59:3789-3799. [PMID: 30073352 PMCID: PMC6071477 DOI: 10.1167/iovs.18-24558] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The aim of the present study was to identify candidate genes for mediating daily adjustment of vision. Methods Genes important for vision and genetically associated with severe retinal diseases were tested for 24-hour rhythms in transcript levels in neuronal retina, microdissected photoreceptors, photoreceptor-related pinealocytes, and retinal pigment epithelium-choroid (RPE-choroid) complex by using quantitative PCR. Results Photoreceptors of wildtype mice display circadian clock-dependent regulation of visual arrestins (Arr1, Arr4) and the visual cycle gene Rdh12, whereas cells of the RPE-choroid exhibit light-dependent regulation of the visual cycle key genes Lrat, Rpe65, and Rdh5. Clock-driven rhythmicity of Arr1, Arr4, and Rdh12 was observed also in rat pinealocytes, to persist in a mouse model of diabetic retinopathy (db/db) and, in the case of Arr1, to be abolished in retinae of mice deficient for dopamine D4 receptors. Therefore, the expression rhythms appear to be evolutionary conserved, to be unaffected in diabetic retinopathy, and, for Arr1, to require dopamine signaling via dopamine D4 receptors. Conclusions The data of the present study suggest that daily adjustment of retinal function combines clock-dependent regulation of genes responsible for phototransduction termination (Arr1, Arr4) and detoxification (Rdh12) in photoreceptors with light-dependent regulation of genes responsible for retinoid recycling (Lrat, Rpe65, and Rdh5) in RPE. Furthermore, they indicate circadian and light-dependent regulation of genes genetically associated with severe retinal diseases.
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Affiliation(s)
- Patrick Vancura
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Erika Csicsely
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Annalisa Leiser
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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17
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Ko GYP. Circadian regulation in the retina: From molecules to network. Eur J Neurosci 2018; 51:194-216. [PMID: 30270466 DOI: 10.1111/ejn.14185] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/16/2018] [Accepted: 08/20/2018] [Indexed: 12/14/2022]
Abstract
The mammalian retina is the most unique tissue among those that display robust circadian/diurnal oscillations. The retina is not only a light sensing tissue that relays light information to the brain, it has its own circadian "system" independent from any influence from other circadian oscillators. While all retinal cells and retinal pigment epithelium (RPE) possess circadian oscillators, these oscillators integrate by means of neural synapses, electrical coupling (gap junctions), and released neurochemicals (such as dopamine, melatonin, adenosine, and ATP), so the whole retina functions as an integrated circadian system. Dysregulation of retinal clocks not only causes retinal or ocular diseases, it also impacts the circadian rhythm of the whole body, as the light information transmitted from the retina entrains the brain clock that governs the body circadian rhythms. In this review, how circadian oscillations in various retinal cells are integrated, and how retinal diseases affect daily rhythms.
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Affiliation(s)
- Gladys Y-P Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas.,Texas A&M Institute for Neuroscience, Texas A&M University, College Station, Texas
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18
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Huang DF, Wang MY, Yin W, Ma YQ, Wang H, Xue T, Ren DL, Hu B. Zebrafish Lacking Circadian Gene per2 Exhibit Visual Function Deficiency. Front Behav Neurosci 2018; 12:53. [PMID: 29593513 PMCID: PMC5859089 DOI: 10.3389/fnbeh.2018.00053] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/01/2018] [Indexed: 01/09/2023] Open
Abstract
The retina has an intrinsic circadian clock, but the importance of this clock for vision is unknown. Zebrafish offer many advantages for studying vertebrate vision and circadian rhythm. Here, we explored the role of zebrafish per2, a light-regulated gene, in visual behavior and the underlying mechanisms. We observed that per2 mutant zebrafish larvae showed decreased contrast sensitivity and visual acuity using optokinetic response (OKR) assays. Using a visual motor response (VMR) assay, we observed normal OFF responses but abnormal ON responses in mutant zebrafish larvae. Immunofluorescence showed that mutants had a normal morphology of cone photoreceptor cells and retinal organization. However, electron microscopy showed that per2 mutants displayed abnormal and decreased photoreceptor ribbon synapses with arciform density, which resulted in retinal ON pathway defect. We also examined the expression of three cone opsins by quantitative real-time PCR (qRT-PCR), and the expression of long-wave-sensitive opsin (opn1lw) and short-wave-sensitive opsin (opn1sw) was reduced in mutant zebrafish larvae. qRT-PCR analyses also showed a down-regulation of the clock genes cry1ba and bmal1b in the adult eye of per2 mutant zebrafish. This study identified a mechanism by which a clock gene affects visual function and defined important roles of per2 in retinal information processing.
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Affiliation(s)
- Deng-Feng Huang
- Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Brain Function & Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ming-Yong Wang
- School of Biology & Basic Medical Sciences, Medical College, Soochow University, Suzhou, China
| | - Wu Yin
- Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Brain Function & Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yu-Qian Ma
- Neurodegenerative Disorder Research Center, University of Science and Technology of China, Hefei, China
| | - Han Wang
- School of Biology & Basic Medical Sciences, Medical College, Soochow University, Suzhou, China
| | - Tian Xue
- Neurodegenerative Disorder Research Center, University of Science and Technology of China, Hefei, China
| | - Da-Long Ren
- Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Brain Function & Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Bing Hu
- Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Brain Function & Disease, School of Life Sciences, University of Science and Technology of China, Hefei, China
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19
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Baba K, Ribelayga CP, Michael Iuvone P, Tosini G. The Retinal Circadian Clock and Photoreceptor Viability. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1074:345-350. [PMID: 29721962 PMCID: PMC6003627 DOI: 10.1007/978-3-319-75402-4_42] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Circadian rhythms are present in most living organisms, and these rhythms are not just a consequence of the day/night fluctuation, but rather they are generated by endogenous biological clocks with a periodicity of about 24 h. In mammals, the master pacemaker of circadian rhythms is localized in the suprachiasmatic nuclei (SCN) of the hypothalamus. The SCN controls circadian rhythms in peripheral organs. The retina also contains circadian clocks which regulate many aspects of retinal physiology, independently of the SCN. Emerging experimental evidence indicates that the retinal circadian clocks also affect ocular health, and a few studies have now demonstrated that disruption of retinal clocks may contribute to the development of retinal diseases. Our study indicates that in mice lacking the clock gene Bmal1, photoreceptor viability during aging is significantly reduced. Bmal1 knockout mice at 8-9 months of age have 20-30% less nuclei in the outer nuclear layer. No differences were observed in the other retinal layers. Our study suggests that the retinal circadian clock is an important modulator of photoreceptor health.
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Affiliation(s)
- Kenkichi Baba
- Department of Pharmacology and Toxicology Morehouse School of Medicine, Neuroscience Institute, Atlanta, GA, USA.
| | - Christophe P Ribelayga
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - P Michael Iuvone
- Departments of Ophthalmology and Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gianluca Tosini
- Department of Pharmacology and Toxicology Morehouse School of Medicine, Neuroscience Institute, Atlanta, GA, USA
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20
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Sawant OB, Horton AM, Zucaro OF, Chan R, Bonilha VL, Samuels IS, Rao S. The Circadian Clock Gene Bmal1 Controls Thyroid Hormone-Mediated Spectral Identity and Cone Photoreceptor Function. Cell Rep 2017; 21:692-706. [PMID: 29045837 PMCID: PMC5647869 DOI: 10.1016/j.celrep.2017.09.069] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/15/2017] [Accepted: 09/20/2017] [Indexed: 10/18/2022] Open
Abstract
Circadian clocks regulate various aspects of photoreceptor physiology, but their contribution to photoreceptor development and function is unclear. Cone photoreceptors are critical for color vision. Here, we define the molecular function of circadian activity within cone photoreceptors and reveal a role for the clock genes Bmal1 and Per2 in regulating cone spectral identity. ChIP analysis revealed that BMAL1 binds to the promoter region of the thyroid hormone (TH)-activating enzyme type 2 iodothyronine deiodinase (Dio2) and thus regulates the expression of Dio2. TH treatment resulted in a partial rescue of the phenotype caused by the loss of Bmal1, thus revealing a functional relationship between Bmal1 and Dio2 in establishing cone photoreceptor identity. Furthermore, Bmal1 and Dio2 are required to maintain cone photoreceptor functional integrity. Overall, our results suggest a mechanism by which circadian proteins can locally regulate the availability of TH and influence tissue development and function.
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Affiliation(s)
- Onkar B Sawant
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Amanda M Horton
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Olivia F Zucaro
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Ricky Chan
- Institute for Computational Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Vera L Bonilha
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Ivy S Samuels
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Sujata Rao
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
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21
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Dopamine 2 Receptor Activation Entrains Circadian Clocks in Mouse Retinal Pigment Epithelium. Sci Rep 2017; 7:5103. [PMID: 28698578 PMCID: PMC5505969 DOI: 10.1038/s41598-017-05394-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 05/24/2017] [Indexed: 01/11/2023] Open
Abstract
Many of the physiological, cellular, and molecular rhythms that are present within the eye are under the control of circadian clocks. Experimental evidence suggests that the retinal circadian clock, or its output signals (e.g., dopamine and melatonin), may contribute to eye disease and pathology. We recently developed a retinal pigment ephithelium (RPE)-choroid preparation to monitor the circadian clock using PERIOD2 (PER2)::LUC knock-in mouse. In this study we report that dopamine, but not melatonin, is responsible for entrainment of the PER2::LUC bioluminescence rhythm in mouse RPE-choroid. Dopamine induced phase-advances of the PER2::LUC bioluminescence rhythm during the subjective day and phase-delays in the late subjective night. We found that dopamine acts exclusively through Dopamine 2 Receptors to entrain the circadian rhythm in PER2::LUC bioluminescence. Finallly, we found that DA-induced expression of core circadian clock genes Period1 and Period2 accompanied both phase advances and phase delays of the RPE-choroid clock, thus suggesting that - as in other tissues - the rapid induction of these circadian clock genes drives the resetting process. Since the RPE cells persist for the entire lifespan of an organism, we believe that RPE-choroid preparation may represent a new and unique tool to study the effects of circadian disruption during aging.
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22
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Wyse-Jackson AC, Roche SL, Ruiz-Lopez AM, Moloney JN, Byrne AM, Cotter TG. Progesterone analogue protects stressed photoreceptors via bFGF-mediated calcium influx. Eur J Neurosci 2016; 44:3067-3079. [PMID: 27763693 DOI: 10.1111/ejn.13445] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 10/14/2016] [Accepted: 10/17/2016] [Indexed: 01/16/2023]
Abstract
Retinitis pigmentosa (RP) is a degenerative retinal disease leading to photoreceptor cell loss. In 2011, our group identified the synthetic progesterone 'Norgestrel' as a potential treatment for RP. Subsequent research showed Norgestrel to work through progesterone receptor membrane component 1 (PGRMC1) activation and upregulation of neuroprotective basic fibroblast growth factor (bFGF). Using trophic factor deprivation of 661W photoreceptor-like cells, we aimed to further elucidate the mechanism leading to Norgestrel-induced neuroprotection. In the present manuscript, we show by flow cytometry and live-cell immunofluorescence that Norgestrel induces an increase in cytosolic calcium in both healthy and stressed 661Ws over 24 h. Specific PGRMC1 inhibition by AG205 (1 μm) showed this rise to be PGRMC1-dependent, primarily utilizing calcium from extracellular sources, for blockade of L-type calcium channels by verapamil (50 μm) prevented a Norgestrel-induced calcium influx in stressed cells. Calcium influx was also shown to be bFGF-dependent, for siRNA knock down of bFGF prevented Norgestrel-PGRMC1 induced changes in cytosolic calcium. Notably, we demonstrate PGRMC1-activation is necessary for Norgestrel-induced bFGF upregulation. We propose that Norgestrel protects through the following pathway: binding to and activating PGRMC1 expressed on the surface of photoreceptor cells, PGRMC1 activation drives bFGF upregulation and subsequent calcium influx. Importantly, raised intracellular calcium is critical to Norgestrel's protective efficacy, for extracellular calcium chelation by EGTA abrogates the protective effects of Norgestrel on stressed 661W cells in vitro.
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Affiliation(s)
- Alice C Wyse-Jackson
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Western Road, Cork, Ireland
| | - Sarah L Roche
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Western Road, Cork, Ireland
| | - Ana M Ruiz-Lopez
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Western Road, Cork, Ireland
| | - Jennifer N Moloney
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Western Road, Cork, Ireland
| | - Ashleigh M Byrne
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Western Road, Cork, Ireland
| | - Thomas G Cotter
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Western Road, Cork, Ireland
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23
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Jadhav V, Luo Q, M. Dominguez J, Al-Sabah J, Chaqour B, Grant MB, Bhatwadekar AD. Per2-Mediated Vascular Dysfunction Is Caused by the Upregulation of the Connective Tissue Growth Factor (CTGF). PLoS One 2016; 11:e0163367. [PMID: 27662578 PMCID: PMC5035004 DOI: 10.1371/journal.pone.0163367] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/07/2016] [Indexed: 01/08/2023] Open
Abstract
Period 2-mutant mice (Per2m/m), which possess a circadian dysfunction, recapitulate the retinal vascular phenotype similar to diabetic retinopathy (DR). The vascular dysfunction in Per2m/m is associated with an increase in connective tissue growth factor (CTGF/CCN2). At the molecular level, CTGF gene expression is dependent on the canonical Wnt/β-catenin pathway. The nuclear binding of β-catenin to a transcription factor, lymphoid enhancer binding protein (Lef)/ T-cell factor (TCF/LEF), leads to downstream activation of CTGF. For this study, we hypothesized that the silencing of Per2 results in nuclear translocation and subsequent transactivation of the CTGF gene. To test this hypothesis, we performed immunofluorescence labeling for CTGF in retinal sections from wild-type (WT) and Per2m/m mice. Human retinal endothelial cells (HRECs) were transfected with siRNA for Per2, and the protein expression of CTGF and β-catenin was evaluated. The TCF/LEF luciferase reporter (TOPflash) assay was performed to validate the involvement of β-catenin in the activation of CTGF. Per2m/m retinas exhibited an increased CTGF immunostaining in ganglion cell layer and retinal endothelium. Silencing of Per2 using siRNA resulted in an upregulation of CTGF and β-catenin. The TOPflash assay revealed an increase in luminescence for HRECs transfected with Per2 siRNA. Our studies show that loss of Per2 results in an activation of CTGF via nuclear entry of β-catenin. Our study provides novel insight into the understanding of microvascular dysfunction in Per2m/m mice.
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Affiliation(s)
- Vaishnavi Jadhav
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Qianyi Luo
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - James M. Dominguez
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Jude Al-Sabah
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Brahim Chaqour
- Department of Cell Biology, Suny Downstate Medical Center, Brooklyn, New York, United States of America
| | - Maria B. Grant
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Ashay D. Bhatwadekar
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail:
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Ait-Hmyed Hakkari O, Acar N, Savier E, Spinnhirny P, Bennis M, Felder-Schmittbuhl MP, Mendoza J, Hicks D. Rev-Erbα modulates retinal visual processing and behavioral responses to light. FASEB J 2016; 30:3690-3701. [PMID: 27440795 DOI: 10.1096/fj.201600414r] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 07/05/2016] [Indexed: 01/16/2023]
Abstract
The circadian clock is thought to adjust retinal sensitivity to ambient light levels, yet the involvement of specific clock genes is poorly understood. We explored the potential role of the nuclear receptor subfamily 1, group D, member 1 (REV-ERBα; or NR1D1) in this respect. In light-evoked behavioral tests, compared with wild-type littermates, Rev-Erbα-/- mice showed enhanced negative masking at low light levels (0.1 lx). Rev-Erbα-/- mouse retinas displayed significantly higher numbers of intrinsically photosensitive retinal ganglion cells (ipRGCs; 62% more compared with wild-type) and more intense melanopsin immunostaining of individual ipRGCs. In agreement with a pivotal role for melanopsin, negative masking at low light intensities was abolished in Rev-Erbα-/- Opn4-/- (melanopsin gene) double-null mice. Rev-Erbα-/- mice showed shortened latencies of both a and b electroretinogram waves, modified scotopic and photopic b-wave and scotopic threshold responses, and increased pupillary constriction, all of which suggested increased light sensitivity. However, wild-type and Rev-Erbα-/- mice displayed no detectable differences by in vivo fundus imaging, retinal histology, or expression of cell type-specific markers for major retinal cell populations. We conclude that REV-ERBα plays a major role in retinal information processing, and we speculate that REV-ERBα and melanopsin set sensitivity levels of the rod-mediated ipRGC pathway to coordinate activity with ambient light.-Ait-Hmyed Hakkari, O., Acar, N., Savier, E., Spinnhirny, P., Bennis, M., Felder-Schmittbuhl, M.-P., Mendoza, J., Hicks, D. Rev-Erbα modulates retinal visual processing and behavioral responses to light.
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Affiliation(s)
- Ouafa Ait-Hmyed Hakkari
- Department of Neurobiology of Rhythms, Centre National de la Recherche Scientifique, Unités Propres de Recherche 3212, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France.,Université Cadi Ayad, Département de Biologie, Laboratoire de Pharmacologie, Neurobiologie et Comportement, Marrakech, Morocco
| | - Niyazi Acar
- Centre National de la Recherche Scientifique, Unités Mixtes de Recherche 6265, Centre des Sciences du Goût et de l'Alimentation, Dijon, France.,Institut National de la Recherche Agronomique, Unités Mixtes de Recherche 324, Centre des Sciences du Goût et de l'Alimentation, Dijon, France.,Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, Dijon, France
| | - Elise Savier
- Department of Neurobiology of Rhythms, Centre National de la Recherche Scientifique, Unités Propres de Recherche 3212, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Perrine Spinnhirny
- Department of Neurobiology of Rhythms, Centre National de la Recherche Scientifique, Unités Propres de Recherche 3212, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Mohammed Bennis
- Université Cadi Ayad, Département de Biologie, Laboratoire de Pharmacologie, Neurobiologie et Comportement, Marrakech, Morocco
| | - Marie-Paule Felder-Schmittbuhl
- Department of Neurobiology of Rhythms, Centre National de la Recherche Scientifique, Unités Propres de Recherche 3212, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Jorge Mendoza
- Department of Neurobiology of Rhythms, Centre National de la Recherche Scientifique, Unités Propres de Recherche 3212, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - David Hicks
- Department of Neurobiology of Rhythms, Centre National de la Recherche Scientifique, Unités Propres de Recherche 3212, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France;
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25
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Gianesini C, Hiragaki S, Laurent V, Hicks D, Tosini G. Cone Viability Is Affected by Disruption of Melatonin Receptors Signaling. Invest Ophthalmol Vis Sci 2016; 57:94-104. [PMID: 26780313 PMCID: PMC4727519 DOI: 10.1167/iovs.15-18235] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose Previous studies have demonstrated that melatonin has an important role in the modulation of photoreceptor viability during aging and may be involved in the pathogenesis of age-related macular degeneration.This hormone exerts its influence by binding to G-protein coupled receptors named melatonin receptor 1 (MT1) and 2 (MT2). Melatonin receptors 1 and 2 activate a wide variety of signaling pathways. Methods Melatonin-proficient mice (C3H/f+/+) and melatonin-proficient mice lacking MT1 or MT2 receptors (MT1−/− and MT2−/−) were used in this study. Mice were killed at the ages of 3 and 18 months, and photoreceptor viability was determined by counting nuclei number in the outer nuclear layer (ONL). Cones were identified by immunohistochemistry using peanut agglutinin (PNA) and green/red and blue opsin antibodies. Protein kinase B (AKT) and forkhead box O (FOXO1) were assessed by Western blotting and immunohistochemistry. Results The number of nuclei in the ONL was significantly reduced in C3Hf+/+, MT1−/−, and MT2−/− mice at 18 months of age with respect to 3-month-old animals. In 18-month-old MT1−/− and MT2−/− mice, but not in C3H/f+/+, the number of cones was significantly reduced with respect to young MT1−/− and MT2−/− mice or age-matched C3H/f+/+. In C3H/f+/+, activation of the AKT-FOXO1 pathway in the photoreceptors showed a significant difference between night and day. Conclusions Our data indicate that disruption of MT1/MT2 heteromer signaling induces a reduction in the number of photoreceptors during aging and also suggest that the AKT-FOXO1 survival pathway may be involved in the mechanism by which melatonin protects photoreceptors.
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Affiliation(s)
- Coralie Gianesini
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States 2Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neuro
| | - Susumu Hiragaki
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Virginie Laurent
- Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neurosciences, Strasbourg, France
| | - David Hicks
- Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neurosciences, Strasbourg, France
| | - Gianluca Tosini
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States
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Abstract
Ocular clocks, first identified in the retina, are also found in the retinal pigment epithelium (RPE), cornea, and ciliary body. The retina is a complex tissue of many cell types and considerable effort has gone into determining which cell types exhibit clock properties. Current data suggest that photoreceptors as well as inner retinal neurons exhibit clock properties with photoreceptors dominating in nonmammalian vertebrates and inner retinal neurons dominating in mice. However, these differences may in part reflect the choice of circadian output, and it is likely that clock properties are widely dispersed among many retinal cell types. The phase of the retinal clock can be set directly by light. In nonmammalian vertebrates, direct light sensitivity is commonplace among body clocks, but in mice only the retina and cornea retain direct light-dependent phase regulation. This distinguishes the retina and possibly other ocular clocks from peripheral oscillators whose phase depends on the pace-making properties of the hypothalamic central brain clock, the suprachiasmatic nuclei (SCN). However, in mice, retinal circadian oscillations dampen quickly in isolation due to weak coupling of its individual cell-autonomous oscillators, and there is no evidence that retinal clocks are directly controlled through input from other oscillators. Retinal circadian regulation in both mammals and nonmammalian vertebrates uses melatonin and dopamine as dark- and light-adaptive neuromodulators, respectively, and light can regulate circadian phase indirectly through dopamine signaling. The melatonin/dopamine system appears to have evolved among nonmammalian vertebrates and retained with modification in mammals. Circadian clocks in the eye are critical for optimum visual function where they play a role fine tuning visual sensitivity, and their disruption can affect diseases such as glaucoma or retinal degeneration syndromes.
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Affiliation(s)
- Joseph C Besharse
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI
| | - Douglas G McMahon
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
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27
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Wyse Jackson AC, Cotter TG. The synthetic progesterone Norgestrel is neuroprotective in stressed photoreceptor-like cells and retinal explants, mediating its effects via basic fibroblast growth factor, protein kinase A and glycogen synthase kinase 3β signalling. Eur J Neurosci 2016; 43:899-911. [PMID: 26750157 DOI: 10.1111/ejn.13166] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 12/17/2015] [Accepted: 12/29/2015] [Indexed: 01/19/2023]
Abstract
The synthetic progesterone Norgestrel has been shown to have proven neuroprotective efficacy in two distinct models of retinitis pigmentosa: the rd10/rd10 (B6.CXBI-Pde6b(rd10)/J) mouse model and the Balb/c light-damage model. However, the cellular mechanism underlying this neuroprotection is still largely unknown. Therefore, this study aimed to examine the downstream signalling pathways associated with Norgestrel both in vitro and ex vivo. In this work, we identify the potential of Norgestrel to rescue stressed 661W photoreceptor-like cells and ex vivo retinal explants from cell death over 24 h. Norgestel is thought to work through an upregulation of neuroprotective basic fibroblast growth factor (bFGF). Analysis of 661W cells in vitro by real-time polymerase chain reaction (rt-PCR), enzyme-linked immunosorbent assay (ELISA) and Western blotting revealed an upregulation of bFGF in response to Norgestrel over 6 h. Specific siRNA knockdown of bFGF abrogated the protective properties of Norgestrel on damaged photoreceptors, thus highlighting the crucial importance of bFGF in Norgestrel-mediated protection. Furthermore, Norgestrel initiated a bFGF-dependent inactivation of glycogen synthase kinase 3β (GSK3β) through phosphorylation at serine 9. The effects of Norgestrel on GSK3β were dependent on protein kinase A (PKA) pathway activation. Specific inhibition of both the PKA and GSK3β pathways prevented Norgestrel-mediated neuroprotection of stressed photoreceptor cells in vitro. Involvement of the PKA pathway following Norgestrel treatment was also confirmed ex vivo. Therefore, these results indicate that the protective efficacy of Norgestrel is, at least in part, due to the bFGF-mediated activation of the PKA pathway, with subsequent inactivation of GSK3β.
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Affiliation(s)
- Alice C Wyse Jackson
- Biochemistry Department, Cell Development and Disease Laboratory, Bioscience Research Institute, University College Cork, College Road, Cork City Centre, Cork, Ireland
| | - Thomas G Cotter
- Biochemistry Department, Cell Development and Disease Laboratory, Bioscience Research Institute, University College Cork, College Road, Cork City Centre, Cork, Ireland
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28
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Kunst S, Wolloscheck T, Kelleher DK, Wolfrum U, Sargsyan SA, Iuvone PM, Baba K, Tosini G, Spessert R. Pgc-1α and Nr4a1 Are Target Genes of Circadian Melatonin and Dopamine Release in Murine Retina. Invest Ophthalmol Vis Sci 2016; 56:6084-94. [PMID: 26393668 DOI: 10.1167/iovs.15-17503] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE The neurohormones melatonin and dopamine mediate clock-dependent/circadian regulation of inner retinal neurons and photoreceptor cells and in this way promote their functional adaptation to time of day and their survival. To fulfill this function they act on melatonin receptor type 1 (MT1 receptors) and dopamine D4 receptors (D4 receptors), respectively. The aim of the present study was to screen transcriptional regulators important for retinal physiology and/or pathology (Dbp, Egr-1, Fos, Nr1d1, Nr2e3, Nr4a1, Pgc-1α, Rorβ) for circadian regulation and dependence on melatonin signaling/MT1 receptors or dopamine signaling/D4 receptors. METHODS This was done by gene profiling using quantitative polymerase chain reaction in mice deficient in MT1 or D4 receptors. RESULTS The data obtained determined Pgc-1α and Nr4a1 as transcriptional targets of circadian melatonin and dopamine signaling, respectively. CONCLUSIONS The results suggest that Pgc-1α and Nr4a1 represent candidate genes for linking circadian neurohormone release with functional adaptation and healthiness of retina and photoreceptor cells.
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Affiliation(s)
- Stefanie Kunst
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany 2Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University, Mainz, Germany
| | - Tanja Wolloscheck
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Debra K Kelleher
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Uwe Wolfrum
- Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University, Mainz, Germany
| | - S Anna Sargsyan
- Departments of Ophthalmology and Pharmacology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - P Michael Iuvone
- Departments of Ophthalmology and Pharmacology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Kenkichi Baba
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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29
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Jackson ACW, Roche SL, Byrne AM, Ruiz-Lopez AM, Cotter TG. Progesterone receptor signalling in retinal photoreceptor neuroprotection. J Neurochem 2015; 136:63-77. [PMID: 26447367 DOI: 10.1111/jnc.13388] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 09/29/2015] [Accepted: 10/02/2015] [Indexed: 11/29/2022]
Abstract
'Norgestrel', a synthetic form of the female hormone progesterone has been identified as potential drug candidate for the treatment of the degenerative eye disease retinitis pigmentosa. However, to date, no work has looked at the compound's specific cellular target. Therefore, this study aimed to identify the receptor target of Norgestrel and begin to examine its potential mechanism of action in the retina. In this work, we identify and characterize the expression of progesterone receptors present in the C57 wild type and rd10 mouse model of retinitis pigmentosa. Classical progesterone receptors A and B (PR A/B), progesterone receptor membrane components 1 and 2 (PGRMC1, PGRMC2) and membrane progesterone receptors α, β and γ were found to be expressed. All receptors excluding PR A/B were also found in the 661W photoreceptor cell line. PGRMC1 is a key regulator of apoptosis and its expression is up-regulated in the degenerating rd10 mouse retina. Activated by Norgestrel through nuclear trafficking, siRNA knock down of PGRMC1 abrogated the protective properties of Norgestrel on damaged photoreceptors. Furthermore, specific inhibition of PGRMC1 by AG205 blocked Norgestrel-induced protection in stressed retinal explants. Therefore, we conclude that PGRMC1 is crucial to the neuroprotective effects of Norgestrel on stressed photoreceptors. The synthetic progestin 'Norgestrel' has been identified as a potential therapeutic for the treatment of Retinitis Pigmentosa, a degenerative eye disease. However, the mechanism behind this neuroprotection is currently unknown. In this work, we identify 'Progesterone Receptor Membrane Component 1' as the major progesterone receptor eliciting the protective effects of Norgestrel, both in vitro and ex vivo. This furthers our understanding of Norgestrel's molecular mechanism, which we hope will help bring Norgestrel one step closer to the clinic.
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Affiliation(s)
- Alice C Wyse Jackson
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
| | - Sarah L Roche
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
| | - Ashleigh M Byrne
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
| | - Ana M Ruiz-Lopez
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
| | - Thomas G Cotter
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
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30
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McMahon DG, Iuvone PM, Tosini G. Circadian organization of the mammalian retina: from gene regulation to physiology and diseases. Prog Retin Eye Res 2013; 39:58-76. [PMID: 24333669 DOI: 10.1016/j.preteyeres.2013.12.001] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/27/2013] [Accepted: 12/01/2013] [Indexed: 01/27/2023]
Abstract
The retinal circadian system represents a unique structure. It contains a complete circadian system and thus the retina represents an ideal model to study fundamental questions of how neural circadian systems are organized and what signaling pathways are used to maintain synchrony of the different structures in the system. In addition, several studies have shown that multiple sites within the retina are capable of generating circadian oscillations. The strength of circadian clock gene expression and the emphasis of rhythmic expression are divergent across vertebrate retinas, with photoreceptors as the primary locus of rhythm generation in amphibians, while in mammals clock activity is most robust in the inner nuclear layer. Melatonin and dopamine serve as signaling molecules to entrain circadian rhythms in the retina and also in other ocular structures. Recent studies have also suggested GABA as an important component of the system that regulates retinal circadian rhythms. These transmitter-driven influences on clock molecules apparently reinforce the autonomous transcription-translation cycling of clock genes. The molecular organization of the retinal clock is similar to what has been reported for the SCN although inter-neural communication among retinal neurons that form the circadian network is apparently weaker than those present in the SCN, and it is more sensitive to genetic disruption than the central brain clock. The melatonin-dopamine system is the signaling pathway that allows the retinal circadian clock to reconfigure retinal circuits to enhance light-adapted cone-mediated visual function during the day and dark-adapted rod-mediated visual signaling at night. Additionally, the retinal circadian clock also controls circadian rhythms in disk shedding and phagocytosis, and possibly intraocular pressure. Emerging experimental data also indicate that circadian clock is also implicated in the pathogenesis of eye disease and compelling experimental data indicate that dysfunction of the retinal circadian system negatively impacts the retina and possibly the cornea and the lens.
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Affiliation(s)
- Douglas G McMahon
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA; Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, 30310 GA, USA.
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