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Stofkova A, Zloh M, Andreanska D, Fiserova I, Kubovciak J, Hejda J, Kutilek P, Murakami M. Depletion of Retinal Dopaminergic Activity in a Mouse Model of Rod Dysfunction Exacerbates Experimental Autoimmune Uveoretinitis: A Role for the Gateway Reflex. Int J Mol Sci 2021; 23:ijms23010453. [PMID: 35008877 PMCID: PMC8745287 DOI: 10.3390/ijms23010453] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/24/2021] [Accepted: 12/29/2021] [Indexed: 12/20/2022] Open
Abstract
The gateway reflex is a mechanism by which neural inputs regulate chemokine expression at endothelial cell barriers, thereby establishing gateways for the invasion of autoreactive T cells into barrier-protected tissues. In this study, we hypothesized that rod photoreceptor dysfunction causes remodeling of retinal neural activity, which influences the blood–retinal barrier and the development of retinal inflammation. We evaluated this hypothesis using Gnat1rd17 mice, a model of night blindness with late-onset rod-cone dystrophy, and experimental autoimmune uveoretinitis (EAU). Retinal remodeling and its effect on EAU development were investigated by transcriptome profiling, target identification, and functional validation. We showed that Gnat1rd17 mice primarily underwent alterations in their retinal dopaminergic system, triggering the development of an exacerbated EAU, which was counteracted by dopamine replacement with L-DOPA administered either systemically or locally. Remarkably, dopamine acted on retinal endothelial cells to inhibit NF-κB and STAT3 activity and the expression of downstream target genes such as chemokines involved in T cell recruitment. These results suggest that rod-mediated dopamine release functions in a gateway reflex manner in the homeostatic control of immune cell entry into the retina, and the loss of retinal dopaminergic activity in conditions associated with rod dysfunction increases the susceptibility to autoimmune uveitis.
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Affiliation(s)
- Andrea Stofkova
- Department of Physiology, Third Faculty of Medicine, Charles University, Ke Karlovu 4, 120 00 Prague, Czech Republic; (M.Z.); (D.A.); (I.F.)
- Correspondence: ; Tel.: +420-224-902-718
| | - Miloslav Zloh
- Department of Physiology, Third Faculty of Medicine, Charles University, Ke Karlovu 4, 120 00 Prague, Czech Republic; (M.Z.); (D.A.); (I.F.)
| | - Dominika Andreanska
- Department of Physiology, Third Faculty of Medicine, Charles University, Ke Karlovu 4, 120 00 Prague, Czech Republic; (M.Z.); (D.A.); (I.F.)
| | - Ivana Fiserova
- Department of Physiology, Third Faculty of Medicine, Charles University, Ke Karlovu 4, 120 00 Prague, Czech Republic; (M.Z.); (D.A.); (I.F.)
- Department of Pathophysiology, Third Faculty of Medicine, Charles University, Ruska 87, 100 00 Prague, Czech Republic
| | - Jan Kubovciak
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic;
| | - Jan Hejda
- Department of Health Care and Population Protection, Faculty of Biomedical Engineering, Czech Technical University in Prague, Sitna Sq. 3105, 272 01 Kladno, Czech Republic; (J.H.); (P.K.)
| | - Patrik Kutilek
- Department of Health Care and Population Protection, Faculty of Biomedical Engineering, Czech Technical University in Prague, Sitna Sq. 3105, 272 01 Kladno, Czech Republic; (J.H.); (P.K.)
| | - Masaaki Murakami
- Division of Molecular Psychoimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo 060-0815, Japan;
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Evidence for a dysfunction and disease-promoting role of the circadian clock in the diabetic retina. Exp Eye Res 2021; 211:108751. [PMID: 34478739 DOI: 10.1016/j.exer.2021.108751] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 08/12/2021] [Accepted: 08/25/2021] [Indexed: 11/21/2022]
Abstract
Diabetic retinopathy is a major complication of chronic hyperglycemia and a leading cause of blindness in developed countries. In the present study the interaction between diabetes and retinal clocks was investigated in mice. It was seen that in the db/db mouse - a widely used animal model of diabetic retinopathy - clock function and circadian regulation of gene expression was disturbed in the retina. Remarkably, elimination of clock function by Bmal1-deficiency mitigates the progression of pathophysiology of the diabetic retina. Thus high-fat diet was seen to induce histopathology and molecular markers associated with diabetic retinopathy in wild type but not in Bmal1-deficient mice. The data of the present study suggest that Bmal1/the retinal clock system is both, a target and an effector of diabetes mellitus in the retina and hence represents a putative therapeutic target in the pathogenesis of diabetic retinopathy.
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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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Beeson C, Peterson YK, Perron N, Bandyopadhyay M, Nasarre C, Beeson G, Comer RF, Lindsey CC, Schnellmann RG, Rohrer B. Newly Identified Chemicals Preserve Mitochondrial Capacity and Decelerate Loss of Photoreceptor Cells in Murine Retinal Degeneration Models. J Ocul Pharmacol Ther 2021; 37:367-378. [PMID: 33945330 DOI: 10.1089/jop.2020.0140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Purpose: Metabolic stress and associated mitochondrial dysfunction are implicated in retinal degeneration irrespective of the underlying cause. We identified seven unique chemicals from a Chembridge DiverSET screen and tested their protection against photoreceptor cell death in cell- and animal-based approaches. Methods: Calcium overload (A23187) was triggered in 661W murine photoreceptor-derived cells, and changes in redox potential and real-time changes in cellular metabolism were assessed using the MTT and Seahorse Biosciences XF assay, respectively. Cheminformatics to compare structures, and biodistribution in the living pig eye aided in selection of the lead compound. In-situ, retinal organ cultures of rd1 mouse and S334ter-line-3 rat were tested, in-vivo the light-induced retinal degeneration in albino Balb/c mice was used, assessing photoreceptor cell numbers histologically. Results: Of the seven chemicals, six were protective against A23187- and IBMX-induced loss of mitochondrial capacity, as measured by viability and respirometry in 661W cells. Cheminformatic analyses identified a unique pharmacophore with 6 physico-chemical features based on two compounds (CB11 and CB12). The protective efficacy of CB11 was further shown by reducing photoreceptor cell loss in retinal explants from two retinitis pigmentosa rodent models. Using eye drops, CB11 targeting to the pig retina was confirmed. The same eye drops decreased photoreceptor cell loss in light-stressed Balb/c mice. Conclusions: New chemicals were identified that protect from mitochondrial damage and lead to improved mitochondrial function. Using ex-vivo and in-vivo models, CB11 decreased the loss of photoreceptor cells in murine models of retinal degeneration and may be effective as treatment for different retinal dystrophies.
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Affiliation(s)
- Craig Beeson
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Yuri K Peterson
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Nathan Perron
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Mausumi Bandyopadhyay
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Cecile Nasarre
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Gyda Beeson
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Richard F Comer
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Christopher C Lindsey
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Rick G Schnellmann
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona, USA.,Research Service, Southern Arizona VA Healthcare System, Tucson, Arizona, USA
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA.,Research Service, Ralph H Johnson VA Medical Center, Charleston, South Carolina, USA
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Alex A, Luo Q, Mathew D, Di R, Bhatwadekar AD. Metformin Corrects Abnormal Circadian Rhythm and Kir4.1 Channels in Diabetes. Invest Ophthalmol Vis Sci 2021; 61:46. [PMID: 32572457 PMCID: PMC7415324 DOI: 10.1167/iovs.61.6.46] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose Diabetic retinopathy (DR) is a leading cause of visual impairment. Müller cells in DR are dysfunctional due to downregulation of the inwardly rectifying potassium channel Kir4.1. Metformin, a commonly used oral antidiabetic drug, is known to elicit its action through 5′ adenosine monophosphate-activated protein kinase (AMPK), a cellular metabolic regulator; however, its effect on Kir4.1 channels is unknown. For this study, we hypothesized that metformin treatment would correct circadian rhythm disruption and Kir4.1 channel dysfunction in db/db mice. Methods Metformin was given orally to db/db mice. Wheel-running activity, retinal levels of Kir4.1, and AMPK phosphorylation were determined at study termination. In parallel, rat retinal Müller cell line (rMC-1) cells were treated using metformin and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) to assess the effect of AMPK activation on the Kir4.1 channel. Results The wheel-running activity of the db/db mice was improved following the metformin treatment. The Kir4.1 level in Müller cells was corrected after metformin treatment. Metformin treatment led to an upregulation of clock regulatory genes such as melanopsin (Opn4) and aralkylamine N-acetyltransferase (Aanat). In rMC-1 cells, AMPK activation via AICAR and metformin resulted in increased Kir4.1 and intermediate core clock component Bmal-1 protein expression. The silencing of Prkaa1 (gene for AMPKα1) led to decreased Kir4.1 and Bmal-1 protein expression. Conclusions Our findings demonstrate that metformin corrects abnormal circadian rhythm and Kir4.1 channels in db/db mouse a model of type 2 diabetes. Metformin could represent a critical pharmacological agent for preventing Müller cell dysfunction observed in human DR.
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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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Stolf AM, Lugarini D, de Oliveira A, Sereniki AP, Santos Capitelli C, Tanaka DH, Ferreira FM, Aparecida Barbato Frazão Vital M, Acco A. Pharmacological study of a cannabinoid-containing eyedrop formulation in dogs and mice. J Appl Biomed 2016. [DOI: 10.1016/j.jab.2015.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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8
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Better Utilization of Mouse Models of Neurodegenerative Diseases in Preclinical Studies: From the Bench to the Clinic. Methods Mol Biol 2016; 1438:311-47. [PMID: 27150098 DOI: 10.1007/978-1-4939-3661-8_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The major symptom of Alzheimer's disease is dementia progressing with age. Its clinical diagnosis is preceded by a long prodromal period of brain pathology that encompasses both formation of extracellular amyloid and intraneuronal tau deposits in the brain and widespread neuronal death. At present, familial cases of dementia provide the most promising foundation for modeling neurodegenerative tauopathies, a group of heterogeneous disorders characterized by prominent intracellular accumulation of hyperphosphorylated tau protein. In this chapter, we describe major behavioral hallmarks of tauopathies, briefly outline the genetics underlying familial cases, and discuss the arising implications for modeling the disease in transgenic mouse systems. The selection of tests performed to evaluate the phenotype of a model should be guided by the key behavioral hallmarks that characterize human disorder and their homology to mouse cognitive systems. We attempt to provide general guidelines and establish criteria for modeling dementia in a mouse; however, interpretations of obtained results should avoid a reductionist "one gene, one disease" explanation of model characteristics. Rather, the focus should be directed to the question of how the mouse genome can cope with the over-expression of the protein coded by transgene(s). While each model is valuable within its own constraints and the experiments performed are guided by specific hypotheses, we seek to expand upon their methodology by offering guidance spanning from issues of mouse husbandry to choices of behavioral tests and routes of drug administration that might increase the external validity of studies and consequently optimize the translational aspect of preclinical research.
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Inhibition of dopamine signaling suppresses cGMP accumulation in rd1 retinal organ cultures. Neuroreport 2015; 25:601-6. [PMID: 24614363 DOI: 10.1097/wnr.0000000000000145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The rd1 mouse is a model of retinitis pigmentosa, an inherited photoreceptor neurodegenerative disease. In rd1 retina, early onset rod degeneration is caused by a Pde6b mutation that leads to high levels of intracellular cyclic guanosine monophosphate (cGMP). Cyclic nucleotide-gated ion channels (CNGCs), necessary for phototransduction, are regulated by cGMP. We have previously demonstrated that inhibition of dopamine signaling blocks rd1 photoreceptor degeneration in retinal organ cultures. The mechanism underlying this protection remains unknown. The aim of this study was to determine whether inhibition of dopamine signaling alters cGMP accumulation or CNGC expression. Dopamine depletion from rd1 retinal organ cultures resulted in a significant decrease in cGMP compared with untreated rd1 organ cultures. However, cGMP levels in both treated and untreated rd1 organ cultures significantly exceeded cGMP levels in wild-type (wt) retinal organ cultures. The CNGC expression profile was first determined in vivo. Both channel subunits, Cnga1 and Cngb1, are expressed at low levels by postnatal day 2 (P2), increasing sharply by P6 with a modest increase after P12 in wt retina. A similar pattern is seen in rd1 retina until P12 when expression levels decrease, leading to cell death. No significant difference was observed in the expression of either Cnga1 or Cngb1 in organ cultures from wt, rd1, and dopamine-depleted rd1 retinas. Our results show that dopamine depletion significantly decreases cGMP levels in rd1 retinal organ cultures, but that cGMP accumulation remains high, requiring additional mechanisms for photoreceptor protection. These mechanisms may include activation of protein kinase G-signaling pathways and/or crosstalk with dopamine signaling through cyclic adenosine monophosphate pathways.
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Bonmati-Carrion MA, Arguelles-Prieto R, Martinez-Madrid MJ, Reiter R, Hardeland R, Rol MA, Madrid JA. Protecting the melatonin rhythm through circadian healthy light exposure. Int J Mol Sci 2014; 15:23448-500. [PMID: 25526564 PMCID: PMC4284776 DOI: 10.3390/ijms151223448] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/02/2014] [Accepted: 11/09/2014] [Indexed: 12/14/2022] Open
Abstract
Currently, in developed countries, nights are excessively illuminated (light at night), whereas daytime is mainly spent indoors, and thus people are exposed to much lower light intensities than under natural conditions. In spite of the positive impact of artificial light, we pay a price for the easy access to light during the night: disorganization of our circadian system or chronodisruption (CD), including perturbations in melatonin rhythm. Epidemiological studies show that CD is associated with an increased incidence of diabetes, obesity, heart disease, cognitive and affective impairment, premature aging and some types of cancer. Knowledge of retinal photoreceptors and the discovery of melanopsin in some ganglion cells demonstrate that light intensity, timing and spectrum must be considered to keep the biological clock properly entrained. Importantly, not all wavelengths of light are equally chronodisrupting. Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night, and induces the strongest melatonin inhibition. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs) and electronic devices. Thus, the development of lighting systems that preserve the melatonin rhythm could reduce the health risks induced by chronodisruption. This review addresses the state of the art regarding the crosstalk between light and the circadian system.
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Affiliation(s)
| | | | | | - Russel Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
| | - Ruediger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen 37073, Germany.
| | - Maria Angeles Rol
- Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
| | - Juan Antonio Madrid
- Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
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Chang Q, Berdyshev E, Cao D, Bogaard JD, White JJ, Chen S, Shah R, Mu W, Grantner R, Bettis S, Grassi MA. Cytochrome P450 2C epoxygenases mediate photochemical stress-induced death of photoreceptors. J Biol Chem 2014; 289:8337-52. [PMID: 24519941 DOI: 10.1074/jbc.m113.507152] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Degenerative loss of photoreceptors occurs in inherited and age-related retinal degenerative diseases. A chemical screen facilitates development of new testing routes for neuroprotection and mechanistic investigation. Herein, we conducted a mouse-derived photoreceptor (661W cell)-based high throughput screen of the Food and Drug Administration-approved Prestwick drug library to identify putative cytoprotective compounds against light-induced, synthetic visual chromophore-precipitated cell death. Different classes of hit compounds were identified, some of which target known genes or pathways pathologically associated with retinitis pigmentosa. Sulfaphenazole (SFZ), a selective inhibitor of human cytochrome P450 (CYP) 2C9 isozyme, was identified as a novel and leading cytoprotective compound. Expression of CYP2C proteins was induced by light. Gene-targeted knockdown of CYP2C55, the homologous gene of CYP2C9, demonstrated viability rescue to light-induced cell death, whereas stable expression of functional CYP2C9-GFP fusion protein further exacerbated light-induced cell death. Mechanistically, SFZ inhibited light-induced necrosis and mitochondrial stress-initiated apoptosis. Light elicited calcium influx, which was mitigated by SFZ. Light provoked the release of arachidonic acid from membrane phospholipids and production of non-epoxyeicosatrienoic acid metabolites. Administration of SFZ further stimulated the production of non-epoxyeicosatrienoic acid metabolites, suggesting a metabolic shift of arachidonic acid under inhibition of the CYP2C pathway. Together, our findings indicate that CYP2C genes play a direct causative role in photochemical stress-induced death of photoreceptors and suggest that the CYP monooxygenase system is a risk factor for retinal photodamage, especially in individuals with Stargardt disease and age-related macular degeneration that deposit condensation products of retinoids.
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Affiliation(s)
- Qing Chang
- From the Departments of Ophthalmology and Visual Sciences and
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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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Cyclic AMP-dependent regulation of tyrosine hydroxylase mRNA and immunofluorescence levels in rat retinal precursor cells. Cell Tissue Res 2013; 352:207-16. [PMID: 23355011 DOI: 10.1007/s00441-013-1555-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 01/03/2013] [Indexed: 10/27/2022]
Abstract
Stimulation of tyrosine hydroxylase (TH) gene transcription by cyclic AMP (cAMP) has been clearly established in adrenal medula cells and neural-crest-derived cell lines but information on this mechanism is still lacking in dopaminergic neurons. Because they are easily amenable to in vitro experiments, dopaminergic amacrine cells of the retina might constitute a valuable model system to study this mechanism. We have used real-time reverse transcription with the polymerase chain reaction to quantify TH mRNA levels in the rat retina during post-natal development and in retinal precursor cells obtained from neonatal rats and cultured for 3 days in serum-free medium. Whereas the TH mRNA concentration remains consistantly low in control cultures, treatment with cAMP-increasing agents (forskolin, membrane depolarization, phosphodiesterase inhibitors) is sufficient to raise it to the level observed in adult retina (15-fold increase). Treatment of the cultured cells can be delayed by up to 2 days with identical results at the TH mRNA level, thus ruling out a survival-promoting effect of cAMP. TH immunofluorescence has confirmed cAMP-dependent regulation of TH expression at the protein level and indicates that the frequency of TH-positive cells in the cultures is similar to that observed in the adult retina. Selective phosphodiesterase inhibitors suggest that PDE4 is the major subtype involved in the dopaminergic amacrine cell response. Our data clearly establish the cAMP-dependent regulation of TH mRNA and immunofluorescence levels in retinal precursor cells. The possible role of this regulation mechanism in the developmental activation of TH gene expression is discussed.
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Ruan GX, Gamble KL, Risner ML, Young LA, McMahon DG. Divergent roles of clock genes in retinal and suprachiasmatic nucleus circadian oscillators. PLoS One 2012; 7:e38985. [PMID: 22701739 PMCID: PMC3372489 DOI: 10.1371/journal.pone.0038985] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 05/17/2012] [Indexed: 11/24/2022] Open
Abstract
The retina is both a sensory organ and a self-sustained circadian clock. Gene targeting studies have revealed that mammalian circadian clocks generate molecular circadian rhythms through coupled transcription/translation feedback loops which involve 6 core clock genes, namely Period (Per) 1 and 2, Cryptochrome (Cry) 1 and 2, Clock, and Bmal1 and that the roles of individual clock genes in rhythms generation are tissue-specific. However, the mechanisms of molecular circadian rhythms in the mammalian retina are incompletely understood and the extent to which retinal neural clocks share mechanisms with the suprachiasmatic nucleus (SCN), the central neural clock, is unclear. In the present study, we examined the rhythmic amplitude and period of real-time bioluminescence rhythms in explants of retina from Per1-, Per2-, Per3-, Cry1-, Cry2-, and Clock-deficient mice that carried transgenic PERIOD2::LUCIFERASE (PER2::LUC) or Period1::luciferase (Per1::luc) circadian reporters. Per1-, Cry1- and Clock-deficient retinal and SCN explants showed weakened or disrupted rhythms, with stronger effects in retina compared to SCN. Per2, Per3, and Cry2 were individually dispensable for sustained rhythms in both tissues. Retinal and SCN explants from double knockouts of Cry1 and Cry2 were arrhythmic. Gene effects on period were divergent with reduction in the number of Per1 alleles shortening circadian period in retina, but lengthening it in SCN, and knockout of Per3 substantially shortening retinal clock period, but leaving SCN unaffected. Thus, the retinal neural clock has a unique pattern of clock gene dependence at the tissue level that it is similar in pattern, but more severe in degree, than the SCN neural clock, with divergent clock gene regulation of rhythmic period.
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Affiliation(s)
- Guo-Xiang Ruan
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Karen L. Gamble
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Michael L. Risner
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Laurel A. Young
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Douglas G. McMahon
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
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Richards AJ, Muller B, Shotwell M, Cowart LA, Rohrer B, Lu X. Assessing the functional coherence of gene sets with metrics based on the Gene Ontology graph. ACTA ACUST UNITED AC 2010; 26:i79-87. [PMID: 20529941 PMCID: PMC2881388 DOI: 10.1093/bioinformatics/btq203] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
MOTIVATION The results of initial analyses for many high-throughput technologies commonly take the form of gene or protein sets, and one of the ensuing tasks is to evaluate the functional coherence of these sets. The study of gene set function most commonly makes use of controlled vocabulary in the form of ontology annotations. For a given gene set, the statistical significance of observing these annotations or 'enrichment' may be tested using a number of methods. Instead of testing for significance of individual terms, this study is concerned with the task of assessing the global functional coherence of gene sets, for which novel metrics and statistical methods have been devised. RESULTS The metrics of this study are based on the topological properties of graphs comprised of genes and their Gene Ontology annotations. A novel aspect of these methods is that both the enrichment of annotations and the relationships among annotations are considered when determining the significance of functional coherence. We applied our methods to perform analyses on an existing database and on microarray experimental results. Here, we demonstrated that our approach is highly discriminative in terms of differentiating coherent gene sets from random ones and that it provides biologically sensible evaluations in microarray analysis. We further used examples to show the utility of graph visualization as a tool for studying the functional coherence of gene sets. AVAILABILITY The implementation is provided as a freely accessible web application at: http://projects.dbbe.musc.edu/gosteiner. Additionally, the source code written in the Python programming language, is available under the General Public License of the Free Software Foundation. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Adam J Richards
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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16
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Janus C, Welzl H. Mouse models of neurodegenerative diseases: criteria and general methodology. Methods Mol Biol 2010; 602:323-345. [PMID: 20012407 DOI: 10.1007/978-1-60761-058-8_19] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The major symptom of Alzheimer's disease is rapidly progressing dementia, coinciding with the formation of amyloid and tau deposits in the central nervous system, and neuronal death. At present familial cases of dementias provide the most promising foundation for modelling neurodegeneration. We describe the mnemonic and other major behavioral symptoms of tauopathies, briefly outline the genetics underlying familiar cases and discuss the arising implications for modelling the disease in mostly transgenic mouse lines. We then depict to what degree the most recent mouse models replicate pathological and cognitive characteristics observed in patients.There is no universally valid behavioral test battery to evaluate mouse models. The selection of individual tests depends on the behavioral and/or memory system in focus, the type of a model and how well it replicates the pathology of a disease and the amount of control over the genetic background of the mouse model. However it is possible to provide guidelines and criteria for modelling the neurodegeneration, setting up the experiments and choosing relevant tests. One should not adopt a "one (trans)gene, one disease" interpretation, but should try to understand how the mouse genome copes with the protein expression of the transgene in question. Further, it is not possible to recommend some mouse models over others since each model is valuable within its own constraints, and the way experiments are performed often reflects the idiosyncratic reality of specific laboratories. Our purpose is to improve bridging molecular and behavioural approaches in translational research.
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Affiliation(s)
- Christopher Janus
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, FL, USA
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Ruan GX, Allen GC, Yamazaki S, McMahon DG. An autonomous circadian clock in the inner mouse retina regulated by dopamine and GABA. PLoS Biol 2009; 6:e249. [PMID: 18959477 PMCID: PMC2567003 DOI: 10.1371/journal.pbio.0060249] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 09/05/2008] [Indexed: 11/20/2022] Open
Abstract
The influence of the mammalian retinal circadian clock on retinal physiology and function is widely recognized, yet the cellular elements and neural regulation of retinal circadian pacemaking remain unclear due to the challenge of long-term culture of adult mammalian retina and the lack of an ideal experimental measure of the retinal circadian clock. In the current study, we developed a protocol for long-term culture of intact mouse retinas, which allows retinal circadian rhythms to be monitored in real time as luminescence rhythms from a PERIOD2::LUCIFERASE (PER2::LUC) clock gene reporter. With this in vitro assay, we studied the characteristics and location within the retina of circadian PER2::LUC rhythms, the influence of major retinal neurotransmitters, and the resetting of the retinal circadian clock by light. Retinal PER2::LUC rhythms were routinely measured from whole-mount retinal explants for 10 d and for up to 30 d. Imaging of vertical retinal slices demonstrated that the rhythmic luminescence signals were concentrated in the inner nuclear layer. Interruption of cell communication via the major neurotransmitter systems of photoreceptors and ganglion cells (melatonin and glutamate) and the inner nuclear layer (dopamine, acetylcholine, GABA, glycine, and glutamate) did not disrupt generation of retinal circadian PER2::LUC rhythms, nor did interruption of intercellular communication through sodium-dependent action potentials or connexin 36 (cx36)-containing gap junctions, indicating that PER2::LUC rhythms generation in the inner nuclear layer is likely cell autonomous. However, dopamine, acting through D1 receptors, and GABA, acting through membrane hyperpolarization and casein kinase, set the phase and amplitude of retinal PER2::LUC rhythms, respectively. Light pulses reset the phase of the in vitro retinal oscillator and dopamine D1 receptor antagonists attenuated these phase shifts. Thus, dopamine and GABA act at the molecular level of PER proteins to play key roles in the organization of the retinal circadian clock. The circadian clock in the mammalian retina regulates many retinal functions, and its output modulates the central circadian clock in the brain. Details about the cellular location and neural regulation of the mammalian retinal circadian clock remain unclear, however, largely due to the difficulty of maintaining long-term culture of adult mammalian retina and the lack of an ideal experimental measure of the retinal clock. We have circumvented these limitations by developing a protocol for long-term culture of intact mouse retinas to monitor circadian rhythms of clock gene expression in real time. Using this protocol, we have localized expression of molecular retinal circadian rhythms to the inner nuclear layer. We find molecular retinal rhythms generation is independent of many forms of signaling from photoreceptors and ganglion cells, or major forms of neural communication within the inner nuclear layer, and have characterized light-induced resetting of the retinal clock. Retinal dopamine and GABA, although not necessary for the generation of molecular retinal rhythms, were revealed to regulate the phase and amplitude of retinal molecular rhythms, respectively, with dopamine participating in light-induced resetting. Our data indicate that dopamine and GABA play prominent roles in the organization of the retinal circadian clock. Long-term culture of mouse retinas reveals a circadian clock in the inner retina that can be reset by light and is regulated by the neurotransmitters dopamine and GABA.
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18
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Janus C. Conditionally inducible tau mice - designing a better mouse model of neurodegenerative diseases. GENES BRAIN AND BEHAVIOR 2008; 7 Suppl 1:12-27. [PMID: 18184367 DOI: 10.1111/j.1601-183x.2007.00375.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- C Janus
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, FL 32224, USA.
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19
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Liu H, Zhao M, Opere CA. Prejunctional inhibitory effects of isoprostanes on dopaminergic neurotransmission in bovine retinae, in vitro. Neurochem Res 2007; 33:37-42. [PMID: 17674205 DOI: 10.1007/s11064-007-9404-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Accepted: 06/05/2007] [Indexed: 11/29/2022]
Abstract
We investigated the effect of isoprostanes (IsoPs) on potassium (K+)-depolarization-evoked release of [3H]dopamine from isolated bovine retinae. Isolated retinae were preloaded with [3H]dopamine and then prepared for studies of [3H]dopamine release using the superfusion method. 8-iso(15R)PGF 2alpha, 8-isoPGE2, 8-isoPGE1 and 8-isoPGF 2alpha attenuated [3H]dopamine release from isolated bovine retinae. At a concentration of 1 microM, the rank order of activity displayed by IsoP agonists was: 8-iso(15R)PGF 2alpha > 8-isoPGE2 > 8-isoPGE1 > 8-isoPGF 2alpha. Inhibition of cyclooxygenase (COX) with flurbiprofen reversed the effects caused by 8-isoPGE2 (10 nM and 10 microM), 8-iso(15R)PGF 2alpha (1 microM) and 8-isoPGE1 (1 microM). Although the EP1/EP2 antagonist, AH 6809 (10 microM) had no significant effect on K+-induced [3H]dopamine release, it blocked the inhibitory effect of both 8-isoPGE1 (10 microM) and 8-isoPGE2 (10 microM). In conclusion, IsoPs attenuate K+-induced [3H]dopamine release in isolated bovine retinae, presumably via an indirect action on COX pathway leading to the production of prostanoids, which in turn, activates EP receptors.
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Affiliation(s)
- Hong Liu
- Department of Ophthalmology, Sichuan Provincial People Hospital, Chengdu, Sichuan 610072, PR China
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20
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Eriksen JL, Janus CG. Plaques, tangles, and memory loss in mouse models of neurodegeneration. Behav Genet 2006; 37:79-100. [PMID: 17072762 DOI: 10.1007/s10519-006-9118-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Accepted: 09/21/2006] [Indexed: 10/24/2022]
Abstract
Within the past decade, our understanding of the pathogenic mechanisms in Alzheimer's disease (AD) has dramatically advanced because of the development of transgenic mouse models that recapitulate the key pathological and behavioral phenotypes of the disease. These mouse models have allowed investigators to test detailed questions about how pathology develops and to evaluate potential therapeutic approaches that could slow down the development of this disease. In this review, we discuss the status of transgenic mouse models and review the complex relationship between pathology and behavior in the development of neuropathological syndromes in AD.
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Affiliation(s)
- Jason L Eriksen
- Department of Neuroscience, Mayo Clinic Jacksonville, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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21
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Ruan GX, Zhang DQ, Zhou T, Yamazaki S, McMahon DG. Circadian organization of the mammalian retina. Proc Natl Acad Sci U S A 2006; 103:9703-8. [PMID: 16766660 PMCID: PMC1480470 DOI: 10.1073/pnas.0601940103] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mammalian retina contains an endogenous circadian pacemaker that broadly regulates retinal physiology and function, yet the cellular origin and organization of the mammalian retinal circadian clock remains unclear. Circadian clock neurons generate daily rhythms via cell-autonomous autoregulatory clock gene networks, and, thus, to localize circadian clock neurons within the mammalian retina, we have studied the cell type-specific expression of six core circadian clock genes in individual, identified mouse retinal neurons, as well as characterized the clock gene expression rhythms in photoreceptor degenerate rd mouse retinas. Individual photoreceptors, horizontal, bipolar, dopaminergic (DA) amacrines, catecholaminergic (CA) amacrines, and ganglion neurons were identified either by morphology or by a tyrosine hydroxylase (TH) promoter-driven red fluorescent protein (RFP) fluorescent reporter. Cells were collected, and their transcriptomes were subjected to multiplex single-cell RT-PCR for the core clock genes Period (Per) 1 and 2, Cryptochrome (Cry) 1 and 2, Clock, and Bmal1. Individual horizontal, bipolar, DA, CA, and ganglion neurons, but not photoreceptors, were found to coordinately express all six core clock genes, with the lowest proportion of putative clock cells in photoreceptors (0%) and the highest proportion in DA neurons (30%). In addition, clock gene rhythms were found to persist for >25 days in isolated, cultured rd mouse retinas in which photoreceptors had degenerated. Our results indicate that multiple types of retinal neurons are potential circadian clock neurons that express key elements of the circadian autoregulatory gene network and that the inner nuclear and ganglion cell layers of the mammalian retina contain functionally autonomous circadian clocks.
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Affiliation(s)
- Guo-Xiang Ruan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Dao-Qi Zhang
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Tongrong Zhou
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Shin Yamazaki
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Douglas G. McMahon
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
- *To whom correspondence should be addressed at:
Department of Biological Sciences, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235-1634. E-mail:
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22
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SanGiovanni JP, Chew EY. The role of omega-3 long-chain polyunsaturated fatty acids in health and disease of the retina. Prog Retin Eye Res 2005; 24:87-138. [PMID: 15555528 DOI: 10.1016/j.preteyeres.2004.06.002] [Citation(s) in RCA: 491] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In this work we advance the hypothesis that omega-3 (omega-3) long-chain polyunsaturated fatty acids (LCPUFAs) exhibit cytoprotective and cytotherapeutic actions contributing to a number of anti-angiogenic and neuroprotective mechanisms within the retina. omega-3 LCPUFAs may modulate metabolic processes and attenuate effects of environmental exposures that activate molecules implicated in pathogenesis of vasoproliferative and neurodegenerative retinal diseases. These processes and exposures include ischemia, chronic light exposure, oxidative stress, inflammation, cellular signaling mechanisms, and aging. A number of bioactive molecules within the retina affect, and are effected by such conditions. These molecules operate within complex systems and include compounds classified as eicosanoids, angiogenic factors, matrix metalloproteinases, reactive oxygen species, cyclic nucleotides, neurotransmitters and neuromodulators, pro-inflammatory and immunoregulatory cytokines, and inflammatory phospholipids. We discuss the relationship of LCPUFAs with these bioactivators and bioactive compounds in the context of three blinding retinal diseases of public health significance that exhibit both vascular and neural pathology. How is omega-3 LCPUFA status related to retinal structure and function? Docosahexaenoic acid (DHA), a major dietary omega-3 LCPUFA, is also a major structural lipid of retinal photoreceptor outer segment membranes. Biophysical and biochemical properties of DHA may affect photoreceptor membrane function by altering permeability, fluidity, thickness, and lipid phase properties. Tissue DHA status affects retinal cell signaling mechanisms involved in phototransduction. DHA may operate in signaling cascades to enhance activation of membrane-bound retinal proteins and may also be involved in rhodopsin regeneration. Tissue DHA insufficiency is associated with alterations in retinal function. Visual processing deficits have been ameliorated with DHA supplementation in some cases. What evidence exists to suggest that LCPUFAs modulate factors and processes implicated in diseases of the vascular and neural retina? Tissue status of LCPUFAs is modifiable by and dependent upon dietary intake. Certain LCPUFAs are selectively accreted and efficiently conserved within the neural retina. On the most basic level, omega-3 LCPUFAs influence retinal cell gene expression, cellular differentiation, and cellular survival. DHA activates a number of nuclear hormone receptors that operate as transcription factors for molecules that modulate reduction-oxidation-sensitive and proinflammatory genes; these include the peroxisome proliferator-activated receptor-alpha (PPAR-alpha) and the retinoid X receptor. In the case of PPAR-alpha, this action is thought to prevent endothelial cell dysfunction and vascular remodeling through inhibition of: vascular smooth muscle cell proliferation, inducible nitric oxide synthase production, interleukin-1 induced cyclooxygenase (COX)-2 production, and thrombin-induced endothelin 1 production. Research on model systems demonstrates that omega-3 LCPUFAs also have the capacity to affect production and activation of angiogenic growth factors, arachidonic acid (AA)-based vasoregulatory eicosanoids, and MMPs. Eicosapentaenoic acid (EPA), a substrate for DHA, is the parent fatty acid for a family of eicosanoids that have the potential to affect AA-derived eicosanoids implicated in abnormal retinal neovascularization, vascular permeability, and inflammation. EPA depresses vascular endothelial growth factor (VEGF)-specific tyrosine kinase receptor activation and expression. VEGF plays an essential role in induction of: endothelial cell migration and proliferation, microvascular permeability, endothelial cell release of metalloproteinases and interstitial collagenases, and endothelial cell tube formation. The mechanism of VEGF receptor down-regulation is believed to occur at the tyrosine kinase nuclear factor-kappa B (NFkappaB). NFkappaB is a nuclear transcription factor that up-regulates COX-2 expression, intracellular adhesion molecule, thrombin, and nitric oxide synthase. All four factors are associated with vascular instability. COX-2 drives conversion of AA to a number angiogenic and proinflammatory eicosanoids. Our general conclusion is that there is consistent evidence to suggest that omega-3 LCPUFAs may act in a protective role against ischemia-, light-, oxygen-, inflammatory-, and age-associated pathology of the vascular and neural retina.
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Affiliation(s)
- John Paul SanGiovanni
- Division of Epidemiology and Clinical Research, National Eye Insitute, National Institutes of Health, 31 Center Drive, Building 31, Room 6A52, MSC 2510, Bethesda, MD 20892-2510, USA.
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23
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Linden R, Martins RAP, Silveira MS. Control of programmed cell death by neurotransmitters and neuropeptides in the developing mammalian retina. Prog Retin Eye Res 2004; 24:457-91. [PMID: 15845345 DOI: 10.1016/j.preteyeres.2004.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
It has long been known that a barrage of signals from neighboring and connecting cells, as well as components of the extracellular matrix, control cell survival. Given the extensive repertoire of retinal neurotransmitters, neuromodulators and neurotrophic factors, and the exhuberant interconnectivity of retinal interneurons, it is likely that various classes of released neuroactive substances may be involved in the control of sensitivity to retinal cell death. The aim of this article is to review evidence that neurotransmitters and neuropeptides control the sensitivity to programmed cell death in the developing retina. Whereas the best understood mechanism of execution of cell death is that of caspase-mediated apoptosis, current evidence shows that not only there are many parallel pathways to apoptotic cell death, but non-apoptotic programs of execution of cell death are also available, and may be triggered either in isolation or combined with apoptosis. The experimental data show that many upstream signaling pathways can modulate cell death, including those dependent on the second messengers cAMP-PKA, calcium and nitric oxide. Evidence for anterograde neurotrophic control is provided by a variety of models of the central nervous system, and the data reviewed here indicate that an early function of certain neurotransmitters, such as glutamate and dopamine, as well as neuropeptides such as pituitary adenylyl cyclase-activating polypeptide and vasoactive intestinal peptide is the trophic support of cell populations in the developing retina. This may have implications both regarding the mechanisms of retinal organogenesis, as well as pathological conditions leading to retinal dystrophies and to dysfunctional cellular behavior.
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Affiliation(s)
- Rafael Linden
- Centro de Ciencias da Saude, Instituto de Biofísica da UFRJ, Cidade Universitária, bloco G, Rio de Janeiro 21949-900, Brazil.
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24
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Arendash GW, Lewis J, Leighty RE, McGowan E, Cracchiolo JR, Hutton M, Garcia MF. Multi-metric behavioral comparison of APPsw and P301L models for Alzheimer's disease: linkage of poorer cognitive performance to tau pathology in forebrain. Brain Res 2004; 1012:29-41. [PMID: 15158158 DOI: 10.1016/j.brainres.2004.02.081] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2004] [Indexed: 12/31/2022]
Abstract
APPsw transgenic mice bearing the "Swedish" amyloid precursor protein (APP) mutation and JNPL3 transgenic mice bearing the P301L (Tau) mutation were compared to control non-transgenic (NT) mice in an extensive behavioral test battery administered between 5 and 8.5 months of age. APP mice were impaired in a variety of cognitive-based tasks prior to overt Abeta plaque development, making involvement of mutant APP overexpression and/or oligomeric Abeta assemblies most likely. Although Tau mice, as a group, were not impaired in any single behavioral measure, a collective assessment of behavioral measures through discriminant function analysis showed that Tau mice were impaired in overall behavioral (cognitive) performance. Moreover, correlation analyses involving Tau mice alone revealed linkage between poorer cognitive performance in all three water maze tasks and the number of neurofibrillary tangle (NFT)-containing neurons in neocortex and hippocampus. These findings indicate that: (1) APP mice show early and extensive cognitive impairment before evident Abeta deposition, and (2) the process or product of NFT formation in Tau mice is sufficient to deleteriously impact cognitive performance.
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Affiliation(s)
- Gary W Arendash
- The Johnnie B. Byrd Alzhimer's Center and Research Institute, Tampa, FL 33620, USA.
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Garcia MF, Gordon MN, Hutton M, Lewis J, McGowan E, Dickey CA, Morgan D, Arendash GW. The retinal degeneration (rd) gene seriously impairs spatial cognitive performance in normal and Alzheimer's transgenic mice. Neuroreport 2004; 15:73-7. [PMID: 15106834 DOI: 10.1097/00001756-200401190-00015] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To determine the effects of the recessive retinal degeneration (rd) gene on behavioral performance, three Alzheimer's transgenic lines (APPsw, P301L, APPsw + P301L) and non-transgenic littermates were evaluated in a comprehensive behavioral battery between 5 and 8.5 months of age. For all four genotypes collectively, rd homozygosity resulted in profound impairment in spatial cognitive tasks requiring visual acuity (Morris maze, platform recognition, and radial arm water maze). Non-transgenic and P301L mutant tau mice contributed most to this rd effect since heterozygous and wild type mice performed well. By contrast, spatial cognitive performance of both APPsw-expressing lines was often impaired, irrespective of rd status. Sensorimotor performance was unaffected by rd homozygosity, while rd effects on anxiety were genotype-dependent (less anxiety in NT, APPsw; more anxiety in P301L, APPsw + P301L). Our results strongly encourage rd screening of genetically manipulated mouse lines produced from rd-carrying strain backgrounds to avoid serious potential confounds in the interpretation of spatially based cognitive performance.
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Affiliation(s)
- M F Garcia
- Memory and Aging Research Laboratory, SCA110, University of South Florida, Tampa, FL 33620, USA
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