151
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Schottler J, Randoll N, Lucius R, Caliebe A, Roider J, Klettner A. Long-term treatment with anti-VEGF does not induce cell aging in primary retinal pigment epithelium. Exp Eye Res 2018. [DOI: 10.1016/j.exer.2018.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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152
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Fisher CR, Ferrington DA. Perspective on AMD Pathobiology: A Bioenergetic Crisis in the RPE. Invest Ophthalmol Vis Sci 2018; 59:AMD41-AMD47. [PMID: 30025108 PMCID: PMC5989860 DOI: 10.1167/iovs.18-24289] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
AMD is the leading cause of blindness in developed countries. The dry form of AMD, also known as atrophic AMD, is characterized by the death of RPE and photoreceptors. Currently, there are no treatments for this form of the disease due in part to our incomplete understanding of the mechanism causing AMD. Strong experimental evidence from studies of human donors with AMD supports the emerging hypothesis that defects in RPE mitochondria drive AMD pathology. These studies, using different experimental methods, have shown disrupted RPE mitochondrial architecture and decreased mitochondrial number and mass, altered content of multiple mitochondrial proteins, increased mitochondrial DNA damage that correlates with disease severity, and defects in bioenergetics for primary RPE cultures from AMD donors. Herein, we discuss a model of metabolic uncoupling that alters bioenergetics in the diseased retina and drives AMD pathology. These data provide the rationale for targeting the mitochondria in the RPE as the most efficacious intervention strategy if administered early, before vision loss and cell death.
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Affiliation(s)
- Cody R. Fisher
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
,Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
,Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States
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153
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Dejos C, Kuny S, Han WH, Capel H, Lemieux H, Sauvé Y. Photoreceptor-induced RPE phagolysosomal maturation defects in Stargardt-like Maculopathy (STGD3). Sci Rep 2018; 8:5944. [PMID: 29654292 PMCID: PMC5899129 DOI: 10.1038/s41598-018-24357-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 03/28/2018] [Indexed: 11/09/2022] Open
Abstract
For many neurodegenerative disorders, expression of a pathological protein by one cell type impedes function of other cell types, which in turn contributes to the death of the first cell type. In transgenic mice modelling Stargardt-like (STGD3) maculopathy, human mutant ELOVL4 expression by photoreceptors is associated with defects in the underlying retinal pigment epithelium (RPE). To examine how photoreceptors exert cytotoxic effects on RPE cells, transgenic ELOVL4 (TG1-2 line; TG) and wild-type (WT) littermates were studied one month prior (preclinical stage) to onset of photoreceptor loss (two months). TG photoreceptor outer segments presented to human RPE cells are recognized and internalized into phagosomes, but their digestion is delayed. Live RPE cell imaging pinpoints decreased numbers of acidified phagolysomes. In vivo, master regulator of lysosomal genes, transcription factor EB (TFEB), and key lysosomal enzyme Cathepsin D are both unaffected. Oxidative stress, as ruled out with high-resolution respirometry, does not play a role at such an early stage. Upregulation of CRYBA1/A3 and phagocytic cells (microglia/macrophages) interposed between RPE and photoreceptors support adaptive responses to processing delays. Impaired phagolysosomal maturation is observed in RPE of mice expressing human mutant ELOVL4 in their photoreceptors prior to photoreceptor death and associated vision loss.
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Affiliation(s)
- Camille Dejos
- Department of Ophthalmology and Visual Sciences, University of Alberta, 7-45 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada
| | - Sharee Kuny
- Department of Ophthalmology and Visual Sciences, University of Alberta, 7-45 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada
| | - Woo Hyun Han
- Department of Ophthalmology and Visual Sciences, University of Alberta, 7-45 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada
| | - Heather Capel
- Department of Physiology, University of Alberta, 7-45 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada
| | - Hélène Lemieux
- Faculty Saint-Jean, University of Alberta, 8406 Rue Marie-Anne Gaboury Northwest, Edmonton, AB, T6C 4G9, Canada
| | - Yves Sauvé
- Department of Ophthalmology and Visual Sciences, University of Alberta, 7-45 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada. .,Department of Physiology, University of Alberta, 7-45 Medical Sciences Building, Edmonton, AB, T6G 2H7, Canada.
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154
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Gupta RK, Kaur I, Nag TC, Chhablani J. Diagnostic Electron Microscopy of Retina. Semin Ophthalmol 2018; 33:700-710. [PMID: 29388866 DOI: 10.1080/08820538.2017.1416415] [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] [Indexed: 10/18/2022]
Abstract
The electron microscopy techniques were used in various fields as an analytical technique under in vitro conditions, which provides the sufficient resolution for better visualization and interpretation. This review gives a brief overview of the analytical application of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques and critical findings in different retinal pathologies. This review article aims to improvise understanding of retinal microstructures for clinicians which will help to improve the interpretation of the current advanced imaging techniques.
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Affiliation(s)
- Rishikesh Kumar Gupta
- a Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre , L V Prasad Eye Institute (KAR Campus) , Hyderabad , Telangana , India
| | - Inderjeet Kaur
- a Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre , L V Prasad Eye Institute (KAR Campus) , Hyderabad , Telangana , India
| | - Tapas C Nag
- c All India Institute of Medical Sciences , Department of Anatomy , New Delhi , India
| | - Jay Chhablani
- b Smt. Kanuri Santhamma Centre for Vitreo-Retinal Diseases , L V Prasad Eye Institute (KAR Campus) , Hyderabad , Telangana , India
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155
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Sastre-Ibáñez M, Barreiro-González A, Gallego-Pinazo R, Dolz-Marco R, García-Armendariz B. Geographic atrophy: Etiopathogenesis and current therapies. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2018; 93:22-34. [PMID: 28886928 DOI: 10.1016/j.oftal.2017.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 06/07/2023]
Abstract
Geographic atrophy is characterized by severe visual deficit whose etiology and pathophysiology are yet to be elucidated. As a working hypothesis, oxidative damage could trigger a chronic inflammation in Bruch's membrane-RPE-choriocapillaris complex, mostly due to complement pathway overactivation. Some individuals with mutations in the complement system and other factors have diminished capacity in the modulation of the inflammatory response, which results in cell damage and waste accumulation. This accumulation of intracellular and extracellular waste products manifests as drusen and pigmentary changes that precede the atrophy of photoreceptors, RPE, choriocapillaris with an ischemic process with decreased choroid flow. All these processes can be detected as tomographic findings and autofluorescence signals that are useful in the evaluation of patients with atrophic AMD, which helps to establish an individualized prognosis. Anti-inflammatory, antioxidant and therapies that decrease the accumulation of toxins for the preservation of the RPE cells and photoreceptors are being investigated in order to slow down the progression of this disease.
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Affiliation(s)
- M Sastre-Ibáñez
- Servicio de Oftalmología, Hospital Clínico San Carlos, Madrid, España.
| | - A Barreiro-González
- Servicio de Oftalmología, Hospital Universitario y Politécnico La Fe, Valencia, España
| | - R Gallego-Pinazo
- Servicio de Oftalmología, Hospital Universitario y Politécnico La Fe, Valencia, España
| | - R Dolz-Marco
- Servicio de Oftalmología, Hospital Universitario y Politécnico La Fe, Valencia, España
| | - B García-Armendariz
- Servicio de Oftalmología, Hospital Universitario y Politécnico La Fe, Valencia, España
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156
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Kerur N, Fukuda S, Banerjee D, Kim Y, Fu D, Apicella I, Varshney A, Yasuma R, Fowler BJ, Baghdasaryan E, Marion KM, Huang X, Yasuma T, Hirano Y, Serbulea V, Ambati M, Ambati VL, Kajiwara Y, Ambati K, Hirahara S, Bastos-Carvalho A, Ogura Y, Terasaki H, Oshika T, Kim KB, Hinton DR, Leitinger N, Cambier JC, Buxbaum JD, Kenney MC, Jazwinski SM, Nagai H, Hara I, West AP, Fitzgerald KA, Sadda SR, Gelfand BD, Ambati J. cGAS drives noncanonical-inflammasome activation in age-related macular degeneration. Nat Med 2017; 24:50-61. [PMID: 29176737 PMCID: PMC5760363 DOI: 10.1038/nm.4450] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 10/31/2017] [Indexed: 02/07/2023]
Abstract
Geographic atrophy is a blinding form of age-related macular degeneration characterized by death of the retinal pigmented epithelium (RPE). In this disease, the RPE displays evidence of DICER1 deficiency, resultant accumulation of endogenous Alu retroelement RNA, and NLRP3 inflammasome activation. How the inflammasome is activated in this untreatable disease is largely unknown. Here we demonstrate that RPE degeneration in human cell culture and in mouse models is driven by a non-canonical inflammasome pathway that results in activation of caspase-4 (caspase-11 in mice) and caspase-1, and requires cyclic GMP-AMP synthase (cGAS)-dependent interferon-β (IFN-β) production and gasdermin D-dependent interleukin-18 (IL-18) secretion. Reduction of DICER1 levelsor accumulation of Alu RNA triggers cytosolic escape of mitochondrial DNA, which engages cGAS. Moreover, caspase-4, gasdermin D, IFN-β, and cGAS levels are elevated in the RPE of human eyes with geographic atrophy. Collectively, these data highlight an unexpected role for cGAS in responding to mobile element transcripts, reveal cGAS-driven interferon signaling as a conduit for mitochondrial damage-induced inflammasome activation, expand the immune sensing repertoire of cGAS and caspase-4 to non-infectious human disease, and identify new potential targets for treatment of a major cause of blindness.
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Affiliation(s)
- Nagaraj Kerur
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Shinichi Fukuda
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan
| | - Daipayan Banerjee
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Younghee Kim
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Dongxu Fu
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Ivana Apicella
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Akhil Varshney
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Reo Yasuma
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Benjamin J Fowler
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Elmira Baghdasaryan
- Doheny Eye Institute, Los Angeles, Los Angeles, California, USA.,Department of Ophthalmology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California, USA
| | | | - Xiwen Huang
- Doheny Eye Institute, Los Angeles, Los Angeles, California, USA
| | - Tetsuhiro Yasuma
- Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan.,Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshio Hirano
- Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan.,Department of Ophthalmology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Vlad Serbulea
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Meenakshi Ambati
- Center for Digital Image Evaluation, Charlottesville, Virginia, USA
| | - Vidya L Ambati
- Center for Digital Image Evaluation, Charlottesville, Virginia, USA
| | - Yuji Kajiwara
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kameshwari Ambati
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Shuichiro Hirahara
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Ana Bastos-Carvalho
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Yuichiro Ogura
- Department of Ophthalmology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tetsuro Oshika
- Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan
| | - Kyung Bo Kim
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - David R Hinton
- Departments of Pathology and Ophthalmology, USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Norbert Leitinger
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - John C Cambier
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Joseph D Buxbaum
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - M Cristina Kenney
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - S Michal Jazwinski
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Hiroshi Nagai
- Division of Dermatology, Department of Internal Related, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Isao Hara
- Department of Urology, Wakayama Medical University, Wakayama, Japan
| | - A Phillip West
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, Texas, USA
| | - Katherine A Fitzgerald
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - SriniVas R Sadda
- Doheny Eye Institute, Los Angeles, Los Angeles, California, USA.,Department of Ophthalmology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California, USA
| | - Bradley D Gelfand
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA.,Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, Kentucky, USA.,Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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157
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Wu S, Lu Q, Wang N, Zhang J, Liu Q, Gao M, Chen J, Liu W, Xu L. Cyclic stretch induced-retinal pigment epithelial cell apoptosis and cytokine changes. BMC Ophthalmol 2017; 17:208. [PMID: 29166888 PMCID: PMC5700533 DOI: 10.1186/s12886-017-0606-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/15/2017] [Indexed: 11/12/2022] Open
Abstract
Background The pathogenesis of age-related macular degeneration (AMD) is complex. It has been shown that vitreomacular traction (VMT) plays a role in the pathogenesis of AMD. We speculate that the continuous stretch induced by VMT might impair the function of retinal pigment epithelium (RPE) cells and it might also be involved in the progression of AMD. Methods Cultured ARPE-19 cells were subjected to cyclic stretch on the Flexcell Strain system at a level of 25% increment on the surface area for 8 h, 14 h, 20 h, 24 h. In another group, the stretch was withdrawn at 14 h and the cell cultured for another 6 h. Then, we observed the changes in morphology, apoptosis and expression of interleukin 6 (IL6) and vascular endothelial growth factor (VEGF) in RPE cells under stretch. Results We found that stretch induced the RPE cells to change from a spreading shape into a rounded shape, and that the morphological changes were positively correlated with the duration of the stretch. The expression of pFAK397 and pRac1/cdc42 were elevated in a time-dependent fashion. The stretch resulted in an increase in the apoptosis ratio, with Bcl2, Bax and p53 also showing time-dependent changes. In addition, up-regulation of IL6 and VEGF expression levels was also observed. After withdrawal of the stretch, all of these changes were significantly diminished. Conclusion Stretch may induce morphological, cell apoptosis, and up-regulation of cytokines changes in RPE cells, indicating that cyclic stretching may participate in the progression of AMD by impeding the functions of the RPE.
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Affiliation(s)
- Shen Wu
- Beijing Institute of Ophthalmology; Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China
| | - Qingjun Lu
- China-Japan Friendship Hospital, Beijing, 100029, China
| | - Ningli Wang
- Beijing Institute of Ophthalmology; Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China
| | - Jingxue Zhang
- Beijing Institute of Ophthalmology; Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China
| | - Qian Liu
- Beijing Institute of Ophthalmology; Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China
| | - Meng Gao
- Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China
| | - Jinqiu Chen
- Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China
| | - Wu Liu
- Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China.
| | - Liang Xu
- Beijing Institute of Ophthalmology; Beijing Tongren Eye Center; Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100005, China.
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158
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Joyal JS, Gantner ML, Smith LEH. Retinal energy demands control vascular supply of the retina in development and disease: The role of neuronal lipid and glucose metabolism. Prog Retin Eye Res 2017; 64:131-156. [PMID: 29175509 DOI: 10.1016/j.preteyeres.2017.11.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/11/2017] [Accepted: 11/15/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Jean-Sébastien Joyal
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Qc, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, Qc, Canada.
| | - Marin L Gantner
- The Lowy Medical Research Institute, La Jolla, United States
| | - Lois E H Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston MA 02115, United States.
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159
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Pollreisz A, Messinger JD, Sloan KR, Mittermueller TJ, Weinhandl AS, Benson EK, Kidd GJ, Schmidt-Erfurth U, Curcio CA. Visualizing melanosomes, lipofuscin, and melanolipofuscin in human retinal pigment epithelium using serial block face scanning electron microscopy. Exp Eye Res 2017; 166:131-139. [PMID: 29066281 DOI: 10.1016/j.exer.2017.10.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 10/18/2022]
Abstract
To assess serial section block-face scanning electron microscopy (SBFSEM) for retinal pigment epithelium (RPE) ultrastructure, we determined the number and distribution within RPE cell bodies of melanosomes (M), lipofuscin (L), and melanolipofuscin (ML). Eyes of 4 Caucasian donors (16M, 32F, 76F, 84M) with unremarkable maculas were sectioned and imaged using an SEM fitted with an in-chamber automated ultramicrotome. Aligned image stacks were generated by alternately imaging an epoxy resin block face using backscattered electrons, then removing a 125 nm-thick layer. Series of 249-499 sections containing 5-24 nuclei were examined per eye. Trained readers manually assigned boundaries of individual cells and x,y,z locations of M, L, and ML. A Density Recovery Profile was computed in three dimensions for M, L, and ML. The number of granules per RPE cell body in 16M, 32F, 76F, and 84M eyes, respectively, was 465 ± 127 (mean ± SD), 305 ± 92, 79 ± 40, and 333 ± 134 for L; 13 ± 9; 6 ± 7, 131 ± 55, and 184 ± 66 for ML; and 29 ± 19, 24 ± 12, 12 ± 7, and 7 ± 3 for M. Granule types were spatially organized, with M near apical processes. The effective radius, a sphere of decreased probability for granule occurrence, was 1 μm for L, ML, and M combined. In conclusion, SBFEM reveals that adult human RPE has hundreds of L, LF, and M and that granule spacing is regulated by granule size alone. When obtained for a larger sample, this information will enable hypothesis testing about organelle turnover and regulation in health, aging, and disease, and elucidate how RPE-specific signals are generated in clinical optical coherence tomography and autofluorescence imaging.
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Affiliation(s)
| | - Jeffrey D Messinger
- Ophthalmology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kenneth R Sloan
- Ophthalmology, University of Alabama at Birmingham, Birmingham, AL, United States; Computer Science, University of Alabama at Birmingham, Birmingham, AL, United States
| | | | | | | | - Grahame J Kidd
- Renovo Neural Inc., Cleveland, OH, United States; Neurosciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, United States
| | | | - Christine A Curcio
- Ophthalmology, University of Alabama at Birmingham, Birmingham, AL, United States.
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160
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Chichagova V, Hallam D, Collin J, Buskin A, Saretzki G, Armstrong L, Yu-Wai-Man P, Lako M, Steel DH. Human iPSC disease modelling reveals functional and structural defects in retinal pigment epithelial cells harbouring the m.3243A > G mitochondrial DNA mutation. Sci Rep 2017; 7:12320. [PMID: 28951556 PMCID: PMC5615077 DOI: 10.1038/s41598-017-12396-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 09/08/2017] [Indexed: 01/19/2023] Open
Abstract
The m.3243A > G mitochondrial DNA mutation was originally described in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The phenotypic spectrum of the m.3243A > G mutation has since expanded to include a spectrum of neuromuscular and ocular manifestations, including reduced vision with retinal degeneration, the underlying mechanism of which remains unclear. We used dermal fibroblasts, from patients with retinal pathology secondary to the m.3243A > G mutation to generate heteroplasmic induced pluripotent stem cell (hiPSC) clones. RPE cells differentiated from these hiPSCs contained morphologically abnormal mitochondria and melanosomes, and exhibited marked functional defects in phagocytosis of photoreceptor outer segments. These findings have striking similarities to the pathological abnormalities reported in RPE cells studied from post-mortem tissues of affected m.3243A > G mutation carriers. Overall, our results indicate that RPE cells carrying the m.3243A > G mutation have a reduced ability to perform the critical physiological function of phagocytosis. Aberrant melanosomal morphology may potentially have consequences on the ability of the cells to perform another important protective function, namely absorption of stray light. Our in vitro cell model could prove a powerful tool to further dissect the complex pathophysiological mechanisms that underlie the tissue specificity of the m.3243A > G mutation, and importantly, allow the future testing of novel therapeutic agents.
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Affiliation(s)
- Valeria Chichagova
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Joseph Collin
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Adriana Buskin
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Gabriele Saretzki
- Institute for Cell and Molecular Biosciences and The Ageing Biology Centre, Campus for Ageing and Vitality, Newcastle University, NE4 5PL, United Kingdom
| | - Lyle Armstrong
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, United Kingdom
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, United Kingdom
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, EC1V 2PD, United Kingdom
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom.
| | - David H Steel
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom.
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161
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Crooke A, Huete-Toral F, Colligris B, Pintor J. The role and therapeutic potential of melatonin in age-related ocular diseases. J Pineal Res 2017; 63. [PMID: 28658514 DOI: 10.1111/jpi.12430] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/23/2017] [Indexed: 12/20/2022]
Abstract
The eye is continuously exposed to solar UV radiation and pollutants, making it prone to oxidative attacks. In fact, oxidative damage is a major cause of age-related ocular diseases including cataract, glaucoma, age-related macular degeneration, and diabetic retinopathy. As the nature of lens cells, trabecular meshwork cells, retinal ganglion cells, retinal pigment epithelial cells, and photoreceptors is postmitotic, autophagy plays a critical role in their cellular homeostasis. In age-related ocular diseases, this process is impaired, and thus, oxidative damage becomes irreversible. Other conditions such as low-grade chronic inflammation and angiogenesis also contribute to the development of retinal diseases (glaucoma, age-related macular degeneration and diabetic retinopathy). As melatonin is known to have remarkable qualities such as antioxidant/antinitridergic, mitochondrial protector, autophagy modulator, anti-inflammatory, and anti-angiogenic, it can represent a powerful tool to counteract all these diseases. The present review analyzes the role and therapeutic potential of melatonin in age-related ocular diseases, focusing on nitro-oxidative stress, autophagy, inflammation, and angiogenesis mechanisms.
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Affiliation(s)
- Almudena Crooke
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Fernando Huete-Toral
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Basilio Colligris
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
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162
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Li H, Chintalapudi SR, Jablonski MM. Current drug and molecular therapies for the treatment of atrophic age-related macular degeneration: phase I to phase III clinical development. Expert Opin Investig Drugs 2017; 26:1103-1114. [PMID: 28816076 DOI: 10.1080/13543784.2017.1369042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Age-related macular degeneration (AMD) is the leading cause of vision loss among the elderly. Atrophic AMD, including early, intermediate and geographic atrophy (GA), accounts for ~90% of all cases. It is a multifactorial degeneration characterized by chronic inflammation, oxidative stress and aging components. Although no FDA-approved treatment yet exists for the late stage of atrophic AMD, multiple pathological mechanisms are partially known and several promising therapies are in various stages of development. Areas covered: Underlying mechanisms that define atrophic AMD will help provide novel therapeutic targets that will address this largely unmet clinical need. The purpose of this paper is to review current promising drugs that are being evaluated in clinical trials. Because no pharmacological treatments are currently available for late stage of atrophic AMD, any new therapy would have extensive market potential. Expert opinion: The number of AMD patients is predicted to increase to ~30 million worldwide by 2020. In response to this enormous unmet clinical need, new promising therapies are being developed and evaluated in clinical trials. We propose that the assessment of novel interventions will also need to consider the genotypes of participants, as the benefit may be determined by polymorphisms in an individual's genetic background.
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Affiliation(s)
- Huiling Li
- a Department of Ophthalmology, The Second Xiangya Hospital , Central South University , Changsha , China
| | - Sumana R Chintalapudi
- b Department of Ophthalmology, The Hamilton Eye Institute , The University of Tennessee Health Science Center , Memphis , TN , USA.,c Department of Anatomy and Neurobiology , The University of Tennessee Health Science Center , Memphis , TN , USA
| | - Monica M Jablonski
- b Department of Ophthalmology, The Hamilton Eye Institute , The University of Tennessee Health Science Center , Memphis , TN , USA.,c Department of Anatomy and Neurobiology , The University of Tennessee Health Science Center , Memphis , TN , USA.,d Department of Pharmaceutical Sciences , The University of Tennessee Health Science Center , Memphis , TN , USA
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163
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O'Mealey GB, Plafker KS, Berry WL, Janknecht R, Chan JY, Plafker SM. A PGAM5-KEAP1-Nrf2 complex is required for stress-induced mitochondrial retrograde trafficking. J Cell Sci 2017; 130:3467-3480. [PMID: 28839075 DOI: 10.1242/jcs.203216] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 08/20/2017] [Indexed: 12/12/2022] Open
Abstract
The Nrf2 transcription factor is a master regulator of the cellular anti-stress response. A population of the transcription factor associates with the mitochondria through a complex with KEAP1 and the mitochondrial outer membrane histidine phosphatase, PGAM5. To determine the function of this mitochondrial complex, we knocked down each component and assessed mitochondrial morphology and distribution. We discovered that depletion of Nrf2 or PGAM5, but not KEAP1, inhibits mitochondrial retrograde trafficking induced by proteasome inhibition. Mechanistically, this disrupted motility results from aberrant degradation of Miro2, a mitochondrial GTPase that links mitochondria to microtubules. Rescue experiments demonstrate that this Miro2 degradation involves the KEAP1-cullin-3 E3 ubiquitin ligase and the proteasome. These data are consistent with a model in which an intact complex of PGAM5-KEAP1-Nrf2 preserves mitochondrial motility by suppressing dominant-negative KEAP1 activity. These data further provide a mechanistic explanation for how age-dependent declines in Nrf2 expression impact mitochondrial motility and induce functional deficits commonly linked to neurodegeneration.
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Affiliation(s)
- Gary B O'Mealey
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73118, USA.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73118, USA
| | - Kendra S Plafker
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73118, USA
| | - William L Berry
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73118, USA
| | - Ralf Janknecht
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73118, USA
| | - Jefferson Y Chan
- Department of Pathology, University of Irvine School of Medicine, Irvine, CA 92697, USA
| | - Scott M Plafker
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73118, USA
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164
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Humanin G (HNG) protects age-related macular degeneration (AMD) transmitochondrial ARPE-19 cybrids from mitochondrial and cellular damage. Cell Death Dis 2017; 8:e2951. [PMID: 28726777 PMCID: PMC5550888 DOI: 10.1038/cddis.2017.348] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 06/20/2017] [Accepted: 06/22/2017] [Indexed: 12/16/2022]
Abstract
Age-related macular degeneration (AMD) ranks third among the leading causes of visual impairment with a blindness prevalence rate of 8.7%. Despite several treatment regimens, such as anti-angiogenic drugs, laser therapy, and vitamin supplementation, being available for wet AMD, to date there are no FDA-approved therapies for dry AMD. Substantial evidence implicates mitochondrial damage and retinal pigment epithelium (RPE) cell death in the pathogenesis of AMD. However, the effects of AMD mitochondria and Humanin G (HNG), a more potent variant of the mitochondrial-derived peptide (MDP) Humanin, on retinal cell survival have not been elucidated. In this study, we characterized mitochondrial and cellular damage in transmitochondrial cybrid cell lines that contain identical nuclei but possess mitochondria from either AMD or age-matched normal (Older-normal (NL)) subjects. AMD cybrids showed (1) reduced levels of cell viability, lower mtDNA copy numbers, and downregulation of mitochondrial replication/transcription genes and antioxidant enzyme genes; and (2) elevated levels of genes related to apoptosis, autophagy and ER-stress along with increased mtDNA fragmentation and higher susceptibility to amyloid-β-induced toxicity compared to NL cybrids. In AMD cybrids, HNG protected the AMD mitochondria, reduced pro-apoptosis gene and protein levels, upregulated gp130 (a component of the HN receptor complex), and increased the protection against amyloid-β-induced damage. In summary, in cybrids, damaged AMD mitochondria mediate cell death that can be reversed by HNG treatment. Our results also provide evidence of Humanin playing a pivotal role in protecting cells with AMD mitochondria. In the future, it may be possible that AMD patient's blood samples containing damaged mitochondria may be useful as biomarkers for this condition. In conclusion, HNG may be a potential therapeutic target for treatment of dry AMD, a debilitating eye disease that currently has no available treatment. Further studies are needed to establish HNG as a viable mitochondria-targeting therapy for dry AMD.
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165
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Ferrington DA, Ebeling MC, Kapphahn RJ, Terluk MR, Fisher CR, Polanco JR, Roehrich H, Leary MM, Geng Z, Dutton JR, Montezuma SR. Altered bioenergetics and enhanced resistance to oxidative stress in human retinal pigment epithelial cells from donors with age-related macular degeneration. Redox Biol 2017; 13:255-265. [PMID: 28600982 PMCID: PMC5466586 DOI: 10.1016/j.redox.2017.05.015] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 05/23/2017] [Indexed: 01/03/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness among older adults. It has been suggested that mitochondrial defects in the retinal pigment epithelium (RPE) underlies AMD pathology. To test this idea, we developed primary cultures of RPE to ask whether RPE from donors with AMD differ in their metabolic profile compared with healthy age-matched donors. Analysis of gene expression, protein content, and RPE function showed that these cultured cells replicated many of the cardinal features of RPE in vivo. Using the Seahorse Extracellular Flux Analyzer to measure bioenergetics, we observed RPE from donors with AMD exhibited reduced mitochondrial and glycolytic function compared with healthy donors. RPE from AMD donors were also more resistant to oxidative inactivation of these two energy-producing pathways and were less susceptible to oxidation-induced cell death compared with cells from healthy donors. Investigation of the potential mechanism responsible for differences in bioenergetics and resistance to oxidative stress showed RPE from AMD donors had increased PGC1α protein as well as differential expression of multiple genes in response to an oxidative challenge. Based on our data, we propose that cultured RPE from donors phenotyped for the presence or absence of AMD provides an excellent model system for studying "AMD in a dish". Our results are consistent with the ideas that (i) a bioenergetics crisis in the RPE contributes to AMD pathology, and (ii) the diseased environment in vivo causes changes in the cellular profile that are retained in vitro.
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Affiliation(s)
- Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA,Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA,Corresponding author at: 380 Lions Research Bldg., 2001 6th St. SE, Minneapolis, MN 55455, USA.
| | - Mara C. Ebeling
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Marcia R. Terluk
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cody R. Fisher
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA,Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jorge R. Polanco
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Heidi Roehrich
- Histology Core for Vision Research, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Michaela M. Leary
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Zhaohui Geng
- Stem Cell Institute and Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA.
| | - James R. Dutton
- Stem Cell Institute and Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sandra R. Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
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166
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Kamel K, Farrell M, O'Brien C. Mitochondrial dysfunction in ocular disease: Focus on glaucoma. Mitochondrion 2017; 35:44-53. [PMID: 28499981 DOI: 10.1016/j.mito.2017.05.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/08/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Mitochondrial dysfunction commonly presents with ocular findings as a part of a systemic disorder. These ophthalmic manifestations can be the first sign of a mitochondrial abnormality, which highlights the key role of a comprehensive ophthalmic assessment. On the other hand, a number of visually disabling genetic and acquired eye diseases with no curative treatment show abnormal mitochondrial function. Recent advances in mitochondrial research have improved our understanding of previously unexplained ocular disorders utilising better diagnostic approaches. Further studies on mitochondrial dysfunction and novel modalities of treatment will help to improve outcomes of these conditions. In this review article we discuss the clinical picture of common mitochondrial-related eye diseases, diagnostic approaches and possible treatment options including a very recent interesting report about gene therapy, with a particular focus on glaucoma.
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Affiliation(s)
- Khalid Kamel
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | | | - Colm O'Brien
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland.
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167
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Jones MK, Lu B, Girman S, Wang S. Cell-based therapeutic strategies for replacement and preservation in retinal degenerative diseases. Prog Retin Eye Res 2017; 58:1-27. [PMID: 28111323 PMCID: PMC5441967 DOI: 10.1016/j.preteyeres.2017.01.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 01/08/2017] [Accepted: 01/17/2017] [Indexed: 12/13/2022]
Abstract
Cell-based therapeutics offer diverse options for treating retinal degenerative diseases, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). AMD is characterized by both genetic and environmental risks factors, whereas RP is mainly a monogenic disorder. Though treatments exist for some patients with neovascular AMD, a majority of retinal degenerative patients have no effective therapeutics, thus indicating a need for universal therapies to target diverse patient populations. Two main cell-based mechanistic approaches are being tested in clinical trials. Replacement therapies utilize cell-derived retinal pigment epithelial (RPE) cells to supplant lost or defective host RPE cells. These cells are similar in morphology and function to native RPE cells and can potentially supplant the responsibilities of RPE in vivo. Preservation therapies utilize supportive cells to aid in visual function and photoreceptor preservation partially by neurotrophic mechanisms. The goal of preservation strategies is to halt or slow the progression of disease and maintain remaining visual function. A number of clinical trials are testing the safety of replacement and preservation cell therapies in patients; however, measures of efficacy will need to be further evaluated. In addition, a number of prevailing concerns with regards to the immune-related response, longevity, and functionality of the grafted cells will need to be addressed in future trials. This review will summarize the current status of cell-based preclinical and clinical studies with a focus on replacement and preservation strategies and the obstacles that remain regarding these types of treatments.
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Affiliation(s)
- Melissa K Jones
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
| | - Bin Lu
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
| | - Sergey Girman
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
| | - Shaomei Wang
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA; David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave., Los Angeles, CA 90095, USA.
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168
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Mitochondrial dysfunction underlying outer retinal diseases. Mitochondrion 2017; 36:66-76. [PMID: 28365408 DOI: 10.1016/j.mito.2017.03.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 03/06/2017] [Accepted: 03/27/2017] [Indexed: 01/21/2023]
Abstract
Dysfunction of photoreceptors, retinal pigment epithelium (RPE) or both contribute to the initiation and progression of several outer retinal disorders. Disrupted Müller glia function might additionally subsidize to these diseases. Mitochondrial malfunctioning is importantly associated with outer retina pathologies, which can be classified as primary and secondary mitochondrial disorders. This review highlights the importance of oxidative stress and mitochondrial DNA damage, underlying outer retinal disorders. Indeed, the metabolically active photoreceptors/RPE are highly prone to these hallmarks of mitochondrial dysfunction, indicating that mitochondria represent a weak link in the antioxidant defenses of outer retinal cells.
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169
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The impact of oxidative stress and inflammation on RPE degeneration in non-neovascular AMD. Prog Retin Eye Res 2017; 60:201-218. [PMID: 28336424 DOI: 10.1016/j.preteyeres.2017.03.002] [Citation(s) in RCA: 478] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 02/07/2023]
Abstract
The retinal pigment epithelium (RPE) is a highly specialized, unique epithelial cell that interacts with photoreceptors on its apical side and with Bruch's membrane and the choriocapillaris on its basal side. Due to vital functions that keep photoreceptors healthy, the RPE is essential for maintaining vision. With aging and the accumulated effects of environmental stresses, the RPE can become dysfunctional and die. This degeneration plays a central role in age-related macular degeneration (AMD) pathobiology, the leading cause of blindness among the elderly in western societies. Oxidative stress and inflammation have both physiological and potentially pathological roles in RPE degeneration. Given the central role of the RPE, this review will focus on the impact of oxidative stress and inflammation on the RPE with AMD pathobiology. Physiological sources of oxidative stress as well as unique sources from photo-oxidative stress, the phagocytosis of photoreceptor outer segments, and modifiable factors such as cigarette smoking and high fat diet ingestion that can convert oxidative stress into a pathological role, and the negative impact of impairing the cytoprotective roles of mitochondrial dynamics and the Nrf2 signaling system on RPE health in AMD will be discussed. Likewise, the response by the innate immune system to an inciting trigger, and the potential role of local RPE production of inflammation, as well as a potential role for damage by inflammation with chronicity if the inciting trigger is not neutralized, will be debated.
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170
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Riazi-Esfahani M, Kuppermann BD, Kenney MC. The Role of Mitochondria in AMD: Current Knowledge and Future Applications. J Ophthalmic Vis Res 2017; 12:424-428. [PMID: 29090054 PMCID: PMC5644411 DOI: 10.4103/jovr.jovr_182_17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mitochondria are organelles which comprise the main respiratory machinery in the eukaryotic cells. In addition to their crucial role in energy production, they have profound effects on apoptosis and retrograde signaling to nucleus. Mitochondria have their own DNA, which codes for different proteins mostly involved in oxidative phosphorylation. Significant changes in the mitochondria of retinal pigment epithelium have been reported in age-related macular degeneration (AMD), which is correlated with the severity of the disease. Cybrid cell lines that have identical nuclei but mitochondria from different individuals can provide a unique means for studying the relationship between mitochondria and AMD. Different approaches for protection of mitochondria have been introduced which can be considered as potential future treatments for AMD and other age- related disorders.
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Affiliation(s)
- Mohammad Riazi-Esfahani
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA.,Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Baruch D Kuppermann
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA.,Department of Biomedical Engineering, University of California Irvine, Irvine, California, USA
| | - M Cristina Kenney
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA.,Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, USA
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171
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Miller JW, Bagheri S, Vavvas DG. Advances in Age-related Macular Degeneration Understanding and Therapy. ACTA ACUST UNITED AC 2017; 10:119-130. [PMID: 29142592 PMCID: PMC5683729 DOI: 10.17925/usor.2017.10.02.119] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
While the development of anti-vascular endothelial growth factor (anti-VEGF) as a therapy for neovascular age-related macular degeneration (AMD) was a great success, the pathologic processes underlying dry AMD that eventually leads to photoreceptor dysfunction, death, and vision loss remain elusive to date, with a lack of effective therapies and increasing prevalence of the disease. There is an overwhelming need to improve the classification system of AMD, to increase our understanding of cell death mechanisms involved in both neovascular and non-neovascular AMD, and to develop better biomarkers and clinical endpoints to eventually be able to identify better therapeutic targets—especially early in the disease process. There is no doubt that it is a matter of time before progress will be made and better therapies will be developed for non-neovascular AMD.
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Affiliation(s)
- Joan W Miller
- Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, US
| | - Saghar Bagheri
- Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, US
| | - Demetrios G Vavvas
- Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, US
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172
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Bakeeva LE. Age-Related Changes in Ultrastructure of Mitochondria. Effect of SkQ1. BIOCHEMISTRY (MOSCOW) 2016; 80:1582-8. [PMID: 26638683 DOI: 10.1134/s0006297915120068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
For many years, investigators have attempted to identify unique ultrastructural conditions of mitochondria related to aging. However, this did not result in definitive results. At present, this issue has again become of topical interest due to development of the mitochondrial theory of aging and of engineering of a novel antioxidant class known as mitochondria-targeted antioxidants. The review briefly discusses experimental results that, from our perspective, allow the most objective understanding regarding age-related changes in mitochondrial ultrastructure.
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Affiliation(s)
- L E Bakeeva
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119991, Russia.
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173
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Melatonin in Retinal Physiology and Pathology: The Case of Age-Related Macular Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6819736. [PMID: 27688828 PMCID: PMC5027321 DOI: 10.1155/2016/6819736] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/09/2016] [Indexed: 12/16/2022]
Abstract
Melatonin, an indoleamine, is synthesized mainly in the pineal gland in a circadian fashion, but it is produced in many other organs, including the retina, which seems to be especially important as the eye is a primary recipient of circadian signals. Melatonin displays strong antioxidative properties, which predispose it to play a protective role in many human pathologies associated with oxidative stress, including premature aging and degenerative disease. Therefore, melatonin may play a role in age-related macular degeneration (AMD), a disease affecting photoreceptors, and retinal pigment epithelium (RPE) with an established role of oxidative stress in its pathogenesis. Several studies have shown that melatonin could exert the protective effect against damage to RPE cells evoked by reactive oxygen species (ROS), but it has also been reported to increase ROS-induced damage to photoreceptors and RPE. Melatonin behaves like synthetic mitochondria-targeted antioxidants, which concentrate in mitochondria at relatively high levels; thus, melatonin may prevent mitochondrial damage in AMD. The retina contains telomerase, an enzyme implicated in maintaining the length of telomeres, and oxidative stress inhibits telomere synthesis, while melatonin overcomes this effect. These features support considering melatonin as a preventive and therapeutic agent in the treatment of AMD.
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174
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Nashine S, Chwa M, Kazemian M, Thaker K, Lu S, Nesburn A, Kuppermann BD, Kenney MC. Differential Expression of Complement Markers in Normal and AMD Transmitochondrial Cybrids. PLoS One 2016; 11:e0159828. [PMID: 27486856 PMCID: PMC4972370 DOI: 10.1371/journal.pone.0159828] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 07/09/2016] [Indexed: 12/19/2022] Open
Abstract
Purpose Variations in mitochondrial DNA (mtDNA) and abnormalities in the complement pathways have been implicated in the pathogenesis of age-related macular degeneration (AMD). This study was designed to determine the effects of mtDNA from AMD subjects on the complement pathway. Methods Transmitochondrial cybrids were prepared by fusing platelets from AMD and age-matched Normal subjects with Rho0 (lacking mtDNA) human ARPE-19 cells. Quantitative PCR and Western blotting were performed to examine gene and protein expression profiles, respectively, of complement markers in these cybrids. Bioenergetic profiles of Normal and AMD cybrids were examined using the Seahorse XF24 flux analyzer. Results Significant decreases in the gene and protein expression of complement inhibitors, along with significantly higher levels of complement activators, were found in AMD cybrids compared to Older-Normal cybrids. Seahorse flux data demonstrated that the bioenergetic profiles for Older-Normal and Older-AMD cybrid samples were similar to each other but were lower compared to Young-Normal cybrid samples. Conclusion In summary, since all cybrids had identical nuclei and differed only in mtDNA content, the observed changes in components of complement pathways can be attributed to mtDNA variations in the AMD subjects, suggesting that mitochondrial genome and retrograde signaling play critical roles in this disease. Furthermore, the similar bioenergetic profiles of AMD and Older-Normal cybrids indicate that the signaling between mitochondria and nuclei are probably not via a respiratory pathway.
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Affiliation(s)
- Sonali Nashine
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - Marilyn Chwa
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - Mina Kazemian
- College of Osteopathic Medicine, Touro University Nevada, Nevada, United States of America
| | - Kunal Thaker
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - Stephanie Lu
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
- VA Medical Center Long Beach Hospital, Long Beach, California, United States of America
| | - Anthony Nesburn
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
- Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Baruch D. Kuppermann
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - M. Cristina Kenney
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, California, United States of America
- * E-mail:
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175
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Perepechaeva ML, Kolosova NG, Stefanova NA, Fursova AZ, Grishanova AY. The influence of changes in expression of redox-sensitive genes on the development of retinopathy in rats. Exp Mol Pathol 2016; 101:124-32. [PMID: 27466007 DOI: 10.1016/j.yexmp.2016.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 06/07/2016] [Accepted: 07/19/2016] [Indexed: 01/24/2023]
Abstract
Age-related macular degeneration (AMD) is a complex multifactorial disease of the elderly, with unclear pathogenesis; AMD is the leading cause of blindness. One of the destructive processes in AMD is oxidative stress, which leads to an imbalance in the processes responsible for production and detoxification of reactive oxygen species. The aryl hydrocarbon receptor (AhR) signaling pathway can participate in the development of oxidative stress, but the main regulator of antioxidant defense is nuclear factor, erythroid derived 2 (Nrf2). AhR-dependent oxidative stress can be attenuated by activation of Nrf2, and defects in the Nrf2 signaling pathway can increase sensitivity of the cell to oxidative stress. Our aim was to determine the role of the pro-oxidant (AhR-dependent) and antioxidant (Nrf2-dependent) systems in the pathogenesis of AMD using rats of OXYS strain and of OXYSb substrain with signs of AMD-like retinopathy of varying severity. We compared the retinal levels of mRNA expression of Nrf2- and AhR-dependent redox-sensitive systems between 1-, 3-, and 12- month-old senescence-accelerated OXYS rats (have been shown to be a valid experimental model of AMD) and the rat substrain OXYSb, which shows low morbidity of AMD. We uncovered interstrain differences in the expression of Nrf2 and Nrf2-dependent genes (glutathione S-reductase [Gsr] and heme oxygenase 1 [Hmox1]), in the expression of AhR-dependent genes (cytochrome P450 1A2 [Cyp1a2] and cytochrome P450 1B1 [Cyp1b1]), and in the NADPH-quinone oxidoreductase (Nqo1) expression, which is controlled by both AhR and Nrf2. Binding of AhR and Nrf2 proteins to the regulatory regions of AhR and Nrf2 genes, respectively, was detected by chromatin immunoprecipitation in the retina of 1-, 3-, and 12-month-old OXYS, OXYSb, and Wistar (control) rats. We compared the strength of DNA-protein interactions of AhR and Nrf2 with regulatory sequences and found that the level of autoupregulation of the AhR gene was higher in the retina of 1-month-old OXYSb rats in comparison with OXYS rats. An imbalance between pro-oxidant (AhR-dependent) and antioxidant (Nrf2-dependent) systems may play a crucial role in the onset and/or progression of AMD.
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Affiliation(s)
- M L Perepechaeva
- Institute of Molecular Biology and Biophysics, Timakova Str. 2/12, Novosibirsk 630117, Russia.
| | - N G Kolosova
- Institute of Molecular Biology and Biophysics, Timakova Str. 2/12, Novosibirsk 630117, Russia; Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Lavrentiev Ave. 10, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia.
| | - N A Stefanova
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Lavrentiev Ave. 10, Novosibirsk 630090, Russia.
| | - A Zh Fursova
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Lavrentiev Ave. 10, Novosibirsk 630090, Russia.
| | - A Y Grishanova
- Institute of Molecular Biology and Biophysics, Timakova Str. 2/12, Novosibirsk 630117, Russia.
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176
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Mohanty K, Dada R, Dada T. Neurodegenerative Eye Disorders: Role of Mitochondrial Dynamics and Genomics. Asia Pac J Ophthalmol (Phila) 2016; 5:293-9. [PMID: 27101384 DOI: 10.1097/apo.0000000000000203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
As a major source of cellular energy, mitochondria are critical for optimal ocular function. They are also essential for cell differentiation and survival. Mitochondrial mutations and oxidative damage to the mitochondrial DNA are important factors underlying the pathology of many ocular disorders. With increasing age, mitochondrial DNA damage accumulates and results in several eye diseases. It is evident that the mitochondrial genome is more susceptible to stress and damage than the nuclear genome, as it lacks histone protection, a nucleotide excision repair system, and recombination repair, and it is the source and target of free radicals. Accumulation of mitochondrial mutations beyond a certain threshold explains the marked variations in phenotypes seen in mitochondrial diseases and the molecular mechanisms related to the pathogenesis of several chronic disorders in the eye. This review details the structure and function of mitochondria and the mitochondrial genome along with the mitochondrial involvement in various neurodegenerative ophthalmic disorders.
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Affiliation(s)
- Kuldeep Mohanty
- From the *Department of Ophthalmology, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India; and †Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, AIIMS, New Delhi, India
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177
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Gouras P, Ivert L, Neuringer M, Nagasaki T. Mitochondrial elongation in the macular RPE of aging monkeys, evidence of metabolic stress. Graefes Arch Clin Exp Ophthalmol 2016; 254:1221-7. [PMID: 27106622 DOI: 10.1007/s00417-016-3342-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 03/29/2016] [Accepted: 04/04/2016] [Indexed: 12/11/2022] Open
Abstract
PURPOSE This study was conducted to determine whether mitochondria of the macular retinal pigment epithelium (RPE) change with age in rhesus monkeys (Macaca mulatta). Mitochondria are the main instigators of oxidative stress, which has often been considered to play a role in the pathogenesis of age-related macular degeneration (AMD). Any pathological changes in the mitochondria of aging macular RPE, the main target of AMD, would be a clue to the pathogenesis of this common retinal degeneration afflicting both monkey and man. METHODS Transmission electron microscopy was used to identify mitochondria and to determine their appearance, their density per unit area of RPE cytoplasm and their length. The eyes of seven monkeys, 1, 2, 6.5, 23, 26, 27 and 35 years of age, were studied. Measurements were kept separate for the basal, middle and apical third of each cell. The basal third of the macular RPE had many more mitochondria than the middle third, and the apical third was almost devoid of mitochondria. RESULTS Mitochondrial number decreased and length increased with age. The increase in length was associated with an unusual clustering of mitochondria into parallel arrays of elongated mitochondria, with their long axis orthogonal to the basal membrane of the cell, structures not described before in RPE. CONCLUSIONS Mitochondrial elongation is associated with metabolic and/or oxidative stress, which implies that age produces stress in macular RPE. The increased clustering of very elongated mitochondria suggests that pathological changes occur in mitochondrial organization with age. These changes support the hypothesis that age-related mitochondrial dysfunction plays a role in the pathogenesis of AMD.
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Affiliation(s)
- Peter Gouras
- Department of Ophthalmology, Columbia University, New York City, NY, USA. .,Edward S. Harkness Eye Institute, Research Annex, 635 West 165th Street, Box #76, New York, NY, 10032, USA.
| | - L Ivert
- St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden
| | - M Neuringer
- Oregon Health & Science University, Portland, OR, USA
| | - T Nagasaki
- Department of Ophthalmology, Columbia University, New York City, NY, USA
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178
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Oxidative Stress and the Nrf2 Anti-Oxidant Transcription Factor in Age-Related Macular Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:67-72. [PMID: 26427395 DOI: 10.1007/978-3-319-17121-0_10] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of acquired and irreversible blindness among elderly Americans. Most AMD patients have the dry form of the disease (dAMD) for which reliable therapies are lacking. A major obstacle to the development of effective treatments is a deficit in our understanding of what triggers dAMD onset. This is particularly the case with respect to the events that cause retinal pigment epithelial (RPE) cells to transition from a state of health and homeostasis to one of dysfunction and atrophy. These cells provide critical support to the photoreceptors and their atrophy often precipitates photoreceptor death in dAMD. Chronic oxidative stress is a primary driver of age-dependent, RPE atrophy. Sources of this stress have been identified (e.g., cigarette smoke, photooxidized bisretinoids), but we still do not understand how these stressors damage RPE constituents or what age-dependent changes undermine the cytoprotective systems in the RPE. This review focuses on Nrf2, the master antioxidant transcription factor, and its role in the RPE during aging and dAMD onset.
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179
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Ferrington DA, Kapphahn RJ, Leary MM, Atilano SR, Terluk MR, Karunadharma P, Chen GKJ, Ratnapriya R, Swaroop A, Montezuma SR, Kenney MC. Increased retinal mtDNA damage in the CFH variant associated with age-related macular degeneration. Exp Eye Res 2016; 145:269-277. [PMID: 26854823 DOI: 10.1016/j.exer.2016.01.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/25/2016] [Accepted: 01/29/2016] [Indexed: 11/17/2022]
Abstract
Age-related macular degeneration (AMD) is a major cause of blindness among the elderly in the developed world. Genetic analysis of AMD has identified 34 high-risk loci associated with AMD. The genes at these high risk loci belong to diverse biological pathways, suggesting different mechanisms leading to AMD pathogenesis. Thus, therapies targeting a single pathway for all AMD patients will likely not be universally effective. Recent evidence suggests defects in mitochondria (mt) of the retinal pigment epithelium (RPE) may constitute a key pathogenic event in some AMD patients. The purpose of this study is to determine if individuals with a specific genetic background have a greater propensity for mtDNA damage. We used human eyebank tissues from 76 donors with AMD and 42 age-matched controls to determine the extent of mtDNA damage in the RPE that was harvested from the macula using a long extension polymerase chain reaction assay. Genotype analyses were performed for ten common AMD-associated nuclear risk alleles (ARMS2, TNFRSF10A, CFH, C2, C3, APOE, CETP, LIPC, VEGF and COL10A1) and mtDNA haplogroups. Sufficient samples were available for genotype association with mtDNA damage for TNFRSF10A, CFH, CETP, VEGFA, and COL10A1. Our results show that AMD donors carrying the high risk allele for CFH (C) had significantly more mtDNA damage compared with donors having the wild-type genetic profile. The data from an additional 39 donors (12 controls and 27 AMD) genotyped for CFH alleles further supported these findings. Taken together, these studies provide the rationale for a more personalized approach for treating AMD by uncovering a significant correlation between the CFH high risk allele and accelerated mtDNA damage. Patients harboring this genetic risk factor may benefit from therapies that stabilize and protect the mt in the RPE.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Rebecca J Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Michaela M Leary
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Shari R Atilano
- Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
| | - Marcia R Terluk
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Pabalu Karunadharma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | | | - Rinki Ratnapriya
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, Bethesda, MD 20892, USA
| | - Sandra R Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - M Cristina Kenney
- Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
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180
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Abstract
INTRODUCTION Mitochondria, essential to multicellular life, convert food into ATP to satisfy cellular energy demands. Since different tissues have different energy requirements, mitochondrial density is high in tissues with high metabolic needs, such as the visual system, which is therefore highly susceptible to limited energy supply as a result of mitochondrial dysfunction. AREAS COVERED Vision impairment is a common feature of most mitochondrial diseases. At the same time, there is mounting evidence that mitochondrial impairment contributes to the pathogenesis of major eye diseases such as glaucoma and might also be involved in the reported vision impairment in neurodegenerative disorders such as Alzheimer's disease. EXPERT OPINION Rather than relying on symptomatic treatment, acknowledging the mitochondrial origin of visual disorders in mitochondrial, neurodegenerative and ocular diseases could lead to novel therapeutics that aim to modulate mitochondrial function in order to protect against vision loss. This approach has already shown some promising clinical results in inherited retinal disorders, which supports the idea that targeting mitochondria could also be a treatment option for other optic neuropathies.
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Affiliation(s)
- Jamuna Chhetri
- a Division of Pharmacy, School of Medicine, Faculty of Health , University of Tasmania , Hobart , Australia
| | - Nuri Gueven
- a Division of Pharmacy, School of Medicine, Faculty of Health , University of Tasmania , Hobart , Australia
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181
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Tao Y, Jiang P, Wei Y, Wang P, Sun X, Wang H. α-Lipoic Acid Treatment Improves Vision-Related Quality of Life in Patients with Dry Age-Related Macular Degeneration. TOHOKU J EXP MED 2016; 240:209-214. [DOI: 10.1620/tjem.240.209] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Yuan Tao
- Department of Opthalmology, the Second People’s Hospital of Jinan City
| | - Pengfei Jiang
- Department of Opthalmology, Yantai Yuhuangding Hospital
| | - Yuhua Wei
- Department of Medicine, Qilu Hospital of Shandong University
| | - Ping Wang
- Department of Surgery, Qilu Hospital of Shandong University
| | - Xiaoling Sun
- Department of Surgery, Yantai Yuhuangding Hospital
| | - Hong Wang
- Department of Opthalmology, Qilu Hospital of Shandong University
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182
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Dib B, Lin H, Maidana DE, Tian B, Miller JB, Bouzika P, Miller JW, Vavvas DG. Mitochondrial DNA has a pro-inflammatory role in AMD. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:2897-906. [PMID: 26305120 PMCID: PMC5330253 DOI: 10.1016/j.bbamcr.2015.08.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 08/10/2015] [Accepted: 08/20/2015] [Indexed: 12/13/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly of industrialized nations, and there is increasing evidence to support a role for chronic inflammation in its pathogenesis. Mitochondrial DNA (mtDNA) has been recently reported to be pro-inflammatory in various diseases such as Alzheimer's and heart failure. Here, we report that intracellular mtDNA induces ARPE-19 cells to secrete inflammatory cytokines IL-6 and IL-8, which have been consistently associated with AMD onset and progression. The induction was dependent on the size of mtDNA, but not on specific sequence. Oxidative stress plays a major role in the development of AMD, and our findings indicate that mtDNA induces IL-6 and IL-8 more potently when oxidized. Cytokine induction was mediated by STING (Stimulator of Interferon Genes) and NF-κB as evidenced by abrogation of the cytokine response with the use of specific inhibitors (siRNA and BAY 11-7082, respectively). Finally, mtDNA primed the NLRP3 inflammasome. This study contributes to our understanding of the potential pro-inflammatory role of mtDNA in the pathogenesis of AMD.
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Affiliation(s)
- Bernard Dib
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - Haijiang Lin
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - Daniel E Maidana
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - Bo Tian
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - John B Miller
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - Peggy Bouzika
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - Joan W Miller
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - Demetrios G Vavvas
- Retina Service, Angiogenesis Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States.
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183
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Ach T, Tolstik E, Messinger JD, Zarubina AV, Heintzmann R, Curcio CA. Lipofuscin redistribution and loss accompanied by cytoskeletal stress in retinal pigment epithelium of eyes with age-related macular degeneration. Invest Ophthalmol Vis Sci 2015; 56:3242-52. [PMID: 25758814 DOI: 10.1167/iovs.14-16274] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Lipofuscin (LF) and melanolipofuscin (MLF) of the retinal pigment epithelium (RPE) are the principal sources of autofluorescence (AF) signals in clinical fundus-AF imaging. Few details about the subcellular distribution of AF organelles in AMD are available. We describe the impact of aging and AMD on RPE morphology revealed by the distribution of AF LF/MLF granules and actin cytoskeleton in human tissues. METHODS Thirty-five RPE-Bruch's membrane flatmounts from 35 donors were prepared (postmortem: ≤4 hours). Ex vivo fundus examination at the time of accession revealed either absence of chorioretinal pathologies (10 tissues; mean age: 83.0 ± 2.6 years) or stages of AMD (25 tissues; 85.0 ± 5.8 years): early AMD, geographic atrophy, and late exudative AMD. Retinal pigment epithelium cytoskeleton was labeled with AlexaFluor647-Phalloidin. Tissues were imaged on a spinning-disk fluorescence microscope and a high-resolution structured illumination microscope. RESULTS Age-related macular degeneration impacts individual RPE cells by (1) lipofuscin redistribution by (i) degranulation (granule-by-granule loss) and/or (ii) aggregation and apparent shedding into the extracellular space; (2) enlarged RPE cell area and conversion from convex to irregular and sometimes concave polygons; and (3) cytoskeleton derangement including separations and breaks around subretinal deposits, thickening, and stress fibers. CONCLUSIONS We report an extensive and systematic en face analysis of LF/MLF-AF in AMD eyes. Redistribution and loss of AF granules are among the earliest AMD changes and could reduce fundus AF signal attributable to RPE at these locations. Data can enhance the interpretation of clinical fundus-AF and provide a basis for future quantitative studies.
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Affiliation(s)
- Thomas Ach
- University of Alabama at Birmingham Department of Ophthalmology, Birmingham, Alabama, United States 2University Hospital Würzburg, Department of Ophthalmology, Würzburg, Germany
| | - Elen Tolstik
- Leibniz Institute of Photonic Technology, Jena, Germany 5King's College London, Randall Division of Cell & Molecular Biophysics, London, United Kingdom
| | - Jeffrey D Messinger
- University of Alabama at Birmingham Department of Ophthalmology, Birmingham, Alabama, United States
| | - Anna V Zarubina
- University of Alabama at Birmingham Department of Ophthalmology, Birmingham, Alabama, United States
| | - Rainer Heintzmann
- Leibniz Institute of Photonic Technology, Jena, Germany 5King's College London, Randall Division of Cell & Molecular Biophysics, London, United Kingdom
| | - Christine A Curcio
- University of Alabama at Birmingham Department of Ophthalmology, Birmingham, Alabama, United States
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184
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Zanzottera EC, Messinger JD, Ach T, Smith RT, Freund KB, Curcio CA. The Project MACULA Retinal Pigment Epithelium Grading System for Histology and Optical Coherence Tomography in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2015; 56:3253-68. [PMID: 25813989 DOI: 10.1167/iovs.15-16431] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PURPOSE To seek pathways of retinal pigment epithelium (RPE) fate in age-related macular degeneration via a morphology grading system; provide nomenclature, visualization targets, and metrics for clinical imaging and model systems. METHODS Donor eyes with geographic atrophy (GA) or choroidal neovascularization (CNV) and one GA eye with previous clinical spectral-domain optical coherence tomography (SDOCT) imaging were processed for histology, photodocumented, and annotated at predefined locations. Retinal pigment epithelial cells contained spindle-shaped melanosomes, apposed a basal lamina or basal laminar deposit (BLamD), and exhibited recognizable morphologies. Thicknesses and unbiased estimates of frequencies were obtained. RESULTS In 13 GA eyes (449 locations), 'Shedding,' 'Sloughed,' and 'Dissociated' morphologies were abundant; 22.2% of atrophic locations had 'Dissociated' RPE. In 39 CNV eyes (1363 locations), 37.3% of locations with fibrovascular/fibrocellular scar had 'Entombed' RPE; 'Sloughed,' 'Dissociated,' and 'Bilaminar' morphologies were abundant. Of abnormal RPE, CNV and GA both had ~35% 'Sloughed'/'Intraretinal,' with more Intraretinal in CNV (9.5% vs. 1.8%). 'Shedding' cells associated with granule aggregations in BLamD. The RPE layer did not thin, and BLamD remained thick, with progression. Granule-containing material consistent with three morphologies correlated to SDOCT hyperreflective foci in the previously examined GA patient. CONCLUSIONS Retinal pigment epithelium morphology indicates multiple pathways in GA and CNV. Atrophic/scarred areas have numerous cells capable of transcribing genes and generating imaging signals. Shed granule aggregates, possibly apoptotic, are visible in SDOCT, as are 'Dissociated' and 'Sloughed' cells. The significance of RPE phenotypes is addressable in longitudinal, high-resolution imaging in clinic populations. Data can motivate future molecular phenotyping studies.
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Affiliation(s)
- Emma C Zanzottera
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States 2Eye Clinic, Department of Clinical Science "Luigi Sacco," Sacco Hospital, University of Milan, Milan, Italy
| | - Jeffrey D Messinger
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States
| | - Thomas Ach
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States 3University Hospital Würzburg, Department of Ophthalmology, Würzburg, Germany
| | - R Theodore Smith
- Department of Ophthalmology, New York University School of Medicine, New York City, New York, United States
| | - K Bailey Freund
- Department of Ophthalmology, New York University School of Medicine, New York City, New York, United States 5Vitreous Retina Macula Consultants of New York, New York, New York, United States 6LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear
| | - Christine A Curcio
- Department of Ophthalmology University of Alabama School of Medicine, Birmingham, Alabama, United States
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185
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Ferrington DA, Sinha D, Kaarniranta K. Defects in retinal pigment epithelial cell proteolysis and the pathology associated with age-related macular degeneration. Prog Retin Eye Res 2015; 51:69-89. [PMID: 26344735 DOI: 10.1016/j.preteyeres.2015.09.002] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 08/29/2015] [Accepted: 09/01/2015] [Indexed: 12/12/2022]
Abstract
Maintenance of protein homeostasis, also referred to as "Proteostasis", integrates multiple pathways that regulate protein synthesis, folding, translocation, and degradation. Failure in proteostasis may be one of the underlying mechanisms responsible for the cascade of events leading to age-related macular degeneration (AMD). This review covers the major degradative pathways (ubiquitin-proteasome and lysosomal involvement in phagocytosis and autophagy) in the retinal pigment epithelium (RPE) and summarizes evidence of their involvement in AMD. Degradation of damaged and misfolded proteins via the proteasome occurs in coordination with heat shock proteins. Evidence of increased content of proteasome and heat shock proteins in retinas from human donors with AMD is consistent with increased oxidative stress and extensive protein damage with AMD. Phagocytosis and autophagy share key molecules in phagosome maturation as well as degradation of their cargo following fusion with lysosomes. Phagocytosis and degradation of photoreceptor outer segments ensures functional integrity of the neural retina. Autophagy rids the cell of toxic protein aggregates and defective mitochondria. Evidence suggesting a decline in autophagic flux includes the accumulation of autophagic substrates and damaged mitochondria in RPE from AMD donors. An age-related decrease in lysosomal enzymatic activity inhibits autophagic clearance of outer segments, mitochondria, and protein aggregates, thereby accelerating the accumulation of lipofuscin. This cumulative damage over a person's lifetime tips the balance in RPE from a state of para-inflammation, which strives to restore cell homeostasis, to the chronic inflammation associated with AMD.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, 2001 6th St SE, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Debasish Sinha
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Room M035 Robert and Clarice Smith Bldg, 400 N Broadway, Baltimore, MD, 21287, USA.
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland and Kuopio University Hospital, P.O. Box 100, 70029 KYS, Finland.
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186
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Georgiannakis A, Burgoyne T, Lueck K, Futter C, Greenwood J, Moss SE. Retinal Pigment Epithelial Cells Mitigate the Effects of Complement Attack by Endocytosis of C5b-9. THE JOURNAL OF IMMUNOLOGY 2015; 195:3382-9. [PMID: 26324770 PMCID: PMC4574521 DOI: 10.4049/jimmunol.1500937] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/29/2015] [Indexed: 01/01/2023]
Abstract
Retinal pigment epithelial (RPE) cell death is a hallmark of age-related macular degeneration. The alternative pathway of complement activation is strongly implicated in RPE cell dysfunction and loss in age-related macular degeneration; therefore, it is critical that RPE cells use molecular strategies to mitigate the potentially harmful effects of complement attack. We show that the terminal complement complex C5b-9 assembles rapidly on the basal surface of cultured primary porcine RPE cells but disappears over 48 h without any discernable adverse effects on the cells. However, in the presence of the dynamin inhibitor dynasore, C5b-9 was almost completely retained at the cell surface, suggesting that, under normal circumstances, it is eliminated via the endocytic pathway. In support of this idea, we observed that C5b-9 colocalizes with the early endosome marker EEA1 and that, in the presence of protease inhibitors, it can be detected in lysosomes. Preventing the endocytosis of C5b-9 by RPE cells led to structural defects in mitochondrial morphology consistent with cell stress. We conclude that RPE cells use the endocytic pathway to prevent the accumulation of C5b-9 on the cell surface and that processing and destruction of C5b-9 by this route are essential for RPE cell survival.
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Affiliation(s)
- Apostolos Georgiannakis
- Department of Cell Biology, University College London Institute of Ophthalmology, London EC1V9EL, United Kingdom
| | - Tom Burgoyne
- Department of Cell Biology, University College London Institute of Ophthalmology, London EC1V9EL, United Kingdom
| | - Katharina Lueck
- Department of Cell Biology, University College London Institute of Ophthalmology, London EC1V9EL, United Kingdom
| | - Clare Futter
- Department of Cell Biology, University College London Institute of Ophthalmology, London EC1V9EL, United Kingdom
| | - John Greenwood
- Department of Cell Biology, University College London Institute of Ophthalmology, London EC1V9EL, United Kingdom
| | - Stephen E Moss
- Department of Cell Biology, University College London Institute of Ophthalmology, London EC1V9EL, United Kingdom
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187
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Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness among older adults in the developed world. Although the pathological mechanisms have not been definitively elucidated, evidence suggests a key role for mitochondrial (mt) dysfunction. The current study used our unique collection of human retinal samples graded for the donor's stage of AMD to address fundamental questions about mtDNA damage in the retina. To evaluate the distribution of mtDNA damage in the diseased retina, damage in the retinal pigment epithelium (RPE) and neural retina from individual donors were compared. To directly test a long-held belief that the macula is selectively damaged with AMD, RPE mtDNA damage was measured in the macula and peripheral sections from individual donors. Small segments of the entire mt genome were examined to determine whether specific regions are preferentially damaged. Our results show that mtDNA damage is limited to the RPE, equivalent mtDNA damage is found in the macular and peripheral RPE, and sites of damage are localized to regions of the mt genome that may impact mt function. These results provide a scientific basis for targeting the RPE mitochondria with therapies that protect and enhance mt function as a strategy for combating AMD.
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188
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Jentsch S, Schweitzer D, Schmidtke KU, Peters S, Dawczynski J, Bär KJ, Hammer M. Retinal fluorescence lifetime imaging ophthalmoscopy measures depend on the severity of Alzheimer's disease. Acta Ophthalmol 2015; 93:e241-7. [PMID: 25482990 DOI: 10.1111/aos.12609] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 10/25/2014] [Indexed: 11/27/2022]
Abstract
PURPOSE To determine alterations in the retina of patients with Alzheimer's disease (AD) by the newly developed technique of fluorescence lifetime imaging ophthalmoscopy (FLIO) in a pilot study. METHODS FLIO set-up uses a scanning laser ophthalmoscope (HRA2, Heidelberg Engineering, Germany), which was modified by the use of an excitation pulse laser BLD440 (Becker&Hickl, Berlin, Germany) and detection of fluorescence lifetime by time-correlated single photon counting (TCSPC; Becker&Hickl) in two spectral channels (channel 1: 490-560 nm, channel 2: 560-700 nm). Least square fit of three exponential functions was used for fluorescence decay analysis. That resulted in three fluorescent components with lifetimes τi , amplitudes αi and relative contributions Qi . 16 patients with AD (mean age 77.2 ± 7.0 years) were investigated. After regular ophthalmic investigation, FLIO examination and OCT examination were performed. Alzheimer-specific clinical data were collected (MMSE, cerebrospinal fluid (CSF) concentration of amyloid-β (1-42), total-tau and phosphorylated tau181 (p-tau181) protein). RESULTS The FLIO parameters of the second fluorescent component α2 and Q2 (channel 2) correlated significantly with MMSE score (Q2 , R = -0.757, p = 0.007; α2 , R = -0.618, p = 0.043) as well as p-tau181-protein concentration in CSF (Q2 , R = 0.919, p = 0.009; α2 , R = 0.881, p = 0.020) in patients with AD. OCT measurements of retinal nerve fibre layer thickness, optic disc excavation and macular thickness neither correlated with Alzheimer-specific CSF data nor MMSE score. CONCLUSIONS Unlike conventional techniques, such as OCT, the new technique of FLIO revealed changes in the retina of patients with AD in relation to Alzheimer-specific markers in this pilot study.
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Affiliation(s)
- Susanne Jentsch
- Department of Ophthalmology; University Hospital Jena; Jena Germany
| | | | | | - Sven Peters
- Department of Ophthalmology; University Hospital Jena; Jena Germany
| | - Jens Dawczynski
- Department of Ophthalmology; University Hospital Leipzig; Leipzig Germany
| | - Karl-Jürgen Bär
- Department of Psychiatry; University Hospital Jena; Jena Germany
| | - Martin Hammer
- Department of Ophthalmology; University Hospital Jena; Jena Germany
- Center for Medical Optics and Photonics; University of Jena; Jena Germany
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189
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Sun L, Jin Y, Dong L, Sui HJ, Sumi R, Jahan R, Hu D, Li Z. Coccomyxa Gloeobotrydiformis Improves Learning and Memory in Intrinsic Aging Rats. Int J Biol Sci 2015; 11:825-32. [PMID: 26078724 PMCID: PMC4466463 DOI: 10.7150/ijbs.10861] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 04/23/2015] [Indexed: 02/02/2023] Open
Abstract
Declining in learning and memory is one of the most common and prominent problems during the aging process. Neurotransmitter changes, oxidative stress, mitochondrial dysfunction and abnormal signal transduction were considered to participate in this process. In the present study, we examined the effects of Coccomyxa gloeobotrydiformis (CGD) on learning and memory ability of intrinsic aging rats. As a result, CGD treated (50 mg/kg·d or 100 mg/kg ·d for a duration of 8 weeks) 22-month-old male rats, which have shown significant improvement on learning and spatial memory ability compared with control, which was evidently revealed in both the hidden platform tasks and probe trials. The following immunohistochemistry and Western blot experiments suggested that CGD could increase the content of Ach and thereby improve the function of the cholinergic neurons in the hippocampus, and therefore also improving learning and memory ability of the aged rats by acting as an anti-inflammatory agent. The effects of CGD on learning and memory might also have an association with the ERK/CREB signalling. The results above suggest that the naturally made drug CGD may have several great benefit as a multi-target drug in the process of prevention and/or treatment of age-dependent cognitive decline and aging process.
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Affiliation(s)
- Luning Sun
- 1. Department of Pathophysiology, College of Basic Medical Science, China Medical University
| | - Ying Jin
- 2. Department of Pharmacology, Liaoning Medical University
| | - Liming Dong
- 3. Department of Urology, the Forth Affiliated Hospital, China Medical University
| | - Hai-Juan Sui
- 2. Department of Pharmacology, Liaoning Medical University
| | - Ryo Sumi
- 4. Tanaka Memorial Laboratory, Nikken Sohonsha Corporation
| | - Rabita Jahan
- 5. International Education School, China Medical University
| | - Dahai Hu
- 6. Department of Statistics and Finance, School of Management, University of Science and Technology of China
| | - Zhi Li
- 7. Department of Ethnopharmacology, School of Pharmaceutical Sciences, China Medical University
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190
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Wang Y, Zhang D, Liu Y, Wang D, Liu J, Ji B. The protective effects of berry-derived anthocyanins against visible light-induced damage in human retinal pigment epithelial cells. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2015; 95:936-944. [PMID: 24909670 DOI: 10.1002/jsfa.6765] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/29/2014] [Accepted: 05/29/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Studies have shown that anthocyanins (ACNs) in berries contribute to eye health. However, information on the relationship between the chemical structures and visual functions of ACNs is scarce. This study investigated the protection effects of ACNs with different structures against visible light-induced damage in human retinal pigment epithelial (RPE) cells. RESULTS Four ACNs with different aglycones, namely, pelargonidin-3-glucoside (Pg-3-glu), cyanidin-3-glucoside (Cy-3-glu), delphinidin-3-glucoside, and malvidin-3-glucoside (Mv-3-glu), were isolated from three berries (blueberry, blackberry and strawberry). Of these ACNs, Cy-3-glu exhibited the highest reactive oxygen species inhibitory capacity in RPE cells, with 40 µg mL(-1) Cy-3-glu showing a ROS clearance of 57.5% ± 4.2%. The expression of vascular endothelial growth factor levels were significantly (P < 0.05) down-regulated by Cy-3-glu and Mv-3-glu in a visible light-induced damage RPE cell model. Cy-3-glu and Pg-3-glu treatments significantly (P < 0.05) inhibited the increase in β-galactosidase during the RPE cell ageing caused by visible light exposure. CONCLUSION Our findings suggest that the biological properties of different ACNs significantly vary. Cy-3-glu, which contains an ortho hydroxyl group in its B ring, possibly exerts multiple protective effects (antioxidant, anti-angiogenic and anti-ageing) in RPE cells. Therefore, Cy-3-glu may prove useful as a prophylactic health food for the prevention of retinal diseases.
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Affiliation(s)
- Yong Wang
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, People's Republic of China
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191
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Dedania VS, Grob S, Zhang K, Bakri SJ. Pharmacogenomics of response to anti-VEGF therapy in exudative age-related macular degeneration. Retina 2015; 35:381-91. [PMID: 25635578 DOI: 10.1097/iae.0000000000000466] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine whether there is an association between response to intravitreal anti-vascular endothelial growth factor agents and genotype in patients with neovascular age-related macular degeneration. METHODS Analysis of the current literature evaluating pharmacogenetics of treatment response in patients with neovascular age-related macular degeneration. RESULTS Studies have demonstrated associations between various genotypes and response to intravitreal anti-vascular endothelial growth factor agents. Lower-risk genotypes of the CFH, ARMS2, HTRA1, and VEGF-A genes may be associated with improved visual outcomes. Additionally, frequency of injections may be associated with certain genotypes. CONCLUSION Genetic background may influence an individual's response to treatment of neovascular age-related macular degeneration. Further studies to investigate biologic pathways of neovascular age-related macular degeneration and gene products that are directly involved might lead to better understanding of contribution of various genes to treatment response.
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Affiliation(s)
- Vaidehi S Dedania
- *Department of Ophthalmology, Albany Medical Center, Lions Eye Institute, Albany, New York; †Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts; ‡Department of Ophthalmology, University of California, Shiley Eye Center, Institute for Genomic Medicine, La Jolla, California; and §Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
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192
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Yu B, Xu P, Zhao Z, Cai J, Sternberg P, Chen Y. Subcellular distribution and activity of mechanistic target of rapamycin in aged retinal pigment epithelium. Invest Ophthalmol Vis Sci 2014; 55:8638-50. [PMID: 25491300 DOI: 10.1167/iovs.14-14758] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Inhibiting mechanistic target of rapamycin (mTOR) by pharmacological or genetic approaches can extend lifespan in mammals. The kinase activity of mTOR is controlled by upstream regulatory proteins and its subcellular localization. The purpose of this study was to characterize age-related alterations and functional consequences of mTOR signaling in the postmitotic RPE cells. METHODS Activity of mTOR complex 1 (mTORC1) was monitored by measuring phosphorylation status of its downstream effector protein S6, in either cultured human RPE cells or RPE explants prepared from mice at different ages. Subcellular distribution of mTOR was investigated by immunofluorescent staining of RPE culture or flatmount. The signaling of mTORC1 was modulated by either overexpression of a small guanosine triphosphatase, Ras homolog enriched in brain (Rheb), or disruption of the Ragulator complex with small interference RNA targeting p18. The effects of mTOR pathway on degradation of phagocytosed photoreceptor outer segments (POS) were determined by measuring the turnover rate of rhodopsin. RESULTS Aged RPE cells had more lysosome-associated mTOR and had increased response to amino acid stimulation. The lysosome distribution was essential for mTORC1 function, as disruption of the Ragulator complex abolished mTORC1 activation by amino acids. Increased mTORC1 activity caused decreased rate of degradation of internalized POS in the RPE. CONCLUSIONS Aging changes the subcellular localization and function of mTOR in the RPE. Increased mTORC1 inhibits POS degradation and may further exacerbate lysosome dysfunction of aged RPE.
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Affiliation(s)
- Bo Yu
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Pei Xu
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Zhenyang Zhao
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Jiyang Cai
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
| | - Paul Sternberg
- Vanderbilt Eye Institute, Vanderbilt University, Nashville, Tennessee, United States
| | - Yan Chen
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, United States
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Kanan Y, Gordon WC, Mukherjee PK, Bazan NG, Al-Ubaidi MR. Neuroprotectin D1 is synthesized in the cone photoreceptor cell line 661W and elicits protection against light-induced stress. Cell Mol Neurobiol 2014; 35:197-204. [PMID: 25212825 DOI: 10.1007/s10571-014-0111-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 09/01/2014] [Indexed: 12/31/2022]
Abstract
Docosahexaenoic acid (DHA), an omega-3 fatty acid family member, is obtained by diet or synthesized from dietary essential omega-3 linolenic acid and delivered systemically to the choriocapillaris, from where it is taken up by the retinal pigment epithelium (RPE). DHA is then transported to the inner segments of photoreceptors, where it is incorporated in phospholipids during the biogenesis of outer segment disk and plasma membranes. As apical photoreceptor disks are gradually shed and phagocytized by the RPE, DHA is retrieved and recycled back to photoreceptor inner segments for reassembly into new disks. Under uncompensated oxidative stress, the docosanoid neuroprotectin D1 (NPD1), a potent mediator derived from DHA, is formed by the RPE and displays its bioactivity in an autocrine and paracrine fashion. The purpose of this study was to determine whether photoreceptors have the ability to synthesize NPD1, and whether or not this lipid mediator exerts bioactivity on these cells. For this purpose, 661W cells (mouse-derived photoreceptor cells) were used. First we asked whether these cells have the ability to form NPD1 by incubating cells with deuterium (d4)-labeled DHA exposed to dark and bright light treatments, followed by LC-MS/MS-based lipidomic analysis to identify and quantify d4-NPD1. The second question pertains to the potential bioactivity of these lipids. Therefore, cells were incubated with 9-cis-retinal in the presence of bright light that triggers cell damage and death. Following 9-cis-retinal loading, DHA, NPD1, or vehicle were added to the media and the 661W cells maintained either in darkness or under bright light. DHA and NPD1 were then quantified in cells and media. Regardless of lighting conditions, 661W cells acquired DHA from the media and synthesized 4-9 times as much d4-NPD1 under bright light treatment in the absence and presence of 9-cis-retinal compared to cells in darkness. Viability assays of 9-cis-retinal-treated cells demonstrated that 34 % of the cells survived without DHA or NPD1. However, after bright light exposure, DHA protected 23 % above control levels and NPD1 increased protection by 32 %. In conclusion, the photoreceptor cell line 661W has the capability to synthesize NPD1 from DHA when under stress, and, in turn, can be protected from stress-induced apoptosis by DHA or NPD1, indicating that photoreceptors effectively contribute to endogenous protective signaling mediated by NPD1 under stressful conditions.
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Affiliation(s)
- Y Kanan
- Department of Cell Biology, University of Oklahoma Health Sciences Center, BMSB 781, 940 Stanton L. Young Blvd., Oklahoma City, OK, 73104, USA
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194
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Mihai DM, Washington I. Vitamin A dimers trigger the protracted death of retinal pigment epithelium cells. Cell Death Dis 2014; 5:e1348. [PMID: 25058422 PMCID: PMC4123103 DOI: 10.1038/cddis.2014.314] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/24/2014] [Accepted: 05/29/2014] [Indexed: 01/05/2023]
Abstract
Cellular events responsible for the initiation of major neurodegenerative disorders of the eye leading to blindness, including age-related macular degeneration, Stargardt and Best diseases, are poorly understood. Accumulation of vitamin A dimers, such as N-retinylidene-N-retinylethanolamine (A2E) in the retinal pigment epithelium (RPE), is one of the earliest measurable events preceding retinal degeneration. However, the extent to which these dimers contribute to tissue degeneration is not clear. To determine if A2E could trigger morphological changes associated with the degenerating RPE and subsequent cell death, we evaluated its toxicity to cultured human RPE cells (ARPE-19). We show that A2E triggered the accumulation of debris followed by a protracted death. A2E was up to ≈ 14-fold more toxic than its precursor, retinaldehyde. Measurements reveal that the concentration of A2E in the aged human eye could exceed the concentration of all other retinoids, opening the possibility of A2E-triggered cell death by several reported mechanisms. Findings suggest that accumulation of vitamin A dimers such as A2E in the human eye might be responsible for the formation of ubiquitous RPE debris, an early indication of retinal degeneration, and that preventing or reducing the accumulation of vitamin A dimers is a prudent strategy to prevent blindness.
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Affiliation(s)
- D M Mihai
- Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032, USA
| | - I Washington
- Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032, USA
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195
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Malik D, Hsu T, Falatoonzadeh P, Cáceres-del-Carpio J, Tarek M, Chwa M, Atilano SR, Ramirez C, Nesburn AB, Boyer DS, Kuppermann BD, Jazwinski SM, Miceli MV, Wallace DC, Udar N, Kenney MC. Human retinal transmitochondrial cybrids with J or H mtDNA haplogroups respond differently to ultraviolet radiation: implications for retinal diseases. PLoS One 2014; 9:e99003. [PMID: 24919117 PMCID: PMC4053329 DOI: 10.1371/journal.pone.0099003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/08/2014] [Indexed: 01/04/2023] Open
Abstract
Background It has been recognized that cells do not respond equally to ultraviolet (UV) radiation but it is not clear whether this is due to genetic, biochemical or structural differences of the cells. We have a novel cybrid (cytoplasmic hybrids) model that allows us to analyze the contribution of mitochondrial DNA (mtDNA) to cellular response after exposure to sub-lethal dose of UV. mtDNA can be classified into haplogroups as defined by accumulations of specific single nucleotide polymorphisms (SNPs). Recent studies have shown that J haplogroup is high risk for age-related macular degeneration while the H haplogroup is protective. This study investigates gene expression responses in J cybrids versus H cybrids after exposure to sub-lethal doses of UV-radiation. Methodology/Principal Findings Cybrids were created by fusing platelets isolated from subjects with either H (n = 3) or J (n = 3) haplogroups with mitochondria-free (Rho0) ARPE-19 cells. The H and J cybrids were cultured for 24 hours, treated with 10 mJ of UV-radiation and cultured for an additional 120 hours. Untreated and treated cybrids were analyzed for growth rates and gene expression profiles. The UV-treated and untreated J cybrids had higher growth rates compared to H cybrids. Before treatment, J cybrids showed lower expression levels for CFH, CD55, IL-33, TGF-A, EFEMP-1, RARA, BCL2L13 and BBC3. At 120 hours after UV-treatment, the J cybrids had decreased CFH, RARA and BBC3 levels but increased CD55, IL-33 and EFEMP-1 compared to UV-treated H cybrids. Conclusion/Significance In cells with identical nuclei, the cellular response to sub-lethal UV-radiation is mediated in part by the mtDNA haplogroup. This supports the hypothesis that differences in growth rates and expression levels of complement, inflammation and apoptosis genes may result from population-specific, hereditary SNP variations in mtDNA. Therefore, when analyzing UV-induced damage in tissues, the mtDNA haplogroup background may be important to consider.
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Affiliation(s)
- Deepika Malik
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - Tiffany Hsu
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - Payam Falatoonzadeh
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - Javier Cáceres-del-Carpio
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - Mohamed Tarek
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
- Department of Ophthalmology, El-Minya University, El-Minya, Egypt
| | - Marilyn Chwa
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - Shari R. Atilano
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - Claudio Ramirez
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - Anthony B. Nesburn
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
- Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - David S. Boyer
- Retina-Vitreous Associates Medical Group; Beverly Hills, California, United States of America
| | - Baruch D. Kuppermann
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - S. Michal Jazwinski
- Tulane Center for Aging, Tulane University, New Orleans, Louisiana, United States of America
| | - Michael V. Miceli
- Tulane Center for Aging, Tulane University, New Orleans, Louisiana, United States of America
| | - Douglas C. Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Nitin Udar
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
| | - M. Cristina Kenney
- Gavin Herbert Eye Institute, University California Irvine, Irvine, California, United States of America
- Department of Pathology and Laboratory Medicine, University California Irvine, Irvine, California, United States of America
- * E-mail:
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196
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Aging leads to elevation of O-GlcNAcylation and disruption of mitochondrial homeostasis in retina. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:425705. [PMID: 24987494 PMCID: PMC4060167 DOI: 10.1155/2014/425705] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/09/2014] [Indexed: 12/21/2022]
Abstract
Retina is particularly susceptible to aging as oxidative damage accumulates within retina, leading to age-related retinal dysfunction or even visual loss. However, the underlying mechanisms still remain obscure and effective therapeutic strategy is urgently in need. Here, we quested for the answer particularly focusing on mitochondrial homeostasis and O-GlcNAcylation in rat retina. By comparing expression of electron transfer chain complexes and key factors in mitochondrial biogenesis and dynamics in retinas of aged and young Sprague-Dawley rats, we found that mitochondrial Complex I, II, IV and V were increased in aged retina with decreased mtTFA and Mfn2. Also, we noticed that p38 and JNK of MAPK signaling were substantially more activated in aged retina, suggesting stress induction. In addition, we found that pan-O-GlcNAcylation was remarkably stronger with lower OGA expression in aged retina. To further elucidate the roles of Mfn2 and O-GlcNAcylation, we employed ARPE-19 cells and found that ATP production, oxygen consumption, and mitochondrial membrane potential were reduced and ROS level was increased by Mfn2 knockdown, while treating with PUGNAc or UDP-GlcNAc heightened oxygen consumption and reduced ROS. Our results suggest disrupted mitochondrial homeostasis may increase oxidative stress; yet enhanced O-GlcNAcylation might defend against oxidative stress and promote mitochondrial respiration in aged retina.
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197
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Cano M, Wang L, Wan J, Barnett BP, Ebrahimi K, Qian J, Handa JT. Oxidative stress induces mitochondrial dysfunction and a protective unfolded protein response in RPE cells. Free Radic Biol Med 2014; 69:1-14. [PMID: 24434119 PMCID: PMC3960355 DOI: 10.1016/j.freeradbiomed.2014.01.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/06/2013] [Accepted: 01/03/2014] [Indexed: 01/18/2023]
Abstract
How cells degenerate from oxidative stress in aging-related disease is incompletely understood. This study's intent was to identify key cytoprotective pathways activated by oxidative stress and determine the extent of their protection. Using an unbiased strategy with microarray analysis, we found that retinal pigmented epithelial (RPE) cells treated with cigarette smoke extract (CSE) had overrepresented genes involved in the antioxidant and unfolded protein response (UPR). Differentially expressed antioxidant genes were predominantly located in the cytoplasm, with no induction of genes that neutralize superoxide and H2O2 in the mitochondria, resulting in accumulation of superoxide and decreased ATP production. Simultaneously, CSE induced the UPR sensors IRE1α, p-PERK, and ATP6, including CHOP, which was cytoprotective because CHOP knockdown decreased cell viability. In mice given intravitreal CSE, the RPE had increased IRE1α and decreased ATP and developed epithelial-mesenchymal transition, as suggested by decreased LRAT abundance, altered ZO-1 immunolabeling, and dysmorphic cell shape. Mildly degenerated RPE from early age-related macular degeneration (AMD) samples had prominent IRE1α, but minimal mitochondrial TOM20 immunolabeling. Although oxidative stress is thought to induce an antioxidant response with cooperation between the mitochondria and the ER, herein we show that mitochondria become impaired sufficiently to induce epithelial-mesenchymal transition despite a protective UPR. With similar responses in early AMD samples, these results suggest that mitochondria are vulnerable to oxidative stress despite a protective UPR during the early phases of aging-related disease.
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Affiliation(s)
- Marisol Cano
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Lei Wang
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Jun Wan
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Bradley P Barnett
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Katayoon Ebrahimi
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Jiang Qian
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - James T Handa
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
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Bakeeva LE, Vays VB, Vangely IM. Age-related alterations of mitochondria from muscle tissue. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2014. [DOI: 10.1134/s1990747813050024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gene therapy for mitochondrial diseases: Leber Hereditary Optic Neuropathy as the first candidate for a clinical trial. C R Biol 2014; 337:193-206. [PMID: 24702846 DOI: 10.1016/j.crvi.2013.11.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 12/30/2022]
Abstract
Mitochondrial disorders cannot be ignored anymore in most medical disciplines; indeed their minimum estimated prevalence is superior to 1 in 5000 births. Despite the progress made in the last 25 years on the identification of gene mutations causing mitochondrial pathologies, only slow progress was made towards their effective treatments. Ocular involvement is a frequent feature in mitochondrial diseases and corresponds to severe and irreversible visual handicap due to retinal neuron loss and optic atrophy. Interestingly, three clinical trials for Leber Congenital Amaurosis due to RPE65 mutations are ongoing since 2007. Overall, the feasibility and safety of ocular Adeno-Associated Virus delivery in adult and younger patients and consistent visual function improvements have been demonstrated. The success of gene-replacement therapy for RPE65 opens the way for the development of similar approaches for a broad range of eye disorders, including those with mitochondrial etiology such as Leber Hereditary Optic Neuropathy (LHON).
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200
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Adijanto J, Philp NJ. Cultured primary human fetal retinal pigment epithelium (hfRPE) as a model for evaluating RPE metabolism. Exp Eye Res 2014; 126:77-84. [PMID: 24485945 DOI: 10.1016/j.exer.2014.01.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/15/2014] [Accepted: 01/19/2014] [Indexed: 12/20/2022]
Abstract
Mitochondrial dysfunction has been shown to contribute to age-related and proliferative retinal diseases. Over the past decade, the primary human fetal RPE (hfRPE) culture model has emerged as an effective tool for studying RPE function and mechanisms of retinal diseases. This model system has been rigorously characterized and shown to closely resemble native RPE cells at the genomic and protein level, and that they are capable of accomplishing the characteristic functions of a healthy native RPE (e.g., rod phagocytosis, ion and fluid transport, and retinoid cycle). In this review, we demonstrated that the metabolic activity of the RPE is an indicator of its health and state of differentiation, and present the hfRPE culture model as a valuable in vitro system for evaluating RPE metabolism in the context of RPE differentiation and retinal disease.
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Affiliation(s)
- Jeffrey Adijanto
- Thomas Jefferson University, Dept. of Pathology, Anatomy, & Cell Biology, 1020 Locust Street, Rm315, Philadelphia, PA 19107, USA.
| | - Nancy J Philp
- Thomas Jefferson University, Dept. of Pathology, Anatomy, & Cell Biology, 1020 Locust Street, Rm315, Philadelphia, PA 19107, USA.
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