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Farnoodian M, Bose D, Barone F, Nelson LM, Boyle M, Jun B, Do K, Gordon W, Guerin MAK, Perera R, Ji JX, Cogliati T, Sharma R, Brooks BP, Bazan NG, Bharti K. Retina and RPE lipid profile changes linked with ABCA4 associated Stargardt's maculopathy. Pharmacol Ther 2023; 249:108482. [PMID: 37385300 PMCID: PMC10530239 DOI: 10.1016/j.pharmthera.2023.108482] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/20/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Stargardt maculopathy, caused predominantly by mutations in the ABCA4 gene, is characterized by an accumulation of non-degradable visual pigment derivative, lipofuscin, in the retinal pigment epithelium (RPE) - resulting in RPE atrophy. RPE is a monolayer tissue located adjacent to retinal photoreceptors and regulates their health and functioning; RPE atrophy triggers photoreceptor cell death and vision loss in Stargardt patients. Previously, ABCA4 mutations in photoreceptors were thought to be the major contributor to lipid homeostasis defects in the eye. Recently, we demonstrated that ABCA4 loss of function in the RPE leads to cell-autonomous lipid homeostasis defects. Our work underscores that an incomplete understanding of lipid metabolism and lipid-mediated signaling in the retina and RPE are potential causes for lacking treatments for this disease. Here we report altered lipidomic in mouse and human Stargardt models. This work provides the basis for therapeutics that aim to restore lipid homeostasis in the retina and the RPE.
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Affiliation(s)
- Mitra Farnoodian
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Devika Bose
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Francesca Barone
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Luke Mathew Nelson
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Marisa Boyle
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Bokkyoo Jun
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Khanh Do
- Faculty of Medicine, Phenikaa University, Hanoi, Viet Nam
| | - William Gordon
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Marie-Audrey Kautzmann Guerin
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Rasangi Perera
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Jeff X Ji
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Tiziana Cogliati
- Division of Aging Biology, National Institute on Aging, National Institute of Health, Bethesda, MD, USA
| | - Ruchi Sharma
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Nicolas G Bazan
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Kapil Bharti
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA.
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2
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Chen L, Liu Y, Mu H, Li H, Liu S, Zhu M, Bu Y, Wu B. Effects of perfluorobutane sulfonate and perfluorooctane sulfonate on lipid homeostasis in mouse liver. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 315:120403. [PMID: 36228861 DOI: 10.1016/j.envpol.2022.120403] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/20/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Perfluorobutane sulfonate (PFBS), an alternative to perfluorooctane sulfonate (PFOS), has been increasingly used in recent years. However, emerging evidence has raised concerns about the potential health risks of PFBS. Here, the toxicityof low-dose PFBS on livers was explored and compared with that of PFOS. Adult C57BL/6 mice were exposed to 10 μg/L, 500 μg/L PFBS, or 500 μg/L PFOS for 28 days through drinking water. At the phenotypic level, no liver damage was observed in the 10 μg/L PFBS group. The cell apoptosis and decrease of CAT activities were observed in the 500 μg/L PFBS group, while accumulation of lipid droplets, increase of CAT activities and TAG levels were found in the 500 μg/L PFOS group. Lipidomics analysis revealed that 138, 238, and 310 lipids were significantly changed in the 10 μg/L, 500 μg/L PFBS and 500 μg/L PFOS groups, respectively. The two PFBS-treated groups induced similar global lipid changes in a dose-dependent manner, which were distinct from PFOS. Overall, PFBS exposure induced an increase in phosphatidylcholines and sphingomyelins, but a decrease in phosphatidylinositol. PFOS exposure caused an increase in triacylglycerols. This study provides more evidence on the health hazards caused by exposure to low-dose PFBS.
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Affiliation(s)
- Ling Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, 210023, PR China
| | - Yafeng Liu
- Department of Environmental Science, School of Engineering, China Pharmaceutical University, Nanjing, 211198, PR China
| | - Hongxin Mu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, 210023, PR China
| | - Huan Li
- Department of Environmental Science, School of Engineering, China Pharmaceutical University, Nanjing, 211198, PR China
| | - Su Liu
- Department of Environmental Science, School of Engineering, China Pharmaceutical University, Nanjing, 211198, PR China; School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, 210023, China
| | - Mengyuan Zhu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, 210023, PR China
| | - Yuanqing Bu
- Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Nanjing Institute of Environmental Science, Ministry of Ecology and Environment, Nanjing, 210042, China
| | - Bing Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, 210023, PR China.
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3
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Characterization and Roles of Membrane Lipids in Fatty Liver Disease. MEMBRANES 2022; 12:membranes12040410. [PMID: 35448380 PMCID: PMC9025760 DOI: 10.3390/membranes12040410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 12/12/2022]
Abstract
Obesity has reached global epidemic proportions and it affects the development of insulin resistance, type 2 diabetes, fatty liver disease and other metabolic diseases. Membrane lipids are important structural and signaling components of the cell membrane. Recent studies highlight their importance in lipid homeostasis and are implicated in the pathogenesis of fatty liver disease. Here, we discuss the numerous membrane lipid species and their metabolites including, phospholipids, sphingolipids and cholesterol, and how dysregulation of their composition and physiology contribute to the development of fatty liver disease. The development of new genetic and pharmacological mouse models has shed light on the role of lipid species on various mechanisms/pathways; these lipids impact many aspects of the pathophysiology of fatty liver disease and could potentially be targeted for the treatment of fatty liver disease.
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4
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Tran PM, Tang SS, Salgado-Pabón W. Staphylococcus aureus β-Toxin Exerts Anti-angiogenic Effects by Inhibiting Re-endothelialization and Neovessel Formation. Front Microbiol 2022; 13:840236. [PMID: 35185854 PMCID: PMC8851161 DOI: 10.3389/fmicb.2022.840236] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/11/2022] [Indexed: 12/25/2022] Open
Abstract
Staphylococcus aureus causes severe, life-threatening infections that often are complicated by severe local and systemic pathologies with non-healing lesions. A classic example is S. aureus infective endocarditis (IE), where the secreted hemolysin β-toxin potentiates the disease via its sphingomyelinase and biofilm ligase activities. Although these activities dysregulate human aortic endothelial cell activation, β-toxin effect on endothelial cell function in wound healing has not been addressed. With the use of the ex vivo rabbit aortic ring model, we provide evidence that β-toxin prevents branching microvessel formation, highlighting its ability to interfere with tissue re-vascularization and vascular repair. We show that β-toxin specifically targets both human aortic endothelial cell proliferation and cell migration and inhibits human umbilical vein endothelial cell rearrangement into capillary-like networks in vitro. Proteome arrays specific for angiogenesis-related molecules provided evidence that β-toxin promotes an inhibitory profile in endothelial cell monolayers, specifically targeting production of TIMP-1, TIMP-4, and IGFBP-3 to counter the effect of a pro-angiogenic environment. Dysregulation in the production of these molecules is known to result in sprouting defects (including deficient cell proliferation, migration, and survival), vessel instability and/or vascular regression. When endothelial cells are grown under re-endothelialization/wound healing conditions, β-toxin decreases the pro-angiogenic molecule MMP-8 and increases the anti-angiogenic molecule endostatin. Altogether, the data indicate that β-toxin is an anti-angiogenic virulence factor and highlight a mechanism where β-toxin exacerbates S. aureus invasive infections by interfering with tissue re-vascularization and vascular repair.
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Affiliation(s)
- Phuong M Tran
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States.,Department of Microbiology and Immunology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Sharon S Tang
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - Wilmara Salgado-Pabón
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States
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5
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Lewandowski D, Sander CL, Tworak A, Gao F, Xu Q, Skowronska-Krawczyk D. Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life. Prog Retin Eye Res 2021; 89:101037. [PMID: 34971765 PMCID: PMC10361839 DOI: 10.1016/j.preteyeres.2021.101037] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022]
Abstract
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
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Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Christopher L Sander
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Qianlan Xu
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA.
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6
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Shiwani HA, Elfaki MY, Memon D, Ali S, Aziz A, Egom EE. Updates on sphingolipids: Spotlight on retinopathy. Biomed Pharmacother 2021; 143:112197. [PMID: 34560541 DOI: 10.1016/j.biopha.2021.112197] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 02/05/2023] Open
Abstract
The sphingolipids ceramide (Cer), ceramide-1-phosphate (C1P), sphingosine (Sph), and sphingosine-1-phosphate (S1P)) are key signaling molecules that regulate many patho-biological processes. During the last decade, they have gained increasing attention since they may participate in important and numerous retinal processes, such as neuronal survival and death, proliferation and migration of neuronal and vascular cells, inflammation, and neovascularization. Cer for instance has emerged as a key mediator of inflammation and death of neuronal and retinal pigment epithelium cells in experimental models of retinopathies such as glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa. S1P may have opposite biological actions, preventing photoreceptor and ganglion cell degeneration but also promoting inflammation, fibrosis, and neovascularization in AMD, glaucoma, and pro-fibrotic disorders. Alterations in Cer, S1P, and ceramide 1- phosphate may also contribute to uveitis. Furthermore, use of inhibitors that either prevent Cer increase or modulate S1P signaling, such as Myriocin, desipramine, and Fingolimod (FTY720), have been shown to preserve neuronal viability and retinal function. Collectively, the expanding role for these sphingolipids in the modulation of vital processes in retina cell types and in their dysregulation in retinal degenerations makes them attractive therapeutic targets.
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Affiliation(s)
- Haaris A Shiwani
- Department of Ophthalmology, Royal Preston Hospital, United Kingdom.
| | | | - Danyal Memon
- Department of Cardiology, Children's Health Ireland at Crumlin, Dublin, Ireland
| | - Suhayb Ali
- Department of Acute Medicine, Ulster Hospital, Belfast, United Kingdom
| | - Abdul Aziz
- Department of Respiratory Medicine, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Emmanuel E Egom
- Institut du Savoir Montfort (ISM), Hôpital Montfort, University of Ottawa, Ottawa, ON, Canada; Laboratory of Endocrinology and Radioisotopes, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaoundé, Cameroon.
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7
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Simon MV, Basu SK, Qaladize B, Grambergs R, Rotstein NP, Mandal N. Sphingolipids as critical players in retinal physiology and pathology. J Lipid Res 2021; 62:100037. [PMID: 32948663 PMCID: PMC7933806 DOI: 10.1194/jlr.tr120000972] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/04/2020] [Indexed: 12/24/2022] Open
Abstract
Sphingolipids have emerged as bioactive lipids involved in the regulation of many physiological and pathological processes. In the retina, they have been established to participate in numerous processes, such as neuronal survival and death, proliferation and migration of neuronal and vascular cells, inflammation, and neovascularization. Dysregulation of sphingolipids is therefore crucial in the onset and progression of retinal diseases. This review examines the involvement of sphingolipids in retinal physiology and diseases. Ceramide (Cer) has emerged as a common mediator of inflammation and death of neuronal and retinal pigment epithelium cells in animal models of retinopathies such as glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa. Sphingosine-1-phosphate (S1P) has opposite roles, preventing photoreceptor and ganglion cell degeneration but also promoting inflammation, fibrosis, and neovascularization in AMD, glaucoma, and pro-fibrotic disorders. Alterations in Cer, S1P, and ceramide 1-phosphate may also contribute to uveitis. Notably, use of inhibitors that either prevent Cer increase or modulate S1P signaling, such as Myriocin, desipramine, and Fingolimod (FTY720), preserves neuronal viability and retinal function. These findings underscore the relevance of alterations in the sphingolipid metabolic network in the etiology of multiple retinopathies and highlight the potential of modulating their metabolism for the design of novel therapeutic approaches.
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Affiliation(s)
- M Victoria Simon
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Sandip K Basu
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Bano Qaladize
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Richard Grambergs
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina.
| | - Nawajes Mandal
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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8
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Functional imaging of mitochondria in retinal diseases using flavoprotein fluorescence. Eye (Lond) 2020; 35:74-92. [PMID: 32709959 DOI: 10.1038/s41433-020-1110-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/01/2020] [Accepted: 07/16/2020] [Indexed: 12/27/2022] Open
Abstract
Mitochondria are critical for cellular energy production and homeostasis. Oxidative stress and associated mitochondrial dysfunction are integral components of the pathophysiology of retinal diseases, including diabetic retinopathy (DR), age-related macular degeneration, and glaucoma. Within mitochondria, flavoproteins are oxidized and reduced and emit a green autofluorescence when oxidized following blue light excitation. Recently, a noninvasive imaging device was developed to measure retinal flavoprotein fluorescence (FPF). Thus, oxidized FPF can act as a biomarker of mitochondrial dysfunction. This review article describes the literature surrounding mitochondrial FPF imaging in retinal disease. The authors describe the role of mitochondrial dysfunction in retinal diseases, experiments using FPF as a marker of mitochondrial dysfunction in vitro, the three generations of retinal FPF imaging devices, and the peer-reviewed publications that have examined FPF imaging in patients. Finally, the authors report their own study findings. Goals were to establish normative reference levels for FPF intensity and heterogeneity in healthy eyes, to compare between healthy eyes and eyes with diabetes and DR, and to compare across stages of DR. The authors present methods to calculate a patient's expected FPF values using baseline characteristics. FPF intensity and heterogeneity were elevated in diabetic eyes compared to age-matched control eyes, and in proliferative DR compared to diabetic eyes without retinopathy. In diabetic eyes, higher FPF heterogeneity was associated with poorer visual acuity. In conclusion, while current retinal imaging modalities frequently focus on structural features, functional mitochondrial imaging shows promise as a metabolically targeted tool to evaluate retinal disease.
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9
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Markitantova Y, Simirskii V. Inherited Eye Diseases with Retinal Manifestations through the Eyes of Homeobox Genes. Int J Mol Sci 2020; 21:E1602. [PMID: 32111086 PMCID: PMC7084737 DOI: 10.3390/ijms21051602] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
Retinal development is under the coordinated control of overlapping networks of signaling pathways and transcription factors. The paper was conceived as a review of the data and ideas that have been formed to date on homeobox genes mutations that lead to the disruption of eye organogenesis and result in inherited eye/retinal diseases. Many of these diseases are part of the same clinical spectrum and have high genetic heterogeneity with already identified associated genes. We summarize the known key regulators of eye development, with a focus on the homeobox genes associated with monogenic eye diseases showing retinal manifestations. Recent advances in the field of genetics and high-throughput next-generation sequencing technologies, including single-cell transcriptome analysis have allowed for deepening of knowledge of the genetic basis of inherited retinal diseases (IRDs), as well as improve their diagnostics. We highlight some promising avenues of research involving molecular-genetic and cell-technology approaches that can be effective for IRDs therapy. The most promising neuroprotective strategies are aimed at mobilizing the endogenous cellular reserve of the retina.
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10
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Update on Myopia Risk Factors and Microenvironmental Changes. J Ophthalmol 2019; 2019:4960852. [PMID: 31781378 PMCID: PMC6875023 DOI: 10.1155/2019/4960852] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 08/06/2019] [Accepted: 09/05/2019] [Indexed: 12/13/2022] Open
Abstract
The focus of this update is to emphasize the recent advances in the pathogenesis and various molecular key approaches associated with myopia in order to reveal new potential therapeutic targets. We review the current evidence for its complex genetics and evaluate the known or candidate genes and loci. In addition, we discuss recent investigations regarding the role of environmental factors. This paper also covers current research aimed at elucidating the signaling pathways involved in the pathogenesis of myopia.
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11
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Alrbyawi H, Poudel I, Dash RP, Srinivas NR, Tiwari AK, Arnold RD, Babu RJ. Role of Ceramides in Drug Delivery. AAPS PharmSciTech 2019; 20:287. [PMID: 31410612 DOI: 10.1208/s12249-019-1497-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/31/2019] [Indexed: 12/20/2022] Open
Abstract
Ceramides belong to the sphingolipid group of lipids, which serve as both intracellular and intercellular messengers and as regulatory molecules that play essential roles in signal transduction, inflammation, angiogenesis, and metabolic disorders such as diabetes, neurodegenerative diseases, and cancer cell degeneration. Ceramides also play an important structural role in cell membranes by increasing their rigidity, creating micro-domains (rafts and caveolae), and altering membrane permeability; all these events are involved in the cell signaling. Ceramides constitute approximately half of the lipid composition in the human skin contributing to barrier function as well as epidermal signaling as they affect both proliferation and apoptosis of keratinocytes. Incorporation of ceramides in topical preparations as functional lipids appears to alter skin barrier functions. Ceramides also appear to enhance the bioavailability of drugs by acting as lipid delivery systems. They appear to regulate the ocular inflammation signaling, and external ceramides have shown relief in the anterior and posterior eye disorders. Ceramides play a structural role in liposome formulations and enhance the cellular uptake of amphiphilic drugs, such as chemotherapies. This review presents an overview of the various biological functions of ceramides, and their utility in topical, oral, ocular, and chemotherapeutic drug delivery.
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12
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Simón MV, Prado Spalm FH, Vera MS, Rotstein NP. Sphingolipids as Emerging Mediators in Retina Degeneration. Front Cell Neurosci 2019; 13:246. [PMID: 31244608 PMCID: PMC6581011 DOI: 10.3389/fncel.2019.00246] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/17/2019] [Indexed: 12/12/2022] Open
Abstract
The sphingolipids ceramide (Cer), sphingosine-1-phosphate (S1P), sphingosine (Sph), and ceramide-1-phosphate (C1P) are key signaling molecules that regulate major cellular functions. Their roles in the retina have gained increasing attention during the last decade since they emerge as mediators of proliferation, survival, migration, neovascularization, inflammation and death in retina cells. As exacerbation of these processes is central to retina degenerative diseases, they appear as crucial players in their progression. This review analyzes the functions of these sphingolipids in retina cell types and their possible pathological roles. Cer appears as a key arbitrator in diverse retinal pathologies; it promotes inflammation in endothelial and retina pigment epithelium (RPE) cells and its increase is a common feature in photoreceptor death in vitro and in animal models of retina degeneration; noteworthy, inhibiting Cer synthesis preserves photoreceptor viability and functionality. In turn, S1P acts as a double edge sword in the retina. It is essential for retina development, promoting the survival of photoreceptors and ganglion cells and regulating proliferation and differentiation of photoreceptor progenitors. However, S1P has also deleterious effects, stimulating migration of Müller glial cells, angiogenesis and fibrosis, contributing to the inflammatory scenario of proliferative retinopathies and age related macular degeneration (AMD). C1P, as S1P, promotes photoreceptor survival and differentiation. Collectively, the expanding role for these sphingolipids in the regulation of critical processes in retina cell types and in their dysregulation in retina degenerations makes them attractive targets for treating these diseases.
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Affiliation(s)
- M Victoria Simón
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Facundo H Prado Spalm
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Marcela S Vera
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
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13
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Role of Bioactive Sphingolipids in Inflammation and Eye Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1161:149-167. [PMID: 31562629 DOI: 10.1007/978-3-030-21735-8_14] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inflammation is a common underlying factor in a diversity of ocular diseases, ranging from macular degeneration, autoimmune uveitis, glaucoma, diabetic retinopathy and microbial infection. In addition to the variety of known cellular mediators of inflammation, such as cytokines, chemokines and lipid mediators, there is now considerable evidence that sphingolipid metabolites also play a central role in the regulation of inflammatory pathways. Various sphingolipid metabolites, such as ceramide (Cer), ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P), and lactosylceramide (LacCer) can contribute to ocular inflammatory diseases through multiple pathways. For example, inflammation generates Cer from sphingomyelins (SM) in the plasma membrane, which induces death receptor ligand formation and leads to apoptosis of retinal pigment epithelial (RPE) and photoreceptor cells. Inflammatory stress by reactive oxygen species leads to LacCer accumulation and S1P secretion and induces proliferation of retinal endothelial cells and eventual formation of new vessels. In sphingolipid/lysosomal storage disorders, sphingolipid metabolites accumulate in lysosomes and can cause ocular disorders that have an inflammatory etiology. Sphingolipid metabolites activate complement factors in the immune-response mediated pathogenesis of macular degeneration. These examples highlight the integral association between sphingolipids and inflammation in ocular diseases.
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14
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Inflammatory Ocular Diseases and Sphingolipid Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1159:139-152. [DOI: 10.1007/978-3-030-21162-2_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Adipose-Derived Mesenchymal Stem Cells Migrate and Rescue RPE in the Setting of Oxidative Stress. Stem Cells Int 2018; 2018:9682856. [PMID: 30651740 PMCID: PMC6311721 DOI: 10.1155/2018/9682856] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/27/2018] [Accepted: 10/08/2018] [Indexed: 02/07/2023] Open
Abstract
Oxidative stress leads to the degeneration of retinal pigment epithelial (RPE) and photoreceptor cells. We evaluated the potential of adipose-derived mesenchymal stem cells (ASCs) as a therapeutic tool by studying the migration capacity of ASCs in vitro and their protective effect against RPE cell death under oxidative stress in vitro and in vivo. ASCs exhibited enhanced migration when exposed to conditioned medium of oxidative stressed RPE cells obtained by hydrogen peroxide. Migration-related axis SDF-1/CXCR4 was studied, and upregulation of SDF-1 in stressed RPE and of CXCR4 in ASCs was detected. Moreover, ASCs' conditioned medium prevented H2O2-induced cell death of RPE cells. Early passage ASCs had high expression level of HGF, low VEGF levels, and unmodulated IL-1β levels, compared to late passage ASCs. Thus, early passage ASCs show the potential to migrate towards damaged RPE cells and protect them in a paracrine manner from cell death induced by oxidative stress. In vivo, mice received systemic injection of NaIO3, and 72 h later, ASCs were transplanted in the subretinal space. Seven days after ASC transplantation, the eyes were enucleated fixed and frozen for immunohistochemical analysis. Under such conditions, ASC-treated mice showed preservation of nuclear layers in the outer nuclear layer and stronger staining of RPE and photoreceptor layer, compared to PBS-treated mice. Taken together, our results indicate that ASCs are able to home in on damaged RPE cells and protect against damage to the RPE and PR layers caused by oxidative stress. These data imply the potential that ASCs have in regenerating RPE under oxidative stress, providing the basis for a therapeutic approach to retinal degeneration diseases related to oxidative stress that could help save the eyesight of millions of people worldwide.
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Sugano E, Edwards G, Saha S, Wilmott LA, Grambergs RC, Mondal K, Qi H, Stiles M, Tomita H, Mandal N. Overexpression of acid ceramidase (ASAH1) protects retinal cells (ARPE19) from oxidative stress. J Lipid Res 2018; 60:30-43. [PMID: 30413652 DOI: 10.1194/jlr.m082198] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 10/26/2018] [Indexed: 01/08/2023] Open
Abstract
Over 11 million people in the United States alone have some form of age-related macular degeneration (AMD). Oxidative stress, cell death, and the degeneration of retinal pigment epithelial (RPE) cells contribute to AMD pathology. Recent evidence suggests that ceramide (Cer), a cellular sphingolipid mediator that acts as a second messenger to induce apoptosis, might play a role in RPE cell death. The lysosomal breakdown of Cer by acid ceramidase [N-acylsphingosine amidohydrolase (ASAH)1] into sphingosine (Sph) is the major source for Sph 1-phosphate production, which has an opposing role to Cer and provides cytoprotection. Here, we investigated the role of Cer in human RPE-derived ARPE19 cells under hydrogen peroxide-induced oxidative stress, and show that Cer and hexosyl-Cer levels increase in the oxidatively stressed ARPE19 cells, which can be prevented by overexpression of lysosomal ASAH1. This study demonstrates that oxidative stress generates sphingolipid death mediators in retinal cells and that induction of ASAH1 could rescue retinal cells from oxidative stress by hydrolyzing excess Cers.
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Affiliation(s)
- Eriko Sugano
- Division of Science and Engineering, Iwate University, Morioka 020-8551, Japan
| | - Genea Edwards
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Saikat Saha
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Lynda A Wilmott
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Richard C Grambergs
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Koushik Mondal
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Hui Qi
- Department of Ophthalmology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104
| | - Megan Stiles
- Department of Ophthalmology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104
| | - Hiroshi Tomita
- Division of Science and Engineering, Iwate University, Morioka 020-8551, Japan
| | - Nawajes Mandal
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163 .,Department of Ophthalmology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104.,Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163
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Evaluation of serum sphingolipids and the influence of genetic risk factors in age-related macular degeneration. PLoS One 2018; 13:e0200739. [PMID: 30071029 PMCID: PMC6071970 DOI: 10.1371/journal.pone.0200739] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 07/02/2018] [Indexed: 12/22/2022] Open
Abstract
Sphingolipids are bioactive molecules associated with oxidative stress, inflammation, and neurodegenerative diseases, but poorly studied in the context of age-related macular degeneration (AMD), a prevalent sight-threatening disease of the ageing retina. Here, we found higher serum levels of hexosylceramide (HexCer) d18:1/16:0 in patients with choroidal neovascularization (CNV) and geographic atrophy (GA), two manifestations of late stage AMD, and higher ceramide (Cer) d18:1/16:0 levels in GA patients. A sensitivity analysis of genetic variants known to be associated with late stage AMD showed that rs1061170 (p.Y402H) in the complement factor H (CFH) gene influences the association of Cer d18:1/16:0 with GA. To understand the possible influence of this genetic variant on ceramide levels, we established a cell-based assay to test the modulation of genes in the ceramide metabolism by factor H-like protein 1 (FHL-1), an alternative splicing variant of CFH that also harbors the 402 residue. We first showed that malondialdehyde-acetaldehyde adducts, an oxidation product commonly found in AMD retinas, induces an increase in ceramide levels in WERI-Rb1 cells in accordance with an increased expression of ceramide synthesis genes. Then, we observed that cells exposed to the non-risk FHL-1:Y402, but not the risk associated variant FHL-1:H402 or full-length CFH, downregulated ceramide synthase 2 and ceramide glucosyltransferase gene expression. Together, our findings show that serum ceramide and hexosylceramide species are altered in AMD patients and that ceramide levels may be influenced by AMD associated risk variants.
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Oxidative stress in myopia. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:750637. [PMID: 25922643 PMCID: PMC4397465 DOI: 10.1155/2015/750637] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 03/10/2015] [Accepted: 03/17/2015] [Indexed: 12/25/2022]
Abstract
Myopia affected approximately 1.6 billion people worldwide in 2000, and it is expected to increase to 2.5 billion by 2020. Although optical problems can be corrected by optics or surgical procedures, normal myopia and high myopia are still an unsolved medical problem. They frequently predispose people who have them to suffer from other eye pathologies: retinal detachment, glaucoma, macular hemorrhage, cataracts, and so on being one of the main causes of visual deterioration and blindness. Genetic and environmental factors have been associated with myopia. Nevertheless, lack of knowledge in the underlying physiopathological molecular mechanisms has not permitted an adequate diagnosis, prevention, or treatment to be found. Nowadays several pieces of evidence indicate that oxidative stress may help explain the altered regulatory pathways in myopia and the appearance of associated eye diseases. On the one hand, oxidative damage associated with hypoxia myopic can alter the neuromodulation that nitric oxide and dopamine have in eye growth. On the other hand, radical superoxide or peroxynitrite production damage retina, vitreous, lens, and so on contributing to the appearance of retinopathies, retinal detachment, cataracts and so on. The objective of this review is to suggest that oxidative stress is one of the key pieces that can help solve this complex eye problem.
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Ceramide inhibits connective tissue growth factor expression by human retinal pigment epithelial cells. Cytokine 2014; 68:137-40. [PMID: 24758915 DOI: 10.1016/j.cyto.2014.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 02/14/2014] [Accepted: 03/27/2014] [Indexed: 11/20/2022]
Abstract
Connective tissue growth factor (CTGF) is known to be involved in retinal fibrotic disorders. We used human retinal pigment epithelial cells (HRPE), which play critical roles in retinal fibrosis, to examine the expression of CTGF and its regulation by ceramide and TGF-β. Real-time PCR analysis showed downregulation of CTGF mRNA by C2 ceramide and upregulation by TGF-β. C2 ceramide also inhibited constitutive and TGF-β-enhanced CTGF secretion by HRPE cells. Predominant secretion (>80% of total) of CTGF from the apical side was observed in highly polarized HRPE cells. Fumonosin, an inhibitor of ceramide synthesis, stimulated CTGF secretion while 4HPR, an activator of ceramide synthesis, downregulated CTGF secretion. Based on these results demonstrating ceramide regulation of CTGF secretion by HRPE, we suggest that ceramide may have therapeutic potential for the treatment of retinal fibrotic diseases by inhibiting CTGF production.
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Cai L, Liao HF, Zhang XJ, Shao Y, Xu M, Yi JL. Acetylcholinesterase function in apoptotic retina pigment epithelial cells induced by H2O2. Int J Ophthalmol 2013; 6:772-7. [PMID: 24392323 DOI: 10.3980/j.issn.2222-3959.2013.06.06] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 09/05/2013] [Indexed: 11/02/2022] Open
Abstract
AIM To investigate the acetylcholinesterase (AChE) expression involved in retina pigment epithelial (RPE) apoptosis induced by higher concentrations H2O2. METHODS The human retinal pigment epithelium cell line ARPE-19 was from ATCC (Rockville, MD). Cultured ARPE-19 cells were treated with H2O2 at 0, 250, 500, 1 000, 2 000µmol/L and cell viability was measured with MTT assay. AChE expression and DNA fragments were analyzed by immunocytochemistry, TUNEL and PARP-1 Western blotting. RESULTS Immunofluorescence detected AChE exist in the normal human retinal tissue. When H2O2 >500µmol/L, AChE expression showed an increase after 2h, and this concentration was selected for the present study. RPE cell was induced with 1 000µmol/L H2O2 for 2h, compared to the control group, cell activity decline detected by MTT, AChE and PARP-1 protein expression was significantly increased detected by Western blotting. AChE immunofluorescence staining was positive in RPE cell after H2O2 incubate 2h. In addition, pretreatment with 100µmol/L epigallocatechin gallate (EGCG), cell viability increased from 31.20%±3.90% to 70.23%±12.96%. CONCLUSION AChE is weakly expressed in normal human RPE cells. Stimulation with H2O2 caused the stable increase of AChE expression in RPE cells, which may indicate that AChE may be an important role in AMD.
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Affiliation(s)
- Li Cai
- Jiangxi Research Institute of Ophthalmology and Visual Sciences, Nanchang 330006, Jiangxi Province, China
| | - Hong-Fei Liao
- Jiangxi Research Institute of Ophthalmology and Visual Sciences, Nanchang 330006, Jiangxi Province, China
| | - Xue-Jun Zhang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Shanghai 200000, China
| | - Yi Shao
- Department of Ophthalmology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Man Xu
- Jiangxi Research Institute of Ophthalmology and Visual Sciences, Nanchang 330006, Jiangxi Province, China
| | - Jing-Lin Yi
- Jiangxi Research Institute of Ophthalmology and Visual Sciences, Nanchang 330006, Jiangxi Province, China
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Chen H, Chan AY, Stone DU, Mandal NA. Beyond the cherry-red spot: Ocular manifestations of sphingolipid-mediated neurodegenerative and inflammatory disorders. Surv Ophthalmol 2013; 59:64-76. [PMID: 24011710 DOI: 10.1016/j.survophthal.2013.02.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 02/06/2013] [Accepted: 02/12/2013] [Indexed: 01/05/2023]
Abstract
Sphingolipids are a ubiquitous membrane lipid present in every cell and found most abundantly in neural tissues. Disorders such as Tay-Sachs or Niemann-Pick disease are the most familiar examples of dysfunction in sphingolipid metabolism and are typically associated with neurodegeneration and ocular findings such as blindness. More recently, the role of bioactive sphingolipids has been established in a multitude of cellular events, including cell survival, growth, senescence and apoptosis, inflammation, and neovascularization. We discuss our current knowledge and understanding of sphingolipid metabolism and signaling in the pathogenesis of ocular diseases.
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Affiliation(s)
- Hui Chen
- Department of Ophthalmology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma, USA.,Dean A. McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Annie Y Chan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma, USA.,Dean A. McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Donald U Stone
- Department of Ophthalmology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma, USA.,Dean A. McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Nawajes A Mandal
- Department of Ophthalmology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma, USA.,Dean A. McGee Eye Institute, Oklahoma City, Oklahoma, USA
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Kirin M, Chandra A, Charteris DG, Hayward C, Campbell S, Celap I, Bencic G, Vatavuk Z, Kirac I, Richards AJ, Tenesa A, Snead MP, Fleck BW, Singh J, Harsum S, Maclaren RE, den Hollander AI, Dunlop MG, Hoyng CB, Wright AF, Campbell H, Vitart V, Mitry D. Genome-wide association study identifies genetic risk underlying primary rhegmatogenous retinal detachment. Hum Mol Genet 2013; 22:3174-85. [PMID: 23585552 DOI: 10.1093/hmg/ddt169] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Rhegmatogenous retinal detachment (RRD) is an important cause of vision loss and can potentially lead to blindness. The underlying pathogenesis is complex and incompletely understood. We applied a two-stage genetic association discovery phase followed by a replication phase in a combined total of 2833 RRD cases and 7871 controls. The discovery phase involved a genome-wide association scan of 867 affected individuals and 1953 controls from Scotland, followed by genotyping and testing 4347 highest ranking or candidate single nucleotide polymorphisms (SNPs) in independent sets of cases (1000) and controls (2912) of Dutch and British origin. None of the SNPs selected reached a Bonferroni-corrected threshold for significance (P < 1.27 × 10(-7)). The strongest association, for rs12960119 (P = 1.58 × 10(-7)) located within an intron of the SS18 gene. Further testing was carried out in independent case-control series from London (846 cases) and Croatia (120 cases). The combined meta-analysis identified one association reaching genome-wide significance for rs267738 (OR = 1.29, P = 2.11 × 10(-8)), a missense coding SNP and eQTL for CERS2 encoding the protein ceramide synthase 2. Several of the top signals showing suggestive significance in the combined meta-analysis encompassed genes with a documented role in cell adhesion or migration, including SS18, TIAM1, TSTA3 and LDB2, which warrant further investigation. This first genetic association study of RRD supports a polygenic component underlying RRD risk since 27.4% of the underlying RRD liability could be explained by the collective additive effects of the genotyped SNP from the discovery genome-wide scan.
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Affiliation(s)
- Mirna Kirin
- Centre for Population Health Sciences, University of Edinburgh, Edinburgh EH89AG, UK
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Rajala A, Dilly AK, Rajala RV. Protein tyrosine phosphatase-1B regulates the tyrosine phosphorylation of the adapter Grb2-associated binder 1 (Gab1) in the retina. Cell Commun Signal 2013; 11:20. [PMID: 23521888 PMCID: PMC3637500 DOI: 10.1186/1478-811x-11-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 03/19/2013] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Gab1 (Grb2-associated binder 1) is a key coordinator that belongs to the insulin receptor substrate-1 like family of adaptor molecules and is tyrosine phosphorylated in response to various growth factors, cytokines, and numerous other molecules. Tyrosine phosphorylated Gab1 is able to recruit a number of signaling effectors including PI3K, SHP2 and PLC-γ. In this study, we characterized the localization and regulation of tyrosine phosphorylation of Gab1 in the retina. RESULTS Our immuno localization studies suggest that Gab1 is expressed in rod photoreceptor inner segments. We found that hydrogen peroxide activates the tyrosine phosphorylation of Gab1 ex vivo and hydrogen peroxide has been shown to inhibit the protein tyrosine phosphatase PTP1B activity. We found a stable association between the D181A substrate trap mutant of PTP1B and Gab1. Our studies suggest that PTP1B interacts with Gab1 through Tyrosine 83 and this residue may be the major PTP1B target residue on Gab1. We also found that Gab1 undergoes a light-dependent tyrosine phosphorylation and PTP1B regulates the phosphorylation state of Gab1. Consistent with these observations, we found an enhanced Gab1 tyrosine phosphorylation in PTP1B deficient mice and also in retinas treated ex vivo with a PTP1B specific allosteric inhibitor. CONCLUSIONS Our laboratory has previously reported that retinas deficient of PTP1B are resistant to light damage compared to wild type mice. Since Gab1 is negatively regulated by PTP1B, a part of the retinal neuroprotective effect we have observed previously in PTP1B deficient mice could be contributed by Gab1 as well. In summary, our data suggest that PTP1B regulates the phosphorylation state of retinal Gab1 in vivo.
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Affiliation(s)
- Ammaji Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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Martínez-Palacián A, del Castillo G, Suárez-Causado A, García-Álvaro M, de la Morena-Frutos D, Fernández M, Roncero C, Fabregat I, Herrera B, Sánchez A. Mouse hepatic oval cells require Met-dependent PI3K to impair TGF-β-induced oxidative stress and apoptosis. PLoS One 2013; 8:e53108. [PMID: 23301029 PMCID: PMC3534654 DOI: 10.1371/journal.pone.0053108] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 11/23/2012] [Indexed: 02/07/2023] Open
Abstract
We have previously shown that oval cells harboring a genetically inactivated Met tyrosine kinase (Met−/− oval cells) are more sensitive to TGF-β-induced apoptosis than cells expressing a functional Met (Metflx/flx), demonstrating that the HGF/Met axis plays a pivotal role in oval cell survival. Here, we have examined the mechanism behind this effect and have found that TGF-β induced a mitochondria-dependent apoptotic cell death in Metflx/flx and Met−/− oval cells, associated with a marked increase in levels of the BH3-only proteins Bim and Bmf. Bmf plays a key role during TGF-β-mediated apoptosis since knocking down of BMF significantly diminished the apoptotic response in Met−/− oval cells. TGF-β also induced oxidative stress accompanied by NADPH oxidase 4 (Nox4) mRNA up-regulation and decreased protein levels of antioxidant enzymes. Antioxidants inhibit both TGF-β-induced caspase 3 activity and Bmf up-regulation, revealing an oxidative stress-dependent Bmf regulation by TGF-β. Notably, oxidative stress-related events were strongly amplified in Met−/− oval cells, emphasizing the critical role of Met in promoting survival. Pharmacological inhibition of PI3K did impair HGF-driven protection from TGF-β-induced apoptosis and increased sensitivity of Metflx/flx oval cells to TGF-ß by enhancing oxidative stress, reaching apoptotic indices similar to those obtained in Met−/− oval cells. Interestingly, both PI3K inhibition and/or knockdown itself resulted in caspase-3 activation and loss of viability in Metflx/flx oval cells, whereas no effect was observed in Met−/− oval cells. Altogether, results presented here provide solid evidences that both paracrine and autocrine HGF/Met signaling requires PI3K to promote mouse hepatic oval cell survival against TGF-β-induced oxidative stress and apoptosis.
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Affiliation(s)
- Adoración Martínez-Palacián
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Gaelle del Castillo
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Amileth Suárez-Causado
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - María García-Álvaro
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Diego de la Morena-Frutos
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Margarita Fernández
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Cesáreo Roncero
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Isabel Fabregat
- Laboratori d´Oncologia Molecular and Departament de Ciències Fisiològiques II, Universitat de Barcelona, Institut d´Investigació Biomèdica de Bellvitge, ĹHospitalet de Llobregat, Barcelona, Spain
| | - Blanca Herrera
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Aránzazu Sánchez
- Dep. Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
- * E-mail:
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Lai L, Zhang M, Goldschneider I. Recombinant IL-7/HGFβ efficiently induces transplantable murine hematopoietic stem cells. J Clin Invest 2012; 122:3552-62. [PMID: 22996694 DOI: 10.1172/jci46055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/26/2012] [Indexed: 01/29/2023] Open
Abstract
Difficulty obtaining sufficient hematopoietic stem cells (HSCs) directly from the donor has limited the clinical use of HSC transplantation. Numerous attempts to stimulate the ex vivo growth of purified HSCs with cytokines and growth factors generally have induced only modest increases in HSC numbers while decreasing their in vivo reconstituting ability. We previously developed a recombinant single-chain form of a naturally occurring murine hybrid cytokine of IL-7 and the β chain of hepatocyte growth factor (rIL-7/HGFβ) that stimulates the in vitro proliferation and/or differentiation of common lymphoid progenitors, pre-pro-B cells, and hematopoietic progenitor cells (day 12 spleen colony-forming units) in cultures of mouse BM. Here we used the rIL-7/HGFβ in culture to induce large numbers of HSCs from multiple cell sources, including unseparated BM cells, purified HSCs, CD45- BM cells, and embryonic stem cells. In each instance, most of the HSCs were in the G0 phase of the cell cycle and exhibited reduced oxidative stress, decreased apoptosis, and increased CXCR4 expression. Furthermore, when injected i.v., these HSCs migrated to BM, self-replicated, provided radioprotection, and established long-term hematopoietic reconstitution. These properties were amplified by injection of rIL-7/HGFβ directly into the BM cavity but not by treatment with rIL-7, rHGF, and/or rHGFβ.
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Affiliation(s)
- Laijun Lai
- Department of Immunology, University of Connecticut, Stem Cell Institute, School of Medicine, Health Center, Storrs, CT 06269, USA.
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Ceramide signaling in retinal degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:553-8. [PMID: 22183377 DOI: 10.1007/978-1-4614-0631-0_70] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Retinal degenerations (RD) are a complex heterogeneous group of diseases in which retinal photoreceptors and the supporting retinal pigment epithelial cells die irreversibly, causing visual loss for millions of people. Mutations on more than 150 genes have been discovered for RD and there are many forms that possess complex etiology involving more than one gene and environmental effect. For years many have searched for some common intracellular second messenger for these many forms of cell death which could be targeted for therapy. Ceramide is a novel cellular second messenger which signals for apoptosis. Several lines of evidence suggest an integral role of ceramide in photoreceptor apoptosis and cell death. Understanding their role in the pathogenic pathways of retinal degenerative diseases is important for development of targeted therapeutics.
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Field MG, Yang D, Bian ZM, Petty HR, Elner VM. Retinal flavoprotein fluorescence correlates with mitochondrial stress, apoptosis, and chemokine expression. Exp Eye Res 2011; 93:548-55. [PMID: 21767533 PMCID: PMC3206137 DOI: 10.1016/j.exer.2011.06.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 06/16/2011] [Accepted: 06/28/2011] [Indexed: 12/31/2022]
Abstract
Oxidative stress and mitochondrial dysfunction occur before apoptosis in many retinal diseases. Under these conditions, a larger fraction of flavoproteins become oxidized and, when excited by blue-light, emit green flavoprotein fluorescence (FPF). In this study, we evaluated the utility of FPF as an early indicator of mitochondrial stress, pre-apoptotic cellular instability, and apoptosis of human retinal pigment epithelial (HRPE) cells subjected to hydrogen peroxide (H(2)O(2)) or monocytes (unstimulated or interferon-γ-stimulated) in vitro and of freshly-isolated pieces of human and rat neural retina subjected to H(2)O(2)ex vivo. Increased FPF of HRPE cells exposed to H(2)O(2) correlated with reduced mitochondrial membrane potential (ΔΨm) and increased apoptosis in a time- and dose-dependent manner. HRPE cells co-cultured with monocytes had increased FPF that correlated in a time-dependent manner with reduced ΔΨm, increased apoptosis, and early expression of pro-inflammatory chemokines, interleukin-8 (IL8) and monocyte chemotactic factor-1 (MCP1), which are known to be induced by oxidative stress. Increased FPF, reduced ΔΨm, and upregulation of IL8 and MCP1 occurred as early as 1-2 h after exposure to stressors, while apoptosis did not occur in HRPE cells until later time points. The antioxidant, N-acetyl-cysteine (NAC), inhibited increased FPF and apoptosis of HRPE cells subjected to H(2)O(2). Increased FPF of human and rat neural retina also correlated with increased apoptosis. This study suggests that FPF is a useful measure of mitochondrial function in retinal cells and tissues and can detect early mitochondrial dysfunction that may precede apoptosis.
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Affiliation(s)
- Matthew G. Field
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Dongli Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Zong-Mei Bian
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Howard R. Petty
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan
| | - Victor M. Elner
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
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Jitsanong T, Khanobdee K, Piyachaturawat P, Wongprasert K. Diarylheptanoid 7-(3,4 dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene from Curcuma comosa Roxb. protects retinal pigment epithelial cells against oxidative stress-induced cell death. Toxicol In Vitro 2010; 25:167-76. [PMID: 21044678 DOI: 10.1016/j.tiv.2010.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2010] [Revised: 09/30/2010] [Accepted: 10/26/2010] [Indexed: 09/30/2022]
Abstract
Chronic exposure to oxidative stress causes damage to retinal pigment epithelial cells which may lead to the development of age-related macular degeneration, the major cause of vision loss in humans. Anti-oxidants provide a natural defense against retinal cell damage. The present study was designed to evaluate the potential anti-oxidant activity and protective effect of two diarylheptanoids isolated from a medicinal herb Curcuma comosa; 7-(3,4 dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene (compound A), and 1,7-diphenyl-4(E),6(E)-heptadien-3-ol (compound B) against oxidative stress (H(2)O(2))-induced human retinal pigment epithelial (APRE-19) cell death. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay indicated that the anti-oxidant activity (IC(50)) of compound A was similar to that of vitamin C. Pre-treatment of ARPE-19 cells with 20 μM compound A for 4h afforded greater protection against the insult from 500 μM H(2)O(2), compared to a similar protection period for compound B. Compound A lowered H(2)O(2)-induced lipid peroxidation, malondialdehyde formation and intracellular reactive oxygen species. Furthermore, compound A ameliorated the H(2)O(2)-induced decrease in anti-oxidant enzyme activities and subsequent apoptotic cell death in ARPE-19 cells in a dose and time-dependent manner. These results suggest that compound A protects ARPE-19 cells against oxidative stress, in part, by enhancing several anti-oxidant defense mechanisms. Therefore, compound A may have therapeutic potential for diseases associated with oxidative stress, particularly degenerative retinal diseases.
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Affiliation(s)
- Thunchnok Jitsanong
- Toxicology Graduate Program, Faculty of Science, Mahidol University, Bangkok, Thailand
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30
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Lee HM, Surh BY, Chun YJ. Roles of Neutral Sphingomyelinase 1 on CD95-Mediated Apoptosis in Human Jurkat T Lymphocytes. Biomol Ther (Seoul) 2010. [DOI: 10.4062/biomolther.2010.18.3.262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Rotstein NP, Miranda GE, Abrahan CE, German OL. Regulating survival and development in the retina: key roles for simple sphingolipids. J Lipid Res 2010; 51:1247-62. [PMID: 20100817 PMCID: PMC3035489 DOI: 10.1194/jlr.r003442] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 01/25/2010] [Indexed: 12/28/2022] Open
Abstract
Many sphingolipids have key functions in the regulation of crucial cellular processes. Ceramide (Cer) and sphingosine (Sph) induce growth arrest and cell death in multiple situations of cellular stress. On the contrary, sphingosine-1-phosphate (S1P), the product of Sph phosphorylation, promotes proliferation, differentiation, and survival in different cell systems. This review summarizes the roles of these simple sphingolipids in different tissues and then analyzes their possible functions in the retina. Alterations in proliferation, neovascularization, differentiation, and cell death are critical in major retina diseases and collective evidence points to a role for sphingolipids in these processes. Cer induces inflammation and apoptosis in endothelial and retinal pigmented epithelium cells, leading to several retinopathies. S1P can prevent this death but also promotes cell proliferation that might lead to neovascularization and fibrosis. Recent data support Cer and Sph as crucial mediators in the induction of photoreceptor apoptosis in diverse models of oxidative damage and neurodegeneration, and suggest that regulating their metabolism can prevent this death. New evidence proposes a central role for S1P controlling photoreceptor survival and differentiation. Finally, this review discusses the ability of trophic factors to regulate sphingolipid metabolism and transactivate S1P signaling pathways to control survival and development in retina photoreceptors.
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Affiliation(s)
- Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur-CONICET, Bahía Blanca, Buenos Aires, Argentina.
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32
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Neutrophils compromise retinal pigment epithelial barrier integrity. J Biomed Biotechnol 2010; 2010:289360. [PMID: 20204129 PMCID: PMC2831460 DOI: 10.1155/2010/289360] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 10/15/2009] [Accepted: 11/19/2009] [Indexed: 11/17/2022] Open
Abstract
We hypothesized that neutrophils and their secreted factors mediate breakdown of the integrity of the outer blood-retina-barrier by degrading the apical tight junctions of the retinal pigment epithelium (RPE). The effect of activated neutrophils or neutrophil cell lysate on apparent permeability of bovine RPE-Choroid explants was evaluated by measuring [3H] mannitol flux in a modified Ussing chamber. The expression of matrix metalloproteinase- (MMP-) 9 in murine peritoneal neutrophils, and the effects of neutrophils on RPE tight-junction protein expression were assessed by confocal microscopy and western blot. Our results revealed that basolateral incubation of explants with neutrophils decreased occludin and ZO-1 expression at 1 and 3 hours and increased the permeability of bovine RPE-Choroid explants by >3-fold (P < .05). Similarly, basolateral incubation of explants with neutrophil lysate decreased ZO-1 expression at 1 and 3 hours (P < .05) and increased permeability of explants by 75%. Further, we found that neutrophils prominently express MMP-9 and that incubation of explants with neutrophils in the presence of anti-MMP-9 antibody inhibited the increase in permeability. These data suggest that neutrophil-derived MMP-9 may play an important role in disrupting the integrity of the outer blood-retina barrier.
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Zhu D, Sreekumar PG, Hinton DR, Kannan R. Expression and regulation of enzymes in the ceramide metabolic pathway in human retinal pigment epithelial cells and their relevance to retinal degeneration. Vision Res 2009; 50:643-51. [PMID: 19765607 DOI: 10.1016/j.visres.2009.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 09/06/2009] [Accepted: 09/09/2009] [Indexed: 02/07/2023]
Abstract
Ceramide and its metabolic derivatives are important modulators of cellular apoptosis and proliferation. Dysregulation or imbalance of their metabolic pathways may promote the development of retinal degeneration. The aim of this study was to identify the expression and regulation of key enzymes of the ceramide pathway in retinal pigment epithelial (RPE) cells. RT-PCR was used to screen the enzymes involved in ceramide metabolism that are expressed in RPE. Over-expression of neutral sphingomyelinase-2 (SMPD3) or sphingosine kinase 1 (Sphk1) in ARPE-19 cells was achieved by transient transfection of SMPD3 or Sphk1 cDNA subcloned into an expression vector. The number of apoptotic or proliferating cells was determined using TUNEL and BrdU assays, respectively. Neutral sphingomyelinase-1, neutral sphingomyelinase-2, acidic ceramidase, ceramide kinase, SphK1 and Sphk2 were expressed in both ARPE-19 and early passage human fetal RPE (fRPE) cells, while alkaline ceramidase 2 was only expressed in fRPE cells. Over-expression of SMPD3 decreased RPE cell proliferation and increased cell apoptosis. The percentage of apoptotic cells increased proportionally with the amount of transfected SMPD3 DNA. Over-expression of SphK1 promoted cell proliferation and protected ARPE-19 cells from ceramide-induced apoptosis. The effect of C(2) ceramide on induction of apoptosis was evaluated in polarized vs. non-polarized RPE cultures; polarization of RPE was associated with much reduced apoptosis in response to ceramide. In conclusion, RPE cells possess the synthetic machinery for the production of ceramide, sphingosine, ceramide-1-phosphate (C1P), and sphingosine-1-phosphate (S1P). Over-expression of SMPD3 may increase cellular ceramide levels, leading to enhanced cell death and arrested cell proliferation. The selective induction of apoptosis in non-polarized RPE cultures by C(2) ceramide suggests that increased ceramide levels will preferentially affect non-polarized RPE, as are found in late age-related macular degeneration lesions, and may spare the normal RPE monolayer. SphK1 over-expression increased cellular S1P, which promoted cell proliferation and protected RPE from ceramide-induced apoptosis. Understanding the relationship between the metabolism of sphingolipids and their effects in RPE cell survival/death may help us to develop effective and efficient therapies for retinal degeneration.
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Affiliation(s)
- DanHong Zhu
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, CA 90033, USA
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Chothe PP, Thakkar SV, Gnana-Prakasam JP, Ananth S, Hinton DR, Kannan R, Smith SB, Martin PM, Ganapathy V. Identification of a novel sodium-coupled oligopeptide transporter (SOPT2) in mouse and human retinal pigment epithelial cells. Invest Ophthalmol Vis Sci 2009; 51:413-20. [PMID: 19643969 DOI: 10.1167/iovs.09-4048] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE A sodium-coupled oligopeptide transporter (SOPT1) was described originally in ARPE-19 cells. The transporter is inducible by HIV-1 Tat. Recent studies of conjunctival epithelial cells have identified a second oligopeptide transporter (SOPT2). This study was conducted to determine whether the newly discovered SOPT2 is expressed in ARPE-19 cells, to examine whether the new transporter is also inducible by HIV-1 Tat, and to find out whether this transporter is expressed in primary RPE cells. METHODS The transport activity of SOPT2 was monitored in control and Tat-expressing ARPE-19 cells and in primary mouse and human fetal RPE cells by the uptake of the synthetic opioid peptide DADLE ((H-Tyr-D-Ala-Gly-Phe-D-Leu-OH) and by its susceptibility to inhibition by small peptides. Substrate selectivity was examined by competition studies and kinetic parameters were determined by saturation analysis. RESULTS ARPE-19 cells express DADLE uptake activity that is inhibited by small peptides, indicating expression of SOPT2 in these cells. The activity of SOPT2 is induced by HIV-1 Tat. SOPT2 accepts endogenous and synthetic opioid peptides as substrates, but nonpeptide opiate antagonists are excluded. An 11-amino-acid HIV-1 Tat peptide also serves as a high-affinity substrate for the transporter. Primary cultures of mouse and human fetal RPE cells express SOPT2. The transporter is partially Na(+)-dependent with comparable substrate selectivity and inhibitor specificity in the presence and absence of Na(+). CONCLUSIONS ARPE-19 cells as well as primary mouse and human fetal RPE cells express the newly discovered oligopeptide transporter SOPT2, and the transporter is induced by HIV-1 Tat in ARPE-19 cells.
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Affiliation(s)
- Paresh P Chothe
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia 30912, USA
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35
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Deoxycholate, an endogenous cytotoxin/genotoxin, induces the autophagic stress-survival pathway: implications for colon carcinogenesis. J Toxicol 2009; 2009:785907. [PMID: 20130808 PMCID: PMC2814131 DOI: 10.1155/2009/785907] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 01/25/2009] [Accepted: 02/24/2009] [Indexed: 01/09/2023] Open
Abstract
We report that deoxycholate (DOC), a hydrophobic bile acid associated with a high-fat diet, activates the autophagic pathway in non-cancer colon epithelial cells (NCM-460), and that this activation contributes to cell survival. The DOC-induced increase in autophagy was documented by an increase in autophagic vacuoles (detected using transmission electron microscopy, increased levels of LC3-I and LC3-II (western blotting), an increase in acidic vesicles (fluorescence spectroscopy of monodansycadaverine and lysotracker red probes), and increased expression of the autophagic protein, beclin-1 (immunohistochemistry/western blotting). The DOC-induced increase in beclin-1 expression was ROS-dependent. Rapamycin (activator of autophagy) pre-treatment of NCM-460 cells significantly (P < .05) decreased, and 3-MA (inhibitor of autophagy) significantly (P < .05) increased the cell loss caused by DOC treatment, alone. Rapamycin pre-treatment of the apoptosis-resistant colon cancer cell line, HCT-116RC (developed in our laboratory), resulted in a significant decrease in DOC-induced cell death. Bafilomycin A(1) and hydroxychloroquine (inhibitors of the autophagic process) increased the DOC-induced percentage of apoptotic cells in HCT-116RC cells. It was concluded that the activation of autophagy by DOC has important implications for colon carcinogenesis and for the treatment of colon cancer in conjunction with commonly used chemotherapeutic agents.
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Wang ZY, Shen LJ, Tu L, Hu DN, Liu GY, Zhou ZL, Lin Y, Chen LH, Qu J. Erythropoietin protects retinal pigment epithelial cells from oxidative damage. Free Radic Biol Med 2009; 46:1032-41. [PMID: 19136057 DOI: 10.1016/j.freeradbiomed.2008.11.027] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 10/10/2008] [Accepted: 11/18/2008] [Indexed: 12/17/2022]
Abstract
Oxidative damage from reactive oxygen species (ROS) has been implicated in many diseases, including age-related macular degeneration, in which the retinal pigment epithelium (RPE) is considered a primary target. The aim of this study was to determine whether erythropoietin (EPO) protects cultured human RPE cells against oxidative damage and to identify the pathways that may mediate protection. EPO (1 IU/ml) significantly increased the viability of oxidant-treated RPE cells, decreased the release of the inflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta, recovered the RPE cells' barrier integrity disrupted by oxidative stress, prevented oxidant-induced cell DNA fragmentation and membrane phosphatidylserine exposure, and also reduced the levels of oxidant-induced intracellular ROS and restored cellular antioxidant potential, total antioxidant capacity, glutathione peroxidase, and superoxide dismutase and decreased malondialdehyde, the end product of lipid peroxidation. EPO inhibited caspase-3-like activity. Protection by EPO was partly dependent on the activation of Akt1 and the maintenance of the mitochondrial membrane potential. No enhanced or synergistic protection was observed during application of Z-DEVD-FMK (caspase-3 inhibitor) combined with EPO compared with cultures exposed to EPO and H(2)O(2) alone. Together, these results suggest that EPO could protect against oxidative injury-induced cell death and mitochondrial dysfunction in RPE cells through modulation of Akt1 phosphorylation, mitochondrial membrane potential, and cysteine protease activity.
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Affiliation(s)
- Zhao-yang Wang
- The School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical College, Wenzhou, Zhejiang, China
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37
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Sreekumar PG, Ding Y, Ryan SJ, Kannan R, Hinton DR. Regulation of thioredoxin by ceramide in retinal pigment epithelial cells. Exp Eye Res 2008; 88:410-7. [PMID: 18996115 DOI: 10.1016/j.exer.2008.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 09/16/2008] [Accepted: 10/10/2008] [Indexed: 12/01/2022]
Abstract
The purpose of this study was to determine the expression, regulation and signaling of a key redoxin family member thioredoxin 1 (Trx1) in normal, oxidant-stimulated and growth factor-pretreated RPE cells. Trx1 is expressed in early passage, human RPE cell cultures. RPE cells exposed to C(2)-ceramide for 24h showed no significant change in expression of Trx1 vs. controls with and without pretreatment for 24h with hepatocyte growth factor (HGF). Neither hypoxia from 1% O(2) or from CoCl(2) exposure resulted in any alteration in Trx1 expression in RPE cells. C(2)-ceramide treatment caused translocation of Trx1 from cytosol to the nucleus, which was abolished by pre-treatment of cells with a p38 MAPK-specific inhibitor. Furthermore, the gene and protein expression of thioredoxin interacting protein (Txnip) increased with ceramide treatment and was significantly (p<0.001) elevated with HGF preincubation vs. untreated controls. Prominent protection from ceramide-induced RPE cell death by exogenous rTrx1 was demonstrated. Although Trx1 directly interacts with its inhibitor, Txnip, p38 inhibition does not appear to have a role in this interaction. We found no direct interaction between apoptosis signal regulating kinase (ASK-1) and Txnip under the same experimental conditions. In summary, our data demonstrate the expression of Trx1 and Txnip in human RPE cells. Ceramide treatment results in translocation of Trx1 to the nucleus, and upregulation of Txnip expression; exogenous rTrx1 protects from ceramide-induced cell death. These results suggest that Trx1 and Txnip play an important role in the response of RPE to ceramide toxicity.
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Affiliation(s)
- Parameswaran G Sreekumar
- The Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA
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Petrache I, Medler TR, Richter AT, Kamocki K, Chukwueke U, Zhen L, Gu Y, Adamowicz J, Schweitzer KS, Hubbard WC, Berdyshev EV, Lungarella G, Tuder RM. Superoxide dismutase protects against apoptosis and alveolar enlargement induced by ceramide. Am J Physiol Lung Cell Mol Physiol 2008; 295:L44-53. [PMID: 18441093 DOI: 10.1152/ajplung.00448.2007] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The molecular events leading to emphysema development include generation of oxidative stress and alveolar cell apoptosis. Oxidative stress upregulates ceramides, proapoptotic signaling sphingolipids that trigger further oxidative stress and alveolar space enlargement, as shown in an experimental model of emphysema due to VEGF blockade. As alveolar cell apoptosis and oxidative stress mutually interact to mediate alveolar destruction, we hypothesized that the oxidative stress generated by ceramide is required for its pathogenic effect on lung alveoli. To model the direct lung effects of ceramide, mice received ceramide intratracheally (Cer(12:0) or Cer(8:0); 1 mg/kg) or vehicle. Apoptosis was inhibited with a general caspase inhibitor. Ceramide augmentation shown to mimic levels found in human emphysema lungs increased oxidative stress, and decreased, independently of caspase activation, the lung superoxide dismutase activity at 48 h. In contrast to their wild-type littermates, transgenic mice overexpressing human Cu/Zn SOD were significantly protected from ceramide-induced superoxide production, apoptosis, and air space enlargement. Activation of lung acid sphingomyelinase in response to ceramide treatment was abolished in the Cu/Zn SOD transgenic mice. Since cigarette smoke-induced emphysema in mice is similarly ameliorated by the Cu/Zn SOD overexpression, we hypothesized that cigarette smoke may induce ceramides in the mouse lung. Utilizing tandem mass spectrometry, we documented increased lung ceramides in adult mice exposed to cigarette smoke for 4 wk. In conclusion, ceramide-induced superoxide accumulation in the lung may be a critical step in ceramide's proapoptotic effect in the lung. This work implicates excessive lung ceramides as amplifiers of lung injury through redox-dependent mechanisms.
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Affiliation(s)
- Irina Petrache
- Division of Pulmonary, Allergy, Critical Care, and Occupational Medicine, Indiana University, Indianapolis, Indiana 46202-5120, USA.
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Gómez-Quiroz LE, Factor VM, Kaposi-Novak P, Coulouarn C, Conner EA, Thorgeirsson SS. Hepatocyte-specific c-Met deletion disrupts redox homeostasis and sensitizes to Fas-mediated apoptosis. J Biol Chem 2008; 283:14581-9. [PMID: 18348981 DOI: 10.1074/jbc.m707733200] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The hepatocyte growth factor and its receptor c-Met direct a pleiotropic signal transduction pathway that controls cell survival. We previously demonstrated that mice lacking c-Met (Met-KO) in hepatocytes were hypersensitive to Fas-induced liver injury. In this study, we used primary hepatocytes isolated from Met-KO and control (Cre-Ctrl) mice to address more directly the protective effects of c-Met signaling. Loss of c-Met function increased sensitivity to Fas-mediated apoptosis. Hepatocyte growth factor suppressed apoptosis in Cre-Ctrl but not Met-KO hepatocytes concurrently with up-regulation of NF-kappaB and major antiapoptotic proteins Bcl-2 and Bcl-xL. Intriguingly, Met-KO hepatocytes exhibited intrinsic activation of NF-kappaBas well as Bcl-2 and Bcl-xL. Furthermore, unchallenged Met-KO cells displayed oxidative stress as evidenced by overproduction of reactive oxygen species, which was associated with greater NADPH and Rac1 activities, was blocked by the known NADPH oxidase inhibitors, and was paralleled by increased lipid peroxidation and reduced glutathione (GSH) content. N-Acetylcysteine, an antioxidant and GSH precursor, significantly reduced Jo2-induced cell death. Conversely, the GSH-depleting agent buthionine sulfoximine completely abolished the protective effects of N-acetylcysteine in Met-KO hepatocytes. In conclusion, genetic inactivation of c-Met in mouse hepatocytes caused defects in redox regulation, which may account for the increased sensitivity to Fas-induced apoptosis and adaptive up-regulation of NF-kappaB survival signaling. These data provide evidence that intact c-Met signaling is a critical factor in the protection against excessive generation of endogenous reactive oxygen species.
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Affiliation(s)
- Luis E Gómez-Quiroz
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
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He S, Yaung J, Kim YH, Barron E, Ryan SJ, Hinton DR. Endoplasmic reticulum stress induced by oxidative stress in retinal pigment epithelial cells. Graefes Arch Clin Exp Ophthalmol 2008; 246:677-83. [DOI: 10.1007/s00417-008-0770-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 01/05/2008] [Accepted: 01/10/2008] [Indexed: 01/20/2023] Open
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TAKEO S, TAKAGI N, TAKAGI K. Ischemic Brain Injury and Hepatocyte Growth Factor. YAKUGAKU ZASSHI 2007; 127:1813-23. [DOI: 10.1248/yakushi.127.1813] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Satoshi TAKEO
- Department of Molecular and Cellular Pharmacology, Tokyo University of Pharmacy and Life Sciences
| | - Norio TAKAGI
- Department of Molecular and Cellular Pharmacology, Tokyo University of Pharmacy and Life Sciences
| | - Keiko TAKAGI
- Department of Molecular and Cellular Pharmacology, Tokyo University of Pharmacy and Life Sciences
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42
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Tulasne D, Foveau B. The shadow of death on the MET tyrosine kinase receptor. Cell Death Differ 2007; 15:427-34. [DOI: 10.1038/sj.cdd.4402229] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Abstract
Oxidant stress, induced under a variety of conditions, is known to lead to the molecular reprogramming of the tissue-fixed macrophage. This reprogramming is associated with an altered response to subsequent inflammatory stimuli, such as lipopolysaccharide (LPS), leading to enhanced liberation of proinflammatory chemokines and cytokines. Due to this altered response, dysregulated immunity ensues, leading to the development of clinical syndromes such as multiple organ dysfunction syndrome (MODS). Although the mechanisms responsible for this altered macrophage activity by oxidant stress remains complex and poorly elucidated, it appears, based on recent research, that early and direct alterations within lipid rafts are responsible. This early and direct interaction with lipid rafts by oxidants leads to the mobilization of annexin VI from lipid raft constructs, leading to the release of calcium. This increased cytosolic concentration of this secondary messenger, in turn, results in the activation of calcium-dependent kinases, leading to further alterations in lipid raft lipids and eventually lipid raft proteins. Due to these lipid raft compositional changes, preassembly of receptor complexes occur, leading to enhanced proinflammatory activation. Within this review, the complexity of oxidant-induced reprogramming within the tissue fixed macrophage as currently understood is explained.
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Affiliation(s)
- Joseph Cuschieri
- University of Washington, Department of Surgery, Seattle, Washington 98104, USA.
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44
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Radin NS. Allylic structures in cancer drugs and body metabolites that control cell life and death. Expert Opin Drug Discov 2007; 2:809-21. [DOI: 10.1517/17460441.2.6.809] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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45
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Yang D, Elner SG, Bian ZM, Till GO, Petty HR, Elner VM. Pro-inflammatory cytokines increase reactive oxygen species through mitochondria and NADPH oxidase in cultured RPE cells. Exp Eye Res 2007; 85:462-72. [PMID: 17765224 PMCID: PMC2094037 DOI: 10.1016/j.exer.2007.06.013] [Citation(s) in RCA: 270] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 06/12/2007] [Accepted: 06/18/2007] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS) generated during inflammation are believed to play critical roles in various ocular diseases. However, the underlying mechanisms remain poorly understood. We investigated if pro-inflammatory cytokines, tumor necrosis factor (TNF)-alpha, interleukin-1 beta (IL-1 beta), and interferon-gamma (IFN-gamma), induce ROS in human retinal pigment epithelial (RPE) cells. TNF-alpha, IL-1 beta and IFN-gamma increased both intracellular and extracellular ROS production in a time- and dose-dependent manner. Thenoyltrifluoroacetone (TTFA), an inhibitor of mitochondrial respiratory chain, blocked TNF-alpha- and IFN-gamma-, but not IL-1 beta-induced ROS, whereas other two mitochondrial respiratory chain inhibitors, rotenone and antimycin A, had no effect. NADPH oxidase inhibitor (diphenylene iodinium) abolished the ROS production induced by IL-1 beta or IFN-gamma, but not by TNF-alpha, whereas 6-aminonicotinamide (6AN), an inhibitor of the hexose monophosphate shunt (HMS), had no significant effects on the ROS induced by all three cytokines. ROS scavengers, pyrrolidinedithiocarbamate (PDTC) and N-acetyl-cysteine (NAC), reduced the levels of ROS induced by TNF-alpha, IL-1 beta and IFN-gamma (P<0.05). Collectively, these results demonstrate that TNF-alpha, IL-1 beta and IFN-gamma increase mitochondrial- and NADPH oxidase-generated ROS in human RPE cells.
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Affiliation(s)
- Dongli Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Susan G. Elner
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Zong-Mei Bian
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Gerd O. Till
- Department of Pathology, University of Michigan, Ann Arbor, MI
| | - Howard R. Petty
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI
| | - Victor M. Elner
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
- Department of Pathology, University of Michigan, Ann Arbor, MI
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Morales MC, Pérez-Yarza G, Rementería NN, Boyano MD, Apraiz A, Gómez-Muñoz A, Pérez-Andrés E, Asumendi A. 4-HPR-mediated leukemia cell cytotoxicity is triggered by ceramide-induced mitochondrial oxidative stress and is regulated downstream by Bcl-2. Free Radic Res 2007; 41:591-601. [PMID: 17454142 DOI: 10.1080/10715760701218558] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
We have previously reported that, in leukemia cells, the cytotoxicity of the anticancer agent N-(4-hydroxyphenyl)retinamide (4-HPR) is mediated by mitochondria-derived reactive oxygen species (ROS) and cardiolipin peroxidation. Here, we have analyzed at greater depth the 4-HPR-triggered molecular events, demonstrating that 4-HPR induces an early (15 min) increase in ceramide levels by sphingomyelin hydrolysis and later (from 1 h) by de novo synthesis. Using specific inhibitors of both pathways, we demonstrate that ceramide accumulation is responsible for early ROS generation, which act as apoptotic signalling intermediates leading to conformational activation of Bak and Bax, loss of mitochondrial membrane potential (DeltaPsim), mitochondrial membrane permeabilization (MMP) and cell death. Enforced expression of Bcl-2 has no effect on 4-HPR-induced oxidative stress, but notably prevents mitochondrial alterations and apoptosis, indicating that Bcl-2 functions by regulating events downstream of ROS generation. In conclusion, our study delineates for the fist time the sequence and timing of the principal events induced by 4-HPR in leukemia cells and points to the potential use of modulators of ceramide metabolism as enhancers in 4-HPR-based therapies.
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Affiliation(s)
- Maria-Celia Morales
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, Barrio Sarriena s/n, Leioa, Bizkaia, Spain
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Huber LC, Jüngel A, Distler JHW, Moritz F, Gay RE, Michel BA, Pisetsky DS, Gay S, Distler O. The role of membrane lipids in the induction of macrophage apoptosis by microparticles. Apoptosis 2007; 12:363-74. [PMID: 17191114 DOI: 10.1007/s10495-006-0622-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Microparticles are membrane-derived vesicles that are released from cells during activation or cell death. These particles can serve as mediators of intercellular cross-talk and induce a variety of cellular responses. Previous studies have shown that macrophages undergo apoptosis after phagocytosing microparticles. Here, we have addressed the hypothesis that microparticles trigger this process via lipid pathways. In these experiments, microparticles induced apoptosis in primary macrophage cells or cell lines (RAW 264.7 or U937) with up to a 5-fold increase. Preincubation of macrophages with phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)BP) reduced the microparticle-induced apoptosis in a dose-dependent manner. PtdIns(3,5)BP is a specific inhibitor of the acid sphingomyelinase and thus can block the generation of pro-apoptotic ceramides. Similarly, the pre-incubation of macrophages with PtdIns(3,5)BP prevented microparticle-induced upregulation of caspase 8, which is a major target molecule of ceramide action in the apoptosis pathway. PtdIns(3,5)BP, however, had no effect on the spontaneous rate of apoptosis. To evaluate further signaling pathways induced by microparticles, the extracellular signal regulated kinase (ERK-) 1 was investigated. This kinase plays a role in activating phospholipases A2 which cleaves membrane phospholipids into arachidonic acid; microparticles have been suggested to be a preferred substrate for phospholipases A2. As shown in our experiments, microparticles strongly increased the amount of phosphorylated ERK1/2 in RAW 264.7 macrophages in a time-dependent manner, peaking 15 min after co-incubation. Addition of PD98059, a specific inhibitor of ERK1, prevented the increase in apoptosis of RAW 264.7 macrophages. Together, these data suggest that microparticles perturb lipid homeostasis of macrophages and thereby induce apoptosis. These results emphasize the importance of biolipids in the cellular cross-talk of immune cells. Based on the fact that in clinical situations with excessive cell death such as malignancies, autoimmune diseases and following chemotherapies high levels of circulating microparticles might modulate phagocytosing cells, a suppression of the immune response might occur due to loss of macrophages.
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Affiliation(s)
- Lars C Huber
- Center of Experimental Rheumatology, University Hospital Zurich, Gloriastrasse 23, CH-8091, Zurich, Switzerland.
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Li H, Jiang T, Lin Y, Zhao Z, Zhang N. HGF protects rat mesangial cells from high-glucose-mediated oxidative stress. Am J Nephrol 2006; 26:519-30. [PMID: 17124385 DOI: 10.1159/000097368] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Accepted: 10/24/2006] [Indexed: 01/09/2023]
Abstract
BACKGROUND Oxidative stress has been considered to be a common pathogenetic factor of diabetic nephropathy. Recent observations suggested that hepatocyte growth factor (HGF) was an antioxidant growth factor; thus, its renoprotective effects in diabetic nephropathy might be related to antioxidant mechanism. The aim of the present study was to evaluate whether HGF could prevent rat mesangial cells (RMC) from high-glucose-mediated oxidative stress and explore its relevant mechanism. METHODS RMC were cultured in 5.6 mM (NG) or 30 mM (HG) glucose in the absence or presence of HGF (20 ng/ml) and c-met inhibitor SU11274 (5 microM) for 24 h. RESULTS c-met expression in HG was markedly increased. Enhanced oxidative stress was observed in HG as evidenced by elevated reactive oxygen species and malondialdehyde levels and decreased glutathione level, which was markedly attenuated by HGF. HGF also inhibited HG-induced p22(phox) and aldose reductase upregulation and prevented HG-reduced glutamate-cysteine ligase catalytic subunit (GCLC) expression through inhibiting USF binding to negative regulatory region of GCLC promoter. Reduced glucose-6-phosphate dehydrogenase activity and expression in RMC by HG was rescued by HGF. CONCLUSION HGF could function as an antioxidant factor and protect against HG-mediated oxidative stress by enhancing ROS scavenging and suppressing ROS production.
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Affiliation(s)
- Hui Li
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, PR China
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Xu J, Gao M, Fan S, Meng Q, Goldberg ID, Abounader R, Ressom H, Laterra JJ, Rosen EM. Effect of Akt inhibition on scatter factor-regulated gene expression in DU-145 human prostate cancer cells. Oncogene 2006; 26:2925-38. [PMID: 17099727 DOI: 10.1038/sj.onc.1210088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cytokine scatter factor (SF) (hepatocyte growth factor) transduces various biologic actions, including cell motility, invasion, angiogenesis and apoptosis inhibition. The latter is relevant to understanding the role of SF in promoting tumor cell survival in different contexts, for example, detachment from basement membrane, growth in metastatic sites and responses to chemo- and radiotherapy. Previously, we showed that SF protects cells against apoptosis owing to DNA damage, by a mechanism involving phosphoinositol-3-kinase/c-Akt signaling. Here, we used DNA microarray assays to identify c-Akt-regulated genes that might contribute to cell protection. DU-145 human prostate cancer cells were transfected+/-a dominant-negative mutant Akt, treated+/-SF and analysed for gene expression using Affymetrix arrays. These studies identified SF-regulated genes for which induction was c-Akt-dependent vs -independent. Selected microarray findings were confirmed by semiquantitative and quantitative reverse transcription-polymerase chain reaction. We tested the contribution of four SF-inducible/c-Akt-dependent genes (AMPD3, EPHB2, MX1 and WNT4) to protection against adriamycin (a DNA topoisomerase IIalpha inhibitor) using RNA interference. Knockdown of each gene except EPHB2 caused a small but significant reduction in the SF cell protection. The lack of effect of EPHB2 knockdown may be due to the fact that DU-145 cells contain a single-mutant EPHB2 allele. A combination of three small interfering RNAs blocked most of the protection by SF in both DU-145 and T47D cells. These findings identify novel c-Akt-regulated genes, some of which contribute to SF-mediated cytoprotection.
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Affiliation(s)
- J Xu
- Department of Oncology, Lombardi Comprehensive Cancer Center/Georgetown University, Washington, DC 20057, USA
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Niimura M, Takagi N, Takagi K, Mizutani R, Ishihara N, Matsumoto K, Funakoshi H, Nakamura T, Takeo S. Prevention of apoptosis-inducing factor translocation is a possible mechanism for protective effects of hepatocyte growth factor against neuronal cell death in the hippocampus after transient forebrain ischemia. J Cereb Blood Flow Metab 2006; 26:1354-65. [PMID: 16511502 DOI: 10.1038/sj.jcbfm.9600287] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Hepatocyte growth factor (HGF) is one of the prospective agents for therapy against a variety of neurologic and neurodegenerative disorders, although the precise mechanisms for the effect of HGF remain to be elucidated. We showed that treatment with HGF protected hippocampal cornu ammonis (CA) subregion 1 neurons from apoptotic cell death after transient forebrain ischemia. Accumulating evidence indicates that ischemia-induced neuronal damage occurs via caspase-independent pathways. In the present study, we focused on the localization of apoptosis-inducing factor (AIF), which is an important protein in the signal-transduction system through caspase-independent pathways, to investigate the possible mechanism for the protective effect of HGF after transient forebrain ischemia. Hepatocyte growth factor attenuated the increase in the expression of AIF protein in the nucleus after transient forebrain ischemia. We further explored the upstream components of AIF translocation. Primary DNA damage induced by Ca(2+) influx and subsequent NO formation are thought to be the initial events for AIF translocation, which results in the subsequent DNA damage by AIF. Hepatocyte growth factor prevented the primary oxidative DNA damage, as was estimated by using anti-8-OHdG (8-hydroxy-2'-deoxyguanosine) antibody. Oxidative DNA damage after ischemia is known to lead to the activation of poly(ADP-ribose) polymerase (PARP) and p53, resulting in AIF translocation. Marked increases in the PAR polymer formation and the expression of p53 protein after ischemia were effectively prevented by HGF treatment. In the present study, we first showed that HGF was capable of preventing neuronal cell death by inhibiting the primary oxidative DNA damage and then preventing the activation of the PARP/p53/AIF pathway.
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Affiliation(s)
- Makiko Niimura
- Department of Molecular and Cellular Pharmacology, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo, Japan
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