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Triamcinolone acetonide prevents oxidative stress-induced tight junction disruption of retinal pigment epithelial cells. Graefes Arch Clin Exp Ophthalmol 2009; 247:641-9. [PMID: 19189116 DOI: 10.1007/s00417-009-1041-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 12/23/2008] [Accepted: 01/12/2009] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Oxidative stress is known to disrupt the integrity of retinal pigment epithelium (RPE) tight junctions. The goal of this study is to evaluate the effect of triamcinolone acetonide (TA) on the junctional integrity of RPE under oxidative stress and to identify the underlying mechanisms. METHODS Second passage porcine RPE cells were cultured on 6-well membrane inserts until 4 weeks after reaching confluence. Cells were incubated with TA (10(-5) M) for 30 min. FITC-containing medium was added to the upper chamber (cell's apical side). The cells were then challenged with 1 mM Hydrogen Peroxide (H(2)O(2)). After 5 h, the fluorescence intensity of the medium from lower chamber (cell's basolateral side) was measured using a fluorescence spectrofluorophotometer. This transepithelial flux of FITC-dextran was measured until the 21st day. The immunolocalization of occludin and F-actin was examined with fluorescence microscope. Reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio was determined by a colorimetric assay kit. RESULTS Non-lethal oxidative stress by H(2)O(2) increased transepithelial flux of FITC-dextran significantly. TA inhibited this increase and preserved the lower flux through the whole experimental period. This permeability change by H(2)O(2) was reversible and recovered to the normal level within 3 weeks. In immunohistological study, H(2)O(2) reduced linear occludin staining at the cell border and increased actin stress fibers. TA prevented H(2)O(2)-induced disruption of junctional assembly of occludin and F-actin. Glutathione assay demonstrated that intracellular GSH/GSSG ratio decreased significantly with H(2)O(2), while TA preserved this ratio by up-regulating GSH synthesis. CONCLUSIONS TA has a protective effect against oxidative stress-induced disruption of RPE tight junction by preserving cellular redox state.
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Wong CG, Bonakdar M, Kleinman MT, Chow J, Bhalla DK. Elevation of Stress-Inducible Heat Shock Protein 70 in the Rat Lung After Exposure to Ozone and Particle-Containing Atmospheres. Inhal Toxicol 2008. [DOI: 10.3109/08958379409040507] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bonakdar M, Rasmussen RE, Wong CG. Lack Of Effect On Rat Lung Stress-Inducible Heat Shock Protein 70 After Acute Tobacco Smoke Inhalation. Inhal Toxicol 2008. [DOI: 10.3109/08958379509029707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Wong CG, Rasmussen RE, Bonakdar M. Lack of Elevation of Stress-Inducible Heat-Shock Protein 70 in the Ferret Lung After Chronic Cigarette Smoke Inhalation. Inhal Toxicol 2008. [DOI: 10.3109/08958379509012811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Liang FQ, Alssadi R, Morehead P, Awasthi YC, Godley BF. Enhanced expression of glutathione-S-transferase A1-1 protects against oxidative stress in human retinal pigment epithelial cells. Exp Eye Res 2005; 80:113-9. [PMID: 15652532 DOI: 10.1016/j.exer.2004.08.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Accepted: 08/18/2004] [Indexed: 10/26/2022]
Abstract
Glutathione-S-transferases (GSTs) play an important role in protection mechanisms against oxidative stress. We sought to determine whether over-expression of human GSTA1-1 in RPE cells is able to attenuate H(2)O(2)-induced oxidative stress. SV40-transformed human fetal RPE cells were stably transfected with pRC/hGSTA1-1 vector which carries a full-length of human GSTA1-1 cDNA. The control RPE cells were either non-transfected or transfected with control vector pRC. Expression of hGSTA1-1 protein in these cells was confirmed by Western blot and immunocytochemical analyses. The protective effects of hGSTA1-1 on cell viability and mitochondrial DNA (mtDNA) damage caused by H(2)O(2) were examined with MTT assay and quantitative PCR (QPCR), respectively. The hGSTA1-1 transfected RPE cells exhibited a similar morphology and growth rate as control RPE cells. Immunocytochemical analysis showed robust expression hGSTA1-1 in hGSTA1-1 transfected cells versus background staining in control cells. Western blotting of protein extracts from cells transfected with hGSTA1-1 revealed a 26 kDa protein band which corresponds to the size of recombinant mature hGSTA1-1. The active GST present in the hGSTA1-1 transfected cells was approximately three times higher than in control cells. The MTT assay showed a significantly greater viability of hGSTA1-1 cells in response to H(2)O(2) (100 and 200 microm) compared to control cells (p<0.05). QPCR indicated that mtDNA damage was significantly decreased in hGSTA1-1 cells than in control cells (p<0.05). Human GSTA1-1 transfection protect against RPE cell death and mtDNA damage caused by H(2)O(2), suggesting an important role of GST in protection against oxidative stress in RPE cells.
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Affiliation(s)
- Fong-Qi Liang
- Retina Foundation of the Southwest, 9900 N. Central Expressway, Suite 400, Dallas, TX 75231, USA
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Kamaruddin M, Kroetsch T, Basrur PK, Hansen PJ, King WA. Immunolocalization of heat shock protein 70 in bovine spermatozoa. Andrologia 2004; 36:327-34. [PMID: 15458553 DOI: 10.1111/j.1439-0272.2004.00629.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Heat shock protein 70 (HSP70) is part of a superfamily of molecular chaperones, which protect cells from chemical and heat shock. The objectives of this study were to determine the presence of HSP70 in bovine spermatozoa and its subcellular localization during different stages of spermatogenesis. Analysis of sperm proteins by Western blotting using a monoclonal antibody to the inducible form of HSP70 revealed a single immunoreactive band with an estimated molecular weight of 70 kDa in samples from 18 of 18 bulls. Using immunofluorescence microscopy and the same antibody, HSP70 was localized to the cytoplasm of prophase spermatocytes and elongating spermatids, to cytoplasmic droplets of caput epididymal spermatozoa, and to cytoplasmic droplets, acrosome, post-acrosomal region and middle piece of corpus and cauda epididymal spermatozoa. The pattern of distribution changed in freshly ejaculated spermatozoa as HSP70 was detected on the acrosome only. During capacitation and acrosome reaction, HSP70 was once again redistributed, and was localized to the equatorial segment, post-acrosomal region and middle piece. Thus, HSP70 is present in the spermatozoa of mature bulls and redistribution of the protein occurs during capacitation and the acrosome reaction.
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Affiliation(s)
- M Kamaruddin
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Godley BF, Jin GF, Guo YS, Hurst JS. Bcl-2 overexpression increases survival in human retinal pigment epithelial cells exposed to H(2)O(2). Exp Eye Res 2002; 74:663-9. [PMID: 12126940 DOI: 10.1006/exer.2001.1146] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The integrity of the retinal pigment epithelium, especially that of the macula is essential for the preservation of vision into old age. The chronic exposure to sunlight and peroxidized lipids from phagocytized photoreceptor outer segments imposes a high level of oxidative stress on the retinal tissues, which increases with age as antioxidant protection declines and therefore could accelerate apoptosis. Bcl-2 known to facilitate mitochondrial DNA repair and cellular survival in other tissues was overexpressed in a single clone of human retinal pigment epithelium cells after stable transfection with humanbcl-2 in rhoSFV-neoexpression factor. Near confluent cells (2nd-4th generation permanently bcl-2 transfected) were protected from mitochondrial dysfunction after exposure to H(2)O(2) up to 150 microM. With 200 microM H(2)O(2), function in transfected cells declined by only 25% control activity as determined by MTT reduction assays, compared to wild type and vector only transfected cells expressing normal bcl-2 levels. Similarly the bcl-2 -transfected cells were more resistant to mitochondrial DNA damage after H(2)O(2) treatment than the other groups and suffered 50% less damage after exposure to 200 microM H(2)O(2), as assayed by quantitative polymerase chain reaction assays. These data suggest that bcl-2 overexpression protects human RPE cells from mitochondrial respiratory dysfuction, mitochondrial DNA damage and promotes cellular survival in response to oxidative stress induced by H(2)O(2).
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Cheng JZ, Sharma R, Yang Y, Singhal SS, Sharma A, Saini MK, Singh SV, Zimniak P, Awasthi S, Awasthi YC. Accelerated metabolism and exclusion of 4-hydroxynonenal through induction of RLIP76 and hGST5.8 is an early adaptive response of cells to heat and oxidative stress. J Biol Chem 2001; 276:41213-23. [PMID: 11522795 DOI: 10.1074/jbc.m106838200] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To explore the role of lipid peroxidation (LPO) products in the initial phase of stress mediated signaling, we studied the effect of mild, transient oxidative or heat stress on parameters that regulate the cellular concentration of 4-hydroxynonenal (4-HNE). When K562 cells were exposed to mild heat shock (42 degrees C, 30 min) or oxidative stress (50 microM H2O2, 20 min) and allowed to recover for 2 h, there was a severalfold induction of hGST5.8, which catalyzes the formation of glutathione-4-HNE conjugate (GS-HNE), and RLIP76, which mediates the transport of GS-HNE from cells (Awasthi, S., Cheng, J., Singhal, S. S., Saini, M. K., Pandya, U., Pikula, S., Bandorowicz-Pikula, J., Singh, S. V., Zimniak, P., and Awasthi, Y. C. (2000) Biochemistry 39, 9327-9334). Enhanced LPO was observed in stressed cells, but the major antioxidant enzymes and HSP70 remained unaffected. The stressed cells showed higher GS-HNE-conjugating activity and increased efflux of GS-HNE. Stress-pre-conditioned cells with induced hGST5.8 and RLIP76 acquired resistance to 4-HNE and H2O2-mediated apoptosis by suppressing a sustained activation of c-Jun N-terminal kinase and caspase 3. The protective effect of stress pre-conditioning against apoptosis was abrogated by coating the cells with anti-RLIP76 IgG, which inhibited the efflux of GS-HNE from cells, indicating that the cells acquired resistance to apoptosis by metabolizing and excluding 4-HNE at a higher rate. Induction of hGST5.8 and RLIP76 by mild, transient stress and the resulting resistance of stress-pre-conditioned cells to apoptosis appears to be a general phenomenon since it was not limited to K562 cells but was also evident in lung cancer cells, H-69, H-226, human leukemia cells, HL-60, and human retinal pigmented epithelial cells. These results strongly suggest a role of LPO products, particularly 4-HNE, in the initial phase of stress mediated signaling.
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Affiliation(s)
- J Z Cheng
- Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, Texas 77555-1067, USA
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Ballinger SW, Van Houten B, Jin GF, Conklin CA, Godley BF. Hydrogen peroxide causes significant mitochondrial DNA damage in human RPE cells. Exp Eye Res 1999; 68:765-72. [PMID: 10375440 DOI: 10.1006/exer.1998.0661] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retinal pigment epithelial cell dysfunction mediated by reactive oxygen intermediates has been suggested as a possible cause of age-related macular degeneration. To test the hypothesis that retinal pigment cells are susceptible to genetic damage mediated by reactive oxygen intermediates, retinal pigment epithelial cells were treated with 50 micrometers-200 micrometers of hydrogen peroxide in vitro. Damage to mitochondrial DNA and three nuclear loci were assessed using quantitative polymerase chain reaction. Hydrogen peroxide treatment of retinal pigment epithelial cells resulted in significantly increased mitochondrial DNA damage. Significant mitochondrial DNA damage occurred rapidly and was not completely repaired within 3 hr post-treatment. By contrast, no DNA damage was observed in three different nuclear loci (beta-globin gene cluster, hprt, and beta- polymerase genes). Hydrogen peroxide treatment of retinal pigment epithelial cells also resulted in decreased mitochondrial redox function compared to controls, consistent with increased mitochondrial DNA damage. Consequently, retinal pigment epithelial cell mitochondrial DNA appears susceptible to hydrogen peroxide mediated damage in vitro, and thus, may serve as a catalyst in the initial events leading to retinal pigment epithelial cell dysfunction in vivo.
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Affiliation(s)
- S W Ballinger
- Sealy Center for Molecular Cardiology, University of Texas Medical Branch, Galveston, TX, 77555, USA
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Hackett SF, Schoenfeld CL, Freund J, Gottsch JD, Bhargave S, Campochiaro PA. Neurotrophic factors, cytokines and stress increase expression of basic fibroblast growth factor in retinal pigmented epithelial cells. Exp Eye Res 1997; 64:865-73. [PMID: 9301467 DOI: 10.1006/exer.1996.0256] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Basic fibroblast growth factor (bFGF) and FGF receptors have been localized to photoreceptors and retinal pigmented epithelium (RPE), but the function of bFGF in adult retina and RPE is unknown. Exogenous bFGF has a neuroprotective effect in retina and brain and its expression is increased in some neurons in response to cytokines or stress. In this study, we investigated the effect of light, other types of stress, neurotrophic factors, and cytokines on bFGF levels in cultured human RPE. Some agents that protect photoreceptors from the damaging effects of constant light, including brainderived neurotrophic factor (BDNF), ciliary neurotrophic factor, and interleukin-1 beta, increase bFGF mRNA levels in RPE cells. Intense light and exposure to oxidizing agents also increase bFGF mRNA levels in RPE cells and cycloheximide blocks the increase. An increase in bFGF protein levels was demonstrated by ELISA in RPE cell supernatants after incubation with BDNF or exposure to intense light or oxidizing agents. These data indicate that bFGF is modulated in RPE cells by stress and by agents that provide protection from stress and support the hypothesis that bFGF functions as a survival factor in the outer retina.
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Affiliation(s)
- S F Hackett
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA
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Kumaki N, Anderson DM, Cosman D, Kumaki S. Expression of interleukin-15 and its receptor by human fetal retinal pigment epithelial cells. Curr Eye Res 1996; 15:876-82. [PMID: 8921231 DOI: 10.3109/02713689609017629] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE IL-15 and IL-15 receptor expression was measured in retinal pigment epithelial (RPE) cells to support a possible role of IL-15 in ocular inflammatory and immune responses. METHODS Reverse transcription-coupled polymerase chain reaction (RT-PCR) and Northern blot analysis of IL-15 mRNA in previously characterized non-transformed and simian virus (SV)-40 transformed human fetal RPE cells were carried out. Biological activities of IL-15 produced by the RPE cells were assayed by co-culture with IL-15 responsive cells. Expression of the IL-15 receptor (IL-15R) alpha, IL-2R beta and gamma chains were examined by RT-PCR. RESULTS Both non-transformed and SV-40 transformed human fetal RPE cells express IL-15, a T cell growth factor which has similar biological activities to IL-2, and the expression of IL-15 is enhanced by interferon-gamma (IFN-gamma) or tumor necrosis factor-alpha (TNF-alpha) stimulation. In addition, transcripts for all three IL-15 receptor components (IL-15R alpha, IL-2R beta and IL-2R gamma) were detected in these cells. CONCLUSIONS RPE cells produce IL-15, which may play an important role in ocular immune and inflammatory responses by stimulating infiltrated T cells and RPE cells via paracrine and autocrine loops, respectively.
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Affiliation(s)
- N Kumaki
- Department of Ophthalmology, Tohoku University School of Medicine, Sendai, Japan
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Wong CG, Bonakdar M, Mautz WJ, Kleinman MT. Chronic inhalation exposure to ozone and nitric acid elevates stress-inducible heat shock protein 70 in the rat lung. Toxicology 1996; 107:111-9. [PMID: 8599170 DOI: 10.1016/0300-483x(95)03250-j] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The ability of urban oxidant and acid air pollutants to induce heat shock proteins (HSPs) in the mammalian lung is not known. Such proteins are known to be correlated with environmental stress and pathophysiological conditions. In this study, stress-inducible HSP 70 was assessed by slot-blotting in rat lungs (N=10 per group) following inhalation exposures for 4 h per day, 3 days per week for 40 weeks to the following pollutants: (a) purified air;(b) 0.15 ppm ozone (O3);(c)50 micrograms/m3 nitric acid (HNO3); or(d) a combination of both 0.15 ppm O3 and 50 micrograms/m3 HNO3. At 24 h following the last exposure, samples from the right apical lobe of the lung were obtained for either slot-blotting or gel electrophoretic separation, subsequent protein immunoblotting, and chemiluminescence detection of HSP 70 levels. Experiments demonstrate that stress-inducible HSP 70 was present constitutively in the control lungs and was separable from the constitutive form of HSP 70. Slot-blotting analysis demonstrate that the O3 and HNO3 exposures alone produced significant elevations of HSP70. Specifically, either O3 or HNO3 alone significantly elevated lung stress-inducible HSP 70 levels by 277% and 221% respectively, above control levels. The group exposed to combined O3 and HNO3 showed a 177% elevation in lung stress-inducible HSP 70 that was significantly greater that the group inhaling purified air, but this effect was less than the effects of either pollutant component alone. Moreover, all exposure groups were significantly different from one another. These results indicate that stress-inducible HSP 70 in the rat lung is highly elevated after chronic inhalation exposures to both O3 and HNO3 when administered either alone or in combination within the range of urban ambient concentrations.
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Affiliation(s)
- C G Wong
- Center for Occupational and Environmental Health, Irvine College of Medicine, University of California 92717, USA
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Sippy BD, Hofman FM, He S, Osusky R, Sheu SJ, Walker SM, Ryan SJ, Hinton DR. SV40-immortalized and primary cultured human retinal pigment epithelial cells share similar patterns of cytokine-receptor expression and cytokine responsiveness. Curr Eye Res 1995; 14:495-503. [PMID: 7545567 DOI: 10.3109/02713689509003761] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Retinal pigment epithelial (RPE) cells produce and respond to a variety of cytokines; however, molecular and biochemical studies are restricted by the limited access to large numbers of pure cells and the variability associated with different donor sources. Despite success in establishing primary human RPE (HRPE) cell cultures, the inability to sustain consistent proliferation rates and morphology over several passages remains a concern. This problem was approached by using an immortalized line of simian virus (SV)40 transformed fetal HRPE cells (SVRPE). Cytokine production, receptor expression and responsiveness in the SVRPE cell line was analyzed to determine the usefulness of this model for studying HRPE-cytokine interactions. Using reverse transcriptase polymerase chain reaction (RT-PCR), HRPE and SVRPE cells demonstrated an identical pattern of interleukin-1 receptor (IL-1R), IL-2R (alpha sub-unit), IL-6R, interferon (IFN)-gamma R and tumor necrosis factor-alpha (TNF)R p55 expression. No amplification products for TNFR p75 or granulocyte/macrophage colony stimulating factor (GM-CSF)R were demonstrated in either population. IFN-gamma stimulation induced surface human leukocyte antigen (HLA)-DR in both SVRPE and HRPE, while TNF treatment induced surface expression of intercellular adhesion molecule (ICAM)-1 on SVRPE and upregulated ICAM from basal levels on HRPE. Both cell types showed amplification products for interleukin (IL)-1 beta, IL-6 and transforming growth factor (TGF)-beta 1 using RT-PCR. The bioassays demonstrated that both populations of unstimulated cells constitutively secrete very low levels of TGF-beta and no IL-6.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- B D Sippy
- Department of Pathology, University of Southern California School of Medicine, Los Angeles 90033, USA
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Yu HS, Hernandez V, Haywood M, Wong CG. Melatonin inhibits the proliferation of retinal pigment epithelial (RPE) cells in vitro. In Vitro Cell Dev Biol Anim 1993; 29A:415-8. [PMID: 8390974 DOI: 10.1007/bf02633991] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The possible antiproliferative effect of melatonin on retinal pigment epithelial (RPE) cells in vitro was investigated. Bovine RPE cells cultured in Ham's F12 medium supplemented with 10% fetal bovine serum had a nuclear density of 73.6 +/- 6.1 nuclei/mm2 at 72 h after seeding. The nuclear density at this time-point was doubled if either 50 or 100 ng/ml human epidermal growth factors (hEGF) was added to the culture medium. When these hEGF-stimulated cells were treated with melatonin from 10 to 500 pg/ml, the proliferation was suppressed with a dose-response relationship. At 250 and 500 pg/ml melatonin, the nuclear densities of the melatonin-treated cells were similar to those of the control cells. Using mitotically active SV-40 transformed human fetal RPE cells cultured in a serum-free medium, melatonin was also shown to be antiproliferative. In the presence of 500 pg/ml melatonin, the proliferation of these cells was inhibited to 77% as compared to the control. These results were further supported by the reduced [H3]thymidine uptake in the melatonin-treated cells. We propose that melatonin, at physiologic concentrations, has an antiproliferative effect, and that cultured RPE cells stimulated to proliferate by either hEGF treatment or SV-40 transfection are responsive to melatonin. Melatonin may either inhibit mitosis in actively dividing cells or modulate hEGF action.
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Affiliation(s)
- H S Yu
- Biorhythm Research Laboratory, University of Texas, San Antonio 78249
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