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Naoko Kato, Miyuki Kubota, Hideyuki Miyashita, Tetsuya Kawakita, Satoru Yoshida, Kazuo Tsubota, Shigeto Shimmura; The Role Of P38 Mapk Phosphorylated Activation By Reactive Oxygen Species In Corneal Epithelial Cells. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4793.
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© ARVO (1962-2015); The Authors (2016-present)
Corneal epithelial cells are highly exposed to sunlight (ultraviolet-A), producing reactive oxygen species. We previously reported p38 MAPK in cultured corneal epithelial cells was phosphorylated by ultraviolet-A (UVA) irradiation (Kato et al, 2010 ARVO meeting). We speculated that p38 phosphorylation in corneal epithelial cells was caused by reactive oxygen species produced within the cells. In the present invesigation, we assessed the major roles of phosphrylated p38 in the corneal epithelial cells.
TKE2 cells (mouse corneal epithelial cell line) were cultured in 5% CO2 at 37°C using the defined KSFM medium, and were irradiated by UVA (370 nm). Reactive oxygen species in TKE cells were measured with fluorescein intensity of 2',7'- dichlorofluorescein, and cell viability was counted by WST-1 assay. The expression of phosphorylated p38, snail, caspase 3, E-cadherin, b-catenin were assessed by RT-PCR, western blotting, and immunofluorescein.
TKE2 cells that exposed by UVA revealed upregulation of reactive oxygen species. P38 was phosphorylated, membrane staining of E-cadherin and b-catenin was decreased, and expression of snail was increased, when the cells were exposed by UVA. Cell viability was not affected by UVA irradiation sorelyalone, but was significantly decreased when SB202190, an inhibitor of p38 was added before the UVA irradiation. In these Cells treated with both SB202190 added and UVA exposed exposurecells, the expression of caspase 3 was observedupregulated.
UVA irradiation caused phosphorylation of p38 via production of intrinsic reactive oxygen species in corneal epithelial cells. The activation of p38 seems to protect corneal epithelial cells from apoptosis, simultaneously causing the phenotypical shift from epithelial to mesenchymal characters of corneal epithelial cells.
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