Effects of gene associated with retinoid-interferon-induced mortality-19 on ultraviolet A radiation-induced human lens epithelial cell apoptosis in vitro / 中华实验眼科杂志

ABSTRACT

Background Ultraviolet irradiation promotes cellular apoptosis by affecting the mitochondrial transmembrane potential,including human lens epithelial cells (LECs).Gene associated with retinoid-interferoninduced mortality-19 (GRIM-19),a cell death regulatory protein,is essential for the assembly and function of mitochondrial complex Ⅰ.However,whether LECs apoptosis induced by ultraviolet irradiation is related to GRIM-19 is still unclear.Objective The purpose of this study was to investigate the relationship between the apoptosis of human LECs caused by ultraviolet with GRIM-19 expression in vitro.Methods Human LEC line(SRA01/04)was cultured in α-MEM containing 10％ fetal bovine serum.The cells were exposed to ultraviolet ray at doses of 0,30,60,90,120 or 150 mJ/cm2 when cell growth reached the logarithmic phase and 80％ confluency.The rate of apoptosis of the cells was assayed using flow cytometry,and the level of expression and relative amount of GRIM-19 protein (GRIM-19/β-actin) were detected by Western blot.The relationship between apoptosis and the GRIM-19/β-actin value among the different treatment groups was compared using One-way ANOVA,and the correlation of LECs apoptosis rate and GRIM-19 expression level was assessed by Pearson linear analysis.Results A significant difference was found in the apoptosis rate among the different treatment groups(F=149.32,P＜0.01).Compared with the 0 mJ/cm2 ultraviolet irradiation group,the apoptosis rate of LECs was significantly increased in the 60,90,120 and 150 mJ/cm2 ultraviolet irradiation groups (q =17.02,-25.20,-29.41,-8.61,P ＜ 0.01).The expression of the GRIM-19 protein in the LECs suspension was enhanced by ultraviolet irradiation at 60,90,120 and 150 mJ/cm2.The relative expression of the GRIM-19 protein (GRIM-19/β-actin) was significantly different among the various groups (F=6.87,P＜0.05),and the GRIM-19/β-actin values in the 60,90,120,150 mJ/cm2 ultraviolet irradiation groups were elevated in comparison with the un-irradiated group(2.01±0.76,2.98± 1.80,3.97± 1.61,2.42± 1.28 vs.0.56±0.23),which showed statistically significant differences (q =4.12,-5.04,-7.09,-3.85,P ＜ 0.01).In addition,a positive correlation was seen between the rate of apoptosis and the expression of the GRIM-19 protein(r=0.71,P＜0.01).Conclusions GRIM-19 is expressed in normal human LECs.The apoptosis of human LECs accompanies the up-regulation of GRIM-19.The expression of GRIM-19 in LECs increases with ultraviolet irradiation in a doseindependent manner.