Function of glutathione peroxidase in endothelial cell vitality

The two human umbilical vein endothelial cell-derived lines, ECRF24 and ECV 304, differ in responsiveness to oxidative stress, In confluent monolayers of ECRF24, but not in ECV304, peroxides induce stress responses such as pla sma membrane blebbing and nuclear condensation. The peroxide effect on ECRF 24 was preceded by oxidation of reduced glutathione (GSH) and of NAD(P)H, a nd by oxidation of the redox-sensitive probe, chloromethyl 2',7'-dichlorofl uorescin (DCFH), In monolayers of ECV304, peroxides induced only minimal ox idation of GSH, NAD(P)H and DCFH, which was associated with a greatly reduc ed GSH peroxidase activity in these cells. However, in spite of the absence of a blebbing response, ECV304 were more susceptible than ECRF24 to membra ne lipid peroxidation and peroxide-induced necrosis, Only for ECV304, the c ulturing with high levels of polyunsaturated fatty acids increased lipid pe roxidation and cellular death. Treatment of these cells with the GSH peroxi dase mimic ebselen effectively reversed their decreased vitality. We conclu de that, in peroxide-treated endothelial cells, cell death (necrosis) can r esult from lipid peroxidation by peroxide that has not been removed by GSH peroxidases, whereas extensive peroxidase activity may cause a stress respo nse (blebbing), The data further identify ECV304 as a stress-sensitive cell line, where peroxides exert their effects independently of GSH oxidation, (C) 2000 Academic Press.