Sublethal Versus Lethal Hydrogen Peroxide-Induced Injury To Renal Epithelial Cells: Roles Of Tight Junction Proteins

Hydrogen peroxide (H2O2) treatment of renal epithelial cells is a model for renal ischemia-reperfusion injury. Lethal, but not sublethal H2O2 caused collapse of domes in confluent MDCK cell populations. H2O2 produced a concentration-dependent increase in paracellular calcein movement across confluent MDCK cell populations. In contrast, TransEpithelial Resistance was only decreased by lethal concentrations of H2O2. The cellular contents of tight junction proteins, occludin, ZO-1 and ZO-2, were not altered by treatment with either sublethal or lethal H2O2 concentrations. H2O2 produced a concentration-dependent decrease in basal F-actin stress fibers. Sublethal H2O2 did not alter the localization of occludin, ZO-1 or ZO-2 but localization was affected modestly by lethal H2O2. Knockdown of either occludin or ZO-2 increased the sensitivity of MDCK cells to H2O2-induced injury. In contrast, knockdown of ZO-1 or overexpression of occludin decreased MDCK cell sensitivity to H2O2. These results indicate that occlu...