Inhibition of c-Jun N-Terminal Kinase Ameliorates Apoptosis Induced by Hydrogen Peroxide in the Kidney Tubule Epithelial Cells (NRK-52E)

Abstract

Background: Hydrogen peroxide (H₂O₂)-induced apoptosis has been shown to be involved in ischemic and toxic tubular damage. Recent studies have revealed that oxidative stress can activate c-Jun N-terminal kinase (JNK), and the oxidative stress-JNK pathway is an important apoptotic pathway of cells exposed to various stresses. The present study was designed to investigate JNK activation and the effects of the JNK pathway inhibition during H₂O₂-induced apoptosis in kidney epithelial tubule cells (NRK-52E). Materials and Methods: NRK-52E cells were treated with 0–500 µ M H₂O₂ and/or 100 µ M quercetin (an inhibitor of the JNK pathway). Apoptosis was assessed by flow cytometry analysis and DNA ladder. JNK activity was assessed by the GST-c-Jun (1-169) binding/protein kinase assay. Results: H₂O₂ induced apoptosis in NRK-52E cells in a concentration-dependent manner, which was demonstrated by the reduced DNA PI staining, externalization of phosphatidylserine and DNA ladder. Apoptosis induced by H₂O₂was accompanied by JNK activation and up-regulated JNK activity. Quercetin treatment suppressed the JNK activity and ameliorated apoptosis induced by H₂O₂. Conclusions: H₂O₂ induced apoptosis in NRK-52E cells, which was associated with activation and up-regulation of JNK. Quercetin treatment could decrease JNK activity and ameliorate H₂O₂-induced apoptosis.