Peroxiredoxin 1 inhibits the oxidative stress induced apoptosis in renal tubulointerstitial fibrosis.

ABSTRACT

AIM: Apoptosis is one of the most important mechanisms underlying renal tubulointerstitial fibrosis. We identified a role of protein Peroxiredoxin 1 (Prx1) in protecting apoptosis occurred in tubular epithelial cells of the rat and human kidney. METHODS: Immunohistochemistry (IHC) staining was used to detect Prx1 expression in kidney derived from unilateral-ureteral obstruction (UUO) rats or patients with obstructive nephropathy. Modulation of Prx1 expression by transfecting siRNA and overexpression plasmid approach were carried out in NRK-52E (rat kidney tubular epithelial cell line) cells. UUO-induced apoptosis was determined using TUNEL assay. RESULTS: Immunohistochemistry staining showed that Prx1 expressed in the cytoplasm of renal tubular epithelial cells, in the kidneys of UUO rats. The reduction was confirmed by both IHC and real-time polymerase chain reaction following a course of renal tubulointerstitial fibrosis in UUO rats and a decrease of Prx1 occurred concomitantly with an elevation of TUNEL-positive cells. Fluorofenidone (AKF-PD), a new anti-tubulointerstitial fibrotic agent, attenuated Prx1 reduction in UUO rats. Furthermore, hydrogen peroxide (H2 O2 )-derived oxidative stress activated p38 MAPK, and induced apoptosis in NRK-52E cells; knockdown of Prx1 sensitized both events in NRK-52E cells, and overexpression of Prx1 diminished the apoptosis and the phosphorylation of p38 CONCLUSION: Downregulation of Prx1 occurred in renal tubular epithelial cells of UUO rats and patients with obstructive nephropathy. Prx1 may alleviate the pathogenesis by inhibiting H2 O2 -induced apoptosis via inhibiting the p38 MAPK pathway. Prx1 may represent a useful target for a protective therapy towards renal tubulointerstitial fibrosis.