P38 PKCepsilon-ERK1/2-STAT3 signal pathway contributes to regulation of endogenous hydrogen sulfide for hepatocyte apoptosis induced by lipopolysaccharide

Abstract

The study was designed to elucidate roles of PKCepsilon, ERK1/2, STAT3 in regulations of endogenous H 2 S in rat hepatocyte apoptosis induced by LPS. The cultured rat hepatocytes were treated with vehicle or different dose of LPS respectively. In the separate experiments, hepatocytes were treated with CBS inhibitor AOAA,CSE inhibitor PAG or PKC epsilon, ERK1/2, STAT3 specific inhibitors SCP0213, A6355, S31-201,respectively or in a different combination manner. PKC epsilon, ERK1/2 and STAT3 phospharylations, PKCepsilon membranous translocation, STAT3 nuclear translocation were detected with Western blotting. Apoptosis rates were detected with flow cytometry. PKC epsilon, ERK1/2 and STAT3 phosphorylation expression in LPS-treated hepatocytes were significantly up-regulated, obviously in 30 min compared with vehicle,furthermore membranous tranlocation of PKCepsilon and nuclear tranlocation of STAT3 were found. Compared with LPS, AOAA or PAG combined with LPS respectively or jointly could cause further more obvious up-regulation in phosphorylative levels of PKCepsilon, ERK1/2 or STAT3 protein expression. SCP0213, A6355 or S31-201 combined with LPS respectively could cause increased apoptosis rates in 4 h and 12 h compared with LPS alone. When hepatocytes were treated with SCP0213, A6355 or S31-201 combined with AOAA or PAG respectively, apoptosis rates increased in 12 h but no significant changes in 4 h compared with AOAA or PAG + LPS treatments.Compared with LPS,SCP0213 + LPS could cause down-regulation in phosphorylative levels of ERK1/2 or STAT3 protein expressions, A6355 + LPS could cause down-regulation in the phosphorylative level of STAT3 protein expression without change in PKCepsilon, S31–201 + LPS could not cause any changes of phosphorylative level of protein expression in PKCepsilon or ERK1/2. In conclusion,PKCepsilon-ERK1/2-STAT3 pathway was involved in regulations of endogenous H 2 S for LPS-induced hepatocyte apoptosis.