Protein expression and phosphorylation of mitogen-acttvated protein kinases in murine kupffer cells induced by lipopolysiaccharide (LPS)

To elucidate the signal transduction mechanism of systemic inflammatory response syndrome induced by LPS, Western blot analysis was used to assay the protein expression and phosphorylation levels of ERI, JNK, and p38 MAPK in murine KC which were stimulated by LPS. It was found that LPS treatment resulted in no significant change in their protein expression, but a rapid transient increase in their phosphorylation levels, which peaked at 30, 45, and 20 minutes, respectively; The values returned to mear baseline within 2 hours. Kinase phosphorylation levels of these three MAPKs induced by LPS were found to be dose dependent in a range of 10 pg/ml to 100ng/ml. No phosphorylation was observed in unstimulated cells. Among them, p38 MAPK shoned fastest and highest phosphorylation levels. The results show that LPS can markedly activate ERK, JNK, and p38 MAPK in KC, and p38 MAPK may play a more important role in LPS induced kupffer cell activation than ERR and JNK.