OBJECTIVETo investigate the role of p38MAPK signaling pathway in autophagy of intestinal epithelial cells induced by spvB of S.typhimurium.

METHODSHenle-407 cells in exponential growth were infected with wild-type S.typhimurium strain STM-211 (with spvB gene), spvB mutated strain STM-delata;spvB, or with delata;spvB-complemented strain STM-c-spvB after treatment of the cells with the p38MAPK inhibitor SB203580. At different time points of co-culture, the cells were collected and the intracellular bacteria were counted. Western blotting was performed to detect the expressions of phosphorylated p38 and autophagy-related proteins LC3 and p62; immunofluorescence staining was used to observe the expression and distribution of LC3.

RESULTSAt 1, 2 and 4 h after the infection, the phosphorylation levels of p38 in STM-211 group and STM-c-spvB group were significantly lower than that in STM-delata;spvB group (P<0.05). At 2 and 4 h of co-culture, the intracellular bacterial counts were significantly greater in STM-211 and STM-c-spvB infection groups than in STM-delata;spvB group (P<0.05). Pretreatment with p38 inhibitor SB203580 did no significantly affect the expression levels of LC3 II or P62 in STM-211 and STM-c-spvB groups, but caused significant reduction in their expressions in STM-delata;spvB group at 1 h (P<0.05), and such changes were more obvious at 3 h (P<0.05).

CONCLUSIONThe inhibitory effect of spvB gene on autophagy in intestinal epithelial cells is related with the negative regulation of p38MAPK signaling pathway.