Intracellular Staphylococcus Aureus Inhibits Autophagy Of Bovine Mammary Epithelial Cells Through Activating P38 Alpha

Staphylococcus aureus is a common pathogen of bovine mastitis which can induce autophagy and inhibit autophagy flux, resulting in intracellular survival and persistent infection. The aim of the current study was to investigate the role of p38 alpha in the autophagy induced by intracellular S. aureus in bovine mammary epithelial cells. An intracellular infection model of MAC-T cells was constructed, and activation of p38 alpha was examined after S. aureus invasion. Through activating/inhibiting p38 alpha by anisomycin/SB203580, the autophagosomes, LC3 and p62 level were analyzed by immunofluorescence and western blot. To further study the detailed mechanism of p38 alpha, phosphorylation of ULK1ser757 was also detected. The results showed that intracellular S. aureus activated p38 alpha, and the activation developed in a time-dependent manner. Inhibition of p38 alpha promoted intracellular S. aureus-induced autophagy flow, up-regulated the ratio of LC3 II/I, reduced the level of p62 and inhibited the phosphorylation of ULK1ser757, whereas the above results were reversed after activation of p38 alpha. The current study indicated that intracellular S. aureus can inhibit autophagy flow by activating p38 alpha in bovine mammary epithelial cells.