Whether autophagy affects methicillin-resistant Staphylococcus aureus (MRSA)-induced
sepsis and the associated mechanisms are largely unknown. This study investigated the role of autophagy in MRSA-induced
sepsis. The levels of
microtubule-associated protein light chain 3 (LC3)-II/I,
Beclin-1 and p62 after USA300
infection were examined by Western blotting and immunohistochemical staining. Bacterial burden analysis,
hematoxylin-
eosin staining, and Kaplan-Meier analysis were performed to evaluate the effect of autophagy on MRSA-induced
sepsis. IFN-γ and
IL-17 were analyzed by ELISA, and CD4+ T cell differentiation was assessed by flow cytometry. Our results showed that LC3-II/I and
Beclin-1 were increased, while p62 was decreased after
infection. Survival rates were decreased in the LC3B-/- and
Beclin-1+/- groups, accompanied by worsened organ
injuries and increased IFN-γ and
IL-17 levels, whereas
rapamycin alleviated organ damage, decreased IFN-γ and
IL-17 levels, and improved the survival rate. However, there was no significant difference in bacterial burden. Flow cytometric analysis showed that
rapamycin treatment decreased the frequencies of Th1 and Th17 cells, whereas these cells were upregulated in the LC3B-/- and
Beclin-1+/- groups. Therefore, autophagy plays a protective role in MRSA-induced
sepsis, which may be partly associated with the alleviation of organ
injuries via the downregulation of Th1 and Th17 responses. These results provide a nonantibiotic treatment strategy for
sepsis.