Abstract
This study aimed to determine the role of bacterial lipoprotein (BLP) in autophagy and apoptosis. Western blot was used to examine autophagy biomarkers in mouse bone marrow-derived macrophages (BMDMs) after infection with Salmonella typhimurium (S. typhimurium) and Staphylococcus aureus (S. aureus) and BLP stimulation. In BMDMs, enhanced protein expression of LC3-II was observed after S. typhimurium or S. aureus infection (P < 0.05) and BLP stimulation (P < 0.05). Autophagy inhibition by chloroquine resulted in increased levels of LC3-Ⅱ and p62 protein (P < 0.05). Persistently upregulated expressions of Atg3 and Atg7 were observed following BLP stimulation (P < 0.05), and knockdown of Atg3 or Atg7 significantly attenuated BLP-enhanced protein expression of LC3-Ⅱ in BMDMs. Furthermore, we found that the autophagy inhibitor 3-methyladenine prevented BLP- and infection-induced macrophage apoptosis. BLP is not only required for autophagy and apoptosis activation in macrophages but also for regulating the balance between autophagy and apoptosis.