The effect of selenium on the autophagy of macrophage infected by Staphylococcus aureus

Abstract

Selenium can alleviate the inflammatory reaction infected by Staphylococcus aureus (S. aureus). However, the role of selenium on the autophagy in RAW264.7 macrophages infected by S. aureus has not been reported. The goal of this study was to clarify the effect of selenium on the autophagy and related inflammatory pathways (MAPK and NF-κB) in RAW264.7 macrophages infected by S. aureus. RAW264.7 macrophages were co-treated with Na₂SeO₃ and S. aureus. The expression of related inflammatory pathways (MAPK and NF-κB) and autophagy-related proteins were detected by Western blotting. The microtubule-binding protein light chain 3 (LC3) puncta were measured with immunofluorescence staining. The ultrastructure of RAW264.7 macrophages infected by S. aureus was detected by transmission electron microscope (TEM). And plate counting method was used to detect the proliferation of S. aureus in RAW264.7 macrophages. The results showed that the expression levels of LC3 II increased and the expression levels of p62 decreased after adding selenium, compared with S. aureus infection group. Compared with S. aureus infection group, the intracellular LC3 puncta and autophagic vesicles, autophagosomes, and autolysosomes increased with selenium supplementation. The number of S. aureus proliferation decreased with addition of selenium, compared with S. aureus infection group. Selenium could significantly inhibit the phosphorylation of MAPK and NF-κB signaling pathway key proteins, compared with S. aureus infection group. In summary, selenium could promote the autophagy in macrophages infected by S. aureus, alleviate the blockade of autophagic flow, depress the transcription of MAPK and NF-κB signaling pathways, and inhibit the proliferation of S. aureus in RAW264.7 macrophages.

Keywords: Autophagy; MAPK; Macrophage; NF-κB; Selenium; Staphylococcus aureus.