Pp2cm基因沉默对小鼠巨噬细胞通过TLR通路抵抗金黄色葡萄球菌感染的影响

OBJECTIVE: To investigate the effect of silencing protein phosphatase 2cm (Pp2cm) gene on the expression of inflammatory factors in macrophages infected with Staphylococcus aureus (S. aureus) and the mechanisms involved. METHODS: The effects of Pp2cm knockdown on inflammatory factors, proliferation, apoptosis, and Toll-like receptor (TLR) signaling were analyzed in RAW 264.7 cells, a murine macrophage cell line, transfected with adenovirus (Ad). The cells were divided into four groups, including Ad-Ctrl group, Ad-Pp2cm group, Ad-Ctrl+S. aureus group and Ad-Pp2cm+S. aureus group. Cell transfection was achieved by separately introducing control adenovirus (Ad-Ctrl) or adenovirus targeting the Pp2cm gene (Ad-Pp2cm) and inflammation or the absence of inflammation was induced by applying or not applying S. aureus. The expression of tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), TLR2, TLR4, Toll-like receptor adaptor protein (Tirap) and myeloid differentiation factor 88 (Myd88) was determined by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). PP2Cm protein expression was determined by Western blot. Cell proliferation was determined by cell counting kit-8 (CCK-8) assay and cell apoptosis was measured by flow cytometry. RESULTS: The expression of Pp2cm gene and PP2Cm protein was downregulated in the Ad-Pp2cm group when compared to the Ad-Ctrl group, with the diference showing statistical significance (P<0.05). When compared to those of the Ad-Ctrl+S. aureus group, macrophages in the Ad-Pp2cm+S. aureus group showed significantly increase in the TNF-α and IL-1β gene levels (P<0.01). Furthermore, the Ad-Pp2cm group demonstrated elevated gene expression levels of TLR2, TLR4, Tirap and Myd88 in macrophages when compared to the Ad-Ctrl group, with the difference showing statistical significance (P<0.05). There were no statistically significant differences in cell apoptosis and proliferation between the Ad-Ctrl and Ad-Pp2cm groups. CONCLUSIONS: Silencing Pp2cm gene promotes the inflammatory response of macrophages to S. aureus infection. Moreover, the TLR pathway plays an important role in the inflammatory activation of macrophages.