The effect of NF-κB signaling pathway regulation on PD-L1 expression of Enterococcus faecalis LTA-stimulated macrophages

Objective To investigate the effect of Enterococcus faecalis (E. faecalis) lipoteichoic acid (LTA) on the expression of the macrophage immune checkpoint-programmed cell death protein ligand 1 (PD-L1) and explore the possible regulatory mechanisms. Methods In vitro model was established by stimulating mouse monocyte macrophage cell line (RAW264.7) with different concentrations of E. faecalis LTA. PD-L1 expression and nuclear factor kappa-B (NF-κB) p65 phosphorylation level were detected using flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot and cellular immunofluorescence. Macrophages were pretreated with the NF-κB signaling pathway inhibitor BAY 11-7082, then the expression of PD-L1 and p65 phosphorylation level were detected by the above methods. Results LTA induced PD-L1 expression in RAW264.7 cells, and p65 phosphorylation level increased (P