[Paeonol inhibits macrophage M1 polarization by down-regulating miR-155/JAK1-STAT1 pathway]

The aim of this paper was to investigate the effect and mechanism of paeonol on peritoneal macrophage M1 polarization in mice, explore whether the intervention action is related to the down-regulation of miR-155 and the inhibition of downstream JAK1-STAT1 pathway, and provide a new idea for the molecular mechanism of paeonol against atherosclerosis(AS). Lipopolysaccharide(LPS) and interferon-γ(IFN-γ) were used to stimulate macrophages for 24 hours to establish the M1 polarization model, and paeonol was given 24 hours before co-stimulation to provide a pre-protective effect on cells. CCK-8 assay was used to detect the cells damage induced by LPS and IFN-γ co-stimulation; flow cytometry was used to detect the expression of M1 surface markers F4/80 and CD86. ELISA was used to detect the secretion of interleukin 6(IL-6) and tumor necrosis factor-α(TNF-α) in supernatant. RT-qPCR was used to detect the expression of miR-155, and Western blot was used to detect the protein expression at JAK1-STAT1-SOCS1 pathway. The results showed that LPS and IFN-γ had no obvious damage to the cells at the optimal concentration, but they induced macrophages polarized to M1, resulted in high expression of M1 type marker factors F4/80 and CD86 on the cell surface, and increased secretion of IL-6 and TNF-α on the cell surface(P<0.05 or P<0.01). Paeonol significantly reduced the LPS and IFN-γ-induced high expression of F4/80 and CD86, the secretion of inflammatory factors IL-6 and TNF-α(P<0.05 or P<0.01), decreased the expression level of miR-155, significantly down-regulated the protein phosphorylation level of JAK1-STAT1 and up-regulated the protein expression of SOCS1(P<0.01) in RAW264.7 cells. The results showed that paeonol could inhibit M1 polarization of macrophages by down-regulating cell surface marker factors and inflammatory factors secreted by cells, which may be related to the down-regulation of miR-155 expression and the inhibition JAK1-STAT1 pathway activation.

Keywords: JAK1-STAT1 pathway; M1 type polarization; miR-155; paeonol.