Wei-Tong-Xin exerts anti-inflammatory effects through TLR4-mediated macrophages M1/M2 polarization and affects GLP-1 secretion

Abstract Objectives The present study was undertaken to explore the effects and mechanisms of Wei-Tong-Xin (WTX) in inhibiting lipopolysaccharide (LPS)-induced inflammatory response of macrophages, in turn, to study the influences on GLP-1 secretion of GLUTag cells. Methods We first evaluated the activation of Raw 264.7 cells and measured the intracellular ROS, CD86 and CD206 levels by flow cytometry. The expressions of proteins were detected by western blot and immunofluorescence. GLP-1 levels were detected by ELISA kits. TLR4 siRNA was used to investigate the role of TLR4 in the regulation of macrophage polarization by WTX. Key findings The results showed that WTX inhibited LPS-induced polarization of macrophages toward the M1 phenotype, but promoted the M2 phenotype. Meanwhile, WTX inhibited the TLR4/MyD88 pathway. The polarization of M1 phenotype promoted GLP-1 secretion by GLUTag cells, which was inhibited by WTX. The results of siRNA showed that WTX exhibited anti-inflammatory effects through targeting TLR4. Conclusions Overall, WTX inhibited polarization of macrophages towards M1 phenotype but promoted the amounts of M2 phenotype, further the macrophages regulated by WTX alleviated GLP-1 content secreted by GLUTag cells. The aforementioned results were produced by WTX-mediated TLR4.