TanshinoneIIA Alleviates Inflammatory Response and Directs Macrophage Polarization in Lipopolysaccharide-Stimulated RAW264.7 Cells

TanshinoneIIA (TanIIA) has been demonstrated to possess numerous biological effects. However, the specific effect of TanIIA on macrophage polarization has not been reported. In this study, it was revealed that TanIIA might play a pivotal role in macrophage polarization. As our results indicated, cell morphology was changed in RAW264.7 cells which were treated with LPS or LPS/TanIIA (0.1 μM, 1 μM, 10 μM). Subsequently, pro-inflammatory cytokine TNF-α and anti-inflammatory cytokine IL-10 were measured by ELISA kits. Furthermore, TanIIA enhanced the expression of M2 macrophage markers (Arg1 and FIZZ1) and decreased the expression of markers associated with M1 macrophage polarization (iNOS and IL-1β). Increased expression of CD206 was also detected by flow cytometry in TanIIA-treated groups. Mechanistically, it was revealed that TanIIA modulated macrophage polarization by ameliorating mitochondrial function and regulating TLR4-HMGB1/CEBP-β pathway. In addition, increased expression of miR-155 was observed in RAW264.7 cells incubated with LPS and were effectively inhibited by TanIIA. Taken together, it was suggested that TanIIA inhibits inflammatory response and promotes macrophage polarization toward an M2 phenotype, which provides new evidence for the anti-inflammation activity of TanIIA.