Cyanidin-3-O-β-glucoside polarizes LPS-induced M1 into M2 Macrophage in J774 cells via PPARγ-mediated NF-κB and STAT6 signaling pathway

Macrophage polarization exerts critical effect on inflammatory response. Cyanidin-3-O-beta-glucoside (Cy-3-g), a typical anthocyanin pigment has been reported to have anti-inflammatory property. However, whether Cy-3-g exerts anti-inflammatory effects by modulating macrophage polarization remains unclear. Lipopolysaccharide (LPS) was used to establish the M1 model of J774 cells, in which the effects of Cy-3-g on M1-M2 conversion were explored. Cy-3-g (1, 10, 100 mu M) not only reduced LPS-induced increased expression of proinflammatory factors and but also elevated the levels of anti-inflammatory factors. Moreover, Cy-3-g intervention shifted LPS-polarized M1 into M2, leading to the significant reduction of synthesis of nitric oxide synthase and major histocompatibility complex II (M1 markers), and increase of arginine I and CD206 expression (M2 markers). Further experiments found that Cy-3-g dose-dependently increased peroxisome proliferator-activated receptor-gamma (PPAR gamma) expression. Finally, we determined that Cy-3-g regulated M1-M2 polarization via PPAR gamma-mediated nuclear factor kappa B and signal transducers and activators of transcription 6 signaling pathway.