Regulation of SIRT1-TLR2/TLR4 pathway in cell communication from macrophages to hepatic stellate cells contribute to alleviates hepatic fibrosis by Luteoloside.

Regulating macrophage-hepatic stellate cells (HSCs) crosstalk through SIRT1-TLR2/TLR4 has contributed to the essence of new pharmacologic strategies to improve hepatic fibrosis. We investigated how Luteoloside (LUT), one of the flavonoid monomers isolated from Eclipta prostrata (L.) L., modulates macrophage-HSCs crosstalk during hepatic fibrosis. HSC-T6 or rat peritoneal macrophages were activated by TGF-β or LPS/ATP, and then treated with LUT or Sirtinol (SIRT1 inhibitor) for 6 h. Further, HSCs were cultured with the conditioned medium from the LPS/ATP activated peritoneal macrophages. In HSC-T6 or peritoneal macrophages, LUT could decrease the expressions of α-SMA, Collagen-I, the ratio of TIMP-1/MMP-13. LUT also significantly increased the expressions of SIRT1 and ERRα. And LUT significantly suppressed the releases of pro-inflammatory cytokines, including NLRP3, ASC, caspase-1, IL-1β, and regulated signaling TLR2/TLR4-MyD88 activation. The expressions of TLR2, TLR4, NLRP3, caspase-1, IL-1β, α-SMA were increased and the expression of ERRα was decreased by Sirtinol, indicated that LUT might mediate SIRT1 to regulate TLR4 expression and further alleviate inflammation and fibrosis. LUT could regulate SIRT1-mediated TLR4 and ECM in HSCs was reduced, when HSCs were cultured with conditioned medium. Hence, LUT could decrease the expressions of fibrosis markers, reduce the releases of inflammatory cytokines in activated HSCs or macrophages. In conclusion, LUT might be a promising candidate that regulating SIRT1-TLR2/TLR4 signaling in macrophages interacting with HSCs during hepatic fibrosis.