Salvianolic acid B inhibits hepatic stellate cell activation and liver fibrosis by targeting PDGFRβ

Liver fibrosis is a reversible pathological process and a wound healing response to liver injury. As an early stage of various liver diseases, liver fibrosis can develop into cirrhosis, liver failure, and even liver cancer if not controlled in time. Salvia miltiorrhiza is a medicinal plant with hepatoprotective effects. Salvianolic acid B (Sal B) is the representative component of S. miltiorrhiza. Many studies have reported the anti-liver fibrosis effects and mechanisms of Sal B. However, the direct anti-fibrotic targets of Sal B have not yet been reported. Platelet-derived growth factor receptor β (PDGFRβ) is one of the most classical targets in liver fibrosis, which is closely related to hepatic stellate cells (HSCs) activated. Previously, we established and applied a PDGFRβ affinity chromatography model, and found that Sal B binds well to PDGFRβ. Therefore, this study aimed to investigate the direct targets of Sal B against liver fibrosis. We confirmed the binding ability of Sal B to PDGFRβ by molecular docking and a surface plasmon resonance biosensor. Our findings indicated that Sal B targeted PDGFRβ to inhibit the activation, migration and proliferation of HSCs and suppressed the PDGF-BB-induced PDGFRβ signaling pathway. Annexin V-FITC/PI assay showed that Sal B reversed the PDGF-BB-induced decrease in HSC apoptosis rate. In the mouse liver fibrosis model, Sal B inhibited the PDGFRβ signaling pathway, HSC activation and reduced inflammatory response, ultimately improved CCl4-induced liver fibrosis. In summary, the direct anti-fibrotic targets of Sal B may be PDGFRβ, and this study clarified the anti-liver fibrosis effects and mechanism of Sal B.