Inhibition Effect of Ginkgo biloba Extract(EGb761) on the Phenotypic Switch of Vascular Smooth Muscle Cells through Regulation of APMK/KLF4 Signaling Pathway / 中国药学杂志

ABSTRACT

OBJECTIVE: To explore the effects of Ginkgo biloba extract (EGb761) on platelet derived growth factor (PDGF)-induced phenotypic switch of vascular smooth muscle cells (VSMCs) and its potential mechanisms. METHODS: VSMCs were cultured in vitro, and 20 ng•mL-1 PDGF was used to induce the phenotypic switch of VSMCs. MTT assay and wound healing assay were performed to determine the effects of various concentration (1, 10, 100 μg•mL-1) of EGb761 on cell proliferation and migration, respectively; immunofluorescence and Western blot assay were used to detect the arrangement of myofilament, the expression of phenotypic proteins including α-SMA, calopnin and OPN, as well as the protein expression of AMPK/KLF4 signaling pathway. RESULTS: Compared with the control group, PDGF significantly promoted the proliferation and migration of VSMCs. However, EGb761 treatment inhibited PDGF-induced cell proliferation and migration in a concentration-dependent manner. Compared with the control group, PDGF treatment induced disordered arrangement of myofilament and reduced the fluorescence intensity of F-actin. In addition, PDGF significantly decreased the expression of α-SMA and calponin, whrease increased the expression of OPN in VSMCs, when compared with the control group. VSMCs in PDGF+EGb761 group showed well-aligned myofilament and enhanced the fluorescence intensity of F-actin; the expressions of α-SMA and calponin were increased and OPN was decreased in the PDGF+EGb761 group when compared with the PDGF group. Meanwhile, as compared with the control group, PDGF increased the level of phosphorylated AMPK and the expression levels of KLF4, which was inhibited by the addition of EGb761 in a concentration dependent manner. After inhibition of AMPK/KLF4 signaling pathway with the use of specific AMPK pathway inhibitor compound C, the inhibitory effect of EGb761 on PDGF-mediated phenotypic switch of VSMCs was enhanced; vice versa, the activation of AMPK/KLF4 signaling pathway with AMPK pathway activator AICAR and the inhibitory effect of EGb761 on PDGF-mediated phenotypic switch of VSMCs were reversed. CONCLUSION: EGb761 inhibits PDGF-mediated phenotypic switch of VSMCs by targeting APMK/KLF4 signaling pathway.