Ginsenoside-Rg₁ induces angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a

Therapeutic angiogenesis has been implicated in ischemic diseases and wound healing. Ginsenoside-Rg₁ (Rg₁), one of the most abundant active components of ginseng, has been demonstrated as an angiogenesis-stimulating compound in different models. There is increasing evidence implicating microRNAs (miRNAs), a group of non-coding RNAs, as important regulators of angiogenesis, but the role of microRNAs in Rg₁-induced angiogenesis has not been fully explored. In this report, we found that stimulating endothelial cells with Rg₁ could reduce miR-23a expression. In silico experiments predicted hepatocyte growth factor receptor (MET), a well-established mediator of angiogenesis, as the target of miR-23a. Transfection of the miR-23a precursor or inhibitor oligonucleotides validated the inverse relationship of miR-23a and MET expression. Luciferase reporter assays further confirmed the interaction between miR-23a and the MET mRNA 3'-UTR. Intriguingly, ginsenoside-Rg₁ was found to increase MET protein expression in a time-dependent manner. We further demonstrated that ginsenoside-Rg₁-induced angiogenic activities were indeed mediated through the down-regulation of miR-23a and subsequent up-regulation of MET protein expression, as confirmed by gain- and loss-of-function angiogenic experiments. In summary, our results demonstrated that ginsenoside-Rg₁ could induce angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a. This study has broadened our understanding of the non-genomic effects of ginsenoside-Rg_1, and provided molecular evidence that warrant further development of natural compound as novel angiogenesis-promoting therapy.