Curculigoside A induces angiogenesis through VCAM-1/Egr-3/CREB/VEGF signaling pathway

Curculigoside A may be a powerful way of protecting the brain against a wide variety of injury. In the present study, we sought to elucidate whether Curculigoside A contributes to induce angiogenesis and its mechanisms. To this end, we examined the role of Curculigoside A on proliferation, invasion, and tube formation in the human brain microvascular endothelial cell line (HBMEC) in vitro. For studying mechanism, the cAMP response element-binding protein (CREB) inhibitor 2-naphthol-AS-E-phosphate (KG-501), early growth response 3 (Egr-3) siRNA, vascular endothelial growth factor (VEGF) antagonist sFlt-1 and VEGF receptor 2 (VEGFR2) blocker SU-1498 were used. Human brain microvascular endothelial cell line (HMBEC) proliferation was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Scratch adhesion test was used to assess the ability of invasion. A matrigel tube formation assay was performed to test capillary tube formation ability. Vascular cell adhesion molecule 1 (VCAM-1)/Egr-3/CREB/VEGF pathway activation in HMBEC was tested by Western blot analysis. Our data suggested that Curculigoside A induced angiogenesis in vitro by enhancing the proliferation, invasion and tube formation. VEGF expression was increased by Curculigoside A and counteracted by the soluble VEGF receptor 1 (sFlt-1, VEGF antagonist) and KG-501 in HMBEC. Tube formation was enhanced by Curculigoside A and counteracted by VEGF receptor blocker-SU1498, KG-501 and Egr-3 siRNA. It may be suggested that Curculigoside A induces angiogenesis in vitro via a programed VCAM-1/Egr-3/CREB/VEGF signaling axis.