Effects of Rnd3 on angiogenesis in mice with hindlimb ischemia through regulation of VEGFA-VEGFR2 signaling pathway

AIM To investigate the impact of Rho family GTPase 3 (Rnd3) on angiogenesis in hindlimb ischemia (HLI) and its underlying mechanisms.

METHODS Mice were randomly allocated to a sham-operated cohort (Sham group) and a hind limb ischemia cohort (HLI group). A hindlimb ischemia model was established utilizing Rnd3 endothelial-specific transgenic mice (Rnd3^ECTG) and their wild-type (WT) littermates. Human umbilical vein endothelial cells (HUVECs) were transfected with adenoviruses harboring Rnd3 (Ad-Rnd3) and its control vectors (Ad-Vector). Blood flow in the hindlimbs was quantified using PeriCam PSI, the level of angiogenesis was determined by immunofluorescence staining, the proliferative capacity of HUVECs was evaluated using EdU incorporation assay, the vascular formation capability of HUVECs was detected using tube formation assays, and protein expressions of important targets and receptors of the Rnd3 and VEGFA pathway were determined in gastrocnemius muscle tissues and HUVECs using Western blot.

RESULTS Compared with those in WT sham surgery group, the expression levels of Rnd3 and VEGFA in the gastrocnemius muscle of hindlimb ischemia model mice were significantly elevated (P<0.01). Endothelial-specific over-expression of Rnd3 markedly accelerated blood flow recovery in ischemic hindlimbs, with a concomitant significant increase in capillary density (P<0.01). Additionally, Rnd3 over-expression fostered endothelial cell proliferation and augmented their tube formation capacity. Compared with those in the Ad-Control group, Rnd3 over-expression significantly increased the phosphorylation levels of VEGFR2 and ERK1/2 in HUVECs (P<0.01).

CONCLUSION Rnd3 effectively augments VEGFA expression, promotes VEGFR2 phosphorylation in HUVECs and enhances endothelial cell proliferation and angiogenesis, ultimately facilitating angiogenesis and the restoration of blood flow in mice following HLI surgery.