VEGF/PKD-1 signaling mediates arteriogenic gene expression and angiogenic responses in reversible human microvascular endothelial cells with extended lifespan.

Microvascular ECs (MVECs) are an ideal model in angiogenesis research. The aim of this study was to determine vascular endothelial growth factor (VEGF)/protein kinase D1 (PKD-1) signaling in expression of arteriogenic genes in human MVECs. To achieve this aim, we transduced specific SV40 large T antigen and telomerase into primary human dermal MVECs (HMVEC-D) to establish reversible HMVECs with extended lifespan (HMVECi-D). HMVECi-D was then exposed to VEGF/VEGF-inducer GS4012 or transduced with constitutively active protein kinase PKD-1 (PKD-CA). Quantitative RT-PCR was performed to detect arteriogenic gene expression. Furthermore, the angiogenic capacity in response to VEGF pathway was evaluated by Matrigel tube-formation and proliferation assays. We observed that VEGF/PKD-1 signaling axis significantly stimulated the expression of arteriogenic genes and promoted EC proliferation, along with downregulation of CD36 expression. Intriguingly, overexpression of PKD-CA also resulted in formation of tip cell morphology, accompanied by increased mRNA of delta-like ligand 4 (DLL4). In conclusion, we have successfully established and characterized HMVECi-D, and showed that VEGF/PKD-1 signaling axis increases angiogenic and arteriogenic gene expression. These studies suggest that the axis may regulate arteriolar differentiation through changing MVEC gene expression.