Vascular Endothelial Growth Factor (VEGF)-D Stimulates VEGF-A, Stanniocalcin-1, and Neuropilin-2 and Has Potent Angiogenic Effects

Objective-The mature form of human vascular endothelial growth factor-D (hVEGF-D-Delta N Delta C) is an efficient angiogenic factor, but its full mechanism of action has remained unclear. We studied the effects of hVEGF-D-Delta N Delta C in endothelial cells using gene array, signaling, cell culture, and in vivo gene transfer techniques. Methods and Results-Concomitant with the angiogenic and proliferative responses, hVEGF-D-Delta N Delta C enhanced the phosphorylation of VEGF receptor-2, Akt, and endothelial nitric oxide synthase. Gene arrays, quantitative reverse transcription-polymerase chain reaction, and Western blot revealed increases in VEGF-A, stanniocalcin-1 (STC1), and neuropilin (NRP) 2 expression by hVEGF-D-Delta N Delta C stimulation, whereas induction with hVEGF-A(165) altered the expression of STC1 and NRP1, another coreceptor for VEGFs. The effects of hVEGF-D-Delta N Delta C were seen only under high-serum conditions, whereas for hVEGF-A(165), the strongest response was observed under low-serum conditions. The hVEGF-D-Delta N Delta C-induced upregulation of STC1 and NRP2 was also evident in vivo in mouse skeletal muscle treated with hVEGF-D-Delta N Delta C by adenoviral gene delivery. The importance of NRP2 in hVEGF-D-Delta N Delta C signaling was further studied with NRP2 small interfering RNA and NRP antagonist, which were able to block hVEGF-D-Delta N Delta C-induced survival of endothelial cells. Conclusion-In this study, the importance of serum and upregulation of NRP2 and STC1 for VEGF-D-Delta N Delta C effects were demonstrated. Better knowledge of VEGF-D-Delta N Delta C signaling and regulation is valuable for the development of efficient and safe VEGF-D-Delta N Delta C-based therapeutic applications for cardiovascular diseases. (Arterioscler Thromb Vasc Biol. 2011; 31:1617-1624.)