Effects of NgBR knockdown on VEGF-induced endothelial cell migration and morphogenesis. (A) NgBR knockdown abolished VEGF-stimulated migration of HUVECs. Cell migration was examined in modified Boyden chambers in response to VEGF (100 ng/mL; n = 3). (B-C) NgBR is necessary for VEGF-induced tube formation. After treatment with either NS or NgBR siRNA, HUVECs were suspended in type I collagen gels and treated with vehicle or 100 ng/mL VEGF. After 24 hours of incubation, cells were photographed (B), and total network length was quantified (C). Representative images (B) are shown for 2 independent experiments (n = 3 in C). Scale bar = 100 μm; *P < .05; siRNA: 10nM.