Figure 3. BMP9 Signals through ALK1 and Regulates Endothelial Gene Expression.
(A and B) Western blot analysis of parental HUVECs (A) or control or ALK1 siRNA-transfected HUVECs (B) following stimulation with 10 ng/ml BMP9 for up to 2 hr. (C–E) qPCR analysis of genes involved in SMAD signaling (C), Notch signaling (D), or tip cell specification (E) induced by ALK1 (BMP9) or Notch (sDll4) signaling in HUVECs, alone or in combination after 24 hr stimulation. Graphs represent the average of three to five experiments. All values are mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.005; Student's t test.