Fig. 5

Effect of α2AP on the VEGF signaling through ATGL/SHP2 axis in endothelial cells (ECs). a ECs were pretreated with 4 nM α2AP for 30 minutes and then stimulated with 100 pg/mL VEGF for the indicated periods. Phosphorylation of each protein was examined by western blot analysis. b ECs were stimulated with 4 nM α2AP for the indicated periods. Phosphorylation of SHP2 was examined by western blot analysis. c ECs were cultured for 30 minutes in the absence or presence of 4 nM α2AP or 100 μM NSC87877, and then stimulated with 100 pg/mL VEGF for 15 minutes. Phosphorylation of each protein was examined by western blot analysis. d ECs were transfected with control or ATGL siRNA. At 24 hours after transfection, the cells were stimulated with 4 nM α2AP for 5 minutes. The expression of each protein was examined by western blot analysis. e ECs were pretreated with 10 μM BEL for 30 minutes and then stimulated with 4 nM α2AP for 5 minutes. Phosphorylation of SHP2 was examined by western blot analysis. f ECs were pretreated with 4 nM α2AP or 10 μM BEL for 30 minutes and then stimulated with 100 pg/mL VEGF for 15 minutes. Phosphorylation of each protein was examined by western blot analysis. g The proposed mechanism of α2AP-attenuated vascular endothelial functions. VEGF induced Akt, ERK1/2, and p38 activation and led to pro-angiogenic effects, such as tube formation, cell proliferation, and endothelial junction-associated protein production in ECs. On the other hand, α2AP activated SHP2 through ATGL, and then α2AP-induced SHP2 activation inhibited VEGF signaling in ECs. α2AP inhibited VEGF signaling through the ATGL/SHP2 axis, and may cause impairment of vascular functions