Fig. 3.

VEGF-C stimulates PI3Kα-dependent integrin α4β1 activation during lymph node lymphangiogenesis. (A) pAkt/Akt immunoblotting in VEGF-C–stimulated LECs. (B) Immunoblots of PI3K isoforms in cultured LECs and vascular endothelial cells. (C) pAkt/Akt immunoblotting in VEGF-C–stimulated LEC ± 500 nM PIK2α or control. (D) Lymph nodes treated with saline, VEGF-C, the PI3Kγ inhibitor (TG100–115), or the PI3Kα inhibitor (PIK2α). (E) Lyve-1⁺ pixels per field in VEGF-C, TG100-115, LY294002, or PIK2α treated lymph nodes from WT or mutant animals lacking PI3Kγ (p110γ^−/−) animals (n = 10, **P < 0.001). (F–H) Saline- or VEGF-C–stimulated LEC adhesion to VCAM-1. (G) Saline- or VEGF-C–stimulated LEC adhesion to VCAM-1 ± 1 µM PI3Kα inhibitor PIK2α. (H) LEC adhesion to VCAM-1 of control and p110α (Hs_PIK3CA_8) siRNA transfected cells ± VEGF-C. (Scale bars, 50 µm.)