Fig. 10: ITGA5-mediated angiogenic stimulation of macrophages is dependent on PI-3K/Akt and FAK signaling.

A, B We used treatment of bone marrow macrophages (BMMs) with pharmacologic inhibitors to examine the role of Phosphoinositide-3 Kinase (PI-3K)/Akt (A) and Focal Adhesion Kinase (FAK) (B) signaling in ITGA5-mediated Vegfa synthesis. ITGA5 blockade markedly reduced Vegfa expression in BMMs (A, B). Treatment with the PI-3K/Akt inhibitor LY294002 (20 µM, A), or with the FAK inhibitor PF-573228 (5 µM, B) markedly attenuated Vegfa synthesis in macrophages with intact ITGA5 signaling (IgG group), but had no significant effects on Vegfa levels upon ITGA5 blockade (A, B). C–I Western blotting experiments (C) were used to examine the role of ITGA5 signaling on PI-3K/Akt and FAK activation in fibronectin-treated BMMs. PI-3K/Akt expression and activation (C, D–F) were markedly attenuated upon ITGA5 blockade. Moreover, ITGA5 blockade modestly but significantly attenuated FAK activation, without significantly affecting total FAK levels (C, G–I). In order to examine whether PI-3K/Akt activation in ITGA5-stimulated macrophages is dependent on FAK, the effects of the FAK inhibitor PF-573228 on PI-3K/Akt expression and activation were examined. Western blotting showed the FAK inhibitor had no significant effects on PI-3K/Akt expression and activation, in the presence or absence of ITGA5 blockade (J–M) (****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05, n = 3 biologically independent experiments/group). Thus, ITGA5-mediated angiogenic activation of macrophages is dependent on independent FAK and PI-3K pathways. Data are shown as mean values +/- SEM. Statistical analysis was performed using one-way ANOVA, followed by Sidak post-hoc test. Source data are provided as a Source Data file. Inh inhibitor.