Figure 5. NOX4 regulates vascular endothelial growth factor–induced STAT3 activation through interacting with phosphorylated vascular endothelial growth factor receptor 2 in human retinal microvascular endothelial cells. Western blots of phosphorylated vascular endothelial growth factor receptor 2 (p-VEGFR2) and total VEGFR2 (A) and phosphorylated STAT3 (p-STAT3) and total STAT3 (B) in human retinal microvascular endothelial cells (hRMVECs) transfected with ConsiRNA or NOX4siRNA and treated with PBS or VEGF (20 ng/ml); (C) coimmunoprecipitation of NOX4 with VEGFR2 and western blots of p-VEGFR2 and total VEGFR2 in hRMVECs treated with VEGF with or without pretreatment of SU5416 (Con, control; SU, SU5416; V, VEGF). D: Western blots of p-STAT3 and total STAT3 were performed in hRMVECs treated with VEGF and pretreated with AG490, apocynin or respective controls (C, control; AG, AG490; APO, apocynin; **p<0.01 versus control and ††p<0.01 versus VEGF, one-way ANOVA with post-hoc Newman–Keuls multiple comparison testing; n=3 and results are means±SD).