Figure 6. NOX4 regulates vascular endothelial growth factor–induced endothelial cell proliferation through activation of STAT3. Cell proliferation was measured in human retinal microvascular endothelial cells (hRMVECs) transfected with control siRNA (ConsiRNA) or siRNA to either NOX4 (NOX4siRNA; A) or STAT3 (STAT3siRNA; B) and treated with PBS or vascular endothelial growth factor (VEGF; 20 ng/ml; **p<0.01 and ***p<0.001 versus PBS of ConsiRNA; ^†††p<0.001 versus standard deviation [SD], VEGF of ConsiRNA; one-way ANOVA with post-hoc Newman–Keuls multiple comparison testing).