Knockdown of SUCNR1 suppresses the angiogenic phenotype of HUVECs. (A) Representative histogram of flow cytometric analysis of DY-547 labeled positive control SiRNA at 24, 48 and 72 h. (B) Representative Western blot of SUCNR1 in non-transfected, control or SUCNR1 SiRNA-transfected HUVECs at 72 h post transfection. (C) Representative image for immunofluorescence staining of SUCNR1 in HUVECs transfected with either control or SUCNR1 SiRNA for 72 h. DAPI was used for counterstaining (scale bar 10 µm, objective 20×). (D) RT-PCR of VEGF gene expression in control or SUCNR1 SiRNA-transfected HUVECs treated with either vehicle or succinate for 4 h. (E) Transwell migration assay of control or SUCNR1 SiRNA-transfected HUVECs in response to vehicle or succinate after 16 h; representative images are shown (scale bar 200 µm, objective 10×). (F) Scratch assay in control or SUCNR1 SiRNA-transfected HUVECs treated with vehicle or succinate for 12 h; representative images are shown (scale bar 500 µm, objective 10×). D, E and F were analyzed by two-way ANOVA followed by Tukey’s post hoc test, * p < 0.05, ** p < 0.01, *** p < 0.0001, data are shown as mean ±SEM (n = 3-5).