KCNK3 expression is required for BMP-induced switching of HPASMC phenotypes. (A, B) SiRNA-mediated KCNK3 knockdown blocked the anti-proliferative effect of BMPs on HPASMCs. SiRNA-transfected and non-transfected cells were cultured with or without BMPs (100 ng/ml) in growth media for 72 h and then stained with anti-Ki67 IgG. The percentages of Ki67+ cells were measured (n = 6). (C-E) SiRNA-mediated KCNK3 knockdown blocked the BMP-induced expression of differentiation marker genes in HPASMCs. SiRNA-transfected and non-transfected cells were cultured with or without BMPs (30 ng/ml) in growth media for 48 h and then stained with anti-SM-MHC IgG (red). The percentages of SM-MHC+ cells were measured (n = 4). In (E), mRNA levels of KCNK3 and SMC differentiation marker genes (ACTA2, TAGLN) were analyzed using RT-PCR and expressed relative to those in untreated Cont (n = 4). In (A) and (B), nuclei are shown in blue (DAPI). Scale bars = 50 μm. All data are presented as mean ± SEM (*P < 0.05, **P < 0.01, ***P < 0.001).