Fig. 9. The role of SRF and myocardin in the SPC-induced differentiation of hATSCs to SMCs. Serum-starved hATSCs were treated with vehicles, 2 µM D-erythro-SPC, or 2 ng/ml TGF-ß3 for 24 hours, and SRF and myocardin mRNA levels were determined by semi-quantitative RT-PCR (A) or real time RT-PCR (B). Representative data from three independent experiments are shown in A. The data in B are shown as mean ± s.e.m. (n=3). (C) hATSCs were transfected with control siRNA or siRNAs specific for SRF or myocardin, respectively. The levels of SRF and myocardin mRNAs were determined by semi-quantitative RT-PCR. Representative data from three independent experiments are shown. (D) The siRNA-transfected hATSCs were treated with vehicle, 2 µM D-erythro-SPC, or 2 ng/ml TGF-ß3 for 4 days, and the expression levels of -SMA and actin were determined by western blot analysis. (E) The quantity of -SMA and actin were determined in triplicate, and the expression levels of -SMA were normalized to total actin levels in the samples. The data are presented as a percentage of mock-treated control. ^*Significantly different from control value (P<0.05).