Fig. 5

Activin A regulation of MRTF-A contributes to αSMA induction by TGFβ1 in MC. a ActA (20 ng/ml) and TGFβ1 show an additive effect on αSMA promoter transcriptional activation at 24 h (n = 6). Activin inhibition with b follistatin (n = 7) and c an actA neutralizing antibody decrease TGFβ1-induced αSMA promoter transcriptional activity (n = 14–23). d actB neutralization does not decrease TGFβ1-induced αSMA promoter transcriptional activity (n = 6–9). e actA increases MRTF-A nuclear localization at 18 h (n = 5). TGFβ1-induced nuclear MRTF-A translocation is attenuated with f follistatin (n = 9) and g actA neutralization (n = 5). h ActA-induced αSMA promoter transcriptional activity is inhibited by MRTF-A siRNA (n = 9) and i the Smad3 inhibitor SIS3 (n = 3). *, **, ***, ****P < 0.05, 0.01, 0.001, 0.0001; one-way ANOVA with Tukey’s multiple comparisons post hoc test