Figure 11.

Both TGF-β and PDGF signals stimulate PAI-1 transcriptional activity through pSmad3L in HSCs. HSCs were transiently co-transfected of PF1-Luc with Smad3WT, Smad3EPSM, Smad3(3S-A), or empty control vector (pcDNA3). After changing the medium, cells were incubated for another 30 hours. Under serum-free conditions, the cells were incubated for 12 hours with TGF-β₁, PDGF, or a combination of both. Luciferase activity was determined and normalized to transfection efficiency. Values of samples from cells transfected with PF1-Luc alone and those left untreated were set arbitrarily at 1. Results shown are the mean ± SD (n = 4) from a representative experiment. *, P < 0.05; **, P < 0.01, by one-way analysis of variance.