(A,B) Adherent quiescent human aortic SMCs expressing tTG shRNA (shtTG), non-silencing shRNA (control) or tTG were treated with 10 nM PDGF-BB for 72 hours. (A) tTG increases fibronectin mRNA levels and enhances PDGF-BB-dependent down-regulation of SM α-actin mRNA. mRNA levels of tTG, fibronectin, SM α-actin, and tubulin were determined by quantitative RT-PCR. (D) tTG increases the levels of fibronectin and promotes PDGF-BB-induced down-regulation of SM α actin. The levels of tTG, fibronectin, SM α-actin, and tubulin were defined by immunoblotting. The amounts of fibronectin and SM α-actin mRNAs (B,C) and proteins (E,F) were quantified by densitometry, averaged, and expressed as -fold increase over those in control cells without PDGF-BB treatment. Shown are the means ± S.D. for three independent experiments.