Figure 1

TGFβ induces CRP2 expression through Smad2/3 and ATF2. (A) TβRI kinase activity contributes to CRP2 induction. VSMCs were pretreated with vehicle or TβRI kinase inhibitor SB431542 (10 μM) for 30 min before stimulation with TGFβ (10 ng/ml) for 24 h. Total proteins were then harvested for Western blot analysis to detect CRP2 expression. SB431542 significantly decreased TGFβ-induced CRP2 expression. Values are mean ± S.E. of at least three experiments. *P < 0.05 vs. control (− TGFβ); ^#P < 0.05 vs. TGFβ-stimulated vehicle group. (B) TβRI kinase activity is required for activation of Smad2/3 but not ATF2. VSMCs were pretreated with vehicle, SB431542, PI3K inhibitor Wortmannin (1 μM), or LY294002 (10 μM) for 30 min prior to stimulation with or without TGFβ for 15 min. Activation of Smad2/3 and ATF2 was then determined with Western blot analysis. (C-D) VSMCs were transfected with 20 nM control siRNA, Smad2/3 siRNA (C) or ATF2 siRNA (D) using Lipofectamine RNAiMAX transfection reagent and then stimulated with or without TGFβ for 24 h. Western blot analysis was performed to detect CRP2, Smad2/3, or ATF2 levels. The membranes were subsequently probed with actin for loading control. Values are mean ± S.E. of at least three experiments. ^#P < 0.05 vs. TGFβ-stimulated siControl group.