FIGURE 3.

Fstl3 ablation attenuates the hypertrophic actions of PE treatment in cultured cardiac myocytes. A and B, results of real-time PCR and Western blot analysis of Fstl3 (A) and activin A (B) gene expression with unrelated or Fstl3 siRNA in the presence or absence of PE (100 μmol/liter) for 24 h. C and D, no effect of Fstl3 deletion on activin A mRNA and protein expression by NRVMs. Activin A protein levels in media were assessed by ELISA. E, effect of Fstl3 knockdown on Smad2 phosphorylation. Relative phosphorylated levels of Smad2 were normalized to control values in NRVMs that were not targeted with siRNA. F, representative fluorescence microscope images of NRVMs transfected with unrelated siRNA or Fstl3 siRNA for 48 h following by stimulation with phenylephrine (PE, 100 μmol/liter) for 24 h. G and H, quantitative analysis of cell surface area (G) and protein synthesis (H) assessed by [³H]leucine incorporation after siRNA transfection with or without PE. *, p < 0.05 versus corresponding control without PE; #, p < 0.05 versus corresponding no-targeting siRNA.