Fig. 2.

In NRCs, inhibition of BMP signaling prevents the development of PE-induced hypertrophy. Treatment of NRCs with PE (10 μM) increased NPPB and NPPA (A), Id1 mRNA levels (B), and hNPPB promoter activity (C), an effect that was inhibited by pretreatment with LDN (100 nM) or noggin (NOG; 100 ng/ml). D: treatment with PE increased the cellular area of NRCs, an effect that was inhibited by treatment with LDN or NOG. E: quantification of the relative area of NRCs treated with PE, or PE and inhibitor. The no. of cells counted per treatment = 25–30. Depletion of Smad 1 or Smad 4 in NRCs using small interfering RNAs (siRNAs; F) inhibited the ability of PE to increase NRCs size (G and H) and induce NPPB and NPPA gene expression (I). In G, cells were stained with rabbit anti-actinin antibody and fluorescein-conjugated donkey anti-rabbit IgG antiserum, and 25–30 cells were counted per treatment. Values are means ± SE; n = 4 samples per experimental group in A, B, F, and I; n = 6 in C. Bar in D and G indicates 50 μm. **P < 0.01 vs. saline treatment. ††P < 0.01 vs. PE control. ^ΦP < 0.001 vs. corresponding siNC transfected cells. siNC, nontargeting siRNA; siSmad, siRNA against Smad.