TGF-β1-induced ECM protein expression in NHLF is down-regulated by BMP-4. NHLF were stimulated with 5 ng/ml TGF-β1 or 100 ng/ml BMP-4 or BMP-7 alone or with TGF-β1 in the presence of BMP-4 or BMP-7 for 24 h (A and B) or 48 h (C and D). Cells were harvested, RNA was extracted, reverse transcribed, and a real-time quantitative PCR for tenascin C (A) and fibronectin (C) was performed. Results are expressed as the ratio of each transcript relative to the geometric mean of mRNA expression of the housekeeping genes UBC, SDHA, and RPL13a. Tenascin C and fibronectin protein were quantified in the cell supernatants by specific ELISAs (B and D, respectively). Data are mean ± SD of five independent experiments. *, p < 0.05, as compared to unstimulated cells and †, p < 0.05, as compared to TGF-β1-stimulated cells.