Transcriptional induction of hepcidin expression by IL-6 and BMP-2.

<p>(<b>A</b>) RNase protection assays demonstrating dose-dependent induction of hepcidin mRNA by IL-6 in HepG2 and Huh7 cells. U6sn RNA served as loading control. (<b>B</b>) Quantification of hepcidin mRNA induction; means±SD of three independent experiments; *<i>p</i><0.05, **<i>p</i><0.01 <i>vs.</i> unstimulated cells. (<b>C</b>) IL-6 blunted, but did not abrogate the down-regulation of hepcidin mRNA levels by DMOG. IGFBP1 mRNA served as control for the hypoxic stimulation. (<b>D</b>) IL-6 activated the human <i>hepcidin</i> promoter (HAMP.prom) in HepG2 and Huh7 cells. (<b>E</b>) Activation of the <i>hepcidin</i> promoter by BMP-2 (100 ng/ml) was mediated primarily by the proximal promoter, since fusion of the 5′adjacent CpG island to the proximal promoter (HAMP.prom.CpG) did not significantly alter the response to BMP-2. The activation was more pronounced under serum-reduced conditions (0.4% FCS). D–E, data are means±SD of three independent experiments; *<i>p</i><0.05, **<i>p</i><0.01 <i>vs.</i> unstimulated controls.