Suppression of hepcidin transcript levels is not mediated by HIF-1α or HIF-2α.

<p>(<b>A</b>) SiRNA-mediated knock-down of HIF-1α (1α) or HIF-2α (2α) did not attenuate the down-regulation of hepcidin mRNA levels in HepG2 cells after 16 h of stimulation; luciferase (luc) siRNA served as negative control. (<b>B</b>) Immunoblots demonstrating the efficiency of HIF-1α and HIF-2α knock-down in HepG2 and Huh7 cells. (<b>C</b>) mRNA expression of the established HIF target genes ANGPTL4 (HIF-1α target) and IGFBP1 (HIF-2α target in hepatoma cells) after HIF-α knock-down in HepG2 cells. (<b>D</b>) Two independent HIF-1α siRNAs (1α, 1α*) reversed the hypoxic down-regulation of the negatively regulated HIF-1 target NUP98. (<b>E</b>) In Huh7 cells hepcidin mRNA down-regulation by DMOG was not affected by HIF-α knock-down, whereas the decrease of NUP98 mRNA was reversed by HIF-1α knock-down. Results shown are representative of at least three independent experiments.