Fig. 3.

Human hepcidin promoter activity is repressed by hypoxia and oxidative stress. HuH7 cells were transfected with luciferase reporter constructs and 24 h later were exposed to hypoxia (1% O₂) or 100 μM H₂O₂ for 24 h in the absence (A) or presence (B–F) of activated THP-1 cells. Luciferase activity was measured after 24 h. Hepcidin promoter activity was repressed by hypoxia and H₂O₂ treatments in HuH7 cocultures transfected with the wild-type (B) and E-box (C)-, signal transducer and activator of transcription 3 (STAT3) (D)-, and CCAAT/enhancer-binding protein (C/EBP)-mutant (E) constructs. No effect of hypoxia and H₂O₂ treatments was observed in HuH7 monocultures transfected with the wild-type promoter (A) or in cocultures transfected with bone morphogenetic protein (BMP)/SMAD mutant promoter (F). Data are means ± SE of 4–6 observations in each group and are expressed as a percentage of the control group for each experiment. Different letters above data bars indicate that these groups are significantly different (P < 0.05).