Functional Requirement of the Hypoxia-responsive Element in the Activation of the Inducible Nitric Oxide Synthase Promoter by the Iron Chelator Desferrioxamine

作者：Giovanni Melillo, Lynn S. Taylor, Alan Brooks, Tiziana Musso, George W. Cox, Luigi Varesio · 发表于：Journal of Biological Chemistry · 年份：1997 · DOI：10.1074/jbc.272.18.12236 · 被引用次数：202 · 研究领域：Cancer, Hypoxia, and Metabolism、Nitric Oxide and Endothelin Effects、Adipose Tissue and Metabolism

We have previously reported that a 19-base pair element of the 5'-flanking region of the inducible nitric oxide synthase (iNOS) gene containing a sequence homology to a hypoxia-responsive enhancer (iNOS-HRE) mediates picolinic acid (PA)- or hypoxia-induced activation of the iNOS promoter in interferon-gamma (IFN-gamma)-treated murine macrophages. The iron chelator desferrioxamine (DFX) induces the activity of the human erythropoietin enhancer in Hep3B cells. We have investigated the influence of DFX on the activation of the iNOS promoter and iNOS gene expression in ANA-1 macrophages. We have found that DFX induced DNA-binding activity to the hypoxia-inducible factor 1 (HIF-1) consensus sequence of the iNOS promoter and activated the iNOS-HRE in murine macrophages. These activities of DFX were associated with a synergistic induction of iNOS mRNA expression and iNOS transcription in IFN-gamma-treated ANA-1 macrophages. Functional analysis of the 5'-flanking region of the iNOS gene demonstrated that IFN-gamma plus DFX activated the full-length iNOS promoter and that the iNOS-HRE was required for DFX-induced iNOS transcriptional activity. We also investigated the role of iron metabolism in the DFX- or PA-dependent induction of HIF-1 activity and iNOS expression. We demonstrate that addition of iron sulfate completely abolished DFX or PA induction of HIF-1 binding and iNOS-HRE activation and abrogated IFN-gamma plus either DFX- or PA-induced iNOS expression. These data establish t...