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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2009-10-30
pubmed:abstractText
Hepcidin is an antimicrobial peptide involved in regulating iron homeostasis. It is induced by iron overload and decreased by hypoxia and anemia. Hepcidin regulates iron metabolism by inhibiting iron absorption by the duodenum and by inhibiting macrophage iron recycling. Hepcidin is induced in hepatocytes during the acute-phase response by IL-6. Previously, we have shown that hepcidin is not induced in macrophages by IL-6 but is induced by the synergistic interaction of IFN-gamma and Mycobacterium tuberculosis infection. In the present study, we examined the pathways involved in inducing macrophage hepcidin expression. We show that TLRs TLR2 and TLR4 and the transcription factor STAT1 are required for induction of hepcidin mRNA. Hepcidin promoter activity is also synergistically induced in RAW264.7 macrophages by IFN-gamma and M. tuberculosis. NF-kappaB and C/CEBP binding sites are required for promoter activity. Binding of NF-kappaB (p50/p65) to the NF-kappaB site and STAT1 and C/EBPbeta to the C/CEBP site was confirmed by EMSA. Knockdown of STAT1 and C/EBPbeta expression in RAW264.7 cells with siRNA plasmids inhibited hepcidin promoter activity induced by IFN-gamma and M. tuberculosis. Together, these studies demonstrate that macrophage hepcidin expression is induced by the activation of STAT1 and NF-kappaB and the induction of C/EBPbeta expression.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1938-3673
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
86
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1247-58
pubmed:meshHeading
pubmed-meshheading:19652026-Animals, pubmed-meshheading:19652026-Antimicrobial Cationic Peptides, pubmed-meshheading:19652026-Bone Marrow Cells, pubmed-meshheading:19652026-CCAAT-Enhancer-Binding Protein-beta, pubmed-meshheading:19652026-DNA Primers, pubmed-meshheading:19652026-Gene Expression Regulation, pubmed-meshheading:19652026-Interferon-gamma, pubmed-meshheading:19652026-Macrophages, pubmed-meshheading:19652026-Mice, pubmed-meshheading:19652026-Mice, Inbred C57BL, pubmed-meshheading:19652026-Microscopy, Confocal, pubmed-meshheading:19652026-Mycobacterium Infections, pubmed-meshheading:19652026-NF-kappa B, pubmed-meshheading:19652026-Promoter Regions, Genetic, pubmed-meshheading:19652026-RNA, Messenger, pubmed-meshheading:19652026-Restriction Mapping, pubmed-meshheading:19652026-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:19652026-STAT1 Transcription Factor, pubmed-meshheading:19652026-Transcription, Genetic
pubmed:year
2009
pubmed:articleTitle
Role of STAT1, NF-kappaB, and C/EBPbeta in the macrophage transcriptional regulation of hepcidin by mycobacterial infection and IFN-gamma.
pubmed:affiliation
Department of Microbiology, The Ohio State University, Columbus, Ohio, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't