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Iron‐ and inflammation‐induced hepcidin gene expression in mice is not mediated by Kupffer cells in vivo
Author(s) -
Lou DanQing,
Lesbordes JeanneClaire,
Nicolas Gaël,
Viatte Lydie,
Bennoun Myriam,
Van Rooijen Nico,
Kahn Axel,
Renia Laurent,
Vaulont Sophie
Publication year - 2005
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.20663
Subject(s) - hepcidin , inflammation , kupffer cell , in vivo , gene expression , microbiology and biotechnology , ferroportin , hepatology , regulation of gene expression , cytokine , biology , chemistry , immunology , medicine , gene , biochemistry
Hepcidin, a recently discovered iron regulatory peptide, is believed to inhibit the release of iron from absorptive enterocytes and macrophages. Liver hepcidin synthesis is induced in vivo by iron stores and inflammation. The molecular basis of the regulation of hepcidin gene expression by these effectors in hepatocytes is currently unknown, although there is strong evidence that indirect mechanisms are involved. The aims of this study were to gain insight into these mechanisms and to determine to what extent other liver cell types are responsible for transducing the signal by which hepcidin expression is regulated in mouse hepatocytes. For this, we depleted Kupffer cells by injection of liposome‐encapsulated clodronate and then studied iron‐ and inflammation‐induced hepcidin gene expression. In addition, we directly evaluated the role of the inflammatory cytokine interleukin 6 (IL‐6) by using IL‐6–deficient mice. Our results show that iron is able to induce hepcidin gene expression independently of Kupffer cells in the liver and circulating IL‐6. In contrast, we show that hepcidin gene induction by inflammation is also independent of Kupffer cells, but involves, at least partly, IL‐6. In conclusion , these results show that two independent regulatory pathways control hepcidin gene expression and suggest that hepatocytes play a key role in the regulation of hepcidin gene expression by sensing iron and inflammatory signals. (H EPATOLOGY 2005.)