Hepcidin and IL-1β.

Hepcidin expression is determined through transcriptional regulation by systemic iron status. However, acute or chronic inflammation also increases the expression of hepcidin, which is associated with the dysregulation of iron metabolism in pathological conditions. Interleukin (IL)-6 has been suggested to be a principal molecule to confer inflammation-related hepcidin transcription, which is mediated via signal transducer and activator of transcription (STAT)-binding site on the hepcidin promoter. Recently, it has been uncovered that another pro-inflammatory cytokine IL-1β stimulates hepcidin expression through the distinct mechanism underlying IL-6-mediated hepcidin transcription. In addition to IL-6 induction, IL-1β stimulates expression of CCAAT-enhancer-binding protein (C/EBP)δ, a transcription factor, leading to transcriptional activation of hepcidin via C/EBP-binding site on the hepcidin promoter. Thus, hepcidin transcription is stimulated through multiple elements in response to proinflammatory cytokines. Relationships between increased production of IL-1β and dysregulated iron metabolism have been suggested in various diseases, which may be linked to overproduction of hepcidin.