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  • Hepcidin Is Down-regulated ...
    Bridle, KimR; Cheung, Ting-Kin; Murphy, ThereseL; Walters, MargaretM; Anderson, GregoryJ; Crawford, DarrellH. G.; Fletcher, Linda M.

    Alcoholism, clinical and experimental research, 01/2006, Letnik: 30, Številka: 1
    Journal Article

    Background: Alcoholic liver disease is known to be associated with abnormal iron homeostasis, and iron metabolism itself is regulated by the liver‐derived peptide hepcidin. Both CCAAT enhancer binding protein alpha (C/EBPα) and interleukin 6 (IL‐6) have been shown to regulate hepcidin gene transcription. Aim: To investigate mechanisms underlying alcohol‐induced disturbances in iron homeostasis by measuring the expression of hepcidin and C/EBPα mRNA using in vivo and in vitro models of alcoholic liver injury. Methods: Male rats were pair‐fed an alcoholic liquid diet for 12 weeks. RT‐PCR was performed on liver tissue using specific primers for hepcidin and C/EBPα. The effect of alcohol on hepcidin and C/EBPα gene expression was also determined in isolated hepatocytes, HuH‐7 cells and HepG2 cells treated with 50 mM ethanol, 200 μM acetaldehyde, and/or 20 ng/ml IL‐6. Results: Hepcidin and C/EBPα mRNA expression were significantly decreased in alcohol‐fed rats compared with pair‐fed controls (6‐fold p<0.001 and 2.2‐fold p<0.0002 reduction, respectively) and hepatic lipid peroxidation was increased by 32.5% (p<0.05) in alcohol‐fed rats compared with controls. Hepcidin gene expression was not altered significantly in cells cultured in the presence of 50 mM ethanol. Following 24 hour stimulation by IL‐6, there was a 4‐fold increase in hepcidin expression in hepatocytes and a 9‐fold increase in HuH‐7 cells. Ethanol (50 mM) attenuated the IL‐6‐induced increase in hepcidin expression in HuH‐7 cells (9‐fold to a 4‐fold increase) but not in hepatocytes. Acetaldehyde had no effect on hepcidin gene expression in cells in culture. Conclusion: The down‐regulation of hepcidin and C/EBPα gene expression shown in vivo implies disturbed iron sensing contributing to the hepatosiderosis seen in alcoholic liver disease, possibly by mechanisms involving the IL‐6 signaling cascade.