Article first published online: 24 AUG 2011
Copyright © 2011 American Association for the Study of Liver Diseases
Volume 54, Issue 5, pages 1800–1807, November 2011
How to Cite
Gkouvatsos, K., Wagner, J., Papanikolaou, G., Sebastiani, G. and Pantopoulos, K. (2011), Conditional disruption of mouse HFE2 gene: Maintenance of systemic iron homeostasis requires hepatic but not skeletal muscle hemojuvelin. Hepatology, 54: 1800–1807. doi: 10.1002/hep.24547
Potential conflict of interest: Nothing to report.
Supported by a grant from the Canadian Institutes for Health Research (CIHR; MOP-86515).
- Issue published online: 28 OCT 2011
- Article first published online: 24 AUG 2011
- Accepted manuscript online: 11 JUL 2011 12:30PM EST
- Manuscript Accepted: 29 JUN 2011
- Manuscript Received: 22 MAR 2011
Mutations of the HFE2 gene are linked to juvenile hemochromatosis, a severe hereditary iron overload disease caused by chronic hyperabsorption of dietary iron. HFE2 encodes hemojuvelin (Hjv), a membrane-associated bone morphogenetic protein (BMP) coreceptor that enhances expression of the liver-derived iron regulatory hormone hepcidin. Hjv is primarily expressed in skeletal muscles and at lower levels in the heart and the liver. Moreover, a soluble Hjv form circulates in plasma and is thought to act as a decoy receptor, attenuating BMP signaling to hepcidin. To better understand the regulatory function of Hjv, we generated mice with tissue-specific disruption of this protein in hepatocytes or in muscle cells. The hepatic ablation of Hjv resulted in iron overload, quantitatively comparable to that observed in ubiquitous Hjv−/− mice. Serum iron and ferritin levels, transferrin saturation, and liver iron content were significantly (P < 0.001) elevated in liver-specific Hjv−/− mice. Hepatic Hjv mRNA was undetectable, whereas hepcidin expression was markedly suppressed (12.6-fold; P < 0.001) and hepatic BMP6 mRNA up-regulated (2.4-fold; P < 0.01), as in ubiquitous Hjv−/− counterparts. By contrast, the muscle-specific disruption of Hjv was not associated with iron overload or altered hepcidin expression, suggesting that muscle Hjv mRNA is dispensable for iron metabolism. Our data do not support any significant iron-regulatory function of putative muscle-derived soluble Hjv in mice, at least under physiological conditions. Conclusion: The hemochromatotic phenotype of liver-specific Hjv−/− mice suggests that hepatic Hjv is necessary and sufficient to regulate hepcidin expression and control systemic iron homeostasis. (HEPATOLOGY 2011;)