Potential conflicts of interest: Nothing to report.
Hepatocyte divalent metal-ion transporter-1 is dispensable for hepatic iron accumulation and non-transferrin-bound iron uptake in mice
Article first published online: 1 JUL 2013
Copyright © 2013 by the American Association for the Study of Liver Diseases
Volume 58, Issue 2, pages 788–798, August 2013
How to Cite
Wang, C.-Y. and Knutson, M. D. (2013), Hepatocyte divalent metal-ion transporter-1 is dispensable for hepatic iron accumulation and non-transferrin-bound iron uptake in mice. Hepatology, 58: 788–798. doi: 10.1002/hep.26401
This work was supported by the National Institutes of Health (grant no.: R01 DK080706; to M.D.K.) and the International Life Sciences Institute North America Future Leader Award (to M.D.K.). The authors graciously thank the late Dr. Hiromi Gunshin and Dr. Nancy Andrews (Duke University School of Medicine, Durham, NC) for providing the mutant mice used in these studies, and Dr. Philippe Gros (Mcgill University, Montreal, Canada) for the auto-OMT1 antiserum.
- Issue published online: 29 JUL 2013
- Article first published online: 1 JUL 2013
- Accepted manuscript online: 19 MAR 2013 12:43AM EST
- Manuscript Accepted: 14 MAR 2013
- Manuscript Received: 13 SEP 2012
Divalent metal-ion transporter-1 (DMT1) is required for iron uptake by the intestine and developing erythroid cells. DMT1 is also present in the liver, where it has been implicated in the uptake of transferrin-bound iron (TBI) and non-transferrin-bound iron (NTBI), which appears in the plasma during iron overload. To test the hypothesis that DMT1 is required for hepatic iron uptake, we examined mice with the Dmt1 gene selectively inactivated in hepatocytes (Dmt1liv/liv). We found that Dmt1liv/liv mice and controls (Dmt1flox/flox) did not differ in terms of hepatic iron concentrations or other parameters of iron status. To determine whether hepatocyte DMT1 is required for hepatic iron accumulation, we crossed Dmt1liv/liv mice with Hfe−/− and hypotransferrinemic (Trfhpx/hpx) mice that develop hepatic iron overload. Double-mutant Hfe−/−Dmt1liv/liv and Trfhpx/hpx;Dmt1liv/liv mice were found to accumulate similar amounts of hepatic iron as did their respective controls. To directly assess the role of DMT1 in NTBI and TBI uptake, we injected 59Fe-labeled ferric citrate (for NTBI) or 59Fe-transferrin into plasma of Dmt1liv/liv and Dmt1flox/flox mice and measured uptake of 59Fe by the liver. Dmt1liv/liv mice displayed no impairment of hepatic NTBI uptake, but TBI uptake was 40% lower. Hepatic levels of transferrin receptors 1 and 2 and ZRT/IRT-like protein 14, which may also participate in iron uptake, were unaffected in Dmt1liv/liv mice. Additionally, liver iron levels were unaffected in Dmt1liv/liv mice fed an iron-deficient diet. Conclusion: Hepatocyte DMT1 is dispensable for hepatic iron accumulation and NTBI uptake. Although hepatocyte DMT1 is partially required for hepatic TBI uptake, hepatic iron levels were unaffected in Dmt1liv/liv mice, suggesting that this pathway is a minor contributor to the iron economy of the liver. (Hepatology 2013;58:788–798)