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The role of Hfe in transferrin-bound iron uptake by hepatocytes

Chua, A.C.G., Herbison, C.E., Drake, S.F., Graham, R.M., Olynyk, J.K. and Trinder, D. (2008) The role of Hfe in transferrin-bound iron uptake by hepatocytes. Hepatology, 47 (5). pp. 1737-1744.

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Link to Published Version: http://dx.doi.org/10.1002/hep.22180
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Abstract

HFE-related hereditary hemochromatosis results in hepatic iron overload. Hepatocytes acquire transferrin-bound iron via transferrin receptor (Tfr) 1 and Tfr1-independent pathways (possibly Tfr2-mediated). In this study, the role of Hfe in the regulation of hepatic transferrin-bound iron uptake by these pathways was investigated using Hfe knockout mice. Iron and transferrin uptake by hepatocytes from Hfe knockout, non–iron-loaded and iron-loaded wild-type mice were measured after incubation with 50 nM 125I-Tf-59Fe (Tfr1 pathway) and 5 μM 125I-Tf-59Fe (Tfr1-independent or putative Tfr2 pathway). Tfr1 and Tfr2 messenger RNA (mRNA) and protein expression were measured by real-time polymerase chain reaction and western blotting, respectively. Tfr1-mediated iron and transferrin uptake by Hfe knockout hepatocytes were increased by 40% to 70% compared with iron-loaded wild-type hepatocytes with similar iron levels and Tfr1 expression. Iron and transferrin uptake by the Tfr1-independent pathway was approximately 100-fold greater than by the Tfr1 pathway and was not affected by the absence of Hfe. Diferric transferrin increased hepatocyte Tfr2 protein expression, resulting in a small increase in transferrin but not iron uptake by the Tfr1-independent pathway. Conclusion: Tfr1-mediated iron uptake is regulated by Hfe in hepatocytes. The Tfr1-independent pathway exhibited a much greater capacity for iron uptake than the Tfr1 pathway but it was not regulated by Hfe. Diferric transferrin up-regulated hepatocyte Tfr2 protein expression but not iron uptake, suggesting that Tfr2 may have a limited role in the Tfr1-independent pathway.

Item Type: Journal Article
Publisher: John Wiley & Sons Inc.
Copyright: © 2008 American Association for the Study of Liver Diseases
URI: http://researchrepository.murdoch.edu.au/id/eprint/18405
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