铁调素抵抗是由铁转运蛋白的血色素沉着症相关突变引起的。
Resistance to hepcidin is conferred by hemochromatosis-associated mutations of ferroportin.
作者信息
Drakesmith Hal, Schimanski Lisa M, Ormerod Emma, Merryweather-Clarke Alison T, Viprakasit Vip, Edwards Jon P, Sweetland Emma, Bastin Judy M, Cowley Diana, Chinthammitr Yingyong, Robson Kathryn J H, Townsend Alain R M
机构信息
Weatherall Institute of Molecular Medicine, Oxford. OX3 9DS, United Kingdom.
出版信息
Blood. 2005 Aug 1;106(3):1092-7. doi: 10.1182/blood-2005-02-0561. Epub 2005 Apr 14.
Ferroportin (FPN) mediates iron export from cells; FPN mutations are associated with the iron overloading disorder hemochromatosis. Previously, we found that the A77D, V162del, and G490D mutations inhibited FPN activity, but that other disease-associated FPN variants retained full iron export capability. The peptide hormone hepcidin inhibits FPN as part of a homeostatic negative feedback loop. We measured surface expression and function of wild-type FPN and fully active FPN mutants in the presence of hepcidin. We found that the Y64N and C326Y mutants of FPN are completely resistant to hepcidin inhibition and that N144D and N144H are partially resistant. Hemochromatosis-associated FPN mutations, therefore, either reduce iron export ability or produce an FPN variant that is insensitive to hepcidin. The former mutation type is associated with Kupffer-cell iron deposition and normal transferrin saturation in vivo, whereas patients with the latter category of FPN mutation have high transferrin saturation and tend to deposit iron throughout the liver parenchyma. FPN-linked hemochromatosis may have a variable pathogenesis depending on the causative FPN mutant.
铁转运蛋白(FPN)介导细胞内铁的输出;FPN突变与铁过载疾病血色素沉着症相关。此前,我们发现A77D、V162del和G490D突变会抑制FPN活性,但其他与疾病相关的FPN变体仍保留完全的铁输出能力。肽激素铁调素作为稳态负反馈回路的一部分抑制FPN。我们在有铁调素存在的情况下测量了野生型FPN和完全活性的FPN突变体的表面表达和功能。我们发现FPN的Y64N和C326Y突变体对铁调素抑制完全耐药,而N144D和N144H部分耐药。因此,与血色素沉着症相关的FPN突变要么降低铁输出能力,要么产生对铁调素不敏感的FPN变体。前一种突变类型与体内库普弗细胞铁沉积和正常转铁蛋白饱和度相关,而后者FPN突变类型的患者转铁蛋白饱和度高,且倾向于在整个肝实质内沉积铁。与FPN相关的血色素沉着症可能因致病的FPN突变体不同而有不同的发病机制。