Lobe specificity of iron binding to transferrin modulates murine erythropoiesis and iron homeostasis

Nermi L. Parrow, Yihang Li, Maria Feola, Amaliris Guerra, Carla Casu, Princy Prasad, Luke Mammen, Faris Ali, Edvinas Vaicikauskas, Stefano Rivella, Yelena Z. Ginzburg, Robert E. Fleming

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Transferrin, the major plasma iron-binding molecule, interacts with cell-surface receptors to deliver iron, modulates hepcidin expression, and regulates erythropoiesis. Transferrin binds and releases iron via either or both of 2 homologous lobes (N and C). To test the hypothesis that the specificity of iron occupancy in the N vs C lobe influences transferrin function, we generated mice with mutations to abrogate iron binding in either lobe (TfN-bl or TfC-bl). Mice homozygous for either mutation had hepatocellular iron loading and decreased liver hepcidin expression (relative to iron concentration), although to different magnitudes. Both mouse models demonstrated some aspects of iron-restricted erythropoiesis, including increased zinc protoporphyrin levels, decreased hemoglobin levels, and microcytosis. Moreover, the TfN-bl/N-bl mice demonstrated the anticipated effect of iron restriction on red cell production (ie, no increase in red blood cell [RBC] count despite elevated erythropoietin levels), along with a poor response to exogenous erythropoietin. In contrast, the TfC-bl/C-bl mice had elevated RBC counts and an exaggerated response to exogenous erythropoietin sufficient to ameliorate the anemia. Observations in heterozygous mice further support a role for relative N vs C lobe iron occupancy in transferrinmediated regulation of iron homeostasis and erythropoiesis.

Original languageEnglish
Pages (from-to)1373-1384
Number of pages12
JournalBlood
Volume134
Issue number17
DOIs
StatePublished - 24 Oct 2019

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