title: Increased hepcidin in transferrin-treated thalassemic mice correlates with increased liver BMP2 expression and decreased hepatocyte ERK activation.
abstract: Iron overload results in significant morbidity and mortality in β-thalassemic patients. Insufficient hepcidin is implicated in parenchymal iron overload in β-thalassemia and approaches to increase hepcidin have therapeutic potential. We have previously shown that exogenous apo-transferrin markedly ameliorates ineffective erythropoiesis and increases hepcidin expression in Hbb(th1/th1) (thalassemic) mice. We utilize in vivo and in vitro systems to investigate effects of exogenous apo-transferrin on Smad and ERK1/2 signaling, pathways that participate in hepcidin regulation. Our results demonstrate that apo-transferrin increases hepcidin expression in vivo despite decreased circulating and parenchymal iron concentrations and unchanged liver Bmp6 mRNA expression in thalassemic mice. Hepatocytes from apo-transferrin-treated mice demonstrate decreased ERK1/2 pathway and increased serum BMP2 concentration and hepatocyte BMP2 expression. Furthermore, hepatocyte ERK1/2 phosphorylation is enhanced by neutralizing anti-BMP2/4 antibodies and suppressed in vitro in a dose-dependent manner by BMP2, resulting in converse effects on hepcidin expression, and hepatocytes treated with MEK/ERK1/2 inhibitor U0126 in combination with BMP2 exhibit an additive increase in hepcidin expression. Lastly, bone marrow erythroferrone expression is normalized in apo-transferrin treated thalassemic mice but increased in apo-transferrin injected wild-type mice. These findings suggest that increased hepcidin expression after exogenous apo-transferrin is in part independent of erythroferrone and support a model in which apo-transferrin treatment in thalassemic mice increases BMP2 expression in the liver and other organs, decreases hepatocellular ERK1/2 activation, and increases nuclear Smad to increase hepcidin expression in hepatocytes.
authors.affiliation: Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA.
authors.forename: Huiyong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA.
authors.forename: Tenzin
authors.initials: T
authors.lastname: Choesang
authors.affiliation: Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA Central South University, Changsha, PR China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Li
authors.affiliation: Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA.
authors.forename: Shuming
authors.initials: S
authors.lastname: Sun
authors.affiliation: Flow Cytometry Core Laboratory, LFKRI, New York Blood Center, NY, USA.
authors.forename: Petra
authors.initials: P
authors.lastname: Pham
authors.affiliation: Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA.
authors.forename: Weili
authors.initials: W
authors.lastname: Bao
authors.affiliation: Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA University of Piemonte Orientale, Amedeo Avogadro, Novara, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Feola
authors.affiliation: Intrinsic Lifesciences, LLC, La Jolla, CA, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Westerman
authors.affiliation: Central South University, Changsha, PR China.
authors.forename: Guiyuan
authors.initials: G
authors.lastname: Li
authors.affiliation: University of Piemonte Orientale, Amedeo Avogadro, Novara, Italy.
authors.forename: Antonia
authors.initials: A
authors.lastname: Follenzi
authors.affiliation: The Feinstein Institute for Medical Research, Manhasset, NY, USA.
authors.forename: Lionel
authors.initials: L
authors.lastname: Blanc
authors.affiliation: Weill Cornell Medical College, NY, USA.
authors.forename: Stefano
authors.initials: S
authors.lastname: Rivella
authors.affiliation: Saint Louis University, MO, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Fleming
authors.affiliation: Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA yginzburg@nybloodcenter.org.
authors.forename: Yelena Z
authors.initials: YZ
authors.lastname: Ginzburg
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D001059:Apoproteins / Q000494:pharmacology*; D055396:Bone Morphogenetic Protein 2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D055418:Bone Morphogenetic Protein 6 / Q000235:genetics / Q000378:metabolism; D002070:Butadienes / Q000494:pharmacology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D064451:Hepcidins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism; D014168:Transferrin / Q000494:pharmacology*; D017086:beta-Thalassemia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
chemical_list: D057134:Antibodies, Neutralizing; D001059:Apoproteins; C525719:Bmp2 protein, mouse; C525817:Bmp6 protein, mouse; D055396:Bone Morphogenetic Protein 2; D055418:Bone Morphogenetic Protein 6; D002070:Butadienes; D016207:Cytokines; C572502:Erfe protein, mouse; C579599:Hamp protein, mouse; D064451:Hepcidins; D009124:Muscle Proteins; D009570:Nitriles; D012333:RNA, Messenger; D051785:Smad Proteins; D014168:Transferrin; C113580:U 0126; C028284:apotransferrin; C535148:Mapk1 protein, mouse; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3