Understand and Improve Iron Distribution and Erythropoiesis in Beta-Thalassemia

了解并改善β地中海贫血的铁分布和红细胞生成

基本信息

批准号：
8228015
负责人：
Yelena Ginzburg
金额：
$ 13.23万
依托单位：
NEW YORK BLOOD CENTER
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-02-15 至 2016-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8228015
关键词：
Address Affect Anemia Apoptosis Award Binding Blood Circulation Bone Marrow Cell Survival Cell physiology Cells Clinical Cytosol Data Deposition Development Disease Equilibrium Erythrocytes Erythroid Erythroid Cells Erythropoiesis Erythropoietin Evaluation Extramedullary Foundations Functional disorder Generations Genetic Transcription Globin Goals Hematopoietic Heme Heme Iron Hemoglobin Human Human Cell Line In Transferrin In Vitro Intestines Iron Iron Overload K-562 Laboratories Measures Medicine Mentors Methods Morbidity - disease rate Mus Patients Phenotype Physiology Play Principal Investigator Production Recycling Regulation Relative (related person)Reticulocytosis Role Sampling Scientist Serum Spleen Splenomegaly Staging Testing Thalassemia Therapeutic Toxic effect Training Programs Transferrin Transferrin Receptor Transfusion Translations absorption alpha Globin alternative treatment beta Globin beta Thalassemia career chelation diferric transferrin disease phenotype erythroid differentiation heme 1 hepcidin human TFRC protein human disease improved in vivo insight iron metabolism mortality pre-clinical programs public health relevance therapeutic development uptake zinc protoporphyrin

项目摘要

DESCRIPTION (provided by applicant): This application describes a five-year mentored training program to develop an independent clinician-scientist whose career in academic medicine will focus on furthering our understanding of human red blood cell development. Beta-thalassemia in humans is a disease associated with anemia, splenomegaly, and ineffective erythropoiesis; iron overload in this disease results from transfusion and increased iron absorption from hepcidin deficiency. Our lab previously demonstrated that treatment with transferrin in mice with beta- thalassemia improves the disease phenotype with reversal of anemia, splenomegaly, and ineffective erythropoiesis and an increase in hepcidin expression. Surprisingly, although there are more red cells in circulation, their size and hemoglobin content is reduced in treated mice. We hypothesize that supplemental transferrin results in more iron deficient erythropoiesis, reducing the imbalance between heme, alpha-globin, and beta-globin synthesis in beta-thalassemia. My goal in the studies proposed for this award is to test this hypothesis. I plan two specific aims to evaluate this: 1) to determine if iron uptake by erythroid precursors is altered when additional transferrin is available in vivo and in vitro; and 2) to determine if the regulation and production of hemoglobin components as well as iron and heme export is altered when supplemental transferrin is added in normal and beta-thalassemic cells in vivo and in vitro. These studies will test my hypothesis that exogenous transferrin restricts iron entry into erythroid precursors and protects early erythroid cells from heme toxicity, will provide insight into the physiology responsible for the phenotype in beta- thalassemia, and will further our understanding of normal and disordered erythropoiesis. I will accomplish these specific aims by the following methods: 1) characterize the ferrokinetics of erythroid precursors in mice given additional transferrin, analyze the expression of transferrin receptor in these cells in vivo, and evaluate cytosolic iron uptake in cell lines and human cells in culture; 2) evaluate expression levels and regulators of heme and globin production, measure levels of zinc protoporphyrin and free heme in the cytosol, and characterize the effect on FLVCR and FPN-1B, heme and iron exporters, respectively, during erythroid precursor differentiation in mouse bone marrow and spleen samples as well as in human samples in culture. These studies focus on basic red blood cell physiology and may lend insight into human diseases where red blood cell development is disturbed. Lastly, progress in understanding mechanisms of transferrin efficacy in beta-thalassemic mice may enable its therapeutic development for patients with this disease. PUBLIC HEALTH RELEVANCE: Our laboratory previously demonstrated that using the main iron carrying molecule, transferrin, to treat mice with the disease, beta-thalassemia reverses many of the abnormalities present in this disease. We will systematically analyze the mechanisms underlying this effect in order to create a foundation for further testing of transferrin. The treatment for Beta-thalassemia is suboptimal, but has remained unchanged for the past fifty years. Ultimately, our goal is to provide an alternative treatment for these patients that could possibly be effective for other diseases associated with anemia and iron overload.

描述（由申请人提供）：本申请描述了一项为期五年的指导培训计划，旨在培养一名独立的临床医生科学家，其学术医学生涯将侧重于加深我们对人类红细胞发育的理解。人类β地中海贫血是一种与贫血、脾肿大和红细胞生成无效相关的疾病。这种疾病中的铁超载是由于输血和铁调素缺乏导致铁吸收增加造成的。我们的实验室之前证明，用转铁蛋白治疗β-地中海贫血小鼠可改善疾病表型，逆转贫血、脾肿大和无效红细胞生成，并增加铁调素表达。令人惊讶的是，尽管循环中有更多的红细胞，但在接受治疗的小鼠中，它们的大小和血红蛋白含量却有所减少。我们假设补充转铁蛋白会导致更多的缺铁性红细胞生成，从而减少β-地中海贫血中血红素、α-珠蛋白和β-珠蛋白合成之间的不平衡。我申请该奖项的研究目标是检验这一假设。我计划有两个具体目标来评估这一点：1）确定当体内和体外有额外的转铁蛋白时，红系前体细胞对铁的吸收是否会发生改变； 2) 确定在正常细胞和β-地中海贫血细胞体内和体外添加补充转铁蛋白时，血红蛋白成分的调节和产生以及铁和血红素输出是否会发生改变。这些研究将检验我的假设，即外源性转铁蛋白限制铁进入红系前体细胞并保护早期红系细胞免受血红素毒性，将深入了解导致β-地中海贫血表型的生理学，并将进一步加深我们对正常和紊乱红细胞生成的理解。我将通过以下方法实现这些具体目标：1）表征给予额外转铁蛋白的小鼠中红系前体的铁动力学，分析体内这些细胞中转铁蛋白受体的表达，并评估培养的细胞系和人类细胞中的胞质铁摄取; 2) 评估血红素和球蛋白产生的表达水平和调节因子，测量细胞质中锌原卟啉和游离血红素的水平，并表征在小鼠骨红系前体分化过程中分别对FLVCR和FPN-1B、血红素和铁输出蛋白的影响骨髓和脾脏样本以及培养的人类样本。这些研究重点关注基本的红细胞生理学，可能有助于深入了解红细胞发育受到干扰的人类疾病。最后，在了解转铁蛋白在β地中海贫血小鼠中的功效机制方面取得的进展可能有助于其治疗这种疾病的患者的发展。公共健康相关性：我们的实验室先前证明，使用主要的铁携带分子转铁蛋白来治疗患有该疾病的小鼠，β-地中海贫血可以逆转该疾病中存在的许多异常。我们将系统分析这种效应的机制，为进一步检测转铁蛋白奠定基础。 β-地中海贫血的治疗效果欠佳，但在过去五十年中一直保持不变。最终，我们的目标是为这些患者提供一种替代疗法，这种疗法可能对与贫血和铁超载相关的其他疾病有效。