Regulation of mammalian iron homeostasis by iron and transferrin

铁和转铁蛋白对哺乳动物铁稳态的调节

• 批准号: 7707314
• 负责人: Thomas Benedict Bartnikas
• 金额: $ 13.23万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7707314
• 关键词: Affinity; Anabolism; Anemia; Binding; Binding Proteins; Biological Assay; Bone Marrow Ablation; Breeding; Cell Line; Cells; Data; Defect; Disease; Erythroid; Gene Expression; Goals; Health; Hepatocyte; Homeostasis; Hormones; Human; In Transferrin; In Vitro; Iron; Lead; Liver; Mammalian Cell; Manganese; Measures; Mediating; Mentors; Metals; Modeling; Mus; Pathway interactions; Peptides; Phase; Principal Investigator; Recycling; Regulation; Research; Resistance; Role; SLC11A2 gene; Serum; Severities; Tissues; Transferrin; Transferrin-Binding Proteins; Transgenic Mice; Variant; Work; World Health; absorption; cDNA Library; design; diferric transferrin; hepcidin; in vivo; interest; macrophage; mutant; novel; public health relevance; research study; small hairpin RNA; trend

DESCRIPTION (provided by applicant): As iron (Fe)-related disorders are prevalent world-wide, understanding Fe homeostasis is critical to understanding human health. Fe homeostasis is largely regulated by hepcidin, a liver-derived peptide that inhibits dietary Fe absorption and macrophage Fe recycling. Hepcidin expression is inhibited and stimulated respectively by increased erythropoietic drive and Fe overload. Focused on identifying soluble regulators of hepcidin expression, my current work has implicated transferrin (TF), the abundant serum metal-binding protein, and manganese (Mn), an essential TF-bound metal, in the regulation of hepcidin expression. My first objective, to be completed during the mentored phase, is to determine the effect of TF on hepcidin expression in vivo. I will construct transgenic mice expressing TF variants with altered metal affinity, breed them onto a TF-deficient background and evaluate hepcidin expression before and after bone marrow ablation to minimize the inhibition of hepcidin expression by erythropoietic drive. The second objective, to be initiated during the mentored phase, is to identify commonalities and divergences between cellular Mn and Fe homeostasis as a means to further dissect Fe homeostasis. I will assay 54Mn and 55Fe transport in cell lines with altered levels of known metal transporters and determine the effect of altered Mn and Fe levels on 54Mn and 55Fe transport and incorporation into TF. The third objective, the focus of the independent phase, is to identify novel factors required for cellular metal homeostasis. As high Mn levels are toxic to many cell lines, I will alter cellular gene expression with shRNA and cDNA libraries, select for cells resistant to high Mn levels and identify mutant lines of interest by 54Mn and 55Fe transport assay. From the first two objectives, I will achieve proficiency in the study of Fe transport and distribution; from the last two objectives, I will establish an independent focus divergent from my mentor's, the role of iron in hematologic disorders. This proposal reflects the overall trend in my research-the study of mammalian metal homeostasis and its relation to human health and disease-and will lead to a paradigm of metal homeostasis from which novel treatments for metal-related disorders can be designed. PUBLIC HEALTH RELEVANCE: The goal of this study is to determine how iron in the body stimulates the liver to produce a hormone that limits iron absorption from the gut. The results of this research should offer novel treatment options for iron-related disorders such as anemia.

描述（由申请人提供）： 由于铁（Fe）相关疾病在世界范围内普遍存在，因此了解Fe稳态对了解人类健康至关重要。铁稳态在很大程度上受铁调素调节，铁调素是一种肝源性肽，可抑制膳食铁吸收和巨噬细胞铁再循环。铁调素的表达分别被增加的红细胞生成驱动和铁超载抑制和刺激。专注于确定铁调素表达的可溶性调节剂，我目前的工作涉及转铁蛋白（TF），丰富的血清金属结合蛋白，和锰（Mn），一个必不可少的TF结合金属，铁调素表达的调节。我的第一个目标是在指导阶段完成，是确定TF对体内hepcidin表达的影响。我将构建转基因小鼠表达TF变异体改变金属亲和力，将它们繁殖到TF缺乏的背景和评估骨髓消融前后的铁调素表达，以尽量减少红细胞生成驱动对铁调素表达的抑制。第二个目标，在指导阶段开始，是确定细胞锰和铁稳态之间的共性和分歧，作为一种手段，以进一步剖析铁稳态。我将在已知金属转运蛋白水平改变的细胞系中测定54 Mn和55 Fe转运，并确定改变的Mn和Fe水平对54 Mn和55 Fe转运和掺入TF的影响。第三个目标，独立阶段的重点，是确定细胞金属稳态所需的新因素。由于高Mn水平对许多细胞系是有毒的，我将用shRNA和cDNA文库改变细胞基因表达，选择对高Mn水平有抗性的细胞，并通过54 Mn和55 Fe转运测定鉴定感兴趣的突变株。从前两个目标，我将达到熟练的铁运输和分布的研究;从最后两个目标，我将建立一个独立的重点不同于我的导师的，铁在血液系统疾病中的作用。这一建议反映了我的研究的总体趋势哺乳动物金属稳态及其与人类健康和疾病的关系的研究，并将导致一个范例的金属稳态，从新的治疗金属相关的疾病可以设计。 公共卫生相关性：这项研究的目的是确定体内的铁如何刺激肝脏产生一种激素，限制肠道对铁的吸收。这项研究的结果应该为铁相关疾病如贫血提供新的治疗选择。