IRON TRANSPORT IN A MURINE MODEL OF HEMOCHROMATOSIS

小鼠血色素沉着症模型中的铁转运

• 批准号: 6390950
• 负责人: Robert E Fleming
• 金额: $ 22.2万
• 依托单位: SAINT LOUIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6390950
• 关键词: dietary iron; disease /disorder model; duodenum; gastrointestinal nutrient absorption; gene targeting; genetically modified animals; hereditary hemochromatosis; intestinal villi; iron metabolism; laboratory mouse; model design /development; nuclear runoff assay; nutrition related tag; transferrin receptor

DESCRIPTION (adapted from the application) Hereditary hemochromatosis (HH) is a common autosomal recessive disorder of iron metabolism characterized by excess absorption of dietary iron. HH is caused by mutation of HFE, a MHC class I-like protein found in stable association with Beta-2-microglobulin and transferrin receptor in duodenal crypt cells. An essential role for HFE in regulating dietary iron absorption was confirmed by our observation that HFE knockout mice manifest excess iron loading. The mechanism by which HFE modulates intestinal iron absorption is unknown. Our working hypothesis is that disruption of HFE 1) decreases the uptake and/or increases the release of plasma iron by duodenal crypt cells, and thereby 2) decreases the crypt cell regulatory iron pool, which 3) increases apical expression of the iron transporter DMT1 in daughter enterocytes, which in turn, 4) increases dietary iron uptake. Our broad goal is to understand the mechanism by which HFE modulates dietary iron transport. We will pursue this goal by testing each step of the working hypothesis using two novel murine models-one in which the HFE gene has been disrupted, and the other in which it has been overexpressed. Two control groups with normal HFE alleles will be analyzed-one group iron-deficient and the other iron-replete. In the proposed studies on HFE knockout and overexpressing mice (and controls with normal alleles) we have 4 specific aims: 1) Measure the uptake and release of transferrin-bound and ionic iron by duodenal crypt cells. 2) Quantify iron-responsive element binding activity along the duodenal crypt-villus axis. 3) Characterize DMT1 mRNA and protein expression in duodenal enterocytes. 4) Measure duodenal iron uptake and transfer. These studies should improve our understanding of the pathogenesis of HH by defining the molecular events regulating dietary iron absorption and the consequences of functional loss of HFE. We hope the findings suggest novel approaches to prevent iron loading in HH and other diseases with excess dietary iron absorption.

描述（改编自应用程序） 遗传性血色病（HH）是一种常见的常染色体隐性遗传病， 以过量吸收食物中的铁为特征的铁代谢。HH是 由HFE突变引起，HFE是一种稳定的MHC I类蛋白， 十二指肠β_2-微球蛋白和转铁蛋白受体的关系 隐窝细胞HFE在调节膳食铁吸收中的重要作用 我们观察到HFE敲除小鼠表现出过量的铁， 加载中HFE调节肠铁吸收的机制是 未知我们的工作假设是，破坏HFE 1）降低了 通过十二指肠隐窝细胞摄取和/或增加血浆铁的释放，和 从而2）减少隐窝细胞调节铁池，3）增加 铁转运蛋白DMT 1在子代肠细胞中的顶端表达， 反过来，4）增加膳食铁的吸收。我们的主要目标是了解 HFE调节膳食铁转运的机制。我们会追查下去 通过使用两种新的小鼠模型测试工作假设的每一步， 模型-其中一个HFE基因已被破坏，另一个， 被过度表达了两个具有正常HFE等位基因的对照组将 分析一组缺铁和另一组充满铁。拟议 对HFE敲除和过表达小鼠（以及正常对照）的研究 我们有4个具体目标： 1)通过以下方法测量转铁蛋白结合铁和离子铁的摄取和释放： 十二指肠隐窝细胞 2)定量沿十二指肠沿着的铁反应元件结合活性 隐窝绒毛轴 3)表征十二指肠肠细胞中DMT 1 mRNA和蛋白表达。 4)测量十二指肠铁摄取和转移。 这些研究应该通过以下方式提高我们对HH发病机制的理解： 定义调节膳食铁吸收的分子事件和 HFE功能丧失的后果。我们希望这些发现能提供新的建议， 预防HH和其他疾病中铁负荷的方法 铁吸收