Molecular Mechanisms of the Hypoxic Response

缺氧反应的分子机制

基本信息

批准号：
8606199
负责人：
FRANK S LEE
金额：
$ 25.17万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-04-01 至 2015-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8606199
关键词：
Adult Anemia Biological Models Bone Marrow Cardiovascular system Chronic Kidney Failure Clinical Collaborations Complex Complication Coronary artery Coupled Disease End stage renal failure Enhancers Erythrocytes Erythrocytoses Erythropoietin Family Functional disorder Gene Expression Regulation Gene Targeting Genes Genetic Genetic Transcription Genetically Engineered Mouse Germ-Line Mutation Glycolysis Glycoproteins Hormones Human Hydroxylation Hypoxia Hypoxia Inducible Factor In Vitro Inherited Kidney Knockout Mice Knowledge Lead Life Liver Mammalian Cell Mediating Methods Missense Mutation Modeling Modification Molecular Mus Mutation Names Oxygen Oxygen measurement, partial pressure, arterial Pathway interactions Patients Physiology Post-Translational Protein Processing Procollagen-Proline Dioxygenase Production Protein Isoforms Proteins Rare Diseases Red Cell Mass result Regulation Role Site Tertiary Protein Structure Therapeutic Ubiquitin angiogenesis bHLH-PAS factor HLF base cerebrovascular chemotherapy egg glucose uptake human disease hypoxia inducible factor 1 in vitro Assay in vivo interest mouse model multicatalytic endopeptidase complex neoplastic oxygen-regulated proteins professor protein degradation public health relevance research study response tissue oxygenation transcription factor

项目摘要

DESCRIPTION (provided by applicant): The master regulator of the mammalian transcriptional response to hypoxia is the transcription factor Hypoxia Inducible Factor (HIF), the subunit of which is regulated at the level of protein turnover in an oxygen-sensitive manner. Under normoxic conditions, Prolyl Hydroxylase Domain protein (PHD) site- specifically hydroxylates HIF-(, which in turn targets HIF-( for degradation by the ubiquitin-proteasome pathway. Under hypoxic conditions, this posttranslational modification, which is inherently oxygen dependent, is inhibited, thereby allowing stabilization of HIF-(. HIF then upregulates a battery of genes involved in cellular, local, and systemic responses to hypoxia. The prototypical HIF target gene is that encoding for Erythropoietin (EPO), a glycoprotein hormone that regulates red blood cell mass in response to changes in oxygen tension. Thus, understanding HIF regulation will have implications for understanding and treating disorders of red blood cell mass regulation, such as anemia, which in turn is a significant complication seen in many clinical settings, including end stage renal disease and chemotherapy. More generally, hypoxia is a central feature of many human diseases, including coronary artery, cerebrovascular, and neoplastic disease, and therefore knowledge regarding HIF regulation will also impact our understanding of these diseases. There are three HIF-( isoforms (HIF-1(, HIF-2(, and HIF-3() and three Prolyl Hydroxylase Domain proteins (PHD1, PHD2, PHD3) that can hydroxylate them, raising the critical question of which isoforms are important for human physiology and pathophysiology. In collaboration with Professor Terence Lappin's group, we have identified a family with hereditary erythrocytosis (increased red blood cell mass) due to a G537W missense mutation in the HIF2A gene, and another family with erythrocytosis due to a P317R missense mutation in the PHD2 gene. These studies provide the first identification of hereditary mutations in any HIF or in any PHD isoform, and establish two new genetic causes of erythrocytosis. We have subsequently identified additional mutations in both genes. Our Specific Aims are to (1) study new erythrocytosis-associated HIF-2( and PHD2 mutations using in vitro assays in order to bolster our hypothesis that these proteins critically control EPO, (2) employ a Hif2a knockin mouse to model the human G537W missense mutation and examine functional consequences in vivo of dysregulation of Hif2-(, and (3) employ both a Phd2 knockin mouse for the P317R mutation, and a global conditional Phd2 knockout mouse to examine the mechanism by which Phd2 regulates red cell mass. Collectively, we anticipate that these studies will substantially increase our understanding of EPO regulation and, more broadly, our understanding of the mammalian oxygen sensing pathway.

描述（由申请人提供）：哺乳动物转录反应对缺氧的主要调节剂是转录因子缺氧诱导因子（HIF），其亚基的亚基以氧气敏感的方式在蛋白质周转水平下进行调节。在常氧条件下，丙基羟化酶结构蛋白（PHD）位点 - 特异性羟基（又针对HIF-（用于通过泛素蛋白 - 蛋白酶体途径降解）（在低氧条件下降解）对缺氧的细胞，局部和全身反应的基因。在许多临床环境中，包括末期肾脏疾病和化学疗法。共有三个HIF-（HIF-1（HIF-1（HIF-2（和HIF-3））和三个羟基羟化酶结构蛋白（PHD1，PHD2，PHD3）可以羟基羟基化，从而提出了哪些同种型的关键问题，即与人类的生理学和病理学杂志的杂物均具有重要的同种型。由于HIF2A基因的G537W错过突变引起的红细胞病（增加的红细胞质量），另一个由于PHD2基因中的p317r错义突变而导致的红细胞病，这些研究提供了对任何hif或phd中的首次识别。这两个基因的突变是（1）研究新的红细胞增生相关的HIF-2（使用体外测定的PHD2突变，以增强我们的假设，这些蛋白质严重控制EPO，（2）使用HIF2A敲击素来模拟人类G537W Mildsense ussense突变（Viv Infif）（VIV），使用PHD2敲击小鼠进行p317R突变，以及全局条件PHD2基因敲除小鼠检查PHD2调节红细胞量的机制。总体而言，我们预计这些研究将大大提高我们对EPO调节的理解，更广泛地了解我们对哺乳动物氧气感应途径的理解。