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Mechanisms of Oxygen Sensing

氧传感机制

基本信息

批准号：
7805170
负责人：
Robert Brian Hamanaka
金额：
$ 5.05万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
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：
2010-09-13 至 2011-09-12
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7805170
关键词：
Altitude Anoxia Binding Blood flow Catalytic Domain Cells Complex Data Electron Transport Electron Transport Complex III Epidermis Erythropoiesis Erythropoietin Esthesia Family Gene Targeting Generations Genetic Programming Glycolysis Goals Heart Homeostasis Hydrogen Peroxide Hypoxia Hypoxia-Responsive Elements Individual Kidney Knock-out Lead Learning Liver Lung diseases Maintenance Malignant Neoplasms Measures Mediating Mitochondria Mixed Function Oxygenases Modeling Mus Organism Oxygen Phosphorylation Site Procollagen-Proline Dioxygenase Production Property Proteins Reactive Oxygen Species Regulation Reperfusion Injury Reporting Role Signaling Molecule Site Tertiary Protein Structure Testing Ubiquitination Up-Regulation Work angiogenesis cell growth regulation in vivo keratinocyte mortality mouse model mtTF1 transcription factor mutant prevent promoter response sensor transcription factor ubiquitin ligase

项目摘要

DESCRIPTION (provided by applicant): Proper regulation of the cellular response to hypoxia is of critical importance for the maintenance of cellular and organismal viability and function. Although much has been learned about the cellular hypoxic response in the last twenty years, several fundamental gaps in our understanding of oxygen sensing still exist. Our previous work has shown that production of mitochondrial Reactive Oxygen Species (ROS) during the hypoxic response is critical for the induction of the Hypoxia Inducible transcription Factor (HIF). It is unknown however, how mitochondria produce increased levels of ROS under conditions of low oxygen. We will test the ability of isolated mitochondria to produce ROS in response to low oxygen. Because our work has demonstrated that the QO site of mitochondrial complex III is critical for ROS production during hypoxia, we will also determine the ability of isolated mitochondrial complex III to produce ROS under conditions of low oxygen. Our preliminary data demonstrates that ROS regulate HIF through the inhibition of the Prolyl Hydroxylase Domain protein 2 (PHD2), which targets HIF for degradation. How ROS regulate PHD2 remains unknown. We will therefore examine the role of the amino-terminal (non-catalytic) domain of PHD2 In the regulation of PHD2 function during hypoxia. Previous reports suggest that this is an inhibitory regulatory domain, although the mechanism of inhibition is unexplored. Finally, we will create the first mouse model of mitochondrial oxygen sensing to demonstrate the role of mitochondrial ROS in HIF regulation in vivo. Epidermis acts as an oxygen sensor by regulating blood flow to the kidneys, which produce erythropoietin during hypoxia. We will therefore conditionally knock out the mitochondrial transcription factor TEAM in keratinocytes, thus depleting mitochondria and ROS production in these epidermal cells. We will then subject these mice to hypoxia to demonstrate the role of mitochondria as oxygen sensors in vivo. Relevance to Public Heath: While healthy individuals encounter hypoxia at high altitudes, pathological conditions of hypoxia arise during Ischemia-reperfusion injury, heart and lung disease, and cancer. Because these conditions represent major causes of mortality, further study of the mechanisms by which cells respond to hypoxia is needed. We will thus further explore the role of mitochondrial ROS in regulating the cellular hypoxic response.

描述（由申请人提供）：适当调节细胞对缺氧的反应对于维持细胞和生物体的活力和功能至关重要。虽然在过去的二十年里，我们对细胞缺氧反应有了很多了解，但在我们对氧感测的理解中仍然存在一些根本性的差距。我们以前的工作已经表明，在缺氧反应过程中，线粒体活性氧（ROS）的产生对于缺氧诱导转录因子（HIF）的诱导至关重要。然而，线粒体如何在低氧条件下产生增加的ROS水平尚不清楚。我们将测试分离的线粒体响应低氧产生ROS的能力。因为我们的工作已经证明，线粒体复合物III的QO位点是在缺氧过程中ROS产生的关键，我们还将确定分离的线粒体复合物III在低氧条件下产生ROS的能力。我们的初步数据表明，活性氧调节HIF通过抑制脯氨酰羟化酶结构域蛋白2（PHD2），其靶向HIF降解。ROS如何调节PHD2仍然未知。因此，我们将研究缺氧时PHD2的氨基末端（非催化）结构域在PHD2功能调节中的作用。以前的报告表明，这是一个抑制性的调节域，虽然抑制的机制是未知的。最后，我们将创建第一个线粒体氧传感的小鼠模型，以证明线粒体ROS在体内HIF调节中的作用。表皮通过调节流向肾脏的血液来充当氧传感器，肾脏在缺氧时产生促红细胞生成素。因此，我们将有条件地敲除角质形成细胞中的线粒体转录因子TEAM，从而耗尽这些表皮细胞中的线粒体和ROS产生。然后，我们将这些小鼠缺氧，以证明线粒体作为体内氧传感器的作用。与公共卫生的相关性：虽然健康个体在高海拔地区会遇到缺氧，但在缺血再灌注损伤、心脏和肺部疾病以及癌症期间会出现缺氧的病理状况。由于这些条件代表了死亡的主要原因，因此需要进一步研究细胞对缺氧的反应机制。因此，我们将进一步探讨线粒体活性氧在调节细胞缺氧反应中的作用。