Myoglobin as a Nitrite Reductase that Regulates Hypoxic Cardiac NO Signaling

肌红蛋白作为亚硝酸盐还原酶调节缺氧心脏 NO 信号传导

基本信息

批准号：
7881340
负责人：
Mark T Gladwin
金额：
$ 40.46万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
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：
2010-04-15 至 2014-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7881340
关键词：
Address Aerobic Exercise Anions Apoptosis Apoptotic Binding Biochemical Biogenesis Biological Availability Biological Process Cardiac Cardiac Myocytes Cardiovascular system Cell Culture System Cell Culture Techniques Cell Death Cells Chemicals Chemistry Clinical Trials Complex Cytoprotection Diet Down-Regulation Electron Transport Environment Event Gap Junctions Gene Proteins Generations Globin Health Heart Heme Heme Group Hemeproteins Hemoglobin Histidine Hypoxia In Vitro Intravenous Iron Ischemia Knock-out Knockout Mice Mediating Mediterranean Diet Metabolism Mitochondria Modeling Modification Molecular Molecular Target Mus Myocardial Infarction Myoglobin NADH dehydrogenase (ubiquinone)Nitrates Nitric Oxide Nitrite Reductase Nitrites Nitrogen Oxides Nitrosation Oxidation-Reduction Oxidoreductase Oxygen Oxygen measurement, partial pressure, arterial Pathway interactions Phenotype Physiological Property Proteins Protons Publishing Reaction Reactive Oxygen Species Recombinants Regulation Reperfusion Injury Reperfusion Therapy Research Research Proposals Respiration Respiratory Chain Rest Role Signal Pathway Signal Transduction Source Stream Stress Subfamily lentivirinae Sulfhydryl Compounds Supplementation System Testing Tissues Work base biological adaptation to stress cellular targeting clinically relevant complex IV cytotoxicity dietary nitrate heart cell heme a in vivo in vivo Model insight loss of function mouse model mutant nitric oxide reductase novel programs public health relevance resilience response

项目摘要

DESCRIPTION (provided by applicant): There is an emerging appreciation that heme proteins such as myoglobin and hemoglobin catalyze the metabolism of nitric oxide (NO) and nitrite, and thereby modulate cell and tissue responses to hypoxia. Over the last five years our group has published biochemical and physiological studies that suggest a novel function for hemoglobin as a nitrite reductase that generates NO under physiological and pathological hypoxia, suggesting that myoglobin, the other major heme globin, may also possess a capability to mediate the metabolism of oxides of nitrogen in a manner influenced by oxygen tension. Analogous to the bacterial nitrite reductases, a concerted proton and electron transfer reaction to nitrite reduces the anion to NO. We have also discovered a novel nitrite anhydrase activity that converts two nitrite molecules into the highly diffusible, nitrosating molecule N2O3, allowing efficient NO signaling in a heme rich environment. In the current research proposal, the NO/ N2O3 signaling pathways will be explored in myoglobin, with special focus on an ability to regulate cellular responses to hypoxic and ischemic stress by a) modulating cellular metabolism via the regulation of mitochondrial electron transfer reactions and b) activating net cytoprotective cell signaling reactions after ischemia-reperfusion injury. These concepts will be addressed by testing the hypothesis that myoglobin-mediated nitrite metabolism regulates hypoxic NO signaling and promotes NO bioavailability in the heart. More specifically, using mutant myoglobin proteins in in vitro biochemical and cell culture systems as well as an in vivo model of myocardial infarction, we aim 1) to determine the molecular and enzymatic mechanisms underlying the nitrite reductase activity of myoglobin in hypoxia, 2) define critical molecular targets of myoglobin-derived NO and N2O3, and 3) to determine the role of myoglobin in regulating downstream cytoprotective signaling (apoptosis and mitochondrial biogenesis) after ischemia/reperfusion. Successful completion of the proposed research plan will advance our understanding of the biological function of myoglobin and the physiological and pharmacological potential of nitrite in the cardiovascular system. PUBLIC HEALTH RELEVANCE: After a heart attack, part of the tissue in the heart dies. A heart protein called myoglobin can convert nitrite, a chemical found in the diet, to nitric oxide, a chemical that protects heart cells from death. This project will investigate how nitrite and myoglobin work together so that nitrite can be used to protect the heart during a heart attack.

描述（由申请人提供）：人们逐渐认识到血红蛋白（如肌红蛋白和血红蛋白）可催化一氧化氮（NO）和亚硝酸盐的代谢，从而调节细胞和组织对缺氧的反应。在过去的五年里，我们小组发表的生化和生理学研究表明，血红蛋白作为亚硝酸还原酶具有一种新功能，可以在生理和病理缺氧下产生一氧化氮，这表明肌红蛋白（另一种主要血红素球蛋白）也可能具有介导氮氧化物的代谢受氧张力的影响。与细菌亚硝酸还原酶类似，亚硝酸盐的协同质子和电子转移反应将阴离子还原为 NO。我们还发现了一种新的亚硝酸盐脱水酶活性，可将两个亚硝酸盐分子转化为高度扩散的亚硝化分子 N2O3，从而在富含血红素的环境中实现有效的 NO 信号传导。在当前的研究计划中，将探索肌红蛋白中的 NO/ N2O3 信号通路，特别关注通过 a) 通过调节线粒体电子转移反应来调节细胞代谢和 b) 调节细胞对缺氧和缺血应激反应的能力。缺血再灌注损伤后激活净细胞保护细胞信号反应。这些概念将通过测试肌红蛋白介导的亚硝酸盐代谢调节缺氧 NO 信号传导并促进心脏中 NO 生物利用度的假设来解决。更具体地说，在体外生化和细胞培养系统以及心肌梗塞的体内模型中使用突变型肌红蛋白，我们的目标是 1) 确定缺氧条件下肌红蛋白亚硝酸还原酶活性的分子和酶机制，2) 定义肌红蛋白衍生的 NO 和 N2O3 的关键分子靶标，以及 3) 确定肌红蛋白在调节下游细胞保护信号（细胞凋亡和线粒体生物发生）中的作用缺血/再灌注。拟议研究计划的成功完成将增进我们对肌红蛋白的生物学功能以及亚硝酸盐在心血管系统中的生理和药理潜力的理解。公共卫生相关性：心脏病发作后，心脏的部分组织会死亡。一种称为肌红蛋白的心脏蛋白质可以将亚硝酸盐（饮食中发现的一种化学物质）转化为一氧化氮（一种保护心脏细胞免于死亡的化学物质）。该项目将研究亚硝酸盐和肌红蛋白如何协同工作，以便在心脏病发作时使用亚硝酸盐来保护心脏。