Redox regulation in aging and failing heart

衰老和心脏衰竭中的氧化还原调节

• 批准号: 7919039
• 负责人: Junichi Sadoshima
• 金额: $ 15.53万
• 依托单位: UNIV OF MED/DENT OF NJ-NJ MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7919039
• 关键词: Acute; Address; Affect; Aging; Antioxidants; Apoptosis; Arts; Cardiac; Cardiac Myocytes; Cell Death; Cell Survival; Cell membrane; Cell physiology; Cells; Cessation of life; Congestive Heart Failure; Cysteine; Development; Down-Regulation; Enzymes; Extravasation; Functional disorder; Glycolysis; Growth; Heart; Heart Diseases; Heart Hypertrophy; Heart failure; Hydrogen Peroxide; Hydroxyl Radical; Investigation; Iron; Ischemia; Lead; Mediating; Mediator of activation protein; Methods; Mitochondria; Mitochondrial Proteins; Modification; Molecular; Mus; Myocardial Ischemia; NADPH Oxidase; Oxidases; Oxidation-Reduction; Oxidative Stress; Patients; Physiological; Physiology; Play; Post-Translational Protein Processing; Production; Protein Isoforms; Proteins; Proteomics; Reactive Oxygen Species; Regulation; Reperfusion Injury; Reperfusion Therapy; Role; Signaling Molecule; Source; Stimulus; Stress; Sulfur; Superoxides; Testing; Thioredoxin; Transgenic Organisms; Up-Regulation; age related; heart function; loss of function; mitochondrial dysfunction; mouse model; novel strategies; oxidation; pressure; prevent; protein function; public health relevance; research study; response; transcription factor

DESCRIPTION (provided by applicant): Reduction/oxidation (redox) is an important mechanism of post-translational modification controlling a wide variety of cellular functions. Reactive oxygen species (ROS) produced from various sources, such as mitochondrial leakage and NAD(P)H oxidases (Noxs), oxidize signaling molecules and transcription factors. Noxs are major enzymes responsible for production of superoxide (O2-), a component of ROS, at various subcellular localizations. O2- inactivates iron-sulfur cluster containing enzymes, thereby liberating free iron, which in turn generates the highly reactive hydroxyl radical. O2- produced in cells is rapidly converted to H2O2, while O2- also reacts with NO to form ONOO- , all of which act as ROS. Although the cellular function of plasma-membrane associated Noxs, such as Nox1 and p91phox (Nox2), has been extensively characterized, that of Nox4, an isoform of Nox expressed in the heart, is not well understood. Although oxidative stress in the heart is increased by aging and stress and during cardiac failure, the mechanism and localization of ROS production are not well understood. Our preliminary studies suggest that expression of Nox4 in the heart is upregulated by aging and pressure overload. However, the contribution of Nox4 to the increased oxidative stress and the progression of cardiac aging and heart failure remains to be elucidated. Furthermore, molecular mechanisms (targets) regulated by Nox4 and their contributions to growth and death responses in the heart are currently unknown. Interestingly, our preliminary results suggest that inhibition of Nox4 is protective during pressure overload but is detrimental during ischemia/reperfusion. The overall hypothesis in this proposal is that although physiological levels of Nox4 mediate cellular functions essential for cell survival under certain stress conditions, upregulation of Nox4 in aging and failing hearts elicits detrimental effects, such as increased production of ROS and subsequent mitochondrial dysfunction. In particular, our specific hypotheses are:1. Upregulation of Nox4 during aging and pressure overload increases oxidative stress, apoptosis and cardiac dysfunction, and is thereby detrimental. 2. Nox4 is a critical mediator of mitochondrial oxidative stress and mitochondrial dysfunction during heart failure. 3. The presence of a physiological level of Nox4 protects the heart from ischemia/reperfusion (I/R) injury. Nox4 plays an essential role in upregulating HIF-11 during acute ischemia, which in turn mediates stimulation of glycolysis, thereby preventing cardiac myocyte death during I/R. We will address these issues using newly generated mouse models of both gain and loss of function of Nox4, including Nox4 transgenic and KO mice, proteomic analyses and integrated physiology studies. Our results will elucidate the role of Nox4 in mediating both physiological and pathological functions in the heart during aging and under stresses. PUBLIC HEALTH RELEVANCE: Oxidation and reduction of proteins are important mechanisms regulating the function of proteins. During the past four years, we have been studying the function of thioredoxin 1, a small anti-oxidant, in the heart and demonstrated that thioredoxin1 is an essential regulator of protein oxidation/reduction in the heart and that thioredoxin1 negatively regulates cardiac hypertrophy by modifying cysteine residues of signaling molecules subjected to oxidation by hypertrophic stimuli. In this competing renewal, we will extend these observations and further elucidate the cellular functions modulated by oxidation and reduction of intracellular proteins in the heart. In particular, we will be focusing on NADPH oxidase 4 (Nox4), an enzyme producing superoxide, major reactive oxygen species in cells. Our preliminary results suggest that Nox4 is upregulated by aging and stress and mediates both physiological and pathological functions in the heart. Using newly generated genetically altered mouse models, together with the state of the art mouse physiology experiments, proteomic methods and NMR experiments, we will investigate the cardiac function of Nox4 and elucidate the molecular mechanisms by which Nox4 mediates both physiological and pathological functions in the heart. Our study will allow us to elucidate how the modification of cardiac proteins by oxidation and reduction affects physiological and pathological functions of the heart. The result obtained from this investigation may lead to development of a novel strategy to treat aging related heart diseases or congestive heart failure in patients by targeting oxidative modifications of specific cardiac proteins.

描述（由申请人提供）：还原/氧化（氧化还原）是控制多种细胞功能的翻译后修饰的重要机制。各种来源产生的活性氧 (ROS)，例如线粒体渗漏和 NAD(P)H 氧化酶 (Noxs)，会氧化信号分子和转录因子。 Nox 是负责在各种亚细胞定位产生超氧化物 (O2-) 的主要酶，超氧化物 (O2-) 是 ROS 的组成部分。 O2- 使含有铁硫簇的酶失活，从而释放游离铁，进而产生高反应性羟基自由基。细胞中产生的O2-迅速转化为H2O2，同时O2-也与NO反应形成ONOO-，所有这些都充当ROS。尽管质膜相关 Nox（例如 Nox1 和 p91phox (Nox2)）的细胞功能已得到广泛表征，但 Nox4（心脏中表达的 Nox 亚型）的细胞功能尚不清楚。尽管心脏的氧化应激会因衰老、压力和心力衰竭而增加，但 ROS 产生的机制和定位尚不清楚。我们的初步研究表明，衰老和压力超负荷会导致心脏中 Nox4 的表达上调。然而，Nox4 对氧化应激增加以及心脏衰老和心力衰竭进展的贡献仍有待阐明。此外，Nox4 调节的分子机制（靶标）及其对心脏生长和死亡反应的贡献目前尚不清楚。有趣的是，我们的初步结果表明，抑制 Nox4 在压力超负荷期间具有保护作用，但在缺血/再灌注期间是有害的。该提议的总体假设是，尽管 Nox4 的生理水平介导细胞在某些应激条件下生存所必需的功能，但在衰老和衰竭的心脏中 Nox4 的上调会引起有害影响，例如 ROS 产生增加和随后的线粒体功能障碍。具体来说，我们的具体假设是： 1．衰老和压力超负荷期间 Nox4 的上调会增加氧化应激、细胞凋亡和心脏功能障碍，因此是有害的。 2. Nox4是心力衰竭期间线粒体氧化应激和线粒体功能障碍的关键介质。 3.生理水平的Nox4的存在可以保护心脏免受缺血/再灌注(I/R)损伤。 Nox4 在急性缺血期间上调 HIF-11 中发挥着重要作用，HIF-11 进而介导糖酵解刺激，从而防止 I/R 期间心肌细胞死亡。我们将使用新生成的 Nox4 功能获得和丧失的小鼠模型（包括 Nox4 转基因和 KO 小鼠）、蛋白质组分析和综合生理学研究来解决这些问题。我们的研究结果将阐明 Nox4 在衰老和压力下调节心脏生理和病理功能中的作用。 公共健康相关性：蛋白质的氧化和还原是调节蛋白质功能的重要机制。在过去的四年中，我们一直在研究硫氧还蛋白1（一种小型抗氧化剂）在心脏中的功能，并证明硫氧还蛋白1是心脏中蛋白质氧化/还原的重要调节剂，并且硫氧还蛋白1通过修饰受肥大刺激氧化的信号分子的半胱氨酸残基来负调节心脏肥大。在这一竞争性更新中，我们将扩展这些观察结果，并进一步阐明心脏中细胞内蛋白质氧化和还原调节的细胞功能。我们将特别关注 NADPH 氧化酶 4 (Nox4)，这是一种产生超氧化物（细胞中主要活性氧）的酶。我们的初步结果表明，Nox4 会因衰老和压力而上调，并介导心脏的生理和病理功能。利用新生成的基因改造小鼠模型，结合最先进的小鼠生理学实验、蛋白质组学方法和核磁共振实验，我们将研究Nox4的心脏功能，并阐明Nox4介导心脏生理和病理功能的分子机制。我们的研究将使我们能够阐明氧化和还原对心脏蛋白质的修饰如何影响心脏的生理和病理功能。这项研究获得的结果可能会导致开发一种新策略，通过针对特定心脏蛋白的氧化修饰来治疗与衰老相关的心脏病或充血性心力衰竭患者。