Nox4 and Cardiac Fibrosis

Nox4 与心脏纤维化

基本信息

批准号：
7558921
负责人：
DAN SORESCU
金额：
$ 38.75万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-02-01 至 2013-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7558921
关键词：
Acetylation Actins Admission activity Affect Angiotensin II Binding Cardiac Cardiac Myocytes Cardiovascular system Chronic Cicatrix Collagen Complex Congestive Heart Failure Cysteine Data Development Enzymes Extracellular Matrix FOXO3A gene Fibroblasts Fibronectins Fibrosis Free Radical Formation Guanosine Triphosphate Phosphohydrolases Heart Heart Hypertrophy Heart failure Homeobox Hospitalization Human Hypertension Hypertrophy In Vitro Inflammation Infusion procedures JUN gene Knock-out Laboratories Link Location Mediating Mediator of activation protein Molecular Weight Monomeric GTP-Binding Proteins Mothers Mus Myocardial Infarction Myocardium Nuclear Nuclear Translocation Oxidases Oxidation-Reduction Pathway interactions Patients Pattern Phenotype Phosphotransferases Platelet Factor 4 Play Process Production Protein Isoforms Protein Tyrosine Phosphatase Proteins Publishing Reactive Oxygen Species Renin Role Source Testing Transforming Growth Factors Up-Regulation angiogenesis base connective tissue growth factor cytokine heart cell in vivo inhibitor/antagonist novel overexpression pressure prevent protein expression response rho transcription factor

项目摘要

DESCRIPTION (provided by applicant): NAD(P)H oxidases (Nox) are major sources of ROS in cardiac fibroblasts by reversibly oxidizing the cysteine residues in target proteins. We recently published that deletion of the isoform Nox4 in murine cardiac fibroblasts prevent Angiotensin II and TGF-1-induced cardiac fibrosis in vitro. The intimate mechanisms by which Nox4-released ROS mediate the pro-fibrotic transcriptional response to Ang II and TGF-1 are unknown. In this proposal we present additional data which supports that 1) Nox4 mediates TGF-1 and Ang II upregulation of fibrosis markers (SM- actin, collagen I, fibronectin, and CTGF) by controlling activation of transcription factors Smad2/3; 2) Nox4 binds to and regulates the small GTPase RhoA which in turns controls activation and nuclear translocation of transcription factors Smad2/3; 3) the novel redox-sensitive transcription factor FoxO3A is required for TGF-1 and Ang II expression of pro-fibrotic proteins and finally 4) Nox4 regulates de-acetylation of FoxO3A which is required for its proper function. Deletion of Nox4, Foxo3A, Smad2/3 prevent expression of SM- actin and Smad2/3 form a transcriptional complex with FoxO3A. Our central hypothesis is that Nox4-released ROS are essential for Ang II and TGF-1-induced fibrosis by inhibiting the tyrosine-phosphatase Shp2 that negatively regulates the activation and nuclear cooperation of transcription factors Smad2/3 and FoxO3A. The following specific aims will be accomplished: Aim 1. Establish the mechanism by which Nox4 controls activation of RhoA-Smad2/3 pathway and fibrotic proteins expression in response to Ang II and TGF-1 in murine cardiac fibroblasts. We will test whether Nox4 inhibits Shp2 and stimulates RhoA activation, required for Smad2/3 activation and nuclear translocation. Aim 2. Determine the specific mechanism by which Nox4 modulates FOXO3A- dependent SM- actin induction in response to Ang II and TGF-1. We plan to test that Nox4 regulates the transcriptional activity of Foxo3A by regulating activation of the redox-sensitive c-Jun-N-kinase (JNK) via inhibition of Shp2 and this is essential for induction of pro-fibrotic phenotype in response to Ang II and TGF-1. Aim 3. Establish the role of Nox4-based oxidase in cardiac fibrosis and hypertrophy in response to Ang II in mice in which Nox4 is over-expressed or deleted. We will test whether Nox4 is essential in vivo in Ang II-induced cardiac fibrosis by using Nox4 knockout or Nox4 overexpressing mice. Congestive heart failure is a major cause of hospitalization (over 500,000 admissions per year) and affects over 5 million patients in US. In the current application we will study the mechanism of development and progression of heart failure. Heart failure has two major causes: one is due to weakness of heart muscle caused by prior heart attacks or high blood pressure in which the heart muscle is replaced with scar and the other due to inappropriate accumulation of scar in the heart muscle which creates heart stiffness and increased pressures inside the heart. In our proposal we plan to identify the mechanisms by which the excessive scar forms as a consequence of increased free radicals formation in the heart. We have currently identified a key enzyme called Nox4, which is present in heart cells and is required for scar formation during the development of heart failure.

描述（由申请人提供）：NAD(P)H 氧化酶 (Nox) 通过可逆地氧化靶蛋白中的半胱氨酸残基，是心脏成纤维细胞中 ROS 的主要来源。我们最近发表了小鼠心脏成纤维细胞中异构体 Nox4 的缺失可在体外预防血管紧张素 II 和 TGF-1 诱导的心脏纤维化。 Nox4 释放的 ROS 介导对 Ang II 和 TGF-1 的促纤维化转录反应的密切机制尚不清楚。在本提案中，我们提供了额外的数据，支持以下观点：1) Nox4 通过控制转录因子 Smad2/3 的激活，介导 TGF-1 和 Ang II 上调纤维化标记物（SM-肌动蛋白、胶原蛋白 I、纤连蛋白和 CTGF）； 2) Nox4 结合并调节小 GTPase RhoA，进而控制转录因子 Smad2/3 的激活和核转位； 3) 新型氧化还原敏感转录因子 FoxO3A 是促纤维化蛋白的 TGF-1 和 Ang II 表达所必需的，最后 4) Nox4 调节 FoxO3A 的去乙酰化，这是其正常功能所必需的。 Nox4、Foxo3A、Smad2/3 的缺失会阻止 SM-肌动蛋白的表达，并且 Smad2/3 会与 FoxO3A 形成转录复合物。我们的中心假设是，Nox4 释放的 ROS 通过抑制酪氨酸磷酸酶 Shp2，对 Ang II 和 TGF-1 诱导的纤维化至关重要，而酪氨酸磷酸酶 Shp2 负向调节转录因子 Smad2/3 和 FoxO3A 的激活和核合作。将实现以下具体目标：目的 1. 建立 Nox4 控制小鼠心脏成纤维细胞中 RhoA-Smad2/3 通路激活和纤维化蛋白表达（响应 Ang II 和 TGF-1）的机制。我们将测试Nox4是否抑制Shp2并刺激RhoA激活，这是Smad2/3激活和核转位所必需的。目标 2. 确定 Nox4 响应 Ang II 和 TGF-1 调节 FOXO3A 依赖性 SM 肌动蛋白诱导的具体机制。我们计划测试Nox4通过抑制Shp2来调节氧化还原敏感的c-Jun-N-激酶（JNK）的激活来调节Foxo3A的转录活性，这对于诱导响应Ang II的促纤维化表型至关重要和TGF-1。目标 3. 在 Nox4 过度表达或缺失的小鼠中，确定基于 Nox4 的氧化酶在响应 Ang II 的心脏纤维化和肥大中的作用。我们将通过使用 Nox4 敲除或 Nox4 过表达小鼠来测试 Nox4 是否在体内 Ang II 诱导的心脏纤维化中至关重要。充血性心力衰竭是导致住院的主要原因（每年住院人数超过 500,000 人），影响美国超过 500 万患者。在当前的应用中，我们将研究心力衰竭发生和进展的机制。心力衰竭有两个主要原因：一是由于既往心脏病发作或高血压导致心肌无力，导致心肌被疤痕替代；二是由于疤痕在心肌中不适当的积累，导致心脏僵硬。以及心脏内的压力增加。在我们的提案中，我们计划确定由于心脏中自由基形成增加而导致过度疤痕形成的机制。我们目前已经鉴定出一种名为 Nox4 的关键酶，它存在于心脏细胞中，是心力衰竭发展过程中疤痕形成所必需的。