Nox4 and Cardiac Fibrosis

Nox4 与心脏纤维化

• 批准号: 7760158
• 负责人: DAN SORESCU
• 金额: $ 38.75万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 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/7760158
• 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

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）是心脏成纤维细胞中ROS的主要来源，通过将靶蛋白中的半胱氨酸残基可逆地氧化。我们最近发表了说，在鼠心脏成纤维细胞中的同工型NOX4的删除可预防血管紧张素II和TGF-1诱导的心脏纤维化体外。 NOX4释放的ROS介导对ANG II和TGF-1的促纤维转录反应的亲密机制尚不清楚。在此提案中，我们提供了其他数据，该数据支持1）NOX4通过控制转录因子SMAD2/3的激活来介导纤维化标记物（SM肌动蛋白，胶原I，纤连蛋白和CTGF）的TGF-1和ANG II上调； 2）NOX4与小的GTPase RhoA结合并调节，后者依次控制转录因子Smad2/3的激活和核转运； 3）新型氧化还原敏感的转录因子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的删除阻止Sm肌动蛋白的表达和Smad2/3与FoxO3A形成转录复合物。我们的中心假设是，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，该酪氨酸 - 磷酸酶SHP2对转录因子Smad2/3和FoxO3A的激活和核合作负面调节。将实现以下特定目的：目标1。建立NOX4控制RhoA-SMAD2/3途径的激活的机制，并响应于鼠心脏成纤维细胞中ANG II和TGF-1的纤维化蛋白表达。我们将测试NOX4是否抑制SHP2并刺激SMAD2/3激活和核易位所需的RhoA激活。 AIM 2。确定NOX4通过响应ANG II和TGF-1调节依赖FoxO3A的Sm肌动蛋白诱导的特定机制。我们计划测试NOX4通过调节氧化还原敏感的C-JUN-N-激酶（JNK）通过抑制SHP2的激活来调节FOXO3A的转录活性，这对于响应ANG II和TGF-1的响应促纤维性表型至关重要。 AIM 3。在NOX4被过表达或删除的小鼠中，确定基于NOX4的氧化酶在心脏纤维化和肥大中的作用。我们将通过使用NOX4基因敲除或NOX4过表达小鼠来测试NOX4在ANG II诱导的心脏纤维化中是否必不可少。充血性心力衰竭是住院的主要原因（每年超过500,000次入院），在美国影响超过500万患者。在当前的应用中，我们将研究心力衰竭发展和进展的机理。心力衰竭有两个主要原因：一种是由于先前的心脏病发作或高血压引起的心肌弱点，其中心肌被疤痕取代，另一个是由于心脏肌肉中不适当的疤痕积累而导致心脏僵硬并增加心脏内部的压力。在我们的提案中，我们计划确定由于心脏中自由基的增加而导致过度疤痕形成的机制。我们目前已经确定了一种称为NOX4的关键酶，该酶存在于心脏细胞中，并且在心力衰竭发展过程中是疤痕形成所必需的。