PPAR gamma and Nox4 in pulmonary hypertension

PPAR γ 和 Nox4 在肺动脉高压中的作用

基本信息

批准号：
8963181
负责人：
C MICHAEL HART
金额：
$ 30.92万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-01-01 至 2019-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8963181
关键词：
Accounting Attenuated Biogenesis Biological Assay Blood Vessels Cell Count Cell Proliferation Cells Clinical Complex Confocal Microscopy Critical Pathways Data Disease Echocardiography Fluorescence Functional disorder Funding Generations Genetic Genus Hippocampus Glycolysis Health Hormones Human Hydrogen Peroxide Hypoxia Immunohistochemistry In Vitro Knockout Mice Ligands Link Lung Measures Membrane Potentials Metabolic Mitochondria Mitogen-Activated Protein Kinase 3 Modeling Morbidity - disease rate Mus NADPH Oxidase Nuclear Nuclear Antigens Oleic Acids Oxygen Consumption PPAR gamma Pathogenesis Pathology Pathway interactions Patients Phenotype Play Predisposition Production Proliferating Proteins Pulmonary Hypertension Pulmonary Vascular Resistance Pulmonary artery structure Reactive Oxygen Species Research Research Personnel Right Ventricular Hypertrophy Role Small Interfering RNA Smooth Muscle Smooth Muscle Actin Staining Method Smooth Muscle Myocytes Staining method Stains Stimulus Systolic Pressure Techniques Testing UCP2 protein Vascular remodeling Vasodilation Ventricular Ventricular Function arteriole catalase gain of function in vivo in vivo Model insight loss of function mitochondrial dysfunction mitochondrial membrane morphometry mortality new therapeutic target novel novel strategies overexpression pulmonary arterial hypertension receptor response skills transcription factor

项目摘要

DESCRIPTION (provided by applicant): Pulmonary hypertension (PH) is a complex disorder that causes significant morbidity and mortality. Mounting evidence suggests that metabolic derangements account for the pathophysiology underlying PH. This proposal focuses peroxisome proliferator-activated receptor gamma (PPARγ), a major metabolic regulator that is decreased PH. Hypoxia and other causes of PH decrease PPARγ expression which increases NADPH oxidase 4 (Nox4) expression and activity. Nox4 generates reactive oxygen species (ROS) that contribute to pulmonary vascular cell proliferation and PH pathogenesis. On the other hand, stimulating PPARγ reduces the expression and activity of Nox4 and attenuates hypoxia-induced vascular remodeling, right ventricular hypertrophy, and PH. The mechanisms by which PPARγ modulates PH continue to be defined. Preliminary data suggest that reductions in PPARγ reduce the expression of PPARγ coactivator 1 alpha (PGC1α) and uncoupling protein 2 (UCP2), proteins that regulate mitochondrial (MT) biogenesis and reactive oxygen species (ROS) generation, respectively. The proposed studies will test the hypothesis that PPARγ depletion reduces pulmonary artery smooth muscle cell (PASMC) PGC1α and UCP2 and stimulates MT dysfunction and ROS production. The investigators further postulate that MT ROS activate the ERK 1/2-NF-κB axis to increase Nox4 expression and H2O2 generation which promote PASMC proliferation, pulmonary vascular remodeling, and PH. To test this hypothesis, Specific Aim 1 will explore the role of reduced PPARγ activity in MT dysfunction, Nox4 induction, and PASMC proliferation using complementary in vitro and in vivo models. Genetic or pharmacological reductions in PPARγ activity will be used in human PASMC in vitro, and inducible, smooth muscle-targeted PPARγ knockout mice (smPPARγKO) will be employed in vivo. Specific Aim 2 will examine the role of reductions in PPARγ in hypoxia-induced alterations in PGC1α and UCP2, MT dysfunction, Nox4 induction, and PASMC proliferation. In vitro and in vivo gain and loss of PPARγ function models will be exposed to well characterized control or hypoxic conditions, and MT function, ROS production, and PASMC proliferation will be determined. Hypoxia-induced PH will be assessed with measures of right ventricular systolic pressure, right ventricular hypertrophy, and ventricular function (echocardiography). PASMC proliferation will be examined with immunohistochemistry for proliferating cellular nuclear antigen and morphometric analysis of lung sections stained for α-smooth muscle actin. The ability of full and partial (10- nitro-oleic acid) PPARγ ligands to attenuate hypoxic proliferatin and PH will be tested. Critical observations will be confirmed in PASMC isolated from patients with idiopathic pulmonary arterial hypertension. The proposed studies, conducted by a productive and collaborative research team, will advance understanding of the role of PPARγ in regulating PASMC phenotype during health and disease and identify novel strategies by which targeting PPARγ can interrupt PH pathogenesis.

描述（由应用提供）：肺动脉高压（pH）是一种复杂的疾病，会引起明显的发病率和死亡率。越来越多的证据表明，代谢进化解释了pH的病理生理学。该提案聚焦了过氧化物组增殖物激活的受体伽马（PPARγ），这是一种主要的代谢调节剂，降低了pH。缺氧和其他pH值的原因降低了PPARγ表达，从而增加了NADPH氧化物4（NOX4）的表达和活性。 NOX4产生活性氧（ROS），有助于肺血管细胞增殖和pH发病机理。另一方面，刺激PPARγ降低了NOX4的表达和活性，并减少缺氧诱导的血管重塑，右心室肥大和pH。 PPARγ调节pH的机制继续定义。初步数据表明，PPARγ的降低降低了PPARγ共激活因子1α（PGC1α）和解偶联蛋白2（UCP2）的表达，分别调节线粒体（MT）生物发生和活性氧（ROS）的蛋白质（UCP2）分别产生。拟议的研究将检验以下假设：PPARγ耗竭减少肺动脉平滑肌细胞（PASMC）PGC1α和UCP2并刺激MT功能障碍和ROS产生。研究人员进一步假设MT ROS激活ERK 1/2-NF-κB轴以增加NOX4表达和H2O2的产生，从而促进PASMC增殖，肺血管重塑和pH。为了检验这一假设，具体目标1将探讨降低PPARγ活性在MT功能障碍，NOX4诱导，使用完整的体外和体内模型的PASMC增殖。 PPARγ活性的遗传学或药理降低将在人类的PASMC体外使用，并在体内进行诱导的，平滑的肌肉靶向PPARγ基因敲除小鼠（SMPPARγKO）。具体目标2将检查PPARγ降低在缺氧诱导的PGC1α和UCP2，MT功能障碍，NOX4诱导和PASMC增殖中的变化中的作用。体外和体内增益和PPARγ功能模型的丧失将暴露于表征良好的控制或低氧条件下，并确定MT功能，ROS产生和PASMC增殖。缺氧引起的pH值将通过测量右心室收缩压，右心肥大和心室功能（超声心动图）进行评估。 PASMC增殖将通过免疫组织化学检查，用于对细胞核抗原的增殖和对α-平滑肌肌动蛋白染色的肺切片的形态分析。将测试全部和部分（10-硝基酸）PPARγ配体减弱低氧增殖和pH的能力。从特发性肺动脉高压患者中分离出的PASMC中，将确认关键观察结果。由生产性和协作研究团队进行的拟议研究将促进对PPARγ在健康和疾病中调节PASMC表型中的作用的理解，并确定针对PPARγ可以中断PH pH发病机理的新型策略。