PPAR gamma and Nox4 in pulmonary hypertension

PPAR γ 和 Nox4 在肺动脉高压中的作用

• 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
• 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

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（由申请人提供）：肺动脉高压（PH）是一种复杂的疾病，可导致显著的发病率和死亡率。越来越多的证据表明，代谢紊乱解释PH的病理生理基础。该建议关注过氧化物酶体增殖物激活受体γ（PPARγ），一种主要的代谢调节剂，降低PH。缺氧和PH的其他原因降低PPARγ表达，增加NADPH氧化酶4（Nox 4）的表达和活性。Nox 4产生活性氧（ROS），促进肺血管细胞增殖和PH发病机制。另一方面，刺激PPARγ可降低Nox 4的表达和活性，减轻缺氧诱导的血管重构、右心室肥大和PH。初步数据表明，PPARγ的减少降低了PPARγ共激活因子1 α（PGC 1 α）和解偶联蛋白2（UCP 2）的表达，这两种蛋白分别调节线粒体（MT）生物合成和活性氧（ROS）的产生。拟开展的研究将检验以下假设：PPARγ耗竭减少肺动脉平滑肌细胞（PASMC）PGC 1 α和UCP 2，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Nox 4表达和H2 O2产生，从而促进PASMC增殖、肺血管重塑和PH。为了验证这一假设，特异性目的1将探索降低的PPARγ活性在MT功能障碍、Nox 4诱导、 和PASMC增殖使用互补的体外和体内模型。将在体外人PASMC中使用PPARγ活性的遗传或药理学降低，并将在体内使用可诱导的平滑肌靶向PPARγ敲除小鼠（smPPARγKO）。具体目标2将检查PPARγ减少在PGC 1 α和UCP 2、MT功能障碍、Nox 4诱导和PASMC增殖的缺氧诱导变化中的作用。将体外和体内获得和丧失PPARγ功能的模型暴露于充分表征的对照或缺氧条件，并测定MT功能、ROS产生和PASMC增殖。将通过测量右心室收缩压、右心室肥大和心室功能（超声心动图）评估缺氧诱导的PH。将通过增殖细胞核抗原的免疫组织化学和α-平滑肌肌动蛋白染色的肺切片的形态计量学分析来检查PASMC增殖。将测试全部和部分（10-硝基-油酸）PPARγ配体减弱缺氧增殖和PH的能力。将在从特发性肺动脉高压患者中分离的PASMC中证实关键观察结果。由一个富有成效的合作研究团队进行的拟议研究将促进对PPARγ在健康和疾病期间调节PASMC表型的作用的理解，并确定靶向PPARγ可以中断PH发病机制的新策略。