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，会导致显着的发病率和死亡率。越来越多的证据表明，代谢紊乱是 PH 的病理生理学基础。该提案重点关注过氧化物酶体增殖物激活受体 γ (PPARγ)，它是一种降低 PH 的主要代谢调节剂。缺氧和其他 PH 原因会降低 PPARγ 表达，从而增加 NADPH 氧化酶 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 发病机制。另一方面，刺激 PPARγ 会降低 Nox4 的表达和活性，并减弱缺氧诱导的血管重塑、右心室肥厚和 PH。 PPARγ 调节 PH 的机制仍在不断明确。初步数据表明，PPARγ 的减少会降低 PPARγ 辅激活因子 1 α (PGC1α) 和解偶联蛋白 2 (UCP2) 的表达，这两种蛋白质分别调节线粒体 (MT) 生物合成和活性氧 (ROS) 生成。拟议的研究将检验以下假设：PPARγ 耗竭会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。研究人员进一步推测，MT ROS 激活 ERK 1/2-NF-κB 轴，增加 Nox4 表达和 H2O2 生成，从而促进 PASMC 增殖、肺血管重塑和 PH。为了检验这一假设，Specific Aim 1 将探讨 PPARγ 活性降低在 MT 功能障碍、Nox4 诱导、 使用互补的体外和体内模型进行 PASMC 增殖。 PPARγ 活性的遗传或药理学降低将用于体外人 PASMC，而可诱导的、平滑肌靶向的 PPARγ 敲除小鼠 (smPPARγKO) 将用于体内。具体目标 2 将检查 PPARγ 减少在缺氧诱导的 PGC1α 和 UCP2 改变、MT 功能障碍、Nox4 诱导和 PASMC 增殖中的作用。 PPARγ 功能的体外和体内获得和丧失模型将暴露于充分表征的对照或缺氧条件下，并确定 MT 功能、ROS 产生和 PASMC 增殖。通过测量右心室收缩压、右心室肥厚和心室功能（超声心动图）来评估缺氧引起的 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。关键观察结果将在从特发性肺动脉高压患者分离的 PASMC 中得到证实。拟议的研究由一个富有成效的协作研究团队进行，将加深对 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 中断 PH 发病机制的新策略。