Mechanisms and Consequences of Reduced PPAR gamma in Pulmonary Hypertension

肺动脉高压中 PPAR γ 减少的机制和后果

• 批准号: 8598800
• 负责人: C MICHAEL HART
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8598800
• 关键词: Address; Adverse effects; Affect; Attenuated; Behavior; Binding; Blood Vessels; Cell Proliferation; Cell Wall; Chronic; Chronic Obstructive Airway Disease; Collagen; Complex; Complication; Congestive Heart Failure; Data; Development; Disease; Down-Regulation; Electrophoretic Mobility Shift Assay; Endothelin-1; Event; Exposure to; Gene Expression; HIV Infections; Healthcare; Human; Hypertension; Hypoxia; In Vitro; Interstitial Lung Diseases; Lead; Ligands; Lower respiratory tract structure; Luciferases; Lung; Measures; Mediator of activation protein; MicroRNAs; Modeling; Morbidity - disease rate; Mus; NADPH Oxidase; NF-kappa B; Names; Nuclear Hormone Receptors; Obstructive Sleep Apnea; Outcome; PPAR gamma; Pathogenesis; Pathway interactions; Patients; Peroxisome Proliferator-Activated Receptors; Pharmaceutical Preparations; Polymerase Chain Reaction; Post-Transcriptional Regulation; Prevention; Publishing; Pulmonary Heart Disease; Pulmonary Hypertension; Pulmonary artery structure; Pulmonary vessels; Receptor Activation; Relative (related person); Reporter; Research; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Pathway; Small Interfering RNA; Smooth Muscle Myocytes; Stimulus; Techniques; Therapeutic; Therapeutic Effect; Thrombospondin 1; Time; Untranslated Regions; Vascular Diseases; Vascular Endothelial Growth Factor Receptor; Vascular remodeling; Veterans; Western Blotting; dosage; effective therapy; endothelial dysfunction; hypertension treatment; improved; in vivo; mortality; novel; novel strategies; novel therapeutics; overexpression; patient population; peroxisome; prevent; programs; promoter; public health relevance; pulmonary arterial hypertension; receptor; vasoconstriction

DESCRIPTION (provided by applicant): Pulmonary hypertension (PH) is a devastating cardiopulmonary disorder with significant morbidity and mortality that frequently complicates disorders that affect the veteran patient population. Existing PH therapies are expensive and not optimally effective, indicating that novel approaches to PH treatment are urgently needed. This proposal seeks to define new pathways in PH pathogenesis and develop novel strategies for PH therapy. The proposed studies focus on the nuclear hormone receptor, peroxisome proliferator-activated receptor gamma (PPARg) which has been implicated in PH pathogenesis. Reduced PPARg expression caused PH whereas activation of PPARg with existing medications attenuated PH. Unfortunately, these same PPARg ligands also cause significant side effects. Thus to avoid these adverse effects, this proposal examines mechanisms of PPARg downregulation in PH and ways to prevent it as a new and alternative strategy in PH therapy. The investigators will examine PH in mice caused by exposure to chronic hypoxia ¿ treatment with a vascular endothelial growth factor receptor (VEGF-R) antagonist. Complementary studies will be performed in vitro in human pulmonary artery endothelial or smooth muscle cells (HPAEC or HPASMC) exposed to hypoxia or in HPAEC or HPASMC isolated from control or PH patients. The investigators hypothesize that hypoxia- induced reductions in PPARg in the pulmonary vascular wall promote the expression of downstream mediators that cause vascular cell proliferation, remodeling and PH. Further, it is predicted that preventing or attenuating reductions in PPARg expression and function will reduce proliferative mediator expression and PH. The proposal will address 2 specific aims. The first aim focuses on transcriptional mechanisms that regulate PPARg expression. Aim 1 will determine the role of NF-kB in suppressing PPARg promoter activity. Published and preliminary data demonstrate that NF-kB is activated in PH and by exposure to chronic hypoxia. The expression of PPARg and downstream PPARg-regulated proliferative mediators (including NADPH oxidase 4, endothelin-1, and thrombospondin-1) will be measured in the proposed models using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Vascular cell proliferation, vascular remodeling, and PH will be determined with techniques published by the investigative team. Activation of NF-kB will be determined by electrophoretic mobility shift assays. siRNA will be administered to inhibit NF-kB to determine its role in reduced PPARg expression and in the increased expression of proliferative mediators that cause PH. Aim 2 will focus on the post-transcriptional regulation of PPARg by microRNA-27 (miR-27). Levels of miR-27 will be measured in the models employed in Aim 1 using qRT-PCR, and its role in PH pathobiology will be established using miR-27 antagonists or overexpression. Binding of miR-27 to the PPARg 3'-UTR will be confirmed using luciferase reporter constructs. Intranasal delivery of anti-miR-27 to the lower respiratory tract will be used in vivo to determine if preventing increases in miR-27 can avert reductions in PPARg and attenuate downstream increases in proliferative mediators. The proposed studies will clarify pathogenic mechanisms in PH and define the relative contributions of transcriptional and post-transcriptional pathways to reductions in PPARg. The outcomes will determine if strategies to prevent reductions in pulmonary vascular PPARg expression can provide a novel approach to PH therapy. The proposed strategies might also enhance the therapeutic effects of existing PPARg ligands thereby permitting reductions in dosage and associated side effects. The results of this proposal can thereby define novel and effective therapeutic strategies to regulate programs of gene expression involved in PH pathogenesis.

描述（由申请人提供）： 肺动脉高压（pH）是一种毁灭性的，具有明显的病态和死亡率，会影响现有的pH疗法。核激素受体某些激活的受体γ（PPARG）与pH的发病机理有关以及防止其作为pH疗法的新策略的方法。用血管室内热生长因子受体（VEGF-R）拮抗剂的治疗。低氧诱导的肺血管壁的编辑促进了下游的表达，即停止血管细胞的繁殖，重塑和pH。调节PPARG SION的机制将确定NF-KB在抑制PPARG启动子活性中的作用。 -1）将在使用定量的实时聚合酶链反应（QRT-PCR）和Western印迹的支撑模型中进行测量。 shift sirna将被抑制pPARG的NF-KB表达，并在ppar的ppargers ppargs pparg上通过microRNA-27的pparg pparge（mir-27）。在AIM 1 QRT-PC中采用的模型中进行测量，将使用miR-27 Atagonist或Mir-27与PPARG 3'-UTR的结合来确定其在病理生物学中的作用。鼻内抗MIR-27向下呼吸道的递送将在体内使用 如果MiR-27的增加可以避免PPARG的减少，而下游会增加拟议中的介体。 ExpressSion可以提供一种新的pH疗法的方法，从而增强了偶然的配体的治疗方法，从而可以减少剂量和相关的副作用。