mTOR coordinates cell metabolism, growth and survival in pulmonary hypertension

mTOR 协调肺动脉高压中的细胞代谢、生长和存活

• 批准号: 8398297
• 负责人: Elena Goncharova
• 金额: $ 40万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8398297
• 关键词: Apoptosis; Blood Vessels; Cell Proliferation; Cell Respiration; Cell Survival; Cells; Cessation of life; Chronic; Complex; Data; Disease; Dominant-Negative Mutation; Echocardiography; Functional disorder; Generations; Glycolysis; Growth; Health; Heart failure; Human; Hypoxia; In Vitro; Link; Lung; Measurement; Metabolic; Metabolism; Modeling; Molecular; Molecular Abnormality; Molecular Target; Mus; PTEN gene; Pathogenesis; Patients; Phosphotransferases; Protein Biosynthesis; Protein Kinase; Proteins; Publishing; Pulmonary Hypertension; Pulmonary artery structure; Raptors; Rattus; Reporting; Resistance; Role; Signal Pathway; Signal Transduction; Sirolimus; Smooth Muscle; Smooth Muscle Myocytes; Structure of parenchyma of lung; TSC1/2 gene; Testing; Tissue Sample; Translations; Tumor Suppressor Proteins; Vascular remodeling; Ventricular; base; cell growth; hemodynamics; hypoxia inducible factor 1; in vivo; inhibitor/antagonist; insight; kinase inhibitor; knock-down; mTOR protein; member; novel; prevent; pulmonary arterial hypertension; sensor; tool; vascular smooth muscle cell proliferation

DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH), a progressive fatal disease, manifests by vascular remodeling of pulmonary arteries (PA), elevated right ventricular afterload, right heart failure and death. Enhanced proliferation and impaired apoptosis of pulmonary arterial vascular smooth muscle cells (PAVSMC) are key pathophysiological components of vascular remodeling in PAH, the molecular mechanisms of which are not fully understood. This proposal focuses on two functionally distinct complexes of mammalian target of rapamycin (mTOR), mTORC1 and mTORC2, as novel regulators of PAVSMC metabolism, growth and survival in PAH. By using PAVSMC from subjects with idiopathic PAH (human PAH PAVSMC) and unused donor lungs, we show that cultured human PAH PAVSMC retain molecular and cellular abnormalities reported in PAH lungs in vivo, such as elevated proliferation, survival, and altered cellular ATP levels due to glycolytic metabolism that provides a unique tool for translational mechanistic studies. Our published study demonstrates that increased PAVSMC proliferation under chronic hypoxia requires activation of both mTORC1 and mTORC2. Our preliminary data show that mTORC1 and mTORC2 signaling pathways are up-regulated in vivo and in vitro in PAVSMC from small PA from subjects with idiopathic PAH and from rats with chronic hypoxia-induced pulmonary vascular remodeling. Our data also show that both mTORC1 and mTORC2 promote proliferation, but only mTORC2 modulates cellular energy levels and cell survival and suggest that inhibition of both mTORC1 and mTORC2 is required to suppress growth, proliferation and promote apoptosis in human PAH PAVSMC. Based on published studies and our data, we hypothesize that increased proliferation and survival of PAVSMC in PAH requires activation of both mTORC1 (promoting protein synthesis and cell growth) and mTORC2 (activating Akt, increasing cellular energy levels, down-regulating AMPK and increasing cell survival). We also propose that targeting mTOR in both mTORC1 and mTORC2 is necessary to inhibit PAVSMC growth, proliferation, promote apoptosis, and prevent or abrogate pulmonary vascular remodeling in PAH. To test this hypothesis, in Aim 1, activation of mTORC1 and mTORC2 signaling pathways will be critically tested using lung tissue samples from PAH patients and healthy donors and cultured PAVSMC from idiopathic PAH patients and unused donor lungs; in Aim 2, we will determine whether mTORC1 and mTORC2 employ differential molecular mechanisms to modulate growth, proliferation and survival of human PAH PAVSMC. Specific roles of mTORC1 and mTORC2 in regulating cell growth, cellular ATP levels and apoptosis will be examined; in Aim 3, we will evaluate whether suppression of both mTORC1 and mTORC2 inhibits growth, cellular energy levels, proliferation and induces apoptosis in vitro in human PAH PAVSMC and prevents or abrogates pulmonary vascular remodeling in vivo in a rat chronic hypoxia model of PH. Proposed studies will define the role of mTOR in regulating energy levels, growth, proliferation and survival of PAH PAVSMC and will explore whether mTOR could serve as a potential molecular target for treatment of human PAH.

描述（由申请人提供）：肺动脉高压（PAH）是一种进行性致命疾病，表现为肺动脉（PA）血管重塑、右心室后负荷升高、右心衰竭和死亡。肺动脉血管平滑肌细胞（PAVSMC）增殖增强和凋亡受损是PAH血管重塑的关键病理生理学组成部分，其分子机制尚不完全清楚。该提案重点关注哺乳动物雷帕霉素靶点 (mTOR) 的两种功能不同的复合物，mTORC1 和 mTORC2，作为 PAH 中 PAVSMC 代谢、生长和存活的新型调节剂。通过使用来自特发性 PAH 受试者（人 PAH PAVSMC）和未使用的供体肺的 PAVSMC，我们发现培养的人 PAH PAVSMC 保留了体内 PAH 肺中报告的分子和细胞异常，例如由于糖酵解代谢导致的增殖、存活和细胞 ATP 水平改变，这为转化机制研究提供了独特的工具。我们发表的研究表明，慢性缺氧条件下 PAVSMC 增殖增加需要 mTORC1 和 mTORC2 的激活。我们的初步数据表明，在特发性 PAH 受试者的小 PA 和慢性缺氧诱导的肺血管重塑大鼠的 PAVSMC 中，mTORC1 和 mTORC2 信号通路在体内和体外均上调。我们的数据还表明，mTORC1 和 mTORC2 均促进增殖，但只有 mTORC2 调节细胞能量水平和细胞存活，表明抑制 mTORC1 和 mTORC2 是抑制人 PAH PAVSMC 生长、增殖和促进细胞凋亡所必需的。根据已发表的研究和我们的数据，我们假设 PAH 中 PAVSMC 的增殖和存活增加需要激活 mTORC1（促进蛋白质合成和细胞生长）和 mTORC2（激活 Akt，增加细胞能量水平，下调 AMPK 并增加细胞存活）。我们还提出，靶向 mTORC1 和 mTORC2 中的 mTOR 对于抑制 PAVSMC 生长、增殖、促进细胞凋亡以及预防或消除 PAH 中的肺血管重塑是必要的。为了检验这一假设，在目标 1 中，将使用来自 PAH 患者和健康供体的肺组织样本以及来自特发性 PAH 患者和未使用的供体肺的培养 PAVSMC 严格测试 mTORC1 和 mTORC2 信号通路的激活；在目标 2 中，我们将确定 mTORC1 和 mTORC2 是否采用不同的分子机制来调节人 PAH PAVSMC 的生长、增殖和存活。将检查 mTORC1 和 mTORC2 在调节细胞生长、细胞 ATP 水平和细胞凋亡中的具体作用；在目标 3 中，我们将评估抑制 mTORC1 和 mTORC2 是否会在体外抑制人类 PAH PAVSMC 的生长、细胞能量水平、增殖并诱导细胞凋亡，并在体内预防或消除 PH 大鼠慢性缺氧模型中的肺血管重塑。拟议的研究将明确 mTOR 在调节 PAH PAVSMC 的能量水平、生长、增殖和存活中的作用，并将探讨 mTOR 是否可以作为治疗人类 PAH 的潜在分子靶点。