Hypoxia-mediated protective estrogen receptor signaling in pulmonary hypertension

肺动脉高压中缺氧介导的保护性雌激素受体信号传导

• 批准号: 8974320
• 负责人: Tim Lahm
• 金额: --
• 依托单位: RLR VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8974320
• 关键词: Acute; Affect; Apoptosis; Attenuated; Autophagocytosis; Biochemical; Biogenesis; Biological; Blood Vessels; Cardiopulmonary; Cell Hypoxia; Cell Proliferation; Cell Wall; Chemicals; Chronic lung disease; Clinical; Complement; Data; Development; Disease; Echocardiography; Endothelium; Estradiol; Estrogen Receptors; Estrogens; Event; Exhibits; Failure; Female; Genetic Transcription; Goals; Health; Hypertrophy; Hypoxia; Hypoxia Inducible Factor; In Vitro; Investigation; Ischemia; KDR gene; Knock-out; Longevity; Lung; MAP Kinase Gene; MAPK3 gene; Measurement; Mediating; Mission; Mitochondria; Modeling; Molecular; Molecular Target; Muscle Cells; Pathway interactions; Patients; Pattern; Pulmonary Hypertension; Pulmonary artery structure; Rattus; Receptor Signaling; Research; Right ventricular structure; Rodent Model; Signal Transduction; Time; Tissues; Transgenic Mice; Transgenic Organisms; Vascular Proliferation; Vasodilation; Ventricular; Ventricular Remodeling; Veterans; Woman; Work; base; cardiopulmonary system; clinically relevant; exercise capacity; hemodynamics; hormone therapy; hypoxia inducible factor 1; improved; improved functioning; in vivo; insight; male; mitochondrial autophagy; mouse model; novel; overexpression; primary pulmonary hypertension; programs; protective effect; pulmonary artery endothelial cell; receptor expression; research study; response; simulation; therapeutic target; treatment strategy; vasoconstriction

DESCRIPTION (provided by applicant): Hypoxia-induced pulmonary hypertension (HPH) is a serious clinical problem in veterans with chronic lung disease. 17beta-estradiol (E2) attenuates HPH, but the mechanisms are poorly understood. Our preliminary data demonstrate that 1) E2's anti-proliferative effects occur exclusively during actual or chemical hypoxia and 2) hypoxia upregulates estrogen receptor (ER) transcription and/or expression in pulmonary artery endothelial cells (PAECs) and the right ventricle (RV). We hypothesize that the mechanism through which E2 attenuates PH development and improves RV function is through hypoxia- and hypoxia-inducible factor (HIF) 1alpha- enabled increases in ER expression in the PA-RV unit, with subsequent induction of cellular autophagy and improved RV mitochondrial biogenesis. Since RV failure in both HPH as well as non-hypoxic forms of PH is characterized by global or local (cellular) hypoxia with activation of known HIF-1alpha inducers, we propose that the RV-protective effects of the E2-ER-axis against hypoxia-induced (adaptive) RV remodeling will extend to RV failure characterized by maladaptive remodeling. Our mechanistic experimental approach utilizes comprehensive clinically relevant PH endpoints in vivo, complemented by studies in primary PAECs. We propose the following specific aims: SA#1: To determine if enhancing ER signaling protects against development of PH. 1a: To establish the pattern and time course of hypoxia- and HIF1¿-induced increases in ER expression in the pulmonary vasculature and RV. 1b: To investigate if transgenic conditional tissue-specific enhancement of ER signaling potentiates E2's protective effects in HPH and even in non-hypoxic forms of PH. 1c: To interrogate whether enhancing ER signaling is sufficient to protect against HPH or non-hypoxic PH even in the absence of further stimulation by exogenous E2 SA#2: To establish the mechanisms by which E2 inhibits RV remodeling and improves RV function during both adaptive and maladaptive RV responses in PH. 2a: To elucidate if E2 protects against pathological RV remodeling by a mechanism involving ER¿-dependent autophagy in both adaptive and maladaptive RV hypertrophy models. 2b: To investigate if E2 improves RV function by optimizing mitochondrial substrate utilization during both adaptive and maladaptive RV responses in PH. In vivo experiments will be performed in two distinct rodent models of PH: a) HPH and b) VEGF-receptor blockade plus hypoxia-induced PH. We will primarily employ transgenic mouse models for mechanistic experiments, and use rats for studies requiring comprehensive analysis of functional endpoints. Endpoints assessed in vivo include hemodynamics, RV form/function by echocardiography, exercise capacity, and PA/RV remodeling, complemented by in vivo and in vitro measurements of ER expression, cellular proliferation, survival, apoptosis and autophagy, as well as HIF-1alpha activation and mitochondrial substrate utilization. The proposed studies are novel because they will 1) for the first time establish the mechanisms of ER protection in the cardiopulmonary system; 2) be the first investigations to extend the protective effects of E2 to more severe forms of RV failure; and 3) substantiate the novel appreciation of the key role of autophagy and mitochondrial substrate utilization in ER-mediated protection in the failing RV. The studies proposed are significant because 1) the results will facilitate the identification of nw therapeutic targets directed at advanced forms of RV failure; 2) the work will be a critical step towards our long-term goal of developing targeted non-hormonal therapies to benefit male and female veterans with PH; and 3) the results may explain why women are more prone to idiopathic pulmonary arterial hypertension development, yet - once affected - exhibit less severe disease.

描述（由申请人提供）： 低氧诱导的肺动脉高压（HPH）是退伍军人慢性肺部疾病的严重临床问题。17 β-雌二醇（E2）可减轻HPH，但其机制尚不清楚。我们的初步数据表明，1）E2的抗增殖作用只发生在实际或化学缺氧和2）缺氧上调雌激素受体（ER）的转录和/或表达在肺动脉内皮细胞（PAEC）和右心室（RV）。我们假设E2减弱PH发展和改善RV功能的机制是通过缺氧和缺氧诱导因子（HIF）1 α激活的PA-RV单位ER表达增加，随后诱导细胞自噬和改善RV线粒体生物合成。由于HPH和非缺氧型PH的RV衰竭的特征是全身或局部（细胞）缺氧，并激活已知的HIF-1 α诱导剂，我们认为E2-ER轴对缺氧诱导的（适应性）RV重构的RV保护作用将扩展到以适应不良重构为特征的RV衰竭。我们的机械实验方法利用了体内全面的临床相关PH终点，并辅以原发性PAEC研究。我们提出了以下具体目标：SA #1：确定增强ER信号传导是否可以防止PH的发展。1a：建立缺氧和HIF 1？诱导的肺血管和RV中ER表达增加的模式和时间过程。1b：研究ER信号的转基因条件性组织特异性增强是否增强了E2在HPH中甚至在非缺氧形式的PH中的保护作用。1c：为了询问增强ER信号是否足以保护免受HPH或非缺氧PH，即使在不存在外源性E2SA#2的进一步刺激的情况下：建立E2在PH 2a适应性和适应不良RV反应期间抑制RV重塑和改善RV功能的机制。阐明E2是否通过涉及ER的机制防止病理性RV重塑。适应性和适应不良RV肥大模型中的-依赖性自噬。2b：为了研究E2是否通过优化PH适应性和适应不良RV反应期间线粒体底物利用率来改善RV功能。将在两种不同的PH啮齿动物模型中进行体内实验：a）HPH和B）VEGF受体阻断加缺氧诱导的PH。我们将主要采用转基因小鼠模型进行机制实验，并使用大鼠进行需要全面分析功能终点的研究。体内评估的终点包括血流动力学、超声心动图检查的RV形式/功能、运动能力和PA/RV重塑，并辅以ER表达、细胞增殖、存活、凋亡和自噬以及HIF-1 α活化和线粒体底物利用的体内和体外测量。拟议的研究是新颖的，因为它们将：1）首次建立心肺系统中ER保护的机制; 2）首次研究将E2的保护作用扩展到更严重形式的RV衰竭; 3）证实了对自噬和线粒体底物利用在失败RV中ER介导的保护中的关键作用的新认识。提出的研究是重要的，因为1）结果将有助于识别针对晚期RV衰竭的新治疗靶点; 2）这项工作将是朝着我们开发靶向非激素疗法的长期目标迈出的关键一步，以使患有PH的男性和女性退伍军人受益;以及3）该结果可以解释为什么女性更容易发生特发性肺动脉高压，但一旦受到影响，疾病的严重程度较低。