Estrogen receptor-alpha effects on right ventricular vascular density and angiogenesis in pulmonary hypertension

雌激素受体-α 对肺动脉高压右心室血管密度和血管生成的影响

• 批准号: 10523268
• 负责人: Tim Lahm
• 金额: --
• 依托单位: VA EASTERN COLORADO HEALTH CARE SYSTEM
• 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 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10523268
• 关键词: Estrogen; receptor; alpha; effects; right

Pulmonary hypertension (PH) and right ventricular (RV) dysfunction are extremely common in veterans. Up to 80% of veterans with chronic obstructive pulmonary disease, pulmonary fibrosis, sleep disordered breathing or LV dysfunction (either systolic or diastolic) suffer from PH. Better RV function and female sex have been linked to improved survival in PH, and female patients exhibit better RV function than their male counterparts. This proposal builds on the scientific premise that even though RV function and female sex are major determinants of survival in PH, no RV-specific or sex steroid-directed therapies exist. Endothelial cell (EC) dysfunction and impaired angiogenesis play a major role in the development of RV failure, and data obtained in the previous funding period demonstrate that the female sex steroid 17β-estradiol (E2) increases capillary density in the RV and stimulates angiogenesis in cultured cardiac ECs. The goal of this proposal is to identify novel and therapeutically targetable mechanisms by which E2 exerts protective effects on RV EC function in PH. We provide evidence that E2 exerts its RV EC-protective effects via its receptor ERα, and suggest a new mechanism by which ERα activates bone morphogenetic protein receptor 2 (BMPR2) signaling to upregulate apelin, a potent angiogenesis mediator and EC survival factor, whose regulation in the RV is not yet known. Based on these findings, we now put forward the novel hypothesis that E2 improves RV function in PH by ERα- and BMPR2-dependent up-regulation of EC apelin. We propose the following specific aims: 1) To establish that E2 increases capillary density in the RV via BMPR2-dependent increases in EC apelin, and 2) To identify the contribution of ERα to increasing capillary density in the RV. We generated a novel ERα knockout rat that will enable us to study the role of ERα in the rat pulmonary artery banding model, thus avoiding the pitfalls of prior studies of sex hormone signaling performed in PH models without RV failure. These studies will be complemented by studies of BMPR2-deficient rats and apelin-deficient mice. These loss- of-function studies will be accompanied by studies in which we interrogate the therapeutic potential of ERα agonists, BMPR2 activators and apelin receptor agonists. We will complement these in vivo studies with experiments in RV ECs isolated from rodents with RV failure and from patients with compensated (adaptive) or decompensated (maladaptive) RV hypertrophy. Endpoints investigated will include RV function and structure (by pressure volume loops and echocardiography), exercise capacity (measured as VO2 max via treadmill running), RV capillary density (quantified using unbiased stereology and lectin staining), angiogenesis assays (matrigel tube formation and transwell migration), BMPR2 and apelin signaling pathways, as well as mediators of angiogenesis and EC survival and apoptosis. The proposed studies are significant, since they will 1) identify ERα as a critical modulator of RV function and 2) establish a novel and therapeutically targetable E2-ERα- BMPR2-apelin axis in RV ECs. The proposed studies are innovative, since they, for the first time, will provide a molecular basis for E2's RV- and EC-protective effects in PH. In addition, they provide technical innovation through use of a newly generated ERα knockout rat model, through use of a new highly selective ERα agonist that will allow for mechanistic dissection of ERα’s role in ECs from failing RVs, and through use of unbiased stereology. Upon completion of the proposed studies, we will have identified ERα as a novel mediator of adaptive signaling in RV ECs. This may ultimately allow for the development of new RV-directed, non- hormonal treatments for both female and male veterans with PH and RV failure.

肺动脉高压（PH）和右心室（RV）功能障碍在退伍军人中极为常见。 80% 的退伍军人患有慢性阻塞性肺病、肺纤维化、睡眠呼吸障碍或 左心室功能障碍（收缩或舒张）会受到 PH 影响。更好的右心室功能与女性性别有关。 提高 PH 患者的生存率，并且女性患者比男性患者表现出更好的 RV 功能。 该提案建立在科学前提之上，即尽管 RV 功能和女性性别是主要决定因素 PH 中的生存率，不存在 RV 特异性或性类固醇导向疗法，并且存在内皮细胞 (EC) 功能障碍。 血管生成受损在 RV 衰竭的发生中起重要作用，之前获得的数据 资助期证明女性性类固醇 17β-雌二醇 (E2) 会增加 RV 中的毛细血管密度 并刺激培养的心脏 EC 中的血管生成。该提案的目标是新颖地识别和促进血管生成。 E2 对 PH We 中 RV EC 功能发挥保护作用的治疗靶向机制。 提供 E2 通过其受体 ERα 发挥其 RV EC 保护作用的证据，并提出了一种新的方法 ERα 激活骨形态发生蛋白受体 2 (BMPR2) 信号传导上调的机制 apelin 是一种有效的血管生成介质和 EC 生存因子，其在 RV 中的调节尚不清楚。 基于这些发现，我们现在提出了新的假设，即 E2 通过以下方式改善 PH 中的 RV 功能： 我们提出以下具体目标：1) 依赖于 ERα 和 BMPR2 的 EC apelin 上调。 确定 E2 通过 EC apelin 的 BMPR2 依赖性增加来增加 RV 中的毛细血管密度，以及 2) 为了确定 ERα 对增加 RV 毛细血管密度的贡献，我们生成了一种新型 ERα。 敲除大鼠使我们能够研究 ERα 在大鼠肺动脉结扎模型中的作用，从而 避免了先前在没有 RV 衰竭的 PH 模型中进行的性激素信号传导研究的陷阱。 这些研究将得到对 BMPR2 缺陷大鼠和 apelin 缺陷小鼠的研究的补充。 功能失调研究将伴随着我们质疑 ERα 治疗潜力的研究 我们将补充这些体内研究。 从 RV 衰竭的啮齿类动物和补偿性（适应性）或 失代偿（适应不良）右心室肥大的研究终点将包括右心室功能和结构。 （通过压力容量环和超声心动图）、运动能力（通过跑步机测量最大摄氧量） RV 毛细血管密度（使用无偏立体学和凝集素染色进行量化）、血管生成测定 （基质胶管形成和跨孔迁移）、BMPR2 和 apelin 信号通路以及介质 所提出的研究具有重要意义，因为它们将 1) 确定。 ERα 作为 RV 功能的关键调节剂，2) 建立一种新型且可治疗靶向的 E2-ERα- RV EC 中的 BMPR2-apelin 轴 拟议的研究具有创新性，因为它们首次提供了 E2 对 PH 的 RV 和 EC 保护作用的分子基础此外，它们还提供了技术创新。 通过使用新生成的 ERα 敲除大鼠模型，通过使用新的高选择性 ERα 激动剂 这将允许从失败的 RV 中机械剖析 ERα 在 EC 中的作用，并通过使用公正的 完成拟议的研究后，我们将确定 ERα 是一种新的介体。 RV EC 中的自适应信号传导最终可能允许开发新的 RV 导向的、非 对患有 PH 和 RV 衰竭的女性和男性退伍军人进行激素治疗。