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（RV）功能障碍在退伍军人中极为常见。到 80％的退伍军人患有慢性阻塞性肺部疾病，肺纤维化，睡眠无序呼吸或 LV功能障碍（收缩期或舒张期）患有pH。更好的RV功能和女性已经联系 为了提高pH的生存率，女性患者的RV功能比其男性表现更好。这 提案以科学前提为基础，即即使RV功能和女性是主要的决定者 pH中的生存性，不存在RV特异性或性类固醇指导的疗法。内皮细胞（EC）功能障碍和 受损的血管生成在RV衰竭的发展中起主要作用，并且在先前获得的数据 资金期表明，女性性类固醇17β-雌二醇（E2）增加了RV的毛细血管密度 并刺激培养的心脏EC中的血管生成。该提议的目的是确定小说和 E2对pH中RV EC功能的保护作用的治疗定位机制。我们 提供证据表明E2通过其接收器ERα执行其RV EC保护作用，并提出新的 ERα激活骨形态学蛋白受体2（BMPR2）信号传导的机制以更新 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，我们现在提出了一个新的假设，即E2改善了pH中的RV功能 EC呼吸素蛋白的ERα-和BMPR2依赖性上调。我们提出以下具体目的：1） 确定E2通过BMPR2依赖性EC丙蛋白酶的增加而增加RV中的毛细血管密度，而2） 确定ERα对增加RV毛细血管密度的贡献。我们产生了一个新颖的ERα 敲除大鼠将使我们能够研究ERα在大鼠肺动脉带模型中的作用，从而 避免在没有RV失败的情况下在pH模型中进行的性别同性信号传导的先前研究的陷阱。 这些研究将通过对BMPR2缺陷大鼠和Apelin缺陷小鼠的研究完成。这些损失 - 功能研究将通过研究来完成，我们询问ERα的治疗潜力 激动剂，BMPR2激活剂和Apelin受体激动剂。我们将通过 从RV失败的啮齿动物中分离出的RV EC的实验以及已完成（自适应）或 代偿性（适应不良的）RV肥大。调查的端点将包括RV功能和结构 （通过压力量环和超声心动图），锻炼能力（通过跑步机测量为VO2 Max 跑步），RV毛细管密度（使用无偏立即学和秘书染色定量），血管生成测定 （Matrigel管的形成和Transwell迁移），BMPR2和Apelin信号通路以及介体 血管生成和EC生存和凋亡。拟议的研究很重要，因为它们会1）确定 ERα作为RV函数的关键调节剂，2）建立一种新颖且具有治疗靶向的E2-ERα- RV ECS中的BMPR2-紫罗兰轴。拟议的研究具有创新性，因为它们首次将提供 E2在pH中的RV和EC保护作用的分子基础。此外，它们提供技术创新 通过使用新生成的ERα基因敲除大鼠模型，通过使用新的高度选择性ERα激动剂 这将使ERα在EC中的作用进行机械解剖，并通过使用无偏见 立体论。拟议的研究完成后，我们将确定ERα是一个新的介体 RV EC中的自适应信号传导。这最终可能允许开发新的RV定向，非 - pH和RV衰竭的女性和男性退伍军人的荷尔蒙治疗。