ACE2 as a target for pulmonary hypertension therapeutics

描述（由申请人提供）：本申请是根据挑战资助计划提交的，特别是再生挑战领域，项目11-HL 101，“开发基于细胞的治疗心血管、肺部和血液疾病”。该提案满足了2009年ARAA的所有期望：1)它将为美国公民创造两个新的工作岗位；2)它提议研究一种治疗肺动脉高压（PH）的新颖和创新的假设，这是一种无法治愈的毁灭性疾病；3)它将使我们的研究快速进入第一阶段临床试验，有可能在不久的将来挽救成千上万的美国人的生命，并减少与疾病相关的发病率。致命疾病PH的进展是由肺血管内皮功能障碍引起的。由于这一概念，血管扩张疗法一直是治疗PH的主要方法，然而，尽管取得了一些成功，PH仍然是一种致命的疾病。我们认为，这一提议描述了一个概念上的突破，迫切需要开发新的治疗方法来预防甚至治愈ph。血管紧张素转换酶2 （ACE2）是内皮细胞中肾素-血管紧张素系统的关键酶。ACE2产生血管紧张素-(1-7)[Ang-(1-7)]，它可以阻止血管紧张素转换酶（ACE）的产物Ang II的血管收缩、增殖、纤维化和炎症作用。我们假设ACE/ACE2比例失衡是导致血管重塑和PH相关病理生理的肺内皮功能障碍的关键事件。我们的数据表明，在动物模型中，通过肺基因转移过度表达肺ACE2可以阻止甚至逆转PH，这一假设得到了支持。然而，在临床前试验之前，这个新概念有一个困难需要克服。这与病毒载体介导的基因转移到肺的有限成功有关。为了克服这一障碍，我们建议利用造血干细胞（HSC）分化为内皮前体细胞（EPC），表达ACE2或Ang-(1-7)，将ACE2/Ang-(1-7)传递到损伤部位，以协调强大的肺血管修复和逆转PH。我们提出了三个具体目标来实现这一目标：目标1：在单核胆碱（MCT）大鼠PH模型中，测试肺中HSC过表达ACE2将逆转PH病理生理。验证在缺氧大鼠模型和骨形态发生蛋白受体2 （Bmpr2）小鼠模型中，传递表达ACE2或Ang-(1-7)的HSC可逆转PH的假设。目的3：我们将研究ACE2/Ang-(1-7)- hsc通过增强内皮功能、减少平滑肌细胞增生和降低促炎细胞因子而具有保护作用的假设。这些研究将使我们能够将我们的研究转化为使用ACE2/Ang-(1-7)工程自体EPC治疗ph的1期临床研究。该申请是对“开发CV，肺和血液疾病的细胞基础疗法”领域的挑战资助计划# 11HL-101的回应。目前治疗肺动脉高压（PH）是无效的，因此PH仍然是一种致命的疾病。在这项研究中，我们的目标是使用转基因造血干细胞将ACE2或Ang-(1-7)传递到肺损伤部位，以协调一个强大的肺血管修复和逆转PH。

DESCRIPTION (provided by applicant): This application is submitted in response to the Challenge Grant Program, specifically the Regeneration challenge area, program 11-HL 101, "Develop cell based therapies for CV, lung and blood disease". The proposal fulfills all the expectations of the ARAA of 2009: 1) It will create two new jobs to the American citizens, 2) It proposes to investigate a novel and innovated hypothesis for the treatment of pulmonary hypertension (PH), a devastating disease without a cure and 3) it will allow us to fast-track our studies to a phase 1 clinical trial with the potential of saving thousands of American lives and reducing disease associated morbidity in the immediate future. The progression of the fatal disease PH is set in motion by pulmonary vascular endothelial dysfunction. As a result of this concept, vasodilatory therapy has been the mainstay of PH treatment however, despite some success, PH remains a deadly disease. We believe this proposal described a conceptual breakthrough that is urgently needed to develop the novel therapeutics that will prevent and even cure PH. Angiotensin converting enzyme 2 (ACE2) is the key enzyme of the renin-angiotensin system present in endothelial cells. ACE2 produces angiotensin-(1-7) [Ang-(1-7)] which prevents the vasoconstrictive, proliferative, fibrotic and inflammatory effects of Ang II, a product of angiotensin converting enzyme (ACE). We hypothesize that an imbalance in the ACE/ACE2 ratio is the key event in pulmonary endothelial dysfunction leading to the vascular remodeling and the pathophysiology associated with PH. This hypothesis has been supported by our data demonstrating that overexpression of pulmonary ACE2 by lung gene transfer prevents and even reverses PH in animal models. This novel concept, however, has one difficulty to overcome before its preclinical trial. This relates to a limited success associated with viral vector mediated gene transfer to the lung. To overcome this obstacle, we propose to utilize hematopoietic stem cells (HSC) that differentiate into endothelial precursor cells (EPC), expressing ACE2 or Ang-(1-7) to deliver ACE2/Ang-(1-7) to sites of injury to orchestrate robust pulmonary vascular repair and reverse PH. We propose three specific aims to accomplish this objective: Aim 1: Test that overexpression of ACE2 by HSC in the lungs will reverse PH pathophysiology in the monocrotaline (MCT) rat model of PH. Aim 2: Test the hypothesis that delivery of HSC expressing ACE2 or Ang-(1-7) would reverse PH in the hypoxia rat model and the conditional knock-in of bone morphogenetic protein receptor 2 (Bmpr2) mouse model. Aim 3: We will investigate the hypothesis that ACE2/Ang-(1-7)-HSC will be protective by enhancing endothelial function, reducing smooth muscle cell hyperplasia and decreasing proinflammatory cytokines. These studies will position us to translate our investigation into a phase 1 clinical study for the use of ACE2/Ang-(1-7) engineered autologous EPC for the treatment of PH. This application is in response to Challenge Grant Program # 11HL-101 in the area of "Develop cell based therapies for CV, lung, and blood disease". Current therapy for pulmonary hypertension (PH) is not effective and as a result PH remains a fatal disease. Our objective in this investigation is to use genetically modified hematopoietic stem cells to deliver ACE2 or Ang-(1-7) to the site of pulmonary injury to orchestrate a robust pulmonary vascular repair and reverse PH. PUBLIC HEALTH RELEVANCE: This application is in response to Challenge Grant Program # 11HL-101 in the area of "Develop cell based therapies for CV, lung, and blood disease". Current therapy for pulmonary hypertension (PH) is not effective and as a result PH remains a fatal disease. Our objective in this investigation is to use genetically modified hematopoietic stem cells to deliver ACE2 or Ang-(1-7) to the site of pulmonary injury to orchestrate a robust pulmonary vascular repair and reverse PH.