ACE2 as a target for pulmonary hypertension therapeutics

描述（由申请人提供）：本申请是为了响应挑战资助计划而提交的，特别是再生挑战领域，计划11-HL 101，“开发CV、肺和血液疾病的细胞疗法”。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就业机会，2）它提出了一个新的和创新的治疗肺动脉高压（PH）的假设，一种无法治愈的毁灭性疾病，3）它将使我们能够快速-跟踪我们的研究，以1期临床试验的潜力，挽救成千上万的美国人的生命，并减少疾病相关的发病率在不久的将来。致命疾病PH的进展是由肺血管内皮功能障碍引发的。由于这一概念，血管舒张治疗一直是PH治疗的支柱，然而，尽管取得了一些成功，PH仍然是一种致命的疾病。我们相信这一建议描述了一个概念上的突破，迫切需要开发新的治疗方法，将预防，甚至治愈PH。血管紧张素转换酶2（ACE 2）是内皮细胞中存在的肾素-血管紧张素系统的关键酶。ACE 2产生血管紧张素-（1-7）[Ang-（1-7）]，其防止血管紧张素II（血管紧张素转化酶（ACE）的产物）的血管收缩、增殖、纤维化和炎症作用。我们假设ACE/ACE 2比例失衡是肺内皮功能障碍导致血管重塑和PH相关病理生理学的关键事件。我们的数据表明，肺基因转移过度表达肺ACE 2可预防甚至逆转动物模型中的PH。然而，这个新概念在临床前试验之前有一个困难需要克服。这涉及与病毒载体介导的基因转移至肺相关的有限成功。为了克服这一障碍，我们提出利用分化成内皮前体细胞（EPC）的造血干细胞（HSC），表达ACE 2或Ang-（1 -7），将ACE 2/Ang-（1 - 7）递送到损伤部位，以协调稳健的肺血管修复和逆转PH。我们提出三个具体目标来实现这一目标：目标1：在PH的野百合碱（MCT）大鼠模型中测试HSC在肺中ACE 2的过表达将逆转PH病理生理学。目的2：在缺氧大鼠模型和条件性敲除大鼠模型中，检测表达ACE 2或Ang-（1-7）的HSC的递送将逆转PH的假设。骨形态发生蛋白受体2（Bmpr 2）小鼠模型。目标3：我们将研究ACE 2/Ang-（1-7）-HSC通过增强内皮功能、减少平滑肌细胞增生和减少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ACE 2/Ang-（1-7）工程化自体EPC治疗PH的I期临床研究。该申请是对挑战资助计划#11 HL-101的响应，该计划在“开发CV，肺和血液疾病的细胞疗法”领域。目前肺动脉高压（PH）的治疗无效，因此PH仍然是一种致命的疾病。本研究的目的是使用基因修饰的造血干细胞将ACE 2或Ang-（1-7）递送到肺损伤部位，以协调稳健的肺血管修复和逆转PH。 公共卫生相关性：本申请是对挑战资助计划#11 HL-101的回应，该计划的领域是“开发用于CV、肺和血液疾病的基于细胞的疗法”。目前肺动脉高压（PH）的治疗无效，因此PH仍然是一种致命的疾病。本研究的目的是使用基因修饰的造血干细胞将ACE 2或Ang-（1-7）递送到肺损伤部位，以协调稳健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.