NHE1 signaling in Pulmonary Arterial Hypertension

肺动脉高压中的 NHE1 信号传导

• 批准号: 8968760
• 负责人: John Huetsch
• 金额: $ 5.9万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8968760
• 关键词: Actins; Affect; Basic Science; Binding; Binding Proteins; Biological Assay; Blood Vessels; Cell Proliferation; Cell Shape; Cell physiology; Cells; Chronic; Co-Immunoprecipitations; Data; Development; Disease; Goals; Heart failure; Human; Hypoxemia; Hypoxia; Hypoxia Pathway; In Vitro; Incubated; Infection; Injection of therapeutic agent; Ions; Knockout Mice; Laboratories; Lung; Mediating; Microfilaments; Migration Assay; Modeling; Morbidity - disease rate; Mus; NHE1; Pathogenesis; Pathologic; Pathology; Pathway interactions; Patients; Physicians; Play; Prevention; Prevention Protocols; Proteins; Pulmonary Hypertension; Pulmonary artery structure; Pulmonology; Rattus; Research; Role; SU 5416; Scientist; Signal Pathway; Signal Transduction; Small Interfering RNA; Smooth Muscle Myocytes; Sodium-Hydrogen Antiporter; Syndrome; Testing; Training; Transfection; Up-Regulation; Vascular remodeling; Wistar Rats; Work; World Health Organization; career; cariporide; cell motility; crosslink; efficacy testing; ezrin; hypertension control; hypoxia inducible factor 1; in vitro Model; in vivo Model; inhibitor/antagonist; mRNA Expression; migration; mortality; mutant; new therapeutic target; novel; overexpression; prevent; protein expression; public health relevance; pulmonary arterial hypertension; response; targeted treatment; transcription factor; vasoconstriction

DESCRIPTION (provided by applicant): Pulmonary hypertension (PH) is a syndrome which the World Health Organization subdivides into five classes, including Group I pulmonary arterial hypertension (PAH), which is PH due to pathology of the precapillary pulmonary vasculature, and Group III, which is PH due to chronic hypoxemia. The pathogenesis of PAH remains poorly understood and, despite advances in therapy, mortality due to PAH remains high. Our laboratory has identified a novel signaling pathway which is necessary for the development of hypoxia- induced PH in mice. In this pathway, hypoxia induces activation of the transcription factor HIF-1 in pulmonary artery smooth muscle cells (PASMCs); HIF-1 in turn upregulates expression of the transmembrane ion exchanger NHE1, which effects changes in PASMC migration and proliferation that contribute to the pathologic pulmonary vascular remodeling that leads to PH. Interestingly, HIF-1 expression has been found to be increased in normoxic PASMCs from human patients with PAH, in comparison with normal controls. Furthermore, our preliminary studies show that NHE1 activity is increased in PASMCs in PAH models compared to controls. Therefore, the focus of this proposal is to determine the role of the NHE1 signaling pathway in the development of PAH as well as to test the efficacy of NHE1 inhibitors in the treatment of PAH. The long-term goal is that, by elucidating new pathways that contribute to the pathogenesis of PAH, we may discover novel targets for therapy. We will employ two models of PAH: an in vitro model comparing PASMCs from PAH patients to those from normal patients, and an in vivo model comparing rats, in which PAH is induced through the combination of Sugen exposure and hypoxia, to normoxic rats. In Specific Aim 1, we will determine whether NHE1 expression is increased in PAH models and, if so, whether NHE1 upregulation in PAH is dependent upon HIF-1. Through overexpression as well as silencing of NHE1, we will determine whether NHE1 levels in PASMCs contribute to pathologic PASMC proliferation and migration. In Specific Aim 2, we will determine the efficacy of cariporide, a specific NHE1 inhibitor, in the prevention and reversal of PAH in our rat model, as well as the effect of cariporide on human PASMC function in our in vitro model. In addition to determining the role of NHE1 in the pathogenesis of PAH, execution of this proposal will provide training for the candidate that will be instrumental toward his career goal of becoming a physician- scientist performing basic science research in the field of pulmonary medicine.

描述（申请人提供）：肺动脉高压（PH）是世界卫生组织将其分为五类的综合征，包括第一类肺动脉高压（PAH），这是由于毛细血管前肺血管病变引起的PH，以及第三类，这是由于慢性低氧血症引起的PH。 PAH 的发病机制仍然知之甚少，尽管治疗方法取得了进步，但 PAH 引起的死亡率仍然很高。 我们的实验室已经确定了一种新的信号通路，它对于小鼠缺氧诱导的 PH 的发展是必需的。在该通路中，缺氧会诱导肺动脉平滑肌细胞（PASMC）中转录因子 HIF-1 的激活； HIF-1 反过来上调跨膜离子交换剂 NHE1 的表达，从而影响 PASMC 迁移和增殖的变化，从而导致病理性肺血管重塑，从而导致 PH。有趣的是，与正常对照相比，人类 PAH 患者的含氧量正常的 PASMC 中 HIF-1 的表达有所增加。此外，我们的初步研究表明，与对照组相比，PAH 模型中 PASMC 中的 NHE1 活性有所增加。因此，本提案的重点是确定NHE1信号通路在PAH发生过程中的作用以及测试NHE1抑制剂在治疗PAH中的疗效。长期目标是，通过阐明导致 PAH 发病机制的新途径，我们可能会发现新的治疗靶点。 我们将采用两种 PAH 模型：一种是比较 PAH 患者与正常患者 PASMC 的体外模型，另一种是比较大鼠（其中通过 Sugen 暴露和缺氧联合诱导 PAH）与含氧量正常的大鼠的体内模型。在具体目标 1 中，我们将确定 PAH 模型中 NHE1 表达是否增加，如果是，PAH 中 NHE1 上调是否依赖于 HIF-1。通过 NHE1 的过度表达和沉默，我们将确定 PASMC 中的 NHE1 水平是否有助于病理性 PASMC 增殖和迁移。在具体目标 2 中，我们将确定卡立波利（一种特定的 NHE1 抑制剂）在大鼠模型中预防和逆转 PAH 的功效，以及卡立波利在体外模型中对人 PASMC 功能的影响。 除了确定 NHE1 在 PAH 发病机制中的作用外，该提案的执行还将为候选人提供培训，这将有助于他成为一名在肺医学领域进行基础科学研究的医师科学家的职业目标。