Caveolar Defects Underlie the Genetic Origins of PAH

项目摘要 肺动脉高压（PAH）是一种所有年龄段的致命疾病。它会影响女性 目前的治疗对长期生存率的影响微乎其微，这可能是因为 忽视了发病机制。我们已经集中了相当大的努力来了解中央遗传 机制和途径，有助于PAH发病机制，从我们发现的 BMPR 2突变是PAH相关的主要基因。沿着我们的大部队 的PAH（FPAH）家族，其中大多数存在骨形态发生蛋白受体2突变 （BMPR 2）[60个家系]，我们构建了Bmpr 2突变小鼠模型（R899 X）， 呸。通过对症状前BMPR 2突变型PAH患者和我们的小鼠模型的检查，我们 已经能够确定疾病发展之前的几个主要分子事件。 其中值得注意的是，打击了caveolae的贩运。然而，这些事件中， 疾病发展的核心和旁观者尚未确定。此夕h PAH的BMPR 2独立形式的分子基础尚未阐明。为了解决这个 问题，我们进行了全外显子组测序的方法来研究PAH患者没有以前的 PAH的遗传病因学。这项分析确定了一个与人类PAH相关的新基因，caveolin-1 CAV 1是一种对小窝形成很重要的膜蛋白。重要的是， 在肺中的多种细胞类型的质膜中丰富，并且已经与多种 信号通路，包括BMPR 2，而Cav 1敲除小鼠没有小窝，并表现出肺 血管功能障碍基于CAV 1和BMPR 2突变的这种趋同，我们开发了我们的 假设小窝缺陷代表了一种常见的机制， 呸。为了验证这一假设，我们让经验丰富的基础科学家和内科科学家， 并建议在细胞、小鼠模型和人类患者中进行研究。在目标1中，我们将测试 假设在体外细胞中，小窝蛋白-1和BMPR 2突变破坏小窝运输， 随后在细胞水平上失调小窝依赖的信号传导途径。在目标2中， 将测试假设，在小鼠中，小窝依赖的硝化，音调和运输缺陷是 对PAH的发展至关重要。最后，在目标3中，我们将检验人类受试者 CAV 1或BMPR 2中的种系突变在小窝结构和内皮功能上有缺陷， 与PAH的发病率和严重程度相关。这些研究将提供新的基础 了解PAH核心途径的细胞和分子发病机制，并将提供 有望在未来转化开发PAH的有效治疗方法，这是非常需要的 这种悲惨的疾病。

PROJECT SUMMARY Pulmonary Arterial Hypertension (PAH) is a lethal disease of all ages. It affects women disproportionately and current therapy has marginal impact on longterm survival, perhaps because it neglects pathogenesis. We have focused considerable effort in understanding the central genetic mechanisms and pathways that contribute to PAH pathogenesis, beginning with our discovery of the association of BMPR2 mutations as the major gene associated with PAH. Along with our large cohort of families with PAH (FPAH), most of whom have mutation in bone morphogenetic protein receptor 2 (BMPR2) [60 families], we constructed a Bmpr2 mutation mouse model (R899X) which recapitulates PAH. Through examination of presymptomatic BMPR2 mutant PAH patients and our mouse model, we have been able to identify several major molecular events which precede development of disease. Notable among these is disruption of trafficking of caveolae. However, which of these events are central to disease development and which are bystanders has not yet been determined. Further, the molecular basis for BMPR2-independent forms of PAH has yet to be elucidated. To address this issue, we undertook a whole-exome sequencing approach to study PAH patients without previous genetic etiology for PAH. This analysis identified a novel gene associated with human PAH, caveolin-1 (CAV1), a membrane protein important for the formation of caveolae. Importantly, caveolae are abundant in plasma membrane of multiple cell types in the lung, and have been linked to multiple signaling pathways, including BMPR2, while Cav1 null mice have no caveolae and exhibit pulmonary vascular dysfunction. Based on this convergence of CAV1 and BMPR2 mutations, we developed our hypothesis that defects in caveolae represent a common mechanism underlying the genetic basis of PAH. To test this hypothesis, we have aligned experienced basic scientists and physician scientists, and propose to carry out studies in cells, mouse models, and human patients. In Aim 1 we will test the hypothesis, in cells in vitro, that caveolin-1 and BMPR2 mutations disrupt caveolae trafficking, subsequently dysregulating caveolae-dependent signaling pathways at the cellular level. In Aim 2 we will test the hypothesis, in mice, that caveolae-dependent defects in nitration, tone, and trafficking are central to the development of PAH. Finally, in Aim 3 we will test the hypothesis that human subjects with germline mutations in CAV1 or BMPR2 have defects in caveolar structure and endothelial function, which associate with PAH penetrance and severity. These investigations will provide new basic understanding about cell and molecular pathogenesis of pathways central to PAH, and will provide promise for the future translational development of effective therapy for PAH, which is greatly needed for this tragic disease.