Caveolar Defects Underlie the Genetic Origins of PAH

项目总结 肺动脉高压(PAH)是所有年龄段的致命性疾病。它会影响女性 不成比例的当前治疗对长期生存的影响微乎其微，或许是因为它 忽略了发病机制。我们已经集中了相当大的努力来理解中心基因 PAH发病的机制和途径，从我们发现 BMPR2基因突变与PAH的相关性研究以及我们的一大群人 在PAH(FPAH)家系中，大多数人有骨形态发生蛋白受体2突变 (BMPR2)[60个家系]，我们构建了一种Bmpr2突变小鼠模型(R899X)，该模型概括了 啊哈。通过对症状前BMPR2突变的PAH患者和我们的小鼠模型的检查，我们 已经能够识别出疾病发展之前的几个主要分子事件。 其中值得注意的是破坏了洞穴的贩运。然而，这些事件中有哪些是 谁是疾病发展的核心，谁是旁观者尚未确定。此外， BMPR2非依赖形式的PAH的分子基础尚未阐明。要解决这个问题 我们采用了全外显子组测序的方法来研究PAH患者。 PAH的遗传病因学。这项分析发现了一个与人类PAH相关的新基因，小窝蛋白-1 (CAV1)，一种对小窝的形成起重要作用的膜蛋白。重要的是，凹陷是 在肺中丰富的多种细胞类型的质膜中，并已与多个 信号通路，包括BMPR2，而Cav1基因缺失的小鼠没有小窝，表现为肺 血管功能障碍。基于CAV1和BMPR2突变的这种趋同，我们开发了我们的 假设小窝缺陷代表着一种共同的机制，其遗传基础 啊哈。为了验证这一假设，我们联合了经验丰富的基础科学家和内科科学家， 并提议在细胞、小鼠模型和人类患者中进行研究。在目标1中，我们将测试 在体外细胞中，假设小窝蛋白-1和BMPR2突变破坏了小窝的运输， 随后，在细胞水平上失调了小窝依赖的信号通路。在《目标2》中，我们 将在小鼠身上检验这一假设，即依赖于小窝的硝化、音调和运输缺陷是 对多环芳烃的发展至关重要。最后，在目标3中，我们将测试人类受试者的假设 CAV1或BMPR2的胚系突变在凹陷结构和内皮功能方面存在缺陷， 它们与PAH的外显性和严重性有关。这些调查将提供新的基础 对PAH中心通路的细胞和分子发病机制的理解，并将提供 为PAH有效治疗的未来翻译开发提供了希望，这是非常需要的 为这场悲惨的疾病。

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.