Mechanotransduction and YAP/TAZ Signaling in Pulmonary Arterial Hypertension

项目摘要/摘要： 肺动脉高压(PAH)的特点是细胞过度增殖和抗细胞凋亡 肺动脉内皮细胞(PAEC)、平滑肌细胞(PASMC)和外膜成纤维细胞(PAAF) 导致肺血管阻力进行性增加，最终导致右心衰竭和死亡。 最近的研究表明，肺动脉(PA)僵硬与心脏病死亡率的增加有关。 PAH患者；然而，PA硬化的发病和进展机制 多环芳烃尚未完全阐明。我们发现远端血管基质硬化发生在早期。 建立肺动脉高压(PH)模型，并触发局部机械生物反馈环路，放大 血管重塑并加速疾病进展。这些发现表明，PA僵硬不是 仅仅是血管壁病理变化的结果，但本身可以驱动异常的细胞行为。 我们已经确定YAP和TAZ是僵硬依赖的PASMC和PAEC的关键调节因子 多环芳烃中的机械活化。我们的初步发现表明，通过YAP/TAZ驱动器的机械信号 通过抑制环氧合酶(COX)-2衍生的前列腺素合成激活血管细胞 骨形态发生蛋白(BMP)信号传导。PASMC和PAEC中YAP/TAZ的沉默消除了刚性- 依赖于增殖、基质沉积和牵引力的增加，并挽救抑制 前列腺素的产生和BMP信号的传递。此外，PASMC过表达突变的TAZ定位 COX-2衍生的前列腺素合成和BMP显著减少 导致高增殖性重塑表型的信号。我们假设YAP/TAZ是由 机械环境驱动前重塑细胞反应和促进基质硬化 在PAH中通过抑制前列腺素类物质的产生和BMP信号的负反馈循环。在目标1中，我们将 探讨YAP/TAZ在调节COX-2依赖的前列腺素合成和血管生成中的作用 PAH中对基质硬化的反应。我们将确定YAP/TAZ依赖抑制的机制 COX-2在人PASMC，PAEC，PASMC，PAEC中对僵硬依赖的收缩和基质合成的调节 还有帕夫。在目标2中，我们将研究YAP/TAZ控制TGF-！的机制。和BMP依赖 Smad信号，抑制Id1的表达，并调节PAH中对BMP信号的细胞生长反应。 我们将确定YAP/TAZ活性对细胞增殖、抗凋亡和迁移的影响 伴有和不伴有BMPR2突变的PAH患者的PASMC、PAEC和PAAF。在目标3中，我们将确定 YAP/TAZ失活是否能阻止PA硬化、抑制血管重塑和防止右 实验性高血压性心脏病患者的右室功能障碍。我们将使用小鼠模型和药理学方法 调节YAP/TAZ的活性，并评估YAP/TAZ失活对PA硬化、血流动力学、 肺动脉高压模型中右室功能障碍、血管重塑以及前列腺素和骨形态发生蛋白通路的调节。

PROJECT SUMMARY/ABSTRACT: Pulmonary arterial hypertension (PAH) is characterized by excessive proliferation of apoptosis-resistant pulmonary artery endothelial cells (PAEC), smooth muscle cells (PASMC), and adventitial fibroblasts (PAAF) leading to progressive increases in pulmonary vascular resistance, and ultimately right heart failure and death. Recent studies suggest that pulmonary arterial (PA) stiffness is associated with increased mortality in patients with PAH; however, the mechanisms involved in the pathogenesis and progression of PA stiffening in PAH have yet to be fully elucidated. We have discovered that distal vascular matrix stiffening develops early in models of pulmonary hypertension (PH) and triggers a local mechanobiological feedback loop that amplifies vascular remodeling and accelerates disease progression. These findings suggest that PA stiffness is not merely a consequence of pathologic changes in the vessel wall, but can itself drive abnormal cellular behavior. We have identified YAP and TAZ as pivotal regulators of stiffness-dependent PASMC and PAEC mechanoactivation in PAH. Our preliminary findings suggest that mechanosignaling via YAP/TAZ drives vascular cell activation through suppression of cyclooxygenase (COX)-2-derived prostanoid production and bone morphogenetic protein (BMP) signaling. Silencing of YAP/TAZ in PASMC and PAEC abrogates stiffness- dependent increases in proliferation, matrix deposition, and traction force generation, and rescues suppression of prostanoid production and BMP signaling. Moreover, PASMC overexpressing a mutant TAZ that localizes constitutively to the nucleus have a dramatic reduction in COX-2-derived prostanoid production and BMP signaling leading to a hyperproliferative remodeling phenotype. We hypothesize that YAP/TAZ are activated by the mechanical environment to drive pro-remodeling cellular responses and promote matrix stiffening in an adverse feedback loop via suppression of prostanoid production and BMP signaling in PAH. In Aim 1, we will investigate the role that YAP/TAZ play in regulating COX-2-dependent prostaglandin production and vascular responses to matrix stiffening in PAH. We will determine the mechanisms of YAP/TAZ-dependent suppression of COX-2 and regulation of stiffness-dependent contractility and matrix synthesis in human PASMC, PAEC, and PAAF. In Aim 2, we will examine the mechanisms by which YAP/TAZ control TGF-! and BMP-dependent Smad signaling, suppress Id1 expression, and regulate cellular growth responses to BMP signaling in PAH. We will determine the impact of YAP/TAZ activity on proliferation, apoptosis resistance, and migration in PASMC, PAEC, and PAAF from PAH patients with and without BMPR2 mutations. In Aim 3, we will determine whether inactivation of YAP/TAZ arrests PA stiffening, attenuates vascular remodeling, and prevents right ventricular (RV) dysfunction in experimental PH. We will use murine models and pharmacologic approaches to modulate YAP/TAZ activity and assess the effects of YAP/TAZ inactivation on PA stiffening, hemodynamics, RV dysfunction, vascular remodeling, and regulation of the prostanoid and BMP pathways in models of PH.