Premature Aging, Vascular Disease and Endothelial Mechanotransduction

项目摘要 早衰综合征是几种已知的罕见突变导致多器官系统功能障碍的结果，其特征是正常衰老的特征，如骨质疏松症、脱发和皮肤皱纹。例如，哈钦森-吉尔福德早衰综合征(HGPS)和沃纳-S综合征(WS)的患者会受到加速的过早动脉粥样硬化的影响，从而导致心脏病发作和中风。正如家族性高胆固醇血症和家族性载脂蛋白B-100缺陷等单基因疾病为动脉粥样硬化的发病机制提供了强大的分子基础一样，过早衰老综合征可能为揭示参与动脉粥样硬化形成的新的关键途径提供了机会。虽然已有多条研究路线开始探索与这些综合征相关的血管缺陷，但血管内皮细胞在与HGPS和WS相关的血管疾病的发病机制中的参与尚不清楚。 我们的实验室和其他实验室已经证明，内皮功能障碍是血管疾病发展过程中的早期关键事件，它构成了心脏和血管衬里的重要功能的多方面损害。我们已经证明，这种功能障碍可以由生物力学刺激的存在或不存在引起。生物力学在血管内皮细胞功能中起着重要作用，特别是在根据特定的生物力学刺激诱发动脉粥样硬化抵抗或动脉粥样硬化易感表型方面。这些不同的细胞表型是由特定的机械敏感信号通路激活的遗传程序的结果，以响应人类动脉树中存在的动脉粥样硬化保护或动脉粥样硬化剪切力。基于这些观察，生物机械力可以被认为是动脉粥样硬化形成的局部危险因素。在这里，我的工作假设是，动脉粥样硬化在早衰综合征中的早期出现是内皮细胞对动脉粥样硬化保护性剪应力反应障碍的结果。 为了验证这一假设，在特定的目标1中，我们将首先从正常、HGPS和WS患者的成纤维细胞中分离出诱导多能干细胞(IPS)。在特定的目标2中，我们将这些iPS细胞分化为内皮细胞。我们将严格描述这种内皮细胞的结构和功能，以确保它具有成熟的动脉特征。为了确保这一点，在特定的目标3中，我们将使正常和过早衰老的iPS细胞来源的内皮细胞受到成人血管系统中存在的剪切应力波形，并评估由此产生的内皮细胞表型。这将表明早衰模型内皮是否由于机械转导功能障碍而易患动脉粥样硬化。

Project Summary Premature aging syndromes are the result of several identified rare mutations leading to the dysfunction of multiple organ systems characterized by features of normal aging such as osteoporosis, alopecia and skin wrinkling. Patients with Hutchinson-Gilford Progeria Syndrome (HGPS) and Werner¿s Syndrome (WS) for example, are affected by accelerated, premature atherosclerosis leading to heart attacks and strokes. Just as monogenic diseases such as familial hypercholesterolemia and familial defective apoB-100 have provided powerful molecular insights into the pathogenesis of atherosclerosis, premature aging syndromes may offer an opportunity to expose new critical pathways involved in atherogenesis. While several lines of investigation have begun to probe the vascular defects associated with these syndromes, the involvement of vascular endothelium in the pathogenesis of the vascular disease associated with HGPS and WS remains unexplored. Our laboratory and others have shown that endothelial dysfunction, which constitutes a multifaceted impairment of the vital functions of the lining of the heart and blood vessels, is an early critical event in the development of vascular disease. We have shown that this dysfunction can be caused by the presence or absence of biomechanical stimuli. Biomechanical forces are important players in endothelial function, particularly in evoking atherosclerosis-resistant or atherosclerosis-susceptible phenotypes depending on the specific biomechanical stimulus. These distinct cellular phenotypes are the result genetic programs activated by specific mechanosensitive signaling pathways in response to atheroprotective or atheroprone shear stress present in the human arterial tree. Based on these observations, biomechanical forces can be considered ¿local risk factors¿ in atherogenesis. Here, it is my working hypothesis that the early appearance of atherosclerosis in premature aging syndromes is a consequence of dysfunctional endothelial cell responsiveness to atheroprotective shear stress. To test this hypothesis, in Specific Aim 1, we will first create induced pluripotent stem (iPS) cells from fibroblasts that have been harvested from normal, HGPS and WS human patients. In Specific Aim 2, we will differentiate these iPS cells into endothelium. We will rigorously characterize this endothelium both structurally and functionally to ensure it has a mature, arterial identity. Assured of this, in Specific Aim 3, we will subject the normal and premature aging model iPS cell-derived endothelium to shear stress waveforms present in the adult human vasculature and assess the resulting endothelial phenotype. This will indicate whether the premature aging model endothelium is predisposed atherosclerosis due to dysfunctional mechanotransduction.