Extracellular Matrix Biomechanical Properties Contribute to Aneurysm Formation in Marfan Syndrome

项目总结/摘要 马凡氏综合征（MFS）是最常见的遗传性结缔组织疾病，由MFS基因突变引起。 FBN 1基因，每5,000人中就有1人受到影响。主动脉根部动脉瘤导致主动脉夹层或破裂， 导致预期寿命降低，除非进行预防性主动脉手术。正常情况下，主动脉壁 内稳态依赖于SMC在一个被称为ECM的过程中对ECM机械力的感知和响应。 机械传导ECM维持功能障碍导致主动脉壁硬化，但ECM的作用 动脉瘤发展中的机械传导仍然存在争议。此外，驱动焦点的机制 动脉瘤发展仅限于主动脉根（最接近主动脉瓣的节段）， FBN 1突变的系统性影响知之甚少。主动脉中的SMC来源于特定的 胚胎起源，例如主动脉根来自第二心脏区域（SHF）和升主动脉 节段起源于神经嵴（NC）。我们已经开发了一种体外诱导多能干细胞系统， 模型胚胎衍生的血管病理学。利用iPSC模型放弃了对手术的依赖性， 组织标本，并打开了个性化精准医疗的大门。我的初步工作表明， 在不同刚度的板上生长的iPSC衍生的SMC表现出对增加的细胞增殖的明显胚胎学反应。 ECM刚度。该研究将进一步加深我们对ECM-SMC机械转导的理解 在动脉瘤形成期间使用两个互补的瞄准器。目的1将评估ECM的转录组学效应 通过应用单细胞RNA测序， 细胞在不同硬度和ECM组成下生长。ECM的成分和力学性能 由每个胚胎起源SMC产生的细胞将与原子力显微镜和质谱进行比较。 光谱法目的2将通过利用iPSC衍生的SMC研究胚胎依赖性ECM硬化 转导以过表达甘露糖受体2（MRC 2）以表征体外细胞内胶原再循环。 将使用转基因谱系示踪小鼠模型表征TGF-β对MRC 2诱导的ECM的作用。 体内病理学这些研究将使我们更好地了解ECM成分的改变， 刚度影响ECM-SMC机械转导，以提供新的治疗靶点， 动脉瘤形成拟议的研究培训计划的特点是由一个多元化的委员会直接指导 临床科学家和获得最先进的设施和技术。该计划包括专业 发展和职业规划战略，利用心胸外科之间的合作资源， 心血管医学和心血管研究所，以最大限度地发挥我的培训潜力。

Project Summary/Abstract Marfan syndrome (MFS) is the most common inherited connective tissue disorder, caused by mutations in the fibrillin-1 (FBN1) gene, affecting 1 in 5,000 individuals. Aortic root aneurysms lead to aortic dissection or rupture, resulting in reduced life expectancy unless preventative aortic surgery is performed. Normally, aortic wall homeostasis depends on SMC sensing and responding to ECM mechanical force in a process called mechanotransduction. Dysfunctional ECM maintenance results in aortic wall stiffening, but the role of mechanotransduction in aneurysm development remains controversial. Furthermore, mechanisms driving focal aneurysm development restricted to the aortic root (the segment most proximal to the aortic valve) despite systemic effects of FBN1 mutations are poorly understood. SMCs populating the aorta are derived from specific embryologic origins such that the aortic root is derived from the second heart field (SHF) and ascending aortic segments arise from neural crest (NC). We have developed an induced pluripotent stem cell in vitro system to model embryologic derived vascular pathology. Utilizing an iPSC model relinquishes the dependance for surgical tissue specimens and opens the door for personalized precision medicine. My preliminary work showed that iPSC-derived SMC grown on varying stiffness plates demonstrated a distinct embryologic response to increasing ECM stiffness. The proposed study will advance our current understanding in ECM-SMC mechanotransduction during aneurysm formation using two complimentary aims. Aim 1 will assess the transcriptomic effects of ECM stiffness and composition on SMCs from both embryologic origins by applying single cell RNA sequencing to cells grown on varying stiffness and ECM composition. The composition and mechanical properties of ECM produced by each embryologic origin SMC will be compared with atomic force microscopy and mass spectrometry. Aim 2 will investigate embryologic dependent ECM stiffening by utilizing iPSC-derived SMCs transduced to overexpress mannose receptor 2 (MRC2) to characterized intracellular collagen recycling in vitro. A transgenic lineage traced murine model will be used to characterize TGF-b effects on MRC2 induced ECM pathology in vivo. These studies will generate a greater understanding of how altered ECM composition and stiffness influences ECM-SMC mechanotransduction to provide insight into new therapeutic targets to prevent aneurysm formation. The proposed research training plan features direct mentorship from a diverse committee of clinician-scientist and access to state-of-the-art facilities and techniques. The plan incorporates professional development and career planning strategies, utilizing collaborative resources between Cardiothoracic Surgery, Cardiovascular Medicine, and the Cardiovascular Institute to maximize my training potential.