Exploration of key proteases and validation of biomarkers in genetically triggered thoracic aortic aneurysms

项目总结：胸主动脉瘤（TAA）是由于异常重塑而发生的 主动脉细胞外基质（ECM）。这一过程削弱了主动脉壁，并导致严重扩张， 通常以通常无症状的方式进展为破裂。有几种已充分描述的病因， 有助于TAA的形成和发展。这些包括遗传综合征，以及，非综合征 遗传的倾向目前的治疗选择是有限的，包括手术重建或内- 血管干预;这两种方法都没有解决导致疾病的潜在机制。公 描述了TAAs受到细胞内和细胞外机制的影响， 沉积和降解，部分是通过激活基质金属蛋白酶（MMPs）和增强 TGF-β信号传导。以前，本实验室确定膜结合型-1 MMP（MT 1-MMP）作为关键 通过其在MMP-2活化的细胞周围蛋白水解和细胞内蛋白水解中的作用， TGF-β信号传导。此外，我们证明了MT 1-MMP的磷酸化调节酶的功能， 通过改变其细胞位置，从而介导特定底物的进入，改变其在ECM重塑中的作用， 和TAA的整体进展。尽管我们对TAA病理学的理解有所进步，但这些 创新尚未转化为TAA的筛查、诊断、跟踪和治疗的发展。 因此，迫切需要不仅确定治疗靶点，而且开发非侵入性方法 用于早期检测威胁生命的主动脉并发症之前的TAA。我们实验室和其他机构的工作 已经证实特异性MMPs及其内源性抑制剂（TIMPs）与发病机制有关 TAA，和类似的发现已被证明与microRNA。我们实验室的初步数据显示， 建立了这些MMPs、TIMPs和microRNA可以在血浆中直接定量， 可能用于筛选患者TAA的存在和病因亚型的算法。 然而，关于这些分析物在遗传触发的个体中的循环水平知之甚少， TAA。重要的是，已建立的遗传性触发主动脉粥样硬化综合生物标本库- 动脉粥样硬化和心血管疾病（GenTAC）由采集的主动脉组织和血浆标本组成 与TAA相关的多种常见倾向的个体。因此，我们建议进行调查- 利用这一资源，为不同亚型的TAA提供新的治疗和诊断策略。雅阁- 因此，该建议的中心假设是MT 1-MMP的功能在不同的病因学中改变， TAA的亚型，并且这些亚型可通过MMP、TIMP和MMP的不同血浆谱来区分。 microRNA，将通过以下具体目标进行研究：（1）证明 MT 1-MMP在基因触发的胸主动脉瘤中的作用，以及（2）确认先前确定的血浆 用于鉴定具有遗传易感性的患者中的TAA的生物标志物组。

PROJECT SUMMARY: Thoracic aortic aneurysms (TAAs) develop as a consequence to abnormal remodeling of the aortic extracellular matrix (ECM). This process weakens the aortic wall and leads to gross dilation that typically progresses to rupture in a generally asymptomatic way. There are several well described etiologies that contribute to the formation and progression of TAA. These include genetic syndromes, as well as, non-syndromic inheritable predispositions. Current treatment options are limited and consist of surgical reconstruction or endo- vascular intervention; neither of which address the underlying mechanisms responsible for disease. It is well described that TAAs are influenced by both intra- and extra- cellular mechanisms that function to regulate matrix deposition and degradation, in part, through activation of the matrix metalloproteinases (MMPs) and enhanced TGF-β signaling. Previously, this laboratory identified the membrane-bound type-1 MMP (MT1-MMP) as a key mediator of TAA formation through its role in both pericellular proteolysis by activation of MMP-2 and intracellular TGF-β signaling. Furthermore, we demonstrated that phosphorylation of MT1-MMP regulates enzymatic function by altering its cellular location, thus mediating access to specific substrates, shifting its role in ECM remodeling and overall progression of TAA. Despite advancements in our understanding of the pathobiology of TAA, these innovations have yet to be translated into development of screening, diagnosis, tracking, and treatment of TAA. Therefore, there is an urgent need to not only identify therapeutic targets, but also develop non-invasive methods for the early detection of TAA preceding life threatening aortic complications. Work from our laboratory and others have confirmed that specific MMPs, and their endogenous inhibitors (TIMPs) are implicated in the pathogenesis of TAA, and similar findings have been demonstrated with microRNAs. Preliminary data from our laboratory has established that theses MMPs, TIMPs, and microRNAs can be directly quantitated in plasma, and levels can be potentially utilized in an algorithm for screening patients for both the presence and etiological subtype of TAA. However, little is known in regards to circulating levels of these analytes in individuals with genetically triggered TAA. Importantly, the established comprehensive biospecimen repository of Genetically Triggered Aortic Aneu- rysms and Cardiovascular Conditions (GenTAC) is composed of aortic tissue and plasma specimens collected from individuals of multiple common predispositions linked to TAA. Therefore, we propose an investigation uti- lizing this resource to derive novel therapeutic and diagnostic strategies for different subtypes of TAA. Accord- ingly, the central hypotheses of this proposal are that the function of MT1-MMP is altered in different etiological subtypes of TAA, and these subtypes are distinguishable by a distinct plasma profile of MMPs, TIMPs, and microRNAs, which will be examined through the following specific aims: (1) Demonstrate a differential role of MT1-MMP in genetically triggered thoracic aortic aneurysms, and (2) Confirm a previously identified plasma biomarker panel for identification of TAA in patients with genetic predisposition.