MMP-2 Regulation in Aortic Aneurysm

描述(由申请人提供)： 腹主动脉瘤(AAA)是一种常见疾病，也是老年人死亡和发病的主要原因。肾下主动脉瘤的病因尚不清楚，尽管蛋白分解增加似乎是这一过程的基础。我们先前已经发现AAA组织中总的和加工/活性的基质金属蛋白酶-2(MMP2)在转录水平上的增加。我们小组最近的实验工作已经证实，AAA需要基质金属蛋白酶-2，这表明基质金属蛋白酶-2基因敲除的小鼠对动脉瘤诱导具有抵抗力。我们提供了令人振奋的新的初步数据，表明与动脉粥样硬化性闭塞症(AOD；无动脉瘤的动脉硬化)或对照组(轻微动脉硬化，无动脉瘤)患者相比，AAA患者皮肤中的MMP-2mRNA和蛋白水平增加。与AOD或对照组相比，AAA患者血浆基质金属蛋白酶-2水平也升高。这一最新发现提示全身性过度表达基质金属蛋白酶-2，并与腹主动脉瘤患者腹部手术后发生切口性疝气的已知倾向一致。在基质金属蛋白酶-2启动子中发现的单核苷酸多态中，只有一个通过破坏Sp-1结合位点来改变基质金属蛋白酶-2的蛋白水平。我们假设系统性的基质金属蛋白酶-2的失调导致了动脉瘤的形成。这项建议将通过以下方式研究基质金属蛋白酶-2代谢的多个方面：1)检测AAA、AOD和对照组患者血液中的基质金属蛋白酶-2蛋白水平；2)测定基质金属蛋白酶-2启动子中常见的功能多态在AAA和AOD患者中的频率；3)在小鼠AAA模型中确定短干扰RNA分子(SiRNA)抑制基质金属蛋白酶-2表达和防止动脉瘤形成的能力；4)确定巨噬细胞衍生的MT1-基质金属蛋白酶在基质金属蛋白酶-2激活中的作用。目标1的目标是开发一种AAA的筛查测试。目的2可以确定一个重要的潜在机制，并解释个体对AAA的易感性。将在AIM 3中测试的siRNA作为一种特定的分子工具在研究和治疗中具有巨大的潜力。基质细胞分泌基质金属蛋白酶与炎症细胞局部激活之间的相互作用(特异性靶点4)是基质生物学的一个重要基础问题。对这一提议提出的问题的回答将极大地促进我们目前对AAA和与基质破坏相关的其他炎症性疾病过程的了解。

DESCRIPTION (provided by applicant): Abdominal aortic aneurysm (AAA) is a common disease and a leading cause of death and morbidity in the elderly. The etiology of infrarenal aortic aneurysms remains obscure although increased proteolysis appears to be fundamental to this process. We have previously identified a transcriptionally-mediated increase in total and processed/active matrix metalloproteinase-2 (MMP-2) in AAA tissue. That MMP-2 is required for AAA has been established by recent experimental work from our group showing that MMP-2 knockout mice are resistant to aneurysm induction. We present exciting new preliminary data showing that MMP-2 mRNA and protein levels are increased in the skin of AAA patients in comparison to patients affected with atherosclerotic occlusive disease (AOD; atherosclerosis without aneurysms) or controls (minimal atherosclerosis, no aneurysm). Plasma MMP-2 levels are also increased in AAA compared to AOD or controls. This latest finding suggests systemic over-expression of MMP-2 and is consistent with the known propensity of AAA patients to get incisional hernias after abdominal surgery. Among the single nucleotide polymorphisms found in the MMP-2 promoter, only one alters MMP-2 protein levels by disrupting an Sp-1 binding site. We I hypothesize that systemic MMP-2 dysregulation leads to aneurysm formation. This proposal will investigate a number of aspects of MMP-2 metabolism by: 1) determining MMP-2 protein levels in the blood of a larger group of AAA, AOD and control patients; 2) determining the frequency of a common, functional polymorphism in the MMP-2 promoter in AAA and AOD patients; 3) determining the ability of short interfering RNA molecules (siRNA) to inhibit MMP-2 expression and prevent aneurysm formation in a murine AAA model; 4) determining the role of macrophage-derived MT1-MMP in the activation of MMP-2. The goal of aim 1 is to develop a screening test for AAA. Aim 2 could identify an important underlying mechanism and explain individual susceptibility to AAA. The siRNA to be tested in aim 3 has great potential as a specific molecular tool for investigation and therapy. The interaction between resident MMP production and local activation by inflammatory cells (specific aim 4) is an Important fundamental question in matrix biology. Answers to the questions addressed by this proposal will greatly advance our current knowledge of AAA and other inflammatory disease processes associated with matrix destruction.