REGULATED EXPRESSION OF COLLAGENASES IN AAA

腹主动脉瘤（AAAs）是一种常见的危及生命的退行性疾病。虽然AAA发生的病理生理事件尚不清楚，但它们显然与主动脉壁结缔组织的退行性重塑有关。最近的研究表明，在这种病理重塑模式中有三个过程：(1)纤维细胞外基质蛋白的修复受损，(2)慢性单核炎症，(3)局部过量产生基质降解蛋白酶。这项合作研究计划的目的是为了更好地了解调节这三个过程的分子机制。首先,Drs。William C. Parks和J. Michael Shipley将研究限制动脉瘤壁环境中弹性纤维有效生成的分子因素。他们将利用从人类和实验性AAA和动脉瘤来源的血管平滑肌细胞中获得的组织进行培养，具体评估控制tropoelastin基因表达和tropoelastin mRNA稳定性的分子途径，以及参与弹性纤维组装的其他基因产物的调控，如fibrin -1和潜在的tgf - β结合蛋白-2。其次，Jay Heinecke博士将研究与慢性炎症相关的蛋白质氧化作为组织破坏的重要途径。利用新方法检测和测量不同氧化途径对蛋白质修饰的贡献，他将确定人类和实验AAA中的主要氧化途径，阐明蛋白质氧化如何促进动脉瘤组织中基质金属蛋白酶的活性，并研究基因操作如何影响特定氧化途径可能改变小鼠模型中的动脉瘤发展。第三，Robert W. Thompson博士将研究三种不同间质胶原酶的调控表达，包括不同疾病阶段的人类AAA组织和暴露于促炎细胞因子、磷酯和强力霉素的培养SMC。这些研究将特别关注胶原酶-3 (MMP-13)，为血管壁细胞中MMP-13的表达调控提供新的见解。通过这三个密切相关的研究获得的知识将有助于提高我们对主动脉瘤分子病理生理学的理解，可能导致新的治疗策略。

Abdominal aortic aneurysms (AAAs) are a common degenerative disease with life-threatening implications. While the pathophysiologic events underlying the development of AAA are still poorly understood, they clearly involve degenerative remodeling of aortic wall connective tissue. Recent studies have implicated three processes in this pathologic pattern of remodeling: (1) impaired repair of fibrillar extracellular matrix proteins, (2) chronic mononuclear inflammation, and (3) excessive local production of matrix-degrading proteinases. The purpose of this collaborative research program is to gain better understanding of the molecular mechanisms regulating these three processes. First, Drs. William C. Parks and J. Michael Shipley will examine the molecular factors that appear to limit the effective production of elastic fibers in the aneurysm wall environment. Using tissues obtained from human and experimental AAA and aneurysm-derived vascular smooth muscle cells in culture, they will specifically evaluate the molecular pathways controlling tropoelastin gene expression and tropoelastin mRNA stability, as well as the regulation of additional gene products involved in elastic fiber assembly, such as fibrillin-1 and latent TGF-beta binding protein-2. Second, Dr. Jay Heinecke will examine protein oxidation associated with chronic inflammation as an important pathway of tissue destruction. Using novel methods to detect and measure the contributions of different oxidative pathways to protein modification, he will determine the dominant oxidative pathways in human and experimental AAA, elucidate how protein oxidation serves to promote matrix metalloproteinase activity in aneurysm tissue, and examine how genetic manipulation affecting specific oxidative pathways might alter aneurysm development in a mouse model. Third, Dr. Robert W. Thompson will examine the regulated expression of three different interstitial collagenases, both in human AAA tissues from various stages of disease and in cultured SMC exposed to proinflammatory cytokines, phorbol ester and doxycycline. These studies will have a particular focus on collagenase-3 (MMP-13), providing new insight into the regulation of MMP-13 expression in vascular wall cells. Knowledge gained through these three closely-linked studies will help advance our understanding of the molecular pathophysiology of aortic aneurysms, potentially leading to new treatment strategies.