Molecular Determinants of Arterial Remodeling in Atherogenesis

描述（由申请人提供）：人冠状动脉粥样硬化中的活化细胞表达高水平的基质降解酶，如胶原酶和弹性酶。我们以前的研究表明，这种胶原溶解和弹性溶解活动调节病变动脉的完整性。最近一系列由NIH R01支持的研究为基质金属蛋白酶（MMP）家族的胶原溶解酶在动脉重塑中的重要作用提供了直接的体内证据。本研究旨在进一步研究胶原酶的遗传和药理学调控对斑块胶原代谢的影响，并深入研究弹性分解酶在动脉疾病中的作用。我们还将探索利用生物标志物检测基质降解的可能性。Specific Aim 1将完成我们对各种间质胶原酶在调节小鼠动脉粥样硬化斑块结构中的作用的研究。我们将研究另一种胶原酶MMP-8缺乏对斑块结构的影响。我们将进一步分析缺乏两种主要胶原酶MMP-13和MMP-8的复合突变小鼠动脉粥样硬化中的胶原结构。使用一种新的成像技术和一种MMP-13选择性抑制剂的研究将验证这种胶原酶的药物抑制会改变斑块结构的假设。特异性目标2将验证apoE和尼曼匹克病C1型（NPC1）蛋白联合缺乏的小鼠对动脉扩张的易感性增加的假设。由于复合突变的apoE-和npc1缺陷小鼠过度表达组织蛋白酶K，这是一种有效的弹性酶，我们将通过分子成像来追踪这些动物体内组织蛋白酶的活性。我们还将成像和表征这些操纵突变小鼠动脉组织中弹性蛋白的结构。Specific Aim 3将开发和验证细胞外基质蛋白降解的生物标志物，为探索体内弹性蛋白和胶原蛋白降解提供新的工具。这些标记将包括MSGC测量翻译后修饰的氨基酸及其凝聚物，作为弹性蛋白和胶原蛋白分解的标志。探索弹性蛋白溶解新标志物的体内效用将使用来自多种弹性酶突变小鼠的生物标本，包括组织蛋白酶K和S， MMP-9和-12，中性粒细胞弹性酶，以及遗传诱导的心肌病小鼠。如果我们成功地开发和验证了新的生物标志物，我们将把它们应用于在我们机构进行的各种大型临床试验中患者的血液标本库，以测试干预措施（例如矿化皮质激素受体阻滞剂或他汀类药物管理）影响人体体内基质代谢的假设。

DESCRIPTION (provided by applicant): Activated cells in human coronary atheromata express high levels of matrix-degrading enzymes, e.g., collagenases and elastases. Our previous studies suggested that such collagenolytic and elastolytic activities regulate the integrity of diseased arteries. A series of recent studies supported by this NIH R01 provided the direct in vivo evidence for the important role of collagenolytic enzymes of the matrix metalloproteinase (MMP) family in arterial remodeling. This renewal application proposes to examine further the effects of genetic and pharmacologic manipulations of collagenases on plaque collagen metabolism, and to study in depth the role of elastolytic enzymes in arterial disease. We will also explore the possibility of detecting matrix degradation using biomarkers. Specific Aim 1 will complete our studies of the roles of various interstitial collagenases in the regulation of the structure of atherosclerotic plaques in mice. We will examine the effects of deficiency of another collagenase MMP-8 on plaque structure. We will further analyze collagen structure in atheromata of the compound mutant mice lacking two major collagenases MMP-13 and MMP-8. Studies using a novel imaging technology and an MMP-13 selective inhibitor will test the hypothesis that pharmacologic inhibition of this collagenase will alter the plaque structure. Specific Aim 2 will test the hypothesis that mice with combined deficiency of apoE and Niemann Pick disease, type C1 (NPC1) protein will show heightened susceptibility to arterial ectasia. As compound mutant apoE- and NPC1-deficient mice overexpress cathepsin K, a potent elastase, we will track cathepsin activity in vivo in these animals by molecular imaging. We will also image and characterize the structure of elastin in arterial tissue from these manipulated mutant mice. Specific Aim 3 will develop and validate biomarkers of extracellular matrix protein degradation to provide novel tools to probe elastin and collagen degradation in vivo. These markers will include MSGC measurement of post-translationally modified amino acids and their condensates that serve as signatures for elastin and collagen breakdown. Exploration of the in vivo utility of novel markers of elastinolysis will use biological specimens derived from mice with mutations in various elastases including cathepsins K and S, MMP-9 and -12, and neutrophil elastase, as well as from mice with genetically-induced cardiomyopathies. If we succeed in developing and validating novel biomarkers, we will apply them to banks of blood specimens on patients in various large clinical trials conducted at our institution to test the hypothesis that the interventions (e.g. mineralocorticid receptor blocking agent or statin administration) affect matrix metabolism in humans in vivo. PUBLIC HEALTH RELEVANCE: Collagenolytic and elastolytic activities in human coronary atheromata likely regulate the matrix structure of atherosclerotic plaques, a key determinant of the acute thrombotic complications. Our recent studies supported by this NIH R01 provided the direct in vivo evidence for the important role of collagenolytic enzymes. This renewal application proposes to examine further the effects of pharmacologic and genetic manipulations of collagenases on plaque collagen metabolism. We also propose to study in depth the role of elastolytic enzymes in the pathogenesis of arterial disease. In addition, we will explore the possibility of detecting matrix degradation using biomarkers. This project should help in understanding the mechanisms of arterial remodeling during atherogenesis. These complementary studies will translate further preclinical findings into clinical preventive cardiovascular medicine.