Role of MMPs in arterial calcification

项目摘要/摘要 动脉钙化越来越多地与各种患者的不良预后有关 人群包括患有冠状动脉、主动脉和外周动脉疾病的患者以及 糖尿病和肾衰竭。我们先前证明，外周动脉的钙化预示着 即使在调整了人口统计学、心血管危险因素和踝臂指数后也是截肢。 在动脉钙化过程中，中膜平滑肌细胞(SMCs)发生成骨转化并丢失 最常见的表型特异性标记和因子和信号分子的新表达 发育中的骨骼。我们和其他人已经确定了基质金属蛋白酶(MMPs)在 动脉钙化的进展。基质金属蛋白酶在钙化的动脉中高度表达，我们有 证明了用广谱和合成抑制剂降低它们的活性可以防止实验 体外和体内的钙化。在目前提案的初步数据中，我们表明，基质金属蛋白酶-3 基质分解素-1是钙化鼠主动脉中诱导作用最强的一种金属蛋白酶。减少 基质金属蛋白酶-3活性减少培养的人和啮齿动物血管内皮细胞和大鼠主动脉器官中的钙蓄积 文化模式。在器官培养和培养中，来自基质金属蛋白酶-3缺陷的小鼠的主动脉不受中层钙化的保护 活着。此外，我们最近表明，基质金属蛋白酶-3可以降低ENPP1的水平，从而产生抗- 来自三磷酸腺苷的钙化焦磷酸(PPI)。钙化所需的基质金属蛋白酶-3活性的位置 局部性或系统性，其对SMC转型的贡献目前尚不清楚，这可能会起到 开发用于临床试验的合适的抑制剂的障碍。根据我们和其他人的数据， 我们提出了最重要的假设，即基质金属蛋白酶-3通过促进内侧动脉钙化 血管平滑肌细胞的转化和改变循环中刺激因子和抑制因子的平衡。减少 基质金属蛋白酶-3的活性将减缓患者动脉钙化的进展。当我们检验这一假设时，我们将1) 阐明基质金属蛋白酶-3在磷酸盐诱导的SMC转化中的作用并确定其是否具有作用 通过降解ENPP1促进钙化。2)。确定基质金属蛋白酶-3是否促进体内动脉钙化 通过对内侧SMC的局部作用或通过改变循环中的刺激因子和抑制因子的平衡，以及3) 用多西环素抑制基质金属蛋白酶活性能否预防外周动脉病变进展 临床试验中的钙化。在实现这些目标的过程中，我们将回答有关 基质金属蛋白酶在动脉钙化中的作用及专门临床试验评估基质金属蛋白酶抑制作用的可能性 旨在减少钙化和改善我们的动脉疾病患者预后的战略。

Project summary/abstract Arterial calcification has increasingly been associated with poor outcomes in a wide variety of patient populations including those with coronary, aortic, and peripheral artery disease, as well as patients with diabetes, and renal failure. We previously demonstrated that calcification in peripheral arteries predicts major amputation even after adjusting for demographics, cardiovascular risk factors, and the ankle brachial index. During arterial calcification, medial smooth muscle cells (SMCs) undergo osteogenic transformation with loss of phenotype-specific markers and new expression of factors and signaling molecules most commonly found in developing bone. We and others have established a critical role for matrix metalloproteinases (MMPs) in the progression of arterial calcification. MMPs are highly expressed in calcifying arteries, and we have demonstrated that reducing their activity with broad spectrum and synthetic inhibitors can prevent experimental calcification both in vitro and in vivo. In preliminary data for the current proposal, we show that MMP-3 (stromelysin-1) is the most strongly induced of all metalloproteinases in calcifying rodent aortas. Reducing MMP-3 activity decreases calcium accumulation in cultured human and rodent SMCs and in a rat aorta organ culture model. Aortas from MMP-3-deficient mice are protected from medial calcification in organ culture and in vivo. Additionally, we have recently shown that MMP-3 can decrease levels of ENPP1 that generates anti- calcifying pyrophosphate (PPi) from ATP. The location of MMP-3 activity required for calcification, whether local or systemic, and its contribution to SMC transformation is not currently known and this may act as a barrier to development of appropriate inhibitors for use in clinical trials. Based on our data and those of others, we propose the overarching hypothesis that MMP-3 contributes to medial artery calcification by promoting transformation of vascular SMCs and altering the balance of circulating stimulators and inhibitors. Reducing MMP-3 activity will slow the progression of arterial calcification in patients. As we test this hypothesis we will 1) delineate the contribution of MMP-3 to phosphate-induced SMC transformation and determine whether it can promote calcification by degrading ENPP1. 2). Determine whether MMP-3 promotes in vivo arterial calcification through local actions on medial SMCs or by altering the balance of circulating stimulators and inhibitors, and 3) Determine whether inhibiting MMP activity with doxycycline can prevent progression of peripheral artery calcification in a clinical trial. As we progress through these aims we will answer critical questions about the role of MMPs in arterial calcification and the potential for a dedicated clinical trial to assess the MMP inhibition strategies aimed at reducing calcification and improving outcomes in our patients with arterial disease.