MMP-9 Activity Mediates Vascular Effects of Inhaled Environmental Air Pollutants

动脉粥样硬化是一种与动脉斑块形成相关的炎症性疾病，是全球发病率和死亡率的主要原因。斑块破裂通常会导致中风或急性心肌梗死(AMI)等临床结果。大量的流行病学证据表明，颗粒物和气态空气污染物与心血管事件发生率的增加有关，但所涉及的细胞通路尚未阐明。动脉细胞外基质(ECM)重塑是动脉粥样硬化进展过程中的关键步骤，其主要受基质金属蛋白酶(MMPs)活性的调节。我们已经报道了与汽车尾气暴露相关的血管基质金属蛋白酶-9升高，但在该模型中对基质金属蛋白酶-9的调节尚未阐明。该方案的目的是验证一种假设，即暴露于普遍存在的环境空气污染物--汽车尾气(VEE)中，会导致氧化脂蛋白(OxLDL)介导的内皮素-1(ET-1)诱导，并通过ET-1-ETA丝裂原激活蛋白激酶(MAPK)信号通路激活血管和循环中的基质金属蛋白酶-9(MAPK)。对于提议的实验，我们将利用易患动脉粥样硬化的载脂蛋白E基因敲除小鼠。在目标1中，我们将分别通过使用ET-1受体拮抗剂(BQ-123)和MMPinihibitor，来研究参与ET-1介导的血管MMP9表达的分子通路，以及VEE暴露后MMPTIMPs的调节。由此产生的MAPK通路ERK1/2、p38和JNK的表达将被分析。在目标2中，我们将确定VEE是否导致BQ-123治疗后冠状动脉和脑血管中ET-1和MMP-9的升高。 分析MMP9和TIMP的表达及细胞定位。在目标3中，我们。我们将通过凝集素样氧化低密度脂蛋白受体(LOX-1)阐明oxLDL信号在调节ET-1和MMP9的诱导中的作用。在目标4中，我们将确定暴露于常见环境空气污染物(VEE、混合汽油和柴油废气)是否会导致循环生物标志物--基质金属蛋白酶-S和可溶性LOX-1在小鼠和人类样本中的表达。：

Atherosclerosis, an Inflamniatory disease associated with the production of arterial plaques, is the leading cause of morbidity and mortality worldwide. Plaque rupture commonly leads to clinical outcomes such as stroke or acute myocardial infarction (AMI). Substantial epidemiological evidence indicates that particulate and gaseous air pollutants are associated with increased rates of cardiovascular incidents, however the cellular pathways involved have not yet been elucidated. Remodeling of arterial extracellular matrix (ECM) is a crucial step in the progression of atherosclerosis, which is primarily regulated through matrix metalloproteinase (MMP) activity. We have reported elevated vascular MMP-9 associated with inhaiational exposure to vehicular exhaust, however regulation of MMP-9 in this model has not been elucidated. The goal of this proposal is to test the hypothesis that exposure to the ubiquitous environmental air pollutant, vehicular engiiie emissions (VEE), results in oxidized lipoprotein (oxLDL)-mediated induction of endothelin-1 (ET-1) and activation of vascular and circulating MMP-9 through an ET-1 - ETA mitogen activated protein kinase (MAPK) signaling pathway. For the experiments proposed, we will utilize atherosclerosis-prone ApoE knockout mice. In Aim 1, we will investigate Ihe molecular pathways involved in ET-1-mediated expression of vascular MMP-9, and regulation of MMP tissue inhibitors (TIMPs), following exposure to VEE, through use of an ET-1 receptor antagonist (BQ-123) and a MMP inihibitor, respectively. Resulting MAPK pathway ERK1/2, p38, and JNK expression will be analyzed. In Aim 2, we wili detennine whether VEE results in elevated ET-1 and MMP-9 in the coronary and cerebrovasculature with BQ-123 treatment. MMP-9 and TIMP expression, and cellular localization will be analyzed. In Aim 3, we. will elucidate the role of oxLDL signaling, via lectin-like oxLDL receptor (LOX-1), in regulating induction .of ET-1 and MMP9, in response to exposure to VEE by anti-LOX-1 antibody expression knockdown^ In Aim 4, we will deterrnine whether exposure to common environmental air pollutants (VEE,: mixed gasolinerand diesel exhaust) results in expression of circulating biomarkers, MMP-S and soluble LOX-1, in murine and-human samples. :