Macrophage-Derived Oxidants in Atherogenesis

动脉粥样硬化中巨噬细胞衍生的氧化剂

• 批准号: 7107291
• 负责人: JAY W HEINECKE
• 金额: $ 37.98万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7107291
• 关键词: NAD(P)H dehydrogenase; atherosclerotic plaque; clinical research; enzyme activity; enzyme mechanism; extracellular matrix proteins; free radicals; genetically modified animals; human tissue; laboratory mouse; macrophage; metalloendopeptidases; monokines; myeloperoxidase; oxidizing agents; proteolysis

DESCRIPTION (provided by applicant): Rupture of atherosclerotic lesions is a major trigger for myocardial infarction and sudden death. One important mechanism is likely to be activation of matrix metalloproteinases (MMPs), which destroy matrix components in vitro and in atherosclerotic models in vivo. MMPs also play a critical role in regulating cell migration, the recruitment of inflammatory cells, and the immune response. Multiple lines of evidence suggest that oxidants produced by the phagocyte NADPH oxidase and reactive nitrogen species both activate and inactivate MMPs in vitro. These observations indicate that oxidation may regulate the progression of atherosclerotic lesions by a variety of mechanisms. We have shown that oxidants produced by macrophages markedly activate pro-MMP-7 by converting the thiol residue of the cysteine switch to sulfinic acid. This activation mechanism is distinct from the well studied proteolytic cleavage of MMP pro-enzymes. Failure to inhibit MMP activity might also play a role in tissue destruction under inflammatory conditions. We have shown that higher concentrations of oxidants inhibit the activity of human MMP-7 in vitro, suggesting that it might limit proteolytic activity during inflammation. Our findings suggest that local, pericellular production of oxidants by phagocytes is a physiological mechanism for restraining MMP activity during inflammation. We propose to test the hypothesis that oxidants generated by macrophages in the artery wall play a critical role in regulating MMPs, matrix degradation, and lesion progression during the pathogenesis of atherosclerosis. Our specific aims are: First, to establish the molecular mechanisms by which the NADPH oxidase pathway, the myeloperoxidase pathway and the reactive nitrogen pathway both activate and inactivate MMPs in vitro. Second, to use macrophages isolated from mice deficient in MMPs or oxidant generating pathways to investigate the mechanisms for regulation of proteolysis during atherogenesis. Third, to investigate cellular mechanisms for regulating proteolysis in the artery wall, using mice deficient in pathways that generate oxidants. Fourth, to determine whether human atherosclerotic tissue contain oxidized prodomains of MMPs implicated in proteolytic activation. Collectively, the proposed experiments will address the role of macrophage-derived oxidants in regulating MMP activity during atherogenesis.

描述（由申请人提供）：动脉粥样硬化病变的破裂是心肌梗塞和猝死的主要触发因素。一种重要的机制可能是基质金属蛋白酶（MMP）的激活，它会破坏体外和体内动脉粥样硬化模型中的基质成分。 MMP 在调节细胞迁移、炎症细胞招募和免疫反应方面也发挥着关键作用。多种证据表明，吞噬细胞 NADPH 氧化酶和活性氮产生的氧化剂均可在体外激活和灭活 MMP。这些观察结果表明氧化可能通过多种机制调节动脉粥样硬化病变的进展。我们已经证明，巨噬细胞产生的氧化剂通过将半胱氨酸开关的硫醇残基转化为亚磺酸，显着激活 MMP-7 前体。这种激活机制与经过充分研究的 MMP 酶原的蛋白水解裂解不同。未能抑制 MMP 活性也可能在炎症条件下的组织破坏中发挥作用。我们已经证明，较高浓度的氧化剂会在体外抑制人 MMP-7 的活性，这表明它可能会限制炎症期间的蛋白水解活性。我们的研究结果表明，吞噬细胞在细胞周局部产生氧化剂是炎症期间抑制 MMP 活性的生理机制。我们建议检验动脉壁巨噬细胞产生的氧化剂在动脉粥样硬化发病过程中调节 MMP、基质降解和病变进展中发挥关键作用的假设。我们的具体目标是：首先，建立NADPH氧化酶途径、髓过氧化物酶途径和活性氮途径在体外激活和灭活MMP的分子机制。其次，利用从缺乏 MMP 或氧化剂生成途径的小鼠中分离出的巨噬细胞来研究动脉粥样硬化形成过程中蛋白水解的调节机制。第三，使用缺乏产生氧化剂的途径的小鼠来研究调节动脉壁蛋白水解的细胞机制。第四，确定人动脉粥样硬化组织是否含有参与蛋白水解激活的 MMP 氧化前结构域。总的来说，拟议的实验将解决巨噬细胞衍生的氧化剂在动脉粥样硬化形成过程中调节 MMP 活性的作用。