Oxidant resistant apoA1 in reverse cholesterol transport, inflammation and atherosclerosis

摘要 高密度脂蛋白胆固醇（HDL-C）水平与心血管疾病风险降低有关。 疾病（CVD）的流行病学研究。尽管有几种机制可能在HDL的保护作用中起作用， HDL及其主要蛋白质成分载脂蛋白-AI（apoA 1）是逆转的关键成分。 胆固醇转运（RCT）途径，其中胆固醇从外周组织中去除并转移到 肝脏进行排泄在RCT途径的第一步中，贫脂apoA 1作为细胞的受体， 胆固醇和磷脂通过细胞膜蛋白ABCA 1，产生新生HDL。但并非 所有的HDL都是等效的，一些研究报告说，患有冠状动脉疾病的人 高密度脂蛋白是“功能失调”，不再动脉粥样硬化保护。动脉粥样硬化病变是一种高度氧化的 环境和人体病变含有高水平的抗微生物酶髓过氧化物酶（MPO）， 我们和其他人已经证明它可以氧化apoA 1并削弱其功能。我们确定这四个人 人apoA 1（h-apoA 1）中的色氨酸残基在其MPO介导的胆固醇受体丢失中是至关重要的 功能我们创造了一种新的4 WF h-apoA 1变体，其中所有四个色氨酸残基都被替换为 苯丙氨酸，其对MPO介导的功能丧失具有抗性。我们创造并鉴定了转基因 表达高水平4 WF h-apoA 1同种型的小鼠，发现这些小鼠对 炎症我们还建立了人MPO转基因小鼠，其过表达MPO，可以进一步 酵母多糖处理诱导。在这里，我们建议在小鼠模型中表征h-apoA 1修饰， 如果这些受到炎症刺激的调节。我们还将测试抗氧化剂4 WF apoA 1 异构体可以更好地保护免受炎症和脓毒症，促进胆固醇逆向转运，延缓 动脉粥样硬化进展，并促进动脉粥样硬化消退的小鼠，过表达MPO， 一种类似于人体病变的氧化环境。从机制上讲，我们将确定如何 4 WF同种型保护小鼠免受急性期反应，并检查4 WF同种型是否能更好地预防 骨髓细胞增殖和从骨髓动员导致单核细胞增多和嗜中性粒细胞增多， 与动脉粥样硬化进展有关。

Abstract High levels of high density lipoprotein-cholesterol (HDL-C) are associated with lowered risk for cardiovascular disease (CVD) in epidemiological studies. Although several mechanisms may play a role in HDL’s protective effect, HDL and its major protein constituent, apolipoprotein-AI (apoA1), are critical components of the reverse cholesterol transport (RCT) pathway, in which cholesterol is removed from peripheral tissues and transferred to the liver for excretion. In the first step of the RCT pathway, lipid-poor apoA1 acts as an acceptor for cell cholesterol and phospholipids via the cell membrane protein ABCA1, generating nascent HDL. However, not all HDL is equivalent, and several studies have reported that individuals with coronary artery disease have HDL that is “dysfunctional” and no longer atheroprotective. The atherosclerotic lesion is a highly oxidative environment, and human lesions contain high levels of the antimicrobial enzyme myeloperoxidase (MPO), which we and others have shown can oxidize apoA1 and impair its function. We determined that the four tryptophan residues in human apoA1 (h-apoA1) are crucial in its MPO mediated loss of cholesterol acceptor function. We created a novel 4WF h-apoA1 variant, in which all four tryptophan residues are replaced by phenylalanine, which is resistant to MPO-mediated loss of function. We created and characterized transgenic mice that express high levels of the 4WF h-apoA1 isoform and found that these mice were resistant to inflammation. We also created human MPO transgenic mice, which over express MPO that can be further induced by zymosan treatment. Here we propose to characterize h-apoA1 modifications in mouse models and if these are modulated by inflammatory stimuli. We will also test whether the oxidant resistant 4WF apoA1 isoform can better protect from inflammation and sepsis, promote reverse cholesterol transport, delay atherosclerosis progression, and promote atherosclerosis regression in mice that over express MPO, creating an oxidative environment similar to that found in human lesions. Mechanistically, we will determine how the 4WF isoform protects mice from an acute phase response, and examine if the 4WF isoform better prevents myeloid cell proliferation and mobilization from the bone marrow leading to monocytosis and neutrophilia that are associated with atherosclerosis progression.