MACROPHAGE CHOLESTEROL EFFLUX IN ATHEROSCLEROSIS

动脉粥样硬化中的巨噬细胞胆固醇流出

• 批准号: 3368358
• 负责人: Richard W ST CLAIR
• 金额: $ 21.84万
• 依托单位: WAKE FOREST UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1997-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3368358
• 关键词: aorta; atherosclerosis; atherosclerotic plaque; bone marrow transplantation; cholesterol esters; disease /disorder proneness /risk; enzyme activity; family genetics; genetic models; genetic strain; laboratory mouse; laboratory rabbit; lipase; macrophage; molecular pathology; pigeons; polymerase chain reaction; radiotracer; tissue /cell culture; whole body irradiation effect

Atherosclerosis is a disease of multiple etiology that is influenced by a variety of risk factors. Risk factors, however, can explain only a portion of the variability in this disease. The remaining unexplained variability is due, at least in part, to genetic factors mediated at the level of the arterial wall. The proposed studies will address potential genetically-mediated arterial wall factors by utilizing breeds of pigeons that are genetically susceptible (White Carneau, WC) or resistant (Show Racer, SR) to aortic atherosclerosis. Macrophages play an important role in the pathogenesis of atherosclerosis in pigeons, as they do in man. Although both WC and SR macrophages accumulate large amounts of cholesteryl esters when incubated with certain abnormal lipoproteins, there is no difference in the amount of cholesteryl esters that accumulate in macrophages from the two breeds. SR macrophages in culture, however, are able to efflux this excess cholesterol efficiently to an appropriate acceptor in the medium while, under the same conditions, WC macrophages are defective in cholesterol efflux. The purpose of the proposed studies is to define the cellular and molecular mechanism(s) responsible for this defect in cholesterol efflux and to test the hypothesis that susceptibility to atherosclerosis in the WC pigeon is mediated by an abnormality in cholesterol homeostasis in their macrophages resulting from a defect in cholesterol efflux. Three specific aims are proposed to test this hypothesis. Specific Aim 1 will determine the cellular and molecular mechanisms responsible for the lower rate of cholesterol efflux from cultured WC macrophages. Unlike most published studies, these studies will use macrophages in culture that are loaded with cholesteryl esters to levels found in macrophage foam cells from atherosclerotic plaques. This is accomplished by loading elicited pigeon peritoneal macrophages in vitro with cholesteryl esters or using macrophages from hypercholesterolemic pigeons that are already loaded with cholesteryl esters. Using a variety of agents to stimulate or inhibit potential regulatory steps in cellular cholesterol homeostasis, the proposed studies will determine how cholesterol efflux is regulated in pigeon macrophage foam cells, and the site of the defect in cholesterol efflux in WC macrophages. Specific Aim 2 will determine the extent to which individual variability in aortic atherosclerosis in WC pigeons is correlated with the defect in their macrophages to efflux cholesterol (expt. 1), and if differences in cholesterol efflux potential from macrophages cultured in vitro can be used to predict the subsequent severity of development of atherosclerosis (expt. 2). Specific Aim 3 will test directly the hypothesis that this defect in WC macrophages is responsible for their enhanced atherosclerosis. This will be done by transplanting macrophages from SR pigeons into WC pigeons and vice versa, and studying its effect on the extent and severity of experimental atherosclerosis.

动脉粥样硬化是一种多种病因的疾病，其影响因素包括 各种风险因素。然而，风险因素只能解释 这种疾病的变异性的一部分。其余的未解释 变异至少在一定程度上是由于遗传因素在 动脉壁的水平。拟议的研究将涉及潜在的 利用不同品种鸽子遗传介导的动脉壁因子 在基因上易感(白卡诺，WC)或抗性(Show RACER，SR)到主动脉粥样硬化。巨噬细胞扮演着重要的角色 在鸽子动脉粥样硬化的发病机制中，就像他们在人类身上所做的那样。 尽管WC和SR巨噬细胞都积累了大量的 当胆固醇酯与某些异常脂蛋白孵育时， 在胆固醇酯的数量上没有区别 积聚在这两个品种的巨噬细胞中。巨噬细胞 然而，培养物能够有效地排出这种多余的胆固醇。 对媒体中的适当接受者，而在同一 在这种情况下，WC巨噬细胞在胆固醇外流方面存在缺陷。这个 拟议研究的目的是定义细胞和分子 这种胆固醇外流缺陷的机制(S)和 检验以下假设：WC对动脉粥样硬化的易感性 鸽子体内胆固醇稳态的异常是由其介导的 胆固醇外流缺陷引起的巨噬细胞。三 为了检验这一假说，本文提出了具体的目标。具体目标1将 确定导致低血压的细胞和分子机制 培养的WC巨噬细胞胆固醇流出速率。与大多数不同 已发表的研究，这些研究将在培养中使用巨噬细胞 胆固醇酯含量达到巨噬细胞泡沫细胞的水平 动脉粥样硬化斑块造成的。这是通过加载引发的 鸽子腹膜巨噬细胞体外胆固醇酯或使用 已负荷的高胆固醇血症鸽的巨噬细胞 含有胆固醇酯。使用各种试剂来刺激或 抑制细胞胆固醇动态平衡的潜在调控步骤， 拟议中的研究将确定胆固醇外流是如何调节的。 在鸽子巨噬细胞泡沫细胞中，缺陷的位置在 WC巨噬细胞的胆固醇外流。具体目标2将决定 WC患者动脉粥样硬化的个体变异性程度 鸽子的巨噬细胞外流缺陷与之相关 胆固醇(Ext.1)，如果胆固醇外流潜力的差异 从体外培养的巨噬细胞中可以预测后续的 动脉粥样硬化发展的严重程度(Ext.2)。具体目标3 将直接检验WC巨噬细胞中的这种缺陷是 对他们增强的动脉粥样硬化负责。这将通过以下方式完成 将SR鸽的巨噬细胞移植到WC鸽体内，反之亦然， 并研究其对实验性脑损伤程度和严重程度的影响。 动脉硬化。