MACROPHAGE CHOLESTEROL EFFLUX IN ATHEROSCLEROSIS

动脉粥样硬化中的巨噬细胞胆固醇流出

基本信息

批准号：
2028803
负责人：
Richard W ST CLAIR
金额：
$ 25.4万
依托单位：
WAKE FOREST UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1993
资助国家：
美国
起止时间：
1993-01-01 至 1999-01-31
项目状态：
已结题

项目摘要

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病因性疾病，受以下因素影响各种危险因素。然而，风险因素只能解释这种疾病的变异性的一部分。剩下的无法解释变异性至少部分是由于遗传因素介导的动脉壁的水平。拟议的研究将解决潜在的问题利用鸽子品种遗传介导的动脉壁因子遗传上易感（White Carneau，WC）或耐药（Show Racer，SR）到主动脉粥样硬化。巨噬细胞发挥重要作用鸽子动脉粥样硬化的发病机制与人类一样。尽管 WC 和 SR 巨噬细胞都积累了大量的与某些异常脂蛋白一起孵育时产生胆固醇酯，胆固醇酯的含量没有差异在两个品种的巨噬细胞中积累。 SR巨噬细胞然而，培养物能够有效地排出多余的胆固醇到介质中适当的受体，同时在相同的条件下在这种情况下，WC巨噬细胞在胆固醇流出方面存在缺陷。这拟议研究的目的是定义细胞和分子造成胆固醇流出缺陷的机制检验 WC 中动脉粥样硬化易感性的假设鸽子的胆固醇稳态异常介导由于胆固醇流出缺陷而产生的巨噬细胞。三提出了具体目标来检验这一假设。具体目标 1 将确定负责较低的细胞和分子机制培养的WC巨噬细胞的胆固醇流出率。与大多数人不同已发表的研究，这些研究将使用培养物中的巨噬细胞胆固醇酯含量达到巨噬细胞泡沫细胞中的水平来自动脉粥样硬化斑块。这是通过加载引发的来完成的鸽子腹膜巨噬细胞体外与胆固醇酯或使用来自已经装载的高胆固醇血症鸽子的巨噬细胞与胆固醇酯。使用各种药剂来刺激或抑制细胞胆固醇稳态的潜在调节步骤，拟议的研究将确定如何调节胆固醇流出鸽子巨噬细胞泡沫细胞中的缺陷位置 WC 巨噬细胞中的胆固醇流出。具体目标 2 将确定 WC 中主动脉粥样硬化的个体差异程度鸽子的巨噬细胞流出缺陷与其相关胆固醇（实验 1），以及胆固醇流出潜力的差异体外培养的巨噬细胞可用于预测后续的动脉粥样硬化发展的严重程度（实验 2）。具体目标 3 将直接检验 WC 巨噬细胞中的这种缺陷是导致动脉粥样硬化加剧。这将由将 SR 鸽子的巨噬细胞移植到 WC 鸽子中，反之亦然，并研究其对实验的程度和严重程度的影响动脉粥样硬化。