MECHANISMS AND PATHWAYS OF CELL CHOLESTEROL TRANSPORT

细胞胆固醇运输的机制和途径

基本信息

批准号：
6043836
负责人：
ARMANDO J MENDEZ
金额：
$ 11.17万
依托单位：
UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
1996
资助国家：
美国
起止时间：
1996-08-01 至 2001-07-31
项目状态：
已结题

项目摘要

Atherosclerosis remains one of the major causes of morbidity and mortality in the US. Epidemiologic studies have shown a clear relationship between serum cholesterol levels and development and progression of atherosclerosis. As a result, major efforts have been instituted to reduce the serum cholesterol of individuals at risk, through lifestyle changes or drug therapies. Presumably, if reduction of serum cholesterol is to produce a reduction in existing atherosclerotic lesions an important mechanism would be to enhance removal of cholesterol from sites of accumulation, however, such mechanisms remain poorly understood. The long term goal of this proposal is to identify specific transport pathways involved in HDL mediated clearance of excess cholesterol from cells to gain further understanding of the processes involved in regression or formation of lipid laden foam cells as occur in atherosclerosis. We hypothesize that clearance of excess cellular cholesterol is an active process depending on stimulation by appropriate extracellular cholesterol acceptors that promote intracellular cholesterol transport to sites available for removal. This project aims to show that efflux of intracellular cholesterol requires an apolipoprotein dependent pathway mediated by active cellular processes distinct from non-specific aqueous diffusion of cholesterol and define cellular mechanism that facilitate transport of cholesterol from intracellular sites to sites available for removal by extracellular cholesterol acceptors. Cultured cells will be the experimental model to study cholesterol efflux pathways. Advantage will be made of somatic cell mutants with known defects in vesicular transport. Cholesterol efflux will be measured by changes in cell cholesterol mass and radioactivity, and changes of activities regulated by cell cholesterol levels. We will compare various extracellular cholesterol acceptor types to establish the contribution of apolipoprotein independent and dependent pathways for efficient cholesterol removal and establish if a link exists between efflux of excess cholesterol and phospholipids by the apolipoprotein dependent pathway. We will characterize cellular cholesterol transport pathways involving the Golgi apparatus and identify the contribution of proteins known to regulate vesicular transport. These studies will aid in delineating the cellular pathways involved in cholesterol transport through and out of the cell. Understanding these mechanisms will give greater knowledge of the atherosclerotic process and HDL function, and will lend insights into potential targets for pharmacological interventions to reduce the cholesterol contents of cells.

动脉粥样硬化仍然是发病和死亡的主要原因之一在美国。流行病学研究表明，两者之间存在明确的关系血清胆固醇水平与疾病的发生和进展动脉粥样硬化。因此，已做出重大努力通过生活方式降低高危人群的血清胆固醇改变或药物治疗。据推测，如果血清胆固醇降低是减少现有动脉粥样硬化病变的一个重要因素机制是增强从部位的胆固醇去除然而，人们对这种积累机制仍知之甚少。长的该提案的长期目标是确定具体的运输路径参与 HDL 介导的细胞内多余胆固醇清除进一步了解回归或相关过程动脉粥样硬化中发生的充满脂质的泡沫细胞的形成。我们假设清除多余的细胞胆固醇是一种积极的过程取决于适当的细胞外胆固醇的刺激促进细胞内胆固醇转运至位点的受体可供移除。该项目旨在表明细胞内胆固醇需要载脂蛋白依赖性途径由不同于非特异性水性的活性细胞过程介导胆固醇的扩散并定义促进的细胞机制将胆固醇从细胞内转运至可利用的部位通过细胞外胆固醇受体去除。培养的细胞将研究胆固醇流出途径的实验模型。优势将由具有已知囊泡缺陷的体细胞突变体制成运输。胆固醇流出将通过细胞的变化来测量胆固醇质量和放射性，以及受其调节的活性变化细胞胆固醇水平。我们将比较各种细胞外胆固醇受体类型以确定载脂蛋白的贡献有效去除胆固醇的独立和依赖途径确定过量胆固醇的外流与通过载脂蛋白依赖性途径产生磷脂。我们将表征涉及高尔基体的细胞胆固醇转运途径装置并确定已知调节蛋白质的贡献囊泡运输。这些研究将有助于描绘细胞参与胆固醇转运进出细胞的途径。了解这些机制将有助于我们更深入地了解动脉粥样硬化过程和 HDL 功能，并将有助于深入了解药物干预的潜在目标，以减少细胞内胆固醇含量。