HDL MEDIATED CHOLESTEROL CLEARANCE FROM FOAM CELLS

高密度脂蛋白被认为通过以下途径参与胆固醇的反向运输 清除外周组织和动脉粥样硬化病变中的胆固醇 并将其直接处理到肝脏。我们的动脉粥样硬化模型 利用转化的人单核细胞白血病细胞系， THP-1单核细胞，具有巨噬细胞的形态和功能 接触佛波酯。研究表明，高密度脂蛋白介导的胆固醇 细胞信号转导的变化对细胞的去除起着调节作用。时间 高密度脂蛋白清除细胞内胆固醇的过程表明 脂蛋白可能影响蛋白质合成和基因转录。 我们的初步结果表明，THP-1巨噬细胞可以积聚 与乙酰化低密度脂蛋白(AcLDL)接触时的酯化胆固醇(EC) 而且不含油酸盐。本研究项目的具体目标是：(1) 优化THP-1中泡沫细胞的形成条件 巨噬细胞；EC的积聚将通过质量和掺入来测量 放射性标记脂肪酸进入EC。(2)研究细胞的作用 高密度脂蛋白介导的THP-1泡沫中胆固醇清除的信号转导 细胞；将对cAMP、腺苷环化酶进行测量 活性、G蛋白激活、蛋白激酶A活性、蛋白激酶 C活性、二酰甘油和肌醇磷酸在细胞中的积累 暴露于对照介质和含高密度脂蛋白的介质中。(3)确定是否 高密度脂蛋白介导的胆固醇清除与基因改变相关 表达和蛋白质合成；新合成基因的出现 产品将使用二维凝胶电泳法进行检测 和斑块差异滤器杂交。 这些研究的结果将有助于阐明(S)的发病机制 高密度脂蛋白介导的人巨噬细胞泡沫细胞中胆固醇的去除。 医师科学家奖将允许首席研究员 培养在细胞和分子生物学原理方面的专业知识 一个非常适合这一努力的环境。

HDL is thought to participate in reverse cholesterol transport by removing cholesterol from peripheral tissues and atherosclerotic lesions and directing its disposal to the liver. Our model of atherosclerosis employs use of the transformed human monocytic leukemic cell line, the THP-1 monocyte, which assumes macrophage morphology and function upon exposure to phorbol ester. Studies suggest that HDL-mediated cholesterol removal is modulated by changes in cell signal transduction. The time course for HDL removal of intracellular cholesterol suggests that the lipoprotein may effect protein synthesis and gene transcription. Our preliminary results indicate that THP-1 macrophages can accumulate esterified cholesterol (EC) when exposed to acetylated LDL (acLDL) with and without oleate. The specific aims of this research project are (1) To optimize the conditions for foam cell formation in the THP-1 macrophage; EC accumulation will be measured by mass and by incorporation of radiolabeled fatty acid into EC. (2) To investigate the role for cell signal transduction in HDL-mediated cholesterol clearance from THP-1 foam cells; Measurements will be performed for cAMP, adenylyl cyclase activity, G protein activation, protein kinase A activity, protein kinase C activity, diacylglycerol and inositol phosphate accumulation in cells exposed to control medium and that containing HDL. (3) To determine if HDL-mediated cholesterol clearance is associated with altered gene expression and protein synthesis; Appearance of newly synthesized gene products will be measured using the techniques of 2-D gel electrophoresis and differential plaque filter hybridization. Results from these studies will help to elucidate the mechanism(s) of HDL-mediated cholesterol removal from human macrophage foam cells. The Physician Scientist Award will allow the principal investigator to develop an expertise in the principles of cell and molecular biology in an environment well suited to this endeavor.