HDL MEDIATED CHOLESTEROL CLEARANCE FROM FOAM CELLS

HDL被认为参与胆固醇的逆向转运， 从外周组织和动脉粥样硬化病变中去除胆固醇 并将其处置到肝脏。 我们的动脉粥样硬化模型 使用转化的人单核细胞白血病细胞系， THP-1单核细胞，其呈现巨噬细胞形态和功能， 接触佛波醇酯。 研究表明HDL介导的胆固醇 去除受细胞信号转导的变化调节。 的时间 HDL清除细胞内胆固醇的过程表明， 脂蛋白可影响蛋白质合成和基因转录。 我们的初步结果表明，THP-1巨噬细胞可以积累 当暴露于乙酰化LDL（acLDL）时， 不含油酸。 本研究项目的具体目标是（1） 为了优化THP-1中泡沫泡孔形成的条件， 巨噬细胞; EC积聚将通过质量和掺入来测量 放射性标记的脂肪酸转化为EC。(2)为了研究细胞的作用 高密度脂蛋白介导THP-1泡沫清除胆固醇的信号转导 细胞;测量cAMP、腺苷酸环化酶 活性，G蛋白活化，蛋白激酶A活性，蛋白激酶 C活性、二酰甘油和磷酸肌醇在细胞中的积累 暴露于对照培养基和含有HDL的培养基。(3)以确定是否 HDL介导的胆固醇清除与基因改变有关 表达和蛋白质合成;新合成基因的出现 将使用二维凝胶电泳技术测量产物 和差异噬斑过滤杂交。 这些研究的结果将有助于阐明 HDL介导的人巨噬泡沫细胞胆固醇清除。 医师科学家奖将允许主要研究者 发展细胞和分子生物学原理的专业知识， 一个非常适合这种奋进的环境。

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.