CHOLESTEROL METABOLISM--ROLE OF APOA I

胆固醇代谢——APOA I 的作用

• 批准号: 6389646
• 负责人: DAVID LEE WILLIAMS
• 金额: $ 32.27万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2002-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6389646
• 关键词: adrenal glands; animal genetic material tag; apolipoproteins; blood lipoprotein metabolism; blood lipoprotein transport; chemical structure function; cholesterol esters; electron microscopy; gel filtration chromatography; genotype; high density lipoproteins; high performance liquid chromatography; laboratory mouse; light microscopy; low density lipoprotein; neoplastic cell culture for noncancer research; northern blottings; protein purification; protein structure function; receptor binding; receptor expression; steroid biosynthesis; transfection; western blottings

DESCRIPTION (Adapted from applicant's Abstract): The two aims of this proposal are focused on the lipoprotein cholesteryl ester (CE) selective uptake pathway. Selective uptake is a process in which CE is selectively transferred from lipoproteins into the cell without the uptake and degradation of the lipoprotein particle. This is a major pathway for the uptake of lipoprotein cholesteryl ester into steroidogenic tissues (about 90% in rodents) and may also play a significant role in the liver in reverse cholesterol transport. Although the selective uptake pathway has been known for some 15 years, there has been little success in determining the protein participants on the cell surface or the essential protein and lipid components on the lipoprotein particle. This proposal is based on two recent findings which now make it possible to evaluate important features of both the lipoprotein particle and a putative selective uptake receptor on the cell surface. The first finding is that steroidogenic tissues of apoA-I-deficient mice show an almost complete failure to accumulate cholesteryl ester, suggesting the hypothesis that apoA-I is essential for selective uptake of HDL-CE. This hypothesis will be tested by evaluating the ability of other apoproteins to substitute for apoA-I in vivo and by analyzing the selective uptake activities of apoA-I containing and apoA-I deficient HDL particles in cell culture. The second finding is that the recently cloned scavenger receptor B1 (SR-B1) can mediate selective uptake of HDL-CE when expressed in CHO cells. The hypothesis will be tested that this receptor is responsible for selective uptake of HDL-CE and LDL-CE into steroidogenic cells and the delivery of cholesterol for steroid production by expressing a transfected SR-B1 gene in adrenal cells. The SR-B1 expressing cells will be used to evaluate the apoprotein specificity for this process and to delineate domains of apoA-I that are important in native HDL particles. These studies will provide new and important information about a cellular process that is central to the normal functioning of steroidogenic cells and that contributes to the regulation of the plasma cholesterol concentration which is an important determinant of human health.

描述（改编自申请人的摘要）：这两个目的 建议专注于脂蛋白胆固醇酯（CE）选择性 吸收途径。 选择性摄取是CE选择性的过程 从脂蛋白转移到细胞中，没有吸收， 脂蛋白颗粒的降解。 这是 将脂蛋白胆固醇酯摄取到类固醇组织中（大约 啮齿动物的90％），也可能在肝脏中起重要作用 胆固醇运输。 尽管已知的选择性吸收途径已知 大约15年，在确定蛋白质方面几乎没有成功 细胞表面或必需蛋白质和脂质的参与者 脂蛋白颗粒上的成分。 该建议基于两个 最近的发现现在可以评估的重要特征 脂蛋白颗粒和推定的选择性吸收受体都 细胞表面。 第一个发现是 apoa-i缺乏小鼠几乎完全无法累积 胆固醇酯，表明apoa-i对 HDL-CE的选择性吸收。 该假设将通过评估 其他载脂蛋白在体内代替apoa-i的能力和 分析含有ApoA-I的选择性吸收活动和apoa-i 细胞培养中的HDL颗粒不足。 第二个发现是 最近克隆的清道夫受体B1（SR-B1）可以介导选择性吸收 在CHO细胞中表达时HDL-CE的of。 该假设将被检验 该受体负责选择性摄取HDL-CE和LDL-CE进入 类固醇细胞和用于类固醇的胆固醇的递送 通过表达肾上腺细胞中转染的SR-B1基因。 SR-B1 表达细胞将用于评估载脂蛋白的特异性 这个过程并描绘出在本地重要的apoa-i的域 HDL颗粒。 这些研究将提供新的重要信息 关于一个蜂窝过程，这对于正常功能的核心 类固醇生成细胞，这有助于血浆的调节 胆固醇浓度是人类健康的重要决定因素。