OXYSTEROL REGULATION OF CHOLESTEROL METABOLISM

氧固醇对胆固醇代谢的调节

• 批准号: 2229207
• 负责人: THOMAS A SPENCER
• 金额: $ 28.08万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-07-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2229207
• 关键词: HMG coA reductases; binding proteins; cholesterol; cytoplasm; dietary lipid; enzyme activity; high performance liquid chromatography; hormone regulation /control mechanism; hydroxycholesterols; laboratory rat; lipid biosynthesis; lipid metabolism; mevalonate; nucleoproteins; nutrition related tag; oxidation; protein purification

The long range objective of the proposed research is to gain a complete understanding of the role of oxygenated sterols (oxysterols) in the complex mechanisms by which cholesterol metabolism is regulated. Two key unresolved aspects of the putative participation of oxysterols in this important area of biomedical research will be investigated. First, the role of oxysterols will be more precisely defined by correlating both their positive and negative effects in different cellular compartments with changes in activities of key enzymes of cholesterol metabolism as a function of time. This will be accomplished by studies of the effects of a cholesterol-enriched diet, and cessation thereof, on the concentrations of oxysterols in rat liver subcellular fractions in relation to the corollary effects on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a rate limiting enzyme of cholesterol synthesis, as an index for negative response, and on cholesterol 7 alpha-hydroxylase, the rate limiting enzyme of bile acid synthesis, as an index for positive response. In addition, the effects of mevalonic acid, as a precursor of sterols and oxysterols in vivo, on these same factors, will be investigated. Second, the hypothesis will be explored that oxysterols, specifically those identified as potential signal molecules in rat liver, are associated with specific proteins in 1) the cytosol, and 2) the nucleus, by identifying endogenously bound oxysterols in protein fractions separated by isoelectric focusing. Any putative receptor proteins thus identified will be isolated, purified, and characterized. Initial exploration of the possible significance of the fact that a major portion of the intracellular oxysterols exist in esterified form also will be conducted. All of these planned experiments have as their fundamental goal a better understanding of the centrally important issue of how cholesterol metabolism is regulated. Such understanding will contribute to achieving the ability either to prevent or reverse atherosclerosis. In addition, detailed knowledge of how cholesterol metabolism is regulated will be important in efforts to prevent or control other pathological conditions, such as cholesterol gallstone disease or malignancies.

拟议研究的远距离目标是获得完整的 了解氧化固醇（氧甲醇）在 调节胆固醇代谢的复杂机制。两个键 氧甲醇推定参与的未解决方面 将研究生物医学研究的重要领域。首先， 氧甲醇的作用将通过两者相关性来精确定义 它们在不同的细胞室中的积极和负面影响 随着胆固醇代谢的关键酶的活性变化 时间的功能。这将通过研究 富含胆固醇的饮食及其限制的浓度 与大鼠肝脏亚细胞级分的氧蛋白酶相对于 对3-羟基-3-甲基戊二酰辅酶A（HMG-COA）的推论作用 还原酶，胆固醇合成的速率限制酶，作为指数 对于负反应，以及胆固醇7α-羟化酶的速率 限制胆汁酸合成的酶，作为阳性反应的指数。 另外，甲酸甲酯的作用，作为固醇的前体和 将研究在这些相同因素上的体内氧化酚。第二， 将探讨该假设是氧甲醇，特别是这些假设 大鼠肝脏中被识别为潜在信号分子，与 1）细胞质中的特定蛋白质和2）核，通过识别核 蛋白质级分的内源性氧甲醇分开 等电聚焦。因此确定的任何推定的受体蛋白将 被隔离，纯化和表征。最初的探索 这一事实的重要性是 还将以酯化形式存在细胞内氧甲醇。 所有这些计划的实验都具有更好的基本目标 理解胆固醇如何中心重要的问题 代谢受到调节。这种理解将有助于实现 预防或逆转动脉粥样硬化的能力。此外， 详细了解如何调节胆固醇代谢 对于预防或控制其他病理状况的努力很重要， 例如胆固醇胆结石疾病或恶性肿瘤。