NEURONAL MEMBRANE LIPID OXIDATION IN PARKINSONS DISEASE

帕金森病中的神经元膜脂质氧化

• 批准号: 2051757
• 负责人: GOVIND N.T. VATASSERY
• 金额: $ 14.28万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2051757
• 关键词: Parkinson's disease; age difference; cellular pathology; cholesterol; human subject; human tissue; laboratory rat; lipid metabolism; lipid peroxides; mitochondrial membrane; oxidation; oxidative stress; platelets; synaptosomes; tocopherols

This project is designed to test the hypothesis that specific areas of the brain such as substantia nigra and basal ganglia are especially vulnerable to oxidative stress and that their response to biochemical oxidative reactions (or oxidative stress) is defective in Parkinsons disease (PD) as well as in normal aging. Mitochondrial and synaptic membranes may lose their function due to inadequate response to oxidation an-or from direct damage induced by cytotoxic products of oxidation (e.g., cholesterol oxidation products). Levels of oxidation products and loss of function could be small under steady state conditions. Therefore, we will perturb the system by inducing oxidation of membranes in vitro (using primarily endogenous oxidants) in order to amplify existing differences. Our preliminary studies show that mitochondrial cholesterol is more oxidizable in PD than in controls. Mitochondrial and synaptosomal fractions will be oxidized by incubation with oxidizing agents (e.g., arachidonic and linoleic acid hydroperoxide plus metal ions like iron, mixtures of iron and ascorbic acid, nitric oxide with and without superoxide etc.). Different levels of oxidation of membranes can be defined by the extent of oxidation of two membrane lipids - tocopherol and cholesterol. Since the profile of cholesterol and tocopherol oxidation products would be characteristic for various types of oxidations, information on the mechanism of oxidation will be obtained. Synaptosomes and mitochondria from young and old rats, and PD and control human autopsy brain samples will be compared in all studies. Similar studies on oxidation of platelets (as an accessible model of neuronal membranes in humans) from PD and control subjects will be conducted. The extent of oxidation of membranes will be monitored and quantitated by determining the concentrations of tocopherol and cholesterol and their oxidation products as well as by estimating thiobarbituric acid reactive substances and the decline in total suIfhydryl concentrations. Oxidizing conditions which yield maximal differences between the control and experimental groups will be established first and then the cholesterol and tocopherol oxidation products will be isolated, identified, and quantitated by GC and GC-MS. A study of the effect of monoamine oxidase(MAO) on mitochondrial oxidation will be done by incubating mitochondria with dopamine, norepinephrine or serotonin (substrates for MAO) which releases in situ hydrogen peroxide and/or other oxidants derived from it. The oxidation will be followed and oxidation products characterized as with brain fraction& The effect of MAO inhibition by deprenyl upon the oxidation will also be studied. Number of similarities exist between the uptake of serotonin by platelets and brain. Serotonin uptake by platelets and synaptosomes at various levels of oxidation will be studied to examine the effect of oxidation upon membrane function. The data will be used to determine whether membrane damage induced by oxidative stress exists in PD and/or in normal aging. The data from the platelet studies may also provide a laboratory tool for the preclinical diagnosis of PD.

该项目旨在检验以下假设 大脑（例如黑质和基底神经节）特别容易受到伤害 氧化应激以及它们对生化氧化的反应 反应（或氧化应激）在帕金森氏病（PD）中有缺陷，因为 以及正常衰老。线粒体和突触膜可能会损失 它们的功能是由于直接对氧化AN-OR反应不足而引起的 氧化细胞毒性产物诱导的损伤（例如胆固醇 氧化产物）。氧化产物的水平和功能丧失 在稳态条件下可能很小。因此，我们会扰动 该系统通过体外诱导膜的氧化（主要使用 内源性氧化剂）为了扩大现有差异。我们的 初步研究表明，线粒体胆固醇更可氧化 在PD中而不是在对照中。 线粒体和突触体级分将通过孵育氧化 与氧化剂（例如，花生四角酸和亚油酸氢过氧化物 加上铁，铁和抗坏血酸的混合物，一氧化氮的混合物等金属离子 有和没有超氧化物等）。不同水平的氧化 膜可以通过两个膜脂质的氧化程度来定义 - 生育酚和胆固醇。由于胆固醇的特征和 生育酚氧化产物对各种类型的特征 将获得氧化，有关氧化机制的信息。 来自年轻大鼠和老鼠的突触体和线粒体，PD和对照 在所有研究中，将比较人尸检大脑样品。相似的 血小板氧化的研究（作为神经元的可访问模型 将进行PD和控制受试者的人类膜。这 膜的氧化程度将受到监测和定量 确定生育酚和胆固醇的浓度及其 氧化产物以及通过估计硫巴比妥酸反应性 物质和总羟基烯浓度下降。氧化 对照和对照之间产生最大差异的条件 实验组将首先建立，然后建立胆固醇，然后 将分离，鉴定和定量生育酚氧化产物 由GC和GC-MS。一项单胺氧化酶（MAO）对 线粒体氧化将通过将线粒体与线粒体与 多巴胺，去甲肾上腺素或5-羟色胺（MAO的底物）释放 原位过氧化氢和/或其他从中得出的氧化剂。这 将遵循氧化，氧化产物与 脑部分和脱发抑制对氧化的影响 也将研究。在吸收之间存在相似之处的数量 血小板和大脑的5-羟色胺。血小板和血小板吸收5-羟色胺 将研究各种氧化水平的突触体以检查 氧化对膜功能的影响。数据将用于 确定PD中是否存在氧化应激引起的膜损伤 和/或正常衰老。血小板研究的数据也可能提供 PD临床前诊断的实验室工具。