The Role of Cholesterol in Alzheimer's Disease

胆固醇在阿尔茨海默病中的作用

• 批准号: 7104974
• 负责人: ALISON M GOATE
• 金额: $ 3.94万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7104974
• 关键词: Alzheimer' s disease; Bosnia-Hercegovina; CHO cells; amyloid proteins; apolipoprotein E; aspartic endopeptidases; biotechnology; cholesterol; chromosome aberrations; endocytosis; enzyme activity; family genetics; genetic screening; genetic susceptibility; genotype; homeostasis; immunoprecipitation; intracellular transport; linkage disequilibriums; molecular pathology; pathologic process; presenilin; protein metabolism; quantitative trait loci; single nucleotide polymorphism; western blottings

DESCRIPTION (provided by applicant): There is growing interest in the potential contribution of cholesterol to the pathogenesis of Alzheimer's disease (AD). Treatment with cholesterol-lowering statins appears to lower the risk of developing AD. Furthermore, Abeta production has been directly associated with cholesterol-rich domains (lipid rafts) and cholesterol levels have been shown to modulate APR processing and Abeta generation. The link between cholesterol and Abeta has recently been revealed in Niemann Pick Type C (NPC) diseases as well as AD. Deficiency in NPC1 protein causes intracellular accumulation of unesterified cholesterol in late endosomal/lysosomal compartments that is accompanied by a significant increase in Abeta production and a shift in presenilin 1 (PS1) localization to early/late endosomes. Contradictory results were reported on whether changes in cholesterol content may directly affect gamma-secretase cleavage of APP. The goal of this project is to elucidate the mechanisms by which cholesterol affects APP metabolism. We hypothesize that cholesterol modulates APP processing in a similar manner in wild-type and NPC1 knock-out cells. We also hypothesize that cholesterol levels regulate intracellular trafficking of APP, BACE1 and PS1, three key players in the pathogenesis of Alzheimer's disease. We speculate that cholesterol-dependent association with lipid rafts of the three proteins regulates their endocytosis and thus generation of Abeta. In addition, we hypothesize that levels of cholesterol and/or apolipoprotein E (apoE) modulate APP processing directly regulating gamma-secretase activity. To analyze the parallels between cholesterol and APP processing in wild-type and NPC1-/- cells we will test whether an increase or a decrease in cholesterol levels modulates APP metabolism in a similar manner. Comparing cellular localization and association with lipid rafts of APP, BACE1 and PS1 in wt and in NPC1 Knock out cells under sterol-starved and sterol-fed conditions we will elucidate whether the cholesterol-effect on aberrant APP processing is mediated via specific subcellular or lipid raft compartment(s). To test whether gamma-secretase activity per se can be regulated by cholesterol and/or apoE levels we will perform in vitro gamma-assay. If gamma-secretase activity is regulated by cholesterol levels and/or apoE we will test whether this feature is specific for gamma-cleavage of APP or is common among other gamma-secretase substrates (e.g. Notch 1). This research will be done primarily in Croatia at the Rudjer Boskovic Institute in collaboration with Dr. Silva Hecimovic as an extension of NIH grant #R01AG016208. Through these studies we will elucidate the molecular mechanisms of cholesterol action in Alzheimer's disease. Finding the molecular link(s) between cholesterol and AD is important both for treating Alzheimer's disease as well as for understanding normal APP function.

描述（由申请人提供）：对胆固醇对阿尔茨海默氏病（AD）的潜在贡献的潜在贡献越来越兴趣。降低胆固醇的汀类药物的治疗似乎降低了发展AD的风险。此外，ABETA的产生与富含胆固醇的结构域（脂质筏）直接相关，并且已证明胆固醇水平可调节APR加工和ABETA的产生。胆固醇和Abeta之间的联系最近在Niemann Pick型（NPC）疾病以及AD中得到了揭示。 NPC1蛋白的缺乏会导致内体/溶酶体晚期中未酯化胆固醇的细胞内积累，伴随着ABETA产生的显着增加和老龄素1（PS1）定位的变化，向早期/晚期内体内体。报道了矛盾的结果，有关胆固醇含量的变化是否可能直接影响APP的γ-分泌酶裂解。该项目的目的是阐明胆固醇影响应用代谢的机制。我们假设胆固醇在野生型和NPC1敲除细胞中以类似的方式调节应用程序处理。我们还假设胆固醇水平调节APP，BACE1和PS1的细胞内运输，这是阿尔茨海默氏病发病机理的三个关键参与者。我们推测，胆固醇依赖于三种蛋白的脂质筏的缔合可调节其内吞作用，从而产生Abeta。此外，我们假设胆固醇和/或载脂蛋白E（APOE）的水平直接调节APP处理，从而直接调节γ-分泌酶活性。为了分析胆固醇和野生型和NPC1 - / - 细胞中的相似之处，我们将测试胆固醇水平的增加还是降低胆固醇水平会以类似的方式调节APP代谢。将WT中的APP，BACE1和PS1的细胞定位和与NPC1中的APP，BACE1和PS1的脂质缔合，在固醇饥饿和固醇喂养的条件下敲除细胞，我们将阐明是否通过特定的亚细胞或脂质Raft Raft Raft Cartment（S）介导了异常APP处理上的胆固醇效应。为了测试γ-分泌酶活性本身是否可以受到胆固醇和/或APOE水平的调节，我们将在体外伽马测定中执行。如果γ-分泌酶活性受胆固醇水平调节和/或APOE，我们将测试此功能是否针对APP的γ-切除术，还是在其他γ-分泌酶底物（例如Notch 1）中常见。这项研究将主要在克罗地亚在鲁德杰·博斯科维奇学院（Rudjer Boskovic Institute）与Silva Hecimovic博士合作，作为NIH赠款＃R01AG016208的扩展。通过这些研究，我们将阐明阿尔茨海默氏病中胆固醇作用的分子机制。找到胆固醇和AD之间的分子联系对于治疗阿尔茨海默氏病以及了解正常的应用功能都很重要。