The role of human ApoE in soluble ABeta clearance through the LDLR in vivo

人 ApoE 在体内通过 LDLR 清除可溶性 Aβ 中的作用

• 批准号: 7752282
• 负责人: Joseph Michael Castellano
• 金额: $ 4.12万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7752282
• 关键词: APP-PS1; Abeta clearance; Affect; Affinity; Age; Alleles; Alzheimer' s Disease; American; Apolipoprotein E; Binding; Blood - brain barrier anatomy; Brain; Brain region; Breeding; Cells; Cessation of life; Complement; Data; Dementia; Deposition; Development; Disease; Extracellular Space; Goals; Half-Life; Health Care Costs; Healthcare; Hour; Human; Immunohistochemistry; Intercellular Fluid; LDL-Receptor Related Protein 1; Late Onset Alzheimer Disease; Lead; Link; Low Density Lipoprotein Receptor; Measures; Mediating; Memory; Metabolic Clearance Rate; Microdialysis; Motivation; Mus; Pathogenesis; Pathology; Patients; Pattern; Peptides; Population; Process; Production; Protein Isoforms; Public Health; Regulation; Research; Research Proposals; Role; Route; Structure; Techniques; Transgenic Mice; Transgenic Model; age related; aged; apolipoprotein E-3; apolipoprotein E-4; care burden; cognitive function; design; effective therapy; extracellular; gamma secretase; genetic risk factor; in vivo; inhibitor/antagonist; novel; overexpression; receptor; research study; thioflavine

DESCRIPTION (provided by applicant): The leading cause of dementia is Alzheimer's disease (AD), which is characterized by a progressive loss of cognitive function and memory, ultimately leading in death. It is estimated that over 5 million Americans currently suffer for AD, and the direct healthcare cost associated with AD and related dementias annually exceeds $145 billion. As the population ages over the next several decades, the health-care burden presented by AD will be staggering. Understanding the pathogenesis of this age-related disease is c critical to the development of effective therapies and is the primary motivation for this research proposal. Deposition of the Amyloidal (3 (A|3) peptide in the extracellular space of the brain constitutes one of the key pathological hallmarks of AD. Inheritance of apolipoprotein E4 (apoE4) is the major genetic risk factor for late-onset AD identified so far, while apoE2 inheritance appears to be protective. Toxic accumulation of the A(3 peptide is likely regulated by the rates of its production and its clearance from the interstitial fluid (ISF) of the brain; since apoE does not affect the synthesis of Ap, it likely regulates A|3 clearance from the ISF. Our group and others have shown that the binding between apoE and Ap influences Ap deposition and its clearance ifrom the brain. Abundant evidence indicates that the low density lipoprotein receptor (LDLR) is a major apoE receptor in the brain, likely providing an important clearance route for soluble Ap from the ISF. The process by which LDLR regulates Ap clearance in the context of human apoE isoforms remains poorly understood. My objective is to determine the role of LDLR in regulating human apoE-mediated clearance of Ap from the ISF. I hypothesize that apoE-mediated elimination of Ap from the ISF is facilitated by LDLR and follows a pattern that is isoform-dependent such that Ap clearance rate for apoE2 > apoE3 > apoE4. In Specific Aim 1,1 will use our in vivo microdialysis technique to directly assess Ap clearance in mice expressing each of the human apoE isoforms, comparing them to the same mice lacking LDLR. To complement this study, I will determine the AP half-life in the ISF of mice overexpressing LDLR and each of the human apoE isoforms. In Specific Aim 2,1 will analyze extracellular pools of Ap in mice overexpressing LDLR and each of the human apoE isoforms at ages prior to and after Ap deposition to assess LDLR's regulation of Ap levels in regions of the brain where deposits form. To assess the effect of LDLR on Ap deposition in the context of human apoE, I will quantify plaque load in brain sections from each of the groups of mice. The relevance of my proposed research plan to public health is that understanding the mechanisms by which LDLR and human apoE act to mediate Ap clearance will be critical to designing effective new therapies for AD.

描述(申请人提供)：痴呆症的主要原因是阿尔茨海默病(AD)，其特征是认知功能和记忆的进行性丧失，最终导致死亡。据估计，目前有超过500万美国人患有阿尔茨海默病，每年与阿尔茨海默病和相关痴呆症相关的直接医疗成本超过1450亿美元。随着未来几十年人口老龄化，AD带来的医疗负担将是惊人的。了解这种年龄相关性疾病的发病机制对于开发有效的治疗方法至关重要，也是本研究提案的主要动机。淀粉样多肽(3(A|3))沉积在脑细胞外间隙是AD的重要病理特征之一。到目前为止，载脂蛋白E4(ApoE4)的遗传是晚发性AD的主要遗传危险因素，而apoE2的遗传似乎具有保护性。A(3)肽的毒性蓄积可能受其产生的速度和其从脑间质液体(ISF)的清除的调节；由于apoE不影响AP的合成，它可能调节A|3从ISF的清除。我们的团队和其他人已经证明，apoE和AP之间的结合影响AP的沉积及其从大脑中的清除。大量证据表明，低密度脂蛋白受体(LDLR)是脑内主要的载脂蛋白E受体，可能为可溶性AP从ISF中清除提供了重要途径。LDLR在人类载脂蛋白E亚型背景下调节AP清除的过程仍然知之甚少。我的目的是确定LDLR在调节人载脂蛋白E介导的AP从ISF中清除中的作用。我假设apoE介导的AP从ISF中的消除是由LDLR促进的，并且遵循一种依赖于异构体的模式，从而APOE2&>apoE3&>apoE4的AP清除率。在特定的目标1，1将使用我们的体内微透析技术来直接评估表达每种人apoE亚型的小鼠的AP清除，并将它们与缺乏LDLR的相同小鼠进行比较。为了补充这项研究，我将测定过度表达LDLR和每种人类apoE亚型的小鼠在ISF中的AP半衰期。在特定的目标2，1将分析在AP沉积前后年龄的过度表达LDLR和每个人apoE亚型的小鼠的AP胞外池，以评估LDLR对形成AP的大脑区域中AP水平的调节。为了在人类载脂蛋白E的背景下评估LDLR对AP沉积的影响，我将量化每组小鼠脑切片中的斑块负载。我提议的研究计划与公共卫生的相关性在于，了解LDLR和人类载脂蛋白E调节AP清除的机制对于设计有效的AD新疗法至关重要。