Comprehensive Characterization of Glycosylation Alterations in Alzheimer's Disease

项目摘要 阿尔茨海默病(AD)是一种衰弱的神经退行性疾病，尽管 数十年来在诊断和治疗方面的研究和开发投资。因为有这么高 医疗负担和AD对认知功能和生活质量的破坏性影响 疾病以及预防和治疗阿尔茨海默病的干预措施是公共卫生优先事项。寻找生物标记物和 治疗转向了糖生物学，即研究蛋白质和脂类结合的复杂糖类。邮报- 蛋白质和脂类的翻译糖基化在许多关键的生物过程中发挥作用。 包括细胞间的通讯和信号，以及蛋白质的结构和功能。最近，少校 在AD患者的脑、脑脊液和血液中发现了糖基化的改变。 甚至在进展性认知功能衰退开始之前。糖基化可能与阿尔茨海默病有关，因此 测量血液中的糖基化是发现早期生物标志物的一个有前途的策略。载脂蛋白E 载脂蛋白E(APOE)是AD的单一最大遗传风险因素。载脂蛋白E4亚型的携带者是 根据载脂蛋白E4的拷贝数，有可能患上阿尔茨海默病，并发展为多达20 几年前。载脂蛋白E是一种糖基化蛋白质，几乎所有的蛋白质、载体和受体都参与了 它的代谢也是糖基化的。载脂蛋白E的结构对其功能有很大影响。糖基化是 已知可以改变蛋白质结构，但既不会改变载脂蛋白E的糖基化，也不会改变大脑中的总糖基化 而在血液中已经充分表现出阿尔茨海默病患者的特征，因为缺乏 测量糖基化的精确分析工具一直是取得进展的技术障碍。我们的团队 开创了先进和灵敏的液相色谱-质谱学方法的发展 作为同时精确测量数百种脂质和蛋白质糖基化变化的工具。 我们的方法是快速的，可以监测位点特异性、结构特异性和连锁特异性 在数百个临床样本中的所有附着的多糖中，具有很高的重复性、准确性和灵敏度。这个 这个项目的三个具体目标是绘制大脑和血液中的全球糖基化变化图 阿尔茨海默病患者与对照组的比较，以表征部位特异性糖基化的变化 并记录糖基化变化对阿尔茨海默病关键通路的影响 疾病病理学。重要的是，AD中糖基化的差异将被映射到每个ApoE中 这将使基于精确医学的解决方案的发现成为可能。成功完成这项工作 该项目将导致开发新的基于糖基化的生物标记物，用于早期检测 阿尔茨海默病和载脂蛋白E的特定靶点，用于开发治疗阿尔茨海默病的新疗法。

Project Summary Alzheimer’s disease (AD) is a debilitating neurodegenerative disease that is growing in prevalence despite decades of investment in the research and development of diagnostics and therapeutics. Because of the high healthcare burden and devastating effects of AD on cognitive function and quality of life, early biomarkers of disease and interventions to prevent and treat AD are a public health priority. The search for biomarkers and treatments has turned to glycobiology, the study of complex sugars attached to proteins and lipids. The post- translational glycosylation of proteins and lipids plays a role in a number of critical biological processes including cell-to-cell communication and signaling, and protein structure and function. Recently, major alterations in glycosylation have been documented in the brains, cerebrospinal fluid, and blood of AD patients even before the onset of advanced cognitive decline. Glycosylation is likely to be causally involved in AD, thus measuring glycosylation in blood is a promising strategy for discovering early biomarkers. Apolipoprotein E (ApoE) is the single greatest genetic risk factor for AD. Carriers of the ApoE4 isoform are 4-12 times more likely to develop AD depending on the number of copies of ApoE4, and develop the disease as many as 20 years earlier. ApoE is a glycosylated protein, and nearly all of the proteins, carriers, and receptors involved in its metabolism are also glycosylated. The structure of ApoE heavily influences its functionality. Glycosylation is known to alter protein structure yet neither the glycosylation of ApoE, nor the overall glycosylation in the brain and in the blood have been adequately characterized in Alzheimer’s disease patients because the lack of precise analytical tools for measuring glycosylation has been a technological barrier to progress. Our group has pioneered the development of advanced and sensitive liquid chromatography-mass spectrometry methods as tools to precisely measure glycosylation alterations across hundreds of lipids and proteins simultaneously. Our method is rapid-throughput and can monitor the site-specificity, structure specificity, and linkage specificity of all attached glycans in hundreds of clinical samples with high reproducibility, accuracy and sensitivity. The three specific aims of this project are to map the global glycosylation alterations in the brains and blood of Alzheimer’s disease patients compared with controls, to characterize the site-specific changes in glycosylation of ApoE, and to document the effects of glycosylation changes on critical pathways involved in Alzheimer’s disease pathology. Importantly, the differences in glycosylation in AD will be mapped within each ApoE genotype, which will enable the discovery of precision medicine based solutions. Successful completion of this project will lead to the development of new glycosylation-based biomarkers for the early detection of Alzheimer’s disease and ApoE-specific targets for the development of novel therapeutics in AD.