Comprehensive Characterization of Glycosylation Alterations in Alzheimer's Disease

项目摘要 阿尔茨海默氏病（AD）是一种使人衰弱的神经退行性疾病， 在诊断和治疗的研究和开发方面的数十年投资。由于高 AD对认知功能和生活质量的破坏性影响， 预防和治疗AD的干预措施是公共卫生的优先事项。寻找生物标志物和 治疗已经转向糖生物学，研究与蛋白质和脂质结合的复合糖。邮报- 蛋白质和脂质的翻译糖基化在许多关键的生物过程中起作用 包括细胞间的通讯和信号传导，以及蛋白质的结构和功能。近期各大 在AD患者的脑、脑脊液和血液中已经记录了糖基化的改变 甚至在高级认知能力下降之前。糖基化可能与AD有因果关系，因此 测量血液中的糖基化是发现早期生物标志物的有希望的策略。载脂蛋白E ApoE是AD的最大遗传风险因素。ApoE 4亚型携带者比正常人高4-12倍， 根据ApoE 4的拷贝数，有可能患上AD， 几年前。ApoE是一种糖基化的蛋白质，几乎所有参与ApoE的蛋白质、载体和受体都是糖基化的。 其代谢也是糖基化。ApoE的结构严重影响其功能。糖基化是 已知改变蛋白质结构，但既不改变ApoE的糖基化，也不改变大脑中的整体糖基化 在阿尔茨海默病患者中已经得到了充分的表征， 用于测量糖基化的精确分析工具一直是进步的技术障碍。我们集团 率先开发了先进灵敏的液相色谱-质谱联用方法 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，结构特异性和连接特异性 分析数百个临床样本中的所有连接聚糖，具有高重现性、准确性和灵敏度。的 该项目的三个具体目标是绘制大脑和血液中的全球糖基化改变， 阿尔茨海默病患者与对照组相比，以表征糖基化的位点特异性变化 的ApoE，并记录糖基化变化对阿尔茨海默氏症的关键途径的影响， 疾病病理学重要的是，AD中糖基化的差异将在每个ApoE中定位。 基因型，这将有助于发现基于精准医学的解决方案。成功完成本 该项目将导致开发新的基于糖基化的生物标志物，用于早期检测 阿尔茨海默病和Apoe特异性靶点用于开发AD新型治疗方法。

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.