Abeta oligomers (ADDLs) in Alzheimer's Disease pathology

描述(申请人提供)：本申请涉及阿尔茨海默病(AD)不同阶段患者大脑和脑脊液中Abeta寡聚体(ADDLS)的病理性积聚。在65岁以上的人中，这种疾病的发病率为10%，给家庭带来痛苦的情感负担，每年给国家造成超过1000亿美元的损失。尽管它的严重影响，我们抗击阿尔茨海默病的能力受到不准确的诊断和不充分的治疗。目前的项目通过研究ADDLS的临床特性来解决这些问题，我们确定ADDLS是积聚在AD脑和脑脊液中的亚稳态神经毒素。现在看来，ADDLS可能在导致AD渐进性灾难性痴呆的神经元功能障碍和损伤中发挥重要作用(卫生与人类服务2004-2005年阿尔茨海默病进展报告)。为了推进我们对这种致病作用的低估，我们建议检验这样一种假设，即ADDLS攻击突触会启动tau过度磷酸化、氧化损伤和突触恶化，从而为记忆衰竭和AD神经病理的主要方面提供一个全面的机制。这一假说得到了细胞生物学和神经病理学的有力支持，将主要使用人类ADDLS和中枢神经系统样本进行研究，以便直接建立临床相关性。我们还建议调查为什么受AD影响的大脑不能清除ADDLS，跟进最近报道的神经病理数据，表明神经胶质细胞清除机制失败。基于最近的结果，我们的七个目标是：(I)验证脑脊液/血浆中的ADDLS提供可靠的AD生物标记物；(Ii)验证AD的最早临床前迹象是ADTL在单个神经元周围聚集；(Iii)检验ADDLS包围的神经元发展为AD病理的预测；(Iv)验证ADDLS的神经细胞沉积是由于ADT1附着到突触上；(V)鉴定致病意义的寡聚体物种(大约12个)，并获得新的针对疾病相关寡聚体的单抗；(Vi)测试突触膜蛋白在ADDLS仅攻击特定神经元的机制中的预测作用；以及，(Vii)确认在星形胶质细胞中发现的与Add1相关的新病理，测试其与疾病发生和进展中失败的Add1清除机制的相关性。重要的技术创新包括基于超灵敏纳米技术的ADTL分析、针对溶液中ADDLS的单抗，以及一系列能够在不使用十二烷基硫酸钠或其他苛刻化学物质的情况下表征稀水溶液中齐聚物大小的物理化学方法。预计结果将提供验证和优化ADDLS作为阿尔茨海默氏症诊断和疾病修改治疗的主要目标所需的重要进展。公共卫生相关性：这项应用涉及Abeta寡聚体(ADDL)在阿尔茨海默病中的作用，重点是在人类样本上建立直接的临床和病理相关性。利用人类ADDLS和组织获得的结果将有助于回答ADTL参与发病机制的重要问题，并证实ADDLS在未来的诊断和治疗中的靶向。

DESCRIPTION (provided by applicant): This application concerns the pathological accumulation of Abeta oligomers (ADDLs) in brains and CSF of individuals at various stages of Alzheimer's disease (AD). This disease strikes 10 percent of individuals over 65, inflicting painful emotional burden to families and a cost to the country of more than $100 billion annually. Despite its serious impact, our ability to contend with AD suffers from imprecise diagnostics and inadequate therapeutics. The current project addresses these problems by investigating the clinical properties of ADDLs, which we identified as metastable neurotoxins that accumulate in AD brain and CSF. It now appears likely that ADDLs play a significant role in the neuronal dysfunction and damage responsible for AD's progressively catastrophic dementia (Health & Human Services 2004-2005 Progress Report on Alzheimer's Disease). To advance our understating of this pathogenic role, we propose to test the hypothesis that an attack on synapses by ADDLs initiates tau hyperphosphorylation, oxidative damage and synapse deterioration, thus providing a comprehensive mechanism for memory failure and the major facets of AD neuropathology. This hypothesis, which is strongly supported by findings from cell biology and neuropathology, will be investigated primarily using human ADDLs and CNS samples in order to directly establish clinical relevance. We also propose to investigate why AD-affected brain is unable to remove ADDLs, following up on newly reported neuropathological data suggesting a failure of glial clearance mechanisms. Building on recent results, our seven aims are to: (i) Validate that ADDLs in CSF/plasma provide a reliable AD biomarker; (ii) Verify that the earliest preclinical sign of AD is ADDL accumulation around individual neurons; (iii) Test the prediction that neurons surrounded by ADDLs develop AD pathology; (iv) Verify that perineuronal deposits of ADDLs are due to ADDL attachment to synapses; (v) Identify the pathogenically significant oligomeric species (putatively 12mers) and obtain new monoclonal antibodies that specifically target disease-relevant oligomers; (vi) Test the predicted role of synaptic membrane proteins in the mechanism by which ADDLS attack only particular neurons; and, (vii) Confirm the novel ADDL-related pathology discovered in astrocytes, testing its relevance to failed ADDL clearance mechanisms in disease onset and progression. Important technical innovations include ultrasensitive nanotechnology-based ADDL assays, monoclonal antibodies specific for ADDLs in solution, and a series of physicochemical methods capable of characterizing oligomer size in dilute aqueous solutions without the use of SDS or other harsh chemicals. Results are expected to provide important advances needed to validate and optimize ADDLs as major targets for Alzheimer's diagnostics and disease-modifying therapeutics. PUBLIC HEALTH RELEVANCE: This application concerns the role of Abeta oligomers (ADDLs) in Alzheimer's disease, focusing on human samples to establish direct clinical and pathological relevance. Results obtained with human ADDLs and tissue will help answer important questions central to ADDL involvement in pathogenesis and substantiate the targeting of ADDLs for future diagnostics and therapeutics.