Pathogenic Mechanisms of Cell-Derived Abeta Oligomers

细胞源性 Abeta 寡聚物的致病机制

• 批准号: 7027342
• 负责人: DENNIS J SELKOE
• 金额: $ 44.18万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7027342
• 关键词: Alzheimer' s disease; amyloid proteins; binding proteins; cell line; chemical aggregate; crosslink; embryo /fetus tissue /cell culture; genetically modified animals; hippocampus; laboratory mouse; laboratory rat; mass spectrometry; molecular pathology; neurotoxins; phosphorylation; polymerization; synapses; tau proteins

DESCRIPTION (provided by applicant): An enduring principle for successful intervention in human disease is to identify - and then prevent - the earliest steps in pathogenesis. In the case of Alzheimer's disease and its harbinger, mild cognitive impairment (MCI), studies from many labs support the still unproven hypothesis that the gradual accumulation and oligomerization of amyloid p-protein (AB) in brain regions serving memory and cognition initiates this complex syndrome. Given the enormous resources being expended by academic and pharmaceutical scientists to identify anti-amyloid therapies and bring them to human trials, it is crucial to understand precisely how soluble AB begins to oligomerize and whether this process actually induces the subtle compromise of synaptic function seen in MCI and early AD. In this new RO1 application, investigators who have collaborated productively to discover the natural secretion of low-n AB oligomers in cell culture and then demonstrate their ability to inhibit long-term potentiation and disrupt memory in living animals now propose to rigorously define at the molecular level these earliest AB assembly forms and elucidate their mechanisms of action on neuronal function. Based on extensive preliminary data and sensitive biochemical methods we have developed to isolate and study natural oligomers, we propose 4 interrelated Specific Aims. 1. Determine the precise molecular composition of naturally secreted AB oligomers by mass spectrometry and search for covalent crosslinks, associated small molecules and/or binding proteins that may contribute to their potent neuronal activity. 2. Characterize the effects of the natural oligomers on synaptic form and function, including in organotypic hippocampal cultures, and assess whether they can induce AD-type tau phosphorylation and altered transmitter release in vivo, 3. Purify the natural oligomers to homogeneity, intrinsically label them and identify their cognate molecular and cellular targets in living brain. 4. Assess 3 specific therapeutic strategies to decrease the production of cell-secreted oligomers and thereby abrogate their synaptotoxicity: (B- or y-secretase inhibitors; certain anti-aggregation compounds; and chaperone expression. Our extensive experience in studying this unlimited cellular source of physiological amounts of human AB oligomers should enable us to exploit this unique experimental paradigm to elucidate both the nature and the neuronal effects of the earliest AB assemblies, with attendant therapeutic implications. Relevance to Public Health: Because our central hypothesis is that the earliest-forming "oligomers" (doublets, triplets, etc.) of amyloid B-protein underlie the subtle and progressive impairment of memory that is the hallmark of incipient AD, we will use a unique experimental system in which cultured cells naturally produce such early forms in order to decipher the precise nature of these pathogenic assemblies, identify their mechanism of injury on the neurons and synapses required for memory, and then block this process with novel drugs.

描述（由申请人提供）：成功干预人类疾病的一个持久原则是识别-然后预防-发病机制的最早步骤。在阿尔茨海默病及其先兆轻度认知障碍（MCI）的案例中，许多实验室的研究支持了一个尚未证实的假设，即淀粉样蛋白p （AB）在大脑中服务于记忆和认知的区域的逐渐积累和寡聚化引发了这种复杂的综合征。鉴于学术和制药科学家花费了大量资源来确定抗淀粉样蛋白疗法并将其用于人体试验，因此准确了解可溶性AB是如何开始寡聚的，以及这一过程是否实际上导致了MCI和早期AD中所见的突触功能的微妙损害，这一点至关重要。在这个新的RO1应用中，研究人员合作发现了低n AB低聚物在细胞培养中的自然分泌，然后证明了它们在活体动物中抑制长期增强和破坏记忆的能力，现在他们建议在分子水平上严格定义这些最早的AB组装形式，并阐明它们对神经元功能的作用机制。基于广泛的初步数据和灵敏的生化方法，我们已经开发出分离和研究天然低聚物，我们提出了4个相互关联的具体目标。通过质谱测定自然分泌的AB寡聚物的精确分子组成，并寻找共价交联，相关的小分子和/或结合蛋白，可能有助于其有效的神经元活性。2. 表征天然低聚物对突触形式和功能的影响，包括在器官型海马培养中，并评估它们是否能诱导ad型tau磷酸化和体内递质释放的改变，3。纯化天然低聚物至同质性，对其进行本质标记，并鉴定其在活脑中的同源分子和细胞靶点。4. 评估3种特定的治疗策略，以减少细胞分泌的低聚物的产生，从而消除其突触毒性：B-或y-分泌酶抑制剂；某些抗聚集化合物；和伴侣蛋白表达。我们在研究人类AB寡聚物生理量的无限细胞来源方面的丰富经验应该使我们能够利用这种独特的实验范式来阐明最早的AB组装的性质和神经元效应，以及随之而来的治疗意义。与公共卫生有关：因为我们的中心假设是最早形成的淀粉样b蛋白“低聚物”（双、三胞胎等）是早期阿尔茨海默病的标志，是记忆的微妙和渐进损害的基础，我们将使用一个独特的实验系统，培养细胞自然产生这种早期形式，以解释这些致病性组合的确切性质，确定它们对记忆所需的神经元和突触的损伤机制。然后用新药阻断这个过程。