Heterotypic amyloid interactions as modulators of selective cellular vulnerability

摘要 淀粉样蛋白聚集物是阿尔茨海默病(AD)的决定性病理标志，但它们所扮演的角色 而靶向这些聚集体的治疗效果仍然存在争议。人们对这种影响知之甚少。 这些蛋白质所处的蛋白质组环境，或者是什么使它们在特定的位置聚集 大脑。用蛋白质组学方法研究淀粉样蛋白沉积的组成表明， 许多其他蛋白质的沉积，然而目前还没有直接的事件链来解释 斑块成分。该领域目前所处的困境严重地突显了缺乏适当的 用结构-机制模型来理解淀粉样蛋白聚集的原因和后果 直接的分子相互作用，以及哪些特定的细胞因素决定了病原体疾病 入会仪式。 在这个项目中，VIB佛兰德斯生物技术研究所的Switch实验室将接近选择 阿尔茨海默病中β-淀粉样蛋白(A-β)和tau蛋白聚集的机制及系统研究 基于聚集的序列和结构的特殊性，潜在的相互作用伙伴。这个系统化的 而蛋白质组范围的筛选是基于这样的假设，即淀粉样蛋白聚集是由特定的 β和tau内的聚集区(APR)与聚集性序列片段的相互作用 在背景蛋白质组内的其他蛋白质中。 他们开发了一种独特的计算管道来模拟异型相互作用，并具有足够的预测性 识别细胞中淀粉样蛋白修饰物的能力。该项目将研究异型淀粉样蛋白对体内的影响 在小鼠模型和HITS中的相互作用，将详细分析Aβ和tau的聚集如何 被相互作用所改变。 AIM 1将运行一种硅胶屏幕，特别强调与选择性弱点相关的已知因素。这个 计算性筛选将使用与APRs具有序列同源性的序列片段的全原子建模 以确定其他大脑表达的蛋白，这些蛋白可能会改变Aβ或tau的聚集。目标2将 在细胞模型中筛选全长蛋白以确定能够改变β淀粉样蛋白聚集的候选蛋白 和tau在复杂的生物学背景下。目标3将通过表达在体内具有作用的修饰物 小鼠模型中最有效的修饰蛋白，以研究其对淀粉样蛋白聚集起始和程度的影响 β和tau的病理学。对于目标2和目标3中确定的最有希望的修饰物，目标4将揭开 选择的异型淀粉样蛋白相互作用的分子机制使用最先进的生物物理方法 准确地阐明这些相互作用如何改变A、β和tau的淀粉样蛋白的形成。

ABSTRACT Amyloid aggregates are the defining pathological hallmark of Alzheimer’s Disease (AD), yet the role they play and the therapeutic effect in targeting these aggregates remains controversial. Little is known about the impact of the proteome context in which these proteins reside, or what nucleates their aggregation in specific sites in the brain. Studying the composition of amyloid deposits using proteomic approaches has demonstrated the co- deposition of many other proteins, however currently there is no straightforward chain-of-events that explains plaque composition. The predicament in which the field currently subsists critically highlights the lack of suitable structural-mechanistic models to understand both the causes and consequences of amyloid aggregation in terms of direct molecular interactions, as well as which specific cellular factors determine pathognomonic disease initiation. In this project, the Switch Laboratory in VIB Flanders Institute for Biotechnology will approach the selective amyloid aggregation of beta amyloid (Aβ) and tau in AD mechanistically and will do a systematic search for potential interacting partners based on the sequence- and structure-specificity of aggregation. This systematic and proteome-wide screen is based on the assumption that amyloid aggregation is initiated by the specific interaction of aggregation-prone regions (APRs) within Aβ and tau with aggregation-prone sequence segments in other proteins within the background proteome. They have developed a unique computational pipeline to model heterotypic interactions with sufficient predictive power to identify amyloid modifiers in cells. The project will investigate the in vivo impact of heterotypic amyloid interactions in mouse models and for the hits, will analyze in molecular detail how the aggregation of Aβ and tau is modified by the interactions. Aim 1 will run an in-silico screen with special emphasis on known factors related to selective vulnerably. The computational screen will use all-atom modelling of sequence segments with sequence homology to the APRs of Aβ and tau to identify other brain-expressed proteins that may modify the aggregation of Aβ or tau. Aim 2 will screen full-length proteins in cellular models to identify candidates that can modify amyloid aggregation of Aβ and tau in a complex biological context. Aim 3 will identify modifiers that have an effect in vivo by expressing the most potent modifier proteins in mouse models, to study the impact on aggregation onset and extent of amyloid pathology of Aβ and tau. For the most promising modifiers identified in Aims 2 and 3, Aim 4 will unravel the molecular mechanism of selected heterotypic amyloid interactions use state-of-the-art biophysical methods to elucidate exactly how these interactions change the amyloid formation of Aβ and tau.