Harnessing new targets and mechanisms mediating AD pathogenesis

阿尔茨海默病（AD）是一种无法治愈的神经退行性脑部疾病，会导致进行性记忆丧失和认知能力下降，是痴呆症的第一大病因。其特征是细胞外淀粉样斑块（主要由淀粉样蛋白β -42 （Abeta）肽形成）和细胞内含有异常tau聚集物的神经原纤维缠结共存。多年来，Abeta和tau被认为是互不关联的罪魁祸首，但鉴于最近的研究，它们显然是密切相关的，并具有协同作用。遗憾的是，我们对Abeta和tau相互作用如何引发AD发病机制知之甚少，这极大地阻碍了有效治疗方法的发展。为了解决这个问题，我们建立了一种新的AD苍蝇模型，该模型在遗传上产生人类β和tau蛋白，从而导致协同病理。这些果蝇表现出硫黄素- s阳性β的细胞外沉积，细胞内聚集和野生型tau的磷酸化，以及神经元细胞的进行性损失。这些果蝇的强大和一致的病理为基因发现工作提供了一个独特的机会，因此我们在果蝇眼睛中进行了大量的功能缺失RNAi筛选，这提供了一个有用且易于评分的表型。在测试的6600个RNAi库存中，我们确定了31个抑制子和119个增强子，包括多个以前不知道与AD相关的基因。大多数抑制因子与蛋白质修饰或切割、核糖体功能、细胞代谢、转录、染色质调节和运输等有关。在这里，我们将采用一种战略性设计的管道，将遗传学与高通量行为平台和目标优先级结合起来，以确定疾病的强大晚期修饰因子（目的1）。另一方面，我们将快速追踪其中一种最强的抑制因子及其人类同源物的机制和治疗分析（目标2）。该抑制因子编码一种功能不明确的高度紊乱蛋白，在我们进行的另外两个遗传筛选中也发现了该抑制因子。因此，我们把它列为高度优先的目标。我们坚信，本文提出的150种Abeta+tau毒性修饰剂的操作将为新型靶点或治疗方法提供基础。因此，这项工作可能对解决阿尔茨海默病国家计划的目标作出重大贡献。

Alzheimer’s disease (AD) is an incurable neurodegenerative brain disorder that causes progressive memory loss and cognitive decline, and is the No.1 cause of dementia. It is characterized by the coexistence of extracellular amyloid plaques, mainly formed by the amyloid beta-42 (Abeta) peptide, and intracellular neurofibrillary tangles containing aggregates of abnormal tau. Abeta and tau were considered as disconnected culprits for many years, but in view of recent studies, it is clear that they are intimately related and possess synergistic activities. Sadly, very little is known about how Abeta and tau interactions trigger AD pathogenesis, which significantly hinders the development of effective treatments. To address this, we generated a new fly model of AD that genetically produces both human Abeta and tau resulting in synergistic pathology. These flies display extracellular deposits of thioflavin-S-positive Abeta, intracellular aggregation and phosphorylation of wild-type tau, and progressive loss of neuronal cells. The robust and consistent pathology of these flies provides a unique opportunity for gene discovery efforts and thus we performed a massive loss-of-function RNAi screen in the fly eye, which provides a useful and easy-to-score phenotype. Out of 6,600 RNAi stocks tested, we identified 31 suppressors and 119 enhancers, including multiple genes not previously known to be associated with AD. Most suppressors are linked to protein modification or cleavage, ribosomal function, cell metabolism, transcription, chromatin modulation, and transport to name a few. Here, we will employ a strategically designed pipeline that integrates genetics with high-throughput behavioral platforms and target prioritization to identify robust late-stage modifiers of the disease (Aim 1). On the other hand, we will fast-track a mechanistic and therapeutic analysis of one of the strongest suppressors along with its human homologue (Aim 2). This suppressor encodes a highly disordered protein of uncharacterized function and was also found in two other genetic screens performed by us. Thus, we have labelled it as a high-priority target. We strongly believe that manipulation of the 150 modifiers of Abeta+tau toxicity presented here will provide the foundation for new types of targets or therapeutics. Therefore, this work may contribute significantly to the goals of the National Plan to Address Alzheimer’s Disease.