Drivers of Pathological Tau Aggregation

项目摘要 tau蛋白病治疗发展的瓶颈是缺乏经验证的tau蛋白病模型，小鼠，细胞或体外。 这反映在当前的现实中，即通过冷冻EM从尸检中解决了tau蛋白病特异性纤维结构， 患者脑组织从未在患者体外复制，即不在小鼠、细胞或体外复制。当病人- 衍生的tau蛋白病原纤维提供关键的目标岗位，它们本身不是可行的治疗靶标。为 例如，开发正电子发射断层扫描（PET）配体来诊断和跟踪阿尔茨海默病 (AD)或皮质基底节变性（CBD）疾病进展依赖于筛选与CBD结合的小分子-或 AD-表型纤维-非常结构，没有人知道如何建立。还有很多因素需要考虑 复制tau聚集的病理途径，但复制疾病表型tau纤维是最小的 和必要的要求，以及迄今为止尚未实现的治疗开发工具。主要的知识差距， 该提议旨在关闭在体外复制Tau蛋白病特异性原纤维的机制和工具（目的1）， 以及启动细胞中tau错误折叠形成疾病表型形状的关键细胞和分子因子 并促进聚合（目标2）。如果我们能成功复制任何一种tau蛋白病-表型tau折叠， 折叠的tau结构的一部分，例如具有播种能力的CBD或AD的微型发夹折叠，其将具有 对正在进行的治疗开发的直接影响，例如对tau蛋白病特异性PET配体的开发， 抗体和小分子药物。该团队将采用一套创新的结构生物学工具， 脉冲双电子-电子共振（DEER），TEM和cryo-EM，以及计算工具，重点放在 捕获tau蛋白整体的完整折叠和聚集途径， 部分折叠和完全会聚的原纤维状态。该团队将同时使用创新的细胞生物学工具， 一个强有力的前提知识的专用tau受体和转运蛋白，可以增强tau播种， 内体逃逸和tau局部环境疏水性增强是一个有效因素的知识 以引发错误折叠、聚集和传播。当发现一个有能力的种子的定义属性时， 与此无关，用该提议中开发的种子实现形状繁殖将是一个突破。 如果成功，我们将开发实验和计算工具来评估是否有种子形状， 是否发生了传播，或者是否所有、部分或没有形状传播。要有工具来评估 形状传播的机制将改变游戏规则。在关闭上述设施方面缺乏进展， 知识差距不是由于缺乏世界一流实验室的投资，而是由于存在缺陷 现有的概念和工具。汉和科西克，连同谢伊，将依靠他们各自的收敛， 领域和投资协调一致的努力，使用创新的工具，以解决长期存在的问题，在tau蛋白病研究。

PROJECT SUMMARY The bottleneck for tauopathy therapy development is the lack of validated tauopathy models, mouse, cell or in vitro. This is reflected in the current reality that tauopathy-specific fibril structures solved by cryo-EM from post mortem patient brain tissue have never been replicated outside a patient, i.e. not in a mouse, cell or in vitro. While the patient- derived tauopathy fibrils offer critical goal posts, they are not in and of themselves viable therapeutic targets. For example, the development of Positron Emission Tomography (PET) ligands to diagnose and track Alzheimer’s disease (AD) or corticobasal degeneration (CBD) disease progression relies on screening small molecule binding to CBD- or AD-phenotypic fibrils—the very construct that nobody knows how to build yet. There are many more factors to consider for replicating the pathological pathway of tau aggregation, but replicating disease phenotypic tau fibrils is a minimal and necessary requirement, and so far an unattained tool for therapy development. The major knowledge gap that this proposal aims to close is the mechanism and tools to replicate tauopathy specific fibrils in vitro (Aim 1), and the key cellular and molecular factors that initiate misfolding of tau in cell to disease phenotypic shapes and facilitate aggregation (Aim 2). If we can successfully replicate any one tauopathy-phenotypic tau fold, or even a part of a folded tau structure, such as a mini-hairpin fold of CBD or AD with seeding competency, it will have an immediate impact on ongoing therapy developments, such as on the development of tauopathy-specific PET ligands, antibodies and small molecule drugs. This team will employ an innovative set of structural biology tools encompassing pulsed double electron-electron resonance (DEER), TEM and cryo-EM, as well as computational tools to focus on capturing the full folding and aggregation pathway of the tau protein ensemble from its intrinsically disordered to partially folded and fully converged fibril states. This team will concurrently use innovative cell biological tools with a strong premise of the knowledge of a dedicated tau receptor and transporter that can enhance tau seeding by endosomal escape and the knowledge that enhanced hydrophobicity of the local environment of tau is a potent factor to initiate misfolding, aggregation and propagation. While discovering the defining property of a competent seed and achieving shape propagation with seeds developed in this proposal will be a breakthrough, independent of this success, we will have developed experimental and computational tools to evaluate whether seeded shape propagation has occurred, or whether all, part, or none of the shape propagates. To have the tools to evaluate the mechanism of shape propagation will be a game changer. The lack of progress in closing the above-described knowledge gap is not due to a lack of investment by top notch laboratories around the world, but due to shortcomings of existing concepts and tools. Han and Kosik, together with Shea, will rely on the convergence of their respective fields and investing concerted effort using innovative tools to address long-standing questions in tauopathy research.