Characterization of the structural and molecular properties of propagating tau in vitro and in vivo

项目概要/摘要。 Tau蛋白在包括阿尔茨海默病在内的许多神经退行性疾病中积累成致病性沉积物 疾病（AD）和一些形式的Gerstmann-Sträussler-Scheinker病（GSS）。使用低温电子 最近的突破性研究已经确定了多个tau蛋白的存在， 构象异构体，其在tau疾病之间可能不同。AD和GSS中的tau聚集体包含所有6种亚型 的tau蛋白，两者都已被超微结构确定含有成对的螺旋丝（PHF）。然而在 AD中，存在与PHF相同的超微结构多晶型物，其由相同的氨基酸序列组成，但具有不同的氨基酸序列。 不同的界面，称为直丝（SF）。这些SF在GSS中没有发现，也不知道为什么tau 在AD中会折叠成PHF而不是SF。这意味着针对特定tau蛋白的治疗方法 构象异构体可能不适合疾病中的所有tau多晶型物。许多研究已经证明 tau蛋白以“朊病毒样”方式起作用，将致病性“供体”tau蛋白的错误折叠模板化为幼稚的“受体”tau蛋白， 在tau疾病的体外和体内模型中。然而，供体tau蛋白如何作为受体tau蛋白的模板， 其机制将提供无数的靶点来减少tau传播， 从而使疾病扩散到整个大脑。我们的研究旨在回答以下问题： 在体内从供体到受体tau赋予的tau结构，因此是我们的体内模型， 神经退行性变有效的研究tau传播（目的1）？如何翻译后的大量 与tau多晶型物形成相关的tau上的修饰（PTM）（目的2b），并且这些PTM是概括的吗 从供体到受体tau在体内（aim 2a）和体外（aim 3）？基因变化是什么 发生在患病脑细胞的回路中，这些变化是否会扩散到顺行和逆行， 逆行连接细胞（目标3）？使用新型体内和体外系统，包括定制的微流体细胞 培养设备，冷冻EM成像和分析，质谱和RNAseq，我们的目标是回答这些重要的问题。 问题，从而确定用于防止tau传播的未来目标。

Project summary/abstract. Tau protein accumulates into pathogenic deposits in many neurodegenerative diseases, including Alzheimer disease (AD) and some forms of Gerstmann-Sträussler-Scheinker disease (GSS). Using cryo-electron microscopy (cryo-EM) recent groundbreaking studies have determined the existence of multiple tau conformers, which may differ between tau diseases. The tau aggregates in AD and GSS contain all 6 isoforms of tau, and both have been ultrastructurally determined to contain paired helical filaments (PHFs). However in AD, there exists an ultrastructural polymorph to PHFs, comprised of the same amino acid sequence but a differing interface, named straight filaments (SFs). These SFs are not found in GSS, nor is it known why tau would fold into PHFs versus SFs in AD. This means that therapeutics designed to target specific tau conformers may not be suitable for all tau polymorphs within a disease. Numerous studies have demonstrated that tau acts in a ‘prion-like’ manner, templating the misfolding from pathogenic ‘donor’ to naïve ‘receiver’ tau, in both in vitro and in vivo models of tau diseases. However, how donor tau acts as a template to receiver tau is not yet known; the mechanism(s) of which would provide a myriad of targets to reduce tau propagation and thus disease dissemination throughout the brain. Our study aims to answer the following questions: is the structure of tau conferred from donor to receiver tau in vivo, and therefore are our in vivo models of neurodegeneration valid for investigating tau propagation (aim 1)? How are the numerous post-translational modifications (PTMs) on tau relevant to tau polymorph formation (aim 2b), and are these PTMs recapitulated from donor to receiver tau both in vivo (aim 2a) and in vitro (aim 3)? What are the gene changes that are occurring in a circuit of diseased brain cells, and are these changes spreading to both anterogradely and retrogradely connected cells (aim 3)? Using novel in vivo and in vitro systems including custom microfluidic cell culture devices, cryo-EM imaging and analysis, mass spectrometry and RNAseq, we aim to answer these vital questions and thus identify future targets for preventing tau propagation.