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

项目摘要/摘要。 在包括阿尔茨海默病在内的许多神经退行性疾病中，tau蛋白积聚到病原体沉积中。 阿尔茨海默病(AD)和一些形式的Gerstmann-Sträussler-Scheinker病(GSS)。使用低温电子 显微镜(低温电子显微镜)最近突破性的研究确定了多个tau的存在 构象，这在不同的牛磺酸疾病之间可能是不同的。AD和GSS中的tau聚集体包含所有6种亚型 这两种物质的超微结构都被确定含有成对的螺旋丝(PHF)。然而，在 AD，存在PHFS的超微结构多态，由相同的氨基酸序列组成，但 不同的界面，称为直丝(SFS)。这些SFS在GSS中没有发现，也不知道为什么tau 在AD中会合并为PHFS而不是SFS。这意味着针对特定tau的治疗方法 异构体可能并不适用于疾病中的所有tau多态。大量研究表明， Tau以一种类似普里恩的方式发挥作用，将致病的“供体”错误折叠成幼稚的“接受者”tau， 在体外和体内的tau病模型中。然而，供体tau如何作为受体tau的模板 目前尚不清楚；其机制(S)将提供无数的目标，以减少tau的传播和 因此，疾病在整个大脑中传播。我们的研究旨在回答以下问题： 在活体内从供体到受体的结构，因此我们的活体模型 神经退行性变对研究tau的传播有效(目标1)？众多的翻译后工作进展如何 与tau多态形成相关的tau修饰(Ptm)(目标2b)，这些ptm是否已概括？ 在体内(目标2a)和体外(目标3)从供体到受体tau？有哪些基因变化是 发生在病变脑细胞的环路中，这些变化是否同时蔓延到顺行和 逆行连接细胞(目标3)？使用包括定制微流控单元的新型体内和体外系统 培养设备、低温电磁成像和分析、质谱学和RNAseq，我们的目标是回答这些至关重要的问题 问题，从而确定未来防止tau传播的目标。

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.