Patient-Based Structural Biology of Tauopathies and TDP-43 Proteinopathies using Cryo-Electron Microscopy and Mass Spectrometry

阿尔茨海默病（AD）中tau细丝的原子模型的开发已经打开了几个新的机会，包括鉴定高亲和力配体或抗体以检测AD tau细丝的能力（即，PET配体、小分子化合物、免疫疗法、生物标志物），并提供关于需要从建模角度概括的基本特征的明确指导。鉴于tau蛋白病是复杂的致病实体，在临床表现、病程和基础病理学方面具有显著异质性，因此开发中的工具必须能够检测/识别观察到的实际病理学。因此，当前项目的总体目标是表征tau蛋白病中tau蛋白丝的异质性，并利用在散发性和家族性疾病形式中定义tau和TDP-43丝形态的结构特征，以提供对发病机制和毒性的新见解。特别是，我们将评估和比较AD和慢性创伤性脑病（CTE）之间的tau丝异质性，并开发新的资源来检测和模拟这些不同的tau蛋白病中的tau蛋白。利用冷冻电子显微镜（cryo-EM）的类似方法也将用于解析额颞叶变性（FTLD）中的细丝结构，FTLD是AD后痴呆的第二大常见原因。由于FTLD的病理特征通常是tau（FTLD-tau）或TDP-43（FTLD-TDP）的异常沉积，因此我们将在散发性和家族性FTLD中开发tau和TDP-43细丝的原子模型。覆盖结构的见解与我们最近发现的新的翻译后修饰（PTM）的tau和TDP-43，我们将评估特定的修饰聚集倾向的贡献，利用冷冻EM，质谱，分子生物学和生物化学方法的组合。这些结果将指导资源的持续开发，以最好地检测和建模病理学的特定方面。

The development of an atomic model of tau filaments in Alzheimer’s disease (AD) has opened several new opportunities, including the ability to identify high-affinity ligands or antibodies to detect AD tau filaments (i.e., PET ligands, small molecule compounds, immunotherapy, biomarkers) and providing a clear directive about essential features that need to be recapitulated from a modeling perspective. Given that tauopathies are complex, pathogenic entities with significant heterogeneity in clinical presentation, disease course, and underlying pathology, it is essential that the tools under development are capable of detecting/recognizing the actual pathologies observed. As such, the overall goals of the current project are to characterize the heterogeneity of tau filaments across tauopathies, and to utilize structural features that define tau and TDP-43 filament morphology in sporadic and familial forms of disease to provide novel insight into pathogenesis and toxicity. In particular, we will assess and compare tau filament heterogeneity between AD and chronic traumatic encephalopathy (CTE) and develop novel resources to both detect and model tau in these distinct tauopathies. Similar methodology utilizing cryo-electron microscopy (cryo-EM) will also be employed to resolve filament structure in frontotemporal lobar degeneration (FTLD), which is the second most common cause of dementia after AD. As FTLD is usually characterized pathologically by the aberrant deposition of either tau (FTLD-tau) or TDP-43 (FTLD-TDP), we will develop atomic models of both tau and TDP-43 filaments in sporadic and familial forms of FTLD. Overlaying structural insights with our recent discovery of novel post-translational modifications (PTMs) of tau and TDP-43, we will assess the contribution of specific modifications to aggregation propensity, utilizing a combination of cryo-EM, mass spectrometry, molecular biology and biochemical approaches. These results will guide the continued development of resources to best detect and model particular aspects of pathology.