Studying Aggregation in Neurodegenerative Disease using Synthetic Proteins

总结/摘要 蛋白质错误折叠和聚集形成原纤维是神经退行性疾病的常见特征，包括 阿尔茨海默病（AD）、帕金森病（PD）和相关疾病如PD伴痴呆（PDD）， 路易体痴呆（DLB）和多系统萎缩（MSA）。逆转或阻断蛋白质的药物 聚集与早期诊断相结合，为保留患者记忆的治疗提供了前景， 人格和身体机能的控制为了设计这样的药物和诊断剂，必须理解 神经元内的聚集和传播以“感染”新神经元的过程，以识别最 成像和干预的相关目标。我们的研究将集中在纤维状聚集体的积累， α-突触核蛋白（αS），通常与PD相关，以及tau，通常与AD相关。在许多情况下， 观察到αS和tau的共同病理学，模糊了这些疾病之间的经典界限， 更详细地了解聚合机制。Tau和αS都是亚稳定蛋白， 在病理条件下形成毒性低聚物和纤维状聚集体，包括异常氧化 应激或翻译后修饰（PTM）。然而，尽管进行了大量研究，tau蛋白共聚集的原因仍然不清楚。 在病理条件下仍不清楚。我们将研究tau纤维播种的分子基础， 选择αS纤维菌株。具体来说，我们将检验两个假设：1）αS纤维之间的直接物理相互作用 和tau单体导致tau聚集;和2）αS原纤维引起细胞信号传导和/或线粒体 间接触发tau聚集的功能。为了探索这些假设并确定它们的相对 影响，我们将进行基于细胞的研究，其中tau聚集与体外预形成的原纤维（PFF）接种 或从AD、PDD、DLB或MSA患者材料模板化的扩增的接种原纤维（ASF）。探头连接到 αS、tau和其他关键蛋白质将用于在荧光显微镜研究中跟踪定位， 物理接近使用光催化标记。这将使我们能够确定细胞中αS原纤维的相互作用 通过首先鉴定相关蛋白及其PTM，然后观察它们的 使用非干扰荧光氨基酸标签与活细胞成像共定位。我们的研究将吸引 AD相关疾病（ADRD）（通常以tau病理学为特征）与 突触核蛋白病、PDD、DLB和MSA。这些发现将为ADRD/PD提供关键的机制见解 合并症，并有可能确定新的治疗靶点，可以防止触发tau蛋白 病理学对αS聚集的反应。

Summary/Abstract Protein misfolding and aggregation to form fibrils are common features of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD) and related diseases such as PD with dementia (PDD), dementia with Lewy Bodies (DLB), and multiple system atrophy (MSA). Drugs that reverse or block protein aggregation, combined with early diagnosis, provide the prospect for a cure that preserves the patient's memories, personality, and control of bodily function. To design such drugs and diagnostic agents, one must understand the process of aggregation within neurons and propagation to “infect” new neurons in order to identify the most relevant targets for imaging and intervention. Our study will focus on the accumulation of fibrillar aggregates of α-synuclein (αS), commonly associated with PD, and tau, commonly associated with AD. In many cases, copathology of αS and tau is observed, blurring the classical boundaries between these diseases and demanding a more detailed understanding of aggregation mechanisms. Tau and αS are both meta-stable proteins that can form toxic oligomers and fibrillar aggregates under pathological conditions, including states of aberrant oxidative stress or post-translational modification (PTM). However, in spite of much study, the causes of tau coaggregation under pathological conditions remain unclear. We will investigate the molecular basis for tau fibril seeding by select αS fibril strains. Specifically, we will test two hypotheses: 1) Direct physical interactions between αS fibrils and tau monomers lead to tau aggregation; and 2) αS fibrils cause changes in cell signaling and/or mitochondrial function that indirectly trigger tau aggregation. In order to probe these hypotheses and determine their relative impact, we will perform cell-based studies in which tau aggregation is seeded with in vitro pre-formed fibrils (PFFs) or amplified, seeded fibrils (ASFs) templated from AD, PDD, DLB, or MSA patient material. Probes attached to αS, tau, and other key proteins will be used to track localization in fluorescence microscopy studies and identify physical proximity using photocatalytic labeling. This will allow us to determine how αS fibril interactions in cells lead to tau aggregation by first identifying the relevant proteins as well as their PTMs, and then observing their colocalization with live cell imaging using non-perturbing fluorescent amino acid tags. Our studies will draw important connections between AD related diseases (ADRDs), which typically feature tau pathology, and the synucleinopathies, PDD, DLB, and MSA. These findings will provide key mechanistic insight into ADRD/PD comorbidities and have the potential to identify new therapeutic targets that can prevent the triggering of tau pathology in response to αS aggregation.