Differentiation and characterization of conformational alpha-synuclein strains associated with Parkinson's disease and related synucleinopathies

突触核蛋白病是一组以错误折叠为特征的神经退行性疾病， 错误折叠的α-突触核蛋白（αSyn）的聚集和积累，包括帕金森氏病 疾病（PD）、多系统萎缩（MSA）和路易体痴呆（DLB）。尽管 共享相同的病理蛋白质，不同的临床和病理表型通常 在不同的突触核蛋白病中观察到。开发有效治疗方法的主要障碍之一 突触核蛋白病的主要原因是在脑损伤发生前缺乏早期诊断， 疾病的症状。在临床上，区分一些 突触核蛋白病（例如PD和MSA），尤其是在疾病的早期阶段。这是一 这是一个重要问题，因为这些疾病有不同的预后和治疗模式。 最近，我们开发了蛋白质错误折叠循环扩增（PMCA，也称为RT- QuIC）技术，用于高灵敏度和特异性检测生物体液中的αSyn寡聚体， 受突触核蛋白病影响的患者。αSyn-PMCA利用朊病毒样接种机制， 循环放大蛋白质错误折叠的过程，使小的 大量的αSyn寡聚体，便于检测。我们有证据表明 来自患有PD和MSA的患者的CSF样品的αSyn-PMCA可以实验性地与来自患有PD和MSA的患者的CSF样品的αSyn-PMCA分离。 杰出的因此，我们假设αSyn聚集体与不同的 突触核蛋白病对应于αSyn的不同构象菌株/亚菌株， 用αSyn-PMCA忠实地扩增，产物可通过其生化特性进行区分， 结构和生物学特性。在这项研究中，我们的主要目标是检测，区分和 从生物体液和脑组织中扩增微量的αSyn菌株/亚菌株， 通过体外接种/扩增试验检测患有突触核蛋白病的患者，并表征这些患者 使用各种生化、结构和生物学技术分析αSyn构象聚集体。 在此获得的发现将为发展生物化学测试奠定基础 通过敏感和特异性检测不同的αSyn来鉴别诊断突触核蛋白病 菌株/亚菌株，这将有助于患者分层，临床试验的目标招募， 个性化治疗。

Synucleinopathies are a diverse group of neurodegenerative diseases characterized by misfolding, aggregation and accumulation of misfolded alpha-synuclein (αSyn) which include Parkinson‘s disease (PD), multiple system atrophy (MSA) and dementia with Lewy bodies (DLB). Despite sharing the same pathological protein, different clinical and pathological phenotypes are typically observed in different synucleinopathies. One of the main obstacles to develop effective treatments for synucleinopathies is the lack of an early diagnosis before the onset of brain damage and clinical symptoms of the disease. Clinically, it is very challenging to discriminate between some of the synucleinopathies (e.g. PD and MSA), especially at early stages of the disease. This is an important problem because these diseases have different prognosis and modes of treatment. Recently, we developed the protein misfolding cyclic amplification (PMCA, also known as RT- QuIC) technology for highly sensitive and specific detection of αSyn oligomers in biological fluids of patients affected by synucleinopathies. αSyn-PMCA utilizes the prion-like seeding mechanism to cyclically amplify the process of protein misfolding, enabling the efficient amplification of small quantities of αSyn oligomers, facilitating their detection. We have evidence that the product of αSyn-PMCA coming from CSF samples of patients affected by PD and MSA can be experimentally distinguished. Thus, we hypothesize that αSyn aggregates associated with different synucleinopathies correspond to different conformational strains/ sub-strains of αSyn that can be faithfully amplified by αSyn-PMCA and the product can be differentiated by their biochemical, structural and biological properties. In this study, our main goal is to detect, differentiate and amplify minute amounts of αSyn strains/ sub-strains from biological fluids and brain tissue of patients with synucleinopathies by an in-vitro seeding/ amplification assay, and characterize these αSyn conformational aggregates using various biochemical, structural, and biological techniques. The findings obtained here will lay the foundation towards the development of a biochemical test for differential diagnosis of synucleinopathies by sensitive and specific detection of different αSyn strains/sub-strains, which will help in patients’ stratification, target enrollment for clinical trial and personalized treatment.