Bioprocess Engineering Department, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran; Department of Neurology, School of Medicine, Technical University of Munich, Munich, Germany; Department of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.
Bioprocess Engineering Department, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran; Interdisciplinary Nanoscience Centre (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
Int J Biol Macromol. 2020 Jul 15;155:543-550. doi: 10.1016/j.ijbiomac.2020.03.238. Epub 2020 Mar 31.
The α-synuclein (αSN) amyloid fibrillization process is known to be a crucial phenomenon associated with neuronal loss in various neurodegenerative diseases, most famously Parkinson's disease. The process involves different aggregated species and ultimately leads to formation of β-sheet rich fibrillar structures. Despite the essential role of αSN aggregation in the pathoetiology of various neurological disorders, the characteristics of various assemblies are not fully understood. Here, we established a fluorescence-based model for studying the end-parts of αSN to decipher the structural aspects of aggregates during the fibrillization. Our model proved highly sensitive to the events at the early stage of the fibrillization process, which are hardly detectable with routine techniques. Combining fluorescent and PAGE analysis, we found different oligomeric aggregates in the nucleation phase of fibrillization with different sensitivity to SDS and different structures based on αSN termini. Moreover, we found that these oligomers are highly dynamic: after reaching peak levels during fibrillization, they decline and eventually disappear, suggesting their transformation into other αSN aggregated species. These findings shed light on the structural features of various αSN aggregates and their dynamics in synucleinopathies.
α-突触核蛋白（αSN）的淀粉样纤维形成过程是与各种神经退行性疾病中神经元丧失相关的关键现象，最著名的是帕金森病。该过程涉及不同的聚集物种，最终导致富含β-折叠的纤维状结构的形成。尽管 αSN 聚集在各种神经紊乱的发病机制中起着重要作用，但各种聚集体的特征尚不完全清楚。在这里，我们建立了一种基于荧光的模型来研究αSN 的末端部分，以解析纤维形成过程中聚集物的结构方面。我们的模型对纤维形成过程早期的事件非常敏感，而常规技术几乎无法检测到这些事件。结合荧光和 PAGE 分析，我们在纤维形成的成核阶段发现了不同的寡聚体聚集物，它们对 SDS 的敏感性不同，基于αSN 末端的结构也不同。此外，我们发现这些寡聚体具有高度的动态性：在纤维形成过程中达到峰值水平后，它们会下降并最终消失，表明它们转化为其他 αSN 聚集物种。这些发现揭示了突触核蛋白病中各种αSN 聚集物的结构特征及其动态性。
