氧甾酮影响淀粉样蛋白质聚集及其抑制过程的分子机理

Protein misfolding can induce its aggregation and deposition, which is the main reason of many conformational diseases, such as Alzheimer’s disease, Parkinson’s disease, etc. It has been shown that many metabolites, especially the cholesterol derivatives, can accelerate the misfolding/aggregation of a number of proteins. However, the existing strategies for inhibiting protein aggregation were proposed without considering the impact of metabolites, severely blocking the investigation of aggregation mechanisms and the development of efficient inhibitor. In this project, oxysterol is selected as the respective metabolite, and its working mechanisms in the aggregation of amyloid proteins and the inhibition of small-molecule inhibitors will be studied systematically, including binding sites and their distribution, interaction type, as well as the effects on the conformational transition, aggregate morphology, aggregation pathway, cytotoxicity, etc. Amyloid β-peptide, islet amyloid polypeptide and insulin are chosen as the model amyloid protein. Epigallocatechin-3-gallate and curcumin are chosen as the model inhibitor. Comprehensive kinetics, thermodynamics, biological assay and molecular dynamics simulations methods will be used in this project. Furthermore, based on these results, the theory of amyloid proteins aggregation and its inhibition in the presence of metabolites will be proposed. This theory will guide the design and development of novel efficient inhibitors suitable for the organism condition, and finally form the scientific and technological bases for the new strategy to prevent and treat conformational diseases.

由蛋白质错误折叠导致的蛋白质聚集沉积，是引发阿尔茨海默症、帕金森症等多种蛋白质构象病的主要原因。研究表明，机体代谢物特别是胆固醇代谢物会加速蛋白质聚集，但现有的抑制蛋白质聚集策略均未考虑机体代谢物对蛋白质聚集的影响，这会严重阻碍蛋白质聚集机理的解析和高效抑制剂的开发。因此，本项目将以氧甾酮作为代表性代谢物，利用热力学、动力学、生物学实验研究和分子模拟分析相结合的方法，从结合位点及其分布、作用力类型、蛋白质构象转变、聚集体形态、聚集路径、细胞毒性等方面，系统研究氧甾酮在β-淀粉样多肽、胰岛淀粉样多肽和胰岛素等淀粉样蛋白质聚集以及小分子抑制剂抑制其聚集过程中的作用和分子机理；在此基础上，提出代谢物存在的机体环境条件下淀粉样蛋白质的聚集及其抑制剂的抑制聚集理论。本项目研究成果将指导符合机体环境条件下高效抑制剂的设计和开发，最终为蛋白质构象病的预防和治疗新策略的设计和实施提供理论基础和技术支撑。

由蛋白质错误折叠导致的蛋白质聚集沉积，是引发阿尔茨海默症、2型糖尿病、帕金森症等多种蛋白质构象病的主要原因。研究表明，胆固醇代谢物氧甾酮、金属离子等机体代谢物会加速蛋白质聚集，但现有的抑制蛋白质聚集策略均未考虑机体代谢物对蛋白质聚集的影响，严重阻碍蛋白质聚集机理的解析和高效抑制剂的开发。针对此关键问题，本项目系统研究机体代谢物在β-淀粉样多肽（Aβ）、胰岛淀粉样多肽IAPP等淀粉样蛋白质聚集及其抑制过程中的作用和分子机理，综合利用利用热力学、动力学、生物学实验研究和分子模拟分析相结合的方法，揭示了关键作用位点（包括第10位酪氨酸残基两端的亲和位点、13位和14位的组氨酸残基、疏水核心、带电基团等）；基于关键作用位点提出了代谢物存在的机体环境条件下淀粉样蛋白质的聚集及其抑制剂的抑制聚集理论（以及作用位点-促进/抑制聚集理论）；在此理论基础上，对现有抑制剂进行针对性的修饰改造，获得了多种新型抑制剂（LK7-HH和cLK7等）和抑制策略，实现了代谢物存在的高效抑制和解毒；总结了高效聚集抑制剂理性设计的途径和思路，指导符合机体环境的淀粉样蛋白质聚集抑制策略开发。本项目研究成果不但深化了对淀粉样蛋白质聚集及其抑制过程的理论认识，更为蛋白质构象病的预防和治疗新策略的设计和实施提供理论与技术指导。研究成果发表SCI论文5篇，另有1篇SCI论文正在出版中，2篇SCI论文正在审稿中。