FG-8mer抑制内源性因子X酶的分子机制及其机制相关的抗凝活性特征

Fucosylated glycosaminoglycan (FG) is a natural product with unique chemical structure, which can potently inhibit tenase (factor Xase, f.Xase) of the intrinsic coagulation pathway. The intrinsic f.Xase has been identified as a novel target for antithrombotic agents with low bleeding tendency, therefore, chemical and pharmacological study of FG is important both for academic value and potential application. During the past 40 years, although academic research on FG has achieved great progress, the precise chemical structure and molecular mechanism of f.Xase inhibition are the conundrums that remains to be solved. Our previous work has made a significant breakthrough in illuminating the precise structure of FG, and discovered that FG-8mer is the selective f.Xase inhibitor with the simplest chemical structure so far known. Based on these, this project is intended to study more comprehensively and systemically to reveal the molecular mechanism of f.Xase inhibition by FG-8mer, using the technical methods, such as enzymic kinetics, protein-compound interaction, fluorescence method and FRET for protein structural analysis, and analysis of co-crystal f.IXa and FG-8mer. Additionally, we will further explore the anticoagulant and antithrombotic characteristic of FG-8mer associated with the molecular mechanism, as well as evaluate the potential application value of f.Xase inhibitor. This study will provide useful information and strategy for the discovery of novel f.Xase inhibitors.

岩藻糖化糖胺聚糖(FG)是化学结构特殊的天然产物，具有强效内源性因子X酶(f.Xase)抑制活性。由于内源性f.Xase是新的低出血倾向抗血栓药物的靶点，FG化学及药理学研究具有重要的学术价值和应用价值。持续近40年的FG研究成果丰硕，但其确切化学结构和抑制f.Xase活性的分子机制是仍尚待逾越的关键性学术难题。本课题前期在阐明FG确切结构研究中取得重要突破，发现了目前所知的化学结构最简单的选择性f.Xase抑制剂FG-8mer。在此条件下，本课题拟采用酶促动力学、靶蛋白相互作用、荧光及FRET法蛋白结构分析以及靶蛋白共结晶制备等方法，希望通过全面系统的分析研究，清晰揭示FG-8mer强效抑制f.Xase的分子机制，解决FG药理学关键学术问题，为f.Xase抑制剂的发现提供新的策略思路；并进一步研究FG-8mer分子机制相关的抗凝抗血栓活性特点，分析和评价f.Xase抑制剂的潜在应用价值。

岩藻糖化糖胺聚糖(FG)是化学结构特殊的天然产物，具有强效内源性因子X酶(f.Xase)抑制活性。由于内源性f.Xase是新的低出血倾向抗血栓药物的靶点，FG化学及药理学研究具有重要的学术价值和应用价值，本课题前期在阐明FG确切结构研究中，发现目前所知的化学结构最简单的选择性f.Xase抑制剂为FG-8mer。. 本项目主要研究内容是揭示FG-8mer作为内源性f.Xase抑制剂的靶点作用的分子机制、其抗凝、抗血栓活性特点、以及所见抗凝抗血栓活性特点与其靶点机制的药理学逻辑关联。. 本项目通过酶学、大分子相互作用、荧光共振能量转移分析等技术方法研究揭示，FG-8mer以部分非竞争模式抑制f.Xase，其分子机制是高亲和力结合f.Xase所含酶活蛋白f.IXa(结合于f.IXa蛋白外位点)，继而阻碍f.IXa与f.VIIIa正确组装成为功能性的酶复合物。. 药理学分析揭示，FG-8mer具有依赖于抑制f.Xase分子机制的抗凝活性特点，即选择性抑制内源性凝血途径；FG-8mer可以显著抑制内源性凝血激活剂及微量组织因子诱导的静脉血栓形成活性，对大量组织因子暴露所致的止血功能相关的血栓形成影响较弱，反映出清晰的“靶点”--“抗凝”--“抗血栓”活性的药理学逻辑关系，并且呈现出与此逻辑关系密切相关的低出血倾向的活性特点。. 本项目研究的科学意义在于通过系统和细致的学术研究阐明FG寡糖类成分作用于内源性f.Xase的分子机制，并且清晰揭示其药理学活性特点与其靶点机制之间的药理学逻辑关系；所述研究不仅为新靶点机制的活性成分发现提供参考，还可以为进一步认识凝血系统的生理及病理调控机制提供有效的药理学探针。.