Oligosaccharide Blocks PAR1 (Proteinase-Activated Receptor 1)-PAR4–Mediated Platelet Activation by Binding to Thrombin Exosite II and Impairs Thrombosis

作者：Sujuan Li, Weili Wang, Lisha Lin, Lian Yang, Ying Cai, Xing‐Zhi Yang, Taocui Zhang, Chuang Xiao, Hui Yan, Na Gao, Jinhua Zhao · 发表于：Arteriosclerosis Thrombosis and Vascular Biology · 年份：2022 · DOI：10.1161/atvbaha.122.318085 · 被引用次数：9 · 研究领域：Platelet Disorders and Treatments、Blood Coagulation and Thrombosis Mechanisms、Protease and Inhibitor Mechanisms

Background: Inappropriate activation and aggregation of platelets can lead to arterial thrombosis. Thrombin is the most potent platelet agonist that activates human platelets via two PARs (proteinase-activated receptors), PAR1 and PAR4. The aim is to study the activity and mechanism of an oligosaccharide HS-11 (the undecasaccharide, derived from sea cucumber Holothuria fuscopunctata ) in inhibiting thrombin-mediated platelet activation and aggregation and to evaluate its antithrombotic activity. Methods: Platelet activation was analyzed by detecting CD62P/P-selectin expression using flow cytometry. The HS-11-thrombin interaction and the binding site were studied by biolayer interferometry. Intracellular Ca 2+ mobilization of platelets was measured by FLIPR Tetra System using Fluo-4 AM (Fluo-4 acetoxymethyl). Platelet aggregation, thrombus formation, and bleeding Assay were assessed. Results: An oligosaccharide HS-11, depolymerized from fucosylated glycosaminoglycan from sea cucumber Holothuria fuscopunctata blocks the interaction of thrombin with PAR1 and PAR4 complex by directly binding to thrombin exosite II, and completely inhibits platelet signal transduction, including intracellular Ca 2+ mobilization and protein phosphorylation. Furthermore, HS-11 potently inhibits thrombin-PARs–mediated platelet aggregation and reduces thrombus formation in a model of ex vivo thrombosis. Conclusions: The study firstly report that the fucosylated glycosaminoglycan oligosaccharide has an...