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

Autor: Sujuan Li, Weili Wang, Lisha Lin, Lian Yang, Ying Cai, Xingzhi Yang, Taocui Zhang, Chuang Xiao, Hui Yan, Na Gao, Jinhua Zhao
Rok vydání: 2023
Předmět:
Zdroj: Arteriosclerosis, Thrombosis, and Vascular Biology. 43:253-266
ISSN: 1524-4636
1079-5642
DOI: 10.1161/atvbaha.122.318085
Popis: 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 antiplatelet activity by binding to thrombin exosite II, and demonstrates that thrombin exosite II plays an important role in the simultaneous activation of PAR1 and PAR4, which may be a potential antithrombotic target for effective treatment of arterial thrombosis.
Databáze: OpenAIRE
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