Tetrastigma hemsleyanum polysaccharides as natural inhibitors of platelet thrombosis via GPIIb/IIIa and MAPK pathways

Background: Thrombosis, driven by abnormal platelet activation and fibrin clot formation, is a key pathological basis of cardiovascular disorders. Polysaccharide-based agents, such as heparin, possess distinct antithrombotic activities. Tetrastigma hemsleyanum polysaccharide (THP) exhibits notable anti-inflammatory properties. However, its antithrombotic potential remains unexplored.

Purpose: This work intended to explore the antithrombotic and antiplatelet activities of THP5, a novel acidic glucuronic acid-containing galactomannan isolated from THP, and to elucidate its molecular targets and mechanisms of platelet interaction.

Methods: The antithrombotic activity of THP5 was tested in vivo using a mouse model of κ-carrageenan-induced thrombosis. In vitro platelet function assays determined its antiplatelet effects. Platelet protein targets were identified via pull-down, liquid chromatography-mass spectrometry (LC-MS/MS), and surface plasmon resonance (SPR) analyses. Comparative studies with the GPIIb/IIIa inhibitor tirofiban were performed in κ-carrageenan- and FeCl₃-induced thrombosis models. Proteomic profiling and bleeding risk assessments were conducted to investigate underlying mechanisms and safety.

Results: THP5 markedly reduced thrombus formation, attenuated inflammatory responses, and alleviated vascular injury in vivo. In vitro, it protected endothelial cells from LPS-induced damage and strongly inhibited platelet activation. GPIIb/IIIa was identified as a direct binding target of THP5, and proteomic analysis revealed modulation of the MAPK signaling pathway. Compared with tirofiban, THP5 demonstrated comparable efficacy with a lower bleeding risk.

Conclusion: THP5 exerts potent antithrombotic effects by directly targeting GPIIb/IIIa and modulating PKCα-MAPK-dependent platelet activation, supporting its potential as a safe and effective therapeutic candidate for thrombotic disorders.

GPIIb/IIIa; MAPK signaling; Platelet activation; THP5; Thrombosis.