Xinmailong Modulates Platelet Function and Inhibits Thrombus Formation via the Platelet αIIbβ3-Mediated Signaling Pathway

Abstract

<b>Background:</b> Xinmailong (XML), a bioactive composite extracted from <i>Periplaneta americana</i>, has been widely used to treat cardiovascular diseases such as congestive heart failure. However, it is unclear whether XML has antiplatelet and antithrombotic effects. <b>Methods:</b> The effects of XML on agonist-induced platelet aggregation, adhesion and spreading, granule secretion, integrin α II bβ3 activation, and thrombus formation were evaluated. Phosphorylation of Syk, PLCγ2, Akt, GSK3β, and MAPK signaling molecules was also studied on agonist-induced platelets. In addition, the antithrombotic effects of XML were observed <i>in vivo</i> using an acute pulmonary thrombosis mouse model. <b>Results:</b> XML dose-dependently inhibited <i>in vitro</i> platelet aggregation and granule secretion induced by thrombin, collagen, and arachidonic acid (AA). XML also greatly reduced platelet adhesion and spreading on both collagen- and fibrinogen-coated surfaces. Biochemical analysis revealed that XML inhibited thrombin-, collagen-, and AA-induced phosphorylation of Syk, PLCγ2, Akt, GSK3β, and MAPK. Additionally, XML significantly inhibited <i>in vivo</i> thrombus formation in a collagen-epinephrine-induced acute pulmonary thrombosis mouse model. <b>Conclusions and General Significance:</b> Here, we provide the first report showing that XML inhibits platelet function and that it possesses antithrombotic activity. This suggests that XML could be a potential therapeutic candidate to prevent or treat platelet-related cardiovascular diseases.