Thrombin receptor agonist peptide decreases thrombomodulin activity in cultured human umbilical vein endothelial cells

Recently, it has been shown that the N-terminal peptide from a new type of Thrombin receptor exhibits Thrombin receptor agonist activity. We examined the effects of this synthetic Thrombin receptor against peptide (SFLLRNPNDKYEPF, TRAP) on human umbilical vein endothelial cells (HUVECs). TRAP induced rapid morphological changes in HUVECs, with marked increase in the release of prostacyclin, endothelin, platelet activating factor, tissue type plasminogen activator, and plasminogen activator inhibitor-1. Incubation of cells with TRAP also induced a rapid decrease in cell-surface thrombomodulin. Thus, activation of the newly described Thrombin receptor may alter their role in the hemostatic pathway.