Abstract 198: Activation of Human Platelets by Staphylococcus aureus Secreted Protease Staphopain A
Staphylococcus aureus is the leading aetiological agent of infective endocarditis (IE). The pathogen can induce the activation of platelets, resulting in aggregation and thrombus formation, which are regarded as important steps in the pathogenesis of IE. In this study, we demonstrate that staphopain A, a cysteine protease secreted by S. aureus, induces the aggregation of human platelets. The presence of staphopain A in the supernatant of S. aureus confers an ability to activate platelets, in addition to the actions of alpha haemolysin also released by the pathogen. Staphopain A platelet agonist activity was inhibited by addition of the specific inhibitor staphostatin A, implicating its protease activity in the agonism. Concentrations of staphopain A that were insufficient to induce platelet aggregation caused increased platelet binding to collagen. Using specific antagonists, protease-activated receptors 1 and 4 were shown to be responsible for mediating staphopain A induced activation of platelets.
Author Disclosures: S.R. Clarke: None.
- © 2014 by American Heart Association, Inc.