Abstract 17411: De Novo Protein Synthesis of Alpha-Toxin Activated Platelets

Abstract

Introduction: Endovascular infections with bacteria are often devastating with subsequent high morbidity and mortality. Exo- and or endotoxins of bacteria can activate endothelial cells, leukocytes and platelets. Platelets are first line defence they accumulate at sites of vascular injury or infection. Platelet activation is a necessary step in thrombus formation. Nevertheless, stimulation of platelets will result in de novo protein synthesis despite missing nucleus since platelets armed with translational equipment. Methods: In the present study we determined the effect of staphylococcus aureus α-toxin on platelet activation and de novo protein synthesis analysed with 2-D gels, proteomics and phosphorylation analysis. Results: α-toxin induced platelet activation resulted in modulation of de novo protein synthesis of DJ-1 Protein, ras suppressor protein1, PLEK protein, fumaryl aceto acetase sowie das coronin actin binding protein. This synthesis was time- and concentration-dependent and was markedly increased when platelets adhered to collagen or fibrinogen and required ligation of α IIb β 3 . Accumulation of protein synthesis in platelets was blocked by global translational inhibitors and attenuated by inhibitors that regulate signalling through the mammalian Target of Rapamycin (mTOR). In addition with phosphorylation analysis we were able demonstrate modulation of threonine phosphorylation of fumaryl aceto acetase, phosphor threonin signal of coronin actin binding protein, phosphorylation of peroxiredoxin-6, phosphorylation of tropomyosin-2, phosphothreonin signal of H + transporting two sector ATPase upon α-toxin stimulation. Conclusion: Interactions with staphylococcus aureus α-toxin and platelets might lead to their activation and de novo protein synthesis. These results suggest that platelets have an important role in inflammation besides their aggregating duties in inflammatory disease.