Identification of a circulating microvesicle protein network involved in ST-elevation myocardial infarction

Membrane microvesicles (MVs) are released from activated cells, most notably platelets, into the circulation. They represent an important mode of intercellular communication, and their number is increased in patients with acute coronary syndromes. We present here a differential proteomic analysis of plasma MVs from ST-elevation myocardial infarction (STEMI) patients and stable coronary artery disease (SCAD) controls. The objective was the identification of MVs biomarkers/drug targets that could be relevant for the pathogenesis of the acute event. Proteome analysis was based on 2D-DIGE, and mass spectrometry. Validations were by western blotting in an independent cohort of patients and healthy individuals. A systems biology approach was used to predict protein-protein interactions and their relation with disease. Following gel image analysis, we detected 117 protein features that varied between STEMI and SCAD groups (fold change cut-off >= 2; p<0.01). From those, 102 were successfully identified, corresponding to 25 open-reading frames (ORFs). Most of the proteins identified are involved in inflammatory response and cardiovascular disease, with 11 ORFs related to infarction. Among others, we report an up-regulation of alpha 2-macroglobulin isoforms, fibrinogen, and viperin in MVs from STEMI patients. Interestingly, several of the proteins identified are involved in thrombogenesis (e.g. alpha 2-macroglobulin, and fibrinogen). In conclusion, we provide a unique panel of proteins that vary between plasma MVs from STEMI and SCAD patients and that might constitute a promising source of biomarkers/drug targets for myocardial infarction.