Comparative analysis of platelet-derived microparticles reveals differences in their amount and proteome depending on the platelet stimulus

Platelet-derived microparticles (PMP) are elevated in a number of disorders (e.g. cardiovascular disease and cancer). In the present study, we have carried out a high-resolution 2-DE-based proteomic analysis of PMP originated following platelet activation with different stimulus. Flow cytometric analysis revealed a higher average number of microparticles when platelets are activated with shear (1800 s(-1)) compared to 0.5 U/mL thrombin. Regarding the proteomic analysis, 30 protein features were found to be differentially regulated between shear and thrombin groups in the pI 4-7 range, from which 28 were successfully identified by MS, corresponding to 26 open-reading frames. Signaling proteins constituted the major functional group, including membrane receptors, and adapters. Ingenuity Pathways Analysis (IPA) software revealed that 21 of the 26 differentially regulated unique proteins identified are part of a common network related to cell assembly and organization and cell morphology. Western blotting analyses confirmed that Dok-2 and the integrin alpha 6 are differentially regulated in PMP depending on the platelet stimulus. Interestingly, both proteins participate in mechanisms regulating angiogenesis so could be part of PMP regulation of endothelial cells function. In conclusion, this study shows that platelets shed microparticles in different amounts and with a different proteome depending on the stimulus. This article is part of a Special Issue entitled: Integrated omics. (C) 2012 Elsevier B.V. All rights reserved.