Comparative platelet releasate proteome profiling of acute coronary syndrome versus stable coronary artery disease

Upon activation, platelets release a host of soluble and vesicular signals, collectively termed the ‘platelet releasate’ (PR). The contents of this PR play a significant role in haemostasis, inflammation, and pathologic sequelae. Despite this, proteomic studies investigating the PR in coronary artery disease have not been performed. We undertook a comparative label-free quantitative (LFQ) proteomic profiling of the 1U/ml thrombin-induced PR from 13 acute coronary syndrome (ACS-STEMI) versus 14 stable angina pectoris patients using a tandem mass spectrometry approach. We identified differentially released platet proteins including tetranectin (CLEC3B), protein disulfide-isomerase-A3 (PDIA3), coagulation factor V (F5) and fibronectin (FN1). Strikingly, all 9 differential proteins were associated with the GO cellular component term ‘extracellular vesicle’ and reduced levels of EVs were detected in plasma of ACS-STEMI patients. Network analysis revealed 3 PR proteins either reduced (F5; FN1) or absent (CLEC3B) in ACS-STEMI patients, which are strongly connected to both the clotting cascade and major druggable targets on platelets. This moderated signature highlights the possible basis of platelet dysfunction in ACS-STEMI and may prove useful for non-invasive risk assessment of the progression of coronary artery disease.