Abstract 11072: Profiling of a Platelet Proteome Discriminates Between Subjects and the Effects of Antiplatelet Agents Alone and in Combination

Abstract

Protein profiling of biological samples provides an integrated measurement of genetic, environmental and drug effects. We examined the response to a number of antiplatelet drugs alone and in combination on the human platelet secreteome following stimulation with thrombin. The drugs included a P2Y12 antagonist (PSB0739) and a PAR-1 antagonist (RWJ56110) at concentration (10nM) that blocked the platelet responses to their respective agonists, and aspirin (10microM). Thrombin (1U/ml) was used to stimulate aggregation and secretion of washed platelets despite the presence of the drugs. Platelets were obtained from healthy donors and drugs added in vitro. The proteome profile was determined by label-free quantitative mass spectrometry (Q Exactive and MaxQuant software). The profile was markedly different between individuals (n=3) but it was similar for the same individual over 3 separate samples obtained weeks apart. The addition of the antiplatelet agents showed a similar strong individual clustering of all proteins (>1,000). Cluster analysis of the 270 proteins that changed with drug showed marked differences between drugs although there was no impact on platelet aggregation. Similarly, combinations of 2 or 3 drugs demonstrated distinctive clustering of changes in the protein profile. Functional ontology of the proteome showed marked differences between drugs with very distinctive patterns. Similarly, drugs differed clearly in their effects on discrete functional protein clusters, such as ‘coagulation proteins’. Our findings suggest that individuals have distinct platelet proteomes (‘proteome barcode’) that remain evident in the presence of drug. Despite this, antiplatelet drugs exhibit distinct effects on the platelet proteome, when applied alone and in combination. The profiling of the platelet proteome better discriminates the effects of antiplatelet drugs than is possible with platelet aggregation and may help tailor therapy more effectively.