The zebrafish model tackles anti-P2Y12 variability in humans: a translational approach.

Antiplatelet drugs are a pillar in the treatment strategy to prevent ischemic events in patients with cardiovascular disease. However, the action of existing therapies is nonuniform, and the causative mechanism for this variability remains poorly understood. The differences in the microRNA (miRNA) profiles among individuals have been suggested to impact platelet reactivity and treatment outcomes. In several previous clinical reports, miR-150 has been associated with platelet function variability and cardiovascular events. Therefore, we initiated our analysis by examining the mechanistic role of miR-150 in platelet function. We employed transgenic zebrafish larvae that were designed to specifically increase miR-150 expression in thrombocytes. Laser-induced caudal vein injury in these animals led to the formation of a smaller thrombus and decreased thrombocyte accumulation. RNA sequencing of miR-150-overexpressing thrombocytes identified a downregulated transcript that encoded microtubule-associated serine/threonine kinase-like (mastl), a key regulator of P2Y12 receptor downstream signaling. Overnight treatment of the transgenic fish with clopidogrel, a P2Y12 inhibitor, showed decreased thrombus formation in the control but not in the miR-150-overexpressing animals. This phenotype was reversed by overexpressing mastl. Next, we used a Vasodilator-Stimulated Phosphoprotein (VASP) phosphorylation assay to show that MASTL deficiency partially protects human platelets from P2Y12 inhibition. Finally, using miRNA:mRNA interaction predictors and experimental assays, we identified MASTL-targeting miRNAs in humans, specifically miR-17-5p and miR-106a-5p, which were significantly upregulated in a population of patients who were clopidogrel resistant. Our studies therefore support a model in which miR-150 in zebrafish and miR-17-5p or miR-106a-5p in humans modulate MASTL expression, which, in turn, alters VASP phosphorylation and platelet sensitivity to P2Y12 inhibition.