Abstract Body (Do not enter title and authors here): Background: Coronary endothelial dysfunction plays a key role in the pathogenesis of cardiovascular events. In the setting of myocardial infarction (MI), activated platelets release prothrombotic and proinflammatory factors, contributing to vascular injury and dysfunction. However, the effect of platelets on coronary endothelial function during MI is not fully understood. We investigated the effect of platelets from patients with MI on cultured coronary endothelial cells in vitro.
Methods: Platelet RNA sequencing was performed and platelet releasates were obtained from patients with acute MI (n = 24) and control patients with stable coronary artery diseases (n = 22) who were referred to invasive coronary angiography. Human coronary artery endothelial cells (HCAECs) were treated with platelet releasates for 6 hours and collected for RNA sequencing. Mitochondrial function of treated HCAECs was evaluated by live cell imaging and JC-1 assay with flow cytometry.
Results: Overall, 1832 genes were differentially expressed in the transcriptome of HCAECs treated with MI (vs control) platelets (p < 0.05). Ingenuity pathway analysis found that mitochondrial dysfunction (up-regulated; p = 1.7 × 10^-8) and oxidative phosphorylation (down-regulated; p = 7.2 × 10^-8) were the top two altered pathways in HCAECs treated with MI platelets (Figure A & B). Consistently, live cell imaging with MitoTracker Red staining and JC-1 assay by flow cytometry showed MI (vs. control) platelet releasate-treated HCAECs had reduced mitochondrial membrane potential. By correlating the differentially expressed platelet genes in MI vs controls, we identified the platelet gene cluster that induced endothelial cell mitochondrial dysfunction, which was enriched in coagulation, platelet activation, and platelet degranulation (Figure C).
Conclusions: Platelets-derived mediators from patients with MI induce altered endothelial cell gene expression and mitochondrial dysfunction.