MiR-146a Regulates Neutrophil Extracellular Trap Formation That Predicts Adverse Cardiovascular Events in Patients With Atrial Fibrillation

Objective Atrial fibrillation (AF) patients experience adverse cardiovascular events (ACEs) despite anticoagulant therapy. We reported that rs2431697 of miR-146a, a negative regulator of inflammation, predicts ACEs in patients with AF. The relationship between neutrophil extracellular traps and thrombogenesis is known. Thus, our aim was to evaluate the role of neutrophil extracellular trap compounds as prognostic markers of ACEs in AF and to study whether miR-146a affects NETosis. Approach and Results We included 336 steadily anticoagulated AF patients with a median follow-up of 7.9 years (interquartile range, 7.3-8.1) and 127 healthy subjects. The reviewed ACEs included stroke (ischemic/embolic), acute coronary syndrome, acute heart failure, and global or vascular death. We quantified cell-free DNA and NE (neutrophil elastase) at diagnosis. Rs2431697 was genotyped. Neutrophils from human and mice were seeded to analyze shed cell-free DNA and H3cit (citrullinated histone 3) after activation. In human plasmas, higher NE levels (>55.29 ng/mL), but not cell-free DNA, were independently associated with higher risk of all-cause mortality (hazard ratio, 2.24; 95% CI, 1.36-3.68), cardiovascular mortality (hazard ratio, 4.77; 95% CI, 1.11-20.47), and composite cardiovascular events (hazard ratio, 1.84; 95% CI, 1.01-3.76). In patients, NE levels were associated with rs2431697 (TT: 51.822.73 versus CC: 40.01 +/- 3.05 ng/mL; P=0.040). In vitro, both human (TT for rs2431697) and miR-146a(-/-) mice neutrophils yielded higher levels of cell-free DNA and H3cit than CC or wild-type cells, respectively. Conclusions NE activity can provide new ACE prognostic information in AF patients. These findings provide evidence of a potential role of miR-146a in neutrophil extracellular trap generation and cardiovascular risk in AF.