Platelet miR-144-5p regulates COX-1/2 expression and modulates aspirin response in patients with cardiometabolic risk

Interindividual variability in response to low-dose aspirin (acetylsalicylic acid; ASA) contributes to residual platelet activation and thrombotic risk. Platelet microRNAs (miRNAs) may modulate ASA pharmacodynamics, but their mechanistic role remains unclear. We investigated whether platelet miR-144-5p regulates cyclooxygenase 1/2 (COX-1/2) expression and modulates ASA response in patients with cardiometabolic disease. Two hundred ASA- treated patients were stratified into tertiles of serum thromboxane B2 (sTXB2) slope, an ex vivo marker of COX-1 recovery. Platelet and extracellular vesicle (EV) miR-144-5p levels were quantified by quantitative reverse transcription polymerase chain reaction and correlated with biochemical and clinical variables. Functional studies were performed in megakaryocytic (DAMI cells) and endothelial (human umbilical vein endothelial cells [HUVECs]) cells transfected with miR-144-5p mimics or inhibitors to assess COX-1/2 regulation. Patients with poor ASA response (third tertile of sTXB2 slope) exhibited reduced platelet miR-144-5p (P = .027) and higher COX-1 mRNA/protein levels (P ≤ .027), whereas miR-144-5p was enriched in platelet-derived EVs. Platelet miR-144-5p was inversely correlated with sTXB2 (ρ = −0.235, P = .007) and COX-1/2 mRNA expression. In DAMI cells, ASA exposure upregulated miR-144-5p cells; in addition, miR-144-5p overexpression suppressed, and inhibition enhanced, COX-1 protein levels. Similar effects were observed in HUVECs, where miR-144-5p downregulated both COX-1 and COX-2. Among our patients, platelet miR-144-5p levels were lower in those with obesity, dyslipidemia, and metabolic dysfunction–associated steatotic liver disease, conditions known to affect aspirin response. Platelet miR-144-5p directly regulates COX-1/2 expression in vitro and is associated with interindividual variability in ASA response. Low platelet miR-144-5p level identifies patients with accelerated COX-1 recovery and residual thromboxane generation, providing a potential mechanistic framework for precision antiplatelet therapy and miRNA-targeted interventions.