bioRxiv · Jan 13, 2026
Exercise-Induced Epoxy-Eicosanoids Promote Cardiomyocyte Proliferation and Post-Infarction Repair via NR4A1
By Wang j, Zhang Z, Bian Y et al.
BACKGROUNDMyocardial infarction (MI) causes irreversible cardiomyocyte loss that exceeds the adult hearts regenerative capacity, leading to adverse remodeling and heart failure. While exercise provides cardiovascular protection, the mechanisms underlying exercise-induced cardiac repair remain unclear. METHODSPlasma levels of free fatty acids and polyunsaturated fatty acid metabolites were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). RNA sequencing was performed to identify differentially expressed genes and enriched pathways. NR4A1 was knocked down in mice via tail vein injection of AAV9 carrying shRNA targeting NR4A1 (AAV9-shNR4A1). The role of 17,18-EEQ was evaluated by continuous subcutaneous infusion via osmotic minipump; the involvement of the cAMP-PKA-CREB axis was assessed using specific pharmacological inhibitor. Molecular analyses included ELISA, immunofluorescence staining, QPCR, and western blotting. Additionally, clinical samples were collected from 36 endurance-trained athletes and 30 sedentary individuals (age 18-22, male) for comparative analysis. RESULTSHere we demonstrate that preventive aerobic training promotes post-MI cardiomyocyte proliferation and confers cardioprotection by reducing fibrosis area and improving cardiac function. Targeted lipidomics revealed that exercise elevates circulating epoxyeicosatetraenoic acids (EEQs), particularly 17,18-EEQ; osmotic pump delivery of 17,18-EEQ mimicked the protective effects of exercise, reducing infarct burden and enhancing proliferation markers (Ki67, pH3, Aurora B). Transcriptomic analysis identified NR4A1 as the most prominent up-regulated mRNA under exercise induction; AAV9-mediated NR4A1 knockdown abolished exercise-mediated cardioprotection and proliferative benefits, establishing NR4A1 as essential for exercise-driven repair. Phosphoproteomic profiling revealed that 17,18-EEQ activates the PKA-CREB pathway to induce NR4A1 expression; pharmacological inhibition of adenylyl cyclase, PKA, or CREB phosphorylation reversed EEQ-mediated cardioprotection and proliferation, confirming pathway necessity. Dietary supplementation with eicosapentaenoic acid (EPA), the metabolic precursor of 17,18-EEQ, amplified exercise-induced cardioprotection by enhancing EEQ biosynthesis. CONCLUSIONOur study identifies 17,18-EEQ as an exercise-derived exerkine that promotes cardiomyocyte proliferation and post-MI repair through a PKA-CREB-NR4A1 signaling axis, advancing our understanding of exercise cardioprotection and myocardial regeneration mechanisms while providing novel therapeutic targets for cardiac intervention. What IS New?O_LIAerobic exercise enhances post-myocardial infarction cardiac repair by upregulating the cardio-protective lipid mediator 17,18-EEQ and its downstream effector NR4A1. C_LIO_LI17,18-EEQ promotes cardiomyocyte proliferation and cardiac repair through activation of the cAMP-PKA-NR4A1 signaling axis. C_LIO_LICombining aerobic exercise with omega-3 fatty acid supplementation synergistically improves cardiac remodeling and functional recovery after ischemic injury. C_LI What Are the Clinical Implications?O_LITargeting endogenous cardiomyocyte proliferation represents a promising therapeutic strategy for cardiac regeneration after ischemic injury. C_LIO_LIDietary supplementation with omega-3 fatty acids may be a clinically feasible approach to amplify exercise-induced cardioprotection and improve outcomes after myocardial infarction. C_LI