Fto-Mediated m6A Demethylation of Anxa1 Attenuates Cardiac Ischemia-Reperfusion Injury With Suppression of Nlrp3 Inflammasome Signals.

BACKGROUND

Myocardial ischemia-reperfusion (I/R) injury represents the major obstacle to achieving successful therapeutic outcomes in acute myocardial infarction patients. Fat mass and obesity-associated protein (Fto), an N6-methyladenosine (m6A) RNA demethylase, has been shown to protect cardiomyocytes against oxygen-glucose deprivation/reperfusion-mediated injury by regulating annexin A1 (Anxa1) expression in vitro. The present study aims to confirm the cardioprotective role of the Fto/Anxa1 axis using in vivo myocardial I/R injury models.

METHODS

Wild-type (WT) and Anxa1 knockout (KO) mice underwent 30-min left coronary artery ligation and 2-h reperfusion after intramyocardial delivery of recombinant adeno-associated virus serotype 9 encoding Fto (adFto) or a control vector (adnull). The effects of Fto overexpression on cardiac function, fibrosis, apoptosis, and inflammatory response were examined using echocardiography, Masson's trichrome staining, western blot analysis, enzyme-linked immunosorbent assay, and immunohistochemical staining. m6A-RNA immunoprecipitation-quantitative polymerase chain reaction quantified Anxa1 mRNA methylation.

RESULTS

Fto overexpression by adFto significantly improved cardiac function, reduced serum creatine kinase-myocardial band and troponin T levels, and alleviated cardiac fibrosis in I/R-injured WT mice. Mechanistically, Fto weakened I/R-induced global m6A levels and decreased m6A enrichment on Anxa1 mRNA, thereby enhancing Anxa1 expression. In Anxa1 KO mice, adFto did not confer functional or molecular benefit.

CONCLUSIONS

Fto enhances Anxa1 and mitigates myocardial I/R injury with suppression of nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain- containing receptor 3 (Nlrp3)-inflammasome signaling in vivo, identifying the Fto-Anxa1 axis as a mechanistic contributor and potential therapeutic target.