m6A methyltransferase WTAP regulates myocardial ischemia reperfusion injury through YTHDF1/FOXO3a signaling

N⁶-methyladenosine (m⁶A) is emerging as an essential regulator in the progression of myocardial ischemia reperfusion (I/R) injury. However, the in-depth functions and mechanisms for m⁶A are still unclear. This work aimed to explore the potential functions and mechanisms for myocardial I/R injury. In this study, m⁶A methyltransferase WTAP and m⁶A modification level elevated in the hypoxia/reoxygenation (H/R) induced rat cardiomyocytes (H9C2) and I/R injury rat model. Bio-functional cellular experiments demonstrated that knockdown of WTAP remarkably released the proliferation and reduced the apoptosis and inflammatory cytokines induced by H/R. Moreover, exercise training alleviated WTAP level in exercise-trained rats. Mechanistically, methylated RNA immunoprecipitation sequencing (MeRIP-Seq) revealed that a remarkable m⁶A modification site was found in the 3'-UTR of FOXO3a mRNA. Moreover, WTAP triggered the installation of m⁶A modification on FOXO3a mRNA through m⁶A reader YTHDF1, thereby enhancing the stability of FOXO3a mRNA. Collectively, WTAP/YTHDF1/m⁶A/FOXO3a axis regulates the myocardial I/R injury progression, which provides new insights for the treatment of myocardial injury.