NAT10 Mediates Cardiac Fibrosis Induced by Myocardial Infarction Through ac4C Modification of TGFBR1 mRNA

Cardiac fibrosis is a critical pathological process following myocardial infarction (MI), contributing to adverse cardiac remodeling and dysfunction. This study investigates the role of N-acetyltransferase 10 (NAT10), an RNA acetyltransferase, in mediating cardiac fibrosis through the N4-acetylcytidine (ac4C) modification of transforming growth factor beta receptor type 1 (TGFBR1) mRNA. Using a mouse model of MI, we demonstrated elevated levels of NAT10 and total ac4C RNA in left ventricular tissues, correlating with increased cardiac fibrosis. Echocardiographic analysis revealed significant impairment in cardiac contractile function, which was further validated by histological assessments using H&E and Masson staining. In vitro studies showed that TGF-β stimulation of cardiac fibroblasts led to enhanced NAT10 expression and myofibroblast differentiation, as evidenced by α-SMA staining. The role of NAT10 was further elucidated through fibroblast-specific knockout experiments, where the absence of NAT10 markedly attenuated cardiac fibrosis and improved echocardiographic parameters at eight weeks post-MI. Additionally, NAT10 knockout resulted in decreased mRNA and protein levels of fibrotic markers such as Collagen I and III, alongside reduced ac4C RNA modification. Additionally, we established that NAT10 enhances the stability of TGFBR1 mRNA via ac4C modification, as supported by RNA immunoprecipitation and luciferase assays. TGFBR1 overexpression countered the effects of NAT10 knockout, restoring fibrotic responses in both in vivo and in vitro models. These findings suggest that NAT10 plays a pivotal role in cardiac fibrosis following MI by regulating TGFBR1 mRNA stability through ac4C modification, thereby presenting potential therapeutic targets for mitigating cardiac fibrosis in post-MI patients.