FTO suppresses cardiac fibrosis after myocardial infarction via m 6 A-mediated epigenetic modification of EPRS

Abstract Background Cardiac fibrosis is common in cardiovascular diseases. Previous research has suggested that m⁶A modification is vital in cardiovascular diseases. However, the effects of m⁶A demethylase fat mass and obesity protein (FTO) on cardiac fibrosis have not been detected. Methods Western blot and Quantitative real-time PCR were performed to detect the expression of FTO in the fibrotic tissue of rats and hypoxia-induced cardiac fibroblasts (CFs). The HIF-1 signal pathway was enriched, and a CUT&Tag assay was performed to explore the effects on FTO. The biological functions of FTO were analyzed in vitro and in vivo. The underlying targets of FTO were selected through RNA-seq with m⁶A-seq. The following dual luciferase reporter assay and RNA stability assay were conducted to investigate the mechanisms of FTO-mediated m⁶A regulation. Results The expression of FTO was decreased in the fibrotic tissue of rats and hypoxia-induced CFs. The knockdown of HIF-1α, instead of HIF-2α, increased the mRNA level of FTO. HIF-1α could bind to the promoter of FTO and inhibit FTO expression. FTO inhibited collagen synthesis in CFs. According to m⁶A-seq and RNA-seq, EPRS was selected as the underlying target of FTO-induced m⁶A regulation. IGF2BP3 recognized and bound to the m⁶A sites of EPRS mRNA, which improved its stability. EPRS was required for cardiac fibrosis induced by FTO silencing. Conclusions HIF-1α induced by MI bound to the FTO promoter and inhibited FTO expression. FTO suppressed collagen synthesis of CFs in cardiac fibrosis via m⁶A-mediated modification, which provided a new therapeutic strategy for cardiac fibrosis.