N6-methyladenosine (m⁶A) mRNA modification plays critical roles in various biological events and is involved in multiple complex diseases. However, the role of m⁶A modification in autophagy in nonalcoholic fatty liver disease (NAFLD) remains largely unknown. Here, we report that m⁶A modification was increased in livers of NAFLD mouse models and in free fatty acid (FFA)-treated hepatocytes, and the abnormal m⁶A modification was attributed to the upregulation of methyltransferase like 3 (METTL3) induced by lipotoxicity. Knockdown of METTL3 promoted hepatic autophagic flux and clearance of lipid droplets (LDs), while overexpression of METTL3 inhibited these processes. Mechanistically, METTL3 directly bound to Rubicon mRNA and mediated the m⁶A modification, while YTH N6-methyladenosine RNA binding protein 1 (YTHDF1), as a partner of METTL3, interacted with the m⁶A-marked Rubicon mRNA and promoted its stability. Subsequently, RUBICON inhibited autophagosome-lysosome fusion and further blocked clearance of LDs. Taken together, our results showed a critical role of METTL3 and YTHDF1 in regulating lipid metabolism via the autophagy pathway and provided a novel insight into m⁶A mRNA methylation in NAFLD.

N 6-甲基腺苷 (m ⁶ A) mRNA 修饰在各种生物事件中起着关键作用，并参与多种复杂疾病。然而，m ⁶ A 修饰在非酒精性脂肪性肝病 (NAFLD) 自噬中的作用在很大程度上仍然未知。在这里，我们报告了 m ⁶ A 修饰在 NAFLD 小鼠模型的肝脏和游离脂肪酸 (FFA) 处理的肝细胞中增加，异常的 m ⁶ A 修饰归因于甲基转移酶样 3 (METTL3) 的上调脂毒性。METTL3 的敲低促进了肝脏自噬通量和脂滴 (LD) 的清除，而 METTL3 的过表达抑制了这些过程。从机制上讲，METTL3 直接绑定到Rubicon mRNA 并介导 m ⁶ A 修饰，而 YTH N 6-甲基腺苷 RNA 结合蛋白 1 (YTHDF1) 作为 METTL3 的伙伴，与 m ⁶ A 标记的Rubicon mRNA 相互作用并促进其稳定性。随后，RUBICON 抑制自噬体-溶酶体融合并进一步阻断 LD 的清除。^{综上所述，我们的结果表明 METTL3 和 YTHDF1 在通过自噬途径调节脂质代谢中发挥关键作用，并提供了对 NAFLD 中 m 6} A mRNA 甲基化的新见解。