METTL3-mediated Klf9 mRNA stabilization contributes to white adipose tissue beiging

The induction of beige adipocytes in white adipose tissue (WAT), also known as WAT beiging, improves glucose and lipid metabolism. However, the regulation of WAT beiging at the posttranscriptional level remains elusive. Here, we report that METTL3, the methyltransferase of N6-methyladenosine (m6A) mRNA modification, is induced during WAT beiging in mice. Adipose-specific depletion of Mettl3 gene undermines WAT beiging. Transcriptomic analysis of m6A modifications and mRNA expression level reveals global reduction of m6A-modified mRNAs in Mettl3-depleted beige adipose tissue. In particular, METTL3-catalyzed m6A installation on Krüppel-like factor 9 (Klf9) mRNA prevents its degradation. We further demonstrate that the m6A reader protein IGF2BP3 mediates the stabilization of m6A-modified Klf9 mRNA. Overexpressioin of KLF9 protein reverses the impaired WAT beiging elicited by Mettl3 deletion. These findings uncover a novel epitranscriptional mechanism in WAT beiging and identify METTL3-KLF9 axis as a potential therapeutic target for obesity-associated disorders. Investigating the role of METTL3-mediated m6A modification in beiging