AIM:To investigate the mechanism by which N6-methyladenosine(m6A)methylase methyltrans-ferase-like protein 3(METTL3)regulates the differentiation of human bone marrow mesenchymal stem cells(MSCs)into adipocytes in vitro.METHODS:Lentiviral vectors of METTL3,AKT serine/threonine kinase 1(AKT1),peroxisome pro-liferator-activated receptor γ(PPARγ)and YTH m6A RNA binding protein F2(YTHDF2)were constructed to package lentiviral particles and used to infect MSCs.A human bone MSC adipogenic differentiation kit was used to induce the MSCs into adipocytes.Additionally,the adipocytes were stained by oil red O.The recombinant vector of METTL3 mutant was constructed using molecular cloning to confirm the regulatory effect of the key site of m6A in METTL3 on the target genes.Actinomycin D was applied to MSCs with overexpression of YTHDF2 to evaluate the effect of YTHDF2 recognition on the mRNA and protein expression of AKT1.The RNA pull-down assay combined with silver staining and Western blot were used to detect the binding of potentially methylated fragments to recognized proteins.RESULTS:METTL3 inhibited the adipogenesis of MSCs in an AKT1/PPARγ-dependent manner,and mediated the protein expression of AKT1 in an m6A-YTHDF2-dependent manner.YTHDF2 recognized and bound to coding sequence(CDS)of m6A-AKT1,and reduced its expression,which inhibited the adipogenesis of MSCs.CONCLUSION:The m6A methylase METTL3 regulates the adipo-genic differentiation of human bone marrow MSCs through YTHDF2/AKT1/PPARγ,providing a theoretical basis for the identification of new targets for acute myeloid leukemia treatment from the perspective of tumor microenvironment.