Further mechanic study found that METTL3-mediated m6A modification on pri-miR-221 promoted its processing and maturation that subsequently upregulated miR-221-3p expression to inhibit GRB2-associated binding protein 1 (Gab1) expression, which worsened the cognitive deficits in MDD rats [42] (Figure 2). Here, METTL3 is linked to major depressive disorder.