In this study, we made the following observations: 1) METTL14 catalyzed the m6A modification of pri-miR-34a to promote the binding of pri-miR-34a to DGCR8, which, in turn, increased the expression of mature miR-34a-5p; 2) miR-34a-5p bound to SIDT2 mRNA, suppressing SIDT2 expression; and 3) inhibition of SIDT2 promoted the expression of mitochondrial fission proteins Fis1 and Drp1 and inhibited the expression of mitochondrial fusion protein Mfn2, leading to imbalance of mitochondrial homeostasis and aggravation of NAFLD (Figure 8). The gene discussed is MFN2; the disease is metabolic dysfunction-associated steatotic liver disease.