METTL1 and Disorder of lipid metabolism: Furthermore, overexpression of METTL1 in MSCs exacerbated lipid metabolic disorders in MASLD mice by inhibiting the NAMPT/SIRT1/SREBP1 signaling pathway.<h4>Conclusion</h4>METTL1-deficient MSCs alleviate MASLD-associated lipid metabolic disorders via NAMPT secretion.