At present, it is known that a variety of pathways play an important role in the occurrence and development of DN, such as TGF-β (Sharma and McGowan, 2000), Notch (Lin et al., 2010), Wnt (Rooney et al., 2011) pathway, and FGFR1, SIRT3, and dipeptidyl peptidase-4 (DPP-4) mediated signaling mechanisms also play an important role in the occurrence and development of DN (Liu Y. et al., 2022). Here, DPP4 is linked to liver dysplastic nodule.