GPR107 and liver dysplastic nodule: This, in turn, activates the AT1R/Ca2+ signaling pathway to promote phosphorylation of cAMP-response element-binding protein (CREB), ultimately enhancing COL4 synthesis and inhibiting the expression of matrix metalloproteinase 2 (MMP-2). These findings shed light on new functions of GPR107 in DN and offer new insights into a therapeutic target for DN.