To further explore the mechanism by which CNPY2 regulates renal tubular injury in DN, db/db mice were injected with CNPY2‐overexpressing AAV (db/db+CNPY2 OE) through the tail vein.Immunofluorescence staining showed that CNPY2 was significantly increased in RTECs of db/db mice overexpressing CNPY2 (FigureS2A). This evidence concerns the gene CNPY2 and liver dysplastic nodule.