GLP-1/GIP dual agonist tirzepatide normalizes diabetic nephropathy via PI3K/AKT mediated suppression of oxidative stress

Background: Effective therapeutic approaches for the treatment of diabetic nephropathy (DN) with irreversible deterioration of renal function are currently lacking. In this study, we aimed to investigate the ability of the glucagon-likepeptide-1 (GLP-1)/ gastric inhibitory polypeptide (GIP) dual agonist, tirzepatide to alleviate DN in mice and its underlying mechanisms. Methods: We investigated the reno-protective effect of semaglutide and tirzepatide in a mouse model of DN, an insulin-treated positive control group was also included. Indicators of diabetic kidney injury and oxidative stress biomarkers were also assessed. RNA-seq analysis of renal tissue was conducted to explore the potential mechanism of action of tirzepatide and in vitro cell experiments were performed to validate its pathway. Results: In DN mice, one-third the dose of tirzepatide was consistent with that of semaglutide in lowering glucose, body weight, and urine albumin-to-creatine ratio (UACR) and in improving antioxidative stress activities, while insulin treatment could not effectively restore the UACR. RNA-seq analysis revealed that the PI3K-AKT signaling pathway was significantly enriched after tirzepatide treatment compared with that in the DN model. Confirmatory experiments demonstrated that tirzepatide regulated oxidative stress and the PI3K-AKT pathway in mouse podocyte cell-5 cells exposed to high glucose. Further mechanistic validation suggested that the anti- oxidative activity of tirzepatide was reversed by PI3K inhibitor. Conclusion: These findings expand the potential effects and mechanics of tirzepatide in the treatment of DN, which may provide a novel therapeutic approach and therapeutic target for DN treatment.