Geniposide ameliorates diabetic nephropathy in type 2 diabetic mice by targeting AGEs-RAGE-dependent inflammatory pathway.

BACKGROUND

Diabetic nephropathy (DN) is a prevalent complication of diabetes mellitus and the primary cause of morbidity and mortality in end-stage renal disease. The receptor for advanced glycation end products (RAGE) plays a crucial role in mediating AGE-triggered inflammation, which has been implicated in DN pathogenesis. While geniposide, a natural compound, has demonstrated anti-inflammatory and hypoglycemic properties, its potential to mitigate AGE-induced renal inflammation and consequently impede DN progression remains unexplored.

PURPOSE

The objective of this study was to ascertain whether geniposide is a novel natural AGEs-RAGE blocker and to investigate its protective effect on renal DN in type 2 diabetic mice.

METHODS

Binding affinity between geniposide and RAGE was assessed using MicroScale Thermophoresis (MST), molecular docking, and co-immunoprecipitation. RAGE was then subjected to knockdown and overexpression in cellular experiments to evaluate geniposide's effects on AGE-induced inflammatory responses and the RAGE pathway. Finally, db/db mice were employed to validate the renoprotective effects of geniposide in DN.

RESULTS

Geniposide exhibited higher binding affinity to RAGE's V domain than AGEs, competitively inhibiting AGEs-RAGE interaction through hydrogen bonding. It suppressed RAGE expression and RAGE-dependent inflammatory responses to AGEs, comparable to RAGE siRNA effects. In RAGE-overexpressing cells, geniposide further inhibited AGEs-induced ERK1/2 and NFκB P65 activation, reducing inflammatory marker levels. Long-term oral administration of geniposide to db/db mice improved plasma creatinine, urea, and proteinuria levels, ameliorated pathological changes, and downregulated inflammatory factors such as TNF-α and IL-1β. Moreover, it dose-dependently attenuated enhanced renal expression of RAGE, phosphorylated ERK1/2, IκB-α, and NF-κB P65.

CONCLUSION

Geniposide effectively attenuates AGEs-induced RAGE activation by directly blocking AGEs-RAGE signal transduction, thereby mitigating inflammatory responses. These findings suggest that geniposide has potential as a high-affinity RAGE antagonist, potentially playing a crucial role in the treatment of DN.