Sodium-glucose cotransporter-2 inhibition reduces cellular senescence in the diabetic kidney by promoting ketone body-induced NRF2 activation.

ABSTRACT

AIMS: To evaluate whether sodium-glucose cotransporter-2 (SGLT2) inhibition reduces cellular senescence in the kidney and to investigate the molecular pathways involved in the renoprotective effect. MATERIALS AND METHODS: Dapagliflozin (1 mg/kg), glimepiride (2.5 mg/kg) or vehicle was administered daily via oral gavage for 8 weeks in db/db mice. Expression levels of ageing marker genes (p21, p16, and p53) and oxidative stress were measured in the kidney using real-time RT-PCR, immunohistochemistry, and Western blot analysis. For in vitro analysis, HK-2 cells, a human renal tubular epithelial cell line, were pretreated with H2 O2 to induce cellular senescence, and the levels of ageing markers were measured after treatment with ß-hydroxybutyrate (ß-HB) or NRF2-specific siRNA. RESULTS: Expression levels of ageing marker genes (p21, p16 and p53) and senescence-associated secretory phenotypes of the kidney were increased in the vehicle-treated db/db (db/db + vehicle) group compared with the db/+ group, and this increase was markedly reversed in the dapagliflozin-treated db/db (db/db + SGLT2 inhibitor) group, but not in the glimepiride-treated db/db (db/db + sulphonylurea [SU]) group. In the kidneys of mice in the db/db + SGLT2 inhibitor group, oxidative stress and DNA damage were also reduced compared with those of mice in the db/db + vehicle and db/db + SU groups. Dapagliflozin increased plasma ß-HB, which reduced H2 O2 -induced DNA damage and senescence in HK-2 cells. ß-HB-induced NRF2 nuclear translocation mediated anti-senescent effects by inducing antioxidant pathways. CONCLUSIONS: Dapagliflozin prevented the progression of diabetic kidney disease by inhibiting cellular senescence and oxidative stress via ketone-induced NRF2 activation.