Dapagliflozin improves diabetic kidney disease by inhibiting ferroptosis through β-hydroxybutyrate production.

Background: Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Sodium-glucose cotransporter protein 2 inhibitors (SGLT2i) are antihyperglycemic agents that provide additional renal-protective effects in patients with DKD, independent of their glucose-lowering effects. However, the underlying mechanism remains unclear. This study hypothesized that SGLT2i could alleviate diabetic kidney injury by inhibiting ferroptosis and explored its potential mechanisms.

Methods: C57BL/6J mice were randomly divided into the control, DKD, DKD+dapagliflozin, and DKD+insulin treatment groups. Blood glucose levels and body weight were monitored. Renal function, tissue pathology, mitochondrial morphology and function, and lipid peroxidation biomarkers (lipid peroxidation [LPO], malondialdehyde [MDA], glutathione peroxidase 4 [GPX4], glutathione [GSH], and cystine transporter solute carrier family 7 member 11 [SLC7A11]) were evaluated. Human proximal tubule cells (HK2 cells) were exposed to high glucose alone or in combination with dapagliflozin. The mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) level, NAD+/NADH ratio (oxidized/reduced ratio of nicotinamide adenine dinucleotide), and lipid peroxidation were measured. In addition, the role of the β-hydroxybutyrate- Calcium/Calmodulin Dependent Protein Kinase Kinase 2 (BHB-CaMKK2) axis in mediating dapagliflozin regulating ferroptosis was examined.

Results: Dapagliflozin significantly ameliorated kidney injury in mice with DKD. Typical changes in ferroptosis, including lipid peroxidation and impaired antioxidant capacity, increased in mice with DKD and HG-treated HK-2 cells. Dapagliflozin significantly improves ferroptosis-related lipid peroxidation and mitochondrial dysfunction. Furthermore, dapagliflozin suppressed the expression of CaMKK2, a key ferroptosis regulator. Specific CaMKK2 inhibitors alleviated mitochondrial damage and ferroptosis, whereas a CaMKK2 agonist counteracted the protective effects of dapagliflozin against mitochondrial, antioxidant, and anti-ferroptosis effects. In addition, dapagliflozin increased BHB production, which mediates its nephroprotective effects.

Conclusion: Dapagliflozin improves DKD by inhibiting ferroptosis, promoting BHB production, and regulating CaMKK2.