Abstract / Summary
ABSTRACT Dapagliflozin, a potent sodium‐glucose cotransporter 2 (SGLT2) inhibitor, slows diabetic kidney disease (DKD) progression and reduces blood pressure in diabetic mice, potentially via modulation of tubular sodium transporters and inflammatory pathways. RING‐type E3 ligases, including cullin‐based complexes, regulate the stability of with‐no‐lysine kinases (WNK1/4), key upstream activators of the sodium‐potassium‐chloride cotransporter 2 (NKCC2). Twelve‐week‐old male db/db mice were placed on a high‐salt diet to induce hypertension and accelerate DKD, then randomized to receive dapagliflozin or vehicle by oral gavage for 14 days. Metabolic cages were used for 24‐h urine collection, and glomerular filtration rate was measured using FITC‐sinistrin clearance. Blood pressure was assessed by tail‐cuff plethysmography. Kidneys were processed for histology, immunohistochemistry, Western blotting, and label‐free proteomics. Dapagliflozin markedly reduced systolic blood pressure and improved renal injury on Periodic acid–Schiff staining, accompanied by reduced lactic acid accumulation and a lower urinary albumin‐to‐creatinine ratio. Proteomic profiling demonstrated differential abundance of multiple signaling proteins between groups. Western blotting showed increased expression of cullin 1, 2, and 3 family members, with a significant reduction in NKCC2 and aquaporin‐2 protein levels in dapagliflozin‐treated mice. In cultured mouse thick ascending limb cells, dapagliflozin inhibited high glucose–induced activation of the NLRP3 inflammasome, indicating an additional anti‐inflammatory effect. Dapagliflozin confers renoprotection in salt‐loaded hypertensive db/db mice by lowering blood pressure, attenuating tubular and glomerular injury, reducing NKCC2 abundance possibly via enhanced cullin‐mediated degradation, and attenuating high‐glucose–induced NLRP3 protein expression.