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Phosphorylation of NCC and its Association with The Actin Cytoskeleton Linker Protein Ezrin in the Diabetic Kidney is Reduced by Dapagliflozin Treatment
Author(s) -
Gholam Mohammed,
Alli Abdel
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.03195
Subject(s) - ezrin , reabsorption , kidney , dapagliflozin , chemistry , distal convoluted tubule , endocrinology , medicine , actin cytoskeleton , western blot , cytoskeleton , diabetes mellitus , type 2 diabetes , biochemistry , cell , gene
Ezrin, an actin cytoskeleton linker protein is known to regulate various membrane proteins in the kidney. The Sodium Chloride Cotransporter (NCC) is responsible for 5‐10% of salt reabsorption from the filtrate in the distal convoluted tubules. Dapagliflozin, an SGLT2 inhibitor, is a novel drug in the treatment of type 2 diabetes mellitus. We hypothesize that dapagliflozin decreases sodium reabsorption and blood pressure by attenuating the association between NCC and ezrin in the distal convoluted tubules in the hypertensive diabetic db/db mice. Twelve week‐old male db/db mice with a blood glucose of more than 300 mg/dl were salt‐loaded (4% NaCl) for 10 days to induce hypertension. The mice were subjected to metabolic cage studies for 24‐hour urine collections in order to measure urinary electrolytes, creatinine, and albumin. Blood pressure was measured by the tail‐cuff method to evaluate the effect of dapagliflozin or vehicle given by oral gavage (10 mg/kg of body weight per day for 2 weeks). At the end of the study the mice were euthanized, and the left kidney was formalin‐fixed and paraffin‐embedded for 3,3′‐Diaminobenzidine (DAB) double staining for phospho‐NCC and ezrin proteins while the right kidney was homogenized for Western blotting. Western blot analysis showed attenuation of total NCC and ezrin proteins in the diabetic db/db mice given an oral gavage of dapagliflozin compared to vehicle. DAB analysis showed reduced expression of the actin cytoskeleton linker protein ezrin and phosphorylated NCC in the dapagliflozin treated group compared to the control group. Taken together, we show dapagliflozin decreases sodium retention and blood pressure by reducing the density of renal NCC at the luminal membrane and the association between NCC and the actin cytoskeleton.