Dapagliflozin Restores Impaired Autophagy and Suppresses Inflammation in High Glucose-Treated HK-2 Cells.

Jing Xu,Haijie Liu,Munehiro Kitada,Yoshio Ogura,Daisuke Koya

doi:10.3390/cells10061457

Abstract

Sodium-glucose cotransporter2 (SGLT2) inhibitors have a reno-protective effect in diabetic kidney disease. However, the detailed mechanism remains unclear. In this study, human proximal tubular cells (HK-2) were cultured in 5 mM glucose and 25 mM mannitol (control), 30 mM glucose (high glucose: HG), or HG and SGLT2 inhibitor, dapagliflozin-containing medium for 48 h. The autophagic flux was decreased, accompanied by the increased phosphorylation of S6 kinase ribosomal protein (p-S6RP) and the reduced phosphorylation of AMP-activated kinase (p-AMPK) expression in a HG condition. Compared to those of the control, dapagliflozin and SGLT2 knockdown ameliorated the HG-induced alterations of p-S6RP, p-AMPK, and autophagic flux. In addition, HG increased the nuclear translocation of nuclear factor-κB p65 (NF-κB) p65 and the cytoplasmic nucleotide-binding oligomerization domain-like receptor 3 (NLRP3), mature interleukin-1β (IL-1β), IL-6, and tumor necrosis factorα (TNFα) expression. Dapagliflozin, SGLT2 knockdown, and NF-κB p65 knockdown reduced the extent of these HG-induced inflammatory alterations. The inhibitory effect of dapagliflozin on the increase in the HG-induced nuclear translocation of NF-κB p65 was abrogated by knocking down AMPK. These data indicated that in diabetic renal proximal tubular cells, dapagliflozin ameliorates: (1) HG-induced autophagic flux reduction, via increased AMPK activity and mTOR suppression; and (2) inflammatory alterations due to NF-κB pathway suppression.

Highlights

Diabetic kidney disease (DKD) is one of the main chronic complications of diabetes and the leading cause of end-stage renal disease (ESRD) [1]
70–80% confluent, the cells were cultured with high glucose stimulation in 30 mM glucosecontaining medium (HG) for 48 h, while cells cultured in 5 mM glucose-containing medium supplemented with 25 mM mannitol were used as controls (Cont)
HG induced the expression of Sodium-glucose cotransporter 2 (SGLT2), and both dapagliflozin and SGLT2 knockdown ficiency significantly suppressed

Summary

Introduction

Diabetic kidney disease (DKD) is one of the main chronic complications of diabetes and the leading cause of end-stage renal disease (ESRD) [1]. Despite various therapeutic options for glucose control, many diabetic patients remain at high risk for development and progression of DKD. There is an urgent need for more effective interventions for preventing the development and progression of DKD. SGLT2 inhibitors are effective antidiabetic drugs that attenuate hyperglycemia by suppressing renal glucose reabsorption. The results of large-scale clinical studies have shown that SGLT2 inhibitors improve hyperglycemia independently of insulin [3,4] and present renoprotective and cardioprotective effects in diabetic patients [5,6,7]. Dapagliflozin treatment has led to remarkable renal outcomes [5,8], the relevant mechanisms have still not been fully elucidated

Methods

Results

Conclusion