Empagliflozin Protects HK-2 Cells from High Glucose-Mediated Injuries via a Mitochondrial Mechanism.

Wen-Chin Lee,Hwee-Yeong Ng,Chia-Wei Liou,Tsu-Kung Lin,Chiu-Hua Chen,Pei-Wen Wang,Jin-Bor Chen,You-Ying Chau

doi:10.3390/cells8091085

Abstract

Empagliflozin is known to retard the progression of kidney disease in diabetic patients. However, the underlying mechanism is incompletely understood. High glucose induces oxidative stress in renal tubules, eventually leading to mitochondrial damage. Here, we investigated whether empagliflozin exhibits protective functions in renal tubules via a mitochondrial mechanism. We used human proximal tubular cell (PTC) line HK-2 and employed western blotting, terminal deoxynucleotidyl transferase dUTP nick end labelling assay, fluorescence staining, flow cytometry, and enzyme-linked immunosorbent assay to investigate the impact of high glucose and empagliflozin on cellular apoptosis, mitochondrial morphology, and functions including mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production, and adenosine triphosphate (ATP) generation. We found that PTCs were susceptible to high glucose-induced mitochondrial fragmentation, and empagliflozin ameliorated this effect via the regulation of mitochondrial fission (FIS1 and DRP1) and fusion (MFN1 and MFN2) proteins. Empagliflozin reduced the high glucose-induced cellular apoptosis and improved mitochondrial functions by restoring mitochondrial ROS production, MMP, and ATP generation. Our results suggest that empagliflozin may protect renal PTCs from high glucose-mediated injuries through a mitochondrial mechanism. This could be one of the novel mechanisms explaining the benefits demonstrated in EMPA-REG OUTCOME trial.

Highlights

Diabetic kidney disease (DKD) affects approximately 40% of patients with diabetes and has emerged as a leading cause of chronic kidney disease worldwide [1,2,3]
The viability of HK-2 cells treated with the indicated concentrations of glucose and500, empagliflozin nM under normal
Magnified images of Earlier, we have demonstrated the effect of high glucose on mitochondrial fragmentation in human proximal tubular cell (PTC) [14]

Summary

Introduction

Diabetic kidney disease (DKD) affects approximately 40% of patients with diabetes and has emerged as a leading cause of chronic kidney disease worldwide [1,2,3]. Empagliflozin, one of the sodium-glucose cotransporter 2 (SGLT2) inhibitors, has recently been reported to retard the progression of DKD in EMPA-REG OUTCOME trial [4]. Animal studies have shown that empagliflozin improves renal functions [5] and is associated with reduced hyperfiltration, albuminuria [6], and ameliorated pathology [7]. The mechanisms underlying these effects remain largely unknown. The proposed mechanisms include weight loss, natriuresis, and renal tubuloglomerular feedback [8].

Methods

Results

Conclusion