Dapagliflozin Prevents NOX- and SGLT2-Dependent Oxidative Stress in Lens Cells Exposed to Fructose-Induced Diabetes Mellitus

Abstract

Purpose: Cataracts in patients with diabetes mellitus (DM) are a major cause of blindness in developed and developing countries. This study aims to examine whether the generation of reactive oxygen species (ROS) via the increased expression of glucose transporters (GLUTs) and the receptor for advanced glycation end products (RAGE) influences the cataract development in DM. Methods: Lens epithelial cells (LECs) were isolated during cataract surgery from patients without DM or with DM, but without diabetic retinopathy. In a rat model, fructose (10% fructose, 8 or 12 weeks) with or without dapagliflozin (1.2 mg/day, 2 weeks) treatment did induce DM, as verified by blood pressure and serum parameter measurements. Immunofluorescence stainings and immunoblottings were used to quantify the protein levels. Endogenous O2˙¯ production in the LECs was determined in vivo with dihydroethidium stainings. Results: We investigated that GLUT levels in LECs differed significantly, thus leading to the direct enhancement of RAGE-associated superoxide generation in DM patients with cataracts. Superoxide production was significantly higher in LECs from rats with fructose-induced type 2 DM, whereas treatment with the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin prevented this effect in fructose-fed rats. Protein expression levels of the sodium/glucose cotransporter 2 (SGLT2), GLUT1, GLUT5, the nicotinamide adenine dinucleotide phosphate reduced form (NADPH) oxidase subunit p67-phox, NOX2/4 and RAGE were upregulated in fructose-fed animals, whereas dapagliflozin treatment reversed these effects. Conclusions: In rats with fructose-induced DM, dapagliflozin downregulates RAGE-induced NADPH oxidase expression in LECs via the inactivation of GLUTs and a reduction in ROS generation. These novel findings suggest that the SGLT2 inhibitor dapagliflozin may be a candidate for the pharmacological prevention of cataracts in patients with DM.

MicroRNA-182-5p protects human lens epithelial cells against oxidative stress-induced apoptosis by inhibiting NOX4 and p38 MAPK signalling

“…NOX4derived ROS play an important role in p38 MAPK signalling [27] and regulation of mitochondrial function [28]. A recent study reports that dapagliflozin decreases NOX4 levels in the LECs from fructose-fed rats, thereby reducing ROS generation during fructoseinduced diabetic cataracts [29]. We confirmed that miR-182-5p inhibited H 2 O 2 -stimulated apoptosis of HLE-B3 cells; however, this effect was reversed by overexpression of NOX4.…”

AKR1B1-Induced Epithelial–Mesenchymal Transition Mediated by RAGE-Oxidative Stress in Diabetic Cataract Lens

“…Interestingly, AKR1B1 and RAGE levels were only significantly elevated in the LECs of DM (+) patients in the present study ( Figure 2). Our previous work similarly demonstrated that sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors enabled glycemic control in type 2 diabetes mellitus (T2DM) patients, by downregulating RAGE-induced NADPH oxidase expression in LECs via the inactivation of GLUTs and reduced ROS generation [9]. Wang S. et al reported that AMPKα2 deletion enhanced NADPH oxidase subunit expression and increased oxidative stress in vascular endothelial cells [36].…”

“…Superoxide dismutase (SOD) is a predominant antioxidant enzyme in the lens that degrades superoxide radicals (O 2− ) into H 2 O 2 and oxygen. SOD also protects the lens against cataract development in DM models [8,9]. As a consequence, decreased activity of antioxidant enzymes and reducing substances, excessive AR activation, and AGE accumulation are risk factors for DC occurrence [10,11].…”

No Cytotoxic and Inflammatory Effects of Empagliflozin and Dapagliflozin on Primary Renal Proximal Tubular Epithelial Cells under Diabetic Conditions In Vitro

“…Several in vitro studies using immortalized human tubular epithelial cells (e.g., HK2 cell line) [25][26][27][28], murine tubular epithelial cells [29] or non-renal cells [30,31] investigated either the effects of empa-or of dapagliflozin. Some of them have shown that SGLT2 inhibition reduced the release of inflammatory or fibrotic factors induced by high glucose levels [25][26][27], others found effects on oxidative stress responses [26,30,31]. Our current study looked at whether high glucose induced changes were influenced by either of the two gliflozins.…”

“…Whereas we found no effect on cell viability, proliferation, and cytotoxicity, a significant reduction in the oxidative stress was found after incubation with dapagliflozin. Chen and co-workers also demonstrated decreased reactive oxidative species after incubation with dapagliflozin in a fructose-induced diabetic milieu [31]. Others investigated the subcellular mechanisms underlying the protective effects of empagliflozin from high glucose-mediated injuries on HK-2 cells [26].…”