Retinoid X receptor Agonists Inhibit High-Glucose-Induced Oxidative Stress in Human Endothelial Cells

Background Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase plays a key role in high-glucose-induced oxidative stress in human endothelial cells,retinoid X receptor (RXR) agonists can decrease high-glucose-induced reactive oxygen species(ROS) production.However,the effects of RXR ligands on individual subunit of NADPH oxidase had not been well delineated.Objective To investigate the role of NOX4,gp91phox and p22phox subunits of NADPH oxidase in high-glucose-induced oxidative stress in human endothelial cells and whether RXR agonists was able to attenuate the production of ROS mediating inhibited expression of subunits of NADPH oxidase in vitro.Methods Human umbilical vein endothelial cells (HUVECs) were isolated from healthy umbilical cords and cultured.Antisense transfection was obtained to reveal the role of subunits of NADPH oxidase in high-glucose-induced oxidative stress.Reverse transcription and real-time PCR and immunoblotting were performed to determine the expression of the subunits of NADPH oxidase and NOX4.ROS production was detected using flow cytometry.Results ROS level was significantly increased in high-glucose-induced HUVECs (6.58±0.24 vs 2.47±0.12,P0.05).High-glucose-induced ROS production in HUVECs was mainly mediated through its activation of the NOX4,gp91phox and p22phox subunits of NADPH oxidase.The mRNA levels of NOX4,gp91phox,and p22phox subunits of NADPH oxidase were significantly up-regulated by high glucose (NOX4:0.390±0.020 vs 0.110±0.006,P0.05;gp91phox:0.480±0.040 vs 0.090±0.005,P0.05;p22phox:0.025±0.002 vs 0.005±0.001,P0.05).High glucose has similar effect on protein level of these subunits.Treatment of endothelial cells with RXR agonists 9-cis-RA and SR11237 resulted in significant inhibition of ROS production and attenuate the expressionof NOX4,gp91phox,and p22phox induced by high glucose levels.Conclusion RXR agonists inhibit high-glucose-induced ROS production by repressing the expression of NADPH oxidase in human endothelial cells.