Hypoxanthine-xanthine oxidase down-regulates GLUT1 transcription via SIRT1 resulting in decreased glucose uptake in human placenta

Abstract

Appropriate foetal growth and development is dependent on adequate placental glucose uptake. Oxidative stress regulates glucose uptake in various tissues. The effect of oxidative stress on placental glucose transport is not known. Thus, the aim of this study was to determine the effect of oxidative stress on glucose uptake and glucose transporters (GLUTs) in human placenta. Human placenta was incubated in the absence or presence of 0.5 mM hypoxanthine+15 mU/ml xanthine oxidase (HX/XO) for 24 h. Gene and protein expressions of the GLUTs were analysed by quantitative RT-PCR and western blotting respectively. Glucose uptake was measured using radiolabelled ((14)C) glucose. HX/XO significantly decreased GLUT1 gene and protein expression and resultant glucose uptake. There was no effect of the antioxidants N-acetylcysteine, catalase and superoxide dismutase or the NF-κB inhibitor BAY 11-0782 on HX/XO-induced decrease in glucose uptake. However, HX/XO treatment significantly decreased both gene and protein expression of SIRT1. In the presence of the SIRT1 activator resveratrol, the decrease in GLUT1 expression and glucose uptake mediated by HX/XO was abolished. Collectively, the data presented here demonstrate that oxidative stress reduces placental glucose uptake and GLUT1 expression by a SIRT1-dependent mechanism.