1-Deoxynojirimycin Attenuates High-Glucose-Induced Oxidative DNA Damage via Activating NRF2/OGG1 Signaling

Abstract

1-Deoxynojirimycin (DNJ) is a type of alkaloid that mainly exists in mulberry fruit and leaves. DNJ inhibits α-glucosidase, reduces the absorption of sugar, and suppresses after-meal hyperglycemia. It was reported that DNJ functions in attenuating cellular oxidative stress. However, the mechanisms remain largely unknown. In this study, we firstly confirmed that 5 µmol/L DNJ treatment mitigated the oxidative DNA damage and cell senescence in human umbilical vein endothelial cells (HUVEC) cultured in medium containing 50 mmol/L glucose. Next, we found that DNJ treatment stimulates the expression of anti-oxidative response regulator, Nuclear factor (erythroid-derived 2)-like 2 (NRF2) by around 50% in cells cultured with high glucose. In addition, 8-oxoguanine DNA glycosylase (OGG1) was upregulated by over 15% after DNJ treatment to mitigate high-glucose-induced oxidative DNA damage, and it was identified as a downstream target of NRF2. Further, DNJ treatment promoted the phosphorylation and activation of AKT (ser473) by around 50% in cells cultured with high glucose, and AKT inhibitor treatment abrogated DNJ-induced upregulation of NRF2 and OGG1. Taken together, our results indicate that DNJ is an effective natural antioxidant in mitigating high-glucose-induced oxidative stress in HUVEC via activating the AKT-NRF2-OGG1 anti-oxidative response.