Resveratrol suppresses hyperglycemia-induced activation of NF-κB and AP-1 via c-Jun and RelA gene regulation.

Background: Resveratrol (RSV) provides several important biological functions in wide variety of cells. In this study, we investigated the molecular mechanisms underlying anti-inflammatory effect of RSV on HepG2 cells by assessing the gene expression of RelA and c-Jun- subunits of NF-κB and AP-1 transcription factors. Methods: HepG2 cells were settled in a serum- free medium with high concentrations of glucose (30 mM) and insulin (1 µM) overnight and were then incubated with RSV (5, 10, and 20 µM) for 24 and 48 hours. Real time quantitative polymerase chain reaction (qRT-PCR) was used to determine RelA and c-Jun expression. Results: RSV diminished hyperglycemia/hyperinsulinemia stimulated expression of c-Jun dose- dependently after 24 and 48 hours (p<0.05). In addition, RelA gene expression was decreased dose-dependently in all RSV doses after 48-hour incubation (p<0.05). Our results indicated that RSV may reduce NF-κB and AP-1 activity via RelA and c-Jun gene regulation. Conclusion: The findings of the present study demonstrated that RSV may be considered as a preventative and therapeutic agent for antagonizing inflammation in Hepatocellular carcinoma (HCC).

Does Resveratrol Improve Insulin Signalling in HepG2 Cells?

OBJECTIVES: Diabetes mellitus is a common metabolic disorder with high global prevalence. It is characterized by a decrease in insulin secretion or a decrease in insulin sensitivity or both. The aim of the present study was to investigate the effects of resveratrol treatment on the expression of the genes involved in insulin signalling cascade, such as Forkhead box protein O1 (FoxO1), 3-phosphoinositide-dependent protein kinase 1 (PDPK1) and mammalian target of rapamycin (mTOR). METHODS: HepG2 cells were cultured in serum-free medium with high concentrations of glucose and insulin and then were treated with resveratrol (5, 10 and 20 µM) for 24 and 48 hours. Complementary deoxyribonucleic acids (cDNAs) were synthesized followed by RNA extraction. Real-time quantitative reverse transcription polymerase chain reaction was used to analyze the expression of FoxO1, PDPK1 and mTOR. RESULTS: Resveratrol increased the expression of PDPK1, mTOR and FoxO1. No significant difference was seen among differing dosages of resveratrol, but treatments for 48 hours exerted the greatest effectiveness. CONCLUSIONS: Our results were consistent with other studies showing the beneficial effects of resveratrol on diabetes. However, considering the effects of resveratrol in increasing FoxO1 and gluconeogenic gene expression, long-term usage of resveratrol should be investigated in greater depth in future studies.