Resveratrol Inhibits Hypoxia-induced Vascular Endothelial Growth Factor Expression Through Regulating Akt Phosphorylation And Hif1-α Stability In Human Retinal Pigment Epithelial Cells.

Abstract

Purpose: : Resveratrol (tans-3, 4’, 5-trihydroxystibene), a natural compound found in grapes (red wine) and other plants has anticancer activity through inhibition of angiogenesis. Vascular endothelial growth factor (VEGF), up regulated by hypoxic stimulation, plays a critical role in choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD). We investigated the effect of resveratrol on Hypoxia -inducible factor 1α (HIF-1α) and VEGF expression in human retinal pigment epithelial cells.

Methods: : Human retinal pigment epithelial cells (ARPE19) were treated with different concentration of resveratrol (10μmol/L, 50μmol/L, and 100μmol/L) and incubated in hypoxic condition (1% O₂/ 95% N₂) for 4h or 16h. Cellular cytotoxic effect of resveratrol was analyzed using MTT assay. Levels of secreted VEGF were determined by ELISA. VEGF mRNA expression was evaluated by RT-PCR under normoxia and hypoxia condition.

Results: : Resveratrol significantly inhibited HIF-1α accumulation in ARPE19 cells in a dose dependent manner. Suppression of HIF-1α by resveratol resulted in decrease in VEGF expression at both mRNA and secretion levels. Resveratrol inhibited HIF-1α accumulation by interfering PI3k/Akt signaling pathway. Pretreatment of the ARPE19 cells with MG132 increased ubiquitinated HIF-1α protein.

Conclusions: : Resveratrol inhibits HIF-1α and VEGF through Akt phosphorylation in ARPE19, suggesting its potential therapeutic value in the management of AMD.

Keywords: retinal degenerations: cell biology • age-related macular degeneration • hypoxia