Abstract
Purpose: :
Angiogenesis plays a key role in several diseases involving RPE cells including age-related macular degeneration (AMD). The compound 3,4 dihydroxyphenyl ethanol (DPE) is a polyphenol present in virgin olive oil known to have antioxidative properties. Previous studies have investigated DPE and its ability to prevent cardiovascular diseases. The purpose of this study is to investigate the effects of DPE on retinal pigment epithelial (RPE) cells, as well as how DPE modulates various genes involved in angiogenesis.
Methods: :
Sub-lethal levels of DPE were determined by exposing retinal pigment epithelial cells (ARPE-19) to varying doses and performing a TOX-6 proliferation assay (Sigma). ARPE-19 cells were then treated with the sub-lethal dose (0.1µM DPE) for 24 hours in culture before RNA extraction (RNeasy Mini Kit, Qiagen). RT-PCR was then used to determine the expression of VEGFA in treated (0.1µM DPE) and control ARPE-19 cells. Finally, a PCR array was used to analyze at the effects of DPE in ARPE-19 cells on 84 genes involved in modulating angiogenesis (RT² Profiler PCR Array System, SABiosciences). Transcripts with a greater than three-fold change were considered significant.
Results: :
A proliferation assay demonstrated that a concentration of 0.1µM DPE resulted in the least amount of toxicity in the ARPE-19 cell line. RT-PCR demonstrated that VEGFA was decreased in DPE treated cells compared to the control. Lastly, the PCR array confirmed a general decrease in many genes associated with angiogenesis. The most significant include: ANPEP, EFNA3, EREG, FGFR3, and PLXDC1 which were down regulated by -3.33, -4.14, -3.03, -4.41, and -4.66 cycles respectively.
Conclusions: :
To the best of our knowledge, this is the first time that the effects of DPE on RPE cells have been investigated with respect to angiogenesis. We have shown that DPE is capable of reducing the expression of genes that are crucial for the angiogenic process. Considering the implications of angiogenesis in AMD, these results provide the framework for future studies to further investigate a potential therapeutic role for DPE.
Keywords: age-related macular degeneration • antioxidants • gene/expression