Estrogen effects on VEGF-A expression in Human Retinal Pigment Epithelial Cells

Abstract

Purpose : Estrogen has different effects on various tissues depending on the concentration and cell type. It has been shown that 17β-estradiol (E2) can modulate inflammatory response and decrease expression of IL-6 in adult human retinal pigment epithelial (ARPE-19) cells. Tumor Necrotic Factor Alpha (TNF-α) is increased in many retinal diseases involving chronic inflammation and it induces expression of Vascular Endothelial Growth Factor (VEGF)-A by ARPE-19 cells. The purpose of this study is to assess effects of distinct concentrations of E2 on the VEGF-A expression induced by TNF-α on ARPE-19 cells.

Methods : ARPE-19 cells were obtained from the American Type Culture Collection (ATCC) and grown in 12 well culture plates. The cells were divided in 3 groups: cell medium only; cell medium + 1mM E2; cell medium + 2mM E2. After twenty-four hours of incubation, TNF-α (10ng/mL) was added to the medium and the cells were incubated for six more hours. Cells were harvested and the expression level of VEGF-A was assessed in all groups by qPCR using actin as a reference gene.

Results : Compared to the group pre-treated with medium only, we observed a 36% reduction on the expression of VEGF-A in the cell group pre-treated with medium + E2 1mM (p=0.03). The difference observed was not statistically significant (p=0.20) when comparing the group pre-treated with medium + E2 2mM with the group pre-treated with medium only.

Conclusions : Treatment of the ARPE-19 cells with 1mM E2 reduced the impact of TNF-α on the production of VEGF-A. The reduction observed at a higher E2 concentration was not significant. Systemic and local levels of estrogens may play an important role in preventing the progression of retinal diseases involving chronic inflammation and VEGF-A expression. The differential E2 response needs further investigation.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.