Retinal pigment epithelial cells display specific transcriptional responses upon TNF-α stimulation

Abstract

BACKGROUND/AIMS: Tumour necrosis factor-α (TNF-α) is a key mediator of ocular inflammation and its interaction with the retinal pigment epithelium (RPE) may be a driving force in vitreoretinal disorders such as age-related macular degeneration, proliferative vitreoretinopathy (PVR) and diabetic retinopathy. Under inflammatory conditions, the ability of RPE cells to maintain the blood-retinal barrier and immune privilege may be lost and proliferation of RPE cells is facilitated. To gain insight into the effects of TNF-α on RPE cells, a gene expression study was performed. METHODS: ARPE-19 and HT-29 cells were stimulated with 50 ng/mL TNF-α for 6 h. Gene expression patterns were compared between stimulated and control cells using whole genome gene expression arrays. Data were analysed using Partek and OmniViz and validated using quantitative RT-PCR. Functional annotation analysis was performed using Ingenuity and DAVID. RESULTS: A total of 97 genes were uniquely modulated by TNF-α in ARPE-19 cells compared with HT-29 cells (86 upregulated and 11 downregulated). Most commonly affected biological processes were apoptosis, cell motility and cell signalling. The highest upregulated gene was EFNA1. Among the downregulated genes were transcription factors implicated in ocular development (SIX3, PAX6) and modulation of p53-mediated apoptosis (CITED2). CONCLUSIONS: This study provides insight into the unique responses of RPE cells to TNF-α stimulation and suggests a role for genes involved in apoptosis and retinal epithelial development. These findings contribute to our understanding of the behaviour of RPE cells under inflammatory conditions and the crucial role of RPE cells in vitreoretinal diseases.