DNA Methylation Analysis of Human Trabecular Meshwork Cells During Dexamethasone Stimulation.

Purpose: We investigated the changes in the DNA methylation status of cultured human trabecular meshwork (TM) cells during glucocorticoid exposure, and evaluated the effect of epigenetic modification on the gene expression of TM cells.

Methods: Three batches of primary culture TM cells were treated with and without 100 nM dexamethasone (DEX) for 14 days. Genome-wide methylation analysis was done using Illumina 450 K methylation chips. The gene expression profile of the TM cells also was examined. The epigenetic effect of DEX stimulation on gene expression in TM cells was further verified by treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) and subsequent real-time PCR analysis.

Results: After DEX stimulation, we found demethylated cytosine-phosphate-guanine (CpG) sites within the FKBP5, ZBTB16, and SCNN1A gene promoter regions with increases of corresponding gene expression for all three TM batches, and methylated CpG sites within the ARSI, HIC1, GREM2, and MATN2 gene promoter regions with decreases of corresponding of gene expression for all three batches. Inhibition of DNA methylation by 5-aza-dC treatment induced a further increase of FKBP5 and SCNN1A mRNA expression under DEX stimulation.

Conclusions: The DEX stimulation induces alteration of the DNA methylation status in human TM cells. Epigenetic modification could affect the TM gene expression profile.