Time-Dependent Glucocorticoid-Induced Transcriptomic Changes in Human Trabecular Meshwork and Schlemm's Canal Cells

To identify the transcriptomic changes induced by dexamethasone (DEX) in trabecular meshwork (TM) and Schlemm's canal endothelial (SCE) cells with RNA sequencing (RNA-seq).

Human TM (n = 10) and SCE cell strains (n = 5) were isolated from healthy donor eyes and exposed to 100-nM DEX and vehicle (control). Three DEX exposure times were evaluated: 1 hour, 6 hours, and 2 days. RNA-seq was performed on the Illumina TruSeq platform, and gene expression was quantified using featureCounts. The DESeq2 paired samples (treated and untreated) test was applied to identify genes transcriptionally responsive to DEX (DEGs) at a false discovery rate < 0.05. Gene Set Enrichment Analysis (GSEA) was performed on DEGs, and the DEGs were tested for an association with primary open-angle glaucoma (POAG) and intraocular pressure (IOP).

Nine TM and four SCE strains passed quality control. After 2-day DEX exposures, there were 857 and 2086 DEGs in TM and SCE cells, respectively. Of these, 411 genes were differentially expressed in both TM and SCE cells, including FKBP5 (17.3 fold change; P = 6.9 × 10-53) and FAM107A (25.1 fold change; P = 4.0 × 10-240), the most significant DEGs after 2-day DEX exposure in TM and SCE cells, respectively. The 2-day DEX DEGs in TM and SCE cells were enriched in Gene Ontology (GO) cell adhesion, extracellular matrix, and response to stimulus (P < 3.7 × 10-6). Early-response DEGs were enriched in immune-related processes. Thirteen DEGs in TM were significant at all three time points, including PER1. LTBP2 is a TM-only DEG and FAM105A is a SCE-only DEG associated with IOP and POAG risk.

This study identified candidate genes and pathways for glucocorticoid-induced ocular hypertension which can be further explored in human genetic analyses.