Abstract
Purpose :
In steroid-induced glaucoma (SIG), increased outflow resistance in the trabecular meshwork (TM) is responsible for ocular hypertension (OHT), which is associated with dysregulated turnover of the extracellular matrix (ECM). Importantly, >90% of people with primary open-angle glaucoma (POAG) develop OHT after steroid treatment. The purpose of the present study was to compare ECM gene expression profiles of primary TM cells isolated from healthy and glaucomatous human donor eyes in response to glucocorticoid treatment.
Methods :
TM cells isolated from normal and glaucomatous human donor eyes were plated at confluence and cultured in 1% FBS medium for one week. Differentiated cells were treated with vehicle or Dexamethasone (Dex, 100μM) for an additional week. RNA was collected, cDNA libraries were synthesized, and their extracellular matrix and adhesion molecule profiles were analyzed using RT2 Profiler PCR Array. Comparative quantification algorithms were employed to create appropriate standard curves to generate heat maps for visual comparisons of cells and conditions. Values below a fold change expression of 0.5 (decreased) or above 1.5 (increased), based on established standards for Real Time PCR, were used for analysis.
Results :
Of the 84 ECM genes tested, the expression of 45 genes remained unchanged between Dex treated or untreated cells in both healthy and POAG TM cell lines. However, the expression of 23 genes changed in a donor-dependent manner in response to Dex treatment. Of note, 10 genes, including genes encoding several matrix metalloproteinases (MMPs), had directionally equivalent responses in both Dex treated groups, independent of disease state (healthy or POAG). For example, MMP1, 2, 3, and 16 decreased in response to Dex in healthy and POAG TM. Finally, 6 genes including MMP7, Contactin 1, Collagen XV, Integrin beta 4, Selectin E, and Versican were differentially regulated by Dex treatment in POAG versus normal TM cells.
Conclusions :
Our results indicate differential expression of genes involved in scaffolding and regulation of ECM turnover post-steroid treatment in human TM cells from POAG versus non-POAG donors. Genes identified here are potential targets for understanding the underlying mechanisms of increased incidence of steroid-induced OHT in POAG patients.
This is a 2020 ARVO Annual Meeting abstract.