Gene Expression Profile in a Novel Cell Type in Primary Cultures of Human Trabecular Meshwork

Abstract

Abstract: : Purpose: A small number of cells with distinct growth patterns and ultrastructural features can be observed to resume growth a few weeks after replicative senescence has been reached in primary cultures of human trabecular meshwork (HTM) cells. The purpose of this study is to investigate the gene expression profile of this potentially new cell type found in primary cultures of HTM cells. Methods: Total RNA (900 ng) was extracted from an isolated colony of this cell type and used to generate an antisense RNA probe by the T7-based linear amplification method (RiboAmp, Arcturus). This probe was hybridized to an Affymetrix U95Av2 human array, and the expression profile was compared to those from primary cultures of HTM and Schlemm's canal (SC) cells at passage three. Results: Gene array analysis showed a pattern of gene expression in these cells that was clearly different from those of HTM, SC cells, or fibroblasts. This pattern includes the lack of expression of genes like Chitinase-3-like-1 (expressed in HTM), Tissue Inhibitor of Metalloproteinases-3 (expressed in SC), and Interstitial Collagenase (expressed in fibroblasts). In contrast, high expression of Ankyrin G (absent in SC cells and very weakly expressed in HTM cell cultures), and Breast Epithelial Antigen BA46 (not expressed in fibroblasts) was observed. Conclusions: Gene expression profile analysis provides further evidence of the differences between this cell type and HTM, SC cells, and fibroblasts, consistent with previous observations of differences in morphology, ultrastructure and pattern of growth. Based on all these observations we conclude that these cells could derive from the Schwalbe’s cells that have been postulated to be responsible for cell regeneration in the HTM.

Keywords: molecular biology • trabecular meshwork • regeneration