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Y. Chen, M.J. Kelley, T. Acott; DNA Microarray Analysis of Gene Expression in Tabecular Meshwork Cells in Response to TNF and IL–1 . Invest. Ophthalmol. Vis. Sci. 2005;46(13):1349.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Previous studies showed that interleukin–1 (IL–1) and tumor necrosis factor α (TNFα) jointly mediate the trabecular meshwork (TM) response to therapeutic laser trabeculoplasty for glaucoma. TM cells respond by producing matrix metalloproteinase–3 (MMP3) which adjust the aqueous outflow resistance, partially by initiating extracellular matrix (ECM) turnover. To further define this process, cDNA microarrays were used to evaluate gene expression in response to TNFα and IL–1α treatment of TM cells. Methods: Porcine TM cells were treated with TNFα or IL–1α for 12, 24 or 48 hours. Total RNA was isolated and human cDNA microarrays were used to measure expression levels of approximately 16,000 genes in 3 independent experiments. Stringent biological and statistical criteria were used to rank genes in terms of the magnitude and significance of treatment effects. Selected microarray expression differences were confirmed by quantitative RT–PCR and Western blot. Results: These microarray experiments broadly confirmed previously published data from other tissues on general gene expression regulated by IL–1α and TNFα. Both treatments induced an inflammatory response pattern, including induction of genes for chemokines (CCL2, CXCL12, and CCL5), inflammatory mediators (PLAU), and cell surface membrane proteins (ephrin–B1). IL–1α significantly increased 868 and decreased 276 genes, while TNFα increased 1739 and decreased 634 genes at one or more time points. Many of the gene expression changes were in ECM and ECM regulatory genes. IL–1α and TNFα had similar effects on some genes and different effects on others. Expression of MMP–3, MMP–12, MMP–13, urokinase plasminogen activator, collagen XVA1, tenascin C, glypican 3, VCAM–1 and VEGFC was increased by both IL–1α and TNFα treatment. Expression of MMP–19 was increased by TNFα treatment, while MMP–27 was increased by IL–1α treatment. Several ECM or cellular receptors, such as CD44, syndecan 1 & 2, matrix Gla protein and SPARC were decreased by both treatments. Mimecan was increased by IL–1α treatment, but decreased by TNFα treatment. Conclusions: IL–1α and TNFα each activate expression of a distinct set of genes in porcine TM cells, and a series of ECM biosynthetic and reorganization steps have been identified. Moreover, our studies highlight the unique roles that TNFα and IL–1α play at the cellular level. The homeostatic adjustment of the trabecular outflow resistance after therapeutic laser trabeculoplasty mediated by IL–1α and TNFα appears to be a very complex process.
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