Abstract
Abstract: :
Purpose: Mutations in optineurin (OPTN) have been linked to families with primary open-angle glaucoma. Here we determined the expression profile for this novel gene in the trabecular meshwork (TM) under conditions mimicking physiological pressure. We studied the OPTN expression in response to three factors known to be associated with the development of glaucoma: elevated intraocular pressure (IOP), tumor necrosis factor-α (TNFα) and dexamethasone (DEX). Methods: Anterior segment pairs from non-glaucomatous post-mortem human eyes were perfused for 24 h at constant flow of 3 µl/min with serum-free tissue culture medium. For elevated pressure experiments, the flow in one eye was raised to obtain a ΔP of 35 mmHg for either 6 h, 2, 4 or 7 days. The flow of the contralateral, control eye was maintained at 3 µl/min. For drug treatments, both eyes were maintained at their basal flow rate. One eye of each pair was perfused with medium containing either 25 ng/ml TNFα for 3 days or 0.1 µM DEX for 7 days. At the end of each experiment, TM cDNA libraries were constructed and expression of OPTN and 18S RNA of the treated eyes versus that of their paired controls was determined by relative quantative RT-PCR. Results: OPTN gene expression was up-regulated after 6 h of high IOP (8.2 ± 3.9%, P = 0.07) which increased and became significant after 2 days (9.6% ± 4.2%, P = 0.03), 4 days (40.2% ± 4.5%, P = 0.00001) and 7 days (55.6% ± 3.3%, P = 0.0002) (n = 9 for each time point). OPTN expression was also induced 2.3 ± 0.05-fold (P = 0.008) in TMs treated with TNFα (n = 6) and 2.6 ± 0.12-fold (P = 0.0002) in those treated with DEX (n = 9). Conclusions: These findings demonstrate that OPTN belongs to the trabecular meshwork transcriptome that responds to insults involved in glaucomatous occurrences and support the notion that OPTN may be part of a general protective mechanism present in the cells of the outflow pathway.
Keywords: gene/expression • outflow: trabecular meshwork • trabecular meshwork