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FW Rozsa, KM Scott, ME Higashi, T Guckian, JE Richards, JR Polansky; Effect of Glucose Exposure on Gene Expression in Cultured HTM Cells . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1049.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: to evaluate expression of TIGR/MYOC and other genes in cultured human trabecular cells following exposure to varying glucose concentrations and durations of treatment. Potential differences between the responses seen in cultures from older vs younger donors are of interest because of the age dependence of elevated IOP and POAG. Methods: Early passage primary culture HTM cells derived from non-glaucomatous eyes from three young (12, 16, and 17 years) and three older (40, 49, and 49 years) individuals were grown in culture in the presence of 1 g/L glucose until confluent, stable cultures were obtained. These were then incubated in culture media containing 1 g/L or 4.5 g/L glucose for 1, 6, 24, 48, or 168 hours. Replicate real-time PCR was performed on RNA samples from each time point for the 16 year old and one of the 49 year olds, using intron-spanning primers to TIGR/MYOC, and several standard housekeeping genes. Diluted plasmid containing the cloned TIGR/MYOC was used as an external reference. RNA was obtained for all six donors at the 24 hour time point for use in microarray assays and differential gene comparisons for each individual. Results: Glucose stimulation of TIGR/MYOC expression in one cell line peaked at 6 hours exposure with more than seven-fold increase relative to the untreated cells and remained elevated for 7 days. In contrast, cells from another donor showed a slight decrease in TIGR/MYOC expression over the entire time course. Comparison of different donors, including genetic differences and any possible age-associated differences in glucose induction, using microarray assays and real-time PCR will be presented. Conclusion: Comparisons of glucose effects on TIGR/MYOC gene expression with levels of expression of other genes need to be examined under the different treatment conditions in the older vs younger cultures, and using ex vivo and physiological models, to assess the importance of our observations in outflow regulation and glaucoma. It remains to be determined whether TIGR/MYOC is induced by glucose via a shared pathway common to multiple TIGR-inducing agents, and evaluations of specific biochemical pathways (e.g. aldose reductase inhibition) compared with effects of osmotic agents need to be investigated.
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