Abstract
Abstract: :
Purpose: To study the expression of human neuronal olfactomedin (hOlfA) in the intact trabecular meshwork (TM) tissue in response to high pressure (HP). To investigate whether expression of hOlfA and TIGR/MYOC are co-regulated. Methods: Cultured anterior segments from human donors were perfused for 24 hrs at a constant flow of 3 µl/min. After reaching baseline values, the flow of one eye was raised to achieve an increase in pressure of 30 mmHg for a period of 1 h, 4 and 7 days. The flow of the contralateral eye was maintained at 3 µl/min as a control. At the end of the experiment, anterior segments were placed into RNA Later, their TM's dissected and RNA extracted. Primary human TM (HTM) cells were infected with an adenovirus containing wild type TIGR/MYOC cDNA (AdhTIGR3) and harvested 48 h post-infection. Non infected cells served as controls. Expression of hOlfA and TIGR/MYOC was determined by Relative Quantitative PCR (RQ-PCR) using target gene different exon primers and a primer/competimer ratio of 18S controls. Quantitation was then done using a scanning gel dock optical density system. Results: After 1 h HP, expressions of TIGR/MYOC and hOlfA were not significantly different than those in the contralateral control. After 4d HP, hOlfA expression increased 2.2 ± 0.3 fold (n=3, p=0.04), while TIGR/MYOC was not increased. At 7 d HP, hOlfA expression increased 3.3 ± 0.3 fold (n=3, p=0.01) and TIGR/MYOC increased 1.6 ± 0.1 fold (n=3, p=0.02). HTM cells infected with AdhTIG3 did not show a significant change in the expression of hOlfA while the increase for TIGR/MYOC was 90.4 ± 7.2 fold (n=3, p=0.007). Conclusion: hOlfA is regulated by elevated pressure in the same time dependent manner as TIGR/MYOC. However, expression of hOlfA is not a direct consequence of elevated levels of TIGR/MYOC. These results indicate that in addition to TIGR/MYOC, at least one other member of the olfactomedin protein family may play an important role in the stress response to elevated intraocular pressure in the trabecular meshwork.
Keywords: 417 gene/expression • 601 trabecular meshwork • 444 intraocular pressure