HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Conley, S. M. Articles by Stamer, W. D. Search for Related Content PubMed PubMed Citation Articles by Conley, S. M. Articles by Stamer, W. D.

Selenium’s Effects on MMP-2 and TIMP-1 Secretion by Human Trabecular Meshwork Cells

¹From the Departments of Ophthalmology and ²Epidemiology, University of Arizona, Tucson, Arizona.

PURPOSE. Because of the observed increase in incidence of glaucoma among some individuals taking selenium as a dietary supplement, the present study was undertaken to investigate mechanisms of selenium-induced changes in homeostasis of human trabecular meshwork (HTM) cells. Specifically, the impact of selenium on matrix metalloproteinases (MMPs), their inhibitors (tissue inhibitors of metalloproteinases; TIMPs), and the second messengers that regulate MMP expression was investigated in an HTM cell culture model.

METHODS. HTM cell cultures were treated with an organic selenium compound (methyl seleninic acid), and changes in secretion and activity of MMPs and TIMPs were analyzed by Western blot and zymography. Changes in extracellular-signal–related kinases 1 and 2 (ERK1/2) and phospho-ERK1/2 levels were monitored by Western blot analysis of whole-cell lysates prepared from selenium-treated cells. Photographs of cultures over time were used to document selenium-induced changes in cell morphology.

RESULTS. Treatment of HTM cells with selenium for 24 hours at doses ranging from 1 to 10 µM caused a dose-dependent decrease in the secretion of MMP-2 and TIMP-1. Treatment for 6 hours revealed a significant decrease in MMP-2 and TIMP-1 at the highest dose. MMP-1, -3, and -9 and TIMP-2 were either not detected or their secretion was not consistently influenced by selenium treatment. Selenium treatment caused a significant decrease in ERK1/2 phosphorylation, but no change in overall ERK protein levels. Selenium treatment resulted in dose-dependent, reversible changes in HTM cell–matrix associations.

CONCLUSIONS. Selenium-induced changes in MMP-2/TIMP-1 secretion may alter the balance of extracellular matrix turnover in the conventional outflow pathway and cause an increase in intraocular pressure that eventually leads to glaucoma.

This article has been cited by other articles:

				K. Sanka, R. Maddala, D. L. Epstein, and P. V. Rao Influence of Actin Cytoskeletal Integrity on Matrix Metalloproteinase-2 Activation in Cultured Human Trabecular Meshwork Cells Invest. Ophthalmol. Vis. Sci., May 1, 2007; 48(5): 2105 - 2114. [Abstract] [Full Text] [PDF]

				Y. F. Njie, A. Kumar, Z. Qiao, L. Zhong, and Z.-H. Song Noladin Ether Acts on Trabecular Meshwork Cannabinoid (CB1) Receptors to Enhance Aqueous Humor Outflow Facility Invest. Ophthalmol. Vis. Sci., May 1, 2006; 47(5): 1999 - 2005. [Abstract] [Full Text] [PDF]