Purpose: To determine the levels of cross-linked actin networks (CLANs) in glaucoma compared to normal TM cells and to evaluate changes in the expression of cytoskeletal proteins in normal and dexamethasone-treated TM cells which may be associated with CLAN formation Methods: Microfilament organization was evaluated in 9 normal and 14 glaucomatous TM cell lines using rhodamine-phalloidin epifluorescence microscopy. Normal human TM cells were treated with or without DEX (0.1 uM) for 14 days, and cytoskeletal associated proteins were examined by Western immunoblot analysis. Results: An average of 29.6 +/- 9 0% and 60.8 +/- 9 1% of the glaucoma TM cells expressed CLANs in the absence and presence of DEX (respectively) compared to 5 1 +/- 5.7% and 47.4 +/- 9.7% of the normal TM cells (p < 0.001 and 0 01 between normal and glaucomatous cells, respectively). There was a 3fold increase in alpha-actinin expression and a 2-fold increase in metavinculin expression in the DEX-treated TM cells compared to controls. In contrast, there were no changes in the amounts of total actin, smooth muscle alpna-actin. or tropomyosin between DEX-treated and control TM cells. Conclusions: There is a significant increase in reorganized actin microfilaments in glaucomatous and in DEX-treated TM cells. The reorganization of the TM microfilaments and alterations in alpha-actinin and vinculin expression may provide important clues into the role of the TM cytoskeleton in glucocorticoid-induced ocular hypertension and glaucoma.
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - 1 Dec 1997|