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Abstract #57280 Published in IGR 16-2
Dexamethasone Increases Cdc42 Expression in Human TM-1 Cells
Qiu X; Wu K; Lin X; Liu Q; Ye Y; Yu MCurrent Eye Research 2014; 0: 1-10
PURPOSE: Changes in the cytoskeletal organization of the human trabecular meshwork (HTM) is thought to be responsible for primary open-angle glaucoma (POAG) pathologies. Cdc42 is a Rho GTPase; Rho GTPases are important modulatory agents of the cytoskeleton. This study aimed to investigate the effects of dexamethasone (DEX) on Cdc42 in a transformed HTM cell line, TM-1 to understand the molecular pathologies underlying POAG. METHODS: TM-1 cells were cultured in vitro. The cultures were treated with DEX at 10(-6) and 10(-7) M for 1-4 days. Cdc42 was silenced using small interfering RNA (siRNA). The expression levels of Cdc42 in the TM-1 cells were measured using reverse transcription (RT)-PCR, western blotting analysis and immunofluorescence. Its downstream effectors, p21-activated kinase phosphorylation (phospho-PAK) and myosin light chain kinase (MLCK), were measured using western blotting analysis. In addition, the F-actin of TM-1 cells was stained using phalloidin. RESULTS: The mRNA and protein levels of Cdc42 showed an increase in TM-1 cells with DEX treatment and a decrease in TM-1 cells transfected with Cdc42 siRNA. Moreover, phospho-PAK levels increased, whereas MLCK levels appeared to decrease, with DEX treatment. The F-actin of DEX-treated TM-1 cells displayed a rearrangement. Cdc42 siRNA decreased the expression of Cdc42 and its related proteins, resulting in an attenuation of the effects of DEX on Cdc42 and F-actin organization in TM-1 cells. CONCLUSIONS: DEX increases Cdc42 expression in TM-1. This may represent a potential mechanism of DEX-induced HTM cytoskeletal rearrangement.
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Classification:
9.4.1 Steroid-induced glaucoma (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)
3.6 Cellular biology (Part of: 3 Laboratory methods)
3.5 Molecular biology incl. SiRNA (Part of: 3 Laboratory methods)
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
