Dexamethasone Increases Cdc42 Expression in Human TM-1 Cells. (March 2015)

• Record Type: Journal Article
• Authors: Qiu, Xuan; Wu, Kaili; Lin, Xianchai; Liu, Qian; Ye, Yiming; Yu, Minbin
• Is Part Of: Current eye research. Volume 40:Number 3(2015:Mar.)
• Page Start: 290
• Page End: 299
• Publication Date: 2015-03
• Subjects: Ophthalmology -- Periodicals; Eye -- Diseases -- Periodicals; Ophthalmology -- Periodicals; 573.88
• DOI: 10.3109/02713683.2014.922191
• Languages: English
• ISSNs: 0271-3683

Abstract

<abstract> <title>Abstract</title> <p> <italic>Purpose</italic>: 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.</p> <p> <italic>Methods</italic>: TM-1 cells were cultured <italic>in vitro</italic>. The cultures were treated with DEX at 10<sup>−6</sup> and 10<sup>−7</sup> 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.</p> <p> <italic>Results</italic>: 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.</p> <p> <italic>Conclusions</italic>: DEX increases Cdc42 expression in TM-1. This may represent a potential mechanism of DEX-induced HTM cytoskeletal rearrangement.</p> </abstract>