Roosevelt University, Biological, Chemical, and Physcial Sciences, Chicago, IL 60605
Wnt signal transduction pathway, first identified in Drosophila melanogaster, has been shown to be involved in a number of cell processes, including proliferation, differentiation and death in mammalian cells. In addition, alteration of Wnt signaling has been implicated in a number of disease pathologies including human cancers. Our overall goal is to determine the possible role of Wnt signaling pathways in glaucoma pathology through the examination of these factors in trabecular meshwork (TM) cells. The TM, a tissue essential in the outflow of aqueous humor from the anterior portion of the eye, is considered to play an important role in maintaining intraocular pressure, a known risk factor for glaucoma. In this study, we used both bovine and human TM cell cultures to investigate the expression of Wnt signal transduction factors. Total RNA was isolated from TM cultures and cDNA was prepared by reverse transcriptase PCR. Expression of Wnt and Wnt-related genes in these samples was determined by PCR analysis using gene specific primers. In normal TM, we found the expression of various Wnt related genes such as LRP 5, LRP 6, Dkk1, APC, and beta-catenin. In addition to looking at expression under normal conditions, TM cultures were treated with H2O2 to induce oxidative stress as previous studies have suggested that oxidative damage may be an important step in the pathogenesis of primary open-angle glaucoma. TM cell cultures were treated with 1mM H2O2 for either 10 or 30 minutes. Control cells were not treated. Analysis of Wnt and Wnt-related genes using these samples indicated that their expressions changed during oxidative stress. Specifically, Wnt 5a gene expression was observed during oxidative stress at the 10 minute time point as opposed to no expression in the control. In contrast, beta-cateninexpression was down-regulated during oxidative stress. These preliminary results suggest that an alteration in Wnt expression patterns in response to oxidative stress in TM cells may play a role in glaucoma pathology. Future experiments will focus on the further elucidation of the role of Wnt signal transduction in TM cells and its possible relationship to glaucoma pathology.
K. Wentz-Hunter was supported by a Roosevelt University Summer Research Grant, 2007.
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