Purpose: The aim of this study was to examine the expression of genes related to the Wnt signaling pathway, such as beta-catenin (CTNNB1) and secreted frizzled-related protein-1 (sFRP1), in human trabecular meshwork (TM) cells. In addition, the effect of oxidative stress on Wnt signaling was evaluated.
Methods: All experiments were conducted using second- or third-passaged human TM cells. cDNA was prepared from total RNA extracted from cells by means of reverse transcription. PCR was then performed to determine the presence of Wnt genes. For oxidative stress, TM cells were treated with 1 mM of H(2)O(2) for 30 min. Actin staining was carried out to verify cell response to oxidative stress. Western blotting was used to measure Wnt-related protein levels after H(2)O(2) treatment.
Results: Positive PCR products were detected for a total of 25 Wnt and Wnt-related genes in human TM cells. Most of the genes identified belonged to the Wnt/beta-catenin pathway. Members of the beta-catenin-independent noncanonical pathways were also found. Oxidative stress did not result in significant changes in beta-catenin and sFRP1 protein levels.
Conclusions: Genes related to canonical and noncanonical Wnt pathways are expressed in human TM cells. It appears that all three Wnt pathways are operative in the TM system. Oxidative stress, while thought to play a role in the development of glaucoma, had little effect on the Wnt activity in TM cells.