The effect of Rho-associated protein kinase inhibitor on monkey Schlemm's canal endothelial cells.

Purpose: To investigate the effect of a specific inhibitor of Rho-associated protein kinase, Y-27632, on monkey Schlemm's canal endothelial (SCE) cells.

Methods: SCE cells were isolated from cynomolgus monkey eyes. The effects of Y-27632 on aqueous outflow facility were evaluated using enucleated monkey eyes and a constant-pressure perfusion system. The effect of Y-27632 on the barrier function of the confluent SCE-cell monolayer was evaluated by measuring transendothelial electrical resistance (TEER) and fluorescein permeability. Y-27632-induced changes in the intracellular localization of ZO-1, claudin-5, β-catenin, pan-cadherin, and filamentous actin (F-actin) were examined by immunofluorescence. Gene-expression changes induced by Y-27632 were analyzed with microarray, and the functional categories of changed genes were identified by gene ontology analysis. The concentrations of intracellular calcium ions were estimated using Fluo-4/AM and a fluorescence microscope system.

Results: Y-27632 significantly increased the outflow facility and the number of associated giant vacuoles, decreased TEER of the SCE-cell monolayer, and increased the transendothelial flux of fluorescein. Y-27632 disrupted ZO-1 and claudin-5 expression in a confluent SCE-cell monolayer. Among 12,544 genes, Y-27632 treatment increased the expression of 57 genes and decreased the expression of 15 genes. Gene ontology analysis revealed that changed genes were related to various cellular functions, including regulation of calcium ion transport into the cytosol. Y-27632 partially diminished the A23187-induced increase in intracellular calcium ions.

Conclusions: Y-27632 increased the permeability of the SCE-cell monolayer in association with disruption of the tight junction, F-actin depolymerization, and changes in various cell functions, including calcium transfer.