Up-regulation of COX2 expression by uni-axial cyclic stretch in human lung fibroblast cells

The effect of uni-axial cyclic mechanical stretch on the expression of cyclooxygenases (COX) was investigated in a human lung fibroblast cell line (TIG-1). In response to uni-axial cyclic stretch, the level of COX2 mRNA significantly increased and peaked at 3 h (9.09 ± 3.82-fold, mean ± standard error, n = 6, compared with that at 1 h). The level of the expression of COX2 protein peaked at 6 h, whereas the level of COX1 protein was not significantly changed. The involvement of stretch-activated (SA) channel was investigated in the stretch-induced COX2 production. The application of Gd³⁺, a blocker for SA channel, or the removal of extracellular Ca²⁺ inhibited the production of COX2 mRNA without any effect on the production of COX1 or GAPDH mRNA. These data strongly suggest that COX2 expression is up-regulated by uni-axial cyclic stretch via the activation of SA channel in human lung fibroblasts.