Protease-activated receptor-2 activation enhances epithelial wound healing via epidermal growth factor receptor.

Abstract

The intestinal barrier function relies on the presence of a single layer of epithelial cells. Barrier dysfunction is associated with the inflammatory bowel diseases (IBD). Understanding the mechanisms involved in intestinal wound healing in order to sustain the barrier function has a great therapeutic potential. Activation of protease-activated receptor-2 (PAR2) induces COX-2 expression in intestinal epithelial cells via EGFR transactivation. COX-2 is well known for its protective effects in the gastrointestinal tract. Therefore, we hypothesized that PAR-2 activation induces a wound healing response in intestinal epithelial cells through COX-2-derived lipid mediators and EGFR transactivation. Immunofluorescence and calcium assay were used to characterize CMT-93 mouse colonic epithelial cell line for PAR2 expression and its activity, respectively. Treatment with PAR2 activating peptide 2-furoyl-LIGRLO-NH₂ (2fLI), but not by its inactive reverse-sequence peptide (2fO) enhanced wound closure in scratch wounded monolayers. The EGFR tyrosine kinase inhibitor (PD153035), broad-spectrum matrix metalloproteinase inhibitor (GM6001) and Src tyrosine kinase inhibitor (PP2) inhibited PAR2-induced wound healing. However, PAR2 activation did not induce COX-2 expression in CMT-93 cells and inhibition of COX-2 by COX-2 selective inhibitor (NS-398) did not alter PAR2-induced wound healing. In conclusion, PAR2 activation drives wound healing in CMT-93 cells via EGFR transactivation. Matrix metalloproteinases and Src tyrosine kinase activity may involve in EGFR transactivation and PAR2-induced wound healing is independent of COX-2 activity. These findings provide a mechanism whereby PAR2 can participate in the resolution of intestinal wounds in gastrointestinal inflammatory diseases.