Inhibition of Intestinal Epithelial Wound Healing through Protease-Activated Receptor-2 Activation in Caco2 Cells.

Abstract

The mechanisms of epithelial wound healing are not completely understood, especially in the context of proteases and their receptors. It was recently shown that activation of protease-activated receptor-2 (PAR2) on intestinal epithelial cells induced the expression of cyclooxygenase-2 (COX-2), which has protective functions in the gastrointestinal tract. It was hypothesized that PAR2-induced COX-2 could enhance wound healing in intestinal epithelial cells. Caco2 cells were used to model epithelial wound healing of circular wounds. Cellular proliferation was studied with a 5-ethynyl-2'-deoxyuridine assay, and migration was studied during wound healing in the absence of proliferation. Immunofluorescence was used to visualize E-cadherin and F-actin, and the cellular transcription profile during wound healing and PAR2 activation was explored with RNA sequencing. PAR2 activation inhibited Caco2 wound healing by reducing cell migration, independently of COX-2 activity. Interestingly, even though migration was reduced, proliferation was increased. When the actin dynamics and cell-cell junctions were investigated, PAR2 activation was found to induce actin cabling and prevent the internalization of E-cadherin. To further investigate the effect of PAR2 on transcriptionally dependent wound healing, RNA sequencing was performed. This analysis revealed that PAR2 activation, in the absence of wounding, induced a similar transcriptional profile compared with wounding alone. These findings represent a novel effect of PAR2 activation on the mechanisms of epithelial cell wound healing that could influence the resolution of intestinal inflammation.