Protease-activated receptor 2 mediates interleukin-8 and intercellular adhesion molecule-1 expression in response to Aggregatibacter actinomycetemcomitans.

INTRODUCTION We investigated the mechanisms by which extracts of Aggregatibacter actinomycetemcomitans affect the inflammatory response in gingival epithelial cells. METHODS Human gingival cells (Ca9-22) were cultured in bacterial extracts prepared from A. actinomycetemcomitans ATCC 29522. The cells were pretreated with protease inhibitors or transfected with small interfering RNA (siRNA) specific for protease-activated receptor 2 (PAR-2). RESULTS The pretreatment of cells with serine protease inhibitors significantly inhibited A. actinomycetemcomitans extract-induced expression of interleukin-8 (IL-8) and intercellular adhesion molecule-1 (ICAM-1) at both the messenger RNA and protein levels. In addition, A. actinomycetemcomitans extract-induced IL-8 and ICAM-1 expression was significantly decreased in PAR-2/siRNA-transfected cells. CONCLUSIONS A. actinomycetemcomitans extract-induced IL-8 and ICAM-1 expression in gingival epithelial cells is mediated by PAR-2.