House Dust Mite Extract Induces PLC/IP3-dependent Ca2+ Signaling and IL-8 Expression in Human Gingival Epithelial Cells

ABSTRACT

The gingival epithelium of the oral cavity is constantly exposed to exogenous stimuli such as bacterial toxins, allergens, and thermal changes. These exogenous stimuli are resisted by innate host defense in gingival epithelial cells. However, it is unclear exactly how the exogenous stimuli affect detrimentally on the human gingival epithelial cells. Here, we investigated whether the allergen, such as house dust mite (HDM) extract, is linked to Ca2+ signaling and proinflammatory cytokine expression in primary cultured human gingival epithelial cells. HDM extract induced an increase in intracellular Ca2+ concentration ([Ca2+]i) in a dose-dependent manner. Extracellular Ca2+ depletion did not affected on the HDM extract-induced increase in [Ca2+]i. The HDM extract-induced increase in [Ca2+]i was abolished by the treatment with U73122 and 2-APB, which are inhibitors of phospholipase C (PLC) and inositol 1,4,5-trisphosphate (IP3) receptor. Moreover, HDM extract induced the mRNA expression of pro-inflammatory cytokine, interleukin (IL)-8. These results suggest that HDM extract triggers PLC/IP3-dependent Ca2+ signaling and IL-8 mRNA expression in primary cultured human gingival epithelial cells.