Endothelin-1 regulates the expression of interleukin-1ß in inflamed periodontal tissues

Objectives: We recently demonstrated that endothelin-1 (ET-1) was strongly expressed in inflamed gingival tissues, but the biological role of ET-1 in gingival tissue remains unknown. This study focused on the relationship between ET-1 and interleukin-1ß (IL-1ß), an important cytokine during the periodontal inflammatory process. We determined the protein levels of ET-1 and IL-1ß in gingival tissues from patients and examined whether ET-1 could regulate the expression of the IL-1ß gene and protein in oral epithelial cells and fibroblasts. Methods: There was a significant correlation between the levels of ET-1 and IL-1ß in 26 gingival tissues, as determined by ELISA. Following the confirmation of two specific ET-1 receptors (ETA and ETB receptors) on the cells, the effects of ET-1 stimulation on IL-1ß mRNA and protein expression were evaluated by RT-PCR and ELISA, respectively. Results: The IL-1ß mRNA and protein levels were enhanced by ET-1 stimulation in a dose-dependent manner, and the enhancement of IL-1ß was inhibited by ETA or ETB receptor antagonists. Conclusions: These findings indicate that ET-1 is involved in the regulation of IL-1ß expression in gingival tissues and suggest that ET-1 signalling to the cells may be a therapeutic target for treating IL-1ß-dependent inflammatory responses.