Interleukin-17A stimulates migration of periodontal ligament fibroblasts via p38 MAPK/NF-κB -dependent MMP-1 expression.

Interleukin-17 (IL-17) is a cytokine secreted predominantly by Th17 cells. Although IL-17 is primarily associated with the induction of tissue inflammation, the other biological functions of IL-17, including its wound-healing functions, have yet to be thoroughly explored. Fibroblast proliferation and migration play essential roles in periodontal wound-healing responses. In this study, we report that IL-17A can increase the migration and expression of matrix metalloproteinase (MMP)-1 in human periodontal ligament (PDL) fibroblasts but has no effect on PDL fibroblast proliferation. IL-17A-induced MMP-1 expression led to cell migration, which was attenuated by pre-treatment with IL-17 receptor neutralizing antibody and small interfering RNA (siRNA) for MMP-1. The IL-17A-induced cell migration was also attenuated by its tissue inhibitor of matrix metalloproteinase (TIMP)-1. In addition, a p38 mitogen-activated protein kinase (MAPK) inhibitor (SB203580) inhibited IL-17A-induced increase of the migration and MMP-1 upregulation of PDL fibroblasts. The involvement of p38 MAPK in IL-17A-induced MMP-1 expression and cell migration was further confirmed by transfection of p38α siRNA. A nuclear factor kappaB (NF-κB) inhibitor (pyrrolidine dithiocarbamate) also suppressed the cell migration and MMP-1 expression enhanced by IL-17A. Moreover, transfection with p38α siRNA inhibited IL-17A-induced NF-κB nuclear translocation as well as NF-κB binding activity. Our results suggest that IL-17A enhances the migration of PDL fibroblasts by increasing MMP-1 expression through the IL-17 receptor, p38 MAPK, and NF-κB signal transduction pathways.