Muramyl Dipeptide (MDP) Regulates the Production of Matrix Metalloproteinase-3 by Human Dental Pulp Fibroblast-like Cells

Abstract

Nucleotide-binding oligomerization domain 2, which is constitutively expressed in human dental pulp fibroblast-like cells (hDPFs), plays a role in pulpal immune responses by sensing muramyl dipeptide (MDP) from bacteria. Matrix metalloproteinase-3 (MMP-3) is abundantly expressed in acute pulpitis and acts as a mediator of the healing of dental pulp as an anti-inflammatory and regenerative factor. In the present study, we investigated the involvement of the ERK1/2 signaling pathway in MMP-3 production by MDP-stimulated hDPFs. MDP was not cytotoxic against hDPFs and did not affect their proliferation. A stimulation with MDP enhanced MMP-3 production and ERK1/2 phosphorylation. The ERK1/2 signaling pathway was involved in the production of MMP-3 by MDP-stimulated hDPFs. These results suggest that the induction of MMP-3 production by MDP-stimulated hDPFs has an anti-inflammatory function by degrading inflammatory cytokines.