S-I Tanabe1, C Bodet, D Grenier. 1. Groupe de Recherche en Ecologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada.
Abstract
BACKGROUND AND OBJECTIVE: Treponema denticola is a key pathogen associated with periodontitis, a chronic inflammatory disease affecting tooth-supporting tissues. In the present study, we investigated the response of human macrophage-like cells to stimulation by peptidoglycan isolated from T. denticola. We also studied the effect of the peptidoglycan preparation on the phosphorylation state of kinases. MATERIAL AND METHODS: Monoblastic leukemia cells (U937 strain) were differentiated into adherent macrophage-like cells using phorbol myristic acid prior to being stimulated for 6 or 24 h with various amounts of T. denticola peptidoglycan. Secreted inflammatory mediators were quantified by enzyme-linked immunosorbent assays. The phosphorylation state of kinases was determined by immunoblotting. RESULTS: The T. denticola peptidoglycan preparation, which was non-toxic for macrophage-like U937 leukemia cells at the concentration used, significantly increased, in a dose-dependent manner, the secretion of the pro-inflammatory cytokines tumor necrosis factor alpha, interleukin-1beta and interleukin-6. It also increased the secretion of two potent chemokines, interleukin-8 (IL-8) and regulated on activation normal T cell expressed and secreted (RANTES). T. denticola peptidoglycan also induced a significant increase in the secretion of prostaglandin E(2) and matrix metalloproteinase 9 by macrophage-like cells. The phosphorylation state of several kinases, including extracellular regulated protein-serine kinase 2 (+99%), G protein-coupled receptor-serine kinase 2 (+50%), Yes-related protein-tyrosine kinase (+44%) and extracellular regulated protein-serine kinase 1 (+30%) also increased following stimulation with the peptidoglycan preparation. CONCLUSION: T. denticola peptidoglycan activates intracellular signaling pathways, leading to an increased production of inflammatory mediators by macrophage-like cells.
BACKGROUND AND OBJECTIVE:Treponema denticola is a key pathogen associated with periodontitis, a chronic inflammatory disease affecting tooth-supporting tissues. In the present study, we investigated the response of human macrophage-like cells to stimulation by peptidoglycan isolated from T. denticola. We also studied the effect of the peptidoglycan preparation on the phosphorylation state of kinases. MATERIAL AND METHODS:Monoblastic leukemia cells (U937 strain) were differentiated into adherent macrophage-like cells using phorbol myristic acid prior to being stimulated for 6 or 24 h with various amounts of T. denticola peptidoglycan. Secreted inflammatory mediators were quantified by enzyme-linked immunosorbent assays. The phosphorylation state of kinases was determined by immunoblotting. RESULTS: The T. denticola peptidoglycan preparation, which was non-toxic for macrophage-like U937 leukemia cells at the concentration used, significantly increased, in a dose-dependent manner, the secretion of the pro-inflammatory cytokines tumor necrosis factor alpha, interleukin-1beta and interleukin-6. It also increased the secretion of two potent chemokines, interleukin-8 (IL-8) and regulated on activation normal T cell expressed and secreted (RANTES). T. denticola peptidoglycan also induced a significant increase in the secretion of prostaglandin E(2) and matrix metalloproteinase 9 by macrophage-like cells. The phosphorylation state of several kinases, including extracellular regulated protein-serine kinase 2 (+99%), G protein-coupled receptor-serine kinase 2 (+50%), Yes-related protein-tyrosine kinase (+44%) and extracellular regulated protein-serine kinase 1 (+30%) also increased following stimulation with the peptidoglycan preparation. CONCLUSION:T. denticola peptidoglycan activates intracellular signaling pathways, leading to an increased production of inflammatory mediators by macrophage-like cells.
Authors: Annie N Hinson; Colin G Hawkes; Christopher S Blake; Zackary R Fitzsimonds; Bin Zhu; Gregory Buck; Richard J Lamont; Daniel P Miller Journal: Infect Immun Date: 2022-08-30 Impact factor: 3.609