Mechanisms Underlying Enterococcus faecalis-Induced Tumor Necrosis Factor-alpha Production in Macrophages
International Journal of Oral Biology
; : 43-49, 2010.
Article
de En
| WPRIM
| ID: wpr-142964
Bibliothèque responsable:
WPRO
ABSTRACT
Enterococcus faecalis, a gram-positive bacterium, has been implicated in endodontic infections, particularly in chronic apical periodontitis. Proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), are involved in the pathogenesis of these apical lesions. E. faecalis has been reported to stimulate macrophages to produce TNF-alpha. The present study investigated the mechanisms involved in TNF-alpha production by a murine macrophage cell line, RAW 264.7 in response to exposure to E. faecalis. Both live and heat-killed E. faecalis induced high levels of gene expression and protein release of TNF-alpha. Treatment of RAW 264.7 cells with cytochalasin D, an inhibitor of endocytosis, prevented the mRNA up-regulation of TNF-alpha by E. faecalis. In addition, antioxidant treatment reduced TNF-alpha production to baseline levels. Inhibition of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinase also significantly attenuated E. faecalis-induced TNF-alpha expression by RAW 264.7 cells. Furthermore, activation of NF-kappaB and AP-1 in RAW 264.7 cells was also stimulated by E. faecalis. These results suggest that the phagocytic uptake of bacteria is necessary for the induction of TNF-alpha in E. faecalis-stimulated macrophages, and that the underlying intracellular signaling pathways involve reactive oxygen species, ERK, p38 MAP kinase, NF-kappaB, and AP-1.
Mots clés
Texte intégral:
1
Indice:
WPRIM
Sujet Principal:
Parodontite périapicale
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Phosphotransferases
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Bactéries
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ARN messager
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Cytochalasine D
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Expression des gènes
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Régulation positive
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Lignée cellulaire
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Cytokines
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Facteur de transcription NF-kappa B
langue:
En
Texte intégral:
International Journal of Oral Biology
Année:
2010
Type:
Article