Prevotella intermedia lipopolysaccharide stimulates release of tumor necrosis factor-alpha through mitogen-activated protein kinase signaling pathways in monocyte-derived macrophages.
The purpose of this study was to investigate the effects of lipopolysaccharide from Prevotella intermedia, a major cause of inflammatory periodontal disease, on the production of tumor necrosis factor (TNF)-alpha and the expression of TNF-alpha mRNA in differentiated THP-1 cells, a human monocytic cell line. The potential involvement of the three main mitogen-activated protein kinase (MAPK) signaling pathways in the induction of TNF-alpha production was also investigated. Lipopolysaccharide from P. intermedia ATCC 25611 was prepared by the standard hot phenol-water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. It was found that P. intermedia lipopolysaccharide can induce TNF-alpha mRNA expression and stimulate the release of TNF-alpha in differentiated THP-1 cells without additional stimuli. Treatment of the cells with P. intermedia lipopolysaccharide resulted in a simultaneous activation of three MAPKs [extracellular signal-related kinase 1/2 (ERK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2) and p38]. Pretreatment of the cells with MAPK inhibitors effectively suppressed P. intermedia lipopolysaccharide-induced TNF-alpha production without affecting the expression of TNF-alpha mRNA. These data thus provided good evidence that the MAPK signaling pathways are required for the regulation of P. intermedia lipopolysaccharide-induced TNF-alpha synthesis at the level of translation more than at the transcriptional level.
Kim
Sung-Jo
SJ
Department of Periodontology, College of Dentistry, Pusan National University, Busan, Korea. sungjokim@pusan.ac.kr
Choi
Eun-Young
EY
Kim
Eun Gyung
EG
Shin
Su-Hwa
SH
Lee
Ju-Youn
JY
Choi
Jeom-Il
JI
Choi
In-Soon
IS
D015153:Blotting, Western; D002460:Cell Line; D015870:Gene Expression; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology*; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology*; D018713:Prevotella intermedia / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha