title: Interleukin-6 production by human monocytes treated with granulocyte-macrophage colony-stimulating factor in the presence of lipopolysaccharide of oral microorganisms.
abstract: This study focused on the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) and lipopolysaccharide of the putative periodontal pathogens Porphyromonas gingivalis or Fusobacterium nucleatum on IL-6 production by THP-1 cells (a human monocytic cell line). Resting THP-1 cells were alternatively treated with GM-CSF (50 IU/ml) and lipopolysaccharide of P. gingivalis or F. nucleatum, in varying concentrations for varying time periods. IL-6 production in supernatant fluids of treated cells was evaluated by an enzyme-linked immunosorbent assay (ELISA) and a reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate gene expression. Untreated THP-1 cells did not produce IL-6 as determined by ELISA. RT-PCR also failed to detect IL-6 mRNA in untreated THP-1 cells, indicating that IL-6 was not constitutively produced. After stimulation of THP-1 cells with lipopolysaccharide of F. nucleatum or P. gingivalis, IL-6 was produced, peaking at 4 h (200-300 pg/ml) and thereafter sharply declining by 8 h. When GM-CSF was added together with lipopolysaccharide of P. gingivalis or F. nucleatum, there was a synergistic quantitative increase in production of IL-6 as measured by ELISA as compared with lipopolysaccharide alone. IL-6 mRNA was detected by RT-PCR, 15 min after stimulation with lipopolysaccharide of either P. gingivalis or F. nucleatum. GM-CSF supplementation with lipopolysaccharide of P. gingivalis shortened the transcription of IL-6 mRNA to 5 min, a shift which was not observed with lipopolysaccharide of F. nucleatum, possibly indicating a different mechanism of initiation of transcription. Production of IL-6 by GM-CSF-treated THP-1 cells in the presence of lipopolysaccharide of oral microorganisms may provide a model for studying the role of macrophages in acute and chronic periodontal diseases, including the clinical periodontal exacerbation as observed in chemotherapy patients receiving GM-CSF for bone marrow recovery.
authors: Department of Oral Medicine, Dental School, University of Maryland, Baltimore, USA.
authors: A A
authors: AA
authors: Baqui
authors: T F
authors: TF
authors: Meiller
authors: J J
authors: JJ
authors: Chon
authors: B F
authors: BF
authors: Turng
authors: W A
authors: WA
authors: Falkler
mesh_terms: D000704:Analysis of Variance; D016967:Fusobacterium nucleatum / Q000737:chemistry / Q000276:immunology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D010510:Periodontal Diseases / Q000276:immunology; D016966:Porphyromonas gingivalis / Q000737:chemistry / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D018417:Th1 Cells / Q000187:drug effects* / Q000378:metabolism
chemical_list: D015850:Interleukin-6; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D016178:Granulocyte-Macrophage Colony-Stimulating Factor