The role of nuclear factor-kappa B in interleukin-8 expression by human adenoidal fibroblasts.
OBJECTIVE
The production of cytokines by adenoids is known to be associated with inflammation of nasopharynx and the pathogenesis of otitis media with effusion. However, the role of adenoids in producing inflammatory cytokines such as interleukin-8 (IL-8) is not yet clear. In the present study, expression of IL-8 in adenoidal fibroblasts was investigated at the level of transcription factors. Further, the effects of clarithromycin, a 14-member ring macrolide, on IL-8 gene expression and nuclear factor-kappa B (NF-kappa B) activation in adenoidal fibroblasts were evaluated.


METHODS
In vitro study for the production of inflammatory cytokine from human adenoidal fibroblasts.


METHODS
Adenoidal fibroblasts were incubated with nontypeable Haemophilus influenzae endotoxin or interleukin-1 beta. Then the expression of IL-8 and the influence of NF-kappa B inhibitor and clarithromycin were evaluated. Interleukin-8 protein production was assessed by ELISA, and IL-8 messenger RNA production was measured by Northern blot analysis and reverse transcriptase-polymerase chain reaction. Activation of NF-kappa B and inhibition of its activation were determined by electrophoretic mobility shift assay.


RESULTS
The expression of both IL-8 protein and messenger RNA in adenoidal fibroblasts was enhanced by Haemophilus influenzae endotoxin and interleukin-1 beta and was positively correlated with increases in NF-kappa B activity. Treatment of cells with the NF-kappa B inhibitor N-tosyl-(L)-phenylalanine chloromethyl ketone, as well as with clarithromycin, reduced expression of IL-8 and NF-kappa B activity in a dose-dependent manner.


CONCLUSIONS
Results suggest that adenoidal fibroblasts produce IL-8 in response to endotoxin through NF-kappa B activation. The inhibitory effects of clarithromycin on NF-kappa B activation and IL-8 production in adenoidal fibroblasts might explain, in part, the mechanism of this drug in improving otitis media with effusion.
Takaki
Minoru
M
Department of Otolarynology, Faculty of Medicine, Kagoshima University, Sakuragaoka, Japan.
Ushikai
Masoto
M
Deguchi
Kohji
K
Nishimoto
Kengo
K
Matsune
Shoji
S
Kurono
Yuichi
Y
D000234:Adenoids / Q000166:cytology*; D017291:Clarithromycin / Q000494:pharmacology; D024202:Electrophoretic Mobility Shift Assay; D004731:Endotoxins / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism*; D006193:Haemophilus influenzae; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014108:Tosylphenylalanyl Chloromethyl Ketone / Q000494:pharmacology; D015533:Transcriptional Activation
D004731:Endotoxins; D007375:Interleukin-1; D016209:Interleukin-8; D016328:NF-kappa B; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D014108:Tosylphenylalanyl Chloromethyl Ketone; D017291:Clarithromycin