Nuclear factor kappa B mediates interleukin-8 production in eosinophils.
BACKGROUND
Recent reports indicate that in response to various stimuli, eosinophils produce a variety of cytokines (e.g. IL-8) which play pivotal roles in allergic inflammation. In that regard, the transcription factor, nuclear factor, Kappa B (NF-kappaB), is an important activator of tumor-necrosis-factor-alpha (TNF-alpha)-induced IL-8 gene expression in monocytes, lymphocytes and neutrophils. We therefore investigated the role played by NF-kappaB in cytokine production induced by stimulation of eosinophils with the proinflammatory cytokines, granulocyte-monocyte colony-stimulating factor (GM-CSF) and TNF-alpha.


METHODS
Peripheral blood samples were obtained from human subjects with slight to moderate eosinophilia. NF-kappaB activation elicited by exposing cells to GM-CSF and/or TNF-alpha was investigated using immunohistochemistry and gel shift assays. To functionally assess the effects of NF-kappaB translocation, IL-8 production was also examined using an enzyme-linked immunosorbent assay.


RESULTS
Stimulation of eosinophils with GM-CSF + TNF-alpha induced significant increases in the synthesis and secretion of IL-8 which were associated with translocation of NF-kappaB p50 into the nucleus. The binding of NF-kappaB to the DNA was verified by the gel shift assays. IL-8 production was significantly inhibited by N-acetyl-L-cysteine, FK506 and MG-132, inhibitors of NF-kappaB activation and translocation.


CONCLUSIONS
On the basis of our findings, we conclude that activation and translocation of NF-kappaB plays a crucial role in the signal-transduction pathway leading to the synthesis and release of IL-8 by eosinophils.
Yamashita
N
N
Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan. naomiya@med.teikyo-u.ac.jp
Koizumi
H
H
Murata
M
M
Mano
K
K
Ohta
K
K
D000111:Acetylcysteine / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003720:Densitometry; D004586:Electrophoresis; D004797:Enzyme-Linked Immunosorbent Assay; D004804:Eosinophils / Q000187:drug effects / Q000378:metabolism*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis*; D007976:Leupeptins / Q000494:pharmacology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D016559:Tacrolimus / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D015853:Cysteine Proteinase Inhibitors; D007166:Immunosuppressive Agents; D016209:Interleukin-8; D007976:Leupeptins; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D016559:Tacrolimus; D000111:Acetylcysteine