Preexposure of murine macrophages to CpG-containing oligonucleotides results in nuclear factor kappaB p50 homodimer-associated hyporesponsiveness.
Surgery
; 132(2): 245-51, 2002 Aug.
Article
em En
| MEDLINE
| ID: mdl-12219019
ABSTRACT
BACKGROUND:
DNA containing the CpG motif is associated with immunomodulation of the innate immune response. Preexposure of macrophages to CpG DNA elicits a hyporesponsiveness to subsequent lipopolysaccharide (LPS) stimulation. We tested the hypothesis that this effect is due to decreased nuclear translocation of nuclear factor kappaB (NF-kappaB).METHODS:
Murine macrophage-like RAW 264.7 cells were incubated with 1.5 microg/mL CpG-containing oligonucleotides (CpG ODN) for 0.5 to 9 hours followed by restimulation with 1 microg/mL LPS for 20 minutes. Some cells were cotransfected with an NF-kappaB sensitive luciferase reporter construct and a control beta-gal plasmid. Cytoplasmic and nuclear extracts were assayed for NF-kappaB by electrophoretic mobility shift assay and supershift assays, for NF-kappaB, IkappaB and phospho-IkappaB by Western blot, for luciferase activity, and for p38, c-Jun NH(2)-terminal kinase, and extracellular signal-related kinase activity assay.RESULTS:
NF-kappaB functional activity was decreased as demonstrated by luciferase activity assay in the prolonged CpG ODN pretreatment groups. Unlike endotoxin tolerance, CpG ODN preexposure increased cytoplasmic phospho-IkappaB-alpha and did not abrogate mitogen-activated protein kinase activity.CONCLUSIONS:
In macrophages, exposure to CpG DNA increases expression of the inhibitory p50 NF-kappaB homodimer and decreases NF-kappaB activity without inhibition of IkappaB kinases. Mitogen-activated protein kinase activity remains intact. Understanding these interactions between different toll receptor ligands may provide insight into novel therapeutic modalities.
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Base de dados:
MEDLINE
Assunto principal:
Oligonucleotídeos
/
NF-kappa B
/
Ilhas de CpG
/
Proteínas I-kappa B
/
Macrófagos
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos