Effects of IL-10 and IL-4 on LPS-induced transcription factors (AP-1, NF-IL6 and NF-kappa B) which are involved in IL-6 regulation.
Interleukin-10 (IL-10), like IL-4, is known to inhibit cytokine expression in activated human monocytes. We showed that both IL-10 and IL-4 inhibit LPS-induced IL-6 mRNA and protein expression by inhibiting the transcription rate of the IL-6 gene. The strong inhibition of the IL-6 transcription rate prompted us to study the effect of IL-10 and IL-4 on the expression of transcription factors. We questioned whether or not IL-10 and IL-4 affected the expression of transcription factors that are known to be involved in the control of the IL-6 transcription rate, namely activator protein-1 (AP-1), nuclear factor IL-6 (NF-IL6), and nuclear factor kappa B (NF-kappaB). In electrophoretic mobility shift assays (EMSAs) we showed that IL-10 and IL-4 inhibited LPS-induced AP-1 binding activity. The inhibiting effect of IL-4 was slightly more pronounced than that of IL-10. Downregulation of LPS-induced AP-1 was accompanied, and thus possibly explained, by a reduced expression at mRNA level of the two major components of the AP-1 complex, namely c-fos and c-jun as determined by Northern experiments. Binding activity of NF-IL6 was also strongly inhibited by IL-4 whereas IL-10 showed no effect. NF-IL6 mRNA levels were not affected by IL-10 or IL-4, suggesting that IL-4 affects binding activity of preexisting NF-IL6. Neither IL-10 nor IL-4 inhibited LPS-induced NF-kappa B binding activity. In agreement with this finding, Northern experiments where p65 and p105 mRNA levels were determined, demonstrated that expression of these components of the NF-kappa B transcription factor were not affected by IL-10 or IL-4. Furthermore, neither IL-10 nor IL-4 showed any effect on I-kappa B mRNA expression as determined by Northern experiments. Thus, IL-10 and IL-4 similarly affect IL-6 expression. However, for IL-4 this was accompanied with a reduction of AP-1 and NF-IL6 binding activity whereas IL-10 only inhibited AP-1 binding activity.
Dokter
W H
WH
Department of Medicine, University of Groningen, The Netherlands.
Koopmans
S B
SB
Vellenga
E
E
D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D022762:CCAAT-Enhancer-Binding Proteins; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D006801:Humans; D016753:Interleukin-10 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D016328:NF-kappa B / Q000096:biosynthesis* / Q000378:metabolism; D009687:Nuclear Proteins / Q000096:biosynthesis*; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000096:biosynthesis*; D051841:Transcription Factor RelB; D014157:Transcription Factors / Q000096:biosynthesis*; D014158:Transcription, Genetic
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D011518:Proto-Oncogene Proteins; C497593:RELB protein, human; D011994:Recombinant Proteins; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D016753:Interleukin-10; D051841:Transcription Factor RelB; D015847:Interleukin-4