Interleukin (IL)-10 inhibits nuclear factor kappa B (NF kappa B) activation in human monocytes. IL-10 and IL-4 suppress cytokine synthesis by different mechanisms.
Our previous studies in human monocytes have demonstrated that interleukin (IL)-10 inhibits lipopolysaccharide (LPS)-stimulated production of inflammatory cytokines, IL-1 beta, IL-6, IL-8, and tumor necrosis factor (TNF)-alpha by blocking gene transcription. Using electrophoretic mobility shift assays (EMSA), we now show that, in monocytes stimulated with LPS or TNF alpha, IL-10 inhibits nuclear stimulation of nuclear factor kappa B (NF kappa B), a transcription factor involved in the expression of inflammatory cytokine genes. Several other transcription factors including NF-IL-6, AP-1, AP-2, GR, CREB, Oct-1, and Sp-1 are not affected by IL-10. This selective inhibition by IL-10 of NF kappa B activation occurs rapidly and in a dose-dependent manner and correlates well with IL-10's cytokine synthesis inhibitory activity in terms of both kinetics and dose responsiveness. Furthermore, compounds such as tosylphenylalanyl chloromethyl ketone and pyrrolidinedithiocarbamate that are known to selectively inhibit NF kappa B activation block cytokine gene transcription in LPS-stimulated monocytes. Taken together, these results suggest that inhibition of NF kappa B activation may be an important mechanism for IL-10 suppression of cytokine gene transcription in human monocytes. IL-4, another cytokine that inhibits cytokine mRNA accumulation in monocytes, shows little inhibitory effect on LPS-induced NF kappa B activation. Further examination reveals that, unlike IL-10, IL-4 enhances mRNA degradation and does not suppress cytokine gene transcription. These data indicate that IL-10 and IL-4 inhibit cytokine production by different mechanisms.
Wang
P
P
Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
Wu
P
P
Siegel
M I
MI
Egan
R W
RW
Billah
M M
MM
D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D016753:Interleukin-10 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D009000:Monocytes / Q000378:metabolism*; D016328:NF-kappa B / Q000037:antagonists & inhibitors*
D016207:Cytokines; D008070:Lipopolysaccharides; D016328:NF-kappa B; D016753:Interleukin-10; D015847:Interleukin-4