Negative regulation of IL-1beta production at the level of transcription in macrophages stimulated with LPS.
The IL-1beta gene is rapidly and transiently expressed in LPS-stimulated macrophages. While several studies have addressed the molecular basis of LPS-induced transcriptional activity, the mechanisms which underlie the subsequent decrease in IL-1beta gene expression have not been as extensively examined. In this regard, we found that the characteristic decrease in IL-1beta production after LPS stimulation could be abrogated by treatment of macrophages with the protein kinase inhibitor staurosporine. This inhibitor mediated an enhancement of IL-1beta production which was first evident 8-12 h after LPS stimulation and continued at peak levels for the rest of the incubation period (24 h). IL-1beta production was correlated with the level of mRNA specific for the cytokine. Staurosporine also mediated an enhancement of LPS-induced IL-1beta promoter activity measured in RAW 264.7 cells transiently transfected with an IL-1beta reporter plasmid. This increase paralleled the enhancement of IL-1beta mRNA by staurosporine both in intensity and time after LPS stimulation, suggesting that the negative regulation of IL-1beta is exerted primarily at the level of transcription. This regulation may be at least partially due to an observed inhibition of nitric oxide production by staurosporine in LPS-activated macrophages, which was correlated with enhanced IL-1beta production. However, the intensity of the observed effects suggested that additional staurosporine-sensitive regulatory mechanisms are in operation at the level of promoter activity.
Schilling
D
D
Department of Microbiology and Genetics, Darmstadt University of Technology, Schnittspahnstrasse 10, D-64287 Darmstadt, Germany. dschilli@bio.tu-darmstadt.de
Beissert
T
T
Fenton
M J
MJ
Nixdorff
K
K
D000818:Animals; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D011401:Promoter Regions, Genetic / Q000187:drug effects; D020871:RNA Stability; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D013997:Time Factors; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D004791:Enzyme Inhibitors; D007375:Interleukin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D019311:Staurosporine