IL-10 inhibits transcription of cytokine genes in human peripheral blood mononuclear cells.
Upon addition of LPS to human PBMCs, IL-1 beta, IL-6, and TNF-alpha were released in the culture media in a time-dependent manner. Cytokine release began 2 h after LPS addition and maximal release of all three cytokines was observed between 6 and 8 h. Northern analysis revealed that, for each cytokine, mRNA accumulation preceded protein release. When added either 2 h before or at the same time as LPS, IL-10 inhibited both the cytokine release and mRNA accumulation almost completely. Similar inhibition was observed when IL-10 was added 2 h after LPS, a time point that coincided with the onset of the rapid burst of cytokine mRNA accumulation. The inhibitory activity of IL-10 was abrogated by cycloheximide, suggesting an involvement of newly synthesized proteins in IL-10 action. By using nuclear run-on transcription assays, we have found that IL-10 inhibited transcription of all three cytokine genes in LPS-stimulated PBMCs. In contrast, IL-10 moderately enhanced degradation of IL-6 mRNA, but not of mRNAs for IL-1 beta and TNF-alpha. Thus, the present study provides the first evidence that, in human PBMCs, IL-10 inhibits cytokine synthesis by acting mainly at the level of cytokine gene transcription.
Wang
P
P
Schering-Plough Research Institute, Kenilworth, NJ 07033.
Wu
P
P
Siegel
M I
MI
Egan
R W
RW
Billah
M M
MM
D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics; D016753:Interleukin-10 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10