[Regulation of tumor necrosis factor-alpha mRNA expression in murine peritoneal macrophages].
The expression of tumor necrosis factor-alpha (TNF-alpha) mRNA in murine inflammatory peritoneal macrophages (M phi) was studied with a sensitive liquid hybridization method. Upon exposure to 10-1000 ng/ml of lipopolysaccharide (LPS), M phi were induced to express TNF-alpha mRNA in a dose-dependent manner. mRNA was detectable within 1 h after stimulation, peaked at about 2 h and then gradually declined. A 10 min treatment with LPS was enough to stimulate the maximal level of TNF-alpha mRNA, as determined in a 2 h period. Although calcium ionophore A23187 and macrophage activating factor (MAF) (both can activate M phi to mediate tumoricidal activity) did not induce TNF-alpha mRNA expression by themselves, they did act synergistically with LPS. Treatment of M phi with retinoic acid strongly inhibited LPS-induced TNF-alpha mRNA expression, whereas trifluoperazine had an opposite effect. Cycloheximide not only synergized with LPS but also induced TNF-alpha mRNA expression by itself. In contrast, actinomycin D completely blocked LPS-induced TNF-alpha gene activation. These findings indicate that LPS-induced TNF-alpha mRNA expression is not solely due to an increase in intracellular free calcium ion and is independent of the protein kinase C pathway of signal transduction. In addition, TNF gene activity may be regulated by short-lived protein repressor(s).
Dong
Z
Z
Institute of Oncology, Beijing.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D016215:Macrophage-Activating Factors / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015345:Oligonucleotide Probes; D010529:Peritoneal Cavity / Q000166:cytology; D012333:RNA, Messenger / Q000032:analysis*; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis* / Q000235:genetics
D008070:Lipopolysaccharides; D016215:Macrophage-Activating Factors; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000001:Calcimycin