Endotoxin and interferon-gamma differentially regulate the transcriptional levels of proto-oncogenes and cytokine genes during the differentiation of colony-stimulating factor type-1-derived macrophages.
The expression of cytokine genes for interleukin-1 (IL-1) (alpha and beta) and tumour necrosis factor-alpha (TNF-alpha), along with the proto-oncogenes c-fos, c-fms and c-myc, was examined by nuclear run-off and Northern blot analysis during in vitro differentiation of colony-stimulating factor type-1 (CSF-1)-derived bone marrow macrophages (BMDM). Constitutive transcription of c-myc was maximal on day 3 and decreased with differentiation. Constitutive transcription of c-fms and c-fos was similar at all times examined. In contrast, the steady-state mRNA levels were maximal on day 5 for c-myc and day 7 for c-fms and c-fos. Thirty minutes after endotoxin (lipopolysaccharide; LPS) stimulation, there was a rapid increase in run-off transcription rates for c-myc in day 3-day 9 BMDM, with maximal levels observed in day 7 BMDM. c-fms transcription was maximally induced within 1 hr by LPS in day 3 and day 5 BMDM. LPS induced transcription of c-fos to equivalent levels in day 3-day 9 BMDM. LPS stimulation augmented steady-state mRNA levels for c-myc, c-fms and c-fos. Maximal induction of c-myc was observed in day 3 BMDM. c-fos and c-fms were both maximally induced in day 5 and day 7 BMDM. Interferon-gamma (IFN-gamma) had no effect on transcription of the proto-oncogenes examined. In contrast to the proto-oncogenes, peak levels of run-off transcription for IL-1 alpha and IL-1 beta genes were observed 1-2 hr after LPS stimulation for day 3, day 5 and day 7 BMDM. The kinetics of LPS-induced steady-state mRNA accumulation of IL-1 alpha and IL-1 beta were similar to the kinetics of run-off transcription. Constitutive transcription of TNF-alpha was observed on all days of differentiation. LPS and IFN-gamma both enhanced run-off transcription of the TNF-alpha gene; however, LPS had a more pronounced effect. The kinetics of induction of TNF-alpha transcription paralleled the kinetics of steady-state TNF-alpha mRNA accumulation. IFN-gamma resulted in secretion of TNF-alpha in day 5, day 7, and day 9 BMDM after 4-8 hr of stimulation. Day 3 BMDM had little, if any, secreted TNF-alpha activity.(ABSTRACT TRUNCATED AT 400 WORDS)
Myers
M J
MJ
Department of Animal Sciences, University of Illinois, Urbana, USA.
Ghildyal
N
N
Schook
L B
LB
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D016207:Cytokines / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D007371:Interferon-gamma / Q000494:pharmacology*; D007375:Interleukin-1 / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D016173:Macrophage Colony-Stimulating Factor; D008264:Macrophages / Q000166:cytology; D051379:Mice; D008809:Mice, Inbred C3H; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics; D011519:Proto-Oncogenes; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D016207:Cytokines; D007375:Interleukin-1; D008070:Lipopolysaccharides; D016760:Proto-Oncogene Proteins c-fos; D016271:Proto-Oncogene Proteins c-myc; D014409:Tumor Necrosis Factor-alpha; D016173:Macrophage Colony-Stimulating Factor; D007371:Interferon-gamma; D016186:Receptor, Macrophage Colony-Stimulating Factor