IL-12 is dysregulated in macrophages from IRF-1 and IRF-2 knockout mice.
Macrophages derived from IFN-regulatory factor-1 (IRF-1) and IRF-2 knockout (-/-) and wild-type (+/+) mice were utilized to examine the role of these transcription factors in the regulation of IL-12 mRNA and protein expression. Induction of IL-12 p40 mRNA by LPS was markedly diminished in both IRF-1(-/-) and IRF-2(-/-) macrophages. In contrast, IRF-1(-/-), but not IRF-2(-/-), macrophages exhibited impaired LPS-induced IL-12 p35 mRNA expression. The ability of IFN-gamma to augment LPS-induced IL-12 p40 mRNA further when both stimuli were present simultaneously was significantly diminished in both IRF-1(-/-) and IRF-2(-/-) macrophages, with the most profound impairment observed for IRF-1(-/-) macrophages. Reductions in IL-12 mRNA expression after stimulation with LPS or LPS plus IFN-gamma were accompanied by substantial reductions in IL-12 p40 and IL-12 p70 protein in both IRF-1(-/-) and IRF-2(-/-) macrophages. Priming IRF-1(-/-) and IRF-2(-/-) macrophages with IFN-gamma for 24 h before LPS treatment partially restored impaired IL-12 mRNA and protein production in both IRF-1(-/-) and IRF-2(-/-) macrophages. Depressed IL-12 levels were paralleled by significant reductions in IFN-gamma mRNA expression in IRF-1(-/-) and IRF-2(-/-) macrophages. These results indicate that both IRF-1 and IRF-2 are critical transcription factors in the regulation of macrophage IL-12 and consequently IFN-gamma production.
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
C A
CA
Salkowski
K
K
Kopydlowski
J
J
Blanco
M J
MJ
Cody
R
R
McNally
S N
SN
Vogel
D000818:Animals; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000235:genetics*; D050856:Interferon Regulatory Factor-1; D050836:Interferon Regulatory Factor-2; D050835:Interferon Regulatory Factors; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology; D018664:Interleukin-12 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000276:immunology* / Q000378:metabolism* / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D012097:Repressor Proteins / Q000096:biosynthesis; D013211:Staphylococcus aureus / Q000276:immunology; D014157:Transcription Factors; D015854:Up-Regulation / Q000276:immunology; D015054:Zymosan / Q000276:immunology; D000099185:Interferon Regulatory Factor-8
D004268:DNA-Binding Proteins; D050856:Interferon Regulatory Factor-1; D050836:Interferon Regulatory Factor-2; D050835:Interferon Regulatory Factors; D007371:Interferon-gamma; D018664:Interleukin-12; D008070:Lipopolysaccharides; D010750:Phosphoproteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; D015054:Zymosan; D000099185:Interferon Regulatory Factor-8; C494258:Irf1 protein, mouse; C494230:Irf2 protein, mouse