Differential roles for NF-kappa B in endotoxin and oxygen induction of interleukin-8 in the macrophage.
The alveolar macrophage is an important source of interleukin (IL)-8 during pulmonary injury. The IL-8 gene promoter sequence contains nuclear factor (NF)-kappa B, NF-IL6, and activator protein (AP)-1 binding sequences. These sites may have differing regulatory roles in hyperoxia-exposed macrophages than in those stimulated by bacterial lipopolysaccharide (LPS). U-937 and THP-1 macrophage-like cells were exposed to air-5% CO2 or 95% O2-5% CO2, with or without 1.0 microg/ml of LPS, and transfected with an IL-8 promoter-reporter containing NF-kappa B, NF-IL6, or AP-1 mutations. Hyperoxia and LPS caused additive increases in IL-8 production by U-937 cells, whereas THP-1 cells responded only to LPS. An NF-kappa B mutation ablated baseline and O2- and LPS-stimulated reporter activity in both cell lines, whereas NF-IL6 mutations had little effect. An AP-1 mutation had an intermediate effect. LPS, but not hyperoxia, stimulated nuclear translocation of NF-kappa B in both cell lines. Pharmacological blockade of NF-kappa B nuclear translocation ablated LPS-, but not hyperoxia-, stimulated IL-8 production. Although an intact promoter NF-kappa B site is crucial to macrophage IL-8 production, only LPS-stimulated production appears to require additional nuclear translocation of NF-kappa B.
D'Angio
Carl T
CT
Departmentof Pediatrics, Strong Children's Research Center, University of Rochester School of Medicine, NY 14642, USA. carl_dangio@urmc.rochester.edu
LoMonaco
Michael B
MB
Johnston
Carl J
CJ
Reed
Christina K
CK
Finkelstein
Jacob N
JN
D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology*; D016209:Interleukin-8 / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D018808:Transcription Factor AP-1 / Q000378:metabolism; D020298:U937 Cells
D022782:CCAAT-Enhancer-Binding Protein-beta; D016209:Interleukin-8; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D010100:Oxygen