Genetic deficiency of NADPH oxidase does not diminish, but rather enhances, LPS-induced acute inflammatory responses in vivo.
Reactive oxygen species (ROS) and oxidative stress are thought to play a central role in the etiology of cell dysfunction and tissue damage in sepsis. However, there is limited and controversial evidence from in vivo studies that ROS mediate cell signaling processes that elicit acute inflammatory responses during sepsis. Because NADPH oxidase is one of the main cellular sources of ROS, we investigated the role of this enzyme in lipopolysaccharide (LPS)-induced acute inflammation in vivo, utilizing mice deficient in the gp91(phox) or p47(phox) subunits of NADPH oxidase. Age-and body weight-matched C57BL/6J wild-type (WT) and gp91(phox-/-) and p47(phox-/-) mice were injected ip with 50 microg LPS or saline vehicle and sacrificed at various time points up to 24 h. We found that LPS-induced acute inflammatory responses in serum and tissues were not significantly diminished in gp91(phox-/-) and p47(phox-/-) mice compared to WT mice. Rather, genetic deficiency of NADPH oxidase was associated with enhanced gene expression of inflammatory mediators and increased neutrophil recruitment to lung and heart. Furthermore, no protection from LPS-induced septic death was observed in either knockout strain. Our findings suggest that NADPH oxidase-mediated ROS production and cellular redox signaling do not promote, but instead limit, LPS-induced acute inflammatory responses in vivo.
Zhang
Wei-Jian
WJ
Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA. weijian.zhang@oregonstate.edu
Wei
Hao
H
Frei
Balz
B
D000818:Animals; D002465:Cell Movement / Q000276:immunology; D016207:Cytokines / Q000097:blood; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000172:deficiency / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D018805:Sepsis / Q000235:genetics / Q000276:immunology* / Q000401:mortality; D015398:Signal Transduction; D016019:Survival Analysis; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism
D016207:Cytokines; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1