NF-kappaB regulates phagocytic NADPH oxidase by inducing the expression of gp91phox.
The superoxide-generating phagocytic NADPH oxidase is an important component of the innate immune response against microbial agents, and is involved in shaping the cellular response to a variety of physiological and pathological signals. One of the downstream targets of NADPH oxidase-derived radicals is the ubiquitous transcription factor NF-kappaB, which controls the expression of a large array of genes involved in immune function and cell survival. Here we show that NF-kappaB itself is a key factor in controlling NADPH oxidase expression and function. In monocytic and microglial cell lines, the expression of the NADPH oxidase subunit gp91(phox) was induced by lipopolysaccharide/interferon gamma treatment and was inhibited in cells constitutively expressing IkappaBalpha. Furthermore, inducible reactive oxygen species production was inhibited in IkappaBalpha overexpressing cells. gp91(phox) expression was very low in RelA(-/-) fibroblasts and could be induced by reconstituting these cells with p65/RelA. Thus, gp91(phox) expression is dependent on the presence of p65/RelA. We also found that gp91(phox) transcription is dependent on NF-kappaB and we identified two potential cis-acting elements in the murine gp91(phox) promoter that control NF-kappaB-dependent regulation. The findings raise the possibility of a positive feedback loop in which NF-kappaB activation by oxidative stress leads to further radical production via NADPH oxidase.
Anrather
Josef
J
Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10021, USA. joa2006@med.cornell.edu
Racchumi
Gianfranco
G
Iadecola
Costantino
C
D000818:Animals; D002460:Cell Line; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D008070:Lipopolysaccharides / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000378:metabolism; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D010587:Phagocytosis / Q000502:physiology*; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D051996:Transcription Factor RelA; D007371:Interferon-gamma; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases