Cryptic O2- -generating NADPH oxidase in dendritic cells.
All the components of the O(2)(-)-generating NADPH oxidase typically found in neutrophils, namely a membrane-bound low potential flavocytochrome b and oxidase activation factors of cytosolic origin, are immunodetectable in murine dendritic cells (DCs). However, in contrast to neutrophils, DCs challenged with phorbol myristate acetate (PMA) can barely mount a significant respiratory burst. Nevertheless, DCs generate a substantial amount of O(2)(-) in the presence of PMA following preincubation with pro-inflammatory ligands such as lipopolysaccharide and pansorbin, and to a lesser extent with anti-CD40 or polyinosinic polycytidylic acid. We found that the virtual lack of the oxidase response to PMA alone is specifically controlled in DCs. Through the use of homologous and heterologous cell-free systems of oxidase activation, we showed the following: (1) a NADPH oxidase inhibitory factor is located in DC membranes; it exerts its effect on oxidase activation and not on the activated oxidase. (2) The inhibition is relieved by pretreatment of DC membranes with beta-octylglucoside (beta-OG). (3) The beta-OG-extracted inhibitory factor prevents the activation of neutrophil oxidase. (4) The inhibitory activity is lost after treatment of DC membranes with proteinase K or heating, which points to the protein nature of the inhibitory factor. Overall, these data indicate that the O(2)(-)-generating oxidase in DCs is cryptic, owing to the presence of a membrane-bound inhibitor of protein nature that prevents oxidase activation. The inhibition is relieved under specific conditions, including a prolonged contact of DCs with pro-inflammatory ligands from microbial origin, allowing a substantial production of O(2)(-), which may contribute to the response of DCs to a microbial exposure.
Elsen
Sylvie
S
Laboratoire de Biochimie et Biophysique des Systèmes Intégrés (UMR 5092 CNRS-CEA-UJF), Département Réponse et Dynamique Cellulaires, CEA-Grenoble, Grenoble Cedex, France.
Doussière
Jacques
J
Villiers
Christian L
CL
Faure
Mathias
M
Berthier
Rolande
R
Papaioannou
Anne
A
Grandvaux
Nathalie
N
Marche
Patrice N
PN
Vignais
Pierre V
PV
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002478:Cells, Cultured; D045303:Cytochromes b / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005960:Glucosides / Q000494:pharmacology; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D018836:Inflammation Mediators / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009252:NADPH Dehydrogenase / Q000378:metabolism; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000737:chemistry / Q000378:metabolism*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects; D010750:Phosphoproteins / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004791:Enzyme Inhibitors; D005960:Glucosides; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; C079789:neutrophil cytosol factor 67K; D013481:Superoxides; C018619:octyl-beta-D-glucoside; D006418:Heme; D045303:Cytochromes b; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C086986:CYBA protein, human; D009252:NADPH Dehydrogenase; D013755:Tetradecanoylphorbol Acetate