Endotoxin priming of neutrophils requires NADPH oxidase-generated oxidants and is regulated by the anion transporter ClC-3.
Several soluble mediators, including endotoxin, prime neutrophils for an enhanced respiratory burst in response to subsequent stimulation. Priming of neutrophils occurs in vitro, and primed neutrophils are found in vivo. We previously localized the anion transporter ClC-3 to polymorphonuclear leukocytes (PMN) secretory vesicles and demonstrated that it is required for normal NADPH oxidase activation in response to both particulate and soluble stimuli. We now explore the contribution of the NADPH oxidase and ClC-3 to endotoxin-mediated priming. Lipooligosaccharide (LOS) from Neisseria meningitidis enhances the respiratory burst in response to formyl-Met-Leu-Phe, an effect that was impaired in PMNs lacking functional ClC-3 and under anaerobic conditions. Mobilization of receptors to the cell surface and phosphorylation of p38 MAPK by LOS were both impaired in PMN with the NADPH oxidase chemically inhibited or genetically absent and in cells lacking functional ClC-3. Furthermore, inhibition of the NADPH oxidase or ClC-3 in otherwise unstimulated cells elicited a phenotype similar to that seen after endotoxin priming, suggesting that basal oxidant production helps to maintain cellular quiescence. In summary, NADPH oxidase activation was required for LOS-mediated priming, but basal oxidants kept unstimulated cells from becoming primed. ClC-3 contributes to both of these processes.
Moreland
Jessica G
JG
Division of Critical Care, Department of Pediatrics, The Inflammation Program, University of Iowa and Veterans Affairs Medical Center, Iowa City, IA 52242, USA. jessica-moreland@uiowa.edu
Davis
A Paige
AP
Matsuda
James J
JJ
Hook
Jessica S
JS
Bailey
Gail
G
Nauseef
William M
WM
Lamb
Fred S
FS
D000693:Anaerobiosis; D000818:Animals; D002460:Cell Line; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008070:Lipopolysaccharides / Q000737:chemistry / Q000494:pharmacology; D051379:Mice; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism*; D009345:Neisseria meningitidis / Q000737:chemistry; D018375:Neutrophil Activation / Q000187:drug effects / Q000235:genetics; D009504:Neutrophils / Q000166:cytology / Q000201:enzymology*; D010084:Oxidation-Reduction / Q000187:drug effects; D016897:Respiratory Burst / Q000187:drug effects / Q000235:genetics; D022142:Secretory Vesicles / Q000201:enzymology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D018118:Chloride Channels; C115376:ClC-3 channel; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; D048051:p38 Mitogen-Activated Protein Kinases