Respiratory burst oscillations in human neutrophils and their correlation with fluctuations in apparent cell shape.
Neutrophils pretreated with phorbol 12-myristate 13-acetate (1-10 nM) and stimulated with low concentrations of chemotactic agonists (1-10nM) exhibited a marked increase in respiratory burst activity that was characterized by regular oscillations. These were accompanied by parallel oscillations in turbidity having the same phase and period. Four different agonists, f-Met-Leu-Phe, complement fragment C5a, platelet-activating factor, and leukotriene B4, induced virtually identical oscillations, with mean periods of 7.9 +/- 0.6 s (respiratory burst) and 7.9 +/- 0.8 s (turbidity) at 37 degrees C. No burst oscillations were observed at high agonist concentrations (50-100 nM) unless the fungal metabolite 17-hydroxywortmannin was added prior to stimulation. In the absence of phorbol 12-myristate 13-acetate, the respiratory burst activity was inhibited by 17-hydroxywortmannin, the protein kinase C inhibitor staurosporine, and calcium depletion, while agonist-dependent turbidity changes including the oscillations were unaffected. Turbidity changes reflect corresponding changes in cell size and/or shape, suggesting that cyclic alterations in morphology such as lamellipod extension and retraction physically affect the catalytic efficiency of the membrane-bound burst enzyme NADPH-oxidase. The oscillations appear to be controlled via receptor-dependent activation mechanisms which do not involve PKC activation or the rise in internal calcium presumably derived from phospholipase C activation.
Theodor Kocher Institute, University of Bern, Switzerland.
M P
MP
Wymann
P
P
Kernen
D A
DA
Deranleau
M
M
Baggiolini
D000730:Androstadienes / Q000494:pharmacology; D001572:Benzofurans; D002118:Calcium / Q000097:blood; D003600:Cytosol / Q000378:metabolism; D016257:Fura-2; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood; D066298:In Vitro Techniques; D007700:Kinetics; D008163:Luminescent Measurements; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*; D013696:Temperature; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000730:Androstadienes; D001572:Benzofurans; C053480:17-hydroxywortmannin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D006861:Hydrogen Peroxide; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; D016257:Fura-2