Fluoride-mediated activation of the respiratory burst in electropermeabilized neutrophils.
Electropermeabilization creates small pores in the plasma membrane allowing the introduction of low-molecular-weight modulatory components, such as ions and nucleotides, into the cytosol. The present study investigates fluoride-mediated stimulation of the signal transduction pathway that activates the respiratory burst in electropermeabilized neutrophils. In marked contrast to intact (i.e., non-electropermeabilized) neutrophils, cells permeabilized by this technique demonstrated an immediate and potent stimulation of the superoxide (O2-)-generating NADPH oxidase in response to the addition of fluoride. Furthermore, permeabilization of neutrophils in the presence of exogenously added ATP enhanced the rate of F(-)-mediated O2- production. Fluoride-stimulated O2- production in electropermeabilized neutrophils was antagonized by GDP beta S and dependent upon the presence of Mg2+ in the medium, but was insensitive to pertussis toxin treatment, consistent with the hypothesis that fluoride activates a G protein, probably Gp, by interacting with the nucleotide-binding site on the G alpha subunit. In addition, electropermeabilized neutrophil O2- release triggered by F- was blocked by staurosporine and H-7, indicating that this pathway proceeds largely through protein kinase C activation. However, nucleotide-enhanced O2- production was only partially blocked by these inhibitors, suggesting that under such conditions ATP either competes with the inhibitor-protein kinase interaction or affects the signaling pathway(s) in such a way that protein kinase C may no longer be necessary for the activation of NADPH oxidase.
Hartfield
P J
PJ
Department of Anatomy, Ohio State University, Columbus 43210.
Robinson
J M
JM
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002463:Cell Membrane Permeability; D005459:Fluorides / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000378:metabolism; D006168:Guinea Pigs; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007546:Isoquinolines / Q000494:pharmacology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D015398:Signal Transduction; D019311:Staurosporine
D000470:Alkaloids; D007546:Isoquinolines; D010879:Piperazines; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D019311:Staurosporine; D005459:Fluorides; D010100:Oxygen