A time-course study on superoxide generation and protein kinase C activation in human neutrophils.
The time course of superoxide generation and membrane association of protein kinase C was studied in human neutrophils stimulated by PMA, FMLP, ionomycin and A23187. The initiation of superoxide generation in PMA; ionomycin- and A23187-stimulated neutrophils was characterized by a lag period of at least 30 s in contrast to a lag period of 10-15 s in FMLP-stimulated cells. The time course of membrane association of protein kinase C in PMA-stimulated neutrophils was highly dependent upon the PMA concentration used for stimulation. However, membrane association of protein kinase C preceded superoxide generation in cells stimulated by 10-300 ng/ml PMA. FMLP, ionomycin and A23187 induced membrane association of protein kinase C in a few seconds and always before superoxide generation. It is concluded that membrane association of protein kinase C in PMA-, FMLP-, ionomycin- and A23187-stimulated neutrophils precedes superoxide generation, and thereby may be part of the mechanism initiating NADPH-oxidase activity. A simple correlation between the two parameters could not be proven, indicating that also other activation mechanisms are decisive in the activation of NADPH-oxidase.
Christiansen
N O
NO
Department of Medicine and Infectious Diseases, Marselisborg Hospital, University of Aarhus, Denmark.
D000001:Calcimycin / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D004987:Ethers / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D015759:Ionomycin; D007700:Kinetics; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D011493:Protein Kinase C / Q000097:blood*; D013481:Superoxides / Q000097:blood*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
D004987:Ethers; D013481:Superoxides; D000001:Calcimycin; D015759:Ionomycin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate