Phorbol myristate acetate induces neutrophil death through activation of p38 mitogen-activated protein kinase that requires endogenous reactive oxygen species other than HOCl.
Stimulation of normal mouse neutrophils with phorbol 12-myristate 13-acetate resulted in an acceleration of chromatin condensation and phosphatidylserine externalization that was not associated with caspase-3 activation. Caspase-independent death was completely inhibited by GF109203X and SB202190, specific inhibitors for protein kinase C and p38 mitogen-activated protein kinase respectively. Activation of p38 mitogen-activated protein kinase was completely suppressed by GF109203X, indicating that this enzyme is regulated by protein kinase C. On the other hand, cell death was abolished in NADPH oxidase-deficient neutrophils lacking superoxide production. Of note, p38 mitogen-activated protein kinase was activated by phorbol 12-myristate 13-acetate in normal and myeloperoxidase-deficient neutrophils lacking production of HOCl, whereas no activation was observed in NADPH oxidase-deficient neutrophils. These results strongly suggest that activation of p38 mitogen-activated protein kinase is regulated by endogenously generated superoxide or its metabolites other than HOCl, a critical regulator of inducer-stimulated death of neutrophils.
Saito
Takao
T
Kihara Institute for Biological Research, Yokohama City University, Japan.
Takahashi
Hajime
H
Doken
Hideo
H
Koyama
Hideki
H
Aratani
Yasuaki
Y
D000818:Animals; D016923:Cell Death; D004789:Enzyme Activation; D006997:Hypochlorous Acid; D051379:Mice; D008810:Mice, Inbred C57BL; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects*; D009195:Peroxidase / Q000172:deficiency; D011493:Protein Kinase C / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D017382:Reactive Oxygen Species; D006997:Hypochlorous Acid; D009195:Peroxidase; D019255:NADPH Oxidases; D011493:Protein Kinase C; D048051:p38 Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate