Nuclear factor-kappaB activates dual inhibition sites in the regulation of tumor necrosis factor-alpha-induced neutrophil apoptosis.
The objective of this study was to elucidate the role of the nuclear factor-kappaB (NF-kappaB) pathway in tumor necrosis factor-alpha (TNF-alpha)-induced neutrophil apoptosis. A single treatment with TNF-alpha produced significant caspase-3 activation in a time- and concentration-dependent manner, while no significant morphological change in neutrophils was observed. After pretreatment of neutrophils with cycloheximide or actinomycin D, TNF-alpha produced morphologically typical apoptosis in a time- and concentration-dependent manner. Similarly, following pretreatment of neutrophils with the specific NF-kappaB inhibitors, pyrrolidine dithiocarbamate or SN50, TNF-alpha also produced neutrophil apoptosis (assessed morphologically). Caspase-3 activation by TNF-alpha was significantly enhanced by pretreatment with both cycloheximide and pyrrolidine dithiocarbamate. TNF-alpha-induced a rapid phosphorylation and degradation of IkappaB-alpha in neutrophils. Furthermore, TNF-alpha increased NF-kappaB DNA binding, which was abolished by pretreatment with pyrrolidine dithiocarbamate. These results indicate that the NF-kappaB pathway is crucial for neutrophil survival against TNF-alpha cell toxicity. Furthermore, it is proposed that NF-kappaB-induced proteins act on dual inhibitory sites, both upstream and downstream of caspase-3, to protect against apoptosis.
Niwa
M
M
Department of Pharmacology, Gifu University School of Medicine, 40-Tsukasamachi, Gifu 500-8705, Japan. mniwa@cc.gifu-u.ac.jp
Hara
A
A
Kanamori
Y
Y
Hatakeyama
D
D
Saio
M
M
Takami
T
T
Matsuno
H
H
Kozawa
O
O
Uematsu
T
T
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000187:drug effects* / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D016328:NF-kappa B / Q000187:drug effects* / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012313:RNA / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D016328:NF-kappa B; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D014409:Tumor Necrosis Factor-alpha; D012313:RNA; D004247:DNA; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases