Niwa M, Hara A, Kanamori Y, Hatakeyama D, Saio M, Takami T, Matsuno H, Kozawa O, Uematsu T
Department of Pharmacology, Gifu University School of Medicine, 40-Tsukasamachi, Gifu 500-8705, Japan.
Eur J Pharmacol. 2000 Nov 3;407(3):211-9. doi: 10.1016/s0014-2999(00)00735-4.
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.
本研究的目的是阐明核因子-κB（NF-κB）信号通路在肿瘤坏死因子-α（TNF-α）诱导的中性粒细胞凋亡中的作用。单次给予TNF-α可呈时间和浓度依赖性地显著激活半胱天冬酶-3（caspase-3），而中性粒细胞未观察到明显的形态学变化。用放线菌酮或放线菌素D预处理中性粒细胞后，TNF-α可呈时间和浓度依赖性地诱导出形态学上典型的凋亡。同样，用特异性NF-κB抑制剂吡咯烷二硫代氨基甲酸盐或SN50预处理中性粒细胞后，TNF-α也可诱导中性粒细胞凋亡（通过形态学评估）。用放线菌酮和吡咯烷二硫代氨基甲酸盐预处理均显著增强了TNF-α对caspase-3的激活作用。TNF-α可诱导中性粒细胞中IκB-α快速磷酸化和降解。此外，TNF-α可增加NF-κB与DNA的结合，而吡咯烷二硫代氨基甲酸盐预处理可消除这种结合。这些结果表明，NF-κB信号通路对于中性粒细胞抵抗TNF-α细胞毒性的存活至关重要。此外，有人提出，NF-κB诱导的蛋白作用于caspase-3上下游的双重抑制位点，以防止细胞凋亡。
