Signal transduction mechanism involved in Clostridium perfringens alpha-toxin-induced superoxide anion generation in rabbit neutrophils
Signal transduction mechanism involved in Clostridium perfringens alpha-toxin-induced superoxide anion generation in rabbit neutrophils
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DOI：
10.1128/iai.74.5.2876-2886.2006
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发表时间：
2006-05-01
影响因子：
3.1
通讯作者：
Sakurai, J
中科院分区：
文献类型：
--
作者：
Oda, M;Ikari, S;Sakurai, J
梭菌：产气荚膜杆菌α-毒素通过在兔嗜中性粒细胞中产生1，2-二酰基甘油（DG）诱导超氧阴离子（O-2（-））的产生。然而，其产生机制仍然知之甚少。在这里，我们报告了一种新的机制，毒素诱导的生产O-2（-）在兔中性粒细胞。用毒素处理细胞导致约140 kDa蛋白质的酪氨酸磷酸化。该蛋白与抗TrkA（神经生长因子高亲和力受体）抗体反应并结合神经生长因子。抗TrkA抗体抑制O-2（-）的产生和毒素与蛋白的结合。毒素诱导3-磷酸肌醇依赖性蛋白激酶1（PDK 1）磷酸化。TrkA受体抑制剂K252 a和磷脂酰肌醇3-激酶（PI 3 K）抑制剂LY 294002可减少毒素诱导的O-2（-）产生和PDK 1磷酸化，但不能减少DG的形成。这些抑制剂抑制毒素诱导的蛋白激酶C θ（PKC θ）磷酸化。U 73122，一种磷脂酶C（PLC）抑制剂，和百日咳毒素抑制毒素诱导的O-2（-）的产生和DG的形成，但不磷酸化的PDK 1。这些观察结果表明，毒素通过激活内源性PLC和磷酸化PDK 1（通过TrkA受体信号传导途径）独立诱导DG的产生，这些事件协同激活PKC θ刺激O-2（-）增加。此外，我们还发现，在毒素诱导的O-2（-）生成过程中，丝裂原活化蛋白激酶相关的信号事件通过PKC θ的活化而参与其中。
Clostridium: perfringens alpha-toxin induces the generation of superoxide anion (O-2(-)) via production of 1,2-diacylglycerol (DG) in rabbit neutrophils. The mechanism of the generation, however, remains poorly understood. Here we report a novel mechanism for the toxin-induced production of O-2(-) in rabbit neutrophils. Treatment of the cells with the toxin resulted in tyrosine phosphorylation of a protein of about 140 kDa. The protein reacted with anti-TrkA (nerve growth factor high-affinity receptor) antibody and bound nerve growth factor. Anti-TrkA antibody inhibited the production of O-2(-) and binding of the toxin to the protein. The toxin induced phosphorylation of 3-phosphoinositide-dependent protein kinase 1 (PDK1). K252a, an inhibitor of TrkA receptor, and LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3K), reduced the toxin-induced production of O-2(-) and phosphorylation of PDK1, but not the formation of DG. These inhibitors inhibited the toxin-induced phosphorylation of protein kinase C theta (PKC theta). U73122, a phospholipase C (PLC) inhibitor, and pertussis toxin inhibited the toxin-induced generation of O-2(-) and formation of DG, but not the phosphorylation of PDK1. These observations show that the toxin independently induces production of DG through activation of endogenous PLC and phosphorylation of PDK1 via the TrkA receptor signaling pathway and that these events synergistically activate PKC theta in stimulating an increase in O-2(-). In addition, we show the participation of mitogen-activated protein kinase-associated signaling events via activation of PKC theta in the toxin-induced generation of O-2(-).