Activation of interleukin-1 receptor-associated kinase by gram-negative flagellin
Activation of interleukin-1 receptor-associated kinase by gram-negative flagellin
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DOI：
10.1128/iai.69.7.4424-4429.2001
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发表时间：
2001-07-01
影响因子：
3.1
通讯作者：
Mizel, SB
中科院分区：
文献类型：
--
作者：
Moors, MA;Li, LW;Mizel, SB
来自各种革兰氏阴性菌的鞭毛蛋白激活单核细胞以产生促炎细胞因子，我们已经分析了沙门氏菌鞭毛蛋白（FliC）激活鼠和人单核细胞/巨噬细胞样细胞系的途径，因为已知革兰氏阴性菌的主要免疫刺激组分脂多糖（LPS）通过Toll样受体4（TLR 4）发出信号，我们测试了FliC也通过TLR 4发出信号的可能性。当在中和性抗TLR 4单克隆抗体存在下用LPS刺激鼠HeNC 2细胞时，肿瘤坏死因子α（TNF-α）和一氧化氮（NO）的产生显著减少。相反，FliC介导的TNF-α和NO产生受抗TLR 4抗体的影响最小。此外，与LPS不同，FliC刺激TLR 4突变细胞系GG 2 EE中的TNF-α产生，表明TLR 4对于FliC介导的信号传导不是必需的。为了测试FliC通过另一种TLR进行信号传导的可能性，我们测量了FliC介导的白细胞介素-1（IL-1）受体相关激酶（IRAK）的活化，IRAK是IL-1 R/TLR信号传导中的中心组分。FliC在HeNC 2和GG 2 EE细胞以及人前单核细胞系THP-I中诱导IRAK活化，IRAK活化在HeNC 2细胞中快速，在用FliC处理5分钟后观察到最大活性。此外，FliC介导的IRAK活化表现出与TNF-α诱导所证明的相同的浓度依赖性。这些结果代表了通过纯化的细菌蛋白激活IRAK的第一个证明，并强烈表明与TLR 4不同的TLR参与了对FliC的巨噬细胞炎症反应。
Flagellin from various species of gram-negative bacteria activates monocytes to produce proinflammatory cytokines, We have analyzed the pathway by which Salmonella enteritidis flagellin (FliC) activates murine and human monocyte/macrophage-like cell lines, Since lipopolysaccharide (LPS), the principal immune stimulatory component of gram-negative bacteria, is known to signal through Toll-like receptor 4 (TLR4), we tested the possibility that FliC also signals via TLR4, When murine HeNC2 cells were stimulated with LPS in the presence of a neutralizing anti-TLR4 monoclonal antibody, tumor necrosis factor alpha (TNF-alpha) and nitric oxide (NO) production were markedly reduced. In contrast, FliC-mediated TNF-alpha and NO production were minimally affected by the anti-TLR4 antibody. Furthermore, FliC, unlike LPS, stimulated TNF-alpha production in the TLR4 mutant cell line, GG2EE, indicating that TLR4 is not essential for FliC-mediated signaling, To test the possibility that FliC signals via another TLR, we measured FliC-mediated activation of interleukin-1 (IL-1) receptor-associated kinase (IRAK), a central component in IL-1R/TLR signaling. FliC induced IRAK activation in HeNC2 and GG2EE cells as well as in the human promonocytic cell line THP-I, IRAK activation was rapid in HeNC2 cells, with maximal activity observed after 5 min of treatment with FliC, In addition, FliC-mediated IRAK activation exhibited the same concentration dependence as was demonstrated for the induction of TNF-alpha. These results represent the first demonstration of IRAK activation by a purified bacterial protein and strongly suggest that a TLR distinct from TLR4 is involved in the macrophage inflammatory response to FliC.