p38 MAP kinase activation by Clostridium difficile toxin A mediates monocyte necrosis, IL-8 production, and enteritis.
p38 MAP kinase activation by Clostridium difficile toxin A mediates monocyte necrosis, IL-8 production, and enteritis.
复制标题
DOI：
10.1172/jci7545
复制
发表时间：
2000-04
期刊：
影响因子：
--
通讯作者：
M. Warny;A. C. Keates;S. Keates;I. Castagliuolo;Jeff Zacks;Samer Aboudola;A. Qamar;C. Pothoulakis;J. Lamont;C. Kelly
中科院分区：
文献类型：
--
作者：
M. Warny;A. C. Keates;S. Keates;I. Castagliuolo;Jeff Zacks;Samer Aboudola;A. Qamar;C. Pothoulakis;J. Lamont;C. Kelly
艰难梭菌毒素A引起急性中性粒细胞浸润和肠粘膜损伤。在培养的细胞中，毒素 A 通过单糖基化使 Rho 蛋白失活。在单核细胞中，毒素 A 通过未知机制诱导 IL-8 产生和坏死。我们研究了丝裂原激活蛋白（MAP）激酶在这些事件中的作用。在 THP-1 单核细胞中，毒素 A 在 1 至 2 分钟内激活 3 个主要 MAP 激酶级联。 p38 的激活是持续的，而细胞外信号调节激酶和 c-Jun NH(2) 末端激酶的刺激是短暂的。 15 分钟后 Rho 糖基化变得明显。 MEK 抑制剂 PD98059 可将 IL-8 基因表达降低 70%，p38 抑制剂 SB203580 或 p38 激活激酶 MKK3 和 MKK6 显性失活突变体的过度表达可消除 IL-8 基因表达。 SB203580 还可以阻断由毒素 A 引起的单核细胞坏死和 IL-1β 释放，但不能阻断由其他毒素引起的单核细胞坏死和 IL-1β 释放。最后，在小鼠回肠中，SB203580 阻止了毒素 A 诱导的中性粒细胞募集 92% 和绒毛破坏 90%。因此，在暴露于毒素 A 的单核细胞中，MAP 激酶激活似乎先于 Rho 糖基化，并且是 IL-8 转录和细胞坏死所必需的。 p38 MAP 激酶还介导毒素 A 诱导的肠道炎症和粘膜损伤。
Clostridium difficile toxin A causes acute neutrophil infiltration and intestinal mucosal injury. In cultured cells, toxin A inactivates Rho proteins by monoglucosylation. In monocytes, toxin A induces IL-8 production and necrosis by unknown mechanisms. We investigated the role of mitogen-activated protein (MAP) kinases in these events. In THP-1 monocytic cells, toxin A activated the 3 main MAP kinase cascades within 1 to 2 minutes. Activation of p38 was sustained, whereas stimulation of extracellular signal-regulated kinases and c-Jun NH(2)-terminal kinase was transient. Rho glucosylation became evident after 15 minutes. IL-8 gene expression was reduced by 70% by the MEK inhibitor PD98059 and abrogated by the p38 inhibitor SB203580 or by overexpression of dominant-negative mutants of the p38-activating kinases MKK3 and MKK6. SB203580 also blocked monocyte necrosis and IL-1beta release caused by toxin A but not by other toxins. Finally, in mouse ileum, SB203580 prevented toxin A-induced neutrophil recruitment by 92% and villous destruction by 90%. Thus, in monocytes exposed to toxin A, MAP kinase activation appears to precede Rho glucosylation and is required for IL-8 transcription and cell necrosis. p38 MAP kinase also mediates intestinal inflammation and mucosal damage induced by toxin A.