Toll-Like Receptor 2 Regulates Intestinal Inflammation by Controlling Integrity of the Enteric Nervous System
Toll-Like Receptor 2 Regulates Intestinal Inflammation by Controlling Integrity of the Enteric Nervous System
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DOI：
10.1053/j.gastro.2013.08.047
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发表时间：
2013-12-01
期刊：
影响因子：
29.4
通讯作者：
Castagliuolo, Ignazio
中科院分区：
文献类型：
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作者：
Brun, Paola;Giron, Maria Cecilia;Castagliuolo, Ignazio
背景与目的：在肠道中，Toll样受体2（TLR 2）介导对病原体的免疫应答并调节上皮屏障功能; TLR 2的多态性与炎症性肠病表型相关。我们评估了TLR 2信号对小鼠肠神经系统（ENS）的影响。方法：通过免疫荧光、细胞荧光分析、免疫沉淀和免疫印迹分析确定小鼠回肠神经肌肉层中TLR 2的分布和功能。我们使用免疫荧光、免疫印迹和胃肠动力测定评估了Tlr 2（-/-）小鼠和肠道微生物群耗尽的野生型Tlr 2小鼠（野生型小鼠）中ENS的形态和功能。胶质细胞源性神经营养因子（GDNF）的水平和信号转导的定量逆转录聚合酶链反应，免疫组化和免疫沉淀分析。在终止GDNF给药后，通过向Tlr 2（-/-）小鼠给药葡聚糖硫酸钠或2，4二硝基苯磺酸诱导结肠炎。结果：TLR 2表达于肠神经元、神经胶质细胞和肠壁平滑肌细胞。Tlr 2（-/-）小鼠ENS结构和神经化学特征发生改变，肠运动障碍，粘膜分泌异常，平滑肌细胞中GDNF水平降低，通过Ret-GFR α 1的信号传导受损。ENS的结构和功能异常完全纠正GDNF的管理Tlr 2（-/-）小鼠。耗尽肠道微生物群的野生型小鼠具有ENS缺陷和GDNF缺陷，类似于Tlr 2（-/-）小鼠;这些缺陷通过施用TLR 2激动剂而部分恢复。在给予葡聚糖硫酸钠或2，4二硝基苯磺酸后，Tlr 2（-/-）小鼠比野生型小鼠发生更严重的结肠炎;如果在给予葡聚糖硫酸钠或2，4二硝基苯磺酸之前给予Tlr 2（-/-）小鼠GDNF，结肠炎不会更严重。结论：在小鼠中，TLR 2信号通过控制ENS结构和神经化学编码沿着肠道神经肌肉功能来调节肠道炎症。这些发现提供了ENS中TLR 2信号传导缺陷如何影响人类炎症性肠病表型的信息。
BACKGROUND & AIMS: In the intestines, Toll-like receptor 2 (TLR2) mediates immune responses to pathogens and regulates epithelial barrier function; polymorphisms in TLR2 have been associated with inflammatory bowel disease phenotype. We assessed the effects of TLR2 signaling on the enteric nervous system (ENS) in mice. METHODS: TLR2 distribution and function in the ileal neuromuscular layer of mice were determined by immunofluorescence, cytofluorimetric analysis, immunoprecipitation, and immunoblot analyses. We assessed morphology and function of the ENS in Tlr2(-/-) mice and in mice with wild-type Tlr2 (wild-type mice) depleted of intestinal microbiota, using immunofluorescence, immunoblot, and gastrointestinal motility assays. Levels and signaling of glial cell line-derived neurotrophic factor (GDNF) were determined using quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry, and immunoprecipitation analyses. Colitis was induced by administration of dextran sulfate sodium or 2,4 dinitrobenzensulfonic acid to Tlr2(-/-) mice after termination of GDNF administration. RESULTS: TLR2 was expressed in enteric neurons, glia, and smooth muscle cells of the intestinal wall. Tlr2(-/-) mice had alterations in ENS architecture and neurochemical profile, intestinal dysmotility, abnormal mucosal secretion, reduced levels of GDNF in smooth muscle cells, and impaired signaling via Ret-GFR alpha 1. ENS structural and functional anomalies were completely corrected by administration of GDNF to Tlr2(-/-) mice. Wild-type mice depleted of intestinal microbiota had ENS defects and GDNF deficiency, similar to Tlr2(-/-) mice; these defects were partially restored by administration of a TLR2 agonist. Tlr2(-/-) mice developed more severe colitis than wild-type mice after administration of dextran sulfate sodium or 2,4 dinitrobenzensulfonic acid; colitis was not more severe if Tlr2(-/-) mice were given GDNF before dextran sulfate sodium or 2,4 dinitrobenzensulfonic acid. CONCLUSIONS: In mice, TLR2 signaling regulates intestinal inflammation by controlling ENS structure and neurochemical coding, along with intestinal neuromuscular function. These findings provide information as to how defective TLR2 signaling in the ENS affects inflammatory bowel disease phenotype in humans.