NOD2 transgenic mice exhibit enhanced MDP-mediated down-regulation of TLR2 responses and resistance to colitis induction
NOD2 transgenic mice exhibit enhanced MDP-mediated down-regulation of TLR2 responses and resistance to colitis induction
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DOI：
10.1053/j.gastro.2007.07.025
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发表时间：
2007-11-01
期刊：
影响因子：
29.4
通讯作者：
Kitani, Atsushi
中科院分区：
文献类型：
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作者：
Yang, Zhiqiong;Fuss, Ivan J.;Kitani, Atsushi
背景与目的：编码NOD2的CARD15基因突变是克罗恩病的易感因素。我们使用过表达NOD2的小鼠来探索这种易感性的机制。方法：检测转染NOD2转基因或转染表达野生型和突变型NOD2构建的质粒小鼠的细胞和分子反应。在最初的研究中，我们发现，与对照组相比，NOD2转基因小鼠的脾细胞对肽聚糖（PGN）的白介素(IL)-12p70反应降低，PGN是一种含有muramyl二肽的TLR2配体，但不含其他TLR配体；相比之下，IL-12对PAM(3)CSK(4)（一种不含muramyl二肽的TLR2配体）的反应是正常的。同样，与对照组相比，转基因小鼠对腹腔注射PGN的IL-12p40反应显著降低，而对脂多糖则没有反应。在进一步的研究中，我们通过电泳迁移率转移实验发现，转基因小鼠的pgnn刺激细胞显示出核因子kappa b的活化降低。最后，在一系列关于NOD2对诱导性结肠炎易感性影响的研究中，我们发现(1)转基因小鼠对诱导PGN型结肠炎具有高度抗性，对诱导三硝基苯磺酸（TNBS）结肠炎具有部分抗性；(2)给予表达野生型NOD2基因的质粒的小鼠对TNBS结肠炎具有完全抗性，而给予表达带有克罗恩病移位突变的NOD2基因的质粒的小鼠对TNBS结肠炎只有轻微抗性。结论：这些数据提供了新的证据，表明NOD2突变通过引起过度的TLR2细胞因子反应而导致炎症性肠病。
Background & Aims: Mutations in the CARD15 gene encoding NOD2 are susceptibility factors in Crohn's disease. We explored the mechanism of this susceptibility using mice that over express NOD2. Methods: Cellular and molecular responses of mice bearing an NOD2 transgene or administered plasmids that express wild-type and mutated NOD2 constructs were examined Results; In initial studies, we showed that splenocytes from NOD2 transgenic mice as compared with littermate controls exhibit decreased interleukin (IL)-12p70 responses to peptidoglycan (PGN), a TLR2 ligand that contains muramyl dipeptide, but not other TLR ligands; in contrast, IL-12 responses to PAM(3)CSK(4), a TLR2 ligand that does not contain muramyl dipeptide, were normal. Similarly, transgenic mice as compared with controls exhibited greatly decreased IL-12p40 responses to intraperitoneal administration of PGN but not to lipopolysaccharide. In further studies, we showed using electrophoretic mobility shift assay that PGN-stimulated cells from transgenic mice exhibited decreased activation of nuclear factor kappa B. Finally, in a series of studies on the effect of the NOD2 on susceptibility to induced colitis, we found that (1) transgenic mice were highly resistant to induction of PGN colitis and partially resistant to induction of trinitrobenzene sulfonic acid (TNBS) colitis and (2) mice administered a plasmid expressing a wild-type NOD2 gene were completely resistant to TNBS colitis whereas mice administered a plasmid expressing an NOD2 gene with the Crohn's disease frameshift mutation were only slightly resistant to TNBS colitis. Conclusions: These data offer new evidence that NOD2 mutations contribute to inflammatory bowel disease by causing excessive TLR2 cytokine responses.