Interferon-γ augments CARD4/NOD1 gene and protein expression through interferon regulatory factor-1 in intestinal epithelial cells
Interferon-γ augments CARD4/NOD1 gene and protein expression through interferon regulatory factor-1 in intestinal epithelial cells
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DOI：
10.1074/jbc.m304355200
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发表时间：
2003-08-29
影响因子：
4.8
通讯作者：
Podolsky, DK
中科院分区：
文献类型：
--
作者：
Hisamatsu, T;Suzuki, M;Podolsky, DK
虽然肠上皮细胞似乎对正常肠植物群功能性低反应，但人肠上皮细胞可对肠侵入性细菌产生反应并诱导炎症反应。这种最初的炎症反应导致多形核白细胞在体外和体内募集到受影响的部位。CARD 4/NOD 1是哺乳动物细胞中潜在的肽聚糖胞浆受体，类似于植物的病原体抗性蛋白。在这种情况下，CARD 4/NOD 1是肠上皮细胞中的细胞内细菌或肽聚糖的识别蛋白的候选者。在这项研究中，我们证明CARD 4/NOD 1是组成型表达的肠上皮细胞系和分离的原代肠上皮细胞。干扰素-γ（IFN γ）是肠粘膜炎症中的有效促炎细胞因子，其以时间和剂量依赖性方式激活CARD 4/NOD 1 mRNA转录，并导致SW 480细胞中CARD 4/NOD 1蛋白的增加。CARD 4/NOD 1启动子分析表明干扰素调节因子-1（IRF-1）结合基序（-791至-782）对于IFN γ的作用是必需的。用IFN γ处理的SW 480细胞的核提取物显示与该IRF-1结合基序对应的寡核苷酸的特异性结合，其在电泳迁移率变动测定中被抗IRF-1抗体超移位。在IRF-1表达质粒与CARD 4/NOD 1启动子的共转染试验中，IRF-1蛋白的过表达激活CARD 4/NOD 1启动子，但不激活IRF-1结合位点的缺失突变体。这些研究表明，Th 1细胞因子IFN γ激活CARD 4/NOD 1转录并调节肠粘膜炎症条件下的先天免疫机制。
Although intestinal epithelial cells appear to be functionally hyporesponsive to normal intestinal flora, human intestinal epithelial cells can respond to enteroinvasive bacteria and induce an inflammatory response. This initial inflammatory response leads to the recruitment of polymorphonuclear leukocytes to the affected site in vitro and in vivo. CARD4/NOD1 is a potential cytosolic receptor for peptidoglycan in mammalian cells that resembles pathogen-resistant proteins of plants. In this context, CARD4/NOD1 is a candidate for a recognition protein of intracellular bacteria or peptidoglycan in intestinal epithelial cells. In this study, we demonstrate that CARD4/NOD1 is constitutively expressed in intestinal epithelial cell lines and isolated primary intestinal epithelial cells. Interferon-gamma (IFNgamma), which is a potent pro-inflammatory cytokine in intestinal mucosal inflammation, activates CARD4/NOD1 mRNA transcription in a time- and dose-dependent manner and results in augmentation of CARD4/NOD1 protein in SW480 cells. Promoter analysis of CARD4/NOD1 indicates that interferon regulatory factor-1 (IRF-1) binding motif (-791 to -782) is essential for the effect of IFNgamma. Nuclear extracts from SW480 cells treated with IFNgamma show specific binding of oligonucleotides corresponding to this IRF-1-binding motif, which was supershifted by anti-IRF-1 antibody in electrophoretic mobility shift assay. Overexpression of IRF-1 protein activates the CARD4/NOD1 promoter but not the deletion mutant of the IRF-1-binding site in a co-transfection assay of IRF-1 expression plasmid with CARD4/NOD1 promoter. These studies suggest that the Th1 cytokine, IFNgamma, activates CARD4/NOD1 transcription and regulate innate immune mechanisms in the condition of intestinal mucosal inflammation.