IL-10 protects mouse intestinal epithelial cells from Fas-induced apoptosis via modulating Fas expression and altering caspase-8 and FLIP expression
IL-10 protects mouse intestinal epithelial cells from Fas-induced apoptosis via modulating Fas expression and altering caspase-8 and FLIP expression
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DOI：
10.1152/ajpgi.00438.2005
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发表时间：
2006-11-01
影响因子：
4.5
通讯作者：
Croitoru, Kenneth
中科院分区：
文献类型：
--
作者：
Bharhani, Mantej S.;Borojevic, Rajka;Croitoru, Kenneth
我们先前已经证明，在T细胞介导的肠病的活体模型中，Fas/Fas配体的缺失显著减少了组织损伤和肠上皮细胞(IEC)的凋亡。这种肠病在IL-10缺乏的小鼠中更为严重，这与血清中干扰素-γ和肿瘤坏死因子-α水平的升高以及IECS上Fas表达的增加有关。在本研究中，我们研究了IL-10直接影响Fas表达和Fas诱导的IEC凋亡的可能性。小鼠肠上皮细胞株MODE-K和IEC4.1分别与干扰素-γ、肿瘤坏死因子-α或抗Fas单抗(MAb)共同培养，同时加入或不加入IL-10。FACScan藻红蛋白-抗Fas单抗染色和Annexin V染色分别检测Fas表达和细胞凋亡率。联合应用干扰素-γ和肿瘤坏死因子-α可诱导显著的细胞凋亡。除非用干扰素-γ和肿瘤坏死因子-α对细胞进行预处理，否则抗Fas单抗不能诱导细胞大量的凋亡。这些IEC结构性地表达低水平的Fas，预先与干扰素-γ和肿瘤坏死因子-α共同孵育后，Fas的表达显著增加。细胞因子或细胞因子联合抗Fas单抗处理可增加细胞凋亡，这与Fas相关死亡区域IL-1转换酶样抑制蛋白(FliP)水平降低、caspase-8活性升高以及随后caspase-3活性升高有关。IL-10可抑制细胞因子和抗Fas单抗诱导的细胞凋亡，这与细胞因子诱导的Fas表达减少、FliP增加、caspase-8和caspase-3活性降低有关。综上所述，IL-10调节细胞因子诱导IEC细胞Fas表达，并调节IEC对肿瘤坏死因子-α、干扰素-γ和Fas介导的细胞凋亡的敏感性。这些发现表明，IL-10直接调节IEC对T细胞介导的凋亡信号的反应。
We have previously shown that the absence of Fas/Fas ligand significantly reduced tissue damage and intestinal epithelial cell (IEC) apoptosis in an in vivo model of T cell-mediated enteropathy. This enteropathy was more severe in IL-10-deficient mice, and this was associated with increased serum levels of IFN-gamma and TNF-alpha and an increase in Fas expression on IECs. In this study, we investigated the potential of IL-10 to directly influence Fas expression and Fas-induced IEC apoptosis. Mouse intestinal epithelial cell lines MODE-K and IEC4.1 were cultured with IFN-gamma, TNF-alpha, or anti-Fas monoclonal antibody (mAb) in the presence or absence of IL-10. Fas expression and apoptosis were determined by FACScan analysis of phycoerythrin-anti-Fas mAb staining and annexin V staining, respectively. Treatment with a combination of IFN-gamma and TNF-alpha induced significant apoptosis. Anti-Fas mAb alone did not induce much apoptosis unless cells were pretreated with IFN-gamma and TNF-alpha. These IECs constitutively expressed low levels of Fas, which significantly increased by preincubation of the cells with IFN-gamma and TNF-alpha. Treatment with cytokine or cytokine plus anti-Fas mAb increased apoptosis, which correlated with a decreased Fas-associated death domain IL-1-converting enzyme-like inhibitory protein (FLIP) level, increased caspase-8 activity, and subsequently increased caspase-3 activity. IL-10 diminished both cytokine- and anti-Fas mAb-induced apoptosis, and this was correlated with decreased cytokine-induced Fas expression, increased FLIP, and decreased caspase-8 and caspase-3 activity. In conclusion, IL-10 modulated cytokine induction of Fas expression on IEC cell lines and regulated IEC susceptibility to TNF-alpha, IFN-gamma, and Fas-mediated apoptosis. These findings suggest that IL-10 directly modulates IEC responses to T cell-mediated apoptotic signals.