Cellular differentiation causes a selective down-regulation of interleukin (IL)-1β-mediated NF-κB activation and IL-8 gene expression in intestinal epithelial cells
Cellular differentiation causes a selective down-regulation of interleukin (IL)-1β-mediated NF-κB activation and IL-8 gene expression in intestinal epithelial cells
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DOI：
10.1074/jbc.275.16.12207
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发表时间：
2000-04-21
影响因子：
4.8
通讯作者：
Jobin, C
中科院分区：
文献类型：
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作者：
Böcker, U;Schottelius, A;Jobin, C
白细胞介素（IL）-1 β通过各种衔接蛋白和激酶发出信号，这些蛋白和激酶导致许多下游靶标的激活，包括转录因子，包括NF-κ B。在这项研究中，我们分析和表征了肠上皮细胞分化对IL-1 β介导的NF-κ B活化和IL-8基因表达的影响。我们报告说，IL-8 mRNA的积累和蛋白质分泌下调IL-1 β和脂多糖刺激分化的HT-29细胞（HT-29/MTX，其中MTX是甲氨蝶呤）与未分化的细胞（HT-29/p）相比，而没有发现肿瘤坏死因子（TNF）-α或佛波醇肉豆蔻酸酯刺激后的差异效应。交联和亲和结合研究表明，IL-1 β在HT-29/p和HT-29/MTX细胞中仅结合I型受体（IL-1 RI），而不结合IL-1 RII。IL-1 β介导的I κ B激酶和c-Jun N-末端激酶（JNK）活性在分化的HT-29细胞中均降低。相对于HT-29/p细胞，分化的HT-29细胞中的DNA结合活性在IL-1 β暴露后强烈降低，但在TNF-α刺激后不降低。在IL-1 β刺激的HT-29细胞中，近端IL-1信号分子IL-1受体相关激酶没有降解，与Caco-2细胞相反，在HT-29/MTX细胞中IL-1 β刺激后，TNF受体相关因子-6转染后，κ B-荧光素酶报告基因活性高16倍。我们的结论是，HT-29细胞的细胞分化选择性地损害IL-1 β信号通路，抑制NF-κ B和JNK活性，以响应IL-1 β。这种对IL-1 β的相对无反应性可能代表了分化的肠上皮细胞的重要调节机制。
Interleukin (IL)-1 beta signals through various adapter proteins and kinases that lead to activation of numerous downstream targets, including the transcription factors including NF-kappa B. In this study, we analyzed and characterized the effect of the differentiation of intestinal epithelial cells on IL-1 beta-mediated NF-kappa B activation and IL-8 gene expression. We report that IL-8 mRNA accumulation and protein secretion were down-regulated in IL-1 beta- and lipopolysaccharide-stimulated differentiated HT-29 cells (HT-29/MTX, where MTX is methotrexate) compared with undifferentiated cells (HT-29/p), whereas no differential effects were found following tumor necrosis factor (TNF)-alpha or phorbol myristate acetate stimulation. Cross-linking and affinity binding studies reveal that IL-1 beta exclusively binds the type I receptor (IL-1RI) and not IL-1RII in both HT-29/p and HT-29/MTX cells. IL-1 beta-mediated I kappa B kinase and c-Jun N-terminal kinase (JNK) activity were both diminished in differentiated HT-29 cells. DNA binding activity in differentiated HT-29 cells relative to HT-29/p cells was strongly reduced following IL-1 beta exposure but not after TNF-alpha stimulation. The proximal IL-1 signaling molecule IL-1 receptor-associated kinase was not degraded in IL-1 beta-stimulated HT-29 cells, in contrast to Caco-2 cells, kappa B-luciferase reporter gene activity was 16-fold higher following TNF receptor-associated factor-6 transfection after IL-1 beta stimulation in HT-29/MTX cells. We conclude that cellular differentiation of HT-29 cells selectively impairs the IL-1 beta signaling pathway inhibiting both NF-kappa B and JNK activity in response to IL-1 beta. This relative unresponsiveness to IL-1 beta may represent an important regulatory mechanism of differentiated intestinal epithelial cells.