Chen Jie, Ng Chuen Pei, Tsang Lai Ling, Ho Lok Sze, Xu Peng Hui, Rowlands Dewi Kenneth, Gao Jie Ying, Chung Yiu Wa, Li Ting Yu, Chan Hsiao Chang
Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong.
Cell Biol Int. 2009 Mar;33(3):369-75. doi: 10.1016/j.cellbi.2009.01.004.
The intense innate immunological activities occurring at the enteric mucosal surface involve interactions between intestinal epithelial cells and immune cells. Our previous studies have indicated that Peyer's patch lymphocytes may modulate intestinal epithelial barrier and ion transport function in homeostasis and host defense via cell-cell contact as well as cytokine signaling. The present study was undertaken using the established co-culture system of Caco-2 epithelial cells with lymphocytes of Peyer's patch to investigate the expression of IL-8 and IL-6 cytokines and cytokine receptors in the co-culture system after challenge with Shigella F2a-12 lipopolysaccharide (LPS). The human colonic epithelial cell line Caco-2 was co-cultured with freshly isolated lymphocytes from the murine Peyer's patch either in the mixed or separated (isolated but permeable compartments) co-culture configuration, and was challenged with Shigella F2a-12 LPS for 8 h. The level of mRNA expressions of human interleukin-8 (hIL-8), human interleukin-8 receptor (hIL-8R), mouse interleukin-8 receptor (mIL-8R), mouse interleukin-6 (mIL-6), mouse interleukin-6 receptor (mIL-6R) and human interleukin-6 receptor (hIL-6R) was examined by semi-quantitative PCR. In both co-culture groups, hIL-8 expression of Caco-2 cells was decreased, and hIL-8R expression was increased compared to the Caco-2 alone group. Upon LPS challenge, hIL-8 expression from the Caco-2 cells of both co-culture groups was higher than in the Caco-2 control group. The increased hIL-8 expression of Caco-2 cells in the separated co-culture group is correlated with a decreased hIL-8R expression and an increased mIL-8R expression. In the mixed co-culture group, the increased expression of hIL-8 was associated with the upregulated hIL-8R expression on Caco-2 cells and downregulated mIL-8R on murine Peyer's patch lymphocytes (PPL). mIL-6 expression from mouse PPL was also upregulated by LPS in mixed co-culture. However, upon the treatment with LPS, hIL-6R expression of Caco-2 cells was decreased in the mixed co-culture, but increased in separated co-culture. The data suggest that release of hIL-8 from epithelial cells may act on lymphocytes through a paracrine pathway, but it may also act on the epithelial cells themselves via an autocrine pathway. The data also suggest that the release of mIL-6 from Peyer's patch lymphocytes affects epithelial cells in a paracrine fashion.
发生在肠道黏膜表面的强烈先天性免疫活动涉及肠道上皮细胞和免疫细胞之间的相互作用。我们之前的研究表明，派尔集合淋巴结淋巴细胞可能通过细胞间接触以及细胞因子信号传导，在稳态和宿主防御中调节肠道上皮屏障和离子转运功能。本研究采用已建立的Caco-2上皮细胞与派尔集合淋巴结淋巴细胞的共培养系统，以研究用福氏志贺菌F2a-12脂多糖（LPS）刺激后共培养系统中白细胞介素-8（IL-8）和白细胞介素-6（IL-6）细胞因子及其受体的表达。将人结肠上皮细胞系Caco-2与从小鼠派尔集合淋巴结新鲜分离的淋巴细胞以混合或分离（隔离但可渗透的隔室）共培养配置进行共培养，并用福氏志贺菌F2a-12 LPS刺激8小时。通过半定量聚合酶链反应检测人白细胞介素-8（hIL-8）、人白细胞介素-8受体（hIL-8R）、小鼠白细胞介素-8受体（mIL-8R）、小鼠白细胞介素-6（mIL-6）、小鼠白细胞介素-6受体（mIL-6R）和人白细胞介素-6受体（hIL-6R）的mRNA表达水平。在两个共培养组中，与单独的Caco-2组相比，Caco-2细胞的hIL-8表达降低，而hIL-8R表达增加。在用LPS刺激后，两个共培养组中Caco-2细胞的hIL-8表达均高于Caco-2对照组。分离共培养组中Caco-2细胞hIL-8表达的增加与hIL-8R表达的降低和mIL-8R表达的增加相关。在混合共培养组中，hIL-8表达的增加与Caco-2细胞上hIL-8R表达的上调以及小鼠派尔集合淋巴结淋巴细胞（PPL）上mIL-8R表达的下调有关。在混合共培养中，LPS也上调了小鼠PPL中mIL-6的表达。然而，在用LPS处理后，混合共培养中Caco-2细胞的hIL-6R表达降低，而分离共培养中则增加。数据表明，上皮细胞释放的hIL-8可能通过旁分泌途径作用于淋巴细胞，但也可能通过自分泌途径作用于上皮细胞本身。数据还表明，派尔集合淋巴结淋巴细胞释放的mIL-6以旁分泌方式影响上皮细胞。
