Altered expression of inflammatory cytokine receptors in response to LPS challenge through interaction between intestinal epithelial cells and lymphocytes of Peyer's patch

Authors

  • Jie Chen,

    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
    2. Children's Hospital of Chongqing Medical University, Chongqing 400014, China
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  • Chuen Pei Ng,

    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
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  • Lai Ling Tsang,

    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
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  • Lok Sze Ho,

    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
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  • Peng Hui Xu,

    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
    2. Department of Immunology, Institute of Microbiology and Epidemiology, Academy of Military Medical Science, Beijing 100810, China
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  • Dewi Kenneth Rowlands,

    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
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  • Jie Ying Gao,

    1. Department of Immunology, Institute of Microbiology and Epidemiology, Academy of Military Medical Science, Beijing 100810, China
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  • Yiu Wa Chung,

    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
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  • Ting Yu Li,

    1. Children's Hospital of Chongqing Medical University, Chongqing 400014, China
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  • Hsiao Chang Chan

    Corresponding author
    1. Epithelial Cell Biology Research Centre, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Department of Physiology, Shatin, Hong Kong
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Tel.: +852 26096839; fax: +852 26035022. E-mail addresses: hsiaocchan@cuhk.edu.hk

Abstract

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.

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