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Open Access Research article

Advanced application of bovine intestinal epithelial cell line for evaluating regulatory effect of lactobacilli against heat-killed enterotoxigenic Escherichia coli-mediated inflammation

Naoya Takanashi1, Yohsuke Tomosada1, Julio Villena12, Kozue Murata1, Takuya Takahashi1, Eriko Chiba1, Masanori Tohno13, Tomoyuki Shimazu14, Hisashi Aso5, Yoshihito Suda6, Shuji Ikegami7, Hiroyuki Itoh7, Yasushi Kawai1, Tadao Saito1, Susana Alvarez2 and Haruki Kitazawa1*

Author Affiliations

1 Food and Feed Immunology Group, Laboratory of Animal Products Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Aoba-ku, 981-8555, Japan

2 Laboratory of Clinical and Experimental Biochemistry, Reference Centre for Lactobacilli (CERELA-CONICET), Tucuman, Argentina

3 National Agriculture and Food Research Organization, National Institute of Livestock and Grassland Science, Nasushiobara, 329-2793, Japan

4 Laboratory of Animal Breading and Genetics, Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555, Japan

5 Cell Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Aoba-ku, 981-8555, Japan

6 Department of Food, Agriculture and Environment, Miyagi University, Sendai, 982-0215, Japan

7 Division of Research and Development, Food Science Institute, Meiji Dairies Co, Kanagawa, Odawara, 250-0862, Japan

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BMC Microbiology 2013, 13:54  doi:10.1186/1471-2180-13-54

Published: 7 March 2013

Abstract

Background

Previously, a bovine intestinal epithelial cell line (BIE cells) was successfully established. This work hypothesized that BIE cells are useful in vitro model system for the study of interactions of microbial- or pathogen-associated molecular patterns (MAMPs or PAMPs) with bovine intestinal epithelial cells and for the selection of immunoregulatory lactic acid bacteria (LAB).

Results

All toll-like receptor (TLR) genes were expressed in BIE cells, being TLR4 one of the most strongly expressed. We demonstrated that heat-stable PAMPs of enterotoxigenic Escherichia coli (ETEC) significantly enhanced the production of IL-6, IL-8, IL-1α and MCP-1 in BIE cells by activating both NF-κB and MAPK pathways. We evaluated the capacity of several lactobacilli strains to modulate heat-stable ETEC PAMPs-mediated inflammatory response in BIE cells. Among these strains evaluated, Lactobacillus casei OLL2768 attenuated heat-stable ETEC PAMPs-induced pro-inflammatory response by inhibiting NF-κB and p38 signaling pathways in BIE cells. Moreover, L. casei OLL2768 negatively regulated TLR4 signaling in BIE cells by up-regulating Toll interacting protein (Tollip) and B-cell lymphoma 3-encoded protein (Bcl-3).

Conclusions

BIE cells are suitable for the selection of immunoregulatory LAB and for studying the mechanisms involved in the protective activity of immunobiotics against pathogen-induced inflammatory damage. In addition, we showed that L. casei OLL2768 functionally modulate the bovine intestinal epithelium by attenuating heat-stable ETEC PAMPs-induced inflammation. Therefore L. casei OLL2768 is a good candidate for in vivo studying the protective effect of LAB against intestinal inflammatory damage induced by ETEC infection or heat-stable ETEC PAMPs challenge in the bovine host.

Keywords:
Bovine intestinal epithelial cells; Immunobiotic; ETEC PAMPs; TLRs negative regulators; Lactobacillus casei OLL2768