Lactobacillus casei Zhang modulate cytokine and Toll-like receptor expression and beneficially regulate poly I:C-induced immune responses in RAW264.7 macrophages

Authors

  • Yuzhen Wang,

    1. College of Life Science, Inner Mongolia Agricultural University
    2. Key Laboratory of Dairy Biotechnology and Bioengineering, Education Ministry of China, College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018
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    • These authors contributed equally to this work.
  • Jiming Xie,

    1. Clinical Laboratory, Inner Mongolia People's Hospital, Hohhot 010017, China
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    • These authors contributed equally to this work.
  • Na Wang,

    1. College of Life Science, Inner Mongolia Agricultural University
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  • Yunxu Li,

    1. College of Life Science, Inner Mongolia Agricultural University
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  • Xiaolin Sun,

    1. College of Life Science, Inner Mongolia Agricultural University
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  • Yong Zhang,

    1. Key Laboratory of Dairy Biotechnology and Bioengineering, Education Ministry of China, College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018
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  • Heping Zhang

    Corresponding author
    1. Key Laboratory of Dairy Biotechnology and Bioengineering, Education Ministry of China, College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018
    • College of Life Science, Inner Mongolia Agricultural University
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Correspondence

Heping Zhang, Key Laboratory of Dairy Biotechnology and Bioengineering, Education Ministry of China, College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.

Tel: +86 471 4319940; fax: +86 471 4305357; email: hepingdd@vip.sina.com

Abstract

Lactobacilli are frequently used as probiotics due to their beneficial effects on health. Lactobacillus casei Zhang (LcZ), which has favorable probiotic properties, was first isolated from koumiss. In this study, the immunomodulating effects of LcZ on cytokine and toll-like receptor expression in RAW264.7 macrophages was assessed and it was found that live LcZ promotes production of nitric oxide (NO), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and interferon (IFN)-β. Transcription of inducible nitric oxide synthase (iNOS) was also enhanced by viable LcZ. The immunostimulating effects of live LcZ are significantly attenuated in heat-killed LcZ. Live LcZ promotes TLR2 mRNA transcription, whereas heat-killed LcZ enhances transcription of TLR2, TLR3, TLR4 and TLR9. Furthermore, live LcZ significantly suppresses polyinosinic:polycytidylic acid (poly I:C)-stimulated NO, iNOS and TNF-α expression while enhancing expression of IFN-β. It was also found that poly I:C-induced interferon regulatory factor 3 (IRF-3) reporter gene activity was significantly up-regulated by live LcZ. These results suggest that LcZ keeps the innate immune system alert by increasing transcription of Toll-like receptors and enhancing production of pro-inflammatory mediators and type I IFN in macrophages. The synergistic effect of live LcZ with poly I:C on IFN-β expression is associated with increased activity of IRF-3. LcZ has the potential to be used as an adjuvant against viral infections.

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