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Bacillus amyloliquefaciens exopolysaccharides promote the defensive and protective functions of intestinal epithelial cells
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  • Hsueh-Ling Cheng,
  • Wei-Wen Sung,
  • Chien-Ming Tseng,
  • Lin-Lee Lee
Hsueh-Ling Cheng
National Pingtung University of Science and Technology Department of Biological Science and Technology

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Wei-Wen Sung
National Pingtung University of Science and Technology Department of Biological Science and Technology
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Chien-Ming Tseng
National Pingtung University of Science and Technology Department of Biological Science and Technology
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Lin-Lee Lee
National Kaohsiung Normal University
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Abstract

Bacillus amyloliquefaciens was demonstrated to improve gut health, ameliorate inflammation, and enhance immunity in animal models, but underlying mechanisms are unclear. This study investigated the effects of the exopolysaccharides (EPS) of B. amyloliquefaciens amy-1 on the intestinal epithelium, further exploring the mechanisms underlying the probiotic function of B. amyloliquefaciens. The expression of mucin 1, inducible nitric oxide synthase, cyclooxygenase-2, interleukine-8, antimicrobial peptides TFF-3, β-defensin 2, S100A8, S100A9, and RegIII-α were all increased in EPS- or lipopolysaccharide (LPS)-treated Caco-2 cells, suggesting that EPS enhanced the defensive abilities of intestinal cells. However, unlike LPS, EPS did not activate the inhibitor kappa B kinase/tumor necrosis factor-α (TNF-α) pathway, indicating that EPS did not cause inflammation. Moreover, EPS enhanced the barrier function of cells; the underlying mechanism was likely associated with enhanced expression of tight-junction proteins. EPS activated the nuclear factor erythroid-2 related factor 2/heme oxygenase-1 pathway and decreased the level of reactive oxygen species, whereas LPS did not, suggesting that EPS improved the protective functions of the epithelium. Confocal microscopic images showed EPS binding to cell surfaces and internalizing into cells, whereas dextran, another microbial exopolysaccharide, did not. Together, our data suggest that EPS are involved in the probiotic function of B. amyloliquefaciens.