AUTHOR=Song Xiaofan , Pi Shanyao , Gao Yueming , Zhou Fengxia , Yan Shuqi , Chen Yue , Qiao Lei , Dou Xina , Shao Dongyan , Xu Chunlan 

TITLE=The Role of Vasoactive Intestinal Peptide and Mast Cells in the Regulatory Effect of Lactobacillus casei ATCC 393 on Intestinal Mucosal Immune Barrier

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.723173

DOI=10.3389/fimmu.2021.723173

ISSN=1664-3224

ABSTRACT=<p>Vasoactive intestinal peptide (VIP) plays an important role in the neuro-endocrine-immune system. Mast cells (MCs) are important immune effector cells. This study was conducted to investigate the protective effect of <italic>L. casei</italic> ATCC 393 on Enterotoxigenic <italic>Escherichia coli</italic> (ETEC) K88-induced intestinal mucosal immune barrier injury and its association with VIP/MC signaling by <italic>in vitro</italic> experiments in cultures of porcine mucosal mast cells (PMMCs) and <italic>in vivo</italic> experiments using VIP receptor antagonist (aVIP) drug. The results showed that compared with the ETEC K88 and lipopolysaccharides (LPS)-induced model groups, VIP pretreatment significantly inhibited the activation of MCs and the release of β-hexosaminidase (β-hex), histamine and tryptase. Pretreatment with aVIP abolished the protective effect of <italic>L. casei</italic> ATCC 393 on ETEC K88-induced intestinal mucosal immune barrier dysfunction in C57BL/6 mice. Also, with the blocking of VIP signal transduction, the ETEC K88 infection increased serum inflammatory cytokines, and the numbers of degranulated MCs in ileum, which were decreased by administration of <italic>L. casei</italic> ATCC 393. In addition, VIP mediated the regulatory effect of <italic>L. casei</italic> ATCC 393 on intestinal microbiota in mice. These findings suggested that VIP may mediate the protective effect of <italic>L.casei</italic> ATCC 393 on intestinal mucosal immune barrier dysfunction <italic>via</italic> MCs.</p>