Lactobacillus reuteri LR1 Improved Expression of Genes of Tight Junction Proteins via the MLCK Pathway in IPEC-1 Cells during Infection with Enterotoxigenic Escherichia coli K88.

Hongbo Yi,Yunxia Xiong,Xianyong Ma,Zongyong Jiang,Xuefen Yang,Yueqin Qiu,Zhilin Wang,Li Wang,Xiaolu Wen

doi:10.1155/2018/6434910

Hongbo Yi, Yunxia Xiong + Show 7 more

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https://doi.org/10.1155/2018/6434910

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Abstract

Intestinal epithelial barrier damage disrupts immune homeostasis and leads to many intestinal disorders. Lactobacillus reuteri strains have probiotic functions in their modulation of the microbiota and immune system in intestines. In this study, the effects of L. reuteri LR1, a new strain isolated from the feces of weaning piglets, on intestinal epithelial barrier damage in IPEC-1 cells caused by challenge with enterotoxigenic Escherichia coli (ETEC) K88 were examined. It was found that L. reuteri LR1, in large part, offset the ETEC K88-induced increase in permeability of IPEC-1 cell monolayers and decreased the adhesion and invasion of the coliform in IPEC-1 cells. In addition, L. reuteri LR1 increased transcript abundance and protein contents of tight junction (TJ) proteins zonula occluden-1 (ZO-1) and occludin in ETEC K88-infected IPEC-1 cells, whereas it had no effects on claudin-1 and F-actin expression. Using colloidal gold immunoelectron microscopy, these effects of L. reuteri LR1 on ZO-1 and occludin content in IPEC-1 cells were confirmed. By using ML-7, a selective inhibitor of myosin light-chain kinase (MLCK), the beneficial effect of L. reuteri LR1 on contents of ZO-1 and occludin was shown to be dependent on the MLCK pathway. In conclusion, L. reuteri LR1 had beneficial effects on epithelial barrier function consistent with increasing ZO-1 and occludin expression via a MLCK-dependent manner in IPEC-1 cells during challenge with ETEC K88.

Highlights

The intestinal epithelial barrier plays an essential role in the host defense against pathogen infection [1]
The transport of FITC-dextran in cells challenged with enterotoxigenic Escherichia coli (ETEC) K88 was significantly increased when compared with the control (Figure 1(a))
L. reuteri LR1 decreased the adhesion and invasion of ETEC K88 bacteria in the epithelial cells (Figure 1(b)). These results demonstrated that L. reuteri LR1 attenuated the ETEC K88-induced increase in the permeability of IPEC-1 cell monolayers

Summary

Introduction

The intestinal epithelial barrier plays an essential role in the host defense against pathogen infection [1]. Antibiotics have been widely used to treat intestinal diseases in past decades, recent studies have demonstrated that antibiotic exposure disrupts both the normal composition of intestinal microbiota and expression of TJ proteins damaging intestinal epithelial barrier function [9,10,11]. All this emphasizes the need to identify safe and effective agents for the treatment of intestinal diseases associated with damage to the epithelial barrier

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