Seaweed polysaccharide mitigates intestinal barrier dysfunction induced by enterotoxigenic Escherichia coli through NF-κB pathway suppression in porcine intestinal epithelial cells |
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| Authors: | Xiaobo Guo Jun Chen Jin Yang Qin He Bowen Luo Yafei Lu Tiande Zou Zirui Wang Jinming You |
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| Affiliation: | 1. Jiangxi Province Key Laboratory of Animal Nutrition, Jiangxi Province Key Innovation Center of Integration in Production and Education for High-quality and Safe Livestock and Poultry, Jiangxi Agricultural University, Nanchang, China
Gannan Academy of Sciences, Ganzhou, China;2. Jiangxi Province Key Laboratory of Animal Nutrition, Jiangxi Province Key Innovation Center of Integration in Production and Education for High-quality and Safe Livestock and Poultry, Jiangxi Agricultural University, Nanchang, China |
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| Abstract: | This study aimed to investigate the protective effects and underlying mechanism of seaweed polysaccharide (SWP) on intestinal epithelial barrier dysfunction induced by E. coli in an IPEC-J2 model. A preliminary study was done to screen optimum SWP concentrations by cell viability, cytotoxicity, apoptosis and proliferation evaluation. The regular study was conducted to evaluate the protective effects of SWP against E. coli challenge via the analysis of transepithelial electrical resistance (TEER), tight junction proteins, NF-κB signalling pathway, proinflammatory cytokines and the E. coli adhesion and invasion. Our results show that 4 h E. coli challenge down-regulated tight junction proteins expression, decreased TEER, activated NF-κB signalling pathway and increased proinflammatory response, which indicates that the E. coli infection model was well-established. Pre-treatment with 240 μg/ml SWP for 24 h alleviated the 4 h E. coli -induced intestinal epithelial barrier dysfunction, as evidenced by the up-regulated expression of Occludin, Claudin-1 and ZO-1 at both mRNA and protein level and the increased TEER of IPEC-J2 cells. Pre-incubation with 240 μg/ml SWP for 24 h inhibited the activation of the NF-κB signalling pathway by 4 h E. coli challenge, including the decreased mRNA expression of TLR-4, MyD88, IκBα, p-65, as well as the reduced ratio of protein expression of p-p65/p65. Also, pre-treatment with 240 μg/ml SWP for 24 h decreased proinflammatory response (IL-6 and TNF-α) induced by 4 h E. coli challenge and decreased the E. coli adhesion and invasion. In conclusion, SWP mitigated intestinal barrier dysfunction caused by E. coli through NF-κB pathway in IPEC-J2 cells and 240 μg/ml SWP exhibited better effect. Our results also provide a fundamental basis for SWP in reducing post-weaning diarrhoea of weaned piglets, especially under E. coli -infected or in-feed antibiotic-free conditions. |
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| Keywords: | Escherichia coli intestinal barrier dysfunction IPEC-J2 cells NF-κB pathway seaweed polysaccharide |
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