Evaluating the Effectiveness of Lactobacillus zeae against Enterotoxigenic Escherichia coli F4 Infection in an In Vitro Porcine Intestinal Epithelial Cell Model

Abstract

Lactobacillus zeae (LB1 strain) has been shown to prevent the death of Caenorhabditis elegans caused by enterotoxigenic Escherichia coli (ETEC) infection by downregulating the gene expression of ETEC toxins and mediating antimicrobial peptides/defense molecules under the p38 mitogen-activated protein kinase (MAPK) and insulin/insulin-like growth factor (DAF/IGF) signaling pathways in the nematode. However, the protective effects of L. zeae LB1 at cellular and molecular levels have not yet been investigated in pigs. In this study, porcine intestinal cells (IPEC-J2) were used to investigate the potential of L. zeae LB1 in modulating intestinal barrier and innate immune functions and protecting against intestinal injuries and inflammatory reactions induced by ETEC F4 infection. The results showed that the pretreatment of IPEC-J2 cells with L. zeae LB1 significantly alleviated the ETEC F4-induced elevation of pro-inflammatory cytokines and damage in the cell monolayer (P < 0.05). Whereas L. zeae LB1 administration had no effect (P > 0.05) on the ETEC F4 adhesion and the mRNA abundance of antimicrobial defensins (pBD2 and pBD3), it reduced the mRNA abundance of Toll-like receptor 4 and 5 (TLR4 and -5, respectively) and virulence-related factors of ETEC F4 (P < 0.05). Moreover, a DNA marker-based test targeting the mucin 4 gene that encodes the F4 fimbria receptor indicated that the IPEC-J2 cell line was from a pig that was identified as being resistant to developing ETEC-F4 diarrhea. These results suggested that probiotic L. zeae LB1 effectively protected the intestinal cells from ETEC F4 infection by inhibiting inflammation and maintaining barrier integrity via downregulating TLR4, TLR5, and ETEC F4 virulence-related factors expression instead of preventing ETEC F4 adhesion. Our data provide further evidence of the mechanisms at the cellular and molecular levels that probiotic L. zeae LB1 could improve gut health in pigs.

Functional evaluation of Bacillus licheniformis PF9 for its potential in controlling enterotoxigenic Escherichia coli in weaned piglets

“…Thus, B. licheniformis PF9 could be a promising alternative to antibiotics. This observation is consistent with a previous study described by Chen et al. (2021) , which may in part be explained by enhanced gut barrier function with increased mRNA expression of the tight junction proteins ZO-1 and OCLN in the jejunum detected in the present study.…”

Post-weaning diarrhea and use of feedstuffs in pigs

“…Those short-chain fatty acids are considered a useful energy source utilized by pigs to develop the large intestine ( den Besten et al, 2013 ). Recent studies have identified the protective effect of Bacillus strains on intestinal cells challenged with enteric pathogenic bacteria, since they found the pre-treatment of Bacillus could upregulate tight junction protein expression and decrease quorum sensing ( Chen et al, 2021 ; Li et al, 2022a , 2022 b). For weaned piglets, including lactic acid-producing bacteria in their dies could relieve weaning stress, reduce diarrhea, and enhance growth performance ( Yang et al, 2015a , 2015b ).…”

Complete Genome Sequencing and Comparative Genomics of Three Potential Probiotic Strains, Lacticaseibacillus casei FBL6, Lacticaseibacillus chiayiensis FBL7, and Lacticaseibacillus zeae FBL8

“…L. chiayiensis was first isolated in 2018 from cow manure (Huang et al, 2018), and since then, this species has not been reported anymore. L. zeae, designated as an independent species from L. casei in 2020, has been said to exhibit antimicrobial activity against two strains of enterotoxigenic Escherichia coli (Zhou et al, 2014;Huang et al, 2020;Chen et al, 2021).…”