Lactiplantibacillus plantarum Strains Modulate Intestinal Innate Immune Response and Increase Resistance to Enterotoxigenic Escherichia coli Infection

Abstract

Currently, probiotic bacteria with not transferable antibiotic resistance represent a sustainable strategy for the treatment and prevention of enterotoxigenic Escherichia coli (ETEC) in farm animals. Lactiplantibacillus plantarum is among the most versatile species used in the food industry, either as starter cultures or probiotics. In the present work, the immunobiotic potential of L. plantarum CRL681 and CRL1506 was studied to evaluate their capability to improve the resistance to ETEC infection. In vitro studies using porcine intestinal epithelial (PIE) cells and in vivo experiments in mice were undertaken. Expression analysis indicated that both strains were able to trigger IL-6 and IL-8 expression in PIE cells in steady-state conditions. Furthermore, mice orally treated with these strains had significantly improved levels of IFN-γ and TNF-α in the intestine as well as enhanced activity of peritoneal macrophages. The ability of CRL681 and CRL1506 to beneficially modulate intestinal immunity was further evidenced in ETEC-challenge experiments. In vitro, the CRL1506 and CRL681 strains modulated the expression of inflammatory cytokines (IL-6) and chemokines (IL-8, CCL2, CXCL5 and CXCL9) in ETEC-stimulated PIE cells. In vivo experiments demonstrated the ability of both strains to beneficially regulate the immune response against this pathogen. Moreover, the oral treatment of mice with lactic acid bacteria (LAB) strains significantly reduced ETEC counts in jejunum and ileum and prevented the spread of the pathogen to the spleen and liver. Additionally, LAB treated-mice had improved levels of intestinal IL-10 both at steady state and after the challenge with ETEC. The protective effect against ETEC infection was not observed for the non-immunomodulatory TL2677 strain. Furthermore, the study showed that L. plantarum CRL1506 was more efficient than the CRL681 strain to modulate mucosal immunity highlighting the strain specific character of this probiotic activity. Our results suggest that the improved intestinal epithelial defenses and innate immunity induced by L. plantarum CRL1506 and CRL681 would increase the clearance of ETEC and at the same time, protect the host against detrimental inflammation. These constitute valuable features for future probiotic products able to improve the resistance to ETEC infection.

Usage of Cultured Human Fecal Microbiota for Colonization of Caenorhabditis elegans to Study Host–Microbe Interaction

“…When fed soil bacteria, the innate immune system has been shown to be an important factor for shaping the resulting worm microbiota [24]. The innate immune system is also involved with mediating a beneficial effect of probiotic bacteria [17,43] and it is most likely also determining which subset of the human microbiota can colonize the bacteria. However, many additional genetic factors determining microbiota colonization and effects on the host are likely to exist, which can be studied with a sub-microbiota of cHFM.…”

Synergistic Effect of B-Type Lotus Seedpod Oligomeric Procyanidin and Probiotics against Adhesion of Enterotoxigenic Escherichia coli In Vitro

“…SCFAs are degradation products of undigested carbohydrates by intestinal microorganisms, which could reshape the gut ecology, induce immunomodulatory and antibiotic activity, and mediate infammatory signaling cascade during gut infammation [40]. Banerjee et al found that probiotics seem to improve other characteristics such as SCFAs production [11,12]. Te increased secretion of SCFAs in the intestine acidifes the colonic environment, promotes the absorption of minerals, and combats the invasion of pathogenic bacteria [35,41].…”

“…Ren et al reported that the probiotic Lactobacillus paracasei ameliorated diarrhea by inhibiting the activation of the nuclear factor kappa B/MLCK pathway and increasing the abundance of short-chain fatty acids (SCFAs)-producing gut microbiota in mice [11]. In addition, Baillo et al demonstrated that Lactiplantibacillus plantarum strains can modulate intestinal innate immune response, thereby increasing the ETEC clearance in mice [12]. Nevertheless, available evidence also suggests that the antiinvasive efect of probiotics on ETEC is closely related to the type and action mode of probiotics [13,14], which needs further comparative study.…”