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

BAILLO, AYELEN; VILLENA, JULIO; ALBARRACÍN, LEONARDO; TOMOKIYO, MIKADO; ELEAN, MARIANO; FUKUYAMA, KOHTARO; QUILODRÁN-VEGA, SANDRA; FADDA, SILVINA; KITAZAWA, HARUKI

Microorganisms

MDPI

Lugar: BASILEA; Año: 2022 vol. 11

: Currently, probiotic bacteria with not transferable antibiotic resistance represent a sustainable strategy for the treatment and prevention of enterotoxigenic Escherichia coli (ETEC) in farmanimals. 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. plantarumCRL681 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 micewere undertaken. Expression analysis indicated that both strains were able to trigger IL-6 and IL-8expression in PIE cells in steady-state conditions. Furthermore, mice orally treated with these strainshad significantly improved levels of IFN-γ and TNF-α in the intestine as well as enhanced activityof peritoneal macrophages. The ability of CRL681 and CRL1506 to beneficially modulate intestinalimmunity was further evidenced in ETEC-challenge experiments. In vitro, the CRL1506 and CRL681strains 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 ofboth strains to beneficially regulate the immune response against this pathogen. Moreover, the oraltreatment of mice with lactic acid bacteria (LAB) strains significantly reduced ETEC counts in jejunumand ileum and prevented the spread of the pathogen to the spleen and liver. Additionally, LABtreated-mice had improved levels of intestinal IL-10 both at steady state and after the challenge withETEC. The protective effect against ETEC infection was not observed for the non-immunomodulatoryTL2677 strain. Furthermore, the study showed that L. plantarum CRL1506 was more efficient thanthe CRL681 strain to modulate mucosal immunity highlighting the strain specific character of thisprobiotic activity. Our results suggest that the improved intestinal epithelial defenses and innateimmunity induced by L. plantarum CRL1506 and CRL681 would increase the clearance of ETEC and atthe same time, protect the host against detrimental inflammation. These constitute valuable featuresfor future probiotic products able to improve the resistance to ETEC infection.