<i>Lactobacillus fermentum</i>(MTCC‐5898) alleviates<i>Escherichia coli</i>‐induced inflammatory responses in intestinal epithelial cells by modulating immune genes and NF‐κB signalling

Abstract

AIM: Dietary intervention using probiotic bacteria has emerged as a promising preventive strategy in addressing foodborne infections or gastrointestinal disorders. This study investigated the immunomodulatory effects of Lactobacillus fermentum (MTCC-5898) on Escherichia coli-induced inflammatory responses in intestinal epithelial cells. METHODS AND RESULTS: The immune response of intestinal cells (Caco-2) in the presence of probiotic Lact. fermentum was determined during exclusion, competition and displacement of E. coli as the inflammatory agent. To achieve this objective, transcriptional modulation of key immune-related genes (cytokines, pattern recognition receptors and NF-κB), release of cytokines and nuclear translocation of the NF-κB subunit p-65 were studied. Expression of pro-inflammatory cytokines IL-8, TNF-α, IFN-ϒ and IL-23 was high in E. coli-exposed intestinal cells. However, overexpression of these E. coli-induced pro-inflammatory cytokines was prevented by Lact. fermentum during exclusion and competition assays. It also modulated the transcriptional expression of regulatory cytokines (IL-10 and TGF-β), pattern recognition receptors (TLR-2 and TLR-4) and genes associated with master inflammatory regulators (NF-κB and SIGIRR) to reduce E. coli-induced inflammation. The protective effect of Lact. fermentum was further confirmed by suppression of nuclear translocation of cytoplasmic NF-κB subunit (p-65). CONCLUSION: Lactobacillus fermentum alleviated E. coli-induced inflammatory responses by modulating the NF-κB signalling besides pro-inflammatory and regulatory cytokines expression. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus fermentum holds significant promise as a potent nutraceutical that prevents and manages inflammatory gut-associated dysfunctions.

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