Intestinal Epithelial-Protective Effects of Leuconostoc mesenteroides H40 in LPS-Stimulated HT-29 Cells.

In this study, the intestinal epithelial-protective effects of Leuconostoc mesenteroides H40 (H40) were investigated using HT-29 intestinal epithelial cells. H40 reduced nitric oxide production in sodium nitroprusside (SNP)-treated cells and suppressed the lipopolysaccharide (LPS)-induced gene expression of inflammatory mediators, including interleukin-1 beta (IL-1β), IL-6, IL-8, TNF-α, and COX-2. In addition, it attenuated the LPS-induced decrease in intestinal barrier-related genes, including ZO-1, claudin-1, occludin, JAM1, and MUC2, which was further supported by preserved or enhanced protein levels of claudin-1, occludin, and MUC2. Furthermore, H40 attenuated the LPS-induced reductions in TPH1 and SERT expression at both the mRNA and protein levels, suggesting a potential influence on serotonin-related molecular pathways in intestinal epithelial cells. Genome annotation revealed that H40 harbors genes associated with exopolysaccharide biosynthesis, cell wall/membrane-associated functions, cell-surface anchoring, antioxidant defense, tryptophan and aromatic amino acid metabolism, and B-vitamin metabolism, indicating that these genomic features may support its intestinal epithelial-protective potential and gut-brain axis-related functionality. Collectively, these findings revealed that H40 exerts anti-inflammatory, intestinal epithelial-protective effects, accompanied by modulation of intestinal barrier- and serotonin-related markers. These results indicate that H40 may represent a promising probiotic candidate for supporting intestinal epithelial health.