Surface proteins of Bifidobacterium bifidum DNG6 growing in 2′-fucosyllactose alleviating lipopolysaccharide-induced intestinal barrier injury in vitro

Human milk oligosaccharides promote the growth and adhesion of Bifidobacteria, thus exerting multiple biological functions on intestinal epithelial cells. Bacterial surface proteins play an important role in bacterial–host intestinal epithelial interactions. In this study, we aimed to investigate the effects of surface proteins extracted from Bifidobacterium bifidum DNG6 (B. bifidum DNG6) consuming 2′-fucosyllactose (2′-FL) on Caco-2 cells monolayer barrier injury induced by lipopolysaccharide, compared with lactose and galacto-oligosaccharides. Our results indicated that 2′-FL may promote the surface proteins of B. bifidum DNG6 to improve intestinal barrier injury by positively regulating the NF-κB signaling pathway, reducing inflammation (TNF-α reduced by 50.34%, IL-6 reduced by 22.83%, IL-1β reduced by 37.91%, and IL-10 increased by 63.47%) and strengthening tight junction proteins (ZO,1 2.39×; claudin,1 2.79×; and occluding, 4.70×). The findings of this study indicate that 2′-FL can further regulate intestinal barrier damage by promoting the alteration of B. bifidum DNG6 surface proteins. The findings of this research will also provide theoretical support for the development of synbiotic formulations.