The effect of probiotic Lactobacilli strains, inulin-type fructans and oligofructose on gene expression profiles in intestinal Caco-2 cells

Background: Beneficial microbes can be actors in maintaining or stimulating barrier function, and may counteract pathogen-infection. Lactobacilli are particularly recognized for enhancing intestinal barrier function and to confer protective effects against multiresistant pathogens. Various L. acidophilus strains support intestinal immune barrier function and have been shown to improve resistance to pathogens. Although less extensively studied than beneficial bacteria, other food-based ingredients that can contribute to strengthening barrier function are dietary fibers. For instance, inulin and fructooligosaccharides (FOS) have recently been shown to enhance barrier function and protect against barrier dysfunction. Effects of these ingredients on intestinal barrier function were evaluated by quantifying regulation of gene expression by microarray. Methods: Caco-2 cells were incubated with probiotic strains or inulin-type fibers for 6 hours, total RNA was extracted and Affymterix Human Gene 1.1 ST arrays were used to analyze the gene expression profiles. Results: Only L. acidophilus modulated a group of 26 genes related to tight-junctions. Inulin-type fructans, L. brevis W63 and L. casei W56 regulated other genes, unrelated to tight junctions. L. acidophilus also had unique effects on a group of 6 genes regulating epithelial phenotype towards follicle-associated epithelium. L. acidophilus W37 was therefore selected for a challenge with STM and prevented STM-induced barrier disruption and decreased secretion of IL-8. L. acidophilus W37 increases TEER and can protect against STM induced disruption of gut epithelial cells integrity in vitro. Conclusion: Our results suggest that selection of specific bacterial strains for enforcing barrier function may be a promising strategy to reduce or prevent STM infections.

23

Lépine AFP, de Wit N, Oosterink E, Wichers H, Mes J, de Vos P