Project description:Clarifying mechanisms underlying the selective adhesion of probiotics and competitive exclusion of pathogens in the intestine is a central theme of maintaining host health.
2023-07-20 | PXD036035 | Pride
Project description:Competitive exclusion prevents colonization and compartmentalization reduces transmission of ESBL-producing Escherichia coli in broilers
Project description:The intestinal ecosystem is balanced by dynamic interactions between resident and incoming microbes, the gastrointestinal barrier, and the mucosal immune system. However, in the context of inflammatory bowel diseases (IBD) where the integrity of the gastrointestinal barrier is compromised, resident microbes contribute to the development and perpetuation of inflammation and disease. In this context, probiotic bacteria exert beneficial effects enhancing epithelial barrier integrity. However, the mechanisms underlying these beneficial effects are only poorly understood. Here, we comparatively investigated the effects of four probiotic lactobacilli, namely L. acidophilus, L. fermentum, L. gasseri, and L. rhamnosus in a T84 cell epithelial barrier model. Results of DNA-microarray experiments indicating that lactobacilli modulate the regulation of genes encoding in particular adherence junction proteins such as E-cadherin and b-catenin were confirmed by qRT-PCR. Furthermore, we show that epithelial barrier function is modulated by Gram-positive probiotic lactobacilli via their effect on adherence junction protein expression and complex formation. In addition, incubation with lactobacilli differentially influences the phosphorylation of adherence junction proteins and of PKC isoforms such as PKCd which thereby positively modulates epithelial barrier function. Further insight into the underlying molecular mechanisms triggered by these probiotics might also foster the development of novel strategies for the treatment of gastrointestinal diseases (e.g. IBD).
Project description:The aim of this study was to examine the role of indigenous lactobacilli in the physiological development of the stomach in mice using microarray analysis. In lactobacilli-associated gnotobiotic mice, an increased expression of the genes related to the muscle system development, such as nebulin and troponin, was observed. On the other hand, the expression of the gastrin gene dramatically decreased. A microarray analysis of the stomachs infected with H. pylori also showed both the up-regulation of muscle cell genes and the down-regulation of gastrin genes. Male germfree BALB/c mice were orally inoculated with 109 CFU lactobacilli and their stomachs were excised after 10 days for analyses. In the other experiment, 8-week-old mice were orally inoculated using a stomach tube on three consecutive days with 109 CFU of H. pylori. The stomachs of the germfree mice were used as controls. For the DNA microarray analysis, RNA was prepared from the stomach and then applied to a genome array.
