Project description:Nowadays, Western diets and lifestyle lead to an increasing occurrence of chronic gut inflammation, that represents an emerging health concern with still a lack of successful therapies. Fermented foods, and their associated Lactic Acid Bacteria, have recently regained popularity for their probiotic potential including the maintenance of gut homeostasis by modulating the immune and inflammatory response. Our study aims to investigate the cross-talk between the food-borne strain Lactiplantibacillus plantarum C9O4 and intestinal epithelial cells in an in vitro inflammation model. Cytokines profile shows the ability of C9O4 to significantly reduce levels of IL-2, IL-5, IL-6, and IFN-γ. Proteomic functional analysis reveals an active host-microbe interaction that highlights an immunoregulatory role of C9O4, able to revert both the detrimental effects of IFN-γ through the JAK/STAT pathway and the apoptosis process in inflamed cells. These results suggest a promising therapeutic role of fermented food-associated microbes for the management of gastrointestinal inflammatory diseases.
Project description:Background: Probiotic-like bacteria treatment has been described to be associated with gut microbiota modifications. Goal: To decipher if the effects of the tested probiotic-like bacteria are due to the bacteria itself or due to the effects of the bacteria on the gut microbiota. Methodology: In this study, gut microbiota has been analyzed from feces samples of subjects with metabolic syndrome and treated with one of the 2 tested probiotic-like bacteria or with the placebo during 3months.
Project description:Gut microbiota is a constant source of antigens and stimuli to which the resident immune system has developed tolerance. However, the mechanisms by which mononuclear phagocytes, specifically monocytes/macrophages, cope with these usually pro-inflammatory signals is poorly understood. Here, we show that innate immune memory promotes anti-inflammatory homeostasis using as a model strains of the commensal bacterium, Lactiplantibacillus plantarum. Priming of monocytes/macrophages with bacteria, especially in its live form, enhances bacterial intracellular survival and decreases the release of pro-inflammatory signals to the environment, with lower production of TNF and higher levels of IL-10. Analysis of the transcriptomic landscape of these cells shows downregulation of pathways associated with the production of reactive oxygen species (ROS) and the release of cytokines, chemokines and antimicrobial peptides. Indeed, the induction of ROS prevents memory-induced bacterial survival. In addition, there is a dysregulation in gene expression of several metabolic pathways leading to decreased glycolytic and respiratory rates in memory cells. These data support commensal microbe-specific metabolic changes in innate immune memory cells that might contribute to homeostasis in the gut.
Project description:The indigenous human gut microbiota is a major contributor to the human superorganism with established roles in modulating nutritional status, immunity, and systemic health including diabetes and obesity. The complexity of the gut microbiota consisting of over 1012 residents and approximately 1000 species has thus far eluded systematic analyses of the precise effects of individual microbial residents on human health. In contrast, health benefits have been shown upon ingestion of certain so-called probiotic Lactobacillus strains in food products and nutritional supplements, thereby providing a unique opportunity to study the global responses of a gut-adapted microorganism in the human gut and to identify the molecular mechanisms underlying microbial modulation of intestinal physiology, which might involve alterations in the intestinal physico-chemical environment, modifications in the gut microbiota, and/or direct interaction with mucosal epithelia and immune cells. Here we show by transcriptome analysis using DNA microarrays that the established probiotic bacterium, L. plantarum 299v, adapts its metabolic capacity in the human digestive tract for carbohydrate acquisition and expression of exo-polysaccharide and proteinaceous cell surface compounds. This report constitutes the first application of global gene expression profiling of a gut-adapted commensal microorganism in the human gut. Comparisons of the transcript profiles to those obtained for L. plantarum WCFS1 in germ-free mice revealed conserved L. plantarum responses indicative of a core transcriptome expressed in the mammalian gut and provide new molecular targets for determining microbial-host interactions affecting human health. Hybridization of the samples against a common reference of gDNA isolated from L. plantarum 299v
Project description:The indigenous human gut microbiota is a major contributor to the human superorganism with established roles in modulating nutritional status, immunity, and systemic health including diabetes and obesity. The complexity of the gut microbiota consisting of over 1012 residents and approximately 1000 species has thus far eluded systematic analyses of the precise effects of individual microbial residents on human health. In contrast, health benefits have been shown upon ingestion of certain so-called probiotic Lactobacillus strains in food products and nutritional supplements, thereby providing a unique opportunity to study the global responses of a gut-adapted microorganism in the human gut and to identify the molecular mechanisms underlying microbial modulation of intestinal physiology, which might involve alterations in the intestinal physico-chemical environment, modifications in the gut microbiota, and/or direct interaction with mucosal epithelia and immune cells. Here we show by transcriptome analysis using DNA microarrays that the established probiotic bacterium, L. plantarum 299v, adapts its metabolic capacity in the human digestive tract for carbohydrate acquisition and expression of exo-polysaccharide and proteinaceous cell surface compounds. This report constitutes the first application of global gene expression profiling of a gut-adapted commensal microorganism in the human gut. Comparisons of the transcript profiles to those obtained for L. plantarum WCFS1 in germ-free mice revealed conserved L. plantarum responses indicative of a core transcriptome expressed in the mammalian gut and provide new molecular targets for determining microbial-host interactions affecting human health.
Project description:Droplet digital polymerase chain reaction (ddPCR) is one of the newest and most promising tools providing absolute quantification of target DNA molecules. Despite its emerging applications in microorganisms, few studies reported its use for detecting lactic acid bacteria. This study evaluated the applicability of a ddPCR assay targeting molecular genes obtained from in silico analysis for detecting Lactiplantibacillus plantarum subsp. plantarum, a bacterium mainly used as a starter or responsible for fermentation in food. The performance characteristics of a ddPCR were compared to those of a quantitative real-time PCR (qPCR). To compare the linearity and sensitivity of a qPCR and ddPCR, the calibration curve for a qPCR and the regression curve for a ddPCR were obtained using genomic DNA [102−108 colony-forming units (CFU)/mL] extracted from a pure culture and spiked food sample. Both the qPCR and ddPCR assays exhibited good linearity with a high coefficient of determination in the pure culture and spiked food sample (R2 ≥ 0.996). The ddPCR showed a 10-fold lower limit of detection, suggesting that a ddPCR is more sensitive than a qPCR. However, a ddPCR has limitations in the absolute quantitation of high bacterial concentrations (>106 CFU/mL). In conclusion, a ddPCR can be a reliable method for detecting and quantifying lactic acid bacteria in food.