Project description:Gut microbiome research is rapidly moving towards the functional characterization of the microbiota by means of shotgun meta-omics. Here, we selected a cohort of healthy subjects from an indigenous and monitored Sardinian population to analyze their gut microbiota using both shotgun metagenomics and shotgun metaproteomics. We found a considerable divergence between genetic potential and functional activity of the human healthy gut microbiota, in spite of a quite comparable taxonomic structure revealed by the two approaches. Investigation of inter-individual variability of taxonomic features revealed Bacteroides and Akkermansia as remarkably conserved and variable in abundance within the population, respectively. Firmicutes-driven butyrogenesis (mainly due to Faecalibacterium spp.) was shown to be the functional activity with the higher expression rate and the lower inter-individual variability in the study cohort, highlighting the key importance of the biosynthesis of this microbial by-product for the gut homeostasis. The taxon-specific contribution to functional activities and metabolic tasks was also examined, giving insights into the peculiar role of several gut microbiota members in carbohydrate metabolism (including polysaccharide degradation, glycan transport, glycolysis and short-chain fatty acid production). In conclusion, our results provide useful indications regarding the main functions actively exerted by the gut microbiota members of a healthy human cohort, and support metaproteomics as a valuable approach to investigate the functional role of the gut microbiota in health and disease.
Project description:The aim of this study was to characterize the transcriptional signature of MDR1+ human memory T cells isolated from clinically inflamed gut tissue, and compare it to local MDR1- memory T cells Human mononuclear cells were isolated from the peripheral blood of a healthy adult donor (Ficol density centrifugation) or from resected lesioned gut tissue of a patient with active Crohn's disease. For cell isolation from gut tissue, tissue was rinsed with PBS, treated with 0.15% DTT to remove mucous, then with 1 mM EDTA to remove epithelial cells and intra-epithelial lymphocytes. Remaining tissue was digested using Liberase-TL (Roche) plus 10 U/mL DNase I. Mononuclear cells were then filtered through 70 mM nylon filters and isolated via a 30%/ 70% Percol gradient. Mononuclear cells from blood or gut tissue were FACS-sorted into CD3+ CD4+ CD45RO+ MDR1+ or MDR1- memory T cells, using Rhodamine 123 (Rh123) efflux as a surrogate for MDR1 expression/ activity. Sorted cells were harvested directly ex vivo (without further in vitro culture or manipulation) prior to RNA extraction. MDR1- memory CD4+ T cells vs. MDR1+ memory CD4+ T cells from healthy donor peripheral blood or from active Crohn's disease lesioned tissue; MDR1- or MDR1+ memory CD4+ T cells from blood vs. inflamed gut tissue
Project description:Gut dysbiosis is closely involved in the pathogenesis of inflammatory bowel disease (IBD). However, it remains unclear whether IBD-associated gut dysbiosis plays a primary role in disease manifestation or is merely secondary to intestinal inflammation. Here, we established a humanized gnotobiotic (hGB) mouse system to assess the functional role of gut dysbiosis associated with two types of IBD - Crohn's disease (CD) and ulcerative colitis (UC). In order to explore the functional impact of dysbiotic microbiota in IBD patients on host immune responses, we analyzed gene expression profiles in colonic mucosa of hGB mice colonized with healty (HC), CD, and UC microbiota.