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:BACKGROUND: MicroRNAs negatively regulate gene expression and play a pivotal role in the pathogenesis of human type 2 diabetes mellitus (T2DM). As the domestic cat presents a spontaneous animal model for human T2DM, the purpose of this study was to investigate whether microRNAs are detectable in feline serum and whether microRNA expression profiles differ between healthy and diabetic cats. METHODS: Total RNA was extracted from 400 µl serum of healthy lean (HL) and newly diagnosed diabetic (D) cats. MicroRNA microarrays representing 1079 distinct mouse miRNA targets were used to measure miRNA expression in samples from eight HL and eight D cats. RESULTS: By microarray, 227 distinct microRNAs were identified. Nineteen miRNAs were differentially expressed in diabetic cats, but only two reached statistical significance after correction for multiple comparisons. In qRT-PCR, miR-122* was found to be upregulated in diabetic cats more than 40-fold compared to HL cats, while miR-193b was upregulated about 10-fold. MiR-483* showed a 6- fold increase in diabetic cats compared to HL cats. CONCLUSIONS: Small volumes of serum samples yield sufficient material to detect altered microRNA expression profiles in diabetic cats. The domestic cat may be considered a useful animal model for studying miRNAs involved in human T2DM.