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 gut microbiota, immune system, and enteric nervous system interact to regulate adult gut physiology. Yet the mechanisms establishing gut physiology during development remain unknown. We report that in developing zebrafish, enteroendocrine cells produced IL-22 in response to microbial signals before lymphocytes populate the gut. In larvae, IL-22 shaped the gut microbiota, increased Lactobacillaceae abundance and ghrelin expression to promote gut motility. Impaired motility and ghrelin expression were restored in il22-/- zebrafish by transfer of microbiota from wild-type zebrafish or by monoassociation with Lactobacillus plantarum. IL-22-deficient mice had impaired gut motility and reduced ghrelin expression in early life too, indicating a conserved function. Thus, before immune system maturation, enteroendocrine cells regulate early-life gut function by controlling the microbiota via IL-22.
Project description:The mammalian gastrointestinal tract contains a diverse ecosystem of microbial species collectively making up the gut microbiome. Emerging evidence highlights a critical relationship between gut microbiota and neurocognitive development. Consumption of unhealthy yet palatable dietary factors associated with obesity and metabolic dysfunction (e.g., saturated fat, added sugar) produces microbiota dysbiosis and negatively impacts neurocognitive function, particularly when consumed during early life developmental periods. Here we explore whether excessive early life consumption of added sugars negatively impacts neurocognitive development via the gut microbiome. Using a rodent model of habitual sugar-sweetened beverage (SSB) consumption during the adolescent stage of development, we first show that excessive early life sugar intake impairs hippocampal-dependent memory function when tested during adulthood while preserving other neurocognitive domains. Gut microbiome genomic sequencing analyses reveal that early life SSB consumption alters the abundance of various bacterial populations, including elevations in operational taxonomic units within the genus Parabacteroides (P. distasonis and P. johnsonii) whose abundance negatively correlated with memory task performance. Additional results reveal that in vivo Parabacteroides enrichment of cultured P. distasonis and P. johnsonii bacterial species in adolescent rats severely impairs memory function during adulthood. Hippocampus transcriptome analyses identify gene expression alterations in neurotransmitter synaptic signaling, intracellular kinase signaling, metabolic function, neurodegenerative disease, and dopaminergic synaptic signaling-associated pathways as potential mechanisms linking microbiome outcomes with memory impairment. Collectively these results identify microbiota dysbiosis as a mechanism through which early life unhealthy dietary patterns negatively impact neurocognitive outcomes.
Project description:The evolutional trajectory of gut microbial colonization from birth has been shown to prime for health later in life. Here, we combined cultivation-independent 16S rRNA gene sequencing and metaproteomics to investigate the functional maturation of gut microbiota in faecal samples from full-term healthy infants collected at 6 and 18 months of age. Phylogenetic analysis of the metaproteomes showed that Bifidobacterium provided the highest number of distinct protein groups. Considerable divergences between taxa abundance and protein phylogeny were observed at all taxonomic ranks. Age had a profound effect on early microbiota where compositional and functional complexity of less dissimilar communities increased with time. Comparisons of the relative abundances of proteins revealed the transition of taxon-associated saccharolytic and carbon metabolism strategies from catabolic pathways of milk and mucin-derived monosaccharides feeding acetate/propanoate synthesis to complex food sugars fuelling butyrate production. Furthermore, co-occurrence network analysis uncovered two anti-correlated modules of functional taxa. A low-connected Bifidobacteriaceae-centred guild of facultative anaerobes was succeeded by a rich club of obligate anaerobes densely interconnected around Lachnospiraceae, underpinning their pivotal roles in microbial ecosystem assemblies. Our findings establish a framework to visualize whole microbial community metabolism and ecosystem succession dynamics, proposing opportunities for microbiota-targeted health-promoting strategies early in life.
Project description:To characterize the effect of microbiota on global gene expression in the distal small intestine during postnatal gut development we employed mouse models with experimental colonization by intestinal microbiota. Using microarray analysis to assess global gene expression in ileal mucosa at the critical stage of intestinal development /maturation associated with weaning, and asking how expression is affected by microbial colonization In the study presented here, preweaned and postweaned GF, SPF mouse small intestinal total RNAs were used. Also, 3-week-old gnotobiotic mouse as well as GF mouse small intestinal RNAs were used.
Project description:The early life microbiome plays important roles in host immunological and metabolic development. Because type 1 diabetes (T1D) incidence has been increasing substantially in recent decades, we hypothesized that early-life antibiotic use alters gut microbiota that predisposes to disease. Using NOD mice that are genetically susceptible to T1D, we examined the effects of exposure to either continuous low-dose antibiotics or pulsed therapeutic antibiotics (PAT) early in life, mimicking childhood exposures. We found that in mice receiving PAT, T1D incidence was significantly higher, microbial community composition and structure differed compared with controls. In pre-diabetic male PAT mice, the intestinal lamina propria had lower Th17 and T reg proportions and intestinal SAA expression than in controls, suggesting key roles in transducing the altered microbiota signals. PAT affected microbial lipid metabolism and host cholesterol biosynthetic gene expression. These findings show that early-life antibiotic treatments alter the gut microbiota and its metabolic capacities, intestinal gene expression, and T-cell populations, accelerating T1D onset in NOD mice.
Project description:The main goal of this study is to decipher the role of CSD in the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation
Project description:Metaproteomic analysis of mouse gut microbiota in the early life: taxonomic, functional and quantitative analysis to evaluate breastfeeding modulation
Project description:We transplanted gut microbiota via fecal transfer from TD and ASD children into germ-free wild-type mice, and reveal that colonization with ASD microbiomes induces hallmark changes in sociability, vocalization, and stereotypies. The brains of mice receiving gut microbiota from ASD individuals display alternative splicing patterns for genes dysregulated in the human ASD brain.
Project description:The period from birth to two years is the phase of the fastest growth and development in children, as well as an important window for the development of intestinal microbiota. Dysbiosis of the gut microbiome can lead to various adverse conditions in children, including malabsorption and immune abnormalities, ultimately resulting in a series of negative events related to growth and development. Lysine acetylation, as a significant post-translational modification, plays a complex and crucial role in the regulation of gut microbiota. This study aims to investigate the mechanism by which ABX-induced lysine acetylation affects the abnormal physiological state simulating gut microbiota dysbiosis in children. In this study, we identified a total of 16,579 acetylation sites from 5,218 proteins. We found that antibiotic-induced dysbiosis in young mice (3 weeks) can cause extensive changes in the lysine acetylation and proteomic profiles of cecal tissue. Differentially acetylated proteins are involved in various metabolic pathways, including the citrate cycle (TCA) cycle, butanoate metabolism, pyruvate metabolism, glycolysis/gluconeogenesis, and fatty acid biosynthesis. These differential acetylation sites are distributed across the cytoplasm, nucleus, and mitochondria, suggesting that multiple cellular functions are involved in regulation. Our findings suggest that early-life gut microbiota dysbiosis may lead to a series of metabolic disorders by regulating lysine acetylation in cecal tissue, resulting in delayed growth and development. This study aims to provide valuable insights into the molecular mechanisms underlying a series of pathophysiological processes caused by early-life gut microbiota dysbiosis. It contributes to a deeper understanding of the consequences of acetylation changes associated with early-life gut microbiota dysbiosis and its potential role in metabolic disorders.