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:D-galactose orally intake ameliorate DNCB-induced atopic dermatitis by modulating microbiota composition and quorum sensing. The increased abundance of bacteroidetes and decreased abundance of firmicutes was confirmed. By D-galactose treatment, Bacteroides population was increased and prevotella, ruminococcus was decreased which is related to atopic dermatitis.
Project description:Irritable Bowel Syndrome (IBS) is a disorder of the gut-brain axis, characterized by altered gut function and frequent psychiatric co-morbidity. Although altered intestinal microbiome profiles have been documented, their relevance to the clinical expression of IBS is unknown. To evaluate a functional role of the microbiota, we colonized germ-free mice with fecal microbiota from healthy controls or IBS patients with accompanying anxiety, and monitored gut function and behavior. Mouse microbiota profiles clustered according to their human donors. Despite having taxonomically similar composition as controls, mice with IBS microbiota had distinct serum metabolomic profiles related to neuro- and immunomodulation. Mice with IBS, but not control microbiota, exhibited faster gastrointestinal transit, intestinal barrier dysfunction, innate immune activation and anxiety-like behavior. These results support the notion that the microbiota contributes to both intestinal and behavioral manifestations of IBS and rationalize the use of microbiota-directed therapies in ameliorating IBS.
Project description:Recent studies in our lab have identified a mutant mouse model of obstructive nephropathy designated mgb for megabladder. Homozygotic mgb mice (mgb-/-) develop lower urinary tract obstruction in utero due to a lack of bladder smooth muscle differentiation. This defect is the result of a random transgene insertion into chromosome 16 followed by a translocation of this fragment into chromosome 11. In an effort to identify potential gene targets affected in mgb mice, we performed transcriptional profiling on embryonic day 15 (E15) mgb-/- bladders using both a Chromosome 11/16 Custom GeneChip Array and the Affymetrix Mouse Genome 430 2.0 GeneChip. This analysis identified no definitive mis-expressed gene targets on chromosome 11. In contrast, mgb-/- mice significantly over-expressed a cluster of gene products located on the translocated fragment of chromosome 16 including urotensin II-related peptide (Urp), which was shown to be preferentially over-expressed in developing mgb-/- bladders. Immunohistochemical studies indicated that the spatial distribution of Urp was altered in mgb-/- bladders, while biochemical studies suggested a potential role for Urp in modifying smooth muscle cell phenotype in vitro. Pathway analysis of mgb microarray data showed dysregulation of at least 60 gene products associated with the differentiation of smooth muscle. In conclusion, the results of this study indicate that the molecular pathways controlling normal smooth muscle development are severely altered in mgb-/- bladders, and provide the first evidence that Urp may play a critical role in bladder smooth muscle development. Keywords: mgb mutant bladders
Project description:Recent studies in our lab have identified a mutant mouse model of obstructive nephropathy designated mgb for megabladder. Homozygotic mgb mice (mgb-/-) develop lower urinary tract obstruction in utero due to a lack of bladder smooth muscle differentiation. This defect is the result of a random transgene insertion into chromosome 16 followed by a translocation of this fragment into chromosome 11. In an effort to identify potential gene targets affected in mgb mice, we performed transcriptional profiling on embryonic day 15 (E15) mgb-/- bladders using both a Chromosome 11/16 Custom GeneChip Array and the Affymetrix Mouse Genome 430 2.0 GeneChip. This analysis identified no definitive mis-expressed gene targets on chromosome 11. In contrast, mgb-/- mice significantly over-expressed a cluster of gene products located on the translocated fragment of chromosome 16 including urotensin II-related peptide (Urp), which was shown to be preferentially over-expressed in developing mgb-/- bladders. Immunohistochemical studies indicated that the spatial distribution of Urp was altered in mgb-/- bladders, while biochemical studies suggested a potential role for Urp in modifying smooth muscle cell phenotype in vitro. Pathway analysis of mgb microarray data showed dysregulation of at least 60 gene products associated with the differentiation of smooth muscle. In conclusion, the results of this study indicate that the molecular pathways controlling normal smooth muscle development are severely altered in mgb-/- bladders, and provide the first evidence that Urp may play a critical role in bladder smooth muscle development. Keywords: mgb mutant bladders Gene expression profiling was performed on two separate study groups. First, total cellular RNA was isolated from wildtype (n=2; 1 female/1 male), mgb+/- (n=2; 1 female/1 male), and mgb-/- (n=2; 1 female/1 male) E15 whole embryos. Second, total cellular RNA was isolated from the bladders of E15 wildtype (n=7; 3 female/4 male), mgb+/- mice (n=7; 3 female/4 male), and mgb-/- mice (n=11; 7 females/4 males).
Project description:The larynx is essential for swallowing, breathing, coughing, and voice production, supported by its unique microbial and immunological environment. Our previous research highlighted the role of resident laryngeal microbiota in shaping local immune responses. With growing interest in the gut-lung axis—the bidirectional communication between gut and respiratory immunity—the potential influence of gut microbiota on laryngeal immunity warrants exploration. We hypothesized that a gut-larynx axis may exist, where both resident laryngeal and gut microbiota contribute to immune modulation in the larynx. To investigate this, we treated conventionally raised, wild-type C57BL/6J mice with an oral antibiotic regimen known to disrupt gut microbiota, comparing them to untreated controls. Following treatment, the gut microbiota was significantly disrupted, while the laryngeal microbiota remained largely unchanged. However, antibiotic-treated mice exhibited marked changes in epithelial and immune cell proportions, as well as fibroblasts. Differential gene expression across cell types highlighted pathways related to epithelial barrier integrity, immune signaling, and bacterial response. Additionally, gut dysbiosis affected gene regulatory networks, with the activity of regulons Etv4(+), Irf3(+), Hltf(+), Mga(+), and Nfil3(+) showing significant changes. Notably, cell-cell communication was also altered, especially in immune-epithelial interactions, with integrin-mediated signaling emerging as a key ligand-receptor pathway in these intercellular communications. These findings suggest that gut and laryngeal microbiota may work synergistically to modulate immune responses in the larynx, underscoring the importance of considering gut-larynx interactions in studies of respiratory immunity.
Project description:The gut microbiota exerts a profound influence on host physiology, but its systemic impact on gene expression across diverse tissues remains poorly characterized. This study investigated the transcriptional effects of gut microbiota depletion and restoration in mice across six tissues (colon, jejunum, liver, heart, lung, and kidney) using whole-transcriptome sequencing. We found that the presence of gut microbiota significantly altered the transcriptome, with the most pronounced effects in the colon. Using a linear mixed-effects model, we identified 7,365 effector genes. Tissue-specific analysis revealed that these genes were associated with distinct functional pathways, such as immunity in the gut and lung, and metabolism in the liver. Further refinement with LASSO regression pinpointed gut microbiota-mediated key effector genes, whose expression levels were significantly associated with patient survival in corresponding human cancers (e.g., LIHC, LUAD, KIRC). Furthermore, we observed a widespread remodeling of competing endogenous RNA (ceRNA) networks by the gut microbiota. Single-cell data analysis highlighted a potential gut-liver axis interaction, primarily mediated by colonic enterocytes and hepatic cholangiocytes, meanwhile gut microbiota repressed the transcription initiation of Noct in colonic enterocytes, whose expression level was significantly negatively correlated to gut-liver axis interaction. Our findings provide a comprehensive map of the multi-tissue transcriptional landscape shaped by the gut microbiota, revealing tissue-specific regulatory mechanisms and identifying key genes with potential clinical relevance in cancer.
Project description:We have previously demonstrated that the gut microbiota can play a role in the pathogenesis of conditions associated with exposure to environmental pollutants. It is well accepted that diets high in fermentable fibers such as inulin can beneficially modulate the gut microbiota and lessen the severity of pro-inflammatory diseases. Therefore, we aimed to test the hypothesis that hyperlipidemic mice fed a diet enriched with inulin would be protected from the pro-inflammatory toxic effects of PCB 126.