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:Studies have emphasized the importance of disease-associated microorganisms in perturbed communities, however, the protective roles of commensals are largely under recognized and poorly understood. Using acne as a model disease, we investigated the determinants of the overall virulence property of the skin microbiota when disease- and health-associated organisms coexist in the community. By ultra-deep metagenomic shotgun sequencing, we revealed higher relative abundances of propionibacteria and Propionibacterium acnes phage in healthy skin. In acne patients, the microbiome composition at the species level and at P. acnes strain level was more diverse than in healthy individuals, with enriched virulence-associated factors and reduced abundance of metabolic synthesis genes. Based on the abundance profiles of the metagenomic elements, we constructed a quantitative prediction model, which classified the clinical states of the host skin with high accuracy in... (for more see dbGaP study page.)
Project description:Samples from the ISS were processed using 50% MeOH as an extraction solvent and ran on a Bruker Daltonics maXis Impact and C18 RP-UHPLC. This data-set contains only positive polarity acquisition of LC-MS/MS and FASTA files for each species
Project description:Inflammatory bowel disease (IBD) is associated with altered microbiota composition and metabolism, but it is unclear whether these changes precede inflammation or are the result of it since current studies have mainly focused on changes after the onset of disease. We previously showed differences in mucus gut microbiota composition preceded colitis-induced inflammation and stool microbial differences only became apparent at colitis onset. In the present study, we aimed to investigate whether microbial dysbiosis was associated with differences in both predicted microbial gene content and endogenous metabolite profiles. We examined the functional potential of mucus and stool microbial communities in the mdr1a -/- mouse model of colitis and littermate controls using PICRUSt on 16S rRNA sequencing data. Our findings indicate that despite changes in microbial composition, microbial functional pathways were stable before and during the development of mucosal inflammation. LC-MS-based metabolic phenotyping (metabotyping) in urine samples confirmed that metabolite profiles in mdr1a -/- mice were remarkably unaffected by development of intestinal inflammation and there were no differences in previously published metabolic markers of IBD. Metabolic profiles did, however, discriminate the colitis-prone mdr1a -/- genotype from controls. Our results indicate resilience of the metabolic network irrespective of inflammation. Importantly as metabolites differentiated genotype, genotype-differentiating metabolites could potentially predict IBD risk.
Project description:Study generating and describing the faecal metagenomes of 194 persons occupationally exposed to antimicrobial resistance in livestock (including 46 control subjects).
- DNA of faecal samples of 194 persons occupationally exposed to antimicrobial resistance (AMR) in livestock, i.e. persons living or working on pig and poultry farms and pig slaughterhouse workers and control subjects, was sequenced and metagenomically analysed.
- The faecal resistomes and microbiomes of farmers and slaughterhouse workers were described and compared between occupationally exposed groups and controls.
- We found an increased ARG carriage in persons working in the Dutch pork production chain as compared to poultry farmers and controls.
- Significant differences were found in the resistome and bacteriome composition of pig and pork exposed workers compared to a control group, as well as within-population (farms, slaughterhouse) compositional differences.
- On-farm working hours and working or living on a pig farm (versus poultry farm) are determinants for the human faecal resistome.
- Direct or indirect contact with AMR in livestock may be a determinant for human ARG carriage.
Project description:The tet methylcytosine dioxygenase 2 (TET2) enzyme catalyzes the conversion of the modified DNA base 5-methylcytosine to 5-hydroxymethylcytosine. TET2 is frequently mutated or dysregulated in multiple human cancers, and loss of TET2 is associated with changes in DNA methylation patterns. Here, using newly developed TET2-specific antibodies and the estrogen response as a model system for studying the regulation of gene expression, we demonstrate that endogenous TET2 occupies active enhancers and facilitates the proper recruitment of ERalpha. Knockout of TET2 by CRISPR-CAS9 leads to a global increase of DNA-methylation at enhancers resulting in attenuation of the estrogen response. We further identified a positive feedback loop between TET2 and ERalpha, which further requires MLL3/COMPASS at these enhancers. Together, this study reveals an epigenetic axis coordinating a transcriptional program through enhancer activation via DNA demethylation. Overall design: To examine changes in histone modifications, ER-alpha occupancy, MLL3 occupancy, and gene expression changes after depletion of TET2 in human breast cancer cell lines.
Project description:Peripheral innervation plays an important role in regulating tissue repair and regeneration. Here, we provide evidence that injured peripheral nerves provide a reservoir of mesenchymal precursor cells that can directly contribute to murine digit tip regeneration and skin repair. In particular, using single-cell RNA sequencing and lineage tracing we identify transcriptionally-distinct mesenchymal cell populations within the control and injured adult nerve, including neural crest-derived cells in the endoneurium with characteristics of mesenchymal precursor cells. Culture and transplantation studies show that these nerve-derived mesenchymal cells have the potential to differentiate into non-nerve lineages. Moreover, following digit tip amputation, the neural crest-derived nerve mesenchymal cells contribute to the regenerative blastema and ultimately to the regenerated bone. Similarly, neural crest derived nerve mesenchymal cells contribute to the dermis during skin wound healing. These findings support a model where peripheral nerves directly contribute mesenchymal precursor cells to promote repair and regeneration of injured mammalian tissues. Overall design: We have applied the high-throughput single-cell mRNA sequencing technique, Drop seq, to the sciatic nerves of adult CD1 and C57BL/6 mice. Processed data for 3 samples are included: 2 injured nerve and one uninjured nerve sample (predicted mesenchymal cells only).
Project description:In meiotic prophase, chromosomes are organized into compacted loop arrays to promote homolog pairing and recombination. Here, we probe the architecture of the mouse spermatocyte genome in early and late meiotic prophase using Hi-C. We show that early-prophase chromosomes are arranged as linear arrays of 0.8-1 Mb loops, which extend to 1.5-2 Mb in late prophase as chromosomes compact and homologs undergo synapsis. Topologically associating domains (TADs) are lost in meiotic prophase, suggesting that assembly of the meiotic chromosome axis dramatically reduces the dynamics of chromosome-associated cohesin complexes. While TADs are lost, physically-separated A and B compartments are maintained in meiotic prophase. Moreover, meiotic DNA breaks and inter-homolog crossovers preferentially form in the gene-dense A compartment, revealing a role for chromatin organization in meiotic recombination. Finally, direct detection of inter-homolog contacts genome-wide reveals the structural basis for homolog alignment and juxtaposition by the synaptonemal complex. Overall design: Hi-C detection of intra- and inter-homolog contacts in B6 x CAST F1 hybrid mouse spermatocytes. Two independent biological replicates of zygonema-stage spermatocytes, and three independent biological replicates of pachynema-stage spermatocytes.
Project description:The health impacts of endocrine disrupting chemicals (EDCs) remain debated and their tissue and molecular targets are poorly understood. Here, we leveraged systems biology approaches to assess the target tissues, molecular pathways, and gene regulatory networks associated with prenatal exposure to the model EDC Bisphenol A (BPA). Prenatal BPA exposure led to scores of transcriptomic and methylomic alterations in the adipose, hypothalamus, and liver tissues in mouse offspring, with cross-tissue perturbations in lipid metabolism as well as tissue-specific alterations in histone subunits, glucose metabolism and extracellular matrix. Network modeling prioritized main molecular targets of BPA, including Pparg, Hnf4a, Esr1, Srebf1, and Fasn. Lastly, integrative analyses identified the association of BPA molecular signatures with cardiometabolic phenotypes in mouse and human. Our multi-tissue, multi-omics investigation provides strong evidence that BPA perturbs diverse molecular networks in central and peripheral tissues, and offers insights into the molecular targets that link BPA to human cardiometabolic disorders. Overall design: We utilized next-generation sequencing technologies to characterize perturbations in both the transcriptome (RNA-seq) and the epigenome (RRBS) across three tissues (white adipose tissue, hypothalamus, liver) in mouse offspring who had experienced in utero exposure to BPA