Project description:Alterations in gut microbiota have been implicated in the pathogenesis of Colorectal Cancer (CRC). Here we collected fecal samples from 14 CRC patients and 14 healthy volunteer cohorts, and characterized their microbiota using label-free quantitative metaproteomics method. We have quantified 30,062 gut microbial protein groups, 91,902 peptides, and 195 genera of microbes, among which 341 proteins were found significantly different in abundance between the CRC patients and healthy volunteers. Our study demonstrates that gut bacteria involve in CRC pathogenesis not only via taxonomy abundance variations but also functional activity changes.
Project description:Dysbiotic configurations of the human gut microbiota have been linked with colorectal cancer (CRC). Human small non-coding RNAs are also implicated in CRC and recent findings suggest that their release in the gut lumen contributes to shape the gut microbiota. Bacterial small RNAs (bsRNAs) may also play a role in carcinogenesis but their role is less explored. Here, we performed small RNA and shotgun sequencing on 80 stool specimens of patients with CRC, or adenomas, and healthy subjects collected in a cross-sectional study to evaluate their combined use as a predictive tool for disease detection. We reported a considerable overlap and correlation between metagenomic and bsRNA quantitative taxonomic profiles obtained from the two approaches. Furthermore, we identified a combined predictive signature composed by 32 features from human and microbial small RNAs and DNA-based microbiome able to accurately classify CRC from healthy and adenoma samples (AUC= 0.87). In summary we reported evidence that host-microbiome dysbiosis in CRC can be observed also by altered small RNA stool profiles. Integrated analyses of the microbiome and small RNAs in the human stool may provide insights for designing more accurate tools for diagnostic purposes.
Project description:Gut microbiota dysbiosis characterizes systemic metabolic alteration, yet its causality is debated. To address this issue, we transplanted antibiotic-free conventional wild-type mice with either dysbiotic (“obese”) or eubiotic (“lean”) gut microbiota and fed them either a NC or a 72%HFD. We report that, on NC, obese gut microbiota transplantation reduces hepatic gluconeogenesis with decreased hepatic PEPCK activity, compared to non-transplanted mice. Of note, this phenotype is blunted in conventional NOD2KO mice. By contrast, lean microbiota transplantation did not affect hepatic gluconeogenesis. In addition, obese microbiota transplantation changed both gut microbiota and microbiome of recipient mice. Interestingly, hepatic gluconeogenesis, PEPCK and G6Pase activity were reduced even once mice transplanted with the obese gut microbiota were fed a 72%HFD, together with reduced fed glycaemia and adiposity compared to non-transplanted mice. Notably, changes in gut microbiota and microbiome induced by the transplantation were still detectable on 72%HFD. Finally, we report that obese gut microbiota transplantation may impact on hepatic metabolism and even prevent HFD-increased hepatic gluconeogenesis. Our findings may provide a new vision of gut microbiota dysbiosis, useful for a better understanding of the aetiology of metabolic diseases. all livers are from NC-fed mice only.
Project description:The ERC “MINERVA” project (GA 724734) aims at developing a multi-organ-on-a-chip engineered platform to recapitulate in vitro the main players involved in the MGBA crosstalk: the microbiota, the gut epithelium, the immune system, the blood-brain barrier and the brain. In this context, the gut epithelium represents a physiological barrier that separates the intestinal lumen from the systemic circulation, and in several pathological circumstances, seems that its permeability might significantly increase and allow the passage of biologically active molecules into the blood vessels surrounding the intestinal mucosa. In the present work, we present our MINERVA 2.0 device and our innovative gut-on-a-chip device obtained by culturing in MINERVA 2.0 and a human gut epithelial CaCo2 cell based model. In particular, we have cultured the cells under perfusion and have assessed cell behavior by addressing cellular viability, tight junction imaging, apparent permeability by FITC-Dextran and transepithelial electrical resistance evaluation. Transcriptomic profile was used to further elucidate the effects of dynamic perfusion on Caco-2 cells.
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:Metaproteomic portrait of the healthy human gut microbiota. Re-analysis of existing datasets, selected based on the following inclusion criteria: human cohort including at least 5 healthy (clearly not labeled as diseased) adult (>18 years old) individuals; data derived from LC-MS/MS DDA label-free analysis of fecal samples (with neither subcellular fractionation of microbial cells nor offline fractionation of peptides); availability of raw MS data on public repositories.
Project description:A recently layer of gene expression regulation is N6-methyladenosine (m6A) mRNA modification. The role of gut microbiota in modulating host m6A epitranscriptomic and gene expression has not been studied. To decipher the role of gut microbiome, we profiled m6A mRNA modification epitranscriptomic mark in conventional mice compared to germ free mice. Transcriptome-wide mapping of host m6A mRNA modifications in four mice tissues allowed us to discover that gut microbiota can greatly impact host m6A mRNA modifications. The expression levels of m6A writers in mice tissues are regulated by gut microbiota. In conclusion, we report transcriptome-wide mapping of host m6A mRNA modifications regulated by gut microbiota. The present study can help better understand the role of the microbiome in host gene expression and host-microbiome interactions.