Project description:In the presented study, in order to unravel gut microbial community multiplicity and the influence of maternal milk nutrients (i.e., IgA) on gut mucosal microbiota onset and shaping, a mouse GM (MGM) was used as newborn study model to discuss genetic background and feeding modulation on gut microbiota in term of symbiosis, dysbiosis and rebiosis maintenance during early gut microbiota onset and programming after birth. Particularly, a bottom-up shotgun metaproteomic approach, combined with a computational pipeline, has been compred with a culturomics analysis of mouse gut microbiota, obtained by MALDI-TOF mass spectrometry (MS).
Project description:Dietary lipids can affect metabolic health through gut microbiota-mediated mechanisms, but the influence of lipid-microbiota interaction on liver steatosis is unknown. We investigated the effect of dietary lipid composition on human microbiota in an observational study and combined diet experiments with microbiota transplants to study lipid-microbiota interactions and liver status in mice. In humans, low intake of saturated fatty acids (SFA) was associated with increased microbial diversity independent of fiber intake. In mice, cecum levels of SFA correlated negatively with microbial diversity and were associated with a shift in butyrate and propionate producers. Mice fed poorly absorbed SFA had improved metabolism and liver status. These features were transmitted by microbial transfer. Diets enriched in n-6- and/or n-3-polyunsaturated fatty acids were protective against steatosis but had minor influence on the microbiota. In summary, we find that unabsorbed SFA correlate with microbiota features that may be targeted to decrease liver steatosis.
Project description:It has been widely recognized that the microbiota has the capacity to shape host gene expression and physiological functions. However, there remains a paucity of comprehensive study revealing host transcriptional landscape regulated by the microbiota. Here, we comprehensively examined mRNA landscapes in mouse tissues (brain and cecum) from specific pathogen free (SPF) and germ-free mouse (GF) using Nanopore direct RNA sequencing. Our results show that the microbiome has global influence on host’s RNA modifications (m6A, m5C, Ψ), isoform generation, poly(A) tail length (PAL), and transcript abundance in both brain and cecum tissues. Moreover, the microbiome exerts tissue-specific effects on various post-transcriptional regulatory processes. In addition, the microbiome impacts the coordination of multiple RNA modifications in host brain and cecum tissues. In conclusion, we establish the relationship between microbial regulation and gene expression, our results help the understanding of the mechanisms by which the microbiome reprograms host gene expression.
Project description:The intestinal microbiota modulates host physiology and gene expression via mechanisms that are not fully understood. A recently discovered layer of gene expression regulation is N6-methyladenosine (m6A) and N6,2′ -O-dimethyladenosine (m6Am) modifications of mRNA. To unveil if these epitranscriptomic marks are affected by the gut microbiota, we performed methylated RNA-immunoprecipitation and sequencing (MeRIP-seq) to examine m6A-modifications in transcripts of mice displaying either a conventional, or a modified, or no gut microbiota and discovered that the microbiota has a strong influence on m6A- modifications in the cecum, and also, albeit to a lesser extent, in the liver, affecting pathways related to metabolism, inflammatory and antimicrobial responses . We furthermore analysed expression levels of several known writer and eraser enzymes and found the methyltransferase Mettl16 to be downregulated in absence of a microbiota. As a consequence, one of its targets, the S-adenosyl methionine synthase Mat2a was less expressed in mice without gut flora. We furthermore show that distinct commensal bacteria, Akkermansia muciniphila, Lactobacillus plantarum can affect specific m6A modifications. Together, we report here epitranscriptomic modifications as an additional level of interaction in the complex interplay between commensal bacteria and their host.
Project description:It has been widely recognized that the microbiota has the capacity to shape host gene expression and physiological functions. However, there remains a paucity of comprehensive study revealing host transcriptional landscape regulated by the microbiota. Here, we comprehensively examined mRNA landscapes in mouse tissues (brain and cecum) from specific pathogen free (SPF) and germ-free mouse (GF) using Nanopore direct RNA sequencing. Our results show that the microbiome has global influence on host’s RNA modifications (m6A, m5C, Ψ), isoform generation, poly(A) tail length (PAL), and transcript abundance in both brain and cecum tissues. Moreover, the microbiome exerts tissue-specific effects on various post-transcriptional regulatory processes. In addition, the microbiome impacts the coordination of multiple RNA modifications in host brain and cecum tissues. In conclusion, we establish the relationship between microbial regulation and gene expression, our results help the understanding of the mechanisms by which the microbiome reprograms host gene expression.
Project description:A rapid ex vivo microbiome assay and metaproteomics approach was used for rapid evaluation of the cultivability of bio-banked live microbiota, which shows minimal detrimental influences of long-term freezing in deoxygenated glycerol buffer on the cultivability of fecal microbiota.
Project description:The long-term study objective is to develop optimized nutritional therapies for surgery and test them in clinical practice. This pilot study will test a microbiome-optimization diet in colorectal cancer surgery patients. The study hypothesizes that the Bacterial Intestinal Gut Modification Around Cancer Surgery (BIG MACS) Diet will provide participants with increased microbiota accessible carbohydrates (MACs) to support the microbiome and improve outcomes.
Project description:<p>We investigate the hypothesis that consistent changes in the human gut microbiome are associated with Crohn's disease, a form of inflammatory bowel disease, and that altered microbiota contributes to pathogenesis. Analysis of this problem is greatly complicated by the fact that multiple factors influence the composition of the gut microbiota, including diet, host genotype, and disease state. For example, data from us and others document a drastic impact of diet on the composition of the gut microbiome. No amount of sequencing will yield a useful picture of the role of the microbiota in disease if samples are confounded with uncontrolled variables.</p> <p>We aim to characterize the composition of the gut microbiome while controlling for diet, host genotype, and disease state. Diet is controlled by analyzing children treated for Crohn's disease by placing them on a standardized elemental diet, and by testing effects of different diets on the gut microbiome composition in adult volunteers. Genotype is analyzed by large scale SNP genotyping, which is already underway and separately funded--team member Hakon Hakonarson is currently genotyping 50 children a week at ~half a million loci each and investigating connections with inflammatory bowel disease. Clinical status is ascertained in the very large IBD practice in the UPenn/CHOP hospital system. Effects of diet, host genotype, and disease state on the gut microbiome are summarized in a multivariate model, allowing connections between microbiome and disease to be assessed free of confounding factors.</p> <p>This project is divided into four sub-studies. In the Fecal Storage Methods (FSM) study, methods of stool storage and DNA extraction are compared to examine their impact on DNA sequence analysis results. The Controlled Feeding Experiment (CaFE) addresses the effects of controlled diets on the gut microbiome. In the Cross-sectional Study of Diet and Stool Microbiome Composition (COMBO), the effects of diet analyzed using surveys and deep sequencing of stool specimens. The fourth study, Pediatric Longitudinal Study of Elemental Diet and Stool Microbiome Composition (PLEASE), examines the effects of an elemental diet treatment on pediatric patients diagnosed with inflammatory bowel disease (IBD), particularly Crohn's disease.</p> <p> <ul> <li>Fecal Storage Methods (FSM): Cross-sectional study</li> <li>Controlled Feeding Experiment (CaFE): Controlled trial</li> <li>Cross-sectional Study of Diet and Stool Microbiome Composition (COMBO): Cross-sectional study</li> <li>Pediatric Longitudinal Study of Elemental Diet and Stool Microbiome Composition (PLEASE): Longitudinal cohort study</li> </ul> </p>