Project description:Age-dependent changes of the gut-associated microbiome have been linked to increased frailty and systemic inflammation. This study found that age-associated changes of the gut microbiome of BALB/c and C57BL/6 mice could be reverted by co-housing of aged (22 months old) and adult (3 months old) mice for 30-40 days or faecal microbiota transplantation (FMT) from adult into aged mice. This was demonstrated using high-throughput sequencing of the V3-V4 hypervariable region of bacterial 16S rRNA gene isolated from faecal pellets collected from 3-4 months old adult and 22-23 months old aged mice before and after co-housing or FMT.
Project description:On going efforts are directed at understanding the mutualism between the gut microbiota and the host in breast-fed versus formula-fed infants. Due to the lack of tissue biopsies, no investigators have performed a global transcriptional (gene expression) analysis of the developing human intestine in healthy infants. As a result, the crosstalk between the microbiome and the host transcriptome in the developing mucosal-commensal environment has not been determined. In this study, we examined the host intestinal mRNA gene expression and microbial DNA profiles in full term 3 month-old infants exclusively formula fed (FF) (n=6) or breast fed (BF) (n=6) from birth to 3 months. Host mRNA microarray measurements were performed using isolated intact sloughed epithelial cells in stool samples collected at 3 months. Microbial composition from the same stool samples was assessed by metagenomic pyrosequencing. Both the host mRNA expression and bacterial microbiome phylogenetic profiles provided strong feature sets that clearly classified the two groups of babies (FF and BF). To determine the relationship between host epithelial cell gene expression and the bacterial colony profiles, the host transcriptome and functionally profiled microbiome data were analyzed in a multivariate manner. From a functional perspective, analysis of the gut microbiota's metagenome revealed that characteristics associated with virulence differed between the FF and BF babies. Using canonical correlation analysis, evidence of multivariate structure relating eleven host immunity / mucosal defense-related genes and microbiome virulence characteristics was observed. These results, for the first time, provide insight into the integrated responses of the host and microbiome to dietary substrates in the early neonatal period. Our data suggest that systems biology and computational modeling approaches that integrate “-omic” information from the host and the microbiome can identify important mechanistic pathways of intestinal development affecting the gut microbiome in the first few months of life. KEYWORDS: infant, breast-feeding, infant formula, exfoliated cells, transcriptome, metagenome, multivariate analysis, canonical correlation analysis 12 samples, 2 groups
Project description:The current treatment for Celiac Disease (CD) is adhering to a gluten-free diet (GFD), although its long-term molecular effects are still undescribed. New molecular features detectable in faecal samples may improve and facilitate non-invasive clinical management of CD on GFD. For this purpose, faecal small non-coding RNAs (sncRNAs) and gut microbiome profiles were concomitantly explored in CD subjects in relation to strict (or not) GFD adherence over time. In the present observational study, we performed small RNA and shotgun metagenomic sequencing in stool from 63 treated CD (tCD) subjects and 66 sex- and age-matched healthy controls. tCD included 51 individuals on strict GFD and with negative transglutaminase (TG) serology (tCD-TG-) and 12 symptomatic with not strict/short-time of GFD adherence and positive TG serology (tCD-TG+). Samples from additional 40 adult healthy individuals and from a cohort of 19 untreated paediatric CD subjects and 19 sex/age matched controls were analyzed to further test the outcomes. Several miRNA, other sncRNA (piRNA and tRNA) and microbiota profiles were altered in tCD subjects(adj.p<0.05). Findings were validated in one external group of controls. In tCD-TG-, GFD duration correlated with five miRNA levels (p<0.05): for miR-4533-3p and miR-2681-3p, the longer the diet adherence, the less the expression differed from controls. tCD-TG+ and untreated paediatric CD patients showed a similar miRNA dysregulation. Immune-response, trans-membrane transport and cell death pathways were enriched in targets of identified miRNAs. Bifidobacterium longum, Ruminococcus bicirculans and Haemophilus parainfluenzae abundances shifted (adj. p<0.05) with a progressive reduction of denitrification pathways with GFD length. Integrative analysis highlighted 121 miRNA-bacterial relationships (adj.p<0.05). Specific faecal sncRNA and microbial patterns characterise CD subjects on GFD, reflecting either the long-term effects or the gut inflammatory status, in case of a not strict/short-time adherence. Our findings suggest novel host-microbial interplays and could help the discovery of biomarkers for the clinical monitoring of GFD over time.
Project description:Colon cancer onset and progression is strongly associated with the presence, absence, or relative abundances of certain microbial taxa in the gastrointestinal tract. However, specific mechanisms affecting disease susceptibility related to complex bacterial mixtures are poorly understood. We used a multi-omics approach to determine how differences in the complex gut microbiome (GM) influence the metabolome and host transcriptome and ultimately affect susceptibility to adenoma development. Fecal samples collected from Pirc rats harboring two distinct complex GMs were analyzed using ultra-high performance liquid chromatography mass spectrometry (UHPLC-MS). We identified putative metabolite profiles that predicted future disease severity from samples collected prior to observable disease onset. Transcriptome analyses performed after disease onset on normal epithelium and tumor tissues suggests that the GM also alters the host transcriptome. Integrated pathway (IP) analyses of the metabolome and transcriptome based on putatively identified metabolic features indicate that bile acid biosynthesis was enriched in rats with high tumors (GM:F344) along with increased fatty acid metabolism and mucin biosynthesis. These data emphasize the utility of using untargeted metabolomics to identify metabolites for revealing signatures of susceptibility and resistance.
Project description:Background and Aims Interoceptive impacts on the brain triggered by changes in the intestinal microbial ecosystem influence mood-related behaviors such as anxiety and depression. Although changes in the gut microbiome can be driven by genetic mutations in the host, how alterations in the gut microbiome caused by host genetic variations affect behavioral outcomes is not fully understood. To investigate how host genetic variation affects interoceptive responses, we analyzed the gut microbiota and investigated gut–brain interactions in sirtuin 3 (Sirt3)-knockout (KO) mice. Methods We evaluated the composition of the gut microbiome and behavior in Sirt3-KO and wild-type (WT) mice. To distinguish microbiome-driven effects from genetic influences, we conducted cohousing experiments and compared results with heterozygous littermates. Region-specific changes in gene expression in the brain were identified by transcriptomic profiling of the limbic system. We also analyzed metabolites in the nucleus of the solitary tract (NTS) generated by gut microbiome–vagal signaling. The role of the vagus nerve in the gut-brain axis was further examined through vagotomy, alongside comparative choline analysis in both mood disorder patients and mice. Results Mood-related neurobehavioral changes and alterations in synaptic plasticity-related genes in the amygdala and bed nucleus of the stria terminalis (BNST) of Sirt3-KO mice appeared to be dependent on gut microbiome composition. Elevated plasma choline levels in both mood disorder patients and Sirt3-KO mice, together with reduced neurotransmitter-related metabolites (e.g., -aminobutyric acid [GABA] in the NTS), suggested that externalizing behaviors in Sirt3-KO mice are mediated by vagus nerve-dependent gut–brain axis signaling. Consistent with this, vagotomy abolished these changes, including GABA in the NTS, as well as alterations in synaptic plasticity in the amygdala and BNST. Conclusions Our findings suggest the novel finding that an altered gut microbiome caused by a host genetic change, namely a Sirt3 deficiency, is sensed in the NTS of the brain via the vagus nerve, leading to externalizing behaviors.
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: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.