Project description:To characterize the effect of microbiota on global gene expression in the distal small intestine during postnatal gut development we employed mouse models with experimental colonization by intestinal microbiota. Using microarray analysis to assess global gene expression in ileal mucosa at the critical stage of intestinal development /maturation associated with weaning, and asking how expression is affected by microbial colonization
Project description:To characterize the effect of microbiota on global gene expression in the distal small intestine during postnatal gut development we employed mouse models with experimental colonization by intestinal microbiota. Using microarray analysis to assess global gene expression in ileal mucosa at the critical stage of intestinal development /maturation associated with weaning, and asking how expression is affected by microbial colonization In the study presented here, preweaned and postweaned GF, SPF mouse small intestinal total RNAs were used. Also, 3-week-old gnotobiotic mouse as well as GF mouse small intestinal RNAs were used.
Project description:Purpose: Using a C57BL6/J mouse model of diet-induced obesity, we observed that mannose supplementation of high fat diet-fed mice prevents weight gain, lowers adiposity, reduces liver steatosis, and improves glucose tolerance and insulin sensitivity. Mannose increases Bacteroidetes to Firmicutes ratio of the gut microbiota, a signature previously associated with the lean phenotype. These beneficial effects of mannose are observed when supplementation is started early (3 weeks post weaning) but are lost when started later in life (8 weeks post weaning). We profiled transcriptomes of gut microbiota from high fat diet mice supplemented with or without mannose to understand the functional differences of supplementation at 3 weeks post weaning and 8 weeks post weaning. Method: Mice were weaned on high fat diet (HFD) or high fat diet with 2% mannose in drinking water (HFDM). RNA from each mouse for each diet group was isolated individually using Ambion RiboPure Bacteria kit (ThermoFisher Scientific). 1 mg cecal RNA each from 8 mice/diet group was pooled to generate 1 pool/diet for library preparation. The quality of total RNA was assessed by the Agilent Bioanalyzer Nano chip (Agilent Technologies). Total RNA was Ribo-depleted using Ribo-Zero Gold rRNA kit (Epidemiology) (Illumina). RNA-Seq library was constructed from the recovered non-ribosomal RNAs using Truseq Stranded total RNA library preparation kit (Illumina) as per the instructions. Multiplexed libraries were pooled and single-end 50-bp sequencing was performed using an Illumina Hiseq 1500. Results: The comparison of transcriptome profiles of mice supplemented with mannose at 3 weeks post weaning and 8 weeks post weaning shows mannose reduced transcript abundance for glycosyl hydrolases and carbohydrate metabolism when supplied at 3 weeks post weaning. Conclusion: The beneficial effects of mannose in responsive mice (3 weeks post weaning) are at least in part due to reduced energy harvest by gut microbes.
Project description:Abrupt weaning imposes highly variable physiological stress on pigs, yet the mechanisms underlying this variability remain poorly understood. We applied an integrative approach combining transcriptomics, gastrointestinal phenotyping, and blood biomarkers to characterize gut–brain axis dynamics at one week post‑weaning (day 7) and at the end of the nursery phase (day 39) in pigs with divergent early performance. Twenty‑four pigs of similar weaning weight (5.65 ± 1.0 kg) were selected from pens showing extreme early feed intake post-weaning and subsequently classified by average daily gain (ADG) as a proxy for individual feed intake (n = 12/timepoint). RNA sequencing of ileal and hypothalamic tissue revealed that low‑ADG pigs at day 7 exhibited impaired intestinal barrier function, suppressed metabolic and immune pathways, and hypothalamic activation of appetite‑suppressing (mTORC1, GLP‑1) and thermogenic signalling, together with endocrine disruption. By day 39, digestive and metabolic pathways were upregulated in the ileum of low‑ADG pigs, yet gut integrity deficits persisted alongside sustained hypothalamic immune activation and disrupted appetite signalling. Blood profiles indicated prolonged metabolic imbalance, characterized by elevated triglycerides, insulin, leptin, and TNF‑α, and reduced PYY. Collectively, these findings define a “low feed intake syndrome”, in which early nutrient deprivation, compromised gut integrity, and dysregulated neuroendocrine signalling converge to perpetuate poor growth and long‑term maladaptation.
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:During weaning, the transition to solid food diversifies the gut microbiome, triggering a programmed immune response critical for long-lasting mucosal immunity. Previous work showed that the gut microbiome mediates epigenetic development in intestinal stem cells (ISCs) during suckling, but what happens during weaning is unclear. Here, using genome-wide methylation profiling revealed that weaning-driven microbiome changes shape the DNA methylome and transcriptome of murine ISCs in an IFN-g dependent manner. Specifically, we observe demethylation of enhancer elements essential for MHC class II genes, which result in a transcriptional memory that persists through differentiation into adulthood. IFN-g blockade, or low-dose penicillin to target Gram-positive bacteria, in early life impaired microbiome-mediated epigenetic control and mucosal immunity, and exacerbated colitis. Murine organoids primed with IFN-g showed rapid, amplified transcriptional responses upon secondary stimulations. These findings reveal that early-life events alter the gut microbiome and these changes reprogram ISC epigenetic memory to shape mucosal immunity.