Kinetics of L cells transcriptional profiling over the course of colonization in germ-free mice
Ontology highlight
ABSTRACT: L cells are one of enteroendocrine cells. Germ-free reporter mouse strain for L cell was colonized with unfractionated microbiota from conventional mouse. Lpos populations were sorted using FACS at D1, D3 and D7 following colonization and were subjected to transcriptional profiling to understand kinetics of transcriptional profiling over the course of colonization.
Project description:L cells are one of enteroendocrine cells. To understand the role of gut microbiota in its regulation, germ-free and conventional reporter mouse strain was used to sort Lpos and Lneg populations using FACS. The cell population were sorted from both ileum and colon and were subjected to transcriptional profiling.
Project description:The mammalian gut harbors a diverse microbial community (gut microbiota) that mainly consists of bacteria. Their combined genomes (the microbiome) provide biochemical and metabolic functions that complement host physiology. Maintaining symbiosis seems to be a key requirement for health as dysbiosis is associated with the development of common diseases. Previous studies indicated that the microbiota and the hostM-bM-^@M-^Ys epithelium signal bidirectional inducing transcriptional responses to fine-tune and maintain symbiosis. However, little is known about the hostM-bM-^@M-^Ys responses to the microbiota along the length of the gut as earlier studies of gut microbial ecology mostly used either colonic or fecal samples. This is of importance as not only function and architecture of the gut varies along its length but also microbial distribution and diversity. Few recent studies have begun to investigate microbiota-induced host responses along the length of the gut. However, these reports used whole tissue samples and therefore do not allow drawing conclusions about specificity of the observed responses. Which cells in the intestinal tissue are responsible for the microbially induced response: epithelial, mesenchymal or immune cells? Where are the responding cells located? Furthermore, the gut microbiota has been implicated in epigenetic regulation of the hostM-bM-^@M-^Ys transcriptional profile. We used using extensive microarray analysis of laser capture microdissection (LCM) harvested ileal and colonic tip and crypt fractions from germ-free mice before and during the time course of colonization with a normal microbiota (on days 1, 3, 5 and 7) to investigate the microbiota-induced transcriptional responses and their kinetics in specific and well-defined cell populations of the hostM-bM-^@M-^Ys epithelium. Ileum and colon segments were dissected from germ-free 10-12 weeks old female C57Bl/6 mice and on day 1, 3, 5 and 7 after colonization, washed and frozen as OCT blocks. Cryosections were prepared from these OCT blocks and tip/crypt fractions isolated using laser capture microdissection. To investigate the microbiota-induced transcriptional responses specific for specific subpopulations of intestinal epithelial cells and their kinetics, tip and crypt fractions of ileal and colonic epithelium of germ-free 10-12 weeks old female C57Bl/6 mice before and during the time course of colonization with a normal microbiota (on days 1, 3, 5 and 7) were harvested using laser capture microdissection and probed in an extensive microarray analysis.
Project description:Endogenous intestinal microbiota have wide-ranging and largely uncharacterized effects on host physiology. Here, we used reverse-phase liquid chromatography-coupled tandem mass spectrometry to define the mouse intestinal proteome in the stomach, jejunum, ileum, cecum, and proximal colon under three colonization states: germ-free, monocolonized with Bacteroides thetaiotaomicron, and conventionally raised. Our analysis revealed distinct proteomic abundance profiles along the gastrointestinal tract. Unsupervised clustering showed that host protein abundance primarily depended on gastrointestinal location rather than colonization state and specific proteins and functions that defined these locations were identified by random forest classifications. K-means clustering of protein abundance across locations revealed substantial differences in host protein production between conventionally raised mice relative to germ-free and monocolonized mice. Finally, comparison to fecal proteomic datasets suggested that the identities of stool proteins are not biased to any region of the gastrointestinal tract, but are substantially impacted by the microbiota in the distal colon.
Project description:The mammalian gut harbors a diverse microbial community (gut microbiota) that mainly consists of bacteria. Their combined genomes (the microbiome) provide biochemical and metabolic functions that complement host physiology. Maintaining symbiosis seems to be a key requirement for health as dysbiosis is associated with the development of common diseases. Previous studies indicated that the microbiota and the hostM-bM-^@M-^Ys epithelium signal bidirectional inducing transcriptional responses to fine-tune and maintain symbiosis. However, little is known about the hostM-bM-^@M-^Ys responses to the microbiota along the length of the gut as earlier studies of gut microbial ecology mostly used either colonic or fecal samples. This is of importance as not only function and architecture of the gut varies along its length but also microbial distribution and diversity. Few recent studies have begun to investigate microbiota-induced host responses along the length of the gut. However, these reports used whole tissue samples and therefore do not allow drawing conclusions about specificity of the observed responses. Which cells in the intestinal tissue are responsible for the microbially induced response: epithelial, mesenchymal or immune cells? Where are the responding cells located? We used using extensive microarray analysis of laser capture microdissection (LCM) harvested ileal and colonic tip and crypt fractions from germ-free and conventionally-raised mice to investigate the microbiota-induced transcriptional responses in specific and well-defined cell populations of the hostM-bM-^@M-^Ys epithelium. Ileum and colon segments were dissected from germ-free and conventionally-raised 10-12 weeks old female C57Bl/6 mice, washed and frozen as OCT blocks. Cryosections were prepared from these OCT blocks and tip/crypt fractions isolated using laser capture microdissection. To investigate the microbiota-induced transcriptional responses specific for specific subpopulations of intestinal epithelial cells, tip and crypt fractions of ileal and colonic epithelium of germ-free and conventionally-raised 10-12 weeks old female C57Bl/6 mice were harvested using laser capture microdissection and probed in an extensive microarray analysis.
Project description:Objective: Roux-Y gastric bypass (RYGB) surgery is a last treatment resort to induce substantial and sustained weight loss in severe obesity. The anatomical rearrangement affects the intestinal microbiota but so far, little information is available how it interferes with microbial functionality and microbial-host interaction independent from weight loss. Design: A RYGB rat model was utilized and compared to sham-operated controls which were kept at matched body weight as RYGB animals by food restriction. We assessed microbial taxonomy by 16S rRNA gene sequencing and functional activity by metaproteomics and metabolomics on microbiota samples collected separately from the ileum, the cecum as well as the colon and separately analysed the lumen and mucus associated microbiota. Results: Altered gut architecture in RYGB strongly affected the occurrence of Actinobacteria, especially Bifidobacteriaceae and Proteobacteria which were increased, whereas Firmicutes were decreased, although Streptococcaceae and Clostridium perfringens were observed at higher abundances. A decrease of conjugated as well as secondary bile acids was observed in the RYGB-gut lumen. In addition the arginine biosynthesis pathway in the microbiota was altered, indicated by the changes in abundance of upstream metabolites and enzymes, resulting in lower levels of arginine and higher levels of aspartate in the colon after RYGB. Conclusion: The anatomical rearrangement in RYGB affects microbiota composition and functionality by changes in amino acid and bile acid metabolism, independent of weight loss. The shift in microbiota taxonomic structure after RYGB may be mediated by the resulting change in composition of the bile acid pool in the gut lumen.
Project description:Staphylococcus aureus is a common human and animal opportunistic pathogen. In humans nasal carriage of S. aureus is a risk factor for various infections. Methicillin-resistant S. aureus ST398 is highly prevalent in pigs in Europe and North America. The mechanism of successful pig colonization by MRSA ST398 is poorly understood. Previously, we developed a nasal colonization model of porcine nasal mucosa explants to identify molecular traits involved in nasal MRSA colonization of pigs. Here, we report the analysis of the transcriptome of MRSA ST398 strain S0462 during colonization on the explant epithelium. Major regulated genes were encoding metabolic processes and regulation of these genes represents metabolic adaptation to nasal mucosa explants. Colonization was not accompanied by significant changes in transcripts of main virulence associated genes or known human colonization factors. Here, we document regulation of two genes which have potential influence on S. aureus colonization; cysteine extracellular proteinase (scpA) and von Willebrand factor-binding protein (vwbp, located on SaPIbov5). Colonization with isogenic-deletion strains (Î?vwbp and Î?scpA) did not alter the nasal S. aureus colonization compared to wild type. Our results suggest that nasal colonization with MRSA ST398 is a complex event that is accompanied with changes in bacterial gene expression regulation and metabolic adaptation. Number of the samples: 5 (timepoint 0 min, 30 min, 60 min, 90 min and 180 min) in 4 replicates. 4 control samples
Project description:The goals of this study were to investigate whether two anesthesia regimens, with and without N2O, and bacterial colonization influence respiratory complications after major abdominal surgery for cancer.
Project description:Here we report that CCSCs themselves can sustain the maintenance of the primary human colorectal tumor and, through the activation of a functional EMT-program, drive the dissemination into the circulation and the colonization of distant organs.
Project description:Here we report that CCSCs themselves can sustain the maintenance of the primary human colorectal tumor and, through the activation of a functional EMT-program, drive the dissemination into the circulation and the colonization of distant organs.