Project description:The chicken gastrointestinal tract (GIT) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided. T) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided.
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 Runx1 transcription factor plays an important role in tissue homeostasis through its effects on stem/progenitor cell populations and differentiation. The effect of Runx1 on epithelial differentiation of the secretory cell lineage of the colon was recently demonstrated. This study aimed to examine the role of Runx1 in tumor development in epithelial cells of the gastrointestinal tract. Conditional knockout mice were generated that lacked Runx1 expression in epithelial cells of the GI tract. These mice were crossed onto the ApcMin background, sacrificed, and their intestinal tumor phenotypes were compared with ApcMin Runx1 wildtype control mice. Apc-wildtype Runx1-mutant mice were also examined for tumor development. Colons from Runx1 knockout and wildtype mice were used for genome-wide mRNA expression analyses followed by gene-specific quantitative RT-PCR of whole colon and colon epithelium, to identify Runx1 target genes. Runx1 deficiency in intestinal epithelial cells significantly enhanced tumorigenesis in ApcMin mice. Notably, epithelial Runx1 deficiency in Apc-wildtype mice was sufficient to cause tumor development. Absence of Runx1 was associated with global changes in expression of genes involved in inflammation and intestinal metabolism, and with gene sets indicative of metastatic phenotype and poor prognosis. Gene-specific analysis of Runx1 deficient colon epithelium revealed increased expression of genes linked to an expansion of the stem/progenitor cell population. These results identify Runx1 as a novel tumor suppressor gene for gastrointestinal tumors and support a role for Runx1 in maintaining the balance between the intestinal stem/progenitor cell population and epithelial differentiation of the GI tract. A total of 8 colon tissue RNA samples were analyzed, comprising 4 colon samples from wild-type mice (Villin-Cre negative / Runx1-floxed) and 4 colon samples from mice that lack epithelial expression of Runx1 (Villin-Cre positive/Runx1-floxed).
Project description:The Runx1 transcription factor plays an important role in tissue homeostasis through its effects on stem/progenitor cell populations and differentiation. The effect of Runx1 on epithelial differentiation of the secretory cell lineage of the colon was recently demonstrated. This study aimed to examine the role of Runx1 in tumor development in epithelial cells of the gastrointestinal tract. Conditional knockout mice were generated that lacked Runx1 expression in epithelial cells of the GI tract. These mice were crossed onto the ApcMin background, sacrificed, and their intestinal tumor phenotypes were compared with ApcMin Runx1 wildtype control mice. Apc-wildtype Runx1-mutant mice were also examined for tumor development. Colons from Runx1 knockout and wildtype mice were used for genome-wide mRNA expression analyses followed by gene-specific quantitative RT-PCR of whole colon and colon epithelium, to identify Runx1 target genes. Runx1 deficiency in intestinal epithelial cells significantly enhanced tumorigenesis in ApcMin mice. Notably, epithelial Runx1 deficiency in Apc-wildtype mice was sufficient to cause tumor development. Absence of Runx1 was associated with global changes in expression of genes involved in inflammation and intestinal metabolism, and with gene sets indicative of metastatic phenotype and poor prognosis. Gene-specific analysis of Runx1 deficient colon epithelium revealed increased expression of genes linked to an expansion of the stem/progenitor cell population. These results identify Runx1 as a novel tumor suppressor gene for gastrointestinal tumors and support a role for Runx1 in maintaining the balance between the intestinal stem/progenitor cell population and epithelial differentiation of the GI tract.
Project description:The gastrointestinal tract is covered by a single layer of epithelial cells that, together with the mucus layers, protect the underlying tissue from bacterial invasion. The epithelium has one of the highest turnover rates in the body, renewing every 4-5 days. Using stable isotope labelling, high-resolution mass spectrometry and computational analysis, we report here a comprehensive dataset of the turnover rate of 3041 and the expression of 5012 intestinal epithelial cell proteins, analyzed under conventional and germ-free conditions across five different segments in mouse intestine. The median protein half-life was shorter in small intestine compared to colon, ranging from 3.5 to 4.2 days. Differences in protein turnover rates along the intestinal tract can be explained by distinct physiological functions and site-specific immune responses between the small and large intestine. Absence of microflora resulted in increased protein half-life by approximately one day.