Project description:We molecularly characterized thousands of intestinal cells including epithelial, masenchymal and immune cells using scRNAseq. This enable us to uncover the important role of villus tip telocytes as master regulators of the epithelial spatial expression programs along the villus axis
Project description:H3K79me2 ChIP-seq in mouse proximal intestinal Lgr5(hi) stem cells and villus cells Examination of H3K79me2 modifications between Lgr5(hi) stem cells and differentiated villus cells
Project description:The protective and absorptive functions of the intestinal epithelium rely on differentiated enterocytes in the villi. The differentiation of enterocytes is orchestrated by sub-epithelial mesenchymal cells producing distinct ligands along the villus axis, in particular Bmps and Tgf. Here we show that individual Bmp ligands and Tgf drive distinct enterocytic programs specific to villus zonation. Bmp4 is expressed mainly from the centre to the upper part of the villus, and it activates preferentially genes connected to lipid uptake and metabolism. In contrast, Bmp2 is produced by villus-tip mesenchymal cells, and it influences the adhesive properties of villus-tip epithelial cells and the expression of antimicrobial peptides. Hence, Bmp2 promotes the terminal enterocytic differentiation at the villus-tip. Additionally, Tgf induces an epithelial gene expression programs similar to that triggered by Bmp2. The inhibition of Bmp receptor type I in vivo and using intestinal organoids lacking Smad4 revealed that Bmp2-driven villus-tip program is activated by a canonical Smad-dependent mechanism. Finally, we established an organoid cultivation system that enriches for villus-tip enterocytes and thereby better mimics the cellular composition of the intestinal epithelium. Altogether our data suggest that not only Bmp gradient, but also the activity of individual Bmp drives specific enterocytic programs.
Project description:Genes encoding transcription factors function as hubs in gene regulatory networks because they encode DNA-binding proteins, which bind to promoters that carry their binding sites. In the present work we have studied gene regulatory networks defined by genes with transcripts belonging to different mRNA abundance classes in the small intestinal epithelial cell. The focus is the rewiring that occurs in transcription factor hubs in these networks during the differentiation of the small intestinal epithelial cell while it migrates along the crypt-villus axis and during its development from a fetal endodermal cell to a mature adult villus epithelial cell. We have generated transcriptome data for mouse small intestinal villus, crypt and fetal intestinal epithelial cells. In addition we have generated metabolome data from crypt and villus cells. Our results show that the intestinal crypt transcription factor hubs that are rewired during differentiation are involved in the cell cycle process (E2F, NF-Y) and stem cell maintenance (c-Myc). In contrast the villi are dominated by a HNF-4 villus hub, which is rewired during differentiation by the addition of network genes with relevance for lipoprotein synthesis and lipid absorption. Moreover, we have identified a villus NF-kB hub, which was revealed by comparison of the villus and endoderm transcriptomes. The rewiring of the NF-kB villus hub during intestinal development reflects transcriptional activity established by host and microflora interactions. To aid in the mining of our results we have developed a web portal (http://gastro.imbg.ku.dk/mousecv/) allowing easy linkage between the transcriptomic data, biological processes and functions. Experiment Overall Design: Four different sample categories were analyzed. Experiment Overall Design: 1) Small intestinal crypts isolated form 12-weeks old C57BL/6 mice. These samples are in triplicates. Experiment Overall Design: 2) Small intestinal villi isolated form 12-weeks old C57BL/6 mice. These samples are in triplicates. Experiment Overall Design: 3) Embryonic day 12 mesenchyme. These samples are in quadruplicate. each sample is derived from a pool of mesenchymes (10-40) Experiment Overall Design: 4) Embryonic day 12 endoderm. These samples are in quadruplicate. each sample is derived from a pool of endoderms (10-40)
Project description:The identification of Lgr5 as an intestinal stem cell marker has made it possible to isolate and study primary stem cells from small intestine and skins. Applying genome-wide resequencing of bisulfite-treated genomic DNA, we profiled the DNA methylation changes of FACS-sorted Lgr5+ve stem cells and their immediate undifferentiated daughter cells from small intestine and skin. In addition to this, we also analyzed terminally differentiated villus cells. We find that terminal differentiation of an adult solid-tissue stem cell does not require DNA methylation dynamics at transcriptional start sites, but is characterized by hypo-methylation of enhancer-like domains. We used cell fractions of intestines from Lgr5-EGFP-ires-CreERT2 mice, expressing GFP under the control of the Lgr5 promoter. RNA was isolated from several FACS-sorted cell populations, one expressing GFP at high levels (GFPhi) and the other expressing GFP at low levels (GFPlow), both from small intestine and skin. We also isolated RNA from intestinal epithelial villus cells. Differentially labelled cRNA from GFPhi, GFPlow and villus cells from three different sorts (each combining three different mice) were hybridized on Affymetrix HT MG-430 PM arrays.
Project description:Genes encoding transcription factors function as hubs in gene regulatory networks because they encode DNA-binding proteins, which bind to promoters that carry their binding sites. In the present work we have studied gene regulatory networks defined by genes with transcripts belonging to different mRNA abundance classes in the small intestinal epithelial cell. The focus is the rewiring that occurs in transcription factor hubs in these networks during the differentiation of the small intestinal epithelial cell while it migrates along the crypt-villus axis and during its development from a fetal endodermal cell to a mature adult villus epithelial cell. We have generated transcriptome data for mouse small intestinal villus, crypt and fetal intestinal epithelial cells. In addition we have generated metabolome data from crypt and villus cells. Our results show that the intestinal crypt transcription factor hubs that are rewired during differentiation are involved in the cell cycle process (E2F, NF-Y) and stem cell maintenance (c-Myc). In contrast the villi are dominated by a HNF-4 villus hub, which is rewired during differentiation by the addition of network genes with relevance for lipoprotein synthesis and lipid absorption. Moreover, we have identified a villus NF-kB hub, which was revealed by comparison of the villus and endoderm transcriptomes. The rewiring of the NF-kB villus hub during intestinal development reflects transcriptional activity established by host and microflora interactions. To aid in the mining of our results we have developed a web portal (http://gastro.imbg.ku.dk/mousecv/) allowing easy linkage between the transcriptomic data, biological processes and functions. Keywords: Cell type comparison
Project description:The intestinal epithelium is the most rapidly self-renewing tissue in adult mammals. We have recently demonstrated the presence of approximately six cycling Lgr5+ stem cells at the bottoms of small intestinal crypts1. We have now established long-term culture conditions under which single crypts undergo multiple crypt fission events, whilst simultanously generating villus-like epithelial domains in which all differentiated cell types are present. Single sorted Lgr5+ stem cells can also initiate these crypt-villus organoids. Tracing experiments indicate that the Lgr5+ stem cell hierarchy is maintained in organoids. We conclude that intestinal crypt-villus units are self-organizing structures, which can be built from a single stem cell in the absence of a non-epithelial cellular niche. Keywords: expression profiling