Project description:Krüppel-like factor 9 (Klf9), a zinc-finger transcription factor, is implicated in the control of cell proliferation, cell differentiation and cell fate in brain and uterus. Using Klf9 null mutant mice, we have investigated the involvement of Klf9 in small intestine crypt-villus cell renewal and lineage determination. We report the predominant expression of Klf9 gene in small intestine smooth muscle (muscularis externa). Jejunums null for Klf9 have shorter villi, reduced crypt stem/transit cell proliferation, and altered lineage determination as indicated by decreased and increased numbers of Goblet and Paneth cells, respectively. A stimulatory role for Klf9 in villus cell migration was demonstrated by BrdU labeling. Results suggest that Klf9 controls the elaboration, from small intestine smooth muscle, of molecular mediator(s) of crypt cell proliferation and lineage determination, and of villus cell migration. Keywords: Genetic modification
Project description:Kruppel-like factor 9 (Klf9), a zinc-finger transcription factor, is implicated in the control of cell proliferation, cell differentiation and cell fate in brain and uterus. Using Klf9 null mutant mice, we have investigated the involvement of Klf9 in small intestine crypt-villus cell renewal and lineage determination. We report the predominant expression of Klf9 gene in small intestine smooth muscle (muscularis externa). Jejunums null for Klf9 have shorter villi, reduced crypt stem/transit cell proliferation, and altered lineage determination as indicated by decreased and increased numbers of Goblet and Paneth cells, respectively. A stimulatory role for Klf9 in villus cell migration was demonstrated by BrdU labeling. Results suggest that Klf9 controls the elaboration, from small intestine smooth muscle, of molecular mediator(s) of crypt cell proliferation and lineage determination, and of villus cell migration. Experiment Overall Design: Total RNA was extracted in parallel from the jejunums of five WT and five Klf9-/- male mice (PND 30) using TRIzol reagent (Invitrogen, Carlsbad, CA). Conversion of each RNA preparation to corresponding fragmented cRNA. Fifteen ug of each cRNA was hybridized for 16 hours to an Affymetrix mouse 430A GeneChip. Ten GeneChips (each corresponding to a single animal) were hybridized, washed and scanned in parallel. Following the wash, signal amplification, and signal detection steps, GeneChips were scanned (Agilent GeneArray laser scanner) and the resultant images quantified using Affymetrix MAS 5.0 software.
Project description:We developed a compartmental model of the small intestinal epithelium that describes stem and progenitor cell proliferation and differentiation and cell migration onto the villus. The model includes a negative feedback loop from villus cells to regulate crypt proliferation and integrates heterogeneous epithelial-related processes, such as the transcriptional profile, citrulline kinetics and probability of diarrhea.
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
Project description:Mice lacking 3-hydroxy-3-methylglutaryl-coenzyme A reductase (Hmgcr) in intestinal villus and crypt epithelial cells were generated using a Villin-Cre transgene. Label free proteome profiling was measure for Wild type and KO mouse.
Project description:The small intestinal crypt exhibits a defined spatial organisation involving multiple cell types that undergo continuous proliferation and differentiation while migrating towards the villus. We have built a multi-scale agent-based model (ABM), with individual cells interacting in the crypt geometry, which reproduces the self-organizing stable behaviour reported for the crypt. In our ABM, spatial organization emerges from the dynamic interaction of multiple signalling pathways, which include the Wnt, Notch, BMP and RNF43/ZNRF3 pathways that orchestrate cellular fate and mechanisms of contact inhibition of proliferation as well as feedback loops that regulate the expansion of the niche and size of the crypt. Moreover, this dynamic signalling network interacts with the main cell cycle proteins, governing the progression of each cell across the division stages.
Project description:Intestinal stem cells (ISCs) at the crypt base divide and give rise to progenitor cells that have the capacity to proliferate and differentiate into various mature epithelial cell types in the transit-amplifying (TA) zone. Here, we identified the transcription factor ARID3A as a novel regulator of intestinal epithelial cell proliferation and differentiation at the TA compartment. We show that ARID3A forms an expression gradient from villus tip to the early progenitors at the crypts mediated by TGF-β and WNT signalling. Intestinal epithelial-specific deletion of Arid3a reduces proliferation of TA cells. Bulk and single cell transcriptomic analysis shows increased enterocyte differentiation and reduced secretory cells in the Arid3a cKO intestine. Interestingly, upper-villus gene signatures of both enterocytes and secretory cells are enriched in the mutant intestine. We find that the enhanced enterocyte differentiation in the Arid3a cKO intestine is caused by increased binding of HNF1 and HNF4. Finally, we show that loss of Arid3a impairs irradiation-induced regenerative process by altering the dynamics of proliferation and apoptosis. Our findings imply that ARID3A may play a gatekeeping role in the TA compartment to maintain the “just-right” proliferation-to-differentiation ratio for tissue homeostasis and plasticity
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 Freshly isolated small intestinal crypts from two mice were divided into two parts. RNA was directly isolated from one part (RNeasy Mini Kit, Qiagen), the other part was cultured for one week according to the conditions described in the associated paper, followed by RNA isolation. We prepared labeled cRNA following the manufacturer’s instruction (Agilent Technologies). Differentially labelled cRNA from small intestinal crypts and organoids were hybridised separately for the two mice on a 4X44k Agilent Whole Mouse Genome dual colour Microarrays (G4122F) in two dye swap experiments, resulting in four individual 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