Project description:In murine models, we find that irradiation of Paneth cells caused a gain of a stem cell-like transcriptome and induced activation of the Notch signaling pathway. This study documents plasticity by Paneth cells, a fully committed cell population to participate in epithelial replenishment following stem cell loss.
Project description:The Notch signalling pathway plays fundamental roles in diverse developmental processes in metazoans, where it is important in driving cell fate and directing differentiation of various cell types. However, we still have limited knowledge about the role of Notch in early preimplantation stages of mammalian development, or how it interacts with other signalling pathways active at these stages such as Hippo. By using genetic and pharmacological tools in vivo, together with image analysis of single embryos and pluripotent cell culture, we have found that Notch is active from the 4-cell stage. Transcriptomic analysis in single morula identified novel Notch targets, such as early naïve pluripotency markers or transcriptional repressors such as TLE4. Our results reveal a previously undescribed role for Notch in driving transitions during the gradual loss of potency that takes place in the early mouse embryo prior to the first lineage decisions.
Project description:Homeostasis of self-renewing small intestinal crypts results from neutral competition between Lgr5 stem cells, small cycling cells located at crypt bottoms1, 2. Lgr5 stem cells are interspersed between terminally differentiated Paneth cells, that are known to produce bactericidal products such as lysozyme and cryptdins/defensins3. Single Lgr5-expressing stem cells can be cultured to form long-lived, self-organizing crypt-villus organoids in the absence of non-epithelial niche cells4. Here, we note a close physical association of Lgr5 stem cells with Paneth cells in vivo and in vitro. CD24+ Paneth cells express EGF, TGFα, Wnt3 and the Notch-ligand Dll4, all essential signals for stem cell maintenance in culture. Co-culturing of sorted stem cells with Paneth cells dramatically improves organoid formation. This Paneth cell requirement can be substituted by a pulse of exogenous Wnt. Genetic removal of Paneth cells in vivo results in the concomitant loss of Lgr5 stem cells. In colon crypts, CD24+ cells residing between Lgr5 stem cells may represent the Paneth cell equivalents. We conclude that Lgr5 stem cells compete for essential niche signals provided by a specialized daughter cell, the Paneth cell.
Project description:Paneth cells are a highly specialized population of intestinal epithelial cells located in the crypt adjacent to Lgr5+ stem cells, from which they differentiate through a process that requires downregulation of the Notch pathway. Their ability to store and release antimicrobial peptides protects the host from intestinal pathogens and controls intestinal inflammation. Here we show that PKCλ/ι is required for Paneth cell differentiation at the level of Atoh1 and Gfi1, through the control of EZH2 stability by direct phosphorylation. The selective inactivation of PKCλ/ι in epithelial cells results in the loss of mature Paneth cells, increased apoptosis and inflammation, and enhanced tumorigenesis. Importantly, PKCλ/ι expression in human Paneth cells decreases with progression of Crohn's disease. Kaplan-Meier survival analysis of CRC patients revealed that low PRKCI levels correlated with significantly worse patient survival. Therefore, PKCλ/ι is a negative regulator of intestinal inflammation and cancer through its role in Paneth cell homeostasis.
Project description:Homeostasis of self-renewing small intestinal crypts results from neutral competition between Lgr5 stem cells, small cycling cells located at crypt bottoms1, 2. Lgr5 stem cells are interspersed between terminally differentiated Paneth cells, that are known to produce bactericidal products such as lysozyme and cryptdins/defensins3. Single Lgr5-expressing stem cells can be cultured to form long-lived, self-organizing crypt-villus organoids in the absence of non-epithelial niche cells4. Here, we note a close physical association of Lgr5 stem cells with Paneth cells in vivo and in vitro. CD24+ Paneth cells express EGF, TGF?, Wnt3 and the Notch-ligand Dll4, all essential signals for stem cell maintenance in culture. Co-culturing of sorted stem cells with Paneth cells dramatically improves organoid formation. This Paneth cell requirement can be substituted by a pulse of exogenous Wnt. Genetic removal of Paneth cells in vivo results in the concomitant loss of Lgr5 stem cells. In colon crypts, CD24+ cells residing between Lgr5 stem cells may represent the Paneth cell equivalents. We conclude that Lgr5 stem cells compete for essential niche signals provided by a specialized daughter cell, the Paneth cell. We used intestinal cell fractions from Lgr5-EGFP-ires-CreERT2 mice, expressing GFP under the control of the Lgr5 promoter. RNA was isolated from two FACS sorted cell populations: stem cells were sorted based on high level of GFP expression (GFPhi) and Paneth cells were sorted based on high level of CD24 expression (CD24hi) and high side-scatter (SSChi). Differentially labelled cRNA from GFPhi and CD24hi/SSChi cells from two different sorts (each combining ten individual mice) were hybridized on 4X44K Agilent Whole Mouse Genome dual colour Microarrays (G4122F) in two dye swap experiments, resulting in four individual arrays.
Project description:Paneth cells are important for maintaining epithelial cell renewal and modulating innate immune function in the intestine through secretion of growth factors and antimicrobial peptides, which help sustain epithelial stem and progenitor cells and contribute to the intestinal barrier and protection against pathogenic bacteria. Here we show that the intestine-enriched miR-802 is a central regulator of intestinal epithelial cell proliferation and Paneth cell function. Genetic ablation of mir-802 in mice leads to amplified ROS generation and Notch/Wnt signaling, increased intestinal epithelial turnover, impaired enterocyte differentiation and nutrient uptake, and increased enterocyte apoptosis. Mice lacking mir-802 in the intestine also exhibit Paneth cell expansion, increased antimicrobial peptide production, and protection against Salmonella infection. This phenotype relies on the miR-802 target gene Tmed9.
Project description:The impact of removal of Mll1 in intestinal Paneth cells expressing an constitutively active form of beta-catenin (beta-cateninGOF) was analysed in 4 pairs of sorted Paneth cells of Lgr5-CreERT2; beta-cateninGOF;Mll1+/- (control) and Lgr5-CreERT2; beta-cateninGOF;Mll1-/- (knockout) mice at 10 days after tamoxifen-induced mutagenesis. Using 75-base-pair reads, around 30 million reads per sample with comparable unique mapped reads (52-93%) were obtained. To analyze differentially expressed genes, we applied DESeq2 analysis to the RNA-seq dataset. Differentially expressed genes in beta-cateninGOF; Mll1-/- versus beta-cateninGOF; Mll1+/- Paneth cells showed both up- and downregulation of genes at a false discovery rate (FDR) of 10%. This included a global increase in the expression of goblet cell-specific genes. Downregulated genes included specific markers of Paneth cells, indicating that ablation of Mll1 in Paneth cells shifted their identity towards a mixed Paneth-goblet cell fate.
Project description:The single cell level Paneth cell transcriptome under gnotobiotic condition has not been resolved. How gut microbiome modulates Paneth cell transcriptome at single cell level in germ-free mice was not known. We used a flow cytometry method to isolate highly pure ileal Paneth cells from germ free (GF) Paneth cell reporter mice (Lyz1-3'UTR-IRES-CreER) and from exGF Paneth cell reporter mice that were transplanted with wild type C57B/l6 mouse gut microbiota (exGF+B6M). These isolated Paneth cells were subjected to single cell RNA sequencing by 10xGenomics.
Project description:BACKGROUND & AIMS: Stems cells within the intestinal epithelium generate daughter cells which undergo lineage commitment and maturation through the concerted action of the Wnt and Notch signalling cascades. Both pathways, in turn, regulate transcription factor networks which further define differentiation towards either enterocytes or one of three secretory cell lineages (Paneth, goblet or enteroendocrine cells). In this manuscript, we identified the Ets domain transcription factor, Spdef, as a novel lineage maker of goblet and Paneth cells. METHODS: To address the function of Spdef in vivo, we inactivated the Spdef gene and analysed the intestinal phenotype using a range of histological techniques and DNA microarray profiling. RESULTS: In accordance with the expression data we found that loss of Spdef severely impaired the maturation of goblet and Paneth cells and conversely lead to an accumulation of immature secretory progenitors. Moreover, we provide evidence suggesting that Spdef positively and negatively regulates a specific subset of goblet and Paneth cell genes including Cryptdins, Mmp7, Ang4, Kallikreins, and Muc2. CONCLUSION: We propose a model whereby Spdef acts downstream of Math1 to promote terminal differentiation of a secretory progenitor pool towards Paneth and goblet cells. Keywords: expression profiling