Project description:The intestinal epithelium is continuously regenerated by highly proliferative Lgr5+ intestinal stem cells (ISCs). The existence of a population of quiescent ISCs has been suggested yet its identity and features remain controversial. Here we describe that the expression of the RNA-binding protein Mex3a labels a subpopulation of Lgr5+ cells that divide less frequently and contribute to regenerate all intestinal lineages with slow kinetics. Single cell transcriptomic analysis revealed two classes of Lgr5-high cells, one of them defined by the Mex3a-expression program and by low levels of proliferation genes. Lineage tracing experiments show that large fraction of Mex3a+ cell population is continuously recalled into the rapidly dividing self-renewing ISC pool in homeostatic conditions. Chemotherapy and radiation target preferentially rapidly dividing Lgr5+ cells but spare the Mex3a-high/Lgr5+ population, which helps sustain the renewal of the intestinal epithelium during treatment.
Project description:The effort to better understand intestinal stem cell (ISC) identity and regulation remains a challenge. We have been studying the RNA-binding protein MEX3A as a putative ISC marker. In that context, we have generated the first Mex3a knockout (KO) mouse model and show MEX3A is crucial for maintenance of the Lgr5+ ISC pool. As part of a phenotypic characterization pipeline, we have performed transcriptomic profiling (RNA-sequencing) of isolated Mex3a KO small intestinal crypts and compared it against small intestinal crypts isolated from age-matched wild-type controls.
Project description:Transcriptomic data related to 4 different subpopulations found in Mex3a Ki/+ Lgr5 Gfp in APCflfl adenomas in untreated animals. Adenomas where induced with 3%DSS and a single shot of 8mg/kg of Tamoxifen. The populations are refered as Mex3a + Lgr5, Mex3a- Lgr5+ Mex3a+ Lgr5- and Mex3a- Lgr5- according to the flow cytometry profile. Cells were isolated using FACsARIA (BD)
Project description:In normal intestine, Lgr5 are a pool of rapidly dividing stem cells that gives rise to the whole intestinal crypts. Here we have labelled both Lgr5 and Ki67 genes with fluorescent markers by means of CRISPR/Cas9 in human patient derived organoids (PDO).
Project description:Mex3a labells a subpopulation of Cancer Stem cells defined by their slow proliferative behaviour. Nevertheless, the precise function of MEX3A is unknown, although it plays a role in chemoresistance. The Mex3a KO adenomas are less chemoresistant compared to their WT controls. We used microarrays to elucidate changes in gene expression in cells with the Mex3a promoter active (tomato expressing cells)
Project description:We previously identified Dclk1, a tuft cell marker, marks tumor stem cells (TSCs) in mouse intestinal tumors. In this study, we have identified IL17RB as a cell surface marker distinctively expressed by Dclk1+ tuft-like tumor cells in mouse intestinal tumors. Using this tuft cell marker, we compared and analyzed the transcriptome of Lgr5-tuft marker-, Lgr5+tuft marker-, Lgr5-tuft marker+, and Lgr5+tuft marker+ tumor cells. These analyses revealed that tuft-like tumor cells in the intestinal tumors comprise two distinct subsets: highly differentiated tuft-like tumor cells (Lgr5-tuft marker+ cells) and tuft-like tumor cells with TCS potential (Lgr5+tuft marker+ cells).
Project description:The purpose of this single cell experiment is to compare and characterize at molecular level actively cycling stem cells in the isthmus and quiescent stem cells in the base of the mouse stomach corpus. The lineage tracing data from Stmn1-CreERT2 shows that Stmn1+ cells in the corpus isthmus include fast dividing isthmus stem cells with long-term potency. On the other hand, chief cells including Lgr5+ subpopulation can play as quiescent stem cells in the base that are largely quiescent in homeostasis, but are activated upon injury. The isthmus stem cells and chief cells are isolated by Stmn1 and Pgc, respectively, and were subject to single cell RNA-seq experiment.
