Lgr4 is required for Paneth cell differentiation and maintenance of intestinal stem cells
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ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Frederick Libert
PROVIDER: E-GEOD-27904 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Gene inactivation of the orphan G protein-coupled receptor Lgr4, a paralog of the epithelial stem cell marker Lgr5, results in 50% decrease of epithelial cell proliferation and 80% reduction in terminal differentiation of Paneth cells in postnatal mouse intestinal crypts. When cultured ex vivo, Lgr4-deficient crypts or progenitors, but not Lgr5-deficient progenitors, die rapidly with dramatic downregulation of stem cell markers and Wnt target genes, including Lgr5. Partial rescue of this phenotype is achieved by LiCl addition to the culture medium, but not by Wnt agonists. Our results identify Lgr4 as a permissive factor of the Wnt pathway in the intestine and, as such, as a potential target for intestinal cancer therapy.
2012-03-10 | GSE27904 | GEO
Project description:The transactivation of TCF target genes induced by Wnt pathway mutations constitutes the primary transforming event in colorectal cancer (CRC). We show that disruption of beta-catenin/TCF-4 activity in CRC cells induces a rapid G1 arrest and blocks a genetic program that is physiologically active in the proliferative compartment of colon crypts. Coincidently, an intestinal differentiation program is induced. The TCF-4 target gene c-MYC plays a central role in this switch by direct repression of the p21(CIP1/WAF1) promoter. Following disruption of beta-catenin/TCF-4 activity, the decreased expression of c-MYC releases p21(CIP1/WAF1) transcription, which in turn mediates G1 arrest and differentiation. Thus, the beta-catenin/TCF-4 complex constitutes the master switch that controls proliferation versus differentiation in healthy and malignant intestinal epithelial cells. Groups of assays that are related as part of a time series. Computed
2005-09-10 | E-GEOD-3282 | biostudies-arrayexpress
Project description:The adult stem cell marker Lgr5 and its close relative Lgr4 are often co-expressed in Wnt-driven proliferative compartments. Conditional deletion of the two genes in the gut impairs expression of Wnt target genes and results in rapid demise of intestinal crypts, thus phenocopying the effects of Wnt pathway inhibition. By mass-spectrometry, we find that Lgr4 and Lgr5 associate with the endogenous Wnt co-receptors Frizzled-5/7 and Lrp5/6 in HEK293 cells and in colorectal cancer cells. We also find that soluble Rspondin1, a Wnt pathway agonist, specifically binds to endogenous Lgr4 on HEK293 cells. In these cells, soluble Rspondin1 potently enhances canonical Wnt signals initiated by Wnt3A. Removal of Lgr4 does not affect Wnt3A-induced signals, but abrogates the Rspondin1-mediated enhancement of these signals, a phenomenon rescued by re-expression of Lgr4, -5 or -6. Rspondin1 and can be rescued by Wnt pathway activation. Lgr4/5/6 are facultative Wnt receptor components that mediate Wnt signal enhancement by soluble Rspondin proteins. We used two different experimental setups to show that concomitant deletion of Lgr4 and Lgr5 affects the expression of Wnt pathway target genes. First, we determined the downregulated genes after Lgr4/5 deletion in AhCre_Lgr4fl/fl_Lgr5 fl/fl mice on day 1 post-deletion, before any histological changes are apparent in these mice (Lgr4/5 gene signature). Next, we acutely withheld the Wnt agonist Rspondin1 from in vitro crypt organoid cultures and performed differential gene expression before, and 1 day after withdrawal (Rspondin1 withdrawal signature). For better comparison we also deleted the Lgr4 and Lgr5 in vitro in organoids isolated from VillinCre_Lgr4fl/fl_Lgr5 fl/fl mice, and performed microarrays 1 day after deletion in vitro. Furthermore, we used published expression data from Apcfl/fl mice (Apc deletion signature). Deletion of Apc results in the immediate upregulation of Wnt pathway target genes. Comparison of the Lgr4/5 gene signature to both the Rspondin1 withdrawal signature and the Apc deletion signatures using Gene Set Enrichment Analysis (GSEA) showed that the genes deregulated after simultaneous deletion of Lgr4 and -5 are in the majority under the control of the Wnt pathway.
2011-07-04 | E-GEOD-28265 | biostudies-arrayexpress
Project description:The adult stem cell marker Lgr5 and its close relative Lgr4 are often co-expressed in Wnt-driven proliferative compartments. Conditional deletion of the two genes in the gut impairs expression of Wnt target genes and results in rapid demise of intestinal crypts, thus phenocopying the effects of Wnt pathway inhibition. By mass-spectrometry, we find that Lgr4 and Lgr5 associate with the endogenous Wnt co-receptors Frizzled-5/7 and Lrp5/6 in HEK293 cells and in colorectal cancer cells. We also find that soluble Rspondin1, a Wnt pathway agonist, specifically binds to endogenous Lgr4 on HEK293 cells. In these cells, soluble Rspondin1 potently enhances canonical Wnt signals initiated by Wnt3A. Removal of Lgr4 does not affect Wnt3A-induced signals, but abrogates the Rspondin1-mediated enhancement of these signals, a phenomenon rescued by re-expression of Lgr4, -5 or -6. Rspondin1 and can be rescued by Wnt pathway activation. Lgr4/5/6 are facultative Wnt receptor components that mediate Wnt signal enhancement by soluble Rspondin proteins.
2011-07-04 | GSE28265 | GEO
Project description:Background: Gene expression profiling of breast carcinomas has increased our understanding of the heterogeneous biology of this disease and promises to impact clinical care. The aim of this study was to evaluate the prognostic value of gene expression-based classification along with established prognostic markers and mutation status of the TP53 gene, in a group of breast cancer patients with long-term (12-16 years) follow-up. Methods: The clinical and histopathological parameters of 200 breast cancer patients were studied for their effects on clinical outcome using univariate/multivariate Cox regression. The prognostic impact of mutations in the TP53 gene, identified using TTGE and sequencing, was also evaluated. Eighty of the samples were analyzed for gene expression using 42K cDNA microarrays and the patients were assigned to five previously defined molecular expression groups. The strength of the gene expression based classification versus standard markers was evaluated by adding this variable to the Cox regression model used to analyze all samples. Results: Both univariate and multivariate analysis showed that TP53 mutation status, tumor size and lymph node status were the strongest predictors of breast cancer survival for the whole group of patients. Analyses of the patients with gene expression data showed that TP53 mutation status, gene expression based classification, tumor size and lymph node status were significant predictors of survival. The TP53 mutation status showed strong association with the ?basal-like? and ?ERBB2+? gene expression subgroups, and tumors with mutation had a characteristic gene expression pattern. Conclusions: TP53 mutation status and gene-expression based groups are important survival markers of breast cancer, and these molecular markers may provide prognostic information that complements clinical variables. The study adds experience and knowledge to an ongoing characterization and classification of the disease. Experiment set consisting of 80 primary breast carcinomas collected at Ulleval University Hospital (ULL-samples), Oslo, Norway from 1990-94, and one normal sample from breast reduction surgery.
2012-09-18 | E-GEOD-40954 | biostudies-arrayexpress
Project description:In 15 patients with rheumatoid arthritis the baseline expression (t=0) of type I IFN-regulated genes was determined in peripheral blood cells (PAXgene) using cDNA-microarrays and compared to levels one month after (t=1) anti-TNF treatment (infliximab). Therefore, we used 43K cDNA microarrays from the Stanford Functional Genomics Facility (http://microarray.org/sfgf/) printed on aminosilane-coated slides containing ~20.000 unique genes. Only one batch of arrays was used for all experiments. First DNA spots were UV-cross linked to the slide using 150-300 mJoules. Sample preparation and microarray hybridization were performed as described previously (1,2). Data storage and filtering was performed using the Stanford Microarray Database (http://genome-www5.stanford.edu//) as described previously. 1. van der Pouw Kraan TC, Wijbrandts CA, van Baarsen LG, Voskuyl AE, Rustenburg F, Baggen JM et al.: Rheumatoid arthritis subtypes identified by genomic profiling of peripheral blood cells: assignment of a type I interferon signature in a subpopulation of patients. Ann Rheum Dis 2007, 66: 1008-1014. 2. van der Pouw Kraan TC, van Baarsen LG, Rustenburg F, Baltus B, Fero M, Verweij CL: Gene expression profiling in rheumatology. Methods Mol Med 2007, 136: 305-327. Abbreviations: - Bnrs are the different patients analyzed - PAX or Paxgene indicates the total RNA was isolated from peripheral blood obtained in PAXgene tubes - CRS: common reference sample: We made a common reference that consisted of a mixture of mRNAs isolated from 11 different cell lines (Perou CM, Jeffrey SS, van de RM et al. Distinctive gene expression patterns in human mammary epithelial cells and breast cancers. Proc Natl Acad Sci U S A. 1999; 96:9212-9217) supplemented with RNA from rheumatoid synovial tissue, fibroblasts, and activated peripheral blood mononuclear cells (PBMCs). - PMT: photomultiplier tube: the sensitivity/intensity of the scanner can be adjusted to prevent spot saturation. Compound Based Treatment: anti-TNF (infliximab) reference_design
2010-06-24 | E-GEOD-19821 | biostudies-arrayexpress
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.
2009-04-03 | E-GEOD-14594 | biostudies-arrayexpress
Project description:M. tuberculosis strain 1254 wild type (WT) and its isogenic delta Rv3662c-Rv3665c KO (opp KO) and complemented opp::opp were cultured in vitro, in liquid 7H9 media supplemented with OADC and 0.05% Tween 80, 0.5% glycerol, in a 150 mL volume, contained in roller bottles, incubated at 37oC. Growth was monitored as OD600 nm and recorded on a daily basis. In all experiments, the starting OD600 nm was 0.04-0.05. Aliquots were removed at each OD600 nm to make serial dilutions, plate onto 7H10 OADC agar plates for CFU counts. When cells reached OD600 nm of 0.3, 1.0, and 1.5, a 10-30 mL aliquot was taken, centrifuged 3 min at 3000 g, at room temperature, and the supernatant was discarded, with cell pellets being immediately frozen by inclusion into dry ice. Frozen cell pellets were stored at -80oC for later RNA isolation. In all experiments, RNA from WT was labeled with Cy5, and RNA from the opp KO was labeled with Cy3. In all experiments, the microarray comparsion used RNA from cells of the same growth stage, i.e., WT OD 0.3 vs opp KO OD 0.3, WT OD 1.0 vs opp KO OD 1.0, and WT OD 1.5 vs opp KO OD 1.5. When comparing the Complemented opp::opp vs the mutant opp KO, RNA from the later strain was Cy3-labeled. A cell type comparison design experiment design type compares cells of different type for example different cell lines. cell_type_comparison_design
2009-10-06 | E-GEOD-18426 | biostudies-arrayexpress
Project description:The accompanying dataset is the result of a systematic study to identify the RNA cargoes associated with the cytoskeletal motor proteins of Saccharomyces cerevisiae. We immunopurified, via the use of integrated, C-terminal GFP and 9Myc tags, the five actomyosin motors, Myo1, Myo2, Myo3, Myo4, and Myo5; the kinesin-like proteins Kar3, Kip1, Kip2, Kip3, and Smy1; and the dynein, Dyn1, from S. cerevisiae. Cells were either treated with formaldehyde or with the small molecule latrunculin B. We used formaldehyde crosslinking to stabilize associations between motors proteins and interacting RNAs before IP. Yeast cells growing exponentially in rich medium were treated with formaldehyde, lysed and sonicated, then incubated with magnetic beads coupled to monoclonal antibodies against either 9Myc or GFP to isolate the tagged motor proteins along with any associated RNAs. After IP, the formaldehyde crosslinks were reversed and the enriched RNAs and RNAs purified from the corresponding total lysate were amplified and labeled respectively with Cy5 and Cy3, then jointly hybridized to custom-made, S. cerevisiae oligonucleotide microarrays (Hogan et al., PLoS Biology, 2008). Alternatively, the addition of a low concentration of latrunculin B (2 ug/ml) to live cells to partially solubilize the actin cytoskeleton allowed for successful IP of the motor proteins and associated mRNAs without the need for a chemical crosslinker. In both the case of latrunculin B and formaldehyde treatment, we also performed IPs in which the untagged parent yeast strains were processed for IP and microarray analysis in a manner identical to that of the tagged strains (labeled as mock). transcription profiling
2012-01-27 | E-GEOD-35343 | biostudies-arrayexpress
Project description:Background: Conflicting results have been reported about the role of the two-component sensor and transcriptional regulator DosS/DosR, controlling the expression of the dormancy DosR regulon, for in vivo virulence of M. tuberculosis. Here, we have used a new approach to further analyze the relevance of the dosRS system, by driving DosR (Rv3133c) expression under the control of a constitutive promoter (phsp60). Methodology/Principal Findings: M. tuberculosis H37Rv constitutively expressing the transcriptional regulator DosR (Mtb::DosR) was compared to wild type M. tuberculosis (Mtb+/+) for in vitro growth kinetics and expression of the target genes of the DosR dormancy regulon, for in vivo virulence and for immunogenicity in mice. Under aerobic conditions, hsp60-driven DosR induced the expression of 28 out of 39 tested DosR regulon genes. In vitro growth characteristics were comparable for both strains, but Mtb::DosR showed an attenuated in vivo phenotype in immunocompetent mice, as indicated by reduced bacterial replication, reduced pulmonary immunopathology, reduced cachexia and significantly prolonged survival time as compared Mtb+/+. In immunodeficient SCID mice, Mtb::DosR was fully virulent. RT-qPCR analysis revealed a strong and comparable pulmonary TNF-?? and IL-23 expression following intratracheal infection, whereas IL-12 and IL-17 expression was slightly higher with wild type Mtb+/+. Finally, mice persistently infected with Mtb::DosR for 8 months showed five to tenfold higher lung IFN-?? responses against ten of the 48 DosR regulon encoded antigens (Rv1733c, Rv1734, Rv1738, Rv1996, Rv1997, Rv2029c, Rv2623, Rv2627c, Rv2628 and Rv3127) than mice actively infected with Mtb+/+. In spleen however, DosR regulon encoded antigen specific IFN-?? responses were similar in both groups. Conclusions/Significance. Collectively, these results suggest that increased DosR regulon encoded antigen specific pulmonary T cell responses are responsible for the attenuated phenotype of Mtb::DosR and that infection with Mtb::DosR could be used as a new animal model for studying key aspects of latent tuberculosis. Set of arrays that are part of repeated experiments
2012-06-12 | E-GEOD-19838 | biostudies-arrayexpress