Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA311937 | ENA |
REPOSITORIES: ENA
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Project description:The Wnt/ß-catenin pathway is orchestrating the development of the blood-brain barrier (BBB), but its downstream mediators have remained elusive. To identify potential effectors, we generated an endothelial cell specific Axin1 over-expressing mouse model, AOEiEC. We found that in AOEiE mice Wnt/ß-catenin signalling was down regulated leading to premature regression and remodelling without directly compromising BBB integrity. Interestingly, by comparing transcriptomes of endothelial cells from control and AOEiEC mice, we identified Adamtsl2 as a novel Wnt/ß-catenin-induced, secreted factor, important for stabilizing the cerebral vasculature during development. Importantly, loss-of-function and gain-of-function experiments revealed that Adamtsl2 alone was sufficient to rescue CNS vascular defects seen upon Wnt-signalling inhibition. Furthermore, using various cell and animal models we demonstrate that Adamtsl2 exerts its function by fine-tuning the TGFβ signalling pathway in CNS vessels. In conclusion, this study implicates Adamtsl2 as a mediator of Wnt/ß-catenin signalling during BBB development by linking it to TGFβ signalling.
2019-01-31 | GSE77874 | GEO
Project description:Context dependent molecular cues shape the formation of the cerebral vascular network and the function of the blood-brain barrier (BBB). The Wnt/ß-catenin pathway is orchestrating CNS vascular development, but downstream mediators have not been characterized. Here we generated an endothelial cell-specific R26-Axin1 overexpression (AOE) mouse model to inhibit Wnt/ß-catenin signaling. In AOE mice we discovered that blockade of Wnt/ß-catenin pathway leads to premature regression and remodeling without compromising BBB integrity. Importantly, by comparing transcriptomes of endothelial cells from wildtype and AOE mice, we identified ADAMTSL2 as a novel Wnt/ß-catenin-induced, secreted factor, important for stabilizing the BBB during development. Zebrafish loss-of-function and gain-of-function models, further demonstrated that ADAMTSL2 is crucial for normal vascular development and could rescue vascular phenotypes in AOE zebrafish brains. In conclusion, the studies presented here reveal a hitherto unrecognized role of ADAMTSL2 as an endothelial cell-specific mediator of Wnt/ß-catenin signaling during CNS vascular development and BBB-formation.
2019-02-22 | GSE66848 | GEO
Project description:Rationale. The microvasculature of the central nervous system includes the blood-brain barrier (BBB), which regulates the permeability to nutrients and restricts the passage of toxic agents and inflammatory cells. Canonical Wnt/b-catenin signaling is responsible for the early phases of brain vascularization and blood-brain barrier differentiation. However, this signal declines after birth and other signaling pathways able to maintain barrier integrity at postnatal stage are still unknown. Objective. Sox17 constitutes a major downstream target of Wnt/b-catenin in endothelial cells and regulates arterial differentiation. In the present paper, we asked whether Sox17 may act downstream of Wnt/b-catenin in inducing BBB differentiation and maintenance. Methods and Results. Using reporter mice and nuclear staining of Sox17 and b-catenin, we report that while b-catenin signaling declines after birth, Sox17 activation increases and remains high in the adult. Endothelial-specific inactivation of Sox17 leads to increase of permeability of the brain microcirculation. The severity of this effect depends on the degree of BBB maturation: it is strong in the embryo, and progressively declines after birth. In search of Sox17 mechanism of action, RNA-Seq analysis of gene expression of brain endothelial cells has identified members of the Wnt/b-catenin signaling pathway as downstream targets of Sox17. Consistently, we found that Sox17 is a positive inducer of Wnt/b-catenin signaling and it acts in concert with this pathway to induce and maintain BBB properties. In vivo, inhibition of the b-catenin destruction complex or expression of a degradation-resistant b-catenin mutant, prevent the increase in permeability and retina vascular malformations observed in the absence of Sox17. Conclusions. Our data highlight a novel role for Sox17 in the induction and maintenance of the BBB and they underline the strict reciprocal tuning of this transcription factor and Wnt/b-catenin pathway. Modulation of Sox17 activity may be relevant to control BBB permeability in pathological conditions.
2019-02-12 | GSE122564 | GEO
Project description:Wnt signalling maintains the undifferentiated state of intestinal crypt/progenitor cells through the TCF4/ß-catenin activating transcriptional complex. In colorectal cancer, activating mutations in Wnt pathway components lead to inappropriate activation of the TCF4/ß-catenin transcriptional program and tumourigenesis in the gut epithelium. The mechanisms by which TCF4/ß-catenin activate key target genes are not well understood. Using a proteomics approach, we identified Tnik, a member of the Germinal centre kinase family, as a Tcf4 interactor in the proliferative crypts of mouse small intestine. Tnik is recruited to promoters of Wnt target genes in mouse crypts and in Ls174T colorectal cancer cells in a ß-catenin dependent manner. Depletion of TNIK and expression of TNIK kinase mutants abrogated TCF-LEF transcription, highlighting the essential role of the kinase activity in Wnt target gene activation. siRNA depletion of TNIK followed by expression array analysis demonstrated that TNIK is an essential and exclusive activator of Wnt induced transcriptional program. As an essential component in the TCF4/ß-catenin activator complex, the kinase TNIK may present an attractive candidate for drug targeting in colorectal cancer.
2009-08-13 | GSE17623 | GEO
Project description:Genetic and epigenetic defects in Wnt/ß-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/ß-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly de-repressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/ß-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/ß-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/ß-catenin signaling in colorectal cancer. Keywords: Colon cancer cell line
2008-03-29 | GSE10952 | GEO
Project description:24 colon normal and tumor pairs using Illumina BeadChip Human Ref8-v2. Genetic and epigenetic defects in Wnt/ß-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/ß-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly de-repressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/ß-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/ß-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/ß-catenin signaling in colorectal cancer. The clinical information for the colon tumor is not available. Keywords: human colon tumor
2008-03-29 | GSE10950 | GEO
Project description:Genetic and epigenetic defects in Wnt/?-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/ß-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly de-repressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/?-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/ß-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/ß-catenin signaling in colorectal cancer. This SuperSeries is composed of the SubSeries listed below.
2008-03-29 | GSE10972 | GEO
Project description:Canonical Wnt signaling output is mediated by β-catenin, which interacts with LEF/TCF transcription factors and recruits a general transcriptional activation complex to its C-terminus. Its N-terminus binds BCL9/9L proteins, which bind co-activators that in mammals contribute to fine-tuning the transcriptional output. We found that a BCL9/9L-dependent gene expression signature was strongly associated with patient outcome in colorectal cancer and that stem cell and mesenchymal genes determine its prognostic value. Abrogating BCL9/9L-β-catenin signaling in independent mouse colorectal cancer models resulted in virtual loss of these traits, and oncogenic intestinal organoids lacking BCL9/9L proteins proved no longer tumorigenic. Our findings suggest that the BCL9/9L arm of Wnt-β-catenin signaling sustains a stemness-to-differentiation equilibrium in colorectal cancer, which critically affects disease outcome. Mutational activation of the Wnt pathway is a key oncogenic event in colorectal cancer. Targeting the pathway downstream of activating mutations is challenging, and the therapeutic window is limited by intestinal toxicity. Contrasting with phenotypes caused by inactivating key Wnt pathway components, ablation of BCL9/9L proteins in adult mice indicated that they were dispensable for intestinal homeostasis, consistent with their role in tuning transcription. Cancer stem cells are increasingly recognized as responsible for tumor recurrence. The correlation between stemness traits in colorectal cancer models and BCL9/9L-β-catenin signaling suggests that high Wnt signaling output is required for their maintenance. Our findings suggest that pruning Wnt-β-catenin signaling might be well tolerated and prove sufficient for trimming stemness traits and improving disease outcome. Examination of Bcl9/9l-knockout versus wild-type transcriptome in murine AOM-DSS tumors, APC-Kras tumors and healthy colocyte extracts.
2015-11-08 | E-GEOD-60837 | biostudies-arrayexpress
Project description:ß-catenin is part of the cell-cell adhesion complex, where it plays a structural role but is also the key effector of the Wnt pathway, where it is endowed with a transcriptional regulatory activity. Oncogenic mutations of ß-catenin are present in about one third of hepatocellular carcinoma. In most tumors, ß-catenin mutations are heterozygous meaning that mutated and wild-type proteins co-exist in tumor cells. We address here the interplay between wild-type and mutated ß-catenins in liver tumor cells. We have designed a RNA interference strategy in HepG2 cells that allows uncoupling of the two functions of ß-catenin in the same cellular background: nuclear/transcriptional activity, a function almost exclusively mediated by the mutated ß-catenin, and membrane/structural activity, which is mediated by the degradable WT ß-catenin.
2021-01-22 | GSE144107 | GEO
Project description:Asymmetric signalling centres in the early embryo are essential for axis formation in vertebrates. These regions, namely the dorsal morula, yolk syncytial layer, and distal hypoblast/anterior visceral endoderm (in amphibians, teleosts and mammals, respectively), require the localised stabilisation of nuclear Beta-catenin (Ctnnb1), implying that localised Wnt/Beta-catenin signalling activity is critical in their establishment. However, it is becoming increasingly apparent that the stabilisation of Beta-catenin in this context may be initiated independently of secreted Wnt growth factor activity. In Xenopus, dorsal Beta-catenin stabilisation is initiated by a requisite microtubule-mediated symmetry-breaking event in the fertilised egg: “cortical rotation”. Vegetally-localised wnt11b mRNA has been implicated upstream of Beta-catenin in this context, as has the dorsal enrichment of Wnt ligand-independent activators of Beta-catenin, but the extent that each of these processes contribute to axis formation in this paradigm remains unclear. Here we describe a maternal effect mutation in Xenopus laevis wnt11b.L, generated by CRISPR mutagenesis. We demonstrate a maternal requirement for timely and complete gastrulation morphogenesis and a zygotic requirement for proper left-right asymmetry. We also show that a subset of maternal wnt11b mutants have axis and dorsal gene expression defects, and we find that microtubule assembly and cortical rotation are reduced in wnt11b mutant eggs, leading to less organised and directed vegetal microtubule arrays. mRNA sequencing was used to determine the extent of dorsal and other gene dysregulation during gastrulation.
2022-05-02 | GSE195806 | GEO