Search results for "Wnt signaling"
showing 10 items of 118 documents
Polarity factor 'Frizzled' in the demosponge Suberites domuncula: identification, expression and localization of the receptor in the epithelium/pinac…
2003
Until recently, it was assumed that polarity and axis formation have evolved only in metazoan phyla higher than Cnidaria. One key molecule involved in the signal transduction causing tissue polarity is Frizzled, a seven-transmembrane receptor that is activated by the Wnt family of secreted proteins. We report the isolation and characterization of a Frizzled gene from the demosponge Suberites domuncula (Sd-Fz). The deduced polypeptide comprises all characteristic domains known from Frizzled receptors of higher metazoans. In situ hybridization studies show that Sd-Fz is expressed in cells close to the surface of the sponges and in the pinacocytes of some canals. Northern blot analysis demonst…
Isolation and characterization of Wnt pathway-related genes from Porifera.
2006
The Wnt signal acts by binding to Frizzled receptors, with the subsequent activation of two different signal transduction cascades, the canonical and the non-canonical Wnt pathways, involved in cell growth, differentiation, migration and fate. The canonical pathway functions through the translocation of beta-catenin to the nucleus and the activation of TCF/LEF transcription factors; it plays an important role in developmental patterning and cell fate decisions during embryogenesis. The non-canonical Wnt pathway is responsible for the planar cell polarity process in invertebrates, and for the convergent-extension movements during vertebrate gastrulation. The final effect of the non-canonical…
Regional and modular expression of morphogenetic factors in the demosponge Lubomirskia baicalensis
2008
Some sponges [phylum Porifera], e.g. the demosponges Lubomirskia baicalensis or Axinella polypoides, show an arborescent growth form. In the freshwater sponge L. baicalensis this morphotype is seen mostly in depths below 4 m while in more shallow regions it grows as a crust. The different growth forms are determined in nature very likely by water current and/or light. The branches of this species are composed of modules, arranged along the apical-basal axis. The modules are delimited by a precise architecture of the spicule bundles; longitudinal bundles originate from the apex of the earlier module, while at the basis of each module these bundles are cross-linked by traverse bundles under f…
RSPO2 gene rearrangement: a powerful driver of β-catenin activation in liver tumours
2019
ObjectiveWe aimed at the identification of genetic alterations that may functionally substitute for CTNNB1 mutation in ß-catenin-activated hepatocellular adenomas (HCAs) and hepatocellular carcinoma (HCC).DesignLarge cohorts of HCA (n=185) and HCC (n=468) were classified using immunohistochemistry. The mutational status of the CTNNB1 gene was determined in ß-catenin-activated HCA (b-HCA) and HCC with at least moderate nuclear CTNNB1 accumulation. Ultra-deep sequencing was used to characterise CTNNB1wild-type and ß-catenin-activated HCA and HCC. Expression profiling of HCA subtypes was performed.ResultsA roof plate-specific spondin 2 (RSPO2) gene rearrangement resulting from a 46.4 kb microd…
Lrp4, a Novel Receptor for Dickkopf 1 and Sclerostin, Is Expressed by Osteoblasts and Regulates Bone Growth and Turnover In Vivo
2009
Lrp4 is a multifunctional member of the low density lipoprotein-receptor gene family and a modulator of extracellular cell signaling pathways in development. For example, Lrp4 binds Wise, a secreted Wnt modulator and BMP antagonist. Lrp4 shares structural elements within the extracellular ligand binding domain with Lrp5 and Lrp6, two established Wnt co-receptors with important roles in osteogenesis. Sclerostin is a potent osteocyte secreted inhibitor of bone formation that directly binds Lrp5 and Lrp6 and modulates both BMP and Wnt signaling. The anti-osteogenic effect of sclerostin is thought to be mediated mainly by inhibition of Wnt signaling through Lrp5/6 within osteoblasts. Dickkopf1 …
Transcriptomic Signature of Trophoblast Differentiation in a Human Embryonic Stem Cell Model1
2011
Identification of genes involved in trophoblast differentiation is of great interest in understanding cellular and molecular mechanisms involved in placental development and is relevant clinically to fetal development, fertility, and maternal health. Herein, we investigated differentiation of human embryonic stem cells (hESCs) down the trophoblast lineage by culture with bone morphogenetic protein 4 (BMP4) over a 10-day period. Within 2 days, the stemness markers POU5F1 and NANOG were markedly down-regulated, followed temporally by up-regulation of the CDX2, KRT7, HLA-G, ID2, CGA, and CGB trophoblast markers. To understand, on a global scale, changes in the transcriptome during the differen…
The Increase in Maternal Expression ofaxin1andaxin2Contribute to the Zebrafish MutantIchabodVentralized Phenotype
2015
β-catenin is a central effector of the Wnt pathway and one of the players in Ca+-dependent cell-cell adhesion. While many wnts are present and expressed in vertebrates, only one β-catenin exists in the majority of the organisms. One intriguing exception is zebrafish that carries two genes for β-catenin. The maternal recessive mutation ichabod presents very low levels of β-catenin2 that in turn affects dorsal axis formation, suggesting that β-catenin1 is incapable to compensate for β-catenin2 loss and raising the question of whether these two β-catenins may have differential roles during early axis specification. Here we identify a specific antibody that can discriminate selectively for β-ca…
Abstract 3354: Characterization of lung tumorspheres by gene expression and flow cytometry: differential expression in CSC-related markers and signal…
2016
Abstract Chemoresistance, progression and metastasis have made of lung cancer the first cause of cancer mortality. These features were linked to a subpopulation of cells, named cancer stem cells (CSCs), which remain largely unknown. The aim of this study was to isolate and characterize CSCs from lung cancer cell-lines and tumor-tissue from resectable non-small cell lung cancer (NSCLC). Methods: Tumor cells from resected NSCLC and cell lines (H1650, H1993, A549, and PC9) were grown in monolayer and as spheroids. RTqPCR was performed to analyze the mRNA expression of CSCs-related genes: CSC-markers (EPCAM1, ALDH1A1, CD166, ABCG2, CD44, CD133); pluripotency genes (KLF4, OCT4, NANOG, SOX2, MYC,…
Spontaneous tumour regression in keratoacanthomas is driven by Wnt/retinoic acid signalling cross-talk
2014
A fundamental goal in cancer biology is to identify the cells and signalling pathways that are keys to induce tumour regression. Here we use a spontaneously self-regressing tumour, cutaneous keratoacanthoma (KAs), to identify physiological mechanisms that drive tumour regression. By using a mouse model system that recapitulates the behaviour of human KAs, we show that self-regressing tumours shift their balance to a differentiation programme during regression. Furthermore, we demonstrate that developmental programs utilized for skin hair follicle regeneration, such as Wnt, are hijacked to sustain tumour growth and that the retinoic acid (RA) signalling pathway promotes tumour regression by …
Signalling codes for the maintenance and lineage commitment of embryonic gastric epithelial progenitors
2020
The identity of embryonic gastric epithelial progenitors is unknown. We used single-cell RNA sequencing, genetic lineage tracing and organoid assays to assess whether Axin2 and Lgr5 expressing cells are gastric progenitors in the developing mouse stomach. We show that Axin2+ cells represent a transient population of embryonic epithelial cells in the forestomach. Lgr5+ cells generate both glandular corpus and squamous forestomach organoids ex vivo. Only Lgr5+ progenitors give rise to zymogenic cells in culture. Modulating the activity of the WNT, BMP and Notch pathways in vivo and ex vivo, we found that WNTs are essential for the maintenance of Lgr5+ epithelial cells. Notch prevents differen…