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Sample records for canonical wnt signaling

  1. Both canonical and non-canonical Wnt signaling independently promote stem cell growth in mammospheres.

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    Alexander M Many

    Full Text Available The characterization of mammary stem cells, and signals that regulate their behavior, is of central importance in understanding developmental changes in the mammary gland and possibly for targeting stem-like cells in breast cancer. The canonical Wnt/β-catenin pathway is a signaling mechanism associated with maintenance of self-renewing stem cells in many tissues, including mammary epithelium, and can be oncogenic when deregulated. Wnt1 and Wnt3a are examples of ligands that activate the canonical pathway. Other Wnt ligands, such as Wnt5a, typically signal via non-canonical, β-catenin-independent, pathways that in some cases can antagonize canonical signaling. Since the role of non-canonical Wnt signaling in stem cell regulation is not well characterized, we set out to investigate this using mammosphere formation assays that reflect and quantify stem cell properties. Ex vivo mammosphere cultures were established from both wild-type and Wnt1 transgenic mice and were analyzed in response to manipulation of both canonical and non-canonical Wnt signaling. An increased level of mammosphere formation was observed in cultures derived from MMTV-Wnt1 versus wild-type animals, and this was blocked by treatment with Dkk1, a selective inhibitor of canonical Wnt signaling. Consistent with this, we found that a single dose of recombinant Wnt3a was sufficient to increase mammosphere formation in wild-type cultures. Surprisingly, we found that Wnt5a also increased mammosphere formation in these assays. We confirmed that this was not caused by an increase in canonical Wnt/β-catenin signaling but was instead mediated by non-canonical Wnt signals requiring the receptor tyrosine kinase Ror2 and activity of the Jun N-terminal kinase, JNK. We conclude that both canonical and non-canonical Wnt signals have positive effects promoting stem cell activity in mammosphere assays and that they do so via independent signaling mechanisms.

  2. Canonical Wnt signaling is necessary for object recognition memory consolidation.

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    Fortress, Ashley M; Schram, Sarah L; Tuscher, Jennifer J; Frick, Karyn M

    2013-07-31

    Wnt signaling has emerged as a potent regulator of hippocampal synaptic function, although no evidence yet supports a critical role for Wnt signaling in hippocampal memory. Here, we sought to determine whether canonical β-catenin-dependent Wnt signaling is necessary for hippocampal memory consolidation. Immediately after training in a hippocampal-dependent object recognition task, mice received a dorsal hippocampal (DH) infusion of vehicle or the canonical Wnt antagonist Dickkopf-1 (Dkk-1; 50, 100, or 200 ng/hemisphere). Twenty-four hours later, mice receiving vehicle remembered the familiar object explored during training. However, mice receiving Dkk-1 exhibited no memory for the training object, indicating that object recognition memory consolidation is dependent on canonical Wnt signaling. To determine how Dkk-1 affects canonical Wnt signaling, mice were infused with vehicle or 50 ng/hemisphere Dkk-1 and protein levels of Wnt-related proteins (Dkk-1, GSK3β, β-catenin, TCF1, LEF1, Cyclin D1, c-myc, Wnt7a, Wnt1, and PSD95) were measured in the dorsal hippocampus 5 min or 4 h later. Dkk-1 produced a rapid increase in Dkk-1 protein levels and a decrease in phosphorylated GSK3β levels, followed by a decrease in β-catenin, TCF1, LEF1, Cyclin D1, c-myc, Wnt7a, and PSD95 protein levels 4 h later. These data suggest that alterations in Wnt/GSK3β/β-catenin signaling may underlie the memory impairments induced by Dkk-1. In a subsequent experiment, object training alone rapidly increased DH GSK3β phosphorylation and levels of β-catenin and Cyclin D1. These data suggest that canonical Wnt signaling is regulated by object learning and is necessary for hippocampal memory consolidation.

  3. Canonical Wnt Signaling Regulates Atrioventricular Junction Programming and Electrophysiological Properties

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    Gillers, Benjamin S; Chiplunkar, Aditi; Aly, Haytham; Valenta, Tomas; Basler, Konrad; Christoffels, Vincent M.; Efimov, Igor R; Boukens, Bastiaan J; Rentschler, Stacey

    2014-01-01

    Rationale Proper patterning of the atrioventricular canal (AVC) is essential for delay of electrical impulses between atria and ventricles, and defects in AVC maturation can result in congenital heart disease. Objective To determine the role of canonical Wnt signaling in the myocardium during AVC development. Methods and Results We utilized a novel allele of β-catenin that preserves β-catenin’s cell adhesive functions but disrupts canonical Wnt signaling, allowing us to probe the effects of Wnt loss of function independently. We show that loss of canonical Wnt signaling in the myocardium results in tricuspid atresia with hypoplastic right ventricle associated with loss of AVC myocardium. In contrast, ectopic activation of Wnt signaling was sufficient to induce formation of ectopic AV junction-like tissue as assessed by morphology, gene expression, and electrophysiologic criteria. Aberrant AVC development can lead to ventricular preexcitation, a characteristic feature of Wolff-Parkinson-White syndrome. We demonstrate that postnatal activation of Notch signaling downregulates canonical Wnt targets within the AV junction. Stabilization of β-catenin protein levels can rescue Notch-mediated ventricular preexcitation and dysregulated ion channel gene expression. Conclusions Our data demonstrate that myocardial canonical Wnt signaling is an important regulator of AVC maturation and electrical programming upstream of Tbx3. Our data further suggests that ventricular preexcitation may require both morphologic patterning defects, as well as myocardial lineage reprogramming, to allow robust conduction across accessory pathway tissue. PMID:25599332

  4. The role of the Wnt canonical signaling in neurodegenerative diseases.

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    Libro, Rosaliana; Bramanti, Placido; Mazzon, Emanuela

    2016-08-01

    The Wnt/β-catenin or Wnt canonical pathway controls multiple biological processes throughout development and adult life. Growing evidences have suggested that deregulation of the Wnt canonical pathway could be involved in the pathogenesis of neurodegenerative diseases. The Wnt canonical signaling is a pathway tightly regulated, which activation results in the inhibition of the Glycogen Synthase Kinase 3β (GSK-3β) function and in increased β-catenin activity, that migrates into the nucleus, activating the transcription of the Wnt target genes. Conversely, when the Wnt canonical pathway is turned off, increased levels of GSK-3β promote β-catenin degradation. Hence, GSK-3β could be considered as a key regulator of the Wnt canonical pathway. Of note, GSK-3β has also been involved in the modulation of inflammation and apoptosis, determining the delicate balance between immune tolerance/inflammation and neuronal survival/neurodegeneration. In this review, we have summarized the current acknowledgements about the role of the Wnt canonical pathway in the pathogenesis of some neurodegenerative diseases including Alzheimer's disease, cerebral ischemia, Parkinson's disease, Huntington's disease, multiple sclerosis and amyotrophic lateral sclerosis, with particular regard to the main in vitro and in vivo studies in this field, by reviewing 85 research articles about.

  5. Agonistic and antagonistic roles for TNIK and MINK in non-canonical and canonical Wnt signalling.

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    Alexander Mikryukov

    Full Text Available Wnt signalling is a key regulatory factor in animal development and homeostasis and plays an important role in the establishment and progression of cancer. Wnt signals are predominantly transduced via the Frizzled family of serpentine receptors to two distinct pathways, the canonical ß-catenin pathway and a non-canonical pathway controlling planar cell polarity and convergent extension. Interference between these pathways is an important determinant of cellular and phenotypic responses, but is poorly understood. Here we show that TNIK (Traf2 and Nck-interacting kinase and MINK (Misshapen/NIKs-related kinase MAP4K signalling kinases are integral components of both canonical and non-canonical pathways in Xenopus. xTNIK and xMINK interact and are proteolytically cleaved in vivo to generate Kinase domain fragments that are active in signal transduction, and Citron-NIK-Homology (CNH Domain fragments that are suppressive. The catalytic activity of the Kinase domain fragments of both xTNIK and xMINK mediate non-canonical signalling. However, while the Kinase domain fragments of xTNIK also mediate canonical signalling, the analogous fragments derived from xMINK strongly antagonize this signalling. Our data suggest that the proteolytic cleavage of xTNIK and xMINK determines their respective activities and is an important factor in controlling the balance between canonical and non-canonical Wnt signalling in vivo.

  6. Controlled levels of canonical Wnt signaling are required for neural crest migration.

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    Maj, Ewa; Künneke, Lutz; Loresch, Elisabeth; Grund, Anita; Melchert, Juliane; Pieler, Tomas; Aspelmeier, Timo; Borchers, Annette

    2016-09-01

    Canonical Wnt signaling plays a dominant role in the development of the neural crest (NC), a highly migratory cell population that generates a vast array of cell types. Canonical Wnt signaling is required for NC induction as well as differentiation, however its role in NC migration remains largely unknown. Analyzing nuclear localization of β-catenin as readout for canonical Wnt activity, we detect nuclear β-catenin in premigratory but not migratory Xenopus NC cells suggesting that canonical Wnt activity has to decrease to basal levels to enable NC migration. To define a possible function of canonical Wnt signaling in Xenopus NC migration, canonical Wnt signaling was modulated at different time points after NC induction. This was accomplished using either chemical modulators affecting β-catenin stability or inducible glucocorticoid fusion constructs of Lef/Tcf transcription factors. In vivo analysis of NC migration by whole mount in situ hybridization demonstrates that ectopic activation of canonical Wnt signaling inhibits cranial NC migration. Further, NC transplantation experiments confirm that this effect is tissue-autonomous. In addition, live-cell imaging in combination with biophysical data analysis of explanted NC cells confirms the in vivo findings and demonstrates that modulation of canonical Wnt signaling affects the ability of NC cells to perform single cell migration. Thus, our data support the hypothesis that canonical Wnt signaling needs to be tightly controlled to enable migration of NC cells.

  7. Canonical Wnt signaling protects hippocampal neurons from Aβ oligomers: role of non-canonical Wnt-5a/Ca2+ in mitochondrial dynamics

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    Silva-Alvarez, Carmen; Arrázola, Macarena S.; Godoy, Juan A.; Ordenes, Daniela; Inestrosa, Nibaldo C.

    2013-01-01

    Alzheimer's disease (AD) is the most common type of age-related dementia. The disease is characterized by a progressive loss of cognitive abilities, severe neurodegeneration, synaptic loss and mitochondrial dysfunction. The Wnt signaling pathway participates in the development of the central nervous system and growing evidence indicates that Wnts also regulate the function of the adult nervous system. We report here, that indirect activation of canonical Wnt/β-catenin signaling using Bromoindirubin-30-Oxime (6-BIO), an inhibitor of glycogen synthase kinase-3β, protects hippocampal neurons from amyloid-β (Aβ) oligomers with the concomitant blockade of neuronal apoptosis. More importantly, activation with Wnt-5a, a non-canonical Wnt ligand, results in the modulation of mitochondrial dynamics, preventing the changes induced by Aβ oligomers (Aβo) in mitochondrial fission-fusion dynamics and modulates Bcl-2 increases induced by oligomers. The canonical Wnt-3a ligand neither the secreted Frizzled-Related Protein (sFRP), a Wnt scavenger, did not prevent these effects. In contrast, some of the Aβ oligomer effects were blocked by Ryanodine. We conclude that canonical Wnt/β-catenin signaling controls neuronal survival, and that non-canonical Wnt/Ca2+signaling modulates mitochondrial dysfunction. Since mitochondrial dysfunction is present in neurodegenerative diseases, the therapeutic possibilities of the activation of Wnt signaling are evident. PMID:23805073

  8. Primary cilia are not required for normal canonical Wnt signaling in the mouse embryo.

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    Polloneal Jymmiel R Ocbina

    Full Text Available Sonic hedgehog (Shh signaling in the mouse requires the microtubule-based organelle, the primary cilium. The primary cilium is assembled and maintained through the process of intraflagellar transport (IFT and the response to Shh is blocked in mouse mutants that lack proteins required for IFT. Although the phenotypes of mouse IFT mutants do not overlap with phenotypes of known Wnt pathway mutants, recent studies report data suggesting that the primary cilium modulates responses to Wnt signals.We therefore carried out a systematic analysis of canonical Wnt signaling in mutant embryos and cells that lack primary cilia because of loss of the anterograde IFT kinesin-II motor (Kif3a or IFT complex B proteins (Ift172 or Ift88. We also analyzed mutant embryos with abnormal primary cilia due to defects in retrograde IFT (Dync2h1. The mouse IFT mutants express the canonical Wnt target Axin2 and activate a transgenic canonical Wnt reporter, BAT-gal, in the normal spatial pattern and to the same quantitative level as wild type littermates. Similarly, mouse embryonic fibroblasts (MEFs derived from IFT mutants respond normally to added Wnt3a. The switch from canonical to non-canonical Wnt also appears normal in IFT mutant MEFs, as both wild-type and mutant cells do not activate the canonical Wnt reporter in the presence of both Wnt3a and Wnt5a.We conclude that loss of primary cilia or defects in retrograde IFT do not affect the response of the midgestation embryo or embryo-derived fibroblasts to Wnt ligands.

  9. Canonical Wnt Signaling as a Specific Marker of Normal and Tumorigenic Mammary Stem Cells

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    2013-02-01

    mammary epithelium impacts glandular development . We found ductal abnormali ties; however, the phenotype was not as severe as expected. Approximately...In previous reports we have clearly showed that cells w ith activated canonical Wnt signaling are present within the mammary epithelium starting at...Wnt1 transgenic cells. We generated a mouse line in which ~-catenin is conditionally deleted in the mammary epithelium of MMTV-Wnt1 transgenic

  10. Canonical Wnt signalling regulates epithelial patterning by modulating levels of laminins in zebrafish appendages.

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    Nagendran, Monica; Arora, Prateek; Gori, Payal; Mulay, Aditya; Ray, Shinjini; Jacob, Tressa; Sonawane, Mahendra

    2015-01-15

    The patterning and morphogenesis of body appendages - such as limbs and fins - is orchestrated by the activities of several developmental pathways. Wnt signalling is essential for the induction of limbs. However, it is unclear whether a canonical Wnt signalling gradient exists and regulates the patterning of epithelium in vertebrate appendages. Using an evolutionarily old appendage - the median fin in zebrafish - as a model, we show that the fin epithelium exhibits graded changes in cellular morphology along the proximo-distal axis. This epithelial pattern is strictly correlated with the gradient of canonical Wnt signalling activity. By combining genetic analyses with cellular imaging, we show that canonical Wnt signalling regulates epithelial cell morphology by modulating the levels of laminins, which are extracellular matrix components. We have unravelled a hitherto unknown mechanism involved in epithelial patterning, which is also conserved in the pectoral fins - evolutionarily recent appendages that are homologous to tetrapod limbs.

  11. Intra-epithelial requirement of canonical Wnt signaling for tooth morphogenesis.

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    Zhu, XiaoJing; Zhao, Pan; Liu, YuDong; Zhang, XiaoYun; Fu, Jiang; Ivy Yu, H-M; Qiu, Mengsheng; Chen, YiPing; Hsu, Wei; Zhang, Zunyi

    2013-04-26

    Multiple Wnt ligands are expressed in the developing tooth and play important and redundant functions during odontogenesis. However, the source of Wnt ligands and their targeting cells and action mechanism in tooth organogenesis remain largely elusive. Here we show that epithelial inactivation of Gpr177, the mouse Wntless (Wls) whose product regulates Wnt sorting and secretion, leads to arrest of tooth development at the early cap stage and abrogates tooth-forming capability of the dental epithelium. Gpr177 in the epithelium is necessary for the activation of canonical Wnt signaling in the dental epithelium and formation of a functional enamel knot. Epithelial deletion of Gpr177 results in defective gene expression and cellular behavior in the dental epithelium but does not alter odontogenic program in the mesenchyme. Furthermore, deletion of Axin2, a negative intracellular regulator of canonical Wnt signaling, rescues the tooth defects in mice carrying Gpr177 mutation in the dental epithelium. Together with the fact that active Wnt canonical signaling is present predominantly in the dental epithelium during tooth development, our results demonstrate that Gpr177-mediated Wnt ligands in the dental epithelium act primarily in an intra-epithelial context to regulate enamel knot formation and subsequent tooth development.

  12. Expression of canonical WNT/β-CATENIN signaling components in the developing human lung

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    Zhang Mingfeng

    2012-07-01

    Full Text Available Abstract Background The WNT/β-CATENIN signaling cascade is crucial for the patterning of the early lung morphogenesis in mice, but its role in the developing human lung remains to be determined. In this study, expression patterns of canonical WNT/β-CATENIN signaling components, including WNT ligands (WNT2, WNT7B, receptors ( FZD4, FZD7, LRP5, LRP6, transducers ( DVL2, DVL3, GSK-3β, β-CATENIN, APC, AXIN2, transcription factors ( TCF4, LEF1 and antagonists ( SOSTDC1 were examined in human embryonic lung at 7, 12, 17 and 21 weeks of gestation (W by real-time qRT-PCR and in situ hybridization. Results qRT-PCR analysis showed that some of these components were gradually upregulated, while some were significantly downregulated from the 7 W to the 12 W. However, most components reached a high level at 17 W, with a subsequent decrease at 21 W. In situ hybridization showed that the canonical WNT ligands and receptors were predominantly located in the peripheral epithelium, whereas the canonical WNT signal transducers and transcription factors were not only detected in the respiratory epithelium, but some were also scattered at low levels in the surrounding mesenchyme in the developing human lung. Furthermore, Western blot, qRT-PCR and histological analysis demonstrated that the β-CATENIN-dependent WNT signaling in embryonic human lung was activated in vitro by CHIR 99021 stimulation. Conclusions This study of the expression patterns and in vitro activity of the canonical WNT/β-CATENIN pathways suggests that these components play an essential role in regulation of human lung development.

  13. The ankyrin repeat protein Diversin recruits Casein kinase Iepsilon to the beta-catenin degradation complex and acts in both canonical Wnt and Wnt/JNK signaling.

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    Schwarz-Romond, T.; Asbrand, C.; Bakkers, J.; Kuhl, M.; Schaeffer, H.J.; Huelsken, J.; Behrens, J.; Hammerschmidt, M.; Birchmeier, W.

    2002-01-01

    Wnt signals control decisive steps in development and can induce the formation of tumors. Canonical Wnt signals control the formation of the embryonic axis, and are mediated by stabilization and interaction of beta-catenin with Lef/Tcf transcription factors. An alternative branch of the Wnt pathway

  14. BMP signaling negatively regulates bone mass through sclerostin by inhibiting the canonical Wnt pathway.

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    Kamiya, Nobuhiro; Ye, Ling; Kobayashi, Tatsuya; Mochida, Yoshiyuki; Yamauchi, Mitsuo; Kronenberg, Henry M; Feng, Jian Q; Mishina, Yuji

    2008-11-01

    Bone morphogenetic proteins (BMPs) are known to induce ectopic bone. However, it is largely unknown how BMP signaling in osteoblasts directly regulates endogenous bone. This study investigated the mechanism by which BMP signaling through the type IA receptor (BMPR1A) regulates endogenous bone mass using an inducible Cre-loxP system. When BMPR1A in osteoblasts was conditionally disrupted during embryonic bone development, bone mass surprisingly was increased with upregulation of canonical Wnt signaling. Although levels of bone formation markers were modestly reduced, levels of resorption markers representing osteoclastogenesis were severely reduced, resulting in a net increase in bone mass. The reduction of osteoclastogenesis was primarily caused by Bmpr1a-deficiency in osteoblasts, at least through the RANKL-OPG pathway. Sclerostin (Sost) expression was downregulated by about 90% and SOST protein was undetectable in osteoblasts and osteocytes, whereas the Wnt signaling was upregulated. Treatment of Bmpr1a-deficient calvariae with sclerostin repressed the Wnt signaling and restored normal bone morphology. By gain of Smad-dependent BMPR1A signaling in mice, Sost expression was upregulated and osteoclastogenesis was increased. Finally, the Bmpr1a-deficient bone phenotype was rescued by enhancing BMPR1A signaling, with restoration of osteoclastogenesis. These findings demonstrate that BMPR1A signaling in osteoblasts restrain endogenous bone mass directly by upregulating osteoclastogenesis through the RANKL-OPG pathway, or indirectly by downregulating canonical Wnt signaling through sclerostin, a Wnt inhibitor and a bone mass mediator.

  15. Novel synthetic antagonists of canonical Wnt signaling inhibit colorectal cancer cell growth.

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    Waaler, Jo; Machon, Ondrej; von Kries, Jens Peter; Wilson, Steven Ray; Lundenes, Elsa; Wedlich, Doris; Gradl, Dietmar; Paulsen, Jan Erik; Machonova, Olga; Dembinski, Jennifer L; Dinh, Huyen; Krauss, Stefan

    2011-01-01

    Canonical Wnt signaling is deregulated in several types of human cancer where it plays a central role in tumor cell growth and progression. Here we report the identification of 2 new small molecules that specifically inhibit canonical Wnt pathway at the level of the destruction complex. Specificity was verified in various cellular reporter systems, a Xenopus double-axis formation assay and a gene expression profile analysis. In human colorectal cancer (CRC) cells, the new compounds JW67 and JW74 rapidly reduced active β-catenin with a subsequent downregulation of Wnt target genes, including AXIN2, SP5, and NKD1. Notably, AXIN2 protein levels were strongly increased after compound exposure. Long-term treatment with JW74 inhibited the growth of tumor cells in both a mouse xenograft model of CRC and in Apc(Min) mice (multiple intestinal neoplasia, Min). Our findings rationalize further preclinical and clinical evaluation of these new compounds as novel modalities for cancer treatment.

  16. Canonical Wnt signaling promotes early hematopoietic progenitor formation and erythroid specification during embryonic stem cell differentiation.

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    Anuradha Tarafdar

    Full Text Available The generation of hematopoietic stem cells (HSCs during development is a complex process linked to morphogenic signals. Understanding this process is important for regenerative medicine applications that require in vitro production of HSC. In this study we investigated the effects of canonical Wnt/β-catenin signaling during early embryonic differentiation and hematopoietic specification using an embryonic stem cell system. Our data clearly demonstrates that following early differentiation induction, canonical Wnt signaling induces a strong mesodermal program whilst maintaining a degree of stemness potential. This involved a complex interplay between β-catenin/TCF/LEF/Brachyury/Nanog. β-catenin mediated up-regulation of TCF/LEF resulted in enhanced brachyury levels, which in-turn lead to Nanog up-regulation. During differentiation, active canonical Wnt signaling also up-regulated key transcription factors and cell specific markers essential for hematopoietic specification, in particular genes involved in establishing primitive erythropoiesis. This led to a significant increase in primitive erythroid colony formation. β-catenin signaling also augmented early hematopoietic and multipotent progenitor (MPP formation. Following culture in a MPP specific cytokine cocktail, activation of β-catenin suppressed differentiation of the early hematopoietic progenitor population, with cells displaying a higher replating capacity and a propensity to form megakaryocytic erythroid progenitors. This bias towards erythroid lineage commitment was also observed when hematopoietic progenitors were directed to undergo myeloid colony formation. Overall this study underscores the importance of canonical Wnt/β-catenin signaling in mesodermal specification, primitive erythropoiesis and early hematopietic progenitor formation during hematopoietic induction.

  17. Canonical Wnt signaling promotes early hematopoietic progenitor formation and erythroid specification during embryonic stem cell differentiation.

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    Tarafdar, Anuradha; Dobbin, Edwina; Corrigan, Pamela; Freeburn, Robin; Wheadon, Helen

    2013-01-01

    The generation of hematopoietic stem cells (HSCs) during development is a complex process linked to morphogenic signals. Understanding this process is important for regenerative medicine applications that require in vitro production of HSC. In this study we investigated the effects of canonical Wnt/β-catenin signaling during early embryonic differentiation and hematopoietic specification using an embryonic stem cell system. Our data clearly demonstrates that following early differentiation induction, canonical Wnt signaling induces a strong mesodermal program whilst maintaining a degree of stemness potential. This involved a complex interplay between β-catenin/TCF/LEF/Brachyury/Nanog. β-catenin mediated up-regulation of TCF/LEF resulted in enhanced brachyury levels, which in-turn lead to Nanog up-regulation. During differentiation, active canonical Wnt signaling also up-regulated key transcription factors and cell specific markers essential for hematopoietic specification, in particular genes involved in establishing primitive erythropoiesis. This led to a significant increase in primitive erythroid colony formation. β-catenin signaling also augmented early hematopoietic and multipotent progenitor (MPP) formation. Following culture in a MPP specific cytokine cocktail, activation of β-catenin suppressed differentiation of the early hematopoietic progenitor population, with cells displaying a higher replating capacity and a propensity to form megakaryocytic erythroid progenitors. This bias towards erythroid lineage commitment was also observed when hematopoietic progenitors were directed to undergo myeloid colony formation. Overall this study underscores the importance of canonical Wnt/β-catenin signaling in mesodermal specification, primitive erythropoiesis and early hematopietic progenitor formation during hematopoietic induction.

  18. ARF6-Regulated Endocytosis of Growth Factor Receptors Links Cadherin-Based Adhesion to Canonical Wnt Signaling in Epithelia

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    Pellon-Cardenas, Oscar; Clancy, James; Uwimpuhwe, Henriette; D'Souza-Schorey, Crislyn

    2013-01-01

    Wnt signaling has an essential role in embryonic development as well as stem/progenitor cell renewal, and its aberrant activation is implicated in many diseases, including several cancers. β-Catenin is a critical component of Wnt-mediated transcriptional activation. Here we show that ARF6 activation during canonical Wnt signaling promotes the intracellular accumulation of β-catenin via a mechanism that involves the endocytosis of growth factor receptors and robust activation of extracellular ...

  19. Cranial nerve development requires co-ordinated Shh and canonical Wnt signaling.

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    Kurosaka, Hiroshi; Trainor, Paul A; Leroux-Berger, Margot; Iulianella, Angelo

    2015-01-01

    Cranial nerves govern sensory and motor information exchange between the brain and tissues of the head and neck. The cranial nerves are derived from two specialized populations of cells, cranial neural crest cells and ectodermal placode cells. Defects in either cell type can result in cranial nerve developmental defects. Although several signaling pathways are known to regulate cranial nerve formation our understanding of how intercellular signaling between neural crest cells and placode cells is coordinated during cranial ganglia morphogenesis is poorly understood. Sonic Hedgehog (Shh) signaling is one key pathway that regulates multiple aspects of craniofacial development, but whether it co-ordinates cranial neural crest cell and placodal cell interactions during cranial ganglia formation remains unclear. In this study we examined a new Patched1 (Ptch1) loss-of-function mouse mutant and characterized the role of Ptch1 in regulating Shh signaling during cranial ganglia development. Ptch1(Wig/ Wig) mutants exhibit elevated Shh signaling in concert with disorganization of the trigeminal and facial nerves. Importantly, we discovered that enhanced Shh signaling suppressed canonical Wnt signaling in the cranial nerve region. This critically affected the survival and migration of cranial neural crest cells and the development of placodal cells as well as the integration between neural crest and placodes. Collectively, our findings highlight a novel and critical role for Shh signaling in cranial nerve development via the cross regulation of canonical Wnt signaling.

  20. Specification of osteoblast cell fate by canonical Wnt signaling requires Bmp2.

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    Salazar, Valerie S; Ohte, Satoshi; Capelo, Luciane P; Gamer, Laura; Rosen, Vicki

    2016-12-01

    Enhanced BMP or canonical Wnt (cWnt) signaling are therapeutic strategies employed to enhance bone formation and fracture repair, but the mechanisms each pathway utilizes to specify cell fate of bone-forming osteoblasts remain poorly understood. Among all BMPs expressed in bone, we find that singular deficiency of Bmp2 blocks the ability of cWnt signaling to specify osteoblasts from limb bud or bone marrow progenitors. When exposed to cWnts, Bmp2-deficient cells fail to progress through the Runx2/Osx1 checkpoint and thus do not upregulate multiple genes controlling mineral metabolism in osteoblasts. Cells lacking Bmp2 after induction of Osx1 differentiate normally in response to cWnts, suggesting that pre-Osx1(+) osteoprogenitors are an essential source and a target of BMP2. Our analysis furthermore reveals Grainyhead-like 3 (Grhl3) as a transcription factor in the osteoblast gene regulatory network induced during bone development and bone repair, which acts upstream of Osx1 in a BMP2-dependent manner. The Runx2/Osx1 transition therefore receives crucial regulatory inputs from BMP2 that are not compensated for by cWnt signaling, and this is mediated at least in part by induction and activation of Grhl3.

  1. The ankyrin repeat protein Diversin recruits Casein kinase Iepsilon to the beta-catenin degradation complex and acts in both canonical Wnt and Wnt/JNK signaling.

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    Schwarz-Romond, Thomas; Asbrand, Christian; Bakkers, Jeroen; Kühl, Michael; Schaeffer, Hans-Joerg; Huelsken, Jörg; Behrens, Jürgen; Hammerschmidt, Matthias; Birchmeier, Walter

    2002-08-15

    Wnt signals control decisive steps in development and can induce the formation of tumors. Canonical Wnt signals control the formation of the embryonic axis, and are mediated by stabilization and interaction of beta-catenin with Lef/Tcf transcription factors. An alternative branch of the Wnt pathway uses JNK to establish planar cell polarity in Drosophila and gastrulation movements in vertebrates. We describe here the vertebrate protein Diversin that interacts with two components of the canonical Wnt pathway, Casein kinase Iepsilon (CKIepsilon) and Axin/Conductin. Diversin recruits CKIepsilon to the beta-catenin degradation complex that consists of Axin/Conductin and GSK3beta and allows efficient phosphorylation of beta-catenin, thereby inhibiting beta-catenin/Tcf signals. Morpholino-based gene ablation in zebrafish shows that Diversin is crucial for axis formation, which depends on beta-catenin signaling. Diversin is also involved in JNK activation and gastrulation movements in zebrafish. Diversin is distantly related to Diego of Drosophila, which functions only in the pathway that controls planar cell polarity. Our data show that Diversin is an essential component of the Wnt-signaling pathway and acts as a molecular switch, which suppresses Wnt signals mediated by the canonical beta-catenin pathway and stimulates signaling via JNK.

  2. KCTD1 suppresses canonical Wnt signaling pathway by enhancing β-catenin degradation.

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    Xinxin Li

    Full Text Available The canonical Wnt signaling pathway controls normal embryonic development, cellular proliferation and growth, and its aberrant activity results in human carcinogenesis. The core component in regulation of this pathway is β-catenin, but molecular regulation mechanisms of β-catenin stability are not completely known. Here, our recent studies have shown that KCTD1 strongly inhibits TCF/LEF reporter activity. Moreover, KCTD1 interacted with β-catenin both in vivo by co-immunoprecipitation as well as in vitro through GST pull-down assays. We further mapped the interaction regions to the 1-9 armadillo repeats of β-catenin and the BTB domain of KCTD1, especially Position Ala-30 and His-33. Immunofluorescence analysis indicated that KCTD1 promotes the cytoplasmic accumulation of β-catenin. Furthermore, protein stability assays revealed that KCTD1 enhances the ubiquitination/degradation of β-catenin in a concentration-dependent manner in HeLa cells. And the degradation of β-catenin mediated by KCTD1 was alleviated by the proteasome inhibitor, MG132. In addition, KCTD1-mediated β-catenin degradation was dependent on casein kinase 1 (CK1- and glycogen synthase kinase-3β (GSK-3β-mediated phosphorylation and enhanced by the E3 ubiquitin ligase β-transducin repeat-containing protein (β-TrCP. Moreover, KCTD1 suppressed the expression of endogenous Wnt downstream genes and transcription factor AP-2α. Finally, we found that Wnt pathway member APC and tumor suppressor p53 influence KCTD1-mediated downregulation of β-catenin. These results suggest that KCTD1 functions as a novel inhibitor of Wnt signaling pathway.

  3. Canonical Wnt/β-catenin signalling is essential for optic cup formation.

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    Anna-Carin Hägglund

    Full Text Available A multitude of signalling pathways are involved in the process of forming an eye. Here we demonstrate that β-catenin is essential for eye development as inactivation of β-catenin prior to cellular specification in the optic vesicle caused anophthalmia in mice. By achieving this early and tissue-specific β-catenin inactivation we find that retinal pigment epithelium (RPE commitment was blocked and eye development was arrested prior to optic cup formation due to a loss of canonical Wnt signalling in the dorsal optic vesicle. Thus, these results show that Wnt/β-catenin signalling is required earlier and play a more central role in eye development than previous studies have indicated. In our genetic model system a few RPE cells could escape β-catenin inactivation leading to the formation of a small optic rudiment. The optic rudiment contained several neural retinal cell classes surrounded by an RPE. Unlike the RPE cells, the neural retinal cells could be β-catenin-negative revealing that differentiation of the neural retinal cell classes is β-catenin-independent. Moreover, although dorsoventral patterning is initiated in the mutant optic vesicle, the neural retinal cells in the optic rudiment displayed almost exclusively ventral identity. Thus, β-catenin is required for optic cup formation, commitment to RPE cells and maintenance of dorsal identity of the retina.

  4. Impact of laminitis on the canonical Wnt signaling pathway in basal epithelial cells of the equine digital laminae.

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    Le Wang

    Full Text Available The digital laminae is a two layer tissue that attaches the distal phalanx to the inner hoof wall, thus suspending the horse's axial skeleton in the hoof capsule. This tissue fails at the epidermal:dermal junction in laminitic horses, causing crippling disease. Basal epithelial cells line the laminar epidermal:dermal junction, undergo physiological change in laminitic horses, and lose versican gene expression. Versican gene expression is purportedly under control of the canonical Wnt signaling pathway and is a trigger for mesenchymal-to-epithelial transition; thus, its repression in laminar epithelial cells of laminitic horses may be associated with suppression of the canonical Wnt signaling pathway and loss of the epithelial cell phenotype. In support of the former contention, we show, using laminae from healthy horses and horses with carbohydrate overload-induced laminitis, quantitative real-time polymerase chain reaction, Western blotting after sodium dodecylsulfate polyacrylamide gel electrophoresis, and immunofluorescent tissue staining, that positive and negative regulatory components of the canonical Wnt signaling pathway are expressed in laminar basal epithelial cells of healthy horses. Furthermore, expression of positive regulators is suppressed and negative regulators elevated in laminae of laminitic compared to healthy horses. We also show that versican gene expression in the epithelial cells correlates positively with that of β-catenin and T-cell Factor 4, consistent with regulation by the canonical Wnt signaling pathway. In addition, gene and protein expression of β-catenin correlates positively with that of integrin β4 and both are strongly suppressed in laminar basal epithelial cells of laminitic horses, which remain E-cadherin(+/vimentin(-, excluding mesenchymal transition as contributing to loss of the adherens junction and hemidesmosome components. We propose that suppression of the canonical Wnt signaling pathway, and

  5. ARF6-regulated endocytosis of growth factor receptors links cadherin-based adhesion to canonical Wnt signaling in epithelia.

    Science.gov (United States)

    Pellon-Cardenas, Oscar; Clancy, James; Uwimpuhwe, Henriette; D'Souza-Schorey, Crislyn

    2013-08-01

    Wnt signaling has an essential role in embryonic development as well as stem/progenitor cell renewal, and its aberrant activation is implicated in many diseases, including several cancers. β-Catenin is a critical component of Wnt-mediated transcriptional activation. Here we show that ARF6 activation during canonical Wnt signaling promotes the intracellular accumulation of β-catenin via a mechanism that involves the endocytosis of growth factor receptors and robust activation of extracellular signal-regulated kinase (ERK). ERK promotes casein kinase 2-mediated phosphorylation of α-catenin, leading to destabilization of the adherens junctions and a subsequent increase in cytoplasmic pools of active β-catenin and E-cadherin. ERK also phosphorylates LRP6 to amplify the Wnt transduction pathway. The aforementioned Wnt-ERK signaling pathway initiates lumen filling of epithelial cysts by promoting cell proliferation in three-dimensional cell cultures. This study elucidates a mechanism responsible for the switch in β-catenin functions in cell adhesion at the adherens junctions and Wnt-induced nuclear signaling.

  6. Frat oncoproteins act at the crossroad of canonical and noncanonical Wnt-signaling pathways

    NARCIS (Netherlands)

    van Amerongen, R.; Nawijn, M. C.; Lambooij, J-P; Proost, N.; Jonkers, J.; Berns, A.

    2010-01-01

    Wnt-signal transduction is critical for development and tissue homeostasis in a wide range of animal species and is frequently deregulated in human cancers. Members of the Frat/GBP family of glycogen synthase kinase 3 beta (Gsk3b)binding oncoproteins are recognized as potent activators of the Wnt/be

  7. Resveratrol augments the canonical Wnt signaling pathway in promoting osteoblastic differentiation of multipotent mesenchymal cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Haibin; Shang, Linshan; Li, Xi; Zhang, Xiyu; Gao, Guimin; Guo, Chenhong; Chen, Bingxi; Liu, Qiji [Key Laboratory of Experimental Teratology, MOE, Institute of Molecular Medicine and Genetics, Shandong University, 44 Wen Hua Xi Lu, Jinan, Shandong 250012 (China); Gong, Yaoqin, E-mail: yxg8@sdu.edu.cn [Key Laboratory of Experimental Teratology, MOE, Institute of Molecular Medicine and Genetics, Shandong University, 44 Wen Hua Xi Lu, Jinan, Shandong 250012 (China); Shao, Changshun, E-mail: shao@biology.rutgers.edu [Key Laboratory of Experimental Teratology, MOE, Institute of Molecular Medicine and Genetics, Shandong University, 44 Wen Hua Xi Lu, Jinan, Shandong 250012 (China); Department of Genetics, Rutgers University, Piscataway, NJ 08854 (United States)

    2009-10-15

    Resveratrol has been shown to possess many health-benefiting effects, including the promotion of bone formation. In this report we investigated the mechanism by which resveratrol promotes osteoblastic differentiation from pluripotent mesenchymal cells. Since Wnt signaling is well documented to induce osteoblastogenesis and bone formation, we characterized the factors involved in Wnt signaling in response to resveratrol treatment. Resveratrol treatment of mesenchymal cells led to an increase in stabilization and nuclear accumulation of {beta}-catenin dose-dependently and time-dependently. As a consequence of the increased nuclear accumulation of {beta}-catenin, the ability to activate transcription of {beta}-catenin-TCF/LEF target genes that are required for osteoblastic differentiation was upregulated. However, resveratrol did not affect the initial step of the Wnt signaling pathway, as resveratrol was as effective in upregulating the activity of {beta}-catenin in cells in which Lrp5 was knocked down as in control cells. In addition, while conditioned medium enriched in Wnt signaling antagonist Dkk1 was able to inhibit Wnt3a-induced {beta}-catenin upregulation, this inhibitory effect can be abolished in resveratrol-treated cells. Furthermore, we showed that the level of glycogen synthase kinase 3{beta} (GSK-3{beta}), which phosphorylates and destabilizes {beta}-catenin, was reduced in response to resveratrol treatment. The phosphorylation of GSK-3{beta} requires extracellular signal-regulated kinase (ERK)1/2. Together, our data indicate that resveratrol promotes osteoblastogenesis and bone formation by augmenting Wnt signaling.

  8. Molecular Genetics of Intracranial Meningiomas with Emphasis on Canonical Wnt Signalling.

    Science.gov (United States)

    Pećina-Šlaus, Nives; Kafka, Anja; Lechpammer, Mirna

    2016-07-15

    Research over the last decade recognized the importance of novel molecular pathways in pathogenesis of intracranial meningiomas. In this review, we focus on human brain tumours meningiomas and the involvement of Wnt signalling pathway genes and proteins in this common brain tumour, describing their known functional effects. Meningiomas originate from the meningeal layers of the brain and the spinal cord. Most meningiomas have benign clinical behaviour and are classified as grade I by World Health Organization (WHO). However, up to 20% histologically classified as atypical (grade II) or anaplastic (grade III) are associated with higher recurrent rate and have overall less favourable clinical outcome. Recently, there is emerging evidence that multiple signalling pathways including Wnt pathway contribute to the formation and growth of meningiomas. In the review we present the synopsis on meningioma histopathology and genetics and discuss our research regarding Wnt in meningioma. Epithelial-to-mesenchymal transition, a process in which Wnt signalling plays an important role, is shortly discussed.

  9. The roles of canonical and non-canonical Wnt signaling in human de-differentiated articular chondrocytes

    NARCIS (Netherlands)

    Sassi, N.; Laadhar, L.; Allouche, M.; Zandieh-Doulabi, B.; Hamdoun, M.; Klein-Nulend, J.; Makni, S.; Sellami, S.

    2014-01-01

    Osteoarthritis is the most prevalent form of arthritis in the world and it is becoming a major public health problem. Osteoarthritic chondrocytes undergo morphological and biochemical changes that lead to de-differentiation. The involvement of signaling pathways, such as the Wnt pathway, during cart

  10. Porcupine homolog is required for canonical Wnt signaling and gastrulation in mouse embryos.

    Science.gov (United States)

    Biechele, Steffen; Cox, Brian J; Rossant, Janet

    2011-07-15

    Wnt signaling plays important roles in development and disease. The X-chromosomal Porcupine homolog gene (Porcn) encodes an evolutionary conserved member of the membrane bound O-acyl transferase (MBOAT) superfamily that has been shown to be required for the palmitoylation and secretion of Wnt3a, a mechanism that has been suggested to be conserved for all mammalian Wnt ligands. PORCN mutations in humans cause Focal Dermal Hypoplasia (FDH), a disorder causing developmental defects in heterozygous females and embryonic lethality in hemizygous males. In this study, Porcn mutant mouse embryonic stem (ES) cells were used to analyze the role of Porcn in mammalian embryonic development. In vitro, we show an exclusive requirement for Porcn in Wnt secreting cells and further, that any of the four Porcn isoforms is sufficient to allow for the secretion of functional Wnt3a. Embryos generated by aggregation of Porcn mutant ES cells with wildtype embryos fail to complete gastrulation in vivo, but remain in an epiblast-like state, similar to Wnt3 and Gpr177/Wls mutants. Consistent with this phenotype, in vitro differentiated mutant ES cells fail to generate endoderm and mesoderm derivatives. Taken together, these data confirm the importance of Porcn for Wnt secretion and gastrulation and suggest that disruption of early development underlies the male lethality of human PORCN mutants.

  11. Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Beildeck, Marcy E. [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States); Gelmann, Edward P. [Columbia University, Department of Medicine, New York, NY (United States); Byers, Stephen W., E-mail: byerss@georgetown.edu [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States)

    2010-07-01

    Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

  12. MMTV-Wnt1 and -DeltaN89beta-catenin induce canonical signaling in distinct progenitors and differentially activate Hedgehog signaling within mammary tumors.

    Directory of Open Access Journals (Sweden)

    Brigitte Teissedre

    Full Text Available Canonical Wnt/beta-catenin signaling regulates stem/progenitor cells and, when perturbed, induces many human cancers. A significant proportion of human breast cancer is associated with loss of secreted Wnt antagonists and mice expressing MMTV-Wnt1 and MMTV-DeltaN89beta-catenin develop mammary adenocarcinomas. Many studies have assumed these mouse models of breast cancer to be equivalent. Here we show that MMTV-Wnt1 and MMTV-DeltaN89beta-catenin transgenes induce tumors with different phenotypes. Using axin2/conductin reporter genes we show that MMTV-Wnt1 and MMTV-DeltaN89beta-catenin activate canonical Wnt signaling within distinct cell-types. DeltaN89beta-catenin activated signaling within a luminal subpopulation scattered along ducts that exhibited a K18(+ER(-PR(-CD24(highCD49f(low profile and progenitor properties. In contrast, MMTV-Wnt1 induced canonical signaling in K14(+ basal cells with CD24/CD49f profiles characteristic of two distinct stem/progenitor cell-types. MMTV-Wnt1 produced additional profound effects on multiple cell-types that correlated with focal activation of the Hedgehog pathway. We document that large melanocytic nevi are a hitherto unreported hallmark of early hyperplastic Wnt1 glands. These nevi formed along the primary mammary ducts and were associated with Hedgehog pathway activity within a subset of melanocytes and surrounding stroma. Hh pathway activity also occurred within tumor-associated stromal and K14(+/p63(+ subpopulations in a manner correlated with Wnt1 tumor onset. These data show MMTV-Wnt1 and MMTV-DeltaN89beta-catenin induce canonical signaling in distinct progenitors and that Hedgehog pathway activation is linked to melanocytic nevi and mammary tumor onset arising from excess Wnt1 ligand. They further suggest that Hedgehog pathway activation maybe a critical component and useful indicator of breast tumors arising from unopposed Wnt1 ligand.

  13. Fate Specification of Neural Plate Border by Canonical Wnt Signaling and Grhl3 is Crucial for Neural Tube Closure.

    Science.gov (United States)

    Kimura-Yoshida, Chiharu; Mochida, Kyoko; Ellwanger, Kristina; Niehrs, Christof; Matsuo, Isao

    2015-06-01

    During primary neurulation, the separation of a single-layered ectodermal sheet into the surface ectoderm (SE) and neural tube specifies SE and neural ectoderm (NE) cell fates. The mechanisms underlying fate specification in conjunction with neural tube closure are poorly understood. Here, by comparing expression profiles between SE and NE lineages, we observed that uncommitted progenitor cells, expressing stem cell markers, are present in the neural plate border/neural fold prior to neural tube closure. Our results also demonstrated that canonical Wnt and its antagonists, DKK1/KREMEN1, progressively specify these progenitors into SE or NE fates in accord with the progress of neural tube closure. Additionally, SE specification of the neural plate border via canonical Wnt signaling is directed by the grainyhead-like 3 (Grhl3) transcription factor. Thus, we propose that the fate specification of uncommitted progenitors in the neural plate border by canonical Wnt signaling and its downstream effector Grhl3 is crucial for neural tube closure. This study implicates that failure in critical genetic factors controlling fate specification of progenitor cells in the neural plate border/neural fold coordinated with neural tube closure may be potential causes of human neural tube defects.

  14. H-Prune through GSK-3β interaction sustains canonical WNT/β-catenin signaling enhancing cancer progression in NSCLC.

    Science.gov (United States)

    Carotenuto, Marianeve; De Antonellis, Pasqualino; Liguori, Lucia; Benvenuto, Giovanna; Magliulo, Daniela; Alonzi, Alessandro; Turino, Cecilia; Attanasio, Carmela; Damiani, Valentina; Bello, Anna Maria; Vitiello, Fabiana; Pasquinelli, Rosa; Terracciano, Luigi; Federico, Antonella; Fusco, Alfredo; Freeman, Jamie; Dale, Trevor C; Decraene, Charles; Chiappetta, Gennaro; Piantedosi, Francovito; Calabrese, Cecilia; Zollo, Massimo

    2014-07-30

    H-Prune hydrolyzes short-chain polyphosphates (PPase activity) together with an hitherto cAMP-phosphodiesterase (PDE), the latest influencing different human cancers by its overexpression. H-Prune promotes cell migration in cooperation with glycogen synthase kinase-3 (Gsk-3β). Gsk-3β is a negative regulator of canonical WNT/β-catenin signaling. Here, we investigate the role of Gsk-3β/h-Prune complex in the regulation of WNT/β-catenin signaling, demonstrating the h-Prune capability to activate WNT signaling also in a paracrine manner, through Wnt3a secretion. In vivo study demonstrates that h-Prune silencing inhibits lung metastasis formation, increasing mouse survival. We assessed h-Prune levels in peripheral blood of lung cancer patients using ELISA assay, showing that h-Prune is an early diagnostic marker for lung cancer. Our study dissects out the mechanism of action of h-Prune in tumorigenic cells and also sheds light on the identification of a new therapeutic target in non-small-cell lung cancer.

  15. Molecular Genetics of Intracranial Meningiomas with Emphasis on Canonical Wnt Signalling

    Directory of Open Access Journals (Sweden)

    Nives Pećina-Šlaus

    2016-07-01

    Full Text Available Research over the last decade recognized the importance of novel molecular pathways in pathogenesis of intracranial meningiomas. In this review, we focus on human brain tumours meningiomas and the involvement of Wnt signalling pathway genes and proteins in this common brain tumour, describing their known functional effects. Meningiomas originate from the meningeal layers of the brain and the spinal cord. Most meningiomas have benign clinical behaviour and are classified as grade I by World Health Organization (WHO. However, up to 20% histologically classified as atypical (grade II or anaplastic (grade III are associated with higher recurrent rate and have overall less favourable clinical outcome. Recently, there is emerging evidence that multiple signalling pathways including Wnt pathway contribute to the formation and growth of meningiomas. In the review we present the synopsis on meningioma histopathology and genetics and discuss our research regarding Wnt in meningioma. Epithelial-to-mesenchymal transition, a process in which Wnt signalling plays an important role, is shortly discussed.

  16. The fast track to canonical Wnt signaling in MC3T3-E1 cells protected by substance P against serum deprivation-induced apoptosis.

    Science.gov (United States)

    Yang, Jianguo; Nie, Jiping; Fu, Su; Liu, Song; Wu, Jianqun; Cui, Liang; Zhang, Yongtao; Yu, Bin

    2017-01-01

    The canonical Wnt pathway is vital to bone physiology by increasing bone mass through elevated osteoblast survival. Although investigated extensively in stem cells, its role in osteoblastic MC3T3-E1 cells has not been completely determined. To explore how this pathway is regulated by different conditions, we assessed the anti-apoptotic effects of substance P on the canonical Wnt pathway in MC3T3-E1 cells by treating cells with serum deprivation or serum starving with "substance P," a neuropeptide demonstrated to promote bone growth and stimulate Wnt signaling. The results showed that serum deprivation both induced apoptosis and activated Wnt signal transduction while substance P further stimulated the Wnt pathway via the NK-1 receptor but protected the cells from apoptotic death. Fast-tracking of Wnt signaling by substance P was also noted. These results indicate that nutritional deprivation and substance P synergistically activated the canonical Wnt pathway, a finding that helps to reveal the role of Wnt signaling in bone physiology affected by nutritional deprivation and neuropeptide substance P.

  17. Nuclear factor I-C reciprocally regulates adipocyte and osteoblast differentiation via control of canonical Wnt signaling.

    Science.gov (United States)

    Zhou, Jie; Wang, Shan; Qi, Qi; Yang, Xiaoyue; Zhu, Endong; Yuan, Hairui; Li, Xuemei; Liu, Ying; Li, Xiaoxia; Wang, Baoli

    2017-01-25

    Nuclear factor I-C (NFIC) has recently been identified as an important player in osteogenesis and bone homeostasis in vivo However, the molecular mechanisms involved have yet to be defined. In the current study, Nfic expression was altered in primary marrow stromal cells and established progenitor lines after adipogenic and osteogenic treatment. Overexpression of Nfic in stromal cells ST2, mesenchymal cells C3H10T1/2, and primary marrow stromal cells inhibited adipogenic differentiation, whereas it promoted osteogenic differentiation. Conversely, silencing of endogenous Nfic in the cell lines enhanced adipogenic differentiation, whereas it blocked osteogenic differentiation. Mechanism investigations revealed that Nfic overexpression promoted nuclear translocation of β-catenin and increased nuclear protein levels of β-catenin and transcription factor 7-like 2 (TCF7L2). Promoter studies and the chromatin immunoprecipitation (ChIP) assay revealed that NFIC directly binds to the promoter of low-density lipoprotein receptor-related protein 5 (Lrp5) and thereafter transactivates the promoter. Finally, inactivation of canonical Wnt signaling in ST2 attenuated the inhibition of adipogenic differentiation and stimulation of osteogenic differentiation by NFIC. Our study suggests that NFIC balances adipogenic and osteogenic differentiation from progenitor cells through controlling canonical Wnt signaling and highlights the potential of NFIC as a target for new therapies to control metabolic disorders like osteoporosis and obesity.-Zhou, J., Wang, S., Qi, Q., Yang, X., Zhu, E., Yuan, H., Li, X., Liu, Y., Li, X., Wang, B. Nuclear factor I-C reciprocally regulates adipocyte and osteoblast differentiation via control of canonical Wnt signaling.

  18. Zebrafish foxo3b negatively regulates canonical Wnt signaling to affect early embryogenesis.

    Directory of Open Access Journals (Sweden)

    Xun-wei Xie

    Full Text Available FOXO genes are involved in many aspects of development and vascular homeostasis by regulating cell apoptosis, proliferation, and the control of oxidative stress. In addition, FOXO genes have been showed to inhibit Wnt/β-catenin signaling by competing with T cell factor to bind to β-catenin. However, how important of this inhibition in vivo, particularly in embryogenesis is still unknown. To demonstrate the roles of FOXO genes in embryogenesis will help us to further understand their relevant physiological functions. Zebrafish foxo3b gene, an orthologue of mammalian FOXO3, was expressed maternally and distributed ubiquitously during early embryogenesis and later restricted to brain. After morpholino-mediated knockdown of foxo3b, the zebrafish embryos exhibited defects in axis and neuroectoderm formation, suggesting its critical role in early embryogenesis. The embryo-developmental marker gene staining at different stages, phenotype analysis and rescue assays revealed that foxo3b acted its role through negatively regulating both maternal and zygotic Wnt/β-catenin signaling. Moreover, we found that foxo3b could interact with zebrafish β-catenin1 and β-catenin2 to suppress their transactivation in vitro and in vivo, further confirming its role relevant to the inhibition of Wnt/β-catenin signaling. Taken together, we revealed that foxo3b played a very important role in embryogenesis and negatively regulated maternal and zygotic Wnt/β-catenin signaling by directly interacting with both β-catenin1 and β-catenin2. Our studies provide an in vivo model for illustrating function of FOXO transcription factors in embryogenesis.

  19. The low-density lipoprotein receptor-related protein 10 is a negative regulator of the canonical Wnt/{beta}-catenin signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Young-Hee; Sekiya, Manami; Hirata, Michiko; Ye, Mingjuan; Yamagishi, Azumi [Department of Molecular and Biochemical Nutrition, Graduate School of Human Life Science, Osaka City University, Osaka 558-8585 (Japan); Lee, Sang-Mi; Kang, Man-Jong [Department of Animal Science, College of Agriculture and Life Science, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Hosoda, Akemi; Fukumura, Tomoe; Kim, Dong-Ho [Department of Molecular and Biochemical Nutrition, Graduate School of Human Life Science, Osaka City University, Osaka 558-8585 (Japan); Saeki, Shigeru, E-mail: saeki@life.osaka-cu.ac.jp [Department of Molecular and Biochemical Nutrition, Graduate School of Human Life Science, Osaka City University, Osaka 558-8585 (Japan)

    2010-02-19

    Wnt signaling pathways play fundamental roles in the differentiation, proliferation and functions of many cells as well as developmental, growth, and homeostatic processes in animals. Low-density lipoprotein receptor (LDLR)-related protein (LRP) 5 and LRP6 serve as coreceptors of Wnt proteins together with Frizzled receptors, triggering activation of canonical Wnt/{beta}-catenin signaling. Here, we found that LRP10, a new member of the LDLR gene family, inhibits the canonical Wnt/{beta}-catenin signaling pathway. The {beta}-catenin/T cell factor (TCF) transcriptional activity in HEK293 cells was activated by transfection with Wnt3a or LRP6, which was then inhibited by co-transfection with LRP10. Deletion of the extracellular domain of LRP10 negated its inhibitory effect. The inhibitory effect of LRP10 was consistently conserved in HEK293 cells even when GSK3{beta} phosphorylation was inhibited by incubation with lithium chloride and co-transfection with constitutively active S33Y-mutated {beta}-catenin. Nuclear {beta}-catenin accumulation was unaffected by LRP10. The present studies suggest that LRP10 may interfere with the formation of the {beta}-catenin/TCF complex and/or its binding to target DNA in the nucleus, and that the extracellular domain of LRP10 is critical for inhibition of the canonical Wnt/{beta}-catenin signaling pathway.

  20. The Importance of the Canonical Wnt Signaling Pathway in the Porcine Endometrial Stromal Stem/Progenitor Cells: Implications for Regeneration

    Science.gov (United States)

    Bukowska, Joanna; Ziecik, Adam Janusz; Laguna, Joanna; Gawronska-Kozak, Barbara

    2015-01-01

    The regenerative ability of the endometrium is strongly associated with the presence of adult stem/progenitor cells. Purposes of the present study were (1) to establish the presence of stem/progenitor cells in porcine endometrial stroma using a clonogenic assay and (2) to investigate whether the canonical Wnt pathway affects the potential of stem/progenitor cells to undergo self-renewal or differentiation. The utility of endometrial stromal clones as a model for stem/progenitor studies was evaluated based on these cells' increased expression of mesenchymal stem cell (MSC) marker genes, including CD29, CD73, CD90, and CD105, compared with primary cultured cells. Small molecules were introduced to activate (BIO) or inhibit (XAV939) the canonical Wnt pathway during stromal clone formation. Cloning efficiency assays revealed that activation of the Wnt/β-catenin pathway promoted formation of more differentiated small clones. Moreover, activation of the Wnt/β-catenin pathway decreased, whereas inhibition of the pathway increased MSC marker expression. Additionally, we confirmed the importance of canonical Wnt pathway stimulation in endometrial stromal cells through observing the appropriate changes in β-catenin cellular localization. These data indicate that modulation of the canonical Wnt pathway effects the process of regeneration in the porcine endometrium during the course of the estrous cycle. PMID:26414529

  1. Downregulation of the Canonical WNT Signaling Pathway by TGFβ1 Inhibits Photoreceptor Differentiation of Adult Human Müller Glia with Stem Cell Characteristics

    Science.gov (United States)

    Angbohang, Angshumonik; Wu, Na; Charalambous, Thalis; Eastlake, Karen; Lei, Yuan; Kim, Yung Su; Sun, Xinghuai H.

    2016-01-01

    Müller glia are responsible for the retina regeneration observed in zebrafish. Although the human retina harbors Müller glia with stem cell characteristics, there is no evidence that they regenerate the retina after disease or injury. Transforming growth factor-β (TGFβ) and Wnt signaling regulate retinal neurogenesis and inflammation, but their roles in the neural differentiation of human Müller stem cells (hMSC) are not known. We examined hMSC lines in vitro for the expression of various Wnt signaling components and for their modulation by TGFβ1, as well as the effect of this cytokine on the photoreceptor differentiation of these cells. Culture of hMSC with a combination of factors that induce photoreceptor differentiation of hMSC (FGF2, taurine, retinoic acid, and insulin-like growth factor type1; FTRI), markedly upregulated the expression of components of the canonical Wnt signaling pathway, including WNT2B, DKK1, and active β-CATENIN. Although FTRI did not modify mRNA expression of WNT5B, a component of the noncanonical/planar cell polarity Wnt pathway, it upregulated its secretion. Furthermore, TGFβ1 not only decreased WNT2B expression, but also inhibited FTRI-induced photoreceptor differentiation of hMSC, as determined by expression of the photoreceptor markers NR2E3, RHODOPSIN, and RECOVERIN. Inhibition of TGFβ1 signaling by an ALK5 inhibitor prevented TGFβ1-induced changes in the expression of the two Wnt ligands examined. More importantly, inhibition of the canonical WNT signaling by XAV-939 prevented FTRI-induced photoreceptor differentiation. These observations suggest that TGFβ may play a key role in preventing neural differentiation of hMSC and may constitute a potential target for induction of endogenous regeneration of the human retina. PMID:26456050

  2. Identification of p62/SQSTM1 as a component of non-canonical Wnt VANGL2-JNK signalling in breast cancer.

    Science.gov (United States)

    Puvirajesinghe, Tania M; Bertucci, François; Jain, Ashish; Scerbo, Pierluigi; Belotti, Edwige; Audebert, Stéphane; Sebbagh, Michael; Lopez, Marc; Brech, Andreas; Finetti, Pascal; Charafe-Jauffret, Emmanuelle; Chaffanet, Max; Castellano, Rémy; Restouin, Audrey; Marchetto, Sylvie; Collette, Yves; Gonçalvès, Anthony; Macara, Ian; Birnbaum, Daniel; Kodjabachian, Laurent; Johansen, Terje; Borg, Jean-Paul

    2016-01-12

    The non-canonical Wnt/planar cell polarity (Wnt/PCP) pathway plays a crucial role in embryonic development. Recent work has linked defects of this pathway to breast cancer aggressiveness and proposed Wnt/PCP signalling as a therapeutic target. Here we show that the archetypal Wnt/PCP protein VANGL2 is overexpressed in basal breast cancers, associated with poor prognosis and implicated in tumour growth. We identify the scaffold p62/SQSTM1 protein as a novel VANGL2-binding partner and show its key role in an evolutionarily conserved VANGL2-p62/SQSTM1-JNK pathway. This proliferative signalling cascade is upregulated in breast cancer patients with shorter survival and can be inactivated in patient-derived xenograft cells by inhibition of the JNK pathway or by disruption of the VANGL2-p62/SQSTM1 interaction. VANGL2-JNK signalling is thus a potential target for breast cancer therapy.

  3. Mesodiencephalic dopaminergic neuronal differentiation does not involve GLI2A-mediated SHH-signaling and is under the direct influence of canonical WNT signaling.

    Science.gov (United States)

    Mesman, Simone; von Oerthel, Lars; Smidt, Marten P

    2014-01-01

    Sonic Hedgehog (SHH) and WNT proteins are key regulators in many developmental processes, like embryonic patterning and brain development. In the brain, SHH is expressed in a gradient starting in the floor plate (FP) progressing ventrally in the midbrain, where it is thought to be involved in the development and specification of mesodiencephalic dopaminergic (mdDA) neurons. GLI2A-mediated SHH-signaling induces the expression of Gli1, which is inhibited when cells start expressing SHH themselves. To determine whether mdDA neurons receive GLI2A-mediated SHH-signaling during differentiation, we used a BAC-transgenic mouse model expressing eGFP under the control of the Gli1 promoter. This mouse-model allowed for mapping of GLI2A-mediated SHH-signaling temporal and spatial in the mouse midbrain. Since mdDA neurons are born from E10.5, peaking at E11.0-E12.0, we examined Gli1-eGFP embryos at E11.5, E12.5, and E13.5, indicating whether Gli1 was induced before or during mdDA development and differentiation. Our data indicate that GLI2A-mediated SHH-signaling is not involved in mdDA neuronal differentiation. However, it appears to be involved in the differentiation of neurons which make up a subset of the red nucleus (RN). In order to detect whether mdDA neuronal differentiation may be under the control of canonical WNT-signaling, we used a transgenic mouse-line expressing LacZ under the influence of stable β-catenin. Here, we show that TH+ neurons of the midbrain receive canonical WNT-signaling during differentiation. Therefore, we suggest that early SHH-signaling is indirectly involved in mdDA development through early patterning of the midbrain area, whereas canonical WNT-signaling is directly involved in the differentiation of the mdDA neuronal population.

  4. 经典WNT信号通路与哺乳动物肺器官发育%Canonical WNT signaling pathway and mammalian lung development

    Institute of Scientific and Technical Information of China (English)

    施珏平; 滕鸿琦; 肖爱平; 李小兵; 张明凤

    2011-01-01

    Lung development is a consequence of interaction between epithelium and mesenchyme, which is regulated by several signaling pathways. It is well known that the canonical WNT signal pathway plays an important role in the regulation of cell proliferation, apoptosis and differentiation. Recent studies on model organisms, such as mouse and rat, verified that the canonical WNT signal pathway participated in the regulation of mammalian lung development. This review has summarized the main recent research findings on the role of canonical WNT signaling components in the regulation of mammalian lung development. The gene expression and function in all members of canonical WNT signaling pathway, and the possible lung diseases induced by abnormal expression of canonical WNT signaling components during the mammalian lung development were emphasized to state. This review will provide valuable information for further illustration of the molecular mechanisms of WNT signals in the regulation of human lung development, as well as will be in favor of finding the way to diagnose and cure human lung diseases.%肺器官发育是上皮和间充质相互作用的过程,由多条信号通路共同调控.已知经典WNT信号通路对细胞的增殖、凋亡和分化起着重要的调控作用,在小鼠等模式生物上研究发现,它也参与了哺乳动物肺器官发育的调控过程.综述近年来经典WNT信号通路成员在哺乳动物肺器官发育过程中的表达变化、作用功能及表达异常可能诱发的肺部疾病,以期为研究经典WNT信号通路调控人类肺器官发育的分子机制及相关肺部疾病的诊治奠定基础.

  5. Effect of activation of canonical Wnt signaling by the Wnt-3a protein on the susceptibility of PC12 cells to oxidative and apoptotic insults

    Energy Technology Data Exchange (ETDEWEB)

    Kawamoto, E.M. [Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil); Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD (United States); Gleichmann, M. [Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD (United States); Yshii, L.M.; Sá Lima, L. de [Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil); Mattson, M.P. [Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD (United States); Scavone, C. [Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil)

    2011-11-25

    Wnt proteins are involved in tissue development and their signaling pathways play an important role during embryogenesis. Wnt signaling can promote cell survival, which is beneficial for neurons, but could also lead to tumor development in different tissues. The present study investigated the effects of a Wnt protein on the susceptibility of a neural tumor cell line (PC12 cells) to the cytotoxic compounds ferrous sulfate (10 mM), staurosporine (100 and 500 nM), 3-nitropropionic acid (5 mM), and amyloid β-peptide (Aβ{sub 25-35}; 50 µM). Cells (1 × 10{sup 6} cells/mL) were treated with the Wnt-3a recombinant peptide (200 ng/mL) for 24 h before exposure to toxic insults. The Wnt-3a protein partially protected PC12 cells, with a 6-15% increase in cell viability in the presence of toxic agents, similar to the effect measured using the MTT and lactate dehydrogenase cell viability assays. The Wnt-3a protein increased protein expression of β-catenin by 52% compared to control. These findings suggest that Wnt signaling can protect neural cells against apoptosis induced by toxic agents, which are relevant to the pathogenesis of Alzheimer's and Huntington's diseases.

  6. Effect of activation of canonical Wnt signaling by the Wnt-3a protein on the susceptibility of PC12 cells to oxidative and apoptotic insults

    Directory of Open Access Journals (Sweden)

    E.M. Kawamoto

    2012-01-01

    Full Text Available Wnt proteins are involved in tissue development and their signaling pathways play an important role during embryogenesis. Wnt signaling can promote cell survival, which is beneficial for neurons, but could also lead to tumor development in different tissues. The present study investigated the effects of a Wnt protein on the susceptibility of a neural tumor cell line (PC12 cells to the cytotoxic compounds ferrous sulfate (10 mM, staurosporine (100 and 500 nM, 3-nitropropionic acid (5 mM, and amyloid β-peptide (Aβ25-35; 50 µM. Cells (1 x 10(6 cells/mL were treated with the Wnt-3a recombinant peptide (200 ng/mL for 24 h before exposure to toxic insults. The Wnt-3a protein partially protected PC12 cells, with a 6-15% increase in cell viability in the presence of toxic agents, similar to the effect measured using the MTT and lactate dehydrogenase cell viability assays. The Wnt-3a protein increased protein expression of β-catenin by 52% compared to control. These findings suggest that Wnt signaling can protect neural cells against apoptosis induced by toxic agents, which are relevant to the pathogenesis of Alzheimer’s and Huntington’s diseases.

  7. Inhibition of canonical WNT/β-catenin signaling is involved in leflunomide (LEF)-mediated cytotoxic effects on renal carcinoma cells.

    Science.gov (United States)

    Chen, Yicheng; Huang, Qiaoli; Zhou, Hua; Wang, Yueping; Hu, Xian; Li, Tao

    2016-08-02

    Leflunomide (LEF), an inhibitor of dihydroorotate dehydrogenase (DHODH) in pyrimidine biosynthetic pathway, is an immunomodulatory agent approved for the treatment of rheumatoid arthritis. In this study, we show that LEF significantly reduced cell proliferation of renal carcinoma cells in a concentration-dependent manner. LEF at 50 μM induced S-phase arrest and autophagy. Higher doses of LEF (>50 μM) effectively induced cell apoptosis. Modulating the concentration of LEF resulted in distinct effects on the expression of regulatory proteins associated with cell cycle, apoptosis, and autophagy. In particular, high concentrations of LEF inhibited canonical WNT signaling by promoting nucleo-cytoplasmic shuttling and proteasome-dependent degradation of β-catenin. Mechanistic studies showed that the repression of AKT activation partly accounted for LEF-mediated WNT inhibition. Gene expression microarray revealed that LEF treatment greatly inhibited the expression of FZD10 gene, a receptor mediating WNT/β-catenin activation. In vivo xenograft study in NOD/SCID mice further validated the inhibitory effects of LEF on tumor growth and Wnt/β-catenin signaling. However, LEF treatment also triggered cell autophagy and elevated the expression of WNT3a, which ameliorated its cytotoxic effects. The combination of LEF with a WNT inhibitor IWP-2 or autophagy inhibitor HCQ could yield an enhanced anti-tumor outcome. Taken together, these results identify the potential utility and pharmacological feature of LEF in the chemotherapy of renal cell carcinoma (RCC).

  8. Regulation of Monocarboxylic Acid Transporter 1 Trafficking by the Canonical Wnt/β-Catenin Pathway in Rat Brain Endothelial Cells Requires Cross-talk with Notch Signaling.

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    Liu, Zejian; Sneve, Mary; Haroldson, Thomas A; Smith, Jeffrey P; Drewes, Lester R

    2016-04-01

    The transport of monocarboxylate fuels such as lactate, pyruvate, and ketone bodies across brain endothelial cells is mediated by monocarboxylic acid transporter 1 (MCT1). Although the canonical Wnt/β-catenin pathway is required for rodent blood-brain barrier development and for the expression of associated nutrient transporters, the role of this pathway in the regulation of brain endothelial MCT1 is unknown. Here we report expression of nine members of the frizzled receptor family by the RBE4 rat brain endothelial cell line. Furthermore, activation of the canonical Wnt/β-catenin pathway in RBE4 cells via nuclear β-catenin signaling with LiCl does not alter brain endothelialMct1mRNA but increases the amount of MCT1 transporter protein. Plasma membrane biotinylation studies and confocal microscopic examination of mCherry-tagged MCT1 indicate that increased transporter results from reduced MCT1 trafficking from the plasma membrane via the endosomal/lysosomal pathway and is facilitated by decreased MCT1 ubiquitination following LiCl treatment. Inhibition of the Notch pathway by the γ-secretase inhibitorN-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycinet-butyl ester negated the up-regulation of MCT1 by LiCl, demonstrating a cross-talk between the canonical Wnt/β-catenin and Notch pathways. Our results are important because they show, for the first time, the regulation of MCT1 in cerebrovascular endothelial cells by the multifunctional canonical Wnt/β-catenin and Notch signaling pathways.

  9. Identification of p62/SQSTM1 as a component of non-canonical Wnt VANGL2–JNK signalling in breast cancer

    Science.gov (United States)

    Puvirajesinghe, Tania M.; Bertucci, François; Jain, Ashish; Scerbo, Pierluigi; Belotti, Edwige; Audebert, Stéphane; Sebbagh, Michael; Lopez, Marc; Brech, Andreas; Finetti, Pascal; Charafe-Jauffret, Emmanuelle; Chaffanet, Max; Castellano, Rémy; Restouin, Audrey; Marchetto, Sylvie; Collette, Yves; Gonçalvès, Anthony; Macara, Ian; Birnbaum, Daniel; Kodjabachian, Laurent; Johansen, Terje; Borg, Jean-Paul

    2016-01-01

    The non-canonical Wnt/planar cell polarity (Wnt/PCP) pathway plays a crucial role in embryonic development. Recent work has linked defects of this pathway to breast cancer aggressiveness and proposed Wnt/PCP signalling as a therapeutic target. Here we show that the archetypal Wnt/PCP protein VANGL2 is overexpressed in basal breast cancers, associated with poor prognosis and implicated in tumour growth. We identify the scaffold p62/SQSTM1 protein as a novel VANGL2-binding partner and show its key role in an evolutionarily conserved VANGL2–p62/SQSTM1–JNK pathway. This proliferative signalling cascade is upregulated in breast cancer patients with shorter survival and can be inactivated in patient-derived xenograft cells by inhibition of the JNK pathway or by disruption of the VANGL2–p62/SQSTM1 interaction. VANGL2–JNK signalling is thus a potential target for breast cancer therapy. PMID:26754771

  10. Activation of canonical WNT/β-catenin signaling enhances in vitro motility of glioblastoma cells by activation of ZEB1 and other activators of epithelial-to-mesenchymal transition.

    Science.gov (United States)

    Kahlert, Ulf D; Maciaczyk, Donata; Doostkam, Soroush; Orr, Brent A; Simons, Brian; Bogiel, Tomasz; Reithmeier, Thomas; Prinz, Marco; Schubert, Jörg; Niedermann, Gabriele; Brabletz, Thomas; Eberhart, Charles G; Nikkhah, Guido; Maciaczyk, Jaroslaw

    2012-12-01

    Here we show that activation of the canonical WNT/β-catenin pathway increases the expression of stem cell genes and promotes the migratory and invasive capacity of glioblastoma. Modulation of WNT signaling alters the expression of epithelial-to-mesenchymal transition activators, suggesting a role of this process in the regulation of glioma motility. Using immunohistochemistry in patient-derived glioblastoma samples we showed higher numbers of cells with intranuclear signal for β-catenin in the infiltrating edge of tumor compared to central tumor parenchyma. These findings suggest that canonical WNT/β-catenin pathway is a critical regulator of GBM invasion and may represent a potential therapeutic target.

  11. Effect of Pulsed Electromagnetic Field on Bone Formation and Lipid Metabolism of Glucocorticoid-Induced Osteoporosis Rats through Canonical Wnt Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Yuan Jiang

    2016-01-01

    Full Text Available Pulsed electromagnetic field (PEMF has been suggested as a promising method alternative to drug-based therapies for treating osteoporosis (OP, but the role of PEMF in GIOP animal models still remains unknown. This study was performed to investigate the effect of PEMF on bone formation and lipid metabolism and further explored the several important components and targets of canonical Wnt signaling pathway in GIOP rats. After 12 weeks of intervention, bone mineral density (BMD level of the whole body increased significantly, serum lipid levels decreased significantly, and trabeculae were thicker in GIOP rats of PEMF group. PEMF stimulation upregulated the mRNA and protein expression of Wnt10b, LRP5, β-catenin, OPG, and Runx2 and downregulated Axin2, PPAR-γ, C/EBPα, FABP4, and Dkk-1. The results of this study suggested that PEMF stimulation can prevent bone loss and improve lipid metabolism disorders in GIOP rats. Canonical Wnt signaling pathway plays an important role in bone formation and lipid metabolism during PEMF stimulation.

  12. Wnt signaling and colon carcinogenesis: Beyond APC

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    Rani Najdi

    2011-01-01

    Full Text Available Activation of the Wnt signaling pathway via mutation of the adenomatous polyposis coli gene (APC is a critical event in the development of colon cancer. For colon carcinogenesis, however, constitutive signaling through the canonical Wnt pathway is not a singular event. Here we review how canonical Wnt signaling is modulated by intracellular LEF/TCF composition and location, the action of different Wnt ligands, and the secretion of Wnt inhibitory molecules. We also review the contributions of non-canonical Wnt signaling and other distinct pathways in the tumor micro environment that cross-talk to the canonical Wnt pathway and thereby influence colon cancer progression. These ′non-APC′ aspects of Wnt signaling are considered in relation to the development of potential agents for the treatment of patients with colon cancer. Regulatory pathways that influence Wnt signaling highlight how it might be possible to design therapies that target a network of signals beyond that of APC and β-catenin.

  13. A phenotypic screen in zebrafish identifies a novel small-molecule inducer of ectopic tail formation suggestive of alterations in non-canonical Wnt/PCP signaling.

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    Evelien Gebruers

    Full Text Available Zebrafish have recently emerged as an attractive model for the in vivo bioassay-guided isolation and characterization of pharmacologically active small molecules of natural origin. We carried out a zebrafish-based phenotypic screen of over 3000 plant-derived secondary metabolite extracts with the goal of identifying novel small-molecule modulators of the BMP and Wnt signaling pathways. One of the bioactive plant extracts identified in this screen - Jasminum gilgianum, an Oleaceae species native to Papua New Guinea - induced ectopic tails during zebrafish embryonic development. As ectopic tail formation occurs when BMP or non-canonical Wnt signaling is inhibited during the tail protrusion process, we suspected a constituent of this extract to act as a modulator of these pathways. A bioassay-guided isolation was carried out on the basis of this zebrafish phenotype, identifying para-coumaric acid methyl ester (pCAME as the active compound. We then performed an in-depth phenotypic analysis of pCAME-treated zebrafish embryos, including a tissue-specific marker analysis of the secondary tails. We found pCAME to synergize with the BMP-inhibitors dorsomorphin and LDN-193189 in inducing ectopic tails, and causing convergence-extension defects in compound-treated embryos. These results indicate that pCAME may interfere with non-canonical Wnt signaling. Inhibition of Jnk, a downstream target of Wnt/PCP signaling (via morpholino antisense knockdown and pharmacological inhibition with the kinase inhibitor SP600125 phenocopied pCAME-treated embryos. However, immunoblotting experiments revealed pCAME to not directly inhibit Jnk-mediated phosphorylation of c-Jun, suggesting additional targets of SP600125, and/or other pathways, as possibly being involved in the ectopic tail formation activity of pCAME. Further investigation of pCAME's mechanism of action will help determine this compound's pharmacological utility.

  14. Three-dimensional culture of sebaceous gland cells revealing the role of prostaglandin E{sub 2}-induced activation of canonical Wnt signaling

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Go J., E-mail: medical21go@yahoo.co.jp; Saya, Hideyuki

    2013-09-06

    Highlights: •Three-dimensional culture generates “semi-vivo” sebaceous glands. •Xenograft model failed to mimic the biology of sebaceous glands in vivo. •Proinflammatory cytokine PGE{sub 2} enhances Wnt signal activity in the organoids. •PGE{sub 2} influences on the mitochondrial and lipid metabolism in the organoids. •Considering 3R agenda, “semi-vivo” sebaceous glands are useful for research. -- Abstract: Background: Prostaglandin E{sub 2} (PGE{sub 2}) is a proinflammatory mediator and activates the canonical Wnt–β-catenin signaling pathway in hematopoietic stem cells. The SZ95 cell line was established from human sebaceous gland cells and is studied as a model system for these cells. Given that 2D culture of SZ95 cells does not recapitulate the organization of sebaceous glands in situ, we developed a 3D culture system for these cells and examined the effects of PGE{sub 2} on cell morphology and function. Results: SZ95 cells maintained in 3D culture formed organoids that mimicked the organization of sebaceous glands in situ, including the establishment of a basement membrane. Organoids exposed to PGE{sub 2} were larger and adopted a more complex organization compared with control organoids. PGE{sub 2} activated the canonical Wnt signaling pathway as well as increased cell viability and proliferation, mitochondrial metabolism, and lipid synthesis in the organoids. Conclusions: Culture of SZ95 cells in 3D culture system recapitulates the structure and susceptibility to PGE{sub 2} of sebaceous glands in situ and should prove useful for studies of the response of these glands to inflammation and other environmental stressors. Our results also implicate PGE{sub 2}-induced activation of canonical Wnt signaling pathway in regulation of the morphology,proliferation, and function of “semi-vivo” sebaceous glands.

  15. Induction of CXC chemokines in human mesenchymal stemcells by stimulation with secreted frizzled-related proteinsthrough non-canonical Wnt signaling

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    AIM To investigate the effect of secreted frizzledrelatedproteins (sFRPs) on CXC chemokine expressionin human mesenchymal stem cells (hMSCs).METHODS: CXC chemokines such as CXCL5 andCXCL8 are induced in hMSCs during differentiation withosteogenic differentiation medium (OGM) and may beinvolved in angiogenic stimulation during bone repair.hMSCs were treated with conditioned medium (CM) fromL-cells expressing non-canonical Wnt5a protein, or withcontrol CM from wild type L-cells, or directly with sFRPsfor up to 10 d in culture. mRNA expression levels of bothCXCL5 and CXCL8 were quantitated by real-time reversetranscriptase-polymerase chain reaction and secretedprotein levels of these proteins determined by ELISA.Dose- (0-500 ng/mL) and time-response curves weregenerated for treatment with sFRP1. Signal transductionpathways were explored by western blot analysis withpan- or phosphorylation-specific antibodies, through useof specific pathway inhibitors, and through use of siRNAstargeting specific frizzled receptors (Fzd)-2 and 5 or the receptor tyrosine kinase-like orphan receptor-2 (RoR2)prior to treatment with sFRPs.RESULTS: CM from L-cells expressing Wnt5a, a noncanonicalWnt, stimulated an increase in CXCL5 mRNAexpression and protein secretion in comparison to controlL-cell CM. sFRP1, which should inhibit both canonicaland non-canonical Wnt signaling, surprisingly enhancedthe expression of CXCL5 at 7 and 10 d. Dickkopf1, aninhibitor of canonical Wnt signaling prevented the sFRPstimulatedinduction of CXCL5 and actually inhibitedbasal levels of CXCL5 expression at 7 but not at 10 d posttreatment. In addition, all four sFRPs isoforms inducedCXCL8 expression in a dose- and time-dependent mannerwith maximum expression at 7 d with treatment at 150ng/mL. The largest increases in CXCL5 expression wereseen from stimulation with sFRP1 or sFRP2. Analysis ofmitogen-activated protein kinase signaling pathwaysin the presence of OGM showed sFRP1

  16. A deep investigation into the adipogenesis mechanism: Profile of microRNAs regulating adipogenesis by modulating the canonical Wnt/β-catenin signaling pathway

    Directory of Open Access Journals (Sweden)

    Li Jing

    2010-05-01

    Full Text Available Abstract Background MicroRNAs (miRNAs are a large class of tiny non-coding RNAs (~22-24 nt that regulate diverse biological processes at the posttranscriptional level by controlling mRNA stability or translation. As a molecular switch, the canonical Wnt/β-catenin signaling pathway should be suppressed during the adipogenesis; However, activation of this pathway leads to the inhibition of lipid depots formation. The aim of our studies was to identify miRNAs that might be involved in adipogenesis by modulating WNT signaling pathway. Here we established two types of cell model, activation and repression of WNT signaling, and investigated the expression profile of microRNAs using microarray assay. Results The high throughput microarray data revealed 18 miRNAs that might promote adipogenesis by repressing WNT signaling: miR-210, miR-148a, miR-194, miR-322 etc. Meanwhile, we also identified 29 miRNAs that might have negative effect on adipogenesis by activating WNT signaling: miR-344, miR-27 and miR-181 etc. The targets of these miRNAs were also analysed by bioinformatics. To validate the predicted targets and the potential functions of these identified miRNAs, the mimics of miR-210 were transfected into 3T3-L1 cells and enlarged cells with distinct lipid droplets were observed; Meanwhile, transfection with the inhibitor of miR-210 could markedly decrease differentiation-specific factors at the transcription level, which suggested the specific role of miR-210 in promoting adipogenesis. Tcf7l2, the predicted target of miR-210, is a transcription factor triggering the downstream responsive genes of WNT signaling, was blocked at transcription level. Furthermore, the activity of luciferase reporter bearing Tcf7l2 mRNA 3' UTR was decreased after co-transfection with miR-210 in HEK-293FT cells. Last but not least, the protein expression level of β-catenin was increased in the lithium (LiCl treated 3T3-L1 cells after transfection with miR-210. These

  17. Comparative integromics on non-canonical WNT or planar cell polarity signaling molecules: transcriptional mechanism of PTK7 in colorectal cancer and that of SEMA6A in undifferentiated ES cells.

    Science.gov (United States)

    Katoh, Masuko; Katoh, Masaru

    2007-09-01

    Non-canonical WNT and planar cell polarity (PCP) are overlapping but distinct signaling pathways, which control convergent extension, neural tube closure, orientation of cilia and sensory hair cells, axon guidance, and cell motility. Non-canonical WNT signals, regulated by the interaction of WNT, WNT antagonist, Frizzled and ROR2, are transduced to JNK, ROCK, PKC, MAP3K7, and NFAT signaling cascades. PCP signals, regulated by the interaction of VANGL-PRICKLE complex, CELSR and Frizzled-DVL complex, are transduced to JNK, ROCK, and other uncharacterized signaling cascades. PTK7 signaling, regulated by SEMA6 and Plexin-A family members, affects PCP pathway through VANGL. Here, integrative genomic analyses on WNT5A, WNT5B, WNT11, FZD3, FZD6, ROR1, ROR2, RYK, CELSR1, CELSR2, CELSR3, VANGL1, VANGL2, PRICKLE1, PRICKLE2, PTK7, SEMA6A, SEMA6B, SEMA6C and SEMA6D were carried out. PTK7 and SEMA6A were expressed in undifferentiated embryonic stem (ES) cells, SEMA6A in endodermal progenitors, CELSR1, VANGL1 and PTK7 in gastrointestinal tumors. CELSR2, PRICKLE2 and SEMA6C were expressed in fetal brain, CELSR2, PRICKLE1 and SEMA6A in adult brain, WNT5A and CELSR3 in adult brain tumors. These facts indicate class switches of non-canonical WNT or PCP signaling molecules during embryogenesis and carcinogenesis. TCF/LEF-, SP1-, and 5 bHLH-binding sites within human PTK7 promoter were conserved in chimpanzee, rhesus monkey, mouse, and rat PTK7 orthologs, which explained the mechanism of PTK7 upregulation in colorectal cancer. NANOG-, SOX2-, and POU5F1 (OCT3/OCT4)-binding sites within intron 1 of the human SEMA6A gene were conserved in chimpanzee, rhesus monkey, mouse, and rat SEMA6A orthologs, which explained the mechanism of SEMA6A upregulation in undifferentiated ES cells. Most of non-canonical WNT or PCP signaling molecules, except PTK7 and SEMA6A, were not frequently expressed in undifferentiated human ES cells. Non-canonical WNT or PCP signaling pathway, activated to orchestrate

  18. FGF and canonical Wnt signaling cooperate to induce paraxial mesoderm from tailbud neuromesodermal progenitors through regulation of a two-step EMT.

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    Goto, Hana; Kimmey, Samuel C; Row, Richard H; Matus, David Q; Martin, Benjamin L

    2017-02-27

    Mesoderm induction begins during gastrulation. Recent evidence from several vertebrate species indicates mesoderm induction continues after gastrulation in neuromesodermal progenitor cells (NMPs) within the posterior-most embryonic structure called the tailbud. It is unclear to what extent the molecular mechanisms of mesoderm induction are conserved between gastrula and post-gastrula stages of development. Fibroblast growth factor (FGF) signaling is required for mesoderm induction during gastrulation through positive transcriptional regulation of the t-box transcription factor brachyury (ntla in zebrafish). We find that FGF is continuously required for paraxial mesoderm (PM) induction in post-gastrula NMPs, but has the opposite effect on brachyury expression. FGF signaling represses brachyury and the NMP marker sox2 through regulation of tbx16 and msgn1, thereby committing cells to a PM fate. FGF mediated PM induction in NMPs functions in tight coordination with canonical Wnt signaling during the epithelial to mesenchymal transition from NMP to mesodermal progenitor. Wnt signaling initiates the EMT, while FGF signaling terminates this event. Our results indicate that germ layer induction in the tailbud is not a simple continuation of gastrulation events.

  19. A novel role for MuSK and non-canonical Wnt signaling during segmental neural crest cell migration.

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    Banerjee, Santanu; Gordon, Laura; Donn, Thomas M; Berti, Caterina; Moens, Cecilia B; Burden, Steven J; Granato, Michael

    2011-08-01

    Trunk neural crest cells delaminate from the dorsal neural tube as an uninterrupted sheet; however, they convert into segmentally organized streams before migrating through the somitic territory. These neural crest cell streams join the segmental trajectories of pathfinding spinal motor axons, suggesting that interactions between these two cell types might be important for neural crest cell migration. Here, we show that in the zebrafish embryo migration of both neural crest cells and motor axons is temporally synchronized and spatially restricted to the center of the somite, but that motor axons are dispensable for segmental neural crest cell migration. Instead, we find that muscle-specific receptor kinase (MuSK) and its putative ligand Wnt11r are crucial for restricting neural crest cell migration to the center of each somite. Moreover, we find that blocking planar cell polarity (PCP) signaling in somitic muscle cells also results in non-segmental neural crest cell migration. Using an F-actin biosensor we show that in the absence of MuSK neural crest cells fail to retract non-productive leading edges, resulting in non-segmental migration. Finally, we show that MuSK knockout mice display similar neural crest cell migration defects, suggesting a novel, evolutionarily conserved role for MuSK in neural crest migration. We propose that a Wnt11r-MuSK dependent, PCP-like pathway restricts neural crest cells to their segmental path.

  20. Wnt/Ca2+ signaling pathway: a brief overview

    Institute of Scientific and Technical Information of China (English)

    Antara De

    2011-01-01

    The non-canonical Wnt/Ca2+ signaling cascade is less characterized than their canonical counterpart,the Wnt/β-catenin pathway.The non-canonical Wnt signaling pathways are diverse,defined as planer cell polarity pathway,Wnt-RAP1 signaling pathway,Wnt-Ror2 signaling pathway,Wnt-PKA pathway,Wnt-GSK3MT pathway,Wnt-aPKC pathway,Wnt-RYK pathway,Wnt-mTOR pathway,and Wnt/calcium signaling pathway.All these pathways exhibit a considerable degree of overlap between them.The Wnt/Ca2+ signaling pathway was deciphered as a crucial mediator in development.However,now there is substantial evidence that the signaling cascade is involved in many other molecular phenomena.Many aspects of Wnt/Ca2+ pathway are yet enigmatic.This review will give a brief overview of the fundamental and evolving concepts of the Wnt/Ca2+ signaling pathway.

  1. Wnt Signaling Cascades and the Roles of Syndecan Proteoglycans

    DEFF Research Database (Denmark)

    Pataki, Csilla A; Couchman, John R; Brábek, Jan

    2015-01-01

    Wnt signaling comprises a group of pathways emanating from the extracellular environment through cell-surface receptors into the intracellular milieu. Wnt signaling cascades can be divided into two main branches, the canonical/β-catenin pathway and the non-canonical pathways containing the Wnt....../planar cell polarity and Wnt/calcium signaling. Syndecans are type I transmembrane proteoglycans with a long evolutionary history, being expressed in all Bilateria and in almost all cell types. Both Wnt pathways have been extensively studied over the past 30 years and shown to have roles during development...

  2. A review of the evidence for the canonical Wnt pathway in autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Kalkman Hans

    2012-10-01

    Full Text Available Abstract Microdeletion and microduplication copy number variations are found in patients with autism spectrum disorder and in a number of cases they include genes that are involved in the canonical Wnt signaling pathway (for example, FZD9, BCL9 or CDH8. Association studies investigating WNT2, DISC1, MET, DOCK4 or AHI1 also provide evidence that the canonical Wnt pathway might be affected in autism. Prenatal medication with sodium-valproate or antidepressant drugs increases autism risk. In animal studies, it has been found that these medications promote Wnt signaling, including among others an increase in Wnt2 gene expression. Notably, the available genetic information indicates that not only canonical Wnt pathway activation, but also inhibition seems to increase autism risk. The canonical Wnt pathway plays a role in dendrite growth and suboptimal activity negatively affects the dendritic arbor. In principle, this provides a logical explanation as to why both hypo- and hyperactivity may generate a similar set of behavioral and cognitive symptoms. However, without a validated biomarker to stratify for deviant canonical Wnt pathway activity, it is probably too dangerous to treat patients with compounds that modify pathway activity.

  3. Non-Canonical Wnt Predominates in Activated Rat Hepatic Stellate Cells, Influencing HSC Survival and Paracrine Stimulation of Kupffer Cells.

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    Laura Corbett

    Full Text Available The Wnt system is highly complex and is comprised of canonical and non-canonical pathways leading to the activation of gene expression. Our aim was to examine changes in the expression of Wnt ligands and regulators during hepatic stellate cell (HSC transdifferentiation and assess the relative contributions of the canonical and non-canonical Wnt pathways in fibrogenic activated HSC. The expression profile of Wnt ligands and regulators in HSC was not supportive for a major role for β-catenin-dependent canonical Wnt signalling, this verified by inability to induce Topflash reporter activity in HSC even when expressing a constitutive active β-catenin. We detected expression of Wnt5a in activated HSC which can signal via non-canonical mechanisms and showed evidence for non-canonical signalling in these cells involving phosphorylation of Dvl2 and pJNK. Stimulation of HSC or Kupffer cells with Wnt5a regulated HSC apoptosis and expression of TGF-β1 and MCP1 respectively. We were unable to confirm a role for β-catenin-dependent canonical Wnt in HSC and instead propose autocrine and paracrine functions for Wnts expressed by activated HSC via non-canonical pathways. The data warrant detailed investigation of Wnt5a in liver fibrosis.

  4. Aberrant regulation of Wnt signaling in hepatocellular carcinoma

    Science.gov (United States)

    Liu, Li-Juan; Xie, Shui-Xiang; Chen, Ya-Tang; Xue, Jing-Ling; Zhang, Chuan-Jie; Zhu, Fan

    2016-01-01

    Hepatocellular carcinoma (HCC) is one of the most lethal malignancies in the world. Several signaling pathways, including the wingless/int-1 (Wnt) signaling pathway, have been shown to be commonly activated in HCC. The Wnt signaling pathway can be triggered via both catenin β1 (CTNNB1)-dependent (also known as “canonical”) and CTNNB1-independent (often referred to as “non-canonical”) pathways. Specifically, the canonical Wnt pathway is one of those most frequently reported in HCC. Aberrant regulation from three complexes (the cell-surface receptor complex, the cytoplasmic destruction complex and the nuclear CTNNB1/T-cell-specific transcription factor/lymphoid enhancer binding factor transcriptional complex) are all involved in HCC. Although the non-canonical Wnt pathway is rarely reported, two main non-canonical pathways, Wnt/planar cell polarity pathway and Wnt/Ca2+ pathway, participate in the regulation of hepatocarcinogenesis. Interestingly, the canonical Wnt pathway is antagonized by non-canonical Wnt signaling in HCC. Moreover, other signaling cascades have also been demonstrated to regulate the Wnt pathway through crosstalk in HCC pathogenesis. This review provides a perspective on the emerging evidence that the aberrant regulation of Wnt signaling is a critical mechanism for the development of HCC. Furthermore, crosstalk between different signaling pathways might be conducive to the development of novel molecular targets of HCC. PMID:27672271

  5. Regulation of NMDA-receptor synaptic transmission by Wnt signaling

    Science.gov (United States)

    Cerpa, Waldo; Gambrill, Abigail; Inestrosa, Nibaldo C.; Barria, Andres

    2011-01-01

    Wnt ligands are secreted glycoproteins controlling gene expression and cytoskeleton reorganization involved in embryonic development of the nervous system. However, their role in later stages of brain development, particularly in the regulation of established synaptic connections is not known. We found that Wnt-5a acutely and specifically up-regulates synaptic NMDAR currents in rat hippocampal slices facilitating induction of LTP, a cellular model of learning and memory. This effect requires an increase in postsynaptic Ca2+ and activation of non-canonical downstream effectors of the Wnt signaling pathway. In contrast, Wnt-7a, an activator of the canonical Wnt signaling pathway, has no effect on NMDAR mediated synaptic transmission. Moreover, endogenous Wnt ligands are necessary to maintain basal NMDAR synaptic transmission adjusting the threshold for synaptic potentiation. This novel role for Wnt ligands provides a mechanism for Wnt signaling to acutely modulate synaptic plasticity and brain function in later stages of development and in the mature organism. PMID:21715611

  6. Polycomb group genes Psc and Su(z)2 restrict follicle stem cell self-renewal and extrusion by controlling canonical and noncanonical Wnt signaling.

    Science.gov (United States)

    Li, Xinghua; Han, Yue; Xi, Rongwen

    2010-05-01

    Stem cells are critical for maintaining tissue homeostasis and are commonly governed by their niche microenvironment, although the intrinsic mechanisms controlling their multipotency are poorly understood. Polycomb group (PcG) genes are epigenetic silencers, and have emerged recently as important players in maintaining stem cell multipotency by preventing the initiation of differentiation programs. Here we describe an unexpected role of specific PcG genes in allowing adult stem cell differentiation and preventing stem cell-derived tumor development. We show that Posterior sex combs (Psc), which encodes a core Polycomb-repressive complex 1 (PRC1) component, functions redundantly with a similar gene, Suppressor of zeste two [Su(z)2], to restrict follicle stem cell (FSC) self-renewal in the Drosophila ovary. FSCs carrying deletion mutations of both genes extrude basally from the epithelium and continue to self-propagate at ectopic sites, leading to the development of FSC-like tumors. Furthermore, we show that the propagation of the mutant cells is driven by sustained activation of the canonical Wnt signaling pathway, which is essential for FSC self-renewal, whereas the epithelial extrusion is mediated through the planar cell polarity pathway. This study reveals a novel mechanism of epithelial extrusion, and indicates a novel role of polycomb function in allowing adult stem cell differentiation by antagonizing self-renewal programs. Given evolutionary conservation of PcG genes from Drosophila to mammals, they could have similar functions in mammalian stem cells and cancer.

  7. Neuronal development and axon growth are altered by glyphosate through a WNT non-canonical signaling pathway.

    Science.gov (United States)

    Coullery, Romina P; Ferrari, María E; Rosso, Silvana B

    2016-01-01

    The growth and morphological differentiation of neurons are critical events in the establishment of proper neuronal connectivity and functioning. The developing nervous system is highly susceptible to damage caused by exposure to environmental contaminants. Glyphosate-containing herbicides are the most used agrochemicals in the world, particularly on genetically modified plants. Previous studies have demonstrated that glyphosate induces neurotoxicity in mammals. Therefore, its action mechanism on the nervous system needs to be determined. In this study, we report about impaired neuronal development caused by glyphosate exposure. Particularly, we observed that the initial axonal differentiation and growth of cultured neurons is affected by glyphosate since most treated cells remained undifferentiated after 1 day in culture. Although they polarized at 2 days in vitro, they elicited shorter and unbranched axons and they also developed less complex dendritic arbors compared to controls. To go further, we attempted to identify the cellular mechanism by which glyphosate affected neuronal morphology. Biochemical approaches revealed that glyphosate led to a decrease in Wnt5a level, a key factor for the initial neurite development and maturation, as well as inducing a down-regulation of CaMKII activity. This data suggests that the morphological defects would likely be a consequence of the decrease in both Wnt5a expression and CaMKII activity induced by glyphosate. Additionally, these changes might be reflected in a subsequent neuronal dysfunction. Therefore, our findings highlight the importance of establishing rigorous control on the use of glyphosate-based herbicides in order to protect mammals' health.

  8. WNT signaling in neuronal maturation and synaptogenesis

    Science.gov (United States)

    Rosso, Silvana B.; Inestrosa, Nibaldo C.

    2013-01-01

    The Wnt signaling pathway plays a role in the development of the central nervous system and growing evidence indicates that Wnts also regulates the structure and function of the adult nervous system. Wnt components are key regulators of a variety of developmental processes, including embryonic patterning, cell specification, and cell polarity. In the nervous system, Wnt signaling also regulates the formation and function of neuronal circuits by controlling neuronal differentiation, axon outgrowth and guidance, dendrite development, synaptic function, and neuronal plasticity. Wnt factors can signal through three very well characterized cascades: canonical or β-catenin pathway, planar cell polarity pathway and calcium pathway that control different processes. However, divergent downstream cascades have been identified to control neuronal morphogenesis. In the nervous system, the expression of Wnt proteins is a highly controlled process. In addition, deregulation of Wnt signaling has been associated with neurodegenerative diseases. Here, we will review different aspects of neuronal and dendrite maturation, including spinogenesis and synaptogenesis. Finally, the role of Wnt pathway components on Alzheimer’s disease will be revised. PMID:23847469

  9. WNT signalling in neuronal maturation and synaptogenesis

    Directory of Open Access Journals (Sweden)

    Silvana Beatriz Rosso

    2013-07-01

    Full Text Available The Wnt signaling pathway plays a role in the development of the central nervous system (CNS and growing evidence indicates that Wnts also regulates the structure and function of the adult nervous system. Wnt components are key regulators of a variety of developmental processes, including embryonic patterning, cell specification, and cell polarity. In the nervous system, Wnt signaling also regulates the formation and function of neuronal circuits by controlling neuronal differentiation, axon outgrowth and guidance, dendrite development, synaptic function and neuronal plasticity. Wnt factors can signal through three very well characterized cascades: canonical or β-catenin pathway, planar cell polarity pathway and calcium pathway that control different processes. However, divergent downstream cascades have been identified to control neuronal morphogenesis. In the nervous system, the expression of Wnt proteins is a highly controlled process. In addition, deregulation of Wnt signaling has been associated with neurodegenerative diseases. Here, we will review different aspects of neuronal and dendrite maturation, including spinogenesis and synaptogenesis. Finally, the role of Wnt pathway components on Alzheimer’s disease will be revised.

  10. Wnt signaling in cardiovascular physiology.

    Science.gov (United States)

    Marinou, K; Christodoulides, C; Antoniades, C; Koutsilieris, M

    2012-12-01

    Wnt signaling pathways play a key role in cardiac development, angiogenesis, and cardiac hypertrophy; emerging evidence suggests that they are also involved in the pathophysiology of atherosclerosis. Specifically, an important role for Wnts has been described in the regulation of endothelial inflammation, vascular calcification, and mesenchymal stem cell differentiation. Wnt signaling also induces monocyte adhesion to endothelial cells and is crucial for the regulation of vascular smooth-muscle cell (VSMC) behavior. We discuss how the Wnt pathways are implicated in vascular biology and outline the role of Wnt signaling in atherosclerosis. Dissecting Wnt pathways involved in atherogenesis and cardiovascular disease may provide crucial insights into novel mechanisms with therapeutic potential for atherosclerosis.

  11. Wnt signaling regulates multipolar-to-bipolar transition of migrating neurons in the cerebral cortex.

    Science.gov (United States)

    Boitard, Michael; Bocchi, Riccardo; Egervari, Kristof; Petrenko, Volodymyr; Viale, Beatrice; Gremaud, Stéphane; Zgraggen, Eloisa; Salmon, Patrick; Kiss, Jozsef Z

    2015-03-03

    The precise timing of pyramidal cell migration from the ventricular germinal zone to the cortical plate is essential for establishing cortical layers, and migration errors can lead to neurodevelopmental disorders underlying psychiatric and neurological diseases. Here, we report that Wnt canonical as well as non-canonical signaling is active in pyramidal precursors during radial migration. We demonstrate using constitutive and conditional genetic strategies that transient downregulation of canonical Wnt/β-catenin signaling during the multipolar stage plays a critical role in polarizing and orienting cells for radial migration. In addition, we show that reduced canonical Wnt signaling is triggered cell autonomously by time-dependent expression of Wnt5A and activation of non-canonical signaling. We identify ephrin-B1 as a canonical Wnt-signaling-regulated target in control of the multipolar-to-bipolar switch. These findings highlight the critical role of Wnt signaling activity in neuronal positioning during cortical development.

  12. Heterotrimeric G-protein, Gα16, is a critical downstream effector of non-canonical Wnt signaling and a potent inhibitor of transformed cell growth in non small cell lung cancer.

    Directory of Open Access Journals (Sweden)

    Sreedevi Avasarala

    Full Text Available G-protein-coupled receptors (GPCR are the largest family of cell surface molecules that play important role/s in a number of biological and pathological processes including cancers. Earlier studies have highlighted the importance of Wnt7a signaling via its cognate receptor Frizzled9, a GPCR, in inhibition of cell proliferation, anchorage-independent growth, and reversal of transformed phenotype in non small cell lung cancer primarily through activation of the tumor suppressor, PPARγ. However, the G-protein effectors that couple to this important tumor suppressor pathway have not been identified, and are of potential therapeutic interest. In this study, by using two independent Wnt7a/Frizzled9-specific read-outs, we identify Gα16 as a novel downstream effector of Wnt7a/Frizzled9 signaling. Interestingly, Gα16 expression is severely down-regulated, both at the messenger RNA levels and protein levels, in many non small cell lung cancer cell lines. Additionally, through gene-specific knock-downs and expression of GTPase-deficient forms (Q212L of Gα16, we also establish Gα16 as a novel regulator of non small cell lung cancer cell proliferation and anchorage-independent cell growth. Taken together, our data not only establish the importance of Gα16 as a critical downstream effector of the non-canonical Wnt signaling pathway but also as a potential therapeutic target for the treatment of non small cell lung cancer.

  13. CaSR function in the intestine: Hormone secretion, electrolyte absorption and secretion, paracrine non-canonical Wnt signaling and colonic crypt cell proliferation.

    Science.gov (United States)

    Macleod, R John

    2013-06-01

    Expression and function of the CaSR have been shown in some mammalian taste buds and basal cells of the esophagus. Signaling cascades responsible for CaSR-mediated stimulation of H(+)-K(+)-ATPase on human parietal cells have been defined. Transgenic mice and reductionistic cell culture models have shown that the CaSR promotes gastrin secretion from G cells, cholecystokinin (CCK) secretion from duodenal I cells and BMP-2 secretion from sub-epithelial myofibroblasts. In addition, the CaSR mediates a novel paracrine relationship between myofibroblasts and overlying epithelial cells in the colon. Thus, CaSR activators stimulate secretion of Wnt5a from myofibroblasts and expression of the Wnt5a receptor Ror2 in epithelial cells. CaSR-mediated Wnt5a/Ror2 engagement stimulates epithelial differentiation and reduces expression of the receptor for tumor necrosis factor (TNFR1). CaSR activators also modulate intestinal motility, inhibit Cl(-) secretion and stimulate Na(+) absorption in both the small intestine and colon. Colonic epithelia from conditional and global CaSR knockout mice exhibit increased proliferation with increased Wnt/β-catenin signaling, demonstrating that the CaSR negatively modulates colonic epithelial growth.

  14. Antagonizing canonical Wnt signaling pathway by recombinant human sFRP4 purified from E. coli and its implications in cancer therapy.

    Science.gov (United States)

    Ghoshal, Archita; Ghosh, Siddhartha Sankar

    2016-07-01

    The Wnt signaling pathway plays a predominant role in aberrant proliferation in myriad of cancers. In non-cancerous cells, Wnts are blocked by the secreted frizzled-related proteins (sFRPs) that are generally downregulated in cancer cells. We have purified and characterized bacterially expressed glutathione S-transferase-tagged SFRP4 from a novel clone generated from human cell origin. Cervical cancer (HeLa) and lung cancer (A549) cells, in which Wnt and associated genes were found to be expressed, were treated with the purified recombinant sFRP4, which revealed a significant dose-dependent cell growth inhibition up to 40 %. The current investigation on functionality of this bacterially produced recombinant sFRP4 in arresting cancer cell proliferation is the first of its kind, where G2/M phase arrest and early apoptosis were evident. Increase in phosphorylated β-catenin in sFRP4 treatment indicated inhibition of Wnt pathway, which was further confirmed by downregulation of pro-proliferative genes, namely cyclin D1, c-myc, and survivin. Functional activity of recombinant sFRP4 was further exploited in co-therapy module with chemotherapeutic drugs to decipher molecular events. Collectively, our study on purified recombinant sFRP4 from bacterial host holds great promise in targeting Wnt signaling for exploring new strategies to combat cancer.

  15. Zebrafish colgate/hdac1 functions in the non-canonical Wnt pathway during axial extension and in Wnt-independent branchiomotor neuron migration.

    Science.gov (United States)

    Nambiar, Roopa M; Ignatius, Myron S; Henion, Paul D

    2007-01-01

    Vertebrate gastrulation involves the coordinated movements of populations of cells. These movements include cellular rearrangements in which cells polarize along their medio-lateral axes leading to cell intercalations that result in elongation of the body axis. Molecular analysis of this process has implicated the non-canonical Wnt/Frizzled signaling pathway that is similar to the planar cell polarity pathway (PCP) in Drosophila. Here we describe a zebrafish mutant, colgate (col), which displays defects in the extension of the body axis and the migration of branchiomotor neurons. Activation of the non-canonical Wnt/PCP pathway in these mutant embryos by overexpressing DeltaNdishevelled, rho kinase2 and van gogh-like protein 2 (vangl2) rescues the extension defects suggesting that col acts as a positive regulator of the non-canonical Wnt/PCP pathway. Further, we show that col normally regulates the caudal migration of nVII facial hindbrain branchiomotor neurons and that the mutant phenotype can be rescued by misexpression of vangl2 independent of the Wnt/PCP pathway. We cloned the col locus and found that it encodes histone deacetylase1 (hdac1). Our previous results and studies by others have implicated hdac1 in repressing the canonical Wnt pathway. Here, we demonstrate novel roles for zebrafish hdac1 in activating non-canonical Wnt/PCP signaling underlying axial extension and in promoting Wnt-independent caudal migration of a subset of hindbrain branchiomotor neurons.

  16. A review of 1α,25(OH)2D3 dependent Pdia3 receptor complex components in Wnt5a non-canonical pathway signaling.

    Science.gov (United States)

    Doroudi, Maryam; Olivares-Navarrete, Rene; Boyan, Barbara D; Schwartz, Zvi

    2015-08-01

    Wnt5a and 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] regulate endochondral ossification. 1α,25(OH)2D3 initiates its calcium-dependent effects via its membrane-associated receptor, protein disulfide isomerase A3 (Pdia3). 1α,25(OH)2D3 binding to Pdia3 triggers the interaction between Pdia3 and phospholipase A2 (PLA2)-activating protein (PLAA), resulting in downstream activation of calcium/calmodulin-dependent protein kinase II (CaMKII), PLA2, and protein kinase C (PKC). Wnt5a initiates its calcium-dependent effects via binding its receptors Frizzled2 (FZD2) and Frizzled5 (FZD5) and receptor tyrosine kinase-like orphan receptor 2 (ROR2), activating intracellular calcium release and stimulating PKC and CaMKII. Recent efforts to determine the inter-relation between Wnt5a and 1α,25(OH)2D3 signaling pathways have demonstrated that Wnt5a signals through a CaMKII/PLA2/PGE2/PKC cascade in chondrocytes and osteoblasts in which the components of the Pdia3 receptor complex were required. Furthermore, ROR2, but not FZD2 or FZD5, was required to mediate the calcium-dependent actions of 1α,25(OH)2D3. This review provides evidence that 1α,25(OH)2D3 and Wnt5a mediate their calcium-dependent pathways via similar receptor components and proposes that these pathways may interact since they are competing for the same receptor complex components.

  17. Influence of canonical Wnt signaling pathway on the occurrence and development of ovarian cancer%经典Wnt信号通路对卵巢癌发生发展的影响

    Institute of Scientific and Technical Information of China (English)

    刘翠莲; 崔澂; 王利飞; 郝淑维

    2014-01-01

    经典Wnt信号通路是近几年来卵巢癌发生相关信号通路研究的热点,激活后可诱导卵巢癌干细胞增殖及自我更新、存活及转移,其主要成员靶基因突变及传导通路负性调控分子异常表达与卵巢癌发生发展密切相关.深入了解经典Wnt信号通路在卵巢癌中的调控机制,并以此为抗卵巢癌治疗靶点进行基础研究及临床前期实验,可为临床更好地治疗卵巢癌提供理论依据.%The canonical Wnt signaling pathway has been the hot spot in the signaling pathway studies which are related to ovary carcinogenesis in recent years,whose activation may induce the multiplication and self-renewal,survival and metastasis of ovarian cancer stem cells.The target gene mutations of key members in the canonical Wnt pathway and abnormal expresses of negative regulation molecules are closely associated with the occurrence and development of ovarian cancer.Deeply investigating the regulative mechanisms of canonical Wnt signaling pathway in ovarian cancer,and taking this as the therapeutic target to conduct the basic research and preclinical experiment may provide theoretical basis for treating better ovarian cancer patients in clinical practice.

  18. Mesodiencephalic Dopaminergic Neuronal Differentiation Does Not Involve GLI2A-Mediated SHH-Signaling and Is under the Direct Influence of Canonical WNT Signaling

    NARCIS (Netherlands)

    Mesman, S.; von Oerthel, L.; Smidt, M.P.

    2014-01-01

    Sonic Hedgehog (SHH) and WNT proteins are key regulators in many developmental processes, like embryonic patterning and brain development. In the brain, SHH is expressed in a gradient starting in the floor plate (FP) progressing ventrally in the midbrain, where it is thought to be involved in the de

  19. Matrix metalloproteinase-10 regulates stemness of ovarian cancer stem-like cells by activation of canonical Wnt signaling and can be a target of chemotherapy-resistant ovarian cancer

    Science.gov (United States)

    Mariya, Tasuku; Hirohashi, Yoshihiko; Torigoe, Toshihiko; Tabuchi, Yuta; Asano, Takuya; Saijo, Hiroshi; Kuroda, Takafumi; Yasuda, Kazuyo; Mizuuchi, Masahito; Saito, Tsuyoshi; Sato, Noriyuki

    2016-01-01

    Epithelial ovarian cancer (EOC) is one of the most lethal cancers in females. Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) have been reported to be origin of primary and recurrent cancers and to be resistant to several treatments. In this study, we identified matrix metalloproteinase-10 (MMP10) is expressed in CSCs/CICs of EOC. An immunohistochemical study revealed that a high expression level of MMP10 is a marker for poor prognosis and platinum resistance in multivariate analysis. MMP10 gene overexpression experiments and MMP10 gene knockdown experiments using siRNAs revealed that MMP10 has a role in the maintenance of CSCs/CICs in EOC and resistance to platinum reagent. Furthermore, MMP10 activate canonical Wnt signaling by inhibiting noncanonical Wnt signaling ligand Wnt5a. Therefore, MMP10 is a novel marker for CSCs/CICs in EOC and that targeting MMP10 is a novel promising approach for chemotherapy-resistant CSCs/CICs in EOC. PMID:27072580

  20. Interactions between PPAR Gamma and the Canonical Wnt/Beta-Catenin Pathway in Type 2 Diabetes and Colon Cancer

    Science.gov (United States)

    Claes, Victor

    2017-01-01

    In both colon cancer and type 2 diabetes, metabolic changes induced by upregulation of the Wnt/beta-catenin signaling and downregulation of peroxisome proliferator-activated receptor gamma (PPAR gamma) may help account for the frequent association of these two diseases. In both diseases, PPAR gamma is downregulated while the canonical Wnt/beta-catenin pathway is upregulated. In colon cancer, upregulation of the canonical Wnt system induces activation of pyruvate dehydrogenase kinase and deactivation of the pyruvate dehydrogenase complex. As a result, a large part of cytosolic pyruvate is converted into lactate through activation of lactate dehydrogenase. Lactate is extruded out of the cell by means of activation of monocarboxylate lactate transporter-1. This phenomenon is called Warburg effect. PPAR gamma agonists induce beta-catenin inhibition, while inhibition of the canonical Wnt/beta-catenin pathway activates PPAR gamma.

  1. Wnt pathway in Dupuytren disease: connecting profibrotic signals.

    Science.gov (United States)

    van Beuge, Marike M; Ten Dam, Evert-Jan P M; Werker, Paul M N; Bank, Ruud A

    2015-12-01

    A role of Wnt signaling in Dupuytren disease, a fibroproliferative disease of the hand and fingers, has not been fully elucidated. We examined a large set of Wnt pathway components and signaling targets and found significant dysregulation of 41 Wnt-related genes in tissue from the Dupuytren nodules compared with patient-matched control tissue. A large proportion of genes coding for Wnt proteins themselves was downregulated. However, both canonical Wnt targets and components of the noncanonical signaling pathway were upregulated. Immunohistochemical analysis revealed that protein expression of Wnt1-inducible secreted protein 1 (WISP1), a known Wnt target, was increased in nodules compared with control tissue, but knockdown of WISP1 using small interfering RNA (siRNA) in the Dupuytren myofibroblasts did not confirm a functional role. The protein expression of noncanonical pathway components Wnt5A and VANGL2 as well as noncanonical coreceptors Ror2 and Ryk was increased in nodules. On the contrary, the strongest downregulated genes in this study were 4 antagonists of Wnt signaling (DKK1, FRZB, SFRP1, and WIF1). Downregulation of these genes in the Dupuytren tissue was mimicked in vitro by treating normal fibroblasts with transforming growth factor β1 (TGF-β1), suggesting cross talk between different profibrotic pathways. Furthermore, siRNA-mediated knockdown of these antagonists in normal fibroblasts led to increased nuclear translocation of Wnt target β-catenin in response to TGF-β1 treatment. In conclusion, we have shown extensive dysregulation of Wnt signaling in affected tissue from Dupuytren disease patients. Components of both the canonical and the noncanonical pathways are upregulated, whereas endogenous antagonists are downregulated, possibly via interaction with other profibrotic pathways.

  2. Impaired Telomere Maintenance and Decreased Canonical WNT Signaling but Normal Ribosome Biogenesis in Induced Pluripotent Stem Cells from X-Linked Dyskeratosis Congenita Patients.

    Directory of Open Access Journals (Sweden)

    Bai-Wei Gu

    from human patients have so far not shown defects in pseudouridylation or ribosomal RNA processing. None of the mutant iPS cells presented here show decreased pseudouridine levels in rRNA or defective rRNA processing suggesting telomere maintenance defects account for most of the phenotype of X-linked DC. Finally gene expression analysis of the iPS cells shows that WNT signaling is significantly decreased in all mutant cells, raising the possibility that defective WNT signaling may contribute to disease pathogenesis.

  3. Activation of non-canonical Wnt/JNK pathway by Wnt3a is associated with differentiation fate determination of human bone marrow stromal (mesenchymal) stem cells

    DEFF Research Database (Denmark)

    Qiu, Weimin; Chen, Li; Kassem, Moustapha

    2011-01-01

    The canonical Wnt signaling pathway can determine human bone marrow stromal (mesenchymal) stem cell (hMSC) differentiation fate into osteoblast or adipocyte lineages. However, its downstream targets in MSC are not well characterized. Thus, using DNA microarrays, we compared global gene expression...

  4. Evaluating the Role of Wnt Signal Transduction in Promoting the Development of the Heart

    Directory of Open Access Journals (Sweden)

    Leonard M. Eisenberg

    2007-01-01

    Full Text Available Wnts are a family of secreted signaling proteins that are encoded by 19 distinct genes in the vertebrate genome. These molecules initiate several signal transduction pathways: the canonical Wnt, Wnt/Ca2+, and Wnt/planar cell polarity pathways. Wnt proteins have major impact on embryonic development, tumor progression, and stem cell differentiation. Wnt signal transduction also influences the formation of the heart, yet many issues concerning the involvement of Wnt regulation in initiating cardiac development remain unresolved. In this review, we will examine the published record to discern (a what has been shown by experimental studies on the participation of Wnt signaling in cardiogenesis, and (b what are the important questions that need to be addressed to understand the importance and function of Wnt signal transduction in facilitating the development of the heart.

  5. Alzheimer Disease: Crosstalk between the Canonical Wnt/Beta-Catenin Pathway and PPARs Alpha and Gamma

    Science.gov (United States)

    Vallée, Alexandre; Lecarpentier, Yves

    2016-01-01

    The molecular mechanisms underlying the pathophysiology of Alzheimer's disease (AD) are still not fully understood. In AD, Wnt/beta-catenin signaling has been shown to be downregulated while the peroxisome proliferator-activated receptor (PPAR) gamma (mARN and protein) is upregulated. Certain neurodegenerative diseases share the same Wnt/beta-catenin/PPAR gamma profile, such as bipolar disorder and schizophrenia. Conversely, other NDs share an opposite profile, such as amyotrophic lateral sclerosis, Parkinson's disease, Huntington's disease, multiple sclerosis, and Friedreich's ataxia. AD is characterized by the deposition of extracellular Abeta plaques and the formation of intracellular neurofibrillary tangles in the central nervous system (CNS). Activation of Wnt signaling or inhibition of both glycogen synthase kinase-3beta and Dickkopf 1, two key negative regulators of the canonical Wnt pathway, are able to protect against Abeta neurotoxicity and to ameliorate cognitive performance in AD patients. Although PPAR gamma is upregulated in AD patients, and despite the fact that it has been shown that the PPAR gamma and Wnt/beta catenin pathway systems work in an opposite manner, PPAR gamma agonists diminish learning and memory deficits, decrease Abeta activation of microglia, and prevent hippocampal and cortical neurons from dying. These beneficial effects observed in AD transgenic mice and patients might be partially due to the anti-inflammatory properties of PPAR gamma agonists. Moreover, activation of PPAR alpha upregulates transcription of the alpha-secretase gene and represents a new therapeutic treatment for AD. This review focuses largely on the behavior of two opposing pathways in AD, namely Wnt/beta-catenin signaling and PPAR gamma. It is hoped that this approach may help to develop novel AD therapeutic strategies integrating PPAR alpha signaling.

  6. 间充质干细胞增殖、衰老及分化:Wnt信号通路经典与非经典的调控作用%Proliferation, senescence and differentiation of mesenchymal stem cells:canonical and non-canonical regulations of Wnt signaling pathway

    Institute of Scientific and Technical Information of China (English)

    施剑明; 邬亚华; 耿书国; 殷明

    2014-01-01

    背景:间充质干细胞作为再生医学及组织工程领域中的重要种子细胞来源,对其不同生物学特性的调控机制一直是目前研究的热点。  目的:综述Wnt信号通路调控间充质干细胞增殖、衰老及分化的研究进展。  方法:应用计算机检索2002至2014年PubMed数据库及CNKI数据库,以“mesenchymal stem cel s, Wnt signaling pathway,proliferation,senescence,differentiation”或“间充质干细胞,Wnt信号通路,增殖,衰老,分化”为关键词进行检索,重点对44篇文章进行分析。  结果与结论:Wnt信号通路广泛参与调控间充质干细胞多种生物学特性。经典Wnt信号通路对间充质干细胞增殖及向成骨细胞分化具有双向调控作用,并能够促进其衰老及向神经细胞分化,抑制其向脂肪细胞分化;非经典Wnt信号通路则参与促进间充质干细胞衰老及向成骨细胞分化,抑制其增殖及向脂肪细胞分化,不参与其向神经细胞分化,为其应用于骨组织工程、神经损伤修复等领域提供了新的研究靶点。%BACKGROUND:As mesenchymal stem cells are commonly used as seed cells in studies of regenerative medicine and tissue engineering, the regulatory mechanism of their biological characteristics is a current research focus. OBJECTIVE:To summarize the regulations of Wnt signaling pathway on proliferation, senescence and differentiation of mesenchymal stem cells. METHODS:PubMed database and CNKI database were retrieved by computer using the key words of“mesenchymal stem cells, Wnt signaling pathway, proliferation, senescence, differentiation”in Chinese and English, respectively, between 2002 and 2014. Final y, 44 articles were included in result analysis. RESULTS AND CONCLUSION:Wnt signaling pathway is widely involved in the regulations of the biological characteristics of mesenchymal stem cells. Canonical Wnt signaling pathway reveals a bi

  7. Components of the canonical and non-canonical Wnt pathways are not mis-expressed in pituitary tumors.

    Directory of Open Access Journals (Sweden)

    Leandro Machado Colli

    Full Text Available INTRODUCTION: Canonical and non-canonical Wnt pathways are involved in the genesis of multiple tumors; however, their role in pituitary tumorigenesis is mostly unknown. OBJECTIVE: This study evaluated gene and protein expression of Wnt pathways in pituitary tumors and whether these expression correlate to clinical outcome. MATERIALS AND METHODS: Genes of the WNT canonical pathway: activating ligands (WNT11, WNT4, WNT5A, binding inhibitors (DKK3, sFRP1, β-catenin (CTNNB1, β-catenin degradation complex (APC, AXIN1, GSK3β, inhibitor of β-catenin degradation complex (AKT1, sequester of β-catenin (CDH1, pathway effectors (TCF7, MAPK8, NFAT5, pathway mediators (DVL-1, DVL-2, DVL-3, PRICKLE, VANGL1, target genes (MYB, MYC, WISP2, SPRY1, TP53, CCND1; calcium dependent pathway (PLCB1, CAMK2A, PRKCA, CHP; and planar cell polarity pathway (PTK7, DAAM1, RHOA were evaluated by QPCR, in 19 GH-, 18 ACTH-secreting, 21 non-secreting (NS pituitary tumors, and 5 normal pituitaries. Also, the main effectors of canonical (β-catenin, planar cell polarity (JNK, and calcium dependent (NFAT5 Wnt pathways were evaluated by immunohistochemistry. RESULTS: There are no differences in gene expression of canonical and non-canonical Wnt pathways between all studied subtypes of pituitary tumors and normal pituitaries, except for WISP2, which was over-expressed in ACTH-secreting tumors compared to normal pituitaries (4.8x; p = 0.02, NS pituitary tumors (7.7x; p = 0.004 and GH-secreting tumors (5.0x; p = 0.05. β-catenin, NFAT5 and JNK proteins showed no expression in normal pituitaries and in any of the pituitary tumor subtypes. Furthermore, no association of the studied gene or protein expression was observed with tumor size, recurrence, and progressive disease. The hierarchical clustering showed a regular pattern of genes of the canonical and non-canonical Wnt pathways randomly distributed throughout the dendrogram. CONCLUSIONS: Our data reinforce previous reports

  8. Canonical Wnt pathway inhibitor ICG-001 induces cytotoxicity of multiple myeloma cells in Wnt-independent manner.

    Directory of Open Access Journals (Sweden)

    Eileen R Grigson

    Full Text Available Canonical Wnt signaling has been implicated in the regulation of multiple myeloma (MM growth. Here, we investigated whether the targeting of this pathway with a novel pharmacological inhibitor ICG-001 would result in an anti-tumor effect and improvement of chemosensitivity in MM. As expected, ICG-001 specifically down-regulated β-catenin/TCF-mediated transcription in MM cells. Treatment with ICG-001 resulted in growth arrest and apoptosis in MM cell lines and primary MM cells. Moreover, ICG-001 enhanced the cytotoxic effects of doxorubicin and melphalan and abrogated chemoresistance of MM cells to these chemotherapeutics induced by bone marrow stroma. The cytotoxic effect of ICG-001 was caspase-dependent and mediated through transcriptional up-regulation of BH3-only pro-apoptotic members of the Bcl-2 family Noxa and Puma but not through inhibition of canonical Wnt signaling. ICG-001 selectively induced apoptosis in primary MM cells but did not affect non-MM cells of the bone marrow microenvironment. Experiments using a xenograft model of MM showed substantial anti-tumor effects of this compound in vivo. Thus, our study demonstrated that the small molecule inhibitor ICG-001 has strong anti-MM effects and could be developed further for therapeutic intervention in this disease.

  9. Expression of brain-derived neurotrophic factor (BDNF) is regulated by the Wnt signaling pathway

    OpenAIRE

    Yi, Hyun; Hu, Jianfei; Qian, Jiang; Hackam, Abigail S.

    2012-01-01

    BDNF is a well-characterized neurotrophin that mediates a wide variety of activities in the central nervous system (CNS), including neuronal differentiation, neuroprotection and synaptic plasticity. The canonical Wnt signaling pathway is a critical regulator of embryonic development and homeostasis in adult tissues. Our group and others recently demonstrated that Wnt signaling induces BDNF expression in neurons and glia. However, the precise relationship between BDNF and Wnt signaling pathway...

  10. Wnt signaling: the good and the bad

    Institute of Scientific and Technical Information of China (English)

    Xi Chen; Jun Yang; Paul M Evans; Chunming Liu

    2008-01-01

    Since the first Wnt gene was identified in 1982,the functions and mechanisms of Wnt signaling have been extensively studied.Wnt signaling is conserved from invertebrates to vertebrates and regulates early embryonic development as well as the homeostasis of adult tissues.In addition,both embryonic stem cells and adult stem cells are regulated by Wnt signaling.Deregulation of Wnt signaling is associated with many human diseases,particularly cancers.In this review,we will discuss in detail the functions of many components involved in the Wnt signal transduction pathway.Then,we will explore what is known about the role of Wnt signaling in stem cells and cancers.

  11. Wnt and planar cell polarity signaling in cystic renal disease.

    Science.gov (United States)

    Goggolidou, Paraskevi

    2014-01-01

    Cystic kidney diseases can cause end stage renal disease, affecting millions of individuals worldwide. They may arise early or later in life, are characterized by a spectrum of symptoms and can be caused by diverse genetic defects. The primary cilium, a microtubule-based organelle that can serve as a signaling antenna, has been demonstrated to have a significant role in ensuring correct kidney development and function. In the kidney, one of the signaling pathways that requires the cilium for normal development is Wnt signaling. In this review, the roles of primary cilia in relation to canonical and non-canonical Wnt/PCP signaling in cystic renal disease are described. The evidence of the associations between cilia, Wnt signaling and cystic renal disease is discussed and the significance of planar cell polarity-related mechanisms in cystic kidney disease is presented. Although defective Wnt signaling is not the only cause of renal disease, research is increasingly highlighting its importance, encouraging the development of Wnt-associated diagnostic and prognostic tools for cystic renal disease.

  12. Gpr177-mediated Wnt Signaling Is Required for Secondary Palate Development.

    Science.gov (United States)

    Liu, Y; Wang, M; Zhao, W; Yuan, X; Yang, X; Li, Y; Qiu, M; Zhu, X-J; Zhang, Z

    2015-07-01

    Cleft palate represents one of the major congenital birth defects in humans. Despite the essential roles of ectodermal canonical Wnt and mesenchymal Wnt signaling in the secondary palate development, the function of mesenchymal canonical Wnt activity in secondary palate development remains elusive. Here we show that Gpr177, a highly conserved transmembrane protein essential for Wnt trafficking, is required for secondary palate development. Gpr177 is expressed in both epithelium and mesenchyme of palatal shelves during mouse development. Wnt1(Cre)-mediated deletion of Gpr177 in craniofacial neural crest cells leads to a complete cleft secondary palate, which is formed mainly due to aberrant cell proliferation and increased cell death in palatal shelves. By BATGAL staining, we reveal an intense canonical Wnt activity in the anterior palate mesenchyme of E12.5 wild-type embryos but not in Gpr177(Wnt1-Cre) embryos, suggesting that mesenchymal canonical Wnt signaling activated by Gpr177-mediated mesenchymal Wnts is critical for secondary palate development. Moreover, phosphorylation of JNK and c-Jun is impaired in the Gpr177(Wnt1-Cre) palate and is restored by implantation of Wnt5a-soaked beads in the in vitro palate explants, suggesting that Gpr177 probably regulates palate development via the Wnt5a-mediated noncanonical Wnt pathway in which c-Jun and JNK are involved. Importantly, certain cellular processes and the altered gene expression in palates lacking Gpr177 are distinct from that of the Wnt5a mutant, further demonstrating involvement of other mesenchymal Wnts in the process of palate development. Together, these results suggest that mesenchymal Gpr177 is required for secondary palate development by regulating and integrating mesenchymal canonical and noncanonical Wnt signals.

  13. Wnt signaling in the murine diastema

    Science.gov (United States)

    Porntaveetus, Thantrira; Ohazama, Atsushi; Choi, Hong Y.; Herz, Joachim

    2012-01-01

    The correct number and shape of teeth are critical factors for an aesthetic and functional dentition. Understanding the molecular mechanisms regulating tooth number and shape are therefore important in orthodontics. Mice have only one incisor and three molars in each jaw quadrant that are divided by a tooth-less region, the diastema. Although mice lost teeth in the diastema during evolution, the remnants of the evolutionary lost teeth are observed as transient epithelial buds in the wild-type diastema during early stages of development. Shh and Fgf signaling pathways that are essential for tooth development have been shown to be repressed in the diastema. It remains unclear however how Wnt signaling, that is also required for tooth development, is regulated in the diastema. In this study we found that in the embryonic diastema, Wnt5a expression was observed in mesenchyme, whereas Wnt4 and Wnt10b were expressed in epithelium. The expression of Wnt6 and Wnt11 was found in both tissues. The Wnt co-receptor, Lrp6, was weakly expressed in the diastema overlapping with weak Lrp4 expression, a co-receptor that inhibits Wnt signaling. Secreted Wnt inihibitors Dkk1, Dkk2, and Dkk3 were also expressed in the diastema. Lrp4 mutant mice develop supernumerary teeth in the diastema that is accompanied by upregulation of Wnt signaling and Lrp6 expression. Wnt signaling is thus usually attenuated in the diastema by these secreted and membrane bound Wnt inhibitors. PMID:21531785

  14. Wnt Signaling in Cancer Stem Cell Biology.

    Science.gov (United States)

    de Sousa E Melo, Felipe; Vermeulen, Louis

    2016-06-27

    Aberrant regulation of Wnt signaling is a common theme seen across many tumor types. Decades of research have unraveled the epigenetic and genetic alterations that result in elevated Wnt pathway activity. More recently, it has become apparent that Wnt signaling levels identify stem-like tumor cells that are responsible for fueling tumor growth. As therapeutic targeting of these tumor stem cells is an intense area of investigation, a concise understanding on how Wnt activity relates to cancer stem cell traits is needed. This review attempts at summarizing the intricacies between Wnt signaling and cancer stem cell biology with a special emphasis on colorectal cancer.

  15. Huwe1-mediated ubiquitylation of dishevelled defines a negative feedback loop in the Wnt signaling pathway

    NARCIS (Netherlands)

    de Groot, Reinoud E A; Ganji, Ranjani S; Bernatik, Ondrej; Lloyd-Lewis, Bethan; Seipel, Katja; Šedová, Kateřina; Zdráhal, Zbyněk; Dhople, Vishnu M; Dale, Trevor C; Korswagen, Hendrik C; Bryja, Vitezslav

    2014-01-01

    Wnt signaling plays a central role in development, adult tissue homeostasis, and cancer. Several steps in the canonical Wnt/β-catenin signaling cascade are regulated by ubiquitylation, a protein modification that influences the stability, subcellular localization, or interactions of target proteins.

  16. Revisiting the role of Wnt/β-catenin signaling in prostate cancer.

    Science.gov (United States)

    Schneider, Jeffrey A; Logan, Susan K

    2017-02-09

    The androgen receptor (AR) is a widely accepted therapeutic target in prostate cancer and multiple studies indicate that the AR and Wnt/β-catenin pathways intersect. Recent genome-wide analysis of prostate cancer metastases illustrate the importance of the Wnt/β-catenin pathway in prostate cancer and compel us to reexamine the interaction of the AR and Wnt/β-catenin signaling pathways. This review includes newer areas of interest such as non-canonical Wnt signaling and the role of Wnts in prostate cancer stem cells. The effort to develop Wnt modulating therapeutics, both biologics and small molecules, is also discussed.

  17. Noncanonical Wnt signaling promotes osteoclast differentiation and is facilitated by the human immunodeficiency virus protease inhibitor ritonavir

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, Francisco [Division of Hematology-Oncology, Department of Medicine, Weill Cornell Medical College, New York, NY (United States); Oguma, Junya; Brown, Anthony M.C. [Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY (United States); Laurence, Jeffrey, E-mail: jlaurenc@med.cornell.edu [Division of Hematology-Oncology, Department of Medicine, Weill Cornell Medical College, New York, NY (United States)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer First demonstration of direct role for noncanonical Wnt in osteoclast differentiation. Black-Right-Pointing-Pointer Demonstration of Ryk as a Wnt5a/b receptor in inhibition of canonical Wnt signaling. Black-Right-Pointing-Pointer Modulation of noncanonical Wnt signaling by a clinically important drug, ritonavir. Black-Right-Pointing-Pointer Establishes a mechanism for an important clinical problem: HIV-associated bone loss. -- Abstract: Wnt proteins that signal via the canonical Wnt/{beta}-catenin pathway directly regulate osteoblast differentiation. In contrast, most studies of Wnt-related effects on osteoclasts involve indirect changes. While investigating bone mineral density loss in the setting of human immunodeficiency virus (HIV) infection and its treatment with the protease inhibitor ritonavir (RTV), we observed that RTV decreased nuclear localization of {beta}-catenin, critical to canonical Wnt signaling, in primary human and murine osteoclast precursors. This occurred in parallel with upregulation of Wnt5a and Wnt5b transcripts. These Wnts typically stimulate noncanonical Wnt signaling, and this can antagonize the canonical Wnt pathway in many cell types, dependent upon Wnt receptor usage. We now document RTV-mediated upregulation of Wnt5a/b protein in osteoclast precursors. Recombinant Wnt5b and retrovirus-mediated expression of Wnt5a enhanced osteoclast differentiation from human and murine monocytic precursors, processes facilitated by RTV. In contrast, canonical Wnt signaling mediated by Wnt3a suppressed osteoclastogenesis. Both RTV and Wnt5b inhibited canonical, {beta}-catenin/T cell factor-based Wnt reporter activation in osteoclast precursors. RTV- and Wnt5-induced osteoclast differentiation were dependent upon the receptor-like tyrosine kinase Ryk, suggesting that Ryk may act as a Wnt5a/b receptor in this context. This is the first demonstration of a direct role for Wnt signaling pathways and Ryk in

  18. Coordination of kidney organogenesis by Wnt signaling.

    Science.gov (United States)

    Halt, Kimmo; Vainio, Seppo

    2014-04-01

    Several Wnt proteins are expressed in the embryonic kidney during various stages of development. Gene knockout models and ex vivo studies have provided strong evidence that Wnt-mediated signals are essential in renal ontogeny. Perhaps the most critical factors, Wnt9b and Wnt4, function during the early phase when the cap mesenchyme is induced to undergo morphogenesis into a nephron. Wnt11 controls early ureteric bud branching and contributes to the final kidney size. In addition to its inductive role, later on Wnt9b plays a significant role in the convergent extension of the tubular epithelial cells, while Wnt4 signaling controls smooth muscle cell fates in the medulla. Wnt7b has a specific function together with its likely antagonist Dkk1 in controlling the morphogenesis of the renal medulla. The signal-transduction mechanisms of the Wnts in kidney ontogeny have not been resolved, but studies characterizing the downstream signaling pathways are emerging. Aberrant Wnt signaling may lead to kidney diseases ranging from fatal kidney agenesis to more benign phenotypes. Wnt-mediated signaling regulates several critical aspects of kidney development from the early inductive stages to later steps of tubular epithelial maturation.

  19. Andrographolide activates the canonical Wnt signalling pathway by a mechanism that implicates the non-ATP competitive inhibition of GSK-3β: autoregulation of GSK-3β in vivo.

    Science.gov (United States)

    Tapia-Rojas, Cheril; Schüller, Andreas; Lindsay, Carolina B; Ureta, Roxana C; Mejías-Reyes, Cristóbal; Hancke, Juan; Melo, Francisco; Inestrosa, Nibaldo C

    2015-03-01

    Wnt/β-catenin signalling is an important pathway that regulates multiple biological processes, including cell adhesion and determination of cell fate during animal development; in the adult nervous system it regulates the structure and function of synapses. Wnt-signalling dysfunction is associated with several neurodegenerative diseases such as schizophrenia and Alzheimer's disease. The use of natural compounds is an interesting strategy in the search for drugs with the therapeutic potential to activate this signalling pathway. In the present study, we report that andrographolide (ANDRO), a component of Andrographis paniculata, is a potent activator of Wnt signalling. Our results indicate that ANDRO activates this pathway, inducing the transcription of Wnt target genes by a mechanism that bypasses Wnt ligand binding to its receptor. In vitro kinase assays demonstrate that ANDRO inhibits glycogen synthase kinase (GSK)-3β by a non-ATP-competitive, substrate-competitive mode of action. In silico analyses suggest that ANDRO interacts with the substrate-binding site of GSK-3β. Finally, we demonstrated that the increase seen in the levels of GSK-3β phosphorylated at Ser⁹ is the result of an autoregulatory mechanism of the kinase in vivo, although not through activation of protein phosphatase type 1. Our results suggest that ANDRO could be used as a potential therapeutic drug for disorders caused by Wnt-signalling dysfunction such as neurodegenerative diseases.

  20. Wnt Signaling Regulates Multipolar-to-Bipolar Transition of Migrating Neurons in the Cerebral Cortex

    Directory of Open Access Journals (Sweden)

    Michael Boitard

    2015-03-01

    Full Text Available The precise timing of pyramidal cell migration from the ventricular germinal zone to the cortical plate is essential for establishing cortical layers, and migration errors can lead to neurodevelopmental disorders underlying psychiatric and neurological diseases. Here, we report that Wnt canonical as well as non-canonical signaling is active in pyramidal precursors during radial migration. We demonstrate using constitutive and conditional genetic strategies that transient downregulation of canonical Wnt/β-catenin signaling during the multipolar stage plays a critical role in polarizing and orienting cells for radial migration. In addition, we show that reduced canonical Wnt signaling is triggered cell autonomously by time-dependent expression of Wnt5A and activation of non-canonical signaling. We identify ephrin-B1 as a canonical Wnt-signaling-regulated target in control of the multipolar-to-bipolar switch. These findings highlight the critical role of Wnt signaling activity in neuronal positioning during cortical development.

  1. The Wnt/planar cell polarity signaling pathway contributes to the integrity of tight junctions in brain endothelial cells

    OpenAIRE

    2013-01-01

    Wnt morphogens released by neural precursor cells were recently reported to control blood–brain barrier (BBB) formation during development. Indeed, in mouse brain endothelial cells, activation of the Wnt/β-catenin signaling pathway, also known as the canonical Wnt pathway, was shown to stabilize endothelial tight junctions (TJs) through transcriptional regulation of the expression of TJ proteins. Because Wnt proteins activate several distinct β-catenin-dependent and independent signaling path...

  2. Wnt3a Promotes the Vasculogenic Mimicry Formation of Colon Cancer via Wnt/β-Catenin Signaling.

    Science.gov (United States)

    Qi, Lisha; Song, Wangzhao; Liu, Zhiyong; Zhao, Xiulan; Cao, Wenfeng; Sun, Baocun

    2015-08-10

    Our previous study provided evidence that non-canonical Wnt signaling is involved in regulating vasculogenic mimicry (VM) formation. However, the functions of canonical Wnt signaling in VM formation have not yet been explored. In this study, we found the presence of VM was related to colon cancer histological differentiation (p colon cancer samples showed increased Wnt3a expression (p colon cancer cells promoted the capacity to form tube-like structures in the three-dimensional (3-D) culture together with increased expression of endothelial phenotype-associated proteins such as VEGFR2 and VE-cadherin. The mouse xenograft model showed that Wnt3a-overexpressing cells grew into larger tumor masses and formed more VM than the control cells. In addition, the Wnt/β-catenin signaling antagonist Dickkopf-1(Dkk1) can reverse the capacity to form tube-like structures and can decrease the expressions of VEGFR2 and VE-cadherin in Wnt3a-overexpressing cells. Taken together, our results suggest that Wnt/β-catenin signaling is involved in VM formation in colon cancer and might contribute to the development of more accurate treatment modalities aimed at VM.

  3. The regulation of osteogenic differentiation by BMP2 and the canonical Wnt signaling pathway and the crosstalk between them%BMP2信号通路与经典 Wnt 信号通路及相互交联对成骨分化的调控

    Institute of Scientific and Technical Information of China (English)

    刘光源; 田发明; 张柳; 刘家寅

    2014-01-01

    The osteogenic differentiation process in mesenchymal stem cells and other lineages that are capable of differentiating into osteoblasts, is regulated by several signal transduction pathways and the dynamic regulatory networks consisted of them.In this process, more and more attention has been paid to the role of BMP2 signaling pathway and canonical Wnt signaling pathway. Previous studies have shown that BMP2 and canonical Wnt signaling pathway can regulate the osteogenic differentiation process in target cells, during which the expression level and functional activity of key molecules in one signaling pathway are regulated by the other.Moreover, they also exhibit cooperative or antagonize interaction on the regulation of osteogenic differentiation biomarkers. This paper briefly summarizes the role of BMP2 and canonical Wnt signaling pathway in regulating osteogenic differentiation and the crosstalk between the two signaling pathways in this process.%在以间充质干细胞为代表的具有成骨分化潜能的细胞中,多条信号传导通路及其构成的动态调控网络参与调控其成骨分化过程。其中BMP2和经典Wnt信号通路在此过程中的作用日益受到关注。国内外研究表明,BMP2和经典Wnt信号通路在调控靶细胞成骨分化过程中伴有彼此通路中的关键分子的表达水平和功能活性的改变,并在一定条件下表现出对成骨分化特异性标志物的协同和拮抗调控。成骨增殖分化过程是一个动态过程,在成骨分化的不同阶段,分子通路的作用不同,相互之间的调节也动态变化的,研究BMP2和经典Wnt信号通路在成骨分化过程中的相互调节作用,对于指导治疗骨质疏松和骨折有重要的作用,本文就BMP2和经典Wnt信号通路对靶细胞成骨分化的调控作用以及在此过程中两条信号通路之间的交联作一简要综述。

  4. Wnt signaling in the regulation of adult hippocampal neurogenesis

    Directory of Open Access Journals (Sweden)

    Lorena eVarela-Nallar

    2013-06-01

    Full Text Available In the adult brain new neurons are continuously generated mainly in two regions, the subventricular zone of the lateral ventricles and the subgranular zone (SGZ in the hippocampal dentate gyrus. In the SGZ, radial neural stem cells give rise to granule cells that integrate into the hippocampal circuitry and are relevant for the plasticity of the hippocampus. Loss of neurogenesis impairs learning and memory, suggesting that this process is important for adult hippocampal function. Adult neurogenesis is tightly regulated by multiple signaling pathways, including the canonical Wnt/beta-catenin pathway. This pathway plays important roles during the development of neuronal circuits and in the adult brain it modulates synaptic transmission and plasticity. Here, we review current knowledge on the regulation of adult hippocampal neurogenesis by the Wnt/beta-catenin signaling cascade and the potential mechanisms involved in this regulation. Also we discuss the evidence supporting that the canonical Wnt pathway is part of the signaling mechanisms involved in the regulation of neurogenesis in different physiological conditions. Finally, some unsolved questions regarding the Wnt-mediated regulation of neurogenesis are discussed.

  5. Wnt signaling in the regulation of adult hippocampal neurogenesis

    Science.gov (United States)

    Varela-Nallar, Lorena; Inestrosa, Nibaldo C.

    2013-01-01

    In the adult brain new neurons are continuously generated mainly in two regions, the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) in the hippocampal dentate gyrus. In the SGZ, radial neural stem cells (NSCs) give rise to granule cells that integrate into the hippocampal circuitry and are relevant for the plasticity of the hippocampus. Loss of neurogenesis impairs learning and memory, suggesting that this process is important for adult hippocampal function. Adult neurogenesis is tightly regulated by multiple signaling pathways, including the canonical Wnt/β-catenin pathway. This pathway plays important roles during the development of neuronal circuits and in the adult brain it modulates synaptic transmission and plasticity. Here, we review current knowledge on the regulation of adult hippocampal neurogenesis by the Wnt/β-catenin signaling cascade and the potential mechanisms involved in this regulation. Also we discuss the evidence supporting that the canonical Wnt pathway is part of the signaling mechanisms involved in the regulation of neurogenesis in different physiological conditions. Finally, some unsolved questions regarding the Wnt-mediated regulation of neurogenesis are discussed. PMID:23805076

  6. Effects of Wnt signaling on brown adipocyte differentiation and metabolism mediated by PGC-1alpha

    DEFF Research Database (Denmark)

    Kang, Sona; Bajnok, Laszlo; Longo, Kenneth A;

    2005-01-01

    expression of PGC-1alpha is required for activation of uncoupling protein 1 (UCP1). Wnt10b blocks brown adipose tissue development and expression of UCP1 when expressed from the fatty acid binding protein 4 promoter, even when mice are administered a beta3-agonist. In differentiated brown adipocytes......Activation of canonical Wnt signaling inhibits brown adipogenesis of cultured cells by impeding induction of PPARgamma and C/EBPalpha. Although enforced expression of these adipogenic transcription factors restores lipid accumulation and expression of FABP4 in Wnt-expressing cells, additional......, activation of Wnt signaling suppresses expression of UCP1 through repression of PGC-1alpha. Consistent with these in vitro observations, UCP1-Wnt10b transgenic mice, which express Wnt10b in interscapular tissue, lack functional brown adipose tissue. While interscapular tissue of UCP1-Wnt10b mice lacks...

  7. Wnt signalling pathway parameters for mammalian cells.

    Directory of Open Access Journals (Sweden)

    Chin Wee Tan

    Full Text Available Wnt/β-catenin signalling regulates cell fate, survival, proliferation and differentiation at many stages of mammalian development and pathology. Mutations of two key proteins in the pathway, APC and β-catenin, have been implicated in a range of cancers, including colorectal cancer. Activation of Wnt signalling has been associated with the stabilization and nuclear accumulation of β-catenin and consequential up-regulation of β-catenin/TCF gene transcription. In 2003, Lee et al. constructed a computational model of Wnt signalling supported by experimental data from analysis of time-dependent concentration of Wnt signalling proteins in Xenopus egg extracts. Subsequent studies have used the Xenopus quantitative data to infer Wnt pathway dynamics in other systems. As a basis for understanding Wnt signalling in mammalian cells, a confocal live cell imaging measurement technique is developed to measure the cell and nuclear volumes of MDCK, HEK293T cells and 3 human colorectal cancer cell lines and the concentrations of Wnt signalling proteins β-catenin, Axin, APC, GSK3β and E-cadherin. These parameters provide the basis for formulating Wnt signalling models for kidney/intestinal epithelial mammalian cells. There are significant differences in concentrations of key proteins between Xenopus extracts and mammalian whole cell lysates. Higher concentrations of Axin and lower concentrations of APC are present in mammalian cells. Axin concentrations are greater than APC in kidney epithelial cells, whereas in intestinal epithelial cells the APC concentration is higher than Axin. Computational simulations based on Lee's model, with this new data, suggest a need for a recalibration of the model.A quantitative understanding of Wnt signalling in mammalian cells, in particular human colorectal cancers requires a detailed understanding of the concentrations of key protein complexes over time. Simulations of Wnt signalling in mammalian cells can be initiated

  8. Gene expression analysis of canonical Wnt pathway transcriptional regulators during early morphogenesis of the facial region in the mouse embryo.

    Science.gov (United States)

    Vendrell, Victor; Summerhurst, Kristen; Sharpe, James; Davidson, Duncan; Murphy, Paula

    2009-06-01

    Structures and features of the face, throat and neck are formed from a series of branchial arches that grow out along the ventrolateral aspect of the embryonic head. Multiple signalling pathways have been implicated in patterning interactions that lead to species-specific growth and differentiation within the branchial region that sculpt these features. A direct role for Wnt signalling in particular has been shown. The spatial and temporal distribution of Wnt pathway components contributes to the operation of the signalling system. We present the precise distribution of gene expression of canonical Wnt pathway transcriptional regulators, Tcf1, Lef1, Tcf3, Tcf4 and beta-catenin between embryonic day (E) 9.5 and 11.5. In situ hybridization combined with Optical Projection Tomography was used to record and compare distribution of transcripts in 3D within the developing branchial arches. This shows widespread yet very specific expression of the gene set indicating that all genes contribute to proper patterning of the region. Tcf1 and Lef1 are more prominent in rostral arches, particularly at later ages, and Tcf3 and Tcf4 are in general expressed more deeply (medial/endodermal aspect) in the arches than Tcf1 and Lef1. Comparison with Wnt canonical pathway readout patterns shows that the relationship between the expression of individual transcription factors and activation of the pathway is not simple, indicating complexity and flexibility in the signalling system.

  9. Canonical and alternative MAPK signaling.

    Science.gov (United States)

    Pimienta, Genaro; Pascual, Jaime

    2007-11-01

    The archetype of MAPK cascade activation is somewhat challenged by the most recent discovery of unexpected phosphorylation patterns, alternative activation mechanisms and sub-cellular localization, in various members of this protein kinase family. In particular, activation by autophosphorylation pathways has now been described for the three best understood MAPK subgroups: ERK1/2; JNK1/2 and p38 alpha/beta. Also, a form of dosage compensation between homologs has been shown to occur in the case of ERK1/2 and JNK1/2. In this paper we summarize the MAPK activation pathway, with an emphasis on non-canonical examples. We use this information to propose a model for MAPK signal transduction that considers a cross-talk between MAPKs with different activation loop sequence motifs and unique C-terminal extensions. We highlight the occurrence of non-canonical substrate specificity during MAPK auto-activation, in strong connection with MAPK homo- and hetero-dimerization events.

  10. Promising Druggable Target in Head and Neck Squamous Cell Carcinoma: Wnt Signaling

    Directory of Open Access Journals (Sweden)

    Amnani Aminuddin

    2016-08-01

    Full Text Available Canonical Wnt signaling pathway, also known as Wnt/β-catenin signaling pathway, is a crucial mechanism for cellular maintenance and development. It regulates cell cycle progression, apoptosis, proliferation, migration and differentiation. Dysregulation of this pathway correlates with oncogenesis in various tissues including breast, colon, pancreatic as well as head and neck cancers. Furthermore, the canonical Wnt signaling pathway has also been described as one of the critical signaling pathways for regulation of normal stem cells as well as cancer cells with stem cell-like features, termed cancer stem cells. In this review, we will briefly describe the basic mechanisms of Wnt signaling pathway and its crucial roles in normal regulation of cellular processes as well as in the development of cancer. Next, we will highlight the roles of canonical Wnt signaling pathway in the regulation of cancer stem cell properties namely self-renewal, differentiation, metastasis and drug resistance abilities, particularly in head and neck squamous cell carcinoma. Finally, we will examine the findings of several recent studies which explore druggable targets in the canonical Wnt signaling pathway which could be valuable to improve the treatment outcome for head and neck cancer.

  11. The Wnt signaling pathway in cancer.

    Science.gov (United States)

    Duchartre, Yann; Kim, Yong-Mi; Kahn, Michael

    2016-03-01

    The Wnt signaling pathway is critically involved in both the development and homeostasis of tissues via regulation of their endogenous stem cells. Aberrant Wnt signaling has been described as a key player in the initiation of and/or maintenance and development of many cancers, via affecting the behavior of Cancer Stem Cells (CSCs). CSCs are considered by most to be responsible for establishment of the tumor and also for disease relapse, as they possess inherent drug-resistance properties. The development of new therapeutic compounds targeting the Wnt signaling pathway promises new hope to eliminate CSCs and achieve cancer eradication. However, a major challenge resides in developing a strategy efficient enough to target the dysregulated Wnt pathway in CSCs, while being safe enough to not damage the normal somatic stem cell population required for tissue homeostasis and repair. Here we review recent therapeutic approaches to target the Wnt pathway and their clinical applications.

  12. Wnt signaling in the niche enforces hematopoietic stem cell quiescence and is necessary to preserve self-renewal in vivo.

    Science.gov (United States)

    Fleming, Heather E; Janzen, Viktor; Lo Celso, Cristina; Guo, Jun; Leahy, Kathleen M; Kronenberg, Henry M; Scadden, David T

    2008-03-06

    Wingless (Wnt) is a potent morphogen demonstrated in multiple cell lineages to promote the expansion and maintenance of stem and progenitor cell populations. Wnt effects are highly context dependent, and varying effects of Wnt signaling on hematopoietic stem cells (HSCs) have been reported. We explored the impact of Wnt signaling in vivo, specifically in the context of the HSC niche by using an osteoblast-specific promoter driving expression of the paninhibitor of canonical Wnt signaling, Dickkopf1 (Dkk1). Here we report that Wnt signaling was markedly inhibited in HSCs and, unexpectedly given prior reports, reduction in HSC Wnt signaling resulted in reduced p21Cip1 expression, increased cell cycling, and a progressive decline in regenerative function after transplantation. This effect was microenvironment determined, but irreversible if the cells were transferred to a normal host. Wnt pathway activation in the niche is required to limit HSC proliferation and preserve the reconstituting function of endogenous hematopoietic stem cells.

  13. Expression profiling and functional analysis of wnt signaling mechanisms in mesenchymal stem cells.

    Science.gov (United States)

    Etheridge, S Leah; Spencer, Gary J; Heath, Deborah J; Genever, Paul G

    2004-01-01

    Through their broad differentiation potential, mesenchymal stem cells (MSCs) are candidates for a range of therapeutic applications, but the precise signaling pathways that determine their differentiated fate are not fully understood. Evidence is emerging that developmental signaling cues may be important in regulating stem cell self-renewal and differentiation programs. Here we have identified a consistent expression profile of Wnt signaling molecules in MSCs and provide evidence that an endogenous canonical Wnt pathway functions in these cells. Wnts bind to Frizzled (Fz) receptors and subsequent canonical signaling inhibits glycogen synthase kinase-3beta (GSK-3beta), causing beta-catenin translocation into the nucleus to induce target gene expression. In human MSCs isolated from bone marrow of different donors, we appear to have identified a common Wnt/Fz expression profile using reverse transcriptase polymerase chain reaction (RT-PCR). Associated Wnt signaling components, including low-density lipoprotein receptor-related protein-5 (LRP-5), kremen-1, dickkopf-1 (Dkk-1), secreted Frizzled-related peptide (sFRP)-2, sFRP3, sFRP4, Disheveled (Dvl), GSK-3beta, adenomatous polyposis coli (APC), beta-catenin,T-cell factor (TCF)-1, and TCF-4, were also identified. Nuclear beta-catenin was observed in 30%-40% of MSCs, indicative of endogenous Wnt signaling. Exposure to both Wnt3a and Li+ ions, which promotes canonical Wnt signaling by inhibiting GSK-3beta, reduced phosphorylation of beta-catenin in MSCs and increased beta-catenin nuclear translocation approximately threefold over that of the controls. Our findings indicate that autocrine Wnt signaling operates in primitive MSC populations and supports previous evidence that Wnt signaling regulates mesenchymal lineage specification. The identification of a putative common Wnt/Fz molecular signature in MSCs will contribute to our understanding of the molecular mechanisms that regulate self-renewal and lineage

  14. Wnt signaling inhibits CTL memory programming.

    Science.gov (United States)

    Xiao, Zhengguo; Sun, Zhifeng; Smyth, Kendra; Li, Lei

    2013-12-01

    Induction of functional CTLs is one of the major goals for vaccine development and cancer therapy. Inflammatory cytokines are critical for memory CTL generation. Wnt signaling is important for CTL priming and memory formation, but its role in cytokine-driven memory CTL programming is unclear. We found that wnt signaling inhibited IL-12-driven CTL activation and memory programming. This impaired memory CTL programming was attributed to up-regulation of eomes and down-regulation of T-bet. Wnt signaling suppressed the mTOR pathway during CTL activation, which was different to its effects on other cell types. Interestingly, the impaired memory CTL programming by wnt was partially rescued by mTOR inhibitor rapamycin. In conclusion, we found that crosstalk between wnt and the IL-12 signaling inhibits T-bet and mTOR pathways and impairs memory programming which can be recovered in part by rapamycin. In addition, direct inhibition of wnt signaling during CTL activation does not affect CTL memory programming. Therefore, wnt signaling may serve as a new tool for CTL manipulation in autoimmune diseases and immune therapy for certain cancers.

  15. Wnt signaling and stem cell control

    Institute of Scientific and Technical Information of China (English)

    Roel Nusse

    2008-01-01

    Wnt signaling has been implicated in the control over various types of stem cells and may act as a niche factor to maintain stem cells in a self-renewing state.As currently understood,Wnt proteins bind to receptors of the Frizzled and LRP families on the cell surface.Through several cytoplasmic relay components,the signal is transduced to B-catenin,which then enters the nucleus and forms a complex with TCF to activate transcription of Wnt target genes.Wnts can also signal through tyrosine kinase receptors,in particular the ROR and RYK receptors,leading to alternative modes of Wnt signaling.During the growth of tissues,these ligands and receptors are dynamically expressed,often transcriptionally controlled by Wnt signals themselves,to ensure the right balance between proliferation and differentiation.Isolated Wnt proteins are active on a variety of stem cells,including neural,mammary and embryonic stem cells.In general,Wnt proteins act to maintain the undifferentiated state of stem cells,while other growth factors instruct the cells to proliferate.These other factors include FGF and EGF,signaling through tyrosine kinase pathways.

  16. Involvement of wnt signaling pathways in the metamorphosis of the bryozoan bugula neritina

    KAUST Repository

    Wong, Yue Him

    2012-03-20

    In this study, we analyzed the metamorphosis of the marine bryozoan Bugula neritina. We observed the morphogenesis of the ancestrula. We defined three distinct pre-ancestrula stages based on the anatomy of the developing polypide and the overall morphology of pre-ancestrula. We then used an annotation based enrichment analysis tool to analyze the B. neritina transcriptome and identified over-representation of genes related to Wnt signaling pathways, suggesting its involvement in metamorphosis. Finally, we studied the temporal-spatial gene expression studies of several Wnt pathway genes. We found that one of the Wnt ligand, BnWnt10, was expressed spatially opposite to the Wnt antagonist BnsFRP within the blastemas, which is the presumptive polypide. Down-stream components of the canonical Wnt signaling pathway were exclusively expressed in the blastemas. Bn?catenin and BnFz5/8 were exclusively expressed in the blastemas throughout the metamorphosis. Based on the genes expression patterns, we propose that BnWnt10 and BnsFRP may relate to the patterning of the polypide, in which the two genes served as positional signals and contributed to the polarization of the blastemas. Another Wnt ligand, BnWnt6, was expressed in the apical part of the pre-ancestrula epidermis. Overall, our findings suggest that the Wnt signaling pathway may be important to the pattern formation of polypide and the development of epidermis. © 2012 Wong et al.

  17. KLF4 transcriptionally activates non-canonical WNT5A to control epithelial stratification.

    Science.gov (United States)

    Tetreault, Marie-Pier; Weinblatt, Daniel; Shaverdashvili, Khvaramze; Yang, Yizeng; Katz, Jonathan P

    2016-05-17

    Epithelial differentiation and stratification are essential for normal homeostasis, and disruption of these processes leads to both injury and cancer. The zinc-finger transciption factor KLF4 is a key driver of epithelial differentiation, yet the mechanisms and targets by which KLF4 controls differentiation are not well understood. Here, we define WNT5A, a non-canonical Wnt ligand implicated in epithelial differentiation, repair, and cancer, as a direct transcriptional target that is activated by KLF4 in squamous epithelial cells. Further, we demonstrate functionally that WNT5A mediates KLF4 control of epithelial differentiation and stratification, as treatment of keratinocytes with WNT5A rescues defective epithelial stratification resulting from KLF4 loss. Finally, we show that the small GTPase CDC42 is regulated by KLF4 in a WNT5A dependent manner. As such, we delineate a novel pathway for epithelial differentiation and stratification and define potential therapeutic targets for epithelial diseases.

  18. The Meckel-Gruber syndrome protein TMEM67 controls basal body positioning and epithelial branching morphogenesis in mice via the non-canonical Wnt pathway

    Directory of Open Access Journals (Sweden)

    Zakia A. Abdelhamed

    2015-06-01

    Full Text Available Ciliopathies are a group of developmental disorders that manifest with multi-organ anomalies. Mutations in TMEM67 (MKS3 cause a range of human ciliopathies, including Meckel-Gruber and Joubert syndromes. In this study we describe multi-organ developmental abnormalities in the Tmem67tm1Dgen/H1 knockout mouse that closely resemble those seen in Wnt5a and Ror2 knockout mice. These include pulmonary hypoplasia, ventricular septal defects, shortening of the body longitudinal axis, limb abnormalities, and cochlear hair cell stereociliary bundle orientation and basal body/kinocilium positioning defects. The basal body/kinocilium complex was often uncoupled from the hair bundle, suggesting aberrant basal body migration, although planar cell polarity and apical planar asymmetry in the organ of Corti were normal. TMEM67 (meckelin is essential for phosphorylation of the non-canonical Wnt receptor ROR2 (receptor-tyrosine-kinase-like orphan receptor 2 upon stimulation with Wnt5a-conditioned medium. ROR2 also colocalises and interacts with TMEM67 at the ciliary transition zone. Additionally, the extracellular N-terminal domain of TMEM67 preferentially binds to Wnt5a in an in vitro binding assay. Cultured lungs of Tmem67 mutant mice failed to respond to stimulation of epithelial branching morphogenesis by Wnt5a. Wnt5a also inhibited both the Shh and canonical Wnt/β-catenin signalling pathways in wild-type embryonic lung. Pulmonary hypoplasia phenotypes, including loss of correct epithelial branching morphogenesis and cell polarity, were rescued by stimulating the non-canonical Wnt pathway downstream of the Wnt5a-TMEM67-ROR2 axis by activating RhoA. We propose that TMEM67 is a receptor that has a main role in non-canonical Wnt signalling, mediated by Wnt5a and ROR2, and normally represses Shh signalling. Downstream therapeutic targeting of the Wnt5a-TMEM67-ROR2 axis might, therefore, reduce or prevent pulmonary hypoplasia in ciliopathies and other congenital

  19. PTH1–34 Blocks Radiation-induced Osteoblast Apoptosis by Enhancing DNA Repair through Canonical Wnt Pathway*

    Science.gov (United States)

    Chandra, Abhishek; Lin, Tiao; Zhu, Ji; Tong, Wei; Huo, Yanying; Jia, Haoruo; Zhang, Yejia; Liu, X. Sherry; Cengel, Keith; Xia, Bing; Qin, Ling

    2015-01-01

    Focal radiotherapy for cancer patients has detrimental effects on bones within the radiation field and the primary clinical signs of bone damage include the loss of functional osteoblasts. We reported previously that daily injection of parathyroid hormone (PTH, 1–34) alleviates radiation-induced osteopenia in a preclinical radiotherapy model by improving osteoblast survival. To elucidate the molecular mechanisms, we irradiated osteoblastic UMR 106-01 cells and calvarial organ culture and demonstrated an anti-apoptosis effect of PTH1–34 on these cultures. Inhibitor assay indicated that PTH exerts its radioprotective action mainly through protein kinase A/β-catenin pathway. γ-H2AX foci staining and comet assay revealed that PTH efficiently promotes the repair of DNA double strand breaks (DSBs) in irradiated osteoblasts via activating the β-catenin pathway. Interestingly, Wnt3a alone also blocked cell death and accelerated DNA repair in primary osteoprogenitors, osteoblastic and osteocytic cells after radiation through the canonical signaling. Further investigations revealed that both Wnt3a and PTH increase the amount of Ku70, a core protein for initiating the assembly of DSB repair machinery, in osteoblasts after radiation. Moreover, down-regulation of Ku70 by siRNA abrogated the prosurvival effect of PTH and Wnt3a on irradiated osteoblasts. In summary, our results identify a novel role of PTH and canonical Wnt signaling in regulating DSB repair machinery and apoptosis in osteoblasts and shed light on using PTH1–34 or Wnt agonist as possible therapy for radiation-induced osteoporosis. PMID:25336648

  20. Activation of the canonical Wnt pathway leads to loss of hematopoietic stem cell repopulation and multilineage differentiation block

    DEFF Research Database (Denmark)

    Kirstetter, Peggy; Anderson, Kristina; Porse, Bo T;

    2006-01-01

    of hematopoietic stem cell function was associated with decreased expression of Cdkn1a (encoding the cell cycle inhibitor p21(cdk)), Sfpi1, Hoxb4 and Bmi1 (encoding the transcription factors PU.1, HoxB4 and Bmi-1, respectively) and altered integrin expression in Lin(-)Sca-1(+)c-Kit(+) cells, whereas PU.1......Wnt signaling increases hematopoietic stem cell self-renewal and is activated in both myeloid and lymphoid malignancies, indicating involvement in both normal and malignant hematopoiesis. We report here activated canonical Wnt signaling in the hematopoietic system through conditional expression...... of a stable form of beta-catenin. This enforced expression led to hematopoietic failure associated with loss of myeloid lineage commitment at the granulocyte-macrophage progenitor stage; blocked erythrocyte differentiation; disruption of lymphoid development; and loss of repopulating stem cell activity. Loss...

  1. Wnt signaling in liver physiology and pathology

    Institute of Scientific and Technical Information of China (English)

    Satdarshan P. Singh Monga

    2009-01-01

    @@ 1 Wnt/β-catenin signaling This signaling pathway is known to play key roles during development and in maintaining homeostasis in many adult tissues. Its aberrant activation is associated with cancers in many tissues such as breast, colon, pancreas, skin and liver.

  2. Wnt Signaling in Cell Motility and Invasion: Drawing Parallels between Development and Cancer

    Directory of Open Access Journals (Sweden)

    Alanna E. Sedgwick

    2016-08-01

    Full Text Available The importance of canonical and non-canonical Wnt signal transduction cascades in embryonic development and tissue homeostasis is well recognized. The aberrant activation of these pathways in the adult leads to abnormal cellular behaviors, and tumor progression is frequently a consequence. Here we discuss recent findings and analogies between Wnt signaling in developmental processes and tumor progression, with a particular focus on cell motility and matrix invasion and highlight the roles of the ARF (ADP-Ribosylation Factor and Rho-family small GTP-binding proteins. Wnt-regulated signal transduction from cell surface receptors, signaling endosomes and/or extracellular vesicles has the potential to profoundly influence cell movement, matrix degradation and paracrine signaling in both development and disease.

  3. Regulative effect of the canonical Wnt pathway on osteogenesis%经典Wnt信号通路对细胞成骨分化的调控作用

    Institute of Scientific and Technical Information of China (English)

    邱绮虹; 梁敏

    2014-01-01

    The Wnt signaling pathway,including the canonical and the non-canonical,is a conservative pathway which participates in organ development and tissue metabolism.The canonical Wnt pathway plays an important role in osteogenesis,bone formation and mineralization through the osteogenesis associated transcription factors.The canonical Wnt pathway also regulates osteogenic differentiation of the stem cells in the periodontal tissue and the regulative effect is influenced by the microenvironment.Understanding of the canonical Wnt pathway will contribute to the treatment of some related bone diseases.%Wnt信号通路是参与体内多种器官发育和组织新陈代谢的保守性通路,可分为经典和非经典Wnt信号通路.其中,经典Wnt信号通路通过调节下游的成骨相关转录因子调控细胞成骨分化、骨基质形成和矿化,且在细胞分化的不同阶段发挥不同的调控作用.此外,经典Wnt信号通路还调控牙周组织干细胞成骨分化,该作用受外界微环境的影响.加深对经典Wnt信号通路的认识有助于治疗相关的骨疾病.

  4. Spatial and temporal aspects of Wnt signaling and planar cell polarity during vertebrate embryonic development.

    Science.gov (United States)

    Sokol, Sergei Y

    2015-06-01

    Wnt signaling pathways act at multiple locations and developmental stages to specify cell fate and polarity in vertebrate embryos. A long-standing question is how the same molecular machinery can be reused to produce different outcomes. The canonical Wnt/β-catenin branch modulates target gene transcription to specify cell fates along the dorsoventral and anteroposterior embryonic axes. By contrast, the Wnt/planar cell polarity (PCP) branch is responsible for cell polarization along main body axes, which coordinates morphogenetic cell behaviors during gastrulation and neurulation. Whereas both cell fate and cell polarity are modulated by spatially- and temporally-restricted Wnt activity, the downstream signaling mechanisms are very diverse. This review highlights recent progress in the understanding of Wnt-dependent molecular events leading to the establishment of PCP and linking it to early morphogenetic processes.

  5. How the Wnt signaling pathway protects from neurodegeneration: the mitochondrial scenario

    Science.gov (United States)

    Arrázola, Macarena S.; Silva-Alvarez, Carmen; Inestrosa, Nibaldo C.

    2015-01-01

    Alzheimer’s disease (AD) is the most common neurodegenerative disorder and is characterized by progressive memory loss and cognitive decline. One of the hallmarks of AD is the overproduction of amyloid-beta aggregates that range from the toxic soluble oligomer (Aβo) form to extracellular accumulations in the brain. Growing evidence indicates that mitochondrial dysfunction is a common feature of neurodegenerative diseases and is observed at an early stage in the pathogenesis of AD. Reports indicate that mitochondrial structure and function are affected by Aβo and can trigger neuronal cell death. Mitochondria are highly dynamic organelles, and the balance between their fusion and fission processes is essential for neuronal function. Interestingly, in AD, the process known as “mitochondrial dynamics” is also impaired by Aβo. On the other hand, the activation of the Wnt signaling pathway has an essential role in synaptic maintenance and neuronal functions, and its deregulation has also been implicated in AD. We have demonstrated that canonical Wnt signaling, through the Wnt3a ligand, prevents the permeabilization of mitochondrial membranes through the inhibition of the mitochondrial permeability transition pore (mPTP), induced by Aβo. In addition, we showed that non-canonical Wnt signaling, through the Wnt5a ligand, protects mitochondria from fission-fusion alterations in AD. These results suggest new approaches by which different Wnt signaling pathways protect neurons in AD, and support the idea that mitochondria have become potential therapeutic targets for the treatment of neurodegenerative disorders. Here we discuss the neuroprotective role of the canonical and non-canonical Wnt signaling pathways in AD and their differential modulation of mitochondrial processes, associated with mitochondrial dysfunction and neurodegeneration. PMID:25999816

  6. Wnt signaling in development and disease

    Directory of Open Access Journals (Sweden)

    Yang Yingzi

    2012-04-01

    Full Text Available Abstract Cell signaling mediated by morphogens is essential to coordinate growth and patterning, two key processes that govern the formation of a complex multi-cellular organism. During growth and patterning, cells are specified by both quantitative and directional information. While quantitative information regulates cell proliferation and differentiation, directional information is conveyed in the form of cell polarities instructed by local and global cues. Major morphogens like Wnts play critical roles in embryonic development and they are also important in maintaining tissue homeostasis. Abnormal regulation of these signaling events leads to a diverse array of devastating diseases including cancer. Wnts transduce their signals through several distinct pathways and they regulate vertebrate embryonic development by providing both quantitative and directional information. Here, taking the developing skeletal system as an example, we review our work on Wnt signaling pathways in various aspects of development. We focus particularly on our most recent findings that showed that in vertebrates, Wnt5a acts as a global cue to establishing planar cell polarity (PCP. Our work suggests that Wnt morphogens regulate development by integrating quantitative and directional information. Our work also provides important insights in disease like Robinow syndrome, brachydactyly type B1 (BDB1 and spina bifida, which can be caused by human mutations in the Wnt/PCP signaling pathway.

  7. Wnt-β-Catenin Signaling Promotes the Maturation of Mast Cells

    Directory of Open Access Journals (Sweden)

    Tomoko Yamaguchi

    2016-01-01

    Full Text Available Mast cells play an important role in the pathogenesis of allergic diseases. Immature mast cells migrate into peripheral tissues from the bone marrow and undergo complete maturation. Interestingly, mast cells have characteristics similar to hematopoietic stem cells (HSCs, such as self-renewal and c-kit expression. In HSCs, Wnt signaling is involved in their maintenance and differentiation. On the other hand, the relation between Wnt signaling and mast cell differentiation is poorly understood. To study whether Wnt signals play a role in the maturation of mast cells, we studied the effect of Wnt proteins on mast cell maturation of bone marrow-derived mast cells (BMMCs. The expression levels of CD81 protein and histidine decarboxylase mRNA and activity of mast cell-specific protease were all elevated in BMMCs treated with Wnt5a. In addition, Wnt5a induced the expression of Axin2 and TCF mRNA in BMMCs. These results showed that Wnt5a could promote the maturation of mast cells via the canonical Wnt signaling pathway and provide important insights into the molecular mechanisms underlying the differentiation of mast cells.

  8. Moringin activates Wnt canonical pathway by inhibiting GSK3β in a mouse model of experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Giacoppo, Sabrina; Soundara Rajan, Thangavelu; De Nicola, Gina Rosalinda; Iori, Renato; Bramanti, Placido; Mazzon, Emanuela

    2016-01-01

    Aberrant canonical Wnt-β-catenin signaling has been reported in multiple sclerosis (MS), although the results are controversial. The present study aimed to examine the role of the Wnt-β-catenin pathway in experimental MS and also to test moringin (4-[α-L-rhamnopyranosyloxy]-benzyl isothiocyanate), resulting from exogenous myrosinase hydrolysis of the natural phytochemical glucomoringin 4(α-L-rhamnosyloxy)-benzyl glucosinolate as a modulator of neuroinflammation via the β-catenin-PPARγ axis. Experimental autoimmune encephalomyelitis (EAE), the most common model of MS, was induced in C57BL/6 mice by immunization with MOG35-55. Released moringin (10 mg/kg glucomoringin +5 μL myrosinase/mouse) was administered daily for 1 week before EAE induction and continued until mice were killed on day 28 after EAE induction. Our results clearly showed that the Wnt-β-catenin pathway was downregulated in the EAE model, whereas moringin pretreatment was able to avert this. Moringin pretreatment normalizes the aberrant Wnt-β-catenin pathway, resulting in GSK3β inhibition and β-catenin upregulation, which regulates T-cell activation (CD4 and FoxP3), suppresses the main inflammatory mediators (IL-1β, IL-6, and COX2), through activation of PPARγ. In addition, moringin attenuates apoptosis by reducing the expression of the Fas ligand and cleaved caspase 9, and in parallel increases antioxidant Nrf2 expression in EAE mice. Taken together, our results provide an interesting discovery in identifying moringin as a modulator of the Wnt-β-catenin signaling cascade and as a new potential therapeutic target for MS treatment.

  9. Wnt signaling interacts with Shh to regulate taste papilla development.

    Science.gov (United States)

    Iwatsuki, Ken; Liu, Hong-Xiang; Grónder, Albert; Singer, Meredith A; Lane, Timothy F; Grosschedl, Rudolf; Mistretta, Charlotte M; Margolskee, Robert F

    2007-02-13

    Wnt and Shh signaling pathways are critical for the development and maturation of many epithelial tissues. Both pathways have roles in stem cell maintenance, tissue development, and tumorigenesis. However, linkage between these pathways in mammalian systems had not been well established. Here, we report that Shh expression in fungiform papillae and formation of normal mature fungiform papillae depend on signaling through Wnt and beta-catenin. We observed that during fungiform papilla formation in mice, Shh and components of the Wnt/beta-catenin signaling pathway are expressed together in the developing placode. The elimination of Wnt/beta-catenin signaling in either Lef1 or Wnt10b knockout mice resulted in down-regulation of Shh expression. In addition, the size and number of fungiform papillae were greatly reduced in Lef1 knockout mice. By examining embryonic mouse tongues in culture we determined that activation of Wnt/beta-catenin signaling up-regulates Shh expression. We observed that blocking Shh signaling in cultured tongue explants enhanced papillae formation and was accompanied by an up-regulation of Wnt/beta-catenin signaling, indicating that Shh inhibits the Wnt/beta-catenin pathway. Exogenously added Shh suppressed expression of endogenous Shh and inhibited Wnt/beta-catenin signaling (assessed in TOPGAL mice), further implicating Shh as an inhibitor of the Wnt/beta-catenin pathway. Our observations indicate that Wnt/beta-catenin signaling and interactions between the Wnt and Shh pathways play essential roles in the development of fungiform papillae.

  10. Negative feedback regulation of Wnt signaling via N-linked fucosylation in zebrafish.

    Science.gov (United States)

    Feng, Lei; Jiang, Hao; Wu, Peng; Marlow, Florence L

    2014-11-15

    L-fucose, a monosaccharide widely distributed in eukaryotes and certain bacteria, is a determinant of many functional glycans that play central roles in numerous biological processes. The molecular mechanism, however, by which fucosylation mediates these processes remains largely elusive. To study how changes in fucosylation impact embryonic development, we up-regulated N-linked fucosylation via over-expression of a key GDP-Fucose transporter, Slc35c1, in zebrafish. We show that Slc35c1 overexpression causes elevated N-linked fucosylation and disrupts embryonic patterning in a transporter activity dependent manner. We demonstrate that patterning defects associated with enhanced N-linked fucosylation are due to diminished canonical Wnt signaling. Chimeric analyses demonstrate that elevated Slc35c1 expression in receiving cells decreases the signaling range of Wnt8a during zebrafish embryogenesis. Moreover, we provide biochemical evidence that this decrease is associated with reduced Wnt8 ligand and elevated Lrp6 coreceptor, which we show are both substrates for N-linked fucosylation in zebrafish embryos. Strikingly, slc35c1 expression is regulated by canonical Wnt signaling. These results suggest that Wnt limits its own signaling activity in part via up-regulation of a transporter, slc35c1 that promotes terminal fucosylation and thereby limits Wnt activity.

  11. Heterotrimeric Go protein links Wnt-Frizzled signaling with ankyrins to regulate the neuronal microtubule cytoskeleton.

    NARCIS (Netherlands)

    Luchtenborg, A.M.; Solis, G.P.; Egger-Adam, D.; Koval, A.; Lin, C.; Blanchard, M.G.; Kellenberger, S.; Katanaev, V.L.

    2014-01-01

    Drosophila neuromuscular junctions (NMJs) represent a powerful model system with which to study glutamatergic synapse formation and remodeling. Several proteins have been implicated in these processes, including components of canonical Wingless (Drosophila Wnt1) signaling and the giant isoforms of t

  12. Piroxicam and c-phycocyanin prevent colon carcinogenesis by inhibition of membrane fluidity and canonical Wnt/β-catenin signaling while up-regulating ligand dependent transcription factor PPARγ.

    Science.gov (United States)

    Saini, Manpreet Kaur; Sanyal, Sankar Nath

    2014-06-01

    The colon cancer tissues from DMH treated rats exhibited higher membrane potential, fluidity and changed lipid order as examined by Merocyanine 540 and 1,6-diphenyl-1,3,5-hexatriene, respectively. A transition from gel to liquid crystalline state was observed by Laurdan fluorescence and also reduced fluorescence quenching of NBD-PE as contributed in the decreased membrane lipid phase separation. With piroxicam, a traditional NSAID and c-phycocyanin, a biliprotein from Spirulina platensis, these effects were normalized. An augmented intracellular Ca(+2) had contributed to the drug mediated apoptosis which is supported by an elevated calpain-9 expression. Histopathologically, a large pool of secreted acid/neutral mucopolysaccrides as well as the presence of blood vessels and dysplastic crypts signifies invasive mucinous adenocarcinoma while both the drugs reduced these neoplastic alterations. Wnt/β-catenin pathway was also found to be up-regulated which served as a crucial indicator for cancer cell growth. A concomitant down regulation of PPARγ was noted in DMH treatment which is associated with tumor progression. The expression of PPARα and δ, the other two isoforms of PPAR family was also modulated. We conclude that piroxicam and c-phycocyanin exert their anti-neoplastic effects via regulating membrane properties, raising calpain-9 and PPARγ expression while suppressing Wnt/β-catenin signaling in experimental colon carcinogenesis.

  13. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Go J., E-mail: medical21go@yahoo.co.jp; Saya, Hideyuki

    2014-01-10

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup high}/ c-Myc {sup low} and proliferative cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup low}/ c-Myc {sup high}.

  14. A Novel Role for Matrix Metalloproteinases In Regulating Mammary Stem Cell Function via the Wnt Signaling Pathway

    Science.gov (United States)

    Kessenbrock, Kai; Dijkgraaf, Gerrit J. P.; Lawson, Devon A.; Littlepage, Laurie E.; Shahi, Payam; Pieper, Ursula; Werb, Zena

    2013-01-01

    SUMMARY The microenvironment provides cues that control the behavior of epithelial stem and progenitor cells. Here, we identify matrix metalloproteinase-3 (MMP3) as a novel regulator of Wnt signaling and mammary stem cell (MaSC) activity. We show that MMP3 overexpression promotes hyperplastic epithelial growth, surprisingly, in a non-proteolytic manner via its hemopexin (HPX) domain. We demonstrate that MMP3-HPX specifically binds and inactivates Wnt5b, a non-canonical Wnt ligand that inhibits canonical Wnt signaling and mammary epithelial outgrowth in vivo. Indeed, transplants overexpressing MMP3 display increased canonical Wnt signaling, demonstrating that MMP3 is an extracellular regulator of the Wnt signaling pathway. MMP3-deficient mice exhibit decreased MaSC populations and diminished mammary reconstituting activity, while MMP3 overexpression elevates MaSC function indicating that MMP3 is necessary for the maintenance of MaSCs. Our study reveals a novel mechanism by a microenvironmental protease that regulates Wnt signaling and impacts adult epithelial stem cell function. PMID:23871604

  15. MITF drives endolysosomal biogenesis and potentiates Wnt signaling in melanoma cells

    Science.gov (United States)

    Ploper, Diego; Taelman, Vincent F.; Robert, Lidia; Perez, Brian S.; Titz, Björn; Chen, Hsiao-Wang; Graeber, Thomas G.; von Euw, Erika; Ribas, Antoni; De Robertis, Edward M.

    2015-01-01

    Canonical Wnt signaling plays an important role in development and disease, regulating transcription of target genes and stabilizing many proteins phosphorylated by glycogen synthase kinase 3 (GSK3). We observed that the MiT family of transcription factors, which includes the melanoma oncogene MITF (micropthalmia-associated transcription factor) and the lysosomal master regulator TFEB, had the highest phylogenetic conservation of three consecutive putative GSK3 phosphorylation sites in animal proteomes. This finding prompted us to examine the relationship between MITF, endolysosomal biogenesis, and Wnt signaling. Here we report that MITF expression levels correlated with the expression of a large subset of lysosomal genes in melanoma cell lines. MITF expression in the tetracycline-inducible C32 melanoma model caused a marked increase in vesicular structures, and increased expression of late endosomal proteins, such as Rab7, LAMP1, and CD63. These late endosomes were not functional lysosomes as they were less active in proteolysis, yet were able to concentrate Axin1, phospho-LRP6, phospho-β-catenin, and GSK3 in the presence of Wnt ligands. This relocalization significantly enhanced Wnt signaling by increasing the number of multivesicular bodies into which the Wnt signalosome/destruction complex becomes localized upon Wnt signaling. We also show that the MITF protein was stabilized by Wnt signaling, through the novel C-terminal GSK3 phosphorylations identified here. MITF stabilization caused an increase in multivesicular body biosynthesis, which in turn increased Wnt signaling, generating a positive-feedback loop that may function during the proliferative stages of melanoma. The results underscore the importance of misregulated endolysosomal biogenesis in Wnt signaling and cancer. PMID:25605940

  16. Wnt5a signaling is a substantial constituent in bone morphogenetic protein-2-mediated osteoblastogenesis.

    Science.gov (United States)

    Nemoto, Eiji; Ebe, Yukari; Kanaya, Sousuke; Tsuchiya, Masahiro; Nakamura, Takashi; Tamura, Masato; Shimauchi, Hidetoshi

    2012-06-15

    Wnts are secreted glycoproteins that mediate developmental and post-developmental physiology by regulating cellular processes including proliferation, differentiation, and apoptosis through β-catenin-dependent canonical and β-catenin-independent noncanonical pathway. It has been reported that Wnt5a activates noncanonical Wnt signaling through receptor tyrosine kinase-like orphan receptor 2 (Ror2). Although it appears that Wnt5a/Ror2 signaling supports normal bone physiology, the biological significance of noncanonical Wnts in osteogenesis is essentially unknown. In this study, we identified expression of Wnt5a in osteoblasts in the ossification zone of the tibial growth plate as well as bone marrow of the rat tibia as assessed by immunohistochemistry. In addition, we show that osteoblastic differentiation mediated by BMP-2 is associated with increased expression of Wnt5a and Ror2 using cultured pre-osteoblasts, MC3T3-E1 cells. Silencing gene expression of Wnt5a and Ror2 in MC3T3-E1 cells results in suppression of BMP-2-mediated osteoblastic differentiation, suggesting that Wnt5a and Ror2 signaling are of substantial importance for BMP-2-mediated osteoblastic differentiation. BMP-2 stimulation induced phosphorylation of Smad1/5/8 in a similar fashion in both siWnt5a-treated cells and control cells, suggesting that Wnt5a was dispensable for the phosphorylation of Smads by BMP-2. Taken together, our results suggest that Wnt5a/Ror2 signaling appears to be involved in BMP-2-mediated osteoblast differentiation in a Smad independent pathway.

  17. Distinct Wnt signaling pathways have opposing roles in appendage regeneration.

    Science.gov (United States)

    Stoick-Cooper, Cristi L; Weidinger, Gilbert; Riehle, Kimberly J; Hubbert, Charlotte; Major, Michael B; Fausto, Nelson; Moon, Randall T

    2007-02-01

    In contrast to mammals, lower vertebrates have a remarkable capacity to regenerate complex structures damaged by injury or disease. This process, termed epimorphic regeneration, involves progenitor cells created through the reprogramming of differentiated cells or through the activation of resident stem cells. Wnt/beta-catenin signaling regulates progenitor cell fate and proliferation during embryonic development and stem cell function in adults, but its functional involvement in epimorphic regeneration has not been addressed. Using transgenic fish lines, we show that Wnt/beta-catenin signaling is activated in the regenerating zebrafish tail fin and is required for formation and subsequent proliferation of the progenitor cells of the blastema. Wnt/beta-catenin signaling appears to act upstream of FGF signaling, which has recently been found to be essential for fin regeneration. Intriguingly, increased Wnt/beta-catenin signaling is sufficient to augment regeneration, as tail fins regenerate faster in fish heterozygous for a loss-of-function mutation in axin1, a negative regulator of the pathway. Likewise, activation of Wnt/beta-catenin signaling by overexpression of wnt8 increases proliferation of progenitor cells in the regenerating fin. By contrast, overexpression of wnt5b (pipetail) reduces expression of Wnt/beta-catenin target genes, impairs proliferation of progenitors and inhibits fin regeneration. Importantly, fin regeneration is accelerated in wnt5b mutant fish. These data suggest that Wnt/beta-catenin signaling promotes regeneration, whereas a distinct pathway activated by wnt5b acts in a negative-feedback loop to limit regeneration.

  18. Loss of FTO antagonises Wnt signaling and leads to developmental defects associated with ciliopathies.

    Directory of Open Access Journals (Sweden)

    Daniel P S Osborn

    Full Text Available Common intronic variants in the Human fat mass and obesity-associated gene (FTO are found to be associated with an increased risk of obesity. Overexpression of FTO correlates with increased food intake and obesity, whilst loss-of-function results in lethality and severe developmental defects. Despite intense scientific discussions around the role of FTO in energy metabolism, the function of FTO during development remains undefined. Here, we show that loss of Fto leads to developmental defects such as growth retardation, craniofacial dysmorphism and aberrant neural crest cells migration in Zebrafish. We find that the important developmental pathway, Wnt, is compromised in the absence of FTO, both in vivo (zebrafish and in vitro (Fto(-/- MEFs and HEK293T. Canonical Wnt signalling is down regulated by abrogated β-Catenin translocation to the nucleus whilst non-canonical Wnt/Ca(2+ pathway is activated via its key signal mediators CaMKII and PKCδ. Moreover, we demonstrate that loss of Fto results in short, absent or disorganised cilia leading to situs inversus, renal cystogenesis, neural crest cell defects and microcephaly in Zebrafish. Congruently, Fto knockout mice display aberrant tissue specific cilia. These data identify FTO as a protein-regulator of the balanced activation between canonical and non-canonical branches of the Wnt pathway. Furthermore, we present the first evidence that FTO plays a role in development and cilia formation/function.

  19. Wnt Signaling in Renal Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Qi Xu

    2016-06-01

    Full Text Available Renal cell carcinoma (RCC accounts for 90% of all kidney cancers. Due to poor diagnosis, high resistance to the systemic therapies and the fact that most RCC cases occur sporadically, current research switched its focus on studying the molecular mechanisms underlying RCC. The aim is the discovery of new effective and less toxic anti-cancer drugs and novel diagnostic markers. Besides the PI3K/Akt/mTOR, HGF/Met and VHL/hypoxia cellular signaling pathways, the involvement of the Wnt/β-catenin pathway in RCC is commonly studied. Wnt signaling and its targeted genes are known to actively participate in different biological processes during embryonic development and renal cancer. Recently, studies have shown that targeting this pathway by alternating/inhibiting its intracellular signal transduction can reduce cancer cells viability and inhibit their growth. The targets and drugs identified show promising potential to serve as novel RCC therapeutics and prognostic markers. This review aims to summarize the current status quo regarding recent research on RCC focusing on the involvement of the Wnt/β-catenin pathway and how its understanding could facilitate the identification of potential therapeutic targets, new drugs and diagnostic biomarkers.

  20. R-spondin 3 regulates dorsoventral and anteroposterior patterning by antagonizing Wnt/β-catenin signaling in zebrafish embryos.

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    Xiaozhi Rong

    Full Text Available The Wnt/β-catenin or canonical Wnt signaling pathway plays fundamental roles in early development and in maintaining adult tissue homeostasis. R-spondin 3 (Rspo3 is a secreted protein that has been implicated in activating the Wnt/β-catenin signaling in amphibians and mammals. Here we report that zebrafish Rspo3 plays a negative role in regulating the zygotic Wnt/β-catenin signaling. Zebrafish Rspo3 has a unique domain structure. It contains a third furin-like (FU3 domain. This FU3 is present in other four ray-finned fish species studied but not in elephant shark. In zebrafish, rspo3 mRNA is maternally deposited and has a ubiquitous expression in early embryonic stages. After 12 hpf, its expression becomes tissue-specific. Forced expression of rspo3 promotes dorsoanterior patterning and increases the expression of dorsal and anterior marker genes. Knockdown of rspo3 increases ventral-posterior development and stimulates ventral and posterior marker genes expression. Forced expression of rspo3 abolishes exogenous Wnt3a action and reduces the endogenous Wnt signaling activity. Knockdown of rspo3 results in increased Wnt/β-catenin signaling activity. Further analyses indicate that Rspo3 does not promote maternal Wnt signaling. Human RSPO3 has similar action when tested in zebrafish embryos. These results suggest that Rspo3 regulates dorsoventral and anteroposterior patterning by negatively regulating the zygotic Wnt/β-catenin signaling in zebrafish embryos.

  1. Wnt5a signaling is a substantial constituent in bone morphogenetic protein-2-mediated osteoblastogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Eiji, E-mail: e-nemoto@dent.tohoku.ac.jp [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Ebe, Yukari; Kanaya, Sousuke [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tsuchiya, Masahiro [Department of Aging and Geriatric Dentistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Nakamura, Takashi [Department of Pediatric Dentistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tamura, Masato [Department of Biochemistry and Molecular Biology, Hokkaido University Graduate School of Dentistry, Sapporo 060-8586 (Japan); Shimauchi, Hidetoshi [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Wnt5a is identified in osteoblasts in tibial growth plate and bone marrow. Black-Right-Pointing-Pointer Osteoblastic differentiation is associated with increased expression of Wnt5a/Ror2. Black-Right-Pointing-Pointer Wnt5a/Ror2 signaling is important for BMP-2-mediated osteoblastic differentiation. Black-Right-Pointing-Pointer Wnt5a/Ror2 operates independently of BMP-Smad pathway. -- Abstract: Wnts are secreted glycoproteins that mediate developmental and post-developmental physiology by regulating cellular processes including proliferation, differentiation, and apoptosis through {beta}-catenin-dependent canonical and {beta}-catenin-independent noncanonical pathway. It has been reported that Wnt5a activates noncanonical Wnt signaling through receptor tyrosine kinase-like orphan receptor 2 (Ror2). Although it appears that Wnt5a/Ror2 signaling supports normal bone physiology, the biological significance of noncanonical Wnts in osteogenesis is essentially unknown. In this study, we identified expression of Wnt5a in osteoblasts in the ossification zone of the tibial growth plate as well as bone marrow of the rat tibia as assessed by immunohistochemistry. In addition, we show that osteoblastic differentiation mediated by BMP-2 is associated with increased expression of Wnt5a and Ror2 using cultured pre-osteoblasts, MC3T3-E1 cells. Silencing gene expression of Wnt5a and Ror2 in MC3T3-E1 cells results in suppression of BMP-2-mediated osteoblastic differentiation, suggesting that Wnt5a and Ror2 signaling are of substantial importance for BMP-2-mediated osteoblastic differentiation. BMP-2 stimulation induced phosphorylation of Smad1/5/8 in a similar fashion in both siWnt5a-treated cells and control cells, suggesting that Wnt5a was dispensable for the phosphorylation of Smads by BMP-2. Taken together, our results suggest that Wnt5a/Ror2 signaling appears to be involved in BMP-2-mediated osteoblast differentiation in a Smad independent

  2. A diterpenoid derivative 15-oxospiramilactone inhibits Wnt/β-catenin signaling and colon cancer cell tumorigenesis

    Institute of Scientific and Technical Information of China (English)

    Wei Wang; Haiyang Liu; Sheng Wang; Xiaojiang Hao; Lin Li

    2011-01-01

    The Wnt/β-catenin signaling pathway is a highly conserved pathway in organism evolution and regulates many biological processes. Aberrant activation of the Wnt/β-catenin signaling pathway is closely related to tumorigenesis.In order to identify potent small molecules to treat the over-activated Wnt signaling-mediated cancer, such as colon cancer, we established a mammalian cell line-based reporter gene screening system. The screen revealed a diterpenoid derivative, 15-oxospiramilactone(NC043)that inhibits Wnt3a or LiCl-stimulated Top-flash reporter activity in HEK293T cells and growth of colon cancer cells, SW480 and Caco-2. Treatment of SW480 cells with NC043 led to decreases in the mRNA and/or protein expression of Wnt target genes Axin2, Cyclin Dl and Survivin, as well as decreases in the protein levels of Cdc25c and Cdc2.NC043 did not affect the cytosol-nuclear distribution and protein level of soluble β-catenin, but decreased β-catenin/TCF4 association in SW480 cells. Moreover, NC043 inhibited anchorage-independent growth and xenograft tumorigenesis of SW480 cells. Collectively these results demonstrate that NC043 is a novel small molecule that inhibits canonical Wnt signaling downstream of P-catenin stability and may be a potential compound for treating colorectal cancer.

  3. Wnt5a Signals through DVL1 to Repress Ribosomal DNA Transcription by RNA Polymerase I

    Science.gov (United States)

    Dass, Randall A.; Sarshad, Aishe A.; Feenstra, Jennifer M.; Kaur, Amanpreet; Pietras, Kristian; Serra, Rosa; Blanchard, Scott C.; Percipalle, Piergiorgio; Brown, Anthony M. C.; Vincent, C. Theresa

    2016-01-01

    Ribosome biogenesis is essential for cell growth and proliferation and is commonly elevated in cancer. Accordingly, numerous oncogene and tumor suppressor signaling pathways target rRNA synthesis. In breast cancer, non-canonical Wnt signaling by Wnt5a has been reported to antagonize tumor growth. Here, we show that Wnt5a rapidly represses rDNA gene transcription in breast cancer cells and generates a chromatin state with reduced transcription of rDNA by RNA polymerase I (Pol I). These effects were specifically dependent on Dishevelled1 (DVL1), which accumulates in nucleolar organizer regions (NORs) and binds to rDNA regions of the chromosome. Upon DVL1 binding, the Pol I transcription activator and deacetylase Sirtuin 7 (SIRT7) releases from rDNA loci, concomitant with disassembly of Pol I transcription machinery at the rDNA promoter. These findings reveal that Wnt5a signals through DVL1 to suppress rRNA transcription. This provides a novel mechanism for how Wnt5a exerts tumor suppressive effects and why disruption of Wnt5a signaling enhances mammary tumor growth in vivo. PMID:27500936

  4. An HMG1-like protein facilitates Wnt signaling in Caenorhabditis elegans

    Science.gov (United States)

    Jiang, Lily I.; Sternberg, Paul W.

    1999-01-01

    We show that during Caenorhabditis elegans male spicule development, the specification of a glial versus neuronal cell fate in a canonical neurogenic sublineage is dependent on Wnt signaling. Inactivation of a Wnt signaling pathway mediated by the Wnt receptor LIN-17 transforms the SPD sheath cell into its sister, the SPD neuron. We discovered a new mutant, son-1, that displays this same cell fate transformation. The son-1 mutation enhances the phenotypes of reduction-of-function lin-17 mutants in several developmental processes, including vulva development, somatic gonad development, and male tail patterning. son-1 encodes an HMG1/2-like DNA-binding protein and is localized in all cell nuclei through development as revealed by a GFP reporter construct. Disruption of son-1 function by RNA-mediated interference results in the same spicule defect as caused by overexpression of POP-1, a TCF/LEF class HMG protein known to act downstream of the Wnt signaling pathway. Our results provide in vivo evidence for the functional involvement of an HMG1/2-like protein, SON-1, in Wnt signaling. The sequence nonspecific HMG protein SON-1 and the sequence specific HMG protein POP-1 might both act in the Wnt responding cells to regulate gene transcription in opposite directions. PMID:10197987

  5. Involvement of WNT/β-catenin signaling in the treatment of osteoporosis.

    Science.gov (United States)

    Rossini, Maurizio; Gatti, Davide; Adami, Silvano

    2013-08-01

    Osteoblast differentiation is predominantly regulated by the WNT/β-catenin signaling (canonical WNT pathway), which, together with bone morphogenetic proteins, acts as the master regulator of osteogenesis. The recent characterization of the canonical WNT pathway in the regulation of bone modeling and remodeling provided important insights for our understanding of the pathophysiology of a number of conditions and of the mechanism of action of hormones or drugs with important effect on bone metabolism. This review is mainly focused on the growing therapeutic implications of these new findings. WNT/β-catenin signaling plays a key role in bone tissue by determining the differentiation of stem cells into mature osteoblasts rather than into chondrocytes and adipocytes. Its regulation is predominantly driven by the production of two WNT signaling antagonists: sclerostin (SOST) and Dickkopf-related protein 1 (DKK1). The most proximate regulator of SOST expression by osteocytes and its serum levels is bone mechanical load. SOST expression is increased with advancing age, by glucocorticoid treatment and during treatment with antiresorptive agents such as bisphosphonates and denosumab, while it is decreased by parathyroid hormone excess or administration of estrogens. Correlation between DKK1 serum levels and bone formation in various pathological conditions or during osteoporosis treatment has been reported. Inhibitors of the negative regulators of WNT/β-catenin signaling ("inhibiting the endogenous inhibitors") are potential candidates for the prevention and treatment of bone loss. Inactivating monoclonal antibodies against SOST appears to be the most attractive strategy because SOST is the only component of the WNT pathway expressed almost exclusively by osteocytes.

  6. Mechanism of Wnt signaling induced down regulation of mrhl long non-coding RNA in mouse spermatogonial cells

    Science.gov (United States)

    Akhade, Vijay Suresh; Dighe, Shrinivas Nivrutti; Kataruka, Shubhangini; Rao, Manchanahalli R. Satyanarayana

    2016-01-01

    Long non coding RNAs (lncRNAs) have emerged as important regulators of various biological processes. LncRNAs also behave as response elements or targets of signaling pathway(s) mediating cellular function. Wnt signaling is important in regulating mammalian spermatogenesis. Mrhl RNA negatively regulates canonical Wnt pathway and gets down regulated upon Wnt signaling activation in mouse spermatogonial cells. Also, mrhl RNA regulates expression of genes pertaining to Wnt pathway and spermatogenesis by binding to chromatin. In the present study, we delineate the detailed molecular mechanism of Wnt signaling induced mrhl RNA down regulation in mouse spermatogonial cells. Mrhl RNA has an independent transcription unit and our various experiments like Chromatin Immunoprecipitation (in cell line as well as mouse testis) and shRNA mediated down regulation convincingly show that β-catenin and TCF4, which are the key effector proteins of the Wnt signaling pathway are required for down regulation of mrhl RNA. We have identified Ctbp1 as the co-repressor and its occupancy on mrhl RNA promoter depends on both β-catenin and TCF4. Upon Wnt signaling activation, Ctbp1 mediated histone repression marks increase at the mrhl RNA promoter. We also demonstrate that Wnt signaling induced mrhl RNA down regulation results in an up regulation of various meiotic differentiation marker genes. PMID:26446991

  7. WNT signalling pathways as therapeutic targets in cancer.

    Science.gov (United States)

    Anastas, Jamie N; Moon, Randall T

    2013-01-01

    Since the initial discovery of the oncogenic activity of WNT1 in mouse mammary glands, our appreciation for the complex roles for WNT signalling pathways in cancer has increased dramatically. WNTs and their downstream effectors regulate various processes that are important for cancer progression, including tumour initiation, tumour growth, cell senescence, cell death, differentiation and metastasis. Although WNT signalling pathways have been difficult to target, improved drug-discovery platforms and new technologies have facilitated the discovery of agents that can alter WNT signalling in preclinical models, thus setting the stage for clinical trials in humans.

  8. Therapeutic targets in the Wnt signaling pathway: Feasibility of targeting TNIK in colorectal cancer.

    Science.gov (United States)

    Masuda, Mari; Sawa, Masaaki; Yamada, Tesshi

    2015-12-01

    The genetic and epigenetic alterations occurring during the course of multistage colorectal carcinogenesis have been extensively studied in the last few decades. One of the most notable findings is that the great majority of colorectal cancers (>80%) have mutations in the adenomatous polyposis coli (APC) tumor suppressor gene. Loss of functional APC protein results in activation of canonical Wnt/β-catanin signaling and initiates intestinal carcinogenesis. Mutational inactivation of APC is the first genetic event, but colorectal cancer cells retain their dependency on constitutive Wnt signal activation even after accumulation of other genetic events. Accordingly, pharmacological blocking of Wnt signaling has been considered an attractive therapeutic approach for colorectal cancer. Several therapeutics targeting various molecular components of the Wnt signaling pathway, including porcupine, frizzled receptors and co-receptor, tankyrases, and cAMP response element binding protein (CREB)-binding protein (CBP), have been developed, and some of those are currently being evaluated in early-phase clinical trials. Traf2- and Nck-interacting protein kinase (TNIK) has been identified as a regulatory component of the T-cell factor-4 and β-catenin transcriptional complex independently by two research groups. TNIK regulates Wnt signaling in the most downstream part of the pathway, and its inhibition is expected to block the signal even in colorectal cancer cells with APC gene mutation. Here we discuss some of the TNIK inhibitors under preclinical development.

  9. Loss of Pancreas upon Activated Wnt Signaling Is Concomitant with Emergence of Gastrointestinal Identity

    Science.gov (United States)

    Herrero-Martin, Griselda; Puri, Sapna; Taketo, Makoto Mark; Rojas, Anabel; Hebrok, Matthias; Cano, David A.

    2016-01-01

    Organ formation is achieved through the complex interplay between signaling pathways and transcriptional cascades. The canonical Wnt signaling pathway plays multiple roles during embryonic development including patterning, proliferation and differentiation in distinct tissues. Previous studies have established the importance of this pathway at multiple stages of pancreas formation as well as in postnatal organ function and homeostasis. In mice, gain-of-function experiments have demonstrated that activation of the canonical Wnt pathway results in pancreatic hypoplasia, a phenomenon whose underlying mechanisms remains to be elucidated. Here, we show that ectopic activation of epithelial canonical Wnt signaling causes aberrant induction of gastric and intestinal markers both in the pancreatic epithelium and mesenchyme, leading to the development of gut-like features. Furthermore, we provide evidence that β -catenin-induced impairment of pancreas formation depends on Hedgehog signaling. Together, our data emphasize the developmental plasticity of pancreatic progenitors and further underscore the key role of precise regulation of signaling pathways to maintain appropriate organ boundaries. PMID:27736991

  10. DKK1 mediated inhibition of Wnt signaling in postnatal mice leads to loss of TEC progenitors and thymic degeneration.

    Directory of Open Access Journals (Sweden)

    Masako Osada

    Full Text Available BACKGROUND: Thymic epithelial cell (TEC microenvironments are essential for the recruitment of T cell precursors from the bone marrow, as well as the subsequent expansion and selection of thymocytes resulting in a mature self-tolerant T cell repertoire. The molecular mechanisms, which control both the initial development and subsequent maintenance of these critical microenvironments, are poorly defined. Wnt signaling has been shown to be important to the development of several epithelial tissues and organs. Regulation of Wnt signaling has also been shown to impact both early thymocyte and thymic epithelial development. However, early blocks in thymic organogenesis or death of the mice have prevented analysis of a role of canonical Wnt signaling in the maintenance of TECs in the postnatal thymus. METHODOLOGY/PRINCIPAL FINDINGS: Here we demonstrate that tetracycline-regulated expression of the canonical Wnt inhibitor DKK1 in TECs localized in both the cortex and medulla of adult mice, results in rapid thymic degeneration characterized by a loss of DeltaNP63(+ Foxn1(+ and Aire(+ TECs, loss of K5K8DP TECs thought to represent or contain an immature TEC progenitor, decreased TEC proliferation and the development of cystic structures, similar to an aged thymus. Removal of DKK1 from DKK1-involuted mice results in full recovery, suggesting that canonical Wnt signaling is required for the differentiation or proliferation of TEC populations needed for maintenance of properly organized adult thymic epithelial microenvironments. CONCLUSIONS/SIGNIFICANCE: Taken together, the results of this study demonstrate that canonical Wnt signaling within TECs is required for the maintenance of epithelial microenvironments in the postnatal thymus, possibly through effects on TEC progenitor/stem cell populations. Downstream targets of Wnt signaling, which are responsible for maintenance of these TEC progenitors may provide useful targets for therapies aimed at

  11. LMO2 attenuates tumor growth by targeting the Wnt signaling pathway in breast and colorectal cancer

    Science.gov (United States)

    Liu, Ye; Huang, Di; Wang, Zhaoyang; Wu, Chao; Zhang, Zhao; Wang, Dan; Li, Zongjin; Zhu, Tianhui; Yang, Shuang; Sun, Wei

    2016-01-01

    The proto-oncogene LIM-domain only 2 (lmo2) was traditionally considered to be a pivotal transcriptional regulator in hematopoiesis and leukemia. Recently, the cytosolic localization of LMO2 was revealed in multiple epithelial tissues and a variety of solid tumors. However, the function of LMO2 in these epithelia and solid tumors remains largely unclear. The Wnt signaling pathway is a crucial determinant of development, and abnormalities in several key segments of this pathway contribute to oncogenesis. The current study demonstrated that LMO2 participates in the regulation of canonical Wnt signaling in the cytoplasm by binding to Dishevelled-1/2 (DVL-1/2) proteins. These interactions occurred at the PDZ domain of Dishevelled, and LMO2 subsequently attenuated the activation of the key factor β-catenin in the canonical Wnt signaling pathway. Meanwhile, significantly decreased expression of LMO2 was detected in breast and colorectal cancers, and the downregulation of LMO2 in these cells increased cell proliferation and reduced apoptosis. Taken together, the data in this study revealed a novel crosstalk between LMO2 and the Wnt signaling pathway during tumorigenesis and suggested that LMO2 might be a tumor suppressor in certain solid tumors, in contrast to its traditional oncogenic role in the hematopoietic system. PMID:27779255

  12. IQGAP1 functions as a modulator of dishevelled nuclear localization in Wnt signaling.

    Directory of Open Access Journals (Sweden)

    Toshiyasu Goto

    Full Text Available Dishevelled (DVL is a central factor in the Wnt signaling pathway, which is highly conserved among various organisms. DVL plays important roles in transcriptional activation in the nucleus, but the molecular mechanisms underlying their nuclear localization remain unclear. In the present study, we identified IQGAP1 as a regulator of DVL function. In Xenopus embryos, depletion of IQGAP1 reduced Wnt-induced nuclear accumulation of DVL, and expression of Wnt target genes during early embryogenesis. The domains in DVL and IQGAP1 that mediated their interaction are also required for their nuclear localization. Endogenous expression of Wnt target genes was reduced by depletion of IQGAP1 during early embryogenesis, but notably not by depletion of other IQGAP family genes. Moreover, expression of Wnt target genes caused by depletion of endogenous IQGAP1 could be rescued by expression of wild-type IQGAP1, but not IQGAP1 deleting DVL binding region. These results provide the first evidence that IQGAP1 functions as a modulator in the canonical Wnt signaling pathway.

  13. Integration of Shh and Wnt Signaling Pathways Regulating Hematopoiesis.

    Science.gov (United States)

    Zhou, Zhigang; Wan, Liping; Wang, Chun; Zhou, Kun

    2015-12-01

    To investigate the spatial and temporal programmed expression of Shh and Wnt members during key stages of definitive hematopoiesis and the possible mechanism of Shh and Wnt signaling pathways regulating the proliferation of hematopoietic progenitor cells (HPCs). Spatial and temporal programmed gene expression of Shh and Wnt signaling during hematopoiesis corresponded with c-kit(+)lin(-) HPCs proliferation. C-kit(+)Lin(-) populations derived from aorta-gonad-mesonephros (AGM) of Balb/c mice at E10.5 with increased expression of Shh and Wnt3a demonstrated a greater potential for proliferation. Additionally, supplementation with soluble Shh N-terminal peptide promoted the proliferation of c-kit(+)Lin(-) populations by activating the Wnt signaling pathway, an effect which was inhibited by blocking Shh signaling. A specific inhibitor of wnt signaling was capable of inhibiting Shh-induced proliferation in a similar manner to shh inhibitor. Our results provide valuable information on Shh and Wnt signaling involved in hematopoiesis and highlight the importance of interaction of Shh and Wnt signaling in regulating HPCs proliferation.

  14. Wnt5a attenuates Wnt3a-induced alkaline phosphatase expression in dental follicle cells

    Energy Technology Data Exchange (ETDEWEB)

    Sakisaka, Yukihiko [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tsuchiya, Masahiro [Department of Oral Diagnosis, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tohoku Fukushi University, Sendai 989-3201 (Japan); Nakamura, Takashi [Department of Pediatric Dentistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Liason Center for Innovative Dentistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tamura, Masato [Department of Biochemistry and Molecular Biology, Hokkaido University Graduate School of Dentistry, Sapporo 060-8586 (Japan); Shimauchi, Hidetoshi [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Nemoto, Eiji, E-mail: e-nemoto@dent.tohoku.ac.jp [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan)

    2015-08-01

    Wnt signaling regulates multiple cellular events such as cell proliferation, differentiation, and apoptosis through β-catenin-dependent canonical and β-catenin-independent noncanonical pathways. Canonical Wnt/β-catenin signaling can promote the differentiation of dental follicle cells, putative progenitor cells for cementoblasts, osteoblasts, and periodontal ligament cells, toward a cementoblast/osteoblast phenotype during root formation, but little is known about the biological significance of noncanonical Wnt signaling in this process. We identified the expression of Wnt5a, a representative noncanonical Wnt ligand, in tooth root lining cells (i.e. precementoblasts/cementoblasts) and dental follicle cells during mouse tooth root development, as assessed by immunohistochemistry. Silencing expression of the Wnt5a gene in a dental follicle cell line resulted in enhancement of the Wnt3a (a representative canonical Wnt ligand)-mediated increase in alkaline phosphatase (ALP) expression. Conversely, treatment with recombinant Wnt5a inhibited the increase in ALP expression, suggesting that Wnt5a signaling functions as a negative regulator of canonical Wnt-mediated ALP expression of dental follicle cells. Wnt5a did not affect the nuclear translocation of β-catenin as well as β-catenin-mediated transcriptional activation of T-cell factor (Tcf) triggered by Wnt3a, suggesting that Wnt5a inhibits the downstream part of the β-catenin-Tcf pathway. These findings suggest the existence of a feedback mechanism between canonical and noncanonical Wnt signaling during the differentiation of dental follicle cells. - Highlights: • Dental follicle cells express Wnt5a during tooth root development. • Silencing of Wnt5a enhances Wnt3a-mediated ALP expression of dental follicle cells. • Conversely, treatment with rWnt5a inhibited the increase in ALP expression. • Wnt5a functions as a negative regulator of Wnt3a-mediated ALP expression.

  15. Crosstalk between Wnt Signaling and RNA Processing in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Michael Bordonaro

    2013-01-01

    Full Text Available RNA processing involves a variety of processes affecting gene expression, including the removal of introns through RNA splicing, as well as 3' end processing (cleavage and polyadenylation. Alternative RNA processing is fundamentally important for gene regulation, and aberrant processing is associated with the initiation and progression of cancer. Deregulated Wnt signaling, which is the initiating event in the development of most cases of human colorectal cancer (CRC, has been linked to modified RNA processing, which may contribute to Wnt-mediated colonic carcinogenesis. Crosstalk between Wnt signaling and alternative RNA splicing with relevance to CRC includes effects on the expression of Rac1b, an alternatively spliced gene associated with tumorigenesis, which exhibits alternative RNA splicing that is influenced by Wnt activity. In addition, Tcf4, a crucial component of Wnt signaling, also exhibits alternative splicing, which is likely involved in colonic tumorigenesis. Modulation of 3' end formation, including of the Wnt target gene COX-2, also can influence the neoplastic process, with implications for CRC. While many human genes are dependent on introns and splicing for normal levels of gene expression, naturally intronless genes exist with a unique metabolism that allows for intron-independent gene expression. Effects of Wnt activity on the RNA metabolism of the intronless Wnt-target gene c-jun is a likely contributor to cancer development. Further, butyrate, a breakdown product of dietary fiber and a histone deacetylase inhibitor, upregulates Wnt activity in CRC cells, and also modulates RNA processing; therefore, the interplay between Wnt activity, the modulation of this activity by butyrate, and differential RNA metabolism in colonic cells can significantly influence tumorigenesis. Determining the role played by altered RNA processing in Wnt-mediated neoplasia may lead to novel interventions aimed at restoring normal RNA metabolism for

  16. WNT signaling in the normal intestine and colorectal cancer.

    NARCIS (Netherlands)

    Lau, W. de; Barker, N.; Clevers, J.C.

    2007-01-01

    The intestinal epithelium is a self-renewing tissue that represents a unique model for studying interconnected cellular processes such as proliferation, differentiation, cell migration and carcinogenesis. This review covers work from the past decade and highlights the importance of the canonical Wnt

  17. Functional Wnt signaling is increased in idiopathic pulmonary fibrosis.

    Directory of Open Access Journals (Sweden)

    Melanie Königshoff

    Full Text Available BACKGROUND: Idiopathic pulmonary fibrosis (IPF is a fatal lung disease, characterized by distorted lung architecture and loss of respiratory function. Alveolar epithelial cell injury and hyperplasia, enhanced extracellular matrix deposition, and (myofibroblast activation are features of IPF. Wnt/beta-catenin signaling has been shown to determine epithelial cell fate during development. As aberrant reactivation of developmental signaling pathways has been suggested to contribute to IPF pathogenesis, we hypothesized that Wnt/beta-catenin signaling is activated in epithelial cells in IPF. Thus, we quantified and localized the expression and activity of the Wnt/beta-catenin pathway in IPF. METHODOLOGY/PRINCIPAL FINDINGS: The expression of Wnt1, 3a, 7b, and 10b, the Wnt receptors Fzd1-4, Lrp5-6, as well as the intracellular signal transducers Gsk-3beta, beta-catenin, Tcf1, 3, 4, and Lef1 was analyzed in IPF and transplant donor lungs by quantitative real-time (qRT-PCR. Wnt1, 7b and 10b, Fzd2 and 3, beta-catenin, and Lef1 expression was significantly increased in IPF. Immunohistochemical analysis localized Wnt1, Wnt3a, beta-catenin, and Gsk-3beta expression largely to alveolar and bronchial epithelium. This was confirmed by qRT-PCR of primary alveolar epithelial type II (ATII cells, demonstrating a significant increase of Wnt signaling in ATII cells derived from IPF patients. In addition, Western blot analysis of phospho-Gsk-3beta, phospho-Lrp6, and beta-catenin, and qRT-PCR of the Wnt target genes cyclin D1, Mmp 7, or Fibronectin 1 demonstrated increased functional Wnt/beta-catenin signaling in IPF compared with controls. Functional in vitro studies further revealed that Wnt ligands induced lung epithelial cell proliferation and (myofibroblast activation and collagen synthesis. CONCLUSIONS/SIGNIFICANCE: Our study demonstrates that the Wnt/beta-catenin pathway is expressed and operative in adult lung epithelium. Increased Wnt/beta-catenin signaling

  18. Cross-talk between insulin and Wnt signaling in preadipocytes

    DEFF Research Database (Denmark)

    Palsgaard, Jane; Emanuelli, Brice; Winnay, Jonathon N;

    2012-01-01

    Disturbed Wnt signaling has been implicated in numerous diseases, including type 2 diabetes and the metabolic syndrome. In the present study, we have investigated cross-talk between insulin and Wnt signaling pathways using preadipocytes with and without knockdown of the Wnt co-receptors LRP5...... and LRP6 and with and without knock-out of insulin and IGF-1 receptors. We find that Wnt stimulation leads to phosphorylation of insulin signaling key mediators, including Akt, GSK3β, and ERK1/2, although with a lower fold stimulation and slower time course than observed for insulin. These Wnt effects...... are insulin/IGF-1 receptor-dependent and are lost in insulin/IGF-1 receptor double knock-out cells. Conversely, in LRP5 knockdown preadipocytes, insulin-induced phosphorylation of IRS1, Akt, GSK3β, and ERK1/2 is highly reduced. This effect is specific to insulin, as compared with IGF-1, stimulation...

  19. Wnt Signaling Is Required for Long-Term Memory Formation

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    Ying Tan

    2013-09-01

    Full Text Available Wnt signaling regulates synaptic plasticity and neurogenesis in the adult nervous system, suggesting a potential role in behavioral processes. Here, we probed the requirement for Wnt signaling during olfactory memory formation in Drosophila using an inducible RNAi approach. Interfering with β-catenin expression in adult mushroom body neurons specifically impaired long-term memory (LTM without altering short-term memory. The impairment was reversible, being rescued by expression of a wild-type β-catenin transgene, and correlated with disruption of a cellular LTM trace. Inhibition of wingless, a Wnt ligand, and arrow, a Wnt coreceptor, also impaired LTM. Wingless expression in wild-type flies was transiently elevated in the brain after LTM conditioning. Thus, inhibiting three key components of the Wnt signaling pathway in adult mushroom bodies impairs LTM, indicating that this pathway mechanistically underlies this specific form of memory.

  20. Plakophilin-1, a Novel Wnt Signaling Regulator, Is Critical for Tooth Development and Ameloblast Differentiation.

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    Kanako Miyazaki

    Full Text Available Tooth morphogenesis is initiated by reciprocal interactions between the ectoderm and neural crest-derived mesenchyme, and the Wnt signaling pathway is involved in this process. We found that Plakophilin (PKP1, which is associated with diseases such as ectodermal dysplasia/skin fragility syndrome, was highly expressed in teeth and skin, and was upregulated during tooth development. We hypothesized that PKP1 regulates Wnt signaling via its armadillo repeat domain in a manner similar to β-catenin. To determine its role in tooth development, we performed Pkp1 knockdown experiments using ex vivo organ cultures and cell cultures. Loss of Pkp1 reduced the size of tooth germs and inhibited dental epithelial cell proliferation, which was stimulated by Wnt3a. Furthermore, transfected PKP1-emerald green fluorescent protein was translocated from the plasma membrane to the nucleus upon stimulation with Wnt3a and LiCl, which required the PKP1 N terminus (amino acids 161 to 270. Localization of PKP1, which is known as an adhesion-related desmosome component, shifted to the plasma membrane during ameloblast differentiation. In addition, Pkp1 knockdown disrupted the localization of Zona occludens 1 in tight junctions and inhibited ameloblast differentiation; the two proteins were shown to directly interact by immunoprecipitation. These results implicate the participation of PKP1 in early tooth morphogenesis as an effector of canonical Wnt signaling that controls ameloblast differentiation via regulation of the cell adhesion complex.

  1. An Lmx1b-miR135a2 regulatory circuit modulates Wnt1/Wnt signaling and determines the size of the midbrain dopaminergic progenitor pool.

    Directory of Open Access Journals (Sweden)

    Angela Anderegg

    Full Text Available MicroRNAs regulate gene expression in diverse physiological scenarios. Their role in the control of morphogen related signaling pathways has been less studied, particularly in the context of embryonic Central Nervous System (CNS development. Here, we uncover a role for microRNAs in limiting the spatiotemporal range of morphogen expression and function. Wnt1 is a key morphogen in the embryonic midbrain, and directs proliferation, survival, patterning and neurogenesis. We reveal an autoregulatory negative feedback loop between the transcription factor Lmx1b and a newly characterized microRNA, miR135a2, which modulates the extent of Wnt1/Wnt signaling and the size of the dopamine progenitor domain. Conditional gain of function studies reveal that Lmx1b promotes Wnt1/Wnt signaling, and thereby increases midbrain size and dopamine progenitor allocation. Conditional removal of Lmx1b has the opposite effect, in that expansion of the dopamine progenitor domain is severely compromised. Next, we provide evidence that microRNAs are involved in restricting dopamine progenitor allocation. Conditional loss of Dicer1 in embryonic stem cells (ESCs results in expanded Lmx1a/b+ progenitors. In contrast, forced elevation of miR135a2 during an early window in vivo phenocopies the Lmx1b conditional knockout. When En1::Cre, but not Shh::Cre or Nes::Cre, is used for recombination, the expansion of Lmx1a/b+ progenitors is selectively reduced. Bioinformatics and luciferase assay data suggests that miR135a2 targets Lmx1b and many genes in the Wnt signaling pathway, including Ccnd1, Gsk3b, and Tcf7l2. Consistent with this, we demonstrate that this mutant displays reductions in the size of the Lmx1b/Wnt1 domain and range of canonical Wnt signaling. We posit that microRNA modulation of the Lmx1b/Wnt axis in the early midbrain/isthmus could determine midbrain size and allocation of dopamine progenitors. Since canonical Wnt activity has recently been recognized as a key

  2. Wnt signaling induces epithelial differentiation during cutaneous wound healing

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    Hocking Anne

    2006-01-01

    Full Text Available Abstract Background Cutaneous wound repair in adult mammals does not regenerate the original epithelial architecture and results in altered skin function. We propose that lack of regeneration may be due to the absence of appropriate molecular signals to promote regeneration. In this study, we investigated the regulation of Wnt signaling during cutaneous wound healing and the consequence of activating either the beta-catenin-dependent or beta-catenin-independent Wnt signaling on epidermal architecture during wound repair. Results We determined that the expression of Wnt ligands that typically signal via the beta-catenin-independent pathway is up-regulated in the wound while the beta-catenin-dependent Wnt signaling is activated in the hair follicles adjacent to the wound edge. Ectopic activation of beta-catenin-dependent Wnt signaling with lithium chloride in the wound resulted in epithelial cysts and occasional rudimentary hair follicle structures within the epidermis. In contrast, forced expression of Wnt-5a in the deeper wound induced changes in the interfollicular epithelium mimicking regeneration, including formation of epithelia-lined cysts in the wound dermis, rudimentary hair follicles and sebaceous glands, without formation of tumors. Conclusion These findings suggest that adult interfollicular epithelium is capable of responding to Wnt morphogenic signals necessary for restoring epithelial tissue patterning in the skin during wound repair.

  3. Bone morphogenetic protein 2-induced human dental pulp cell differentiation involves p38 mitogen-activated protein kinase-activated canonical WNT pathway

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Ling Ye; Tian-Qian Hui; Dong-Mei Yang; Ding-Ming Huang; Xue-Dong Zhou; Jeremy J Mao; Cheng-Lin Wang

    2015-01-01

    Both bone morphogenetic protein 2 (BMP2) and the wingless-type MMTV integration site (WNT)/b-catenin signalling pathway play important roles in odontoblast differentiation and dentinogenesis. Cross-talk between BMP2 and WNT/b-catenin in osteoblast differentiation and bone formation has been identified. However, the roles and mechanisms of the canonical WNT pathway in the regulation of BMP2 in dental pulp injury and repair remain largely unknown. Here, we demonstrate that BMP2 promotes the differentiation of human dental pulp cells (HDPCs) by activating WNT/b-catenin signalling, which is further mediated by p38 mitogen-activated protein kinase (MAPK) in vitro. BMP2 stimulation upregulated the expression of b-catenin in HDPCs, which was abolished by SB203580 but not by Noggin or LDN193189. Furthermore, BMP2 enhanced cell differentiation, which was not fully inhibited by Noggin or LDN193189. Instead, SB203580 partially blocked BMP2-induced b-catenin expression and cell differentiation. Taken together, these data suggest a possible mechanism by which the elevation of b-catenin resulting from BMP2 stimulation is mediated by the p38 MAPK pathway, which sheds light on the molecular mechanisms of BMP2-mediated pulp reparative dentin formation.

  4. FHL2 silencing reduces Wnt signaling and osteosarcoma tumorigenesis in vitro and in vivo.

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    Julia Brun

    Full Text Available BACKGROUND: The molecular mechanisms that are involved in the growth and invasiveness of osteosarcoma, an aggressive and invasive primary bone tumor, are not fully understood. The transcriptional co-factor FHL2 (four and a half LIM domains protein 2 acts as an oncoprotein or as a tumor suppressor depending on the tissue context. In this study, we investigated the role of FHL2 in tumorigenesis in osteosarcoma model. METHODOLOGY/PRINCIPAL FINDINGS: Western blot analyses showed that FHL2 is expressed above normal in most human and murine osteosarcoma cells. Tissue microarray analysis revealed that FHL2 protein expression is high in human osteosarcoma and correlates with osteosarcoma aggressiveness. In murine osteosarcoma cells, FHL2 silencing using shRNA decreased canonical Wnt/β-catenin signaling and reduced the expression of Wnt responsive genes as well as of the key Wnt molecules Wnt5a and Wnt10b. This effect resulted in inhibition of osteosarcoma cell proliferation, invasion and migration in vitro. Using xenograft experiments, we showed that FHL2 silencing markedly reduced tumor growth and lung metastasis occurence in mice. The anti-oncogenic effect of FHL2 silencing in vivo was associated with reduced cell proliferation and decreased Wnt signaling in the tumors. CONCLUSION/SIGNIFICANCE: Our findings demonstrate that FHL2 acts as an oncogene in osteosarcoma cells and contributes to tumorigenesis through Wnt signaling. More importantly, FHL2 depletion greatly reduces tumor cell growth and metastasis, which raises the potential therapeutic interest of targeting FHL2 to efficiently impact primary bone tumors.

  5. Wnt Signaling Translocates Lys48-Linked Polyubiquitinated Proteins to the Lysosomal Pathway

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    Hyunjoon Kim

    2015-05-01

    Full Text Available Cellular proteins are degraded in either proteasomes or lysosomes depending on the types of ubiquitin chains that covalently modify them. It is not known whether the choice between these two pathways is physiologically regulated. The Lys48-polyubiquitin chain is the major signal directing proteins for degradation in proteasomes. Here, we report the unexpected finding that canonical Wnt signaling translocates some K48-linked polyubiquitinated proteins to the endolysosomal pathway. Proteasomal target proteins, such as β-catenin, Smad1, and Smad4, were targeted into endolysosomes in a process dependent on GSK3 activity. Relocalization was also dependent on Axin1 and the multivesicular body (MVB proteins HRS/Vps27 and Vps4. The Wnt-induced accumulation of K48-linked polyubiquitinated proteins in endolysosomal organelles was accompanied by a transient decrease in cellular levels of free mono-ubiquitin, which may contribute to Wnt-regulated stabilization of proteins (Wnt/STOP. We conclude that Wnt redirects Lys48-polyubiquitinated proteins that are normally degraded in proteasomes to endolysosomes.

  6. Distinct transcriptional networks in quiescent myoblasts: a role for Wnt signaling in reversible vs. irreversible arrest.

    Science.gov (United States)

    Subramaniam, Sindhu; Sreenivas, Prethish; Cheedipudi, Sirisha; Reddy, Vatrapu Rami; Shashidhara, Lingadahalli Subrahmanya; Chilukoti, Ravi Kumar; Mylavarapu, Madhavi; Dhawan, Jyotsna

    2014-01-01

    Most cells in adult mammals are non-dividing: differentiated cells exit the cell cycle permanently, but stem cells exist in a state of reversible arrest called quiescence. In damaged skeletal muscle, quiescent satellite stem cells re-enter the cell cycle, proliferate and subsequently execute divergent programs to regenerate both post-mitotic myofibers and quiescent stem cells. The molecular basis for these alternative programs of arrest is poorly understood. In this study, we used an established myogenic culture model (C2C12 myoblasts) to generate cells in alternative states of arrest and investigate their global transcriptional profiles. Using cDNA microarrays, we compared G0 myoblasts with post-mitotic myotubes. Our findings define the transcriptional program of quiescent myoblasts in culture and establish that distinct gene expression profiles, especially of tumour suppressor genes and inhibitors of differentiation characterize reversible arrest, distinguishing this state from irreversibly arrested myotubes. We also reveal the existence of a tissue-specific quiescence program by comparing G0 C2C12 myoblasts to isogenic G0 fibroblasts (10T1/2). Intriguingly, in myoblasts but not fibroblasts, quiescence is associated with a signature of Wnt pathway genes. We provide evidence that different levels of signaling via the canonical Wnt pathway characterize distinct cellular states (proliferation vs. quiescence vs. differentiation). Moderate induction of Wnt signaling in quiescence is associated with critical properties such as clonogenic self-renewal. Exogenous Wnt treatment subverts the quiescence program and negatively affects clonogenicity. Finally, we identify two new quiescence-induced regulators of canonical Wnt signaling, Rgs2 and Dkk3, whose induction in G0 is required for clonogenic self-renewal. These results support the concept that active signal-mediated regulation of quiescence contributes to stem cell properties, and have implications for pathological

  7. Wnt signaling in gut development and homeostasis

    NARCIS (Netherlands)

    Gregorieff, A.

    2006-01-01

    The Wnt pathway controls diverse biological processes during embryonic development. In the adult, Wnts maintain the balance between cell division and cell specialisation in tissues such as the hemapoetic system, skin, and the intestine. Genetic modifications which activate the Wnt pathway are also c

  8. Deranged Wnt signaling is frequent in hereditary nonpolyposis colorectal cancer

    DEFF Research Database (Denmark)

    Isinger-Ekstrand, Anna; Therkildsen, Christina; Bernstein, Inge;

    2011-01-01

    The Wnt signaling pathway is frequently deranged in colorectal cancer and is a key target for future preventive and therapeutic approaches. Colorectal cancers associated with the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome are characterized by wide-spread microsatellite instability...

  9. Understanding Wnt/b-catenin signaling in development and cancer

    Institute of Scientific and Technical Information of China (English)

    Xi He

    2008-01-01

    @@ The Wnt/beta-catenin signaling pathway plays key roles in development and diseases. This pathway requires two distinct receptors-a Frizzled serpentine receptor and LDL receptor related protein 5 or 6(LRP5 or LRP6).

  10. Epsin is required for Dishevelled stability and Wnt signalling activation in colon cancer development.

    Science.gov (United States)

    Chang, Baojun; Tessneer, Kandice L; McManus, John; Liu, Xiaolei; Hahn, Scott; Pasula, Satish; Wu, Hao; Song, Hoogeun; Chen, Yiyuan; Cai, Xiaofeng; Dong, Yunzhou; Brophy, Megan L; Rahman, Ruby; Ma, Jian-Xing; Xia, Lijun; Chen, Hong

    2015-03-16

    Uncontrolled canonical Wnt signalling supports colon epithelial tumour expansion and malignant transformation. Understanding the regulatory mechanisms involved is crucial for elucidating the pathogenesis of and will provide new therapeutic targets for colon cancer. Epsins are ubiquitin-binding adaptor proteins upregulated in several human cancers; however, the involvement of epsins in colon cancer is unknown. Here we show that loss of intestinal epithelial epsins protects against colon cancer by significantly reducing the stability of the crucial Wnt signalling effector, dishevelled (Dvl2), and impairing Wnt signalling. Consistently, epsins and Dvl2 are correspondingly upregulated in colon cancer. Mechanistically, epsin binds Dvl2 via its epsin N-terminal homology domain and ubiquitin-interacting motifs and prohibits Dvl2 polyubiquitination and degradation. Our findings reveal an unconventional role for epsins in stabilizing Dvl2 and potentiating Wnt signalling in colon cancer cells to ensure robust colon cancer progression. The pro-carcinogenic role of Epsins suggests that they are potential therapeutic targets to combat colon cancer.

  11. Wnt signaling activates Shh signaling in early postnatal intervertebral discs, and re-activates Shh signaling in old discs in the mouse.

    Science.gov (United States)

    Winkler, Tamara; Mahoney, Eric J; Sinner, Debora; Wylie, Christopher C; Dahia, Chitra Lekha

    2014-01-01

    Intervertebral discs (IVDs) are strong fibrocartilaginous joints that connect adjacent vertebrae of the spine. As discs age they become prone to failure, with neurological consequences that are often severe. Surgical repair of discs treats the result of the disease, which affects as many as one in seven people, rather than its cause. An ideal solution would be to repair degenerating discs using the mechanisms of their normal differentiation. However, these mechanisms are poorly understood. Using the mouse as a model, we previously showed that Shh signaling produced by nucleus pulposus cells activates the expression of differentiation markers, and cell proliferation, in the postnatal IVD. In the present study, we show that canonical Wnt signaling is required for the expression of Shh signaling targets in the IVD. We also show that Shh and canonical Wnt signaling pathways are down-regulated in adult IVDs. Furthermore, this down-regulation is reversible, since re-activation of the Wnt or Shh pathways in older discs can re-activate molecular markers of the IVD that are lost with age. These data suggest that biological treatments targeting Wnt and Shh signaling pathways may be feasible as a therapeutic for degenerative disc disease.

  12. LGR5 regulates pro-survival MEK/ERK and proliferative Wnt/β-catenin signalling in neuroblastoma.

    Science.gov (United States)

    Vieira, Gabriella Cunha; Chockalingam, S; Melegh, Zsombor; Greenhough, Alexander; Malik, Sally; Szemes, Marianna; Park, Ji Hyun; Kaidi, Abderrahmane; Zhou, Li; Catchpoole, Daniel; Morgan, Rhys; Bates, David O; Gabb, Peter David; Malik, Karim

    2015-11-24

    LGR5 is a marker of normal and cancer stem cells in various tissues where it functions as a receptor for R-spondins and increases canonical Wnt signalling amplitude. Here we report that LGR5 is also highly expressed in a subset of high grade neuroblastomas. Neuroblastoma is a clinically heterogenous paediatric cancer comprising a high proportion of poor prognosis cases (~40%) which are frequently lethal. Unlike many cancers, Wnt pathway mutations are not apparent in neuroblastoma, although previous microarray analyses have implicated deregulated Wnt signalling in high-risk neuroblastoma. We demonstrate that LGR5 facilitates high Wnt signalling in neuroblastoma cell lines treated with Wnt3a and R-spondins, with SK-N-BE(2)-C, SK-N-NAS and SH-SY5Y cell-lines all displaying strong Wnt induction. These lines represent MYCN-amplified, NRAS and ALK mutant neuroblastoma subtypes respectively. Wnt3a/R-Spondin treatment also promoted nuclear translocation of β-catenin, increased proliferation and activation of Wnt target genes. Strikingly, short-interfering RNA mediated knockdown of LGR5 induces dramatic Wnt-independent apoptosis in all three cell-lines, accompanied by greatly diminished phosphorylation of mitogen/extracellular signal-regulated kinases (MEK1/2) and extracellular signal-regulated kinases (ERK1/2), and an increase of BimEL, an apoptosis facilitator downstream of ERK. Akt signalling is also decreased by a Rictor dependent, PDK1-independent mechanism. LGR5 expression is cell cycle regulated and LGR5 depletion triggers G1 cell-cycle arrest, increased p27 and decreased phosphorylated retinoblastoma protein. Our study therefore characterises new cancer-associated pathways regulated by LGR5, and suggest that targeting of LGR5 may be of therapeutic benefit for neuroblastomas with diverse etiologies, as well as other cancers expressing high LGR5.

  13. The Notch-2 gene is regulated by Wnt signaling in cultured colorectal cancer cells.

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    Jonas Ungerbäck

    Full Text Available BACKGROUND: Notch and Wnt pathways are key regulators of intestinal homeostasis and alterations in these pathways may lead to the development of colorectal cancer (CRC. In CRC the Apc/β-catenin genes in the Wnt signaling pathway are frequently mutated and active Notch signaling contributes to tumorigenesis by keeping the epithelial cells in a proliferative state. These pathways are simultaneously active in proliferative adenoma cells and a crosstalk between them has previously been suggested in normal development as well as in cancer. PRINCIPAL FINDINGS: In this study, in silico analysis of putative promoters involved in transcriptional regulation of genes coding for proteins in the Notch signaling pathway revealed several putative LEF-1/TCF sites as potential targets for β-catenin and canonical Wnt signaling. Further results from competitive electrophoretic mobility-shift assay (EMSA studies suggest binding of several putative sites in Notch pathway gene promoters to in vitro translated β-catenin/Lef-1. Wild type (wt-Apc negatively regulates β-catenin. By induction of wt-Apc or β-catenin silencing in HT29 cells, we observed that several genes in the Notch pathway, including Notch-2, were downregulated. Finally, active Notch signaling was verified in the Apc(Min/+ mouse model where Hes-1 mRNA levels were found significantly upregulated in intestinal tumors compared to normal intestinal mucosa. Luciferase assays showed an increased activity for the core and proximal Notch-2 promoter upon co-transfection of HCT116 cells with high expression recombinant Tcf-4, Lef-1 or β-catenin. CONCLUSIONS: In this paper, we identified Notch-2 as a novel target for β-catenin-dependent Wnt signaling. Furthermore our data supports the notion that additional genes in the Notch pathway might be transcriptionally regulated by Wnt signaling in colorectal cancer.

  14. Wnt signaling induces differentiation of progenitor cells in organotypic keratinocyte cultures

    Directory of Open Access Journals (Sweden)

    Liu Bob Y

    2007-02-01

    Full Text Available Abstract Background Interfollicular skin develops normally only when the activity of the progenitor cells in the basal layer is counterbalanced by the exit of cells into the suprabasal layers, where they differentiate and cornify to establish barrier function. Distinct stem and progenitor compartments have been demonstrated in hair follicles and sebaceous glands, but there are few data to describe the control of interfollicular progenitor cell activity. Wnt signaling has been shown to be an important growth-inducer of stem cell compartments in skin and many other tissues. Results Here, we test the effect of ectopic Wnt1 expression on the behavior of interfollicular progenitor cells in an organotypic culture model, and find that Wnt1 signaling inhibits their growth and promotes terminal differentiation. Conclusion These results are consistent with the phenotypes reported for transgenic mice engineered to have gain or loss of function of Wnt signaling in skin, which would recommend our culture model as an accurate one for molecular analysis. Since it is known that canonical ligands are expressed in skin, it is likely that this pathway normally regulates the balance of growth and differentiation, and suggests it could be important to pathogenesis.

  15. Gpr177-mediated Wnt Signaling is Required for Fungiform Placode Initiation.

    Science.gov (United States)

    Zhu, X; Liu, Y; Zhao, P; Dai, Z; Yang, X; Li, Y; Qiu, M; Zhang, Z

    2014-06-01

    Fungiform papillae are formed as patterned rows on the surface of the anterior tongue at early organogenesis and contain one taste bud in each papilla to form one of the important sensory organs. Despite the essential role of Wnt/β-catenin signaling in controlling the development of fungiform taste papillae, the universal function of Wnt ligands in the initiation of the fungiform placode has not been completely elucidated. Here, by Shh (Cre) -mediated oral epithelial deletion of Wntless (Gpr177), a regulator essential for intracellular Wnt trafficking, we demonstrate that an overall function of Wnts is required for initiation of the fungiform placode. Multiple Wnts are expressed in the tongue epithelium at E11.5 before initiation of the fungiform placodes. Epithelial Gpr177 loss-of-function, associated with reduction of canonical Wnt signaling in lingual epithelium as exhibited by a loss of TopGal activity and Axin2 expression, results in the failure of fungiform placode initiation, as assessed by diminished expression of several taste placode molecular markers. Moreover, LiCl treatment of Gpr177 epithelial-deficient tongue explants at E11.5, but not at E12.5, restores tongue placode formation, demonstrating that Wnt ligands in the tongue surface prior to but not after fungiform placode initiation are responsible for fungiform papilla initiation. Epithelium-specific expression of an active β-catenin in the Gpr177-deficient tongue leads to fungiform papillae generation, suggesting that an intra-epithelial response to Wnts is required for placode initiation. Together, these results suggest that Gpr177 controls epithelial initiation of the fungiform placode through signaling via epithelial Wnt ligands.

  16. Wnts enhance neurotrophin-induced neuronal differentiation in adult bone-marrow-derived mesenchymal stem cells via canonical and noncanonical signaling pathways.

    Directory of Open Access Journals (Sweden)

    Hung-Li Tsai

    Full Text Available Wnts were previously shown to regulate the neurogenesis of neural stem or progenitor cells. Here, we explored the underlying molecular mechanisms through which Wnt signaling regulates neurotrophins (NTs in the NT-induced neuronal differentiation of human mesenchymal stem cells (hMSCs. NTs can increase the expression of Wnt1 and Wnt7a in hMSCs. However, only Wnt7a enables the expression of synapsin-1, a synaptic marker in mature neurons, to be induced and triggers the formation of cholinergic and dopaminergic neurons. Human recombinant (hrWnt7a and general neuron makers were positively correlated in a dose- and time-dependent manner. In addition, the expression of synaptic markers and neurites was induced by Wnt7a and lithium, a glycogen synthase kinase-3β inhibitor, in the NT-induced hMSCs via the canonical/β-catenin pathway, but was inhibited by Wnt inhibitors and frizzled-5 (Frz5 blocking antibodies. In addition, hrWnt7a triggered the formation of cholinergic and dopaminergic neurons via the non-canonical/c-jun N-terminal kinase (JNK pathway, and the formation of these neurons was inhibited by a JNK inhibitor and Frz9 blocking antibodies. In conclusion, hrWnt7a enhances the synthesis of synapse and facilitates neuronal differentiation in hMSCS through various Frz receptors. These mechanisms may be employed widely in the transdifferentiation of other adult stem cells.

  17. Distinct Patterns of Wnt3a and Wnt5a Signaling Pathway in the Lung from Rats with Endotoxic Shock.

    Directory of Open Access Journals (Sweden)

    Hiong-Ping Hii

    Full Text Available Septic shock is a syndrome with severe hypotension and multiple organ dysfunction caused by an imbalance between pro-inflammatory and anti-inflammatory response. The most common risk factor of acute lung injury is severe sepsis. Patients with sepsis-related acute respiratory distress syndrome have higher mortality. Recent studies reveal regulatory roles of Wnt3a and Wnt5a signaling in inflammatory processes. Wnt3a signaling has been implicated in anti-inflammatory effects, whereas Wnt5a signaling has been postulated to have pro-inflammatory properties. However, the balance between Wnt3a and Wnt5a signaling pathway in the lung of rats with endotoxic shock has not been determined. Thus, we investigated the major components of Wnt3a and Wnt5a signaling pathway in the lung of endotoxemic rats. Male Wistar rats were intravenously infused with saline or lipopolysaccharide (LPS, 10 mg/kg. The changes of hemodynamics, biochemical variables, and arterial blood gas were examined during the experimental period. At 6 h after saline or LPS, animals were sacrificed, and lungs were obtained for analyzing superoxide production, water accumulation, histologic assessment, and protein expressions of Wnt3a and Wnt5a signaling pathway. Animals that received LPS showed circulatory failure, multiple organ dysfunction, metabolic acidosis, hyperventilation, lung edema, and high mortality. The lung from rats with endotoxic shock exhibited significant decreases in the levels of Wnt3a, Fzd1, Dsh1, phosphorylated GSK-3β at Ser9, and β-catenin. In contrast, the expressions of Wnt5a, Fzd5, and CaMKII were up-regulated in the lung of endotoxemic rats. These findings indicate the major components of Wnt3a and Wnt5a signaling in the lung are disturbed under endotoxic insult.

  18. Berberine acts as a natural inhibitor of Wnt/β-catenin signaling--identification of more active 13-arylalkyl derivatives.

    Science.gov (United States)

    Albring, Kai Frederik; Weidemüller, Julia; Mittag, Sonnhild; Weiske, Jörg; Friedrich, Karlheinz; Geroni, M Cristina; Lombardi, Paolo; Huber, Otmar

    2013-01-01

    Aberrant activation of the canonical Wnt/β-catenin signaling pathway has been reported for numerous tumors of different origins. In most cases, mutations in components of the Wnt signaling pathway or in β-catenin itself were detected which ultimately induce a genetic program that promotes cell proliferation and attenuates apoptosis. Thus, targeting of Wnt/β-catenin signaling is of specific therapeutic interest. Herein, we investigated the plant-derived isoquinoline alkaloid berberine, which has been reported to have anticancer activity, and synthetic 13-arylalkyl derivatives thereof for their effects on Wnt/β-catenin signaling. Berberine did not show major effects on viability of HEK-293 embryonic kidney and HCT116 colon carcinoma cells and was not toxic in concentrations up to 20 µM. Berberine inhibited β-catenin transcriptional activity and attenuated anchorage-independent growth. As a result of berberine treatment, cellular levels of active β-catenin were reduced concomitant with an increase in the expression of E-cadherin. However, in unstimulated cells, the effects on β-catenin levels were low. A screen of synthetic 13-arylalkyl berberine derivatives identified compounds exhibiting activities superior to those of the naturally occurring parent substance with more than 100-fold lower EC50 values for Wnt-repression. Thus, berberine and its synthetic derivatives represent potential therapeutic agents to inhibit Wnt/β-catenin signaling in tumorigenesis.

  19. ALFY-Controlled DVL3 Autophagy Regulates Wnt Signaling, Determining Human Brain Size.

    Science.gov (United States)

    Kadir, Rotem; Harel, Tamar; Markus, Barak; Perez, Yonatan; Bakhrat, Anna; Cohen, Idan; Volodarsky, Michael; Feintsein-Linial, Miora; Chervinski, Elana; Zlotogora, Joel; Sivan, Sara; Birnbaum, Ramon Y; Abdu, Uri; Shalev, Stavit; Birk, Ohad S

    2016-03-01

    Primary microcephaly is a congenital neurodevelopmental disorder of reduced head circumference and brain volume, with fewer neurons in the cortex of the developing brain due to premature transition between symmetrical and asymmetrical cellular division of the neuronal stem cell layer during neurogenesis. We now show through linkage analysis and whole exome sequencing, that a dominant mutation in ALFY, encoding an autophagy scaffold protein, causes human primary microcephaly. We demonstrate the dominant effect of the mutation in drosophila: transgenic flies harboring the human mutant allele display small brain volume, recapitulating the disease phenotype. Moreover, eye-specific expression of human mutant ALFY causes rough eye phenotype. In molecular terms, we demonstrate that normally ALFY attenuates the canonical Wnt signaling pathway via autophagy-dependent removal specifically of aggregates of DVL3 and not of Dvl1 or Dvl2. Thus, autophagic attenuation of Wnt signaling through removal of Dvl3 aggregates by ALFY acts in determining human brain size.

  20. ALFY-Controlled DVL3 Autophagy Regulates Wnt Signaling, Determining Human Brain Size.

    Directory of Open Access Journals (Sweden)

    Rotem Kadir

    2016-03-01

    Full Text Available Primary microcephaly is a congenital neurodevelopmental disorder of reduced head circumference and brain volume, with fewer neurons in the cortex of the developing brain due to premature transition between symmetrical and asymmetrical cellular division of the neuronal stem cell layer during neurogenesis. We now show through linkage analysis and whole exome sequencing, that a dominant mutation in ALFY, encoding an autophagy scaffold protein, causes human primary microcephaly. We demonstrate the dominant effect of the mutation in drosophila: transgenic flies harboring the human mutant allele display small brain volume, recapitulating the disease phenotype. Moreover, eye-specific expression of human mutant ALFY causes rough eye phenotype. In molecular terms, we demonstrate that normally ALFY attenuates the canonical Wnt signaling pathway via autophagy-dependent removal specifically of aggregates of DVL3 and not of Dvl1 or Dvl2. Thus, autophagic attenuation of Wnt signaling through removal of Dvl3 aggregates by ALFY acts in determining human brain size.

  1. WNT signaling regulates self-renewal and differentiation of prostate cancer cells with stem cell characteristics

    Institute of Scientific and Technical Information of China (English)

    Isabelle Bisson; David M Prowse

    2009-01-01

    Prostate cancer cells with stem cell characteristics were identified in human prostate cancer cell lines by their abil-ity to form from single cells self-renewing prostaspheres in non-adherent cultures. Prostaspheres exhibited heteroge-neous expression of proliferation, differentiation and stem cell-associated makers CD44, ABCG2 and CD133. Treat-ment with WNT inhibitors reduced both prostasphere size and self-renewal, In contrast, addition of Wnt3a caused increased prostasphere size and self-renewal, which was associated with a significant increase in nuclear β-catenin, keratin 18, CD133 and CD44 expression. As a high proportion of LNCaP and C4-2B cancer cells express androgen receptor we determined the effect of the androgen receptor antagonist bicalutamide. Androgen receptor inhibition reduced prostasphere size and expression of PSA, but did not inhibit prostasphere formation. These effects are con-sistent with the androgen-independent self-renewal of cells with stem cell characteristics and the androgen-dependent proliferation of transit amplifying cells. As the canonical WNT signaling effector β-catenin can also associate with the androgen receptor, we propose a model for tumour propagation involving a balance between WNT and androgen re-ceptor activity. That would affect the self-renewal of a cancer cell with stem cell characteristics and drive transit am-plifying cell proliferation and differentiation. In conclusion, we provide evidence that WNT activity regulates the self-renewal of prostate cancer cells with stem cell characteristics independently of androgen receptor activity. Inhibition of WNT signaling therefore has the potential to reduce the self-renewal of prostate cancer cells with stem cell charac-teristics and improve the therapeutic outcome.

  2. Inhibitors of endocytosis prevent Wnt/Wingless signalling by reducing the level of basal β-catenin/Armadillo.

    Science.gov (United States)

    Gagliardi, Maria; Hernandez, Ana; McGough, Ian J; Vincent, Jean-Paul

    2014-11-15

    A key step in the canonical Wnt signalling pathway is the inhibition of GSK3β, which results in the accumulation of nuclear β-catenin (also known as CTNNB1), and hence regulation of target genes. Evidence suggests that endocytosis is required for signalling, yet its role and the molecular understanding remains unclear. A recent and controversial model suggests that endocytosis contributes to Wnt signalling by causing the sequestration of the ligand-receptor complex, including LRP6 and GSK3 to multivesicular bodies (MVBs), thus preventing GSK3β from accessing β-catenin. Here, we use specific inhibitors (Dynasore and Dyngo-4a) to confirm the essential role of endocytosis in Wnt/Wingless signalling in human and Drosophila cells. However, we find no evidence that, in Drosophila cells or wing imaginal discs, LRP6/Arrow traffics to MVBs or that MVBs are required for Wnt/Wingless signalling. Moreover, we show that activation of signalling through chemical blockade of GSK3β is prevented by endocytosis inhibitors, suggesting that endocytosis impacts on Wnt/Wingless signalling downstream of the ligand-receptor complex. We propose that, through an unknown mechanism, endocytosis boosts the resting pool of β-catenin upon which GSK3β normally acts.

  3. Wnt5a and Wnt11 are essential for second heart field progenitor development

    Science.gov (United States)

    Cohen, Ethan David; Miller, Mayumi F.; Wang, Zichao; Moon, Randall T.; Morrisey, Edward E.

    2012-01-01

    Wnt/β-catenin has a biphasic effect on cardiogenesis, promoting the induction of cardiac progenitors but later inhibiting their differentiation. Second heart field progenitors and expression of the second heart field transcription factor Islet1 are inhibited by the loss of β-catenin, indicating that Wnt/β-catenin signaling is necessary for second heart field development. However, expressing a constitutively active β-catenin with Islet1-Cre also inhibits endogenous Islet1 expression, reflecting the inhibitory effect of prolonged Wnt/β-catenin signaling on second heart field development. We show that two non-canonical Wnt ligands, Wnt5a and Wnt11, are co-required to regulate second heart field development in mice. Loss of Wnt5a and Wnt11 leads to a dramatic loss of second heart field progenitors in the developing heart. Importantly, this loss of Wnt5a and Wnt11 is accompanied by an increase in Wnt/β-catenin signaling, and ectopic Wnt5a/Wnt11 inhibits β-catenin signaling and promotes cardiac progenitor development in differentiating embryonic stem cells. These data show that Wnt5a and Wnt11 are essential regulators of the response of second heart field progenitors to Wnt/β-catenin signaling and that they act by restraining Wnt/β-catenin signaling during cardiac development. PMID:22569553

  4. Wnt signaling through T-cell factor phosphorylation

    Institute of Scientific and Technical Information of China (English)

    Sergei Y Sokol

    2011-01-01

    Embryonic signaling pathways often lead to a switch from default repression to transcriptional activation of target genes. A major consequence of Wnt signaling is stabilization of p-catenin, which associates with T-cell factors (TCFs) and 'converts' them from repressors into transcriptional activators. The molecular mechanisms responsible for this conversion remain poorly understood. Several studies have reported on the regulation of TCF by phosphorylation,yet its physiological significance has been unclear: in some cases it appears to promote target gene activation, in oth-ers Wnt-dependent transcription is inhibited. This review focuses on recent progress in the understanding of context-dependent post-translational regulation of TCF function by Wnt signaling.

  5. Further evidence of the involvement of the Wnt signaling pathway in Dupuytren's disease

    NARCIS (Netherlands)

    ten Dam, Evert-Jan P. M.; van Beuge, Marike M.; Bank, Ruud A.; Werker, Paul M. N.

    2016-01-01

    Genetic background plays an important role in the development of Dupuytren's disease. A genome-wide association study (GWAS) showed that nine loci are associated with the disease, six of which contain genes that are involved in Wnt signaling (WNT2, WNT4, WNT7B, RSPO2, SFRP4, SULF1). To obtain insigh

  6. Pentoxifylline Inhibits WNT Signalling in β-Cateninhigh Patient-Derived Melanoma Cell Populations

    Science.gov (United States)

    Talar, Beata; Gajos-Michniewicz, Anna; Talar, Marcin; Chouaib, Salem; Czyz, Malgorzata

    2016-01-01

    Background The heterogeneity of melanoma needs to be addressed and combination therapies seem to be necessary to overcome intrinsic and acquired resistance to newly developed immunotherapies and targeted therapies. Although the role of WNT/β-catenin pathway in melanoma was early demonstrated, its contribution to the lack of the melanoma patient response to treatment was only recently recognized. Using patient-derived melanoma cell populations, we investigated the influence of pentoxifylline on melanoma cells with either high or low expression of β-catenin. Findings Our results indicate that pentoxifylline inhibits the activity of the canonical WNT pathway in melanoma cell populations with high basal activity of this signalling. This is supported by lowered overall activity of transcription factors TCF/LEF and reduced nuclear localisation of active β-catenin. Moreover, treatment of β-cateninhigh melanoma cell populations with pentoxifylline induces downregulation of genes that are targets of the WNT/β-catenin pathway including connective tissue growth factor (CTGF) and microphthalmia-associated transcription factor (MITF-M), a melanocyte- and melanoma cell-specific regulator. Conclusions These results suggest that pentoxifylline, a drug approved by the FDA in the treatment of peripheral arterial disease, might be tested in a subset of melanoma patients with elevated activity of β-catenin. This pharmaceutical might be tested as an adjuvant drug in combination therapies when the response to immunotherapy is prevented by high activity of the WNT/β-catenin pathway. PMID:27351373

  7. Pentoxifylline Inhibits WNT Signalling in β-Cateninhigh Patient-Derived Melanoma Cell Populations.

    Directory of Open Access Journals (Sweden)

    Beata Talar

    Full Text Available The heterogeneity of melanoma needs to be addressed and combination therapies seem to be necessary to overcome intrinsic and acquired resistance to newly developed immunotherapies and targeted therapies. Although the role of WNT/β-catenin pathway in melanoma was early demonstrated, its contribution to the lack of the melanoma patient response to treatment was only recently recognized. Using patient-derived melanoma cell populations, we investigated the influence of pentoxifylline on melanoma cells with either high or low expression of β-catenin.Our results indicate that pentoxifylline inhibits the activity of the canonical WNT pathway in melanoma cell populations with high basal activity of this signalling. This is supported by lowered overall activity of transcription factors TCF/LEF and reduced nuclear localisation of active β-catenin. Moreover, treatment of β-cateninhigh melanoma cell populations with pentoxifylline induces downregulation of genes that are targets of the WNT/β-catenin pathway including connective tissue growth factor (CTGF and microphthalmia-associated transcription factor (MITF-M, a melanocyte- and melanoma cell-specific regulator.These results suggest that pentoxifylline, a drug approved by the FDA in the treatment of peripheral arterial disease, might be tested in a subset of melanoma patients with elevated activity of β-catenin. This pharmaceutical might be tested as an adjuvant drug in combination therapies when the response to immunotherapy is prevented by high activity of the WNT/β-catenin pathway.

  8. Location-specific effect of microbiota and MyD88-dependent signaling on Wnt/β-catenin pathway and intestinal stem cells.

    Science.gov (United States)

    Moossavi, Shirin

    2014-01-01

    Intestinal homeostasis depends on the proper activity of the intestinal stem cells (ISCs) and an appropriate host response to the normal resident microbiota. The question on the effect of microbiota on ISCs behavior has not been addressed yet. Canonical Wnt pathway and ISC gene expression signature was compared in germfree vs. conventional and MyD88(-/-) vs. Myd88(+/+) mice based on publicly available gene expression data sets. Microbiota and MyD88-dependent signaling have distinct effects on the Wnt pathway and ISC at gene expression level. In addition, the effect of microbiota and MyD88-dependent signaling on Wnt pathway and ISCs show regional variation. The net effect of microbiota on Wnt pathway and ISCs cannot be inferred from the available data. Nonetheless, the data are suggestive of a potential regulatory mechanism of the Wnt pathway by the microbiota and plausibly by any alteration in the microbiota composition.

  9. Excessive Wnt/beta-catenin signaling promotes midbrain floor plate neurogenesis, but results in vacillating dopamine progenitors.

    Science.gov (United States)

    Nouri, Navid; Patel, Meera J; Joksimovic, Milan; Poulin, Jean-Francois; Anderegg, Angela; Taketo, M Mark; Ma, Yong-Chao; Awatramani, Rajeshwar

    2015-09-01

    The floor plate (FP), a ventral midline structure of the developing neural tube, has differential neurogenic capabilities along the anterior-posterior axis. The midbrain FP, unlike the hindbrain and spinal cord floor plate, is highly neurogenic and produces midbrain dopaminergic (mDA) neurons. Canonical Wnt/beta-catenin signaling, at least in part, is thought to account for the difference in neurogenic capability. Removal of beta-catenin results in mDA progenitor specification defects as well as a profound reduction of neurogenesis. To examine the effects of excessive Wnt/beta-catenin signaling on mDA specification and neurogenesis, we have analyzed a model wherein beta-catenin is conditionally stabilized in the Shh+domain. Here, we show that the Foxa2+/Lmx1a+ domain is extended rostrally in mutant embryos, suggesting that canonical Wnt/beta-catenin signaling can drive FP expansion along the rostrocaudal axis. Although excess canonical Wnt/beta-catenin signaling generally promotes neurogenesis at midbrain levels, less tyrosine hydroxylase (Th)+, mDA neurons are generated, particularly impacting the Substantia Nigra pars compacta. This is likely because of improper progenitor specification. Excess canonical Wnt/beta-catenin signaling causes downregulation of net Lmx1b, Shh and Foxa2 levels in mDA progenitors. Moreover, these progenitors assume a mixed identity to that of Lmx1a+/Lmx1b+/Nkx6-1+/Neurog1+ progenitors. We also show by lineage tracing analysis that normally, Neurog1+ progenitors predominantly give rise to Pou4f1+ neurons, but not Th+ neurons. Accordingly, in the mutant embryos, Neurog1+ progenitors at the midline generate ectopic Pou4f1+ neurons at the expense of Th+ mDA neurons. Our study suggests that an optimal dose of Wnt/beta-catenin signaling is critical for proper establishment of the mDA progenitor character. Our findings will impact embryonic stem cell protocols that utilize Wnt pathway reagents to derive mDA neuron models and therapeutics for

  10. Genomic DISC1 Disruption in hiPSCs Alters Wnt Signaling and Neural Cell Fate

    Directory of Open Access Journals (Sweden)

    Priya Srikanth

    2015-09-01

    Full Text Available Genetic and clinical association studies have identified disrupted in schizophrenia 1 (DISC1 as a candidate risk gene for major mental illness. DISC1 is interrupted by a balanced chr(1;11 translocation in a Scottish family in which the translocation predisposes to psychiatric disorders. We investigate the consequences of DISC1 interruption in human neural cells using TALENs or CRISPR-Cas9 to target the DISC1 locus. We show that disruption of DISC1 near the site of the translocation results in decreased DISC1 protein levels because of nonsense-mediated decay of long splice variants. This results in an increased level of canonical Wnt signaling in neural progenitor cells and altered expression of fate markers such as Foxg1 and Tbr2. These gene expression changes are rescued by antagonizing Wnt signaling in a critical developmental window, supporting the hypothesis that DISC1-dependent suppression of basal Wnt signaling influences the distribution of cell types generated during cortical development.

  11. Expression of osterix Is Regulated by FGF and Wnt/β-Catenin Signalling during Osteoblast Differentiation.

    Directory of Open Access Journals (Sweden)

    Katharina Felber

    Full Text Available Osteoblast differentiation from mesenchymal cells is regulated by multiple signalling pathways. Here we have analysed the roles of Fibroblast Growth Factor (FGF and canonical Wingless-type MMTV integration site (Wnt/β-Catenin signalling pathways on zebrafish osteogenesis. We have used transgenic and chemical interference approaches to manipulate these pathways and have found that both pathways are required for osteoblast differentiation in vivo. Our analysis of bone markers suggests that these pathways act at the same stage of differentiation to initiate expression of the osteoblast master regulatory gene osterix (osx. We use two independent approaches that suggest that osx is a direct target of these pathways. Firstly, we manipulate signalling and show that osx gene expression responds with similar kinetics to that of known transcriptional targets of the FGF and Wnt pathways. Secondly, we have performed ChIP with transcription factors for both pathways and our data suggest that a genomic region in the first intron of osx mediates transcriptional activation. Based upon these data, we propose that FGF and Wnt/β-Catenin pathways act in part by directing transcription of osx to promote osteoblast differentiation at sites of bone formation.

  12. Determine the Role of Canonical Wnt Signaling in Ovarian Tumorigenesis

    Science.gov (United States)

    2015-12-01

    PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Betty Diamond 5d. PROJECT NUMBER Rugang Zhang, Ph.D. 5e. TASK NUMBER E-Mail: rzhang@wistar.org 5f. WORK UNIT...43 0 6 D ec em be r 20 15 9. Knutson SK, Warholic NM, Wigle TJ, Klaus CR, Allain CJ, Raimondi A, Porter Scott M, Chesworth R, Moyer MP, Copeland

  13. WNT4 acts downstream of BMP2 and functions via β-catenin signaling pathway to regulate human endometrial stromal cell differentiation.

    Science.gov (United States)

    Li, Quanxi; Kannan, Athilakshmi; Das, Amrita; Demayo, Franco J; Hornsby, Peter J; Young, Steven L; Taylor, Robert N; Bagchi, Milan K; Bagchi, Indrani C

    2013-01-01

    Differentiation of endometrial stromal cells into decidual cells is a prerequisite for successful embryo implantation. Our previous studies in the mouse have shown that bone morphogenetic protein 2 (BMP2), a morphogen belonging to the TGFβ superfamily, is essential for this differentiation process. BMP2 is markedly induced in human primary endometrial stromal cells (HESCs) as they undergo differentiation in response to steroid hormones and cAMP. The present study was undertaken to identify the BMP2-mediated molecular pathways in primary cultures of HESCs during decidualization. Using gene expression profiling, we identified wingless-related murine mammary tumor virus integration site 4 (WNT4) as a target of BMP2 regulation during decidualization. Attenuation of WNT4 expression in HESCs by small interfering RNA administration greatly reduced BMP2-induced stromal differentiation. Additionally, adenovirus-mediated overexpression of WNT4 in HESCs markedly advanced the differentiation program, indicating that it is a key regulator of decidualization. The stimulatory effect of WNT4 was accompanied by the accumulation of active β-catenin in the nuclei of decidualizing stromal cells, indicating the involvement of the canonical WNT signaling pathway. Functional inhibition of WNT4/β-catenin pathway by Dickkopf-1, an inhibitor of the canonical WNT signaling, or small interfering RNA-mediated silencing of β-catenin expression, greatly reduced the BMP2- and WNT4-induced decidualization. Gene expression profiling revealed that Forkhead box protein O1, a forkhead family transcription factor and previously reported regulator of HESC differentiation, is a common downstream mediator of both BMP2 and WNT4 signaling. Taken together, these studies uncovered a linear pathway involving BMP2, WNT4/β-catenin, and Forkhead box protein O1 that operates in human endometrium to critically control decidualization.

  14. Does murine spermatogenesis require WNT signalling? A lesson from Gpr177 conditional knockout mouse models

    OpenAIRE

    Chen, Su-Ren; Tang, J-X; Cheng, J-M; Hao, X-X; Wang, Y-Q; Wang, X-X; Liu, Y-X

    2016-01-01

    Wingless-related MMTV integration site (WNT) proteins and several other components of the WNT signalling pathway are expressed in the murine testes. However, mice mutant for WNT signalling effector β-catenin using different Cre drivers have phenotypes that are inconsistent with each other. The complexity and overlapping expression of WNT signalling cascades have prevented researchers from dissecting their function in spermatogenesis. Depletion of the Gpr177 gene (the mouse orthologue of Droso...

  15. Effects of fruit ellagitannin extracts, ellagic acid, and their colonic metabolite, urolithin A, on Wnt signaling.

    Science.gov (United States)

    Sharma, Meenakshi; Li, Liya; Celver, Jeremy; Killian, Caroline; Kovoor, Abraham; Seeram, Navindra P

    2010-04-14

    Recent data suggest that ellagitannins (ETs), a class of hydrolyzable tannins found in some fruits and nuts, may have beneficial effects against colon cancer. In the stomach and gut, ETs hydrolyze to release ellagic acid (EA) and are converted by gut microbiota to urolithin A (UA; 3,8-dihydroxy-6H-dibenzopyran-6-one) type metabolites, which may persist in the colon through enterohepatic circulation. However, little is known about the mechanisms of action of either the native compounds or their metabolites on colon carcinogenesis. Components of Wnt signaling pathways are known to play a pivotal role in human colon carcinogenesis, and inappropriate activation of the signaling cascade is observed in 90% of colorectal cancers. This study investigated the effects of UA, EA, and ET-rich fruit extracts on Wnt signaling in a human 293T cell line using a luciferase reporter of canonical Wnt pathway-mediated transcriptional activation. The ET extracts were obtained from strawberry (Fragaria annassa), Jamun berry (Eugenia jambolana), and pomegranate (Punica granatum) fruit and were all standardized to phenolic content (as gallic acid equivalents, GAEs, by the Folin-Ciocalteu method) and to EA content (by high-performance liquid chromatography methods): strawberry = 20.5% GAE, 5.0% EA; Jamun berry = 20.5% GAE, 4.2% EA; pomegranate = 55% GAE, 3.5% EA. The ET extracts (IC(50) = 28.0-30.0 microg/mL), EA (IC(50) = 19.0 microg/mL; 63 microM), and UA (IC(50) = 9.0 microg/mL; 39 microM) inhibited Wnt signaling, suggesting that ET-rich foods have potential against colon carcinogenesis and that urolithins are relevant bioactive constituents in the colon.

  16. Wnt gene loss in flatworms.

    Science.gov (United States)

    Riddiford, Nick; Olson, Peter D

    2011-10-01

    Wnt genes encode secreted glycoproteins that act in cell-cell signalling to regulate a wide array of developmental processes, ranging from cellular differentiation to axial patterning. Discovery that canonical Wnt/β-catenin signalling is responsible for regulating head/tail specification in planarian regeneration has recently highlighted their importance in flatworm (phylum Platyhelminthes) development, but examination of their roles in the complex development of the diverse parasitic groups has yet to be conducted. Here, we characterise Wnt genes in the model tapeworm Hymenolepis microstoma and mine genomic resources of free-living and parasitic species for the presence of Wnts and downstream signalling components. We identify orthologs through a combination of BLAST and phylogenetic analyses, showing that flatworms have a highly reduced and dispersed complement that includes orthologs of only five subfamilies (Wnt1, Wnt2, Wnt4, Wnt5 and Wnt11) and fewer paralogs in parasitic flatworms (5-6) than in planarians (9). All major signalling components are identified, including antagonists and receptors, and key binding domains are intact, indicating that the canonical (Wnt/β-catenin) and non-canonical (planar cell polarity and Wnt/Ca(2+)) pathways are functional. RNA-Seq data show expression of all Hymenolepis Wnts and most downstream components in adults and larvae with the notable exceptions of wnt1, expressed only in adults, and wnt2 expressed only in larvae. The distribution of Wnt subfamilies in animals corroborates the idea that the last common ancestor of the Cnidaria and Bilateria possessed all contemporary Wnts and highlights the extent of gene loss in flatworms.

  17. The Canonical Wnt Pathway Regulates the Metastasis-Promoting Mucin MUC4 in Pancreatic Ductal Adenocarcinoma

    Science.gov (United States)

    Pai, Priya; Rachagani, Satyanarayana; Lakshmanan, Imayavaramban; Macha, Muzafar A; Sheinin, Yuri; Smith, Lynette M.; Ponnusamy, Moorthy P.; Batra, Surinder K.

    2015-01-01

    Aberrant Wnt signaling frequently occurs in pancreatic cancer (PC) and contributes to disease progression/metastases. Likewise, the transmembrane-mucin MUC4 is expressed de novo in early pancreatic intraepithelial neoplasia (PanINs) and incrementally increases with PC progression, contributing to metastasis. To determine the mechanism of MUC4 upregulation in PC, we examined factors deregulated in early PC progression, such as Wnt/β-catenin signaling. MUC4 promoter analysis revealed the presence of three putative TCF/LEF-binding sites, leading us to hypothesize that MUC4 can be regulated by β-catenin. Immunohistochemical (IHC) analysis of rapid autopsy PC tissues showed a correlation between MUC4 and cytosolic/nuclear β-catenin expression. Knock down (KD) of β-catenin in CD18/HPAF and T3M4 cell lines resulted in decreased MUC4 transcript and protein. Three MUC4 promoter luciferase constructs, p3778, p3000, and p2700, were generated. The construct p3778, encompassing the entire MUC4 promoter, elicited increased luciferase activity in the presence of stabilized β-catenin. Mutation of the TCF/LEF site closest to the transcription start site (i.e., −2629/−2612) and furthest from the start site (i.e., −3425/−3408) reduced MUC4 promoter luciferase activity. Transfection with dominant negative TCF4 decreased MUC4 transcript and protein levels. Chromatin immunoprecipitation confirmed enrichment of β-catenin on −2629/−2612 and −3425/−3408 of the MUC4 promoter in CD18/HPAF. Functionally, CD18/HPAF and T3M4 β-catenin KD cells showed decreased migration and decreased Vimentin, N-cadherin, and pERK1/2 expression. Tumorigenicity studies in athymic nude mice showed CD18/HPAF β-catenin KD cells significantly reduced primary tumor sizes and metastases compared to scrambled control cells. We show for the first time that β-catenin directly governs MUC4 in PC. PMID:26526617

  18. PR72, a novel regulator of Wnt signaling required for Naked cuticle function

    NARCIS (Netherlands)

    Creyghton, M.P.; Roël, G.; Eichhorn, P.J.A.; Hijmans, E.M.; Maurer, I.; Destrée, O.; Bernards, R.A.

    2005-01-01

    The Wnt signaling cascade is a central regulator of cell fate determination during embryonic development, whose deregulation contributes to oncogenesis. Naked cuticle is the first Wnt-induced antagonist found in this pathway, establishing a negative-feedback loop that limits the Wnt signal required

  19. Epidermal Wnt controls hair follicle induction by orchestrating dynamic signaling crosstalk between the epidermis and dermis.

    Science.gov (United States)

    Fu, Jiang; Hsu, Wei

    2013-04-01

    A signal first arising in the dermis to initiate the development of hair follicles has been described for many decades. Wnt is the earliest signal known to be intimately involved in hair follicle induction. However, it is not clear whether the inductive signal of Wnt arises intradermally or intraepidermally. Whether Wnt acts as the first dermal signal to initiate hair follicle development also remains unclear. Here we report that Wnt production mediated by Gpr177, the mouse Wls ortholog, is essential for hair follicle induction. Gpr177, encoding a multipass transmembrane protein, regulates Wnt sorting and secretion. Cell type-specific abrogation of the signal reveals that only epidermal, but not dermal, production of Wnt is required. An intraepidermal Wnt signal is necessary and sufficient for hair follicle initiation. However, the subsequent development depends on reciprocal signaling crosstalk of epidermal and dermal cells. Wnt signals within the epidermis and dermis and crossing between the epidermis and dermis have distinct roles and specific functions in skin development. This study not only defines the cell type responsible for Wnt production, but also reveals a highly dynamic regulation of Wnt signaling at different steps of hair follicle morphogenesis. Our findings uncover a mechanism underlying hair follicle development orchestrated by the Wnt pathway.

  20. Purified Wnt-5a increases differentiation of midbrain dopaminergic cells and dishevelled phosphorylation.

    Science.gov (United States)

    Schulte, Gunnar; Bryja, Vítezslav; Rawal, Nina; Castelo-Branco, Goncalo; Sousa, Kyle M; Arenas, Ernest

    2005-03-01

    The Wnt family of lipoproteins regulates several aspects of the development of the nervous system. Recently, we reported that Wnt-3a enhances the proliferation of midbrain dopaminergic precursors and that Wnt-5a promotes their differentiation into dopaminergic neurones. Here we report the purification of hemagglutinin-tagged Wnt-5a using a three-step purification method similar to that previously described for Wnt-3a. Haemagglutinin-tagged Wnt-5a was biologically active and induced the differentiation of immature primary midbrain precursors into tyrosine hydroxylase-positive dopaminergic neurones. Using a substantia nigra-derived dopaminergic cell line (SN4741), we found that Wnt-5a, unlike Wnt-3a, did not promote beta-catenin phosphorylation or stabilization. However, both Wnt-5a and Wnt-3a activated dishevelled, as assessed by a phosphorylation-dependent mobility shift. Moreover, the activity of Wnt-5a on dishevelled was blocked by pre-treatment with acyl protein thioesterase-1, indicating that palmitoylation of Wnt-5a is necessary for its function. Thus, our results suggest that Wnt-3a and Wnt-5a, respectively, activate canonical and non-canonical Wnt signalling pathways in ventral midbrain dopaminergic cells. Furthermore, we identify dishevelled as a key player in transducing both Wnt canonical and non-canonical signals in dopaminergic cells.

  1. Evidence of non-canonical NOTCH signaling

    DEFF Research Database (Denmark)

    Traustadóttir, Gunnhildur Ásta; Jensen, Charlotte H; Thomassen, Mads

    2016-01-01

    Dlk1(+/+) and Dlk1(-/-) mouse tissues at E16.5, we demonstrated that several NOTCH signaling pathways indeed are affected by DLK1 during tissue development, and this was supported by a lower activation of NOTCH1 protein in Dlk1(+/+) embryos. Likewise, but using a distinct Dlk1-manipulated (si...

  2. Skeletal metastasis: treatments, mouse models,and the Wnt signaling

    Institute of Scientific and Technical Information of China (English)

    Kenneth C.Valkenburg; Matthew R.Steensma; Bart O.Williams; Zhendong Zhong

    2013-01-01

    Skeletal metastases result in significant morbidity and mortality.This is particularly true of cancers with a strong predilection for the bone,such as breast,prostate,and lung cancers.There is currently no reliable cure for skeletal metastasis,and palliative therapy options are limited.The Wnt signaling pathway has been found to play an integral role in the process of skeletal metastasis and may be an important clinical target.Several experimental models of skeletal metastasis have been used to find new biomarkers and test new treatments.In this review,we discuss pathologic process of bone metastasis,the roles of the Wnt signaling,and the available experimental models and treatments.

  3. Wnt signaling and colon tumorigenesis - A view from the periphery

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, Antony W., E-mail: burgess@ludwig.edu.au [Parkville Branch, Ludwig Institute for Cancer Research, Melbourne, 3050 (Australia); Faux, Maree C. [Parkville Branch, Ludwig Institute for Cancer Research, Melbourne, 3050 (Australia); Layton, Meredith J. [Department of Biochemistry and Molecular Biology, Monash University, Melbourne, 3800 (Australia); Ramsay, Robert G. [Peter MacCallum Cancer Centre, Melbourne, 3002 (Australia); Pathology Department, the University of Melbourne, Parkville, 3050 (Australia)

    2011-11-15

    In this brief overview we discuss the association between Wnt signaling and colon cell biology and tumorigenesis. Our current understanding of the role of Apc in the {beta}-catenin destruction complex is compared with potential roles for Apc in cell adhesion and migration. The requirement for phosphorylation in the proteasomal-mediated degradation of {beta}-catenin is contrasted with roles for phospho-{beta}-catenin in the activation of transcription, cell adhesion and migration. The synergy between Myb and {beta}-catenin regulation of transcription in crypt stem cells during Wnt signaling is discussed. Finally, potential effects of growth factor regulatory systems, Apc or truncated-Apc on crypt morphogenesis, stem cell localization and crypt fission are considered.

  4. RHOA inactivation enhances Wnt signaling and promotes colorectal cancer

    Science.gov (United States)

    Rodrigues, Paulo; Macaya, Irati; Bazzocco, Sarah; Mazzolini, Rocco; Andretta, Elena; Dopeso, Higinio; Mateo-Lozano, Silvia; Bilić, Josipa; Cartón-García, Fernando; Nieto, Rocio; Suárez-López, Lucia; Afonso, Elsa; Landolfi, Stefania; Hernandez-Losa, Javier; Kobayashi, Kazuto; Cajal, Santiago Ramón y; Tabernero, Josep; Tebbutt, Niall C.; Mariadason, John M.; Schwartz, Simo; Arango, Diego

    2014-01-01

    Activation of the small GTPase RHOA has strong oncogenic effects in many tumor types, although its role in colorectal cancer remains unclear. Here we show that RHOA inactivation contributes to colorectal cancer progression/metastasis, largely through the activation of Wnt/β-catenin signaling. RhoA inactivation in the murine intestine accelerates the tumorigenic process and in human colon cancer cells leads to the redistribution of β-catenin from the membrane to the nucleus and enhanced Wnt/β-catenin signaling, resulting in increased proliferation, invasion and de-differentiation. In mice, RHOA inactivation contributes to colon cancer metastasis and reduced RHOA levels were observed at metastatic sites compared to primary human colon tumors. Therefore, we have identified a new mechanism of activation of Wnt/β-catenin signaling and characterized the role of RHOA as a novel tumor suppressor in colorectal cancer. These results constitute a shift from the current paradigm and demonstrate that RHO GTPases can suppress tumor progression and metastasis. PMID:25413277

  5. Wnt-Frizzled/planar cell polarity signaling: cellular orientation by facing the wind (Wnt).

    Science.gov (United States)

    Yang, Yingzi; Mlodzik, Marek

    2015-01-01

    The establishment of planar cell polarity (PCP) in epithelial and mesenchymal cells is a critical, evolutionarily conserved process during development and organogenesis. Analyses in Drosophila and several vertebrate model organisms have contributed a wealth of information on the regulation of PCP. A key conserved pathway regulating PCP, the so-called core Wnt-Frizzled PCP (Fz/PCP) signaling pathway, was initially identified through genetic studies of Drosophila. PCP studies in vertebrates, most notably mouse and zebrafish, have identified novel factors in PCP signaling and have also defined cellular features requiring PCP signaling input. These studies have shifted focus to the role of Van Gogh (Vang)/Vangl genes in this molecular system. This review focuses on new insights into the core Fz/Vangl/PCP pathway and recent advances in Drosophila and vertebrate PCP studies. We attempt to integrate these within the existing core Fz/Vangl/PCP signaling framework.

  6. Regulation of lubricin/superficial zone protein by Wnt signalling in bovine synoviocytes.

    Science.gov (United States)

    Inui, Atsuyuki; Iwakura, Takashi; Hari Reddi, A

    2016-02-01

    Lubricin, homologous to superficial zone protein (SZP), functions as a boundary lubricant in articular cartilage and plays an essential role in the maintenance of joint function and homeostasis. Wnt signalling plays a key role in joint development, including synovial joint formation, and several Wnt proteins are expressed in the synovium and articular cartilage in arthritis. The aim of this study was to determine the role of Wnt signalling on SZP accumulation in synoviocytes. Isolated synoviocytes from bovine knee joints were cultured with Wnt proteins (Wnt-3a and Wnt-5a) and antagonists or agonists of the Wnt-β-catenin pathway or Wnt-Ca(2+) pathway in serum-free chemically defined medium. SZP accumulation in the culture medium was determined by enzyme-linked immunosorbent assay. Wnt-3a suppressed SZP accumulation via a Wnt-β-catenin-dependent pathway. In contrast, Wnt-5a stimulated SZP accumulation via a β-catenin independent pathway. The present investigation provides novel insights into the role of the Wnt signalling pathways in SZP accumulation in synoviocytes and their roles in the homeostasis of normal joints.

  7. Immunoexpression of Wnt/β-catenin signaling pathway proteins in ameloblastoma and calcifying cystic odontogenic tumor

    Science.gov (United States)

    Dutra, Sabrina-Nogueira; Pires, Fábio-Ramôa; Armada, Luciana

    2017-01-01

    Background Wnt/β-catenin signaling pathway is essential for the beginning of odontogenesis and may be involved in the development and progression of some odontogenic tumors. Thus, the aim of this study was to comparatively evaluate the immunohistochemical expression of Wnt/β-catenin signaling pathway proteins in a series of AME and CCOT. Material and Methods Immunohistochemical reactions were performed using antibodies against Wnt1, Wnt5a and β-catenin in 17 cases of solid AME and 6 cases of CCOT. Results In the AME group, Wnt1 and Wnt5a were identified in the epithelium in most of the cases, and β-catenin was mainly identified in the cytoplasm of the tumoral cells. In the CCOT group, Wnt1 and Wnt5a were identified in the epithelium and in the ghost cells in almost all the cases, and β-catenin was mainly identified in the cytoplasm and in the nuclei of the tumoral cells. Conclusions These results contribute to support the importance of Wnt/β-catenin signaling pathway proteins in AME and CCOT tumorigenesis. The abnormal expression of cytoplasmic and/or nuclear β-catenin appears to contribute to the development of both AME and CCOT. In addition, it is possible that Wnt1 and Wnt5a expression in ghost cells can contribute to its histogenesis in CCOT. Key words:Ameloblastoma, β-catenin, calcifying cystic odontogenic tumor, immunohistochemistry, Wnt. PMID:28149478

  8. Feedback Activation of Basic Fibroblast Growth Factor Signaling via the Wnt/β-Catenin Pathway in Skin Fibroblasts.

    Science.gov (United States)

    Wang, Xu; Zhu, Yuting; Sun, Congcong; Wang, Tao; Shen, Yingjie; Cai, Wanhui; Sun, Jia; Chi, Lisha; Wang, Haijun; Song, Na; Niu, Chao; Shen, Jiayi; Cong, Weitao; Zhu, Zhongxin; Xuan, Yuanhu; Li, Xiaokun; Jin, Litai

    2017-01-01

    Skin wound healing is a complex process requiring the coordinated behavior of many cell types, especially in the proliferation and migration of fibroblasts. Basic fibroblast growth factor (bFGF) is a member of the FGF family that promotes fibroblast migration, but the underlying molecular mechanism remains elusive. The present RNA sequencing study showed that the expression levels of several canonical Wnt pathway genes, including Wnt2b, Wnt3, Wnt11, T-cell factor 7 (TCF7), and Frizzled 8 (FZD8) were modified by bFGF stimulation in fibroblasts. Enzyme-linked immunosorbent assay (ELISA) analysis also showed that Wnt pathway was activated under bFGF treatment. Furthermore, treatment of fibroblasts with lithium chloride or IWR-1, an inducer and inhibitor of the Wnt signaling pathway, respectively, promoted and inhibited cell migration. Also, levels of cytosolic glycogen synthase kinase 3 beta phosphorylated at serine(9) (pGSK3β Ser(9)) and nuclear β-catenin were increased upon exposure to bFGF. Molecular and biochemical assays indicated that phosphoinositide 3-kinase (PI3K) signaling activated the GSK3β/β-catenin/Wnt signaling pathway via activation of c-Jun N-terminal kinase (JNK), suggesting that PI3K and JNK act at the upstream of β-catenin. In contrast, knock-down of β-catenin delayed fibroblast cell migration even under bFGF stimulation. RNA sequencing analysis of β-catenin knock-down fibroblasts demonstrated that β-catenin positively regulated the transcription of bFGF and FGF21. Moreover, FGF21 treatment activated AKT and JNK, and accelerated fibroblast migration to a similar extent as bFGF does. In addition, ELISA analysis demonstrated that both of bFGF and FGF21 were auto secretion factor and be regulated by Wnt pathway stimulators. Taken together, our analyses define a feedback regulatory loop between bFGF (FGF21) and Wnt signaling acting through β-catenin in skin fibroblasts.

  9. WNT signaling suppression in the senescent human thymus.

    Science.gov (United States)

    Ferrando-Martínez, Sara; Ruiz-Mateos, Ezequiel; Dudakov, Jarrod A; Velardi, Enrico; Grillari, Johannes; Kreil, David P; Muñoz-Fernandez, M Ángeles; van den Brink, Marcel R M; Leal, Manuel

    2015-03-01

    Human thymus is completely developed in late fetal stages and its function peaks in newborns. After the first year of life, the thymus undergoes a progressive atrophy that dramatically decreases de novo T-lymphocyte maturation. Hormonal signaling and changes in the microRNA expression network are identified as underlying causes of human thymus involution. However, specific pathways involved in the age-related loss of thymic function remain unknown. In this study, we analyzed differential gene-expression profile and microRNA expression in elderly (70 years old) and young (less than 10 months old and 11 years old) human thymic samples. Our data have shown that WNT pathway deregulation through the overexpression of different inhibitors by the nonadipocytic component of the human thymus stimulates the age-related involution. These results are of particular interest because interference of WNT signaling has been demonstrated in both animal models and in vitro studies, with the three major hallmarks of thymic involution: (i) epithelial structure disruption, (ii) adipogenic process, and (iii) thymocyte development arrest. Thus, our results suggest that secreted inhibitors of the WNT pathway could be explored as a novel therapeutical target in the reversal of the age-related thymic involution.

  10. Functional Crosstalk Between WNT Signaling and Tyrosine Kinase Signaling in Cancer.

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    Anastas, Jaimie N

    2015-12-01

    Extensive molecular characterization of tumors has revealed that the activity of multiple signaling pathways is often simultaneously dampened or enhanced in cancer cells. Aberrant WNT signaling and tyrosine kinase signaling are two pathways that are frequently up- or downregulated in cancer. Although signaling pathways regulated by WNTs, tyrosine kinases, and other factors are often conceptualized as independent entities, the biological reality is likely much more complex. Understanding the mechanisms of crosstalk between multiple signal transduction networks is a key challenge for cancer researchers. The overall goals of this review are to describe mechanisms of crosstalk between WNT and tyrosine kinase pathways in cancer and to discuss how understanding intersections between WNT and tyrosine kinase signaling networks might be exploited to improve current therapies.

  11. Inhibition of melanogenesis by the pyridinyl imidazole class of compounds: possible involvement of the Wnt/β-catenin signaling pathway.

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    Barbara Bellei

    Full Text Available While investigating the role of p38 MAPK in regulating melanogenesis, we found that pyridinyl imidazole inhibitors class compounds as well as the analog compound SB202474, which does not inhibit p38 MAPK, suppressed both α-MSH-induced melanogenesis and spontaneous melanin synthesis. In this study, we demonstrated that the inhibitory activity of the pyridinyl imidazoles correlates with inhibition of the canonical Wnt/β-catenin pathway activity. Imidazole-treated cells showed a reduction in the level of Tcf/Lef target genes involved in the β-catenin signaling network, including ubiquitous genes such as Axin2, Lef1, and Wisp1 as well as cell lineage-restricted genes such as microphthalmia-associated transcription factor and dopachrome tautomerase. Although over-expression of the Wnt signaling pathway effector β-catenin slightly restored the melanogenic program, the lack of complete reversion suggested that the imidazoles interfered with β-catenin-dependent transcriptional activity rather than with β-catenin expression. Accordingly, we did not observe any significant change in β-catenin protein expression. The independence of p38 MAPK activity from the repression of Wnt/β-catenin signaling pathway was confirmed by small interfering RNA knockdown of p38 MAPK expression, which by contrast, stimulated β-catenin-driven gene expression. Our data demonstrate that the small molecule pyridinyl imidazoles possess two distinct and opposite mechanisms that modulate β-catenin dependent transcription: a p38 inhibition-dependent effect that stimulates the Wnt pathway by increasing β-catenin protein expression and an off-target mechanism that inhibits the pathway by repressing β-catenin protein functionality. The p38-independent effect seems to be dominant and, at least in B16-F0 cells, results in a strong block of the Wnt/β-catenin signaling pathway.

  12. Noncanonical Wnt/PCP signaling during vertebrate gastrulation.

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    Tada, Masazumi; Kai, Masatake

    2009-03-01

    The branch of the Wnt pathway, related to planar cell polarity signaling in Drosophila, is fundamental not only to the establishment of tissue polarity but also to a variety of morphogenetic processes in vertebrates. The genetic pathway has been noted for its similarity as well as divergence of between vertebrates and Drosophila. This review focuses on issues related to the complexity of the output of the planar cell polarity pathway during gastrulation in zebrafish and Xenopus and, to a lesser extent, during gastrulation/neurulation in mice.

  13. Wnt3 and Wnt3a are required for induction of the mid-diencephalic organizer in the caudal forebrain

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    Mattes Benjamin

    2012-04-01

    Full Text Available Abstract Background A fundamental requirement for development of diverse brain regions is the function of local organizers at morphological boundaries. These organizers are restricted groups of cells that secrete signaling molecules, which in turn regulate the fate of the adjacent neural tissue. The thalamus is located in the caudal diencephalon and is the central relay station between the sense organs and higher brain areas. The mid-diencephalic organizer (MDO orchestrates the development of the thalamus by releasing secreted signaling molecules such as Shh. Results Here we show that canonical Wnt signaling in the caudal forebrain is required for the formation of the Shh-secreting MD organizer in zebrafish. Wnt signaling induces the MDO in a narrow time window of 4 hours - between 10 and 14 hours post fertilization. Loss of Wnt3 and Wnt3a prevents induction of the MDO, a phenotype also observed upon blockage of canonical Wnt signaling per se. Pharmaceutical activation of the canonical Wnt pathways in Wnt3/Wnt3a compound morphant embryos is able to restore the lack of the MDO. After blockage of Wnt signaling or knock-down of Wnt3/Wnt3a we find an increase of apoptotic cells specifically within the organizer primordium. Consistently, blockage of apoptosis restores the thalamus organizer MDO in Wnt deficient embryos. Conclusion We have identified canonical Wnt signaling as a novel pathway, that is required for proper formation of the MDO and consequently for the development of the major relay station of the brain - the thalamus. We propose that Wnt ligands are necessary to maintain the primordial tissue of the organizer during somitogenesis by suppressing Tp53-mediated apoptosis.

  14. Inhibition of p300 histone acetyltransferase activity in palate mesenchyme cells attenuates Wnt signaling via aberrant E-cadherin expression.

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    Warner, Dennis R; Smith, Scott C; Smolenkova, Irina A; Pisano, M Michele; Greene, Robert M

    2016-03-01

    p300 is a multifunctional transcriptional coactivator that interacts with numerous transcription factors and exhibits protein/histone acetyltransferase activity. Loss of p300 function in humans and in mice leads to craniofacial defects. In this study, we demonstrated that inhibition of p300 histone acetyltransferase activity with the compound, C646, altered the expression of several genes, including Cdh1 (E-cadherin) in mouse maxillary mesenchyme cells, which are the cells that give rise to the secondary palate. The increased expression of plasma membrane-bound E-cadherin was associated with reduced cytosolic β-catenin, that led to attenuated signaling through the canonical Wnt pathway. Furthermore, C646 reduced both cell proliferation and the migratory ability of these cells. These results suggest that p300 histone acetyltransferase activity is critical for Wnt-dependent palate mesenchymal cell proliferation and migration, both processes that play a significant role in morphogenesis of the palate.

  15. The effect of Wnt/β-catenin signaling pathway on dentinogenesis and dentin regeneration%Wnt/β-catenin信号通路影响牙本质形成及再生的研究进展

    Institute of Scientific and Technical Information of China (English)

    车彦霖; 吴家媛

    2016-01-01

    Wnt/β⁃catenin信号通路是Wnt通路中的经典途径,在牙的发生中发挥着重要作用。研究表明,Wnt/β⁃catenin信号通路在牙本质的形成过程中扮演着重要角色,本文就近年来相关研究对Wnt/β⁃catenin信号通路在成牙本质细胞分化和牙本质发生及再生中的作用及影响作一阐述。%Wnt/β⁃catenin signaling pathway is a canonical way which has an important influence on the tooth development. Many recent studies showed that it also plays an essential role during the dentin formation. This review aims to explain the effect of Wnt/β⁃catenin signaling pathway on odontoblast differentiation,dentinogenesis and dentin regeneration.

  16. The Wnt/β-catenin signaling pathway controls the inflammatory response in infections caused by pathogenic bacteria.

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    Silva-García, Octavio; Valdez-Alarcón, Juan J; Baizabal-Aguirre, Víctor M

    2014-01-01

    Innate immunity against pathogenic bacteria is critical to protect host cells from invasion and infection as well as to develop an appropriate adaptive immune response. During bacterial infection, different signaling transduction pathways control the expression of a wide range of genes that orchestrate a number of molecular and cellular events to eliminate the invading microorganisms and regulate inflammation. The inflammatory response must be tightly regulated because uncontrolled inflammation may lead to tissue injury. Among the many signaling pathways activated, the canonical Wnt/β-catenin has been recently shown to play an important role in the expression of several inflammatory molecules during bacterial infections. Our main goal in this review is to discuss the mechanism used by several pathogenic bacteria to modulate the inflammatory response through the Wnt/β-catenin signaling pathway. We think that a deep insight into the role of Wnt/β-catenin signaling in the inflammation may open new venues for biotechnological approaches designed to control bacterial infectious diseases.

  17. Brg1 loss attenuates aberrant wnt-signalling and prevents wnt-dependent tumourigenesis in the murine small intestine.

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    Aliaksei Z Holik

    2014-07-01

    Full Text Available Tumourigenesis within the intestine is potently driven by deregulation of the Wnt pathway, a process epigenetically regulated by the chromatin remodelling factor Brg1. We aimed to investigate this interdependency in an in vivo setting and assess the viability of Brg1 as a potential therapeutic target. Using a range of transgenic approaches, we deleted Brg1 in the context of Wnt-activated murine small intestinal epithelium. Pan-epithelial loss of Brg1 using VillinCreERT2 and AhCreERT transgenes attenuated expression of Wnt target genes, including a subset of stem cell-specific genes and suppressed Wnt-driven tumourigenesis improving animal survival. A similar increase in survival was observed when Wnt activation and Brg1 loss were restricted to the Lgr5 expressing intestinal stem cell population. We propose a mechanism whereby Brg1 function is required for aberrant Wnt signalling and ultimately for the maintenance of the tumour initiating cell compartment, such that loss of Brg1 in an Apc-deficient context suppresses adenoma formation. Our results highlight potential therapeutic value of targeting Brg1 and serve as a proof of concept that targeting the cells of origin of cancer may be of therapeutic relevance.

  18. The role of Wnt signaling in neuronal dysfunction in Alzheimer's Disease

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    Toledo Enrique M

    2008-07-01

    Full Text Available Abstract Recent evidence supports a neuroprotective role for Wnt signaling in neurodegenerative disorders such as Alzheimer's Disease (AD. In fact, a relationship between amyloid-β-peptide (Aβ-induced neurotoxicity and a decrease in the cytoplasmic levels of β-catenin has been observed. Apparently Aβ binds to the extracellular cysteine-rich domain of the Frizzled receptor (Fz inhibiting Wnt/β-catenin signaling. Cross-talk with other signaling cascades that regulate Wnt/β-catenin signaling, including the activation of M1 muscarinic receptor and PKC, the use of Ibuprofen-ChE bi-functional compounds, PPAR α, γ agonists, nicotine and some antioxidants, results in neuroprotection against Aβ. These studies indicate that a sustained loss of Wnt signaling function may be involved in the Aβ-dependent neurodegeneration observed in Alzheimer's brain. In conclusion the activation of the Wnt signaling pathway could be proposed as a therapeutic target for the treatment of AD.

  19. Aberrant WNT/β-catenin signaling in parathyroid carcinoma

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    Åkerström Göran

    2010-11-01

    Full Text Available Abstract Background Parathyroid carcinoma (PC is a very rare malignancy with a high tendency to recur locally, and recurrent disease is difficult to eradicate. In most western European countries and United States, these malignant neoplasms cause less than 1% of the cases with primary hyperparathyroidism, whereas incidence as high as 5% have been reported from Italy, Japan, and India. The molecular etiology of PC is poorly understood. Results The APC (adenomatous polyposis coli tumor suppressor gene was inactivated by DNA methylation in five analyzed PCs, as determined by RT-PCR, Western blotting, and quantitative bisulfite pyrosequencing analyses. This was accompanied by accumulation of stabilized active nonphosphorylated β-catenin, strongly suggesting aberrant activation of the WNT/β-catenin signaling pathway in these tumors. Treatment of a primary PC cell culture with the DNA hypomethylating agent 5-aza-2'-deoxycytidine (decitabine, Dacogen(r induced APC expression, reduced active nonphosphorylated β-catenin, inhibited cell growth, and caused apoptosis. Conclusion Aberrant WNT/β-catenin signaling by lost expression and DNA methylation of APC, and accumulation of active nonphosphorylated β-catenin was observed in the analyzed PCs. We suggest that adjuvant epigenetic therapy should be considered as an additional option in the treatment of patients with recurrent or metastatic parathyroid carcinoma.

  20. Canonical Sonic Hedgehog Signaling in Early Lung Development

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    Hugo Fernandes-Silva

    2017-03-01

    Full Text Available The canonical hedgehog (HH signaling pathway is of major importance during embryonic development. HH is a key regulatory morphogen of numerous cellular processes, namely, cell growth and survival, differentiation, migration, and tissue polarity. Overall, it is able to trigger tissue-specific responses that, ultimately, contribute to the formation of a fully functional organism. Of all three HH proteins, Sonic Hedgehog (SHH plays an essential role during lung development. In fact, abnormal levels of this secreted protein lead to severe foregut defects and lung hypoplasia. Canonical SHH signal transduction relies on the presence of transmembrane receptors, such as Patched1 and Smoothened, accessory proteins, as Hedgehog-interacting protein 1, and intracellular effector proteins, like GLI transcription factors. Altogether, this complex signaling machinery contributes to conveying SHH response. Pulmonary morphogenesis is deeply dependent on SHH and on its molecular interactions with other signaling pathways. In this review, the role of SHH in early stages of lung development, specifically in lung specification, primary bud formation, and branching morphogenesis is thoroughly reviewed.

  1. Inhibitory mechanisms of two Uncaria tomentosa extracts affecting the Wnt-signaling pathway.

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    Gurrola-Díaz, Carmen Magdalena; García-López, Pedro Macedonio; Gulewicz, Krzysztof; Pilarski, Radoslaw; Dihlmann, Susanne

    2011-06-15

    Uncaria tomentosa ("uña de gato"; "cat's claw"), a woody vine native to the Amazon rainforest, is commonly used in South American traditional medicine to treat a broad spectrum of diseases. Although recent studies have reported anti-inflammatory and anti-proliferative properties of different alkaloids extracted from this plant, the underlying molecular mechanisms of these effects have not been elucidated yet. Our study investigates the inhibitory mechanisms of Uncaria tomentosa extracts on the Wnt-signaling pathway, a central regulator of development and tissue homoeostasis. A modified cell-based luciferase assay for screening inhibitors of the Wnt-pathway was used for analysis. Three cancer cell lines displaying different levels of aberrant Wnt-signaling activity were transfected with Wnt-signaling responsive Tcf-reporter plasmids and treated with increasing concentrations of two Uncaria tomentosa bark extracts. Wnt-signaling activity was assessed by luciferase activity and by expression of Wnt-responsive target genes. We show that both, an aqueous and an alkaloid-enriched extract specifically inhibit Wnt-signaling activity in HeLa, HCT116 and SW480 cancer cells resulting in reduced expression of the Wnt-target gene: c-Myc. The alkaloid-enriched extract (B/S(rt)) was found to be more effective than the aqueous extract (B/W(37)). The strongest effect was observed in SW480 cells, displaying the highest endogenous Wnt-signaling activity. Downregulation of Wnt-signaling by a dominant negative-TCF-4 variant in non-cancer cells rendered the cells insensitive towards treatment with B/S(rt). B/Srt was less toxic in non-cancer cells than in cancer cells. Our data suggest that the broad spectrum of pharmacological action of Uncaria tomentosa involves inhibition of the Wnt-signaling pathway, downstream of beta-Catenin activity.

  2. WIKI4, a novel inhibitor of tankyrase and Wnt/ß-catenin signaling.

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    Richard G James

    Full Text Available The Wnt/ß-catenin signaling pathway controls important cellular events during development and often contributes to disease when dysregulated. Using high throughput screening we have identified a new small molecule inhibitor of Wnt/ß-catenin signaling, WIKI4. WIKI4 inhibits expression of ß-catenin target genes and cellular responses to Wnt/ß-catenin signaling in cancer cell lines as well as in human embryonic stem cells. Furthermore, we demonstrate that WIKI4 mediates its effects on Wnt/ß-catenin signaling by inhibiting the enzymatic activity of TNKS2, a regulator of AXIN ubiquitylation and degradation. While TNKS has previously been shown to be the target of small molecule inhibitors of Wnt/ß-catenin signaling, WIKI4 is structurally distinct from previously identified TNKS inhibitors.

  3. Chronic chemotherapeutic stress promotes evolution of stemness and WNT/beta-catenin signaling in colorectal cancer cells: implications for clinical use of WNT-signaling inhibitors

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    Ayadi, Meriam; Bouygues, Anaïs; Ouaret, Djamila; Ferrand, Nathalie; Chouaib, Salem; Thiery, Jean-Paul; Muchardt, Christian; Sabbah, Michèle; Larsen, Annette K

    2015-01-01

    Most solid tumors contain a subfraction of cells with stem/progenitor cell features. Stem cells are naturally chemoresistant suggesting that chronic chemotherapeutic stress may select for cells with increased “stemness”. We carried out a comprehensive molecular and functional analysis of six independently selected colorectal cancer (CRC) cell lines with acquired resistance to three different chemotherapeutic agents derived from two distinct parental cell lines. Chronic drug exposure resulted in complex alterations of stem cell markers that could be classified into three categories: 1) one cell line, HT-29/5-FU, showed increased “stemness” and WNT-signaling, 2) three cell lines showed decreased expression of stem cell markers, decreased aldehyde dehydrogenase activity, attenuated WNT-signaling and lost the capacity to form colonospheres and 3) two cell lines displayed prominent expression of ABC transporters with a heterogeneous response for stem cell markers. While WNT-signaling could be attenuated in the HT-29/5-FU cells by the WNT-signaling inhibitors ICG-001 and PKF-118, this was not accompanied by any selective growth inhibitory effect suggesting that the cytotoxic activity of these compounds is not directly linked to WNT-signaling inhibition. We conclude that classical WNT-signaling inhibitors have toxic off-target activities that need to be addressed for clinical development. PMID:26041882

  4. Crosstalk between SOXB1 proteins and WNT/β-catenin signaling in NT2/D1 cells.

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    Mojsin, Marija; Topalovic, Vladanka; Vicentic, Jelena Marjanovic; Schwirtlich, Marija; Stanisavljevic, Danijela; Drakulic, Danijela; Stevanovic, Milena

    2015-11-01

    During early vertebrate embryogenesis, the expression of SOXB1 proteins is precisely regulated by a number of different mechanisms, including Wnt/β-catenin signaling. This is essential for controlling the balance between stemness and differentiation in embryonic stem cells. In the present study, we analyzed the molecular mechanism of LiCl action in NT2/D1 cells and examined the crosstalk between SOXB1 proteins and Wnt signaling in this model system. We have shown that LiCl increases β-catenin level, induces its translocation to the nucleus and consequently up-regulates β-catenin/Tcf-dependent transcription in NT2/D1 cells. Our results also suggest that LiCl treatment leads to increased expression of SOX2 and SOX3 proteins in NT2/D1 cells through activation of canonical Wnt signaling. Finally, we have detected a negative feedback loop between β-catenin and SOX2 expression in NT2/D1 cells. Since β-catenin and SOX2 have been linked to processes of self-renewal and pluripotency, our results have implications for future research on the maintenance of stemness and lineage commitment of embryonic stem cells.

  5. Remote activation of the Wnt/β-catenin signalling pathway using functionalised magnetic particles.

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    Rotherham, Michael; El Haj, Alicia J

    2015-01-01

    Wnt signalling pathways play crucial roles in developmental biology, stem cell fate and tissue patterning and have become an attractive therapeutic target in the fields of tissue engineering and regenerative medicine. Wnt signalling has also been shown to play a role in human Mesenchymal Stem Cell (hMSC) fate, which have shown potential as a cell therapy in bone and cartilage tissue engineering. Previous work has shown that biocompatible magnetic nanoparticles (MNP) can be used to stimulate specific mechanosensitive membrane receptors and ion channels in vitro and in vivo. Using this strategy, we determined the effects of mechano-stimulation of the Wnt Frizzled receptor on Wnt pathway activation in hMSC. Frizzled receptors were tagged using anti-Frizzled functionalised MNP (Fz-MNP). A commercially available oscillating magnetic bioreactor (MICA Biosystems) was used to mechanically stimulate Frizzled receptors remotely. Our results demonstrate that Fz-MNP can activate Wnt/β-catenin signalling at key checkpoints in the signalling pathway. Immunocytochemistry indicated nuclear localisation of the Wnt intracellular messenger β-catenin after treatment with Fz-MNP. A Wnt signalling TCF/LEF responsive luciferase reporter transfected into hMSC was used to assess terminal signal activation at the nucleus. We observed an increase in reporter activity after treatment with Fz-MNP and this effect was enhanced after mechano-stimulation using the magnetic array. Western blot analysis was used to probe the mechanism of signalling activation and indicated that Fz-MNP signal through an LRP independent mechanism. Finally, the gene expression profiles of stress response genes were found to be similar when cells were treated with recombinant Wnt-3A or Fz-MNP. This study provides proof of principle that Wnt signalling and Frizzled receptors are mechanosensitive and can be remotely activated in vitro. Using magnetic nanoparticle technology it may be possible to modulate Wnt signalling

  6. Remote activation of the Wnt/β-catenin signalling pathway using functionalised magnetic particles.

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    Michael Rotherham

    Full Text Available Wnt signalling pathways play crucial roles in developmental biology, stem cell fate and tissue patterning and have become an attractive therapeutic target in the fields of tissue engineering and regenerative medicine. Wnt signalling has also been shown to play a role in human Mesenchymal Stem Cell (hMSC fate, which have shown potential as a cell therapy in bone and cartilage tissue engineering. Previous work has shown that biocompatible magnetic nanoparticles (MNP can be used to stimulate specific mechanosensitive membrane receptors and ion channels in vitro and in vivo. Using this strategy, we determined the effects of mechano-stimulation of the Wnt Frizzled receptor on Wnt pathway activation in hMSC. Frizzled receptors were tagged using anti-Frizzled functionalised MNP (Fz-MNP. A commercially available oscillating magnetic bioreactor (MICA Biosystems was used to mechanically stimulate Frizzled receptors remotely. Our results demonstrate that Fz-MNP can activate Wnt/β-catenin signalling at key checkpoints in the signalling pathway. Immunocytochemistry indicated nuclear localisation of the Wnt intracellular messenger β-catenin after treatment with Fz-MNP. A Wnt signalling TCF/LEF responsive luciferase reporter transfected into hMSC was used to assess terminal signal activation at the nucleus. We observed an increase in reporter activity after treatment with Fz-MNP and this effect was enhanced after mechano-stimulation using the magnetic array. Western blot analysis was used to probe the mechanism of signalling activation and indicated that Fz-MNP signal through an LRP independent mechanism. Finally, the gene expression profiles of stress response genes were found to be similar when cells were treated with recombinant Wnt-3A or Fz-MNP. This study provides proof of principle that Wnt signalling and Frizzled receptors are mechanosensitive and can be remotely activated in vitro. Using magnetic nanoparticle technology it may be possible to modulate

  7. Tyrosine-based signal mediates LRP6 receptor endocytosis and desensitization of Wnt/β-catenin pathway signaling.

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    Liu, Chia-Chen; Kanekiyo, Takahisa; Roth, Barbara; Bu, Guojun

    2014-10-03

    Wnt/β-catenin signaling orchestrates a number of critical events including cell growth, differentiation, and cell survival during development. Misregulation of this pathway leads to various human diseases, specifically cancers. Endocytosis and phosphorylation of the LDL receptor-related protein 6 (LRP6), an essential co-receptor for Wnt/β-catenin signaling, play a vital role in mediating Wnt/β-catenin signal transduction. However, its regulatory mechanism is not fully understood. In this study, we define the mechanisms by which LRP6 endocytic trafficking regulates Wnt/β-catenin signaling activation. We show that LRP6 mutant with defective tyrosine-based signal in its cytoplasmic tail has an increased cell surface distribution and decreased endocytosis rate. These changes in LRP6 endocytosis coincide with an increased distribution to caveolae, increased phosphorylation, and enhanced Wnt/β-catenin signaling. We further demonstrate that treatment of Wnt3a ligands or blocking the clathrin-mediated endocytosis of LRP6 leads to a redistribution of wild-type receptor to lipid rafts. The LRP6 tyrosine mutant also exhibited an increase in signaling activation in response to Wnt3a stimulation when compared with wild-type LRP6, and this activation is suppressed when caveolae-mediated endocytosis is blocked. Our results reveal molecular mechanisms by which LRP6 endocytosis routes regulate its phosphorylation and the strength of Wnt/β-catenin signaling, and have implications on how this pathway can be modulated in human diseases.

  8. Wnt signaling pathway: implications for therapy in lung cancer and bone metastasis.

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    Xi, Yongming; Chen, Yan

    2014-10-10

    Lung cancer remains a major worldwide health problem and patients have high rate of metastasis including bone. Although pathologic characteristics of this disease are clear and well established, much remains to be understood about this tumor, particularly at the molecular signaling level. Secreted signaling molecules of the Wnt family have been widely investigated and found to play a prominent role to induce human malignant diseases, such as breast and prostate cancer. A variety of studies have also demonstrated that the Wnt signaling pathway is closely associated with bone malignancies including osteosarcoma, multiple myeloma, and breast or prostate cancer induced bone metastasis. The aim of this review is to provide a summary regarding the role of the Wnt signaling pathway in lung cancer and bone metastasis, highlighting the aberrant activation of Wnt in this malignancy. We also discuss the potential therapeutic applications for the treatment of lung cancer and cancer induced bone metastasis targeting the Wnt pathway.

  9. Fresh WNT into the regulation of mitosis.

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    Stolz, Ailine; Bastians, Holger

    2015-01-01

    Canonical Wnt signaling triggering β-catenin-dependent gene expression contributes to cell cycle progression, in particular at the G1/S transition. Recently, however, it became clear that the cell cycle can also feed back on Wnt signaling at the G2/M transition. This is illustrated by the fact that mitosis-specific cyclin-dependent kinases can phosphorylate the Wnt co-receptor LRP6 to prime the pathway for incoming Wnt signals when cells enter mitosis. In addition, there is accumulating evidence that various Wnt pathway components might exert additional, Wnt-independent functions that are important for proper regulation of mitosis. The importance of Wnt pathways during mitosis was most recently enforced by the discovery of Wnt signaling contributing to the stabilization of proteins other than β-catenin, specifically at G2/M and during mitosis. This Wnt-mediated stabilization of proteins, now referred to as Wnt/STOP, might on one hand contribute to maintaining a critical cell size required for cell division and, on the other hand, for the faithful execution of mitosis itself. In fact, most recently we have shown that Wnt/STOP is required for ensuring proper microtubule dynamics within mitotic spindles, which is pivotal for accurate chromosome segregation and for the maintenance of euploidy.

  10. SLIT/ROBO2 Signaling Promotes Mammary Stem Cell Senescence by Inhibiting Wnt Signaling

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    Gwyndolen Harburg

    2014-09-01

    Full Text Available WNT signaling stimulates the self-renewal of many types of adult stem cells, including mammary stem cells (MaSCs, but mechanisms that limit this activity are poorly understood. Here, we demonstrate that SLIT2 restricts stem cell renewal by signaling through ROBO2 in a subset of basal cells to negatively regulate WNT signaling. The absence of SLIT/ROBO2 signaling leads to increased levels of nuclear β-catenin. Robo2 loss does not increase the number of stem cells; instead, stem cell renewal is enhanced in the absence of SLIT/ROBO2 signaling. This is due to repressed expression of p16 INK4a, which, in turn, delays MaSC senescence. Together, our studies support a model in which SLITs restrict the expansion of MaSCs by countering the activity of WNTs and limiting self-renewal.

  11. Construction and Experimental Validation of a Petri Net Model of Wnt/β-Catenin Signaling.

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    Annika Jacobsen

    Full Text Available The Wnt/β-catenin signaling pathway is important for multiple developmental processes and tissue maintenance in adults. Consequently, deregulated signaling is involved in a range of human diseases including cancer and developmental defects. A better understanding of the intricate regulatory mechanism and effect of physiological (active and pathophysiological (hyperactive WNT signaling is important for predicting treatment response and developing novel therapies. The constitutively expressed CTNNB1 (commonly and hereafter referred to as β-catenin is degraded by a destruction complex, composed of amongst others AXIN1 and GSK3. The destruction complex is inhibited during active WNT signaling, leading to β-catenin stabilization and induction of β-catenin/TCF target genes. In this study we investigated the mechanism and effect of β-catenin stabilization during active and hyperactive WNT signaling in a combined in silico and in vitro approach. We constructed a Petri net model of Wnt/β-catenin signaling including main players from the plasma membrane (WNT ligands and receptors, cytoplasmic effectors and the downstream negative feedback target gene AXIN2. We validated that our model can be used to simulate both active (WNT stimulation and hyperactive (GSK3 inhibition signaling by comparing our simulation and experimental data. We used this experimentally validated model to get further insights into the effect of the negative feedback regulator AXIN2 upon WNT stimulation and observed an attenuated β-catenin stabilization. We furthermore simulated the effect of APC inactivating mutations, yielding a stabilization of β-catenin levels comparable to the Wnt-pathway activities observed in colorectal and breast cancer. Our model can be used for further investigation and viable predictions of the role of Wnt/β-catenin signaling in oncogenesis and development.

  12. Making sense of Wnt signaling – linking hair cell regeneration to development

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    Lina eJansson

    2015-03-01

    Full Text Available Wnt signaling is a highly conserved pathway crucial for development and homeostasis of multicellular organisms. Secreted Wnt ligands bind Frizzled receptors to regulate diverse processes such as axis patterning, cell division, and cell fate specification. They also serve to govern self-renewal of somatic stem cells in several adult tissues. The complexity of the pathway can be attributed to the myriad of Wnt and Frizzled combinations as well as its diverse context-dependent functions. In the developing mouse inner ear, Wnt signaling plays diverse roles, including specification of the otic placode and patterning of the otic vesicle. At later stages, its activity governs sensory hair cell specification, cell cycle regulation, and hair cell orientation. In regenerating sensory organs from non-mammalian species, Wnt signaling can also regulate the extent of proliferative hair cell regeneration. This review describes the current knowledge of the roles of Wnt signaling and Wnt-responsive cells in hair cell development and regeneration. We also discuss possible future directions and the potential application and limitation of Wnt signaling in augmenting hair cell regeneration.

  13. The Wnt pathway: a key network in cell signalling dysregulated by viruses.

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    van Zuylen, Wendy J; Rawlinson, William D; Ford, Caroline E

    2016-09-01

    Viruses are obligate parasites dependent on host cells for survival. Viral infection of a cell activates a panel of pattern recognition receptors that mediate antiviral host responses to inhibit viral replication and dissemination. Viruses have evolved mechanisms to evade and subvert this antiviral host response, including encoding proteins that hijack, mimic and/or manipulate cellular processes such as the cell cycle, DNA damage repair, cellular metabolism and the host immune response. Currently, there is an increasing interest whether viral modulation of these cellular processes, including the cell cycle, contributes to cancer development. One cellular pathway related to cell cycle signalling is the Wnt pathway. This review focuses on the modulation of this pathway by human viruses, known to cause (or associated with) cancer development. The main mechanisms where viruses interact with the Wnt pathway appear to be through (i) epigenetic modification of Wnt genes; (ii) cellular or viral miRNAs targeting Wnt genes; (iii) altering specific Wnt pathway members, often leading to (iv) nuclear translocation of β-catenin and activation of Wnt signalling. Given that diverse viruses affect this signalling pathway, modulating Wnt signalling could be a generalised critical process for the initiation or maintenance of viral pathogenesis, with resultant dysregulation contributing to virus-induced cancers. Further study of this virus-host interaction may identify options for targeted therapy against Wnt signalling molecules as a means to reduce virus-induced pathogenesis and the downstream consequences of infection. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Wnt/β-catenin pathway regulates MGMT gene expression in cancer and inhibition of Wnt signalling prevents chemoresistance.

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    Wickström, Malin; Dyberg, Cecilia; Milosevic, Jelena; Einvik, Christer; Calero, Raul; Sveinbjörnsson, Baldur; Sandén, Emma; Darabi, Anna; Siesjö, Peter; Kool, Marcel; Kogner, Per; Baryawno, Ninib; Johnsen, John Inge

    2015-11-25

    The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) is commonly overexpressed in cancers and is implicated in the development of chemoresistance. The use of drugs inhibiting MGMT has been hindered by their haematologic toxicity and inefficiency. As a different strategy to inhibit MGMT we investigated cellular regulators of MGMT expression in multiple cancers. Here we show a significant correlation between Wnt signalling and MGMT expression in cancers with different origin and confirm the findings by bioinformatic analysis and immunofluorescence. We demonstrate Wnt-dependent MGMT gene expression and cellular co-localization between active β-catenin and MGMT. Pharmacological or genetic inhibition of Wnt activity downregulates MGMT expression and restores chemosensitivity of DNA-alkylating drugs in mouse models. These findings have potential therapeutic implications for chemoresistant cancers, especially of brain tumours where the use of temozolomide is frequently used in treatment.

  15. A role for Wnt/planar cell polarity signaling during lens fiber cell differentiation?

    Science.gov (United States)

    Chen, Y; Stump, R J W; Lovicu, F J; McAvoy, J W

    2006-12-01

    Wnt signaling through frizzled (Fz) receptors plays key roles in just about every developmental system that has been studied. Several Wnt-Fz signaling pathways have been identified including the Wnt/planar cell polarity (PCP) pathway. PCP signaling is crucial for many developmental processes that require major cytoskeletal rearrangements. Downstream of Fz, PCP signaling is thought to involve the GTPases, Rho, Rac and Cdc42 and regulation of the JNK cascade. Here we report on the localization of these GTPases and JNK in the lens and assess their involvement in the cytoskeletal reorganisation that is a key element of FGF-induced lens fiber cell differentiation.

  16. A Glimpse of the Pathogenetic Mechanisms of Wnt/β-Catenin Signaling in Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Li Xiao

    2013-01-01

    Full Text Available The Wnt family of proteins belongs to a group of secreted lipid-modified glycoproteins with highly conserved cysteine residues. Prior results indicate that Wnt/β-catenin signaling plays a prominent role in cell differentiation, adhesion, survival, and apoptosis and is involved in organ development, tumorigenesis, and tissue fibrosis, among other functions. Accumulating evidence has suggested that Wnt/β-catenin exhibits a pivotal function in the progression of diabetic nephropathy (DN. In this review, we focused on discussing the dual role of Wnt/β-catenin in apoptosis and epithelial mesenchymal transition (EMT formation of mesangial cells. Moreover, we also elucidated the effect of Wnt/β-catenin in podocyte dysfunction, tubular EMT formation, and renal fibrosis under DN conditions. In addition, the molecular mechanisms involved in this process are introduced. This information provides a novel molecular target of Wnt/β-catenin for the protection of kidney damage and in delay of the progression of DN.

  17. A late requirement for Wnt and FGF signaling during activin-induced formation of foregut endoderm from mouse embryonic stem cells

    DEFF Research Database (Denmark)

    Hansson, Mattias; Olesen, Dorthe R; Peterslund, Janny M L

    2009-01-01

    Here we examine how BMP, Wnt, and FGF signaling modulate activin-induced mesendodermal differentiation of mouse ES cells grown under defined conditions in adherent monoculture. We monitor ES cells containing reporter genes for markers of primitive streak (PS) and its progeny and extend previous....... Notably, activin induction of Gsc-GFP(+) cells appears refractory to inhibition of canonical Wnt signaling but shows a dependence on early as well as late FGF signaling. Additionally, we find a late dependence on FGF signaling during induction of Sox17(+) cells by activin while BMP4-induced T expression...... requires FGF signaling in adherent but not aggregate culture. Lastly, we demonstrate that activin-induced definitive endoderm derived from mouse ES cells can incorporate into the developing foregut endoderm in vivo and adopt a mostly anterior foregut character after further culture in vitro....

  18. CTHRC1 Acts as a Prognostic Factor and Promotes Invasiveness of Gastrointestinal Stromal Tumors by Activating Wnt/PCP-Rho Signaling

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    Ming-Ze Ma

    2014-03-01

    Full Text Available Gastrointestinal stromal tumors (GISTs are the major gastrointestinal mesenchymal tumors with a variable malignancy ranging from a curable disorder to highly malignant sarcomas. Metastasis and recurrence are the main causes of death in GIST patients. To further explore the mechanism of metastasis and to more accurately estimate the recurrence risk of GISTs after surgery, the clinical significance and functional role of collagen triple helix repeat containing-1 (CTHRC1 in GIST were investigated. We found that CTHRC1 expression was gradually elevated as the risk grade of NIH classification increased, and was closely correlated with disease-free survival and overall survival in 412 GIST patients. In vitro experiments showed that recombinant CTHRC1 protein promoted the migration and invasion capacities of primary GIST cells. A luciferase reporter assay and pull down assay demonstrated that recombinant CTHRC1 protein activated noncanonical Wnt/PCP-Rho signaling but inhibited canonical Wnt signaling. The pro-motility effect of CTHRC1 on GIST cells was reversed by using a Wnt5a neutralizing antibody and inhibitors of Rac1 or ROCK. Taken together, these data indicate that CTHRC1 may serve as a new predictor of recurrence risk and prognosis in post-operative GIST patients and may play an important role in facilitating GIST progression. Furthermore, CTHRC1 promotes GIST cell migration and invasion by activating Wnt/PCP-Rho signaling, suggesting that the CTHRC1-Wnt/PCP-Rho axis may be a new therapeutic target for interventions against GIST invasion and metastasis.

  19. Stem cell signaling. An integral program for tissue renewal and regeneration: Wnt signaling and stem cell control.

    Science.gov (United States)

    Clevers, Hans; Loh, Kyle M; Nusse, Roel

    2014-10-03

    Stem cells fuel tissue development, renewal, and regeneration, and these activities are controlled by the local stem cell microenvironment, the "niche." Wnt signals emanating from the niche can act as self-renewal factors for stem cells in multiple mammalian tissues. Wnt proteins are lipid-modified, which constrains them to act as short-range cellular signals. The locality of Wnt signaling dictates that stem cells exiting the Wnt signaling domain differentiate, spatially delimiting the niche in certain tissues. In some instances, stem cells may act as or generate their own niche, enabling the self-organization of patterned tissues. In this Review, we discuss the various ways by which Wnt operates in stem cell control and, in doing so, identify an integral program for tissue renewal and regeneration.

  20. Estrogen-related receptor α regulates osteoblast differentiation via Wnt/β-catenin signaling.

    Science.gov (United States)

    Auld, Kathryn L; Berasi, Stephen P; Liu, Yan; Cain, Michael; Zhang, Ying; Huard, Christine; Fukayama, Shoichi; Zhang, Jing; Choe, Sung; Zhong, Wenyan; Bhat, Bheem M; Bhat, Ramesh A; Brown, Eugene L; Martinez, Robert V

    2012-04-01

    Based on its homology to the estrogen receptor and its roles in osteoblast and chondrocyte differentiation, the orphan nuclear receptor estrogen-related receptor α (ERRα (ESRRA)) is an intriguing therapeutic target for osteoporosis and other bone diseases. The objective of this study was to better characterize the molecular mechanisms by which ERRα modulates osteoblastogenesis. Experiments from multiple systems demonstrated that ERRα modulates Wnt signaling, a crucial pathway for proper regulation of bone development. This was validated using a Wnt-luciferase reporter, where ERRα showed co-activator-dependent (peroxisome proliferator-activated receptor gamma co-activator 1α, PGC-1α) stimulatory effects. Interestingly, knockdown of ERRα expression also enhanced WNT signaling. In combination, these data indicated that ERRα could serve to either activate or repress Wnt signaling depending on the presence or absence of its co-activator PGC-1α. The observed Wnt pathway modulation was cell intrinsic and did not alter β-catenin nuclear translocation but was dependent on DNA binding of ERRα. We also found that expression of active ERRα correlated with Wnt pathway effects on osteoblastic differentiation in two cell types, consistent with a role for ERRα in modulating the Wnt pathway. In conclusion, this work identifies ERRα, in conjunction with co-activators such as PGC-1α, as a new regulator of the Wnt-signaling pathway during osteoblast differentiation, through a cell-intrinsic mechanism not affecting β-catenin nuclear translocation.

  1. Salinomycin inhibits Wnt signaling and selectively induces apoptosis in chronic lymphocytic leukemia cells.

    Science.gov (United States)

    Lu, Desheng; Choi, Michael Y; Yu, Jian; Castro, Januario E; Kipps, Thomas J; Carson, Dennis A

    2011-08-09

    Salinomycin, an antibiotic potassium ionophore, has been reported recently to act as a selective breast cancer stem cell inhibitor, but the biochemical basis for its anticancer effects is not clear. The Wnt/β-catenin signal transduction pathway plays a central role in stem cell development, and its aberrant activation can cause cancer. In this study, we identified salinomycin as a potent inhibitor of the Wnt signaling cascade. In Wnt-transfected HEK293 cells, salinomycin blocked the phosphorylation of the Wnt coreceptor lipoprotein receptor related protein 6 (LRP6) and induced its degradation. Nigericin, another potassium ionophore with activity against cancer stem cells, exerted similar effects. In otherwise unmanipulated chronic lymphocytic leukemia cells with constitutive Wnt activation nanomolar concentrations of salinomycin down-regulated the expression of Wnt target genes such as LEF1, cyclin D1, and fibronectin, depressed LRP6 levels, and limited cell survival. Normal human peripheral blood lymphocytes resisted salinomycin toxicity. These results indicate that ionic changes induced by salinomycin and related drugs inhibit proximal Wnt signaling by interfering with LPR6 phosphorylation, and thus impair the survival of cells that depend on Wnt signaling at the plasma membrane.

  2. HPV16 E6 and E6AP differentially cooperate to stimulate or augment Wnt signaling

    Energy Technology Data Exchange (ETDEWEB)

    Sominsky, Sophia, E-mail: sophia.tab@gmail.com [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Kuslansky, Yael, E-mail: ykuslansky@gmail.com [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Shapiro, Beny, E-mail: benyshap@gmail.com [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Jackman, Anna, E-mail: jackman@post.tau.ac.il [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Haupt, Ygal, E-mail: ygal.haupt@petermac.org [Research Division, The Peter MacCallum Cancer Centre, East Melbourne (Australia); Rosin-Arbesfeld, Rina, E-mail: arina@post.tau.ac.il [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Sherman, Levana, E-mail: lsherman@post.tau.ac.il [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel)

    2014-11-15

    The present study investigated the roles of E6 and E6AP in the Wnt pathway. We showed that E6 levels are markedly reduced in cells in which Wnt signaling is activated. Coexpression of wild-type or mutant E6AP (C820A) in Wnt-activated cells stabilized E6 and enhanced Wnt/β-catenin/TCF transcription. Expression of E6AP alone in nonstimulated cells elevated β-catenin level, promoted its nuclear accumulation, and activated β-catenin/TCF transcription. A knockdown of E6AP lowered β-catenin levels. Coexpression with E6 intensified the activities of E6AP. Further experiments proved that E6AP/E6 stabilize β-catenin by protecting it from proteasomal degradation. This function was dependent on the catalytic activity of E6AP, the kinase activity of GSK3β and the susceptibility of β-catenin to GSK3β phosphorylation. Thus, this study identified E6AP as a novel regulator of the Wnt signaling pathway, capable of cooperating with E6 in stimulating or augmenting Wnt/β-catenin signaling, thereby possibly contributing to HPV carcinogenesis. - Highlights: • The roles of E6 and E6AP in the Wnt pathway were investigated. • E6AP stabilizes E6 and enhances E6 activity in augmentation of Wnt signaling. • E6AP cooperates with E6 to stabilize β-catenin and stimulate Wnt/β-catenin signaling. • E6AP and E6 act through different mechanisms to augment or stimulate Wnt signaling.

  3. Notch and Wnt signaling mediated rod photoreceptor regeneration by Muller cells in adult mammalian retina.

    Directory of Open Access Journals (Sweden)

    Carolina Beltrame Del Debbio

    Full Text Available BACKGROUND: Evidence emerging from a variety of approaches used in different species suggests that Müller cell function may extend beyond its role of maintaining retinal homeostasis to that of progenitors in the adult retina. Enriched Müller cells in vitro or those that re-enter cell cycle in response to neurotoxin-damage to retina in vivo display multipotential and self-renewing capacities, the cardinal features of stem cells. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrate that Notch and Wnt signaling activate Müller cells through their canonical pathways and that a rare subset of activated Müller cells differentiates along rod photoreceptor lineage in the outer nuclear layer. The differentiation of activated Müller cells along photoreceptor lineage is confirmed by multiple approaches that included Hoechst dye efflux analysis, genetic analysis using retina from Nrl-GFP mice, and lineage tracing using GS-GFP lentivirus in wild type and rd mice in vitro and S334ter rats in vivo. Examination of S334ter rats for head-neck tracking of visual stimuli, a behavioral measure of light perception, demonstrates a significant improvement in light perception in animals treated to activate Müller cells. The number of activated Müller cells with rod photoreceptor phenotype in treated animals correlates with the improvement in their light perception. CONCLUSION/SIGNIFICANCE: In summary, our results provide a proof of principle for non-neurotoxin-mediated activation of Müller cells through Notch and Wnt signaling toward the regeneration of rod photoreceptors.

  4. A20 restricts wnt signaling in intestinal epithelial cells and suppresses colon carcinogenesis.

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    Ling Shao

    Full Text Available Colon carcinogenesis consists of a multistep process during which a series of genetic and epigenetic adaptations occur that lead to malignant transformation. Here, we have studied the role of A20 (also known as TNFAIP3, a ubiquitin-editing enzyme that restricts NFκB and cell death signaling, in intestinal homeostasis and tumorigenesis. We have found that A20 expression is consistently reduced in human colonic adenomas than in normal colonic tissues. To further investigate A20's potential roles in regulating colon carcinogenesis, we have generated mice lacking A20 specifically in intestinal epithelial cells and interbred these with mice harboring a mutation in the adenomatous polyposis coli gene (APC(min. While A20(FL/FL villin-Cre mice exhibit uninflamed intestines without polyps, A20(FL/FL villin-Cre APC(min/+ mice contain far greater numbers and larger colonic polyps than control APC(min mice. We find that A20 binds to the β-catenin destruction complex and restricts canonical wnt signaling by supporting ubiquitination and degradation of β-catenin in intestinal epithelial cells. Moreover, acute deletion of A20 from intestinal epithelial cells in vivo leads to enhanced expression of the β-catenin dependent genes cyclinD1 and c-myc, known promoters of colon cancer. Taken together, these findings demonstrate new roles for A20 in restricting β-catenin signaling and preventing colon tumorigenesis.

  5. Expression profile and function of Wnt signaling mechanisms in malignant mesothelioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Simon A., E-mail: s.fox@curtin.edu.au [Molecular Pharmacology Laboratory, School of Pharmacy, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA (Australia); Richards, Alex K.; Kusumah, Ivonne; Perumal, Vanathi [Molecular Pharmacology Laboratory, School of Pharmacy, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA (Australia); Bolitho, Erin M. [Western Australian Institute for Medical Research, The University of Western Australia Centre for Medical Research, Perth, WA (Australia); Mutsaers, Steven E. [Lung Institute of Western Australia, Centre for Asthma Allergy and Respiratory Research, University of Western Australia, Nedlands (Australia); Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, University of Western Australia and Western Australian Institute for Medical Research, Nedlands (Australia); Dharmarajan, Arun M. [School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA (Australia)

    2013-10-11

    Highlights: •Expression profile of Wnt pathway related genes in mesothelioma cells. •Differential expression of key Wnt pathway molecules and regulators. •Wnt3a stimulated mesothelioma growth whereas sFRP4 was inhibitory. •Targeting β-Catenin can sensitise mesothelioma cells to cytotoxic drugs. -- Abstract: Malignant mesothelioma (MM) is an uncommon and particularly aggressive cancer associated with asbestos exposure, which currently presents an intractable clinical challenge. Wnt signaling has been reported to play a role in the neoplastic properties of mesothelioma cells but has not been investigated in detail in this cancer. We surveyed expression of Wnts, their receptors, and other key molecules in this pathway in well established in vitro mesothelioma models in comparison with primary mesothelial cultures. We also tested the biological response of MM cell lines to exogenous Wnt and secreted regulators, as well as targeting β-catenin. We detected frequent expression of Wnt3 and Wnt5a, as well as Fzd 2, 4 and 6. The mRNA of Wnt4, Fzd3, sFRP4, APC and axin2 were downregulated in MM relative to mesothelial cells while LEF1 was overexpressed in MM. Functionally, we observed that Wnt3a stimulated MM proliferation while sFRP4 was inhibitory. Furthermore, directly targeting β-catenin expression could sensitise MM cells to cytotoxic drugs. These results provide evidence for altered expression of a number of Wnt/Fzd signaling molecules in MM. Modulation of Wnt signaling in MM may prove a means of targeting proliferation and drug resistance in this cancer.

  6. Wnt/β-catenin and its diverse physiological cell signaling pathways in neurodegenerative and neuropsychiatric disorders.

    Science.gov (United States)

    Al-Harthi, Lena

    2012-12-01

    Wnt signaling is a fundamental pathway in embryogenesis which is evolutionary conserved from metazoans to humans. Much of our understanding of Wnt signaling events emerged from key developmental studies in drosophila, zebra fish, xenopus, and mice. Considerable data now exists on the role of Wnt signaling beyond these developmental processes and in particular its role in health and disease. The focus of this special issue is on Wnt/β-catenin and its diverse physiological cell signaling pathways in neurodegenerative and neuropsychiatric disorders. This special issue is composed of six reviews and two original articles selected to highlight recent advances in the role of Wnt signaling in CNS embryonic development, in adult brain function, in neurodegenerative conditions such as Alzheimer's disease, schizophrenia, NeuroAIDS, and in gliomas. The finding that β-catenin can translocate to the nucleus where it binds to TCF/LEF transcription factors to regulate target gene expression was a seminal observation that linked β-catenin/LEF to T cell development and differentiation. We also provide a nostalgic look on recent advances in role of Wnts in T cell development and maturation. These reviews highlight the extensive body of work in these thematic areas as well as identify knowledge gaps, where appropriate. Understanding Wnt function under healthy and diseased conditions may provide a therapeutic resource, albeit it a challenging one, in diseases where dysfunctional and/or diminished Wnt signaling is a prominent player in the disease process.

  7. 经典Wnt信号通路在牙齿发育中的研究新进展%Recent advances About Canonical Wnt Pathway in Tooth Development

    Institute of Scientific and Technical Information of China (English)

    王也; 李汉梁; 林丽娣; 林鑫; 王冰梅

    2011-01-01

    Canonical Wnt signaling pathway is one of the main four categories of signal transduction pathway involving in embrvo and organ development. It also plays an important role in the tooth development. In this paper, we briefly write an overview about the new research of β -catenin,Lefl,Apc,Axin2 in tooth development: β -catenin affects the interaction between epithelium and mesenchyme by regulating other signals; the LEF/TCF complex can regulate the fate of dental epithelium cell; Apc inhibits supernumerary tooth formation during embryo genesis; and Axin2 has the influence of development of the crown and root during pre- and postnatal tooth development. So here we hope it may bring a new breakthrough among tooth regeneration and other bioengineerings.%经典Wnt信号通路是参与胚胎及器官发育的四大信号传导途径之一,在牙齿发育中扮演了重要的角色.本文对其中的β-catenin,Lefl,Apc,Axin2这4个关键因子在牙齿发育中研究的新进展做了简要的概述:β-catenin在间充质中会调控多个信号,影响牙上皮和间充质相互作用;Lefl会和Tcf家族一道调控上皮细胞命运;Apc能抑制多余牙齿的形成;Axin2在牙晚期发育中影响牙本质的形成.通过这些因子的研究,希望人们能在牙齿再生等生物医学工程上有新的突破.

  8. Wnt/β-catenin Signaling in Normal and Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Kenneth C. Valkenburg

    2011-04-01

    Full Text Available The ability of Wnt ligands to initiate a signaling cascade that results in cytoplasmic stabilization of, and nuclear localization of, β-catenin underlies their ability to regulate progenitor cell differentiation. In this review, we will summarize the current knowledge of the mechanisms underlying Wnt/β-catenin signaling and how the pathway regulates normal differentiation of stem cells in the intestine, mammary gland, and prostate. We will also discuss how dysregulation of the pathway is associated with putative cancer stem cells and the potential therapeutic implications of regulating Wnt signaling.

  9. Curcumin Rescues Diabetic Renal Fibrosis by Targeting Superoxide-Mediated Wnt Signaling Pathways.

    Science.gov (United States)

    Ho, Cheng; Hsu, Yung-Chien; Lei, Chen-Chou; Mau, Shu-Ching; Shih, Ya-Hsueh; Lin, Chun-Liang

    2016-03-01

    The purposes of this study were to investigate whether curcumin can weaken diabetic nephropathy by modulating both oxidative stress and renal injury from Wnt signaling mediation. Wnt5a/β-catenin depression and induction of superoxide synthesis are associated with high glucose (HG) induced transforming growth factor (TGF)-β1 and fibronectin expression in mesangial cells. Curcumin resumes HG depression of Wnt/β-catenin signaling and alleviates HG induction of superoxide, TGF-β1 and fibronectin expression in renal mesangial cell. Exogenous curcumin alleviated urinary total proteinuria and serum superoxide level in diabetic rats. Based on laser-captured microdissection for quantitative real-time polymerase chain reaction, it was found that diabetes significantly increased TGF-β1 and fibronectin expression in line with depressed Wnt5a expression. Curcumin treatment reduced the TGF-β1 and fibronectin activation and the inhibiting effect of diabetes on Wnt5a/β-catenin expression in renal glomeruli. Immunohistochemistry showed that curcumin treatment significantly reduced 8-hydroxy-2'-deoxyguanosine, TGF-β1 and fibronectin, and was in line with the restoration of the suppressed Wnt5a expression immunoreactivities in glomeruli of diabetic rats. Curcumin alleviated extracellular matrix accumulation in diabetic nephropathy by not only preventing the diabetes-mediated superoxide synthesis but also resuming downregulation of Wnt/β-catenin signaling. These findings suggest that regulation of Wnt activity by curcumin is a feasible alternative strategy to rescue diabetic renal injury.

  10. Genomic insights into Wnt signaling in an early diverging metazoan, the ctenophore Mnemiopsis leidyi

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    Pang Kevin

    2010-10-01

    Full Text Available Abstract Background Intercellular signaling pathways are a fundamental component of the integrating cellular behavior required for the evolution of multicellularity. The genomes of three of the four early branching animal phyla (Cnidaria, Placozoa and Porifera have been surveyed for key components, but not the fourth (Ctenophora. Genomic data from ctenophores could be particularly relevant, as ctenophores have been proposed to be one of the earliest branching metazoan phyla. Results A preliminary assembly of the lobate ctenophore Mnemiopsis leidyi genome generated using next-generation sequencing technologies were searched for components of a developmentally important signaling pathway, the Wnt/β-catenin pathway. Molecular phylogenetic analysis shows four distinct Wnt ligands (MlWnt6, MlWnt9, MlWntA and MlWntX, and most, but not all components of the receptor and intracellular signaling pathway were detected. In situ hybridization of the four Wnt ligands showed that they are expressed in discrete regions associated with the aboral pole, tentacle apparati and apical organ. Conclusions Ctenophores show a minimal (but not obviously simple complement of Wnt signaling components. Furthermore, it is difficult to compare the Mnemiopsis Wnt expression patterns with those of other metazoans. mRNA expression of Wnt pathway components appears later in development than expected, and zygotic gene expression does not appear to play a role in early axis specification. Notably absent in the Mnemiopsis genome are most major secreted antagonists, which suggests that complex regulation of this secreted signaling pathway probably evolved later in animal evolution.

  11. Epigenetic alterations of the Wnt signaling pathway in cancer: a mini review

    Directory of Open Access Journals (Sweden)

    Ljiljana Serman

    2014-11-01

    Full Text Available Epigenetic mechanisms play a crucial role in cellular proliferation, migration and differentiation in both normal and neoplastic development. One of the key signaling pathways whose components are altered through the epigenetic mechanisms is the Wnt signaling pathway. In this review, we briefly discuss the key concepts of epigenetics and focus on the recent advances in the Wnt signaling pathway research and its potential diagnostic and therapeutic implications.

  12. Stem cell signaling. An integral program for tissue renewal and regeneration : Wnt signaling and stem cell control

    NARCIS (Netherlands)

    Clevers, Hans; Loh, Kyle M; Nusse, Roel

    2014-01-01

    Stem cells fuel tissue development, renewal, and regeneration, and these activities are controlled by the local stem cell microenvironment, the "niche." Wnt signals emanating from the niche can act as self-renewal factors for stem cells in multiple mammalian tissues. Wnt proteins are lipid-modified,

  13. Wnt signaling in neuropsychiatric disorders: ties with adult hippocampal neurogenesis and behavior

    Science.gov (United States)

    Hussaini, Syed Mohammed Qasim; Choi, Chan-Il; Cho, Chang Hoon; Kim, Hyo Jin; Jun, Heechul; Jang, Mi-Hyeon

    2014-01-01

    In an effort to better understand and treat mental disorders, the Wnt pathway and adult hippocampal neurogenesis have received increased attention in recent years. One is a signaling pathway regulating key aspects of embryonic patterning, cell specification, and adult tissue homeostasis. The other is the generation of newborn neurons in adulthood that integrate into the neural circuit and function in learning and memory, and mood behavior. In this review, we discuss the growing relationship between Wnt signaling-mediated regulation of adult hippocampal neurogenesis as it applies to neuropsychiatric disorders. Evidence suggests dysfunctional Wnt signaling may aberrantly regulate new neuron development and cognitive function. Indeed, altered expression of key Wnt pathway components are observed in the hippocampus of patients suffering from neuropsychiatric disorders. Clinically-utilized mood stabilizers also proceed through modulation of Wnt signaling in the hippocampus, while Wnt pathway antagonists can regulate the antidepressant response. Here, we review the role of Wnt signaling in disease etiology and pathogenesis, regulation of adult neurogenesis and behavior, and the therapeutic targeting of disease symptoms. PMID:25263701

  14. Inhibition of Wnt/β-catenin signaling by a soluble collagen-derived frizzled domain interacting with Wnt3a and the receptors frizzled 1 and 8.

    Directory of Open Access Journals (Sweden)

    Ismaïl Hendaoui

    Full Text Available The Wnt/β-catenin pathway controls cell proliferation, death and differentiation. Several families of extracellular proteins can antagonize Wnt/β-catenin signaling, including the decoy receptors known as secreted frizzled related proteins (SFRPs, which have a cysteine-rich domain (CRD structurally similar to the extracellular Wnt-binding domain of the frizzled receptors. SFRPs inhibit Wnt signaling by sequestering Wnts through the CRD or by forming inactive complexes with the frizzled receptors. Other endogenous molecules carrying frizzled CRDs inhibit Wnt signaling, such as V3Nter, which is proteolytically derived from the cell surface component collagen XVIII and contains a biologically active frizzled domain (FZC18 inhibiting in vivo cell proliferation and tumor growth in mice. We recently showed that FZC18 expressing cells deliver short-range signals to neighboring cells, decreasing their proliferation in vitro and in vivo through the Wnt/β-catenin signaling pathway. Here, using low concentrations of soluble FZC18 and Wnt3a, we show that they physically interact in a cell-free system. In addition, soluble FZC18 binds the frizzled 1 and 8 receptors' CRDs, reducing cell sensitivity to Wnt3a. Conversely, inhibition of Wnt/β-catenin signaling was partially rescued by the expression of full-length frizzled 1 and 8 receptors, but enhanced by the expression of a chimeric cell-membrane-tethered frizzled 8 CRD. Moreover, soluble, partially purified recombinant FZC18_CRD inhibited Wnt3a-induced β-catenin activation. Taken together, the data indicate that collagen XVIII-derived frizzled CRD shifts Wnt sensitivity of normal cells to a lower pitch and controls their growth.

  15. Age-related neuroinflammation and changes in AKT-GSK-3β and WNT/ β-CATENIN signaling in rat hippocampus.

    Science.gov (United States)

    Orellana, Ana Maria Marques; Vasconcelos, Andrea Rodrigues; Leite, Jacqueline Alves; de Sá Lima, Larissa; Andreotti, Diana Zukas; Munhoz, Carolina Demarchi; Kawamoto, Elisa Mitiko; Scavone, Cristoforo

    2015-12-01

    Aging is a multifactorial process associated with an increased susceptibility to neurodegenerative disorders which can be related to chronic inflammation. Chronic inflammation, however, can be characterized by the persistent elevated glucocorticoid (GCs) levels, activation of the proinflammatory transcription factor NF-кB, as well as an increase in cytokines. Interestingly, both NF-кB and cytokines can be even modulated by Glycogen Synthase Kinase 3 beta (GSK-3β) activity, which is a key protein that can intermediate inflammation and metabolism, once it has a critical role in AKT signaling pathway, and can also intermediate WNT/β-CATENIN signaling pathway. The aim of this study was to verify age-related changes in inflammatory status, as well as in the AKT and WNT signaling pathways. Results showed an age-related increase in neuroinflammation as indicated by NF-кB activation, TNF-α and GCs increased levels, a decrease in AKT activation and an increase in GSK-3β activity in both 12- and 24- month old animals. Aging also seems to induce a progressive decrease in canonical WNT/β-CATENIN signaling pathway once there is a decrease in DVL-2 levels and in the transcription of Axin2 gene. Little is known about the DVL-2 regulation as well as its roles in WNT signaling pathway, but for the first time it was suggested that DVL-2 expression can be changed along aging.

  16. miR-577 inhibits glioblastoma tumor growth via the Wnt signaling pathway.

    Science.gov (United States)

    Zhang, Weiguang; Shen, Chen; Li, Chenguang; Yang, Guang; Liu, Huailei; Chen, Xin; Zhu, Dan; Zou, Huichao; Zhen, Yunbo; Zhang, Daming; Zhao, Shiguang

    2016-05-01

    microRNAs (miRNAs) are commonly altered in glioblastoma. Publicly available algorithms suggest the Wnt pathway is a potential target of miR-577 and the Wnt pathway is commonly altered in glioblastoma. Glioblastoma has not been previously evaluated for miR-577 expression. Glioblastoma tumors and cell lines were evaluated for their expression of miR-577. Cell lines were transfected with miR-577, miR-577-mutant, or control mimics to evaluate the effect of miR-577 expression on cell proliferation in vitro and in an animal model. Wnt pathway markers were also evaluated for their association with miR-577 expression. miR-577 expression was decreased in 33 of 40 (82.5%) glioblastoma tumors and 5 of 6 glioblastoma cell lines. miR-577 expression correlated negatively with cell growth and cell viability. miR-577 down-regulation was associated with increased expression of the Wnt signaling pathway genes lipoprotein receptor-related protein (LRP) 6 (LRP6) and β-catenin. Western blot analysis confirmed decreased expression of the Wnt signaling pathway genes Axin2, c-myc, and cyclin D1 in miR-577 transfected cells. miR-577 expression is down-regulated in glioblastoma. miR-577 directly targets Wnt signaling pathway components LRP6 and β-catenin. miR-577 suppresses glioblastoma multiforme (GBM) growth by regulating the Wnt signaling pathway.

  17. Inhibition of Wnt signalling and breast tumour growth by the multi-purpose drug suramin through suppression of heterotrimeric G proteins and Wnt endocytosis.

    Science.gov (United States)

    Koval, Alexey; Ahmed, Kamal; Katanaev, Vladimir L

    2016-02-15

    Overactivation of the Wnt signalling pathway underlies oncogenic transformation and proliferation in many cancers, including the triple-negative breast cancer (TNBC), the deadliest form of tumour in the breast, taking about a quarter of a million lives annually worldwide. No clinically approved targeted therapies attacking Wnt signalling currently exist. Repositioning of approved drugs is a promising approach in drug discovery. In the present study we show that a multi-purpose drug suramin inhibits Wnt signalling and proliferation of TNBC cells in vitro and in mouse models, inhibiting a component in the upper levels of the pathway. Through a set of investigations we identify heterotrimeric G proteins and regulation of Wnt endocytosis as the likely target of suramin in this pathway. G protein-dependent endocytosis of plasma membrane-located components of the Wnt pathway was previously shown to be important for amplification of the signal in this cascade. Our data identify endocytic regulation within Wnt signalling as a promising target for anti-Wnt and anti-cancer drug discovery. Suramin, as the first example of such drug or its analogues might pave the way for the appearance of first-in-class targeted therapies against TNBC and other Wnt-dependent cancers.

  18. Wnt-3A/beta-catenin signaling induces transcription from the LEF-1 promoter.

    Science.gov (United States)

    Filali, Mohammed; Cheng, Ningli; Abbott, Duane; Leontiev, Vladimir; Engelhardt, John F

    2002-09-06

    Members of the Wnt family of secreted molecules have been established as key factors in determining cell fate and morphogenic signaling. It has long been recognized that Wnt induces morphogenic signaling through the Tcf/LEF-1 cascade by regulating free intracellular levels of beta-catenin, a co-factor for Tcf/LEF-1 transcription factors. In the present study, we have demonstrated that Wnt-3A can also directly induce transcription from the LEF-1 promoter. This induction was dependent on glycogen synthase kinase 3beta inactivation, a rise in free intracellular beta-catenin, and a short 110-bp Wnt-responsive element (WRE) in the LEF-1 promoter. Linear and internal deletion of this WRE led to a dramatic increase in constitutive LEF-1 promoter activity and loss of Wnt-3A responsiveness. In isolation, the 110-bp WRE conferred context-independent Wnt-3A or beta-catenin(S37A) responsiveness to a heterologous SV40 promoter. Studies expressing dominant active and negative forms of LEF-1, beta-catenin, GSK-3beta, and beta-catenin/LEF-1 fusions suggest that Wnt-3A activates the LEF-1 promoter through a beta-catenin-dependent and LEF-1-independent process. Wnt-3A expression also induced multiple changes in the binding of factors to the WRE and suggests that regulatory mechanisms may involve modulation of a multiprotein complex. In summary, these results provide evidence for transcriptional regulation of the LEF-1 promoter by Wnt and enhance the mechanistic understanding of Wnt/beta-catenin signaling in the regulation of LEF-1-dependent developmental processes.

  19. WNT5A inhibits hepatocyte proliferation and concludes β-catenin signaling in liver regeneration.

    Science.gov (United States)

    Yang, Jing; Cusimano, Antonella; Monga, Jappmann K; Preziosi, Morgan E; Pullara, Filippo; Calero, Guillermo; Lang, Richard; Yamaguchi, Terry P; Nejak-Bowen, Kari N; Monga, Satdarshan P

    2015-08-01

    Activation of Wnt/β-catenin signaling during liver regeneration (LR) after partial hepatectomy (PH) is observed in several species. However, how this pathway is turned off when hepatocyte proliferation is no longer required is unknown. We assessed LR in liver-specific knockouts of Wntless (Wls-LKO), a protein required for Wnt secretion from a cell. When subjected to PH, Wls-LKO showed prolongation of hepatocyte proliferation for up to 4 days compared with littermate controls. This coincided with increased β-catenin-T-cell factor 4 interaction and cyclin-D1 expression. Wls-LKO showed decreased expression and secretion of inhibitory Wnt5a during LR. Wnt5a expression increased between 24 and 48 hours, and Frizzled-2 between 24 and 72 hours, after PH in normal mice. Treatment of primary mouse hepatocytes and liver tumor cells with Wnt5a led to a notable decrease in β-catenin-T-cell factor activity, cyclin-D1 expression, and cell proliferation. Intriguingly, Wnt5a-LKO did not display any prolongation of LR because of compensation by other cells. In addition, Wnt5a-LKO hepatocytes failed to respond to exogenous Wnt5a treatment in culture because of a compensatory decrease in Frizzled-2 expression. In conclusion, we demonstrate Wnt5a to be, by default, a negative regulator of β-catenin signaling and hepatocyte proliferation, both in vitro and in vivo. We also provide evidence that the Wnt5a/Frizzled-2 axis suppresses β-catenin signaling in hepatocytes in an autocrine manner, thereby contributing to timely conclusion of the LR process.

  20. Understanding and Targeting the Wnt/β-Catenin Signaling Pathway in Chronic Leukemia

    Directory of Open Access Journals (Sweden)

    S. Thanendrarajan

    2011-01-01

    Full Text Available It has been revealed that the Wnt/β-catenin signaling pathway plays an important role in the development of solid tumors and hematological malignancies, particularly in B-cell neoplasia and leukemia. In the last decade there have been made experimental approaches targeting the Wnt pathway in chronic leukemia. In this paper we provide an overview about the current state of knowledge regarding the Wnt/β-catenin signaling pathway in chronic leukemia with special focus on therapeutic options and strategies.

  1. Experimental inhibition of porcupine-mediated Wnt O-acylation attenuates kidney fibrosis.

    Science.gov (United States)

    Madan, Babita; Patel, Mehul B; Zhang, Jiandong; Bunte, Ralph M; Rudemiller, Nathan P; Griffiths, Robert; Virshup, David M; Crowley, Steven D

    2016-05-01

    Activated Wnt signaling is critical in the pathogenesis of renal fibrosis, a final common pathway for most forms of chronic kidney disease. Therapeutic intervention by inhibition of individual Wnts or downstream Wnt/β-catenin signaling has been proposed, but these approaches do not interrupt the functions of all Wnts nor block non-canonical Wnt signaling pathways. Alternatively, an orally bioavailable small molecule, Wnt-C59, blocks the catalytic activity of the Wnt-acyl transferase porcupine, and thereby prevents secretion of all Wnt isoforms. We found that inhibiting porcupine dramatically attenuates kidney fibrosis in the murine unilateral ureteral obstruction model. Wnt-C59 treatment similarly blunts collagen mRNA expression in the obstructed kidney. Consistent with its actions to broadly arrest Wnt signaling, porcupine inhibition reduces expression of Wnt target genes and bolsters nuclear exclusion of β-catenin in the kidney following ureteral obstruction. Importantly, prevention of Wnt secretion by Wnt-C59 blunts expression of inflammatory cytokines in the obstructed kidney that otherwise provoke a positive feedback loop of Wnt expression in collagen-producing fibroblasts and epithelial cells. Thus, therapeutic targeting of porcupine abrogates kidney fibrosis not only by overcoming the redundancy of individual Wnt isoforms but also by preventing upstream cytokine-induced Wnt generation. These findings reveal a novel therapeutic maneuver to protect the kidney from fibrosis by interrupting a pathogenic crosstalk loop between locally generated inflammatory cytokines and the Wnt/β-catenin signaling pathway.

  2. Increased glutamine catabolism mediates bone anabolism in response to WNT signaling.

    Science.gov (United States)

    Karner, Courtney M; Esen, Emel; Okunade, Adewole L; Patterson, Bruce W; Long, Fanxin

    2015-02-01

    WNT signaling stimulates bone formation by increasing both the number of osteoblasts and their protein-synthesis activity. It is not clear how WNT augments the capacity of osteoblast progenitors to meet the increased energetic and synthetic needs associated with mature osteoblasts. Here, in cultured osteoblast progenitors, we determined that WNT stimulates glutamine catabolism through the tricarboxylic acid (TCA) cycle and consequently lowers intracellular glutamine levels. The WNT-induced reduction of glutamine concentration triggered a general control nonderepressible 2-mediated (GCN2-mediated) integrated stress response (ISR) that stimulated expression of genes responsible for amino acid supply, transfer RNA (tRNA) aminoacylation, and protein folding. WNT-induced glutamine catabolism and ISR were β-catenin independent, but required mammalian target of rapamycin complex 1 (mTORC1) activation. In a hyperactive WNT signaling mouse model of human osteosclerosis, inhibition of glutamine catabolism or Gcn2 deletion suppressed excessive bone formation. Together, our data indicate that glutamine is both an energy source and a protein-translation rheostat that is responsive to WNT and suggest that manipulation of the glutamine/GCN2 signaling axis may provide a valuable approach for normalizing deranged protein anabolism associated with human diseases.

  3. Trans-synaptic transmission of vesicular Wnt signals through Evi/Wntless.

    Science.gov (United States)

    Korkut, Ceren; Ataman, Bulent; Ramachandran, Preethi; Ashley, James; Barria, Romina; Gherbesi, Norberto; Budnik, Vivian

    2009-10-16

    Wnts play pivotal roles during development and in the mature nervous system. However, the mechanism by which Wnts traffic between cells has remained elusive. Here we demonstrate a mechanism of Wnt transmission through release of exosome-like vesicles containing the Wnt-binding protein Evenness Interrupted/Wntless/Sprinter (Evi/Wls/Srt). We show that at the Drosophila larval neuromuscular junction (NMJ), presynaptic vesicular release of Evi is required for the secretion of the Wnt, Wingless (Wg). We also show that Evi acts cell-autonomously in the postsynaptic Wnt-receiving cell to target dGRIP, a Wg-receptor-interacting protein, to postsynaptic sites. Upon Evi loss of function, dGRIP is not properly targeted to synaptic sites, interfering with postsynaptic Wnt signal transduction. These findings uncover a previously unknown cellular mechanism by which a secreted Wnt is transported across synapses by Evi-containing vesicles and reveal trafficking functions of Evi in both the Wnt-producing and the Wnt-receiving cells. For a video summary of this article, see the PaperFlick file with the Supplemental Data available online.

  4. LRP4 mutations alter Wnt/beta-catenin signaling and cause limb and kidney malformations in Cenani-Lenz syndrome.

    Science.gov (United States)

    Li, Yun; Pawlik, Barbara; Elcioglu, Nursel; Aglan, Mona; Kayserili, Hülya; Yigit, Gökhan; Percin, Ferda; Goodman, Frances; Nürnberg, Gudrun; Cenani, Asim; Urquhart, Jill; Chung, Boi-Dinh; Ismail, Samira; Amr, Khalda; Aslanger, Ayca D; Becker, Christian; Netzer, Christian; Scambler, Pete; Eyaid, Wafaa; Hamamy, Hanan; Clayton-Smith, Jill; Hennekam, Raoul; Nürnberg, Peter; Herz, Joachim; Temtamy, Samia A; Wollnik, Bernd

    2010-05-14

    Cenani-Lenz syndrome (CLS) is an autosomal-recessive congenital disorder affecting distal limb development. It is characterized mainly by syndactyly and/or oligodactyly and is now shown to be commonly associated with kidney anomalies. We used a homozygosity-mapping approach to map the CLS1 locus to chromosome 11p11.2-q13.1. By sequencing candidate genes, we identified recessive LRP4 mutations in 12 families with CLS. LRP4 belongs to the low-density lipoprotein (LDL) receptor-related proteins (LRPs), which are essential for various developmental processes. LRP4 is known to antagonize LRP6-mediated activation of canonical Wnt signaling, a function that is lost by the identified mutations. Our findings increase the spectrum of congenital anomalies associated with abnormal lipoprotein receptor-dependent signaling.

  5. Wls promotes the proliferation of breast cancer cells via Wnt signaling.

    Science.gov (United States)

    Lu, Dong; Li, Ying; Liu, Qing-Ru; Wu, Qi; Zhang, Hao; Xie, Peng; Wang, Qingling

    2015-05-01

    The Wnt secretion protein Wntless (Wls)/GPR177 has been reported to be involved in the development of several human cancers. However, the biological significance of Wls in breast cancer progression has not been clarified. In this study, we show for the first time that Wls is an important molecule related to breast cancer. We find that Wls expression is markedly increased in clinical breast tumors compared with adjacent noncancerous tissues. Downregulation of Wls by short-hairpin RNA severely suppressed the proliferation of breast cancer cells. Wls is a core Wnt signaling component, and we show that knockdown of Wls is sufficient to inhibit Wnt secretion and its downstream signaling. Taken together, these results indicate that Wls contributes to the proliferation of breast cancer cells by regulating Wnt signaling. Therefore, Wls could be a novel therapeutic target for inhibiting cell growth in breast cancer.

  6. Interfollicular epidermal stem cells self-renew via autocrine Wnt signaling.

    Science.gov (United States)

    Lim, Xinhong; Tan, Si Hui; Koh, Winston Lian Chye; Chau, Rosanna Man Wah; Yan, Kelley S; Kuo, Calvin J; van Amerongen, Renée; Klein, Allon Moshe; Nusse, Roel

    2013-12-06

    The skin is a classical example of a tissue maintained by stem cells. However, the identity of the stem cells that maintain the interfollicular epidermis and the source of the signals that control their activity remain unclear. Using mouse lineage tracing and quantitative clonal analyses, we showed that the Wnt target gene Axin2 marks interfollicular epidermal stem cells. These Axin2-expressing cells constitute the majority of the basal epidermal layer, compete neutrally, and require Wnt/β-catenin signaling to proliferate. The same cells contribute robustly to wound healing, with no requirement for a quiescent stem cell subpopulation. By means of double-labeling RNA in situ hybridization in mice, we showed that the Axin2-expressing cells themselves produce Wnt signals as well as long-range secreted Wnt inhibitors, suggesting an autocrine mechanism of stem cell self-renewal.

  7. The emerging role of Wnt/PCP signaling in organ formation.

    Science.gov (United States)

    Dale, Rodney M; Sisson, Barbara E; Topczewski, Jacek

    2009-03-01

    Over the last two decades zebrafish has been an excellent model organism to study vertebrate development. Mutant analysis combined with gene knockdown and other manipulations revealed an essential role of Wnt signaling, independent of beta-catenin, during development. Especially well characterized is the function of Wnt/planar cell polarity (PCP) signaling in the regulation of gastrulation movements and neurulation, described in other reviews within this special issue. Here, we set out to highlight some of the new and exciting research that is being carried out in zebrafish to elucidate the role that Wnt/PCP signaling plays in the formation of specific organs, including the lateral line, craniofacial development, and regeneration. We also summarized the emerging connection of the Wnt/PCP pathway with primary cilia function, an essential organelle in several organ activities.

  8. EdnrB Governs Regenerative Response of Melanocyte Stem Cells by Crosstalk with Wnt Signaling.

    Science.gov (United States)

    Takeo, Makoto; Lee, Wendy; Rabbani, Piul; Sun, Qi; Hu, Hai; Lim, Chae Ho; Manga, Prashiela; Ito, Mayumi

    2016-05-10

    Delineating the crosstalk between distinct signaling pathways is key to understanding the diverse and dynamic responses of adult stem cells during tissue regeneration. Here, we demonstrate that the Edn/EdnrB signaling pathway can interact with other signaling pathways to elicit distinct stem cell functions during tissue regeneration. EdnrB signaling promotes proliferation and differentiation of melanocyte stem cells (McSCs), dramatically enhancing the regeneration of hair and epidermal melanocytes. This effect is dependent upon active Wnt signaling that is initiated by Wnt ligand secretion from the hair follicle epithelial niche. Further, this Wnt-dependent EdnrB signaling can rescue the defects in melanocyte regeneration caused by Mc1R loss. This suggests that targeting Edn/EdnrB signaling in McSCs can be a therapeutic approach to promote photoprotective-melanocyte regeneration, which may be useful for those with increased risk of skin cancers due to Mc1R variants.

  9. EdnrB Governs Regenerative Response of Melanocyte Stem Cells by Crosstalk with Wnt Signaling

    Directory of Open Access Journals (Sweden)

    Makoto Takeo

    2016-05-01

    Full Text Available Delineating the crosstalk between distinct signaling pathways is key to understanding the diverse and dynamic responses of adult stem cells during tissue regeneration. Here, we demonstrate that the Edn/EdnrB signaling pathway can interact with other signaling pathways to elicit distinct stem cell functions during tissue regeneration. EdnrB signaling promotes proliferation and differentiation of melanocyte stem cells (McSCs, dramatically enhancing the regeneration of hair and epidermal melanocytes. This effect is dependent upon active Wnt signaling that is initiated by Wnt ligand secretion from the hair follicle epithelial niche. Further, this Wnt-dependent EdnrB signaling can rescue the defects in melanocyte regeneration caused by Mc1R loss. This suggests that targeting Edn/EdnrB signaling in McSCs can be a therapeutic approach to promote photoprotective-melanocyte regeneration, which may be useful for those with increased risk of skin cancers due to Mc1R variants.

  10. Pomegranate Bioactive Constituents Suppress Cell Proliferation and Induce Apoptosis in an Experimental Model of Hepatocellular Carcinoma: Role of Wnt/β-Catenin Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Deepak Bhatia

    2013-01-01

    Full Text Available Hepatocellular carcinoma (HCC is the third leading cause of cancer-related death worldwide, and chemoprevention represents a viable approach in lowering the mortality of this disease. Pomegranate fruit, an abundant source of anti-inflammatory phytochemicals, is gaining tremendous attention for its wide-spectrum health benefits. We previously reported that a characterized pomegranate emulsion (PE prevents diethylnitrosamine (DENA-induced rat hepatocarcinogenesis though inhibition of nuclear factor-kappaB (NF-κB. Since NF-κB concurrently induces Wnt/β-catenin signaling implicated in cell proliferation, cell survival, and apoptosis evasion, we examined antiproliferative, apoptosis-inducing and Wnt/β-catenin signaling-modulatory mechanisms of PE during DENA rat hepatocarcinogenesis. PE (1 or 10 g/kg was administered 4 weeks before and 18 weeks following DENA exposure. There was a significant increase in hepatic proliferation (proliferating cell nuclear antigen and alteration in cell cycle progression (cyclin D1 due to DENA treatment, and PE dose dependently reversed these effects. PE substantially induced apoptosis by upregulating proapoptotic protein Bax and downregulating antiapoptotic protein Bcl-2. PE dose dependently reduced hepatic β-catenin and augmented glycogen synthase kinase-3β expression. Our study provides evidence that pomegranate phytochemicals exert chemoprevention of hepatic cancer through antiproliferative and proapoptotic mechanisms by modulating Wnt/β-catenin signaling. PE, thus, targets two interconnected molecular circuits (canonical NF-κB and Wnt/β-catenin pathways to exert chemoprevention of HCC.

  11. Electric signals regulate directional migration of ventral midbrain derived dopaminergic neural progenitor cells via Wnt/GSK3β signaling.

    Science.gov (United States)

    Liu, Jia; Zhu, Bangfu; Zhang, Gaofeng; Wang, Jian; Tian, Weiming; Ju, Gong; Wei, Xiaoqing; Song, Bing

    2015-01-01

    Neural progenitor cell (NPC) replacement therapy is a promising treatment for neurodegenerative disorders including Parkinson's disease (PD). It requires a controlled directional migration and integration of NPCs, for example dopaminergic (DA) progenitor cells, into the damaged host brain tissue. There is, however, only limited understanding of how to regulate the directed migration of NPCs to the diseased or damaged brain tissues for repair and regeneration. The aims of this study are to explore the possibility of using a physiological level of electrical stimulation to regulate the directed migration of ventral midbrain NPCs (NPCs(vm)), and to investigate their potential regulation via GSK3β and associated downstream effectors. We tested the effects of direct-current (DC) electric fields (EFs) on the migration behavior of the NPCs(vm). A DC EF induced directional cell migration toward the cathode, namely electrotaxis. Reversal of the EF polarity triggered a sharp reversal of the NPC(vm) electrotaxis. The electrotactic response was both time and EF voltage dependent. Pharmacologically inhibiting the canonical Wnt/GSK3β pathway significantly reduced the electrotactic response of NPCs(vm), which is associated with the down-regulation of GSK3β phosphorylation, β-catenin activation and CLASP2 expression. This was further proved by RNA interference of GSK3β, which also showed a significantly reduced electrotactic response in association with reduced β-catenin activation and CLASP2 expression. In comparison, RNA interference of β-catenin slightly reduced electrotactic response and CLASP2 expression. Both pharmacological inhibition of Wnt/GSK3β and RNA interference of GSK3β/β-catenin clearly reduced the asymmetric redistribution of CLASP2 and its co-localization with α-tubulin. These results suggest that Wnt/GSK3β signaling contributes to the electrotactic response of NPCs(vm) through the coordination of GSK3β phosphorylation, β-catenin activation, CLASP2

  12. Activation of Wnt/β-catenin signaling increases apoptosis in melanoma cells treated with trail.

    Directory of Open Access Journals (Sweden)

    Zachary F Zimmerman

    Full Text Available While the TRAIL pathway represents a promising therapeutic target in melanoma, resistance to TRAIL-mediated apoptosis remains a barrier to its successful adoption. Since the Wnt/β-catenin pathway has been implicated in facilitating melanoma cell apoptosis, we investigated the effect of Wnt/β-catenin signaling on regulating the responses of melanoma cells to TRAIL. Co-treatment of melanoma cell lines with WNT3A-conditioned media and recombinant TRAIL significantly enhanced apoptosis compared to treatment with TRAIL alone. This apoptosis correlates with increased abundance of the pro-apoptotic proteins BCL2L11 and BBC3, and with decreased abundance of the anti-apoptotic regulator Mcl1. We then confirmed the involvement of the Wnt/β-catenin signaling pathway by demonstrating that siRNA-mediated knockdown of an intracellular β-catenin antagonist, AXIN1, or treating cells with an inhibitor of GSK-3 also enhanced melanoma cell sensitivity to TRAIL. These studies describe a novel regulation of TRAIL sensitivity in melanoma by Wnt/β-catenin signaling, and suggest that strategies to enhance Wnt/β-catenin signaling in combination with TRAIL agonists warrant further investigation.

  13. Variation in the Kozak sequence of WNT16 results in an increased translation and is associated with osteoporosis related parameters

    DEFF Research Database (Denmark)

    Hendrickx, Gretl; Boudin, Eveline; Fijałkowski, Igor

    2014-01-01

    population. The observed effect of these three associated SNPs on the respective phenotypes is comparable and we can conclude that the presence of the minor allele results in an increase in BMD. Additionally, we performed re-sequencing of WNT16 on two cohorts selected from the young OAS cohort, based...... on their extreme BMD values. On this basis, rs55710688 was selected for an in vitro translation experiment since it is located in the Kozak sequence of WNT16a. We observed an increased translation efficiency and thus a higher amount of WNT16a for the Kozak sequence that was significantly more prevalent in the high...... WNT pathway. Increased translation of WNT16 can thus lead to an increased inhibitory action of WNT16 on canonical WNT signaling. This statement is in contrast with the known activating effect of canonical WNT signaling on bone formation and suggests a stimulatory effect on bone metabolism via...

  14. Genome-wide analysis of a Wnt1-regulated transcriptional network implicates neurodegenerative pathways.

    Science.gov (United States)

    Wexler, Eric M; Rosen, Ezra; Lu, Daning; Osborn, Gregory E; Martin, Elizabeth; Raybould, Helen; Geschwind, Daniel H

    2011-10-04

    Wnt proteins are critical to mammalian brain development and function. The canonical Wnt signaling pathway involves the stabilization and nuclear translocation of β-catenin; however, Wnt also signals through alternative, noncanonical pathways. To gain a systems-level, genome-wide view of Wnt signaling, we analyzed Wnt1-stimulated changes in gene expression by transcriptional microarray analysis in cultured human neural progenitor (hNP) cells at multiple time points over a 72-hour time course. We observed a widespread oscillatory-like pattern of changes in gene expression, involving components of both the canonical and the noncanonical Wnt signaling pathways. A higher-order, systems-level analysis that combined independent component analysis, waveform analysis, and mutual information-based network construction revealed effects on pathways related to cell death and neurodegenerative disease. Wnt effectors were tightly clustered with presenilin1 (PSEN1) and granulin (GRN), which cause dominantly inherited forms of Alzheimer's disease and frontotemporal dementia (FTD), respectively. We further explored a potential link between Wnt1 and GRN and found that Wnt1 decreased GRN expression by hNPs. Conversely, GRN knockdown increased WNT1 expression, demonstrating that Wnt and GRN reciprocally regulate each other. Finally, we provided in vivo validation of the in vitro findings by analyzing gene expression data from individuals with FTD. These unbiased and genome-wide analyses provide evidence for a connection between Wnt signaling and the transcriptional regulation of neurodegenerative disease genes.

  15. Genomic response to Wnt signalling is highly context-dependent - Evidence from DNA microarray and chromatin immunoprecipitation screens of Wnt/TCF targets

    Energy Technology Data Exchange (ETDEWEB)

    Railo, Antti [Oulu Centre for Cell Matrix Research, Biocenter Oulu, Laboratory of Developmental Biology and Department of Medical Biochemistry and Molecular Biology, FIN-90014, University of Oulu, P. O. Box 5000 (Finland); Pajunen, Antti [Department of Biochemistry, University of Oulu (Finland); Itaeranta, Petri; Naillat, Florence; Vuoristo, Jussi; Kilpelaeinen, Pekka [Oulu Centre for Cell Matrix Research, Biocenter Oulu, Laboratory of Developmental Biology and Department of Medical Biochemistry and Molecular Biology, FIN-90014, University of Oulu, P. O. Box 5000 (Finland); Vainio, Seppo, E-mail: Seppo.Vainio@oulu.fi [Oulu Centre for Cell Matrix Research, Biocenter Oulu, Laboratory of Developmental Biology and Department of Medical Biochemistry and Molecular Biology, FIN-90014, University of Oulu, P. O. Box 5000 (Finland)

    2009-10-01

    Wnt proteins are important regulators of embryonic development, and dysregulated Wnt signalling is involved in the oncogenesis of several human cancers. Our knowledge of the downstream target genes is limited, however. We used a chromatin immunoprecipitation-based assay to isolate and characterize the actual gene segments through which Wnt-activatable transcription factors, TCFs, regulate transcription and an Affymetrix microarray analysis to study the global transcriptional response to the Wnt3a ligand. The anti-{beta}-catenin immunoprecipitation of DNA-protein complexes from mouse NIH3T3 fibroblasts expressing a fusion protein of {beta}-catenin and TCF7 resulted in the identification of 92 genes as putative TCF targets. GeneChip assays of gene expression performed on NIH3T3 cells and the rat pheochromocytoma cell line PC12 revealed 355 genes in NIH3T3 and 129 genes in the PC12 cells with marked changes in expression after Wnt3a stimulus. Only 2 Wnt-regulated genes were shared by both cell lines. Surprisingly, Disabled-2 was the only gene identified by the chromatin immunoprecipitation approach that displayed a marked change in expression in the GeneChip assay. Taken together, our approaches give an insight into the complex context-dependent nature of Wnt pathway transcriptional responses and identify Disabled-2 as a potential new direct target for Wnt signalling.

  16. Wnt/Fz signaling and the cytoskeleton: potential roles in tumorigenesis

    Institute of Scientific and Technical Information of China (English)

    Shih-Lei Lai; Andy J Chien; Randall T Moon

    2009-01-01

    Wnt/β-catenin regulates cellular functions related to tumor initiation and progression, cell proliferation, differ-entiation, survival, and adhesion. β-Catenin-independent Wnt pathways have been proposed to regulate cell polarity and migration, including metastasis, In this review, we discuss the possible roles of both β-catenin-dependent and -independent signaling pathways in tumor progression, with an emphasis on their regulation of Rho-family GTPases, cytoskeletal remodeling, and relationships with cell-cell adhesion and cilia/ciliogenesis.

  17. The Wnt receptor Ryk plays a role in mammalian planar cell polarity signaling.

    Science.gov (United States)

    Macheda, Maria L; Sun, Willy W; Kugathasan, Kumudhini; Hogan, Benjamin M; Bower, Neil I; Halford, Michael M; Zhang, You Fang; Jacques, Bonnie E; Lieschke, Graham J; Dabdoub, Alain; Stacker, Steven A

    2012-08-24

    Wnts are essential for a wide range of developmental processes, including cell growth, division, and differentiation. Some of these processes signal via the planar cell polarity (PCP) pathway, which is a β-catenin-independent Wnt signaling pathway. Previous studies have shown that Ryk, a member of the receptor tyrosine kinase family, can bind to Wnts. Ryk is required for normal axon guidance and neuronal differentiation during development. Here, we demonstrate that mammalian Ryk interacts with the Wnt/PCP pathway. In vitro analysis showed that the Wnt inhibitory factor domain of Ryk was necessary for Wnt binding. Detailed analysis of two vertebrate model organisms showed Ryk phenotypes consistent with PCP signaling. In zebrafish, gene knockdown using morpholinos revealed a genetic interaction between Ryk and Wnt11 during the PCP pathway-regulated process of embryo convergent extension. Ryk-deficient mouse embryos displayed disrupted polarity of stereociliary hair cells in the cochlea, a characteristic of disturbed PCP signaling. This PCP defect was also observed in mouse embryos that were double heterozygotes for Ryk and Looptail (containing a mutation in the core Wnt/PCP pathway gene Vangl2) but not in either of the single heterozygotes, suggesting a genetic interaction between Ryk and Vangl2. Co-immunoprecipitation studies demonstrated that RYK and VANGL2 proteins form a complex, whereas RYK also activated RhoA, a downstream effector of PCP signaling. Overall, our data suggest an important role for Ryk in Wnt/planar cell polarity signaling during vertebrate development via the Vangl2 signaling pathway, as demonstrated in the mouse cochlea.

  18. Bili inhibits Wnt/beta-catenin signaling by regulating the recruitment of axin to LRP6.

    Directory of Open Access Journals (Sweden)

    Lorna S Kategaya

    Full Text Available BACKGROUND: Insights into how the Frizzled/LRP6 receptor complex receives, transduces and terminates Wnt signals will enhance our understanding of the control of the Wnt/ss-catenin pathway. METHODOLOGY/PRINCIPAL FINDINGS: In pursuit of such insights, we performed a genome-wide RNAi screen in Drosophila cells expressing an activated form of LRP6 and a beta-catenin-responsive reporter. This screen resulted in the identification of Bili, a Band4.1-domain containing protein, as a negative regulator of Wnt/beta-catenin signaling. We found that the expression of Bili in Drosophila embryos and larval imaginal discs significantly overlaps with the expression of Wingless (Wg, the Drosophila Wnt ortholog, which is consistent with a potential function for Bili in the Wg pathway. We then tested the functions of Bili in both invertebrate and vertebrate animal model systems. Loss-of-function studies in Drosophila and zebrafish embryos, as well as human cultured cells, demonstrate that Bili is an evolutionarily conserved antagonist of Wnt/beta-catenin signaling. Mechanistically, we found that Bili exerts its antagonistic effects by inhibiting the recruitment of AXIN to LRP6 required during pathway activation. CONCLUSIONS: These studies identify Bili as an evolutionarily conserved negative regulator of the Wnt/beta-catenin pathway.

  19. Paracrine WNT5A Signaling Inhibits Expansion of Tumor-Initiating Cells.

    Science.gov (United States)

    Borcherding, Nicholas; Kusner, David; Kolb, Ryan; Xie, Qing; Li, Wei; Yuan, Fang; Velez, Gabriel; Askeland, Ryan; Weigel, Ronald J; Zhang, Weizhou

    2015-05-15

    It is not well understood how paracrine communication between basal and luminal cell populations in the mammary gland affects tumorigenesis. During ErbB2-induced mammary tumorigenesis, enriched mammary stem cells that represent a subpopulation of basal cells exhibit enhanced tumorigenic capacity compared with the corresponding luminal progenitors. Transcript profiling of tumors derived from basal and luminal tumor-initiating cells (TIC) revealed preferential loss of the noncanonical Wnt ligand WNT5A in basal TIC-derived tumors. Heterozygous loss of WNT5A was correlated with shorter survival of breast cancer patients. In a mouse model of ErbB2-induced breast cancer, Wnt5a heterozygosity promoted tumor multiplicity and pulmonary metastasis. As a TGFβ substrate, luminal cell-produced WNT5A induced a feed-forward loop to activate SMAD2 in a RYK and TGFβR1-dependent manner to limit the expansion of basal TIC in a paracrine fashion, a potential explanation for the suppressive effect of WNT5A in mammary tumorigenesis. Our results identify the WNT5A/RYK module as a spatial regulator of the TGFβ-SMAD signaling pathway in the context of mammary gland development and carcinogenesis, offering a new perspective on tumor suppression provided by basal-luminal cross-talk in normal mammary tissue.

  20. Concerted involvement of Cdx/Hox genes and Wnt signaling in morphogenesis of the caudal neural tube and cloacal derivatives from the posterior growth zone.

    Science.gov (United States)

    van de Ven, Cesca; Bialecka, Monika; Neijts, Roel; Young, Teddy; Rowland, Jennifer E; Stringer, Emma J; Van Rooijen, Carina; Meijlink, Frits; Nóvoa, Ana; Freund, Jean-Noel; Mallo, Moises; Beck, Felix; Deschamps, Jacqueline

    2011-08-01

    Decrease in Cdx dosage in an allelic series of mouse Cdx mutants leads to progressively more severe posterior vertebral defects. These defects are corrected by posterior gain of function of the Wnt effector Lef1. Precocious expression of Hox paralogous 13 genes also induces vertebral axis truncation by antagonizing Cdx function. We report here that the phenotypic similarity also applies to patterning of the caudal neural tube and uro-rectal tracts in Cdx and Wnt3a mutants, and in embryos precociously expressing Hox13 genes. Cdx2 inactivation after placentation leads to posterior defects, including incomplete uro-rectal septation. Compound mutants carrying one active Cdx2 allele in the Cdx4-null background (Cdx2/4), transgenic embryos precociously expressing Hox13 genes and a novel Wnt3a hypomorph mutant all manifest a comparable phenotype with similar uro-rectal defects. Phenotype and transcriptome analysis in early Cdx mutants, genetic rescue experiments and gene expression studies lead us to propose that Cdx transcription factors act via Wnt signaling during the laying down of uro-rectal mesoderm, and that they are operative in an early phase of these events, at the site of tissue progenitors in the posterior growth zone of the embryo. Cdx and Wnt mutations and premature Hox13 expression also cause similar neural dysmorphology, including ectopic neural structures that sometimes lead to neural tube splitting at caudal axial levels. These findings involve the Cdx genes, canonical Wnt signaling and the temporal control of posterior Hox gene expression in posterior morphogenesis in the different embryonic germ layers. They shed a new light on the etiology of the caudal dysplasia or caudal regression range of human congenital defects.

  1. Intersection of AHR and Wnt Signaling in Development, Health, and Disease

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    Andrew J. Schneider

    2014-10-01

    Full Text Available The AHR (aryl hydrocarbon receptor and Wnt (wingless-related MMTV integration site signaling pathways have been conserved throughout evolution. Appropriately regulated signaling through each pathway is necessary for normal development and health, while dysregulation can lead to developmental defects and disease. Though both pathways have been vigorously studied, there is relatively little research exploring the possibility of crosstalk between these pathways. In this review, we provide a brief background on (1 the roles of both AHR and Wnt signaling in development and disease, and (2 the molecular mechanisms that characterize activation of each pathway. We also discuss the need for careful and complete experimental evaluation of each pathway and describe existing research that explores the intersection of AHR and Wnt signaling. Lastly, to illustrate in detail the intersection of AHR and Wnt signaling, we summarize our recent findings which show that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD-induced disruption of Wnt signaling impairs fetal prostate development.

  2. Wnt Signaling Regulates Airway Epithelial Stem Cells in Adult Murine Submucosal Glands.

    Science.gov (United States)

    Lynch, Thomas J; Anderson, Preston J; Xie, Weiliang; Crooke, Adrianne K; Liu, Xiaoming; Tyler, Scott R; Luo, Meihui; Kusner, David M; Zhang, Yulong; Neff, Traci; Burnette, Daniel C; Walters, Katherine S; Goodheart, Michael J; Parekh, Kalpaj R; Engelhardt, John F

    2016-06-24

    Wnt signaling is required for lineage commitment of glandular stem cells (SCs) during tracheal submucosal gland (SMG) morphogenesis from the surface airway epithelium (SAE). Whether similar Wnt-dependent processes coordinate SC expansion in adult SMGs following airway injury remains unknown. We found that two Wnt-reporters in mice (BAT-gal and TCF/Lef:H2B-GFP) are coexpressed in actively cycling SCs of primordial glandular placodes and in a small subset of adult SMG progenitor cells that enter the cell cycle 24 hours following airway injury. At homeostasis, these Wnt reporters showed nonoverlapping cellular patterns of expression in the SAE and SMGs. Following tracheal injury, proliferation was accompanied by dynamic changes in Wnt-reporter activity and the analysis of 56 Wnt-related signaling genes revealed unique temporal changes in expression within proximal (gland-containing) and distal (gland-free) portions of the trachea. Wnt stimulation in vivo and in vitro promoted epithelial proliferation in both SMGs and the SAE. Interestingly, slowly cycling nucleotide label-retaining cells (LRCs) of SMGs were spatially positioned near clusters of BAT-gal positive serous tubules. Isolation and culture of tet-inducible H2B-GFP LRCs demonstrated that SMG LRCs were more proliferative than SAE LRCs and culture expanded SMG-derived progenitor cells outcompeted SAE-derived progenitors in regeneration of tracheal xenograft epithelium using a clonal analysis competition assay. SMG-derived progenitors were also multipotent for cell types in the SAE and formed gland-like structures in xenografts. These studies demonstrate the importance of Wnt signals in modulating SC phenotypes within tracheal niches and provide new insight into phenotypic differences of SMG and SAE SCs. Stem Cells 2016.

  3. Wnt/β-catenin signaling is required for development of the exocrine pancreas

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    Sklenka Angela

    2007-01-01

    Full Text Available Abstract Background β-catenin is an essential mediator of canonical Wnt signaling and a central component of the cadherin-catenin epithelial adhesion complex. Dysregulation of β-catenin expression has been described in pancreatic neoplasia. Newly published studies have suggested that β-catenin is critical for normal pancreatic development although these reports reached somewhat different conclusions. In addition, the molecular mechanisms by which loss of β-catenin affects pancreas development are not well understood. The goals of this study then were; 1] to further investigate the role of β-catenin in pancreatic development using a conditional knockout approach and 2] to identify possible mechanisms by which loss of β-catenin disrupts pancreatic development. A Pdx1-cre mouse line was used to delete a floxed β-catenin allele specifically in the developing pancreas, and embryonic pancreata were studied by immunohistochemistry and microarray analysis. Results Pdx1-cre floxed β-catenin animals were viable but demonstrated small body size and shortened median survival. The pancreata from knockout mice were hypoplastic and histologically demonstrated a striking paucity of exocrine pancreas, acinar to duct metaplasia, but generally intact pancreatic islets containing all lineages of endocrine cells. In animals with extensive acinar hypoplasia, putative hepatocyte transdifferention was occasionally observed. Obvious and uniform pancreatic hypoplasia was observed by embryonic day E16.5. Transcriptional profiling of Pdx1-cre floxed β-catenin embryonic pancreata at E14.5, before there was a morphological phenotype, revealed significant decreases in the β-catenin target gene N-myc, and the basic HLH transcription factor PTF1, and an increase of several pancreatic zymogens compared to control animals. By E16.5, there was a dramatic loss of exocrine markers and an increase in Hoxb4, which is normally expressed anterior to the pancreas. Conclusion We

  4. Overexpression of Wnt5a Promotes Angiogenesis in NSCLC

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    Lingli Yao

    2014-01-01

    Full Text Available To evaluate Wnt5a expression and its role in angiogenesis of non-small-cell lung cancer (NSCLC, immunohistochemistry and CD31/PAS double staining were performed to examine the Wnt5a expression and we analyze the relationships between Wnt5a and microvessel density (MVD, vasculogenic mimicry (VM, and some related proteins. About 61.95% of cases of 205 NSCLC specimens exhibited high expression of Wnt5a. Wnt5a expression level was upregulated in the majority of NSCLC tissues, especially in squamous cell carcinoma, while its expression level in adenocarcinoma was the lowest. Wnt5a was also found more frequently expressed in male patients than in female patients. Except for histological classification and gender, little association was found between Wnt5a and clinicopathological features. Moreover, Wnt5a was significantly correlated with prognosis. Overall, Wnt5a-positive expression in patients with NSCLC indicated shorter survival time. As for vascularization in NSCLC, Wnt5a showed close association with VM and MVD. In addition, Wnt5a was positively related with β-catenin-nu, VE-cadherin, MMP2, and MMP9. The results demonstrated that overexpression of Wnt5a may play an important role in NSCLC angiogenesis and it may function via canonical Wnt signal pathway. This study will provide evidence for further research on NSCLC and also will provide new possible target for NSCLC diagnosis and therapeutic strategies.

  5. Regulation of hematopoiesis and the hematopoietic stem cell niche by Wnt signaling pathways

    Institute of Scientific and Technical Information of China (English)

    Michael J Nemeth; David M Bodine

    2007-01-01

    Hematopoietic stem cells (HSCs) are a rare population of cells that are responsible for life-long generation of blood cells of all lineages. In order to maintain their numbers, HSCs must establish a balance between the opposing cell fates of self-renewal (in which the ability to function as HSCs is retained) and initiation of hematopoietic differentiation. Multiple signaling pathways have been implicated in the regulation of HSC cell fate. One such set of pathways are those activated by the Wnt family of ligands. Wnt signaling pathways play a crucial role during embryogenesis and deregulation of these pathways has been implicated in the formation of solid tumors. Wnt signaling also plays a role in the regulation of stem cells from multiple tissues, such as embryonic, epidermal, and intestinal stem cells. However, the function of Wnt signaling in HSC biology is still controversial. In this review, we will discuss the basic characteristics of the adult HSC and its regulatory microenvironment, the "niche", focusing on the regulation of the HSC and its niche by the Wnt signaling pathways.

  6. Wnt-induced calcium signaling mediates axon growth and guidance in the developing corpus callosum.

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    Hutchins, B Ian; Li, Li; Kalil, Katherine

    2012-01-10

    Wnt5a gradients guide callosal axons by repulsion through Ryk receptors in vivo. We recently found that Wnt5a repels cortical axons and promotes axon outgrowth through calcium signaling in vitro. Here, using cortical slices, we show that Wnt5a signals through Ryk to guide and promote outgrowth of callosal axons after they cross the midline. Calcium transient frequencies in callosal growth cones positively correlate with axon outgrowth rates in vitro. In cortical slices, calcium release through inositol 1,4,5-trisphosphate (IP(3)) receptors and calcium entry through transient receptor potential channels modulate axon growth and guidance. Knocking down Ryk inhibits calcium signaling in cortical axons, reduces rates of axon outgrowth subsequent to midline crossing, and causes axon guidance defects. Calcium- and calmodulin-dependent protein kinase II (CaMKII) is required downstream of Wnt-induced calcium signaling for postcrossing callosal axon growth and guidance. Taken together, these results suggest that growth and guidance of postcrossing callosal axons by Wnt-Ryk-calcium signaling involves axon repulsion through CaMKII.

  7. The Wnt signaling pathway in cellular proliferation and differentiation: A tale of two coactivators.

    Science.gov (United States)

    Teo, Jia-Ling; Kahn, Michael

    2010-09-30

    Wnt signaling pathways play divergent roles during development, normal homeostasis and disease. The responses that result from the activation of the pathway control both proliferation and differentiation. Tight regulation and controlled coordination of the Wnt signaling cascade is required to maintain the balance between proliferation and differentiation. The non-redundant roles of the coactivator proteins CBP and p300, within the context of Wnt signaling are discussed. We highlight their roles as integrators of the various inputs that a cell receives to elicit the correct and coordinated response. We propose that essentially all cellular information - i.e. from other signaling pathways, nutrient levels, etc. - is funneled down into a choice of coactivators usage, either CBP or p300, by their interacting partner beta-catenin (or catenin-like molecules in the absence of beta-catenin) to make the critical decision to either remain quiescent, or once entering cycle to proliferate without differentiation or to initiate the differentiation process.

  8. RANK Signaling Amplifies WNT-Responsive Mammary Progenitors through R-SPONDIN1

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    Purna A. Joshi

    2015-07-01

    Full Text Available Systemic and local signals must be integrated by mammary stem and progenitor cells to regulate their cyclic growth and turnover in the adult gland. Here, we show RANK-positive luminal progenitors exhibiting WNT pathway activation are selectively expanded in the human breast during the progesterone-high menstrual phase. To investigate underlying mechanisms, we examined mouse models and found that loss of RANK prevents the proliferation of hormone receptor-negative luminal mammary progenitors and basal cells, an accompanying loss of WNT activation, and, hence, a suppression of lobuloalveologenesis. We also show that R-spondin1 is depleted in RANK-null progenitors, and that its exogenous administration rescues key aspects of RANK deficiency by reinstating a WNT response and mammary cell expansion. Our findings point to a novel role of RANK in dictating WNT responsiveness to mediate hormone-induced changes in the growth dynamics of adult mammary cells.

  9. Epigenetic regulation of Wnt signaling pathway gene SRY-related HMG-box 17 in papillary thyroid carcinoma

    Institute of Scientific and Technical Information of China (English)

    LI Jing-yi; HAN Chao; ZHENG Li-li; GUO Ming-zhou

    2012-01-01

    Background SRY-related HMG-box 17 (SOX17) encodes a member of the SOX (SRY-related HMG-box) family of transcription factors involved in the regulation of embryonic development and in the determination of the cell fate.Recently,it was considered as a tumor suppressor gene to inhibit canonical Wnt/β-catenin signaling pathway in several malignancies.However,the function of SOX17 in thyroid cancer was unknown.Therefore,we investigated the epigenetic changes and the function of SOX17 in thyroid cancer.Methods The methylation status of the promoter region of SOX17 was detected using methylation-specific PCR in 63 papillary thyroid carcinoma (PTC) tissue,10 normal thyroid tissue,and two thyroid cancer cell lines.Semi-quantitative RT-PCR was used to assess mRNA expression of SOX17 before and after 5-aza-2′-deoxycytidine treatment in thyroid cancer cell lines.Expression of SOX17 and β-catenin were detected by immunohistochemistry in PTC and adjacent tissue.Luciferase reporter assay,colony formation,transfection,and Western blotting were employed to analyze the effect of SOX17 on thyroid cancer cell proliferation and the function of SOX17 in the Wnt signal pathway.Results Loss of SOX17 expression was correlated to the promoter region hypermethylation in thyroid cancer cell lines.Re-expression of SOX17 was found in TPC-1 cell line after 5-aza-2′-deoxycytidine treatment.In primary thyroid cancer,60.3% (38/63) were methylated and 39.7% (25/63) unmethylated.But no methylation was found in noncancerous thyroid tissues.Methylation of SOX17 was associated reversely with β-catenin expression in the cytoplasm or nucleus significantly in the PTC (P <0.05).Colony formation was inhibited by re-expression of SOX17 in TPC-1 cells.SOX17 suppressed the Wnt signaling pathway and the HMG domain was essential for this effect.Conclusions SOX17 was frequently methylated in human PTC.Loss of SOX17 expression was induced by promoter region hypermethylation.SOX17 inhibited thyroid

  10. Non-Canonical Hh Signaling in Cancer—Current Understanding and Future Directions

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    Dongsheng Gu

    2015-08-01

    Full Text Available As a major regulatory pathway for embryonic development and tissue patterning, hedgehog signaling is not active in most adult tissues, but is reactivated in a number of human cancer types. A major milestone in hedgehog signaling in cancer is the Food and Drug Administration (FDA approval of a smoothened inhibitor Vismodegib for treatment of basal cell carcinomas. Vismodegib can block ligand-mediated hedgehog signaling, but numerous additional clinical trials have failed to show significant improvements in cancer patients. Amounting evidence indicate that ligand-independent hedgehog signaling plays an essential role in cancer. Ligand-independent hedgehog signaling, also named non-canonical hedgehog signaling, generally is not sensitive to smoothened inhibitors. What we know about non-canonical hedgehog signaling in cancer, and how should we prevent its activation? In this review, we will summarize recent development of non-canonical hedgehog signaling in cancer, and will discuss potential ways to prevent this type of hedgehog signaling.

  11. BAMBI Promotes C2C12 Myogenic Differentiation by Enhancing Wnt/β-Catenin Signaling

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    Qiangling Zhang

    2015-08-01

    Full Text Available Bone morphogenic protein and activin membrane-bound inhibitor (BAMBI is regarded as an essential regulator of cell proliferation and differentiation that represses transforming growth factor-β and enhances Wnt/β-catenin signaling in various cell types. However, its role in skeletal muscle remains largely unknown. In the current study, we found that the expression level of BAMBI peaked in the early differentiation phase of the C2C12 rodent myoblast cell line. Knockdown of BAMBI via siRNA inhibited C2C12 differentiation, indicated by repressed MyoD, MyoG, and MyHC expression as well as reductions in the differentiation and fusion indices. BAMBI knockdown reduced the activity of Wnt/β-catenin signaling, as characterized by the decreased nuclear translocation of β-catenin and the lowered transcription of Axin2, which is a well-documented target gene of the Wnt/β-catenin signaling pathway. Furthermore, treatment with LiCl, an activator of Wnt/β-catenin signaling, rescued the reduction in C2C12 differentiation caused by BAMBI siRNA. Taken together, our data suggest that BAMBI is required for normal C2C12 differentiation, and that its role in myogenesis is mediated by the Wnt/β-catenin pathway.

  12. Vitamin D Is a Multilevel Repressor of Wnt/β-Catenin Signaling in Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Larriba, María Jesús; González-Sancho, José Manuel; Barbáchano, Antonio; Niell, Núria; Ferrer-Mayorga, Gemma; Muñoz, Alberto, E-mail: amunoz@iib.uam.es [Instituto de Investigaciones Biomédicas “Alberto Sols”, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Arturo Duperier 4, Madrid 28029 (Spain)

    2013-10-21

    The Wnt/β-catenin signaling pathway is abnormally activated in most colorectal cancers and in a proportion of other neoplasias. This activation initiates or contributes to carcinogenesis by regulating the expression of a large number of genes in tumor cells. The active vitamin D metabolite 1α,25-dihydroxyvitamin D{sub 3} (1,25(OH){sub 2}D{sub 3}) inhibits Wnt/β-catenin signaling by several mechanisms at different points along the pathway. Additionally, paracrine actions of 1,25(OH){sub 2}D{sub 3} on stromal cells may also repress this pathway in neighbouring tumor cells. Here we review the molecular basis for the various mechanisms by which 1,25(OH){sub 2}D{sub 3} antagonizes Wnt/β-catenin signaling, preferentially in human colon carcinoma cells, and the consequences of this inhibition for the phenotype and proliferation rate. The effect of the vitamin D system on Wnt/β-catenin signaling and tumor growth in animal models will also be commented in detail. Finally, we revise existing data on the relation between vitamin D receptor expression and vitamin D status and the expression of Wnt/β-catenin pathway genes and targets in cancer patients.

  13. Genome-wide identification of phospho-regulators of Wnt signaling in Drosophila.

    Science.gov (United States)

    Swarup, Sharan; Pradhan-Sundd, Tirthadipa; Verheyen, Esther M

    2015-04-15

    Evolutionarily conserved intercellular signaling pathways regulate embryonic development and adult tissue homeostasis in metazoans. The precise control of the state and amplitude of signaling pathways is achieved in part through the kinase- and phosphatase-mediated reversible phosphorylation of proteins. In this study, we performed a genome-wide in vivo RNAi screen for kinases and phosphatases that regulate the Wnt pathway under physiological conditions in the Drosophila wing disc. Our analyses have identified 54 high-confidence kinases and phosphatases capable of modulating the Wnt pathway, including 22 novel regulators. These candidates were also assayed for a role in the Notch pathway, and numerous phospho-regulators were identified. Additionally, each regulator of the Wnt pathway was evaluated in the wing disc for its ability to affect the mechanistically similar Hedgehog pathway. We identified 29 dual regulators that have the same effect on the Wnt and Hedgehog pathways. As proof of principle, we established that Cdc37 and Gilgamesh/CK1γ inhibit and promote signaling, respectively, by functioning at analogous levels of these pathways in both Drosophila and mammalian cells. The Wnt and Hedgehog pathways function in tandem in multiple developmental contexts, and the identification of several shared phospho-regulators serve as potential nodes of control under conditions of aberrant signaling and disease.

  14. The role of the Wnt signaling pathway in cancer stem cells: prospects for drug development

    Directory of Open Access Journals (Sweden)

    Kim YM

    2014-07-01

    Full Text Available Yong-Mi Kim,1 Michael Kahn2,3 1Children's Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics and Pathology, 2Department of Biochemistry and Molecular Biology, Keck School of Medicine of University of Southern California, 3Norris Comprehensive Cancer Research Center, University of Southern California, Los Angeles, CA, USA Abstract: Cancer stem cells (CSCs, also known as tumor initiating cells are now considered to be the root cause of most if not all cancers, evading treatment and giving rise to disease relapse. They have become a central focus in new drug development. Prospective identification, understanding the key pathways that maintain CSCs, and being able to target CSCs, particularly if the normal stem cell population could be spared, could offer an incredible therapeutic advantage. The Wnt signaling cascade is critically important in stem cell biology, both in homeostatic maintenance of tissues and organs through their respective somatic stem cells and in the CSC/tumor initiating cell population. Aberrant Wnt signaling is associated with a wide array of tumor types. Therefore, the ability to safely target the Wnt signaling pathway offers enormous promise to target CSCs. However, just like the sword of Damocles, significant risks and concerns regarding targeting such a critical pathway in normal stem cell maintenance and tissue homeostasis remain ever present. With this in mind, we review recent efforts in modulating the Wnt signaling cascade and critically analyze therapeutic approaches at various stages of development. Keywords: beta-catenin, CBP, p300, wnt inhibition

  15. Wnt signaling inhibits adrenal steroidogenesis by cell-autonomous and non-cell-autonomous mechanisms.

    Science.gov (United States)

    Walczak, Elisabeth M; Kuick, Rork; Finco, Isabella; Bohin, Natacha; Hrycaj, Steven M; Wellik, Deneen M; Hammer, Gary D

    2014-09-01

    Wnt/β-catenin (βcat) signaling is critical for adrenal homeostasis. To elucidate how Wnt/βcat signaling elicits homeostatic maintenance of the adrenal cortex, we characterized the identity of the adrenocortical Wnt-responsive population. We find that Wnt-responsive cells consist of sonic hedgehog (Shh)-producing adrenocortical progenitors and differentiated, steroidogenic cells of the zona glomerulosa, but not the zona fasciculata and rarely cells that are actively proliferating. To determine potential direct inhibitory effects of βcat signaling on zona fasciculata-associated steroidogenesis, we used the mouse ATCL7 adrenocortical cell line that serves as a model system of glucocorticoid-producing fasciculata cells. Stimulation of βcat signaling caused decreased corticosterone release consistent with the observed reduced transcription of steroidogenic genes Cyp11a1, Cyp11b1, Star, and Mc2r. Decreased steroidogenic gene expression was correlated with diminished steroidogenic factor 1 (Sf1; Nr5a1) expression and occupancy on steroidogenic promoters. Additionally, βcat signaling suppressed the ability of Sf1 to transactivate steroidogenic promoters independent of changes in Sf1 expression level. To investigate Sf1-independent effects of βcat on steroidogenesis, we used Affymetrix gene expression profiling of Wnt-responsive cells in vivo and in vitro. One candidate gene identified, Ccdc80, encodes a secreted protein with unknown signaling mechanisms. We report that Ccdc80 is a novel βcat-regulated gene in adrenocortical cells. Treatment of adrenocortical cells with media containing secreted Ccdc80 partially phenocopies βcat-induced suppression of steroidogenesis, albeit through an Sf1-independent mechanism. This study reveals multiple mechanisms of βcat-mediated suppression of steroidogenesis and suggests that Wnt/βcat signaling may regulate adrenal homeostasis by inhibiting fasciculata differentiation and promoting the undifferentiated state of progenitor

  16. Modeling oscillatory control in NF-¿B, p53 and Wnt signaling

    DEFF Research Database (Denmark)

    Mengel, Benedicte; Hunziker, Alexander; Pedersen, Lykke;

    2010-01-01

    Oscillations are commonly observed in cellular behavior and span a wide range of timescales, from seconds in calcium signaling to 24 hours in circadian rhythms. In between lie oscillations with time periods of 1-5 hours seen in NF-¿B, p53 and Wnt signaling, which play key roles in the immune system...

  17. Exosomes mediate stromal mobilization of autocrine Wnt-PCP signaling in breast cancer cell migration.

    Science.gov (United States)

    Luga, Valbona; Zhang, Liang; Viloria-Petit, Alicia M; Ogunjimi, Abiodun A; Inanlou, Mohammad R; Chiu, Elaine; Buchanan, Marguerite; Hosein, Abdel Nasser; Basik, Mark; Wrana, Jeffrey L

    2012-12-21

    Stroma in the tumor microenvironment plays a critical role in cancer progression, but how it promotes metastasis is poorly understood. Exosomes are small vesicles secreted by many cell types and enable a potent mode of intercellular communication. Here, we report that fibroblast-secreted exosomes promote breast cancer cell (BCC) protrusive activity and motility via Wnt-planar cell polarity (PCP) signaling. We show that exosome-stimulated BCC protrusions display mutually exclusive localization of the core PCP complexes, Fzd-Dvl and Vangl-Pk. In orthotopic mouse models of breast cancer, coinjection of BCCs with fibroblasts dramatically enhances metastasis that is dependent on PCP signaling in BCCs and the exosome component, Cd81 in fibroblasts. Moreover, we demonstrate that trafficking in BCCs promotes tethering of autocrine Wnt11 to fibroblast-derived exosomes. This work reveals an intercellular communication pathway whereby fibroblast exosomes mobilize autocrine Wnt-PCP signaling to drive BCC invasive behavior.

  18. Mesenchymal Wnt signaling promotes formation of sternum and thoracic body wall.

    Science.gov (United States)

    Snowball, John; Ambalavanan, Manoj; Cornett, Bridget; Lang, Richard; Whitsett, Jeffrey; Sinner, Debora

    2015-05-15

    Midline defects account for approximately 5% of congenital abnormalities observed at birth. However, the molecular mechanisms underlying the formation of the ventral body wall are not well understood. Recent studies linked mutations in Porcupine-an O-acetyl transferase mediating Wnt ligand acylation-with defects in the thoracic body wall. We hypothesized that anomalous Wnt signaling is involved in the pathogenesis of defective closure of the thoracic body wall. We generated a mouse model wherein Wntless (Wls), which encodes a cargo receptor mediating secretion of Wnt ligands, was conditionally deleted from the developing mesenchyme using Dermo1Cre mice. Wls(f/f);Dermo1(Cre/+) embryos died during mid-gestation. At E13.5, skeletal defects were observed in the forelimbs, jaw, and rib cage. At E14.5, midline defects in the thoracic body wall began to emerge: the sternum failed to fuse and the heart protruded through the body wall at the midline (ectopia cordis). To determine the molecular mechanism underlying the phenotype observed in Wls(f/f);Dermo1(Cre/+) embryos, we tested whether Wnt/β-catenin signaling was operative in developing the embryonic ventral body wall using Axin2(LacZ) and BatGal reporter mice. While Wnt/β-catenin signaling activity was observed at the midline of the ventral body wall before sternal fusion, this pattern of activity was altered and scattered throughout the body wall after mesenchymal deletion of Wls. Mesenchymal cell migration was disrupted in Wls(f/f);Dermo1(Cre/+) thoracic body wall partially due to anomalous β-catenin independent Wnt signaling as determined by in vitro assays. Deletion of Lrp5 and Lrp6 receptors, which mediate Wnt/β-catenin signaling in the mesenchyme, partially recapitulated the phenotype observed in the chest midline of Wls(f/f);Dermo1(Cre/+) embryos supporting a role for Wnt/β-catenin signaling activity in the normal formation of the ventral body wall mesenchyme. We conclude that Wls-mediated secretion of Wnt

  19. ERβ induces the differentiation of cultured osteoblasts by both Wnt/β-catenin signaling pathway and estrogen signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xinhua [Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha (China); Wang, Xiaoyuan [Department of Nephrology, Xi An Honghui Hospital, Xi an (China); Hu, Xiongke; Chen, Yong; Zeng, Kefeng [Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha (China); Zhang, Hongqi, E-mail: zhq9699@126.com [Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha (China)

    2015-07-01

    Although 17β-estradial (E2) is known to stimulate bone formation, the underlying mechanisms are not fully understood. Recent studies have implicated the Wnt/β-catenin pathway as a major signaling cascade in bone biology. The interactions between Wnt/β-catenin signaling pathway and estrogen signaling pathways have been reported in many tissues. In this study, E2 significantly increased the expression of β-catenin by inducing phosphorylations of GSK3β at serine 9. ERβ siRNAs were transfected into MC3T3-E1 cells and revealed that ERβ involved E2-induced osteoblasts proliferation and differentiation via Wnt/β-catenin signaling. The osteoblast differentiation genes (BGP, ALP and OPN) and proliferation related gene (cyclin D1) expression were significantly induced by E2-mediated ERβ. Furthermore immunofluorescence and immunoprecipitation analysis demonstrated that E2 induced the accumulation of β-catenin protein in the nucleus which leads to interaction with T-cell-specific transcription factor/lymphoid enhancer binding factor (TCF/LEF) transcription factors. Taken together, these findings suggest that E2 promotes osteoblastic proliferation and differentiation by inducing proliferation-related and differentiation-related gene expression via ERβ/GSK-3β-dependent Wnt/β-catenin signaling pathway. Our findings provide novel insights into the mechanisms of action of E2 in osteoblastogenesis. - Highlights: • 17β-estradial (E2) promotes GSK3-β phosphorylation. • E2 activates the Wnt/β-catenin signaling pathway. • The Wnt/β-catenin signaling pathway interacts with estrogen signaling pathways. • E2-mediated ER induced osteoblast differentiation and proliferation related genes expression.

  20. Cadmium induces Wnt signaling to upregulate proliferation and survival genes in sub-confluent kidney proximal tubule cells

    Directory of Open Access Journals (Sweden)

    Wolff Natascha A

    2010-05-01

    Full Text Available Abstract Background The class 1 carcinogen cadmium (Cd2+ disrupts the E-cadherin/β-catenin complex of epithelial adherens junctions (AJs and causes renal cancer. Deregulation of E-cadherin adhesion and changes in Wnt/β-catenin signaling are known to contribute to carcinogenesis. Results We investigated Wnt signaling after Cd2+-induced E-cadherin disruption in sub-confluent cultured kidney proximal tubule cells (PTC. Cd2+ (25 μM, 3-9 h caused nuclear translocation of β-catenin and triggered a Wnt response measured by TOPflash reporter assays. Cd2+ reduced the interaction of β-catenin with AJ components (E-cadherin, α-catenin and increased binding to the transcription factor TCF4 of the Wnt pathway, which was upregulated and translocated to the nucleus. While Wnt target genes (c-Myc, cyclin D1 and ABCB1 were up-regulated by Cd2+, electromobility shift assays showed increased TCF4 binding to cyclin D1 and ABCB1 promoter sequences with Cd2+. Overexpression of wild-type and mutant TCF4 confirmed Cd2+-induced Wnt signaling. Wnt signaling elicited by Cd2+ was not observed in confluent non-proliferating cells, which showed increased E-cadherin expression. Overexpression of E-cadherin reduced Wnt signaling, PTC proliferation and Cd2+ toxicity. Cd2+ also induced reactive oxygen species dependent expression of the pro-apoptotic ER stress marker and Wnt suppressor CHOP/GADD153 which, however, did not abolish Wnt response and cell viability. Conclusions Cd2+ induces Wnt signaling in PTC. Hence, Cd2+ may facilitate carcinogenesis of PTC by promoting Wnt pathway-mediated proliferation and survival of pre-neoplastic cells.

  1. Ectodermal Wnt signaling regulates abdominal myogenesis during ventral body wall development.

    Science.gov (United States)

    Zhang, Lingling; Li, Hanjun; Yu, Jian; Cao, Jingjing; Chen, Huihui; Zhao, Haixia; Zhao, Jianzhi; Yao, Yiyun; Cheng, Huihui; Wang, Lifang; Zhou, Rujiang; Yao, Zhengju; Guo, Xizhi

    2014-03-01

    Defects of the ventral body wall are prevalent birth anomalies marked by deficiencies in body wall closure, hypoplasia of the abdominal musculature and multiple malformations across a gamut of organs. However, the mechanisms underlying ventral body wall defects remain elusive. Here, we investigated the role of Wnt signaling in ventral body wall development by inactivating Wls or β-catenin in murine abdominal ectoderm. The loss of Wls in the ventral epithelium, which blocks the secretion of Wnt proteins, resulted in dysgenesis of ventral musculature and genito-urinary tract during embryonic development. Molecular analyses revealed that the dermis and myogenic differentiation in the underlying mesenchymal progenitor cells was perturbed by the loss of ectodermal Wls. The activity of the Wnt-Pitx2 axis was impaired in the ventral mesenchyme of the mutant body wall, which partially accounted for the defects in ventral musculature formation. In contrast, epithelial depletion of β-catenin or Wnt5a did not resemble the body wall defects in the ectodermal Wls mutant. These findings indicate that ectodermal Wnt signaling instructs the underlying mesodermal specification and abdominal musculature formation during ventral body wall development, adding evidence to the theory that ectoderm-mesenchyme signaling is a potential unifying mechanism for the origin of ventral body wall defects.

  2. Canonical and Non-Canonical Aspects of JAK–STAT Signaling: Lessons from Interferons for Cytokine Responses

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    Majoros, Andrea; Platanitis, Ekaterini; Kernbauer-Hölzl, Elisabeth; Rosebrock, Felix; Müller, Mathias; Decker, Thomas

    2017-01-01

    Janus kinase (JAK)–signal transducer and activator of transcription (STAT) signal transduction mediates cytokine responses. Canonical signaling is based on STAT tyrosine phosphorylation by activated JAKs. Downstream of interferon (IFN) receptors, activated JAKs cause the formation of the transcription factors IFN-stimulated gene factor 3 (ISGF3), a heterotrimer of STAT1, STAT2 and interferon regulatory factor 9 (IRF9) subunits, and gamma interferon-activated factor (GAF), a STAT1 homodimer. In recent years, several deviations from this paradigm were reported. These include kinase-independent JAK functions as well as extra- and intranuclear activities of U-STATs without phosphotyrosines. Additionally, transcriptional control by STAT complexes resembling neither GAF nor ISGF3 contributes to transcriptome changes in IFN-treated cells. Our review summarizes the contribution of non-canonical JAK–STAT signaling to the innate antimicrobial immunity imparted by IFN. Moreover, we touch upon functions of IFN pathway proteins beyond the IFN response. These include metabolic functions of IRF9 as well as the regulation of natural killer cell activity by kinase-dead TYK2 and different phosphorylation isoforms of STAT1. PMID:28184222

  3. The Wnt and Notch signalling pathways in the developing cochlea : Formation of hair cells and induction of regenerative potential

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    Zak, Magdalena; Klis, Sjaak F L; Grolman, Wilko

    2015-01-01

    The Wnt and Notch signalling pathways control proliferation, specification, and cell fate choices during embryonic development and in adult life. Hence, there is much interest in both signalling pathways in the context of stem cell biology and tissue regeneration. In the developing ear, the Wnt and

  4. CACN-1/Cactin plays a role in Wnt signaling in C. elegans.

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    Melissa LaBonty

    Full Text Available Wnt signaling is tightly regulated during animal development and controls cell proliferation and differentiation. In C. elegans, activation of Wnt signaling alters the activity of the TCF/LEF transcription factor, POP-1, through activation of the Wnt/β-catenin or Wnt/β-catenin asymmetry pathways. In this study, we have identified CACN-1 as a potential regulator of POP-1 in C. elegans larval development. CACN-1/Cactin is a well-conserved protein of unknown molecular function previously implicated in the regulation of several developmental signaling pathways. Here we have used activation of POPTOP, a POP-1-responsive reporter construct, as a proxy for Wnt signaling. POPTOP requires POP-1 and SYS-1/β-catenin for activation in L4 uterine cells. RNAi depletion experiments show that CACN-1 is needed to prevent excessive activation of POPTOP and for proper levels and/or localization of POP-1. Surprisingly, high POPTOP expression correlates with increased levels of POP-1 in uterine nuclei, suggesting POPTOP may not mirror endogenous gene expression in all respects. Genetic interaction studies suggest that CACN-1 may act partially through LIT-1/NLK to alter POP-1 localization and POPTOP activation. Additionally, CACN-1 is required for proper proliferation of larval seam cells. Depletion of CACN-1 results in a loss of POP-1 asymmetry and reduction of terminal seam cell number, suggesting an adoption of the anterior, differentiated fate by the posterior daughter cells. These findings suggest CACN-1/Cactin modulates Wnt signaling during larval development.

  5. Neural tube derived Wnt signals cooperate with FGF signaling in the formation and differentiation of the trigeminal placodes

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    Graham Anthony

    2008-12-01

    Full Text Available Abstract Background Neurogenic placodes are focal thickenings of the embryonic ectoderm that form in the vertebrate head. It is within these structures that the precursors of the majority of the sensory neurons of the cranial ganglia are specified. The trigeminal placodes, the ophthalmic and maxillomandibular, form close to the midbrain-hindbrain boundary and many lines of evidence have shown that signals emanating from this level of the neuraxis are important for the development of the ophthalmic placode. Results Here, we provide the first evidence that both the ophthalmic and maxillomandibular placodes form under the influence of isthmic Wnt and FGF signals. Activated Wnt signals direct development of the Pax3 expressing ophthalmic placodal field and induce premature differentiation of both the ophthalmic and the maxillomandibular placodes. Similarly, overexpression of Fgf8 directs premature differentiation of the trigeminal placodes. Wnt signals require FGF receptor activity to initiate Pax3 expression and, subsequently, the expression of neural markers, such as Brn3a, within the cranial ectoderm. Furthermore, fibroblast growth factor signaling via the mitogen activated protein kinase pathway is required to maintain early neuronal differentiation within the trigeminal placodes. Conclusion We demonstrate the identity of inductive signals that are necessary for trigeminal ganglion formation. This is the first report that describes how isthmic derived Wnt signals act in concert with fibroblast growth factor signaling. Together, both are necessary and sufficient for the establishment and differentiation of the ophthalmic and maxillomandibular placodes and, consequently, the trigeminal ganglion.

  6. A regulatory loop involving PAX6, MITF, and WNT signaling controls retinal pigment epithelium development.

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    Kapil Bharti

    2012-07-01

    Full Text Available The separation of the optic neuroepithelium into future retina and retinal pigment epithelium (RPE is a critical event in early eye development in vertebrates. Here we show in mice that the transcription factor PAX6, well-known for its retina-promoting activity, also plays a crucial role in early pigment epithelium development. This role is seen, however, only in a background genetically sensitized by mutations in the pigment cell transcription factor MITF. In fact, a reduction in Pax6 gene dose exacerbates the RPE-to-retina transdifferentiation seen in embryos homozygous for an Mitf null allele, and it induces such a transdifferentiation in embryos that are either heterozygous for the Mitf null allele or homozygous for an RPE-specific hypomorphic Mitf allele generated by targeted mutation. Conversely, an increase in Pax6 gene dose interferes with transdifferentiation even in homozygous Mitf null embryos. Gene expression analyses show that, together with MITF or its paralog TFEC, PAX6 suppresses the expression of Fgf15 and Dkk3. Explant culture experiments indicate that a combination of FGF and DKK3 promote retina formation by inhibiting canonical WNT signaling and stimulating the expression of retinogenic genes, including Six6 and Vsx2. Our results demonstrate that in conjunction with Mitf/Tfec Pax6 acts as an anti-retinogenic factor, whereas in conjunction with retinogenic genes it acts as a pro-retinogenic factor. The results suggest that careful manipulation of the Pax6 regulatory circuit may facilitate the generation of retinal and pigment epithelium cells from embryonic or induced pluripotent stem cells.

  7. The inhibition of Wnt/β-catenin signaling pathway in human colon cancer cells by sulindac.

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    Tai, Wei-Ping; Hu, Pin-Jin; Wu, Jing; Lin, Xiang-Chun

    2014-01-01

    The aberrant activation of Wnt/β-catenin signaling plays important roles in the initial development of colon cancer. Sulindac is a commonly used non-steroidal anti-inflammatory drug. We demonstrated the effects of sulindac on growth inhibition, apoptosis induction, and Wnt/β-catenin signaling suppression in human colon cancer cells. Sulindac significantly inhibited proliferation of HT-29 colon cancer cells in a dose- and time-dependent manner. Sulindac was found to induce the apoptosis of HT-29 cells and inhibit the Wnt/β-catenin pathway. The inhibition was further confirmed by the decreased protein levels of β-catenin. The results indicate that sulindac may play a beneficial role in the comprehensive treatment of colon cancer.

  8. Antagonistic cross-regulation between Wnt and Hedgehog signalling pathways controls post-embryonic retinal proliferation.

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    Borday, Caroline; Cabochette, Pauline; Parain, Karine; Mazurier, Nicolas; Janssens, Sylvie; Tran, Hong Thi; Sekkali, Belaïd; Bronchain, Odile; Vleminckx, Kris; Locker, Morgane; Perron, Muriel

    2012-10-01

    Continuous neurogenesis in the adult nervous system requires a delicate balance between proliferation and differentiation. Although Wnt/β-catenin and Hedgehog signalling pathways are thought to share a mitogenic function in adult neural stem/progenitor cells, it remains unclear how they interact in this process. Adult amphibians produce retinal neurons from a pool of neural stem cells localised in the ciliary marginal zone (CMZ). Surprisingly, we found that perturbations of the Wnt and Hedgehog pathways result in opposite proliferative outcomes of neural stem/progenitor cells in the CMZ. Additionally, our study revealed that Wnt and Hedgehog morphogens are produced in mutually exclusive territories of the post-embryonic retina. Using genetic and pharmacological tools, we found that the Wnt and Hedgehog pathways exhibit reciprocal inhibition. Our data suggest that Sfrp-1 and Gli3 contribute to this negative cross-regulation. Altogether, our results reveal an unexpected antagonistic interplay of Wnt and Hedgehog signals that may tightly regulate the extent of neural stem/progenitor cell proliferation in the Xenopus retina.

  9. Inhibition of tankyrases induces Axin stabilization and blocks Wnt signalling in breast cancer cells.

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    Renyue Bao

    Full Text Available Constitutive Wnt signalling is characterized by excessive levels of β-catenin protein and is a frequent occurrence in cancer. APC and Axin are key components of the β-catenin destruction complex that acts to promote β-catenin degradation. The levels of Axin are in turn controlled by tankyrases, members of the PARP-family of poly-ADP-ribosylation enzymes. In colorectal cancer cells, which typically harbor APC mutations, inhibition of tankyrase activity promotes Axin stabilization and attenuates Wnt signalling. Here, we examined the effect of inhibiting tankyrases in breast cancer cells with normal APC. We show that application of the small molecule tankyrase inhibitor, XAV939 or siRNA-mediated abrogation of tankyrase expression increases Axin1 and Axin2 protein levels and attenuates Wnt-induced transcriptional responses in several breast cancer lines. In MDA-MB-231 cells, inhibiton of tankyrase activity also attenuate Wnt3a induced cell migration. Moreover, in both MDA-MB-231 and colorectal cancer cells, XAV939 inhibits cell growth under conditions of serum-deprivation. However, the presence of serum prevents this growth inhibitory effect, although inhibition of Wnt-induced transcriptional and migratory responses was maintained. These results indicate that stabilization of Axin by inhibition of tankyrases alone, may not be an effective means to block tumor cell growth and that combinatorial therapeutic approaches should be considered.

  10. Roles of Wnt/{beta}-catenin signaling in epithelial differentiation of mesenchymal stem cells

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    Wang, Yajing; Sun, Zhaorui; Qiu, Xuefeng [Immunology and Reproductive Biology Laboratory, Medical College of Nanjing University, Nanjing 210093 (China); Jiangsu Key Laboratory of Molecular Medicine, Nanjing 210093 (China); Li, Yan [Jiangsu Centers for Diseases Prevention and Control, Nanjing 210009 (China); Qin, Jizheng [Immunology and Reproductive Biology Laboratory, Medical College of Nanjing University, Nanjing 210093 (China); Jiangsu Key Laboratory of Molecular Medicine, Nanjing 210093 (China); Han, Xiaodong, E-mail: hanxd@nju.edu.cn [Immunology and Reproductive Biology Laboratory, Medical College of Nanjing University, Nanjing 210093 (China); Jiangsu Key Laboratory of Molecular Medicine, Nanjing 210093 (China)

    2009-12-25

    Bone marrow-derived mesenchymal stem cells (MSCs) have been demonstrated to be able to differentiate into epithelial lineage, but the precise mechanisms controlling this process are unclear. Our aim is to explore the roles of Wnt/{beta}-catenin in the epithelial differentiation of MSCs. Using indirect co-culture of rat MSCs with rat airway epithelial cells (RTE), MSCs expressed several airway epithelial markers (cytokeratin 18, tight junction protein occudin, cystic fibrosis transmembrance regulator). The protein levels of some important members in Wnt/{beta}-catenin signaling were determined, suggested down-regulation of Wnt/{beta}-catenin with epithelial differentiation of MSCs. Furthermore, Wnt3{alpha} can inhibit the epithelial differentiation of MSCs. A loss of {beta}-catenin induced by Dickkopf-1 can enhance MSCs differentiation into epithelial cells. Lithium chloride transiently activated {beta}-catenin expression and subsequently decreased {beta}-catenin level and at last inhibited MSCs to differentiate into airway epithelium. Taken together, our study indicated that RTE cells can trigger epithelial differentiation of MSCs. Blocking Wnt/{beta}-catenin signaling may promote MSCs to differentiate towards airway epithelial cells.

  11. The Drosophila homologue of the amyloid precursor protein is a conserved modulator of Wnt PCP signaling.

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    Alessia Soldano

    Full Text Available Wnt Planar Cell Polarity (PCP signaling is a universal regulator of polarity in epithelial cells, but it regulates axon outgrowth in neurons, suggesting the existence of axonal modulators of Wnt-PCP activity. The Amyloid precursor proteins (APPs are intensely investigated because of their link to Alzheimer's disease (AD. APP's in vivo function in the brain and the mechanisms underlying it remain unclear and controversial. Drosophila possesses a single APP homologue called APP Like, or APPL. APPL is expressed in all neurons throughout development, but has no established function in neuronal development. We therefore investigated the role of Drosophila APPL during brain development. We find that APPL is involved in the development of the Mushroom Body αβ neurons and, in particular, is required cell-autonomously for the β-axons and non-cell autonomously for the α-axons growth. Moreover, we find that APPL is a modulator of the Wnt-PCP pathway required for axonal outgrowth, but not cell polarity. Molecularly, both human APP and fly APPL form complexes with PCP receptors, thus suggesting that APPs are part of the membrane protein complex upstream of PCP signaling. Moreover, we show that APPL regulates PCP pathway activation by modulating the phosphorylation of the Wnt adaptor protein Dishevelled (Dsh by Abelson kinase (Abl. Taken together our data suggest that APPL is the first example of a modulator of the Wnt-PCP pathway specifically required for axon outgrowth.

  12. Effect of oxygen on cardiac differentiation in mouse iPS cells: role of hypoxia inducible factor-1 and Wnt/beta-catenin signaling.

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    Tanya L Medley

    Full Text Available BACKGROUND: Disturbances in oxygen levels have been found to impair cardiac organogenesis. It is known that stem cells and differentiating cells may respond variably to hypoxic conditions, whereby hypoxia may enhance stem cell pluripotency, while differentiation of multiple cell types can be restricted or enhanced under hypoxia. Here we examined whether HIF-1alpha modulated Wnt signaling affected differentiation of iPS cells into beating cardiomyocytes. OBJECTIVE: We investigated whether transient and sustained hypoxia affects differentiation of cardiomyocytes derived from murine induced pluripotent stem (iPS cells, assessed the involvement of HIF-1alpha (hypoxia-inducible factor-1alpha and the canonical Wnt pathway in this process. METHODS: Embryoid bodies (EBs derived from iPS cells were differentiated into cardiomyocytes and were exposed either to 24 h normoxia or transient hypoxia followed by a further 13 days of normoxic culture. RESULTS: At 14 days of differentiation, 59 ± 2% of normoxic EBs were beating, whilst transient hypoxia abolished beating at 14 days and EBs appeared immature. Hypoxia induced a significant increase in Brachyury and islet-1 mRNA expression, together with reduced troponin C expression. Collectively, these data suggest that transient and sustained hypoxia inhibits maturation of differentiating cardiomyocytes. Compared to normoxia, hypoxia increased HIF-1alpha, Wnt target and ligand genes in EBs, as well as accumulation of HIF-1alpha and beta-catenin in nuclear protein extracts, suggesting involvement of the Wnt/beta-catenin pathway. CONCLUSION: Hypoxia impairs cardiomyocyte differentiation and activates Wnt signaling in undifferentiated iPS cells. Taken together the study suggests that oxygenation levels play a critical role in cardiomyocyte differentiation and suggest that hypoxia may play a role in early cardiogenesis.

  13. Activation of the wnt/β-Catenin Signaling Pathway in Polymyositis, Dermatomyositis and Duchenne Muscular Dystrophy

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    Liu, Fuchen; Liang, Zonglai; Xu, Jingwen; Li, Wei; Zhao, Dandan; Zhao, Yuying

    2016-01-01

    Background and Purpose The wnt/β-catenin signaling pathway plays a critical role in embryonic development and adult-tissue homeostasis. Recent investigations implicate the importance of wnt/β-catenin signaling in normal wound healing and its sustained activation being associated with fibrogenesis. We investigated the immunolocalization and activation of wnt/β-catenin in polymyositis (PM), dermatomyositis (DM), and Duchenne muscular dystrophy (DMD). Methods Immunofluorescence staining and Western blot analysis of β-catenin were performed in muscle specimens from 6 PM, 8 DM, and 6 DMD subjects. The β-catenin/Tcf4 DNA-binding activity in muscle was studied using an electrophoretic mobility shift assay (EMSA), and serum wnt/β-catenin/Tcf transcriptional activity was measured using a luciferase reporter gene assay. Results Immunoreactivity for β-catenin was found in the cytoplasm and nuclei of muscle fibers in PM, DM, and DMD. The protein level of β-catenin was elevated, and EMSA analysis confirmed the activation of wnt/β-catenin signaling. The transcriptional activities of β-catenin/Tcf in the circulation were increased in patients with PM, DM, and DMD, especially in those with interstitial lung disease, and these transcriptional activities decreased when PM or DM patients exhibited obvious clinical improvements. Conclusions Our findings indicate that wnt/β-catenin signaling is activated in PM, DM, and DMD. Its activation in muscle tissue and the circulation may play a role in modulating muscle regeneration and be at least partly involved in the process of muscle and pulmonary fibrosis. PMID:27165423

  14. Integration of the beta-catenin-dependent Wnt pathway with integrin signaling through the adaptor molecule Grb2.

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    Steve P Crampton

    Full Text Available BACKGROUND: THE COMPLEXITY OF WNT SIGNALING LIKELY STEMS FROM TWO SOURCES: multiple pathways emanating from frizzled receptors in response to wnt binding, and modulation of those pathways and target gene responsiveness by context-dependent signals downstream of growth factor and matrix receptors. Both rac1 and c-jun have recently been implicated in wnt signaling, however their upstream activators have not been identified. METHODOLOGY/PRINCIPAL FINDINGS: Here we identify the adapter protein Grb2, which is itself an integrator of multiple signaling pathways, as a modifier of beta-catenin-dependent wnt signaling. Grb2 synergizes with wnt3A, constitutively active (CA LRP6, Dvl2 or CA-beta-catenin to drive a LEF/TCF-responsive reporter, and dominant negative (DN Grb2 or siRNA to Grb2 block wnt3A-mediated reporter activity. MMP9 is a target of beta-catenin-dependent wnt signaling, and an MMP9 promoter reporter is also responsive to signals downstream of Grb2. Both a jnk inhibitor and DN-c-jun block transcriptional activation downstream of Dvl2 and Grb2, as does DN-rac1. Integrin ligation by collagen also synergizes with wnt signaling as does overexpression of Focal Adhesion Kinase (FAK, and this is blocked by DN-Grb2. CONCLUSIONS/SIGNIFICANCE: These data suggest that integrin ligation and FAK activation synergize with wnt signaling through a Grb2-rac-jnk-c-jun pathway, providing a context-dependent mechanism for modulation of wnt signaling.

  15. The thrombospondin repeat containing protein MIG-21 controls a left-right asymmetric Wnt signaling response in migrating C. elegans neuroblasts

    NARCIS (Netherlands)

    Middelkoop, T.C.; Williams, L.; Yang, P.T.; Luchtenberg, J.; Betist, M.C.; Ji, N.; van Oudenaarden, A.; Kenyon, C.; Korswagen, H.C.

    2012-01-01

    Wnt proteins are secreted signaling molecules that play a central role in development and adult tissue homeostasis. Although several Wnt signal transduction mechanisms have been described in detail, it is still largely unknown how cells are specified to adopt such different Wnt signaling responses.

  16. FGF signaling regulates Wnt ligand expression to control vulval cell lineage polarity in C. elegans.

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    Minor, Paul J; He, Ting-Fang; Sohn, Chang Ho; Asthagiri, Anand R; Sternberg, Paul W

    2013-09-01

    The interpretation of extracellular cues leading to the polarization of intracellular components and asymmetric cell divisions is a fundamental part of metazoan organogenesis. The Caenorhabditis elegans vulva, with its invariant cell lineage and interaction of multiple cell signaling pathways, provides an excellent model for the study of cell polarity within an organized epithelial tissue. Here, we show that the fibroblast growth factor (FGF) pathway acts in concert with the Frizzled homolog LIN-17 to influence the localization of SYS-1, a component of the Wnt/β-catenin asymmetry pathway, indirectly through the regulation of cwn-1. The source of the FGF ligand is the primary vulval precursor cell (VPC) P6.p, which controls the orientation of the neighboring secondary VPC P7.p by signaling through the sex myoblasts (SMs), activating the FGF pathway. The Wnt CWN-1 is expressed in the posterior body wall muscle of the worm as well as in the SMs, making it the only Wnt expressed on the posterior and anterior sides of P7.p at the time of the polarity decision. Both sources of cwn-1 act instructively to influence P7.p polarity in the direction of the highest Wnt signal. Using single molecule fluorescence in situ hybridization, we show that the FGF pathway regulates the expression of cwn-1 in the SMs. These results demonstrate an interaction between FGF and Wnt in C. elegans development and vulval cell lineage polarity, and highlight the promiscuous nature of Wnts and the importance of Wnt gradient directionality within C. elegans.

  17. Wnt5a uses CD146 as a receptor to regulate cell motility and convergent extension

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    Ye, Zhongde; Zhang, Chunxia; Tu, Tao; Sun, Min; Liu, Dan; Lu, Di; Feng, Jing; Yang, Dongling; Liu, Feng; Yan, Xiyun

    2013-12-01

    Dysregulation of Wnt signalling leads to developmental defects and diseases. Non-canonical Wnt signalling via planar cell polarity proteins regulates cell migration and convergent extension; however, the underlying mechanisms are poorly understood. Here we report that Wnt5a uses CD146 as a receptor to regulate cell migration and zebrafish embryonic convergent extension. CD146 binds to Wnt5a with the high affinity required for Wnt5a-induced activation of Dishevelled (Dvl) and c-jun amino-terminal kinase (JNK). The interaction between CD146 and Dvl2 is enhanced on Wnt5a treatment. Mutation of the Dvl2-binding region impairs its ability to activate JNK, promote cell migration and facilitate the formation of cell protrusions. Knockdown of Dvls impairs CD146-induced cell migration. Interestingly, CD146 inhibits canonical Wnt signalling by promoting β-catenin degradation. Our results suggest a model in which CD146 acts as a functional Wnt5a receptor in regulating cell migration and convergent extension, turning off the canonical Wnt signalling branch.

  18. Hh and Wnt signaling regulate formation of olig2+ neurons in the zebrafish cerebellum.

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    McFarland, Karen A; Topczewska, Jolanta M; Weidinger, Gilbert; Dorsky, Richard I; Appel, Bruce

    2008-06-01

    The cerebellum, which forms from anterior hindbrain, coordinates motor movements and balance. Sensory input from the periphery is relayed and modulated by cerebellar interneurons, which are organized in layers. The mechanisms that specify the different neurons of the cerebellum and direct its layered organization remain poorly understood. Drawing from investigations of spinal cord, we hypothesized that the embryonic cerebellum is patterned on the dorsoventral axis by opposing morphogens. We tested this using zebrafish. Here we show that expression of olig2, which encodes a bHLH transcription factor, marks a distinct subset of neurons with similarities to eurydendroid neurons, the principal efferent neurons of the teleost cerebellum. In combination with other markers, olig2 reveals a dorsoventral organization of cerebellar neurons in embryos. Disruption of Hedgehog signaling, which patterns the ventral neural tube, produced a two-fold increase in the number of olig2(+) neurons. By contrast, olig2(+) neurons did not develop in embryos deficient for Wnt signaling, which patterns dorsal neural tube, nor did they develop in embryos deficient for both Hedgehog and Wnt signaling. Our data indicate that Hedgehog and Wnt work in opposition across the dorsoventral axis of the cerebellum to regulate formation of olig2(+) neurons. Specifically, we propose that Hedgehog limits the range of Wnt signaling, which is necessary for olig2(+) neuron development.

  19. Epigenetic repression of ROR2 has a Wnt-mediated, pro-tumourigenic role in colon cancer

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    López-Otín Carlos

    2010-06-01

    Full Text Available Abstract Background Wnt factors control cell differentiation through semi-independent molecular cascades known as the β-catenin-dependent (canonical and -independent (non-canonical Wnt signalling pathways. Genetic and epigenetic alteration of components of the canonical Wnt signalling pathway is one of the primary mechanisms underlying colon cancer. Despite increasing evidence of the role of the non-canonical pathways in tumourigenesis, however, the underlying molecular mechanisms are poorly understood. Results Here we report that the receptor tyrosine kinase-like orphan receptor 2 (ROR2, a transmembrane receptor for Wnt factors that activates non-canonical pathways, is frequently repressed by aberrant promoter hypermethylation in human colon cancer cell lines and primary tumours. By restoring ROR2 activity in colon cancer cells harbouring ROR2 promoter hypermethylation, we show that the role of ROR2 in colon cancer cells is mediated, at least in part, by canonical Wnt and that its epigenetic-dependent loss can be pro-tumourigenic. Conclusions Our data show the importance of epigenetic alterations of ROR2 in colon cancer, highlighting the close interconnection between canonical and non-canonical Wnt signalling pathways in this type of tumour.

  20. Wnt7b stimulates embryonic lung growth by coordinately increasing the replication of epithelium and mesenchyme.

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    Rajagopal, Jayaraj; Carroll, Thomas J; Guseh, J Sawalla; Bores, Sam A; Blank, Leah J; Anderson, William J; Yu, Jing; Zhou, Qiao; McMahon, Andrew P; Melton, Douglas A

    2008-05-01

    The effects of Wnt7b on lung development were examined using a conditional Wnt7b-null mouse. Wnt7b-null lungs are markedly hypoplastic, yet display largely normal patterning and cell differentiation. In contrast to findings in prior hypomorphic Wnt7b models, we find decreased replication of both developing epithelium and mesenchyme, without abnormalities of vascular smooth muscle development. We further demonstrate that Wnt7b signals to neighboring cells to activate both autocrine and paracrine canonical Wnt signaling cascades. In contrast to results from hypomorphic models, we show that Wnt7b modulates several important signaling pathways in the lung. Together, these cascades result in the coordinated proliferation of adjacent epithelial and mesenchymal cells to stimulate organ growth with few alterations in differentiation and patterning.

  1. Moringin activates Wnt canonical pathway by inhibiting GSK3β in a mouse model of experimental autoimmune encephalomyelitis

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    Giacoppo S

    2016-10-01

    Full Text Available Sabrina Giacoppo,1 Thangavelu Soundara Rajan,1 Gina Rosalinda De Nicola,2 Renato Iori,2 Placido Bramanti,1 Emanuela Mazzon1 1IRCCS Centre Neurolesi “Bonino-Pulejo”, Messina, Italy; 2Council for Agricultural Research and Economics, Research Centre for Industrial Crops (CREA-CIN, Bologna, Italy Abstract: Aberrant canonical Wnt–β-catenin signaling has been reported in multiple sclerosis (MS, although the results are controversial. The present study aimed to examine the role of the Wnt–β-catenin pathway in experimental MS and also to test moringin (4-[α-L-rhamnopyranosyloxy]-benzyl isothiocyanate, resulting from exogenous myrosinase hydrolysis of the natural phytochemical glucomoringin 4(α-L-rhamnosyloxy-benzyl glucosinolate as a modulator of neuroinflammation via the β-catenin–PPARγ axis. Experimental autoimmune encephalomyelitis (EAE, the most common model of MS, was induced in C57BL/6 mice by immunization with MOG35–55. Released moringin (10 mg/kg glucomoringin +5 µL myrosinase/mouse was administered daily for 1 week before EAE induction and continued until mice were killed on day 28 after EAE induction. Our results clearly showed that the Wnt–β-catenin pathway was downregulated in the EAE model, whereas moringin pretreatment was able to avert this. Moringin pretreatment normalizes the aberrant Wnt–β-catenin pathway, resulting in GSK3β inhibition and β-catenin upregulation, which regulates T-cell activation (CD4 and FoxP3, suppresses the main inflammatory mediators (IL-1β, IL-6, and COX2, through activation of PPARγ. In addition, moringin attenuates apoptosis by reducing the expression of the Fas ligand and cleaved caspase 9, and in parallel increases antioxidant Nrf2 expression in EAE mice. Taken together, our results provide an interesting discovery in identifying moringin as a modulator of the Wnt–β-catenin signaling cascade and as a new potential therapeutic target for MS treatment. Keywords: Wnt

  2. Immunohistochemical study of hair follicle stem cells in regenerated hair follicles induced by Wnt10b

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    Zhang, Yiming; Xing, Yizhan; Guo, Haiying; Ma, Xiaogen; Li, Yuhong

    2016-01-01

    The regulation of the periodic regeneration of hair follicles is complicated. Although Wnt10b has been reported to induce hair follicle regeneration, the characteristics of induced hair follicles, especially the target cells of Wnt10b, have not yet been clearly elucidated. Thus, we systematically evaluated the expression and proliferation patterns of Wnt10b-induced hair follicles. We found that Wnt10b promoted the proliferation of hair follicle stem cells from 24 hours after AdWnt10b injection. Seventy-two hours after AdWnt10b injection, cells outside of bulge area began to proliferate. When the induced hair follicle entered full anagen, although the hair follicle stem cells were normal, canonical Wnt signaling was maintained in the hair precortex cells. Our results reveal that the target cells that overexpressed Wnt10b included hair follicle stem cells, hair precortex cells, and matrix cells.

  3. WNT signaling controls expression of pro-apoptotic BOK and BAX in intestinal cancer

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    Zeilstra, Jurrit; Joosten, Sander P.J. [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Wensveen, Felix M. [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands); Dessing, Mark C.; Schuetze, Denise M. [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Eldering, Eric [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands); Spaargaren, Marcel [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Pals, Steven T., E-mail: s.t.pals@amc.uva.nl [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands)

    2011-03-04

    Research highlights: {yields} Intestinal adenomas initiated by aberrant activation of the WNT pathway displayed an increased sensitivity to apoptosis. {yields} Expression profiling of apoptosis-related genes in Apc{sup Min/+} mice revealed the differential expression of pro-apoptotic Bok and Bax. {yields} APC-mutant adenomatous crypts in FAP patients showed strongly increased BAX immunoreactivity. {yields} Blocking of {beta}-catenin/TCF-4-mediated signaling in colon cancer cells reduced the expression of BOK and BAX. -- Abstract: In a majority of cases, colorectal cancer is initiated by aberrant activation of the WNT signaling pathway. Mutation of the genes encoding the WNT signaling components adenomatous polyposis coli or {beta}-catenin causes constitutively active {beta}-catenin/TCF-mediated transcription, driving the transformation of intestinal crypts to cancer precursor lesions, called dysplastic aberrant crypt foci. Deregulated apoptosis is a hallmark of adenomatous colon tissue. However, the contribution of WNT signaling to this process is not fully understood. We addressed this role by analyzing the rate of epithelial apoptosis in aberrant crypts and adenomas of the Apc{sup Min/+} mouse model. In comparison with normal crypts and adenomas, aberrant crypts displayed a dramatically increased rate of apoptotic cell death. Expression profiling of apoptosis-related genes along the crypt-villus axis and in Apc mutant adenomas revealed increased expression of two pro-apoptotic Bcl-2 family members in intestinal adenomas, Bok and Bax. Analysis of the colon of familial adenomatous polyposis (FAP) patients along the crypt-to-surface axis, and of dysplastic crypts, corroborated this expression pattern. Disruption of {beta}-catenin/TCF-4-mediated signaling in the colorectal cancer cell line Ls174T significantly decreased BOK and BAX expression, confirming WNT-dependent regulation in intestinal epithelial cells. Our results suggest a feedback mechanism by which

  4. β-catenin/Wnt signaling controls progenitor fate in the developing and regenerating zebrafish retina

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    Meyers Jason R

    2012-08-01

    Full Text Available Abstract Background The zebrafish retina maintains two populations of stem cells: first, the germinal zone or ciliary marginal zone (CMZ contains multipotent retinal progenitors that add cells to the retinal periphery as the fish continue to grow; second, radial glia (Müller cells occasionally divide asymmetrically to generate committed progenitors that differentiate into rod photoreceptors, which are added interstitially throughout the retina with growth. Retinal injury stimulates Müller glia to dedifferentiate, re-enter the cell cycle, and generate multipotent retinal progenitors similar to those in the CMZ to replace missing neurons. The specific signals that maintain these two distinct populations of endogenous retinal stem cells are not understood. Results We used genetic and pharmacological manipulation of the β-catenin/Wnt signaling pathway to show that it is required to maintain proliferation in the CMZ and that hyperstimulation of β-catenin/Wnt signaling inhibits normal retinal differentiation and expands the population of proliferative retinal progenitors. To test whether similar effects occur during regeneration, we developed a method for making rapid, selective photoreceptor ablations in larval zebrafish with intense light. We found that dephosphorylated β-catenin accumulates in Müller glia as they re-enter the cell cycle following injury, but not in Müller glia that remain quiescent. Activation of Wnt signaling is required for regenerative proliferation, and hyperstimulation results in loss of Müller glia from the INL as all proliferative cells move into the ONL. Conclusions β-catenin/Wnt signaling is thus required for the maintenance of retinal progenitors during both initial development and lesion-induced regeneration, and is sufficient to prevent differentiation of those progenitors and maintain them in a proliferative state. This suggests that the β-catenin/Wnt cascade is part of the shared molecular circuitry that

  5. Effect of micro-nano-hybrid structured hydroxyapatite bioceramics on osteogenic and cementogenic differentiation of human periodontal ligament stem cell via Wnt signaling pathway.

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    Mao, Lixia; Liu, Jiaqiang; Zhao, Jinglei; Chang, Jiang; Xia, Lunguo; Jiang, Lingyong; Wang, Xiuhui; Lin, Kaili; Fang, Bing

    2015-01-01

    The surface structure of bioceramic scaffolds is crucial for its bioactivity and osteoinductive ability, and in recent years, human periodontal ligament stem cells have been certified to possess high osteogenic and cementogenic differential ability. In the present study, hydroxyapatite (HA) bioceramics with micro-nano-hybrid surface (mnHA [the hybrid of nanorods and microrods]) were fabricated via hydrothermal reaction of the α-tricalcium phosphate granules as precursors in aqueous solution, and the effects of mnHA on the attachment, proliferation, osteogenic and cementogenic differentiations of human periodontal ligament stem cells as well as the related mechanisms were systematically investigated. The results showed that mnHA bioceramics could promote cell adhesion, proliferation, alkaline phosphatase (ALP) activity, and expression of osteogenic/cementogenic-related markers including runt-related transcription factor 2 (Runx2), ALP, osteocalcin (OCN), cementum attachment protein (CAP), and cementum protein (CEMP) as compared to the HA bioceramics with flat and dense surface. Moreover, mnHA bioceramics stimulated gene expression of low-density lipoprotein receptor-related protein 5 (LRP5) and β-catenin, which are the key genes of canonical Wnt signaling. Moreover, the stimulatory effect on ALP activity and osteogenic and cementogenic gene expression, including that of ALP, OCN, CAP, CEMP, and Runx2 of mnHA bioceramics could be repressed by canonical Wnt signaling inhibitor dickkopf1 (Dkk1). The results suggested that the HA bioceramics with mnHA could act as promising grafts for periodontal tissue regeneration.

  6. Interventions in Wnt signaling as a novel therapeutic approach to improve myocardial infarct healing

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    Hermans Kevin CM

    2012-09-01

    Full Text Available Abstract Following myocardial infarction, wound healing takes place in the infarct area where the non-viable cardiac tissue is replaced by a scar. Inadequate wound healing or insufficient maintenance of the extracellular matrix in the scar can lead to excessive dilatation of the ventricles, one of the hallmarks of congestive heart failure. Therefore, it is important to better understand the wound-healing process in the heart and to develop new therapeutic agents that target the infarct area in order to maintain an adequate cardiac function. One of these potential novel therapeutic targets is Wnt signaling. Wnt signaling plays an important role in embryonic myocardial development but in the adult heart the pathway is thought to be silent. However, there is increasing evidence that components of the Wnt pathway are re-expressed during cardiac repair, implying a regulatory role. Recently, several studies have been published where the effect of interventions in Wnt signaling on infarct healing has been studied. In this review, we will summarize the results of these studies and discuss the effects of these interventions on the different cell types that are involved in the wound healing process.

  7. Mutational analysis of sclerostin shows importance of the flexible loop and the cystine-knot for Wnt-signaling inhibition.

    Science.gov (United States)

    Boschert, Verena; van Dinther, Maarten; Weidauer, Stella; van Pee, Katharina; Muth, Eva-Maria; Ten Dijke, Peter; Mueller, Thomas D

    2013-01-01

    The cystine-knot containing protein Sclerostin is an important negative regulator of bone growth and therefore represents a promising therapeutic target. It exerts its biological task by inhibiting the Wnt (wingless and int1) signaling pathway, which participates in bone formation by promoting the differentiation of mesenchymal stem cells to osteoblasts. The core structure of Sclerostin consists of three loops with the first and third loop (Finger 1 and Finger 2) forming a structured β-sheet and the second loop being unstructured and highly flexible. Biochemical data showed that the flexible loop is important for binding of Sclerostin to Wnt co-receptors of the low-density lipoprotein related-protein family (LRP), by interacting with the Wnt co-receptors LRP5 or -6 it inhibits Wnt signaling. To further examine the structural requirements for Wnt inhibition, we performed an extensive mutational study within all three loops of the Sclerostin core domain involving single and multiple mutations as well as truncation of important regions. By this approach we could confirm the importance of the second loop and especially of amino acids Asn92 and Ile94 for binding to LRP6. Based on a Sclerostin variant found in a Turkish family suffering from Sclerosteosis we generated a Sclerostin mutant with cysteines 84 and 142 exchanged thereby removing the third disulfide bond of the cystine-knot. This mutant binds to LRP6 with reduced binding affinity and also exhibits a strongly reduced inhibitory activity against Wnt1 thereby showing that also elements outside the flexible loop are important for inhibition of Wnt by Sclerostin. Additionally, we examined the effect of the mutations on the inhibition of two different Wnt proteins, Wnt3a and Wnt1. We could detect clear differences in the inhibition of these proteins, suggesting that the mechanism by which Sclerostin antagonizes Wnt1 and Wnt3a is fundamentally different.

  8. Mutational analysis of sclerostin shows importance of the flexible loop and the cystine-knot for Wnt-signaling inhibition.

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    Verena Boschert

    Full Text Available The cystine-knot containing protein Sclerostin is an important negative regulator of bone growth and therefore represents a promising therapeutic target. It exerts its biological task by inhibiting the Wnt (wingless and int1 signaling pathway, which participates in bone formation by promoting the differentiation of mesenchymal stem cells to osteoblasts. The core structure of Sclerostin consists of three loops with the first and third loop (Finger 1 and Finger 2 forming a structured β-sheet and the second loop being unstructured and highly flexible. Biochemical data showed that the flexible loop is important for binding of Sclerostin to Wnt co-receptors of the low-density lipoprotein related-protein family (LRP, by interacting with the Wnt co-receptors LRP5 or -6 it inhibits Wnt signaling. To further examine the structural requirements for Wnt inhibition, we performed an extensive mutational study within all three loops of the Sclerostin core domain involving single and multiple mutations as well as truncation of important regions. By this approach we could confirm the importance of the second loop and especially of amino acids Asn92 and Ile94 for binding to LRP6. Based on a Sclerostin variant found in a Turkish family suffering from Sclerosteosis we generated a Sclerostin mutant with cysteines 84 and 142 exchanged thereby removing the third disulfide bond of the cystine-knot. This mutant binds to LRP6 with reduced binding affinity and also exhibits a strongly reduced inhibitory activity against Wnt1 thereby showing that also elements outside the flexible loop are important for inhibition of Wnt by Sclerostin. Additionally, we examined the effect of the mutations on the inhibition of two different Wnt proteins, Wnt3a and Wnt1. We could detect clear differences in the inhibition of these proteins, suggesting that the mechanism by which Sclerostin antagonizes Wnt1 and Wnt3a is fundamentally different.

  9. Inhibition of Wnt signaling by Wise (Sostdc1) and negative feedback from Shh controls tooth number and patterning.

    Science.gov (United States)

    Ahn, Youngwook; Sanderson, Brian W; Klein, Ophir D; Krumlauf, Robb

    2010-10-01

    Mice carrying mutations in Wise (Sostdc1) display defects in many aspects of tooth development, including tooth number, size and cusp pattern. To understand the basis of these defects, we have investigated the pathways modulated by Wise in tooth development. We present evidence that, in tooth development, Wise suppresses survival of the diastema or incisor vestigial buds by serving as an inhibitor of Lrp5- and Lrp6-dependent Wnt signaling. Reducing the dosage of the Wnt co-receptor genes Lrp5 and Lrp6 rescues the Wise-null tooth phenotypes. Inactivation of Wise leads to elevated Wnt signaling and, as a consequence, vestigial tooth buds in the normally toothless diastema region display increased proliferation and continuous development to form supernumerary teeth. Conversely, gain-of-function studies show that ectopic Wise reduces Wnt signaling and tooth number. Our analyses demonstrate that the Fgf and Shh pathways are major downstream targets of Wise-regulated Wnt signaling. Furthermore, our experiments revealed that Shh acts as a negative-feedback regulator of Wnt signaling and thus determines the fate of the vestigial buds and later tooth patterning. These data provide insight into the mechanisms that control Wnt signaling in tooth development and into how crosstalk among signaling pathways controls tooth number and morphogenesis.

  10. Prednisolone induces the Wnt signalling pathway in 3T3-L1 adipocytes.

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    Fleuren, Wilco W M; Linssen, Margot M L; Toonen, Erik J M; van der Zon, Gerard C M; Guigas, Bruno; de Vlieg, Jacob; Dokter, Wim H A; Ouwens, D Margriet; Alkema, Wynand

    2013-05-01

    Synthetic glucocorticoids are potent anti-inflammatory drugs but show dose-dependent metabolic side effects such as the development of insulin resistance and obesity. The precise mechanisms involved in these glucocorticoid-induced side effects, and especially the participation of adipose tissue in this are not completely understood. We used a combination of transcriptomics, antibody arrays and bioinformatics approaches to characterize prednisolone-induced alterations in gene expression and adipokine secretion, which could underlie metabolic dysfunction in 3T3-L1 adipocytes. Several pathways, including cytokine signalling, Akt signalling, and Wnt signalling were found to be regulated at multiple levels, showing that these processes are targeted by prednisolone. These results suggest that mechanisms by which prednisolone induce insulin resistance include dysregulation of wnt signalling and immune response processes. These pathways may provide interesting targets for the development of improved glucocorticoids.

  11. Wnt/Ryk signaling contributes to neuropathic pain by regulating sensory neuron excitability and spinal synaptic plasticity in rats.

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    Liu, Su; Liu, Yue-Peng; Huang, Zhi-Jiang; Zhang, Yan-Kai; Song, Angela A; Ma, Ping-Chuan; Song, Xue-Jun

    2015-12-01

    Treating neuropathic pain continues to be a major clinical challenge and underlying mechanisms of neuropathic pain remain elusive. We have recently demonstrated that Wnt signaling, which is important in developmental processes of the nervous systems, plays critical roles in the development of neuropathic pain through the β-catenin-dependent pathway in the spinal cord and the β-catenin-independent pathway in primary sensory neurons after nerve injury. Here, we report that Wnt signaling may contribute to neuropathic pain through the atypical Wnt/Ryk signaling pathway in rats. Sciatic nerve injury causes a rapid-onset and long-lasting expression of Wnt3a, Wnt5b, and Ryk receptors in primary sensory neurons, and dorsal horn neurons and astrocytes. Spinal blocking of the Wnt/Ryk receptor signaling inhibits the induction and persistence of neuropathic pain without affecting normal pain sensitivity and locomotor activity. Blocking activation of the Ryk receptor with anti-Ryk antibody, in vivo or in vitro, greatly suppresses nerve injury-induced increased intracellular Ca and hyperexcitability of the sensory neurons, and also the enhanced plasticity of synapses between afferent C-fibers and the dorsal horn neurons, and activation of the NR2B receptor and the subsequent Ca-dependent signals CaMKII, Src, ERK, PKCγ, and CREB in sensory neurons and the spinal cord. These findings indicate a critical mechanism underlying the pathogenesis of neuropathic pain and suggest that targeting the Wnt/Ryk signaling may be an effective approach for treating neuropathic pain.

  12. Hipk2 and PP1c Cooperate to Maintain Dvl Protein Levels Required for Wnt Signal Transduction

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    Nobuyuki Shimizu

    2014-09-01

    Full Text Available The phosphoprotein Dishevelled (Dvl is a common essential component of Wnt/β-catenin and Wnt/planar cell polarity (PCP signaling pathways. However, the regulation and significance of Dvl phosphorylation are not fully understood. Here, we show that homeodomain-interacting protein kinase 2 (Hipk2 facilitates protein phosphatase 1 catalytic subunit (PP1c-mediated dephosphorylation of Dvl via its C-terminal domain and that this dephosphorylation blocks ubiquitination and consequent degradation mediated by the E3 ubiquitin ligase Itch, which targets the phosphorylated form of Dvl proteins. Inhibition of Hipk2 or PP1c function reduces Dvl protein levels and suppresses Wnt/β-catenin and Wnt/PCP pathway-dependent events in mammalian cells and zebrafish embryos, suggesting that Hipk2 and PP1c are essential for maintaining Dvl protein levels that are sufficient to activate Wnt signaling. We also show that Wnt-3a, a Wnt/β-catenin ligand, induces dissociation of the Dvl-Hipk2-PP1c complex and Dvl degradation under high-cell-density conditions. This regulation may be a negative feedback mechanism that fine-tunes Wnt/β-catenin signaling.

  13. The roles of EGF and Wnt signaling during patterning of the C. elegans Bγ/δ Equivalence Group

    OpenAIRE

    Sternberg Paul W; Seah Adeline

    2009-01-01

    Abstract Background During development, different signaling pathways interact to specify cell fate by regulating transcription factors necessary for fate specification and morphogenesis. In Caenorhabditis elegans, the EGF-Ras and Wnt signaling pathways have been shown to interact to specify cell fate in three equivalence groups: the vulval precursor cells (VPCs), the hook competence group (HCG) and P11/12. In the VPCs, HCG and P11/12 pair, EGF and Wnt signaling positively regulate different H...

  14. Wnt signaling in cancer stem cells and colon cancer metastasis [version 1; referees: 3 approved

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    Sayon Basu

    2016-04-01

    Full Text Available Overactivation of Wnt signaling is a hallmark of colorectal cancer (CRC. The Wnt pathway is a key regulator of both the early and the later, more invasive, stages of CRC development. In the normal intestine and colon, Wnt signaling controls the homeostasis of intestinal stem cells (ISCs that fuel, via proliferation, upward movement of progeny cells from the crypt bottom toward the villus and differentiation into all cell types that constitute the intestine. Studies in recent years suggested that cancer stem cells (CSCs, similar to ISCs of the crypts, consist of a small subpopulation of the tumor and are responsible for the initiation and progression of the disease. Although various ISC signature genes were also identified as CRC markers and some of these genes were even demonstrated to have a direct functional role in CRC development, the origin of CSCs and their contribution to cancer progression is still debated. Here, we describe studies supporting a relationship between Wnt-regulated CSCs and the progression of CRC.

  15. High glucose induces podocyte injury via enhanced (prorenin receptor-Wnt-β-catenin-snail signaling pathway.

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    Caixia Li

    Full Text Available (Prorenin receptor (PRR expression is upregulated in diabetes. We hypothesized that PRR contributes to podocyte injury via activation of Wnt-β-catenin-snail signaling pathway. Mouse podocytes were cultured in normal (5 mM or high (25 mM D-glucose for 3 days. Compared to normal glucose, high glucose significantly decreased mRNA and protein expressions of podocin and nephrin, and increased mRNA and protein expressions of PRR, Wnt3a, β-catenin, and snail, respectively. Confocal microscopy studies showed significant reduction in expression and reorganization of podocyte cytoskeleton protein, F-actin, in response to high glucose. Transwell functional permeability studies demonstrated significant increase in albumin flux through podocytes monolayer with high glucose. Cells treated with high glucose and PRR siRNA demonstrated significantly attenuated mRNA and protein expressions of PRR, Wnt3a, β-catenin, and snail; enhanced expressions of podocin mRNA and protein, improved expression and reorganization of F-actin, and reduced transwell albumin flux. We conclude that high glucose induces podocyte injury via PRR-Wnt-β-catenin-snail signaling pathway.

  16. Role of the Wnt pathway in thyroid cancer

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    Ana eSastre-Perona

    2012-02-01

    Full Text Available Aberrant activation of Wnt signaling is involved in the development of several epithelial tumors. Wnt signaling includes two major pathways (i the canonical or Wnt/βcatenin pathway and (ii the non-canonicals pathways, which do not involve βcatenin stabilization. Among these pathways, the Wnt/βcatenin pathway has received most attention during the past years for its critical role in cancer. A number of publications emphasize its role in thyroid cancer. Wnt signaling plays a crucial role in development and epithelial renewal, and components such as βcatenin and Axin are often mutated in thyroid cancer. Although it is accepted that alteration of Wnt signaling is a late event in thyroid cell transformation that affects anaplastic thyroid tumors, recent data also suggest its alteration in papillary thyroid carcinoma with RET/PTC mutations. Therefore, the purpose of this review is to summarize the main relevant data of Wnt/βcatenin signaling in thyroid cancer.

  17. Effects of Shen'an granules on Wnt signaling pathway in mouse models of diabetic nephropathy

    Science.gov (United States)

    Zou, Xin-Rong; Wang, Xiao-Qin; Hu, Ying-Lin; Zhou, Hui-Lan

    2016-01-01

    The effect of Shen'an granules on the Wnt signaling pathway in renal tissues of mouse models of streptozotocin (STZ)-induced diabetic nephropathy was investigated in the present study. A total of 62 BALB/c mice were randomly divided into the normal control (A group), model (B group), losartan (C group), low-dose Shen'an granules (D group), and high-dose Shen'an granules (E group) groups. The mouse model of diabetic nephropathy was established by a single intraperitoneal injection of STZ (150 mg/kg). The animals were treated with drugs for 8 weeks, and blood creatinine, blood urea nitrogen, triglycerides (TG), and total cholesterol (CHOL) were measured prior to and after treatment. PAS staining was performed for observation of glomerular microstructure by light microscope, and western blot analysis was performed to detect Wnt1 protein and β-catenin protein. The results indicated that the quantification of 24-h microalbuminuria, and levels of blood creatinine, urea nitrogen, TG, and CHOL were significantly lower in the high- and low-dose Shen'an granules groups than those in the model group (p<0.05). The expression levels of Wnt1 protein and β-catenin protein in the high- and low-dose Shen'an granules groups were significantly lower than those in the model group (p<0.05). In conclusion, proteinuria, renal dysfunction, and dyslipidemias are closely associated with the abnormal activation of the Wnt signaling pathway in the mouse model of diabetic nephropathy. The mechanism by which Shen'an granules regulate proteinuria, renal function, and blood lipids may be associated with inhibition of the abnormally activated Wnt signaling pathway. PMID:28105085

  18. Notch and Wnt/β-catenin signaling pathway play important roles in activating liver cancer stem cells.

    Science.gov (United States)

    Wang, Ronghua; Sun, Qian; Wang, Peng; Liu, Man; Xiong, Si; Luo, Jing; Huang, Hai; Du, Qiang; Geller, David A; Cheng, Bin

    2016-02-02

    Human hepatocellular carcinoma (HCC) is driven and maintained by liver cancer stem cells (LCSCs) that display stem cell properties. These LCSCs are promoted by the intersecting of Notch and Wnt/β-Catenin signaling pathways. In this study, we demonstrate that LCSCs with markers CD90, CD24, CD13, and CD133 possess stem properties of self-renewal and tumorigenicity in NOD/SCID mice. The increased expression of these markers was correlated with advanced disease stage, larger tumors, and worse overall survival in 61 HCC cases. We also found that both Notch and Wnt/β-catenin signaling pathways played important roles in increasing the stem-ness characteristics of LCSCs. Our data suggested that Notch1 was downstream of Wnt/β-catenin. The active form of Notch1 intracellular domain (NICD) expression depended on Wnt/β-catenin pathway activation. Moreover, Notch1 negatively contributed to Wnt/β-catenin signaling modulation. Knock down of Notch1 with lentivirus N1ShRNA up-regulated the active form of β-catenin. Ectopic expression of NICD with LV-Notch1 in LCSCs attenuated β-catenin/TCF dependent luciferase activity significantly. In addition, there was a non-proteasome mediated feedback loop between Notch1 and Wnt/β-catenin signaling in LCSCs. The central role of Notch and the Wnt/β-catenin signaling pathway in LCSCs may provide an attractive therapeutic strategy against HCC.

  19. Mutations in the human naked cuticle homolog NKD1 found in colorectal cancer alter Wnt/Dvl/beta-catenin signaling.

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    Jianhui Guo

    Full Text Available BACKGROUND: Mutation of Wnt signal antagonists Apc or Axin activates beta-catenin signaling in many cancers including the majority of human colorectal adenocarcinomas. The phenotype of apc or axin mutation in the fruit fly Drosophila melanogaster is strikingly similar to that caused by mutation in the segment-polarity gene, naked cuticle (nkd. Nkd inhibits Wnt signaling by binding to the Dishevelled (Dsh/Dvl family of scaffold proteins that link Wnt receptor activation to beta-catenin accumulation and TCF-dependent transcription, but human NKD genes have yet to be directly implicated in cancer. METHODOLOGY/PRINCIPAL FINDINGS: We identify for the first time mutations in NKD1--one of two human nkd homologs--in a subset of DNA mismatch repair-deficient colorectal tumors that are not known to harbor mutations in other Wnt-pathway genes. The mutant Nkd1 proteins are defective at inhibiting Wnt signaling; in addition, the mutant Nkd1 proteins stabilize beta-catenin and promote cell proliferation, in part due to a reduced ability of each mutant Nkd1 protein to bind and destabilize Dvl proteins. CONCLUSIONS/SIGNIFICANCE: Our data raise the hypothesis that specific NKD1 mutations promote Wnt-dependent tumorigenesis in a subset of DNA mismatch-repair-deficient colorectal adenocarcinomas and possibly other Wnt-signal driven human cancers.

  20. Notch and Wnt/β-catenin signaling pathway play important roles in activating liver cancer stem cells

    Science.gov (United States)

    Wang, Ronghua; Sun, Qian; Wang, Peng; Liu, Man; Xiong, Si; Luo, Jing; Huang, Hai; Du, Qiang; Geller, David A.; Cheng, Bin

    2016-01-01

    Human hepatocellular carcinoma (HCC) is driven and maintained by liver cancer stem cells (LCSCs) that display stem cell properties. These LCSCs are promoted by the intersecting of Notch and Wnt/β-Catenin signaling pathways. In this study, we demonstrate that LCSCs with markers CD90, CD24, CD13, and CD133 possess stem properties of self-renewal and tumorigenicity in NOD/SCID mice. The increased expression of these markers was correlated with advanced disease stage, larger tumors, and worse overall survival in 61 HCC cases. We also found that both Notch and Wnt/β-catenin signaling pathways played important roles in increasing the stem-ness characteristics of LCSCs. Our data suggested that Notch1 was downstream of Wnt/β-catenin. The active form of Notch1 intracellular domain (NICD) expression depended on Wnt/β-catenin pathway activation. Moreover, Notch1 negatively contributed to Wnt/β-catenin signaling modulation. Knock down of Notch1 with lentivirus N1ShRNA up-regulated the active form of β-catenin. Ectopic expression of NICD with LV-Notch1 in LCSCs attenuated β-catenin/TCF dependent luciferase activity significantly. In addition, there was a non-proteasome mediated feedback loop between Notch1 and Wnt/β-catenin signaling in LCSCs. The central role of Notch and the Wnt/β-catenin signaling pathway in LCSCs may provide an attractive therapeutic strategy against HCC. PMID:26735577

  1. Isolation and characterization of Wnt pathway-related genes from Porifera.

    Science.gov (United States)

    Adell, Teresa; Thakur, Archana N; Müller, Werner E G

    2007-09-01

    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 Wnt pathway is the rearrangement of the cell cytoskeleton, through the activation of the subfamily of Ras-like small GTPases. In a recent report we described for the first time the isolation of a Wnt-related gene, Sd-Frizzled, from the most basal animal phylum, the Porifera. In the present study we report the isolation and phylogenetic characterization of several Wnt pathway-related genes from the sponge Suberites domuncula: Sd-TCF/LEF, Sd-GSK3, a recently discovered molecule with a putative function as a Wnt regulator (Sd-LZIC), the small Rho GTPases Sd-RhoA, Sd-Cdc42, and their effector Sd-mrlc. Also the isolation of a secreted frizzled related protein sFRP from another sponge species (Lubomirskia baicalensis) is reported.

  2. Expression of the Wnt signaling system in central nervous system axon guidance and regeneration

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    Edmund eHollis

    2012-02-01

    Full Text Available Wnt signaling is essential for axon wiring throughout the development of the nervous system in vertebrates and invertebrates. In vertebrates, Wnts are expressed in gradients that span the entire anterior-posterior axis in the spinal cord and the medial-lateral axis in the superior colliculus. In the brainstem, Wnts are expressed in more complex gradients along the anterior-posterior axis. These gradients provide directional information for axon pathfinding and positional information for topographic mapping and are detected by cell polarity signaling pathways. The gradient expression of Wnts and the coordinated expression of Wnt signaling systems are regulated by mechanisms which are currently unknown. Injury to the adult spinal cord results in the re-induction of Wnts in multiple cell types around the lesion site and their signaling system in injured axons. Reinduced Wnts form gradients around the lesion site, with the lesion site being the peak. The reinduced Wnts may be responsible for the well-known retraction of descending motor axons through the atypical kinase receptor Ryk. Wnt signaling is an appealing therapeutic target for CNS repair. The mechanisms regulating the reinduction will be informative for therapeutic design.

  3. A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development.

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    Ying Xiao

    2016-07-01

    Full Text Available The Sonic hedgehog (Shh signaling pathway regulates developmental, homeostatic, and repair processes throughout the body. In the skin, touch domes develop in tandem with primary hair follicles and contain sensory Merkel cells. The developmental signaling requirements for touch dome specification are largely unknown. We found dermal Wnt signaling and subsequent epidermal Eda/Edar signaling promoted Merkel cell morphogenesis by inducing Shh expression in early follicles. Lineage-specific gene deletions revealed intraepithelial Shh signaling was necessary for Merkel cell specification. Additionally, a Shh signaling agonist was sufficient to rescue Merkel cell differentiation in Edar-deficient skin. Moreover, Merkel cells formed in Fgf20 mutant skin where primary hair formation was defective but Shh production was preserved. Although developmentally associated with hair follicles, fate mapping demonstrated Merkel cells primarily originated outside the hair follicle lineage. These findings suggest that touch dome development requires Wnt-dependent mesenchymal signals to establish reciprocal signaling within the developing ectoderm, including Eda signaling to primary hair placodes and ultimately Shh signaling from primary follicles to extrafollicular Merkel cell progenitors. Shh signaling often demonstrates pleiotropic effects within a structure over time. In postnatal skin, Shh is known to regulate the self-renewal, but not the differentiation, of touch dome stem cells. Our findings relate the varied effects of Shh in the touch dome to the ligand source, with locally produced Shh acting as a morphogen essential for lineage specification during development and neural Shh regulating postnatal touch dome stem cell maintenance.

  4. A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development.

    Science.gov (United States)

    Xiao, Ying; Thoresen, Daniel T; Miao, Lingling; Williams, Jonathan S; Wang, Chaochen; Atit, Radhika P; Wong, Sunny Y; Brownell, Isaac

    2016-07-01

    The Sonic hedgehog (Shh) signaling pathway regulates developmental, homeostatic, and repair processes throughout the body. In the skin, touch domes develop in tandem with primary hair follicles and contain sensory Merkel cells. The developmental signaling requirements for touch dome specification are largely unknown. We found dermal Wnt signaling and subsequent epidermal Eda/Edar signaling promoted Merkel cell morphogenesis by inducing Shh expression in early follicles. Lineage-specific gene deletions revealed intraepithelial Shh signaling was necessary for Merkel cell specification. Additionally, a Shh signaling agonist was sufficient to rescue Merkel cell differentiation in Edar-deficient skin. Moreover, Merkel cells formed in Fgf20 mutant skin where primary hair formation was defective but Shh production was preserved. Although developmentally associated with hair follicles, fate mapping demonstrated Merkel cells primarily originated outside the hair follicle lineage. These findings suggest that touch dome development requires Wnt-dependent mesenchymal signals to establish reciprocal signaling within the developing ectoderm, including Eda signaling to primary hair placodes and ultimately Shh signaling from primary follicles to extrafollicular Merkel cell progenitors. Shh signaling often demonstrates pleiotropic effects within a structure over time. In postnatal skin, Shh is known to regulate the self-renewal, but not the differentiation, of touch dome stem cells. Our findings relate the varied effects of Shh in the touch dome to the ligand source, with locally produced Shh acting as a morphogen essential for lineage specification during development and neural Shh regulating postnatal touch dome stem cell maintenance.

  5. Chronic hypoxia induces the activation of the Wnt/β-catenin signaling pathway and stimulates hippocampal neurogenesis in wild-type and APPswe-PS1ΔE9 transgenic mice in vivo

    Science.gov (United States)

    Varela-Nallar, Lorena; Rojas-Abalos, Macarena; Abbott, Ana C.; Moya, Esteban A.; Iturriaga, Rodrigo; Inestrosa, Nibaldo C.

    2014-01-01

    Hypoxia modulates proliferation and differentiation of cultured embryonic and adult stem cells, an effect that includes β-catenin, a key component of the canonical Wnt signaling pathway. Here we studied the effect of mild hypoxia on the activity of the Wnt/β-catenin signaling pathway in the hippocampus of adult mice in vivo. The hypoxia-inducible transcription factor-1α (HIF-1α) was analyzed as a molecular control of the physiological hypoxic response. Exposure to chronic hypoxia (10% oxygen for 6–72 h) stimulated the activation of the Wnt/β-catenin signaling pathway. Because the Wnt/β-catenin pathway is a positive modulator of adult neurogenesis, we evaluated whether chronic hypoxia was able to stimulate neurogenesis in the subgranular zone (SGZ) of the hippocampal dentate gyrus. Results indicate that hypoxia increased cell proliferation and neurogenesis in adult wild-type mice as determined by Ki67 staining, Bromodeoxyuridine (BrdU) incorporation and double labeling with doublecortin (DCX). Chronic hypoxia also induced neurogenesis in a double transgenic APPswe-PS1ΔE9 mouse model of Alzheimer’s disease (AD), which shows decreased levels of neurogenesis in the SGZ. Our results show for the first time that exposure to hypoxia in vivo can induce the activation of the Wnt/β-catenin signaling cascade in the hippocampus, suggesting that mild hypoxia may have a therapeutic value in neurodegenerative disorders associated with altered Wnt signaling in the brain and also in pathological conditions in which hippocampal neurogenesis is impaired. PMID:24574965

  6. Chronic hypoxia induces the in vivo activation of the Wnt/β-catenin signaling pathway and stimulates hippocampal neurogenesis in wild-type and APPswe-PS1deltaE9 transgenic mice

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    Lorena eVarela-Nallar

    2014-02-01

    Full Text Available Hypoxia modulates proliferation and differentiation of cultured embryonic and adult stem cells, an effect that includes β-catenin a key component of the canonical Wnt signaling pathway. Here we studied in vivo the effect of mild hypoxia on the activity of the Wnt/β-catenin signaling pathway in the hippocampus of adult mice. As a molecular control of the physiological hypoxic response the hypoxia-inducible transcription factor-1α (HIF-1α was analyzed. Exposure to chronic hypoxia (10% oxygen for 6-72 h stimulated the activation of the Wnt/β-catenin signaling pathway. Because the Wnt/β-catenin pathway is a positive modulator of adult neurogenesis, we evaluated whether chronic hypoxia was able to stimulate neurogenesis in the subgranular zone (SGZ of the hippocampal dentate gyrus. Results indicate that hypoxia increased cell proliferation and neurogenesis in adult wild-type mice as determined by Ki67 staining, BrdU incorporation and double labeling with doublecortin. Chronic hypoxia also induced neurogenesis in double transgenic APPswe-PS1deltaE9 mouse model of Alzheimer’s disease (AD, which shows decreased levels of neurogenesis at the SGZ. Our results show for the first time that in vivo exposure to hypoxia can induce the activation of the Wnt/β-catenin signaling cascade in the hippocampus, suggesting that mild hypoxia may have a therapeutic value in neurodegenerative disorder associated with altered Wnt signaling in the brain and also in pathological conditions in which hippocampal neurogenesis is impaired.

  7. Temporal Perturbation of the Wnt Signaling Pathway in the Control of Cell Reprogramming Is Modulated by TCF1

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    Francesco Aulicino

    2014-05-01

    Full Text Available Cyclic activation of the Wnt/β-catenin signaling pathway controls cell fusion-mediated somatic cell reprogramming. TCFs belong to a family of transcription factors that, in complex with β-catenin, bind and transcriptionally regulate Wnt target genes. Here, we show that Wnt/β-catenin signaling needs to be off during the early reprogramming phases of mouse embryonic fibroblasts (MEFs into iPSCs. In MEFs undergoing reprogramming, senescence genes are repressed and mesenchymal-to-epithelial transition is favored. This is correlated with a repressive activity of TCF1, which contributes to the silencing of Wnt/β-catenin signaling at the onset of reprogramming. In contrast, the Wnt pathway needs to be active in the late reprogramming phases to achieve successful reprogramming. In conclusion, continued activation or inhibition of the Wnt/β-catenin signaling pathway is detrimental to the reprogramming of MEFs; instead, temporal perturbation of the pathway is essential for efficient reprogramming, and the “Wnt-off” state can be considered an early reprogramming marker.

  8. Mindbomb 1, an E3 ubiquitin ligase, forms a complex with RYK to activate Wnt/β-catenin signaling.

    Science.gov (United States)

    Berndt, Jason D; Aoyagi, Atsushi; Yang, Peitzu; Anastas, Jamie N; Tang, Lan; Moon, Randall T

    2011-09-05

    Receptor-like tyrosine kinase (RYK) functions as a transmembrane receptor for the Wnt family of secreted protein ligands. Although RYK undergoes endocytosis in response to Wnt, the mechanisms that regulate its internalization and concomitant activation of Wnt signaling are unknown. We discovered that RYK both physically and functionally interacts with the E3 ubiquitin ligase Mindbomb 1 (MIB1). Overexpression of MIB1 promotes the ubiquitination of RYK and reduces its steady-state levels at the plasma membrane. Moreover, we show that MIB1 is sufficient to activate Wnt/β-catenin (CTNNB1) signaling and that this activity depends on endogenous RYK. Conversely, in loss-of-function studies, both RYK and MIB1 are required for Wnt-3A-mediated activation of CTNNB1. Finally, we identify the Caenorhabditis elegans orthologue of MIB1 and demonstrate a genetic interaction between ceMIB and lin-18/RYK in vulva development. These findings provide insights into the mechanisms of Wnt/RYK signaling and point to novel targets for the modulation of Wnt signaling.

  9. β-Arrestin interacts with the beta/gamma subunits of trimeric G-proteins and dishevelled in the Wnt/Ca(2+ pathway in xenopus gastrulation.

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    Katharina Seitz

    Full Text Available β-Catenin independent, non-canonical Wnt signaling pathways play a major role in the regulation of morphogenetic movements in vertebrates. The term non-canonical Wnt signaling comprises multiple, intracellularly divergent, Wnt-activated and β-Catenin independent signaling cascades including the Wnt/Planar Cell Polarity and the Wnt/Ca(2+ cascades. Wnt/Planar Cell Polarity and Wnt/Ca(2+ pathways share common effector proteins, including the Wnt ligand, Frizzled receptors and Dishevelled, with each other and with additional branches of Wnt signaling. Along with the aforementioned proteins, β-Arrestin has been identified as an essential effector protein in the Wnt/β-Catenin and the Wnt/Planar Cell Polarity pathway. Our results demonstrate that β-Arrestin is required in the Wnt/Ca(2+ signaling cascade upstream of Protein Kinase C (PKC and Ca(2+/Calmodulin-dependent Protein Kinase II (CamKII. We have further characterized the role of β-Arrestin in this branch of non-canonical Wnt signaling by knock-down and rescue experiments in Xenopus embryo explants and analyzed protein-protein interactions in 293T cells. Functional interaction of β-Arrestin, the β subunit of trimeric G-proteins and Dishevelled is required to induce PKC activation and membrane translocation. In Xenopus gastrulation, β-Arrestin function in Wnt/Ca(2+ signaling is essential for convergent extension movements. We further show that β-Arrestin physically interacts with the β subunit of trimeric G-proteins and Dishevelled, and that the interaction between β-Arrestin and Dishevelled is promoted by the beta/gamma subunits of trimeric G-proteins, indicating the formation of a multiprotein signaling complex.

  10. NDRG1 overexpression promotes the progression of esophageal squamous cell carcinoma through modulating Wnt signaling pathway

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    Ai, Runna; Sun, Yulin; Guo, Zhimin; Wei, Wei; Zhou, Lanping; Liu, Fang; Hendricks, Denver T.; Xu, Yang; Zhao, Xiaohang

    2016-01-01

    ABSTRACT N-myc down-regulated gene 1 (NDRG1) has been shown to regulate tumor growth and metastasis in various malignant tumors and also to be dysregulated in esophageal squamous cell carcinoma (ESCC). Here, we show that NDRG1 overexpression (91.9%, 79/86) in ESCC tumor tissues is associated with poor overall survival of esophageal cancer patients. When placed in stable transfectants of the KYSE 30 ESCC cell line generated by lentiviral transduction with the ectopic overexpression of NDRG1, the expression of transducin-like enhancer of Split 2 (TLE2) was decreased sharply, however β−catenin was increased. Mechanistically, NDRG1 physically associates with TLE2 and β−catenin to affect the Wnt pathway. RNA interference and TLE2 overexpression studies demonstrate that NDRG1 fails to active Wnt pathway compared with isogenic wild-type controls. Strikingly, NDRG1 overexpression induces the epithelial mesenchymal transition (EMT) through activating the Wnt signaling pathway in ESCC cells, decreased the expression of E-cadherin and enhanced the expression of Snail. Our study elucidates a mechanism of NDRG1-regulated Wnt pathway activation and EMT via affecting TLE2 and  β-catenin expression in esophageal cancer cells. This indicates a pro-oncogenic role for NDRG1 in esophageal cancer cells whereby it modulates tumor progression. PMID:27414086

  11. Mouse Nkd1, a Wnt antagonist, exhibits oscillatory gene expression in the PSM under the control of Notch signaling.

    Science.gov (United States)

    Ishikawa, Aki; Kitajima, Satoshi; Takahashi, Yu; Kokubo, Hiroki; Kanno, Jun; Inoue, Tohru; Saga, Yumiko

    2004-12-01

    During vertebrate embryogenesis, the formation of reiterated structures along the body axis is dependent upon the generation of the somite by segmentation of the presomitic mesoderm (PSM). Notch signaling plays a crucial role in both the generation and regulation of the molecular clock that provides the spatial information for PSM cells to form somites. In a screen for novel genes involved in somitogenesis, we identified a gene encoding a Wnt antagonist, Nkd1, which is transcribed in an oscillatory manner, and may represent a new member of the molecular clock constituents. The transcription of nkd1 is extremely downregulated in the PSM of vestigial tail (vt/vt), a hypomorphic mutant of Wnt3a, whereas nkd1 oscillations have a similar phase to lunatic fringe (L-fng) transcription and they are arrested in Hes7 (a negative regulator of Notch signaling) deficient embryos. These results suggest that the transcription of nkd1 requires Wnt3a, and that its oscillation patterns depend upon the function of Hes7. Wnt signaling has been postulated to be upstream of Notch signaling but we demonstrate in this study that a Wnt-signal-related gene may also be regulated by Notch signaling. Collectively, our data suggest that the reciprocal interaction of Notch and Wnt signals, and of their respective negative feedback loops, function to organize the segmentation clock required for somitogenesis.

  12. New regulators of Wnt/beta-catenin signaling revealed by integrative molecular screening.

    Science.gov (United States)

    Major, Michael B; Roberts, Brian S; Berndt, Jason D; Marine, Shane; Anastas, Jamie; Chung, Namjin; Ferrer, Marc; Yi, XianHua; Stoick-Cooper, Cristi L; von Haller, Priska D; Kategaya, Lorna; Chien, Andy; Angers, Stephane; MacCoss, Michael; Cleary, Michele A; Arthur, William T; Moon, Randall T

    2008-11-11

    The identification and characterization of previously unidentified signal transduction molecules has expanded our understanding of biological systems and facilitated the development of mechanism-based therapeutics. We present a highly validated small interfering RNA (siRNA) screen that functionally annotates the human genome for modulation of the Wnt/beta-catenin signal transduction pathway. Merging these functional data with an extensive Wnt/beta-catenin protein interaction network produces an integrated physical and functional map of the pathway. The power of this approach is illustrated by the positioning of siRNA screen hits into discrete physical complexes of proteins. Similarly, this approach allows one to filter discoveries made through protein-protein interaction screens for functional contribution to the phenotype of interest. Using this methodology, we characterized AGGF1 as a nuclear chromatin-associated protein that participates in beta-catenin-mediated transcription in human colon cancer cells.

  13. Tcf3 represses Wnt-β-catenin signaling and maintains neural stem cell population during neocortical development.

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    Atsushi Kuwahara

    Full Text Available During mouse neocortical development, the Wnt-β-catenin signaling pathway plays essential roles in various phenomena including neuronal differentiation and proliferation of neural precursor cells (NPCs. Production of the appropriate number of neurons without depletion of the NPC population requires precise regulation of the balance between differentiation and maintenance of NPCs. However, the mechanism that suppresses Wnt signaling to prevent premature neuronal differentiation of NPCs is poorly understood. We now show that the HMG box transcription factor Tcf3 (also known as Tcf7l1 contributes to this mechanism. Tcf3 is highly expressed in undifferentiated NPCs in the mouse neocortex, and its expression is reduced in intermediate neuronal progenitors (INPs committed to the neuronal fate. We found Tcf3 to be a repressor of Wnt signaling in neocortical NPCs in a reporter gene assay. Tcf3 bound to the promoter of the proneural bHLH gene Neurogenin1 (Neurog1 and repressed its expression. Consistent with this, Tcf3 repressed neuronal differentiation and increased the self-renewal activity of NPCs. We also found that Wnt signal stimulation reduces the level of Tcf3, and increases those of Tcf1 (also known as Tcf7 and Lef1, positive mediators of Wnt signaling, in NPCs. Together, these results suggest that Tcf3 antagonizes Wnt signaling in NPCs, thereby maintaining their undifferentiated state in the neocortex and that Wnt signaling promotes the transition from Tcf3-mediated repression to Tcf1/Lef1-mediated enhancement of Wnt signaling, constituting a positive feedback loop that facilitates neuronal differentiation.

  14. Modulating Wnt Signaling Pathway to Enhance Allograft Integration in Orthopedic Trauma Treatment

    Science.gov (United States)

    2014-04-01

    TITLE: Modulating Wnt Signaling Pathway to Enhance Allograft Integration in Orthopedic Trauma Treatment PRINCIPAL INVESTIGATOR: Amarjit S...Integration in Orthopedic Trauma Treatment 5b. GRANT NUMBER W81XWH-10-1-1054 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Amarjit S. Virdi, PhD...practical means of enhancing repair of large bone defects in orthopedic trauma and can be translated into clinical practice in the near future. Figures

  15. Astragaloside IV Inhibits the Up-Regulation of Wnt/β-Catenin Signaling in Rats with Unilateral Ureteral Obstruction

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    Li Wang

    2014-04-01

    Full Text Available Objective: To investigate the effect of Astragaloside IV (AS-IV on the regulation of the Wnt/β-catenin signaling pathway in rats with unilateral ureteral obstruction (UUO. Methods: Rat renal interstitial fibrosis models were prepared using unilateral ureteral ligation. Rats were randomly divided into sham group, sham group with AS-IV (33mg/kg, unilateral ureteral obstruction group, and unilateral ureteral obstruction group receiving varied doses of AS-IV (3.3, 10, and 33 mg/kg. Immunohistochemical analysis, real-time fluorescence quantitative PCR (FQ-PCR, and western blot were used to detect the expression of genes and proteins associated with the Wnt/β-catenin signaling pathway in renal tissues. Results: Levels of Wnt3, Wnt4, and Frizzled gene expression increased significantly in the UUO model; AS-IV was associated with the downregulation of the expression of Wnt3, Wnt4, Frizzled4, p-LRP5, p-LRP6, disheveled, β-catenin, LEF-1, TCF-1, Snail, Jagged 1, Twist, MMP2, and MMP7 proteins in a concentration-dependent manner, while the expression of APC, CK1, and E-cadherin was increased. Conclusions: AS-IV effectively inhibits the up-regulation of proteins in the Wnt/β-catenin signaling pathway in UUO-model rats, indicating its possible inhibitory effects on renal interstitial fibrosis.

  16. Treadmill running exercise prevents senile osteoporosis and upregulates the Wnt signaling pathway in SAMP6 mice.

    Science.gov (United States)

    Chen, Xi; Li, Lihui; Guo, Jianmin; Zhang, Lingli; Yuan, Yu; Chen, Binglin; Sun, Zhongguang; Xu, Jiake; Zou, Jun

    2016-11-01

    This study examined the effects of different exercise intensities and durations on bone mineral density (BMD) and bone strength in senescence-accelerated mouse prone 6 (SAMP6) and determined the involvement of the Wnt signaling pathway in exercise-induced osteogenesis. Three-month-old male SAMP6 mice were randomly assigned to different speeds of treadmill running exercise representing low, medium and high intensity, with the duration of five and nine weeks, respectively. We showed that medium-intensity exercise had positive effects on skeletal health, including BMD and bone strength, and the efficacy was higher than that of low-intensity exercise. Interestingly, high-intensity exercise can maintain or even increase bone strength, despite its negative effects on bone mass. Nine weeks of exercise was superior to 5 weeks of exercise, particularly for low-intensity exercise. Furthermore, these effects of exercise-induced osteogenesis are accompanied by activation of the Wnt signaling pathway. Taken together, these results suggest that the positive effects of exercise on osteoporosis prevention are intensity and duration-dependent, and may involve the regulation of Wnt signaling pathways.

  17. Immunotoxin targeting glypican-3 regresses liver cancer via dual inhibition of Wnt signalling and protein synthesis.

    Science.gov (United States)

    Gao, Wei; Tang, Zhewei; Zhang, Yi-Fan; Feng, Mingqian; Qian, Min; Dimitrov, Dimiter S; Ho, Mitchell

    2015-03-11

    Glypican-3 is a cell surface glycoprotein that associates with Wnt in liver cancer. We develop two antibodies targeting glypican-3, HN3 and YP7. The first antibody recognizes a functional epitope and inhibits Wnt signalling, whereas the second antibody recognizes a C-terminal epitope but does not inhibit Wnt signalling. Both are fused to a fragment of Pseudomonas exotoxin A (PE38) to create immunotoxins. Interestingly, the immunotoxin based on HN3 (HN3-PE38) has superior antitumor activity as compared with YP7 (YP7-PE38) both in vitro and in vivo. Intravenous administration of HN3-PE38 alone, or in combination with chemotherapy, induces regression of Hep3B and HepG2 liver tumour xenografts in mice. This study establishes glypican-3 as a promising candidate for immunotoxin-based liver cancer therapy. Our results demonstrate immunotoxin-induced tumour regression via dual mechanisms: inactivation of cancer signalling via the antibody and inhibition of protein synthesis via the toxin.

  18. Activated WNT signaling in postnatal SOX2-positive dental stem cells can drive odontoma formation.

    Science.gov (United States)

    Xavier, Guilherme M; Patist, Amanda L; Healy, Chris; Pagrut, Ankita; Carreno, Gabriela; Sharpe, Paul T; Martinez-Barbera, Juan Pedro; Thavaraj, Selvam; Cobourne, Martyn T; Andoniadou, Cynthia L

    2015-09-28

    In common with most mammals, humans form only two dentitions during their lifetime. Occasionally, supernumerary teeth develop in addition to the normal complement. Odontoma represent a small group of malformations containing calcified dental tissues of both epithelial and mesenchymal origin, with varying levels of organization, including tooth-like structures. The specific cell type responsible for the induction of odontoma, which retains the capacity to re-initiate de novo tooth development in postnatal tissues, is not known. Here we demonstrate that aberrant activation of WNT signaling by expression of a non-degradable form of β-catenin specifically in SOX2-positive postnatal dental epithelial stem cells is sufficient to generate odontoma containing multiple tooth-like structures complete with all dental tissue layers. Genetic lineage-tracing confirms that odontoma form in a similar manner to normal teeth, derived from both the mutation-sustaining epithelial stem cells and adjacent mesenchymal tissues. Activation of the WNT pathway in embryonic SOX2-positive progenitors results in ectopic expression of secreted signals that promote odontogenesis throughout the oral cavity. Significantly, the inductive potential of epithelial dental stem cells is retained in postnatal tissues, and up-regulation of WNT signaling specifically in these cells is sufficient to promote generation and growth of ectopic malformations faithfully resembling human odontoma.

  19. Targeting stem cell signaling pathways for drug discovery: advances in the Notch and Wnt pathways.

    Science.gov (United States)

    An, Songzhu Michael; Ding, Qiang; Zhang, Jie; Xie, JingYi; Li, LingSong

    2014-06-01

    Signaling pathways transduce extracellular stimuli into cells through molecular cascades to regulate cellular functions. In stem cells, a small number of pathways, notably those of TGF-β/BMP, Hedgehog, Notch, and Wnt, are responsible for the regulation of pluripotency and differentiation. During embryonic development, these pathways govern cell fate specifications as well as the formation of tissues and organs. In adulthood, their normal functions are important for tissue homeostasis and regeneration, whereas aberrations result in diseases, such as cancer and degenerative disorders. In complex biological systems, stem cell signaling pathways work in concert as a network and exhibit crosstalk, such as the negative crosstalk between Wnt and Notch. Over the past decade, genetic and genomic studies have identified a number of potential drug targets that are involved in stem cell signaling pathways. Indeed, discovery of new targets and drugs for these pathways has become one of the most active areas in both the research community and pharmaceutical industry. Remarkable progress has been made and several promising drug candidates have entered into clinical trials. This review focuses on recent advances in the discovery of novel drugs which target the Notch and Wnt pathways.

  20. Reduced E-cadherin facilitates renal cell carcinoma progression by WNT/β-catenin signaling activation.

    Science.gov (United States)

    Zhang, Xinqi; Yang, Mingxi; Shi, Hua; Hu, Jianxin; Wang, Yuanlin; Sun, Zhaolin; Xu, Shuxiong

    2017-02-15

    Reduced expression of E-cadherin was observed in renal cell carcinoma (RCC). However, its potential clinical value and correlation with WNT/β-catenin signaling in RCC progression was still unclear. Immunohistochemical staining was performed in RCC tissue microarray to examine the expression status and prognosis value of E-cadherin and β-catenin. The potential role of E-cadherin in β-catenin translocation was analyzed with immunobloting assays. A significant negative correlation was observed between E-cadherin and β-catenin expression in RCC tissues. E-cadherin inhibits β-catenin translocation from membrane to cytoplasm in RCC tissues, which was an important step for WNT/β-catenin signaling. Reduced E-cadherin expression was associated with poor prognosis. More importantly, E-cadherin-/β-catenin+ was an independent detrimental factor for survival estimation of RCC patients. Reduced E-cadherin expression in RCC promoted cancer progression via WNT/β-catenin signaling pathway activation. E-cadherin/β-catenin provides a valuable prognosis marker for RCC, which may be an effective target for RCC therapy.

  1. Parkin protects dopaminergic neurons from excessive Wnt/{beta}-catenin signaling

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    Rawal, Nina [Laboratory of Molecular Neurobiology, MBB, DBRM, Karolinska Institute, S-17177 Stockholm (Sweden); Corti, Olga [Universite Pierre et Marie Curie-Paris 6, CRICM UMR-S975, Inserm, U975 (France); CNRS, UMR 7225, Paris (France); Sacchetti, Paola [Laboratory of Molecular Neurobiology, MBB, DBRM, Karolinska Institute, S-17177 Stockholm (Sweden); Ardilla-Osorio, Hector [Universite Pierre et Marie Curie-Paris 6, CRICM UMR-S975, Inserm, U975 (France); CNRS, UMR 7225, Paris (France); Sehat, Bita [Cancer Center Karolinska, Karolinska Institute, S-17177 Stockholm (Sweden); Brice, Alexis [Universite Pierre et Marie Curie-Paris 6, CRICM UMR-S975, Inserm, U975 (France); CNRS, UMR 7225, Paris (France); Department of Genetics and Cytogenetics, AP-HP, Groupe Hospitalier Pitie-Salpetriere, Paris (France); Arenas, Ernest, E-mail: Ernest.Arenas@ki.se [Laboratory of Molecular Neurobiology, MBB, DBRM, Karolinska Institute, S-17177 Stockholm (Sweden)

    2009-10-23

    Parkinson's disease (PD) is caused by degeneration of the dopaminergic (DA) neurons of the substantia nigra but the molecular mechanisms underlying the degenerative process remain elusive. Several reports suggest that cell cycle deregulation in post-mitotic neurons could lead to neuronal cell death. We now show that Parkin, an E3 ubiquitin ligase linked to familial PD, regulates {beta}-catenin protein levels in vivo. Stabilization of {beta}-catenin in differentiated primary ventral midbrain neurons results in increased levels of cyclin E and proliferation, followed by increased levels of cleaved PARP and loss of DA neurons. Wnt3a signaling also causes death of post-mitotic DA neurons in parkin null animals, suggesting that both increased stabilization and decreased degradation of {beta}-catenin results in DA cell death. These findings demonstrate a novel regulation of Wnt signaling by Parkin and suggest that Parkin protects DA neurons against excessive Wnt signaling and {beta}-catenin-induced cell death.

  2. Crosstalk between Wnt/β-catenin and estrogen receptor signaling synergistically promotes osteogenic differentiation of mesenchymal progenitor cells.

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    Yanhong Gao

    Full Text Available Osteogenic differentiation from mesenchymal progenitor cells (MPCs are initiated and regulated by a cascade of signaling events. Either Wnt/β-catenin or estrogen signaling pathway has been shown to play an important role in regulating skeletal development and maintaining adult tissue homeostasis. Here, we investigate the potential crosstalk and synergy of these two signaling pathways in regulating osteogenic differentiation of MPCs. We find that the activation of estrogen receptor (ER signaling by estradiol (E2 or exogenously expressed ERα in MPCs synergistically enhances Wnt3A-induced early and late osteogenic markers, as well as matrix mineralization. The E2 or ERα-mediated synergy can be effectively blocked by ERα antagonist tamoxifen. E2 stimulation can enhance endochondral ossification of Wnt3A-transduced mouse fetal limb explants. Furthermore, exogenously expressed ERα significantly enhances the maturity and mineralization of Wnt3A-induced subcutaneous and intramuscular ectopic bone formation. Mechanistically, we demonstrate that E2 does not exert any detectable effect on β-catenin/Tcf reporter activity. However, ERα expression is up-regulated within the first 48h in AdWnt3A-transduced MPCs, whereas ERβ expression is significantly inhibited within 24h. Moreover, the key enzyme for the biosynthesis of estrogens aromatase is modulated by Wnt3A in a biphasic manner, up-regulated at 24h but reduced after 48h. Our results demonstrate that, while ER signaling acts synergistically with Wnt3A in promoting osteogenic differentiation, Wnt3A may crosstalk with ER signaling by up-regulating ERα expression and down-regulating ERβ expression in MPCs. Thus, the signaling crosstalk and synergy between these two pathways should be further explored as a potential therapeutic approach to combating bone and skeletal disorders, such as fracture healing and osteoporosis.

  3. Wnt/β-Catenin Signaling Defines Organizing Centers that Orchestrate Growth and Differentiation of the Regenerating Zebrafish Caudal Fin

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    Daniel Wehner

    2014-02-01

    Full Text Available Zebrafish regenerate their fins via the formation of a population of progenitor cells, the blastema. Wnt/β-catenin signaling is essential for blastemal cell proliferation and patterning of the overlying epidermis. Yet, we find that β-catenin signaling is neither active in the epidermis nor the majority of the proliferative blastemal cells. Rather, tissue-specific pathway interference indicates that Wnt signaling in the nonproliferative distal blastema is required for cell proliferation in the proximal blastema, and signaling in cells lining the osteoblasts directs osteoblast differentiation. Thus, Wnt signaling regulates epidermal patterning, blastemal cell proliferation, and osteoblast maturation indirectly via secondary signals. Gene expression profiling, chromatin immunoprecipitation, and functional rescue experiments suggest that Wnt/β-catenin signaling acts through Fgf and Bmp signaling to control epidermal patterning, whereas retinoic acid and Hedgehog signals mediate its effects on blastemal cell proliferation. We propose that Wnt signaling orchestrates fin regeneration by defining organizing centers that instruct cellular behaviors of adjacent tissues.

  4. Pulsed electromagnetic fields improve bone microstructure and strength in ovariectomized rats through a Wnt/Lrp5/β-catenin signaling-associated mechanism.

    Science.gov (United States)

    Jing, Da; Li, Feijiang; Jiang, Maogang; Cai, Jing; Wu, Yan; Xie, Kangning; Wu, Xiaoming; Tang, Chi; Liu, Juan; Guo, Wei; Shen, Guanghao; Luo, Erping

    2013-01-01

    Growing evidence has demonstrated that pulsed electromagnetic field (PEMF), as an alternative noninvasive method, could promote remarkable in vivo and in vitro osteogenesis. However, the exact mechanism of PEMF on osteopenia/osteoporosis is still poorly understood, which further limits the extensive clinical application of PEMF. In the present study, the efficiency of PEMF on osteoporotic bone microarchitecture and bone quality together with its associated signaling pathway mechanisms was systematically investigated in ovariectomized (OVX) rats. Thirty rats were equally assigned to the Control, OVX and OVX+PEMF groups. The OVX+PEMF group was subjected to daily 8-hour PEMF exposure with 15 Hz, 2.4 mT (peak value). After 10 weeks, the OVX+PEMF group exhibited significantly improved bone mass and bone architecture, evidenced by increased BMD, Tb.N, Tb.Th and BV/TV, and suppressed Tb.Sp and SMI levels in the MicroCT analysis. Three-point bending test suggests that PEMF attenuated the biomechanical strength deterioration of the OVX rat femora, evidenced by increased maximum load and elastic modulus. RT-PCR analysis demonstrated that PEMF exposure significantly promoted the overall gene expressions of Wnt1, LRP5 and β-catenin in the canonical Wnt signaling, but did not exhibit obvious impact on either RANKL or RANK gene expressions. Together, our present findings highlight that PEMF attenuated OVX-induced deterioration of bone microarchitecture and strength in rats by promoting the activation of Wnt/LRP5/β-catenin signaling rather than by inhibiting RANKL-RANK signaling. This study enriches our basic knowledge to the osteogenetic activity of PEMF, and may lead to more efficient and scientific clinical application of PEMF in inhibiting osteopenia/osteoporosis.

  5. Does murine spermatogenesis require WNT signalling? A lesson from Gpr177 conditional knockout mouse models.

    Science.gov (United States)

    Chen, Su-Ren; Tang, J-X; Cheng, J-M; Hao, X-X; Wang, Y-Q; Wang, X-X; Liu, Y-X

    2016-06-30

    Wingless-related MMTV integration site (WNT) proteins and several other components of the WNT signalling pathway are expressed in the murine testes. However, mice mutant for WNT signalling effector β-catenin using different Cre drivers have phenotypes that are inconsistent with each other. The complexity and overlapping expression of WNT signalling cascades have prevented researchers from dissecting their function in spermatogenesis. Depletion of the Gpr177 gene (the mouse orthologue of Drosophila Wntless), which is required for the secretion of various WNTs, makes it possible to genetically dissect the overall effect of WNTs in testis development. In this study, the Gpr177 gene was conditionally depleted in germ cells (Gpr177(flox/flox), Mvh-Cre; Gpr177(flox/flox), Stra8-Cre) and Sertoli cells (Gpr177(flox/flox), Amh-Cre). No obvious defects in fertility and spermatogenesis were observed in these three Gpr177 conditional knockout (cKO) mice at 8 weeks. However, late-onset testicular atrophy and fertility decline in two germ cell-specific Gpr177 deletion mice were noted at 8 months. In contrast, we did not observe any abnormalities of spermatogenesis and fertility, even in 8-month-old Gpr177(flox/flox), Amh-Cre mice. Elevation of reactive oxygen species (ROS) was detected in Gpr177 cKO germ cells and Sertoli cells and exhibited an age-dependent manner. However, significant increase in the activity of Caspase 3 was only observed in germ cells from 8-month-old germ cell-specific Gpr177 knockout mice. In conclusion, GPR177 in Sertoli cells had no apparent influence on spermatogenesis, whereas loss of GPR177 in germ cells disrupted spermatogenesis in an age-dependent manner via elevating ROS levels and triggering germ cell apoptosis.

  6. Interruption of Wnt signaling in Muller cells ameliorates ischemia-induced retinal neovascularization.

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    Kelu Kevin Zhou

    Full Text Available Retinal Müller cells are major producers of inflammatory and angiogenic cytokines which contribute to diabetic retinopathy (DR. Over-activation of the Wnt/β-catenin pathway has been shown to play an important pathogenic role in DR. However, the roles of Müller cell-derived Wnt/β-catenin signaling in retinal neovascularization (NV and DR remain undefined. In the present study, mice with conditional β-catenin knockout (KO in Müller cells were generated and subjected to oxygen-induced retinopathy (OIR and streptozotocin (STZ-induced diabetes. Wnt signaling was evaluated by measuring levels of β-catenin and expression of its target genes using immunoblotting. Retinal vascular permeability was measured using Evans blue as a tracer. Retinal NV was visualized by angiography and quantified by counting pre-retinal nuclei. Retinal pericyte loss was evaluated using retinal trypsin digestion. Electroretinography was performed to examine visual function. No abnormalities were detected in the β-catenin KO mice under normal conditions. In OIR, retinal levels of β-catenin and VEGF were significantly lower in the β-catenin KO mice than in littermate controls. The KO mice also had decreased retinal NV and vascular leakage in the OIR model. In the STZ-induced diabetic model, disruption of β-catenin in Müller cells attenuated over-expression of inflammatory cytokines and ameliorated pericyte dropout in the retina. These findings suggest that Wnt signaling activation in Müller cells contributes to retinal NV, vascular leakage and inflammation and represents a potential therapeutic target for DR.

  7. Quantitative Expression and Co-Localization of Wnt Signalling Related Proteins in Feline Squamous Cell Carcinoma

    Science.gov (United States)

    Marote, Georgina; Abramo, Francesca; McKay, Jenny; Thomson, Calum; Beltran, Mariana; Millar, Michael; Priestnall, Simon; Dobson, Jane; Costantino-Casas, Fernando; Petrou, Terry; McGonnell, Imelda M.; Davies, Anthony J.; Weetman, Malcolm; Garden, Oliver A.; Masters, John R.; Thrasivoulou, Christopher; Ahmed, Aamir

    2016-01-01

    Feline oral squamous cell carcinoma (FOSCC) is an aggressive neoplasm in cats. Little is known about the possible molecular mechanisms that may be involved in the initiation, maintenance and progression of FOSCC. Wnt signalling is critical in development and disease, including many mammalian cancers. In this study, we have investigated the expression of Wnt signalling related proteins using quantitative immunohistochemical techniques on tissue arrays. We constructed tissue arrays with 58 individual replicate tissue samples. We tested for the expression of four key Wnt/ß-catenin transcription targets, namely Cyclin D1 (CCND1 or CD1), FRA1, c-Myc and MMP7. All antibodies showed cross reactivity in feline tissue except MMP7. Quantitative immunohistochemical analysis of single proteins (expressed as area fraction / amount of tissue for normal vs tumor, mean ± SE) showed that the expression of CD1 (3.9 ± 0.5 vs 12.2 ± 0.9), FRA1 (5.5 ± 0.6 vs 16.8 ± 1.1) and c-Myc (5.4 ± 0.5 vs 12.5 ± 0.9) was increased in FOSCC tissue by 2.3 to 3 fold compared to normal controls (ptissue. The global intersection coefficients, a measure of the proximity of two fluorophore labeled entities, showed that there was a significant change (p < 0.01) in the co-localization for all permutations (e.g. CD1/FRA1 etc), except for the nuclear localization of CD1. Our results show that putative targets of Wnt signalling transcription are up-regulated in FOSCC with alterations in the co-localization of these proteins and could serve as a useful marker for the disease. PMID:27559731

  8. Wnt/β-catenin signaling regulates Helicoverpa armigera pupal development by up-regulating c-Myc and AP-4.

    Science.gov (United States)

    Chen, Wei; Xu, Wei-Hua

    2014-10-01

    Seasonally changing environmental conditions perceived by insect brains can be converted into hormonal signals that prompt insects to make a decision to develop or enter developmental arrest (diapause). Diapause is a complex physiological response, and many signaling pathways may participate in its regulation. However, little is known about these regulatory pathways. In this study, we cloned four genes related to the Wnt/β-catenin signaling pathway from Helicoverpa armigera, a pupal diapause species. Western blotting shows that expression of Har-Wnt1, Har-β-catenin, and Har-c-Myc are higher in non-diapause pupal brains than in diapause-destined brains. Har-Wnt1 can promote the accumulation of Har-β-catenin in the nucleus, and Har-β-catenin in turn increases the expression of Har-c-Myc. The blockage of Wnt/β-catenin signaling by the inhibitor XAV939 significantly down-regulates Har-β-catenin and Har-c-Myc expression and delays pupal development, suggesting that the Wnt/β-catenin pathway functions in insect development. Furthermore, Har-c-Myc binds to the promoter of Har-AP-4 and regulates its expression. It has been reported that Har-AP-4 activates diapause hormone (DH) expression and that DH up-regulates the growth hormone ecdysteroid for pupal development. Thus, pupal development is regulated by Wnt/β-catenin signaling through the pathway Wnt-β-catenin-c-Myc-AP-4-DH-ecdysteroid. In contrast, the down-regulation of Wnt/β-catenin signaling is likely to induce insects to enter diapause.

  9. Germ cell-specific sustained activation of Wnt signalling perturbs spermatogenesis in aged mice, possibly through non-coding RNAs

    Science.gov (United States)

    Kumar, Manish; Atkins, Joshua; Cairns, Murray; Ali, Ayesha; Tanwar, Pradeep S.

    2016-01-01

    Dysregulated Wnt signalling is associated with human infertility and testicular cancer. However, the role of Wnt signalling in male germ cells remains poorly understood. In this study, we first confirmed the activity of Wnt signalling in mouse, dog and human testes. To determine the physiological importance of the Wnt pathway, we developed a mouse model with germ cell-specific constitutive activation of βcatenin. In young mutants, similar to controls, germ cell development was normal. However, with age, mutant testes showed defective spermatogenesis, progressive germ cell loss, and flawed meiotic entry of spermatogonial cells. Flow sorting confirmed reduced germ cell populations at the leptotene/zygotene stages of meiosis in mutant group. Using thymidine analogues-based DNA double labelling technique, we further established decline in germ cell proliferation and differentiation. Overactivation of Wnt/βcatenin signalling in a spermatogonial cell line resulted in reduced cell proliferation, viability and colony formation. RNA sequencing analysis of testes revealed significant alterations in the non-coding regions of mutant mouse genome. One of the novel non-coding RNAs was switched on in mutant testes compared to controls. QPCR analysis confirmed upregulation of this unique non-coding RNA in mutant testis. In summary, our results highlight the significance of Wnt signalling in male germ cells. PMID:27992363

  10. Wnt/β-catenin signaling accelerates mouse lung tumorigenesis by imposing an embryonic distal progenitor phenotype on lung epithelium.

    Science.gov (United States)

    Pacheco-Pinedo, Eugenia C; Durham, Amy C; Stewart, Kathleen M; Goss, Ashley M; Lu, Min Min; Demayo, Francesco J; Morrisey, Edward E

    2011-05-01

    Although mutations in Kras are present in 21% of lung tumors, there is a high level of heterogeneity in phenotype and outcome among patients with lung cancer bearing similar mutations, suggesting that other pathways are important. Wnt/β-catenin signaling is a known oncogenic pathway that plays a well-defined role in colon and skin cancer; however, its role in lung cancer is unclear. We have shown here that activation of Wnt/β-catenin in the bronchiolar epithelium of the adult mouse lung does not itself promote tumor development. However, concurrent activation of Wnt/β-catenin signaling and expression of a constitutively active Kras mutant (KrasG12D) led to a dramatic increase in both overall tumor number and size compared with KrasG12D alone. Activation of Wnt/β-catenin signaling altered the KrasG12D tumor phenotype, resulting in a phenotypic switch from bronchiolar epithelium to the highly proliferative distal progenitors found in the embryonic lung. This was associated with decreased E-cadherin expression at the cell surface, which may underlie the increased metastasis of tumors with active Wnt/β-catenin signaling. Together, these data suggest that activation of Wnt/β-catenin signaling can combine with other oncogenic pathways in lung epithelium to produce a more aggressive tumor phenotype by imposing an embryonic distal progenitor phenotype and by decreasing E-cadherin expression.

  11. Bone morphogenetic protein antagonist noggin promotes skin tumorigenesis via stimulation of the Wnt and Shh signaling pathways.

    Science.gov (United States)

    Sharov, Andrey A; Mardaryev, Andrei N; Sharova, Tatyana Y; Grachtchouk, Marina; Atoyan, Ruzanna; Byers, H Randolph; Seykora, John T; Overbeek, Paul; Dlugosz, Andrzej; Botchkarev, Vladimir A

    2009-09-01

    Bone morphogenetic proteins (BMPs) play pivotal roles in the regulation of skin development. To study the role of BMPs in skin tumorigenesis, BMP antagonist noggin was used to generate keratin 14-targeted transgenic mice. In contrast to wild-type mice, transgenic mice developed spontaneous hair follicle-derived tumors, which resemble human trichofolliculoma. Global gene expression profiles revealed that in contrast to anagen hair follicles of wild-type mice, tumors of transgenic mice showed stage-dependent increases in the expression of genes encoding the selected components of Wnt and Shh pathways. Specifically, expression of the Wnt ligands increased at the initiation stage of tumor formation, whereas expression of the Wnt antagonist and tumor suppressor Wnt inhibitory factor-1 decreased, as compared with fully developed tumors. In contrast, expression of the components of Shh pathway increased in fully developed tumors, as compared with the tumor placodes. Consistent with the expression data, pharmacological treatment of transgenic mice with Wnt and Shh antagonists resulted in the stage-dependent inhibition of tumor initiation, and progression, respectively. Furthermore, BMP signaling stimulated Wnt inhibitory factor-1 expression and promoter activity in cultured tumor cells and HaCaT keratinocytes, as well as inhibited Shh expression, as compared with the corresponding controls. Thus, tumor suppressor activity of the BMPs in skin epithelium depends on the local concentrations of noggin and is mediated at least in part via stage-dependent antagonizing of Wnt and Shh signaling pathways.

  12. Regulation of MYC gene expression by aberrant Wnt/β-catenin signaling in colorectal cancer

    Institute of Scientific and Technical Information of China (English)

    Sherri; Rennoll; Gregory; Yochum

    2015-01-01

    The Wnt/β-catenin signaling pathway controls intestinal homeostasis and mutations in components of this pathway are prevalent in human colorectal cancers(CRCs).These mutations lead to inappropriate expression of genes controlled by Wnt responsive DNA elements(WREs). T-cell factor/Lymphoid enhancer factor transcription factors bind WREs and recruit the β-catenin transcriptional co-activator to activate target gene expression. Deregulated expression of the c-MYC proto-oncogene(MYC) by aberrant Wnt/β-catenin signaling drives colorectal carcinogenesis. In this review,we discuss the current literature pertaining to the identification and characterization of WREs that control oncogenic MYC expression in CRCs. A common theme has emerged whereby these WREs often map distally to the MYC genomic locus and control MYC gene expression through long-range chromatin loops with the MYC proximal promoter. We propose that by determining which of these WREs is critical for CRC pathogenesis,novel strategies can be developed to treat individuals suffering from this disease.

  13. Wnt/β-catenin signaling in midbrain dopaminergic neuron specification and neurogenesis.

    Science.gov (United States)

    Joksimovic, Milan; Awatramani, Rajeshwar

    2014-02-01

    Loss of midbrain dopaminergic (mDA) neurons underlies the motor symptoms of Parkinson's disease. Towards cell replacement, studies have focused on mechanisms underlying embryonic mDA production, as a rational basis for deriving mDA neurons from stem cells. We will review studies of β-catenin, an obligate component of the Wnt cascade that is critical to mDA specification and neurogenesis. mDA neurons have a unique origin--the midbrain floor plate (FP). Unlike the hindbrain and spinal cord FP, the midbrain FP is highly neurogenic and Wnt/β-catenin signaling is critical to this difference in neurogenic potential. In β-catenin loss-of-function experiments, the midbrain FP resembles the hindbrain FP, and key mDA progenitor genes such as Otx2, Lmx1a, Msx1, and Ngn2 are downregulated whereas Shh is maintained. Accordingly, the neurogenic capacity of the midbrain FP is diminished, resulting in fewer mDA neurons. Conversely, in β-catenin gain-of-function experiments, the hindbrain FP expresses key mDA progenitor genes, and is highly neurogenic. Interestingly, when excessive β-catenin is supplied to the midbrain FP, less mDA neurons are produced suggesting that the dosage of Wnt/β-catenin signaling is critical. These studies of β-catenin have facilitated new protocols to derive mDA neurons from stem cells.

  14. Wnt3A Induces GSK-3β Phosphorylation and β-Catenin Accumulation Through RhoA/ROCK.

    Science.gov (United States)

    Kim, Jae-Gyu; Kim, Myoung-Ju; Choi, Won-Ji; Moon, Mi-Young; Kim, Hee-Jun; Lee, Jae-Yong; Kim, Jaebong; Kim, Sung-Chan; Kang, Seung Goo; Seo, Goo-Young; Kim, Pyeung-Hyeun; Park, Jae-Bong

    2017-05-01

    In canonical pathway, Wnt3A has been known to stabilize β-catenin through the dissociation between β-catenin and glycogen synthase kinase-3β (GSK-3β) that suppresses the phosphorylation and degradation of β-catenin. In non-canonical signaling pathway, Wnt was known to activate Rho GTPases and to induce cell migration. The cross-talk between canonical and non-canonical pathways by Wnt signaling; however, has not been fully elucidated. Here, we revealed that Wnt3A induces not only the phosphorylation of GSK-3β and accumulation of β-catenin but also RhoA activation in RAW264.7 and HEK293 cells. Notably, sh-RhoA and Tat-C3 abolished both the phosphorylation of GSK-3β and accumulation of β-catenin. Y27632, an inhibitor of Rho-associated coiled coil kinase (ROCK) and si-ROCK inhibited both GSK-3β phosphorylation and β-catenin accumulation. Furthermore, active domain of ROCK directly phosphorylated the purified recombinant GSK-3β in vitro. In addition, Wnt3A-induced cell proliferation and migration, which were inhibited by Tat-C3 and Y27632. Taken together, we propose the cross-talk between canonical and non-canonical signaling pathways of Wnt3A, which induces GSK-3β phosphorylation and β-catenin accumulation through RhoA and ROCK activation. J. Cell. Physiol. 232: 1104-1113, 2017. © 2016 Wiley Periodicals, Inc.

  15. Wnt/β-catenin signaling plays a key role in the development of spondyloarthritis

    Science.gov (United States)

    Xie, Wanqing; Zhou, Lijiang; Li, Shan; Hui, Tianqian; Chen, Di

    2015-01-01

    Spondyloarthritis (SpA) is a group of diseases consisting of psoriatic arthritis (PsA), reactive arthritis, arthritis related to inflammatory bowel disease (a subgroup of juvenile idiopathic arthritis), and ankylosing spondylitis (the prototype of SpA). Axial bone formation and the combination of concurrent erosion and new bone formation are specific characteristics of SpA disease. The use of anti-proinflammatory cytokines, such as inhibitors of tumor necrosis factor α (TNF-α), appears to be the greatest advance in the treatment of SpA over the past 20 years. However, TNF-α blockers do not halt new bone formation. Recent clinical observations and animal studies demonstrate that Wnt signaling proteins and natural Wnt inhibitors, such as DKK1 and sclerostin, are likely to play important roles in the process of ankylosis in SpA, and could potentially serve as therapeutic targets for the treatment of SpA. PMID:26629686

  16. Wnt/β-catenin signaling plays a key role in the development of spondyloarthritis.

    Science.gov (United States)

    Xie, Wanqing; Zhou, Lijiang; Li, Shan; Hui, Tianqian; Chen, Di

    2016-01-01

    Spondyloarthritis (SpA) is a group of diseases consisting of psoriatic arthritis (PsA), reactive arthritis, arthritis related to inflammatory bowel disease (a subgroup of juvenile idiopathic arthritis), and ankylosing spondylitis (the prototype of SpA). Axial bone formation and the combination of concurrent erosion and new bone formation are specific characteristics of SpA disease. The use of antiproinflammatory cytokines, such as inhibitors of tumor necrosis factor α (TNF-α), appears to be the greatest advance in the treatment of SpA over the past 20 years. However, TNF-α blockers do not halt new bone formation. Recent clinical observations and animal studies demonstrate that Wnt signaling proteins and natural Wnt inhibitors, such as DKK1 and sclerostin, are likely to play important roles in the process of ankylosis in SpA, and could potentially serve as therapeutic targets for the treatment of SpA.

  17. Null and hypomorph Prickle1 alleles in mice phenocopy human Robinow syndrome and disrupt signaling downstream of Wnt5a

    Directory of Open Access Journals (Sweden)

    Chunqiao Liu

    2014-09-01

    Full Text Available Planar cell polarity (PCP signaling plays a critical role in tissue morphogenesis. In mammals, disruption of three of the six “core PCP” components results in polarity-dependent defects with rotated cochlear hair cell stereocilia and open neural tube. We recently demonstrated a role of Prickle1, a core PCP molecule in Drosophila, in mammalian neuronal development. To examine Prickle1 function along a broader developmental window, we generated three mutant alleles in mice. We show that the complete loss of Prickle1 leads to systemic tissue outgrowth defects, aberrant cell organization and disruption of polarity machinery. Curiously, Prickle1 mutants recapitulate the characteristic features of human Robinow syndrome and phenocopy mouse mutants with Wnt5a or Ror2 gene defects, prompting us to explore an association of Prickle1 with the Wnt pathway. We show that Prickle1 is a proteasomal target of Wnt5a signaling and that Dvl2, a target of Wnt5a signaling, is misregulated in Prickle1 mutants. Our studies implicate Prickle1 as a key component of the Wnt-signaling pathway and suggest that Prickle1 mediates some of the WNT5A-associated genetic defects in Robinow syndrome.

  18. Wnt signaling through the Ror receptor in the nervous system

    NARCIS (Netherlands)

    Petrova, Iveta M; Malessy, Martijn J; Verhaagen, J.; Fradkin, Lee G; Noordermeer, Jasprina N

    2014-01-01

    The receptor tyrosine kinase-like orphan receptor (Ror) proteins are conserved tyrosine kinase receptors that play roles in a variety of cellular processes that pattern tissues and organs during vertebrate and invertebrate development. Ror signaling is required for skeleton and neuronal development

  19. Specific targeting of Wnt/β-catenin signaling in human melanoma cells by a dietary triterpene lupeol.

    Science.gov (United States)

    Tarapore, Rohinton S; Siddiqui, Imtiaz A; Saleem, Mohammad; Adhami, Vaqar M; Spiegelman, Vladimir S; Mukhtar, Hasan

    2010-10-01

    Wingless (Wnt) signaling pathway regulates a variety of cellular processes including proliferation, differentiation, survival, apoptosis and cell motility. Aberrant activation of Wnt/β-catenin pathway has been observed in approximately one-third of melanomas and this subset has very poor prognosis suggesting that targeting Wnt signaling could be a promising strategy against this subtype. Mel 928 and Mel 1241 melanoma cells representative of cells with constitutive activation of Wnt/β-catenin signaling pathway and Mel 1011 representative of cells that lack this pathway were treated with a dietary triterpene lupeol and its effects on growth, proliferation, β-catenin transcriptional activity and Wnt target genes were determined both in vitro and in vivo. Lupeol treatment to Mel 928 and Mel 1241 but not Mel 1011 cells resulted in a dose-dependent (i) decrease in cell viability, (ii) induction of apoptosis, (iii) decrease in colonogenic potential, (iv) decrease in β-catenin transcriptional activity and (v) decrease in the expression of Wnt target genes. Most importantly, lupeol restricted the translocation of β-catenin from the cytoplasm to the nucleus. Lupeol also decreased the growth of Mel 928 but not Mel 1011-derived tumors implanted in the athymic nude mice. The decrease in Mel 928-derived tumor growth was associated with a decrease in the expression of Wnt target genes c-myc, cyclin D1, proliferation markers proliferating cell nuclear antigen and Ki-67 and invasion marker osteopontin. We suggest that lupeol alone or as an adjuvant to current therapies could be developed as an agent for the management of human melanomas harboring constitutive Wnt/β-catenin signaling.

  20. (Pro)renin Receptor Is an Amplifier of Wnt/β-Catenin Signaling in Kidney Injury and Fibrosis.

    Science.gov (United States)

    Li, Zhen; Zhou, Lili; Wang, Yongping; Miao, Jinhua; Hong, Xue; Hou, Fan Fan; Liu, Youhua

    2017-03-07

    The (pro)renin receptor (PRR) is a transmembrane protein with multiple functions. However, its regulation and role in the pathogenesis of CKD remain poorly defined. Here, we report that PRR is a downstream target and an essential component of Wnt/β-catenin signaling. In mouse models, induction of CKD by ischemia-reperfusion injury (IRI), adriamycin, or angiotensin II infusion upregulated PRR expression in kidney tubular epithelium. Immunohistochemical staining of kidney biopsy specimens also revealed induction of renal PRR in human CKD. Overexpression of either Wnt1 or β-catenin induced PRR mRNA and protein expression in vitro Notably, forced expression of PRR potentiated Wnt1-mediated β-catenin activation and augmented the expression of downstream targets such as fibronectin, plasminogen activator inhibitor 1, and α-smooth muscle actin (α-SMA). Conversely, knockdown of PRR by siRNA abolished β-catenin activation. PRR potentiation of Wnt/β-catenin signaling did not require renin, but required vacuolar H(+) ATPase activity. In the mouse model of IRI, transfection with PRR or Wnt1 expression vectors promoted β-catenin activation, aggravated kidney dysfunction, and worsened renal inflammation and fibrotic lesions. Coexpression of PRR and Wnt1 had a synergistic effect. In contrast, knockdown of PRR expression ameliorated kidney injury and fibrosis after IRI. These results indicate that PRR is both a downstream target and a crucial element in Wnt signal transmission. We conclude that PRR can promote kidney injury and fibrosis by amplifying Wnt/β-catenin signaling.

  1. Wnt3a signaling promotes proliferation,myogenic differentiation,and migration of rat bone marrow mesenchymal stem cells

    Institute of Scientific and Technical Information of China (English)

    Yan-chang SHANG; Shu-hui WANG; Fu XIONG; Cui-ping ZHAO; Fu-ning PENG; Shan-wei FENG; Mei-shan LI; Yong LI; Cheng ZHANG

    2007-01-01

    Aim:To investigate the effects of the wingless-related MMTV integration site 3A (Wnt3a) signaling on the proliferation,migration,and the myogenic and adipogenic differentiation of rat bone marrow mesenchymal stem cells (rMSC). Methods:Primary MSC were isolated and cultured from Spragne-Dawley rats and characterized by flow cytometry. Mouse L cells were transfected with Wnt3a cDNA,and conditioned media containing active Wnt3a proteins were prepared. Cell proliferation was evaluated by cell count and 5-bromodeoxyuridine incorporation assay.The migration of rMSC was performed by using a transwell migration and wound healing assay. The myogenic and adipogenic differentiation in rMSC were examined by light microscopy,immunofluorescence,and RT-PCR at different time points after myogenic or adipogenic introduction. Results:Wnt3a signaling induced β-catenin nuclear translocation and activated the Writ pathway in rMSC.In the presence of Wnt3a,rMSC proliferated more rapidly than the control cells,keeping their differentiation potential. Moreover,Wnt3a signaling induced 2.62%and 3.76% of rMSC-expressed desmin and myosin heavy chain after being cultured in myogenic medium. The myogenic differentiation genes,including Pax7,MyoD,Myf5,Myf4,and myogenin,were activated after Wnt3a treatment. On the other hand,Wnt3a inhibited the adipogenic differentiation in rMSC through the downregulated expression of CCAAT/enhancer-binding protein alpha (C/EBPalpha)and peroxisome proliferator-activaled receptor gamma (PPARgamma). Furthermore,Wnt3a promoted the migration capacity of rMSC. Conclusion:The results indicate that Wnt3a signaling can induce myogenic differentiation in rMSC. Wnt3a signaling is also involved in the regulation of the proliferation and migration of rMSC. These results could provide a rational foundation for cell-based tissue repair in humans.

  2. Osteogenesis on nanoparticulate mineralized collagen scaffolds via autogenous activation of the canonical BMP receptor signaling pathway.

    Science.gov (United States)

    Ren, Xiaoyan; Bischoff, David; Weisgerber, Daniel W; Lewis, Michael S; Tu, Victor; Yamaguchi, Dean T; Miller, Timothy A; Harley, Brendan A C; Lee, Justine C

    2015-05-01

    Skeletal regenerative medicine frequently incorporates deliverable growth factors to stimulate osteogenesis. However, the cost and side effects secondary to supraphysiologic dosages of growth factors warrant investigation of alternative methods of stimulating osteogenesis for clinical utilization. In this work, we describe growth factor independent osteogenic induction of human mesenchymal stem cells (hMSCs) on a novel nanoparticulate mineralized collagen glycosaminoglycan scaffold (MC-GAG). hMSCs demonstrated elevated osteogenic gene expression and mineralization on MC-GAG with minimal to no effect upon addition of BMP-2 when compared to non-mineralized scaffolds (Col-GAG). To investigate the intracellular pathways responsible for the increase in osteogenesis, we examined the canonical and non-canonical pathways downstream from BMP receptor activation. Constitutive Smad1/5 phosphorylation with nuclear translocation occurred on MC-GAG independent of BMP-2, whereas Smad1/5 phosphorylation depended on BMP-2 stimulation on Col-GAG. When non-canonical BMPR signaling molecules were examined, ERK1/2 phosphorylation was found to be decreased in MC-GAG but elevated in Col-GAG. No differences in Smad2/3 or p38 activation were detected. Collectively, these results demonstrated that MC-GAG scaffolds induce osteogenesis without exogenous BMP-2 addition via endogenous activation of the canonical BMP receptor signaling pathway.

  3. Label-free LC-MSMS analysis of vitreous from autoimmune uveitis reveals a significant decrease in secreted Wnt signalling inhibitors DKK3 and SFRP2.

    Science.gov (United States)

    Hauck, Stefanie M; Hofmaier, Florian; Dietter, Johannes; Swadzba, Margarete E; Blindert, Marcel; Amann, Barbara; Behler, Jennifer; Kremmer, Elisabeth; Ueffing, Marius; Deeg, Cornelia A

    2012-07-19

    Equine recurrent uveitis is a severe and frequent blinding disease in horses which presents with auto-reactive invading T-cells, resulting in the destruction of the inner eye. Infiltration of inflammatory cells into the retina and vitreous is driven by currently unknown guidance cues, however surgical removal of the vitreous (vitrectomy) has proven therapeutically successful. Therefore, proteomic analyses of vitrectomy samples are likely to result in detection of proteins contributing to disease pathogenesis. Vitreous from healthy and ERU diseased horses were directly compared by quantitative mass spectrometry based on label-free quantification of peak intensities across samples. We found a significant upregulation of complement and coagulation cascades and downregulation of negative paracrine regulators of canonical Wnt signalling including the Wnt signalling inhibitors DKK3 and SFRP2. Based on immunohistochemistry, both proteins are expressed in equine retina and suggest localisation to retinal Müller glial cells (RMG), which may be the source cells for these proteins. Furthermore, retinal expression levels and patterns of DKK3 change in response to ERU. Since many other regulated proteins identified here are associated with RMG cells, these cells qualify as the prime responders to autoimmune triggers.

  4. Maintenance of adenomatous polyposis coli (APC)-mutant colorectal cancer is dependent on Wnt/beta-catenin signaling.

    Science.gov (United States)

    Scholer-Dahirel, Alix; Schlabach, Michael R; Loo, Alice; Bagdasarian, Linda; Meyer, Ronald; Guo, Ribo; Woolfenden, Steve; Yu, Kristine K; Markovits, Judit; Killary, Karen; Sonkin, Dmitry; Yao, Yung-Mae; Warmuth, Markus; Sellers, William R; Schlegel, Robert; Stegmeier, Frank; Mosher, Rebecca E; McLaughlin, Margaret E

    2011-10-11

    Persistent expression of certain oncogenes is required for tumor maintenance. This phenotype is referred to as oncogene addiction and has been clinically validated by anticancer therapies that specifically inhibit oncoproteins such as BCR-ABL, c-Kit, HER2, PDGFR, and EGFR. Identifying additional genes that are required for tumor maintenance may lead to new targets for anticancer drugs. Although the role of aberrant Wnt pathway activation in the initiation of colorectal cancer has been clearly established, it remains unclear whether sustained Wnt pathway activation is required for colorectal tumor maintenance. To address this question, we used inducible β-catenin shRNAs to temporally control Wnt pathway activation in vivo. Here, we show that active Wnt/β-catenin signaling is required for maintenance of colorectal tumor xenografts harboring APC mutations. Reduced tumor growth upon β-catenin inhibition was due to cell cycle arrest and differentiation. Upon reactivation of the Wnt/β-catenin pathway colorectal cancer cells resumed proliferation and reacquired a crypt progenitor phenotype. In human colonic adenocarcinomas, high levels of nuclear β-catenin correlated with crypt progenitor but not differentiation markers, suggesting that the Wnt/β-catenin pathway may also control colorectal tumor cell fate during the maintenance phase of tumors in patients. These results support efforts to treat human colorectal cancer by pharmacological inhibition of the Wnt/β-catenin pathway.

  5. Increased NF-κB Activity and Decreased Wnt/β-Catenin Signaling Mediate Reduced Osteoblast Differentiation and Function in ΔF508 Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Mice.

    Science.gov (United States)

    Le Henaff, Carole; Mansouri, Rafik; Modrowski, Dominique; Zarka, Mylène; Geoffroy, Valérie; Marty, Caroline; Tarantino, Nadine; Laplantine, Emmanuel; Marie, Pierre J

    2015-07-17

    The prevalent human ΔF508 mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) is associated with reduced bone formation and bone loss in mice. The molecular mechanisms by which the ΔF508-CFTR mutation causes alterations in bone formation are poorly known. In this study, we analyzed the osteoblast phenotype in ΔF508-CFTR mice and characterized the signaling mechanisms underlying this phenotype. Ex vivo studies showed that the ΔF508-CFTR mutation negatively impacted the differentiation of bone marrow stromal cells into osteoblasts and the activity of osteoblasts, demonstrating that the ΔF508-CFTR mutation alters both osteoblast differentiation and function. Treatment with a CFTR corrector rescued the abnormal collagen gene expression in ΔF508-CFTR osteoblasts. Mechanistic analysis revealed that NF-κB signaling and transcriptional activity were increased in mutant osteoblasts. Functional studies showed that the activation of NF-κB transcriptional activity in mutant osteoblasts resulted in increased β-catenin phosphorylation, reduced osteoblast β-catenin expression, and altered expression of Wnt/β-catenin target genes. Pharmacological inhibition of NF-κB activity or activation of canonical Wnt signaling rescued Wnt target gene expression and corrected osteoblast differentiation and function in bone marrow stromal cells and osteoblasts from ΔF508-CFTR mice. Overall, the results show that the ΔF508-CFTR mutation impairs osteoblast differentiation and function as a result of overactive NF-κB and reduced Wnt/β-catenin signaling. Moreover, the data indicate that pharmacological inhibition of NF-κB or activation of Wnt/β-catenin signaling can rescue the abnormal osteoblast differentiation and function induced by the prevalent ΔF508-CFTR mutation, suggesting novel therapeutic strategies to correct the osteoblast dysfunctions in cystic fibrosis.

  6. Signal Transduction Pathways of EMT Induced by TGF-β, SHH, and WNT and Their Crosstalks

    Science.gov (United States)

    Zhang, Jingyu; Tian, Xiao-Jun; Xing, Jianhua

    2016-01-01

    Epithelial-to-mesenchymal transition (EMT) is a key step in development, wound healing, and cancer development. It involves cooperation of signaling pathways, such as transformation growth factor-β (TGF-β), Sonic Hedgehog (SHH), and WNT pathways. These signaling pathways crosstalk to each other and converge to key transcription factors (e.g., SNAIL1) to initialize and maintain the process of EMT. The functional roles of multi-signaling pathway crosstalks in EMT are sophisticated and, thus, remain to be explored. In this review, we focused on three major signal transduction pathways that promote or regulate EMT in carcinoma. We discussed the network structures, and provided a brief overview of the current therapy strategies and drug development targeted to these three signal transduction pathways. Finally, we highlighted systems biology approaches that can accelerate the process of deconstructing complex networks and drug discovery. PMID:27043642

  7. Signal Transduction Pathways of EMT Induced by TGF-β, SHH, and WNT and Their Crosstalks.

    Science.gov (United States)

    Zhang, Jingyu; Tian, Xiao-Jun; Xing, Jianhua

    2016-03-28

    Epithelial-to-mesenchymal transition (EMT) is a key step in development, wound healing, and cancer development. It involves cooperation of signaling pathways, such as transformation growth factor-β (TGF-β), Sonic Hedgehog (SHH), and WNT pathways. These signaling pathways crosstalk to each other and converge to key transcription factors (e.g., SNAIL1) to initialize and maintain the process of EMT. The functional roles of multi-signaling pathway crosstalks in EMT are sophisticated and, thus, remain to be explored. In this review, we focused on three major signal transduction pathways that promote or regulate EMT in carcinoma. We discussed the network structures, and provided a brief overview of the current therapy strategies and drug development targeted to these three signal transduction pathways. Finally, we highlighted systems biology approaches that can accelerate the process of deconstructing complex networks and drug discovery.

  8. Signal Transduction Pathways of EMT Induced by TGF-β, SHH, and WNT and Their Crosstalks

    Directory of Open Access Journals (Sweden)

    Jingyu Zhang

    2016-03-01

    Full Text Available Epithelial-to-mesenchymal transition (EMT is a key step in development, wound healing, and cancer development. It involves cooperation of signaling pathways, such as transformation growth factor-β (TGF-β, Sonic Hedgehog (SHH, and WNT pathways. These signaling pathways crosstalk to each other and converge to key transcription factors (e.g., SNAIL1 to initialize and maintain the process of EMT. The functional roles of multi-signaling pathway crosstalks in EMT are sophisticated and, thus, remain to be explored. In this review, we focused on three major signal transduction pathways that promote or regulate EMT in carcinoma. We discussed the network structures, and provided a brief overview of the current therapy strategies and drug development targeted to these three signal transduction pathways. Finally, we highlighted systems biology approaches that can accelerate the process of deconstructing complex networks and drug discovery.

  9. The Notch intracellular domain integrates signals from Wnt, Hedgehog, TGFβ/BMP and hypoxia pathways.

    Science.gov (United States)

    Borggrefe, Tilman; Lauth, Matthias; Zwijsen, An; Huylebroeck, Danny; Oswald, Franz; Giaimo, Benedetto Daniele

    2016-02-01

    Notch signaling is a highly conserved signal transduction pathway that regulates stem cell maintenance and differentiation in several organ systems. Upon activation, the Notch receptor is proteolytically processed, its intracellular domain (NICD) translocates into the nucleus and activates expression of target genes. Output, strength and duration of the signal are tightly regulated by post-translational modifications. Here we review the intracellular post-translational regulation of Notch that fine-tunes the outcome of the Notch response. We also describe how crosstalk with other conserved signaling pathways like the Wnt, Hedgehog, hypoxia and TGFβ/BMP pathways can affect Notch signaling output. This regulation can happen by regulation of ligand, receptor or transcription factor expression, regulation of protein stability of intracellular key components, usage of the same cofactors or coregulation of the same key target genes. Since carcinogenesis is often dependent on at least two of these pathways, a better understanding of their molecular crosstalk is pivotal.

  10. Wnt/β-Catenin Signaling Mediated-UCH-L1 Expression in Podocytes of Diabetic Nephropathy

    Science.gov (United States)

    Zhang, Hongxia; Luo, Weili; Sun, Yonghong; Qiao, Yanchun; Zhang, Liying; Zhao, Zhilian; Lv, Shijun

    2016-01-01

    Increasing studies identified podocyte injury as a key early risk factor resulting in diabetic nephropathy (DN). The ubiquitin carboxy-terminal hydrolase 1 (UCH-L1) participates in podocyte differentiation and injury, which is elevated in the podocytes of a variety of nephritis. Whether UCH-L1 expression is positively related to podocyte injury of DN remains unclear. In this study, elevated expression of UCH-L1 and its intrinsic mechanism in high glucose (HG)-stimulated murine podocytes were investigated using western blot and real-time quantitative PCR. Kidney biopsies of DN patients and health individuals were stained by immunofluorescence (IF) method. The morphological and functional changes of podocytes were tested by F-actin staining and cell migration assay. Results demonstrated that HG induced upregulation of UCH-L1 and activation of the Wnt/β-catenin signaling pathway in podocytes. However, blocking of the Wnt pathway by dickkopf related protein 1 (DKK1) eliminated the above changes. Furthermore, IF staining confirmed that, compared with healthy individuals, the expression of UCH-L1 and β-catenin were obviously increased in kidney biopsy of DN patients. Overexpression of UCH-L1 remodeled its actin cytoskeleton, increased its cell migration and impacted its important proteins. All the findings manifested that Wnt/β-catenin/UCH-L1 may be a new potential therapy method in the treatment of DN in future. PMID:27571062

  11. Macrophage Wnt-Calcineurin-Flt1 signaling regulates mouse wound angiogenesis and repair.

    Science.gov (United States)

    Stefater, James A; Rao, Sujata; Bezold, Katie; Aplin, Alfred C; Nicosia, Roberto F; Pollard, Jeffrey W; Ferrara, Napoleone; Lang, Richard A

    2013-03-28

    The treatment of festering wounds is one of the most important aspects of medical care. Macrophages are important components of wound repair, both in fending off infection and in coordinating tissue repair. Here we show that macrophages use a Wnt-Calcineurin-Flt1 signaling pathway to suppress wound vasculature and delay repair. Conditional mutants deficient in both Wntless/GPR177, the secretory transporter of Wnt ligands, and CNB1, the essential component of the nuclear factor of activated T cells dephosporylation complex, displayed enhanced angiogenesis and accelerated repair. Furthermore, in myeloid-like cells, we show that noncanonical Wnt activates Flt1, a naturally occurring inhibitor of vascular endothelial growth factor-A-mediated angiogenesis, but only when calcineurin function is intact. Then, as expected, conditional deletion of Flt1 in macrophages resulted in enhanced wound angiogenesis and repair. These results are consistent with the published link between enhanced angiogenesis and enhanced repair, and establish novel therapeutic approaches for treatment of wounds.

  12. Maternal Mga is required for Wnt signaling and organizer formation in the early Xenopus embryo

    Institute of Scientific and Technical Information of China (English)

    Fei Gu; Huijuan Shi; Li Gao; Haiyan Zhang; Qinghua Tao

    2012-01-01

    Maternal Wnt11 is both necessary and sufficient for the formation of Spemann organizer in Xenopus embryo.Xnr3 and Siamois have been identified as the direct target genes of maternal Wnt11/β-catenin during organizer induction.The depletion of maternal XTcf3 resulted in the ectopic expression of Xnr3 and Siamois,suggesting the activity of β-catenin/XTcf3 is strictly regulated in the early Xenopus embryos.Here,we show that Xenopus mga (Xmga) is a maternal gene required for dorsal axis formation.Overexpression experiments indicate that mouse Mga potentiates the activity of β-catenin in the induction of organizer-specific genes.Depletion of maternal Xmga results in the dramatic decrease of the expression of organizer genes and ventralization phenotype,indicating that Xmga is required for β-catenin function and organizer formation.Depletion of XTcf3 cannot rescue organizer gene expression and axis formation in Xmga-depleted embryos,suggesting Xmga is downstream of XTcf3 during organizer induction.We conclude that maternal Xmga is critical for the function of β-catenin during organizer formation and dorsal development of Xenopus embryo.To our knowledge,this is a report for the first time to implicate Mga in regulating Wnt signaling.

  13. Neuronal target identification requires AHA-1-mediated fine-tuning of Wnt signaling in C. elegans.

    Directory of Open Access Journals (Sweden)

    Jingyan Zhang

    2013-06-01

    Full Text Available Electrical synaptic transmission through gap junctions is a vital mode of intercellular communication in the nervous system. The mechanism by which reciprocal target cells find each other during the formation of gap junctions, however, is poorly understood. Here we show that gap junctions are formed between BDU interneurons and PLM mechanoreceptors in C. elegans and the connectivity of BDU with PLM is influenced by Wnt signaling. We further identified two PAS-bHLH family transcription factors, AHA-1 and AHR-1, which function cell-autonomously within BDU and PLM to facilitate the target identification process. aha-1 and ahr-1 act genetically upstream of cam-1. CAM-1, a membrane-bound receptor tyrosine kinase, is present on both BDU and PLM cells and likely serves as a Wnt antagonist. By binding to a cis-regulatory element in the cam-1 promoter, AHA-1 enhances cam-1 transcription. Our study reveals a Wnt-dependent fine-tuning mechanism that is crucial for mutual target cell identification during the formation of gap junction connections.

  14. Wnt Signaling Prevents the Aβ Oligomer-Induced Mitochondrial Permeability Transition Pore Opening Preserving Mitochondrial Structure in Hippocampal Neurons

    Science.gov (United States)

    Arrázola, Macarena S.; Ramos-Fernández, Eva; Cisternas, Pedro; Ordenes, Daniela; Inestrosa, Nibaldo C.

    2017-01-01

    Alzheimer’s disease (AD) is a neurodegenerative disorder mainly known for synaptic impairment and neuronal cell loss, affecting memory processes. Beside these damages, mitochondria have been implicated in the pathogenesis of AD through the induction of the mitochondrial permeability transition pore (mPTP). The mPTP is a non-selective pore that is formed under apoptotic conditions, disturbing mitochondrial structure and thus, neuronal viability. In AD, Aβ oligomers (Aβos) favor the opening of the pore, activating mitochondria-dependent neuronal cell death cascades. The Wnt signaling activated through the ligand Wnt3a has been described as a neuroprotective signaling pathway against amyloid-β (Aβ) peptide toxicity in AD. However, the mechanisms by which Wnt signaling prevents Aβos-induced neuronal cell death are unclear. We proposed here to study whether Wnt signaling protects neurons earlier than the late damages in the progression of the disease, through the preservation of the mitochondrial structure by the mPTP inhibition. To study specific events related to mitochondrial permeabilization we performed live-cell imaging from primary rat hippocampal neurons, and electron microscopy to analyze the mitochondrial morphology and structure. We report here that Wnt3a prevents an Aβos-induced cascade of mitochondrial events that leads to neuronal cell death. This cascade involves (a) mPTP opening, (b) mitochondrial swelling, (c) mitochondrial membrane potential loss and (d) cytochrome c release, thus leading to neuronal cell death. Furthermore, our results suggest that the activation of the Wnt signaling prevents mPTP opening by two possible mechanisms, which involve the inhibition of mitochondrial GSK-3β and/or the modulation of mitochondrial hexokinase II levels and activity. This study suggests a possible new approach for the treatment of AD from a mitochondrial perspective, and will also open new lines of study in the field of Wnt signaling in neuroprotection

  15. The Tumor Suppressor BCL7B Functions in the Wnt Signaling Pathway.

    Directory of Open Access Journals (Sweden)

    Tomoko Uehara

    2015-01-01

    Full Text Available Human BCL7 gene family consists of BCL7A, BCL7B, and BCL7C. A number of clinical studies have reported that BCL7 family is involved in cancer incidence, progression, and development. Among them, BCL7B, located on chromosome 7q11.23, is one of the deleted genes in patients with Williams-Beuren syndrome. Although several studies have suggested that malignant diseases occurring in patients with Williams-Beuren syndrome are associated with aberrations in BCL7B, little is known regarding the function of this gene at the cellular level. In this study, we focused on bcl-7, which is the only homolog of BCL7 gene family in Caenorhabditis elegans, and analyzed bcl-7 deletion mutants. As a result, we found that bcl-7 is required for the asymmetric differentiation of epithelial seam cells, which have self-renewal properties as stem cells and divide asymmetrically through the WNT pathway. Distal tip cell development, which is regulated by the WNT pathway in Caenorhabditis elegans, was also affected in bcl-7-knockout mutants. Interestingly, bcl-7 mutants exhibited nuclear enlargement, reminiscent of the anaplastic features of malignant cells. Furthermore, in KATOIII human gastric cancer cells, BCL7B knockdown induced nuclear enlargement, promoted the multinuclei phenotype and suppressed cell death. In addition, this study showed that BCL7B negatively regulates the Wnt-signaling pathway and positively regulates the apoptotic pathway. Taken together, our data indicate that BCL7B/BCL-7 has some roles in maintaining the structure of nuclei and is involved in the modulation of multiple pathways, including Wnt and apoptosis. This study may implicate a risk of malignancies with BCL7B-deficiency, such as Williams-Beuren syndrome.

  16. Wnt/planar cell polarity signaling controls the anterior-posterior organization of monoaminergic axons in the brainstem.

    Science.gov (United States)

    Fenstermaker, Ali G; Prasad, Asheeta A; Bechara, Ahmad; Adolfs, Youri; Tissir, Fadel; Goffinet, Andre; Zou, Yimin; Pasterkamp, R Jeroen

    2010-11-24

    Monoaminergic neurons [serotonergic (5-HT) and dopaminergic (mdDA)] in the brainstem project axons along the anterior-posterior axis. Despite their important physiological functions and implication in disease, the molecular mechanisms that dictate the formation of these projections along the anterior-posterior axis remain unknown. Here we reveal a novel requirement for Wnt/planar cell polarity signaling in the anterior-posterior organization of the monoaminergic system. We find that 5-HT and mdDA axons express the core planar cell polarity components Frizzled3, Celsr3, and Vangl2. In addition, monoaminergic projections show anterior-posterior guidance defects in Frizzled3, Celsr3, and Vangl2 mutant mice. The only known ligands for planar cell polarity signaling are Wnt proteins. In culture, Wnt5a attracts 5-HT but repels mdDA axons, and Wnt7b attracts mdDA axons. However, mdDA axons from Frizzled3 mutant mice are unresponsive to Wnt5a and Wnt7b. Both Wnts are expressed in gradients along the anterior-posterior axis, consistent with their role as directional cues. Finally, Wnt5a mutants show transient anterior-posterior guidance defects in mdDA projections. Furthermore, we observe during development that the cell bodies of migrating descending 5-HT neurons eventually reorient along the direction of their axons. In Frizzled3 mutants, many 5-HT and mdDA neuron cell bodies are oriented abnormally along the direction of their aberrant axon projections. Overall, our data suggest that Wnt/planar cell polarity signaling may be a global anterior-posterior guidance mechanism that controls axonal and cellular organization beyond the spinal cord.

  17. Signaling components of the 1α,25(OH)2D3-dependent Pdia3 receptor complex are required for Wnt5a calcium-dependent signaling.

    Science.gov (United States)

    Doroudi, Maryam; Olivares-Navarrete, Rene; Hyzy, Sharon L; Boyan, Barbara D; Schwartz, Zvi

    2014-11-01

    Wnt5a and 1α,25(OH)2D3 are important regulators of endochondral ossification. In osteoblasts and growth plate chondrocytes, 1α,25(OH)2D3 initiates rapid effects via its membrane-associated receptor protein disulfide isomerase A3 (Pdia3) in caveolae, activating phospholipase A2 (PLA2)-activating protein (PLAA), calcium/calmodulin-dependent protein kinase II (CaMKII), and PLA2, resulting in protein kinase C (PKC) activation. Wnt5a initiates its calcium-dependent effects via intracellular calcium release, activating PKC and CaMKII. We investigated the requirement for components of the Pdia3 receptor complex in Wnt5a calcium-dependent signaling. We determined that Wnt5a signals through a CaMKII/PLA2/PGE2/PKC cascade. Silencing or blocking Pdia3, PLAA, or vitamin D receptor (VDR), and inhibition of calmodulin (CaM), CaMKII, or PLA2 inhibited Wnt5a-induced PKC activity. Wnt5a activated PKC in caveolin-1-silenced cells, but methyl-beta-cyclodextrin reduced its stimulatory effect. 1α,25(OH)2D3 reduced stimulatory effects of Wnt5a on PKC in a dose-dependent manner. In contrast, Wnt5a had a biphasic effect on 1α,25(OH)2D3-stimulated PKC activation; 50ng/ml Wnt5a caused a 2-fold increase in 1α,25(OH)2D3-stimulated PKC but higher Wnt5a concentrations reduced 1α,25(OH)2D3-stimulated PKC activation. Western blots showed that Wnt receptors Frizzled2 (FZD2) and Frizzled5 (FZD5), and receptor tyrosine kinase-like orphan receptor 2 (ROR2) were localized to caveolae. Blocking ROR2, but not FZD2 or FZD5, abolished the stimulatory effects of 1α,25(OH)2D3 on PKC and CaMKII. 1α,25(OH)2D3 membrane receptor complex components (Pdia3, PLAA, caveolin-1, CaM) interacted with Wnt5a receptors/co-receptors (ROR2, FZD2, FZD5) in immunoprecipitation studies, interactions that changed with either 1α,25(OH)2D3 or Wnt5a treatment. This study demonstrates that 1α,25(OH)2D3 and Wnt5a mediate their effects via similar receptor components and suggests that these pathways may interact.

  18. Dibenzocyclooctadiene lignans, gomisins J and N inhibit the Wnt/{beta}-catenin signaling pathway in HCT116 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyungsu; Lee, Kyung-Mi; Yoo, Ji-Hye; Lee, Hee Ju [Functional Food Center, Korea Institute of Science and Technology, Gangneung 210-340 (Korea, Republic of); Kim, Chul Young [Functional Food Center, Korea Institute of Science and Technology, Gangneung 210-340 (Korea, Republic of); College of Pharmacy, Hanyang University, Ansan 426-791 (Korea, Republic of); Nho, Chu Won, E-mail: cwnho@kist.re.kr [Functional Food Center, Korea Institute of Science and Technology, Gangneung 210-340 (Korea, Republic of)

    2012-11-16

    Graphical abstract: Schematic diagram of the possible molecular mechanism underlying the inhibition of the Wnt/{beta}-catenin signaling pathway and the induction of G0/G1-phase arrest by gomisins J and N, derived from the fruits of S. chinensis, in HCT116 human colon cancer cells. Highlights: Black-Right-Pointing-Pointer Gomisins J and N inhibited Wnt/{beta}-catenin signaling pathway in HCT116 cells. Black-Right-Pointing-Pointer Gomisins J and N disrupted the binding of {beta}-catenin to specific DNA sequences, TBE. Black-Right-Pointing-Pointer Gomisins J and N inhibited the HCT116 cell proliferation through G0/G1 phase arrest. Black-Right-Pointing-Pointer Gomisins J and N inhibited the expression of Cyc D1, a Wnt/{beta}-catenin target gene. -- Abstract: Here, we report that gomisin J and gomisin N, dibenzocyclooctadiene type lignans isolated from Schisandra chinensis, inhibit Wnt/{beta}-catenin signaling in HCT116 cells. Gomisins J and N appear to inhibit Wnt/{beta}-catenin signaling by disrupting the interaction between {beta}-catenin and its specific target DNA sequences (TCF binding elements, TBE) rather than by altering the expression of the {beta}-catenin protein. Gomisins J and N inhibit HCT116 cell proliferation by arresting the cell cycle at the G0/G1 phase. The G0/G1 phase arrest induced by gomisins J and N appears to be caused by a decrease in the expression of Cyclin D1, a representative target gene of the Wnt/{beta}-catenin signaling pathway, as well as Cdk2, Cdk4, and E2F-1. Therefore, gomisins J and N, the novel Wnt/{beta}-catenin inhibitors discovered in this study, may serve as potential agents for the prevention and treatment of human colorectal cancers.

  19. PGRN haploinsufficiency increased Wnt5a signaling in peripheral cells from frontotemporal lobar degeneration-progranulin mutation carriers.

    Science.gov (United States)

    Alquézar, Carolina; Esteras, Noemí; de la Encarnación, Ana; Alzualde, Ainhoa; Moreno, Fermín; López de Munain, Adolfo; Martín-Requero, Angeles

    2014-04-01

    Loss-of-function progranulin (PGRN) mutations have been identified as the major cause of frontotemporal lobar degeneration with TDP-43 protein inclusions (FTLD-TDP). Previously, we reported cell cycle-related alterations in lymphoblasts from FTLD-TDP patients, carrying the c.709-1G>A null PGRN mutation, suggesting aberrant cell cycle activation in affected neurons. Here we report that PGRN haploinsufficiency activates the extracellular signal-regulated protein kinases 1 and 2 pathway in a Ca(2+), protein kinase C-dependent, and pertussis toxin-sensitive manner. Addition of exogenous PGRN or conditioned medium from control cells normalized the response of PGRN-deficient lymphoblasts to serum activation. Our data indicated that noncanonical Wnt5a signaling might be overactivated by PGRN deficiency. We detected increased cellular and secreted levels of Wnt5a in PGRN-deficient lymphoblasts associated with enhanced phosphorylated calmodulin kinase II. Moreover, treatment of control cells with exogenous Wingless-type 5a (Wnt5a)-activated Ca(2+)/calmodulin kinase II (CaMKII), increased extracellular signal-regulated protein kinases 1 and 2 activity and cell proliferation up to the levels found in c.709-1G>A carrier cells. PGRN knockdown SH-SY5Y neuroblastoma cells also show enhanced Wnt5a content and signaling. Taken together, our results revealed an important role of Wnt signaling in FTLD-TDP pathology and suggest a novel target for therapeutic intervention.

  20. IL-1β-induced, matrix metalloproteinase-3-regulated proliferation of embryonic stem cell-derived odontoblastic cells is mediated by the Wnt5 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Ozeki, Nobuaki; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki; Kawai, Rie [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Kondo, Ayami [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan); Nakata, Kazuhiko [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Mogi, Makio, E-mail: makio@dpc.agu.ac.jp [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan)

    2014-10-15

    We previously established a method for differentiating induced pluripotent stem cells and embryonic stem (ES) cells into α2 integrin-positive odontoblast-like cells. We also reported that interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation and suppresses apoptosis in these cells, suggesting that MMP-3 plays a potentially unique physiological role in the regeneration of odontoblast-like cells. Here, we examined whether up-regulation of MMP-3 activity by IL-1β was mediated by Wnt signaling and led to increased proliferation of odontoblast-like cells. IL-1β increased mRNA and protein levels of Wnt5a, Wnt5b and the Wnt receptor Lrp5. Exogenous Wnt5a and Wnt5b were found to increase MMP-3 mRNA, protein and activity, and interestingly the rate of proliferation in these cells. Treatment with siRNAs against Wnt5a, Wnt5b and Lrp5 suppressed the IL-1β-induced increase in MMP-3 expression and suppressed cell proliferation, an effect rescued by application of exogenous Wnt5. These results demonstrate the sequential involvement of Wnt5, Lrp5 and MMP-3 in effecting IL-1β-induced proliferation of ES cell-derived odontoblast-like cells. - Highlights: • IL-1β induces Wnt5, Lrp5/Fzd9 and MMP-3 in ES cell-derived odontoblast-like cells. • IL-1β-induced Wnt5 expression results in increased cell proliferation. • Exogenous Wnt5 increases MMP-3 activity and cell proliferation. • Exogenous Wnt5 rescues IL-1β-driven proliferation with anti-Wnt5 siRNA suppression. • IL-1β-induced cell proliferation involves Wnt5, Lrp5, and MMP-3 sequentially.

  1. Ligand-independent canonical Wnt activity in canine mammary tumor cell lines associated with aberrant LEF1 expression

    NARCIS (Netherlands)

    Gracanin, Ana; Timmermans-Sprang, Elpetra P M; van Wolferen, Monique E; Rao, Nagesha A S; Grizelj, Juraj; Vince, Silvijo; Hellmen, Eva; Mol, Jan A

    2014-01-01

    Pet dogs very frequently develop spontaneous mammary tumors and have been suggested as a good model organism for breast cancer research. In order to obtain an insight into underlying signaling mechanisms during canine mammary tumorigenesis, in this study we assessed the incidence and the mechanism o

  2. Wnt signaling mediates experience-related regulation of synapse numbers and mossy fiber connectivities in the adult hippocampus.

    Science.gov (United States)

    Gogolla, Nadine; Galimberti, Ivan; Deguchi, Yuichi; Caroni, Pico

    2009-05-28

    We investigated how experience regulates the structure of a defined neuronal circuit in adult mice. Enriched environment (EE) produced a robust and reversible increase in hippocampal stratum lucidum synapse numbers, mossy fiber terminal (LMT) numbers, and spine plus synapse densities at LMTs, whereas a distinct mechanism depending on Rab3a promoted LMT volume growth. In parallel, EE increased postsynaptic CA3 pyramidal neuron Wnt7a/b levels. Inhibiting Wnt signaling through locally applied sFRP-1 suppressed the effects of EE on synapse numbers and further reduced synapse numbers in control mice. Wnt7 applied to CA3 mimicked the effects of EE on synapse and LMT numbers. CA3 Wnt7a/b levels were enhanced by excitatory activity and reduced by sFRP-1. Synapse numbers and Wnt7a/b levels peaked in mice aged 6-12 months; a decline in aged mice was reversed by EE. Therefore, behavioral experience specifically regulates adult global stratum lucidum synapse numbers and hippocampal network structure through Wnt signaling.

  3. Combined Wnt/β-Catenin, Met, and CXCL12/CXCR4 Signals Characterize Basal Breast Cancer and Predict Disease Outcome

    Directory of Open Access Journals (Sweden)

    Jane D. Holland

    2013-12-01

    Full Text Available Prognosis for patients with estrogen-receptor (ER-negative basal breast cancer is poor, and chemotherapy is currently the best therapeutic option. We have generated a compound-mutant mouse model combining the activation of β-catenin and HGF (Wnt-Met signaling, which produced rapidly growing basal mammary gland tumors. We identified the chemokine system CXCL12/CXCR4 as a crucial driver of Wnt-Met tumors, given that compound-mutant mice also deficient in the CXCR4 gene were tumor resistant. Wnt-Met activation rapidly expanded a population of cancer-propagating cells, in which the two signaling systems control different functions, self-renewal and differentiation. Molecular therapy targeting Wnt, Met, and CXCR4 in mice significantly delayed tumor development. The expression of a Wnt-Met 322 gene signature was found to be predictive of poor survival of human patients with ER-negative breast cancers. Thus, targeting CXCR4 and its upstream activators, Wnt and Met, might provide an efficient strategy for breast cancer treatment.

  4. C. elegans LIN-18 is a Ryk ortholog and functions in parallel to LIN-17/Frizzled in Wnt signaling.

    Science.gov (United States)

    Inoue, Takao; Oz, Helieh S; Wiland, Debra; Gharib, Shahla; Deshpande, Rashmi; Hill, Russell J; Katz, Wendy S; Sternberg, Paul W

    2004-09-17

    Wnt proteins are intercellular signals that regulate various aspects of animal development. In Caenorhabditis elegans, mutations in lin-17, a Frizzled-class Wnt receptor, and in lin-18 affect cell fate patterning in the P7.p vulval lineage. We found that lin-18 encodes a member of the Ryk/Derailed family of tyrosine kinase-related receptors, recently found to function as Wnt receptors. Members of this family have nonactive kinase domains. The LIN-18 kinase domain is dispensable for LIN-18 function, while the Wnt binding WIF domain is required. We also found that Wnt proteins LIN-44, MOM-2, and CWN-2 redundantly regulate P7.p patterning. Genetic interactions indicate that LIN-17 and LIN-18 function independently of each other in parallel pathways, and different ligands display different receptor specificities. Thus, two independent Wnt signaling pathways, one employing a Ryk receptor and the other a Frizzled receptor, function in parallel to regulate cell fate patterning in the C. elegans vulva.

  5. Combined Wnt/β-catenin, Met, and CXCL12/CXCR4 signals characterize basal breast cancer and predict disease outcome.

    Science.gov (United States)

    Holland, Jane D; Györffy, Balázs; Vogel, Regina; Eckert, Klaus; Valenti, Giovanni; Fang, Liang; Lohneis, Philipp; Elezkurtaj, Sefer; Ziebold, Ulrike; Birchmeier, Walter

    2013-12-12

    Prognosis for patients with estrogen-receptor (ER)-negative basal breast cancer is poor, and chemotherapy is currently the best therapeutic option. We have generated a compound-mutant mouse model combining the activation of β-catenin and HGF (Wnt-Met signaling), which produced rapidly growing basal mammary gland tumors. We identified the chemokine system CXCL12/CXCR4 as a crucial driver of Wnt-Met tumors, given that compound-mutant mice also deficient in the CXCR4 gene were tumor resistant. Wnt-Met activation rapidly expanded a population of cancer-propagating cells, in which the two signaling systems control different functions, self-renewal and differentiation. Molecular therapy targeting Wnt, Met, and CXCR4 in mice significantly delayed tumor development. The expression of a Wnt-Met 322 gene signature was found to be predictive of poor survival of human patients with ER-negative breast cancers. Thus, targeting CXCR4 and its upstream activators, Wnt and Met, might provide an efficient strategy for breast cancer treatment.

  6. Efficacy of Mesenchymal Stem Cells in Suppression of Hepatocarcinorigenesis in Rats: Possible Role of Wnt Signaling

    LENUS (Irish Health Repository)

    Abdel Aziz, Mohamed T

    2011-05-05

    Abstract Background The present study was conducted to evaluate the tumor suppressive effects of bone marrow derived mesenchymal stem cells (MSCs) in an experimental hepatocellular carcinoma (HCC) model in rats and to investigate the possible role of Wnt signaling in hepato-carcinogenesis. Methods Ninety rats were included in the study and were divided equally into: Control group, rats which received MSCs only, rats which received MSCs vehicle only, HCC group induced by diethylnitroseamine (DENA) and CCl 4 , rats which received MSCs after HCC induction, rats which received MSCs before HCC induction. Histopathological examination and gene expression of Wnt signaling target genes by real time, reverse transcription-polymerase chain reaction (RT-PCR) in rat liver tissue, in addition to serum levels of ALT, AST and alpha fetoprotein were performed in all groups. Results Histopathological examination of liver tissue from animals which received DENA-CCl4 only, revealed the presence of anaplastic carcinoma cells and macro-regenerative nodules type II with foci of large and small cell dysplasia. Administration of MSCs into rats after induction of experimental HCC improved the histopathological picture which showed minimal liver cell damage, reversible changes, areas of cell drop out filled with stem cells. Gene expression in rat liver tissue demonstrated that MSCs downregulated β-catenin, proliferating cell nuclear antigen (PCNA), cyclin D and survivin genes expression in liver tissues after HCC induction. Amelioration of the liver status after administration of MSCs has been inferred by the significant decrease of ALT, AST and Alpha fetoprotein serum levels. Administration of MSCs before HCC induction did not show any tumor suppressive or protective effect. Conclusions Administration of MSCs in chemically induced HCC has tumor suppressive effects as evidenced by down regulation of Wnt signaling target genes concerned with antiapoptosis, mitogenesis, cell proliferation

  7. Cyclin G2 suppresses estrogen-mediated osteogenesis through inhibition of Wnt/β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Jinlan Gao

    Full Text Available Estrogen plays an important role in the maintenance of bone formation, and deficiency in the production of estrogen is directly linked to postmenopausal osteoporosis. To date, the underlying mechanisms of estrogen-mediated osteogenic differentiation are not well understood. In this study, a pluripotent mesenchymal precursor cell line C2C12 was used to induce osteogenic differentiation and subjected to detection of gene expressions or to manipulation of cyclin G2 expressions. C57BL/6 mice were used to generate bilateral ovariectomized and sham-operated mice for analysis of bone mineral density and protein expression. We identified cyclin G2, an unconventional member of cyclin, is involved in osteoblast differentiation regulated by estrogen in vivo and in vitro. In addition, the data showed that ectopic expression of cyclin G2 suppressed expression of osteoblast transcription factor Runx2 and osteogenic differentiation marker genes, as well as ALP activity and in vitro extracellular matrix mineralization. Mechanistically, Wnt/β-catenin signaling pathway is essential for cyclin G2 to inhibit osteogenic differentiation. To the best of our knowledge, the current study presents the first evidence that cyclin G2 serves as a negative regulator of both osteogenesis and Wnt/β-catenin signaling. Most importantly, the basal and 17β-estradiol-induced osteogenic differentiation was restored by overexpression of cyclin G2. These results taken together suggest that cyclin G2 may function as an endogenous suppressor of estrogen-induced osteogenic differentiation through inhibition of Wnt/β-catenin signaling.

  8. Efficacy of Mesenchymal Stem Cells in Suppression of Hepatocarcinorigenesis in Rats: Possible Role of Wnt Signaling

    Directory of Open Access Journals (Sweden)

    Sabry Dina

    2011-05-01

    Full Text Available Abstract Background The present study was conducted to evaluate the tumor suppressive effects of bone marrow derived mesenchymal stem cells (MSCs in an experimental hepatocellular carcinoma (HCC model in rats and to investigate the possible role of Wnt signaling in hepato-carcinogenesis. Methods Ninety rats were included in the study and were divided equally into: Control group, rats which received MSCs only, rats which received MSCs vehicle only, HCC group induced by diethylnitroseamine (DENA and CCl4, rats which received MSCs after HCC induction, rats which received MSCs before HCC induction. Histopathological examination and gene expression of Wnt signaling target genes by real time, reverse transcription-polymerase chain reaction (RT-PCR in rat liver tissue, in addition to serum levels of ALT, AST and alpha fetoprotein were performed in all groups. Results Histopathological examination of liver tissue from animals which received DENA-CCl4 only, revealed the presence of anaplastic carcinoma cells and macro-regenerative nodules type II with foci of large and small cell dysplasia. Administration of MSCs into rats after induction of experimental HCC improved the histopathological picture which showed minimal liver cell damage, reversible changes, areas of cell drop out filled with stem cells. Gene expression in rat liver tissue demonstrated that MSCs downregulated β-catenin, proliferating cell nuclear antigen (PCNA, cyclin D and survivin genes expression in liver tissues after HCC induction. Amelioration of the liver status after administration of MSCs has been inferred by the significant decrease of ALT, AST and Alpha fetoprotein serum levels. Administration of MSCs before HCC induction did not show any tumor suppressive or protective effect. Conclusions Administration of MSCs in chemically induced HCC has tumor suppressive effects as evidenced by down regulation of Wnt signaling target genes concerned with antiapoptosis, mitogenesis, cell

  9. Functional Consequences of 17q21.31/WNT3-WNT9B Amplification in hPSCs with Respect to Neural Differentiation

    Directory of Open Access Journals (Sweden)

    Chun-Ting Lee

    2015-02-01

    Full Text Available Human pluripotent stem cell (hPSC lines exhibit repeated patterns of genetic variation, which can alter in vitro properties as well as suitability for clinical use. We examined associations between copy-number variations (CNVs on chromosome 17 and hPSC mesodiencephalic dopaminergic (mDA differentiation. Among 24 hPSC lines, two karyotypically normal lines, BG03 and CT3, and BG01V2, with trisomy 17, exhibited amplification of the WNT3/WNT9B region and rapid mDA differentiation. In hPSC lines with amplified WNT3/WNT9B, basic fibroblast growth factor (bFGF signaling through mitogen-activated protein kinase (MAPK/ERK amplifies canonical WNT signaling by phosphorylating LRP6, resulting in enhanced undifferentiated proliferation. When bFGF is absent, noncanonical WNT signaling becomes dominant due to upregulation of SIAH2, enhancing JNK signaling and promoting loss of pluripotency. When bFGF is present during mDA differentiation, stabilization of canonical WNT signaling causes upregulation of LMX1A and mDA induction. Therefore, CNVs in 17q21.31, a “hot spot” for genetic variation, have multiple and complex effects on hPSC cellular phenotype.

  10. Polycyclic aromatic hydrocarbons and dibutyl phthalate disrupt dorsal-ventral axis determination via the Wnt/{beta}-catenin signaling pathway in zebrafish embryos

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    Fairbairn, Elise A., E-mail: efairbairn@ucdavis.edu [University of California Davis, Bodega Marine Laboratory, P.O. Box 247, Bodega Bay, CA 94923 (United States); Bonthius, Jessica, E-mail: jessica.bonthius@gmail.com [University of California Davis, Bodega Marine Laboratory, P.O. Box 247, Bodega Bay, CA 94923 (United States); Cherr, Gary N., E-mail: gncherr@ucdavis.edu [University of California Davis, Bodega Marine Laboratory, P.O. Box 247, Bodega Bay, CA 94923 (United States); Department of Environmental Toxicology, University of California Davis, Davis, CA 95616 (United States); Department of Nutrition, University of California Davis, Davis, CA 95616 (United States)

    2012-11-15

    The canonical Wnt/{beta}-catenin signaling pathway is critical during early teleost development for establishing the dorsal-ventral axis. Within this pathway, GSK-3{beta}, a key regulatory kinase in the Wnt pathway, regulates {beta}-catenin degradation and thus the ability of {beta}-catenin to enter nuclei, where it can activate expression of genes that have been linked to the specification of the dorsal-ventral axis. In this study, we describe the morphological abnormalities that resulted in zebrafish embryos when axis determination was disrupted by environmental contaminants. These abnormalities were linked to abnormal nuclear accumulation of {beta}-catenin. Furthermore, we demonstrated that the developmental abnormalities and altered nuclear {beta}-catenin accumulation occurred when embryos were exposed to commercial GSK-3{beta} inhibitors. Zebrafish embryos were exposed to commercially available GSK-3 inhibitors (GSK-3 Inhibitor IX and 1-azakenpaullone), or common environmental contaminants (dibutyl phthalate or the polycyclic aromatic hydrocarbons phenanthrene and fluorene) from the 2 to 8-cell stage through the mid-blastula transition (MBT). These embryos displayed morphological abnormalities at 12.5 h post-fertilization (hpf) that were comparable to embryos exposed to lithium chloride (LiCl) (300 mM LiCl for 10 min, prior to the MBT), a classic disruptor of embryonic axis determination. Whole-mount immunolabeling and laser scanning confocal microscopy were used to localize {beta}-catenin. The commercial GSK-3 Inhibitors as well as LiCl, dibutyl phthalate, fluorene and phenanthrene all induced an increase in the levels of nuclear {beta}-catenin throughout the embryo, indicating that the morphological abnormalities were a result of disruption of Wnt/{beta}-catenin signaling during dorsal-ventral axis specification. The ability of environmental chemicals to directly or indirectly target GSK-3{beta} was assessed. Using Western blot analysis, the ability of these

  11. Abnormal Wnt and PI3Kinase signaling in the malformed intestine of lama5 deficient mice.

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    Léa Ritié

    Full Text Available Laminins are major constituents of basement membranes and are essential for tissue homeostasis. Laminin-511 is highly expressed in the intestine and its absence causes severe malformation of the intestine and embryonic lethality. To understand the mechanistic role of laminin-511 in tissue homeostasis, we used RNA profiling of embryonic intestinal tissue of lama5 knockout mice and identified a lama5 specific gene expression signature. By combining cell culture experiments with mediated knockdown approaches, we provide a mechanistic link between laminin α5 gene deficiency and the physiological phenotype. We show that laminin α5 plays a crucial role in both epithelial and mesenchymal cell behavior by inhibiting Wnt and activating PI3K signaling. We conclude that conflicting signals are elicited in the absence of lama5, which alter cell adhesion, migration as well as epithelial and muscle differentiation. Conversely, adhesion to laminin-511 may serve as a potent regulator of known interconnected PI3K/Akt and Wnt signaling pathways. Thus deregulated adhesion to laminin-511 may be instrumental in diseases such as human pathologies of the gut where laminin-511 is abnormally expressed as it is shown here.

  12. Wnt11b is involved in cilia-mediated symmetry breakage during Xenopus left-right development.

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    Peter Walentek

    Full Text Available Breakage of bilateral symmetry in amphibian embryos depends on the development of a ciliated epithelium at the gastrocoel roof during early neurulation. Motile cilia at the gastrocoel roof plate (GRP give rise to leftward flow of extracellular fluids. Flow is required for asymmetric gene expression and organ morphogenesis. Wnt signaling has previously been involved in two steps, Wnt/ß-catenin mediated induction of Foxj1, a regulator of motile cilia, and Wnt/planar cell polarity (PCP dependent cilia polarization to the posterior pole of cells. We have studied Wnt11b in the context of laterality determination, as this ligand was reported to activate canonical and non-canonical Wnt signaling. Wnt11b was found to be expressed in the so-called superficial mesoderm (SM, from which the GRP derives. Surprisingly, Foxj1 was only marginally affected in loss-of-function experiments, indicating that another ligand acts in this early step of laterality specification. Wnt11b was required, however, for polarization of GRP cilia and GRP morphogenesis, in line with the known function of Wnt/PCP in cilia-driven leftward flow. In addition Xnr1 and Coco expression in the lateral-most GRP cells, which sense flow and generate the first asymmetric signal, was attenuated in morphants, involving Wnt signaling in yet another process related to symmetry breakage in Xenopus.

  13. WNT/Frizzled signalling: receptor-ligand selectivity with focus on FZD-G protein signalling and its physiological relevance: IUPHAR Review 3.

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    Dijksterhuis, J P; Petersen, J; Schulte, G

    2014-03-01

    The wingless/int1 (WNT)/Frizzled (FZD) signalling pathway controls numerous cellular processes such as proliferation, differentiation, cell-fate decisions, migration and plays a crucial role during embryonic development. Nineteen mammalian WNTs can bind to 10 FZDs thereby activating different downstream pathways such as WNT/β-catenin, WNT/planar cell polarity and WNT/Ca(2+) . However, the mechanisms of signalling specification and the involvement of heterotrimeric G proteins are still unclear. Disturbances in the pathways can lead to various diseases ranging from cancer, inflammatory diseases to metabolic and neurological disorders. Due to the presence of seven-transmembrane segments, evidence for coupling between FZDs and G proteins and substantial structural differences in class A, B or C GPCRs, FZDs were grouped separately in the IUPHAR GPCR database as the class FZD within the superfamily of GPCRs. Recently, important progress has been made pointing to a direct activation of G proteins after WNT stimulation. WNT/FZD and G protein coupling remain to be fully explored, although the basic observation supporting the nature of FZDs as GPCRs is compelling. Because the involvement of different (i) WNTs; (ii) FZDs; and (iii) intracellular binding partners could selectively affect signalling specification, in this review we present the current understanding of receptor/ligand selectivity of FZDs and WNTs. We pinpoint what is known about signalling specification and the physiological relevance of these interactions with special emphasis on FZD-G protein interactions.

  14. PLD1 regulates Xenopus convergent extension movements by mediating Frizzled7 endocytosis for Wnt/PCP signal activation.

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    Lee, Hyeyoon; Lee, Seung Joon; Kim, Gun-Hwa; Yeo, Inchul; Han, Jin-Kwan

    2016-03-01

    Phospholipase D (PLD) is involved in the regulation of receptor-associated signaling, cell movement, cell adhesion and endocytosis. However, its physiological role in vertebrate development remains poorly understood. In this study, we show that PLD1 is required for the convergent extension (CE) movements during Xenopus gastrulation by activating Wnt/PCP signaling. Xenopus PLD1 protein is specifically enriched in the dorsal region of Xenopus gastrula embryo and loss or gain-of-function of PLD1 induce defects in gastrulation and CE movements. These defective phenotypes are due to impaired regulation of Wnt/PCP signaling pathway. Biochemical and imaging analysis using Xenopus tissues reveal that PLD1 is required for Fz7 receptor endocytosis upon Wnt11 stimulation. Moreover, we show that Fz7 endocytosis depends on dynamin and regulation of GAP activity of dynamin by PLD1 via its PX domain is crucial for this process. Taken together, our results suggest that PLD1 acts as a new positive mediator of Wnt/PCP signaling by promoting Wnt11-induced Fz7 endocytosis for precise regulation of Xenopus CE movements.

  15. Sequential antagonism of early and late Wnt-signaling by zebrafish colgate promotes dorsal and anterior fates.

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    Nambiar, Roopa M; Henion, Paul D

    2004-03-01

    The establishment of the vertebrate body plan involves patterning of the ectoderm, mesoderm, and endoderm along the dorsoventral and antero-posterior axes. Interactions among numerous signaling molecules from several multigene families, including Wnts, have been implicated in regulating these processes. Here we provide evidence that the zebrafish colgate(b382) (col) mutation results in increased Wnt signaling that leads to defects in dorsal and anterior development. col mutants display early defects in dorsoventral patterning manifested by a decrease in the expression of dorsal shield-specific markers and ectopic expression of ventrolaterally expressed genes during gastrulation. In addition to these early patterning defects, col mutants display a striking regional posteriorization within the neuroectoderm, resulting in a reduction in anterior fates and an expansion of posterior fates within the forebrain and midbrain-hindbrain regions. We are able to correlate these phenotypes to the overactivation of Wnt signaling in col mutants. The early dorsal and anterior patterning phenotypes of the col mutant embryos are selectively rescued by inactivation of Wnt8 function by morpholino translational interference. In contrast, the regionalized neuroectoderm posterioriorization phenotype is selectively rescued by morpholino-mediated inactivation of Wnt8b. These results suggest that col-mediated antagonism of early and late Wnt-signaling activity during gastrulation is normally required sequentially for both early dorsoventral patterning and the specification and patterning of regional fates within the anterior neuroectoderm.

  16. Long-Term Expansion, Enhanced Chondrogenic Potential, and Suppression of Endochondral Ossification of Adult Human MSCs via WNT Signaling Modulation

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    Roberto Narcisi

    2015-03-01

    Full Text Available Mesenchymal stem cells (MSCs are a potential source of chondrogenic cells for the treatment of cartilage disorders, but loss of chondrogenic potential during in vitro expansion and the propensity of cartilage to undergo hypertrophic maturation impede their therapeutic application. Here we report that the signaling protein WNT3A, in combination with FGF2, supports long-term expansion of human bone marrow-derived MSCs. The cells retained their chondrogenic potential and other phenotypic and functional properties of multipotent MSCs, which were gradually lost in the absence of WNT3A. Moreover, we discovered that endogenous WNT signals are the main drivers of the hypertrophic maturation that follows chondrogenic differentiation. Inhibition of WNT signals during differentiation prevented calcification and maintained cartilage properties following implantation in a mouse model. By maintaining potency during expansion and preventing hypertrophic maturation following differentiation, the modulation of WNT signaling removes two major obstacles that impede the clinical application of MSCs in cartilage repair.

  17. Effect of micro-nano-hybrid structured hydroxyapatite bioceramics on osteogenic and cementogenic differentiation of human periodontal ligament stem cell via Wnt signaling pathway

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    Mao LX

    2015-11-01

    -related protein 5 (LRP5 and β-catenin, which are the key genes of canonical Wnt signaling. Moreover, the stimulatory effect on ALP activity and osteogenic and cementogenic gene expression, including that of ALP, OCN, CAP, CEMP, and Runx2 of mnHA bioceramics could be repressed by canonical Wnt signaling inhibitor dickkopf1 (Dkk1. The results suggested that the HA bioceramics with mnHA could act as promising grafts for periodontal tissue regeneration.Keywords: surface topography, periodontal ligament stem cells, Wnt signaling pathway, bioceramics, periodontal reconstruction

  18. Methylation of the Wnt Signaling Antagonist, Wnt Inhibitory Factor 1 and Dickkopf-1 Genes in Acute Myeloid Leukemia at the Time of Diagnosis

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    Ali Ghasemi

    2016-01-01

    Full Text Available Background In acute myeloid leukemia (AML, a large number of tumor suppressor genes are silenced through DNA methylation such as CDKN2B and p73. Wnt inhibitory factor 1 (WIF1 and Dickkopf-1 (DKK-1 are negative regulator of the Wnt signaling pathway. Objectives In the present study, we studied the methylation status of WIF1 and DKK-1 genes in AML patients. Patients and Methods In this case-control study, blood samples from 120 AML patients and 25 healthy control subjects collected, isolated DNA was treated with sodium bisulphite and examined by methylation specific PCR (MS-PCR with primers specific for methylated and unmethylated sequences of the WIF1 and DKK-1 genes. Results The frequency of aberrant hypermethylation of WIF1 and DKK-1 genes in AML patients determined 35% (42/120 and 28.3% (34/120, respectively. In addition, for all subjects in control group, methylation of WIF1 and DKK-1 genes were negative. Patients with M0 subtype of French-American-British (FAB-AML had the highest incidence of hypermethylation of WIF1 (P = 0.003 and DKK-1 (P = 0.005 genes. Conclusions The present study showed that, like many solid tumors, WIF1 and DKK-1 genes methylation also occurs in AML. The study of other antagonists of Wnt signaling pathway are recommended.

  19. LGR5 is expressed by Ewing sarcoma and potentiates Wnt/β-catenin signaling

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    Christopher A Scannell

    2013-04-01

    Full Text Available Ewing sarcoma (ES is an aggressive bone and soft tissue tumor of putative stem cell origin that predominantly occurs in children and young adults. Although most patients with localized ES can be cured with intensive therapy, the clinical course is variable and up to one third of patients relapse following initial remission. Unfortunately, little is yet known about the biologic features that distinguish low-risk from high-risk disease or the mechanisms of ES disease progression. Recent reports have suggested that putative cancer stem cells exist in ES and may contribute to an aggressive phenotype. The cell surface receptor LGR5 (leucine-rich repeat-containing G-protein coupled receptor 5 is a somatic stem cell marker that functions as an oncogene in several human cancers, most notably colorectal carcinoma. LGR5 is a receptor for the R-spondin (RSPO family of ligands and RSPO-mediated activation of LGR5 potentiates Wnt/β-catenin signaling, contributing to stem cell proliferation and self-renewal. Given its presumed stem cell origin, we investigated whether LGR5 contributes to ES pathogenesis. We found that LGR5 is expressed by ES and that its expression is relatively increased in cells and tumors that display a more aggressive phenotype. In particular, LGR5 expression was increased in putative cancer stem cells. We also found that neural crest-derived stem cells express LGR5, raising the possibility that expression of LGR5 may be a feature of ES cells of origin. LGR5-high ES cells showed nuclear localization of ß-catenin and robust activation of TCF-reporter activity when exposed to Wnt ligand and this was potentiated by RSPO. However, modulation of LGR5 or exposure to RSPO had no impact on proliferation confirming that Wnt/ β-catenin signaling in ES cells does not recapitulate signaling in epithelial cells. Together these studies show that the RSPO-LGR5-WNT- β-catenin axis is present and active in ES and may contribute to tumor pathogenesis.

  20. Avian facial morphogenesis is regulated by c-Jun N-terminal kinase/planar cell polarity (JNK/PCP) wingless-related (WNT) signaling.

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    Geetha-Loganathan, Poongodi; Nimmagadda, Suresh; Fu, Katherine; Richman, Joy M

    2014-08-29

    Wingless-related proteins (WNTs) regulate extension of the central axis of the vertebrate embryo (convergent extension) as well as morphogenesis of organs such as limbs and kidneys. Here, we asked whether WNT signaling directs facial morphogenesis using a targeted approach in chicken embryos. WNT11 is thought to mainly act via β-catenin-independent pathways, and little is known about its role in craniofacial development. RCAS::WNT11 retrovirus was injected into the maxillary prominence, and the majority of embryos developed notches in the upper beak or the equivalent of cleft lip. Three-dimensional morphometric analysis revealed that WNT11 prevented lengthening of the maxillary prominence, which was due in part to decreased proliferation. We next determined, using a series of luciferase reporters, that WNT11 strongly induced JNK/planar cell polarity signaling while repressing the β-catenin-mediated pathway. The activation of the JNK-ATF2 reporter was mediated by the DEP domain of Dishevelled. The impacts of altered signaling on the mesenchyme were assessed by implanted Wnt11- or Wnt3a-expressing cells (activates β-catenin pathway) into the maxillary prominence or by knocking down endogenous WNT11 with RNAi. Host cells were attracted to Wnt11 donor cells. In contrast, cells exposed to Wnt3a or the control cells did not migrate. Cells in which endogenous WNT11 was knocked down were more oriented and shorter than those exposed to exogenous WNT11. The data suggest that JNK/planar cell polarity WNT signaling operates in the face to regulate several morphogenetic events leading to lip fusion.

  1. Wnt/beta-catenin signaling down-regulates N-acetylglucosaminyltransferase III expression: the implications of two mutually exclusive pathways for regulation.

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    Xu, Qingsong; Akama, Ryota; Isaji, Tomoya; Lu, Yingying; Hashimoto, Hirokazu; Kariya, Yoshinobu; Fukuda, Tomohiko; Du, Yuguang; Gu, Jianguo

    2011-02-11

    In previous studies, we reported that N-acetylglucosaminyltransferase III (GnT-III) activity and the enzyme product, bisected N-glycans, both were induced in cells cultured under dense conditions in an E-cadherin-dependent manner (Iijima, J., Zhao, Y., Isaji, T., Kameyama, A., Nakaya, S., Wang, X., Ihara, H., Cheng, X., Nakagawa, T., Miyoshi, E., Kondo, A., Narimatsu, H., Taniguchi, N., and Gu, J. (2006) J. Biol. Chem. 281, 13038-13046). Furthermore, we found that α-catenin, a component of the E-cadherin-catenin complex, was also required for this induction (Akama, R., Sato, Y., Kariya, Y., Isaji, T., Fukuda, T., Lu, L., Taniguchi, N., Ozawa, M., and Gu, J. (2008) Proteomics 8, 3221-3228). To further explore the molecular mechanism of this regulation, the roles of β-catenin, an essential molecule in both cadherin-mediated cell adhesion and canonical Wnt signaling, were investigated. Unexpectedly, shRNA knockdown of β-catenin resulted in a dramatic increase in GnT-III expression and its product, the bisected N-glycans, which was confirmed by RT-PCR and GnT-III activity and by E4-PHA lectin blot analysis. The induction of GnT-III expression increased bisecting GlcNAc residues on β1 integrin, which led to down-regulation of integrin-mediated cell adhesion and cell migration. Immunostaining showed that nuclear localization of β-catenin was greatly suppressed; intriguingly, the knockdown of β-catenin in the nuclei was more effective than that in cell-cell contacts in the knockdown cells, which was also confirmed by Western blot analysis. Stimulation of the Wnt signaling pathway by the addition of exogenous Wnt3a or BIO, a GSK-3β inhibitor, consistently and significantly inhibited GnT-III expression and its products. Conversely, the inhibition of β-catenin translocation into the nuclei increased GnT-III activation. Taken together, the results of the present study are the first to clearly demonstrate that GnT-III expression may be precisely regulated by the

  2. Neuronal RING finger protein 11 (RNF11 regulates canonical NF-κB signaling

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    Pranski Elaine L

    2012-04-01

    Full Text Available Abstract Background The RING domain-containing protein RING finger protein 11 (RNF11 is a member of the A20 ubiquitin-editing protein complex and modulates peripheral NF-κB signaling. RNF11 is robustly expressed in neurons and colocalizes with a population of α-synuclein-positive Lewy bodies and neurites in Parkinson disease patients. The NF-κB pathway has an important role in the vertebrate nervous system, where the absence of NF-κB activity during development can result in learning and memory deficits, whereas chronic NF-κB activation is associated with persistent neuroinflammation. We examined the functional role of RNF11 with respect to canonical NF-κB signaling in neurons to gain understanding of the tight association of inflammatory pathways, including NF-κB, with the pathogenesis of neurodegenerative diseases. Methods and results Luciferase assays were employed to assess NF-κB activity under targeted short hairpin RNA (shRNA knockdown of RNF11 in human neuroblastoma cells and murine primary neurons, which suggested that RNF11 acts as a negative regulator of canonical neuronal NF-κB signaling. These results were further supported by analyses of p65 translocation to the nucleus following depletion of RNF11. Coimmunoprecipitation experiments indicated that RNF11 associates with members of the A20 ubiquitin-editing protein complex in neurons. Site-directed mutagenesis of the myristoylation domain, which is necessary for endosomal targeting of RNF11, altered the impact of RNF11 on NF-κB signaling and abrogated RNF11’s association with the A20 ubiquitin-editing protein complex. A partial effect on canonical NF-κB signaling and an association with the A20 ubiquitin-editing protein complex was observed with mutagenesis of the PPxY motif, a proline-rich region involved in Nedd4-like protein interactions. Last, shRNA-mediated reduction of RNF11 in neurons and neuronal cell lines elevated levels of monocyte chemoattractant protein 1 and

  3. Development of Small Molecules Targeting the Wnt Signaling Pathway in Cancer Stem Cells for the Treatment of Colorectal Cancer.

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    Song, Lele; Li, Yuemin; He, Baoming; Gong, Yuan

    2015-09-01

    Colorectal cancer (CRC) was ranked third in morbidity and mortality in the United States in 2013. Although substantial progress has been made in surgical techniques and postoperative chemotherapy in recent years, the prognosis for colon cancer is still not satisfactory, mainly because of cancer recurrence and metastasis. The latest studies have shown that cancer stem cells (CSCs) play important roles in cancer recurrence and metastasis. Drugs that target CSCs might therefore have great therapeutic potential in prevention of cancer recurrence and metastasis. The wingless-int (Wnt) signaling pathway in CSCs has been suggested to play crucial roles in colorectal carcinogenesis, and has become a popular target for anti-CRC therapy. Dysregulation of the Wnt signaling pathway, mostly by inactivating mutations of the adenomatous polyposis coli tumor suppressor or oncogenic mutations of β-catenin, has been implicated as a key factor in colorectal tumorigenesis. Abnormal increases of β-catenin levels represents a common pathway in Wnt signaling activation and is also observed in other human malignancies. These findings highlight the importance of developing small-molecule drugs that target the Wnt pathway. Herein we provide an overview on the current development of small molecules that target the Wnt pathway in colorectal CSCs and discuss future research directions.

  4. Wnt-signaling and planar cell polarity genes regulate axon guidance along the anteroposterior axis in C. elegans.

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    Ackley, Brian D

    2014-08-01

    During the development of the nervous system, neurons encounter signals that inform their outgrowth and polarization. Understanding how these signals combinatorially function to pattern the nervous system is of considerable interest to developmental neurobiologists. The Wnt ligands and their receptors have been well characterized in polarizing cells during asymmetric cell division. The planar cell polarity (PCP) pathway is also critical for cell polarization in the plane of an epithelium. The core set of PCP genes include members of the conserved Wnt-signaling pathway, such as Frizzled and Disheveled, but also the cadherin-domain protein Flamingo. In Drosophila, the Fat and Dachsous cadherins also function in PCP, but in parallel to the core PCP components. C. elegans also have two Fat-like and one Dachsous-like cadherins, at least one of which, cdh-4, contributes to neural development. In C. elegans Wnt ligands and the conserved PCP genes have been shown to regulate a number of different events, including embryonic cell polarity, vulval morphogenesis, and cell migration. As is also observed in vertebrates, the Wnt and PCP genes appear to function to primarily provide information about the anterior to posterior axis of development. Here, we review the recent work describing how mutations in the Wnt and core PCP genes affect axon guidance and synaptogenesis in C. elegans.

  5. miR-612 suppresses the stemness of liver cancer via Wnt/β-catenin signaling

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    Tang, Jun [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China); Tao, Zhong-Hua [Department of Medical Oncology, Shanghai Cancer Center, Fudan University, Shanghai 200032 (China); Wen, Duo; Wan, Jin-Liang; Liu, Dong-Li; Zhang, Shu; Cui, Jie-Feng; Sun, Hui-Chuan; Wang, Lu [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China); Zhou, Jian; Fan, Jia [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China); Institute of Biomedical Sciences of Fudan University, Shanghai 200032 (China); Wu, Wei-Zhong, E-mail: wu.weizhong@zs-hospital.sh.cn [Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032 (China)

    2014-04-25

    Highlights: • miR-612 suppresses tumorsphere and clone formation of HCC cells. • miR-612 reduces drug resistance of HCC cells. • miR-612 suppresses tumorigenesis of HCC in NOD/SCID mice. • miR-612 inhibits an invasive frontier of HCC xenografts. • miR-612 suppresses Wnt/β-catenin signaling. - Abstract: Previous research showed that microRNA-612 (miR-612) has inhibitory effects on cell proliferation, migration, invasion, and metastasis of hepatocellular carcinoma (HCC). AKT2 was confirmed to be a direct target of miR-612, through which the epithelial–mesenchymal transition (EMT) and metastasis of HCC were inhibited. Our present findings reveal that miR-612 is able to suppress the stemness of HCC by reducing the number and size of tumorspheres as well as clone formation in soft agar, and to relieve drug resistance to cisplatin and 5-fluorouracil. In addition, miR-612 hampered the capacity of tumorigenesis in NOD/SCID mice and redistributed the tumor invasive frontier of miR-612-modulating cells. Finally, our findings suggest that Wnt/β-catenin signaling is required in the regulation of EMT-associated stem cell-like traits by miR-612.

  6. Wnt/β-catenin signaling pathway is active in pancreatic development of rat embryo

    Institute of Scientific and Technical Information of China (English)

    Qi-Ming Wang; Ye Zhang; Kai-Ming Yang; Hong-Ying Zhou; Hui-Jun Yang

    2006-01-01

    AIM: To elucidate the role of Wnt/β-catenin signaling pathway in pancreatic development of rat embryo.METHODS: The mRNAs of β-catenin, APC, cyclin D1 genes were amplified by means of semiquantitative reverse transcription polymerase chain reaction (RTPCR) from embryonic pancreas in different periods and normal pancreas of rat, respectively. Protein expression of these genes in embryonic pancreas of E14.5-E18.5was examined by immunohistochemical method.RESULTS: In embryonic pancreas of E14.5, the transcript amplification of β-catenin and cyclinD1 genes was detected. In embryonic pancreas of E18.5, the transcription levels of β-catenin and cyclinD1 genes became much higher than in other periods. But in adult rat pancreas the transcription of cyclinD1 gene could not be observed. Only until E18.5, the transcript amplification of mRNA of APC gene could be detected.Surprisingly, the transcription level of APC gene became much higher in adult rat pancreas than in embryonic pancreas. By means of immunohistochemical staining,identical results were obtained to the above by RP-PCR,except for β-catenin protein in adult rat pancreas.CONCLUSION: Active Wnt/β-catenin signaling occursin rat embryonic pancreas and is probably important for pancreatic development and organ formation.

  7. Wnt/β-Catenin Signaling Triggers Neuron Reprogramming and Regeneration in the Mouse Retina

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    Daniela Sanges

    2013-07-01

    Full Text Available Cell-fusion-mediated somatic-cell reprogramming can be induced in culture; however, whether this process occurs in mammalian tissues remains enigmatic. Here, we show that upon activation of Wnt/β-catenin signaling, mouse retinal neurons can be transiently reprogrammed in vivo back to a precursor stage. This occurs after their spontaneous fusion with transplanted hematopoietic stem and progenitor cells (HSPCs. Moreover, we demonstrate that retinal damage is essential for cell-hybrid formation in vivo. Newly formed hybrids can proliferate, commit to differentiation toward a neuroectodermal lineage, and finally develop into terminally differentiated neurons. This results in partial regeneration of the damaged retinal tissue, with functional rescue. Following retinal damage and induction of Wnt/β-catenin signaling, cell-fusion-mediated reprogramming also occurs after endogenous recruitment of bone-marrow-derived cells in the eyes. Our data demonstrate that in vivo reprogramming of terminally differentiated retinal neurons after their fusion with HSPCs is a potential mechanism for tissue regeneration.

  8. Trophoblast glycoprotein promotes pancreatic ductal adenocarcinoma cell metastasis through Wnt/planar cell polarity signaling.

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