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Sample records for generates wnt protein

  1. Stearoyl CoA Desaturase Is Required to Produce Active, Lipid-Modified Wnt Proteins

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    Jessica Rios-Esteves

    2013-09-01

    Full Text Available Wnt proteins contain palmitoleic acid, an unusual lipid modification. Production of an active Wnt signal requires the acyltransferase Porcupine and depends on the attachment of palmitoleic acid to Wnt. The source of this monounsaturated fatty acid has not been identified, and it is not known how Porcupine recognizes its substrate and whether desaturation occurs before or after fatty acid transfer to Wnt. Here, we show that stearoyl desaturase (SCD generates a monounsaturated fatty acid substrate that is then transferred by Porcupine to Wnt. Treatment of cells with SCD inhibitors blocked incorporation of palmitate analogs into Wnt3a and Wnt5a and reduced Wnt secretion as well as autocrine and paracrine Wnt signaling. The SCD inhibitor effects were rescued by exogenous addition of monounsaturated fatty acids. We propose that SCD is a key molecular player responsible for Wnt biogenesis and processing and that SCD inhibition provides an alternative mechanism for blocking Wnt pathway activation.

  2. Dissecting the Wnt secretion pathway: key questions on the modification and intracellular trafficking of Wnt proteins

    NARCIS (Netherlands)

    Harterink, M.; Korswagen, H.C.

    2012-01-01

    The Wnt family of signalling proteins has essential functions in development and adult tissue homoeostasis throughout the animal kingdom. Although signalling cascades triggered by Wnt proteins have been extensively studied, much remains to be learned about how Wnts are produced and secreted. Over

  3. Secretion and extracellular space travel of Wnt proteins.

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    Gross, Julia Christina; Boutros, Michael

    2013-08-01

    Wnt signaling pathways control many processes during development, stem cell maintenance and homeostasis, and their aberrant regulation has been linked to diseases in man including diabetes, neurodegeneration and cancer. Wnts are hydrophobic proteins, however, quite paradoxically, they can travel over distances to induce cell-type specific responses. While there has been an initial focus on elucidating the intracellular signaling cascade, discoveries in the past few years have shed light on a highly complex, and regulated secretory process that guides Wnt proteins through the exocytic pathway. Wnt proteins are at least in portion packaged onto extracellular carriers such as exosomes. Similar to dysregulation of components in the Wnt receiving cell, failure to regulate Wnt secretion has been linked to cancer. Here, we review recent discoveries on factors and processes implicated in Wnt secretion. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Wnt/Yes-Associated Protein Interactions During Neural Tissue Patterning of Human Induced Pluripotent Stem Cells.

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    Bejoy, Julie; Song, Liqing; Zhou, Yi; Li, Yan

    2018-04-01

    Human induced pluripotent stem cells (hiPSCs) have special ability to self-assemble into neural spheroids or mini-brain-like structures. During the self-assembly process, Wnt signaling plays an important role in regional patterning and establishing positional identity of hiPSC-derived neural progenitors. Recently, the role of Wnt signaling in regulating Yes-associated protein (YAP) expression (nuclear or cytoplasmic), the pivotal regulator during organ growth and tissue generation, has attracted increasing interests. However, the interactions between Wnt and YAP expression for neural lineage commitment of hiPSCs remain poorly explored. The objective of this study is to investigate the effects of Wnt signaling and YAP expression on the cellular population in three-dimensional (3D) neural spheroids derived from hiPSCs. In this study, Wnt signaling was activated using CHIR99021 for 3D neural spheroids derived from human iPSK3 cells through embryoid body formation. Our results indicate that Wnt activation induces nuclear localization of YAP and upregulates the expression of HOXB4, the marker for hindbrain/spinal cord. By contrast, the cells exhibit more rostral forebrain neural identity (expression of TBR1) without Wnt activation. Cytochalasin D was then used to induce cytoplasmic YAP and the results showed the decreased HOXB4 expression. In addition, the incorporation of microparticles in the neural spheroids was investigated for the perturbation of neural patterning. This study may indicate the bidirectional interactions of Wnt signaling and YAP expression during neural tissue patterning, which have the significance in neurological disease modeling, drug screening, and neural tissue regeneration.

  5. Lipid-mediated Wnt protein stabilization enables serum-free culture of human organ stem cells

    NARCIS (Netherlands)

    Tüysüz, Nesrin; van Bloois, Louis|info:eu-repo/dai/nl/304839183; van den Brink, Stieneke; Begthel, Harry; Verstegen, Monique M A; Cruz, Luis J; Hui, Lijian; van der Laan, Luc J W; de Jonge, Jeroen; Vries, Robert; Braakman, Eric; Mastrobattista, Enrico|info:eu-repo/dai/nl/228061105; Cornelissen, Jan J; Clevers, Hans|info:eu-repo/dai/nl/07164282X; Ten Berge, Derk

    2017-01-01

    Wnt signalling proteins are essential for culture of human organ stem cells in organoids, but most Wnt protein formulations are poorly active in serum-free media. Here we show that purified Wnt3a protein is ineffective because it rapidly loses activity in culture media due to its hydrophobic nature,

  6. Cytokinesis proteins Tum and Pav have a nuclear role in Wnt regulation.

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    Jones, Whitney M; Chao, Anna T; Zavortink, Michael; Saint, Robert; Bejsovec, Amy

    2010-07-01

    Wg/Wnt signals specify cell fates in both invertebrate and vertebrate embryos and maintain stem-cell populations in many adult tissues. Deregulation of the Wnt pathway can transform cells to a proliferative fate, leading to cancer. We have discovered that two Drosophila proteins that are crucial for cytokinesis have a second, largely independent, role in restricting activity of the Wnt pathway. The fly homolog of RacGAP1, Tumbleweed (Tum)/RacGAP50C, and its binding partner, the kinesin-like protein Pavarotti (Pav), negatively regulate Wnt activity in fly embryos and in cultured mammalian cells. Unlike many known regulators of the Wnt pathway, these molecules do not affect stabilization of Arm/beta-catenin (betacat), the principal effector molecule in Wnt signal transduction. Rather, they appear to act downstream of betacat stabilization to control target-gene transcription. Both Tum and Pav accumulate in the nuclei of interphase cells, a location that is spatially distinct from their cleavage-furrow localization during cytokinesis. We show that this nuclear localization is essential for their role in Wnt regulation. Thus, we have identified two modulators of the Wnt pathway that have shared functions in cell division, which hints at a possible link between cytokinesis and Wnt activity during tumorigenesis.

  7. A novel set of Wnt-Frizzled fusion proteins identifies receptor components that activate beta -catenin-dependent signaling.

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    Holmen, Sheri L; Salic, Adrian; Zylstra, Cassandra R; Kirschner, Marc W; Williams, Bart O

    2002-09-20

    Wnt proteins initiate the canonical (beta-catenin-regulated) signaling cascade by binding to seven-transmembrane spanning receptors of the Frizzled (Fz) family together with the coreceptors LRP5 and -6, members of the low density lipoprotein receptor-related protein family (LRP). Several reports have shown physical and functional associations between various Wnt, LRP, and Frizzled molecules; however, the underlying mechanisms for selectivity remain poorly understood. We present data on a novel set of Wnt-Fz fusion constructs that are useful for elucidating mechanisms of Wnt signal transduction specificity in both Xenopus embryos and 293T cells. In 293T cells, coexpression of several Wnt-Fz fusion proteins with LRP6, but not LRP5, significantly activated a Wnt-responsive promoter, Optimized TOPFlash. Interestingly, Wnt proteins from both the Wnt1 and Wnt5A classes, when fused to the same Frizzled, can synergize with LRP6 to activate signaling and induce secondary axes in Xenopus embryos. However, when several Wnt-Fz constructs containing different Frizzled molecules were tested, it was found that all Frizzled molecules are not equivalent in their ability to activate the canonical Wnt pathway in this context. The data suggest that the distinction between the two Wnt classes lies not in intrinsic differences in the molecules but via the Frizzled molecules with which they interact.

  8. Mitotic Spindle Asymmetry: A Wnt/PCP-Regulated Mechanism Generating Asymmetrical Division in Cortical Precursors

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    Delphine Delaunay

    2014-01-01

    Full Text Available The regulation of asymmetric cell division (ACD during corticogenesis is incompletely understood. We document that spindle-size asymmetry (SSA between the two poles occurs during corticogenesis and parallels ACD. SSA appears at metaphase and is maintained throughout division, and we show it is necessary for proper neurogenesis. Imaging of spindle behavior and division outcome reveals that neurons preferentially arise from the larger-spindle pole. Mechanistically, SSA magnitude is controlled by Wnt7a and Vangl2, both members of the Wnt/planar cell polarity (PCP-signaling pathway, and relayed to the cell cortex by P-ERM proteins. In vivo, Vangl2 and P-ERM downregulation promotes early cell-cycle exit and prevents the proper generation of late-born neurons. Thus, SSA is a core component of ACD that is conserved in invertebrates and vertebrates and plays a key role in the tight spatiotemporal control of self-renewal and differentiation during mammalian corticogenesis.

  9. 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

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

    International Nuclear Information System (INIS)

    Kawamoto, E.M.; Gleichmann, M.; Yshii, L.M.; Sá Lima, L. de; Mattson, M.P.; Scavone, C.

    2011-01-01

    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 25-35 ; 50 µM). Cells (1 × 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

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

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    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.

  12. 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.

  13. 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.

  14. Inflammation Intensity-dependent Expression of Osteoinductive Wnt Proteins is Critical for Ectopic New Bone Formation in Ankylosing Spondylitis.

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    Li, Xiang; Wang, Jianru; Zhan, Zhongping; Li, Sibei; Zheng, Zhaomin; Wang, Taiping; Zhang, Kuibo; Pan, Hehai; Li, Zemin; Zhang, Nu; Liu, Hui

    2018-02-26

    To investigate the molecular mechanism underlying the inflammation- related ectopic new bone formation in ankylosing spondylitis (AS). Spinal tissues and sera were collected from patients or normal volunteers to detect the expression of Wnt proteins. An in vitro cell culture system mimicking the local inflammatory microenvironment of bone-forming sites was established to study the relationship between inflammation and Wnt expression, the regulatory mechanism of inflammation-induced Wnt expression and the role of Wnt signaling in new bone formation. A modified collagen-induced arthritis (mCIA) and a proteoglycan -induced spondylitis (PGIS) animal model were used to confirm the key findings in vivo. The levels of osteoinductive Wnt proteins were obviously increased in the sera and spinal ligament tissues of patients with AS. Only constitutive low-intensity TNF-α stimulation, but not short-term or high-intensity TNF-α stimulation, induced persistent expression of osteoinductive Wnt proteins and subsequent bone formation through NF-κB (p65) and JNK/AP-1 (c-Jun) signaling pathways. Furthermore, inhibition of either Wnt/β-catenin or Wnt/PKCδ pathway significantly suppressed new bone formation. The increased expression of Wnt proteins was confirmed in both mCIA and PGIS models. A kyphotic and ankylosing phenotype of the spine was observed during long-term observation in mCIA model. Inhibition of either Wnt/β-catenin or Wnt/PKCδ signaling pathway significantly reduced the incidence and severity of this phenotype. Inflammation intensity-dependent expression of osteoinductive Wnt proteins is a key link between inflammation and ectopic new bone formation in AS. Activation of both canonical Wnt/β-catenin and noncanonical Wnt/PKCδ pathways is required for inflammation-induced new bone formation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  15. Secreted Frizzled-related protein-2 (sFRP2) augments canonical Wnt3a-induced signaling

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    Marschall, Zofia von; Fisher, Larry W.

    2010-01-01

    Research highlights: → sFRP2 enhances the Wnt3a-induced β-catenin stabilization and its nuclear translocation. → sFRP2 enhances LRP6 phosphorylation and Wnt3a/β-catenin transcriptional reporter activity. → Dickkopf-1 (DKK1) fully antagonizes both Wnt3a/sFRP2-induced LRP6 phosphorylation and transcriptional activity. → sFRP2 enhances expression of genes known to be regulated by Wnt3a signaling. -- Abstract: Secreted Frizzled-related proteins (sFRP) are involved in embryonic development as well as pathological conditions including bone and myocardial disorders and cancer. Because of their sequence homology with the Wnt-binding domain of Frizzled, they have generally been considered antagonists of canonical Wnt signaling. However, additional activities of various sFRPs including both synergism and mimicry of Wnt signaling as well as functions other than modulation of Wnt signaling have been reported. Using human embryonic kidney cells (HEK293A), we found that sFRP2 enhanced Wnt3a-dependent phosphorylation of LRP6 as well as both cytosolic β-catenin levels and its nuclear translocation. While addition of recombinant sFRP2 had no activity by itself, Top/Fop luciferase reporter assays showed a dose-dependent increase of Wnt3a-mediated transcriptional activity. sFRP2 enhancement of Wnt3a signaling was abolished by treatment with the Wnt antagonist, Dickkopf-1 (DKK1). Wnt-signaling pathway qPCR arrays showed that sFRP2 enhanced the Wnt3a-mediated transcriptional up-regulation of several genes regulated by Wnt3a including its antagonists, DKK1, and Naked cuticle-1 homolog (NKD1). These results support sFRP2's role as an enhancer of Wnt/β-catenin signaling, a result with biological impact for both normal development and diverse pathologies such as tumorigenesis.

  16. Secreted Frizzled-related protein-2 (sFRP2) augments canonical Wnt3a-induced signaling

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    Marschall, Zofia von [Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, MD (United States); Fisher, Larry W., E-mail: lfisher@dir.nidcr.nih.gov [Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, MD (United States)

    2010-09-24

    Research highlights: {yields} sFRP2 enhances the Wnt3a-induced {beta}-catenin stabilization and its nuclear translocation. {yields} sFRP2 enhances LRP6 phosphorylation and Wnt3a/{beta}-catenin transcriptional reporter activity. {yields} Dickkopf-1 (DKK1) fully antagonizes both Wnt3a/sFRP2-induced LRP6 phosphorylation and transcriptional activity. {yields} sFRP2 enhances expression of genes known to be regulated by Wnt3a signaling. -- Abstract: Secreted Frizzled-related proteins (sFRP) are involved in embryonic development as well as pathological conditions including bone and myocardial disorders and cancer. Because of their sequence homology with the Wnt-binding domain of Frizzled, they have generally been considered antagonists of canonical Wnt signaling. However, additional activities of various sFRPs including both synergism and mimicry of Wnt signaling as well as functions other than modulation of Wnt signaling have been reported. Using human embryonic kidney cells (HEK293A), we found that sFRP2 enhanced Wnt3a-dependent phosphorylation of LRP6 as well as both cytosolic {beta}-catenin levels and its nuclear translocation. While addition of recombinant sFRP2 had no activity by itself, Top/Fop luciferase reporter assays showed a dose-dependent increase of Wnt3a-mediated transcriptional activity. sFRP2 enhancement of Wnt3a signaling was abolished by treatment with the Wnt antagonist, Dickkopf-1 (DKK1). Wnt-signaling pathway qPCR arrays showed that sFRP2 enhanced the Wnt3a-mediated transcriptional up-regulation of several genes regulated by Wnt3a including its antagonists, DKK1, and Naked cuticle-1 homolog (NKD1). These results support sFRP2's role as an enhancer of Wnt/{beta}-catenin signaling, a result with biological impact for both normal development and diverse pathologies such as tumorigenesis.

  17. Identification of a WNT5A-Responsive Degradation Domain in the Kinesin Superfamily Protein KIF26B

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    Edith P. Karuna

    2018-04-01

    Full Text Available Noncanonical WNT pathways function independently of the β-catenin transcriptional co-activator to regulate diverse morphogenetic and pathogenic processes. Recent studies showed that noncanonical WNTs, such as WNT5A, can signal the degradation of several downstream effectors, thereby modulating these effectors’ cellular activities. The protein domain(s that mediates the WNT5A-dependent degradation response, however, has not been identified. By coupling protein mutagenesis experiments with a flow cytometry-based degradation reporter assay, we have defined a protein domain in the kinesin superfamily protein KIF26B that is essential for WNT5A-dependent degradation. We found that a human disease-causing KIF26B mutation located at a conserved amino acid within this domain compromises the ability of WNT5A to induce KIF26B degradation. Using pharmacological perturbation, we further uncovered a role of glycogen synthase kinase 3 (GSK3 in WNT5A regulation of KIF26B degradation. Lastly, based on the identification of the WNT5A-responsive domain, we developed a new reporter system that allows for efficient profiling of WNT5A-KIF26B signaling activity in both somatic and stem cells. In conclusion, our study identifies a new protein domain that mediates WNT5A-dependent degradation of KIF26B and provides a new tool for functional characterization of noncanonical WNT5A signaling in cells.

  18. Protein Phosphatase 2A in the Regulation of Wnt Signaling, Stem Cells, and Cancer.

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    Thompson, Joshua J; Williams, Christopher S

    2018-02-26

    Protein phosphorylation is a ubiquitous cellular process that allows for the nuanced and reversible regulation of protein activity. Protein phosphatase 2A (PP2A) is a heterotrimeric serine-threonine phosphatase-composed of a structural, regulatory, and catalytic subunit-that controls a variety of cellular events via protein dephosphorylation. While much is known about PP2A and its basic biochemistry, the diversity of its components-especially the multitude of regulatory subunits-has impeded the determination of PP2A function. As a consequence of this complexity, PP2A has been shown to both positively and negatively regulate signaling networks such as the Wnt pathway. Wnt signaling modulates major developmental processes, and is a dominant mediator of stem cell self-renewal, cell fate, and cancer stem cells. Because PP2A affects Wnt signaling both positively and negatively and at multiple levels, further understanding of this complex dynamic may ultimately provide insight into stem cell biology and how to better treat cancers that result from alterations in Wnt signaling. This review will summarize literature that implicates PP2A as a tumor suppressor, explore PP2A mutations identified in human malignancy, and focus on PP2A in the regulation of Wnt signaling and stem cells so as to better understand how aberrancy in this pathway can contribute to tumorigenesis.

  19. Protein Phosphatase 2A in the Regulation of Wnt Signaling, Stem Cells, and Cancer

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    Joshua J. Thompson

    2018-02-01

    Full Text Available Protein phosphorylation is a ubiquitous cellular process that allows for the nuanced and reversible regulation of protein activity. Protein phosphatase 2A (PP2A is a heterotrimeric serine-threonine phosphatase—composed of a structural, regulatory, and catalytic subunit—that controls a variety of cellular events via protein dephosphorylation. While much is known about PP2A and its basic biochemistry, the diversity of its components—especially the multitude of regulatory subunits—has impeded the determination of PP2A function. As a consequence of this complexity, PP2A has been shown to both positively and negatively regulate signaling networks such as the Wnt pathway. Wnt signaling modulates major developmental processes, and is a dominant mediator of stem cell self-renewal, cell fate, and cancer stem cells. Because PP2A affects Wnt signaling both positively and negatively and at multiple levels, further understanding of this complex dynamic may ultimately provide insight into stem cell biology and how to better treat cancers that result from alterations in Wnt signaling. This review will summarize literature that implicates PP2A as a tumor suppressor, explore PP2A mutations identified in human malignancy, and focus on PP2A in the regulation of Wnt signaling and stem cells so as to better understand how aberrancy in this pathway can contribute to tumorigenesis.

  20. Effects of hepatitis C virus core protein and nonstructural protein 4B on the Wnt/β-catenin pathway.

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    Jiang, Xiao-Hua; Xie, Yu-Tao; Cai, Ya-Ping; Ren, Jing; Ma, Tao

    2017-05-25

    Hepatitis C virus (HCV) core protein and nonstructural protein 4B (NS4B) are potentially oncogenic. Aberrant activation of the Wnt/β-catenin signaling pathway is closely associated with hepatocarcinogenesis. We investigated the effects of HCV type 1b core protein and NS4B on Wnt/β-catenin signaling in various liver cells, and explored the molecular mechanism underlying HCV-related hepatocarcinogenesis. Compared with the empty vector control, HCV core protein and NS4B demonstrated the following characteristics in the Huh7 cells: significantly enhanced β-catenin/Tcf-dependent transcriptional activity (F = 40.87, P  0.05), but they did significantly enhance Wnt3a-induced β-catenin/Tcf-dependent transcriptional activity (F = 64.25, P core protein than with NS4B (P core protein and NS4B directly activate the Wnt/β-catenin signaling pathway in Huh7 cells and LO2 cells induced by Wnt3a. These data suggest that HCV core protein and NS4B contribute to HCV-associated hepatocellular carcinogenesis.

  1. 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.

  2. Dickkopf-related protein 1 inhibits the WNT signaling pathway and improves pig oocyte maturation.

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    Lee D Spate

    Full Text Available The ability to mature oocytes in vitro provides a tool for creating embryos by parthenogenesis, fertilization, and cloning. Unfortunately the quality of oocytes matured in vitro falls behind that of in vivo matured oocytes. To address this difference, transcriptional profiling by deep sequencing was conducted on pig oocytes that were either matured in vitro or in vivo. Alignment of over 18 million reads identified 1,316 transcripts that were differentially represented. One pathway that was overrepresented in the oocytes matured in vitro was for Wingless-type MMTV integration site (WNT signaling. In an attempt to inhibit the WNT pathway, Dickkopf-related protein 1 was added to the in vitro maturation medium. Addition of Dickkopf-related protein 1 improved the percentage of oocytes that matured to the metaphase II stage, increased the number of nuclei in the resulting blastocyst stage embryos, and reduced the amount of disheveled segment polarity protein 1 protein in oocytes. It is concluded that transcriptional profiling is a powerful method for detecting differences between in vitro and in vivo matured oocytes, and that the WNT signaling pathway is important for proper oocyte maturation.

  3. CREB-binding protein, p300, butyrate, and Wnt signaling in colorectal cancer.

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    Bordonaro, Michael; Lazarova, Darina L

    2015-07-21

    This paper reviews the distinctive roles played by the transcriptional coactivators CREB-binding protein (CBP) and p300 in Wnt/β-catenin signaling and cell physiology in colorectal cancer (CRC). Specifically, we focus on the effects of CBP- and p300-mediated Wnt activity on (1) neoplastic progression; (2) the activities of butyrate, a breakdown product of dietary fiber, on cell signaling and colonic cell physiology; (3) the development of resistance to histone deacetylase inhibitors (HDACis), including butyrate and synthetic HDACis, in colonic cells; and (4) the physiology and number of cancer stem cells. Mutations of the Wnt/β-catenin signaling pathway initiate the majority of CRC cases, and we have shown that hyperactivation of this pathway by butyrate and other HDACis promotes CRC cell apoptosis. This activity by butyrate may in part explain the preventive action of fiber against CRC. However, individuals with a high-fiber diet may still develop neoplasia; therefore, resistance to the chemopreventive action of butyrate likely contributes to CRC. CBP or p300 may modify the ability of butyrate to influence colonic cell physiology since the two transcriptional coactivators affect Wnt signaling, and likely, its hyperactivation by butyrate. Also, CBP and p300 likely affect colonic tumorigenesis, as well as stem cell pluripotency. Improvement of CRC prevention and therapy requires a better understanding of the alterations in Wnt signaling and gene expression that underlie neoplastic progression, stem cell fate, and the development of resistance to butyrate and clinically relevant HDACis. Detailed knowledge of how CBP- and p300 modulate colonic cell physiology may lead to new approaches for anti-CRC prevention and therapeutics, particularly with respect to combinatorial therapy of CBP/p300 inhibitors with HDACis.

  4. Parathyroid hormone-related protein activates Wnt signaling to specify the embryonic mammary mesenchyme.

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    Hiremath, Minoti; Dann, Pamela; Fischer, Jennifer; Butterworth, Daniela; Boras-Granic, Kata; Hens, Julie; Van Houten, Joshua; Shi, Wei; Wysolmerski, John

    2012-11-01

    Parathyroid hormone-related protein (PTHrP) regulates cell fate and specifies the mammary mesenchyme during embryonic development. Loss of PTHrP or its receptor (Pthr1) abolishes the expression of mammary mesenchyme markers and allows mammary bud cells to revert to an epidermal fate. By contrast, overexpression of PTHrP in basal keratinocytes induces inappropriate differentiation of the ventral epidermis into nipple-like skin and is accompanied by ectopic expression of Lef1, β-catenin and other markers of the mammary mesenchyme. In this study, we document that PTHrP modulates Wnt/β-catenin signaling in the mammary mesenchyme using a Wnt signaling reporter, TOPGAL-C. Reporter expression is completely abolished by loss of PTHrP signaling and ectopic reporter activity is induced by overexpression of PTHrP. We also demonstrate that loss of Lef1, a key component of the Wnt pathway, attenuates the PTHrP-induced abnormal differentiation of the ventral skin. To characterize further the contribution of canonical Wnt signaling to embryonic mammary development, we deleted β-catenin specifically in the mammary mesenchyme. Loss of mesenchymal β-catenin abolished expression of the TOPGAL-C reporter and resulted in mammary buds with reduced expression of mammary mesenchyme markers and impaired sexual dimorphism. It also prevented the ectopic, ventral expression of mammary mesenchyme markers caused by overexpression of PTHrP in basal keratinocytes. Therefore, we conclude that a mesenchymal, canonical Wnt pathway mediates the PTHrP-dependent specification of the mammary mesenchyme.

  5. Differential Expression and Roles of Secreted Frizzled-Related Protein 5 and the Wingless Homolog Wnt5a in Periodontitis.

    Science.gov (United States)

    Maekawa, T; Kulwattanaporn, P; Hosur, K; Domon, H; Oda, M; Terao, Y; Maeda, T; Hajishengallis, G

    2017-05-01

    The Wingless/integrase-1 (Wnt) family of protein ligands and their functional antagonists, secreted frizzled-related proteins (sFRPs), regulate various biological processes ranging from embryonic development to immunity and inflammation. Wnt5a and sFRP5 comprise a typical ligand/antagonist pair, and the former molecule was recently detected at the messenger RNA (mRNA) level in human periodontitis. The main objective of this study was to investigate the interrelationship of expression of Wnt5a and sFRP5 in human periodontitis (as compared to health) and to determine their roles in inflammation and bone loss in an animal model. We detected both Wnt5a and sFRP5 mRNA in human gingiva, with Wnt5a dominating in diseased and sFRP5 in healthy tissue. Wnt5a and sFRP5 protein colocalized in the gingival epithelium, suggesting epithelial cell expression, which was confirmed in cultured human gingival epithelial cells (HGECs). The HGEC expression of Wnt5a and sFRP5 was differentially regulated by a proinflammatory stimulus (lipopolysaccharide [LPS] from Porphyromonas gingivalis) in a manner consistent with the clinical observations (i.e., LPS upregulated Wnt5a and downregulated sFRP5). In HGECs, exogenously added Wnt5a enhanced whereas sFRP5 inhibited LPS-induced inflammation, as monitored by interleukin 8 production. Consistent with this, local treatment with sFRP5 in mice subjected to ligature-induced periodontitis inhibited inflammation and bone loss, correlating with decreased numbers of osteoclasts in bone tissue sections. As in humans, mouse periodontitis was associated with high expression of Wnt5a and low expression of sFRP5, although this profile was reversed after treatment with sFRP5. In conclusion, we demonstrated a novel reciprocal relationship between sFRP5 and Wnt5a expression in periodontal health and disease, paving the way to clinical investigation of the possibility of using the Wnt5a/sFRP5 ratio as a periodontitis biomarker. Moreover, we showed that sFRP5

  6. Wnt/β-Catenin Pathway Is Regulated by PITX2 Homeodomain Protein and Thus Contributes to the Proliferation of Human Ovarian Adenocarcinoma Cell, SKOV-3*

    Science.gov (United States)

    Basu, Moitri; Roy, Sib Sankar

    2013-01-01

    Pituitary homeobox-2 (PITX2) plays a substantial role in the development of pituitary, heart, and brain. Although the role of PITX2 isoforms in embryonic development has been extensively studied, its possible involvement in regulating the Wnt signaling pathway has not been reported. Because the Wnt pathway is strongly involved in ovarian development and cancer, we focused on the possible association between PITX2 and Wnt pathway in ovarian carcinoma cells. Remarkably, we found that PITX2 interacts and regulates WNT2/5A/9A/6/2B genes of the canonical, noncanonical, or other pathways in the human ovarian cancer cell SKOV-3. Chromatin immunoprecipitation and promoter-reporter assays further indicated the significant association of PITX2 with WNT2 and WNT5A promoters. Detailed study further reveals that the PITX2 isoform specifically activates the canonical Wnt signaling pathway either directly or through Wnt ligands. Thus, the activated Wnt pathway subsequently enhances cell proliferation. Moreover, we found the activation of Wnt pathway reduces the expression of different FZD receptors that limit further Wnt activation, demonstrating the existence of an auto-regulatory feedback loop. In contrast, PITX2 could not activate the noncanonical pathway as the Wnt5A-specific ROR2 receptor does not express in SKOV-3 cells. Collectively, our findings demonstrated that, despite being a target of the canonical Wnt signaling pathway, PITX2 itself induces the same, thus leading to the activation of the cell cycle regulating genes as well as the proliferation of SKOV-3 cells. Collectively, we highlighted that the PITX2 and Wnt pathway exerts a positive feedback regulation, whereas frizzled receptors generate a negative feedback in this pathway. Our findings will help to understand the molecular mechanism of proliferation in ovarian cancer cells. PMID:23250740

  7. Wnt/β-catenin pathway is regulated by PITX2 homeodomain protein and thus contributes to the proliferation of human ovarian adenocarcinoma cell, SKOV-3.

    Science.gov (United States)

    Basu, Moitri; Roy, Sib Sankar

    2013-02-08

    Pituitary homeobox-2 (PITX2) plays a substantial role in the development of pituitary, heart, and brain. Although the role of PITX2 isoforms in embryonic development has been extensively studied, its possible involvement in regulating the Wnt signaling pathway has not been reported. Because the Wnt pathway is strongly involved in ovarian development and cancer, we focused on the possible association between PITX2 and Wnt pathway in ovarian carcinoma cells. Remarkably, we found that PITX2 interacts and regulates WNT2/5A/9A/6/2B genes of the canonical, noncanonical, or other pathways in the human ovarian cancer cell SKOV-3. Chromatin immunoprecipitation and promoter-reporter assays further indicated the significant association of PITX2 with WNT2 and WNT5A promoters. Detailed study further reveals that the PITX2 isoform specifically activates the canonical Wnt signaling pathway either directly or through Wnt ligands. Thus, the activated Wnt pathway subsequently enhances cell proliferation. Moreover, we found the activation of Wnt pathway reduces the expression of different FZD receptors that limit further Wnt activation, demonstrating the existence of an auto-regulatory feedback loop. In contrast, PITX2 could not activate the noncanonical pathway as the Wnt5A-specific ROR2 receptor does not express in SKOV-3 cells. Collectively, our findings demonstrated that, despite being a target of the canonical Wnt signaling pathway, PITX2 itself induces the same, thus leading to the activation of the cell cycle regulating genes as well as the proliferation of SKOV-3 cells. Collectively, we highlighted that the PITX2 and Wnt pathway exerts a positive feedback regulation, whereas frizzled receptors generate a negative feedback in this pathway. Our findings will help to understand the molecular mechanism of proliferation in ovarian cancer cells.

  8. Mechanisms of Wnt signaling and control.

    Science.gov (United States)

    Grainger, Stephanie; Willert, Karl

    2018-03-30

    The Wnt signaling pathway is a highly conserved system that regulates complex biological processes across all metazoan species. At the cellular level, secreted Wnt proteins serve to break symmetry and provide cells with positional information that is critical to the patterning of the entire body plan. At the organismal level, Wnt signals are employed to orchestrate fundamental developmental processes, including the specification of the anterior-posterior body axis, induction of the primitive streak and ensuing gastrulation movements, and the generation of cell and tissue diversity. Wnt functions extend into adulthood where they regulate stem cell behavior, tissue homeostasis, and damage repair. Disruption of Wnt signaling activity during embryonic development or in adults results in a spectrum of abnormalities and diseases, including cancer. The molecular mechanisms that underlie the myriad of Wnt-regulated biological effects have been the subject of intense research for over three decades. This review is intended to summarize our current understanding of how Wnt signals are generated and interpreted. This article is categorized under: Biological Mechanisms > Cell Signaling Developmental Biology > Stem Cell Biology and Regeneration. © 2018 Wiley Periodicals, Inc.

  9. Organized emergence of multiple-generations of teeth in snakes is dysregulated by activation of Wnt/beta-catenin signalling.

    Directory of Open Access Journals (Sweden)

    Marcia Gaete

    Full Text Available In contrast to mammals, most reptiles constantly regenerate their teeth. In the snake, the epithelial dental lamina ends in a successional lamina, which proliferates and elongates forming multiple tooth generations, all linked by a permanent dental lamina. To investigate the mechanisms used to control the initiation of new tooth germs in an ordered sequential pattern we utilized the polyphodont (multiple-generation corn snake (Pantherophis guttatus. We observed that the dental lamina expressed the transcription factor Sox2, a multipotent stem cell marker, whereas the successional lamina cells expressed the transcription factor Lef1, a Wnt/β-catenin pathway target gene. Activation of the Wnt/β-catenin pathway in culture increased the number of developing tooth germs, in comparison to control untreated cultures. These additional tooth germs budded off from ectopic positions along the dental lamina, rather than in an ordered sequence from the successional lamina. Wnt/β-catenin activation enhanced cell proliferation, particularly in normally non-odontogenic regions of the dental lamina, which widely expressed Lef1, restricting the Sox2 domain. This suggests an expansion of the successional lamina at the expense of the dental lamina. Activation of the Wnt/β-catenin pathway in cultured snake dental organs, therefore, led to changes in proliferation and to the molecular pattern of the dental lamina, resulting in loss of the organised emergence of tooth germs. These results suggest that epithelial compartments are critical for the arrangement of organs that develop in sequence, and highlight the role of Wnt/β-catenin signalling in such processes.

  10. Organized emergence of multiple-generations of teeth in snakes is dysregulated by activation of Wnt/beta-catenin signalling.

    Science.gov (United States)

    Gaete, Marcia; Tucker, Abigail S

    2013-01-01

    In contrast to mammals, most reptiles constantly regenerate their teeth. In the snake, the epithelial dental lamina ends in a successional lamina, which proliferates and elongates forming multiple tooth generations, all linked by a permanent dental lamina. To investigate the mechanisms used to control the initiation of new tooth germs in an ordered sequential pattern we utilized the polyphodont (multiple-generation) corn snake (Pantherophis guttatus). We observed that the dental lamina expressed the transcription factor Sox2, a multipotent stem cell marker, whereas the successional lamina cells expressed the transcription factor Lef1, a Wnt/β-catenin pathway target gene. Activation of the Wnt/β-catenin pathway in culture increased the number of developing tooth germs, in comparison to control untreated cultures. These additional tooth germs budded off from ectopic positions along the dental lamina, rather than in an ordered sequence from the successional lamina. Wnt/β-catenin activation enhanced cell proliferation, particularly in normally non-odontogenic regions of the dental lamina, which widely expressed Lef1, restricting the Sox2 domain. This suggests an expansion of the successional lamina at the expense of the dental lamina. Activation of the Wnt/β-catenin pathway in cultured snake dental organs, therefore, led to changes in proliferation and to the molecular pattern of the dental lamina, resulting in loss of the organised emergence of tooth germs. These results suggest that epithelial compartments are critical for the arrangement of organs that develop in sequence, and highlight the role of Wnt/β-catenin signalling in such processes.

  11. Epstein-Barr virus associated modulation of Wnt pathway is not dependent on latent membrane protein-1.

    Directory of Open Access Journals (Sweden)

    Natasha Webb

    2008-09-01

    Full Text Available Previous studies have indicated that Epstein-Barr virus (EBV can modulate the Wnt pathway in virus-infected cells and this effect is mediated by EBV-encoded oncogene latent membrane protein 1 (LMP1. Here we have reassessed the role of LMP1 in regulating the expression of various mediators of the canonical Wnt cascade. Contradicting the previous finding, we found that the levels of E-cadherin, beta-catenin, Glycogen Synthase Kinase 3ss (GSK3beta, axin and alpha-catenin were not affected by the expression of LMP1 sequences from normal B cells or nasopharyngeal carcinoma. Moreover, we also show that LMP1 expression had no detectable effect on the E-cadherin and beta-catenin interaction and did not induce transcriptional activation of beta-catenin. Taken together these studies demonstrate that EBV-mediated activation of Wnt pathway is not dependent on the expression of LMP1.

  12. Secreted and Transmembrane Wnt Inhibitors and Activators

    Science.gov (United States)

    Cruciat, Cristina-Maria; Niehrs, Christof

    2013-01-01

    Signaling by the Wnt family of secreted glycoproteins plays important roles in embryonic development and adult homeostasis. Wnt signaling is modulated by a number of evolutionarily conserved inhibitors and activators. Wnt inhibitors belong to small protein families, including sFRP, Dkk, WIF, Wise/SOST, Cerberus, IGFBP, Shisa, Waif1, APCDD1, and Tiki1. Their common feature is to antagonize Wnt signaling by preventing ligand–receptor interactions or Wnt receptor maturation. Conversely, the Wnt activators, R-spondin and Norrin, promote Wnt signaling by binding to Wnt receptors or releasing a Wnt-inhibitory step. With few exceptions, these antagonists and agonists are not pure Wnt modulators, but also affect additional signaling pathways, such as TGF-β and FGF signaling. Here we discuss their interactions with Wnt ligands and Wnt receptors, their role in developmental processes, as well as their implication in disease. PMID:23085770

  13. HIV-1 protein induced modulation of primary human osteoblast differentiation and function via a Wnt/β-catenin-dependent mechanism.

    LENUS (Irish Health Repository)

    Butler, Joseph S

    2013-02-01

    HIV infection is associated with metabolic bone disease resulting in bone demineralization and reduced bone mass. The molecular mechanisms driving this disease process have yet to be elucidated. Wnt\\/β-catenin signaling plays a key role in bone development and remodeling. We attempted to determine the effects of the HIV-1 protein, gp120, on Wnt\\/β-catenin signaling at an intracellular and transcriptional level in primary human osteoblasts (HOBs). This work, inclusive of experimental controls, was part of a greater project assessing the effects of a variety of different agents on Wnt\\/β-catenin signaling (BMC Musculoskelet Disord 2010;11:210).We examined the phenotypic effects of silencing and overexpressing the Wnt antagonist, Dickkopf-1 (Dkk1) in HOBs treated with gp120. HOBs exposed to gp120 displayed a significant reduction in alkaline phosphatase activity (ALP) activity and cell proliferation and increased cellular apoptosis over a 48 h time course. Immunocytochemistry demonstrated a significant reduction in intracytosolic and intranuclear β-catenin in response to HIV-1 protein exposure. These changes were associated with a reduction of TCF\\/LEF-mediated transcription, the transcriptional outcome of canonical Wnt β-catenin signaling. Silencing Dkk1 expression in HOBs exposed to gp120 resulted in increased ALP activity and cell proliferation, and decreased cellular apoptosis relative to scrambled control. Dkk1 overexpression exacerbated the inhibitory effect of gp120 on HOB function, with decreases in ALP activity and cell proliferation and increased cellular apoptosis relative to vector control. Wnt\\/β-catenin signaling plays a key regulatory role in HIV-associated bone loss, with Dkk1, aputative central mediator in this degenerative process. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 218-226, 2013.

  14. Heterotrimeric G protein-dependent WNT-5A signaling to ERK1/2 mediates distinct aspects of microglia proinflammatory transformation

    Directory of Open Access Journals (Sweden)

    Halleskog Carina

    2012-05-01

    Full Text Available Abstract Background WNT-5A signaling in the central nervous system is important for morphogenesis, neurogenesis and establishment of functional connectivity; the source of WNT-5A and its importance for cellular communication in the adult brain, however, are mainly unknown. We have previously investigated the inflammatory effects of WNT/β-catenin signaling in microglia in Alzheimer's disease. WNT-5A, however, generally recruits β-catenin-independent signaling. Thus, we aim here to characterize the role of WNT-5A and downstream signaling pathways for the inflammatory transformation of the brain's macrophages, the microglia. Methods Mouse brain sections were used for immunohistochemistry. Primary isolated microglia and astrocytes were employed to characterize the WNT-induced inflammatory transformation and underlying intracellular signaling pathways by immunoblotting, quantitative mRNA analysis, proliferation and invasion assays. Further, measurements of G protein activation by [γ-35 S]GTP binding, examination of calcium fluxes and cyclic AMP production were used to define intracellular signaling pathways. Results Astrocytes in the adult mouse brain express high levels of WNT-5A, which could serve as a novel astroglia-microglia communication pathway. The WNT-5A-induced proinflammatory microglia response is characterized by increased expression of inducible nitric oxide synthase, cyclooxygenase-2, cytokines, chemokines, enhanced invasive capacity and proliferation. Mapping of intracellular transduction pathways reveals that WNT-5A activates heterotrimeric Gi/o proteins to reduce cyclic AMP levels and to activate a Gi/o protein/phospholipase C/calcium-dependent protein kinase/extracellular signal-regulated kinase 1/2 (ERK1/2 axis. We show further that WNT-5A-induced ERK1/2 signaling is responsible for distinct aspects of the proinflammatory transformation, such as matrix metalloprotease 9/13 expression, invasion and proliferation. Conclusions

  15. Updating the Wnt pathways

    Science.gov (United States)

    Yu, Jia; Virshup, David M.

    2014-01-01

    In the three decades since the discovery of the Wnt1 proto-oncogene in virus-induced mouse mammary tumours, our understanding of the signalling pathways that are regulated by the Wnt proteins has progressively expanded. Wnts are involved in an complex signalling network that governs multiple biological processes and cross-talk with multiple additional signalling cascades, including the Notch, FGF (fibroblast growth factor), SHH (Sonic hedgehog), EGF (epidermal growth factor) and Hippo pathways. The Wnt signalling pathway also illustrates the link between abnormal regulation of the developmental processes and disease manifestation. Here we provide an overview of Wnt-regulated signalling cascades and highlight recent advances. We focus on new findings regarding the dedicated Wnt production and secretion pathway with potential therapeutic targets that might be beneficial for patients with Wnt-related diseases. PMID:25208913

  16. Kinesin superfamily protein Kif26b links Wnt5a-Ror signaling to the control of cell and tissue behaviors in vertebrates.

    Science.gov (United States)

    Susman, Michael W; Karuna, Edith P; Kunz, Ryan C; Gujral, Taranjit S; Cantú, Andrea V; Choi, Shannon S; Jong, Brigette Y; Okada, Kyoko; Scales, Michael K; Hum, Jennie; Hu, Linda S; Kirschner, Marc W; Nishinakamura, Ryuichi; Yamada, Soichiro; Laird, Diana J; Jao, Li-En; Gygi, Steven P; Greenberg, Michael E; Ho, Hsin-Yi Henry

    2017-09-08

    Wnt5a-Ror signaling constitutes a developmental pathway crucial for embryonic tissue morphogenesis, reproduction and adult tissue regeneration, yet the molecular mechanisms by which the Wnt5a-Ror pathway mediates these processes are largely unknown. Using a proteomic screen, we identify the kinesin superfamily protein Kif26b as a downstream target of the Wnt5a-Ror pathway. Wnt5a-Ror, through a process independent of the canonical Wnt/β-catenin-dependent pathway, regulates the cellular stability of Kif26b by inducing its degradation via the ubiquitin-proteasome system. Through this mechanism, Kif26b modulates the migratory behavior of cultured mesenchymal cells in a Wnt5a-dependent manner. Genetic perturbation of Kif26b function in vivo caused embryonic axis malformations and depletion of primordial germ cells in the developing gonad, two phenotypes characteristic of disrupted Wnt5a-Ror signaling. These findings indicate that Kif26b links Wnt5a-Ror signaling to the control of morphogenetic cell and tissue behaviors in vertebrates and reveal a new role for regulated proteolysis in noncanonical Wnt5a-Ror signal transduction.

  17. 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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    Highlights: ► Wnt5a is identified in osteoblasts in tibial growth plate and bone marrow. ► Osteoblastic differentiation is associated with increased expression of Wnt5a/Ror2. ► Wnt5a/Ror2 signaling is important for BMP-2-mediated osteoblastic differentiation. ► 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 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.

  19. Induction of CXC chemokines in human mesenchymal stem cells by stimulation with secreted frizzled-related proteins through non-canonical Wnt signaling.

    Science.gov (United States)

    Bischoff, David S; Zhu, Jian-Hua; Makhijani, Nalini S; Yamaguchi, Dean T

    2015-12-26

    To investigate the effect of secreted frizzled-related proteins (sFRPs) on CXC chemokine expression in human mesenchymal stem cells (hMSCs). CXC chemokines such as CXCL5 and CXCL8 are induced in hMSCs during differentiation with osteogenic differentiation medium (OGM) and may be involved in angiogenic stimulation during bone repair. hMSCs were treated with conditioned medium (CM) from L-cells expressing non-canonical Wnt5a protein, or with control CM from wild type L-cells, or directly with sFRPs for up to 10 d in culture. mRNA expression levels of both CXCL5 and CXCL8 were quantitated by real-time reverse transcriptase-polymerase chain reaction and secreted protein levels of these proteins determined by ELISA. Dose- (0-500 ng/mL) and time-response curves were generated for treatment with sFRP1. Signal transduction pathways were explored by western blot analysis with pan- or phosphorylation-specific antibodies, through use of specific pathway inhibitors, and through use of siRNAs targeting specific frizzled receptors (Fzd)-2 and 5 or the receptor tyrosine kinase-like orphan receptor-2 (RoR2) prior to treatment with sFRPs. CM from L-cells expressing Wnt5a, a non-canonical Wnt, stimulated an increase in CXCL5 mRNA expression and protein secretion in comparison to control L-cell CM. sFRP1, which should inhibit both canonical and non-canonical Wnt signaling, surprisingly enhanced the expression of CXCL5 at 7 and 10 d. Dickkopf1, an inhibitor of canonical Wnt signaling prevented the sFRP-stimulated induction of CXCL5 and actually inhibited basal levels of CXCL5 expression at 7 but not at 10 d post treatment. In addition, all four sFRPs isoforms induced CXCL8 expression in a dose- and time-dependent manner with maximum expression at 7 d with treatment at 150 ng/mL. The largest increases in CXCL5 expression were seen from stimulation with sFRP1 or sFRP2. Analysis of mitogen-activated protein kinase signaling pathways in the presence of OGM showed sFRP1-induced

  20. [The role of Wnt/β-catenin pathway and LRP5 protein in metabolism of bone tissue and osteoporosis etiology].

    Science.gov (United States)

    Wolski, Hubert; Drwęska-Matelska, Natalia; Seremak-Mrozikiewicz, Agnieszka; Łowicki, Zdzisław; Czerny, Bogusław

    2015-04-01

    Osteoporosis is a metabolic bone disease, manifested by decreased bone mineral density microarchitectural disturbances of bone tissue, and increased risk of bone fractures. Owing to large-scale morbidity particularly among postmenopausal women, nowadays osteoporosis constitutes a significant global health problem. In recent years, much attention has been paid to the role of signaling Wnt/β-catenin pathway and LRP protein in the pathomechanism of osteoporosis, indicating a possible contribution of polymorphic variants of the candidate LRP5 gene to disease development. The goal of our study is to present contemporary research on signaling Wnt/β-catenin pathway and mechanism of LRP protein action in the process of bone tissue metabolism and etiology of osteoporosis.

  1. Role of WNT signaling in epididymal sperm maturation.

    Science.gov (United States)

    Cheng, Jin-Mei; Tang, Ji-Xin; Li, Jian; Wang, Yu-Qian; Wang, Xiu-Xia; Zhang, Yan; Chen, Su-Ren; Liu, Yi-Xun

    2018-02-01

    Spermatozoa maturation, a process required for spermatozoa to acquire progressive motility and the ability to fertilize ova, primarily occurs in the caput and corpus of the epididymis. Despite considerable efforts, the factor(s) promoting epididymal sperm maturation remains unclear. Recently, WNT signaling has been implicated in epididymal sperm maturation. To further investigate WNT signaling function in epididymal sperm maturation, we generated Wntless conditional knockout mice (Wls cKO), Wls flox/flox ; Lcn5-Cre. In these mice, WNTLESS (WLS), a conserved membrane protein required for all WNT protein secretion, was specifically disrupted in the principal cells of the caput epididymidis. Immunoblot analysis showed that WLS was significantly reduced in the caput epididymidis of Wls cKO mice. In the caput epididymidis of Wls cKO mice, WNT 10A and WNT 2b, which are typically secreted by the principal cells of the caput epididymis, were not secreted. Interestingly, sperm motility analysis showed that the WLS deficiency in the caput epididymidis had no effect on sperm motility. Moreover, fertility tests showed that Wls cKO male mice had normal fertility. These results indicate that the disruption of WLS in principal cells of the caput epididymidis inhibits WNT protein secretion but has no effect on sperm motility and male fertility, suggesting that WNT signaling in the caput epididymidis may be dispensable for epididymal sperm maturation in mice.

  2. The role of protein phosphatase 2A in regulating Wnt signaling and apoptosis

    Science.gov (United States)

    Li, Xinghai

    Protein phosphatase 2A (PP2A) is a major serine/threonine-specific phosphatase and regulates a significant array of cellular events. This dissertation primarily describes the novel role of PP2A in Wnt signaling and apoptosis. First, PP2A and its B56 regulatory subunit inhibit Wnt signaling in Xenopus. PP2A is required for β- catenin degradation in vitro. A PP2A heterotrimer containing A, C, and B56 subunits was co- immunoprecipitated with axin. A, C, and B56 subunits each have ventralizing ability in Xenopus embryos. B56 was epistatically positioned downstream of GSK3β and axin but upstream of β-catenin. Second, B56-targeted PP2A is required for survival and protects from apoptosis in Drosophila. Loss of A, C, or B56 subunits by RNA interference (RNAi) induced apoptosis in S2 cells, which requires the presence of specific caspases. Epistasis analysis placed B56-targeted PP2A functionally upstream of Apaf-1, Reaper and Hid, and p53. Loss of B56-targeted PP2A in Drosophila embryos by RNAi resulted in abortion of embryo development and this phenotype was rescued by co-RNAi of Drice. Third, two conserved domains in B subunits mediate binding to the A subunit of PP2A. B subunits have no detectable sequence homology among different families. In vitro expression of a series of B56α fragments identified two distinct domains that independently bound to the A subunit. Sequence alignment of these A subunit-binding domains recognized conserved residues in B/PR55 and B'/PR72 family members that serve a similar function. Fourth, to examine whether the B56β gene within 11q12 is a tumor suppressor mutated in neuroblastoma, the DNA and RNA samples from neuroblastoma patients and cell lines were analyzed and no mutations were identified in the coding regions of the B56β gene. Finally, to identify novel regulatory subunits of PP2A in S. cerevisiae , biochemical approaches for purifying PP2A-associated novel regulators were undertaken. Although the A and C subunit complex in the

  3. A p38 Mitogen-Activated Protein Kinase-Regulated Myocyte Enhancer Factor 2–β-Catenin Interaction Enhances Canonical Wnt Signaling

    Science.gov (United States)

    Ehyai, Saviz; Dionyssiou, Mathew G.; Gordon, Joseph W.; Williams, Declan; Siu, K. W. Michael

    2015-01-01

    Canonical Wnt/β-catenin signaling plays a major role in various biological contexts, such as embryonic development, cell proliferation, and cancer progression. Previously, a connection between p38 mitogen-activated protein kinase (MAPK) signaling and Wnt-mediated activation of β-catenin was implied but poorly understood. In the present study, we investigated potential cross talk between p38 MAPK and Wnt/β-catenin signaling. Here we show that a loss of p38 MAPK α/β function reduces β-catenin nuclear accumulation in Wnt3a-stimulated primary vascular smooth muscle cells (VSMCs). Conversely, active p38 MAPK signaling increases β-catenin nuclear localization and target gene activity in multiple cell types. Furthermore, the effect of p38 MAPK α/β on β-catenin activity is mediated through phosphorylation of a key p38 MAPK target, myocyte enhancer factor 2 (MEF2). Here we report a p38 MAPK-mediated, phosphorylation-dependent interaction between MEF2 and β-catenin in multiple cell types and primary VSMCs that results in (i) increased β-catenin nuclear retention, which is reversed by small interfering RNA (siRNA)-mediated MEF2 gene silencing; (ii) increased activation of MEF2 and Wnt/β-catenin target genes; and (iii) increased Wnt-stimulated cell proliferation. These observations provide mechanistic insight into a fundamental level of cross talk between p38 MAPK/MEF2 signaling and canonical Wnt signaling. PMID:26552705

  4. Nonalcoholic fatty liver disease induced by noncanonical Wnt and its rescue by Wnt3a

    Science.gov (United States)

    Wang, Shuxia; Song, Kangxing; Srivastava, Roshni; Dong, Chao; Go, Gwang-Woong; Li, Na; Iwakiri, Yasuko; Mani, Arya

    2015-01-01

    Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, which begins with isolated steatosis and advances to nonalcoholic steatohepatitis (NASH), steatofibrosis, and cirrhosis. The pathways involved in disease progression are not understood. Loss-of-function mutations in Wnt coreceptor LDL receptor-related protein 6 (LRP6) underlie early-onset atherosclerosis, metabolic risk factors, and NAFLD in humans by unknown mechanisms. We generated mice with the human disease-associated LRP6R611C mutation and phenotypically characterized their liver. Homozygote LRP6R611C (LRP6mut/mut) mice exhibited both steatohepatitis and steatofibrosis. These traits were associated with increased activity of the noncanonical Wnt/Ras homolog family member A, Rho-associated protein kinase 2, and PKC-α/-μ pathways. Accordingly, there was increased TGF-β1 activity, coupled with enhanced expression of smooth muscle α-actin and vimentin that colocalized with albumin in LRP6mut/mut mouse liver. LRP6 knockdown reprogramed HepG2 cells to express both these markers, linking impaired Wnt signaling with hepatocyte transdifferentiation. The causal link between altered Wnt signaling and NASH was established by normalization of the disease pathways and rescue of the liver traits by Wnt3a administration to LRP6mut/mut mice. Thus, this study identifies diverse disease pathways that underlie a spectrum of NASH-related liver diseases and are linked by a single human genetic variant. LRP6 and noncanonical Wnt pathways are important potential therapeutic targets against NASH.—Wang, S., Song, K., Srivastava, R., Dong, C., Go, G.-W., Li, N., Iwakiri, Y., Mani, A. Nonalcoholic fatty liver disease induced by noncanonical Wnt and its rescue by Wnt3a. PMID:25917329

  5. Vaccinia virus protein A49 activates Wnt signalling by targetting the E3 ligase β-TrCP

    Science.gov (United States)

    Maluquer de Motes, Carlos; Smith, Geoffrey L.

    2017-01-01

    Vaccinia virus (VACV) encodes multiple proteins inhibiting the NF-κB signalling pathway. One of these, A49, targets the E3 ubiquitin ligase β-TrCP, which is responsible for the ubiquitylation and consequential proteosomal degradation of IκBα and the release of the NF-κB heterodimer. β-TrCP is a pleiotropic enzyme ubiquitylating multiple cellular substrates, including the transcriptional activator β-catenin. Here we demonstrate that A49 can activate the Wnt signalling pathway, a critical pathway that is involved in cell cycle and cell differentiation, and is controlled by β-catenin. The data presented show that the expression of A49 ectopically or during VACV infection causes accumulation of β-catenin, and that A49 triggering of Wnt signalling is dependent on binding β-TrCP. This is consistent with A49 blocking the ability of β-TrCP to recognise β-catenin and IκBα, and possibly other cellular targets. Thus, A49 targetting of β-TrCP affects multiple cellular pathways, including the NF-κB and Wnt signalling cascades. PMID:29058646

  6. Novel Wnt Regulator NEL-Like Molecule-1 Antagonizes Adipogenesis and Augments Osteogenesis Induced by Bone Morphogenetic Protein 2

    Science.gov (United States)

    Shen, Jia; James, Aaron W.; Zhang, Xinli; Pang, Shen; Zara, Janette N.; Asatrian, Greg; Chiang, Michael; Lee, Min; Khadarian, Kevork; Nguyen, Alan; Lee, Kevin S.; Siu, Ronald K.; Tetradis, Sotirios; Ting, Kang; Soo, Chia

    2017-01-01

    The differentiation factor NEL-like molecule-1 (NELL-1) has been reported as osteoinductive in multiple in vivo preclinical models. Bone morphogenetic protein (BMP)-2 is used clinically for skeletal repair, but in vivo administration can induce abnormal, adipose-filled, poor-quality bone. We demonstrate that NELL-1 combined with BMP2 significantly optimizes osteogenesis in a rodent femoral segmental defect model by minimizing the formation of BMP2-induced adipose-filled cystlike bone. In vitro studies using the mouse bone marrow stromal cell line M2-10B4 and human primary bone marrow stromal cells have confirmed that NELL-1 enhances BMP2-induced osteogenesis and inhibits BMP2-induced adipogenesis. Importantly, the ability of NELL-1 to direct BMP2-treated cells toward osteogenesis and away from adipogenesis requires intact canonical Wnt signaling. Overall, these studies establish the feasibility of combining NELL-1 with BMP2 to improve clinical bone regeneration and provide mechanistic insight into canonical Wnt pathway activity during NELL-1 and BMP2 osteogenesis. The novel abilities of NELL-1 to stimulate Wnt signaling and to repress adipogenesis may highlight new treatment approaches for bone loss in osteoporosis. PMID:26772960

  7. Wnt Lipidation and Modifiers in Intestinal Carcinogenesis and Cancer

    Directory of Open Access Journals (Sweden)

    Elke Kaemmerer

    2016-07-01

    Full Text Available The wingless (Wnt signaling is suggested as a fundamental hierarchical pathway in regulation of proliferation and differentiation of cells. The Wnt ligands are small proteins of about 40 kDa essentially for regulation and initiation of the Wnt activity. They are secreted proteins requiring acylation for activity in the Wnt signaling cascade and for functional interactivity with transmembrane proteins. Dual lipidation is important for posttranslational activation of the overwhelming number of Wnt proteins and is probably involved in their spatial distribution. The intestinal mucosa, where Wnt signaling is essential in configuration and maintenance, is an established model to study Wnt proteins and their role in carcinogenesis and cancer. The intestinal crypt-villus/crypt-plateau axis, a cellular system with self-renewal, proliferation, and differentiation, is tightly coordinated by a Wnt gradient. In the review, some attention is given to Wnt3, Wnt3A, and Wnt2B as important members of the Wnt family to address the role of lipidation and modifiers of Wnt proteins in intestinal carcinogenesis. Wnt3 is an important player in establishing the Wnt gradient in intestinal crypts and is mainly produced by Paneth cells. Wnt2B is characterized as a mitochondrial protein and shuttles between mitochondria and the nucleus. Porcupine and ACSL5, a long-chain fatty acid activating enzyme, are introduced as modifiers of Wnts and as interesting strategy to targeting Wnt-driven carcinogenesis.

  8. Unraveling the Wnt secretion pathway

    NARCIS (Netherlands)

    Harterink, M.

    2011-01-01

    The Wnt family of signaling proteins has essential functions in development and adult tissue homeostasis throughout the animal kingdom. Although signaling cascades triggered by Wnt proteins have been extensively studied, much remains to be learned about how Wnts are produced and secreted and how

  9. The low-density lipoprotein receptor-related protein 10 is a negative regulator of the canonical Wnt/β-catenin signaling pathway

    International Nuclear Information System (INIS)

    Jeong, Young-Hee; Sekiya, Manami; Hirata, Michiko; Ye, Mingjuan; Yamagishi, Azumi; Lee, Sang-Mi; Kang, Man-Jong; Hosoda, Akemi; Fukumura, Tomoe; Kim, Dong-Ho; Saeki, Shigeru

    2010-01-01

    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/β-catenin signaling. Here, we found that LRP10, a new member of the LDLR gene family, inhibits the canonical Wnt/β-catenin signaling pathway. The β-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 GSK3β phosphorylation was inhibited by incubation with lithium chloride and co-transfection with constitutively active S33Y-mutated β-catenin. Nuclear β-catenin accumulation was unaffected by LRP10. The present studies suggest that LRP10 may interfere with the formation of the β-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/β-catenin signaling pathway.

  10. 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.

  11. Gene expression profiling of low-grade endometrial stromal sarcoma indicates fusion protein-mediated activation of the Wnt signaling pathway.

    Science.gov (United States)

    Przybyl, Joanna; Kidzinski, Lukasz; Hastie, Trevor; Debiec-Rychter, Maria; Nusse, Roel; van de Rijn, Matt

    2018-05-01

    Low-grade endometrial stromal sarcomas (LGESS) harbor chromosomal translocations that affect proteins associated with chromatin remodeling Polycomb Repressive Complex 2 (PRC2), including SUZ12, PHF1 and EPC1. Roughly half of LGESS also demonstrate nuclear accumulation of β-catenin, which is a hallmark of Wnt signaling activation. However, the targets affected by the fusion proteins and the role of Wnt signaling in the pathogenesis of these tumors remain largely unknown. Here we report the results of a meta-analysis of three independent gene expression profiling studies on LGESS and immunohistochemical evaluation of nuclear expression of β-catenin and Lef1 in 112 uterine sarcoma specimens obtained from 20 LGESS and 89 LMS patients. Our results demonstrate that 143 out of 310 genes overexpressed in LGESS are known to be directly regulated by SUZ12. In addition, our gene expression meta-analysis shows activation of multiple genes implicated in Wnt signaling. We further emphasize the role of the Wnt signaling pathway by demonstrating concordant nuclear expression of β-catenin and Lef1 in 7/16 LGESS. Based on our findings, we suggest that LGESS-specific fusion proteins disrupt the repressive function of the PRC2 complex similar to the mechanism seen in synovial sarcoma, where the SS18-SSX fusion proteins disrupt the mSWI/SNF (BAF) chromatin remodeling complex. We propose that these fusion proteins in LGESS contribute to overexpression of Wnt ligands with subsequent activation of Wnt signaling pathway and formation of an active β-catenin/Lef1 transcriptional complex. These observations could lead to novel therapeutic approaches that focus on the Wnt pathway in LGESS. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. The crystal structure of full-length Sizzled from Xenopus laevis yields insights into Wnt-antagonistic function of secreted Frizzled-related proteins.

    Science.gov (United States)

    Bu, Qixin; Li, Zhiqiang; Zhang, Junying; Xu, Fei; Liu, Jianmei; Liu, Heli

    2017-09-29

    The Wnt-signaling pathway is crucial to cell proliferation, differentiation, and migration. The secreted Frizzled-related proteins (sFRPs) represent the largest family of secreted Wnt inhibitors. However, their function in antagonizing Wnt signaling has remained somewhat controversial. Here, we report the crystal structure of Sizzled from Xenopus laevis , the first full-length structure of an sFRP. Tethered by an inter-domain disulfide bond and a linker, the N-terminal cysteine-rich domain (CRD) and the C-terminal netrin-like domain (NTR) of Sizzled are arranged in a tandem fashion, with the NTR domain occluding the groove of CRD for Wnt accessibility. A Dual-Luciferase assay demonstrated that removing the NTR domain and replacing the CRD groove residues His-116 and His-118 with aromatic residues may significantly enhance antagonistic function of Sizzled in inhibiting Wnt3A signaling. Sizzled is a monomer in solution, and Sizzled CRD exhibited different packing in the crystal, suggesting that sFRPs do not have a conserved CRD dimerization mode. Distinct from the canonical NTR domain, the Sizzled NTR adopts a novel α/β folding with two perpendicular helices facing the central mixed β-sheet. The subgroup of human sFRP1/2/5 and Sizzled should have a similar NTR domain that features a highly positively charged region, opposite the NTR-CRD interface, suggesting that the NTR domain in human sFRPs, at least sFRP1/2/5, is unlikely to bind to Wnt but is likely involved in biphasic Wnt signaling modulation. In summary, the Sizzled structure provides the first insights into how the CRD and the NTR domains relate to each other for modulating Wnt-antagonistic function of sFRPs. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Decreased Wnt4 expression inhibits thymoma development through downregulation of FoxN1

    Science.gov (United States)

    Chen, Yuan; Liu, Xin; Liu, Yimei; Wang, Yuanguo; Wang, Hai; Lu, Chao

    2017-01-01

    Background The Wnt signaling pathway controls the development of thymic epithelial cells by regulating the expression of FoxN1. Thymoma is a type of malignant tumor arising from the thymic epithelial cells. To determine whether Wnt4 and FoxN1 are involved in the pathogenesis of thymoma, this study determined the mRNA and protein levels of Wnt4 and Foxn1 in thymoma, and analyzed the effect of thymoma cell apoptosis and tumor growth in nude mice after Wnt4 and FoxN1 downregulation. Methods Wnt4 and FoxN1 mRNA and protein levels in thymoma tissues were analyzed by RT-qPCR and immunohistochemistry, respectively. Thymoma cells were cultured and transfected with siRNA targeting the Wnt4, JNK, and FoxN1 genes. Apoptosis of thymoma cells were analyzed after Wnt4 and FoxN1 downregulation. In addition, thymoma cells were inoculated into nude mice and tumor growth was analyzed. Results The rates of expression of Wnt4 and FoxN1 protein were 64.3% and 58.9%, while the levels of mRNA expression were 2.56±0.04 and 1.83±0.11, respectively. With increasing malignancy of thymoma, the rates of positivity for Wnt4 and FoxN1 mRNA and protein expression gradually increased. Upon interfering with Wnt4, JNK, and FoxN1 gene expression by using siRNA technology, the inhibition rates were 56.7%, 72.6%, and 63.2%, respectively. The expression of FoxN1 mRNA and protein was decreased after Wnt4 and JNK downregulation. After downregulation of Wnt4 and FoxN1 gene expression, the apoptosis rate of thymoma cells increased and the tumor volume decreased in nude mice. Conclusions High expression of Wnt4 and FoxN1 may play an important role in the generation and development of thymoma. The FoxN1 gene produced a marked downstream effect through the regulation of Wnt4. Determining the positivity for both Wnt4 and FoxN1 can help us to evaluate the level of malignancy of thymoma. PMID:28740671

  14. Data on chemical activation of Wnt/β-catenin during axolotl limb regeneration.

    Science.gov (United States)

    Wischin, Sabina; Castañeda-Patlán, Cristina; Robles-Flores, Martha; Chimal-Monroy, Jesús

    2017-04-01

    Limb amputation in axolotls was performed to obtain data demonstrating that a chemical agonist of Wnt (int-related protein)/β-catenin signalling can have a role in axolotl limb regeneration (Wischin et al., 2017) [1]. The data revealed that active β-catenin protein was present during limb regeneration in some Leydig cells in the epithelium; after the chemical treatment, it was observed in more Leydig cells. In addition, the chemical agonist of Wnt generated distinct limb malformation.

  15. Mitogen-Activated Protein Kinases Promote WNT/beta-Catenin Signaling via Phosphorylation of LRP6

    Czech Academy of Sciences Publication Activity Database

    Červenka, I.; Wolf, J.; Mašek, J.; Krejčí, Pavel; Wilcox, W. R.; Kozubík, Alois; Schulte, G.; Gutkind, J.S.; Bryja, Vítězslav

    2011-01-01

    Roč. 31, č. 1 (2011), s. 179-189 ISSN 0270-7306 R&D Projects: GA ČR(CZ) GC204/09/J030 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Institutional support: RVO:68081707 Keywords : WNT RECEPTOR ACTIVATION * BETA-CATENIN * CORECEPTOR LRP6 Subject RIV: BO - Biophysics Impact factor: 5.527, year: 2011

  16. The non-canonical Wnt/PKC pathway regulates mitochondrial dynamics through degradation of the arm-like domain-containing protein Alex3.

    Directory of Open Access Journals (Sweden)

    Román Serrat

    Full Text Available The regulation of mitochondrial dynamics is vital in complex cell types, such as neurons, that transport and localize mitochondria in high energy-demanding cell domains. The Armcx3 gene encodes a mitochondrial-targeted protein (Alex3 that contains several arm-like domains. In a previous study we showed that Alex3 protein regulates mitochondrial aggregation and trafficking. Here we studied the contribution of Wnt proteins to the mitochondrial aggregation and dynamics regulated by Alex3. Overexpression of Alex3 in HEK293 cells caused a marked aggregation of mitochondria, which was attenuated by treatment with several Wnts. We also found that this decrease was caused by Alex3 degradation induced by Wnts. While the Wnt canonical pathway did not alter the pattern of mitochondrial aggregation induced by Alex3, we observed that the Wnt/PKC non-canonical pathway regulated both mitochondrial aggregation and Alex3 protein levels, thereby rendering a mitochondrial phenotype and distribution similar to control patterns. Our data suggest that the Wnt pathway regulates mitochondrial distribution and dynamics through Alex3 protein degradation.

  17. The Non-Canonical Wnt/PKC Pathway Regulates Mitochondrial Dynamics through Degradation of the Arm-Like Domain-Containing Protein Alex3

    Science.gov (United States)

    Mirra, Serena; Quevedo, Martí; Garcia-Fernàndez, Jordi; Ulloa, Fausto; Burgaya, Ferrán; Soriano, Eduardo

    2013-01-01

    The regulation of mitochondrial dynamics is vital in complex cell types, such as neurons, that transport and localize mitochondria in high energy-demanding cell domains. The Armcx3 gene encodes a mitochondrial-targeted protein (Alex3) that contains several arm-like domains. In a previous study we showed that Alex3 protein regulates mitochondrial aggregation and trafficking. Here we studied the contribution of Wnt proteins to the mitochondrial aggregation and dynamics regulated by Alex3. Overexpression of Alex3 in HEK293 cells caused a marked aggregation of mitochondria, which was attenuated by treatment with several Wnts. We also found that this decrease was caused by Alex3 degradation induced by Wnts. While the Wnt canonical pathway did not alter the pattern of mitochondrial aggregation induced by Alex3, we observed that the Wnt/PKC non-canonical pathway regulated both mitochondrial aggregation and Alex3 protein levels, thereby rendering a mitochondrial phenotype and distribution similar to control patterns. Our data suggest that the Wnt pathway regulates mitochondrial distribution and dynamics through Alex3 protein degradation. PMID:23844091

  18. Targeting Wnt signaling in colorectal cancer. A Review in the Theme: Cell Signaling: Proteins, Pathways and Mechanisms

    Science.gov (United States)

    Novellasdemunt, Laura; Antas, Pedro

    2015-01-01

    The evolutionarily conserved Wnt signaling pathway plays essential roles during embryonic development and tissue homeostasis. Notably, comprehensive genetic studies in Drosophila and mice in the past decades have demonstrated the crucial role of Wnt signaling in intestinal stem cell maintenance by regulating proliferation, differentiation, and cell-fate decisions. Wnt signaling has also been implicated in a variety of cancers and other diseases. Loss of the Wnt pathway negative regulator adenomatous polyposis coli (APC) is the hallmark of human colorectal cancers (CRC). Recent advances in high-throughput sequencing further reveal many novel recurrent Wnt pathway mutations in addition to the well-characterized APC and β-catenin mutations in CRC. Despite attractive strategies to develop drugs for Wnt signaling, major hurdles in therapeutic intervention of the pathway persist. Here we discuss the Wnt-activating mechanisms in CRC and review the current advances and challenges in drug discovery. PMID:26289750

  19. Expression patterns of Wnt genes during development of an anterior part of the chicken eye

    OpenAIRE

    Fokina, Valentina M.; Frolova, Elena I.

    2006-01-01

    To address the roles of Wnts in the development of the anterior eye, we used a chicken model to perform comprehensive expression analysis of all Wnt genes during anterior eye development. In analyzing the available genomic sequences, we found that the chicken genome encodes 18 Wnt proteins that are homologous to corresponding human and mouse proteins. The mRNA sequences for 12 chicken Wnt genes are available in GenBank, and mRNAs for six other Wnt genes (Wnt2, Wnt5b, Wnt7b, Wnt8b, Wnt9b and W...

  20. A SNX3-dependent retromer pathway mediates retrograde transport of the Wnt sorting receptor Wntless and is required for Wnt secretion

    NARCIS (Netherlands)

    Harterink, M.; Port, F.; Lorenowicz, M.J.; McGough, I.J.; Silhankova, M.; Betist, M.C.; van Weering, J.R.; van Heesbeen, R.G.; Middelkoop, T.C.; Basler, K.; Cullen, P.J.; Korswagen, H.C.

    2011-01-01

    Wnt proteins are lipid-modified glycoproteins that play a central role in development, adult tissue homeostasis and disease. Secretion of Wnt proteins is mediated by the Wnt-binding protein Wntless (Wls), which transports Wnt from the Golgi network to the cell surface for release. It has recently

  1. Wnt signaling requires retromer-dependent recycling of MIG-14/Wntless in Wnt-producing cells.

    NARCIS (Netherlands)

    Yang, P.T.; Lorenowicz, M.J.; Silhankova, M.; Coudreuse, D.Y.M.; Betist, M.C.; Korswagen, H.C.

    2008-01-01

    Wnt proteins are secreted signaling molecules that play a central role in development and adult tissue homeostasis. We have previously shown that Wnt signaling requires retromer function in Wnt-producing cells. The retromer is a multiprotein complex that mediates endosome-to-Golgi transport of

  2. Diabetes Impairs Wnt3 Protein-induced Neurogenesis in Olfactory Bulbs via Glutamate Transporter 1 Inhibition.

    Science.gov (United States)

    Wakabayashi, Tamami; Hidaka, Ryo; Fujimaki, Shin; Asashima, Makoto; Kuwabara, Tomoko

    2016-07-15

    Diabetes is associated with impaired cognitive function. Streptozotocin (STZ)-induced diabetic rats exhibit a loss of neurogenesis and deficits in behavioral tasks involving spatial learning and memory; thus, impaired adult hippocampal neurogenesis may contribute to diabetes-associated cognitive deficits. Recent studies have demonstrated that adult neurogenesis generally occurs in the dentate gyrus of the hippocampus, the subventricular zone, and the olfactory bulbs (OB) and is defective in patients with diabetes. We hypothesized that OB neurogenesis and associated behaviors would be affected in diabetes. In this study, we show that inhibition of Wnt3-induced neurogenesis in the OB causes several behavioral deficits in STZ-induced diabetic rats, including impaired odor discrimination, cognitive dysfunction, and increased anxiety. Notably, the sodium- and chloride-dependent GABA transporters and excitatory amino acid transporters that localize to GABAergic and glutamatergic terminals decreased in the OB of diabetic rats. Moreover, GAT1 inhibitor administration also hindered Wnt3-induced neurogenesis in vitro Collectively, these data suggest that STZ-induced diabetes adversely affects OB neurogenesis via GABA and glutamate transporter systems, leading to functional impairments in olfactory performance. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. A novel gene's role in an ancient mechanism: secreted Frizzled-related protein 1 is a critical component in the anterior-posterior Wnt signaling network that governs the establishment of the anterior neuroectoderm in sea urchin embryos.

    Science.gov (United States)

    Khadka, Anita; Martínez-Bartolomé, Marina; Burr, Stephanie D; Range, Ryan C

    2018-01-01

    The anterior neuroectoderm (ANE) in many deuterostome embryos (echinoderms, hemichordates, urochordates, cephalochordates, and vertebrates) is progressively restricted along the anterior-posterior axis to a domain around the anterior pole. In the sea urchin embryo, three integrated Wnt signaling branches (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC) govern this progressive restriction process, which begins around the 32- to 60-cell stage and terminates by the early gastrula stage. We previously have established that several secreted Wnt modulators of the Dickkopf and secreted Frizzled-related protein families (Dkk1, Dkk3, and sFRP-1/5) are expressed within the ANE and play important roles in modulating the Wnt signaling network during this process. In this study, we use morpholino and dominant-negative interference approaches to characterize the function of a novel Frizzled-related protein, secreted Frizzled-related protein 1 (sFRP-1), during ANE restriction. sFRP-1 appears to be related to a secreted Wnt modulator, sFRP3/4, that is essential to block Wnt signaling and establish the ANE in vertebrates. Here, we show that the sea urchin sFRP3/4 orthologue is not expressed during ANE restriction in the sea urchin embryo. Instead, our results indicate that ubiquitously expressed maternal sFRP-1 and Fzl1/2/7 signaling act together as early as the 32- to 60-cell stage to antagonize the ANE restriction mechanism mediated by Wnt/β-catenin and Wnt/JNK signaling. Then, starting from the blastula stage, Fzl5/8 signaling activates zygotic sFRP-1 within the ANE territory, where it works with the secreted Wnt antagonist Dkk1 (also activated by Fzl5/8 signaling) to antagonize Wnt1/Wnt8-Fzl5/8-JNK signaling in a negative feedback mechanism that defines the outer ANE territory boundary. Together, these data indicate that maternal and zygotic sFRP-1 protects the ANE territory by antagonizing the Wnt1/Wnt8-Fzl5/8-JNK signaling pathway throughout ANE restriction, providing precise

  4. A novel gene’s role in an ancient mechanism: secreted Frizzled-related protein 1 is a critical component in the anterior–posterior Wnt signaling network that governs the establishment of the anterior neuroectoderm in sea urchin embryos

    Directory of Open Access Journals (Sweden)

    Anita Khadka

    2018-01-01

    Full Text Available Abstract The anterior neuroectoderm (ANE in many deuterostome embryos (echinoderms, hemichordates, urochordates, cephalochordates, and vertebrates is progressively restricted along the anterior–posterior axis to a domain around the anterior pole. In the sea urchin embryo, three integrated Wnt signaling branches (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC govern this progressive restriction process, which begins around the 32- to 60-cell stage and terminates by the early gastrula stage. We previously have established that several secreted Wnt modulators of the Dickkopf and secreted Frizzled-related protein families (Dkk1, Dkk3, and sFRP-1/5 are expressed within the ANE and play important roles in modulating the Wnt signaling network during this process. In this study, we use morpholino and dominant-negative interference approaches to characterize the function of a novel Frizzled-related protein, secreted Frizzled-related protein 1 (sFRP-1, during ANE restriction. sFRP-1 appears to be related to a secreted Wnt modulator, sFRP3/4, that is essential to block Wnt signaling and establish the ANE in vertebrates. Here, we show that the sea urchin sFRP3/4 orthologue is not expressed during ANE restriction in the sea urchin embryo. Instead, our results indicate that ubiquitously expressed maternal sFRP-1 and Fzl1/2/7 signaling act together as early as the 32- to 60-cell stage to antagonize the ANE restriction mechanism mediated by Wnt/β-catenin and Wnt/JNK signaling. Then, starting from the blastula stage, Fzl5/8 signaling activates zygotic sFRP-1 within the ANE territory, where it works with the secreted Wnt antagonist Dkk1 (also activated by Fzl5/8 signaling to antagonize Wnt1/Wnt8–Fzl5/8–JNK signaling in a negative feedback mechanism that defines the outer ANE territory boundary. Together, these data indicate that maternal and zygotic sFRP-1 protects the ANE territory by antagonizing the Wnt1/Wnt8–Fzl5/8–JNK signaling pathway throughout ANE

  5. Fresh WNT into the regulation of mitosis.

    Science.gov (United States)

    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.

  6. HCV core protein-induced down-regulation of microRNA-152 promoted aberrant proliferation by regulating Wnt1 in HepG2 cells.

    Directory of Open Access Journals (Sweden)

    Shifeng Huang

    Full Text Available Hepatitis C virus (HCV has been reported to regulate cellular microRNAs (miRNAs. The HCV core protein is considered to be a potential oncoprotein in HCV-related hepatocellular carcinoma (HCV-HCC, but HCV core-regulated miRNAs are largely unknown. Our preliminary experiments revealed significant down-regulation of microRNA-152 (miR-152 by HCV core protein in HepG2 cells. Through target gene prediction softwares, Wnt1 was predicted to be a potential target of miR-152. The present study was initiated to investigate whether miR-152 is aberrantly regulated by the HCV core protein, and involved in the regulation of the aberrant proliferation of HCV-HCC cells.MiR-152 levels were examined by stem-loop real-time RT-PCR (SLqRT-PCR. Cell proliferation was analyzed by MTT and colony formation assay. Cell cycle analysis was performed by flow cytometry. Luciferase reporter assay was conducted to confirm miRNA-target association. Wnt1 expression was determined by real-time qPCR and Western blotting.HCV core protein significantly suppressed miR-152 expression, and led to significant Wnt1 up-regulation with a concomitant aberrantly promoted proliferation. Moreover, we validated that miR-152 inhibition promoted, while miR-152 mimics inhibited cell proliferation. Using, qRT-PCR and western blot, Wnt1 was demonstrated to be regulated by miR-152. Luciferase activity assay showed that while miR-152 mimics significantly reduced the luciferase activity by 83.76% (P<0.0001, miR-152 inhibitor showed no effect on luciferase reporter. Most notably, salvage expression of miR-152 after Ad-HCV core infection for 24 h almost totally reversed the proliferation-promoting effect of the HCV core protein, and meanwhile, reduced the expression of both Wnt1 mRNA and protein to basal levels.These findings provide important evidence that the reduced miR-152 expression by HCV core protein can indirectly lose an inhibitory effect on Wnt1, which might, at least partially lead to cell

  7. WNT Signaling Is Required for Peritoneal Membrane Angiogenesis.

    Science.gov (United States)

    Padwal, Manreet Kaur; Cheng, Genyang; Liu, Limin; Boivin, Felix J; Gangji, Azim; Brimble, Kenneth Scott; Bridgewater, Darren; Margetts, Peter J

    2018-01-24

    The WNT signaling pathway is involved in wound healing and fibrosis. We evaluated the WNT signaling pathway in peritoneal membrane injury. We assessed WNT1 protein expression in the peritoneal effluents of 54 stable peritoneal dialysis (PD) patients and WNT-related gene expression in ex vivo mesothelial cell cultures from 21 PD patients. In a transforming growth factor beta (TGFB) mediated animal model of peritoneal fibrosis, we evaluated regulation of the WNT pathway and the effect of WNT inhibition on peritoneal fibrosis and angiogenesis. WNT1 and WNT2 gene expression were positively correlated with peritoneal membrane solute transport in PD patients. In the mouse peritoneum, TGFΒ-induced peritoneal fibrosis was associated with increased expression of WNT2 and WNT4. Peritoneal b-catenin protein was significantly upregulated after infection with AdTGFB along with elements of the WNT signaling pathway. Treatment with a b-catenin inhibitor (ICG-001) in mice with AdTGFB-induced peritoneal fibrosis resulted in attenuation of peritoneal angiogenesis and reduced vascular endothelial growth factor. Similar results were also observed with the WNT antagonist Dickkopf related protein (DKK) 1. In addition to this, DKK-1 blocked epithelial to mesenchymal transition and increased levels of the cell adhesion protein E-cadherin. We provide evidence that WNT signaling is active in the setting of experimental peritoneal fibrosis and WNT1 correlates with patient peritoneal membrane solute transport in PD patients. Intervention in this pathway is a possible therapy for peritoneal membrane injury.

  8. Enolase 1 (ENO1 and protein disulfide-isomerase associated 3 (PDIA3 regulate Wnt/β-catenin-driven trans-differentiation of murine alveolar epithelial cells

    Directory of Open Access Journals (Sweden)

    Kathrin Mutze

    2015-08-01

    Full Text Available The alveolar epithelium represents a major site of tissue destruction during lung injury. It consists of alveolar epithelial type I (ATI and type II (ATII cells. ATII cells are capable of self-renewal and exert progenitor function for ATI cells upon alveolar epithelial injury. Cell differentiation pathways enabling this plasticity and allowing for proper repair, however, are poorly understood. Here, we applied proteomics, expression analysis and functional studies in primary murine ATII cells to identify proteins and molecular mechanisms involved in alveolar epithelial plasticity. Mass spectrometry of cultured ATII cells revealed a reduction of carbonyl reductase 2 (CBR2 and an increase in enolase 1 (ENO1 and protein disulfide-isomerase associated 3 (PDIA3 protein expression during ATII-to-ATI cell trans-differentiation. This was accompanied by increased Wnt/β-catenin signaling, as analyzed by qRT-PCR and immunoblotting. Notably, ENO1 and PDIA3, along with T1α (podoplanin; an ATI cell marker, exhibited decreased protein expression upon pharmacological and molecular Wnt/β-catenin inhibition in cultured ATII cells, whereas CBR2 levels were stabilized. Moreover, we analyzed primary ATII cells from mice with bleomycin-induced lung injury, a model exhibiting activated Wnt/β-catenin signaling in vivo. We observed reduced CBR2 significantly correlating with surfactant protein C (SFTPC, whereas ENO1 and PDIA3 along with T1α were increased in injured ATII cells. Finally, siRNA-mediated knockdown of ENO1, as well as PDIA3, in primary ATII cells led to reduced T1α expression, indicating diminished cell trans-differentiation. Our data thus identified proteins involved in ATII-to-ATI cell trans-differentiation and suggest a Wnt/β-catenin-driven functional role of ENO1 and PDIA3 in alveolar epithelial cell plasticity in lung injury and repair.

  9. Wnt secretion and signaling in Caenorhabditis elegans

    NARCIS (Netherlands)

    Yang, P.T.

    2008-01-01

    Wnt proteins are a highly conserved family of signaling molecules that play a central role during development and in adult tissue homeostasis. Wnt proteins regulate a variety of biological processes, ranging from cell proliferation and cell fate determination to cell migration, axon guidance and

  10. Amphioxus Sp5 is a member of a conserved Specificity Protein complement and is modulated by Wnt/beta-catenin signalling

    Czech Academy of Sciences Publication Activity Database

    Dailey, S.C.; Kozmiková, Iryna; Somorjai, I.M.L.

    2017-01-01

    Roč. 61, č. 10-12 (2017), s. 723-732 ISSN 0214-6282 R&D Projects: GA ČR GC15-21285J Institutional support: RVO:68378050 Keywords : Specificity protein * Brachyury * Branchiostoma * Wnt * Sp5 Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology Impact factor: 1.981, year: 2016

  11. Gut Commensal Bacteria and Regional Wnt Gene Expression in the Proximal Versus Distal Colon

    Science.gov (United States)

    Neumann, Philipp-Alexander; Koch, Stefan; Hilgarth, Roland S.; Perez-Chanona, Ernesto; Denning, Patricia; Jobin, Christian; Nusrat, Asma

    2015-01-01

    Regional expression of Wingless/Int (Wnt) genes plays a central role in regulating intestinal development and homeostasis. However, our knowledge of such regional Wnt proteins in the colon remains limited. To understand further the effect of Wnt signaling components in controlling intestinal epithelial homeostasis, we investigated whether the physiological heterogeneity of the proximal and distal colon can be explained by differential Wnt signaling. With the use of a Wnt signaling-specific PCR array, expression of 84 Wnt-mediated signal transduction genes was analyzed, and a differential signature of Wnt-related genes in the proximal versus distal murine colon was identified. Several Wnt agonists (Wnt5a, Wnt8b, and Wnt11), the Wnt receptor frizzled family receptor 3, and the Wnt inhibitory factor 1 were differentially expressed along the colon length. These Wnt signatures were associated with differential epithelial cell proliferation and migration in the proximal versus distal colon. Furthermore, reduced Wnt/β-catenin activity and decreased Wnt5a and Wnt11 expression were observed in mice lacking commensal bacteria, an effect that was reversed by conventionalization of germ-free mice. Interestingly, myeloid differentiation primary response gene 88 knockout mice showed decreased Wnt5a levels, indicating a role for Toll-like receptor signaling in regulating Wnt5a expression. Our results suggest that the morphological and physiological heterogeneity within the colon is in part facilitated by the differential expression of Wnt signaling components and influenced by colonization with bacteria. PMID:24418259

  12. Wnt3a nanodisks promote ex vivo expansion of hematopoietic stem and progenitor cells

    DEFF Research Database (Denmark)

    Lalefar, Nahal R.; Witkowski, Andrzej; Simonsen, Jens Bæk

    2016-01-01

    Background : Wnt proteins modulate development, stem cell fate and cancer through interactions with cell surface receptors. Wnts are cysteine-rich, glycosylated, lipid modified, two domain proteins that are prone to aggregation. The culprit responsible for this behavior is a covalently bound palm...... to Lin- Sca-1+ c-Kit+ cell expansion, an effect that was not mediated through β-catenin. Conclusions : The data indicate Wnt3a ND constitute a water-soluble transport vehicle capable of promoting ex vivo expansion of HSPC.......Background : Wnt proteins modulate development, stem cell fate and cancer through interactions with cell surface receptors. Wnts are cysteine-rich, glycosylated, lipid modified, two domain proteins that are prone to aggregation. The culprit responsible for this behavior is a covalently bound...... palmitoleoyl moiety in the N-terminal domain. Results : By combining murine Wnt3a with phospholipid and apolipoprotein A-I, ternary complexes termed nanodisks (ND) were generated. ND-associated Wnt3a is soluble in the absence of detergent micelles and gel filtration chromatography revealed that Wnt3a co...

  13. Caudal homeobox protein Cdx-2 cooperates with Wnt pathway to regulate claudin-1 expression in colon cancer cells.

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    Ajaz A Bhat

    Full Text Available Dysregulation of tight junctions (TJs is often associated with human diseases including carcinogenesis and recent studies support role of TJ integral proteins in the regulation of Epithelial-to-Mesenchymal Transition (EMT. In this regard, expression of claudin-1, a key constituent of TJs, is highly increased in colon cancer and is causally associated with the tumor growth and progression. However, mechanism/s underlying regulation of claudin-1 expression in intestinal epithelial cells remains poorly understood. In our studies, we have identified putative binding sites for intestinal transcription factors Cdx1, -2 and GATA4 in the 5'-flanking region of the claudin-1 gene. Our further studies using full length and/or deletion mutant constructs in two different human colon cancer cell lines, SW480 and HCT116, showed key role of Cdx1, Cdx2 and GATA4 in the regulation of claudin-1 mRNA expression. However, overexpression of Cdx2 had the most potent effect upon claudin-1 mRNA expression and promoter activity. Also, in colon cancer patient samples, we observed a significant and parallel correlation between claudin-1 and Cdx2 expressions. Chromatin immunoprecipitation (ChIP assay confirmed the Cdx2 binding with claudin-1 promoter in vivo. Using Cdx2 deletion mutant constructs, we further mapped the Cdx2 C-terminus domain to be important in the regulation of claudin-1 promoter activity. Interestingly, co-expression of activated β-catenin further induced the Cdx2-dependent upregulation of claudin-1 promoter activity while expression of the dominant negative (dn-TCF-4 abrogated this activation. Taken together, we conclude that homeodomain transcription factors Cdx1, Cdx2 and GATA4 regulate claudin-1 gene expression in human colon cancer cells. Moreover, a functional crosstalk between Wnt-signaling and transcriptional activation related to caudal-related homeobox (Cdx proteins and GATA-proteins is demonstrated in the regulation of claudin-1 promoter-activation.

  14. WNT-mediated Modulation of Bone Metabolism: Implications for WNT Targeting to Treat Extraskeletal Disorders.

    Science.gov (United States)

    Bullock, Whitney A; Robling, Alexander G

    2017-10-01

    The WNT-signaling pathway is involved in cellular and tissue functions that control such diverse processes as body axis patterning, cellular proliferation, differentiation, and life span. The long list of molecules that can participate or modify WNT signaling makes this pathway one of the most complex in cell biology. In bone tissues, WNT signaling is required for proper skeletal development, and human mutations in various components of the cascade revealed insights into pharmacologic targeting that can be harnessed to improve skeletal health. In particular, mutations in genes that code for the WNT-signaling inhibitor sclerostin or the WNT coreceptor lipoprotein receptor-related protein 5 have highlighted the potential therapeutic value of recapitulating those effects in patients with low bone mass. A constant challenge in this area is selectively modifying WNT components in the tissue of interest, as WNT has manifold effects in nearly every tissue.

  15. WNT signalling and haematopoiesis: a WNT-WNT situation.

    NARCIS (Netherlands)

    Staal, F.J.T.; Clevers, J.C.

    2005-01-01

    The evolutionarily conserved WNT-signalling pathway has pivotal roles during the development of many organ systems, and dysregulated WNT signalling is a key factor in the initiation of various tumours. Recent studies have implicated a role for WNT signal transduction at several stages of lymphocyte

  16. Arsenic trioxide increases expression of secreted frizzled-related protein 1 gene and inhibits the WNT/β-catenin signaling pathway in Jurkat cells.

    Science.gov (United States)

    Wang, Yan; Wang, Zunsong; Li, Hong; Xu, Wenwei; Dong, Lin; Guo, Yan; Feng, Saran; Bi, Kehong; Zhu, Chuansheng

    2017-05-01

    The aim of the present study was to investigate the demethylation effect of arsenic trioxide (As 2 O 3 ) on the secreted frizzled-related protein 1 (SFRP1) gene and its ability to inhibit the Wingless-type MMTV integration site family (WNT) pathway in Jurkat cells. Methylation-specific polymerase chain reaction was used to examine the CpG island methylation status of the SFRP1 gene in leukemia cell lines. In addition, the effects on Jurkat cells of treatment with different concentrations of As 2 O 3 for 48 h were investigated. Reverse transcription-quantitative polymerase chain reaction was employed to measure the expression of mRNAs, while western blot analysis was used to examine protein expression in cells. The SFRP1 gene was methylated in Jurkat cells. However, both methylated and unmethylated SFRP1 genes were detected in HL60 and K562 cells. In normal bone marrow mononuclear cells, the SFRP1 gene was unmethylated. Following treatment with As 2 O 3 for 48 h, the SFRP1 gene was demethylated, and the mRNA and protein expression levels of the SFRP1 gene were increased. By contrast, the mRNA and protein expression levels of β-catenin and cyclin Dl were downregulated. The protein expression of c-myc was also downregulated, but As 2 O 3 exhibited no significant effect on the mRNA expression of c-myc. Abnormal methylation of the SFRP1 gene was detected in Jurkat cells. These results suggest that As 2 O 3 activates SFRP1 gene expression at the mRNA and protein levels in Jurkat cells by demethylation of the SFRP1 gene. Furthermore, they indicate that As 2 O 3 regulates WNT target genes and controls the growth of Jurkat cells through the WNT/β-catenin signaling pathway.

  17. Wnt-inducible protein (WISP-1 is a key regulator of alveolar epithelial cell hyperplasia in pulmonary fibrosis

    Directory of Open Access Journals (Sweden)

    Melanie Königshoff

    2006-12-01

    Full Text Available Fibrotic lung disease is characterized by distorted lung architecture and severe loss of respiratory function secondary to alveolar epithelial cell (AEC hyperplasia, enhanced extracellular matrix (ECM deposition and fibroblast proliferation. Repetitive epithelial injuries with impaired alveolar wound healing and altered AEC gene expression represent a trigger mechanism for development of fibrosis. To reveal gene regulatory networks in lung fibrosis, we compared gene expression profiles of freshly isolated AEC obtained from mice 14 days after saline or bleomycin (BM instillation using whole genome microarray analysis. Several genes of the Wnt signaling pathway, in particular WISP-1, a member of the CCN family, were highly regulated. WISP-1 protein expression was demonstrated in proliferating AEC in BM-treated lungs by immunofluorescence. When analyzing all six CCN family members, WISP-1 was upregulated the most 14 days after BM challenge, as analyzed by qRT-PCR. To elucidate WISP-1 function, cultured primary mouse AEC were stimulated with WISP-1 and demonstrated a 230% increase in proliferation, analyzed by 3H-thymidine incorporation. This was mediated through enhanced phosphorylation, but not expression of protein kinase B (PKB/Akt, as detected by immunoblot. Finally, increased expression of WISP-1 was detected in lung homogenates and isolated AEC from IPF patients, using qRT-PCR. Immunohistochemical analysis of WISP-1 and Ki67 verified the existence of hyperplastic and proliferative AEC expressing WISP-1 in vivo. Our study thus identifies WISP-1 as a novel regulator of AEC injury and repair, and suggests that WISP-1 is a key mediator in pulmonary fibrosis.

  18. The key role of proinflammatory cytokines, matrix proteins, RANKL/OPG and Wnt/β-catenin in bone healing of hip arthroplasty patients.

    Science.gov (United States)

    Cassuto, Jean; Folestad, Agnetha; Göthlin, Jan; Malchau, Henrik; Kärrholm, Johan

    2018-02-01

    We still lack understanding of why some implants fail while most remain stable after decades of use. Proinflammatory cytokines, matrix proteins and bone regulating cytokines of the RANKL/OPG (receptor activator of nuclear factor kappa B ligand/osteoprotegerin) and Wnt/β-catenin pathways are mandatory for normal bone repair but their spatial and temporal role in the healing of primary total hip arthroplasties (THA) has not been previously shown. Twenty-four osteoarthritis patients with one-sided well-fixed primary THA were prospectively monitored during 18years (18Y) with repeated blood samples, clinical variables and radiographs. Eighty-one healthy donors divided in three age- and gender-matched groups and twenty osteoarthritis patients awaiting THA and serving as control of the validity of stored plasma in THA patients, were included. Plasma was analyzed for C-reactive protein (CRP), interleukin (IL)-6, IL-8, IL-1β, tumor necrosis factor (TNF)-α, osteopontin (OPN), secreted protein acidic and rich in cysteine (SPARC/osteonectin), osteocalcin (OC), bone specific alkaline phosphatase (BALP), N-terminal propeptide of collagen type I (P1NP), RANKL, OPG, the Wnt agonistic ligands (Wnt)-1 and Wnt-3a, and the Wnt antagonists sclerostin, Dickkopf (Dkk)-1, Dkk-3, Dkk-4, secreted frizzled related protein (sFRP)-1, sFRP-3 and Wnt inhibitory factor-1 (Wif-1). Inflammatory mediators in arthroplasty patients (CRP, IL-6, OPN) increased significantly on day one after surgery vs preoperative value (PR) and healthy subjects and returned to baseline at 6W. TNF-α did not change relative preoperative level or healthy subjects. SPARC and OC increased in a biphasic fashion with the primary phase beginning shortly after surgery and lasting 3M (SPARC) and 2Y (OC) while the secondary phase peaked at 1Y (SPARC) and 13Y (OC), with both returning to basal level at 15Y. BALP peaked at 3M after surgery with a return to basal level at 2Y followed by a continuous increase from 5Y until 18Y. P

  19. Sailing with the Wnt: charting the Wnt processing and secretion route

    NARCIS (Netherlands)

    Lorenowicz, M.J.; Korswagen, H.C.

    2009-01-01

    Wnt proteins are members of a highly conserved family of signalling molecules that play a central role in development and disease. During the past years, the different signalling pathways that are triggered by Wnt proteins have been studied in detail, but it is still largely unknown how a functional

  20. Wnt signaling and polarity in freshwater sponges.

    Science.gov (United States)

    Windsor Reid, Pamela J; Matveev, Eugueni; McClymont, Alexandra; Posfai, Dora; Hill, April L; Leys, Sally P

    2018-02-02

    The Wnt signaling pathway is uniquely metazoan and used in many processes during development, including the formation of polarity and body axes. In sponges, one of the earliest diverging animal groups, Wnt pathway genes have diverse expression patterns in different groups including along the anterior-posterior axis of two sponge larvae, and in the osculum and ostia of others. We studied the function of Wnt signaling and body polarity formation through expression, knockdown, and larval manipulation in several freshwater sponge species. Sponge Wnts fall into sponge-specific and sponge-class specific subfamilies of Wnt proteins. Notably Wnt genes were not found in transcriptomes of the glass sponge Aphrocallistes vastus. Wnt and its signaling genes were expressed in archaeocytes of the mesohyl throughout developing freshwater sponges. Osculum formation was enhanced by GSK3 knockdown, and Wnt antagonists inhibited both osculum development and regeneration. Using dye tracking we found that the posterior poles of freshwater sponge larvae give rise to tissue that will form the osculum following metamorphosis. Together the data indicate that while components of canonical Wnt signaling may be used in development and maintenance of osculum tissue, it is likely that Wnt signaling itself occurs between individual cells rather than whole tissues or structures in freshwater sponges.

  1. Chemical Modulation of WNT Signaling in Cancer.

    Science.gov (United States)

    Zhang, Li-Shu; Lum, Lawrence

    2018-01-01

    Genetically based observations stemming from defects in development and in regeneration form the foundation of our understanding regarding how the secreted WNT proteins control coordinated cell fate decision-making in adult tissues. At the same time, our anticipation of potential benefits and unwanted toxicities associated with candidate anticancer agents targeting WNT signal transduction are also reliant upon this blueprint of WNT-associated physiology. Despite the long established role of WNT signaling in cancer, the emergence of WNT signaling as a suppressor of immunological attack in melanoma reveals an unanticipated anticancer potential in targeting WNT signaling. Here we review the literature associated with WNT signaling in cancer and discuss potential challenges that may be associated with the chemical attack of this important cellular process in achieving therapeutic goals. Although a number of small molecules targeting WNT signaling are introduced here, we center our discussion on antagonists of the WNT acyltransferase porcupine (PORCN) given the recent entry of two candidate molecules in clinical testing. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. A Wnt Survival Guide: From Flies to Human Disease

    Science.gov (United States)

    Chien, Andy J.; Conrad, William H.; Moon, Randall T.

    2011-01-01

    It has been two decades since investigators discovered the link between the Drosophila wingless (Wg) gene and the vertebrate oncogene int-1, thus establishing the family of signaling proteins known as Wnts. Since the inception of the Wnt signaling field, there have been 19 Wnt isoforms identified in humans. These secreted glycoproteins can activate at least two distinct signaling pathways in vertebrate cells, leading to cellular changes that regulate a vast array of biological processes, including embryonic development, cell fate, cell proliferation, cell migration, stem cell maintenance, tumor suppression, and oncogenesis. In certain contexts, one subset of Wnt isoforms activates the canonical Wnt/β-catenin pathway that is characterized by the activation of certain β-catenin-responsive target genes in response to the binding of Wnt ligand to its cognate receptors. Similarly, a second subset of Wnt isoforms activates β-catenin-independent pathways, including the Wnt/ calcium (Wnt/Ca) pathway and the Wnt/planar cell polarity (Wnt/PCP) pathway, in certain cellular contexts. In addition, research has identified several secreted proteins known to regulate Wnt signaling, including the Dickkopf (DKK) family, secreted Frizzled-related proteins (sFRPs), and Wnt inhibitory factor-1 (WIF-1). The advent of technologies that can provide genome-wide expression data continues to implicate Wnts and proteins that regulate Wnt signaling pathways in a growing number of disease processes. The aim of this review is to provide a context on the Wnt field that will facilitate the interpretation and study of Wnt signaling in the context of human disease. PMID:19177135

  3. Effect of aspirin on the Wnt/beta-catenin pathway is mediated via protein phosphatase 2A

    NARCIS (Netherlands)

    Bos, C. L.; Kodach, L. L.; van den Brink, G. R.; Diks, S. H.; van Santen, M. M.; Richel, D. J.; Peppelenbosch, M. P.; Hardwick, J. C. H.

    2006-01-01

    Nonsteroidal anti-inflammatory drugs show chemopreventive efficacy in colon cancer, but the mechanism behind this remains unclear. Elucidating this mechanism is seen as vital to the development of new chemopreventive agents. We studied the effects of aspirin on the oncogenic Wnt/beta-catenin pathway

  4. WNT5A encodes two isoforms with distinct functions in cancers.

    Directory of Open Access Journals (Sweden)

    Matthieu Bauer

    Full Text Available WNT5A, a member of the WNT family of secreted lipid-modified glycoproteins, is a critical regulator of a host of developmental processes, including limb formation, lung morphogenesis, intestinal elongation and mammary gland development. Altered WNT5A expression has been associated with a number of cancers. Interestingly, in certain types of cancers, such as hematological malignancies and colorectal carcinoma, WNT5A is inactivated and exerts a tumor suppressive function, while in other cancers, such as melanoma and gastric carcinoma, WNT5A is overexpressed and promotes tumor progression. The mechanism by which WNT5A achieves these distinct activities in cancers is poorly understood. Here, we provide evidence that the WNT5A gene produces two protein isoforms, WNT5A-long (WNT5A-L and WNT5A-short (WNT5A-S. Amino-terminal sequencing and a WNT5A-L specific antibody demonstrate that the mature and secreted isoforms are distinct, with WNT5A-L carrying an additional 18 N-terminal amino acids. Biochemical analysis indicates that both purified proteins are similar with respect to their stability, hydrophobicity and WNT/β-catenin signaling activity. Nonetheless, modulation of these two WNT5A isoforms, either through ectopic expression or knockdown, demonstrates that they exert distinct activities in cancer cell lines: while WNT5A-L inhibits proliferation of tumor cell lines, WNT5A-S promotes their growth. Finally, we show that expression of these two WNT5A isoforms is altered in breast and cervix carcinomas, as well as in the most aggressive neuroblastoma tumors. In these cancers, WNT5A-L is frequently down-regulated, whereas WNT5A-S is found overexpressed in a significant fraction of tumors. Altogether, our study provides evidence that the distinct activities of WNT5A in cancer can be attributed to the production of two WNT5A isoforms.

  5. IQ-domain GTPase-activating protein 1 promotes the malignant phenotype of invasive ductal breast carcinoma via canonical Wnt pathway.

    Science.gov (United States)

    Zhao, Huan-Yu; Han, Yang; Wang, Jian; Yang, Lian-He; Zheng, Xiao-Ying; Du, Jiang; Wu, Guang-Ping; Wang, En-Hua

    2017-06-01

    IQ-domain GTPase-activating protein 1 is a scaffolding protein with multidomain which plays a role in modulating dishevelled (Dvl) nuclear translocation in canonical Wnt pathway. However, the biological function and mechanism of IQ-domain GTPase-activating protein 1 in invasive ductal carcinoma (IDC) remain unknown. In this study, we found that IQ-domain GTPase-activating protein 1 expression was elevated in invasive ductal carcinoma, which was positively correlated with tumor grade, lymphatic metastasis, and poor prognosis. Coexpression of IQ-domain GTPase-activating protein 1 and Dvl in the nucleus and cytoplasm of invasive ductal carcinoma was significantly correlated but not in the membrane. Postoperative survival in the patients with their coexpression in the nucleus and cytoplasm was obviously lower than that without coexpression. The positive expression rates of c-myc and cyclin D1 were significantly higher in the patients with nuclear coexpression of Dvl and IQ-domain GTPase-activating protein 1 than that with cytoplasmic coexpression, correlating with poor prognosis. IQ-domain GTPase-activating protein 1 significantly enhanced cell proliferation and invasion in invasive ductal carcinoma cell lines by interacting with Dvl in cytoplasm to promote Dvl nuclear translocation so as to upregulate the expression of c-myc and cyclin D1. Collectively, our data suggest that IQ-domain GTPase-activating protein 1 may promote the malignant phenotype of invasive ductal carcinoma via canonical Wnt signaling, and it could be used as a potential prognostic biomarker for breast cancer patients.

  6. TMEM59 potentiates Wnt signaling by promoting signalosome formation.

    Science.gov (United States)

    Gerlach, Jan P; Jordens, Ingrid; Tauriello, Daniele V F; van 't Land-Kuper, Ineke; Bugter, Jeroen M; Noordstra, Ivar; van der Kooij, Johanneke; Low, Teck Y; Pimentel-Muiños, Felipe X; Xanthakis, Despina; Fenderico, Nicola; Rabouille, Catherine; Heck, Albert J R; Egan, David A; Maurice, Madelon M

    2018-04-09

    Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt-FZD assemblies via intramembrane interactions. Subsequently, these Wnt-FZD-TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions. Copyright © 2018 the Author(s). Published by PNAS.

  7. International Union of Basic and Clinical Pharmacology Review: WNT/Frizzled signalling: receptor–ligand selectivity with focus on FZD-G protein signalling and its physiological relevance: IUPHAR Review 3

    Science.gov (United States)

    Dijksterhuis, J P; Petersen, J; Schulte, G

    2014-01-01

    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/Ca2+. 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. LINKED ARTICLESThis article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-5 PMID:24032637

  8. Surrogate Wnt agonists that phenocopy canonical Wnt and β-catenin signalling

    NARCIS (Netherlands)

    Janda, Claudia Y.; Dang, Luke T.; You, Changjiang; Chang, Junlei; Lau, Wim De; Zhong, Zhendong A.; Yan, Kelley S.; Marecic, Owen; Siepe, DIrk; Li, Xingnan; Moody, James D.; Williams, Bart O.; Clevers, Hans; Piehler, Jacob; Baker, David; Kuo, Calvin J.; Garcia, K. Christopher

    2017-01-01

    Wnt proteins modulate cell proliferation and differentiation and the self-renewal of stem cells by inducing β-catenin-dependent signalling through the Wnt receptor frizzled (FZD) and the co-receptors LRP5 and LRP6 to regulate cell fate decisions and the growth and repair of several tissues. The 19

  9. Regulation of Wnt/β-catenin signaling by posttranslational modifications

    Science.gov (United States)

    2014-01-01

    The canonical Wnt signaling pathway (or Wnt/β-catenin pathway) plays a pivotal role in embryonic development and adult homeostasis; deregulation of the Wnt pathway contributes to the initiation and progression of human diseases including cancer. Despite its importance in human biology and disease, how regulation of the Wnt/β-catenin pathway is achieved remains largely undefined. Increasing evidence suggests that post-translational modifications (PTMs) of Wnt pathway components are essential for the activation of the Wnt/β-catenin pathway. PTMs create a highly dynamic relay system that responds to Wnt stimulation without requiring de novo protein synthesis and offer a platform for non-Wnt pathway components to be involved in the regulation of Wnt signaling, hence providing alternative opportunities for targeting the Wnt pathway. This review highlights the current status of PTM-mediated regulation of the Wnt/β-catenin pathway with a focus on factors involved in Wnt-mediated stabilization of β-catenin. PMID:24594309

  10. Wnt signaling in ankylosing spondylitis.

    Science.gov (United States)

    Corr, Maripat

    2014-06-01

    The mechanisms that lead to bony fusion in ankylosing spondylitis (AS) are yet to be fully defined. In recent years, there have been several advances in our understanding of this complex disease. Here, the potential impact of the Wnt signaling pathway will be discussed. This pathway is involved in bone morphogenesis and homeostasis. Perturbations in the normal regulation have been implicated in abnormal bone formation (e.g., osteophytes). Levels of Wnt regulatory proteins like Dickkopf have been investigated as potential biomarkers of disease. This pathway might be involved in other aspects of this disease including T cell activation and differentiation, and in bone marrow adipogenesis. The pathways leading to the unique pathology and bony fusion in AS are complex and the Wnt pathway might play a critical contributing role.

  11. The Wnt Signaling Pathway Is Differentially Expressed during the Bovine Herpesvirus 1 Latency-Reactivation Cycle: Evidence That Two Protein Kinases Associated with Neuronal Survival, Akt3 and BMPR2, Are Expressed at Higher Levels during Latency.

    Science.gov (United States)

    Workman, Aspen; Zhu, Liqian; Keel, Brittney N; Smith, Timothy P L; Jones, Clinton

    2018-04-01

    Sensory neurons in trigeminal ganglia (TG) of calves latently infected with bovine herpesvirus 1 (BoHV-1) abundantly express latency-related (LR) gene products, including a protein (ORF2) and two micro-RNAs. Recent studies in mouse neuroblastoma cells (Neuro-2A) demonstrated ORF2 interacts with β-catenin and a β-catenin coactivator, high-mobility group AT-hook 1 (HMGA1) protein, which correlates with increased β-catenin-dependent transcription and cell survival. β-Catenin and HMGA1 are readily detected in a subset of latently infected TG neurons but not TG neurons from uninfected calves or reactivation from latency. Consequently, we hypothesized that the Wnt/β-catenin signaling pathway is differentially expressed during the latency and reactivation cycle and an active Wnt pathway promotes latency. RNA-sequencing studies revealed that 102 genes associated with the Wnt/β-catenin signaling pathway were differentially expressed in TG during the latency-reactivation cycle in calves. Wnt agonists were generally expressed at higher levels during latency, but these levels decreased during dexamethasone-induced reactivation. The Wnt agonist bone morphogenetic protein receptor 2 (BMPR2) was intriguing because it encodes a serine/threonine receptor kinase that promotes neuronal differentiation and inhibits cell death. Another differentially expressed gene encodes a protein kinase (Akt3), which is significant because Akt activity enhances cell survival and is linked to herpes simplex virus 1 latency and neuronal survival. Additional studies demonstrated ORF2 increased Akt3 steady-state protein levels and interacted with Akt3 in transfected Neuro-2A cells, which correlated with Akt3 activation. Conversely, expression of Wnt antagonists increased during reactivation from latency. Collectively, these studies suggest Wnt signaling cooperates with LR gene products, in particular ORF2, to promote latency. IMPORTANCE Lifelong BoHV-1 latency primarily occurs in sensory neurons

  12. Murrayafoline A attenuates the Wnt/{beta}-catenin pathway by promoting the degradation of intracellular {beta}-catenin proteins

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyuk; Gwak, Jungsug; Cho, Munju; Ryu, Min-Jung [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Lee, Jee-Hyun; Kim, Sang Kyum; Kim, Young Ho [College of Pharmacy, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Gye Won [Department of Pharmaceutical Engineering, Konyang University, Nonsan 320-711 (Korea, Republic of); Yun, Mi-Young [Department of Beauty Health Care, Daejeon University, Daejeon 305-764 (Korea, Republic of); Cuong, Nguyen Manh [Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Shin, Jae-Gook [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Song, Gyu-Yong, E-mail: gysong@cnu.ac.kr [College of Pharmacy, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Oh, Sangtaek, E-mail: ohsa@inje.ac.kr [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of)

    2010-01-01

    Molecular lesions in Wnt/{beta}-catenin signaling and subsequent up-regulation of {beta}-catenin response transcription (CRT) occur frequently during the development of colon cancer. To identify small molecules that suppress CRT, we screened natural compounds in a cell-based assay for detection of TOPFalsh reporter activity. Murrayafoline A, a carbazole alkaloid isolated from Glycosmis stenocarpa, antagonized CRT that was stimulated by Wnt3a-conditioned medium (Wnt3a-CM) or LiCl, an inhibitor of glycogen synthase kinase-3{beta} (GSK-3{beta}), and promoted the degradation of intracellular {beta}-catenin without altering its N-terminal phosphorylation at the Ser33/37 residues, marking it for proteasomal degradation, or the expression of Siah-1, an E3 ubiquitin ligase. Murrayafoline A repressed the expression of cyclin D1 and c-myc, which is known {beta}-catenin/T cell factor (TCF)-dependent genes and thus inhibited the proliferation of various colon cancer cells. These findings indicate that murrayafoline A may be a potential chemotherapeutic agent for use in the treatment of colon cancer.

  13. Murrayafoline A attenuates the Wnt/β-catenin pathway by promoting the degradation of intracellular β-catenin proteins

    International Nuclear Information System (INIS)

    Choi, Hyuk; Gwak, Jungsug; Cho, Munju; Ryu, Min-Jung; Lee, Jee-Hyun; Kim, Sang Kyum; Kim, Young Ho; Lee, Gye Won; Yun, Mi-Young; Cuong, Nguyen Manh; Shin, Jae-Gook; Song, Gyu-Yong; Oh, Sangtaek

    2010-01-01

    Molecular lesions in Wnt/β-catenin signaling and subsequent up-regulation of β-catenin response transcription (CRT) occur frequently during the development of colon cancer. To identify small molecules that suppress CRT, we screened natural compounds in a cell-based assay for detection of TOPFalsh reporter activity. Murrayafoline A, a carbazole alkaloid isolated from Glycosmis stenocarpa, antagonized CRT that was stimulated by Wnt3a-conditioned medium (Wnt3a-CM) or LiCl, an inhibitor of glycogen synthase kinase-3β (GSK-3β), and promoted the degradation of intracellular β-catenin without altering its N-terminal phosphorylation at the Ser33/37 residues, marking it for proteasomal degradation, or the expression of Siah-1, an E3 ubiquitin ligase. Murrayafoline A repressed the expression of cyclin D1 and c-myc, which is known β-catenin/T cell factor (TCF)-dependent genes and thus inhibited the proliferation of various colon cancer cells. These findings indicate that murrayafoline A may be a potential chemotherapeutic agent for use in the treatment of colon cancer.

  14. Effect of Wnt3a on Keratinocytes Utilizing in Vitro and Bioinformatics Analysis

    Directory of Open Access Journals (Sweden)

    Ju-Suk Nam

    2014-03-01

    Full Text Available Wingless-type (Wnt signaling proteins participate in various cell developmental processes. A suppressive role of Wnt5a on keratinocyte growth has already been observed. However, the role of other Wnt proteins in proliferation and differentiation of keratinocytes remains unknown. Here, we investigated the effects of the Wnt ligand, Wnt3a, on proliferation and differentiation of keratinocytes. Keratinocytes from normal human skin were cultured and treated with recombinant Wnt3a alone or in combination with the inflammatory cytokine, tumor necrosis factor α (TNFα. Furthermore, using bioinformatics, we analyzed the biochemical parameters, molecular evolution, and protein–protein interaction network for the Wnt family. Application of recombinant Wnt3a showed an anti-proliferative effect on keratinocytes in a dose-dependent manner. After treatment with TNFα, Wnt3a still demonstrated an anti-proliferative effect on human keratinocytes. Exogenous treatment of Wnt3a was unable to alter mRNA expression of differentiation markers of keratinocytes, whereas an altered expression was observed in TNFα-stimulated keratinocytes. In silico phylogenetic, biochemical, and protein–protein interaction analysis showed several close relationships among the family members of the Wnt family. Moreover, a close phylogenetic and biochemical similarity was observed between Wnt3a and Wnt5a. Finally, we proposed a hypothetical mechanism to illustrate how the Wnt3a protein may inhibit the process of proliferation in keratinocytes, which would be useful for future researchers.

  15. A1330V variant of the low-density lipoprotein receptor-related protein 5 (LRP5) gene decreases Wnt signaling and affects the total body bone mineral density in Japanese women.

    Science.gov (United States)

    Urano, Tomohiko; Shiraki, Masataka; Usui, Takahiko; Sasaki, Noriko; Ouchi, Yasuyoshi; Inoue, Satoshi

    2009-01-01

    Wnt signaling is an important regulator of bone homeostasis. The Wnt co-receptor, namely, low-density lipoprotein receptor-related protein 5 (LRP5), initiates Wnt signal transduction. Recently, we and several other groups have shown that there is a single nucleotide polymorphism (SNP) located in the exon 18 of the LRP5 gene that leads to an amino acid change (3989C > T, A1330V), and is associated with lumbar spine, femoral neck, and radial bone mineral density (BMD), and incidence of fracture. These data suggest that the A1330V variation in the LRP5 gene may affect the pathogenesis of osteoporosis. However, the functional basis of the A1330V variation remains unclear. In the present study, we analyzed the effect of the A1330V variation on Wnt activity. We also investigated the association between this LRP5 SNP and total body BMD using 739 postmenopausal women. LRP5 with the A1330V SNP were transiently coexpressed with Wnt3a in 293T cells and their activity was evaluated by the TCF-Lef reporter assay. In vitro, the TCF-Lef activity in presence of Wnt3a in cells expressing LRP5 and carrying the T allele (Valine at 1330 (V1330)) of exon 18 was significantly reduced as compared to the wild-type allele. The association between the A1330V SNP and total body BMD were replicated in 739 postmenopausal Japanese women (AA vs. VV; P = 0.0026). These data suggest that the V1330 variant in the LRP5 gene decreases Wnt activity, which in turn decreases the BMD.

  16. A Wnt oscillator model for somitogenesis

    DEFF Research Database (Denmark)

    Jensen, Peter Bjødstrup; Pedersen, Lykke; Krishna, Sandeep

    2010-01-01

    We propose a model for the segmentation clock in vertebrate somitogenesis, based on the Wnt signaling pathway. The core of the model is a negative feedback loop centered around the Axin2 protein. Axin2 is activated by beta-catenin, which in turn is degraded by a complex of GSK3beta and Axin2...... for the oscillations is the saturated degradation of Axin2. Somite formation in chick and mouse embryos is controlled by a spatial Wnt gradient which we introduce in the model through a time-dependent decrease in Wnt3a ligand level. We find that the oscillations disappear as the ligand concentration decreases...

  17. Next-Generation Sequencing for Binary Protein-Protein Interactions

    Directory of Open Access Journals (Sweden)

    Bernhard eSuter

    2015-12-01

    Full Text Available The yeast two-hybrid (Y2H system exploits host cell genetics in order to display binary protein-protein interactions (PPIs via defined and selectable phenotypes. Numerous improvements have been made to this method, adapting the screening principle for diverse applications, including drug discovery and the scale-up for proteome wide interaction screens in human and other organisms. Here we discuss a systematic workflow and analysis scheme for screening data generated by Y2H and related assays that includes high-throughput selection procedures, readout of comprehensive results via next-generation sequencing (NGS, and the interpretation of interaction data via quantitative statistics. The novel assays and tools will serve the broader scientific community to harness the power of NGS technology to address PPI networks in health and disease. We discuss examples of how this next-generation platform can be applied to address specific questions in diverse fields of biology and medicine.

  18. Next-Generation Sequencing for Binary Protein-Protein Interactions.

    Science.gov (United States)

    Suter, Bernhard; Zhang, Xinmin; Pesce, C Gustavo; Mendelsohn, Andrew R; Dinesh-Kumar, Savithramma P; Mao, Jian-Hua

    2015-01-01

    The yeast two-hybrid (Y2H) system exploits host cell genetics in order to display binary protein-protein interactions (PPIs) via defined and selectable phenotypes. Numerous improvements have been made to this method, adapting the screening principle for diverse applications, including drug discovery and the scale-up for proteome wide interaction screens in human and other organisms. Here we discuss a systematic workflow and analysis scheme for screening data generated by Y2H and related assays that includes high-throughput selection procedures, readout of comprehensive results via next-generation sequencing (NGS), and the interpretation of interaction data via quantitative statistics. The novel assays and tools will serve the broader scientific community to harness the power of NGS technology to address PPI networks in health and disease. We discuss examples of how this next-generation platform can be applied to address specific questions in diverse fields of biology and medicine.

  19. Wnt signaling in cancer

    Science.gov (United States)

    Zhan, T; Rindtorff, N; Boutros, M

    2017-01-01

    Wnt signaling is one of the key cascades regulating development and stemness, and has also been tightly associated with cancer. The role of Wnt signaling in carcinogenesis has most prominently been described for colorectal cancer, but aberrant Wnt signaling is observed in many more cancer entities. Here, we review current insights into novel components of Wnt pathways and describe their impact on cancer development. Furthermore, we highlight expanding functions of Wnt signaling for both solid and liquid tumors. We also describe current findings how Wnt signaling affects maintenance of cancer stem cells, metastasis and immune control. Finally, we provide an overview of current strategies to antagonize Wnt signaling in cancer and challenges that are associated with such approaches. PMID:27617575

  20. 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.

  1. Regulation of Wnt signaling by nociceptive input in animal models

    Directory of Open Access Journals (Sweden)

    Shi Yuqiang

    2012-06-01

    Full Text Available Abstract Background Central sensitization-associated synaptic plasticity in the spinal cord dorsal horn (SCDH critically contributes to the development of chronic pain, but understanding of the underlying molecular pathways is still incomplete. Emerging evidence suggests that Wnt signaling plays a crucial role in regulation of synaptic plasticity. Little is known about the potential function of the Wnt signaling cascades in chronic pain development. Results Fluorescent immunostaining results indicate that β-catenin, an essential protein in the canonical Wnt signaling pathway, is expressed in the superficial layers of the mouse SCDH with enrichment at synapses in lamina II. In addition, Wnt3a, a prototypic Wnt ligand that activates the canonical pathway, is also enriched in the superficial layers. Immunoblotting analysis indicates that both Wnt3a a β-catenin are up-regulated in the SCDH of various mouse pain models created by hind-paw injection of capsaicin, intrathecal (i.t. injection of HIV-gp120 protein or spinal nerve ligation (SNL. Furthermore, Wnt5a, a prototypic Wnt ligand for non-canonical pathways, and its receptor Ror2 are also up-regulated in the SCDH of these models. Conclusion Our results suggest that Wnt signaling pathways are regulated by nociceptive input. The activation of Wnt signaling may regulate the expression of spinal central sensitization during the development of acute and chronic pain.

  2. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Dickkopf-Related Protein 2 is Epigenetically Inactivated and Suppresses Colorectal Cancer Growth and Tumor Metastasis by Antagonizing Wnt/β-Catenin Signaling

    Directory of Open Access Journals (Sweden)

    Can Wang

    2017-03-01

    Full Text Available Background/Aims: Aberrant activation of the Wnt/β-catenin signaling pathway plays a key role in the pathogenesis of multiple tumors including digestive cancers. Recent studies have reported that Dickkopf-related protein 2 (DKK2 is epigenetically inactivated in numerous types of cancers and that its gene products exhibit tumor-suppressive properties. However, the biological functions and underlying molecular mechanisms of DKK2 in colon carcinoma remains obscure. Methods: We examined the expression of DKK2 in colon tumor cell lines by RT-PCR and its promoter methylation status in colon tumor cell lines and primary tumors by methylation-specific PCR (MSP. Ectopic expression of DKK2 was measured by RT-PCR prior to the other experiments. To investigate the function of DKK2, we assayed colony formation and cell proliferation, utilized flow cytometric analyses of the cell cycle and acridine orange/ethidium bromide (AO/EB fluorescence staining for apoptosis, and examined wound healing, transwell migration and tumor growth in vivo. Western blots were used to explore the mechanisms of DKK2 in epithelial- mesenchymal transition and canonical Wnt/β-catenin signaling. Results: We show here that downregulation or silencing of DKK2 was closely associated with the hypermethylation status of its promoter and that DKK2 expression could be restored by demethylation treatment. Methylation of the DKK2 promoter was detected in nearly all tumors and tumor-adjacent tissues, but not in normal colon tissues. Ectopic expression of DKK2 in colon cell lines HCT116 and HT-29 inhibited colony formation and cell viability by inducing cell cycle G0/G1 arrest and apoptosis, and growth of stable DKK2-infected HCT116 cells in nude mice was decreased compared to controls. Furthermore, DKK2 restrained cell migration through partial reversal of epithelial-to- mesenchymal transition and also by downregulating several stem cell markers. Our data further showed that restoration of DKK

  4. Human I-mfa domain proteins specifically interact with KSHV LANA and affect its regulation of Wnt signaling-dependent transcription

    Energy Technology Data Exchange (ETDEWEB)

    Kusano, Shuichi, E-mail: skusano@m2.kufm.kagoshima-u.ac.jp [Division of Persistent and Oncogenic Viruses, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544 (Japan); Eizuru, Yoshito [Division of Persistent and Oncogenic Viruses, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544 (Japan)

    2010-06-04

    Kaposi's sarcoma-associated herpes virus (KSHV)-encoded latency-associated nuclear antigen (LANA) protein has been reported to interact with glycogen synthase kinase 3{beta} (GSK-3{beta}) and to negatively regulate its activity, leading to stimulation of GSK-3{beta}-dependent {beta}-catenin degradation. We show here that the I-mfa domain proteins, HIC (human I-mfa domain-containing protein) and I-mfa (inhibitor of MyoD family a), interacted in vivo with LANA through their C-terminal I-mfa domains. This interaction affected the intracellular localization of HIC, inhibited the LANA-dependent transactivation of a {beta}-catenin-regulated reporter construct, and decreased the level of the LANA.GSK-3{beta} complex. These data reveal for the first time that I-mfa domain proteins interact with LANA and negatively regulate LANA-mediated activation of Wnt signaling-dependent transcription by inhibiting the formation of the LANA.GSK-3{beta} complex.

  5. Interplay between a Wnt-dependent organiser and the Notch segmentation clock regulates posterior development in Periplaneta americana

    Directory of Open Access Journals (Sweden)

    John E. Chesebro

    2012-12-01

    Sequential addition of segments in the posteriorly growing end of the embryo is a developmental mechanism common to many bilaterians. However, posterior growth and patterning in most animals also entails the establishment of a ‘posterior organiser’ that expresses the Caudal and Wnt proteins and has been proposed to be an ancestral feature of animal development. We have studied the functional relationships between the Wnt-driven organiser and the segmentation mechanisms in a basal insect, the cockroach Periplaneta americana. Here, posteriorly-expressed Wnt1 promotes caudal and Delta expression early in development to generate a growth zone from which segments will later bud off. caudal maintains the undifferentiated growth zone by dampening Delta expression, and hence Notch-mediated segmentation occurs just outside the caudal domain. In turn, Delta expression maintains Wnt1, maintaining this posterior gene network until all segments have formed. This feedback between caudal, Wnt and Notch-signalling in regulating growth and segmentation seems conserved in other arthropods, with some aspects found even in vertebrates. Thus our findings not only support an ancestral Wnt posterior organiser, but also impinge on the proposals for a common origin of segmentation in arthropods, annelids and vertebrates.

  6. Learning generative models for protein fold families.

    Science.gov (United States)

    Balakrishnan, Sivaraman; Kamisetty, Hetunandan; Carbonell, Jaime G; Lee, Su-In; Langmead, Christopher James

    2011-04-01

    We introduce a new approach to learning statistical models from multiple sequence alignments (MSA) of proteins. Our method, called GREMLIN (Generative REgularized ModeLs of proteINs), learns an undirected probabilistic graphical model of the amino acid composition within the MSA. The resulting model encodes both the position-specific conservation statistics and the correlated mutation statistics between sequential and long-range pairs of residues. Existing techniques for learning graphical models from MSA either make strong, and often inappropriate assumptions about the conditional independencies within the MSA (e.g., Hidden Markov Models), or else use suboptimal algorithms to learn the parameters of the model. In contrast, GREMLIN makes no a priori assumptions about the conditional independencies within the MSA. We formulate and solve a convex optimization problem, thus guaranteeing that we find a globally optimal model at convergence. The resulting model is also generative, allowing for the design of new protein sequences that have the same statistical properties as those in the MSA. We perform a detailed analysis of covariation statistics on the extensively studied WW and PDZ domains and show that our method out-performs an existing algorithm for learning undirected probabilistic graphical models from MSA. We then apply our approach to 71 additional families from the PFAM database and demonstrate that the resulting models significantly out-perform Hidden Markov Models in terms of predictive accuracy. Copyright © 2011 Wiley-Liss, Inc.

  7. wnt3a but not wnt11 supports self-renewal of embryonic stem cells

    International Nuclear Information System (INIS)

    Singla, Dinender K.; Schneider, David J.; LeWinter, Martin M.; Sobel, Burton E.

    2006-01-01

    wnt proteins (wnts) promote both differentiation of midbrain dopaminergic cells and self-renewal of haematopoietic stem cells. Mouse embryonic stem (ES) cells can be maintained and self-renew on mouse feeder cell layers or in media containing leukemia inhibitory factor (LIF). However, the effects of wnts on ES cells self-renewal and differentiation are not clearly understood. In the present study, we found that conditioned medium prepared from L cells expressing wnt3a can replace feeder cell layers and medium containing LIF in maintaining ES cells in the proliferation without differentiation (self-renewal) state. By contrast, conditioned medium from NIH3T3 cells expressing wnt11 did not. Alkaline phosphatase staining and compact colony formation were used as criteria of cells being in the undifferentiated state. ES cells maintained in medium conditioned by Wnt3a expressing cells underwent freezing and thawing while maintaining properties seen with LIF maintained ES cells. Purified wnt3a did not maintain self-renewal of ES cells for prolonged intervals. Thus, other factors in the medium conditioned by wnt3a expressing cells may have contributed to maintenance of ES cells in a self-renewal state. Pluripotency of ES cells was determined with the use of embryoid bodies in vitro. PD98059, a MEK specific inhibitor, promoted the growth of undifferentiated ES cells maintained in conditioned medium from wnt3a expressing cells. By contrast, the P38 MAPK inhibitor SB230580 did not, suggesting a role for the MEK pathway in self-renewal and differentiation of ES cells maintained in the wnt3a cell conditioned medium. Thus, our results show that conditioned medium from wnt3a but not wnt11 expressing cells can maintain ES cells in self-renewal and in a pluripotent state

  8. Mesenchymal Wnt/β-catenin signaling limits tooth number.

    Science.gov (United States)

    Järvinen, Elina; Shimomura-Kuroki, Junko; Balic, Anamaria; Jussila, Maria; Thesleff, Irma

    2018-02-21

    Tooth agenesis is one of the predominant developmental anomalies in humans, usually affecting the permanent dentition generated by sequential tooth formation and, in most cases, caused by mutations perturbing epithelial Wnt/β-catenin signaling. In addition, loss-of-function mutations in the Wnt feedback inhibitor AXIN2 lead to human tooth agenesis. We have investigated the functions of Wnt/β-catenin signaling during sequential formation of molar teeth using mouse models. Continuous initiation of new teeth, which is observed after genetic activation of Wnt/β-catenin signaling in the oral epithelium, was accompanied by enhanced expression of Wnt antagonists and a downregulation of Wnt/β-catenin signaling in the dental mesenchyme. Genetic and pharmacological activation of mesenchymal Wnt/β-catenin signaling negatively regulated sequential tooth formation, an effect partly mediated by Bmp4. Runx2 , a gene whose loss-of-function mutations result in sequential formation of supernumerary teeth in the human cleidocranial dysplasia syndrome, suppressed the expression of Wnt inhibitors Axin2 and Drapc1 in dental mesenchyme. Our data indicate that increased mesenchymal Wnt signaling inhibits the sequential formation of teeth, and suggest that Axin2 / Runx2 antagonistic interactions modulate the level of mesenchymal Wnt/β-catenin signaling, underlying the contrasting dental phenotypes caused by human AXIN2 and RUNX2 mutations. © 2018. Published by The Company of Biologists Ltd.

  9. ERAD-dependent control of the Wnt secretory factor Evi.

    Science.gov (United States)

    Glaeser, Kathrin; Urban, Manuela; Fenech, Emma; Voloshanenko, Oksana; Kranz, Dominique; Lari, Federica; Christianson, John C; Boutros, Michael

    2018-02-15

    Active regulation of protein abundance is an essential strategy to modulate cellular signaling pathways. Within the Wnt signaling cascade, regulated degradation of β-catenin by the ubiquitin-proteasome system (UPS) affects the outcome of canonical Wnt signaling. Here, we found that abundance of the Wnt cargo receptor Evi (Wls/GPR177), which is required for Wnt protein secretion, is also regulated by the UPS through endoplasmic reticulum (ER)-associated degradation (ERAD). In the absence of Wnt ligands, Evi is ubiquitinated and targeted for ERAD in a VCP-dependent manner. Ubiquitination of Evi involves the E2-conjugating enzyme UBE2J2 and the E3-ligase CGRRF1. Furthermore, we show that a triaging complex of Porcn and VCP determines whether Evi enters the secretory or the ERAD pathway. In this way, ERAD-dependent control of Evi availability impacts the scale of Wnt protein secretion by adjusting the amount of Evi to meet the requirement of Wnt protein export. As Wnt and Evi protein levels are often dysregulated in cancer, targeting regulatory ERAD components might be a useful approach for therapeutic interventions. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

  10. Expression of WNT genes in cervical cancer-derived cells: Implication of WNT7A in cell proliferation and migration

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Solano, Moisés, E-mail: mrsolano84@gmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); Meza-Canales, Ivan D., E-mail: imezacanales@ice.mpg.de [Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745 Jena (Germany); Torres-Reyes, Luis A., E-mail: torres_reyes_88@hotmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); Alvarez-Zavala, Monserrat, E-mail: monse_belan@hotmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); and others

    2015-07-01

    According to the multifactorial model of cervical cancer (CC) causation, it is now recognized that other modifications, in addition to Human papillomavirus (HPV) infection, are necessary for the development of this neoplasia. Among these, it has been proposed that a dysregulation of the WNT pathway might favor malignant progression of HPV-immortalized keratinocytes. The aim of this study was to identify components of the WNT pathway differentially expressed in CC vs. non-tumorigenic, but immortalized human keratinocytes. Interestingly, WNT7A expression was found strongly downregulated in cell lines and biopsies derived from CC. Restoration of WNT7A in CC-derived cell lines using a lentiviral gene delivery system or after adding a recombinant human protein decreases cell proliferation. Likewise, WNT7A silencing in non-tumorigenic cells markedly accelerates proliferation. Decreased WNT7A expression was due to hypermethylation at particular CpG sites. To our knowledge, this is the first study reporting reduced WNT7A levels in CC-derived cells and that ectopic WNT7A restoration negatively affects cell proliferation and migration. - Highlights: • WNT7A is expressed in normal keratinocytes or cervical cells without lesion. • WNT7A is significantly reduced in cervical cancer-derived cells. • Restoration of WNT7A expression in HeLa decreases proliferation and cell migration. • Silencing of WNT7A in HaCaT induces an increased proliferation and migration rate. • Decreased WNT7A expression in this model is due to hypermethylation.

  11. Expression of WNT genes in cervical cancer-derived cells: Implication of WNT7A in cell proliferation and migration

    International Nuclear Information System (INIS)

    Ramos-Solano, Moisés; Meza-Canales, Ivan D.; Torres-Reyes, Luis A.; Alvarez-Zavala, Monserrat

    2015-01-01

    According to the multifactorial model of cervical cancer (CC) causation, it is now recognized that other modifications, in addition to Human papillomavirus (HPV) infection, are necessary for the development of this neoplasia. Among these, it has been proposed that a dysregulation of the WNT pathway might favor malignant progression of HPV-immortalized keratinocytes. The aim of this study was to identify components of the WNT pathway differentially expressed in CC vs. non-tumorigenic, but immortalized human keratinocytes. Interestingly, WNT7A expression was found strongly downregulated in cell lines and biopsies derived from CC. Restoration of WNT7A in CC-derived cell lines using a lentiviral gene delivery system or after adding a recombinant human protein decreases cell proliferation. Likewise, WNT7A silencing in non-tumorigenic cells markedly accelerates proliferation. Decreased WNT7A expression was due to hypermethylation at particular CpG sites. To our knowledge, this is the first study reporting reduced WNT7A levels in CC-derived cells and that ectopic WNT7A restoration negatively affects cell proliferation and migration. - Highlights: • WNT7A is expressed in normal keratinocytes or cervical cells without lesion. • WNT7A is significantly reduced in cervical cancer-derived cells. • Restoration of WNT7A expression in HeLa decreases proliferation and cell migration. • Silencing of WNT7A in HaCaT induces an increased proliferation and migration rate. • Decreased WNT7A expression in this model is due to hypermethylation

  12. 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

  13. L-carnitine contributes to enhancement of neurogenesis from mesenchymal stem cells through Wnt/β-catenin and PKA pathway.

    Science.gov (United States)

    Fathi, Ezzatollah; Farahzadi, Raheleh; Charoudeh, Hojjatollah Nozad

    2017-03-01

    The identification of factors capable of enhancing neurogenesis has great potential for cellular therapies in neurodegenerative diseases. Multiple studies have shown the neuroprotective effects of L-carnitine (LC). This study determined whether neuronal differentiation of rat adipose tissue-derived mesenchymal stem cells (ADSCs) can be activated by LC. In this study, protein kinase A (PKA) and Wnt/β-catenin pathways were detected to show if this activation was due to these pathways. The expression of LC-induced neurogenesis markers in ADSCs was characterized using real-time PCR. ELISA was conducted to assess the expression of cyclic adenosine monophosphate (cAMP) and PKA. The expression of β-catenin, reduced dickkopf1 (DKK1), low-density lipoprotein receptor-related protein 5 (LRP5), Wnt1, and Wnt3a genes as Wnt/β-catenin signaling members were used to detect the Wnt/β-catenin pathway. It was observed that LC could promote neurogenesis in ADSCs as well as expression of some neurogenic markers. Moreover, LC causes to increase the cAMP levels and PKA activity. Treatment of ADSCs with H-89 (dihydrochloride hydrate) as PKA inhibitor significantly inhibited the promotion of neurogenic markers, indicating that the PKA signaling pathway could be involved in neurogenesis induction. Analyses of real-time PCR data showed that the mRNA expressions of β-catenin, DKK1, LRP5c-myc, Wnt1, and Wnt3a were increased in the presence of LC. Therefore, the present study showed that LC promotes ADSCs neurogenesis and the LC-induced neurogenic markers could be due to both the PKA and Wnt/β-catenin signaling pathway. Impact statement Neural tissue has long been believed as incapable of regeneration and the identification of cell types and factors capable of neuronal differentiation has generated intense interest. Mesenchymal stem cells (MSCs) are considered as potential targets for stem cell-based therapy. L-carnitin (LC) as an antioxidant may have neuroprotective effects in

  14. Antagonism between Hedgehog and Wnt signaling pathways regulates tumorigenicity.

    Science.gov (United States)

    Ding, Mei; Wang, Xin

    2017-12-01

    The crosstalk of multiple cellular signaling pathways is crucial in animal development and tissue homeostasis, and its dysregulation may result in tumor formation and metastasis. The Hedgehog (Hh) and Wnt signaling pathways are both considered to be essential regulators of cell proliferation, differentiation and oncogenesis. Recent studies have indicated that the Hh and Wnt signaling pathways are closely associated and involved in regulating embryogenesis and cellular differentiation. Hh signaling acts upstream of the Wnt signaling pathway, and negative regulates Wnt activity via secreted frizzled-related protein 1 (SFRP1), and the Wnt/β-catenin pathway downregulates Hh activity through glioma-associated oncogene homolog 3 transcriptional regulation. This evidence suggests that the imbalance of Hh and Wnt regulation serves a crucial role in cancer-associated processes. The activation of SFRP1, which inhibits Wnt, has been demonstrated to be an important cross-point between the two signaling pathways. The present study reviews the complex interaction between the Hh and Wnt signaling pathways in embryogenesis and tumorigenicity, and the role of SFRP1 as an important mediator associated with the dysregulation of the Hh and Wnt signaling pathways.

  15. Characterization of the Interaction of Sclerostin with the Low Density Lipoprotein Receptor-related Protein (LRP) Family of Wnt Co-receptors

    Czech Academy of Sciences Publication Activity Database

    Holdsworth, G.; Slocombe, P.; Doyle, C.; Sweeney, B.; Veverka, Václav; Le Riche, K.; Franklin, R. J.; Compson, J.; Brookings, D.; Turner, J.; Kennedy, J.; Garlish, R.; Shi, J.; Newnham, L.; McMillan, D.; Muzylak, M.; Carr, M. D.; Henry, A. J.; Ceska, T.; Robinson, M. K.

    2012-01-01

    Roč. 287, č. 32 (2012), s. 26464-26477 ISSN 0021-9258 Institutional research plan: CEZ:AV0Z40550506 Keywords : Wnt pathway * LRP * sclerostin Subject RIV: CE - Biochemistry Impact factor: 4.651, year: 2012

  16. Unterschiede und Gemeinsamkeiten der nicht-kanonischen Wnt-Liganden Wnt5a und Wnt11

    OpenAIRE

    Wallkamm, Veronika

    2014-01-01

    Die nicht-kanonischen Zweige des Wnt-Signalnetzwerkes sind Regulatoren der konvergenten Extension während der Xenopus Gastrulation. Dabei übernehmen die nicht-kanonischen Wnt-Liganden Wnt5a und Wnt11 nicht-redundante Aufgaben.

  17. beta-Arrestin Interacts with the Beta/Gamma Subunits of Trimeric G-Proteins and Dishevelled in the Wnt/Ca2+ Pathway in Xenopus Gastrulation

    Czech Academy of Sciences Publication Activity Database

    Seitz, K.; Dursch, V.; Harnoš, J.; Bryja, Vítězslav; Gentzel, M.; Schambony, A.

    2014-01-01

    Roč. 9, č. 1 (2014) E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GC204/09/J030 Grant - others:GA ČR(CZ) GA204/09/0498 Institutional support: RVO:68081707 Keywords : CONVERGENT EXTENSION MOVEMENTS * WNT SIGNALING PATHWAYS * WNT /BETA-CATENIN Subject RIV: BO - Biophysics Impact factor: 3.234, year: 2014

  18. 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

    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...... 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 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...

  19. Pharmacokinetic and pharmacodynamic considerations for the next generation protein therapeutics.

    Science.gov (United States)

    Shah, Dhaval K

    2015-10-01

    Increasingly sophisticated protein engineering efforts have been undertaken lately to generate protein therapeutics with desired properties. This has resulted in the discovery of the next generation of protein therapeutics, which include: engineered antibodies, immunoconjugates, bi/multi-specific proteins, antibody mimetic novel scaffolds, and engineered ligands/receptors. These novel protein therapeutics possess unique physicochemical properties and act via a unique mechanism-of-action, which collectively makes their pharmacokinetics (PK) and pharmacodynamics (PD) different than other established biological molecules. Consequently, in order to support the discovery and development of these next generation molecules, it becomes important to understand the determinants controlling their PK/PD. This review discusses the determinants that a PK/PD scientist should consider during the design and development of next generation protein therapeutics. In addition, the role of systems PK/PD models in enabling rational development of the next generation protein therapeutics is emphasized.

  20. Wnts and wing: Wnt signaling in vertebrate limb development and musculoskeletal morphogenesis.

    Science.gov (United States)

    Yang, Yingzi

    2003-11-01

    In the past twenty years, secreted signaling molecules of the Wnt family have been found to play a central role in controlling embryonic development from hydra to human. In the developing vertebrate limb, Wnt signaling is required for limb bud initiation, early limb patterning (which is governed by several well-characterized signaling centers), and, finally, late limb morphogenesis events. Wnt ligands are unique, in that they can activate several different receptor-mediated signal transduction pathways. The most extensively studied Wnt pathway is the canonical Wnt pathway, which controls gene expression by stabilizing beta-catenin in regulating a diverse array of biological processes. Recently, more attention has been given to the noncanonical Wnt pathway, which is beta-catenin-independent. The noncanonical Wnt pathway signals through activating Ca(2+) flux, JNK activation, and both small and heterotrimeric G proteins, to induce changes in gene expression, cell adhesion, migration, and polarity. Abnormal Wnt signaling leads to developmental defects and human diseases affecting either tissue development or homeostasis. Further understanding of the biological function and signaling mechanism of Wnt signaling is essential for the development of novel preventive and therapeutic approaches of human diseases. This review provides a critical perspective on how Wnt signaling regulates different developmental processes. As Wnt signaling in tumor formation has been reviewed extensively elsewhere, this part is not included in the review of the clinical significance of Wnt signaling.

  1. Targeting the Wnt/beta-catenin pathway in cancer: Update on effectors and inhibitors.

    Science.gov (United States)

    Krishnamurthy, Nithya; Kurzrock, Razelle

    2018-01-01

    The Wnt/beta-catenin pathway is a family of proteins that is implicated in many vital cellular functions such as stem cell regeneration and organogenesis. Several intra-cellular signal transduction pathways are induced by Wnt, notably the Wnt/beta-catenin dependent pathway or canonical pathway and the non-canonical or beta-catenin-independent pathway; the latter includes the Wnt/Ca2+ and Planar Cell Polarity pathway (PCP). Wnt activation occurs at the intestinal crypt floor, and is critical to optimal maintenance of stem cells. Colorectal cancers show evidence of Wnt signaling pathway activation and this is associated with loss of function of the tumor regulator APC. Wnt activation has been observed in breast, lung, and hematopoietic malignancies and contributes to tumor recurrence. The Wnt pathway cross talks with the Notch and Sonic Hedgehog pathways, which has implications for therapeutic interventions in cancers. There are significant challenges in targeting the Wnt pathway, including finding agents that are efficacious without damaging the system of normal somatic stem cell function in cellular repair and tissue homeostasis. Here, we comprehensively review the Wnt pathway and its interactions with the Notch and Sonic Hedgehog pathways. We present the state of the field in effectors and inhibitors of Wnt signaling, including updates on clinical trials in various cancers with inhibitors of Wnt, Notch, and Sonic Hedgehog. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. CD133-positive dermal papilla-derived Wnt ligands regulate postnatal hair growth.

    Science.gov (United States)

    Zhou, Linli; Yang, Kun; Carpenter, April; Lang, Richard A; Andl, Thomas; Zhang, Yuhang

    2016-10-01

    Active Wnt/β-catenin signaling in the dermal papilla (DP) is required for postnatal hair cycling. In addition, maintenance of the hair-inducing ability of DP cells in vitro requires external addition of Wnt molecules. However, whether DP cells are a critical source of Wnt ligands and induce both autocrine and paracrine signaling cascades to promote adult hair follicle growth and regeneration remains elusive. To address this question, we generated an animal model that allows inducible ablation of Wntless (Wls), a transmembrane Wnt exporter protein, in CD133-positive (CD133+) DP cells. CD133+ cells have been shown to be a specific subpopulation of cells in the DP, which possesses the hair-inducing capability. Here, we show that ablation of Wls expression in CD133+ DP cells results in a shortened period of postnatal hair growth. Mutant hair follicles were unable to enter full anagen (hair growth stage) and progressed toward a rapid regression. Notably, reduced size of the DP and decreased expression of anagen DP marker, versican, were observed in hair follicles when CD133+ DP cells lost Wls expression. Further analysis showed that Wls-deficient CD133+ DP cells led to reduced proliferation and differentiation in matrix keratinocytes and melanocytes that are needed for the generation of the hair follicle structure and a pigmented hair shaft. These findings clearly demonstrate that Wnt ligands produced by CD133+ DP cells play an important role in postnatal hair growth by maintaining the inductivity of DP cells and mediating the signaling cross-talk between the mesenchyme and the epithelial compartment. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  3. Wnt-5a/Frizzled9 Receptor Signaling through the Gαo-Gβγ Complex Regulates Dendritic Spine Formation*

    Science.gov (United States)

    Ramírez, Valerie T.; Ramos-Fernández, Eva; Henríquez, Juan Pablo; Lorenzo, Alfredo; Inestrosa, Nibaldo C.

    2016-01-01

    Wnt ligands play crucial roles in the development and regulation of synapse structure and function. Specifically, Wnt-5a acts as a secreted growth factor that regulates dendritic spine formation in rodent hippocampal neurons, resulting in postsynaptic development that promotes the clustering of the PSD-95 (postsynaptic density protein 95). Here, we focused on the early events occurring after the interaction between Wnt-5a and its Frizzled receptor at the neuronal cell surface. Additionally, we studied the role of heterotrimeric G proteins in Wnt-5a-dependent synaptic development. We report that FZD9 (Frizzled9), a Wnt receptor related to Williams syndrome, is localized in the postsynaptic region, where it interacts with Wnt-5a. Functionally, FZD9 is required for the Wnt-5a-mediated increase in dendritic spine density. FZD9 forms a precoupled complex with Gαo under basal conditions that dissociates after Wnt-5a stimulation. Accordingly, we found that G protein inhibition abrogates the Wnt-5a-dependent pathway in hippocampal neurons. In particular, the activation of Gαo appears to be a key factor controlling the Wnt-5a-induced dendritic spine density. In addition, we found that Gβγ is required for the Wnt-5a-mediated increase in cytosolic calcium levels and spinogenesis. Our findings reveal that FZD9 and heterotrimeric G proteins regulate Wnt-5a signaling and dendritic spines in cultured hippocampal neurons. PMID:27402827

  4. SGK1 (glucose transport), dishevelled2 (wnt signaling), LC3/p62 (autophagy) and p53 (apoptosis) proteins are unaltered in Lafora disease

    Energy Technology Data Exchange (ETDEWEB)

    Wang, P.; Israelian, L.; Xue, Y.; Song, S.; Attisano, L.; Minassian, B.

    2016-07-01

    Glycogen forms through the concerted actions of glycogen synthase (GS) which elongates glycogen strands, and glycogen branching enzyme (GBE). Lafora disease (LD) is a fatal neurodegenerative epilepsy that results from neuronal accumulation of hyperphosphorylated glycogen with excessively long strands (called polyglucosans). There is no GBE deficiency in LD. Instead, the disease is caused by loss-of-function mutations in the EPM2A or EPM2B genes, encoding, respectively, a phosphatase, laforin, and an E3 ubiquiting ligase, malin. A number of experimentally derived hypotheses have been published to explain LD, including: The SGK1 hypothesis - Phosphorylated SGK1 (pSGK1) raises cellular glucose uptake and levels, which would activate GS. Based on observing increased pSGK1 in LD mice it was proposed that raised pSGK1 leads to polyglucosan generation through GS hyperactivation. The Dishevelled2 hypothesis - Downregulating malin in cell culture was reported to increase levels of dishevelled2, which through the wnt/glycogen synthase kinase-3 pathway would likewise overactivate GS. The Autophagic defect hypothesis - Polyglucosans may be natural byproducts of normal glycogen metabolism. LD mice were reported to be autophagy-defective. LD would arise from failed autophagy leading to failed polyglucosan clearance. Finally, the p53 hypothesis - laforin and malin were reported to downregulate p53, their absence leading to increased p53, which would activate apoptosis, leading to the neurodegeneration of LD. In the present work we repeat key experiments that underlie these four hypotheses. We are unable to confirm increased pSGK1, dishevelled2, or p53 in LD mice, nor the reported autophagic defects. Our work does not support the above hypotheses in understanding this unique and severe form of epilepsy.

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

    International Nuclear Information System (INIS)

    Santiago, Francisco; Oguma, Junya; Brown, Anthony M.C.; Laurence, Jeffrey

    2012-01-01

    Highlights: ► First demonstration of direct role for noncanonical Wnt in osteoclast differentiation. ► Demonstration of Ryk as a Wnt5a/b receptor in inhibition of canonical Wnt signaling. ► Modulation of noncanonical Wnt signaling by a clinically important drug, ritonavir. ► Establishes a mechanism for an important clinical problem: HIV-associated bone loss. -- Abstract: Wnt proteins that signal via the canonical Wnt/β-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 β-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, β-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 regulation of osteoclast differentiation, and its modulation by a clinically important drug, ritonavir. These studies

  6. Wnt signaling in limb organogenesis

    OpenAIRE

    Geetha-Loganathan, Poongodi; Nimmagadda, Suresh; Scaal, Martin

    2008-01-01

    Secreted signaling molecules of the Wnt family have been found to play a central role in controlling embryonic development of a wide range of taxa from Hydra to humans. The most extensively studied Wnt signaling pathway is the canonical Wnt pathway, which controls gene expression by stabilizing β-catenin, and regulates a multitude of developmental processes. More recently, noncanonical Wnt pathways, which are β-catenin-independent, have been found to be important developmental regulators. Und...

  7. WNT5A inhibits human dental papilla cell proliferation and migration

    Energy Technology Data Exchange (ETDEWEB)

    Peng, L. [West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan (China); State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, Sichuan (China); Ye, L.; Dong, G.; Ren, L.B.; Wang, C.L.; Xu, P. [West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan (China); Zhou, X.D., E-mail: pl_huaxi@yahoo.com.cn [West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan (China); State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, Sichuan (China)

    2009-12-18

    WNT proteins are a large family of cysteine-rich secreted molecules that are linked to both canonical and non-canonical signal pathways, and have been implicated in oncogenesis and tissue development. Canonical WNT proteins have been proven to play critical roles in tooth development, while little is known about the role of non-canonical WNT proteins such as WNT5A. In this study, WNT5A was localized to human dental papilla tissue and human dental papilla cells (HDPCs) cultured in vitro, using immunochemistry and RT-PCR. Recombinant adenovirus encoding full-length Wnt5a cDNA was constructed to investigate the biological role of WNT5A on HDPCs. The BrdU incorporation assay, the MTT assay and flow cytometric analysis showed that over-expression of Wnt5a strongly inhibited the proliferation of HDPCs in vitro. Wound healing and transwell migration assays indicated that over-expression of WNT5A reduced migration of HDPCs. In conclusion, our results showed that WNT5A negatively regulates both proliferation and migration of HDPCs, suggesting its important role in odontogenesis via controlling the HDPCs.

  8. Wnt signaling-mediated redox regulation maintains the germ line stem cell differentiation niche.

    Science.gov (United States)

    Wang, Su; Gao, Yuan; Song, Xiaoqing; Ma, Xing; Zhu, Xiujuan; Mao, Ying; Yang, Zhihao; Ni, Jianquan; Li, Hua; Malanowski, Kathryn E; Anoja, Perera; Park, Jungeun; Haug, Jeff; Xie, Ting

    2015-10-09

    Adult stem cells continuously undergo self-renewal and generate differentiated cells. In the Drosophila ovary, two separate niches control germ line stem cell (GSC) self-renewal and differentiation processes. Compared to the self-renewing niche, relatively little is known about the maintenance and function of the differentiation niche. In this study, we show that the cellular redox state regulated by Wnt signaling is critical for the maintenance and function of the differentiation niche to promote GSC progeny differentiation. Defective Wnt signaling causes the loss of the differentiation niche and the upregulated BMP signaling in differentiated GSC progeny, thereby disrupting germ cell differentiation. Mechanistically, Wnt signaling controls the expression of multiple glutathione-S-transferase family genes and the cellular redox state. Finally, Wnt2 and Wnt4 function redundantly to maintain active Wnt signaling in the differentiation niche. Therefore, this study has revealed a novel strategy for Wnt signaling in regulating the cellular redox state and maintaining the differentiation niche.

  9. Dual inhibition of Wnt and Yes-associated protein signaling retards the growth of triple-negative breast cancer in both mesenchymal and epithelial states.

    Science.gov (United States)

    Sulaiman, Andrew; McGarry, Sarah; Li, Li; Jia, Deyong; Ooi, Sarah; Addison, Christina; Dimitroulakos, Jim; Arnaout, Angel; Nessim, Carolyn; Yao, Zemin; Ji, Guang; Song, Haiyan; Gadde, Suresh; Li, Xuguang; Wang, Lisheng

    2018-04-01

    Triple-negative breast cancer (TNBC), the most refractory subtype of breast cancer to current treatments, accounts disproportionately for the majority of breast cancer-related deaths. This is largely due to cancer plasticity and the development of cancer stem cells (CSCs). Recently, distinct yet interconvertible mesenchymal-like and epithelial-like states have been revealed in breast CSCs. Thus, strategies capable of simultaneously inhibiting bulk and CSC populations in both mesenchymal and epithelial states have yet to be developed. Wnt/β-catenin and Hippo/YAP pathways are crucial in tumorigenesis, but importantly also possess tumor suppressor functions in certain contexts. One possibility is that TNBC cells in epithelial or mesenchymal state may differently affect Wnt/β-catenin and Hippo/YAP signaling and CSC phenotypes. In this report, we found that YAP signaling and CD44 high /CD24 -/low CSCs were upregulated while Wnt/β-catenin signaling and ALDH+ CSCs were downregulated in mesenchymal-like TNBC cells, and vice versa in their epithelial-like counterparts. Dual knockdown of YAP and Wnt/β-catenin, but neither alone, was required for effective suppression of both CD44 high /CD24 -/low and ALDH+ CSC populations in mesenchymal and epithelial TNBC cells. These observations were confirmed with cultured tumor fragments prepared from patients with TNBC after treatment with Wnt inhibitor ICG-001 and YAP inhibitor simvastatin. In addition, a clinical database showed that decreased gene expression of Wnt and YAP was positively correlated with decreased ALDH and CD44 expression in patients' samples while increased patient survival. Furthermore, tumor growth of TNBC cells in either epithelial or mesenchymal state was retarded, and both CD44 high /CD24 -/low and ALDH+ CSC subpopulations were diminished in a human xenograft model after dual administration of ICG-001 and simvastatin. Tumorigenicity was also hampered after secondary transplantation. These data suggest a new

  10. Wnt-11 promotes neuroendocrine-like differentiation, survival and migration of prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Diez Soraya

    2010-03-01

    Full Text Available Abstract Background Wnt-11 is a secreted protein that modulates cell growth, differentiation and morphogenesis during development. We previously reported that Wnt-11 expression is elevated in hormone-independent prostate cancer and that the progression of prostate cancer from androgen-dependent to androgen-independent proliferation correlates with a loss of mutual inhibition between Wnt-11- and androgen receptor-dependent signals. However, the prevalence of increased expression of Wnt-11 in patient tumours and the functions of Wnt-11 in prostate cancer cells were not known. Results Wnt-11 protein levels in prostate tumours were determined by immunohistochemical analysis of prostate tumour tissue arrays. Wnt-11 protein was elevated in 77/117 of tumours when compared with 27 benign prostatic hypertrophy specimens and was present in 4/4 bone metastases. In addition, there was a positive correlation between Wnt-11 expression and PSA levels above 10 ng/ml. Androgen-depleted LNCaP prostate cancer cells form neurites and express genes associated with neuroendocrine-like differentiation (NED, a feature of prostate tumours that have a poor prognosis. Since androgen-depletion increases expression of Wnt-11, we examined the role of Wnt-11 in NED. Ectopic expression of Wnt-11 induced expression of NSE and ASCL1, which are markers of NED, and this was prevented by inhibitors of cyclic AMP-dependent protein kinase, consistent with the known role of this kinase in NED. In contrast, Wnt-11 did not induce NSE expression in RWPE-1 cells, which are derived from benign prostate, suggesting that the role of Wnt-11 in NED is specific to prostate cancer. In addition, silencing of Wnt-11 expression in androgen-depleted LNCaP cells prevented NED and resulted in apoptosis. Silencing of Wnt-11 gene expression in androgen-independent PC3 cells also reduced expression of NSE and increased apoptosis. Finally, silencing of Wnt-11 reduced PC3 cell migration and ectopic

  11. Activation of Wnt/beta-catenin signaling increases insulin sensitivity through a reciprocal regulation of Wnt10b and SREBP-1c in skeletal muscle cells.

    Directory of Open Access Journals (Sweden)

    Mounira Abiola

    2009-12-01

    Full Text Available Intramyocellular lipid accumulation is strongly related to insulin resistance in humans, and we have shown that high glucose concentration induced de novo lipogenesis and insulin resistance in murin muscle cells. Alterations in Wnt signaling impact the balance between myogenic and adipogenic programs in myoblasts, partly due to the decrease of Wnt10b protein. As recent studies point towards a role for Wnt signaling in the pathogenesis of type 2 diabetes, we hypothesized that activation of Wnt signaling could play a crucial role in muscle insulin sensitivity.Here we demonstrate that SREBP-1c and Wnt10b display inverse expression patterns during muscle ontogenesis and regeneration, as well as during satellite cells differentiation. The Wnt/beta-catenin pathway was reactivated in contracting myotubes using siRNA mediated SREBP-1 knockdown, Wnt10b over-expression or inhibition of GSK-3beta, whereas Wnt signaling was inhibited in myoblasts through silencing of Wnt10b. SREBP-1 knockdown was sufficient to induce Wnt10b protein expression in contracting myotubes and to activate the Wnt/beta-catenin pathway. Conversely, silencing Wnt10b in myoblasts induced SREBP-1c protein expression, suggesting a reciprocal regulation. Stimulation of the Wnt/beta-catenin pathway i drastically decreased SREBP-1c protein and intramyocellular lipid deposition in myotubes; ii increased basal glucose transport in both insulin-sensitive and insulin-resistant myotubes through a differential activation of Akt and AMPK pathways; iii restored insulin sensitivity in insulin-resistant myotubes.We conclude that activation of Wnt/beta-catenin signaling in skeletal muscle cells improved insulin sensitivity by i decreasing intramyocellular lipid deposition through downregulation of SREBP-1c; ii increasing insulin effects through a differential activation of the Akt/PKB and AMPK pathways; iii inhibiting the MAPK pathway. A crosstalk between these pathways and Wnt/beta-catenin signaling

  12. Role of TRIM33 in Wnt signaling during mesendoderm differentiation.

    Science.gov (United States)

    Xia, Xiaojie; Zuo, Feifei; Luo, Maoguo; Sun, Ye; Bai, Jianbo; Xi, Qiaoran

    2017-10-01

    Tripartite motif 33 (TRIM33), a member of the transcription intermediate factor 1 (TIF1) family of transcription cofactors, mediates transforming growth factor-beta (TGF-β) signaling through its PHD-Bromo cassette in mesendoderm differentiation during early mouse embryonic development. However, the role of the TRIM33 RING domain in embryonic differentiation is less clear. Here, we report that TRIM33 mediates Wnt signaling by directly regulating the expression of a specific subset of Wnt target genes, and this action is independent of its RING domain. We show that TRIM33 interacts with β-catenin, a central player in Wnt signaling in mouse embryonic stem cells (mESCs). In contrast to previous reports in cancer cell lines, the RING domain does not appear to function as the E3 ligase for β-catenin, since neither knockout nor overexpression of TRIM33 had an effect on β-catenin protein levels in mESCs. Furthermore, we show that although TRIM33 seems to be dispensable for Wnt signaling through a reporter assay, loss of TRIM33 significantly impairs the expression of a subset of Wnt target genes, including Mixl1, in a Wnt signaling-dependent manner. Together, our results indicate that TRIM33 regulates Wnt signaling independent of the E3 ligase activity of its RING domain for β-catenin in mESCs.

  13. Efficient Purification and Optimization of Wnt3a, a Novel Therapeutic for Tissue Regeneration

    Science.gov (United States)

    Madhav, D.; Helms, J.; Dhamdhere, G.

    2012-12-01

    Wnt is a secreted protein that is present naturally in the body. When an organism is injured the amount of Wnt in the affected area increases. This protein acts as an activator of adult stem cells and signals them to begin differentiating and proliferating. This stem cell response augments the ongoing efforts of injured cells to heal faster by becoming the cells that were damaged by the injury. Adult stem cells play a great role in the healing of wounds, but as organisms age the amount of stem cells in their body decreases. This decrease, in effect, slows the healing of injuries because no stem cells are present to help the regenerative efforts of the body. The Wnt protein induces these stem cells not only to differentiate and proliferate, but also to self-replicate. The ability of Wnt to induce adult stem cells to self -replicate gives us an option to use the protein as a potential tissue regenerative drug. Post-translational Wnt has a lipid modification that makes the protein insoluble in water. To overcome this we fuse the protein with a liposome. A liposome is a lipid sphere with an aqueous center and a phospholipid membrane. The Wnt protein does not lose its function when joined with a liposome. Using this knowledge we can develop a viable means to inject the Wnt protein directly into organisms. The big problem now is to make enough purified Wnt to manufacture on a large scale.

  14. Porcupine inhibitor suppresses paracrine Wnt-driven growth of Rnf43;Znrf3-mutant neoplasia

    NARCIS (Netherlands)

    Koo, Bon-Kyoung; van Es, Johan H; van den Born, Maaike; Clevers, Hans

    2015-01-01

    Rnf43 (RING finger protein 43) and Znrf3 (zinc/RING finger protein 3) (RZ) are two closely related transmembrane E3 ligases, encoded by Wnt target genes, that remove surface Wnt (wingless-int) receptors. The two genes are mutated in various human cancers. Such tumors are predicted to be

  15. Identification and expression characterization of WntA during intestinal regeneration in the sea cucumber Apostichopus japonicus.

    Science.gov (United States)

    Li, Xiaoni; Sun, Lina; Yang, Hongsheng; Zhang, Libin; Miao, Ting; Xing, Lili; Huo, Da

    2017-08-01

    Wnt genes encode secreted glycoproteins that act as signaling molecules; these molecules direct cell proliferation, migration, differentiation and survival during animal development, maintenance of homeostasis and regeneration. At present, although the regeneration mechanism in Apostichopus japonicus has been studied, there is a little research on the Wnt signaling pathway in A. japonicus. To understand the potential role of the Wnt signaling pathway in A. japonicus, we cloned and sequenced the WntA gene in A. japonicus. Protein localization analysis showed that WntA protein was ubiquitously expressed in epidermal cells, the muscle and submucosa of the intestinal tissue. After stimulation and evisceration, the dynamic changes in expression of the WntA gene and protein showed that WntA was constitutively expressed during different stages of intestine regeneration in A. japonicus, with higher levels during the early wound healing stage and late lumen formation in the residual and nascent intestinal tissues, indicating its response to intestinal regeneration. Simultaneously, cell proliferation and apoptosis analysis showed that the patterns of cell proliferation were similar to the patterns of WntA protein expression during different intestinal regeneration stages in this organism. Taken together, these results suggested that WntA might participate in intestinal regeneration and may be connected with cell proliferation, apoptosis in different intestinal layers. This research could establish a basis for further examination of WntA functions in A. japonicus and Wnt genes in other echinoderms. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. RhoA Controls Wnt Upregulation on Microstructured Titanium Surfaces

    Directory of Open Access Journals (Sweden)

    Simone Lumetti

    2014-01-01

    Full Text Available Rough topography enhances the activation of Wnt canonical signaling in vitro, and this mediates its effects on cell differentiation. However, the molecular mechanisms underlying topography-dependent control of Wnt signaling are still poorly understood. As the small GTPase RhoA controls cytoskeletal reorganization and actomyosin-induced tensional forces, we hypothesized that RhoA could affect the activation of Wnt signaling in cells on micropatterned titanium surfaces. G-LISA assay revealed that RhoA activation was higher in C2C12 cells on rough (SLA surfaces under basal conditions than on smooth (Polished titanium. Transfection with dominant negative RhoA decreased Wnt activation by normalized TCF-Luc activity on SLA, whilst transfection with constitutively active RhoA increased TCF-Luc activation on Polished titanium. One mM Myosin II inhibitor Blebbistatin increased RhoA activation but decreased Wnt activation on SLA surfaces, indicating that tension-generating structures are required for canonical Wnt modulation on titanium surfaces. Actin inhibitor Cytochalasin markedly enhanced RhoA and TCF-Luc activation on both surfaces and increased the expression of differentiation markers in murine osteoblastic MC3T3 cells. Taken together, these data show that RhoA is upregulated in cells on rough surfaces and it affects the activation of Wnt canonical signaling through Myosin II modulation.

  17. 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.

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

    Science.gov (United States)

    2010-01-01

    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. PMID:20920349

  19. Wnt pathway activity in breast cancer sub-types and stem-like cells.

    Directory of Open Access Journals (Sweden)

    Rebecca Lamb

    Full Text Available INTRODUCTION: Wnt signalling has been implicated in stem cell regulation however its role in breast cancer stem cell regulation remains unclear. METHODS: We used a panel of normal and breast cancer cell lines to assess Wnt pathway gene and protein expression, and for the investigation of Wnt signalling within stem cell-enriched populations, mRNA and protein expression was analysed after the selection of anoikis-resistant cells. Finally, cell lines and patient-derived samples were used to investigate Wnt pathway effects on stem cell activity in vitro. RESULTS: Wnt pathway signalling increased in cancer compared to normal breast and in both cell lines and patient samples, expression of Wnt pathway genes correlated with estrogen receptor (ER expression. Furthermore, specific Wnt pathway genes were predictive for recurrence within subtypes of breast cancer. Canonical Wnt pathway genes were increased in breast cancer stem cell-enriched populations in comparison to normal breast stem cell-enriched populations. Furthermore in cell lines, the ligand Wnt3a increased whilst the inhibitor DKK1 reduced mammosphere formation with the greatest inhibitory effects observed in ER+ve breast cancer cell lines. In patient-derived metastatic breast cancer samples, only ER-ve mammospheres were responsive to the ligand Wnt3a. However, the inhibitor DKK1 efficiently inhibited both ER+ve and ER-ve breast cancer but not normal mammosphere formation, suggesting that the Wnt pathway is aberrantly activated in breast cancer mammospheres. CONCLUSIONS: Collectively, these data highlight differential Wnt signalling in breast cancer subtypes and activity in patient-derived metastatic cancer stem-like cells indicating a potential for Wnt-targeted treatment in breast cancers.

  20. Prediction of structure of human WNT-CRD (FZD complex for computational drug repurposing.

    Directory of Open Access Journals (Sweden)

    Qurrat U Ain

    Full Text Available The observed genetic alterations of various extracellular and intracellular WNT (Wingless, Int-1 proto-oncogene signaling components can result in an increase or decrease in gene expression, and hence can be obstructed proficiently. These genetics target sites may include the prevention of WNT-FZD (Frizzled binding, destruction of β-catenin and formation of Axin, APC and GSK-3β complex. Hence, the localized targeting of these interacting partners can help in devising novel inhibitors against WNT signaling. Our present study is an extension of our previous work, in which we proposed the co-regulated expression pattern of the WNT gene cluster (WNT-1, WNT-6, WNT-10A and WNT-10B in human breast carcinoma. We present here the computationally modeled three dimensional structure of human WNT-1 in complex with the FZD-1 CRD (Cysteine Rich Domain receptor. The dimeric cysteine-rich domain was found to fit into the evolutionarily conserved U-shaped groove of WNT protein. The two ends of the U- shaped cleft contain N-terminal and C-terminal hydrophobic residues, thus providing a strong hydrophobic moiety for the frizzled receptor and serving as the largest binding pocket for WNT-FZD interaction. Detailed structural analysis of this cleft revealed a maximum atomic distance of ~28 Å at the surface, narrowing down to ~17 Å and again increasing up to ~27 Å at the bottom. Altogether, structural prediction analysis of WNT proteins was performed to reveal newer details about post-translational modification sites and to map the novel pharmacophore models for potent WNT inhibitors.

  1. Wnt-pathway activation in two molecular classes of hepatocellular carcinoma and experimental modulation by sorafenib.

    Science.gov (United States)

    Lachenmayer, Anja; Alsinet, Clara; Savic, Radoslav; Cabellos, Laia; Toffanin, Sara; Hoshida, Yujin; Villanueva, Augusto; Minguez, Beatriz; Newell, Philippa; Tsai, Hung-Wen; Barretina, Jordi; Thung, Swan; Ward, Stephen C; Bruix, Jordi; Mazzaferro, Vincenzo; Schwartz, Myron; Friedman, Scott L; Llovet, Josep M

    2012-09-15

    Hepatocellular carcinoma (HCC) is a heterogeneous cancer with active Wnt signaling. Underlying biologic mechanisms remain unclear and no drug targeting this pathway has been approved to date. We aimed to characterize Wnt-pathway aberrations in HCC patients, and to investigate sorafenib as a potential Wnt modulator in experimental models of liver cancer. The Wnt-pathway was assessed using mRNA (642 HCCs and 21 liver cancer cell lines) and miRNA expression data (89 HCCs), immunohistochemistry (108 HCCs), and CTNNB1-mutation data (91 HCCs). Effects of sorafenib on Wnt signaling were evaluated in four liver cancer cell lines with active Wnt signaling and a tumor xenograft model. Evidence for Wnt activation was observed for 315 (49.1%) cases, and was further classified as CTNNB1 class (138 cases [21.5%]) or Wnt-TGFβ class (177 cases [27.6%]). CTNNB1 class was characterized by upregulation of liver-specific Wnt-targets, nuclear β-catenin and glutamine-synthetase immunostaining, and enrichment of CTNNB1-mutation-signature, whereas Wnt-TGFβ class was characterized by dysregulation of classical Wnt-targets and the absence of nuclear β-catenin. Sorafenib decreased Wnt signaling and β-catenin protein in HepG2 (CTNNB1 class), SNU387 (Wnt-TGFβ class), SNU398 (CTNNB1-mutation), and Huh7 (lithium-chloride-pathway activation) cell lines. In addition, sorafenib attenuated expression of liver-related Wnt-targets GLUL, LGR5, and TBX3. The suppressive effect on CTNNB1 class-specific Wnt-pathway activation was validated in vivo using HepG2 xenografts in nude mice, accompanied by decreased tumor volume and increased survival of treated animals. Distinct dysregulation of Wnt-pathway constituents characterize two different Wnt-related molecular classes (CTNNB1 and Wnt-TGFβ), accounting for half of all HCC patients. Sorafenib modulates β-catenin/Wnt signaling in experimental models that harbor the CTNNB1 class signature. ©2012 AACR.

  2. Cotargeting VEGF and Neuropilins With Bevacizumab and Secreted Wnt Inhibitors in Prostate Cancer

    Science.gov (United States)

    2013-09-01

    Bevacizumab and Secreted Wnt Inhibitors in Prostate Cancer PRINCIPAL INVESTIGATOR: Xiaolin Zi CONTRACTING ORGANIZATION: University of...With Bevacizumab and Secreted Wnt Inhibitors in Prostate Cancer” 5b. GRANT NUMBER W81XWH-11-1-0312 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...cleavage. In addition, our results showed that Bevacizumab increased Wnt signaling and expression of c-Met and NRP2 protein, leading to increased migration

  3. Identification of Noncanonical Wnt Receptors Required for Wnt-3a-Induced Early Differentiation of Human Neural Stem Cells.

    Science.gov (United States)

    Bengoa-Vergniory, Nora; Gorroño-Etxebarria, Irantzu; López-Sánchez, Inmaculada; Marra, Michele; Di Chiaro, Pierluigi; Kypta, Robert

    2017-10-01

    Wnt proteins preferentially activate either β-catenin-dependent or β-catenin-independent signals, but the activity of a particular Wnt also depends on cellular context and receptor availability. We previously reported that Wnt-3a induces neural differentiation of human embryonic stem cell-derived neural stem cells (NSCs) in a β-catenin-independent manner by activating a signal involving JNK and the AP-1 family member ATF-2. Here, we report the results of a gene silencing approach to identify the Wnt receptors that mediate this response to Wnt-3a. Silencing of ROR2 increased neuronal differentiation, as measured by expression of the genes DCX, NEUROD1, and NGN1, suggesting ROR2 signals normally prevent differentiation. Silencing of the other Wnt receptors singly did not affect Wnt-3a-induced neuronal differentiation. However, pairwise silencing of ROR1 and FZD4 or FZD5 and of LRP6 and FZD4 or FZD5 inhibited neuronal differentiation, as detected by reductions in the expression of neuronal genes and immunocytochemical detection of DCX, NEUROD1 and DCX. Ectopic expression of these receptors in HEK 293 cells increased ATF2-dependent transcription. In addition, ROR1 coimmunoprecipitated with FZD4 and LRP6 in transfected HEK 293 cells and colocalized with FZD4 and with LRP6 at the cell surface of transfected L cells. Wnt-3a did not appear to affect these interactions but did alter the interactions between LRP6 and FZD4/5. Together, these observations highlight roles for ROR1, LRP6, FZD4, and FZD5 in neural stem cell differentiation and provide support for a model in which dynamic interactions among these receptors mediate Wnt-3a activation of ATF2 signaling.

  4. Wnt/β-catenin signaling changes C2C12 myoblast proliferation and differentiation by inducing Id3 expression

    International Nuclear Information System (INIS)

    Zhang, Long; Shi, Songting; Zhang, Juan; Zhou, Fangfang; Dijke, Peter ten

    2012-01-01

    Highlights: ► Expression of Id3 but not Id1 is induced by Wnt3a stimulation in C2C12 cells. ► Wnt3a induces Id3 expression via canonical Wnt/β-catenin pathway. ► Wnt3a-induced Id3 expression does not depend on BMP signaling activation. ► Induction of Id3 expression is critical determinant in Wnt3a-induced cell proliferation and differentiation. -- Abstract: Canonical Wnt signaling plays important roles in regulating cell proliferation and differentiation. In this study, we report that inhibitor of differentiation (Id)3 is a Wnt-inducible gene in mouse C2C12 myoblasts. Wnt3a induced Id3 expression in a β-catenin-dependent manner. Bone morphogenetic protein (BMP) also potently induced Id3 expression. However, Wnt-induced Id3 expression occurred independent of the BMP/Smad pathway. Functional studies showed that Id3 depletion in C2C12 cells impaired Wnt3a-induced cell proliferation and alkaline phosphatase activity, an early marker of osteoblast cells. Id3 depletion elevated myogenin induction during myogenic differentiation and partially impaired Wnt3a suppressed myogenin expression in C2C12 cells. These results suggest that Id3 is an important Wnt/β-catenin induced gene in myoblast cell fate determination.

  5. An in vitro fatty acylation assay reveals a mechanism for Wnt recognition by the acyltransferase Porcupine.

    Science.gov (United States)

    Asciolla, James J; Miele, Matthew M; Hendrickson, Ronald C; Resh, Marilyn D

    2017-08-18

    Wnt proteins are a family of secreted signaling proteins that play key roles in regulating cell proliferation in both embryonic and adult tissues. Production of active Wnt depends on attachment of palmitoleate, a monounsaturated fatty acid, to a conserved serine by the acyltransferase Porcupine (PORCN). Studies of PORCN activity relied on cell-based fatty acylation and signaling assays as no direct enzyme assay had yet been developed. Here, we present the first in vitro assay that accurately recapitulates PORCN-mediated fatty acylation of a Wnt substrate. The critical feature is the use of a double disulfide-bonded Wnt peptide that mimics the two-dimensional structure surrounding the Wnt acylation site. PORCN-mediated Wnt acylation was abolished when the Wnt peptide was treated with DTT, and did not occur with a linear (non-disulfide-bonded) peptide, or when the double disulfide-bonded Wnt peptide contained Ala substituted for the Ser acylation site. We exploited this in vitro Wnt acylation assay to provide direct evidence that the small molecule LGK974, which is in clinical trials for managing Wnt-driven tumors, is a bona fide PORCN inhibitor whose IC 50 for inhibition of Wnt fatty acylation in vitro closely matches that for inhibition of Wnt signaling. Side-by-side comparison of PORCN and Hedgehog acyltransferase (HHAT), two enzymes that attach 16-carbon fatty acids to secreted proteins, revealed that neither enzyme will accept the other's fatty acyl-CoA or peptide substrates. These findings illustrate the unique enzyme-substrate selectivity exhibited by members of the membrane-bound O -acyl transferase family. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. The Ewing sarcoma secretome and its response to activation of Wnt/beta-catenin signaling.

    Science.gov (United States)

    Hawkins, Allegra G; Basrur, Venkatesha; da Veiga Leprevost, Felipe; Pedersen, Elisabeth; Sperring, Colin; Nesvizhskii, Alexey I; Lawlor, Elizabeth R

    2018-01-31

    Tumor: tumor microenvironment (TME) interactions are critical for tumor progression and the composition and structure of the local extracellular matrix (ECM) are key determinants of tumor metastasis. We recently reported that activation of Wnt/beta-catenin signaling in Ewing sarcoma cells induces widespread transcriptional changes that are associated with acquisition of a metastatic tumor phenotype. Significantly, ECM protein-encoding genes were found to be enriched among Wnt/beta-catenin induced transcripts, leading us to hypothesize that activation of canonical Wnt signaling might induce changes in the Ewing sarcoma secretome. To address this hypothesis, conditioned media from Ewing sarcoma cell lines cultured in the presence or absence of Wnt3a was collected for proteomic analysis. Label-free mass spectrometry was used to identify and quantify differentially secreted proteins. We then used in silico databases to identify only proteins annotated as secreted. Comparison of the secretomes of two Ewing sarcoma cell lines revealed numerous shared proteins, as well as a degree of heterogeneity, in both basal and Wnt-stimulated conditions. Gene set enrichment analysis of secreted proteins revealed that Wnt stimulation reproducibly resulted in increased secretion of proteins involved in ECM organization, ECM receptor interactions, and collagen formation. In particular, Wnt-stimulated Ewing sarcoma cells upregulated secretion of structural collagens, as well as matricellular proteins, such as the metastasis-associated protein, tenascin C (TNC). Interrogation of published databases confirmed reproducible correlations between Wnt/beta-catenin activation and TNC and COL1A1 expression in patient tumors. In summary, this first study of the Ewing sarcoma secretome reveals that Wnt/beta-catenin activated tumor cells upregulate secretion of ECM proteins. Such Wnt/beta-catenin mediated changes are likely to impact on tumor: TME interactions that contribute to metastatic

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

    International Nuclear Information System (INIS)

    Railo, Antti; Pajunen, Antti; Itaeranta, Petri; Naillat, Florence; Vuoristo, Jussi; Kilpelaeinen, Pekka; Vainio, Seppo

    2009-01-01

    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-β-catenin immunoprecipitation of DNA-protein complexes from mouse NIH3T3 fibroblasts expressing a fusion protein of β-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.

  8. Wnt signaling in the early sea urchin embryo.

    Science.gov (United States)

    Kumburegama, Shalika; Wikramanayake, Athula H

    2008-01-01

    Wnt signaling regulates a remarkably diverse array of cellular and developmental events during animal embryogenesis and homeostasis. The crucial role that Wnt signaling plays in regulating axial patterning in early embryos has been particularly striking. Recent work has highlighted the conserved role that canonical Wnt signaling plays in patterning the animal-vegetal (A-V) axis in sea urchin and sea anemone embryos. In sea urchin embryos, the canonical Wnt signaling pathway is selectively turned on in vegetal cells as early as the 16-cell stage embryo, and signaling through this pathway is required for activation of the endomesodermal gene regulatory network. Loss of nuclear beta-catenin signaling animalizes the sea urchin embryo and blocks pattern formation along the entire A-V axis. Nuclear entry of beta-catenin into vegetal cells is regulated cell autonomously by maternal information that is present at the vegetal pole of the unfertilized egg. Analysis of Dishevelled (Dsh) regulation along the A-V axis has revealed the presence of a cytoarchitectural domain at the vegetal pole of the unfertilized sea urchin egg. This vegetal cortical domain appears to be crucial for the localized activation of Dsh at the vegetal pole, but the precise mechanisms are unknown. The elucidation of how Dsh is selectively activated at the vegetal cortical domain is likely to provide important insight into how this enigmatic protein is regulated during canonical Wnt signaling. Additionally, this information will shed light on the origins of embryonic polarity during animal evolution. This chapter examines the roles played by the canonical Wnt signaling pathway in the specification and patterning of the A-V axis in the sea urchin. These studies have led to the identification of a novel role for canonical Wnt signaling in regulating protein stability, and continued studies of Wnt signaling in this model system are likely to reveal additional roles for this pathway in regulating early

  9. Targeting Wnt Pathways in Disease

    Science.gov (United States)

    Zimmerman, Zachary F.; Moon, Randall T.

    2012-01-01

    Wnt-mediated signal transduction pathways have long been recognized for their roles in regulating embryonic development, and have more recently been linked to cancer, neurologic diseases, inflammatory diseases, and disorders of endocrine function and bone metabolism in adults. Although therapies targeting Wnt signaling are attractive in theory, in practice it has been difficult to obtain specific therapeutics because many components of Wnt signaling pathways are also involved in other cellular processes, thereby reducing the specificity of candidate therapeutics. New technologies, and advances in understanding the mechanisms of Wnt signaling, have improved our understanding of the nuances of Wnt signaling and are leading to promising new strategies to target Wnt signaling pathways. PMID:23001988

  10. Protein recognition by a pattern-generating fluorescent molecular probe

    Science.gov (United States)

    Pode, Zohar; Peri-Naor, Ronny; Georgeson, Joseph M.; Ilani, Tal; Kiss, Vladimir; Unger, Tamar; Markus, Barak; Barr, Haim M.; Motiei, Leila; Margulies, David

    2017-12-01

    Fluorescent molecular probes have become valuable tools in protein research; however, the current methods for using these probes are less suitable for analysing specific populations of proteins in their native environment. In this study, we address this gap by developing a unimolecular fluorescent probe that combines the properties of small-molecule-based probes and cross-reactive sensor arrays (the so-called chemical 'noses/tongues'). On the one hand, the probe can detect different proteins by generating unique identification (ID) patterns, akin to cross-reactive arrays. On the other hand, its unimolecular scaffold and selective binding enable this ID-generating probe to identify combinations of specific protein families within complex mixtures and to discriminate among isoforms in living cells, where macroscopic arrays cannot access. The ability to recycle the molecular device and use it to track several binding interactions simultaneously further demonstrates how this approach could expand the fluorescent toolbox currently used to detect and image proteins.

  11. Generation and propagation of radical reactions on proteins

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    2001-01-01

    The oxidation of proteins by free radicals is thought to play a major role in many oxidative processes within cells and is implicated in a number of human diseases as well as ageing. This review summarises information on the formation of radicals on peptides and proteins and how radical damage may...... be propagated and transferred within protein structures. The emphasis of this article is primarily on the deleterious actions of radicals generated on proteins, and their mechanisms of action, rather than on enzymatic systems where radicals are deliberately formed as transient intermediates. The final section...

  12. Wnt5a Promotes Inflammatory Responses via Nuclear Factor κB (NF-κB) and Mitogen-activated Protein Kinase (MAPK) Pathways in Human Dental Pulp Cells*

    Science.gov (United States)

    Zhao, Yuan; Wang, Chen-Lin; Li, Rui-Min; Hui, Tian-Qian; Su, Ying-Ying; Yuan, Quan; Zhou, Xue-Dong; Ye, Ling

    2014-01-01

    Wnt5a has been found recently to be involved in inflammation regulation through a mechanism that remains unclear. Immunohistochemical staining of infected human dental pulp and tissue from experimental dental pulpitis in rats showed that Wnt5a levels were increased. In vitro, Wnt5a was increased 8-fold in human dental pulp cells (HDPCs) after TNF-α stimulation compared with control cells. We then investigated the role of Wnt5a in HDPCs. In the presence of TNF-α, Wnt5a further increased the production of cytokines/chemokines, whereas Wnt5a knockdown markedly reduced cytokine/chemokine production induced by TNF-α. In addition, in HDPCs, Wnt5a efficiently induced cytokine/chemokine expression and, in particular, expression of IL-8 (14.5-fold) and CCL2 (25.5-fold), as assessed by a Luminex assay. The cytokine subsets regulated by Wnt5a overlap partially with those induced by TNF-α. However, no TNF-α and IL-1β was detected after Wnt5a treatment. We then found that Wnt5a alone and the supernatants of Wnt5a-treated HDPCs significantly increased macrophage migration, which supports a role for Wnt5a in macrophage recruitment and as an inflammatory mediator in human dental pulp inflammation. Finally, Wnt5a participates in dental pulp inflammation in a MAPK-dependent (p38-, JNK-, and ERK-dependent) and NF-κB-dependent manner. Our data suggest that Wnt5a, as an inflammatory mediator that drives the integration of cytokines and chemokines, acts downstream of TNF-α. PMID:24891513

  13. 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.

  14. Effects of Wnt3a on proliferation and differentiation of human epidermal stem cells

    International Nuclear Information System (INIS)

    Jia Liwei; Zhou Jiaxi; Peng Sha; Li Juxue; Cao Yujing; Duan Enkui

    2008-01-01

    Epidermal stem cells maintain development and homeostasis of mammalian epidermis throughout life. However, the molecular mechanisms involved in the proliferation and differentiation of epidermal stem cells are far from clear. In this study, we investigated the effects of Wnt3a and Wnt/β-catenin signaling on proliferation and differentiation of human fetal epidermal stem cells. We found both Wnt3a and active β-catenin, two key members of the Wnt/β-catenin signaling, were expressed in human fetal epidermis and epidermal stem cells. In addition, Wnt3a protein can promote proliferation and inhibit differentiation of epidermal stem cells in vitro culture. Our results suggest that Wnt/β-catenin signaling plays important roles in human fetal skin development and homeostasis, which also provide new insights on the molecular mechanisms of oncogenesis in human epidermis

  15. Kinetics of Wnt-driven beta-catenin stabilization revealed by quantitative and temporal imaging.

    Directory of Open Access Journals (Sweden)

    Rami N Hannoush

    Full Text Available The Wnt/beta-catenin signal transduction pathway regulates a broad range of developmental processes. Aberrant activation of the Wnt pathway leads to cancer and degenerative diseases. beta-catenin is a key signaling molecule that is frequently used as a direct monitor of Wnt pathway activation. This paper describes a multi-parametric method for quantitative analysis of cellular beta-catenin protein levels in a rapid and high-throughput manner. The assay offers temporally resolved detection of Wnt-stimulated accumulation of beta-catenin, simultaneously detecting cell number, and it sheds light onto the kinetics of posttranslational stabilization of beta-catenin.

  16. WNT5A inhibits metastasis and alters splicing of Cd44 in breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Wen Jiang

    Full Text Available Wnt5a is a non-canonical signaling Wnt. Low expression of WNT5A is correlated with poor prognosis in breast cancer patients. The highly invasive breast cancer cell lines, MDA-MB-231 and 4T1, express very low levels of WNT5A. To determine if enhanced expression of WNT5A would affect metastatic behavior, we generated WNT5A expressing cells from the 4T1 and MDA-MB-231 parental cell lines. WNT5A expressing cells demonstrated cobblestone morphology and reduced in vitro migration relative to controls. Cell growth was not altered. Metastasis to the lung via tail vein injection was reduced in the 4T1-WNT5A expressing cells relative to 4T1-vector controls. To determine the mechanism of WNT5A action on metastasis, we performed microarray and whole-transcriptome sequence analysis (RNA-seq to compare gene expression in 4T1-WNT5A and 4T1-vector cells. Analysis indicated highly significant alterations in expression of genes associated with cellular movement. Down-regulation of a subset of these genes, Mmp13, Nos2, Il1a, Cxcl2, and Lamb3, in WNT5A expressing cells was verified by semi-quantitative RT-PCR. Significant differences in transcript splicing were also detected in cell movement associated genes including Cd44. Cd44 is an adhesion molecule with a complex genome structure. Variable exon usage is associated with metastatic phenotype. Alternative spicing of Cd44 in WNT5A expressing cells was confirmed using RT-PCR. We conclude that WNT5A inhibits metastasis through down-regulation of multiple cell movement pathways by regulating transcript levels and splicing of key genes like Cd44.

  17. Spatio-temporal expression patterns of Wnt signaling pathway during the development of temporomandibular condylar cartilage.

    Science.gov (United States)

    Chen, Kan; Quan, Huixin; Chen, Gang; Xiao, Di

    2017-11-01

    There is a growing body of evidence supporting the involvement of the Wnt signaling pathway in various aspects of skeletal and joint development; however, it is unclear whether it is involved in the process of temporomandibular joint development. In order to clarify this issue, we examined the spatio-temporal distribution of mRNAs and proteins of the Wnt family during the formation of the mandibular condylar cartilage at the prenatal and postnatal stages. An in situ hybridization test revealed no mRNAs of β-catenin and Axin2 during early mesenchymal condensation; the ligands surveyed in this study (including Wnt-4, 5a, and 9a) were clearly detected at various ranges of expression, mainly in the condylar blastema and later distinct cartilaginous layers. Apart from β-catenin and Axin2, the Wnt family members surveyed in this study, including Lef-1, were found to be immunopositive during early chondrogenesis in the condylar cartilage at E14.5. After distinct chondrocyte layers were identified within the cartilage at E16.5, the expression of the Wnt signaling members was different and mainly restricted to proliferating cells and mineralized hypertrophic chondrocytes. In the adult mandibular condylar cartilage, the Wnt-4 mRNA, as well as the Wnt-4 and Wnt-9a proteins, was not observed. Our findings demonstrated that the Wnt signaling pathway was associated with the development of mandibular condylar cartilage. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Blocking Wnt5a signaling decreases CD36 expression and foam cell formation in atherosclerosis.

    Science.gov (United States)

    Ackers, Ian; Szymanski, Candice; Duckett, K Jordan; Consitt, Leslie A; Silver, Mitchell J; Malgor, Ramiro

    2018-02-20

    Wnt5a is a highly studied member of the Wnt family and recently has been implicated in the pathogenesis of atherosclerosis, but its precise role is unknown. Foam cell development is a critical process to atherosclerotic plaque formation. In the present study, we investigated the role of noncanonical Wnt5a signaling in the development of foam cells. Human carotid atherosclerotic tissue and THP-1-derived macrophages were used to investigate the contribution of Wnt5a signaling in the formation of foam cells. Immunohistochemistry was used to evaluate protein expression of scavenger receptors and noncanonical Wnt5a receptors [frizzled 5 (Fz5) and receptor tyrosine kinase-like orphan receptor 2 (Ror2)] in human atherosclerotic macrophages/foam cells. Changes in protein expression in response to Wnt5a stimulation/inhibition were determined by Western blot, and lipid accumulation was evaluated by fluorescent lipid droplet staining. Wnt5a (Pfoam cells within the plaque. In vitro studies revealed that Wnt5a significantly increased the expression of the lipid uptake receptor CD36 (P.05). rWnt5a also significantly increased lipid accumulation in THP-1 macrophages (Pfoam cells. Copyright © 2018. Published by Elsevier Inc.

  19. Wnt1 Participates in Inflammation Induced by Lipopolysaccharide Through Upregulating Scavenger Receptor A and NF-kB.

    Science.gov (United States)

    Zhao, Wenting; Sun, Zewei; Wang, Shuai; Li, Zhenwei; Zheng, Liangrong

    2015-08-01

    The study investigated the role of wnt1 in the inflammatory response initiated by lipolysaccharide (LPS), and analyzed the association between wnt1, NF-KB, and inflammatory factors. THP-1 cells were activated with phorbol-12-myristate-13-acetate (PMA) and treated with LPS to induce inflammation. THP-1 cells were transfected with wnt1siRNA and overexpression plasmid to explore the relationship among wnt1, SRA, and NF-KB. Inhibitor of β-catenin and siRNA of FZD1were used to investigate the signaling events involved in SRA activation induced by wnt1. Levels of NF-kB protein and inflammatory cytokines were assessed followingwnt1 siRNA and LPS treatment. PMA activation and LPS treatment of THP-1 cells increased wnt1 protein levels. Wnt1 promoted SRA expression through activation of canonical wnt pathway. Wnt1 increased NF-kB protein levels and enhanced the secretion of IL-6, TNF-α, and iNOS through binding to SRA. These findings suggest that wnt1 increased SRA and NF-kB protein levels and participated in the inflammatory response.

  20. Rapamycin delays growth of Wnt-1 tumors in spite of suppression of host immunity

    International Nuclear Information System (INIS)

    Svirshchevskaya, Elena V; Mariotti, Jacopo; Wright, Mollie H; Viskova, Natalia Y; Telford, William; Fowler, Daniel H; Varticovski, Lyuba

    2008-01-01

    Rapamycin, an inhibitor of mammalian target of Rapamycin (mTOR), is an immunosuppressive agent that has anti-proliferative effects on some tumors. However, the role of Rapamycin-induced immune suppression on tumor progression has not been examined. We developed a transplantation model for generation of mammary tumors in syngeneic recipients that can be used to address the role of the immune system on tumor progression. We examined the effect of Rapamycin on the immune system and growth of MMTV-driven Wnt-1 mammary tumors which were transplanted into irradiated and bone marrow-reconstituted, or naïve mice. Rapamycin induced severe immunosuppression and significantly delayed the growth of Wnt-1 tumors. T cell depletion in spleen and thymus and reduction in T cell cytokine secretion were evident within 7 days of therapy. By day 20, splenic but not thymic T cell counts, and cytokine secretion recovered. We determined whether adoptive T cell therapy enhances the anti-cancer effect using ex vivo generated Rapamycin-resistant T cells. However, T cell transfer during Rapamycin therapy did not improve the outcome relative to drug therapy alone. Thus, we could not confirm that suppression of T cell immunity contributes to tumor growth in this model. Consistent with suppression of the mTOR pathway, decreased 4E-BP1, p70 S6-kinase, and S6 protein phosphorylation correlated with a decrease in Wnt-1 tumor cell proliferation. Rapamycin has a direct anti-tumor effect on Wnt-1 breast cancer in vivo that involves inhibition of the mTOR pathway at doses that also suppress host immune responses

  1. Wnt and lithium: a common destiny in the therapy of nervous system pathologies?

    Science.gov (United States)

    Meffre, Delphine; Grenier, Julien; Bernard, Sophie; Courtin, Françoise; Dudev, Todor; Shackleford, Ghjuvan'Ghjacumu; Jafarian-Tehrani, Mehrnaz; Massaad, Charbel

    2014-04-01

    Wnt signaling is required for neurogenesis, the fate of neural progenitors, the formation of neuronal circuits during development, neuron positioning and polarization, axon and dendrite development and finally for synaptogenesis. This signaling pathway is also implicated in the generation and differentiation of glial cells. In this review, we describe the mechanisms of action of Wnt signaling pathways and their implication in the development and correct functioning of the nervous system. We also illustrate how a dysregulated Wnt pathway could lead to psychiatric, neurodegenerative and demyelinating pathologies. Lithium, used for the treatment of bipolar disease, inhibits GSK3β, a central enzyme of the Wnt/β-catenin pathway. Thus, lithium could, to some extent, mimic Wnt pathway. We highlight the possible dialogue between lithium therapy and modulation of Wnt pathway in the treatment of the diseases of the nervous system.

  2. Activation of intracellular calcium by multiple Wnt ligands and translocation of β-catenin into the nucleus: a convergent model of Wnt/Ca2+ and Wnt/β-catenin pathways.

    Science.gov (United States)

    Thrasivoulou, Christopher; Millar, Michael; Ahmed, Aamir

    2013-12-13

    Ca(2+) and β-catenin, a 92-kDa negatively charged transcription factor, transduce Wnt signaling via the non-canonical, Wnt/Ca(2+) and canonical, Wnt/β-catenin pathways independently. The nuclear envelope is a barrier to large protein entry, and this process is regulated by intracellular calcium [Ca(2+)]i and trans-nuclear potential. How β-catenin traverses the nuclear envelope is not well known. We hypothesized that Wnt/Ca(2+) and Wnt/β-catenin pathways act in a coordinated manner and that [Ca(2+)]i release facilitates β-catenin entry into the nucleus in mammalian cells. In a live assay using calcium dyes in PC3 prostate cancer cells, six Wnt peptides (3A, 4, 5A, 7A, 9B, and 10B) mobilized [Ca(2+)]i but Wnt11 did not. Based upon dwell time (range = 15-30 s) of the calcium waveform, these Wnts could be classified into three classes: short, 3A and 5A; long, 7A and 10B; and very long, 4 and 9B. Wnt-activated [Ca(2+)]i release was followed by an increase in intranuclear calcium and the depolarization of both the cell and nuclear membranes, determined by using FM4-64. In cells treated with Wnts 5A, 9B, and 10B, paradigm substrates for each Wnt class, increased [Ca(2+)]i was followed by β-catenin translocation into the nucleus in PC3, MCF7, and 253J, prostate, breast, and bladder cancer cell lines; both the increase in Wnt 5A, 9B, and 10B induced [Ca(2+)]i release and β-catenin translocation are suppressed by thapsigargin in PC3 cell line. We propose a convergent model of Wnt signaling network where Ca(2+) and β-catenin pathways may act in a coordinated, interdependent, rather than independent, manner.

  3. Wnt/β-catenin Inhibits Dental Pulp Stem Cell Differentiation

    Science.gov (United States)

    Scheller, E.L.; Chang, J.; Wang, C.Y.

    2010-01-01

    Dental pulp stem cells (DPSCs) are a unique precursor population isolated from post-natal human dental pulp and have the ability to regenerate a reparative dentin-like complex. Canonical Wnt signaling plays a critical role in tooth development and stem cell self-renewal through β-catenin. In this study, the regulation of odontoblast-like differentiation of DPSCs by canonical Wnt signaling was examined. DPSCs were stably transduced with canonical Wnt-1 or the active form of β-catenin, with retrovirus-mediated infection. Northern blot analysis found that Wnt-1 strongly induced the expression of matricellular protein osteopontin, and modestly enhanced the expression of type I collagen in DPSCs. Unexpectedly, Wnt-1 inhibited alkaline phosphatase (ALP) activity and the formation of mineralized nodules in DPSCs. Moreover, over-expression of β-catenin was also sufficient to suppress the differentiation and mineralization of DPSCs. In conclusion, our results suggest that canonical Wnt signaling negatively regulates the odontoblast-like differentiation of DPSCs. PMID:18218837

  4. Frequent epigenetic inactivation of Wnt antagonist genes in breast cancer

    Science.gov (United States)

    Suzuki, H; Toyota, M; Caraway, H; Gabrielson, E; Ohmura, T; Fujikane, T; Nishikawa, N; Sogabe, Y; Nojima, M; Sonoda, T; Mori, M; Hirata, K; Imai, K; Shinomura, Y; Baylin, S B; Tokino, T

    2008-01-01

    Although mutation of APC or CTNNB1 (β-catenin) is rare in breast cancer, activation of Wnt signalling is nonetheless thought to play an important role in breast tumorigenesis, and epigenetic silencing of Wnt antagonist genes, including the secreted frizzled-related protein (SFRP) and Dickkopf (DKK) families, has been observed in various tumours. In breast cancer, frequent methylation and silencing of SFRP1 was recently documented; however, altered expression of other Wnt antagonist genes is largely unknown. In the present study, we found frequent methylation of SFRP family genes in breast cancer cell lines (SFRP1, 7 out of 11, 64%; SFRP2, 11 out of 11, 100%; SFRP5, 10 out of 11, 91%) and primary breast tumours (SFRP1, 31 out of 78, 40%; SFRP2, 60 out of 78, 77%; SFRP5, 55 out of 78, 71%). We also observed methylation of DKK1, although less frequently, in cell lines (3 out of 11, 27%) and primary tumours (15 out of 78, 19%). Breast cancer cell lines express various Wnt ligands, and overexpression of SFRPs inhibited cancer cell growth. In addition, overexpression of a β-catenin mutant and depletion of SFRP1 using small interfering RNA synergistically upregulated transcriptional activity of T-cell factor/lymphocyte enhancer factor. Our results confirm the frequent methylation and silencing of Wnt antagonist genes in breast cancer, and suggest that their loss of function contributes to activation of Wnt signalling in breast carcinogenesis. PMID:18283316

  5. Cell intrinsic modulation of Wnt signaling controls neuroblast migration in C. elegans

    NARCIS (Netherlands)

    Mentink, Remco A; Middelkoop, Teije C; Rella, Lorenzo; Ji, Ni; Tang, Chung Yin; Betist, Marco C; van Oudenaarden, Alexander; Korswagen, Hendrik C

    2014-01-01

    Members of the Wnt family of secreted signaling proteins are key regulators of cell migration and axon guidance. In the nematode C. elegans, the migration of the QR neuroblast descendants requires multiple Wnt ligands and receptors. We found that the migration of the QR descendants is divided into

  6. Canonical WNT signalling controls hair follicle spacing.

    Science.gov (United States)

    Schlake, Thomas; Sick, Stefanie

    2007-01-01

    Canonical WNT signals play an important role in hair follicle development. In addition to being crucial for epidermal appendage initiation, they control the interfollicular spacing pattern and contribute to the spatial orientation and largely parallel alignment of hair follicles. However, owing to the complexity of canonical WNT signalling and its interconnections with other pathways, many details of hair follicle formation await further clarification. Here, we discuss the recently suggested reaction-diffusion (RD) mechanism of spatial hair follicle arrangement in the light of yet unpublished data and conclusions. They clearly demonstrate that the observed hair follicle clustering in dickkopf (DKK) transgenic mice cannot be explained by any trivial process caused by protein overexpression, thereby further supporting our model of hair follicle spacing. Furthermore, we suggest future experiments to challenge the RD model of spatial follicle arrangement.

  7. Mapping of Wnt-Frizzled interactions by multiplex CRISPR targeting of receptor gene families.

    Science.gov (United States)

    Voloshanenko, Oksana; Gmach, Philipp; Winter, Jan; Kranz, Dominique; Boutros, Michael

    2017-11-01

    Signaling pathway modules are often encoded by several closely related paralogous genes that can have redundant roles and are therefore difficult to analyze by loss-of-function analysis. A typical example is the Wnt signaling pathway, which in mammals is mediated by 19 Wnt ligands that can bind to 10 Frizzled (FZD) receptors. Although significant progress in understanding Wnt-FZD receptor interactions has been made in recent years, tools to generate systematic interaction maps have been largely lacking. Here we generated cell lines with multiplex mutant alleles of FZD1 , FZD2 , and FZD7 and demonstrate that these cells are unresponsive to canonical Wnt ligands. Subsequently, we performed genetic rescue experiments with combinations of FZDs and canonical Wnts to create a functional ligand-receptor interaction map. These experiments showed that whereas several Wnt ligands, such as Wnt3a, induce signaling through a broad spectrum of FZD receptors, others, such as Wnt8a, act through a restricted set of FZD genes. Together, our results map functional interactions of FZDs and 10 Wnt ligands and demonstrate how multiplex targeting by clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 can be used to systematically elucidate the functions of multigene families.-Voloshanenko, O., Gmach, P., Winter, J., Kranz, D., Boutros, M. Mapping of Wnt-Frizzled interactions by multiplex CRISPR targeting of receptor gene families. © The Author(s).

  8. Generation of Fluorescent Protein Fusions in Candida Species.

    Science.gov (United States)

    Gonia, Sara; Berman, Judith; Gale, Cheryl A

    2017-03-04

    Candida species, prevalent colonizers of the intestinal and genitourinary tracts, are the cause of the majority of invasive fungal infections in humans. Thus, molecular and genetic tools are needed to facilitate the study of their pathogenesis mechanisms. PCR-mediated gene modification is a straightforward and quick approach to generate epitope-tagged proteins to facilitate their detection. In particular, fluorescent protein (FP) fusions are powerful tools that allow visualization and quantitation of both yeast cells and proteins by fluorescence microscopy and immunoblotting, respectively. Plasmids containing FP encoding sequences, along with nutritional marker genes that facilitate the transformation of Candida species, have been generated for the purpose of FP construction and expression in Candida. Herein, we present a strategy for constructing a FP fusion in a Candida species. Plasmids containing the nourseothricin resistance transformation marker gene (NAT1) along with sequences for either green, yellow, or cherry FPs (GFP, YFP, mCherry) are used along with primers that include gene-specific sequences in a polymerase chain reaction (PCR) to generate a FP cassette. This gene-specific cassette has the ability to integrate into the 3'-end of the corresponding gene locus via homologous recombination. Successful in-frame fusion of the FP sequence into the gene locus of interest is verified genetically, followed by analysis of fusion protein expression by microscopy and/or immuno-detection methods. In addition, for the case of highly expressed proteins, successful fusions can be screened for primarily by fluorescence imaging techniques.

  9. A generative, probabilistic model of local protein structure

    DEFF Research Database (Denmark)

    Boomsma, Wouter; Mardia, Kanti V.; Taylor, Charles C.

    2008-01-01

    conformational stabilities. Here, we present a fully probabilistic, continuous model of local protein structure in atomic detail. The generative model makes efficient conformational sampling possible and provides a framework for the rigorous analysis of local sequence-structure correlations in the native state...

  10. Inhibition of adipocytogenesis by canonical WNT signaling in human mesenchymal stem cells

    International Nuclear Information System (INIS)

    Shen, Longxiang; Glowacki, Julie; Zhou, Shuanhu

    2011-01-01

    The WNT signaling pathway plays important roles in the self-renewal and differentiation of mesenchymal stem cells (MSCs). Little is known about WNT signaling in adipocyte differentiation of human MSCs. In this study, we tested the hypothesis that canonical and non-canonical WNTs differentially regulate in vitro adipocytogenesis in human MSCs. The expression of adipocyte gene PPARγ2, lipoprotein lipase, and adipsin increased during adipocytogenesis of hMSCs. Simultaneously, the expression of canonical WNT2, 10B, 13, and 14 decreased, whereas non-canonical WNT4 and 11 increased, and WNT5A was unchanged. A small molecule WNT mimetic, SB-216763, increased accumulation of β-catenin protein, inhibited induction of WNT4 and 11 and inhibited adipocytogenesis. In contrast, knockdown of β-catenin with siRNA resulted in spontaneous adipocytogenesis. These findings support the view that canonical WNT signaling inhibits and non-canonical WNT signaling promotes adipocytogenesis in adult human marrow-derived mesenchymal stem cells.

  11. Normal mode-guided transition pathway generation in proteins.

    Directory of Open Access Journals (Sweden)

    Byung Ho Lee

    Full Text Available The biological function of proteins is closely related to its structural motion. For instance, structurally misfolded proteins do not function properly. Although we are able to experimentally obtain structural information on proteins, it is still challenging to capture their dynamics, such as transition processes. Therefore, we need a simulation method to predict the transition pathways of a protein in order to understand and study large functional deformations. Here, we present a new simulation method called normal mode-guided elastic network interpolation (NGENI that performs normal modes analysis iteratively to predict transition pathways of proteins. To be more specific, NGENI obtains displacement vectors that determine intermediate structures by interpolating the distance between two end-point conformations, similar to a morphing method called elastic network interpolation. However, the displacement vector is regarded as a linear combination of the normal mode vectors of each intermediate structure, in order to enhance the physical sense of the proposed pathways. As a result, we can generate more reasonable transition pathways geometrically and thermodynamically. By using not only all normal modes, but also in part using only the lowest normal modes, NGENI can still generate reasonable pathways for large deformations in proteins. This study shows that global protein transitions are dominated by collective motion, which means that a few lowest normal modes play an important role in this process. NGENI has considerable merit in terms of computational cost because it is possible to generate transition pathways by partial degrees of freedom, while conventional methods are not capable of this.

  12. Bisphenol-A Mediated Inhibition of Hippocampal Neurogenesis Attenuated by Curcumin via Canonical Wnt Pathway.

    Science.gov (United States)

    Tiwari, Shashi Kant; Agarwal, Swati; Tripathi, Anurag; Chaturvedi, Rajnish Kumar

    2016-07-01

    Bisphenol A (BPA) is an environmental xenoestrogenic endocrine disruptor, utilized for production of consumer products, and exerts adverse effects on the developing nervous system. Recently, we found that BPA impairs the finely tuned dynamic processes of neurogenesis (generation of new neurons) in the hippocampus of the developing rat brain. Curcumin is a natural polyphenolic compound, which provides neuroprotection against various environmental neurotoxicants and in the cellular and animal models of neurodegenerative disorders. Here, we have assessed the neuroprotective efficacy of curcumin against BPA-mediated reduced neurogenesis and the underlying cellular and molecular mechanism(s). Both in vitro and in vivo studies showed that curcumin protects against BPA-induced hippocampal neurotoxicity. Curcumin protects against BPA-mediated reduced neural stem cells (NSC) proliferation and neuronal differentiation and enhanced neurodegeneration. Curcumin also enhances the expression/levels of neurogenic and the Wnt pathway genes/proteins, which were reduced due to BPA exposure in the hippocampus. Curcumin-mediated neuroprotection against BPA-induced neurotoxicity involved activation of the Wnt/β-catenin signaling pathway, which was confirmed by the use of Wnt specific activators (LiCl and GSK-3β siRNA) and inhibitor (Dkk-1). BPA-mediated increased β-catenin phosphorylation, decreased GSK-3β levels, and β-catenin nuclear translocation were significantly reversed by curcumin, leading to enhanced neurogenesis. Curcumin-induced protective effects on neurogenesis were blocked by Dkk-1 in NSC culture treated with BPA. Curcumin-mediated enhanced neurogenesis was correlated well with improved learning and memory in BPA-treated rats. Overall, our results conclude that curcumin provides neuroprotection against BPA-mediated impaired neurogenesis via activation of the Wnt/β-catenin signaling pathway.

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

    Directory of Open Access Journals (Sweden)

    Polloneal Jymmiel R Ocbina

    2009-08-01

    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.

  14. Enhanced expression of Wnt9a in the flexor tenosynovium in idiopathic carpal tunnel syndrome.

    Science.gov (United States)

    Yamanaka, Yoshiaki; Menuki, Kunitaka; Zenke, Yukichi; Hirasawa, Hideyuki; Sakai, Akinori

    2015-10-01

    This study aimed to clarify the association between abnormal Wnt signaling and the cause of idiopathic carpal tunnel syndrome (ICTS) and whether an association exists between Wnt signaling and cell proliferation in the flexor tenosynovium. The subjects included nine patients with ICTS; the controls were nine patients with distal radius fractures without any symptoms of carpal tunnel syndrome. We extracted mRNA from the flexor tenosynovium and compared the expression levels of genes encoding 17 types of Wnt in both subjects and controls via quantitative real-time polymerase chain reaction (PCR). Expression levels of factors involved in cell proliferation, such as estrogen-responsive finger protein, epidermal growth factor receptor, heparin binding-epidermal growth factor-like growth factor, insulin-like growth factor-1, and vascular endothelial growth factor (VEGF) were also measured using quantitative real-time PCR. In addition, we compared the Wnt and MIB-1 protein expression levels to clarify the effect of Wnt on cell proliferation. Quantitative real-time PCR revealed significantly greater expression of the gene encoding Wnt9a in subjects with ICTS than in controls and also revealed a positive correlation between the expression of genes encoding Wnt9a and VEGF in subjects with ICTS. Quantitative evaluation using immunohistochemical staining also indicated more marked Wnt9a expression in subjects than in controls. However, there was no relationship between the expression of Wnt9a and the cell proliferation index MIB-1. These results indicate that Wnt9a expression is enhanced in ICTS and that Wnt9a may be involved in VEGF expression in ICTS. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  15. Non-canonical Wnt signaling through Wnt5a/b and a novel Wnt11 gene, Wnt11b, regulates cell migration during avian gastrulation

    OpenAIRE

    Hardy, Katharine M.; Garriock, Robert J.; Yatskievych, Tatiana A.; D'Agostino, Susan L.; Antin, Parker B.; Krieg, Paul A.

    2008-01-01

    Knowledge of the molecular mechanisms regulating cell ingression, epithelial-mesenchymal transition and migration movements during amniote gastrulation is steadily improving. In the frog and fish embryo, Wnt5 and Wnt11 ligands are expressed around the blastopore and play an important role in regulating cell movements associated with gastrulation. In the chicken embryo, although Wnt5a and Wnt5b are expressed in the primitive streak, the known Wnt11 gene is expressed in paraxial and intermediat...

  16. Fluorescent protein marker lines in maize: generation and applications.

    Science.gov (United States)

    Wu, Qingyu; Luo, Anding; Zadrozny, Tara; Sylvester, Anne; Jackson, Dave

    2013-01-01

    Fluorescent proteins (FP) have significantly impacted the way that we study plants in the past two decades. In the post-genomics era, these FP tools are in higher demand by plant scientists for studying the dynamics of protein localization, function, and interactions, and to translate sequence information to biological knowledge that can benefit humans. Although FP tools have been widely used in the model plant Arabidopsis, few FP resources have been developed for maize, one of the most important food crops worldwide, and an ideal species for genetic and developmental biology research. In an effort to provide the maize and cereals research communities with a comprehensive set of FP resources for different purposes of study, we generated more than 100 stable transformed maize FP marker lines, which mark most compartments in maize cells with different FPs. Additionally, we are generating driver and reporter lines, based on the principle of the pOp-LhG4 transactivation system, allowing specific expression or mis-expression of any gene of interest to precisely study protein functions. These marker lines can be used not only for static protein localization studies, but will be useful for studying protein dynamics and interactions using kinetic microscopy methods, such as fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS), and fluorescence resonance energy transfer (FRET).

  17. Wnt5a Regulates the Assembly of Human Adipose Derived Stromal Vascular Fraction-Derived Microvasculatures.

    Directory of Open Access Journals (Sweden)

    Venkat M Ramakrishnan

    Full Text Available Human adipose-derived stromal vascular fraction (hSVF cells are an easily accessible, heterogeneous cell system that can spontaneously self-assemble into functional microvasculatures in vivo. However, the mechanisms underlying vascular self-assembly and maturation are poorly understood, therefore we utilized an in vitro model to identify potential in vivo regulatory mechanisms. We utilized passage one (P1 hSVF because of the rapid UEA1+ endothelium (EC loss at even P2 culture. We exposed hSVF cells to a battery of angiogenesis inhibitors and found that the pan-Wnt inhibitor IWP2 produced the most significant hSVF-EC networking decrease (~25%. To determine which Wnt isoform(s and receptor(s may be involved, hSVF was screened by PCR for isoforms associated with angiogenesis, with only WNT5A and its receptor, FZD4, being expressed for all time points observed. Immunocytochemistry confirmed Wnt5a protein expression by hSVF. To see if Wnt5a alone could restore IWP2-induced EC network inhibition, recombinant human Wnt5a (0-150 ng/ml was added to IWP2-treated cultures. The addition of rhWnt5a significantly increased EC network area and significantly decreased the ratio of total EC network length to EC network area compared to untreated controls. To determine if Wnt5a mediates in vivo microvascular self-assembly, 3D hSVF constructs containing an IgG isotype control, anti-Wnt5a neutralizing antibody or rhWnt5a were implanted subcutaneously for 2w in immune compromised mice. Compared to IgG controls, anti-Wnt5a treatment significantly reduced vessel length density by ~41%, while rhWnt5a significantly increased vessel length density by ~62%. However, anti-Wnt5a or rhWnt5a did not significantly affect the density of segments and nodes, both of which measure vascular complexity. Taken together, this data demonstrates that endogenous Wnt5a produced by hSVF plays a regulatory role in microvascular self-assembly in vivo. These findings also suggest that

  18. 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.

  19. IL-1β-induced, matrix metalloproteinase-3-regulated proliferation of embryonic stem cell-derived odontoblastic cells is mediated by the Wnt5 signaling pathway

    International Nuclear Information System (INIS)

    Ozeki, Nobuaki; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki; Kawai, Rie; Kondo, Ayami; Nakata, Kazuhiko; Mogi, Makio

    2014-01-01

    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

  20. Interrelationship of canonical and non-canonical Wnt signalling pathways in chronic metabolic diseases.

    Science.gov (United States)

    Ackers, Ian; Malgor, Ramiro

    2018-01-01

    Chronic diseases account for approximately 45% of all deaths in developed countries and are particularly prevalent in countries with the most sophisticated and robust public health systems. Chronic metabolic diseases, specifically lifestyle-related diseases pertaining to diet and exercise, continue to be difficult to treat clinically. The most prevalent of these chronic metabolic diseases include obesity, diabetes, non-alcoholic fatty liver disease, chronic kidney disease and cardiovascular disease and will be the focus of this review. Wnt proteins are highly conserved glycoproteins best known for their role in development and homeostasis of tissues. Given the importance of Wnt signalling in homeostasis, aberrant Wnt signalling likely regulates metabolic processes and may contribute to the development of chronic metabolic diseases. Expression of Wnt proteins and dysfunctional Wnt signalling has been reported in multiple chronic diseases. It is interesting to speculate about an interrelationship between the Wnt signalling pathways as a potential pathological mechanism in chronic metabolic diseases. The aim of this review is to summarize reported findings on the contrasting roles of Wnt signalling in lifestyle-related chronic metabolic diseases; specifically, the contribution of Wnt signalling to lipid accumulation, fibrosis and chronic low-grade inflammation.

  1. Selective enhancement of wnt4 expression by cyclic AMP-associated cooperation between rat central astrocytes and microglia

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Masatoshi, E-mail: ohnishi@fupharm.fukuyama-u.ac.jp [Department of Pharmacotherapeutics, Graduate School of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Department of Pharmacotherapeutics, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Urasaki, Tomoka [Department of Pharmacotherapeutics, Graduate School of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Ochiai, Hiroyuki; Matsuoka, Kohei; Takeo, Shin; Harada, Tomoki; Ohsugi, Yoshihito [Department of Pharmacotherapeutics, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Inoue, Atsuko [Department of Pharmacotherapeutics, Graduate School of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan); Department of Pharmacotherapeutics, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985-1 Sanzo, Higashimura-cho, Fukuyama, Hiroshima, 729-0292 (Japan)

    2015-11-13

    The wnt protein family has important members involved in cell differentiation, proliferation and plasticity expression; however, little is known about its biosynthesis processes. On the other hand, an increase in the intracerebral cyclic adenosine 3′, 5’-monophosphate (cAMP) level leads to synaptic plasticity via the de novo synthesis of any protein. Here, the effect of dibutyryl cAMP (dbcAMP), a membrane permeability cAMP analog, on the wnt family was investigated in rat primary-cultured glial cells containing astrocytes and microglia. Among wnt3a, 4, 5a, 7a and 11 mRNA, only wnt4 expression was increased by longer treatment (24 h), compared with short treatment (2 h), with dbcAMP in a concentration-dependent manner, and its effect reached statistical significance at 1 mM. In cultures of isolated astrocytes or microglia, wnt4 expression was not affected by 1 mM dbcAMP for 24 h, and microglial wnt4 protein was undetectable even when cells were treated with the drug. Mixed glial cells treated for 24 h with 1 mM dbcAMP showed significantly increased wnt4 protein, as well as mRNA. Immunofluorescence manifested that cells that expressed wnt4 protein were astrocytes, but not microglia. Intraperitoneal injection of 1.25 mg/kg rolipram, a phosphodiesterase (PDE) IV inhibitor that can pass through the blood brain barrier and inhibits cAMP degradation specifically, showed a tendency to increase wnt4 expression in the adult rat brain after 24 h, and the increases in wnt4 mRNA and protein levels reached statistical significance in the hippocampus and striatum, respectively. This is the first finding to help elucidate the selective biosynthesis of central wnt4 through cAMP-stimulated microglia and astrocytes interaction. - Highlights: • Dibutyryl cAMP increased wnt4, but not wnt3a, 5a, 7a and 11, mRNA in mixed glia. • Wnt4 protein increased in astrocytes co-cultivated with microglia. • It took a long time to robustly increase wnt4 expression. • Rolipram

  2. Selective enhancement of wnt4 expression by cyclic AMP-associated cooperation between rat central astrocytes and microglia

    International Nuclear Information System (INIS)

    Ohnishi, Masatoshi; Urasaki, Tomoka; Ochiai, Hiroyuki; Matsuoka, Kohei; Takeo, Shin; Harada, Tomoki; Ohsugi, Yoshihito; Inoue, Atsuko

    2015-01-01

    The wnt protein family has important members involved in cell differentiation, proliferation and plasticity expression; however, little is known about its biosynthesis processes. On the other hand, an increase in the intracerebral cyclic adenosine 3′, 5’-monophosphate (cAMP) level leads to synaptic plasticity via the de novo synthesis of any protein. Here, the effect of dibutyryl cAMP (dbcAMP), a membrane permeability cAMP analog, on the wnt family was investigated in rat primary-cultured glial cells containing astrocytes and microglia. Among wnt3a, 4, 5a, 7a and 11 mRNA, only wnt4 expression was increased by longer treatment (24 h), compared with short treatment (2 h), with dbcAMP in a concentration-dependent manner, and its effect reached statistical significance at 1 mM. In cultures of isolated astrocytes or microglia, wnt4 expression was not affected by 1 mM dbcAMP for 24 h, and microglial wnt4 protein was undetectable even when cells were treated with the drug. Mixed glial cells treated for 24 h with 1 mM dbcAMP showed significantly increased wnt4 protein, as well as mRNA. Immunofluorescence manifested that cells that expressed wnt4 protein were astrocytes, but not microglia. Intraperitoneal injection of 1.25 mg/kg rolipram, a phosphodiesterase (PDE) IV inhibitor that can pass through the blood brain barrier and inhibits cAMP degradation specifically, showed a tendency to increase wnt4 expression in the adult rat brain after 24 h, and the increases in wnt4 mRNA and protein levels reached statistical significance in the hippocampus and striatum, respectively. This is the first finding to help elucidate the selective biosynthesis of central wnt4 through cAMP-stimulated microglia and astrocytes interaction. - Highlights: • Dibutyryl cAMP increased wnt4, but not wnt3a, 5a, 7a and 11, mRNA in mixed glia. • Wnt4 protein increased in astrocytes co-cultivated with microglia. • It took a long time to robustly increase wnt4 expression. • Rolipram

  3. Generation of pluripotent stem cells via protein transduction.

    Science.gov (United States)

    Li, Xia; Zhang, Pengfei; Wei, Chao; Zhang, Yunhai

    2014-01-01

    The development of techniques for reprogramming somatic cells led to the birth of the cloned sheep “Dolly” and the generation of induced pluripotent stem cells (iPSCs). iPSCs hold great promise for in vitro disease modeling, new drug screening, regenerative medicine and agricultural production. These cells can differentiate into almost any tissue types and they can be used to produce autografts that will not be rejected by the patient. However, practical application has been limited by the potential for insertion mutagenesis and by the complexity of the associated procedures. A protein-based approach to generation of iPSCs could offer better prospects by avoiding these problems. This review provides an overview of the key processes and mechanism involved in protein-based somatic cell reprogramming, discusses some promising methods for increasing its efficiency and future challenges.

  4. Timing the generation of distinct retinal cells by homeobox proteins.

    Directory of Open Access Journals (Sweden)

    Sarah Decembrini

    2006-09-01

    Full Text Available The reason why different types of vertebrate nerve cells are generated in a particular sequence is still poorly understood. In the vertebrate retina, homeobox genes play a crucial role in establishing different cell identities. Here we provide evidence of a cellular clock that sequentially activates distinct homeobox genes in embryonic retinal cells, linking the identity of a retinal cell to its time of generation. By in situ expression analysis, we found that the three Xenopus homeobox genes Xotx5b, Xvsx1, and Xotx2 are initially transcribed but not translated in early retinal progenitors. Their translation requires cell cycle progression and is sequentially activated in photoreceptors (Xotx5b and bipolar cells (Xvsx1 and Xotx2. Furthermore, by in vivo lipofection of "sensors" in which green fluorescent protein translation is under control of the 3' untranslated region (UTR, we found that the 3' UTRs of Xotx5b, Xvsx1, and Xotx2 are sufficient to drive a spatiotemporal pattern of translation matching that of the corresponding proteins and consistent with the time of generation of photoreceptors (Xotx5b and bipolar cells (Xvsx1 and Xotx2. The block of cell cycle progression of single early retinal progenitors impairs their differentiation as photoreceptors and bipolar cells, but is rescued by the lipofection of Xotx5b and Xvsx1 coding sequences, respectively. This is the first evidence to our knowledge that vertebrate homeobox proteins can work as effectors of a cellular clock to establish distinct cell identities.

  5. Wnt signaling during tooth replacement in zebrafish (Danio rerio: pitfalls and perspectives

    Directory of Open Access Journals (Sweden)

    Ann eHuysseune

    2014-10-01

    Full Text Available The canonical (β-catenin dependent Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1 in developing zebrafish (Danio rerio tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement.The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i potential technical pitfalls related to dose- or time-dependency, (ii the complexity of the canonical Wnt pathway, and (iii species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts.

  6. Wnt-11 signaling leads to down-regulation of the Wnt/β-catenin, JNK/AP-1 and NF-κB pathways and promotes viability in the CHO-K1 cells

    International Nuclear Information System (INIS)

    Railo, Antti; Nagy, Irina I.; Kilpelaeinen, Pekka; Vainio, Seppo

    2008-01-01

    The Wnt family of glycoprotein growth factors controls a number of central cellular processes such as proliferation, differentiation and ageing. All the Wnt proteins analyzed so far either activate or inhibit the canonical β-catenin signaling pathway that regulates transcription of the target genes. In addition, some of them activate noncanonical signaling pathways that involve components such as the JNK, heterotrimeric G proteins, protein kinase C, and calmodulin-dependent protein kinase II, although the precise signaling mechanisms are only just beginning to be revealed. We demonstrate here that Wnt-11 signaling is sufficient to inhibit not only the canonical β-catenin mediated Wnt signaling but also JNK/AP-1 and NF-κB signaling in the CHO cells, thus serving as a noncanonical Wnt ligand in this system. Inhibition of the JNK/AP-1 pathway is mediated in part by the MAPK kinase MKK4 and Akt. Moreover, protein kinase C is involved in the regulation of JNK/AP-1 by Wnt-11, but not of the NF-κB pathway. Consistent with the central role of Akt, JNK and NF-κB in cell survival and stress responses, Wnt-11 signaling promotes cell viability. Hence Wnt-11 is involved in coordination of key signaling pathways

  7. Porcine Circovirus-Like Virus P1 Inhibits Wnt Signaling Pathway in Vivo and in Vitro.

    Science.gov (United States)

    Zhu, Xuejiao; Wen, Libin; Sheng, Shaoyang; Wang, Wei; Xiao, Qi; Qu, Meng; Hu, Yiyi; Liu, Chuanmin; He, Kongwang

    2018-01-01

    Porcine circovirus-like virus P1 is an important pathogen of the current pig industry, the infection mechanism is not entirely clear. Wnt signaling pathway plays an important role in the growth of young animals and infection of some viruses. This study was designed to demonstrate the effects of P1 infection on the Wnt signaling pathway. In vivo experiments, we demonstrated the down-regulatory effects of P1 infection in piglets and mice on the downstream components expression levels of Wnt signaling pathway, and the effects of Wnt signaling pathway activation on the pathogenesis of P1. In vitro studies, we found P1 infection down-regulated protein level of β-catenin and mRNA level of mmp2, prevented the β-catenin from entering into nucleus, abolished the TCF/LEF promoter activity, proved that P1 could inhibit the activation of Wnt signaling pathway in vitro . Finally, we found that VP1 of P1 virus also had the inhibitory effects on Wnt signaling pathway in vitro , elucidated the mechanism of P1's inhibitory effects on the Wnt signaling pathway and offered the possibility that the suppression of Wnt signaling pathway was involved in the post-weaning multisystemic wasting syndrome (PMWS), laying a foundation for elucidating the pathogenesis of P1.

  8. Wnt ligand presentation and reception: from the stem cell niche to tissue engineering.

    Science.gov (United States)

    Mills, Kate M; Szczerkowski, James L A; Habib, Shukry J

    2017-08-01

    Stem cells reside in niches where spatially restricted signals maintain a delicate balance between stem cell self-renewal and differentiation. Wnt family proteins are particularly suited for this role as they are modified by lipids, which constrain and spatially regulate their signalling range. In recent years, Wnt/β-catenin signalling has been shown to be essential for the self-renewal of a variety of mammalian stem cells. In this review, we discuss Wnt-responsive stem cells in their niche, and mechanisms by which Wnt ligands are presented to responsive cells. We also highlight recent progress in molecular visualization that has allowed for the monitoring of Wnt signalling within the stem cell compartment and new approaches to recapitulate this niche signalling in vitro Indeed, new technologies that present Wnt in a localized manner and mimic the three-dimensional microenvironment of stem cells will advance our understanding of Wnt signalling in the stem cell niche. These advances will expand current horizons to exploit Wnt ligands in the rapidly evolving fields of tissue engineering and regenerative medicine. © 2017 The Authors.

  9. USP25 regulates Wnt signaling by controlling the stability of tankyrases.

    Science.gov (United States)

    Xu, Daichao; Liu, Jianping; Fu, Tao; Shan, Bing; Qian, Lihui; Pan, Lifeng; Yuan, Junying

    2017-05-15

    Aberrant activation of the Wnt signaling pathway plays an important role in human cancer development. Wnt signaling is negatively regulated by Axin, a scaffolding protein that controls a rate-limiting step in the destruction of β-catenin, the central activator of the Wnt pathway. In Wnt-stimulated cells, Axin is rapidly modified by tankyrase-mediated poly(ADP-ribosyl)ation, which promotes the proteolysis of Axin and consequent stabilization of β-catenin. Thus, regulation of the levels and activity of tankyrases is mechanistically important in controlling Wnt signaling. Here, we identify ubiquitin-specific protease 25 (USP25) as a positive regulator of Wnt/β-catenin signaling. We found that USP25 directly interacted with tankyrases to promote their deubiquitination and stabilization. We demonstrated that USP25 deficiency could promote the degradation of tankyrases and consequent stabilization of Axin to antagonize Wnt signaling. We further characterized the interaction between TNKS1 and USP25 by X-ray crystal structure determination. Our results provide important new insights into the molecular mechanism that regulates the turnover of tankyrases and the possibility of targeting the stability of tankyrases by antagonizing their interaction with USP25 to modulate the Wnt/β-catenin pathway. © 2017 Xu et al.; Published by Cold Spring Harbor Laboratory Press.

  10. Porcine Circovirus-Like Virus P1 Inhibits Wnt Signaling Pathway in Vivo and in Vitro

    Directory of Open Access Journals (Sweden)

    Xuejiao Zhu

    2018-03-01

    Full Text Available Porcine circovirus-like virus P1 is an important pathogen of the current pig industry, the infection mechanism is not entirely clear. Wnt signaling pathway plays an important role in the growth of young animals and infection of some viruses. This study was designed to demonstrate the effects of P1 infection on the Wnt signaling pathway. In vivo experiments, we demonstrated the down-regulatory effects of P1 infection in piglets and mice on the downstream components expression levels of Wnt signaling pathway, and the effects of Wnt signaling pathway activation on the pathogenesis of P1. In vitro studies, we found P1 infection down-regulated protein level of β-catenin and mRNA level of mmp2, prevented the β-catenin from entering into nucleus, abolished the TCF/LEF promoter activity, proved that P1 could inhibit the activation of Wnt signaling pathway in vitro. Finally, we found that VP1 of P1 virus also had the inhibitory effects on Wnt signaling pathway in vitro, elucidated the mechanism of P1’s inhibitory effects on the Wnt signaling pathway and offered the possibility that the suppression of Wnt signaling pathway was involved in the post-weaning multisystemic wasting syndrome (PMWS, laying a foundation for elucidating the pathogenesis of P1.

  11. Amino acid limitation induces down-regulation of WNT5a at transcriptional level

    International Nuclear Information System (INIS)

    Wang Zuguang; Chen Hong

    2009-01-01

    An aberrant WNT signaling contributes to the development and progression of multiple cancers. WNT5a is one of the WNT signaling molecules. This study was designed to test the hypothesis that amino acid deprivation induces changes in the WNT signaling pathway in colon cancer cells. Results showed that targets of the amino acid response pathway, ATF3 and p21, were induced in the human colon cancer cell line SW480 during amino acid limitation. There was a significant decrease in the WNT5a mRNA level following amino acid deprivation. The down-regulation of WNT5a mRNA by amino acid deprivation is not due to mRNA destabilization. There is a reduction of nuclear β-catenin protein level by amino acid limitation. Under amino acid limitation, phosphorylation of ERK1/2 was increased and the blockage of ERK1/2 by the inhibitor U0126 partially restored WNT5a mRNA level. In conclusion, amino acid limitation in colon cancer cells induces phosphorylation of ERK1/2, which then down-regulates WNT5a expression.

  12. Reengineering autologous bone grafts with the stem cell activator WNT3A.

    Science.gov (United States)

    Jing, Wei; Smith, Andrew A; Liu, Bo; Li, Jingtao; Hunter, Daniel J; Dhamdhere, Girija; Salmon, Benjamin; Jiang, Jie; Cheng, Du; Johnson, Chelsey A; Chen, Serafine; Lee, Katherine; Singh, Gurpreet; Helms, Jill A

    2015-04-01

    Autologous bone grafting represents the standard of care for treating bone defects but this biomaterial is unreliable in older patients. The efficacy of an autograft can be traced back to multipotent stem cells residing within the bone graft. Aging attenuates the viability and function of these stem cells, leading to inconsistent rates of bony union. We show that age-related changes in autograft efficacy are caused by a loss in endogenous Wnt signaling. Blocking this endogenous Wnt signal using Dkk1 abrogates autograft efficacy whereas providing a Wnt signal in the form of liposome-reconstituted WNT3A protein (L-WNT3A) restores bone forming potential to autografts from aged animals. The bioengineered autograft exhibits significantly better survival in the hosting site. Mesenchymal and skeletal stem cell populations in the autograft are activated by L-WNT3A and mitotic activity and osteogenic differentiation are significantly enhanced. In a spinal fusion model, aged autografts treated with L-WNT3A demonstrate superior bone forming capacity compared to the standard of care. Thus, a brief incubation in L-WNT3A reliably improves autologous bone grafting efficacy, which has the potential to significantly improve patient care in the elderly. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Wnt6, Wnt10a and Wnt10b inhibit adipogenesis and stimulate osteoblastogenesis through a β-catenin-dependent mechanism

    OpenAIRE

    Cawthorn, William P.; Bree, Adam J.; Yao, Yao; Du, Baowen; Hemati, Nahid; Martinez-Santibañez, Gabriel; MacDougald, Ormond A.

    2011-01-01

    Wnt10b is an established regulator of mesenchymal stem cell (MSC) fate that inhibits adipogenesis and stimulates osteoblastogenesis, thereby impacting bone mass in vivo. However, downstream mechanisms through which Wnt10b exerts these effects are poorly understood. Moreover, whether other endogenous Wnt ligands also modulate MSC fate remains to be fully addressed. In this study, we identify Wnt6 and Wnt10a as additional Wnt family members that, like Wnt10b, are downregulated during developmen...

  14. A C-terminally truncated form of β-catenin acts as a novel regulator of Wnt/β-catenin signaling in planarians.

    Directory of Open Access Journals (Sweden)

    Hanxia Su

    2017-10-01

    Full Text Available β-Catenin, the core element of the Wnt/β-catenin pathway, is a multifunctional and evolutionarily conserved protein which performs essential roles in a variety of developmental and homeostatic processes. Despite its crucial roles, the mechanisms that control its context-specific functions in time and space remain largely unknown. The Wnt/β-catenin pathway has been extensively studied in planarians, flatworms with the ability to regenerate and remodel the whole body, providing a 'whole animal' developmental framework to approach this question. Here we identify a C-terminally truncated β-catenin (β-catenin4, generated by gene duplication, that is required for planarian photoreceptor cell specification. Our results indicate that the role of β-catenin4 is to modulate the activity of β-catenin1, the planarian β-catenin involved in Wnt signal transduction in the nucleus, mediated by the transcription factor TCF-2. This inhibitory form of β-catenin, expressed in specific cell types, would provide a novel mechanism to modulate nuclear β-catenin signaling levels. Genomic searches and in vitro analysis suggest that the existence of a C-terminally truncated form of β-catenin could be an evolutionarily conserved mechanism to achieve a fine-tuned regulation of Wnt/β-catenin signaling in specific cellular contexts.

  15. A C-terminally truncated form of β-catenin acts as a novel regulator of Wnt/β-catenin signaling in planarians.

    Science.gov (United States)

    Su, Hanxia; Sureda-Gomez, Miquel; Rabaneda-Lombarte, Neus; Gelabert, Maria; Xie, Jianlei; Wu, Wei; Adell, Teresa

    2017-10-01

    β-Catenin, the core element of the Wnt/β-catenin pathway, is a multifunctional and evolutionarily conserved protein which performs essential roles in a variety of developmental and homeostatic processes. Despite its crucial roles, the mechanisms that control its context-specific functions in time and space remain largely unknown. The Wnt/β-catenin pathway has been extensively studied in planarians, flatworms with the ability to regenerate and remodel the whole body, providing a 'whole animal' developmental framework to approach this question. Here we identify a C-terminally truncated β-catenin (β-catenin4), generated by gene duplication, that is required for planarian photoreceptor cell specification. Our results indicate that the role of β-catenin4 is to modulate the activity of β-catenin1, the planarian β-catenin involved in Wnt signal transduction in the nucleus, mediated by the transcription factor TCF-2. This inhibitory form of β-catenin, expressed in specific cell types, would provide a novel mechanism to modulate nuclear β-catenin signaling levels. Genomic searches and in vitro analysis suggest that the existence of a C-terminally truncated form of β-catenin could be an evolutionarily conserved mechanism to achieve a fine-tuned regulation of Wnt/β-catenin signaling in specific cellular contexts.

  16. 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.

  17. 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.

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

    International Nuclear Information System (INIS)

    Sakisaka, Yukihiko; Tsuchiya, Masahiro; Nakamura, Takashi; Tamura, Masato; Shimauchi, Hidetoshi; Nemoto, Eiji

    2015-01-01

    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

  19. Hyaluronic acid enhances proliferation of human amniotic mesenchymal stem cells through activation of Wnt/β-catenin signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ru-Ming; Sun, Ren-Gang; Zhang, Ling-Tao; Zhang, Qing-Fang; Chen, Dai-Xiong [Guizhou Center for Translational Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Road, Zunyi 563000 (China); Zhong, Jian-Jiang, E-mail: jjzhong@sjtu.edu.cn [State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240 (China); Xiao, Jian-Hui, E-mail: jhxiao@yahoo.com [Guizhou Center for Translational Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Road, Zunyi 563000 (China)

    2016-07-15

    This study investigated the pro-proliferative effect of hyaluronic acid (HA) on human amniotic mesenchymal stem cells (hAMSCs) and the underlying mechanisms. Treatment with HA increased cell population growth in a dose- and time-dependent manner. Analyses by flow cytometry and immunocytochemistry revealed that HA did not change the cytophenotypes of hAMSCs. Additionally, the osteogenic, chondrogenic, and adipogenic differentiation capabilities of these hAMSCs were retained after HA treatment. Moreover, HA increased the mRNA expressions of wnt1, wnt3a, wnt8a, cyclin D1, Ki-67, and β-catenin as well as the protein level of β-catenin and cyclin D1 in hAMSCs; and the nuclear localization of β-catenin was also enhanced. Furthermore, the pro-proliferative effect of HA and up-regulated expression of Wnt/β-catenin pathway-associated proteins - wnt3a, β-catenin and cyclin D1 in hAMSCs were significantly inhibited upon pre-treatment with Wnt-C59, an inhibitor of the Wnt/β-catenin pathway. These results suggest that HA may positively regulate hAMSCs proliferation through regulation of the Wnt/β-catenin signaling pathway. - Highlights: • Hyaluronic acid (HA) could promote the proliferation of hAMSCs. • HA treatment dose not affect the pluripotency of hAMSCs. • HA increases hAMSCs proliferation through activation of Wnt/β-catenin signaling.

  20. 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.

  1. 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,

  2. Anteroposterior axis patterning by early canonical Wnt signaling during hemichordate development

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    Darras, Sébastien; Fritzenwanker, Jens H.; Uhlinger, Kevin R.; Farrelly, Ellyn; Pani, Ariel M.; Hurley, Imogen A.; Norris, Rachael P.; Osovitz, Michelle; Terasaki, Mark; Wu, Mike; Aronowicz, Jochanan; Kirschner, Marc; Gerhart, John C.

    2018-01-01

    The Wnt family of secreted proteins has been proposed to play a conserved role in early specification of the bilaterian anteroposterior (A/P) axis. This hypothesis is based predominantly on data from vertebrate embryogenesis as well as planarian regeneration and homeostasis, indicating that canonical Wnt (cWnt) signaling endows cells with positional information along the A/P axis. Outside of these phyla, there is strong support for a conserved role of cWnt signaling in the repression of anterior fates, but little comparative support for a conserved role in promotion of posterior fates. We further test the hypothesis by investigating the role of cWnt signaling during early patterning along the A/P axis of the hemichordate Saccoglossus kowalevskii. We have cloned and investigated the expression of the complete Wnt ligand and Frizzled receptor complement of S. kowalevskii during early development along with many secreted Wnt modifiers. Eleven of the 13 Wnt ligands are ectodermally expressed in overlapping domains, predominantly in the posterior, and Wnt antagonists are localized predominantly to the anterior ectoderm in a pattern reminiscent of their distribution in vertebrate embryos. Overexpression and knockdown experiments, in combination with embryological manipulations, establish the importance of cWnt signaling for repression of anterior fates and activation of mid-axial ectodermal fates during the early development of S. kowalevskii. However, surprisingly, terminal posterior fates, defined by posterior Hox genes, are unresponsive to manipulation of cWnt levels during the early establishment of the A/P axis at late blastula and early gastrula. We establish experimental support for a conserved role of Wnt signaling in the early specification of the A/P axis during deuterostome body plan diversification, and further build support for an ancestral role of this pathway in early evolution of the bilaterian A/P axis. We find strong support for a role of cWnt in

  3. Deregulated WNT signaling in childhood T-cell acute lymphoblastic leukemia

    International Nuclear Information System (INIS)

    Ng, O H; Erbilgin, Y; Firtina, S; Celkan, T; Karakas, Z; Aydogan, G; Turkkan, E; Yildirmak, Y; Timur, C; Zengin, E; Dongen, J J M van; Staal, F J T; Ozbek, U; Sayitoglu, M

    2014-01-01

    WNT signaling has been implicated in the regulation of hematopoietic stem cells and plays an important role during T-cell development in thymus. Here we investigated WNT pathway activation in childhood T-cell acute lymphoblastic leukemia (T-ALL) patients. To evaluate the potential role of WNT signaling in T-cell leukomogenesis, we performed expression analysis of key components of WNT pathway. More than 85% of the childhood T-ALL patients showed upregulated β-catenin expression at the protein level compared with normal human thymocytes. The impact of this upregulation was reflected in high expression of known target genes (AXIN2, c-MYC, TCF1 and LEF). Especially AXIN2, the universal target gene of WNT pathway, was upregulated at both mRNA and protein levels in ∼40% of the patients. When β-CATENIN gene was silenced by small interfering RNA, the cancer cells showed higher rates of apoptosis. These results demonstrate that abnormal WNT signaling activation occurs in a significant fraction of human T-ALL cases independent of known T-ALL risk factors. We conclude that deregulated WNT signaling is a novel oncogenic event in childhood T-ALL

  4. Role of the Wnt receptor Frizzled-1 in presynaptic differentiation and function

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    Alvarez Alejandra R

    2009-11-01

    Full Text Available Abstract Background The Wnt signaling pathway regulates several fundamental developmental processes and recently has been shown to be involved in different aspects of synaptic differentiation and plasticity. Some Wnt signaling components are localized at central synapses, and it is thus possible that this pathway could be activated at the synapse. Results We examined the distribution of the Wnt receptor Frizzled-1 in cultured hippocampal neurons and determined that this receptor is located at synaptic contacts co-localizing with presynaptic proteins. Frizzled-1 was found in functional synapses detected with FM1-43 staining and in synaptic terminals from adult rat brain. Interestingly, overexpression of Frizzled-1 increased the number of clusters of Bassoon, a component of the active zone, while treatment with the extracellular cysteine-rich domain (CRD of Frizzled-1 decreased Bassoon clustering, suggesting a role for this receptor in presynaptic differentiation. Consistent with this, treatment with the Frizzled-1 ligand Wnt-3a induced presynaptic protein clustering and increased functional presynaptic recycling sites, and these effects were prevented by co-treatment with the CRD of Frizzled-1. Moreover, in synaptically mature neurons Wnt-3a was able to modulate the kinetics of neurotransmitter release. Conclusion Our results indicate that the activation of the Wnt pathway through Frizzled-1 occurs at the presynaptic level, and suggest that the synaptic effects of the Wnt signaling pathway could be modulated by local activation through synaptic Frizzled receptors.

  5. Role of SDF-1 and Wnt signaling pathway in the myocardial fibrosis of hypertensive rats.

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    Shao, Shuai; Cai, Wenwei; Sheng, Jing; Yin, Lingni

    2015-01-01

    To investigate the effects of stromal cell-derived factor-1 (SDF-1) and Wnt signaling pathway on the bioactivities of myofibroblasts (MFs) and the expressions of SDF-1 and components of Wnt signaling pathway in the myocardium of spontaneously hypertensive rats (SHR). BMSCs were induced to differentiate into MFs in vitro, and SDF-1 and Wnt signaling pathway were independently or simultaneously blocked. Then, the migration of MFs and the secretion of Col I and α-SMA were determined in MFs. Heart function, progression of myocardial fibrosis and structure of the heart were evaluated. The expression of SDF-1 and components of Wnt signaling pathway in SHR was detected. TGF-β could induce the differentiation of BMSCs into B-MFs; Blocking SDF-1/CXCR4 axis and/or Wnt signaling pathway was able to inhibit the MFs migration and Col I secretion; Blocking Wnt signaling pathway inhibited the differentiation of BMSCs into MFs; Serum SDF-1 increased with the increase in blood pressure, and serum β-catenin elevated with the fluctuation of blood pressure; Protein and mRNA expressions of SDF-1 in the myocardium increased, and those of DKK-1 (an inhibitor of Wnt signaling pathway) and GSK-3 reduced in SHR. SDF-1 and Wnt signaling pathway are involved in the differentiation of BMSCs into MFs, as well as the migration and collagen secretion of MFs; Hypertension affects the expressions of SDF-1 and components of Wnt signaling pathway. In the myocardium of SHR, SDF-1 expression increases, but the expression of inhibitor of Wnt signaling pathway reduces.

  6. MEDELLER: homology-based coordinate generation for membrane proteins.

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    Kelm, Sebastian; Shi, Jiye; Deane, Charlotte M

    2010-11-15

    Membrane proteins (MPs) are important drug targets but knowledge of their exact structure is limited to relatively few examples. Existing homology-based structure prediction methods are designed for globular, water-soluble proteins. However, we are now beginning to have enough MP structures to justify the development of a homology-based approach specifically for them. We present a MP-specific homology-based coordinate generation method, MEDELLER, which is optimized to build highly reliable core models. The method outperforms the popular structure prediction programme Modeller on MPs. The comparison of the two methods was performed on 616 target-template pairs of MPs, which were classified into four test sets by their sequence identity. Across all targets, MEDELLER gave an average backbone root mean square deviation (RMSD) of 2.62 Å versus 3.16 Å for Modeller. On our 'easy' test set, MEDELLER achieves an average accuracy of 0.93 Å backbone RMSD versus 1.56 Å for Modeller. http://medeller.info; Implemented in Python, Bash and Perl CGI for use on Linux systems; Supplementary data are available at http://www.stats.ox.ac.uk/proteins/resources.

  7. Wnt Signaling in Cancer Stem Cell Biology

    NARCIS (Netherlands)

    de Sousa E Melo, Felipe; Vermeulen, Louis

    2016-01-01

    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

  8. Wnt signaling through the Ror receptor in the nervous system.

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    Petrova, Iveta M; Malessy, Martijn J; Verhaagen, Joost; Fradkin, Lee G; Noordermeer, Jasprina N

    2014-02-01

    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 and modulates cell migration, cell polarity, and convergent extension. Ror has also been implicated in two human skeletal disorders, brachydactyly type B and Robinow syndrome. Rors are widely expressed during metazoan development including domains in the nervous system. Here, we review recent progress in understanding the roles of the Ror receptors in neuronal migration, axonal pruning, axon guidance, and synaptic plasticity. The processes by which Ror signaling execute these diverse roles are still largely unknown, but they likely converge on cytoskeletal remodeling. In multiple species, Rors have been shown to act as Wnt receptors signaling via novel non-canonical Wnt pathways mediated in some tissues by the adapter protein disheveled and the non-receptor tyrosine kinase Src. Rors can either activate or repress Wnt target expression depending on the cellular context and can also modulate signal transduction by sequestering Wnt ligands away from their signaling receptors. Future challenges include the identification of signaling components of the Ror pathways and bettering our understanding of the roles of these pleiotropic receptors in patterning the nervous system.

  9. 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.

  10. Discovery and characterization of a potent Wnt and hedgehog signaling pathways dual inhibitor.

    Science.gov (United States)

    Ma, Haikuo; Chen, Qin; Zhu, Fang; Zheng, Jiyue; Li, Jiajun; Zhang, Hongjian; Chen, Shuaishuai; Xing, Haimei; Luo, Lusong; Zheng, Long Tai; He, Sudan; Zhang, Xiaohu

    2018-04-10

    Embryonic stem cell pathways such as hedgehog and Wnt pathways are central to the tumorigenic properties of cancer stem cells (CSC). Since CSCs are characterized by their ability to self-renew, form differentiated progeny, and develop resistance to anticancer therapies, targeting the Wnt and hedgehog signaling pathways has been an important strategy for cancer treatment. Although molecules targeting either Wnt or hedgehog are common, to the best of our knowledge, those targeting both pathways have not been documented. Here we report a small molecule (compound 1) that inhibits both Wnt (IC 50  = 0.5 nM) and hedgehog (IC 50  = 71 nM) pathways based on reporter gene assays. We further identified that the molecular target of 1 for Wnt pathway inhibition was porcupine (a member of the membrane-bound O-acyltransferase family of proteins), a post-translational modification node in Wnt signaling; while the target of 1 mitigating hedgehog pathway was Smoothened, a key G protein coupled receptor (GPCR) mediating hedgehog signal transduction. Preliminary analysis of structure-activity-relationship identified key functional elements for hedgehog/Wnt inhibition. In in vivo studies, compound 1 demonstrated good oral exposure and bioavailability while eliciting no overt toxicity in mice. An important consideration in cancer treatment is the potential therapeutic escape through compensatory activation of an interconnected pathway when only one signaling pathway is inhibited. Toward this end, compound 1 may not only lead to the development of new therapeutics for Wnt and hedgehog related cancers, but may also help to develop potential cancer treatment which needs to target Wnt and hedgehog signaling simultaneously. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  11. Targeting WNT Signaling for Multifaceted Glioblastoma Therapy

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    Matthew McCord

    2017-10-01

    Full Text Available The WNT signaling pathway has been of great interest to developmental biologists for decades and has more recently become a central topic for study in cancer biology. It is vital for cell growth and regulation of embryogenesis in many organ systems, particularly the CNS and its associated vasculature. We summarize the role of WNT in CNS development and describe how WNT signaling makes key contributions to malignant glioma stemness, invasiveness, therapeutic resistance, and angiogenesis. The role of WNT in these mechanisms, along with creation and maintainance of the blood-brain barrier (BBB, points to the potential of WNT as a multi-faceted target in malignant glioma therapy.

  12. Wnt signaling in form deprivation myopia of the mice retina.

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    Mingming Ma

    Full Text Available BACKGROUND: The canonical Wnt signaling pathway plays important roles in cellular proliferation and differentiation, axonal outgrowth, cellular maintenance in retinas. Here we test the hypothesis that elements of the Wnt signaling pathway are involved in the regulation of eye growth and prevention of myopia, in the mouse form-deprivation myopia model. METHODOLOGY/PRINCIPAL FINDINGS: (1 One hundred twenty-five C57BL/6 mice were randomly distributed into form-deprivation myopia and control groups. Form-deprivation myopia (FDM was induced by suturing the right eyelid, while the control group received no treatment. After 1, 2, and 4 weeks of treatment, eyes were assessed in vivo by cycloplegic retinoscopic refraction and axial length measurement by photography or A-scan ultrasonography. Levels of retinal Wnt2b, Fzd5 and β-catenin mRNA and protein were evaluated using RT-PCR and western blotting, respectively. (2 Another 96 mice were divided into three groups: control, drugs-only, and drugs+FDM (by diffuser. Experimentally treated eyes in the last two groups received intravitreal injections of vehicle or the proteins, DKK-1 (Wnt-pathway antagonist or Norrin (Wnt-pathway agonist, once every three days, for 4 injections total. Axial length and retinoscopic refraction were measured on the 14th day of form deprivation. Following form-deprivation for 1, 2, and 4 weeks, FDM eyes had a relatively myopic refractive error, compared with contralateral eyes. There were no significant differences in refractive error between right and left eye in control group. The amounts of Wnt2b, Fzd5 and β-catenin mRNA and protein were significantly greater in form-deprived myopia eyes than in control eyes.DKK-1 (antagonist reduced the myopic shift in refractive error and increase in axial elongation, whereas Norrin had the opposite effect in FDM eyes. CONCLUSIONS/SIGNIFICANCE: Our studies provide the first evidence that the Wnt2b signaling pathway may play a role in the

  13. Postnatal Deletion of Wnt7a Inhibits Uterine Gland Morphogenesis and Compromises Adult Fertility in Mice1

    Science.gov (United States)

    Dunlap, Kathrin A.; Filant, Justyna; Hayashi, Kanako; Rucker, Edmund B.; Song, Gwonhwa; Deng, Jian Min; Behringer, Richard R.; DeMayo, Franco J.; Lydon, John; Jeong, Jae-Wook; Spencer, Thomas E.

    2011-01-01

    The success of postnatal uterine morphogenesis dictates, in part, the embryotrophic potential and functional capacity of the adult uterus. The definitive role of Wnt7a in postnatal uterine development and adult function requires a conditional knockout, because global deletion disrupts müllerian duct patterning, specification, and cell fate in the fetus. The Wnt7a-null uterus appears to be posteriorized because of developmental defects in the embryo, as evidenced by the stratified luminal epithelium that is normally found in the vagina and the presence of short and uncoiled oviducts. To understand the biological role of WNT7A after birth and allow tissue-selective deletion of Wnt7a, we generated loxP-flanked exon 2 mice and conditionally deleted Wnt7a after birth in the uterus by crossing them with PgrCre mice. Morphological examination revealed no obvious differences in the vagina, cervix, oviduct, or ovary. The uteri of Wnt7a mutant mice contained no endometrial glands, whereas all other uterine cell types appeared to be normal. Postnatal differentiation of endometrial glands was observed in control mice, but not in mutant mice, between Postnatal Days 3 and 12. Expression of morphoregulatory genes, particularly Foxa2, Hoxa10, Hoxa11, Msx1, and Wnt16, was disrupted in the Wnt7a mutant uteri. Conditional Wnt7a mutant mice were not fertile. Although embryos were present in uteri of mutant mice on Day 3.5 of pregnancy, blastocyst implantation was not observed on Day 5.5. Furthermore, expression of several genes (Foxa2, Lif, Msx1, and Wnt16) was reduced or absent in adult Wnt7a-deleted uteri on Day 3.5 postmating. These results indicate that WNT7A plays a critical role in postnatal uterine gland morphogenesis and function, which are important for blastocyst implantation and fertility in the adult uterus. PMID:21508348

  14. 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.

  15. Canonical Wnt signaling in diabetic retinopathy.

    Science.gov (United States)

    Chen, Qian; Ma, Jian-Xing

    2017-10-01

    Diabetic retinopathy (DR) is a common eye complication of diabetes, and the pathogenic mechanism of DR is still under investigation. The canonical Wnt signaling pathway is an evolutionarily conserved pathway that plays fundamental roles in embryogenesis and adult tissue homeostasis. Wnt signaling regulates expression of multiple genes that control retinal development and eye organogenesis, and dysregulated Wnt signaling plays pathophysiological roles in many ocular diseases, including DR. This review highlights recent progress in studies of Wnt signaling in DR. We discuss Wnt signaling regulation in the retina and dysregulation of Wnt signaling associated with ocular diseases with an emphasis on DR. We also discuss the therapeutic potential of modulating Wnt signaling in DR. Continued studies in this field will advance our current understanding on DR and contribute to the development of new treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Wnt, RSPO and Hippo Signalling in the Intestine and Intestinal Stem Cells.

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    Kriz, Vitezslav; Korinek, Vladimir

    2018-01-08

    In this review, we address aspects of Wnt, R-Spondin (RSPO) and Hippo signalling, in both healthy and transformed intestinal epithelium. In intestinal stem cells (ISCs), the Wnt pathway is essential for intestinal crypt formation and renewal, whereas RSPO-mediated signalling mainly affects ISC numbers. In human colorectal cancer (CRC), aberrant Wnt signalling is the driving mechanism initiating this type of neoplasia. The signalling role of the RSPO-binding transmembrane proteins, the leucine-rich-repeat-containing G-protein-coupled receptors (LGRs), is possibly more pleiotropic and not only limited to the enhancement of Wnt signalling. There is growing evidence for multiple crosstalk between Hippo and Wnt/β-catenin signalling. In the ON state, Hippo signalling results in serine/threonine phosphorylation of Yes-associated protein (YAP1) and tafazzin (TAZ), promoting formation of the β-catenin destruction complex. In contrast, YAP1 or TAZ dephosphorylation (and YAP1 methylation) results in β-catenin destruction complex deactivation and β-catenin nuclear localization. In the Hippo OFF state, YAP1 and TAZ are engaged with the nuclear β-catenin and participate in the β-catenin-dependent transcription program. Interestingly, YAP1/TAZ are dispensable for intestinal homeostasis; however, upon Wnt pathway hyperactivation, the proteins together with TEA domain (TEAD) transcription factors drive the transcriptional program essential for intestinal cell transformation. In addition, in many CRC cells, YAP1 phosphorylation by YES proto-oncogene 1 tyrosine kinase (YES1) leads to the formation of a transcriptional complex that includes YAP1, β-catenin and T-box 5 (TBX5) DNA-binding protein. YAP1/β-catenin/T-box 5-mediated transcription is necessary for CRC cell proliferation and survival. Interestingly, dishevelled (DVL) appears to be an important mediator involved in both Wnt and Hippo (YAP1/TAZ) signalling and some of the DVL functions were assigned to the nuclear DVL

  17. Wnt, RSPO and Hippo Signalling in the Intestine and Intestinal Stem Cells

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    Vitezslav Kriz

    2018-01-01

    Full Text Available In this review, we address aspects of Wnt, R-Spondin (RSPO and Hippo signalling, in both healthy and transformed intestinal epithelium. In intestinal stem cells (ISCs, the Wnt pathway is essential for intestinal crypt formation and renewal, whereas RSPO-mediated signalling mainly affects ISC numbers. In human colorectal cancer (CRC, aberrant Wnt signalling is the driving mechanism initiating this type of neoplasia. The signalling role of the RSPO-binding transmembrane proteins, the leucine-rich-repeat-containing G-protein-coupled receptors (LGRs, is possibly more pleiotropic and not only limited to the enhancement of Wnt signalling. There is growing evidence for multiple crosstalk between Hippo and Wnt/β-catenin signalling. In the ON state, Hippo signalling results in serine/threonine phosphorylation of Yes-associated protein (YAP1 and tafazzin (TAZ, promoting formation of the β-catenin destruction complex. In contrast, YAP1 or TAZ dephosphorylation (and YAP1 methylation results in β-catenin destruction complex deactivation and β-catenin nuclear localization. In the Hippo OFF state, YAP1 and TAZ are engaged with the nuclear β-catenin and participate in the β-catenin-dependent transcription program. Interestingly, YAP1/TAZ are dispensable for intestinal homeostasis; however, upon Wnt pathway hyperactivation, the proteins together with TEA domain (TEAD transcription factors drive the transcriptional program essential for intestinal cell transformation. In addition, in many CRC cells, YAP1 phosphorylation by YES proto-oncogene 1 tyrosine kinase (YES1 leads to the formation of a transcriptional complex that includes YAP1, β-catenin and T-box 5 (TBX5 DNA-binding protein. YAP1/β-catenin/T-box 5-mediated transcription is necessary for CRC cell proliferation and survival. Interestingly, dishevelled (DVL appears to be an important mediator involved in both Wnt and Hippo (YAP1/TAZ signalling and some of the DVL functions were assigned to the

  18. GPR124 Functions as a WNT7-Specific Coactivator of Canonical β-Catenin Signaling

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    Ekaterina Posokhova

    2015-01-01

    Full Text Available G protein-coupled receptor 124 (GPR124 is an orphan receptor in the adhesion family of GPCRs, and previous global or endothelial-specific disruption of Gpr124 in mice led to defective CNS angiogenesis and blood-brain barriergenesis. Similar developmental defects were observed following dual deletion of Wnt7a/Wnt7b or deletion of β-catenin in endothelial cells, suggesting a possible relationship between GPR124 and canonical WNT signaling. Here, we show using in vitro reporter assays, mutation analysis, and genetic interaction studies in vivo that GPR124 functions as a WNT7A/WNT7B-specific costimulator of β-catenin signaling in brain endothelium. WNT7-stimulated β-catenin signaling was dependent upon GPR124’s intracellular PDZ binding motif and a set of leucine-rich repeats in its extracellular domain. This study reveals a vital role for GPR124 in potentiation of WNT7-induced canonical β-catenin signaling with important implications for understanding and manipulating CNS-specific angiogenesis and blood-brain barriergenesis.

  19. Cooperative and independent functions of FGF and Wnt signaling during early inner ear development.

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    Wright, Kevin D; Mahoney Rogers, Amanda A; Zhang, Jian; Shim, Katherine

    2015-10-06

    In multiple vertebrate organisms, including chick, Xenopus, and zebrafish, Fibroblast Growth Factor (FGF) and Wnt signaling cooperate during formation of the otic placode. However, in the mouse, although FGF signaling induces Wnt8a expression during induction of the otic placode, it is unclear whether these two signaling pathways functionally cooperate. Sprouty (Spry) genes encode intracellular antagonists of receptor tyrosine kinase signaling, including FGF signaling. We previously demonstrated that the Sprouty1 (Spry1) and Sprouty2 (Spry2) genes antagonize FGF signaling during induction of the otic placode. Here, we investigate cross talk between FGF/SPRY and Wnt signaling during otic placode induction and assess whether these two signaling pathways functionally cooperate during early inner ear development in the mouse. Embryos were generated carrying combinations of a Spry1 null allele, Spry2 null allele, β-catenin null allele, or a Wnt reporter transgene. Otic phenotypes were assessed by in situ hybridization, semi-quantitative reverse transcriptase PCR, immunohistochemistry, and morphometric analysis of sectioned tissue. Comparison of Spry1, Spry2, and Wnt reporter expression in pre-otic and otic placode cells indicates that FGF signaling precedes and is active in more cells than Wnt signaling. We provide in vivo evidence that FGF signaling activates the Wnt signaling pathway upstream of TCF/Lef transcriptional activation. FGF regulation of Wnt signaling is functional, since early inner ear defects in Spry1 and Spry2 compound mutant embryos can be genetically rescued by reducing the activity of the Wnt signaling pathway. Interestingly, we find that although the entire otic placode increases in size in Spry1 and Spry2 compound mutant embryos, the size of the Wnt-reporter-positive domain does not increase to the same extent as the Wnt-reporter-negative domain. This study provides genetic evidence that FGF and Wnt signaling cooperate during early inner ear

  20. Cyclin G2 suppresses estrogen-mediated osteogenesis through inhibition of Wnt/β-catenin signaling.

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    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.

  1. 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

  2. Wnt5a regulates dental follicle stem/progenitor cells of the periodontium.

    Science.gov (United States)

    Xiang, Lusai; Chen, Mo; He, Ling; Cai, Bin; Du, Yu; Zhang, Xinchun; Zhou, Chen; Wang, Chenglin; Mao, Jeremy J; Ling, Junqi

    2014-12-15

    Dental follicle gives rise to one or several tissues of the periodontium including the periodontal ligament, cementum and/or alveolar bone. Whether Wnt5a is expressed in the postnatal periodontium or regulates dental follicle stem/progenitor cells is unknown. Dental follicle stem/progenitor cells were isolated from postnatal day 1 (p1) to p11 from rat mandibular first molars. Immunolocalization mapped Wnt5a expression in the alveolar bone, periodontal ligament, and the developing ameloblast and odontoblast layers. Mononucleated and adherent cells were isolated from p7 dental follicle. Wnt5a was overexpressed in dental follicle stem/progenitor cells to study their proliferation, osteogenic differentiation and migration behavior, with subpopulations of native dental follicle stem/progenitor cells as controls, using real-time PCR (Taqman), Lenti-viral transfection, Western blotting and immunofluorescence. Wnt5a was expressed consistently in p1 to p11 rat peridontium. Native, p7 dental follicle stem/progenitor cells had modest ability to mineralize in the tested 14 days. Even in chemically defined osteogenesis medium, dental follicle stem/progenitor cells only showed modest mineralization. Upon addition of 300 ng/mL Wnt5a protein in osteogenesis medium, dental follicle stem/progenitor cells displayed mineralization that was still unremarkable. Chemically induced or Wnt5a-induced mineralization of dental follicle cells only occurred sparsely. Combination of Wnt5a with 100 ng/mL BMP2 finally prompted dental follicle stem/progenitor cells to produce robust mineralization with elevated expression of Runx2, alkaline phosphatase, collagen 1α1 and osteocalcin. Thus, native dental follicle stem/progenitor cells or some of their fractions may be somewhat modest in mineralization. Strikingly, Wnt5a protein significantly augmented RANKL ligand, suggesting putative regulatory roles of dental follicle stem/progenitor cells for the monocyte/osteoclast lineage and potential

  3. Dynamic expression of Lgr5, a Wnt target gene, in the developing and mature mouse cochlea.

    Science.gov (United States)

    Chai, Renjie; Xia, Anping; Wang, Tian; Jan, Taha Adnan; Hayashi, Toshinori; Bermingham-McDonogh, Olivia; Cheng, Alan Gi-Lun

    2011-08-01

    The Wnt signaling pathway is a recurring theme in tissue development and homeostasis. Its specific roles during inner ear development are just emerging, but few studies have characterized Wnt target genes. Lgr5, a member of the G protein-coupled receptor family, is a Wnt target in the gastrointestinal and integumentary systems. Although its function is unknown, its deficiency leads to perinatal lethality due to gastrointestinal distension. In this study, we used a knock-in reporter mouse to examine the spatiotemporal expression of Lgr5 in the cochlear duct during embryonic and postnatal periods. In the embryonic day 15.5 (E15.5) cochlear duct, Lgr5-EGFP is expressed in the floor epithelium and overlapped with the prosensory markers Sox2, Jagged1, and p27(Kip1). Nascent hair cells and supporting cells in the apical turn of the E18.5 cochlear duct express Lgr5-EGFP, which becomes downregulated in hair cells and subsets of supporting cells in more mature stages. In situ hybridization experiments validated the reporter expression, which gradually decreases until the second postnatal week. Only the third row of Deiters' cells expresses Lgr5-EGFP in the mature organ of Corti. Normal cochlear development was observed in Lgr5(EGFP/EGFP) and Lgr5(EGFP/+) mice, which exhibited normal auditory thresholds. The expression pattern of Lgr5 contrasts with another Wnt target gene, Axin2, a feedback inhibitor of the Wnt pathway. Robust Axin2 expression was found in cells surrounding the embryonic cochlear duct and becomes restricted to tympanic border cells below the basilar membrane in the postnatal cochlea. Both Lgr5 and Axin2 act as Wnt targets in the cochlea because purified Wnt3a promoted and Wnt antagonist suppressed their expression. Their differential expression among cell populations highlights the dynamic but complex distribution of Wnt-activated cells in and around the embryonic and postnatal cochlea.

  4. The role of glypicans in Wnt inhibitory factor-1 activity and the structural basis of Wif1's effects on Wnt and Hedgehog signaling.

    Directory of Open Access Journals (Sweden)

    Andrei Avanesov

    Full Text Available Proper assignment of cellular fates relies on correct interpretation of Wnt and Hedgehog (Hh signals. Members of the Wnt Inhibitory Factor-1 (WIF1 family are secreted modulators of these extracellular signaling pathways. Vertebrate WIF1 binds Wnts and inhibits their signaling, but its Drosophila melanogaster ortholog Shifted (Shf binds Hh and extends the range of Hh activity in the developing D. melanogaster wing. Shf activity is thought to depend on reinforcing interactions between Hh and glypican HSPGs. Using zebrafish embryos and the heterologous system provided by D. melanogaster wing, we report on the contribution of glypican HSPGs to the Wnt-inhibiting activity of zebrafish Wif1 and on the protein domains responsible for the differences in Wif1 and Shf specificity. We show that Wif1 strengthens interactions between Wnt and glypicans, modulating the biphasic action of glypicans towards Wnt inhibition; conversely, glypicans and the glypican-binding "EGF-like" domains of Wif1 are required for Wif1's full Wnt-inhibiting activity. Chimeric constructs between Wif1 and Shf were used to investigate their specificities for Wnt and Hh signaling. Full Wnt inhibition required the "WIF" domain of Wif1, and the HSPG-binding EGF-like domains of either Wif1 or Shf. Full promotion of Hh signaling requires both the EGF-like domains of Shf and the WIF domains of either Wif1 or Shf. That the Wif1 WIF domain can increase the Hh promoting activity of Shf's EGF domains suggests it is capable of interacting with Hh. In fact, full-length Wif1 affected distribution and signaling of Hh in D. melanogaster, albeit weakly, suggesting a possible role for Wif1 as a modulator of vertebrate Hh signaling.

  5. Wnt Signaling in Kidney Development and Disease.

    Science.gov (United States)

    Wang, Yongping; Zhou, Chengji J; Liu, Youhua

    2018-01-01

    Wnt signal cascade is an evolutionarily conserved, developmental pathway that regulates embryogenesis, injury repair, and pathogenesis of human diseases. It is well established that Wnt ligands transmit their signal via canonical, β-catenin-dependent and noncanonical, β-catenin-independent mechanisms. Mounting evidence has revealed that Wnt signaling plays a key role in controlling early nephrogenesis and is implicated in the development of various kidney disorders. Dysregulations of Wnt expression cause a variety of developmental abnormalities and human diseases, such as congenital anomalies of the kidney and urinary tract, cystic kidney, and renal carcinoma. Multiple Wnt ligands, their receptors, and transcriptional targets are upregulated during nephron formation, which is crucial for mediating the reciprocal interaction between primordial tissues of ureteric bud and metanephric mesenchyme. Renal cysts are also associated with disrupted Wnt signaling. In addition, Wnt components are important players in renal tumorigenesis. Activation of Wnt/β-catenin is instrumental for tubular repair and regeneration after acute kidney injury. However, sustained activation of this signal cascade is linked to chronic kidney diseases and renal fibrosis in patients and experimental animal models. Mechanistically, Wnt signaling controls a diverse array of biologic processes, such as cell cycle progression, cell polarity and migration, cilia biology, and activation of renin-angiotensin system. In this chapter, we have reviewed recent findings that implicate Wnt signaling in kidney development and diseases. Targeting this signaling may hold promise for future treatment of kidney disorders in patients. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Wnt/catenin β1/microRNA 183 predicts recurrence and prognosis of patients with colorectal cancer.

    Science.gov (United States)

    Chen, Yuzhuo; Song, Weiliang

    2018-04-01

    The present study assessed the association between the Wnt/catenin β1 (CTNNB1)/microRNA (miR)183 signaling pathway and the recurrence and prognosis of colorectal cancer. The expression of Wnt, CTNNB1 and miR183 in primary colorectal cancer tissue was increased compared with that in the paracarcinoma tissue. Disease-free survival and overall survival were decreased in patients with colorectal cancer and increased miR183 expression compared with those in patients with colorectal cancer and decreased miR183 expression. The human colorectal cancer cell line HCT-116 was treated with 5 µM inhibitor of Wnt response (IWR-2) for 24 h to inhibit Wnt protein expression. Downregulating Wnt and CTNNB1 expression inhibited the viability of, and induced cell death and caspase 3 protein expression in, HCT-116 cells. The expression of BCL2 associated X protein and miR183 was increased, and cyclin D1 protein expression was suppressed, by the downregulation of Wnt and CTNNB1 expression in HCT-116 cells. Collectively, the results of the present study suggested that the Wnt/CTNNB1/miR183 signaling pathway may represent a promising biomarker for the recurrence and prognosis of colorectal cancer.

  7. Activation of Intracellular Calcium by Multiple Wnt Ligands and Translocation of β-Catenin into the Nucleus

    Science.gov (United States)

    Thrasivoulou, Christopher; Millar, Michael; Ahmed, Aamir

    2013-01-01

    Ca2+ and β-catenin, a 92-kDa negatively charged transcription factor, transduce Wnt signaling via the non-canonical, Wnt/Ca2+ and canonical, Wnt/β-catenin pathways independently. The nuclear envelope is a barrier to large protein entry, and this process is regulated by intracellular calcium [Ca2+]i and trans-nuclear potential. How β-catenin traverses the nuclear envelope is not well known. We hypothesized that Wnt/Ca2+ and Wnt/β-catenin pathways act in a coordinated manner and that [Ca2+]i release facilitates β-catenin entry into the nucleus in mammalian cells. In a live assay using calcium dyes in PC3 prostate cancer cells, six Wnt peptides (3A, 4, 5A, 7A, 9B, and 10B) mobilized [Ca2+]i but Wnt11 did not. Based upon dwell time (range = 15–30 s) of the calcium waveform, these Wnts could be classified into three classes: short, 3A and 5A; long, 7A and 10B; and very long, 4 and 9B. Wnt-activated [Ca2+]i release was followed by an increase in intranuclear calcium and the depolarization of both the cell and nuclear membranes, determined by using FM4-64. In cells treated with Wnts 5A, 9B, and 10B, paradigm substrates for each Wnt class, increased [Ca2+]i was followed by β-catenin translocation into the nucleus in PC3, MCF7, and 253J, prostate, breast, and bladder cancer cell lines; both the increase in Wnt 5A, 9B, and 10B induced [Ca2+]i release and β-catenin translocation are suppressed by thapsigargin in PC3 cell line. We propose a convergent model of Wnt signaling network where Ca2+ and β-catenin pathways may act in a coordinated, interdependent, rather than independent, manner. PMID:24158438

  8. Protein purification and analysis: next generation Western blotting techniques.

    Science.gov (United States)

    Mishra, Manish; Tiwari, Shuchita; Gomes, Aldrin V

    2017-11-01

    Western blotting is one of the most commonly used techniques in molecular biology and proteomics. Since western blotting is a multistep protocol, variations and errors can occur at any step reducing the reliability and reproducibility of this technique. Recent reports suggest that a few key steps, such as the sample preparation method, the amount and source of primary antibody used, as well as the normalization method utilized, are critical for reproducible western blot results. Areas covered: In this review, improvements in different areas of western blotting, including protein transfer and antibody validation, are summarized. The review discusses the most advanced western blotting techniques available and highlights the relationship between next generation western blotting techniques and its clinical relevance. Expert commentary: Over the last decade significant improvements have been made in creating more sensitive, automated, and advanced techniques by optimizing various aspects of the western blot protocol. New methods such as single cell-resolution western blot, capillary electrophoresis, DigiWest, automated microfluid western blotting and microchip electrophoresis have all been developed to reduce potential problems associated with the western blotting technique. Innovative developments in instrumentation and increased sensitivity for western blots offer novel possibilities for increasing the clinical implications of western blot.

  9. Epsin is required for Dishevelled stability and Wnt signaling 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

    2015-01-01

    Uncontrolled canonical Wnt signaling supports colon epithelial tumor 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, epsins’ involvement 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 signaling effector, dishevelled (Dvl2), and impairing Wnt signaling. 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 signaling in colon cancer cells to ensure robust colon cancer progression. Epsins’ pro-carcinogenic role suggests they are potential therapeutic targets to combat colon cancer. PMID:25871009

  10. The Mingle-Mangle of Wnt Signaling and Extracellular Vesicles: Functional Implications for Heart Research

    Directory of Open Access Journals (Sweden)

    Julia Christina Gross

    2018-02-01

    Full Text Available Wnt signaling is an important pathway in health and disease and a key regulator of stem cell maintenance, differentiation, and proliferation. During heart development, Wnt signaling controls specification, proliferation and differentiation of cardiovascular cells. In this regard, the role of activated Wnt signaling in cardiogenesis is well defined. However, the knowledge about signaling transmission has been challenged. Recently, the packaging of hydrophobic Wnt proteins on extracellular vesicles (EVs has emerged as a mechanism to facilitate their extracellular spreading and their functioning as morphogens. EVs spread systemically and therefore can have pleiotropic effects on very different cell types. They are heavily studied in tumor biology where they affect tumor growth and vascularization and can serve as biomarkers in liquid biopsies. In this review we will highlight recent discoveries of factors involved in the release of Wnts on EVs and its potential implications in the communication between physiological and pathological heart cells.

  11. Wnt-5a and Wnt-4 Regulates Cell Growth in C57MG Mammary Epithelial Cells

    National Research Council Canada - National Science Library

    Olson, Daniel

    1998-01-01

    .... That is, it is important ultimately to understand whether the inappropriate down regulation of certain wnt-genes that are spatially-temporally expressed in developing mammary glands, such as wnt-5a...

  12. Neural stem cells in the adult ciliary epithelium express GFAP and are regulated by Wnt signaling

    International Nuclear Information System (INIS)

    Das, Ani V.; Zhao Xing; James, Jackson; Kim, Min; Cowan, Kenneth H.; Ahmad, Iqbal

    2006-01-01

    The identification of neural stem cells with retinal potential in the ciliary epithelium (CE) of the adult mammals is of considerable interest because of their potential for replacing or rescuing degenerating retinal neurons in disease or injury. The evaluation of such a potential requires characterization of these cells with regard to their phenotypic properties, potential, and regulatory mechanisms. Here, we demonstrate that rat CE stem cells/progenitors in neurosphere culture display astrocytic nature in terms of expressing glial intermediate neurofilament protein, GFAP. The GFAP-expressing CE stem cells/progenitors form neurospheres in proliferating conditions and generate neurons when shifted to differentiating conditions. These cells express components of the canonical Wnt pathway and its activation promotes their proliferation. Furthermore, we demonstrate that the activation of the canonical Wnt pathway influences neuronal differentiation of CE stem cells/progenitors in a context dependent manner. Our observations suggest that CE stem cells/progenitors share phenotypic properties and regulatory mechanism(s) with neural stem cells elsewhere in the adult CNS

  13. Genetic deficiency of Wnt5a diminishes disease severity in a murine model of rheumatoid arthritis.

    Science.gov (United States)

    MacLauchlan, Susan; Zuriaga, Maria A; Fuster, José J; Cuda, Carla M; Jonason, Jennifer; Behzadi, Fernanda; Duffen, Jennifer Parker; Haines, G Kenneth; Aprahamian, Tamar; Perlman, Harris; Walsh, Kenneth

    2017-07-19

    Rheumatoid arthritis (RA) is a common autoimmune disease characterized by chronic inflammation of the joints, leading to bone erosion and joint dysfunction. Despite the recent successes of disease-modifying anti-rheumatic drugs (DMARDs), there is still clinical need for understanding the development and molecular etiology of RA. Wnts are developmental morphogens whose roles in adult pathology are poorly characterized. Wnt5a is a member of the non-canonical family of Wnts that modulates a wide range of cell processes, including differentiation, migration, and inflammation. Wnt5a has been implicated as a possible contributor to arthritis and it is upregulated in synovial fibroblasts from RA patients. We investigated the role of endogenous Wnt5a in RA. Tamoxifen-inducible, Wnt5a knockout (Wnt5a cKO) mice and littermate controls were monitored for arthritis development and joint pathology using the K/BxN serum transfer-induced arthritis (STIA) model. To explore a role of Wnt5a in osteoclast fusion, bone marrow-derived monocytes (BMDMs) were differentiated in vitro. Wnt5a cKO mice were resistant to arthritis development compared to control littermates as assessed by ankle thickness and histologic measurements. Some parameters of inflammation were reduced in the Wnt5a cKO mice, including the extent of polymononuclear cell infiltration and extra-articular inflammation. Wnt5a cKO mice also exhibited less cartilage destruction and a reduction in osteoclast activity with concomitant reduction in tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), macrophage colony-stimulating factor (MCSF), matrix metalloproteinase (MMP)2 and MMP9 in the arthritic joints. Treatment of BMDMs with Wnt5a enhanced osteoclast fusion and increased the expression of dendrocyte-expressed seven transmembrane protein (DCSTAMP) and MMP9, that are necessary for osteoclast formation and activity. These data suggest that Wnt5a modulates the development of arthritis by promoting

  14. NFAT5 regulates the canonical Wnt pathway and is required for cardiomyogenic differentiation

    International Nuclear Information System (INIS)

    Adachi, Atsuo; Takahashi, Tomosaburo; Ogata, Takehiro; Imoto-Tsubakimoto, Hiroko; Nakanishi, Naohiko; Ueyama, Tomomi; Matsubara, Hiroaki

    2012-01-01

    Highlights: ► NFAT5 protein expression is downregulated during cardiomyogenesis. ► Inhibition of NFAT5 function suppresses canonical Wnt signaling. ► Inhibition of NFAT5 function attenuates mesodermal induction. ► NFAT5 function is required for cardiomyogenesis. -- Abstract: While nuclear factor of activated T cells 5 (NFAT5), a transcription factor implicated in osmotic stress response, is suggested to be involved in other processes such as migration and proliferation, its role in cardiomyogenesis is largely unknown. Here, we examined the role of NFAT5 in cardiac differentiation of P19CL6 cells, and observed that it was abundantly expressed in undifferentiated P19CL6 cells, and its protein expression was significantly downregulated by enhanced proteasomal degradation during DMSO-induced cardiomyogenesis. Expression of a dominant negative mutant of NFAT5 markedly attenuated cardiomyogenesis, which was associated with the inhibition of mesodermal differentiation. TOPflash reporter assay revealed that the transcriptional activity of canonical Wnt signaling was activated prior to mesodermal differentiation, and this activation was markedly attenuated by NFAT5 inhibition. Pharmacological activation of canonical Wnt signaling by [2′Z, 3′E]-6-bromoindirubin-3′-oxime (BIO) restored Brachyury expression in NFAT5DN-expressing cells. Inhibition of NFAT5 markedly attenuated Wnt3 and Wnt3a induction. Expression of Dkk1 and Cerberus1, which are secreted Wnt antagonists, was also inhibited by NFAT5 inhibition. Thus, endogenous NFAT5 regulates the coordinated expression of Wnt ligands and antagonists, which are essential for cardiomyogenesis through the canonical Wnt pathway. These results demonstrated a novel role of NFAT5 in cardiac differentiation of stem cells.

  15. Avian WNT4 in the female reproductive tracts: potential role of oviduct development and ovarian carcinogenesis.

    Directory of Open Access Journals (Sweden)

    Chul-Hong Lim

    Full Text Available The wingless-type MMTV integration site family of proteins (WNTs is highly conserved secreted lipid-modified signaling molecules that play a variety of pivotal roles in developmental events such as embryogenesis, tissue homeostasis and cell polarity. Although, of these proteins, WNT4 is known to be involved in genital development in fetuses of mammalian species, its role is unknown in avian species. Therefore, in this study, we investigated expression profiles, as well as hormonal and post-transcriptional regulation of WNT4 expression in the reproductive tract of female chickens. Results of this study demonstrated that WNT4 is most abundant in the stromal and luminal epithelial cells of the isthmus and shell gland of the oviduct, respectively. WNT4 is also most abundant in the glandular epithelium of the shell gland of the oviduct of laying hens at 3 h post-ovulation during the laying cycle. In addition, treatment of young chicks with diethylstilbestrol (DES, a synthetic estrogen agonist stimulated WNT4 only in the glandular epithelial cells of the isthmus and shell gland of the oviduct. Moreover, results of our study demonstrated that miR-1786 influences WNT4 expression via specific binding sites in its 3'-UTR. On the other hand, our results also indicate that WNT4 is expressed predominantly in the glandular epithelium of cancerous ovaries, but not in normal ovaries of hens. Collectively, these results indicate cell-specific expression of WNT4 in the reproductive tract of chickens and that it likely has crucial roles in development and function of oviduct as well as initiation of ovarian carcinogenesis in laying hens.

  16. Avian WNT4 in the female reproductive tracts: potential role of oviduct development and ovarian carcinogenesis.

    Science.gov (United States)

    Lim, Chul-Hong; Lim, Whasun; Jeong, Wooyoung; Lee, Jin-Young; Bae, Seung-Min; Kim, Jinyoung; Han, Jae Yong; Bazer, Fuller W; Song, Gwonhwa

    2013-01-01

    The wingless-type MMTV integration site family of proteins (WNTs) is highly conserved secreted lipid-modified signaling molecules that play a variety of pivotal roles in developmental events such as embryogenesis, tissue homeostasis and cell polarity. Although, of these proteins, WNT4 is known to be involved in genital development in fetuses of mammalian species, its role is unknown in avian species. Therefore, in this study, we investigated expression profiles, as well as hormonal and post-transcriptional regulation of WNT4 expression in the reproductive tract of female chickens. Results of this study demonstrated that WNT4 is most abundant in the stromal and luminal epithelial cells of the isthmus and shell gland of the oviduct, respectively. WNT4 is also most abundant in the glandular epithelium of the shell gland of the oviduct of laying hens at 3 h post-ovulation during the laying cycle. In addition, treatment of young chicks with diethylstilbestrol (DES, a synthetic estrogen agonist) stimulated WNT4 only in the glandular epithelial cells of the isthmus and shell gland of the oviduct. Moreover, results of our study demonstrated that miR-1786 influences WNT4 expression via specific binding sites in its 3'-UTR. On the other hand, our results also indicate that WNT4 is expressed predominantly in the glandular epithelium of cancerous ovaries, but not in normal ovaries of hens. Collectively, these results indicate cell-specific expression of WNT4 in the reproductive tract of chickens and that it likely has crucial roles in development and function of oviduct as well as initiation of ovarian carcinogenesis in laying hens.

  17. Batch mode generation of residue-based diagrams of proteins.

    NARCIS (Netherlands)

    Campagne, F.; Bettler, E.J.M.; Vriend, G.; Weinstein, H.C.

    2003-01-01

    SUMMARY: Residue-based diagrams of proteins are graphical representations that can be used in protein information systems. These diagrams make it possible to visually integrate different types of biological information. The approach has been used successfully for membrane proteins. We developed the

  18. Wnt and the Wnt signaling pathway in bone development and disease

    Science.gov (United States)

    Wang, Yiping; Li, Yi-Ping; Paulson, Christie; Shao, Jian-Zhong; Zhang, Xiaoling; Wu, Mengrui; Chen, Wei

    2014-01-01

    Wnt signaling affects both bone modeling, which occurs during development, and bone remodeling, which is a lifelong process involving tissue renewal. Wnt signals are especially known to affect the differentiation of osteoblasts. In this review, we summarize recent advances in understanding the mechanisms of Wnt signaling, which is divided into two major branches: the canonical pathway and the noncanonical pathway. The canonical pathway is also called the Wnt/β-catenin pathway. There are two major noncanonical pathways: the Wnt-planar cell polarity pathway (Wnt-PCP pathway) and the Wnt-calcium pathway (Wnt-Ca2+ pathway). This review also discusses how Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists affect both the bone modeling and bone remodeling processes. We also review the role of Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists in bone as demonstrated in mouse models. Disrupted Wnt signaling is linked to several bone diseases, including osteoporosis, van Buchem disease, and sclerosteosis. Studying the mechanism of Wnt signaling and its interactions with other signaling pathways in bone will provide potential therapeutic targets to treat these bone diseases. PMID:24389191

  19. WNT-5A and WNT-5B modulate calcium homeostasis in airway smooth muscle

    NARCIS (Netherlands)

    Koopmans, Tim; Kumawat, Kudleer; Van Den Berge, Maarten; Hoffmann, Roland; Halayko, Andrew J.; Gosens, Reinoud

    2014-01-01

    Rationale Airway hyperresponsiveness is a common feature of asthma explained in part by an excessive contractile response of the airway smooth muscle (ASM). The underlying mechanisms are complex and in need of study. WNT-5A and WNT-5B, two members of the WNT signaling pathway, may be of

  20. A Wnt1 regulated Frizzled-1/β-Catenin signaling pathway as a candidate regulatory circuit controlling mesencephalic dopaminergic neuron-astrocyte crosstalk: Therapeutical relevance for neuron survival and neuroprotection

    Directory of Open Access Journals (Sweden)

    Pluchino Stefano

    2011-07-01

    Full Text Available Abstract Background Dopamine-synthesizing (dopaminergic, DA neurons in the ventral midbrain (VM constitute a pivotal neuronal population controlling motor behaviors, cognitive and affective brain functions, which generation critically relies on the activation of Wingless-type MMTV integration site (Wnt/β-catenin pathway in their progenitors. In Parkinson's disease, DA cell bodies within the substantia nigra pars compacta (SNpc progressively degenerate, with causes and mechanisms poorly understood. Emerging evidence suggests that Wnt signaling via Frizzled (Fzd receptors may play a role in different degenerative states, but little is known about Wnt signaling in the adult midbrain. Using in vitro and in vivo model systems of DA degeneration, along with functional studies in both intact and SN lesioned mice, we herein highlight an intrinsic Wnt1/Fzd-1/β-catenin tone critically contributing to the survival and protection of adult midbrain DA neurons. Results In vitro experiments identifie Fzd-1 receptor expression at a mRNA and protein levels in dopamine transporter (DAT expressing neurons, and demonstrate the ability of exogenous Wnt1 to exert robust neuroprotective effects against Caspase-3 activation, the loss of tyrosine hydroxylase-positive (TH+ neurons and [3H] dopamine uptake induced by different DA-specific insults, including serum and growth factor deprivation, 6-hydroxydopamine and MPTP/MPP+. Co-culture of DA neurons with midbrain astrocytes phenocopies Wnt1 neuroprotective effects, whereas RNA interference-mediated knockdown of Wnt1 in midbrain astrocytes markedly reduces astrocyte-induced TH+ neuroprotection. Likewise, silencing β-catenin mRNA or knocking down Fzd-1 receptor expression in mesencephalic neurons counteract astrocyte-induced TH+ neuroprotection. In vivo experiments document Fzd-1 co-localization with TH+ neurons within the intact SNpc and blockade of Fzd/β-catenin signaling by unilateral infusion of a Fzd

  1. The Wnt signalling pathway is upregulated in an in vitro model of acquired tamoxifen resistant breast cancer

    International Nuclear Information System (INIS)

    Loh, Yan Ni; Hedditch, Ellen L; Baker, Laura A; Jary, Eve; Ward, Robyn L; Ford, Caroline E

    2013-01-01

    Acquired resistance to Tamoxifen remains a critical problem in breast cancer patient treatment, yet the underlying causes of resistance have not been fully elucidated. Abberations in the Wnt signalling pathway have been linked to many human cancers, including breast cancer, and appear to be associated with more metastatic and aggressive types of cancer. Here, our aim was to investigate if this key pathway was involved in acquired Tamoxifen resistance, and could be targeted therapeutically. An in vitro model of acquired Tamoxifen resistance (named TamR) was generated by growing the estrogen receptor alpha (ER) positive MCF7 breast cancer cell line in increasing concentrations of Tamoxifen (up to 5 uM). Alterations in the Wnt signalling pathway and epithelial to mesenchymal transition (EMT) in response to Tamoxifen and treatment with the Wnt inhibitor, IWP-2 were measured via quantitative RT-PCR (qPCR) and TOP/FOP Wnt reporter assays. Resistance to Tamoxifen, and effects of IWP-2 treatment were determined by MTT proliferation assays. TamR cells exhibited increased Wnt signalling as measured via the TOP/FOP Wnt luciferase reporter assays. Genes associated with both the β-catenin dependent (AXIN2, MYC, CSNK1A1) and independent arms (ROR2, JUN), as well as general Wnt secretion (PORCN) of the Wnt signalling pathway were upregulated in the TamR cells compared to the parental MCF7 cell line. Treatment of the TamR cell line with human recombinant Wnt3a (rWnt3a) further increased the resistance of both MCF7 and TamR cells to the anti-proliferative effects of Tamoxifen treatment. TamR cells demonstrated increased expression of EMT markers (VIM, TWIST1, SNAI2) and decreased CDH1, which may contribute to their resistance to Tamoxifen. Treatment with the Wnt inhibitor, IWP-2 inhibited cell proliferation and markers of EMT. These data support the role of the Wnt signalling pathway in acquired resistance to Tamoxifen. Further research into the mechanism by which activated Wnt

  2. New advances of TMEM88 in cancer initiation and progression, with special emphasis on Wnt signaling pathway.

    Science.gov (United States)

    Ge, Yun-Xuan; Wang, Chang-Hui; Hu, Fu-Yong; Pan, Lin-Xin; Min, Jie; Niu, Kai-Yuan; Zhang, Lei; Li, Jun; Xu, Tao

    2018-01-01

    Transmembrane protein 88 (TMEM88), a newly discovered protein localized on the cell membrane. Recent studies showed that TMEM88 was involved in the regulation of several types of cancer. TMEM88 was expressed at significantly higher levels in breast cancer (BC) cell line than in normal breast cell line with co-localized with Dishevelled (DVL) in the cytoplasm of BC cell line. TMEM88 silencing in the ovarian cancer cell line CP70 resulted in significant upregulation of Wnt downstream genes (c-Myc, cyclin-D1) and other Wnt target genes including JUN, PTIX2, CTNNB1 (β-catenin), further supporting that TMEM88 inhibits canonical Wnt signaling pathway. Wnt signaling pathway has been known to play important roles in many diseases, especially in cancer. For instance, hepatocellular carcinoma (HCC) has become one of the most common tumors harboring mutations in the Wnt signaling pathway. As the inhibitor of Wnt signaling, TMEM88 has been considered to act as an oncogene or a tumor suppressor. Up-regulated TMEM88 or gene therapy approaches could be an effective therapeutic approach against tumor as TMEM88 inhibits Wnt signaling through direct interaction with DVL. Here, we review the current knowledge on the functional role and potential clinical application of TMEM88 in the control of various cancers. Highlights Wnt signaling displays an important role in several pathogenesis of cancer. Wnt signaling pathway is activated during cancer development. TMEM88 has an impact on cancer by inhibiting canonical Wnt signaling. We discuss the importance and new applications of TMEM88 in cancer therapy. © 2017 Wiley Periodicals, Inc.

  3. Peripheral T-lymphocytes express WNT7A and its restoration in leukemia-derived lymphoblasts inhibits cell proliferation

    International Nuclear Information System (INIS)

    Ochoa-Hernández, Alejandra B; Bravo-Cuellar, Alejandro; Jave-Suarez, Luis F; Barros-Núñez, Patricio; Aguilar-Lemarroy, Adriana; Ramos-Solano, Moisés; Meza-Canales, Ivan D; García-Castro, Beatriz; Rosales-Reynoso, Mónica A; Rosales-Aviña, Judith A; Barrera-Chairez, Esperanza; Ortíz-Lazareno, Pablo C; Hernández-Flores, Georgina

    2012-01-01

    WNT7a, a member of the Wnt ligand family implicated in several developmental processes, has also been reported to be dysregulated in some types of tumors; however, its function and implication in oncogenesis is poorly understood. Moreover, the expression of this gene and the role that it plays in the biology of blood cells remains unclear. In addition to determining the expression of the WNT7A gene in blood cells, in leukemia-derived cell lines, and in samples of patients with leukemia, the aim of this study was to seek the effect of this gene in proliferation. We analyzed peripheral blood mononuclear cells, sorted CD3 and CD19 cells, four leukemia-derived cell lines, and blood samples from 14 patients with Acute lymphoblastic leukemia (ALL), and 19 clinically healthy subjects. Reverse transcription followed by quantitative Real-time Polymerase chain reaction (qRT-PCR) analysis were performed to determine relative WNT7A expression. Restoration of WNT7a was done employing a lentiviral system and by using a recombinant human protein. Cell proliferation was measured by addition of WST-1 to cell cultures. WNT7a is mainly produced by CD3 T-lymphocytes, its expression decreases upon activation, and it is severely reduced in leukemia-derived cell lines, as well as in the blood samples of patients with ALL when compared with healthy controls (p ≤0.001). By restoring WNT7A expression in leukemia-derived cells, we were able to demonstrate that WNT7a inhibits cell growth. A similar effect was observed when a recombinant human WNT7a protein was used. Interestingly, restoration of WNT7A expression in Jurkat cells did not activate the canonical Wnt/β-catenin pathway. To our knowledge, this is the first report evidencing quantitatively decreased WNT7A levels in leukemia-derived cells and that WNT7A restoration in T-lymphocytes inhibits cell proliferation. In addition, our results also support the possible function of WNT7A as a tumor suppressor gene as well as a therapeutic

  4. 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.

  5. Eosinophils enhance WNT-5a and TGF-β1 genes expression in airway smooth muscle cells and promote their proliferation by increased extracellular matrix proteins production in asthma

    NARCIS (Netherlands)

    Januskevicius, Andrius; Vaitkiene, Simona; Gosens, Reinoud; Janulaityte, Ieva; Hoppenot, Deimante; Sakalauskas, Raimundas; Malakauskas, Kestutis

    2016-01-01

    BACKGROUND: Recent studies have suggested that eosinophils may have a direct effect on airway smooth muscle cells (ASMC), causing their proliferation in patients with asthma, but the precise mechanism of the interaction between these cells remains unknown. We propose that changes in Wnt signaling

  6. A Conditioned Medium of Umbilical Cord Mesenchymal Stem Cells Overexpressing Wnt7a Promotes Wound Repair and Regeneration of Hair Follicles in Mice

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    Liang Dong

    2017-01-01

    Full Text Available Mesenchymal stem cells (MSCs can affect the microenvironment of a wound and thereby accelerate wound healing. Wnt proteins act as key mediators of skin development and participate in the formation of skin appendages such as hair. The mechanisms of action of MSCs and Wnt proteins on skin wounds are largely unknown. Here, we prepared a Wnt7a-containing conditioned medium (Wnt-CM from the supernatant of cultured human umbilical cord-MSCs (UC-MSCs overexpressing Wnt7a in order to examine the effects of this CM on cutaneous healing. Our results revealed that Wnt-CM can accelerate wound closure and induce regeneration of hair follicles. Meanwhile, Wnt-CM enhanced expression of extracellular matrix (ECM components and cell migration of fibroblasts but inhibited the migratory ability and expression of K6 and K16 in keratinocytes by enhancing expression of c-Myc. However, we found that the CM of fibroblasts treated with Wnt-CM (HFWnt-CM-CM can also promote wound repair and keratinocyte migration; but there was no increase in the number of hair follicles of regeneration. These data indicate that Wnt7a and UC-MSCs have synergistic effects: they can accelerate wound repair and induce hair regeneration via cellular communication in the wound microenvironment. Thus, this study opens up new avenues of research on the mechanisms underlying wound repair.

  7. Paracrine Activation of the Wnt/β-Catenin Pathway by Bone Marrow Stem Cell Attenuates Cisplatin-Induced Kidney Injury

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    Xiaoyan Jiao

    2017-12-01

    Full Text Available Background/Aims: Cisplatin-induced acute kidney injury (AKI involves damage to tubular cells via excess reactive oxygen species (ROS generation. Stem cell-based therapies have shown great promise in AKI treatment. In this study, we aimed to assess the protective effect and mechanism of bone marrow mesenchymal stem cell (BMSC-derived conditioned medium (CM against cisplatin-induced AKI. Methods: In vitro, NRK-52E cells were incubated with cisplatin in the presence or absence of CM, followed by the assessment of cell viability, apoptosis and cell cycle distribution. Then, ICG-001 and IWR-1 were used to inhibit the wnt/β-catenin pathway. Furthermore, intracellular and mitochondrial ROS levels were evaluated using DCFH-DA and MitoSOX, respectively. In vivo, after cisplatin injection, rats were intravenously injected with CM or BMSCs. Sera and kidney tissues were collected on day 3 after cisplatin injection to evaluate changes in renal function and histology. Western blotting and qRT-PCR were employed to determine the expression of wnt/β-catenin pathway-related genes and proteins. Immunohistochemical staining was used to evaluate tubular β-catenin expression in kidney biopsy from AKI patients. Results: CM protected NRK-52E cells from cisplatin-induced injury by restoring the wnt4/β-catenin pathway. In response to ICG-001 and IWR-1, the protective effect of CM was attenuated, characterized by a decrease in cell proliferation and an increase in cell apoptosis and intracellular and mitochondrial ROS levels. Knockdown of β-catenin using siRNAs also suppressed the mitochondrial biogenesis regulators PGC-1α, TFAM and NRF-1. In the rat model, CM significantly alleviated renal function and histology associated with tubular injury and upregulated wnt4 and β-catenin. However, the renoprotective effect of CM was blocked by ICG-001, characterized by exacerbated renal function, suppressed PGC-1α expression and increased mitochondrial ROS. Clinical data

  8. Generation and propagation of radical reactions on proteins

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    2001-01-01

    The oxidation of proteins by free radicals is thought to play a major role in many oxidative processes within cells and is implicated in a number of human diseases as well as ageing. This review summarises information on the formation of radicals on peptides and proteins and how radical damage ma...

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

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    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.

  10. Canonical Wnt signaling maintains the quiescent stage of hepatic stellate cells

    International Nuclear Information System (INIS)

    Kordes, Claus; Sawitza, Iris; Haeussinger, Dieter

    2008-01-01

    It is well known that hepatic stellate cells (HSC) develop into cells, which are thought to contribute to liver fibrogenesis. Recent data suggest that HSC are progenitor cells with the capacity to differentiate into cells of endothelial and hepatocyte lineages. The present study shows that β-catenin-dependent canonical Wnt signaling is active in freshly isolated HSC of rats. Mimicking of the canonical Wnt pathway in cultured HSC by TWS119, an inhibitor of the glycogen synthase kinase 3β, led to reduced β-catenin phosphorylation, induced nuclear translocation of β-catenin, elevated glutamine synthetase production, impeded synthesis of α-smooth muscle actin and Wnt5a, but promoted the expression of glial fibrillary acidic protein, Wnt10b, and paired-like homeodomain transcription factor 2c. In addition, canonical Wnt signaling lowered DNA synthesis and hindered HSC from entering the cell cycle. The findings demonstrate that β-catenin-dependent Wnt signaling maintains the quiescent state of HSC and, similar to stem and progenitor cells, influences their developmental fate

  11. Lentiviral Modulation of Wnt/β-Catenin Signaling Affects In Vivo LTP.

    Science.gov (United States)

    Ivanova, Olga Ya; Dobryakova, Yulia V; Salozhin, Sergey V; Aniol, Viktor A; Onufriev, Mikhail V; Gulyaeva, Natalia V; Markevich, Vladimir A

    2017-10-01

    Wnt signaling is involved in hippocampal development and synaptogenesis. Numerous recent studies have been focused on the role of Wnt ligands in the regulation of synaptic plasticity. Inhibitors and activators of canonical Wnt signaling were demonstrated to decrease or increase, respectively, in vitro long-term potentiation (LTP) maintenance in hippocampal slices (Chen et al. in J Biol Chem 281:11910-11916, 2006; Vargas et al. in J Neurosci 34:2191-2202, 2014, Vargas et al. in Exp Neurol 264:14-25, 2015). Using lentiviral approach to down- and up-regulate the canonical Wnt signaling, we explored whether Wnt/β-catenin signaling is critical for the in vivo LTP. Chronic suppression of Wnt signaling induced an impairment of in vivo LTP expression 14 days after lentiviral suspension injection, while overexpression of Wnt3 was associated with a transient enhancement of in vivo LTP magnitude. Both effects were related to the early phase LTP and did not affect LTP maintenance. A loss-of-function study demonstrated decreased initial paired pulse facilitation ratio, β-catenin, and phGSK-3β levels. A gain-of-function study revealed not only an increase in PSD-95, β-catenin, and Cyclin D1 protein levels, but also a reduced phGSK-3β level and enhanced GSK-3β kinase activity. These results suggest a presynaptic dysfunction predominantly underlying LTP impairment while postsynaptic modifications are primarily involved in transient LTP amplification. This study is the first demonstration of the involvement of Wnt/β-catenin signaling in synaptic plasticity regulation in an in vivo LTP model.

  12. Modulating Wnt Signaling Rescues Palate Morphogenesis in Pax9 Mutant Mice.

    Science.gov (United States)

    Li, C; Lan, Y; Krumlauf, R; Jiang, R

    2017-10-01

    Cleft palate is a common birth defect caused by disruption of palatogenesis during embryonic development. Although mutations disrupting components of the Wnt signaling pathway have been associated with cleft lip and palate in humans and mice, the mechanisms involving canonical Wnt signaling and its regulation in secondary palate development are not well understood. Here, we report that canonical Wnt signaling plays an important role in Pax9-mediated regulation of secondary palate development. We found that cleft palate pathogenesis in Pax9-deficient embryos is accompanied by significantly reduced expression of Axin2, an endogenous target of canonical Wnt signaling, in the developing palatal mesenchyme, particularly in the posterior regions of the palatal shelves. We found that expression of Dkk2, encoding a secreted Wnt antagonist, is significantly increased whereas the levels of active β-catenin protein, the essential transcriptional coactivator of canonical Wnt signaling, is significantly decreased in the posterior regions of the palatal shelves in embryonic day 13.5 Pax9-deficent embryos in comparison with control littermates. We show that small molecule-mediated inhibition of Dickkopf (DKK) activity in utero during palatal shelf morphogenesis partly rescued secondary palate development in Pax9-deficient embryos. Moreover, we found that genetic inactivation of Wise, which is expressed in the developing palatal shelves and encodes another secreted antagonist of canonical Wnt signaling, also rescued palate morphogenesis in Pax9-deficient mice. Furthermore, whereas Pax9 del/del embryos exhibit defects in palatal shelf elevation/reorientation and significant reduction in accumulation of hyaluronic acid-a high molecular extracellular matrix glycosaminoglycan implicated in playing an important role in palatal shelf elevation-80% of Pax9 del/del ;Wise -/- double-mutant mouse embryos exhibit rescued palatal shelf elevation/reorientation, accompanied by restored

  13. High-frequency deregulated expression of Wnt signaling pathway members in breast carcinomas.

    Science.gov (United States)

    Khan, Zahid; Arafah, Maha; Shaik, Jilani Purusottapatnam; Mahale, Alka; Alanazi, Mohammad Saud

    2018-01-01

    Breast carcinoma is the most common malignancy and leading cause of cancer-related deaths in women worldwide including Saudi Arabia. Breast cancer in Saudi women develops at a much early age with median age of onset of 49 years compared to 62 years observed in patients from USA. Aberrations in wingless and integration site growth factor (Wnt) signaling pathway have been pathologically implicated in development of breast cancers and hence its role was examined in Saudi patients. We immunohistochemically examined various components of Wnt signaling pathway including β-catenin, tumor suppressor proteins, adenomatous polyposis coli (APC), and Axin, expression of naturally occurring pathway antagonists such as Dickkopf Wnt signaling pathway inhibitor 3 (DKK3), FRP2, and WIF1, as well as Wnt target cyclin D1 and c-Myc to establish if the pathway is constitutively activated in breast cancers arising in Saudi women. Cytoplasmic β-catenin, indicative of activation of the pathway, was observed in 24% of cases. Expression of APC and Axin, which are components of β-catenin destruction complex, was lost in 5% and 10% of tumors, respectively. Additionally, Wnt signaling inhibitors DKK3, FRP2, and Wnt inhibitory factor 1 (WIF1) were not expressed in 8%, 14%, and 5% breast tumors, respectively. Overall, accumulation of cytoplasmic β-catenin and downregulation of other Wnt pathway proteins (APC/Axin/DKK3/FRP2/WIF1) were found in approximately half of the breast cancers (47%) in our cohort. Consistent with this, analysis of Wnt target genes demonstrated moderate-to-strong expression of c-Myc in 58% and cyclin D1 in 50% of breast cancers. Deregulation of Wnt pathway was not associated with age of onset of the disease, tumor grade, and triple-negative status of breast cancers. High level of deregulated expression of Wnt pathway proteins suggests its important role in pathogenesis of breast cancers arising in Saudi women who may benefit from development of therapeutic drugs

  14. GSK-3β suppresses HCC cell dissociation in vitro by upregulating epithelial junction proteins and inhibiting Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Zhang, Jing-Hua; Jiao, Li-Yan; Li, Tie-Jun; Zhu, York Yuanyuan; Zhou, Jian-Wei; Tian, Jian

    2017-01-01

    Glycogen synthase kinase-3β (GSK-3β) is required in the expression of epithelial junction proteins. It was found downregulated in hepatocellular carcinoma (HCC) tissues. The purpose of this study was to investigate the role of GSK-3β in modulating the metastatic behaviors of human HCC cell lines in vitro . In this study, the expression level of GSK-3β was measured in 4 human HCC cell lines, and the small interfering RNA (siRNA) vectors against or plasmids encoding GSK-3β were used to evaluate the responses of target cells to the knockdown or overexpression of this kinase, respectively. Our results showed that GSK-3β expression was significantly lower in human HCC cell lines with high metastatic potential than that in HCC cell lines without metastatic characteristics or in a normal human liver cell line. The knockdown of GSK-3β by siRNA led to a decreased expression of the epithelial junction molecules (ZO-1, E-cadherin) and an increase in the expression of a mesenchymal cell marker (α-SMA) and a gene transcription factor (β-catenin), resulting in enhanced tumor cell dissemination. In contrast, gain-of-function studies revealed that ectopic expression of GSK-3β reduced invasive and migratory abilities of HCC cells accompanied by decreased HCC cell proliferation and induced apoptosis. More importantly, downregulation of GSK-3β led to an increase in the expression and accumulation of β-catenin in the nuclei, promoting gene transcription. In conclusion, GSK-3β might play a vital role in suppressing HCC dissociation by preventing the disassembly of cancer cell epithelial junctional complex via the GSK-3β/β-catenin pathway.

  15. The connections of Wnt pathway components with cell cycle and centrosome: side effects or a hidden logic?

    Science.gov (United States)

    Bryja, Vítězslav; Červenka, Igor; Čajánek, Lukáš

    2017-12-01

    Wnt signaling cascade has developed together with multicellularity to orchestrate the development and homeostasis of complex structures. Wnt pathway components - such as β-catenin, Dishevelled (DVL), Lrp6, and Axin-- are often dedicated proteins that emerged in evolution together with the Wnt signaling cascade and are believed to function primarily in the Wnt cascade. It is interesting to see that in recent literature many of these proteins are connected with cellular functions that are more ancient and not limited to multicellular organisms - such as cell cycle regulation, centrosome biology, or cell division. In this review, we summarize the recent literature describing this crosstalk. Specifically, we attempt to find the answers to the following questions: Is the response to Wnt ligands regulated by the cell cycle? Is the centrosome and/or cilium required to activate the Wnt pathway? How do Wnt pathway components regulate the centrosomal cycle and cilia formation and function? We critically review the evidence that describes how these connections are regulated and how they help to integrate cell-to-cell communication with the cell and the centrosomal cycle in order to achieve a fine-tuned, physiological response.

  16. Wnt signaling promotes androgen-independent prostate cancer cell proliferation through up-regulation of the hippo pathway effector YAP.

    Science.gov (United States)

    Seo, Won Ik; Park, Seoyoung; Gwak, Jungsug; Ju, Bong Gun; Chung, Jae Il; Kang, Pil Moon; Oh, Sangtaek

    2017-05-13

    Aberrant up-regulation of Wnt/β-catenin signaling is associated with the development and progression of prostate cancer, but the underlying mechanism is unclear. Here we show that in the absence of androgens, the Wnt/β-catenin pathway activates AR-mediated transcription through up-regulation of the Hippo pathway effector Yes-associated protein (YAP). Wnt3a-conditioned medium (Wnt3a-CM) promotes the growth of LNCaP cells and increases AR and YAP protein levels. Moreover, Wnt3a-CM induces the nuclear translocation of YAP and the AR, but not β-catenin, thereby activating the expression of AR- and YAP-dependent genes, in an androgen-independent manner. In addition, depletion of YAP with small interfering RNA (siRNA) prevented Wnt3a-CM-mediated up-regulation of AR-dependent gene expression. Thus, our findings provide mechanistic insight into the proposed cross-talk between the Wnt/β-catenin and Hippo pathways in androgen-independent prostate cancer development. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Pyrvinium, a potent small molecule Wnt inhibitor, promotes wound repair and post-MI cardiac remodeling.

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    Sarika Saraswati

    Full Text Available Wnt signaling plays an important role in developmental and stem cell biology. To test the hypothesis that temporary inhibition of Wnt signaling will enhance granulation tissue and promote angiogenesis in tissue repair, we employed a recently characterized small molecule Wnt inhibitor. Pyrvinium is an FDA-approved drug that we identified as a Wnt inhibitor in a chemical screen for small molecules that stabilize β-catenin and inhibit Axin degradation. Our subsequent characterization of pyrvinium has revealed that its critical cellular target in the Wnt pathway is Casein Kinase 1α. Daily administration of pyrvinium directly into polyvinyl alcohol (PVA sponges implanted subcutaneously in mice generated better organized and vascularized granulation tissue; this compound also increased the proliferative index of the tissue within the sponges. To evaluate its effect in myocardial repair, we induced a myocardial infarction (MI by coronary artery ligation and administered a single intramyocardial dose of pyrvinium. Mice were evaluated by echocardiography at 7 and 30 days post-MI and treatment; post mortem hearts were evaluated by histology at 30 days. Pyrvinium reduced adverse cardiac remodeling demonstrated by decreased left ventricular internal diameter in diastole (LVIDD as compared to a control compound. Increased Ki-67+ cells were observed in peri-infarct and distal myocardium of pyrvinium-treated animals. These results need to be further followed-up to determine if therapeutic inhibition of canonical Wnt may avert adverse remodeling after ischemic injury and its impact on myocardial repair and regeneration.

  18. Wnt/β-catenin Signaling in Osteoarthritis and in Other Forms of Arthritis.

    Science.gov (United States)

    Zhou, Yachuan; Wang, Tingyu; Hamilton, John L; Chen, Di

    2017-09-01

    Arthritis defines a large group of diseases primarily affecting the joint. It is the leading cause of pain and disability in adults. Osteoarthritis (OA) affecting the knee or hip is the most common form among over 100 types of arthritis. Other types of arthritis include erosive hand OA, temporomandibular joint (TMJ) OA, facet joint OA, diffuse idiopathic skeletal hyperostosis (DISH), and spondyloarthritis (SpA). However, the specific molecular signals involved in the development and progression of OA and related forms of arthritis remain largely unknown. The canonical wingless/integrated (Wnt)/β-catenin signaling pathway could play a unique role in the pathogenesis of arthritis. In this review article, we will focus on the molecular mechanisms of Wnt/β-catenin signaling in the pathogenesis of OA and other types of arthritis. Emerging evidence demonstrates that Wnts and Wnt-related molecules are involved in arthritis development and progression in human genetic studies and in vitro studies. Also, mouse models have been generated to determine the role of Wnt/β-catenin signaling in the pathogenesis of arthritis. Wnt/β-catenin signaling represents a unique signaling pathway regulating arthritis development and progression, and the molecules in this particular pathway may serve as targets for the therapeutic intervention of arthritis. Mediators and downstream effectors of Wnt/β-catenin signaling are increased in OA as well other forms of arthritis, including DISH and SpA. Through extensive investigations, including pre-clinical studies in transgenic mice and translational and human studies, the Wnt/β-catenin signaling pathway has been proven to play roles in bone and joint pathology by directly affecting bone, cartilage, and synovial tissue; further, these pathologies can be reduced through targeting this pathway. Continued investigation into the distinct molecular signaling of the Wnt/β-catenin pathway will provide additional insights toward the therapeutic

  19. Did Convergent Protein Evolution Enable Phytoplasmas to Generate 'Zombie Plants'?

    Science.gov (United States)

    Rümpler, Florian; Gramzow, Lydia; Theißen, Günter; Melzer, Rainer

    2015-12-01

    Phytoplasmas are pathogenic bacteria that reprogram plant development such that leaf-like structures instead of floral organs develop. Infected plants are sterile and mainly serve to propagate phytoplasmas and thus have been termed 'zombie plants'. The developmental reprogramming relies on specific interactions of the phytoplasma protein SAP54 with a small subset of MADS-domain transcription factors. Here, we propose that SAP54 folds into a structure that is similar to that of the K-domain, a protein-protein interaction domain of MADS-domain proteins. We suggest that undergoing convergent structural and sequence evolution, SAP54 evolved to mimic the K-domain. Given the high specificity of resulting developmental alterations, phytoplasmas might be used to study flower development in genetically intractable plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Transforming Growth Factor β Activation Primes Canonical Wnt Signaling Through Down-Regulation of Axin-2.

    Science.gov (United States)

    Gillespie, Justin; Ross, Rebecca L; Corinaldesi, Clarissa; Esteves, Filomena; Derrett-Smith, Emma; McDermott, Michael F; Doody, Gina M; Denton, Christopher P; Emery, Paul; Del Galdo, Francesco

    2018-02-06

    Aberrant activation of Wnt signaling has been observed in tissues from patients with systemic sclerosis (SSc). This study aimed to determine the role of transforming growth factor β (TGFβ) in driving the increased Wnt signaling, through modulation of axis inhibition protein 2 (Axin-2), a critical regulator of the Wnt canonical pathway. Canonical Wnt signaling activation was analyzed by TOPflash T cell factor/lymphoid enhancer factor promoter assays. Axin-2 was evaluated in vitro by analysis of Axin-2 primary/mature transcript expression and decay, TGFβ receptor type I (TGFβRI) blockade, small interfering RNA-mediated depletion of tristetraprolin 1, and XAV-939-mediated Axin-2 stabilization. In vivo, Axin-2 messenger RNA (mRNA) and protein expression was determined in skin and lung biopsy samples from mice that express a kinase-deficient TGFβRII specifically on fibroblasts (TβRIIΔk-fib-transgenic mice) and from littermate controls. SSc fibroblasts displayed an increased response to canonical Wnt ligands despite basal levels of Wnt signaling that were comparable to those in healthy control fibroblasts in vitro. Notably, we showed that SSc fibroblasts had reduced basal expression of Axin-2, which was caused by an endogenous TGFβ-dependent increase in Axin-2 mRNA decay. Accordingly, we observed that TGFβ decreased Axin-2 expression both in vitro in healthy control fibroblasts and in vivo in TβRIIΔk-fib-transgenic mice. Additionally, using Axin-2 gain- and loss-of-function experiments, we demonstrated that the TGFβ-induced increased response to Wnt activation characteristic of SSc fibroblasts depended on reduced bioavailability of Axin-2. This study highlights the importance of reduced bioavailability of Axin-2 in mediating the increased canonical Wnt response observed in SSc fibroblasts. This novel mechanism extends our understanding of the processes involved in Wnt/β-catenin-driven pathology and supports the rationale for targeting the TGFβ pathway

  1. The Netrin-related domain of Sfrp1 interacts with Wnt ligands and antagonizes their activity in the anterior neural plate

    Directory of Open Access Journals (Sweden)

    Esteve Pilar

    2008-08-01

    Full Text Available Abstract Background Secreted frizzled related proteins (SFRPs are multifunctional modulators of Wnt and BMP (Bone Morphogenetic Protein signalling necessary for the development of most organs and the homeostasis of different adult tissues. SFRPs fold in two independent domains: the cysteine rich domain (SfrpCRD related to the extracellular portion of Frizzled (Fz, Wnt receptors and the Netrin module (SfrpNTR defined by homologies with molecules such as Netrin-1, inhibitors of metalloproteinases and complement proteins. Due to its structural relationship with Fz, it is believed that SfrpCRD interferes with Wnt signalling by binding and sequestering the ligand. In contrast, the functional relevance of the SfrpNTR has been barely addressed. Results Here, we combine biochemical studies, mutational analysis and functional assays in cell culture and medaka-fish embryos to show that the Sfrp1NTR mimics the function of the entire molecule, binds to Wnt8 and antagonizes Wnt canonical signalling. This activity requires intact tertiary structure and is shared by the distantly related Netrin-1NTR. In contrast, the Sfrp1CRD cannot mirror the function of the entire molecule in vivo but interacts with Fz receptors and antagonizes Wnt8-mediated β-catenin transcriptional activity. Conclusion On the basis of these results, we propose that SFRP modulation of Wnt signalling may involve multiple and differential interactions among Wnt, Fz and SFRPs.

  2. Oncogenic homeodomain transcription factor E2A-Pbx1 activates a novel WNT gene in pre-B acute lymphoblastoid leukemia.

    Science.gov (United States)

    McWhirter, J R; Neuteboom, S T; Wancewicz, E V; Monia, B P; Downing, J R; Murre, C

    1999-09-28

    A large fraction of pediatric pre-B acute lymphoblastoid leukemias (ALL) consistently contain a t(1;19) chromosomal translocation. The t(1;19) translocation results in the production of a chimeric transcription factor containing the N-terminal transactivation domain of E2A fused to the C-terminal DNA-binding homeodomain of Pbx1. Here, we show that the E2A-Pbx1 fusion protein activates the expression of a novel WNT gene, WNT-16. WNT-16 normally is expressed in peripheral lymphoid organs such as spleen, appendix, and lymph nodes, but not in bone marrow. In contrast, high levels of WNT-16 transcripts are present in bone marrow and cell lines derived from pre-B ALL patients carrying the E2A-Pbx1 hybrid gene. Inhibition of E2A-Pbx1 expression leads to a significant decrease in WNT-16 mRNA levels, suggesting that WNT-16 is a downstream target of E2A-Pbx1. Three putative WNT receptors, FZ-2, FZ-3, and FZ-5, are expressed in cells of the B lineage, including pre-B ALL cells aberrantly expressing WNT-16. We propose that a WNT-16-mediated autocrine growth mechanism contributes to the development of t(1;19) pre-B ALL.

  3. LncRNAs in Secondary Hair Follicle of Cashmere Goat: Identification, Expression, and Their Regulatory Network in Wnt Signaling Pathway.

    Science.gov (United States)

    Bai, Wen L; Zhao, Su J; Wang, Ze Y; Zhu, Yu B; Dang, Yun L; Cong, Yu Y; Xue, Hui L; Wang, Wei; Deng, Liang; Guo, Dan; Wang, Shi Q; Zhu, Yan X; Yin, Rong H

    2018-07-03

    Long noncoding RNAs (lncRNAs) are a novel class of eukaryotic transcripts. They are thought to act as a critical regulator of protein-coding gene expression. Herein, we identified and characterized 13 putative lncRNAs from the expressed sequence tags from secondary hair follicle of Cashmere goat. Furthermore, we investigated their transcriptional pattern in secondary hair follicle of Liaoning Cashmere goat during telogen and anagen phases. Also, we generated intracellular regulatory networks of upregulated lncRNAs at anagen in Wnt signaling pathway based on bioinformatics analysis. The relative expression of six putative lncRNAs (lncRNA-599618, -599556, -599554, -599547, -599531, and -599509) at the anagen phase is significantly higher than that at telogen. Compared with anagen, the relative expression of four putative lncRNAs (lncRNA-599528, -599518, -599511, and -599497) was found to be significantly upregulated at telogen phase. The network generated showed that a rich and complex regulatory relationship of the putative lncRNAs and related miRNAs with their target genes in Wnt signaling pathway. Our results from the present study provided a foundation for further elucidating the functional and regulatory mechanisms of these putative lncRNAs in the development of secondary hair follicle and cashmere fiber growth of Cashmere goat.

  4. SFRP2 enhances the osteogenic differentiation of apical papilla stem cells by antagonizing the canonical WNT pathway.

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    Jin, Luyuan; Cao, Yu; Yu, Guoxia; Wang, Jinsong; Lin, Xiao; Ge, Lihua; Du, Juan; Wang, Liping; Diao, Shu; Lian, Xiaomeng; Wang, Songlin; Dong, Rui; Shan, Zhaochen

    2017-01-01

    Exploring the molecular mechanisms underlying directed differentiation is helpful in the development of clinical applications of mesenchymal stem cells (MSCs). Our previous study on dental tissue-derived MSCs demonstrated that secreted frizzled-related protein 2 (SFRP2), a Wnt inhibitor, could enhance osteogenic differentiation in stem cells from the apical papilla (SCAPs). However, how SFRP2 promotes osteogenic differentiation of dental tissue-derived MSCs remains unclear. In this study, we used SCAPs to investigate the underlying mechanisms. SCAPs were isolated from the apical papilla of immature third molars. Western blot and real-time RT-PCR were applied to detect the expression of β-catenin and Wnt target genes. Alizarin Red staining, quantitative calcium analysis, transwell cultures and in vivo transplantation experiments were used to study the osteogenic differentiation potential of SCAPs. SFRP2 inhibited canonical Wnt signaling by enhancing phosphorylation and decreasing the expression of nuclear β-catenin in vitro and in vivo . In addition, the target genes of the Wnt signaling pathway, AXIN2 (axin-related protein 2) and MMP7 (matrix metalloproteinase-7), were downregulated by SFRP2 . WNT1 inhibited the osteogenic differentiation potential of SCAPs. SFRP2 could rescue this WNT1 -impaired osteogenic differentiation potential. The results suggest that SFRP2 could bind to locally present Wnt ligands and alter the balance of intracellular Wnt signaling to antagonize the canonical Wnt pathway in SCAPs. This elucidates the molecular mechanism underlying the SFRP2-mediated directed differentiation of SCAPs and indicates potential target genes for improving dental tissue regeneration.

  5. 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.

  6. Wnt/β-catenin signaling is required for distraction osteogenesis in rats.

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    Wang, Xuemei; Luo, En; Bi, Ruiye; Ye, Bin; Hu, Jing; Zou, Shujuan

    2018-01-01

    The Wnt signaling pathway plays crucial roles in embryonic skeletal development and postnatal bone regeneration. However, mechanisms of Wnt signaling functioning in distraction osteogenesis (DO) haven't been well characterized. We established a DO model using Sprague-Dawley rat tibia. And a Wnt signaling blocking agent, recombinant rat Dickkopf-related protein 1 (rrDkk1), was locally applied in the distracted gap to study the role of Wnt signaling during DO process. Animals in the experimental group received rrDkk1 injections (dose = 25 μg/kg) once daily during distraction period and every third day during consolidation stage (n = 48). Animals in the control group received saline under the same injection strategy (n = 48). Animals at different time points during DO process (1, 3, 6, 12 days after distraction, 10 days and 6 weeks after consolidation) were killed and tissues in the distraction region were harvested for radiography, dual energy X-ray absorptiometry, micro-computed tomography (micro-CT), and histological analyses. Most Wnt ligands, cofactors, receptors, and antagonists were widely expressed in the distraction callus and were significantly upregulated during DO process. After rrDkk1 administration, the majority of these factors were downregulated at the mRNA level, except sFRP and GSK-3β. At the protein level, both β-catenin and Lef-1 were also suppressed by rrDkk1. In the long term, restricted bone healing was observed in the distracted callus in the rrDkk1 injection group. These findings were confirmed by histological and micro-CT analyses. Our findings suggest that Wnt signaling participates in the process of DO, and clinical therapeutic approaches of DO may do well to avoid Wnt pathway suppression.

  7. Aluminum Trichloride Inhibited Osteoblastic Proliferation and Downregulated the Wnt/β-Catenin Pathway.

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    Huang, Wanyue; Wang, Peiyan; Shen, Tongtong; Hu, Chongwei; Han, Yanfei; Song, Miao; Bian, Yu; Li, Yanfei; Zhu, Yanzhu

    2017-06-01

    Aluminum (Al) exposure inhibits bone formation. Osteoblastic proliferation promotes bone formation. Therefore, we inferred that Al may inhibit bone formation by the inhibition of osteoblastic proliferation. However, the effects and molecular mechanisms of Al on osteoblastic proliferation are still under investigation. Osteoblastic proliferation can be regulated by Wnt/β-catenin signaling pathway. To investigate the effects of Al on osteoblastic proliferation and whether Wnt/β-catenin signaling pathway is involved in it, osteoblasts from neonatal rats were cultured and exposed to 0, 0.4 mM (1/20 IC 50 ), 0.8 mM (1/10 IC 50 ), and 1.6 mM (1/5 IC 50 ) of aluminum trichloride (AlCl 3 ) for 24 h, respectively. The osteoblastic proliferation rates; Wnt3a, lipoprotein receptor-related protein 5 (LRP-5), T cell factor 1 (TCF-1), cyclin D1, and c-Myc messenger RNA (mRNA) expressions; and p-glycogen synthase kinase 3β (GSK3β), GSK3β, and β-catenin protein expressions indicated that AlCl 3 inhibited osteoblastic proliferation and downregulated Wnt/β-catenin signaling pathway. In addition, the AlCl 3 concentration was negatively correlated with osteoblastic proliferation rates and the mRNA expressions of Wnt3a, c-Myc, and cyclin D1, while the osteoblastic proliferation rates were positively correlated with mRNA expressions of Wnt3a, c-Myc, and cyclin D1. Taken together, these findings indicated that AlCl 3 inhibits osteoblastic proliferation may be associated with the inactivation of Wnt/β-catenin signaling pathway.

  8. Consequences of endogenous and exogenous WNT signaling for development of the preimplantation bovine embryo.

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    Tribulo, Paula; Leão, Beatriz Caetano da Silva; Lehloenya, Khoboso C; Mingoti, Gisele Zoccal; Hansen, Peter J

    2017-06-01

    The specific role of WNT signaling during preimplantation development remains unclear. Here, we evaluated consequences of activation and inhibition of β-catenin (CTNNB1)-dependent and -independent WNT signaling in the bovine preimplantation embryo. Activation of CTNNB1-mediated WNT signaling by the agonist 2-amino-4-(3,4-(methylenedioxy)benzylamino)-6-(3-methoxyphenyl)pyrimidine (AMBMP) and a glycogen synthase kinase 3 inhibitor reduced development to the blastocyst stage. Moreover, the antagonist of WNT signaling, dickkopf-related protein 1 (DKK1), alleviated the negative effect of AMBMP on development via reduction of CTNNB1. Based on labeling for phospho c-Jun N-terminal kinase, there was no evidence that DKK1 activated the planar cell polarity (PCP) pathway. Inhibition of secretion of endogenous WNTs did not affect development but increased number of cells in the inner cell mass (ICM). In contrast, DKK1 did not affect number of ICM or trophectoderm (TE) cells, suggesting that embryo-derived WNTs regulate ICM proliferation through a mechanism independent of CTNNB1. In addition, DKK1 did not affect the number of cells positive for the transcription factor yes-associated protein 1 (YAP1) involved in TE formation. In fact, DKK1 decreased YAP1. In contrast, exposure of embryos to WNT family member 7A (WNT7A) improved blastocyst development, inhibited the PCP pathway, and did not affect amounts of CTNNB1. Results indicate that embryo-derived WNTs are dispensable for blastocyst formation but participate in regulation of ICM proliferation, likely through a mechanism independent of CTNNB1. The response to AMBMP and WNT7A leads to the hypothesis that maternally derived WNTs can play a positive or negative role in regulation of preimplantation development. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction.

  9. Wnt Signaling in Skeletal Muscle Development and Regeneration.

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    Girardi, Francesco; Le Grand, Fabien

    2018-01-01

    Wnt is a family of signaling molecules involved in embryogenesis, adult tissue repair, and cancer. They activate canonical and noncanonical Wnt signaling cascades in target cells. Several studies, within the last decades, showed that several Wnt ligands are involved in myogenesis and both canonical and noncanonical Wnt pathways regulate muscle formation and the maintenance of adult tissue homeostasis. In this review, we provide a comprehensive overview of the roles of Wnt signaling during muscle development and an updated description of Wnt functions during muscle repair. Lastly, we discuss the crosstalk between Wnt and TGFβ signaling pathways in skeletal muscle. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Exploiting the WNT Signaling Pathway for Clinical Purposes.

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    Johnson, Mark L; Recker, Robert R

    2017-06-01

    The goal of this paper is to evaluate critically the literature published over the past 3 years regarding the Wnt signaling pathway. The Wnt pathway was found to be involved in bone biology in 2001-2002 with the discovery of a (G171V) mutation in the lipoprotein receptor-related protein 5 (LRP5) that resulted in high bone mass and another mutation that completely inactivated Lrp5 function and resulted in osteoporosis pseudoglioma syndrome (OPPG). The molecular biology has been complex, and very interesting. It has provided many opportunities for exploitation to develop new clinical treatments, particularly for osteoporosis. More clinical possibilities include: treatments for fracture healing, corticosteroid osteoporosis, osteogenesis imperfecta, and others. In addition, we wish to provide historical information coming from distant publications (~350 years ago) regarding bone biology that have been confirmed by study of Wnt signaling. A recent finding is the development of an antibody to sclerostin that is under study as a treatment for osteoporosis. Development of treatments for other forms of osteoporosis, such as corticosteroid osteoporosis, is also underway. The full range of the applications of the work is not yet been achieved.

  11. Runx expression is mitogenic and mutually linked to Wnt activity in blastula-stage sea urchin embryos.

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    Anthony J Robertson

    Full Text Available The Runt homology domain (Runx defines a metazoan family of sequence-specific transcriptional regulatory proteins that are critical for animal development and causally associated with a variety of mammalian cancers. The sea urchin Runx gene SpRunt-1 is expressed throughout the blastula stage embryo, and is required globally during embryogenesis for cell survival and differentiation.Depletion of SpRunt-1 by morpholino antisense-mediated knockdown causes a blastula stage deficit in cell proliferation, as shown by bromodeoxyuridine (BrdU incorporation and direct cell counts. Reverse transcription coupled polymerase chain reaction (RT-PCR studies show that the cell proliferation deficit is presaged by a deficit in the expression of several zygotic wnt genes, including wnt8, a key regulator of endomesoderm development. In addition, SpRunt-1-depleted blastulae underexpress cyclinD, an effector of mitogenic Wnt signaling. Blastula stage cell proliferation is also impeded by knockdown of either wnt8 or cyclinD. Chromatin immunoprecipitation (ChIP indicates that Runx target sites within 5' sequences flanking cyclinD, wnt6 and wnt8 are directly bound by SpRunt-1 protein at late blastula stage. Furthermore, experiments using a green fluorescent protein (GFP reporter transgene show that the blastula-stage operation of a cis-regulatory module previously shown to be required for wnt8 expression (Minokawa et al., Dev. Biol. 288: 545-558, 2005 is dependent on its direct sequence-specific interaction with SpRunt-1. Finally, inhibitor studies and immunoblot analysis show that SpRunt-1 protein levels are negatively regulated by glycogen synthase kinase (GSK-3.These results suggest that Runx expression and Wnt signaling are mutually linked in a feedback circuit that controls cell proliferation during development.

  12. Roles of Wnt/β-catenin signaling in epithelial differentiation of mesenchymal stem cells

    International Nuclear Information System (INIS)

    Wang, Yajing; Sun, Zhaorui; Qiu, Xuefeng; Li, Yan; Qin, Jizheng; Han, Xiaodong

    2009-01-01

    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/β-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/β-catenin signaling were determined, suggested down-regulation of Wnt/β-catenin with epithelial differentiation of MSCs. Furthermore, Wnt3α can inhibit the epithelial differentiation of MSCs. A loss of β-catenin induced by Dickkopf-1 can enhance MSCs differentiation into epithelial cells. Lithium chloride transiently activated β-catenin expression and subsequently decreased β-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/β-catenin signaling may promote MSCs to differentiate towards airway epithelial cells.

  13. 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.

  14. Dissecting molecular differences between Wnt coreceptors LRP5 and LRP6.

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    Bryan T MacDonald

    Full Text Available Low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and LRP6 serve as Wnt co-receptors for the canonical β-catenin pathway. While LRP6 is essential for embryogenesis, both LRP5 and LRP6 play critical roles for skeletal remodeling, osteoporosis pathogenesis and cancer formation, making LRP5 and LRP6 key therapeutic targets for cancer and disease treatment. LRP5 and LRP6 each contain in the cytoplasmic domain five conserved PPPSPxS motifs that are pivotal for signaling and serve collectively as phosphorylation-dependent docking sites for the scaffolding protein Axin. However existing data suggest that LRP6 is more effective than LRP5 in transducing the Wnt signal. To understand the molecular basis that accounts for the different signaling activity of LRP5 and LRP6, we generated a series of chimeric receptors via swapping LRP5 and LRP6 cytoplasmic domains, LRP5C and LRP6C, and studied their Wnt signaling activity using biochemical and functional assays. We demonstrate that LRP6C exhibits strong signaling activity while LRP5C is much less active in cells. Recombinant LRP5C and LRP6C upon in vitro phosphorylation exhibit similar Axin-binding capability, suggesting that LRP5 and LRP6 differ in vivo at a step prior to Axin-binding, likely at receiving phosphorylation. We identified between the two most carboxyl PPPSPxS motifs an intervening "gap4" region that appears to account for much of the difference between LRP5C and LRP6C, and showed that alterations in this region are sufficient to enhance LRP5 PPPSPxS phosphorylation and signaling to levels comparable to LRP6 in cells. In addition we provide evidence that binding of phosphorylated LRP5 or LRP6 to Axin is likely direct and does not require the GSK3 kinase as a bridging intermediate as has been proposed. Our studies therefore uncover a new and important molecular tuning mechanism for differential regulation of LRP5 and LRP6 phosphorylation and signaling activity.

  15. Dissecting molecular differences between Wnt coreceptors LRP5 and LRP6.

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    MacDonald, Bryan T; Semenov, Mikhail V; Huang, He; He, Xi

    2011-01-01

    Low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and LRP6) serve as Wnt co-receptors for the canonical β-catenin pathway. While LRP6 is essential for embryogenesis, both LRP5 and LRP6 play critical roles for skeletal remodeling, osteoporosis pathogenesis and cancer formation, making LRP5 and LRP6 key therapeutic targets for cancer and disease treatment. LRP5 and LRP6 each contain in the cytoplasmic domain five conserved PPPSPxS motifs that are pivotal for signaling and serve collectively as phosphorylation-dependent docking sites for the scaffolding protein Axin. However existing data suggest that LRP6 is more effective than LRP5 in transducing the Wnt signal. To understand the molecular basis that accounts for the different signaling activity of LRP5 and LRP6, we generated a series of chimeric receptors via swapping LRP5 and LRP6 cytoplasmic domains, LRP5C and LRP6C, and studied their Wnt signaling activity using biochemical and functional assays. We demonstrate that LRP6C exhibits strong signaling activity while LRP5C is much less active in cells. Recombinant LRP5C and LRP6C upon in vitro phosphorylation exhibit similar Axin-binding capability, suggesting that LRP5 and LRP6 differ in vivo at a step prior to Axin-binding, likely at receiving phosphorylation. We identified between the two most carboxyl PPPSPxS motifs an intervening "gap4" region that appears to account for much of the difference between LRP5C and LRP6C, and showed that alterations in this region are sufficient to enhance LRP5 PPPSPxS phosphorylation and signaling to levels comparable to LRP6 in cells. In addition we provide evidence that binding of phosphorylated LRP5 or LRP6 to Axin is likely direct and does not require the GSK3 kinase as a bridging intermediate as has been proposed. Our studies therefore uncover a new and important molecular tuning mechanism for differential regulation of LRP5 and LRP6 phosphorylation and signaling activity.

  16. The function of endocytosis in Wnt signaling.

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    Brunt, Lucy; Scholpp, Steffen

    2018-03-01

    Wnt growth factors regulate one of the most important signaling networks during development, tissue homeostasis and disease. Despite the biological importance of Wnt signaling, the mechanism of endocytosis during this process is ill described. Wnt molecules can act as paracrine signals, which are secreted from the producing cells and transported through neighboring tissue to activate signaling in target cells. Endocytosis of the ligand is important at several stages of action: One central function of endocytic trafficking in the Wnt pathway occurs in the source cell. Furthermore, the β-catenin-dependent Wnt ligands require endocytosis for signal activation and to regulate gene transcription in the responding cells. Alternatively, Wnt/β-catenin-independent signaling regulates endocytosis of cell adherence plaques to control cell migration. In this comparative review, we elucidate these three fundamental interconnected functions, which together regulate cellular fate and cellular behavior. Based on established hypotheses and recent findings, we develop a revised picture for the complex function of endocytosis in the Wnt signaling network.

  17. Tiam1 Regulates the Wnt/Dvl/Rac1 Signaling Pathway and the Differentiation of Midbrain Dopaminergic Neurons

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    Čajánek, Lukáš; Ganji, Ranjani Sri; Henriques-Oliveira, Catarina; Theofilopoulos, Spyridon; Koník, Peter

    2013-01-01

    Understanding the mechanisms that drive the differentiation of dopaminergic (DA) neurons is crucial for successful development of novel therapies for Parkinson's disease, in which DA neurons progressively degenerate. However, the mechanisms underlying the differentiation-promoting effects of Wnt5a on DA precursors are poorly understood. Here, we present the molecular and functional characterization of a signaling pathway downstream of Wnt5a, the Wnt/Dvl/Rac1 pathway. First, we characterize the interaction between Rac1 and Dvl and identify the N-terminal part of Dvl3 as necessary for Rac1 binding. Next, we show that Tiam1, a Rac1 guanosine exchange factor (GEF), is expressed in the ventral midbrain, interacts with Dvl, facilitates Dvl-Rac1 interaction, and is required for Dvl- or Wnt5a-induced activation of Rac1. Moreover, we show that Wnt5a promotes whereas casein kinase 1 (CK1), a negative regulator of the Wnt/Dvl/Rac1 pathway, abolishes the interactions between Dvl and Tiam1. Finally, using ventral midbrain neurosphere cultures, we demonstrate that the generation of DA neurons in culture is impaired after Tiam1 knockdown, indicating that Tiam1 is required for midbrain DA differentiation. In summary, our data identify Tiam1 as a novel regulator of DA neuron development and as a Dvl-associated and Rac1-specific GEF acting in the Wnt/Dvl/Rac1 pathway. PMID:23109420

  18. Wnt signaling positively regulates endothelial cell fate specification in the Fli1a-positive progenitor population via Lef1.

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    Hübner, Kathleen; Grassme, Kathrin S; Rao, Jyoti; Wenke, Nina K; Zimmer, Cordula L; Korte, Laura; Mu Ller, Katja; Sumanas, Saulius; Greber, Boris; Herzog, Wiebke

    2017-10-01

    During vertebrate embryogenesis, vascular endothelial cells (ECs) and primitive erythrocytes become specified within close proximity in the posterior lateral plate mesoderm (LPM) from a common progenitor. However, the signaling cascades regulating the specification into either lineage remain largely elusive. Here, we analyze the contribution of β-catenin dependent Wnt signaling to EC and erythrocyte specification during zebrafish embryogenesis. We generated novel β-catenin dependent Wnt signaling reporters which, by using destabilized fluorophores (Venus-Pest, dGFP), specifically allow us to detect Wnt signaling responses in narrow time windows as well as in spatially restricted domains, defined by Cre recombinase expression (Tg(axin2 BAC :Venus-Pest) mu288 ; Tg(14TCF:loxP-STOP-loxP-dGFP) mu202 ). We therefore can detect β-catenin dependent Wnt signaling activity in a subset of the Fli1a-positive progenitor population. Additionally, we show that mesodermal Wnt3a-mediated signaling via the transcription factor Lef1 positively regulates EC specification (defined by kdrl expression) at the expense of primitive erythrocyte specification (defined by gata1 expression) in zebrafish embryos. Using mesoderm derived from human embryonic stem cells, we identified the same principle of Wnt signaling dependent EC specification in conjunction with auto-upregulation of LEF1. Our data indicate a novel role of β-catenin dependent Wnt signaling in regulating EC specification during vasculogenesis. Copyright © 2017. Published by Elsevier Inc.

  19. 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.

  20. Polymorphisms in WNT6 and WNT10A and colorectal adenoma risk.

    Science.gov (United States)

    Galbraith, Rachel L; Poole, Elizabeth M; Duggan, David; Muehling, Jill; Hsu, Li; Makar, Karen; Xiao, Liren; Potter, John D; Ulrich, Cornelia M

    2011-01-01

    The WNT/β-catenin signaling pathway upregulates transcription of genes involved in cell proliferation and cancer progression; it has been implicated in colorectal adenoma formation. To date, no studies have examined polymorphisms in WNT genes or WNT gene-environment interactions in relation to adenoma risk. Within a colonoscopy-based case-control study of 628 adenoma cases and 516 polyp-free controls, we analyzed two tagSNPs in WNT6 (rs6747776 G > C, rs6754599 G > C) and WNT10A (rs7349332 G > A, rs10177996 A > G). The WNT6 rs6747776 homozygous minor allele (CC) was associated with increased risk of colorectal adenoma (OR = 2.75, 95% CI: 1.03-7.31). We observed a statistically significant interaction between WNT6 rs6747776 and the proportion of calories from total fat (P-int = 0.02), where the highest risk was observed among those with minor alleles and lowest fat intake. We also detected a marginally significant (0.05 < P ≤ 0.10) interaction with fish intake (P-int = 0.09). Additionally, a marginally significant interaction was observed between proportion of calories from saturated fat and the WNT10A rs7349332 polymorphism. Our results suggest that genetic variability in the WNT pathway may play a role in colorectal adenoma formation or may partly mediate the increased risk of colorectal cancer associated with fat intake.

  1. Involvement of and interaction between WNT10A and EDA mutations in tooth agenesis cases in the Chinese population.

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    He, Huiying; Han, Dong; Feng, Hailan; Qu, Hong; Song, Shujuan; Bai, Baojing; Zhang, Zhenting

    2013-01-01

    Dental agenesis is the most common, often heritable, developmental anomaly in humans. Although WNT10A gene mutations are known to cause rare syndromes associated with tooth agenesis, including onycho-odontodermal dysplasia (OODD), Schöpf-Schulz-Passarge syndrome (SSPS), hypohidrotic ectodermal dysplasia (HED), and more than half of the cases of isolated oligodontia recently, the genotype-phenotype correlations and the mode of inheritance of WNT10A mutations remain unclear. The phenotypic expression with WNT10A mutations shows a high degree of variability, suggesting that other genes might function with WNT10A in regulating ectodermal organ development. Moreover, the involvement of mutations in other genes, such as EDA, which is also associated with HED and isolated tooth agenesis, is not clear. Therefore, we hypothesized that EDA mutations interact with WNT10A mutations to play a role in tooth agenesis. Additionally, EDA, EDAR, and EDARADD encode signaling molecules in the Eda/Edar/NF-κB signaling pathways, we also checked EDAR and EDARADD in this study. WNT10A, EDA, EDAR and EDARADD were sequenced in 88 patients with isolated oligodontia and 26 patients with syndromic tooth agenesis. The structure of two mutated WNT10A and two mutated EDA proteins was analyzed. Digenic mutations of both WNT10A and EDA were identified in 2 of 88 (2.27%) isolated oligodontia cases and 4 of 26 (15.38%) syndromic tooth agenesis cases. No mutation in EDAR or EDARADD gene was found. WNT10A and EDA digenic mutations could result in oligodontia and syndromic tooth agenesis in the Chinese population. Moreover, our results will greatly expand the genotypic spectrum of tooth agenesis.

  2. Involvement of and interaction between WNT10A and EDA mutations in tooth agenesis cases in the Chinese population.

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    Huiying He

    Full Text Available BACKGROUND: Dental agenesis is the most common, often heritable, developmental anomaly in humans. Although WNT10A gene mutations are known to cause rare syndromes associated with tooth agenesis, including onycho-odontodermal dysplasia (OODD, Schöpf-Schulz-Passarge syndrome (SSPS, hypohidrotic ectodermal dysplasia (HED, and more than half of the cases of isolated oligodontia recently, the genotype-phenotype correlations and the mode of inheritance of WNT10A mutations remain unclear. The phenotypic expression with WNT10A mutations shows a high degree of variability, suggesting that other genes might function with WNT10A in regulating ectodermal organ development. Moreover, the involvement of mutations in other genes, such as EDA, which is also associated with HED and isolated tooth agenesis, is not clear. Therefore, we hypothesized that EDA mutations interact with WNT10A mutations to play a role in tooth agenesis. Additionally, EDA, EDAR, and EDARADD encode signaling molecules in the Eda/Edar/NF-κB signaling pathways, we also checked EDAR and EDARADD in this study. METHODS: WNT10A, EDA, EDAR and EDARADD were sequenced in 88 patients with isolated oligodontia and 26 patients with syndromic tooth agenesis. The structure of two mutated WNT10A and two mutated EDA proteins was analyzed. RESULTS: Digenic mutations of both WNT10A and EDA were identified in 2 of 88 (2.27% isolated oligodontia cases and 4 of 26 (15.38% syndromic tooth agenesis cases. No mutation in EDAR or EDARADD gene was found. CONCLUSIONS: WNT10A and EDA digenic mutations could result in oligodontia and syndromic tooth agenesis in the Chinese population. Moreover, our results will greatly expand the genotypic spectrum of tooth agenesis.

  3. Wnt/β-catenin pathway regulates ABCB1 transcription in chronic myeloid leukemia

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    Corrêa Stephany

    2012-07-01

    Full Text Available Abstract Background The advanced phases of chronic myeloid leukemia (CML are known to be more resistant to therapy. This resistance has been associated with the overexpression of ABCB1, which gives rise to the multidrug resistance (MDR phenomenon. MDR is characterized by resistance to nonrelated drugs, and P-glycoprotein (encoded by ABCB1 has been implicated as the major cause of its emergence. Wnt signaling has been demonstrated to be important in several aspects of CML. Recently, Wnt signaling was linked to ABCB1 regulation through its canonical pathway, which is mediated by β-catenin, in other types of cancer. In this study, we investigated the involvement of the Wnt/β-catenin pathway in the regulation of ABCB1 transcription in CML, as the basal promoter of ABCB1 has several β-catenin binding sites. β-catenin is the mediator of canonical Wnt signaling, which is important for CML progression. Methods In this work we used the K562 cell line and its derived MDR-resistant cell line Lucena (K562/VCR as CML study models. Real time PCR (RT-qPCR, electrophoretic mobility shift assay (EMSA, chromatin immunoprecipitation (ChIP, flow cytometry (FACS, western blot, immunofluorescence, RNA knockdown (siRNA and Luciferase reporter approaches were used. Results β-catenin was present in the protein complex on the basal promoter of ABCB1 in both cell lines in vitro, but its binding was more pronounced in the resistant cell line in vivo. Lucena cells also exhibited higher β-catenin levels compared to its parental cell line. Wnt1 and β-catenin depletion and overexpression of nuclear β-catenin, together with TCF binding sites activation demonstrated that ABCB1 is positively regulated by the canonical pathway of Wnt signaling. Conclusions These results suggest, for the first time, that the Wnt/β-catenin pathway regulates ABCB1 in CML.

  4. Wnt/β-catenin pathway regulates ABCB1 transcription in chronic myeloid leukemia

    International Nuclear Information System (INIS)

    Corrêa, Stephany; Binato, Renata; Du Rocher, Bárbara; Castelo-Branco, Morgana TL; Pizzatti, Luciana; Abdelhay, Eliana

    2012-01-01

    The advanced phases of chronic myeloid leukemia (CML) are known to be more resistant to therapy. This resistance has been associated with the overexpression of ABCB1, which gives rise to the multidrug resistance (MDR) phenomenon. MDR is characterized by resistance to nonrelated drugs, and P-glycoprotein (encoded by ABCB1) has been implicated as the major cause of its emergence. Wnt signaling has been demonstrated to be important in several aspects of CML. Recently, Wnt signaling was linked to ABCB1 regulation through its canonical pathway, which is mediated by β-catenin, in other types of cancer. In this study, we investigated the involvement of the Wnt/β-catenin pathway in the regulation of ABCB1 transcription in CML, as the basal promoter of ABCB1 has several β-catenin binding sites. β-catenin is the mediator of canonical Wnt signaling, which is important for CML progression. In this work we used the K562 cell line and its derived MDR-resistant cell line Lucena (K562/VCR) as CML study models. Real time PCR (RT-qPCR), electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), flow cytometry (FACS), western blot, immunofluorescence, RNA knockdown (siRNA) and Luciferase reporter approaches were used. β-catenin was present in the protein complex on the basal promoter of ABCB1 in both cell lines in vitro, but its binding was more pronounced in the resistant cell line in vivo. Lucena cells also exhibited higher β-catenin levels compared to its parental cell line. Wnt1 and β-catenin depletion and overexpression of nuclear β-catenin, together with TCF binding sites activation demonstrated that ABCB1 is positively regulated by the canonical pathway of Wnt signaling. These results suggest, for the first time, that the Wnt/β-catenin pathway regulates ABCB1 in CML

  5. Crosstalk between long non-coding RNAs and Wnt/β-catenin signalling in cancer.

    Science.gov (United States)

    Yang, Gang; Shen, Tianyi; Yi, Xiaoming; Zhang, Zhengyu; Tang, Chaopeng; Wang, Longxin; Zhou, Yulin; Zhou, Wenquan

    2018-04-01

    Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts in the human genome which perform crucial functions in diverse biological processes. The abnormal expression of some lncRNAs has been found in tumorigenesis, development and therapy resistance of cancers. They may act as oncogenes or tumour suppressors and can be used as diagnostic or prognostic markers, prompting their therapeutic potentials in cancer treatments. Studies have indicated that many lncRNAs are involved in the regulation of several signal pathways, including Wnt/β-catenin signalling pathway, which has been reported to play a significant role in regulating embryogenesis, cell proliferation and controlling tumour biology. Emerging evidences have suggested that lncRNAs can interact with several components of the Wnt/β-catenin signalling pathway to regulate the expression of Wnt target genes in cancer. Moreover, the expression of lncRNAs can also be influenced by the pathway. Nevertheless, Wnt/β-catenin signalling pathway-related lncRNAs and their interactions in cancer are not systematically analysed before. Considering these, this review emphasized the associations between lncRNAs and Wnt/β-catenin signalling pathway in cancer initiation, progression and their therapeutic influence. We also provided an overview on characteristics of lncRNAs and Wnt/β-catenin signalling pathway and discussed their functions in tumour biology. Finally, targeting lncRNAs or/and molecules associated with the Wnt/β-catenin signalling pathway may be a feasible therapeutic method in the future. © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  6. The human PKP2/plakophilin-2 gene is induced by Wnt/β-catenin in normal and colon cancer-associated fibroblasts.

    Science.gov (United States)

    Niell, Núria; Larriba, María Jesús; Ferrer-Mayorga, Gemma; Sánchez-Pérez, Isabel; Cantero, Ramón; Real, Francisco X; Del Peso, Luis; Muñoz, Alberto; González-Sancho, José Manuel

    2018-02-15

    Colorectal cancer results from the malignant transformation of colonic epithelial cells. Stromal fibroblasts are the main component of the tumour microenvironment, and play an important role in the progression of this and other neoplasias. Wnt/β-catenin signalling is essential for colon homeostasis, but aberrant, constitutive activation of this pathway is a hallmark of colorectal cancer. Here we present the first transcriptomic study on the effect of a Wnt factor on human colonic myofibroblasts. Wnt3A regulates the expression of 1,136 genes, of which 662 are upregulated and 474 are downregulated in CCD-18Co cells. A set of genes encoding inhibitors of the Wnt/β-catenin pathway stand out among those induced by Wnt3A, which suggests that there is a feedback inhibitory mechanism. We also show that the PKP2 gene encoding the desmosomal protein Plakophilin-2 is a novel direct transcriptional target of Wnt/β-catenin in normal and colon cancer-associated fibroblasts. PKP2 is induced by β-catenin/TCF through three binding sites in the gene promoter and one additional binding site located in an enhancer 20 kb upstream from the transcription start site. Moreover, Plakophilin-2 antagonizes Wnt/β-catenin transcriptional activity in HEK-293T cells, which suggests that it may act as an intracellular inhibitor of the Wnt/β-catenin pathway. Our results demonstrate that stromal fibroblasts respond to canonical Wnt signalling and that Plakophilin-2 plays a role in the feedback control of this effect suggesting that the response to Wnt factors in the stroma may modulate Wnt activity in the tumour cells. © 2017 The Authors International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.

  7. Wnt5a enhances the response of CML cells to Imatinib Mesylate through JNK activation and γ-catenin inhibition.

    Science.gov (United States)

    Niu, Chang-Chun; Zhao, Chen; Zhang, Xiao-Li; Pan, Jing; Zhao, Chen; Wu, Wei-Ru; Li, Zhi-Qiang; Liu, Tao; Yang, Zhong; Si, Wei-Ke

    2013-11-01

    Imatinib Mesylate is widely used for the treatment of chronic myelogenous leukaemia (CML), and its effects on CML cells are influenced by several signalling proteins. The research is aimed at determining whether Wnt5a affects the effects of Imatinib Mesylate against BCR-ABL positive CML cells (K562 cells and KU812 cells) and which signalling proteins are involved in. The results showed that Wnt5a augmented the effects of Imatinib Mesylate on inhibiting CML cells proliferation and inducing apoptosis in vitro; Wnt5a enhanced the inhibition effect of Imatinib Mesylate on the growth of K562 cells xenograft tumour in an animal model. Furthermore, Wnt5a inhibited β-catenin and its target gene Survivin, increased the activity of JNK and suppressed γ-catenin expression. When inhibiting the activity of JNK, the influence of Wnt5a on the effects of Imatinib Mesylate was attenuated. Moreover, JNK suppressed β-catenin and its target gene Survivin, and enhanced the effects of Imatinib Mesylate. These results suggest that Wnt5a can enhance the efficacy of Imatinib Mesylate through JNK/β-catenin/Survivin and γ-catenin/β-catenin/Survivin pathways. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Uncovering Wnt signaling mechanisms in control of cell migration in C. elegans

    NARCIS (Netherlands)

    Mentink, R.A.

    2014-01-01

    Morphogens such as Wnt proteins play a central role in embryonic patterning by providing positional information to cells in developing tissues. In recent years, it has become clear that such morphogenic gradients also contribute to the guidance of migrating cells and axons in the developing nervous

  9. Canonical WNT Signalling Controls Hair Follicle Spacing

    OpenAIRE

    Schlake, Thomas; Sick, Stefanie

    2007-01-01

    Canonical WNT signals play an important role in hair follicle development. In addition to being crucial for epidermal appendage initiation, they control the interfollicular spacing pattern and contribute to the spatial orientation and largely parallel alignment of hair follicles. However, owing to the complexity of canonical WNT signalling and its interconnections with other pathways, many details of hair follicle formation await further clarification. Here, we discuss the recently suggested ...

  10. Control of osteogenesis by the canonical Wnt and BMP pathways in vivo: cooperation and antagonism between the canonical Wnt and BMP pathways as cells differentiate from osteochondroprogenitors to osteoblasts and osteocytes.

    Science.gov (United States)

    Marcellini, Sylvain; Henriquez, Juan Pablo; Bertin, Ariana

    2012-11-01

    Although many regulators of skeletogenesis have been functionally characterized, one current challenge is to integrate this information into regulatory networks. Here, we discuss how the canonical Wnt and Smad-dependent BMP pathways interact together and play antagonistic or cooperative roles at different steps of osteogenesis, in the context of the developing vertebrate embryo. Early on, BMP signaling specifies multipotent mesenchymal cells into osteochondroprogenitors. In turn, the function of Wnt signaling is to drive these osteochondroprogenitors towards an osteoblastic fate. Subsequently, both pathways promote osteoblast differentiation, albeit with notable mechanistic differences. In osteocytes, the ultimate stage of osteogenic differentiation, the Wnt and BMP pathways exert opposite effects on the control of bone resorption by osteoclasts. We describe how the dynamic molecular wiring of the canonical Wnt and Smad-dependent BMP signaling into the skeletal cell genetic programme is critical for the generation of bone-specific cell types during development. Copyright © 2012 WILEY Periodicals, Inc.

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

    Directory of Open Access Journals (Sweden)

    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. Wnt signaling in ovarian development inhibits Sf1 activation of Sox9 via the Tesco enhancer.

    Science.gov (United States)

    Bernard, Pascal; Ryan, Janelle; Sim, Helena; Czech, Daniel P; Sinclair, Andrew H; Koopman, Peter; Harley, Vincent R

    2012-02-01

    Genome analysis of patients with disorders of sex development, and gain- and loss-of-function studies in mice indicate that gonadal development is regulated by opposing signals. In females, the Wnt/β-catenin canonical pathway blocks testicular differentiation by repressing the expression of the Sertoli cell-specific gene Sox9 by an unknown mechanism. Using cell and embryonic gonad culture models, we show that activation of the Wnt/β-catenin pathway inhibits the expression of Sox9 and Amh, whereas mRNA and protein levels of Sry and steroidogenic factor 1 (Sf1), two key transcriptional regulators of Sox9, are not altered. Ectopic activation of Wnt/β-catenin signaling in male gonads led to a loss of Sf1 binding to the Tesco enhancer and absent Sox9 expression that we also observed in wild-type ovaries. Moreover, ectopic Wnt/β-catenin signaling induced the expression of the female somatic cell markers, Bmp2 and Rspo1, as a likely consequence of Sox9 loss. Wnt/β-catenin signaling in XY gonads did not, however, affect gene expression of the steroidogenic Leydig cell Sf1 target gene, Cyp11a1, or Sf1 binding to the Cyp11a1 promoter. Our data support a model in ovary development whereby activation of β-catenin prevents Sf1 binding to the Sox9 enhancer, thereby inhibiting Sox9 expression and Sertoli cell differentiation.

  13. Hexachlorophene inhibits Wnt/beta-catenin pathway by promoting Siah-mediated beta-catenin degradation.

    Science.gov (United States)

    Park, Seoyoung; Gwak, Jungsug; Cho, Munju; Song, Taeyun; Won, Jaejoon; Kim, Dong-Eun; Shin, Jae-Gook; Oh, Sangtaek

    2006-09-01

    Aberrant activation of Wnt/beta-catenin signaling and subsequent up-regulation of beta-catenin response transcription (CRT) is a critical event in the development of human colon cancer. Thus, Wnt/beta-catenin signaling is an attractive target for the development of anticancer therapeutics. In this study, we identified hexachlorophene as an inhibitor of Wnt/beta-catenin signaling from cell-based small-molecule screening. Hexachlorophene antagonized CRT that was stimulated by Wnt3a-conditioned medium by promoting the degradation of beta-catenin. This degradation pathway is Siah-1 and adenomatous polyposis colidependent, but glycogen synthase kinase-3beta and F-box beta-transducin repeat-containing protein-independent. In addition, hexachlorophene represses the expression of cyclin D1, which is a known beta-catenin target gene, and inhibits the growth of colon cancer cells. Our findings suggest that hexachlorophene attenuates Wnt/beta-catenin signaling through the Siah-1-mediated beta-catenin degradation.

  14. 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. © 2015. Published by The Company of Biologists Ltd.

  15. Temporal Regulation of Natural Killer T Cell Interferon Gamma Responses by β-Catenin-Dependent and -Independent Wnt Signaling.

    Science.gov (United States)

    Kling, Jessica C; Jordan, Margaret A; Pitt, Lauren A; Meiners, Jana; Thanh-Tran, Thao; Tran, Le Son; Nguyen, Tam T K; Mittal, Deepak; Villani, Rehan; Steptoe, Raymond J; Khosrotehrani, Kiarash; Berzins, Stuart P; Baxter, Alan G; Godfrey, Dale I; Blumenthal, Antje

    2018-01-01

    Natural killer T (NKT) cells are prominent innate-like lymphocytes in the liver with critical roles in immune responses during infection, cancer, and autoimmunity. Interferon gamma (IFN-γ) and IL-4 are key cytokines rapidly produced by NKT cells upon recognition of glycolipid antigens presented by antigen-presenting cells (APCs). It has previously been reported that the transcriptional coactivator β-catenin regulates NKT cell differentiation and functionally biases NKT cell responses toward IL-4, at the expense of IFN-γ production. β-Catenin is not only a central effector of Wnt signaling but also contributes to other signaling networks. It is currently unknown whether Wnt ligands regulate NKT cell functions. We thus investigated how Wnt ligands and β-catenin activity shape liver NKT cell functions in vivo in response to the glycolipid antigen, α-galactosylceramide (α-GalCer) using a mouse model. Pharmacologic targeting of β-catenin activity with ICG001, as well as myeloid-specific genetic ablation of Wntless (Wls) , to specifically target Wnt protein release by APCs, enhanced early IFN-γ responses. By contrast, within several hours of α-GalCer challenge, myeloid-specific Wls deficiency, as well as pharmacologic targeting of Wnt release using the small molecule inhibitor IWP-2 impaired α-GalCer-induced IFN-γ responses, independent of β-catenin activity. These data suggest that myeloid cell-derived Wnt ligands drive early Wnt/β-catenin signaling that curbs IFN-γ responses, but that, subsequently, Wnt ligands sustain IFN-γ expression independent of β-catenin activity. Our analyses in ICG001-treated mice confirmed a role for β-catenin activity in driving early IL-4 responses by liver NKT cells. However, neither pharmacologic nor genetic perturbation of Wnt production affected the IL-4 response, suggesting that IL-4 production by NKT cells in response to α-GalCer is not driven by released Wnt ligands. Collectively, these data reveal complex temporal

  16. Temporal Regulation of Natural Killer T Cell Interferon Gamma Responses by β-Catenin-Dependent and -Independent Wnt Signaling

    Directory of Open Access Journals (Sweden)

    Jessica C. Kling

    2018-03-01

    Full Text Available Natural killer T (NKT cells are prominent innate-like lymphocytes in the liver with critical roles in immune responses during infection, cancer, and autoimmunity. Interferon gamma (IFN-γ and IL-4 are key cytokines rapidly produced by NKT cells upon recognition of glycolipid antigens presented by antigen-presenting cells (APCs. It has previously been reported that the transcriptional coactivator β-catenin regulates NKT cell differentiation and functionally biases NKT cell responses toward IL-4, at the expense of IFN-γ production. β-Catenin is not only a central effector of Wnt signaling but also contributes to other signaling networks. It is currently unknown whether Wnt ligands regulate NKT cell functions. We thus investigated how Wnt ligands and β-catenin activity shape liver NKT cell functions in vivo in response to the glycolipid antigen, α-galactosylceramide (α-GalCer using a mouse model. Pharmacologic targeting of β-catenin activity with ICG001, as well as myeloid-specific genetic ablation of Wntless (Wls, to specifically target Wnt protein release by APCs, enhanced early IFN-γ responses. By contrast, within several hours of α-GalCer challenge, myeloid-specific Wls deficiency, as well as pharmacologic targeting of Wnt release using the small molecule inhibitor IWP-2 impaired α-GalCer-induced IFN-γ responses, independent of β-catenin activity. These data suggest that myeloid cell-derived Wnt ligands drive early Wnt/β-catenin signaling that curbs IFN-γ responses, but that, subsequently, Wnt ligands sustain IFN-γ expression independent of β-catenin activity. Our analyses in ICG001-treated mice confirmed a role for β-catenin activity in driving early IL-4 responses by liver NKT cells. However, neither pharmacologic nor genetic perturbation of Wnt production affected the IL-4 response, suggesting that IL-4 production by NKT cells in response to α-GalCer is not driven by released Wnt ligands. Collectively, these data reveal

  17. Genetic Screening of WNT4 and WNT5B in Two Populations with Deviating Bone Mineral Densities

    DEFF Research Database (Denmark)

    Hendrickx, Gretl; Boudin, Eveline; Steenackers, Ellen

    2017-01-01

    A role for WNT4 and WNT5B in bone metabolism was indicated by genome-wide association studies (GWAS) and a Wnt4 knockout mouse model. The aim of this study was therefore to replicate and further investigate the causality between genetic variation in WNT4 and WNT5B and deviating bone mineral density...... (BMD) values. A WNT4 and WNT5B mutation screening was performed in patients with craniotubular hyperostosis using Sanger sequencing. Here, no putative causal mutations were detected. Moreover, a high and low BMD cohort was selected from the Odense Androgen Study population for re-sequencing. In WNT4 we...... detected four variants (three rare, one common), while in WNT5B we detected five variants (two rare, three common). For the common variants, no significant difference in genotype frequencies between the high and low BMD cohorts was observed. The SNPs associated with the GWAS were genotyped in these cohorts...

  18. The way Wnt works: Components and mechanism

    Science.gov (United States)

    SAITO-DIAZ, KENYI; CHEN, TONY W.; WANG, XIAOXI; THORNE, CURTIS A.; WALLACE, HEATHER A.; PAGE-MCCAW, ANDREA; LEE, ETHAN

    2013-01-01

    The canonical Wnt/β-catenin pathway is an ancient and evolutionarily conserved signaling pathway that is required for the proper development of all metazoans, from the basal demosponge Amphimedon queenslandica to humans. Misregulation of Wnt signaling is implicated in many human diseases, making this pathway an intense area of research in industry as well as academia. In this review, we explore our current understanding of the molecular steps involved in the transduction of a Wnt signal. We will focus on how the critical Wnt pathway component, β-catenin, is in a “futile cycle” of constant synthesis and degradation and how this cycle is disrupted upon pathway activation. We describe the role of the Wnt pathway in major human cancers and in the control of stem cell self-renewal in the developing organism and in adults. Finally, we describe well-accepted criteria that have been proposed as evidence for the involvement of a molecule in regulating the canonical Wnt pathway. PMID:23256519

  19. Evidence for involvement of Wnt signalling in body polarities, cell proliferation, and the neuro-sensory system in an adult ctenophore.

    Science.gov (United States)

    Jager, Muriel; Dayraud, Cyrielle; Mialot, Antoine; Quéinnec, Eric; le Guyader, Hervé; Manuel, Michaël

    2013-01-01

    Signalling through the Wnt family of secreted proteins originated in a common metazoan ancestor and greatly influenced the evolution of animal body plans. In bilaterians, Wnt signalling plays multiple fundamental roles during embryonic development and in adult tissues, notably in axial patterning, neural development and stem cell regulation. Studies in various cnidarian species have particularly highlighted the evolutionarily conserved role of the Wnt/β-catenin pathway in specification and patterning of the primary embryonic axis. However in another key non-bilaterian phylum, Ctenophora, Wnts are not involved in early establishment of the body axis during embryogenesis. We analysed the expression in the adult of the ctenophore Pleurobrachia pileus of 11 orthologues of Wnt signalling genes including all ctenophore Wnt ligands and Fz receptors and several members of the intracellular β-catenin pathway machinery. All genes are strongly expressed around the mouth margin at the oral pole, evoking the Wnt oral centre of cnidarians. This observation is consistent with primary axis polarisation by the Wnts being a universal metazoan feature, secondarily lost in ctenophores during early development but retained in the adult. In addition, local expression of Wnt signalling genes was seen in various anatomical structures of the body including in the locomotory comb rows, where their complex deployment suggests control by the Wnts of local comb polarity. Other important contexts of Wnt involvement which probably evolved before the ctenophore/cnidarian/bilaterian split include proliferating stem cells and progenitors irrespective of cell types, and developing as well as differentiated neuro-sensory structures.

  20. Wnt signaling, a novel pathway regulating blood pressure? State of the art review.

    Science.gov (United States)

    Abou Ziki, Maen D; Mani, Arya

    2017-07-01

    Recent antihypertensive trials show conflicting results on blood pressure (BP) targets in patient populations with different metabolic profiles, with lowest benefit from tight BP control observed in patients with type 2 diabetes mellitus. This paradox could arise from the heterogeneity of study populations and underscores the importance of precision medicine initiatives towards understanding and treating hypertension. Wnt signaling pathways and genetic variations in its signaling peptides have been recently associated with metabolic syndrome, hypertension and diabetes, generating a breakthrough for advancement of precision medicine in the field of hypertension. We performed a review of PubMed for publications addressing the contributions of Wnt to BP regulation and hypertension. In addition, we performed a manual search of the reference lists for relevant articles, and included unpublished observations from our laboratory. There is emerging evidence for Wnt's role in BP regulation and its involvement in the pathogenesis of hypertension. Wnt signaling has pleiotropic effects on distinct pathways that involve vascular smooth muscle plasticity, and cardiac, renal, and neural physiology. Hypertension is a heterogeneous disease with unique molecular pathways regulating its response to therapy. Recognition of these pathways is a prerequisite to identify novel targets for drug development and personalizing medicine. A review of Wnt signaling reveals its emerging role in BP regulation and as a target for novel drug development that has the potential to transform the therapy of hypertension in specific populations. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Toosendanin inhibits adipogenesis by activating Wnt/β-catenin signaling.

    Science.gov (United States)

    Chen, Tian-Xing; Cheng, Xiao-Ying; Wang, Yun; Yin, Wu

    2018-03-15

    Toosendanin (TSN), a triterpenoid extracted from Melia toosendan, has been reported to possess anti-oxidant, anti-inflammatory, anti-allergic, and anti-arthritic activities. However, its anti-adipogenic effect remains unknown. Here, we found that TSN dose-dependently attenuated lipid accumulation in preadipocytes 3T3-L1 as evidenced by Oil Red O staining. TSN also significantly downregulated mRNA and protein levels of adipocytokines (adiponectin and leptin), CCAAT/enhancer binding proteins α (C/EBP-α), peroxisome proliferator-activated receptor γ (PPAR-γ), fatty acid synthase, and acetyl-CoA carboxylase in adipocytes. To understand the mechanism, we observed that TSN effectively activated Wnt/β-catenin pathway, in which TSN increased low density lipoprotein receptor related protein 6, disheveled 2, β-catenin, and cyclin D1 expression levels, while it inactivated glycogen synthase kinase 3β by enhancing its phosphorylation. Moreover, TSN reduced weight of gonadal white fat and serum triacylglycerol (TAG) content in high-fat diet (HFD)-fed mice. Interestingly, the in vivo studies also demonstrated that TSN promoted the expression of β-catenin, but accordingly repressed C/EBP-α and PPAR-γ expression in HFD-induced mice. Overall, TSN is capable of inhibiting the lipogenesis of adipocytes by activating the Wnt/β-catenin pathway, suggesting potential application of TSN as a natural anti-obesity agent.

  2. Fluoxetine ameliorates cartilage degradation in osteoarthritis by inhibiting Wnt/β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Kentaro Miyamoto

    Full Text Available Abnormal activation of the Wnt/β-catenin signaling is implicated in the osteoarthritis (OA pathology. We searched for a pre-approved drug that suppresses abnormally activated Wnt/β-catenin signaling and has a potency to reduce joint pathology in OA. We introduced the TOPFlash reporter plasmid into HCS-2/8 human chondrosarcoma cells to estimate the Wnt/β-catenin activity in the presence of 10 μM each compound in a panel of pre-approved drugs. We found that fluoxetine, an antidepressant in the class of selective serotonin reuptake inhibitors (SSRI, down-regulated Wnt/β-catenin signaling in human chondrosarcoma cells. Fluoxetine inhibited both Wnt3A- and LiCl-induced loss of proteoglycans in chondrogenically differentiated ATDC5 cells. Fluoxetine increased expression of Sox9 (the chondrogenic master regulator, and decreased expressions of Axin2 (a marker for Wnt/β-catenin signaling and Mmp13 (matrix metalloproteinase 13. Fluoxetine suppressed a LiCl-induced increase of total β-catenin and a LiCl-induced decrease of phosphorylated β-catenin in a dose-dependent manner. An in vitro protein-binding assay showed that fluoxetine enhanced binding of β-catenin with Axin1, which is a scaffold protein forming the degradation complex for β-catenin. Fluoxetine suppressed LiCl-induced β-catenin accumulation in human OA chondrocytes. Intraarticular injection of fluoxetine in a rat OA model ameliorated OA progression and suppressed β-catenin accumulation.

  3. Aluminum trichloride impairs bone and downregulates Wnt/β-catenin signaling pathway in young growing rats.

    Science.gov (United States)

    Sun, Xudong; Cao, Zheng; Zhang, Qiuyue; Liu, Shimin; Xu, Feibo; Che, Jianfang; Zhu, Yanzhu; Li, Yanfei; Pan, Chuanyi; Liang, Wannan

    2015-12-01

    Aluminum (Al) can accumulate in bone and cause bone diseases. Few studies have investigated molecular mechanism of Al-induced bone diseases. Thus, in this study, rats were orally exposed to 0 (control group) and 0.4 g/L aluminum trichloride (AlCl3) (treatment group) for 30, 60, 90 or 120 days, respectively. The Al content of femora and serum, bone histological structure, bone mineral density (BMD) of the distal and proximal femoral metaphysis and Wnt/β-catenin signaling pathway (the mRNA expressions of Wnt3a, Fzd2, LRP-5, β-catenin, Tcf4, cyclin D1 and c-Myc, the protein levels of Wnt3a and β-catenin, the activities of Fzd2 and LRP-5) in rat femora were determined on day 30, 60, 90 or 120, respectively. The results showed that the Al contents of femora and serum were increased, the BMD of the distal and proximal femoral metaphysis were decreased, the femora histological structure were disrupted, the mRNA expressions of Wnt3a, Fzd2, LRP-5, β-catenin, Tcf4, cyclin D1 and c-Myc, the protein levels of Wnt3a and β-catenin, the activities of Fzd2 and LRP-5 were all decreased in the treatment group compared with the control group with time prolonged. These results indicated that AlCl3 impaired femora by inhibiting the Wnt/β-catenin signaling pathway in young growing rats. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Engineering Synthetic Proteins to Generate Ca2+Signals in Mammalian Cells.

    Science.gov (United States)

    Qudrat, Anam; Truong, Kevin

    2017-03-17

    The versatility of Ca 2+ signals allows it to regulate diverse cellular processes such as migration, apoptosis, motility and exocytosis. In some receptors (e.g., VEGFR2), Ca 2+ signals are generated upon binding their ligand(s) (e.g., VEGF-A). Here, we employed a design strategy to engineer proteins that generate a Ca 2+ signal upon binding various extracellular stimuli by creating fusions of protein domains that oligomerize to the transmembrane domain and the cytoplasmic tail of the VEGFR2. To test the strategy, we created chimeric proteins that generate Ca 2+ signals upon stimulation with various extracellular stimuli (e.g., rapamycin, EDTA or extracellular free Ca 2+ ). By coupling these chimeric proteins that generate Ca 2+ signals with proteins that respond to Ca 2+ signals, we rewired, for example, dynamic cellular blebbing to increases in extracellular free Ca 2+ . Thus, using this design strategy, it is possible to engineer proteins to generate a Ca 2+ signal to rewire a wide range of extracellular stimuli to a wide range of Ca 2+ -activated processes.

  5. The Wnt signaling pathway is differentially expressed during the bovine herpesvirus 1 latency-reactivation cycle: evidence that two protein kinases associated with neuronal survival (Akt3 and bone morphogenetic protein....

    Science.gov (United States)

    Sensory neurons in trigeminal ganglia (TG) of calves latently infected with bovine herpesvirus 1 (BoHV-1) abundantly express latency-related (LR) gene products, including a protein (ORF2) and two micro-RNAs. Recent studies in mouse neuroblastoma cells (Neuro-2A) demonstrated ORF2 interacts with ß-ca...

  6. Wnt some lose some: transcriptional governance of stem cells by Wnt/β-catenin signaling

    Science.gov (United States)

    Lien, Wen-Hui; Fuchs, Elaine

    2014-01-01

    In mammals, Wnt/β-catenin signaling features prominently in stem cells and cancers, but how and for what purposes have been matters of much debate. In this review, we summarize our current knowledge of Wnt/β-catenin signaling and its downstream transcriptional regulators in normal and malignant stem cells. We centered this review largely on three types of stem cells—embryonic stem cells, hair follicle stem cells, and intestinal epithelial stem cells—in which the roles of Wnt/β-catenin have been extensively studied. Using these models, we unravel how many controversial issues surrounding Wnt signaling have been resolved by dissecting the diversity of its downstream circuitry and effectors, often leading to opposite outcomes of Wnt/β-catenin-mediated regulation and differences rooted in stage- and context-dependent effects. PMID:25030692

  7. Protein engineering for metabolic engineering: current and next-generation tools

    Science.gov (United States)

    Marcheschi, Ryan J.; Gronenberg, Luisa S.; Liao, James C.

    2014-01-01

    Protein engineering in the context of metabolic engineering is increasingly important to the field of industrial biotechnology. As the demand for biologically-produced food, fuels, chemicals, food additives, and pharmaceuticals continues to grow, the ability to design and modify proteins to accomplish new functions will be required to meet the high productivity demands for the metabolism of engineered organisms. This article reviews advances of selecting, modeling, and engineering proteins to improve or alter their activity. Some of the methods have only recently been developed for general use and are just beginning to find greater application in the metabolic engineering community. We also discuss methods of generating random and targeted diversity in proteins to generate mutant libraries for analysis. Recent uses of these techniques to alter cofactor use, produce non-natural amino acids, alcohols, and carboxylic acids, and alter organism phenotypes are presented and discussed as examples of the successful engineering of proteins for metabolic engineering purposes. PMID:23589443

  8. Bioactive Properties of Maillard Reaction Products Generated From Food Protein-derived Peptides.

    Science.gov (United States)

    Arihara, K; Zhou, L; Ohata, M

    Food protein-derived peptides are promising food ingredients for developing functional foods, since various bioactive peptides are released from food proteins. The Maillard reaction, which plays an important role in most processed foods, generates various chemical components during processing. Although changes of amino acids or proteins and reduced sugars by the Maillard reaction have been studied extensively, such changes of peptides by the Maillard reaction are still not resolved enough. Since food protein-derived peptides are widely utilized in many processed foods, it deserves concern and research on the changes of peptides by the Maillard reaction in foods during processing or storage. This chapter initially overviewed food protein-derived bioactive peptides. Then, Maillard reaction products generated from peptides are discussed. We focused particularly on their bioactivities. © 2017 Elsevier Inc. All rights reserved.

  9. Exogenous DKK-3/REIC inhibits Wnt/β-catenin signaling and cell proliferation in human kidney cancer KPK1.

    Science.gov (United States)

    Xu, Jiaqi; Sadahira, Takuya; Kinoshita, Rie; Li, Shun-Ai; Huang, Peng; Wada, Koichiro; Araki, Motoo; Ochiai, Kazuhiko; Noguchi, Hirofumi; Sakaguchi, Masakiyo; Nasu, Yasutomo; Watanabe, Masami

    2017-11-01

    The third member of the Dickkopf family (DKK-3), also known as reduced expression in immortalized cells (REIC), is a tumor suppressor present in a variety of tumor cells. Regarding the regulation of the Wnt/β-catenin signaling pathway, exogenous DKK-1 and DKK-2 are reported to inhibit Wnt signaling by binding the associated effectors. However, whether exogenous DKK-3 inhibits Wnt signaling remains unclear. A recombinant protein of human full-length DKK-3 was used to investigate the exogenous effects of the protein in vitro in KPK1 human renal cell carcinoma cells. It was demonstrated that the expression of phosphorylated (p-)β-catenin (inactive form as the transcriptional factor) was increased in KPK1 cells treated with the exogenous DKK-3 protein. The levels of non-p-β-catenin (activated form of β-catenin) were consistently decreased. It was revealed that the expression of transcription factor (TCF) 1 and c-Myc, the downstream transcription factors of the Wnt/β-catenin signaling pathway, was inhibited following treatment with DKK-3. A cancer cell viability assay confirmed the anti-proliferative effects of exogenous DKK-3 protein, which was consistent with a suppressed Wnt/β-catenin signaling cascade. In addition, as low-density lipoprotein receptor-related protein 6 (LRP6) is a receptor of DKK-1 and DKK-2 and their interaction on the cell surface inhibits Wnt/β-catenin signaling, it was examined whether the exogenous DKK-3 protein affects LRP6-mediated Wnt/β-catenin signaling. The LRP6 gene was silenced and the effects of DKK-3 on the time course of the upregulation of p-β-catenin expression were subsequently analyzed. Notably, LRP6 depletion elevated the base level of p-β-catenin; however, there was no significant effect on its upregulation course or expression pattern. These findings indicate that exogenous DKK-3 upregulates p-β-catenin and inhibits Wnt/β-catenin signaling in an LRP6-independent manner. Therefore, exogenous DKK-3 protein may inhibit

  10. HuR represses Wnt/β-catenin-mediated transcriptional activity by promoting cytoplasmic localization of β-catenin

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Inae; Hur, Jung; Jeong, Sunjoo, E-mail: sjsj@dankook.ac.kr

    2015-01-30

    Highlights: • Wnt signaling as well as β-catenin overexpression enhance HuR cytoplasmic export. • HuR overexpression promotes cytoplasmic localization of β-catenin from the perinuclear fraction. • Wnt/β-catenin-mediated transcriptional activity is repressesed by HuR. - Abstract: β-Catenin is the key transcriptional activator of canonical Wnt signaling in the nucleus; thus, nuclear accumulation of β-catenin is a critical step for expressing target genes. β-Catenin accumulates in the nucleus of cancer cells where it activates oncogenic target genes. Hu antigen R (HuR) is a RNA binding protein that regulates multiple post-transcriptional processes including RNA stability. Thus, cytoplasmic HuR protein may be involved in tumorigenesis by stabilizing oncogenic transcripts, but the molecular mechanism remains unclear. Here, we observed that Wnt/β-catenin signaling induced export of the HuR protein, whereas HuR overexpression promoted accumulation of the β-catenin protein in the cytoplasm. Thus, Wnt/β-catenin-mediated transcriptional activity in the nucleus was reduced by overexpressing HuR. These results suggest novel and uncharacterized cytoplasmic β-catenin functions related to HuR-mediated RNA metabolism in cancer cells.

  11. HuR represses Wnt/β-catenin-mediated transcriptional activity by promoting cytoplasmic localization of β-catenin

    International Nuclear Information System (INIS)

    Kim, Inae; Hur, Jung; Jeong, Sunjoo

    2015-01-01

    Highlights: • Wnt signaling as well as β-catenin overexpression enhance HuR cytoplasmic export. • HuR overexpression promotes cytoplasmic localization of β-catenin from the perinuclear fraction. • Wnt/β-catenin-mediated transcriptional activity is repressesed by HuR. - Abstract: β-Catenin is the key transcriptional activator of canonical Wnt signaling in the nucleus; thus, nuclear accumulation of β-catenin is a critical step for expressing target genes. β-Catenin accumulates in the nucleus of cancer cells where it activates oncogenic target genes. Hu antigen R (HuR) is a RNA binding protein that regulates multiple post-transcriptional processes including RNA stability. Thus, cytoplasmic HuR protein may be involved in tumorigenesis by stabilizing oncogenic transcripts, but the molecular mechanism remains unclear. Here, we observed that Wnt/β-catenin signaling induced export of the HuR protein, whereas HuR overexpression promoted accumulation of the β-catenin protein in the cytoplasm. Thus, Wnt/β-catenin-mediated transcriptional activity in the nucleus was reduced by overexpressing HuR. These results suggest novel and uncharacterized cytoplasmic β-catenin functions related to HuR-mediated RNA metabolism in cancer cells

  12. Cooperative working of bacterial chromosome replication proteins generated by a reconstituted protein expression system

    Science.gov (United States)

    Fujiwara, Kei; Katayama, Tsutomu; Nomura, Shin-ichiro M.

    2013-01-01

    Replication of all living cells relies on the multirounds flow of the central dogma. Especially, expression of DNA replication proteins is a key step to circulate the processes of the central dogma. Here we achieved the entire sequential transcription–translation–replication process by autonomous expression of chromosomal DNA replication machineries from a reconstituted transcription–translation system (PURE system). We found that low temperature is essential to express a complex protein, DNA polymerase III, in a single tube using the PURE system. Addition of the 13 genes, encoding initiator, DNA helicase, helicase loader, RNA primase and DNA polymerase III to the PURE system gave rise to a DNA replication system by a coupling manner. An artificial genetic circuit demonstrated that the DNA produced as a result of the replication is able to provide genetic information for proteins, indicating the in vitro central dogma can sequentially undergo two rounds. PMID:23737447

  13. Hypoxia-inducible factor-2α-dependent hypoxic induction of Wnt10b expression in adipogenic cells.

    Science.gov (United States)

    Park, Young-Kwon; Park, Bongju; Lee, Seongyeol; Choi, Kang; Moon, Yunwon; Park, Hyunsung

    2013-09-06

    Adipocyte hyperplasia and hypertrophy in obesity can lead to many changes in adipose tissue, such as hypoxia, metabolic dysregulation, and enhanced secretion of cytokines. In this study, hypoxia increased the expression of Wnt10b in both human and mouse adipogenic cells, but not in hypoxia-inducible factor (HIF)-2α-deficient adipogenic cells. Chromatin immunoprecipitation analysis revealed that HIF-2α, but not HIF-1α, bound to the Wnt10b enhancer region as well as upstream of the Wnt1 gene, which is encoded by an antisense strand of the Wnt10b gene. Hypoxia-conditioned medium (H-CM) induced phosphorylation of lipoprotein-receptor-related protein 6 as well as β-catenin-dependent gene expression in normoxic cells, which suggests that H-CM contains canonical Wnt signals. Furthermore, adipogenesis of both human mesenchymal stem cells and mouse preadipocytes was inhibited by H-CM even under normoxic conditions. These results suggest that O2 concentration gradients influence the formation of Wnt ligand gradients, which are involved in the regulation of pluripotency, cell proliferation, and cell differentiation.

  14. The evolving roles of canonical WNT signaling in stem cells and tumorigenesis: Implications in targeted cancer therapies

    Science.gov (United States)

    Yang, Ke; Wang, Xin; Zhang, Hongmei; Wang, Zhongliang; Nan, Guoxin; Li, Yasha; Zhang, Fugui; Mohammed, Maryam K.; Haydon, Rex C.; Luu, Hue H.; Bi, Yang; He, Tong-Chuan

    2015-01-01

    The canonical WNT/β-catenin signaling pathway governs a myriad of biological processes underlying development and maintenance of adult tissue homeostasis, including regulation of stem cell self-renewal, cell proliferation, differentiation, and apoptosis. WNTs are secreted lipid-modified glycoproteins that act as short-range ligands to activate receptor-mediated signaling pathways. The hallmark of the canonical pathway is the activation of β-catenin mediated transcriptional activity. Canonical WNTs control the β-catenin dynamics as the cytoplasmic level of β-catenin is tightly regulated via phosphorylation by the ‘destruction complex’, consisting of glycogen synthase kinase 3β (GSK3β), casein kinase 1α (CK1α), the scaffold protein AXIN, and the tumor suppressor adenomatous polyposis coli (APC). Aberrant regulation of this signaling cascade is associated with varieties of human diseases, especially cancers. Over the past decade, significant progress has been made in understanding the mechanisms of canonical WNT signaling. In this review, we focus on the current understanding of WNT signaling at the extracellular, cytoplasmic membrane, and intracellular/nuclear levels, including the emerging knowledge of crosstalk with other pathways. Recent progresses in developing novel WNT pathway-targeted therapies will also be reviewed. Thus, this review is intended to serve as a refresher of the current understanding about the physiologic and pathogenic roles of WNT/β-catenin signaling pathway, and to outline potential therapeutic opportunities by targeting the canonical WNT pathway. PMID:26618721

  15. Aluminum trichloride inhibits osteoblastic differentiation through inactivation of Wnt/β-catenin signaling pathway in rat osteoblasts.

    Science.gov (United States)

    Cao, Zheng; Fu, Yang; Sun, Xudong; Zhang, Qiuyue; Xu, Feibo; Li, Yanfei

    2016-03-01

    Exposure to aluminum (Al) suppresses bone formation. Osteoblastic differentiation plays a key role in the process of bone formation. However, the effect of Al on osteoblastic differentiation is still controversial, and the mechanism remains unclear. To investigate the effect of Al on osteoblastic differentiation and whether Wnt signaling pathway was involved in it, the primary rat osteoblasts were exposed to 1/40 IC50, 1/20 IC50 and 1/10 IC50 of aluminum trichloride (AlCl3) for 24h, respectively. The activity analysis of alkaline phosphate, qRT-PCR analysis of type I collagen, alkaline phosphate, Wnt3a and Dkk-1, Western blot analysis of p-GSK3β, GSK3β and β-catenin protein and Immunofluorescence staining for β-catenin suggested that AlCl3 inhibited osteoblastic differentiation and Wnt/β-catenin pathway. Moreover, we found exogenous Wnt3a application reversed the inhibitory effect of AlCl3 on osteoblastic differentiation, accompanied by activating the Wnt/β-catenin pathway. Taken together, these findings suggest that AlCl3 inhibites osteoblastic differentiation through inactivation of Wnt/β-catenin pathway in osteoblasts. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Inhibition of WNT signaling in the bone marrow niche prevents the development of MDS in the Apcdel/+ MDS mouse model.

    Science.gov (United States)

    Stoddart, Angela; Wang, Jianghong; Hu, Chunmei; Fernald, Anthony A; Davis, Elizabeth M; Cheng, Jason X; Le Beau, Michelle M

    2017-06-01

    There is accumulating evidence that functional alteration(s) of the bone marrow (BM) microenvironment contribute to the development of some myeloid disorders, such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). In addition to a cell-intrinsic role of WNT activation in leukemia stem cells, WNT activation in the BM niche is also thought to contribute to the pathogenesis of MDS and AML. We previously showed that the Apc -haploinsufficient mice ( Apc del/+ ) model MDS induced by an aberrant BM microenvironment. We sought to determine whether Apc, a multifunctional protein and key negative regulator of the canonical β-catenin (Ctnnb1)/WNT-signaling pathway, mediates this disease through modulating WNT signaling, and whether inhibition of WNT signaling prevents the development of MDS in Apc del/+ mice. Here, we demonstrate that loss of 1 copy of Ctnnb1 is sufficient to prevent the development of MDS in Apc del/+ mice and that altered canonical WNT signaling in the microenvironment is responsible for the disease. Furthermore, the US Food and Drug Administration (FDA)-approved drug pyrvinium delays and/or inhibits disease in Apc del /+ mice, even when it is administered after the presentation of anemia. Other groups have observed increased nuclear CTNNB1 in stromal cells from a high frequency of MDS/AML patients, a finding that together with our results highlights a potential new strategy for treating some myeloid disorders. © 2017 by The American Society of Hematology.

  17. Oxidation of myosin by haem proteins generates myosin radicals and protein cross-links

    DEFF Research Database (Denmark)

    Lametsch, Marianne Lund; Luxford, Catherine; Skibsted, Leif Horsfelt

    2008-01-01

    as a result of the reaction with activated haem proteins (horseradish peroxidase/H2O2) and met-myoglobin/H2O2) has been investigated by EPR spectroscopy and amino-acid consumption, product formation has been characterized by HPLC, and changes in protein integrity have been determined by SDS/PAGE. Multiple...... of thiyl and tyrosyl radicals is consistent with the observed consumption of cysteine and tyrosine residues, the detection of di-tyrosine by HPLC and the detection of both reducible (disulfide bond) and non-reducible cross-links between myosin molecules by SDS/PAGE. The time course of radical formation...

  18. Calorimetric and spectroscopic properties of small globular proteins (bovine serum albumin, hemoglobin) after free radical generation

    International Nuclear Information System (INIS)

    Farkas, N.; Belagyi, J.; Lorinczy, D.

    2003-01-01

    Mild oxidation of -SH-containing proteins (serum albumin, hemoglobin) by Ce(IV)-ions in the presence of the spin trap phenyl-tert-butylnitrone (PBN) resulted in the appearance of strongly immobilized nitroxide free radicals which evidences the formation of thiyl radicals on the thiol site of the proteins. In hydroxyl free radical generating system a fraction of strongly immobilized nitroxide radicals was also detected in these proteins, which implies that the oxidation of a fraction of the thiol groups was also involved in the free radical reaction. According to the differential scanning calorimetry (DSC) experiments the melting processes of the proteins were calorimetrically irreversible, therefore the two-state kinetic model was used to evaluate the experiments. The results support the view that site-specific interaction of SH-containing proteins with hydroxyl and thiyl free radicals is able to modify the internal dynamics of proteins and affect the conformation of large molecules

  19. CD8+ T cells mediate the regenerative PTH effect in hPDL cells via Wnt10b signaling.

    Science.gov (United States)

    Wolf, Michael; Lossdörfer, Stefan; Marciniak, Jana; Römer, Piero; Kirschneck, Christian; Craveiro, Rogerio; Deschner, James; Jäger, Andreas

    2016-11-01

    It was the aim of the present investigation to examine whether the stimulating effect of parathyroid hormone (PTH) on human periodontal ligament (hPDL) cell proliferation and differentiation would be enhanced by hPDL/T-cell interaction involving Wnt10b signaling as a mediating pathway. hPDL cells were cultured from healthy premolar tissues of three adolescent orthodontic patients and exposed to PTH(1-34) in monocultures or co-cultures with CD8 + T cells. At harvest, proliferation, alkaline phosphatase-specific activity (ALP), and osteocalcin production were determined by immunofluorescence cytochemistry, real-time PCR, biochemical assay, and ELISA. Wnt10b signaling was analyzed by the use of a specific WNT10b neutralizing antibody. PTH(1-34) stimulation of T cells significantly increased Wnt10b expression and production. Wnt10b exposure of hPDL cells enhanced proliferation and differentiation. PDL cells co-cultured with T cells showed a Wnt10b-dependent regulation of proliferation and differentiation parameters. The addition of a Wnt10b-neutralizing Ab to the co-culture medium resulted in a significant inhibition of the PTH(1-34) effect on proliferation, ALP-specific activity, and osteocalcin protein expression. Our findings provide novel insight into the mechanism of action of PTH on hPDL cells and establish the interplay of T cells and hPDL cells via the Wnt10b pathway as a modulating factor for the anabolic properties of the hormone in periodontal regeneration.

  20. Vasculogenesis and angiogenesis initiation under normoxic conditions through Wnt/β-catenin pathway in gliomas.

    Science.gov (United States)

    Vallée, Alexandre; Guillevin, Rémy; Vallée, Jean-Noël

    2018-01-26

    The canonical Wnt/β-catenin pathway is up-regulated in gliomas and involved in proliferation, invasion, apoptosis, vasculogenesis and angiogenesis. Nuclear β-catenin accumulation correlates with malignancy. Hypoxia activates hypoxia-inducible factor (HIF)-1α by inhibiting HIF-1α prolyl hydroxylation, which promotes glycolytic energy metabolism, vasculogenesis and angiogenesis, whereas HIF-1α is degraded by the HIF prolyl hydroxylase under normoxic conditions. We focus this review on the links between the activated Wnt/β-catenin pathway and the mechanisms underlying vasculogenesis and angiogenesis through HIF-1α under normoxic conditions in gliomas. Wnt-induced epidermal growth factor receptor/phosphatidylinositol 3-kinase (PI3K)/Akt signaling, Wnt-induced signal transducers and activators of transcription 3 (STAT3) signaling, and Wnt/β-catenin target gene transduction (c-Myc) can activate HIF-1α in a hypoxia-independent manner. The PI3K/Akt/mammalian target of rapamycin pathway activates HIF-1α through eukaryotic translation initiation factor 4E-binding protein 1 and STAT3. The β-catenin/T-cell factor 4 complex directly binds to STAT3 and activates HIF-1α, which up-regulates the Wnt/β-catenin target genes cyclin D1 and c-Myc in a positive feedback loop. Phosphorylated STAT3 by interleukin-6 or leukemia inhibitory factor activates HIF-1α even under normoxic conditions. The activation of the Wnt/β-catenin pathway induces, via the Wnt target genes c-Myc and cyclin D1 or via HIF-1α, gene transactivation encoding aerobic glycolysis enzymes, such as glucose transporter, hexokinase 2, pyruvate kinase M2, pyruvate dehydrogenase kinase 1 and lactate dehydrogenase-A, leading to lactate production, as the primary alternative of ATP, at all oxygen levels, even in normoxic conditions. Lactate released by glioma cells via the monocarboxylate lactate transporter-1 up-regulated by HIF-1α and lactate anion activates HIF-1α in normoxic endothelial cells by

  1. Leukemia-associated gene MLAA-34 reduces arsenic trioxide-induced apoptosis in HeLa cells via activation of the Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Zhang, Pengyu; Zhao, Xuan; Zhang, Wenjuan; He, Aili; Lei, Bo; Zhang, Wanggang; Chen, Yinxia

    2017-01-01

    Our laboratory previously used the SEREX method in U937 cells and identified a novel leukemia-associated gene MLAA-34, a novel splice variant of CAB39L associated with acute monocytic leukemia, that exhibited anti-apoptotic activities in U937 cells. Whether MLAA-34 has an anti-apoptotic role in other tumor cells has not yet been reported. We explored whether MLAA-34 exhibited anti-apoptotic effects in HeLa cervical cancer cells and the possible mechanism of action. We generated a HeLa cell line stably expressing MLAA-34 and found that MLAA-34 overexpression had no effect on the growth, apoptosis and cell cycle of HeLa cells. However, upon treatment with arsenic trioxide (ATO) to induce apoptosis, the cell viability and colony formation ability of ATO-treated MLAA-34 stable HeLa cells were significantly higher than that of ATO-treated controls, and the apoptosis rate and proportion of G2/M cells also decreased. We found that ATO treatment of HeLa cells resulted in significant decreases in the expression of β-catenin mRNA and protein and the downstream target factors c-Myc, cyclin B1, and cyclin D1 in the Wnt signaling pathway. Notably, ATO-treated MLAA-34 stable HeLa cells showed a significant reduction in the ATO-mediated downregulation of these factors. In addition, MLAA-34 overexpression significantly increased the expression of nuclear β-catenin protein in ATO-treated cells compared with HeLa cells treated only with ATO. Thus, here we have found that the Wnt/β-catenin signaling pathway is involved in ATO-induced apoptosis in HeLa cells. MLAA-34 reduces ATO-induced apoptosis and G2/M arrest, and the anti-apoptotic effect may be achieved by activating the Wnt/β-catenin signaling pathway in HeLa cells.

  2. Dact2 represses PITX2 transcriptional activation and cell proliferation through Wnt/beta-catenin signaling during odontogenesis.

    Science.gov (United States)

    Li, Xiao; Florez, Sergio; Wang, Jianbo; Cao, Huojun; Amendt, Brad A

    2013-01-01

    Dact proteins belong to the Dapper/Frodo protein family and function as cytoplasmic attenuators in Wnt and TGFβ signaling. Previous studies show that Dact1 is a potent Wnt signaling inhibitor by promoting degradation of β-catenin. We report a new mechanism for Dact2 function as an inhibitor of the canonical Wnt signaling pathway by interacting with PITX2. PITX2 is a downstream transcription factor in Wnt/β-catenin signaling, and PITX2 synergizes with Lef-1 to activate downstream genes. Immunohistochemistry verified the expression of Dact2 in the tooth epithelium, which correlated with Pitx2 epithelial expression. Dact2 loss of function and PITX2 gain of function studies reveal a feedback mechanism for controlling Dact2 expression. Pitx2 endogenously activates Dact2 expression and Dact2 feeds back to repress Pitx2 transcriptional activity. A Topflash reporter system was employed showing PITX2 activation of Wnt signaling, which is attenuated by Dact2. Transient transfections demonstrate the inhibitory effect of Dact2 on critical dental epithelial differentiation factors during tooth development. Dact2 significantly inhibits PITX2 activation of the Dlx2 and amelogenin promoters. Multiple lines of evidence conclude the inhibition is achieved by the physical interaction between Dact2 and Pitx2 proteins. The loss of function of Dact2 also reveals increased cell proliferation due to up-regulated Wnt downstream genes, cyclinD1 and cyclinD2. In summary, we have identified a novel role for Dact2 as an inhibitor of the canonical Wnt pathway in embryonic tooth development through its regulation of cell proliferation and differentiation.

  3. Dact2 represses PITX2 transcriptional activation and cell proliferation through Wnt/beta-catenin signaling during odontogenesis.

    Directory of Open Access Journals (Sweden)

    Xiao Li

    Full Text Available Dact proteins belong to the Dapper/Frodo protein family and function as cytoplasmic attenuators in Wnt and TGFβ signaling. Previous studies show that Dact1 is a potent Wnt signaling inhibitor by promoting degradation of β-catenin. We report a new mechanism for Dact2 function as an inhibitor of the canonical Wnt signaling pathway by interacting with PITX2. PITX2 is a downstream transcription factor in Wnt/β-catenin signaling, and PITX2 synergizes with Lef-1 to activate downstream genes. Immunohistochemistry verified the expression of Dact2 in the tooth epithelium, which correlated with Pitx2 epithelial expression. Dact2 loss of function and PITX2 gain of function studies reveal a feedback mechanism for controlling Dact2 expression. Pitx2 endogenously activates Dact2 expression and Dact2 feeds back to repress Pitx2 transcriptional activity. A Topflash reporter system was employed showing PITX2 activation of Wnt signaling, which is attenuated by Dact2. Transient transfections demonstrate the inhibitory effect of Dact2 on critical dental epithelial differentiation factors during tooth development. Dact2 significantly inhibits PITX2 activation of the Dlx2 and amelogenin promoters. Multiple lines of evidence conclude the inhibition is achieved by the physical interaction between Dact2 and Pitx2 proteins. The loss of function of Dact2 also reveals increased cell proliferation due to up-regulated Wnt downstream genes, cyclinD1 and cyclinD2. In summary, we have identified a novel role for Dact2 as an inhibitor of the canonical Wnt pathway in embryonic tooth development through its regulation of cell proliferation and differentiation.

  4. Wnt16 Signaling Is Required for IL-1β-Induced Matrix Metalloproteinase-13-Regulated Proliferation of Human Stem Cell-Derived Osteoblastic Cells.

    Science.gov (United States)

    Ozeki, Nobuaki; Mogi, Makio; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki; Kawai, Rie; Kondo, Ayami; Nakata, Kazuhiko

    2016-02-06

    We established a differentiation method for homogeneous α7 integrin-positive human skeletal muscle stem cell (α7⁺hSMSC)-derived osteoblast-like (α7⁺hSMSC-OB) cells, and found that interleukin (IL)-1β induces matrix metalloproteinase (MMP)-13-regulated proliferation of these cells. These data suggest that MMP-13 plays a potentially unique physiological role in the regeneration of osteoblast-like cells. Here, we examined whether up-regulation of MMP-13 activity by IL-1β was mediated by Wingless/int1 (Wnt) signaling and increased the proliferation of osteoblast-like cells. IL-1β increased the mRNA and protein levels of Wnt16 and the Wnt receptor Lrp5/Fzd2. Exogenous Wnt16 was found to increase MMP-13 mRNA, protein and activity, and interestingly, the proliferation rate of these cells. Treatment with small interfering RNAs against Wnt16 and Lrp5 suppressed the IL-1β-induced increase in cell proliferation. We revealed that a unique signaling cascade IL-1β→Wnt16→Lrp5→MMP-13, was intimately involved in the proliferation of osteoblast-like cells, and suggest that IL-1β-induced MMP-13 expression and changes in cell proliferation are regulated by Wnt16.

  5. Myeloperoxidase-mediated protein lysine oxidation generates 2-aminoadipic acid and lysine nitrile in vivo.

    Science.gov (United States)

    Lin, Hongqiao; Levison, Bruce S; Buffa, Jennifer A; Huang, Ying; Fu, Xiaoming; Wang, Zeneng; Gogonea, Valentin; DiDonato, Joseph A; Hazen, Stanley L

    2017-03-01

    Recent studies reveal 2-aminoadipic acid (2-AAA) is both elevated in subjects at risk for diabetes and mechanistically linked to glucose homeostasis. Prior studies also suggest enrichment of protein-bound 2-AAA as an oxidative post-translational modification of lysyl residues in tissues associated with degenerative diseases of aging. While in vitro studies suggest redox active transition metals or myeloperoxidase (MPO) generated hypochlorous acid (HOCl) may produce protein-bound 2-AAA, the mechanism(s) responsible for generation of 2-AAA during inflammatory diseases are unknown. In initial studies we observed that traditional acid- or base-catalyzed protein hydrolysis methods previously employed to measure tissue 2-AAA can artificially generate protein-bound 2-AAA from an alternative potential lysine oxidative product, lysine nitrile (LysCN). Using a validated protease-based digestion method coupled with stable isotope dilution LC/MS/MS, we now report protein bound 2-AAA and LysCN are both formed by hypochlorous acid (HOCl) and the MPO/H 2 O 2 /Cl - system of leukocytes. At low molar ratio of oxidant to target protein N ε -lysine moiety, 2-AAA is formed via an initial N ε -monochloramine intermediate, which ultimately produces the more stable 2-AAA end-product via sequential generation of transient imine and semialdehyde intermediates. At higher oxidant to target protein N ε -lysine amine ratios, protein-bound LysCN is formed via initial generation of a lysine N ε -dichloramine intermediate. In studies employing MPO knockout mice and an acute inflammation model, we show that both free and protein-bound 2-AAA, and in lower yield, protein-bound LysCN, are formed by MPO in vivo during inflammation. Finally, both 2-AAA and to lesser extent LysCN are shown to be enriched in human aortic atherosclerotic plaque, a tissue known to harbor multiple MPO-catalyzed protein oxidation products. Collectively, these results show that MPO-mediated oxidation of protein lysyl

  6. Characterization of hapten-protein conjugates: antibody generation and immunoassay development for chlorophenoxyacetic acid pesticides.

    Science.gov (United States)

    Boro, Robin C; Singh, K Vikas; Suri, C Raman

    2009-01-01

    The generation of specific and sensitive antibodies against small molecules is greatly dependent upon the characteristics of the hapten-protein conjugates. In this study, we report a new fluorescence-based method for the characterization of hapten-protein conjugates. The method is based on an effect promoted by hapten-protein conjugation density upon the fluorescence intensity of the intrinsic tryptophan chromophore molecules of the protein. The proposed methodology is applied to quantify the hapten-protein conjugation density for two different chlorophenoxyacetic acid pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB), coupled to carrier protein. Highly sensitive anti-2,4-D and anti-2,4-DB antibodies were obtained using these well-characterized hapten-protein conjugates. The generated antibodies were used in an immunoassay format demonstrating inhibitory concentration (IC50) values equal to 30 and 7 ng/mL for 2,4-D and 2,4-DB, respectively. Linearity was observed in the concentration range between 0.1-500 nglmL with LODs around 4 and 3 ng/mL for 2,4-D and 2,4-DB, respectively, in standard water samples. The proposed method was successfully applied for the determination of the extent of hapten-protein conjugation to produce specific antibodies for immunoassay development against pesticides.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Alzheimer disease: crosstalk between the canonical Wnt/beta-catenin pathway and PPARs alpha and gamma

    Directory of Open Access Journals (Sweden)

    Alexandre VALLEE

    2016-10-01

    Full Text Available 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 . 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.

  9. Wnt signaling: the β-cat(enin)'s meow

    OpenAIRE

    Bauer, Matthieu; Willert, Karl

    2012-01-01

    This Perspective discusses the work from the Basler laboratory (published in the December 15, 2011, issue), in which they create a β-catenin mutant form that maintains its adhesion function but specifically blocks its Wnt signaling activity. Bauer and Willert discuss this specific dissection of Wnt/β-catenin signaling activity and the surprising new insights into Wnt signaling.

  10. 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.

  11. Endogenous WNT Signals Mediate BMP-Induced and Spontaneous Differentiation of Epiblast Stem Cells and Human Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    Dorota Kurek

    2015-01-01

    Full Text Available Therapeutic application of human embryonic stem cells (hESCs requires precise control over their differentiation. However, spontaneous differentiation is prevalent, and growth factors induce multiple cell types; e.g., the mesoderm inducer BMP4 generates both mesoderm and trophoblast. Here we identify endogenous WNT signals as BMP targets that are required and sufficient for mesoderm induction, while trophoblast induction is WNT independent, enabling the exclusive differentiation toward either lineage. Furthermore, endogenous WNT signals induce loss of pluripotency in hESCs and their murine counterparts, epiblast stem cells (EpiSCs. WNT inhibition obviates the need to manually remove differentiated cells to maintain cultures and improves the efficiency of directed differentiation. In EpiSCs, WNT inhibition stabilizes a pregastrula epiblast state with novel characteristics, including the ability to contribute to blastocyst chimeras. Our findings show that endogenous WNT signals function as hidden mediators of growth factor-induced differentiation and play critical roles in the self-renewal of hESCs and EpiSCs.

  12. Wnt5a Increases the Glycolytic Rate and the Activity of the Pentose Phosphate Pathway in Cortical Neurons.

    Science.gov (United States)

    Cisternas, Pedro; Salazar, Paulina; Silva-Álvarez, Carmen; Barros, L Felipe; Inestrosa, Nibaldo C

    In the last few years, several reports have proposed that Wnt signaling is a general metabolic regulator, suggesting a role for this pathway in the control of metabolic flux. Wnt signaling is critical for several neuronal functions, but little is known about the correlation between this pathway and energy metabolism. The brain has a high demand for glucose, which is mainly used for energy production. Neurons use energy for highly specific processes that require a high energy level, such as maintaining the electrical potential and synthesizing neurotransmitters. Moreover, an important metabolic impairment has been described in all neurodegenerative disorders. Despite the key role of glucose metabolism in the brain, little is known about the cellular pathways involved in regulating this process. We report here that Wnt5a induces an increase in glucose uptake and glycolytic rate and an increase in the activity of the pentose phosphate pathway; the effects of Wnt5a require the intracellular generation of nitric oxide. Our data suggest that Wnt signaling stimulates neuronal glucose metabolism, an effect that could be important for the reported neuroprotective role of Wnt signaling in neurodegenerative disorders.

  13. Wnt5a Increases the Glycolytic Rate and the Activity of the Pentose Phosphate Pathway in Cortical Neurons

    Directory of Open Access Journals (Sweden)

    Pedro Cisternas

    2016-01-01

    Full Text Available In the last few years, several reports have proposed that Wnt signaling is a general metabolic regulator, suggesting a role for this pathway in the control of metabolic flux. Wnt signaling is critical for several neuronal functions, but little is known about the correlation between this pathway and energy metabolism. The brain has a high demand for glucose, which is mainly used for energy production. Neurons use energy for highly specific processes that require a high energy level, such as maintaining the electrical potential and synthesizing neurotransmitters. Moreover, an important metabolic impairment has been described in all neurodegenerative disorders. Despite the key role of glucose metabolism in the brain, little is known about the cellular pathways involved in regulating this process. We report here that Wnt5a induces an increase in glucose uptake and glycolytic rate and an increase in the activity of the pentose phosphate pathway; the effects of Wnt5a require the intracellular generation of nitric oxide. Our data suggest that Wnt signaling stimulates neuronal glucose metabolism, an effect that could be important for the reported neuroprotective role of Wnt signaling in neurodegenerative disorders.

  14. Genotype-phenotype analysis of a rare type of osteogenesis imperfecta in four Chinese families with WNT1 mutations.

    Science.gov (United States)

    Liu, Yi; Song, Lijie; Ma, Doudou; Lv, Fang; Xu, Xiaojie; Wang, Jianyi; Xia, Weibo; Jiang, Yan; Wang, Ou; Song, Yuwen; Xing, Xiaoping; Asan; Li, Mei

    2016-10-01

    Osteogenesis imperfecta (OI) is a rare inherited disease characterized by increased bone fragility and vulnerability to fractures. Recently, WNT1 is identified as a new candidate gene for OI, here we detect pathogenic mutations in WNT1 and analyze the genotype-phenotype association in four Chinese families with OI. We designed a targeted next generation sequencing panel with known fourteen OI-related genes. We applied the approach to detect pathogenic mutations in OI patients and confirmed the mutations with Sanger sequencing and cosegregation analysis. Clinical fractures, bone mineral density (BMD) and the other clinical manifestations were evaluated. We also observed the effects of bisphosphonates in OI patients with WNT1 mutations. Four compound heterozygous mutations (c.110T>C; c.505 G>T; c. 385G>A; c.506 G>A) in WNT1 were detected in three unrelated families. These four mutations had not been reported yet. A recurrent homozygous mutation (c.506dupG) was identified in the other two families. These patients had moderate to severe OI, white to blue sclera, absence of dentinogenesis imperfecta and no brain malformation. We did not observe clear genotype-phenotype correlation in WNT1 mutated OI patients. Though bisphosphonates increased BMD in WNT1 related OI patients, height did not increase and fracture continued. We reported four novel heterozygous variants and confirmed a previous reported WNT1 mutation in four Chinese families with a clinical diagnosis of OI. Our study expanded OI spectrum and confirmed moderate to severe bone fragility induced by WNT1 defects. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. The vitamin D receptor is required for activation of cWnt and hedgehog signaling in keratinocytes.

    Science.gov (United States)

    Lisse, Thomas S; Saini, Vaibhav; Zhao, Hengguang; Luderer, Hilary F; Gori, Francesca; Demay, Marie B

    2014-10-01

    Alopecia (hair loss) in vitamin D receptor (VDR)-null mice is due to absence of ligand-independent actions of the VDR that are required for initiation of postmorphogenic hair cycles. Investigations were undertaken to determine whether the VDR is required for the induction of signaling pathways that play an important role in this process. The induction of cWnt and hedgehog target genes that characterizes early anagen was found to be dramatically attenuated in VDR(-/-) mice, relative to wild-type (WT) mice. To determine whether this reflects impaired responsiveness to cWnt ligands, in vitro studies were performed in primary keratinocytes. These studies demonstrated impaired induction of cWnt target genes in response to Wnt3a in VDR(-/-) keratinocytes, relative to wild-type keratinocytes. Chromatin immunoprecipitation analyses revealed that the VDR was recruited to the regulatory regions of cWnt and hedgehog target genes in WT keratinocytes but not in VDR(-/-) or Lef1(-/-) keratinocytes. Lef1 was enriched on these same regulatory regions in WT keratinocytes but not in VDR(-/-) keratinocytes. In vivo studies were performed to determine whether activation of the hedgehog pathway could bypass the defect in cWnt signaling observed in the absence of the unliganded VDR. In WT, but not VDR(-/-), mice, hedgehog agonist treatment resulted in an induction of cWnt and hedgehog target genes and the generation of mature anagen hair follicles. Thus, these studies demonstrate that the unliganded VDR interacts with regulatory regions in the cWnt and hedgehog target genes and is required for the induction of these pathways during the postnatal hair cycle.

  16. WNT-er is coming’: WNT signalling in chronic lung diseases

    Science.gov (United States)

    Baarsma, H A

    2017-01-01

    Chronic lung diseases represent a major public health problem with only limited therapeutic options. An important unmet need is to identify compounds and drugs that target key molecular pathways involved in the pathogenesis of chronic lung diseases. Over the last decade, there has been extensive interest in investigating Wingless/integrase-1 (WNT) signalling pathways; and WNT signal alterations have been linked to pulmonary disease pathogenesis and progression. Here, we comprehensively review the cumulative evidence for WNT pathway alterations in chronic lung pathologies, including idiopathic pulmonary fibrosis, pulmonary arterial hypertension, asthma and COPD. While many studies have focused on the canonical WNT/β-catenin signalling pathway, recent reports highlight that non-canonical WNT signalling may also significantly contribute to chronic lung pathologies; these studies will be particularly featured in this review. We further discuss recent advances uncovering the role of WNT signalling early in life, the potential of pharmaceutically modulating WNT signalling pathways and highlight (pre)clinical studies describing promising new therapies for chronic lung diseases. PMID:28416592

  17. Dietary protein is associated with musculoskeletal health independently of dietary pattern: the Framingham Third Generation Study.

    Science.gov (United States)

    Mangano, Kelsey M; Sahni, Shivani; Kiel, Douglas P; Tucker, Katherine L; Dufour, Alyssa B; Hannan, Marian T

    2017-03-01

    Background: Above-average dietary protein, as a single nutrient, improves musculoskeletal health. Evaluating the link between dietary protein and musculoskeletal health from a whole-diet perspective is important, as dietary guidelines focus on dietary patterns. Objective: We examined the prospective association of novel dietary protein food clusters (derived from established dietary pattern techniques) with appendicular lean mass (ALM), quadriceps strength (QS), and bone mineral density (BMD) in 2986 men and women, aged 19-72 y, from the Framingham Third Generation Study. Design: Total protein intake was estimated by food-frequency questionnaire in 2002-2005. A cluster analysis was used to classify participants into mutually exclusive groups, which were determined by using the percentage of contribution of food intake to overall protein intake. General linear modeling was used to 1 ) estimate the association between protein intake (grams per day) and BMD, ALM, appendicular lean mass normalized for height (ALM/ht 2 ), and QS (2008-2011) and to 2 ) calculate adjusted least-squares mean outcomes across quartiles of protein (grams per day) and protein food clusters. Results: The mean ± SD age of subjects was 40 ± 9 y; 82% of participants met the Recommended Daily Allowance (0.8 g · kg body weight -1 · d -1 ). The following 6 dietary protein food clusters were identified: fast food and full-fat dairy, fish, red meat, chicken, low-fat milk, and legumes. BMD was not different across quartiles of protein intake ( P -trend range = 0.32-0.82); but significant positive trends were observed for ALM, ALM/ht 2 ( P dietary protein is associated with ALM and QS but not with BMD. In this study, dietary protein food patterns do not provide further insight into beneficial protein effects on muscle outcomes. © 2017 American Society for Nutrition.

  18. Multiple isoforms of β-TrCP display differential activities in the regulation of Wnt signaling

    Science.gov (United States)

    Seo, Eunjeong; Kim, Hyunjoon; Kim, Rokki; Yun, Sangmoon; Kim, Minseong; Han, Jin-Kwan; Costantini, Frank; Jho, Eek-hoon

    2008-01-01

    The F-box proteins β-TrCP 1 and 2 (β-transducin repeat protein) have 2 and 3 isoforms, respectively, due to alternative splicing of exons encoding the N-terminal region. We identified an extra exon in between the previously known exons 1 and 2 of β-TrCP1 and β-TrCP2. Interestingly, sequence analysis suggested that many more isoforms are produced than previously identified, via the alternative splicing of all possible combination of exons II to V of β-TrCP1 and exons II to IV of β-TrCP2. Different mouse tissues show specific expression patterns of the isoforms, and the level of expression of the isoform that has been used in most published papers was very low. Yeast two-hybrid assays show that β-TrCP1 isoforms containing exon III, which are the most highly expressed isoforms in most tissues, do not interact with Skp1. Indirect immunofluorescence analysis of transiently expressed β-TrCP1 isoforms suggests that the presence of exon III causes β-TrCP1 to localize in nuclei. Consistent with the above findings, isoforms including exon III showed a reduced ability to block ectopic embryonic axes induced via injection of Wnt8 or β-catenin in Xenopus embryos. Overall, our data suggest that isoforms of β-TrCPs generated by alternative splicing may have different biological roles. PMID:18929646

  19. Generation of Oxygen Free Radicals by Proflavine: Implication in Protein Degradation

    Directory of Open Access Journals (Sweden)

    Mansour K.M. Gatasheh

    2017-07-01

    Full Text Available Proflavine, an acridine dye, is a known DNA intercalating agent. In the present study, we show that proflavine alone on photoillumination can generate reactive oxygen species (ROS. These proflavine-derived ROS cause damage to proteins, and this effect is enhanced when the divalent metal ion Cu (II is included in the reaction. Bathocuproine, a specific Cu (I sequestering agent, when present in the reaction mixture containing Cu (II, was found to inhibit the protein degradation, showing that Cu (I is an essential intermediate in the reaction. The effect of several scavengers of ROS such as superoxide dismutase, sodium azide, potassium iodide, and thiourea were examined on the protein damaging reaction. Potassium iodide was found to be the most effective in inhibiting protein damage followed by sodium azide and thiourea. Our results indicate the involvement of superoxide, singlet oxygen, triplet oxygen, and hydroxyl radicals in proflavine-induced damage to proteins.

  20. Generating functional analysis of complex formation and dissociation in large protein interaction networks

    International Nuclear Information System (INIS)

    Coolen, A C C; Rabello, S

    2009-01-01

    We analyze large systems of interacting proteins, using techniques from the non-equilibrium statistical mechanics of disordered many-particle systems. Apart from protein production and removal, the most relevant microscopic processes in the proteome are complex formation and dissociation, and the microscopic degrees of freedom are the evolving concentrations of unbound proteins (in multiple post-translational states) and of protein complexes. Here we only include dimer-complexes, for mathematical simplicity, and we draw the network that describes which proteins are reaction partners from an ensemble of random graphs with an arbitrary degree distribution. We show how generating functional analysis methods can be used successfully to derive closed equations for dynamical order parameters, representing an exact macroscopic description of the complex formation and dissociation dynamics in the infinite system limit. We end this paper with a discussion of the possible routes towards solving the nontrivial order parameter equations, either exactly (in specific limits) or approximately.

  1. Protein Z efficiently depletes thrombin generation in disseminated intravascular coagulation with poor prognosis.

    Science.gov (United States)

    Lee, Nuri; Kim, Ji-Eun; Gu, Ja-Yoon; Yoo, Hyun Ju; Kim, Inho; Yoon, Sung-Soo; Park, Seonyang; Han, Kyou-Sup; Kim, Hyun Kyung

    2016-01-01

    Disseminated intravascular coagulation (DIC) is characterized by consumption of coagulation factors and anticoagulants. Thrombin generation assay (TGA) gives useful information about global hemostatic status. We developed a new TGA system that anticoagulant addition can deplete thrombin generation in plasma, which may reflect defective anticoagulant system in DIC. TGAs were measured on the calibrated automated thrombogram with and without thrombomodulin or protein Z in 152 patients who were suspected of having DIC, yielding four parameters including lag time, endogenous thrombin potential, peak thrombin and time-to-peak in each experiment. Nonsurvivors showed significantly prolonged lag time and time-to-peak in TGA-protein Z system, which was performed with added protein Z. In multivariate Cox regression analysis, lag time and time-to-peak in TGA system were significant independent prognostic factors. In TGA-protein Z system, lag time and time-to-peak were revealed as independent prognostic factors of DIC. Protein Z addition could potentiate its anticoagulant effect in DIC with poor prognosis, suggesting the presence of defective protein Z system. The prolonged lag time and time-to-peak in both TGA and TGA-protein Z systems are expected to be used as independent prognostic factors of DIC.

  2. Identification of an immunogenic protein of Giardia lamblia using monoclonal antibodies generated from infected mice

    Directory of Open Access Journals (Sweden)

    Jael Quintero

    2013-08-01

    Full Text Available The humoral immune response plays an important role in the clearance of Giardia lamblia. However, our knowledge about the specific antigens of G. lamblia that induce a protective immune response is limited. The purpose of this study was to identify and characterise the immunogenic proteins of G. lamblia in a mouse model. We generated monoclonal antibodies (moAbs specific to G. lamblia (1B10, 2C9.D11, 3C10.E5, 3D10, 5G8.B5, 5F4, 4C7, 3C5 and 3C6 by fusing splenocytes derived from infected mice. Most of these moAbs recognised a band of ± 71 kDa (5G8 protein and this protein was also recognised by serum from the infected mice. We found that the moAbs recognised conformational epitopes of the 5G8 protein and that this antigen is expressed on the cell surface and inside trophozoites. Additionally, antibodies specific to the 5G8 protein induced strong agglutination (> 70-90% of trophozoites. We have thus identified a highly immunogenic antigen of G. lamblia that is recognised by the immune system of infected mice. In summary, this study describes the identification and partial characterisation of an immunogenic protein of G. lamblia. Additionally, we generated a panel of moAbs specific for this protein that will be useful for the biochemical and immunological characterisation of this immunologically interesting Giardia molecule.

  3. Wnt and β-Catenin Signaling and Skeletal Muscle Myogenesis in Response to Muscle Damage and Resistance Exercise and Training

    Directory of Open Access Journals (Sweden)

    Dan Newmire

    2015-10-01

    Full Text Available The factors that regulate skeletal muscle hypertrophy in human adults in response to resistance training (RT has largely focused on endogenous endocrine responses. However, the endocrine response to RT as having an obligatory role in muscle hypertrophy has come under scrutiny, as other mechanisms and pathways seem to also be involved in up-regulating muscle protein synthesis (MPS. Skeletal muscle myogenesis is a multifactorial process of tissue growth and repair in response to resistance training is regulated by many factors.  As a result, satellite cell-fused myogenesis is a possible factor in skeletal muscle regeneration and hypertrophy in response to RT.  The Wnt family ligands interact with various receptors and activate different downstream signaling pathways and have been classified as either canonical (β-catenin dependent or non-canonical (β-catenin independent.  Wnt is secreted from numerous tissues in a paracrine fashion. The Wnt/β-catenin signaling pathway is a highly-regulated and intricate pathway that is essential to skeletal muscle myogenesis.  The canonical Wnt/β-catenin pathway may influence satellite cells to myogenic commitment, differentiation, and fusion into muscle fibers in response to injury or trauma, self-renewal, and normal basal turnover.  The current literature has shown that, in response mechanical overload from acute resistance exercise and chronic resistance training, that the Wnt/β-catenin signaling pathway is stimulated which may actuate the process of muscle repair and hypertrophy in response to exercise-induced muscle damage. The purpose of this review is to elaborate on the Wnt/β-catenin signaling  pathway, the current literature investigating the relationship of the Wnt/β-catenin pathway and its effects on myogenesis is response to muscle damage and resistance exercise and training.      Keywords: skeletal muscle, hypertrophy, myogenesis, cell signaling, protein synthesis, resistance

  4. Autophagy suppresses proliferation of HepG2 cells via inhibiting glypican-3/wnt/β-catenin signaling

    Directory of Open Access Journals (Sweden)

    Hu P

    2018-01-01

    Full Text Available Pei Hu,1,2 Bin Cheng,3 Yulin He,3 Zhiqiang Wei,3 Dongfang Wu,1 Zhongji Meng3,4 1Department of Pharmacy, Zhongnan Hospital of Wuhan University, Wuhan, 2Department of Clinical Laboratory Medicine, 3Institute of Biomedical Research, 4Department of Infectious Disease, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China Introduction: Autophagy plays an important role in the growth and survival of hepatocellular carcinoma (HCC cells through several target proteins or signaling pathways. Glypican-3 (GPC3 is a new reliable HCC marker, which is involved in tumor growth in HCC, primarily mediated by wnt/β-catenin signaling. Objective: The present study aimed to identify the role of autophagy in the proliferation of HepG2 cells through GPC3/wnt/β-catenin signaling. Results and discussion: Results demonstrated that induction of autophagy by nutrition starvation and rapamycin treatment led to the downregulation of GPC3 expression in HepG2 cells, accompanied by the decreased expression of wnt downstream target genes (β-catenin, c-myc and cyclin D1. On the other hand, inhibition of autophagy by 3-methyl adenine (3-MA could rescue rapamycin-directed downregulation of GPC3 and wnt/β-catenin target genes and augment the proliferation of HepG2 cells. Furthermore, interference of GPC3 by siRNA suppressed wnt/β-catenin signaling and attenuated 3-MA stimulation of HepG2 cell proliferation. More interestingly, the mRNA of GPC3 remained unchanged when the protein levels of GPC3 were decreased by autophagy activation, suggesting that induction of autophagy may accelerate the degradation of GPC3. Conclusion: These results suggest that autophagy suppresses proliferation of HepG2 cells partially by inhibition of GPC3/wnt/β-catenin signaling. Keywords: hepatocellular carcinoma, glypican-3, autophagy, proliferation, wnt/β-catenin signaling

  5. MGAT1 is a novel transcriptional target of Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Akiva, Izzet; Birgül Iyison, Necla

    2018-01-08

    The Wnt/β-catenin signaling pathway is an evolutionary conserved pathway, which has important functions in vertebrate early development, axis formation, cellular proliferation and morphogenesis. Additionally, Wnt/β-catenin signaling pathway is one of the most important intracellular pathways that controls cancer progression. To date most of the identified targets of this pathway are shown to harbor tumorigenic properties. We previously showed that Mannosyl glycoprotein acetylglucosaminyl-transferase (MGAT1) enzyme is among the Wnt/β-catenin signaling putative target genes in hepatocellular carcinoma cell lines (Huh7). MGAT1 protein levels were determined by Western Blotting from Huh7 cell lines in which Wnt/β-catenin pathway was activated by means of different approaches such as LiCl treatment and mutant β-catenin overexpression. Luciferase reporter assay was used to analyze the promoter activity of MGAT1. The mRNA levels of MGAT1 were determined by quantitative real-time PCR from Huh7 cells that were treated with either Wnt agonist or GSK-3β inhibitor. Wound healing and XTT cell proliferation assays were performed in order to determine the proliferation and migration capacities of MGAT1 overexpressing stable Huh7 cells. Finally, xenograft experiments were carried out to measure the tumor formation capacities in vivo. In this study we showed that the activation of Wnt/β-catenin pathway culminates in the upregulation of MGAT1 enzyme both at transcriptional and post-transcriptional levels. We also showed that overexpression of the β-catenin gene (CTNNB1) increased the promoter activity of MGAT1. We applied a set of complementary approaches to elucidate the functional importance of MGAT1 as a vital target of Wnt/β-catenin signaling in Huh7 cells. Our analyses related to cell proliferation and migration assays showed that in comparison to the control cells, MGAT1 expressing Huh7 cells have greater proliferative and invasive capabilities. Furthermore, the

  6. Wnt signaling in triple-negative breast cancer

    Science.gov (United States)

    Pohl, SÖ-G; Brook, N; Agostino, M; Arfuso, F; Kumar, A P; Dharmarajan, A

    2017-01-01

    Wnt signaling regulates a variety of cellular processes, including cell fate, differentiation, proliferation and stem cell pluripotency. Aberrant Wnt signaling is a hallmark of many cancers. An aggressive subtype of breast cancer, known as triple-negative breast cancer (TNBC), demonstrates dysregulation in canonical and non-canonical Wnt signaling. In this review, we summarize regulators of canonical and non-canonical Wnt signaling, as well as Wnt signaling dysfunction that mediates the progression of TNBC. We review the complex molecular nature of TNBC and the emerging therapies that are currently under investigation for the treatment of this disease. PMID:28368389

  7. Plasmonic photocatalyst-like fluorescent proteins for generating reactive oxygen species

    Science.gov (United States)

    Leem, Jung Woo; Kim, Seong-Ryul; Choi, Kwang-Ho; Kim, Young L.

    2018-03-01

    The recent advances in photocatalysis have opened a variety of new possibilities for energy and biomedical applications. In particular, plasmonic photocatalysis using hybridization of semiconductor materials and metal nanoparticles has recently facilitated the rapid progress in enhancing photocatalytic efficiency under visible or solar light. One critical underlying aspect of photocatalysis is that it generates and releases reactive oxygen species (ROS) as intermediate or final products upon light excitation or activation. Although plasmonic photocatalysis overcomes the limitation of UV irradiation, synthesized metal/semiconductor nanomaterial photocatalysts often bring up biohazardous and environmental issues. In this respect, this review article is centered in identifying natural photosensitizing organic materials that can generate similar types of ROS as those of plasmonic photocatalysis. In particular, we propose the idea of plasmonic photocatalyst-like fluorescent proteins for ROS generation under visible light irradiation. We recapitulate fluorescent proteins that have Type I and Type II photosensitization properties in a comparable manner to plasmonic photocatalysis. Plasmonic photocatalysis and protein photosensitization have not yet been compared systemically in terms of ROS photogeneration under visible light, although the phototoxicity and cytotoxicity of some fluorescent proteins are well recognized. A comprehensive understanding of plasmonic photocatalyst-like fluorescent proteins and their potential advantages will lead us to explore new environmental, biomedical, and defense applications.

  8. Photo-oxidation of cells generates long-lived intracellular protein peroxides

    DEFF Research Database (Denmark)

    Wright, Adam; Hawkins, Clare Louise; Davies, Michael Jonathan

    2003-01-01

    Singlet oxygen is generated by several cellular, enzymatic, and chemical reactions as well as by exposure to UV or visible light in the presence of a sensitizer. Consequently, this oxidant has been proposed to be a damaging agent many pathologies. Proteins are major targets for singlet oxygen as ...

  9. The function and evolution of Wnt genes in arthropods.

    Science.gov (United States)

    Murat, Sophie; Hopfen, Corinna; McGregor, Alistair P

    2010-11-01

    Wnt signalling is required for a wide range of developmental processes, from cleavage to patterning and cell migration. There are 13 subfamilies of Wnt ligand genes and this diverse repertoire appeared very early in metazoan evolution. In this review, we first summarise the known Wnt gene repertoire in various arthropods. Insects appear to have lost several Wnt subfamilies, either generally, such as Wnt3, or in lineage specific patterns, for example, the loss of Wnt7 in Anopheles. In Drosophila and Acyrthosiphon, only seven and six Wnt subfamilies are represented, respectively; however, the finding of nine Wnt genes in Tribolium suggests that arthropods had a larger repertoire ancestrally. We then discuss what is currently known about the expression and developmental function of Wnt ligands in Drosophila and other insects in comparison to other arthropods, such as the spiders Achaearanea and Cupiennius. We conclude that studies of Wnt genes have given us much insight into the developmental roles of some of these ligands. However, given the frequent loss of Wnt genes in insects and the derived development of Drosophila, further studies of these important genes are required in a broader range of arthropods to fully understand their developmental function and evolution. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Role of the Wnt signaling molecules in the tooth

    Directory of Open Access Journals (Sweden)

    Masato Tamura, PhD, DDS

    2016-11-01

    Full Text Available Wnt signaling plays a central role in many processes during embryonic development and adult homeostasis. At least 19 types of Wnt ligands, receptors, transducers, transcription factors, and antagonists have been identified in mammals. Two distinct Wnt signaling pathways, the canonical signaling pathway and the noncanonical signaling pathway, have been described. Some Wnt signaling pathway components are expressed in the dental epithelium and mesenchyme during tooth development in humans and mice. Functional studies and experimental analysis of relevant animal models confirm the effects of Wnt signaling pathway on the regulation of developing tooth formation and adult tooth homeostasis. Mutations in some Wnt signaling pathway components have been identified in syndromic and non-syndromic tooth agenesis. This review provides an overview of progress in elucidating the role of Wnt signaling pathway components in the tooth and the resulting possibilities for therapeutic development.

  11. 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...... and appears to be due to an inducible interaction between LRP5 and the insulin receptor as demonstrated by co-immunoprecipitation. These data demonstrate that Wnt and insulin signaling pathways exhibit cross-talk at multiple levels. Wnt induces phosphorylation of Akt, ERK1/2, and GSK3β, and this is dependent...

  12. Broadband photon pair generation in green fluorescent proteins through spontaneous four-wave mixing

    Science.gov (United States)

    Shi, Siyuan; Thomas, Abu; Corzo, Neil V.; Kumar, Prem; Huang, Yuping; Lee, Kim Fook

    2016-04-01

    Recent studies in quantum biology suggest that quantum mechanics help us to explore quantum processes in biological system. Here, we demonstrate generation of photon pairs through spontaneous four-wave mixing process in naturally occurring fluorescent proteins. We develop a general empirical method for analyzing the relative strength of nonlinear optical interaction processes in five different organic fluorophores. Our results indicate that the generation of photon pairs in green fluorescent proteins is subject to less background noises than in other fluorophores, leading to a coincidence-to-accidental ratio ~145. As such proteins can be genetically engineered and fused to many biological cells, our experiment enables a new platform for quantum information processing in a biological environment such as biomimetic quantum networks and quantum sensors.

  13. Nitric Oxide Mediates Crosstalk between Interleukin 1β and WNT Signaling in Primary Human Chondrocytes by Reducing DKK1 and FRZB Expression.

    Science.gov (United States)

    Zhong, Leilei; Schivo, Stefano; Huang, Xiaobin; Leijten, Jeroen; Karperien, Marcel; Post, Janine N

    2017-11-22

    Interleukin 1 beta (IL1β) and Wingless-Type MMTV Integration Site Family (WNT) signaling are major players in Osteoarthritis (OA) pathogenesis. Despite having a large functional overlap in OA onset and development, the mechanism of IL1β and WNT crosstalk has remained largely unknown. In this study, we have used a combination of computational modeling and molecular biology to reveal direct or indirect crosstalk between these pathways. Specifically, we revealed a mechanism by which IL1β upregulates WNT signaling via downregulating WNT antagonists, DKK1 and FRZB. In human chondrocytes, IL1β decreased the expression of Dickkopf-1 (DKK1) and Frizzled related protein (FRZB) through upregulation of nitric oxide synthase (iNOS), thereby activating the transcription of WNT target genes. This effect could be reversed by iNOS inhibitor 1400W, which restored DKK1 and FRZB expression and their inhibitory effect on WNT signaling. In addition, 1400W also inhibited both the matrix metalloproteinase (MMP) expression and cytokine-induced apoptosis. We concluded that iNOS/NO play a pivotal role in the inflammatory response of human OA through indirect upregulation of WNT signaling. Blocking NO production may inhibit the loss of the articular phenotype in OA by preventing downregulation of the expression of DKK1 and FRZB.

  14. Anti-Sclerostin antibody inhibits internalization of Sclerostin and Sclerostin-mediated antagonism of Wnt/LRP6 signaling.

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    Maarten van Dinther

    Full Text Available Sclerosteosis is a rare high bone mass disease that is caused by inactivating mutations in the SOST gene. Its gene product, Sclerostin, is a key negative regulator of bone formation and might therefore serve as a target for the anabolic treatment of osteoporosis. The exact molecular mechanism by which Sclerostin exerts its antagonistic effects on Wnt signaling in bone forming osteoblasts remains unclear. Here we show that Wnt3a-induced transcriptional responses and induction of alkaline phosphatase activity, an early marker of osteoblast differentiation, require the Wnt co-receptors LRP5 and LRP6. Unlike Dickkopf1 (DKK1, Sclerostin does not inhibit Wnt-3a-induced phosphorylation of LRP5 at serine 1503 or LRP6 at serine 1490. Affinity labeling of cell surface proteins with [(125I]Sclerostin identified LRP6 as the main specific Sclerostin receptor in multiple mesenchymal cell lines. When cells were challenged with Sclerostin fused to recombinant green fluorescent protein (GFP this was internalized, likely via a Clathrin-dependent process, and subsequently degraded in a temperature and proteasome-dependent manner. Ectopic expression of LRP6 greatly enhanced binding and cellular uptake of Sclerostin-GFP, which was reduced by the addition of an excess of non-GFP-fused Sclerostin. Finally, an anti-Sclerostin antibody inhibited the internalization of Sclerostin-GFP and binding of Sclerostin to LRP6. Moreover, this antibody attenuated the antagonistic activity of Sclerostin on canonical Wnt-induced responses.

  15. Non-canonical Wnt signaling regulates cell polarity in female reproductive tract development via van gogh-like 2

    Science.gov (United States)

    vandenBerg, Alysia L.; Sassoon, David A.

    2009-01-01

    Summary Wnt signaling effectors direct the development and adult remodeling of the female reproductive tract (FRT); however, the role of non-canonical Wnt signaling has not been explored in this tissue. The non-canonical Wnt signaling protein van gogh-like 2 is mutated in loop-tail (Lp) mutant mice (Vangl2Lp), which display defects in multiple tissues. We find that Vangl2Lp mutant uterine epithelium displays altered cell polarity, concommitant with changes in cytoskeletal actin and scribble (scribbled, Scrb1) localization. The postnatal mutant phenotype is an exacerbation of that seen at birth, exhibiting more smooth muscle and reduced stromal mesenchyme. These data suggest that early changes in cell polarity have lasting consequences for FRT development. Furthermore, Vangl2 is required to restrict Scrb1 protein to the basolateral epithelial membrane in the neonatal uterus, and an accumulation of fibrillar-like structures observed by electron microscopy in Vangl2Lp mutant epithelium suggests that mislocalization of Scrb1 in mutants alters the composition of the apical face of the epithelium. Heterozygous and homozygous Vangl2Lp mutant postnatal tissues exhibit similar phenotypes and polarity defects and display a 50% reduction in Wnt7a levels, suggesting that the Vangl2Lp mutation acts dominantly in the FRT. These studies demonstrate that the establishment and maintenance of cell polarity through non-canonical Wnt signaling are required for FRT development. PMID:19363157

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

    OpenAIRE

    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, reflectin...

  17. Protein removal from waste brines generated during ham salting through acidification and centrifugation.

    Science.gov (United States)

    Gutiérrez-Martínez, Maria del Rosario; Muñoz-Guerrero, Hernán; Alcaína-Miranda, Maria Isabel; Barat, José Manuel

    2014-03-01

    The salting step in food processes implies the production of large quantities of waste brines, having high organic load, high conductivity, and other pollutants with high oxygen demand. Direct disposal of the residual brine implies salinization of soil and eutrophication of water. Since most of the organic load of the waste brines comes from proteins leaked from the salted product, precipitation of dissolved proteins by acidification and removal by centrifugation is an operation to be used in waste brine cleaning. The aim of this study is optimizing the conditions for carrying out the separation of proteins from waste brines generated in the pork ham salting operation, by studying the influence of pH, centrifugal force, and centrifugation time. Models for determining the removal of proteins depending on the pH, centrifugal force, and time were obtained. The results showed a high efficacy of the proposed treatment for removing proteins, suggesting that this method could be used for waste brine protein removal. The best pH value to be used in an industrial process seems to be 3, while the obtained results indicate that almost 90% of the proteins from the brine can be removed by acidification followed by centrifugation. A further protein removal from the brine should have to be achieved using filtrating techniques, which efficiency could be highly improved as a consequence of the previous treatment through acidification and centrifugation. Waste brines from meat salting have high organic load and electrical conductivity. Proteins can be removed from the waste brine by acidification and centrifugation. The total protein removal can be up to 90% of the initial content of the waste brine. Protein removal is highly dependent on pH, centrifugation rate, and time. © 2014 Institute of Food Technologists®

  18. Protein (multi-)location prediction: utilizing interdependencies via a generative model

    Science.gov (United States)

    Shatkay, Hagit

    2015-01-01

    Motivation: Proteins are responsible for a multitude of vital tasks in all living organisms. Given that a protein’s function and role are strongly related to its subcellular location, protein location prediction is an important research area. While proteins move from one location to another and can localize to multiple locations, most existing location prediction systems assign only a single location per protein. A few recent systems attempt to predict multiple locations for proteins, however, their performance leaves much room for improvement. Moreover, such systems do not capture dependencies among locations and usually consider locations as independent. We hypothesize that a multi-location predictor that captures location inter-dependencies can improve location predictions for proteins. Results: We introduce a probabilistic generative model for protein localization, and develop a system based on it—which we call MDLoc—that utilizes inter-dependencies among locations to predict multiple locations for proteins. The model captures location inter-dependencies using Bayesian networks and represents dependency between features and locations using a mixture model. We use iterative processes for learning model parameters and for estimating protein locations. We evaluate our classifier MDLoc, on a dataset of single- and multi-localized proteins derived from the DBMLoc dataset, which is the most comprehensive protein multi-localization dataset currently available. Our results, obtained by using MDLoc, significantly improve upon results obtained by an initial simpler classifier, as well as on results reported by other top systems. Availability and implementation: MDLoc is available at: http://www.eecis.udel.edu/∼compbio/mdloc. Contact: shatkay@udel.edu. PMID:26072505

  19. Wnt ligands signal in a cooperative manner to promote foregut organogenesis

    OpenAIRE

    Miller, Mayumi F.; Cohen, Ethan David; Baggs, Julie E.; Lu, Min Min; Hogenesch, John B.; Morrisey, Edward E.

    2012-01-01

    Endoderm-mesenchyme cross-talk is a central process in the development of foregut-derived organs. How signaling pathways integrate the activity of multiple ligands to guide organ development is poorly understood. We show that two Wnt ligands, Wnt2 and Wnt7b, cooperatively induce Wnt signaling without affecting the stabilization of the Wnt canonical effector β-catenin despite it being necessary for Wnt2–Wnt7b cooperativity. Wnt2–Wnt7b cooperation is specific for mesenchymal cell lineages and t...

  20. [Study on the influence of Wnt3a on osteogenetic differentiation ability of dental pulp stem cells induced by mineralizing medium].

    Science.gov (United States)

    Sun, Y Y; Yuan, M T; Shi, X; Liu, M Y; Hu, W P

    2016-10-09

    Objective: To investigate the effects of Wnt3a protein on proliferation and osteogenic differentiation of human dental pulp stem cells(DPSC). Methods: Intact human permanent teeth extracted for orthodontic reasons were collected and used as study models. The biological effects of Wnt3a on DPSC were investigated using methyl thiazolyl tetrazolium(MTT), alkaline phosphatase(ALP) activity assay, alizarin red S staining and realtime fluorescence quantitative PCR. Osteogenic-related gene expression of induced DPSC was examinedby using tests of bone sialoprotein(BSP), osteocalcin(OCN), collagen type Ⅰ (COL-Ⅰ) and Runt-related transcription factor 2(RUNX-2). Results: Wnt3a proteininduced an increase of cell growth and treatment of DPSC with Wnt3a induced a highest increase in cell growth at the concentration of 5 μg/L. 5 μg/L Wnt3a proteins combined with the osteogenic medium treatment caused up-regulated osteogenic differentiation, ALP activity and express of osteogenic-related genes of DPSC, and the ALP activity(0.47±0.04) was significantly stronger than the other groups(osteogenic medium: 0.39±0.05; 20 μg/L: 0.34±0.03; 50 μg/L: 0.27±0.07; 100 μg/L: 0.20±0.03). Conclusions: Exogenous Wnt3a protein treatment on DPSC could affect the proliferation and osteogenic differentiation.

  1. Wnt5a-mediated non-canonical Wnt signalling regulates human endothelial cell proliferation and migration

    International Nuclear Information System (INIS)

    Cheng Chingwen; Yeh Juching; Fan Taiping; Smith, Stephen K.; Charnock-Jones, D. Stephen

    2008-01-01

    Cell to cell interaction is one of the key processes effecting angiogenesis and endothelial cell function. Wnt signalling is mediated through cell-cell interaction and is involved in many developmental processes and cellular functions. In this study, we investigated the possible function of Wnt5a and the non-canonical Wnt pathway in human endothelial cells. We found that Wnt5a-mediated non-canonical Wnt signalling regulated endothelial cell proliferation. Blocking this pathway using antibody, siRNA or a down-stream inhibitor led to suppression of endothelial cell proliferation, migration, and monolayer wound closure. We also found that the mRNA level of Wnt5a is up-regulated when endothelial cells are treated with a cocktail of inflammatory cytokines. Our findings suggest non-canonical Wnt signalling plays a role in regulating endothelial cell growth and possibly in angiogenesis

  2. Epigenetic Activation of Wnt/β-Catenin Signaling in NAFLD-Associated Hepatocarcinogenesis

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    Yuan Tian

    2016-08-01

    Full Text Available Non-alcoholic fatty liver disease (NAFLD, characterized by fat accumulation in liver, is closely associated with central obesity, over-nutrition and other features of metabolic syndrome, which elevate the risk of developing hepatocellular carcinoma (HCC. The Wnt/β-catenin signaling pathway plays a significant role in the physiology and pathology of liver. Up to half of HCC patients have activation of Wnt/β-catenin signaling. However, the mutation frequencies of CTNNB1 (encoding β-catenin protein or other antagonists targeting Wnt/β-catenin signaling are low in HCC patients, suggesting that genetic mutations are not the major factor driving abnormal β-catenin activities in HCC. Emerging evidence has demonstrated that obesity-induced metabolic pathways can deregulate chromatin modifiers such as histone deacetylase 8 to trigger undesired global epigenetic changes, thereby modifying gene expression program which contributes to oncogenic signaling. This review focuses on the aberrant epigenetic activation of Wnt/β-catenin in the development of NAFLD-associated HCC. A deeper understanding of the molecular mechanisms underlying such deregulation may shed light on the identification of novel druggable epigenetic targets for the prevention and/or treatment of HCC in obese and diabetic patients.

  3. Wnt signalling antagonizes stress granule assembly through a Dishevelled-dependent mechanism

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    Pabitra K. Sahoo

    2012-02-01

    Cells often respond to diverse environmental stresses by inducing stress granules (SGs as an adaptive mechanism. SGs are generally assembled as a result of aggregation of mRNAs stalled in a translational pre-initiation complex, mediated by a set of RNA-binding proteins such as G3BP and TIA-1. SGs may serve as triage centres for storage, translation re-initiation or degradation of specific mRNAs. However, the mechanism involved in the modulation of their assembly/disassembly is unclear. Here we report that Wnt signalling negatively regulates SG assembly through Dishevelled (Dvl, a cytoplasmic Wnt effector. Overexpression of Dvl2, an isoform of Dvl, leads to impairment of SG assembly through a DEP domain dependent mechanism. Intriguingly, the Dvl2 mutant K446M, which corresponds to an analogous mutation in Drosophila Dishevelled DEP domain (dsh1 that results in defective PCP pathway, fails to antagonize SG assembly. Furthermore, we show that Dvl2 exerts the antagonistic effect on SG assembly through a mechanism involving Rac1-mediated inhibition of RhoA. Dvl2 interacts with G3BP, a downstream component of Ras signalling involved in SG assembly, and functional analysis suggests a model wherein the Dvl-Rac1-RhoA axis regulates G3BP's SG-nucleating activity. Collectively, these results define an antagonistic effect of Wnt signalling on SG assembly, and reveal a novel role for Wnt/Dvl pathway in the modulation of mRNA functions.

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

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    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.

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

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    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.

  6. 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.

  7. High basal Wnt signaling is further induced by PI3K/mTor inhibition but sensitive to cSRC inhibition in mammary carcinoma cell lines with HER2/3 overexpression

    International Nuclear Information System (INIS)

    Timmermans-Sprang, Elpetra P. M.; Gracanin, Ana; Mol, Jan A.

    2015-01-01

    Elevated basal, ligand-independent, Wnt signaling in some canine breast cancer cells is not caused by classical mutations in APC, β-Catenin or GSK3β but, at least partially, by enhanced LEF1 expression. We examined the expression and function of EGFR/HER-regulated pathways on the ligand-independent Wnt signaling. Twelve canine mammary tumor cell lines with previously reported differential basal Wnt activity were used. The expression levels of genes related to EGF-signaling were analyzed by cluster analysis. Cell lines with a combined overexpression of EGF-related genes and enhanced basal Wnt activity were treated with PI3K/mTor or cSRC inhibitors or transfected with a construct expressing wild-type PTEN. Subsequently, effects were measured on Wnt activity, cell proliferation, gene expression and protein level. High basal Wnt/LEF1 activity was associated with overexpression of HER2/3, ID1, ID2, RAC1 and HSP90 together with low to absent cMET and PTEN mRNA expression, suggesting a connection between Wnt- and HER-signaling pathways. Inhibition of the HER-regulated PI3K/mTor pathway using the dual PI3K/mTor inhibitor BEZ235 or the mTor inhibitor Everolimus® resulted in reduced cell proliferation. In the cell line with high basal Wnt activity, however, an unexpected further increased Wnt activity was found that could be greatly reduced after inhibition of the HER-regulated cSRC activity. Inhibition of the PI3K/mTor pathway was associated with enhanced expression of β-Catenin, Axin2, MUC1, cMET, EGFR and HER2 and a somewhat increased β-Catenin protein content, whereas cSRC inhibition was associated with slightly enhanced HER3 and SLUG mRNA expression. A high protein expression of HER3 was found only in a cell line with high basal Wnt activity. High basal Wnt activity in some mammary cancer cell lines is associated with overexpression of HER-receptor related genes and HER3 protein, and the absence of PTEN. Inhibition of the PI3K/mTor pathway further stimulated

  8. Generating a detailed protein profile of Fasciola hepatica during the chronic stage of infection in cattle.

    Science.gov (United States)

    Haçarız, Orçun; Baykal, Ahmet Tarık; Akgün, Mete; Kavak, Pınar; Sağıroğlu, Mahmut Şamil; Sayers, Gearóid Patrick

    2014-06-01

    Fasciola hepatica is a trematode helminth causing a damaging disease, fasciolosis, in ruminants and humans. Comprehensive proteomic studies broaden our knowledge of the parasite's protein profile, and provide new insights into the development of more effective strategies to deal with fasciolosis. The objective of this study was to generate a comprehensive profile of F. hepatica proteins expressed during the chronic stage of infection in cattle by building on previous efforts in this area. The approach included an improved sample preparation procedure for surface and internal layers of the parasite, the application of nano-UPLC-ESI-qTOF-MS (nano-ultra-performance LC and ESI quadrupole TOF MS) integrated with different acquisition methods and in silico database search against various protein databases and a transcript database including a new assembly of publically available EST. Of a total of 776 identified proteins, 206 and 332 were specific to the surface and internal layers of the parasite, respectively. Furthermore, 238 proteins were common to both layers, with comparative differences of 172 proteins detected. Specific proteins not previously identified in F. hepatica, but shown to be immunomodulatory or potential drug targets for other parasites, are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Enhanced protein loading on a planar Si(111)-H surface with second generation NTA

    Science.gov (United States)

    Liu, Xiang; Han, Huan-Mei; Liu, Hong-Bo; Xiao, Shou-jun

    2010-08-01

    A Si(111)-H surface was modified via a direct reaction between Si-H and 1-undecylenic acid (UA) under microwave irradiation to form molecular monolayers with terminal carboxyl groups. After esterifying carboxylic acid being esterified with N-hydroxysuccinimide (NHS), aminobutyl nitrilotriacetic acid (ANTA) was bound to the silicon surface through amidation (pH = 8.0) between its primary amino group and NHS-ester, producing nitrilotriacetic acid (NTA) anions. Then hexa-histidine tagged thioredoxin-urodilatin (his-tagged protein) and FITC-labeled hexa-histidine tagged thioredoxin-urodilatin (FITC-his-tagged protein) can be anchored after NTA was coordinated with Ni 2+. Furthermore, the NTA-terminated chip was acidified with 0.1 M HCl and subsequently esterified with NHS and then amidated with ANTA again to produce a second generation NTA. Thus the surface density of nitrilotriacetic acid anions was improved and resultantly that of anchored proteins was also enhanced through the iterative reactions. Both multiple transmission-reflection infrared spectroscopy (MTR-IR) and fluorescence scanning measurements demonstrated a proximate 1.63 times of anchored proteins on the second generation NTA/Ni 2+ as that on the first generation NTA/Ni 2+ monolayer.

  10. Calcitonin protects chondrocytes from lipopolysaccharide-induced apoptosis and inflammatory response through MAPK/Wnt/NF-κB pathways.

    Science.gov (United States)

    Zhang, Lai-Bo; Man, Zhen-Tao; Li, Wei; Zhang, Wei; Wang, Xian-Quan; Sun, Shui

    2017-07-01

    Calcitonin (CT) is an anti-absorbent, which has long been used for treatment of osteoporosis. However, little information is available about the effects of CT on osteoarthritis (OA). This study was mainly aimed to explore the effects of CT on the treatment of OA, as well as the underlying mechanisms. Chondrocytes were isolated from immature mice and then were incubated with lipopolysaccharide (LPS), CT, small interfering (si) RNA against bone morphogenetic protein (BMP)-2, and/or the inhibitors of MAPK/Wnt/NF-κB pathway. Thereafter, cell viability, apoptosis, nitric oxide (NO) and inflammatory factors productions, and expression levels of cartilage synthesis protein key factors, cartilage-derived morphogenetic protein (CDMP) 1, SRY (sex-determining region Y)-box 9 protein (SOX9), and MAPK/Wnt/NF-κB pathways key factors were determined. CT significantly reversed LPS-induced cell viability decrease, apoptosis increase, the inflammatory factors and NO secretion, the abnormally expression of cartilage synthesis proteins and the activation of MAPK/Wnt/NF-κB pathways (Ppathways statistically further increased the levels of CDMP1 and SOX9 (Ppathways, and could partially abolish CT-modulated the expression changes in CDMP1 and SOX9, and MAPK/Wnt/NF-κB pathways key factors (Ppathways. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. ProDaMa: an open source Python library to generate protein structure datasets

    Directory of Open Access Journals (Sweden)

    Manconi Andrea

    2009-10-01

    Full Text Available Abstract Background The huge difference between the number of known sequences and known tertiary structures has justified the use of automated methods for protein analysis. Although a general methodology to solve these problems has not been yet devised, researchers are engaged in developing more accurate techniques and algorithms whose training plays a relevant role in determining their performance. From this perspective, particular importance is given to the training data used in experiments, and researchers are often engaged in the generation of specialized datasets that meet their requirements. Findings To facilitate the task of generating specialized datasets we devised and implemented ProDaMa, an open source Python library than provides classes for retrieving, organizing, updating, analyzing, and filtering protein data. Conclusion ProDaMa has been used to generate specialized datasets useful for secondary structure prediction and to develop a collaborative web application aimed at generating and sharing protein structure datasets. The library, the related database, and the documentation are freely available at the URL http://iasc.diee.unica.it/prodama.

  12. Wnt signaling loss accelerates the appearance of neuropathological hallmarks of Alzheimer's disease in J20-APP transgenic and wild-type mice.

    Science.gov (United States)

    Tapia-Rojas, Cheril; Inestrosa, Nibaldo C

    2018-02-01

    Alzheimer's disease (AD) is a neurodegenerative pathology characterized by aggregates of amyloid-β (Aβ) and phosphorylated tau protein, synaptic dysfunction, and spatial memory impairment. The Wnt signaling pathway has several key functions in the adult brain and has been associated with AD, mainly as a neuroprotective factor against Aβ toxicity and tau phosphorylation. However, dysfunction of Wnt/β-catenin signaling might also play a role in the onset and development of the disease. J20 APPswInd transgenic (Tg) mouse model of AD was treated i.p. with various Wnt signaling inhibitors for 10 weeks during pre-symptomatic stages. Then, cognitive, biochemical and histochemical analyses were performed. Wnt signaling inhibitors induced severe changes in the hippocampus, including alterations in Wnt pathway components and loss of Wnt signaling function, severe cognitive deficits, increased tau phosphorylation and Aβ 1-42 peptide levels, decreased Aβ42/Aβ40 ratio and Aβ 1-42 concentration in the cerebral spinal fluid, and high levels of soluble Aβ species and synaptotoxic oligomers in the hippocampus, together with changes in the amount and size of senile plaques. More important, we also observed severe alterations in treated wild-type (WT) mice, including behavioral impairment, tau phosphorylation, increased Aβ 1-42 in the hippocampus, decreased Aβ 1-42 in the cerebral spinal fluid, and hippocampal dysfunction. Wnt inhibition accelerated the development of the pathology in a Tg AD mouse model and contributed to the development of Alzheimer's-like changes in WT mice. These results indicate that Wnt signaling plays important roles in the structure and function of the adult hippocampus and suggest that inhibition of the Wnt signaling pathway is an important factor in the pathogenesis of AD. Read the Editorial Highlight for this article on page 356. © 2017 International Society for Neurochemistry.

  13. Elevation of WNT5A expression in polyp formation in Lkb1+/- mice and Peutz-Jeghers syndrome.

    Science.gov (United States)

    Lai, Cecilia; Robinson, James; Clark, Sue; Stamp, Gordon; Poulsom, Richard; Silver, Andrew

    2011-04-01

    Peutz-Jeghers syndrome (PJS) is a rare, inherited disease caused by germline mutation of the LKB1 gene. Patients with PJS develop characteristic polyps in the digestive tract and carry an elevated risk of cancers in multiple organs, including the intestinal tract. While LKB1 is capable of phosphorylating AMPK and regulates the mTOR pathway, it is also known to be a multitasking protein that can influence other cellular processes, including cell polarity. We hypothesized that there may be other biological pathways directly or indirectly affected by the loss of LKB1 in PJS and aimed to investigate this possibility through transcriptional profiling of polyps harvested from an Lkb1(+/-) mouse model of PJS and from PJS patients. We identified alterations in the mRNA level of a wide range of genes, including some that are involved in Wnt signalling (Wnt5a, Wif1, Dixdc1, Wnt11, Ccnd1, and Ccnd2), although we did not observe nuclear localization of β-catenin in over 93 human PJS intestinal polyps or in 24 gastric polyps from Lkb1(+/-) mice. Among these genes, WNT5A, a non-canonical and non-transforming Wnt, is consistently up-regulated in both Lkb1(+/-) mice and human PJS polyps at a high level. We performed in situ hybridization to further define the spatial expression pattern of WNT5A and observed a strong signal in the stroma of mouse and human polyps compared to no or very low expression in the mucosa. Our findings indicate that WNT5A plays an important role in PJS polyposis. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  14. Interactions between TGF-β1, canonical WNT/β-catenin pathway and PPAR γ in radiation-induced fibrosis.

    Science.gov (United States)

    Vallée, Alexandre; Lecarpentier, Yves; Guillevin, Rémy; Vallée, Jean-Noël

    2017-10-27

    Radiation therapy induces DNA damage and inflammation leading to fibrosis. Fibrosis can occur 4 to 12 months after radiation therapy. This process worsens with time and years. Radiation-induced fibrosis is characterized by fibroblasts proliferation, myofibroblast differentiation, and synthesis of collagen, proteoglycans and extracellular matrix. Myofibroblasts are non-muscle cells that can contract and relax. Myofibroblasts evolve towards irreversible retraction during fibrosis process. In this review, we discussed the interplays between transforming growth factor-β1 (TGF-β1), canonical WNT/β-catenin pathway and peroxisome proliferator-activated receptor gamma (PPAR γ) in regulating the molecular mechanisms underlying the radiation-induced fibrosis, and the potential role of PPAR γ agonists. Overexpression of TGF-β and canonical WNT/β-catenin pathway stimulate fibroblasts accumulation and myofibroblast differentiation whereas PPAR γ expression decreases due to the opposite interplay of canonical WNT/β-catenin pathway. Both TGF-β1 and canonical WNT/β-catenin pathway stimulate each other through the Smad pathway and non-Smad pathways such as phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K/Akt) signaling. WNT/β-catenin pathway and PPAR γ interact in an opposite manner. PPAR γ agonists decrease β-catenin levels through activation of inhibitors of the WNT pathway such as Smad7, glycogen synthase kinase-3 (GSK-3 β) and dickkopf-related protein 1 (DKK1). PPAR γ agonists also stimulate phosphatase and tensin homolog (PTEN) expression, which decreases both TGF-β1 and PI3K/Akt pathways. PPAR γ agonists by activating Smad7 decrease Smads pathway and then TGF-β signaling leading to decrease radiation-induced fibrosis. TGF-β1 and canonical WNT/β-catenin pathway promote radiation-induced fibrosis whereas PPAR γ agonists can prevent radiation-induced fibrosis.

  15. Dibenzocyclooctadiene lignans, gomisins J and N inhibit the Wnt/β-catenin signaling pathway in HCT116 cells

    International Nuclear Information System (INIS)

    Kang, Kyungsu; Lee, Kyung-Mi; Yoo, Ji-Hye; Lee, Hee Ju; Kim, Chul Young; Nho, Chu Won

    2012-01-01

    Graphical abstract: Schematic diagram of the possible molecular mechanism underlying the inhibition of the Wnt/β-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: ► Gomisins J and N inhibited Wnt/β-catenin signaling pathway in HCT116 cells. ► Gomisins J and N disrupted the binding of β-catenin to specific DNA sequences, TBE. ► Gomisins J and N inhibited the HCT116 cell proliferation through G0/G1 phase arrest. ► Gomisins J and N inhibited the expression of Cyc D1, a Wnt/β-catenin target gene. -- Abstract: Here, we report that gomisin J and gomisin N, dibenzocyclooctadiene type lignans isolated from Schisandra chinensis, inhibit Wnt/β-catenin signaling in HCT116 cells. Gomisins J and N appear to inhibit Wnt/β-catenin signaling by disrupting the interaction between β-catenin and its specific target DNA sequences (TCF binding elements, TBE) rather than by altering the expression of the β-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/β-catenin signaling pathway, as well as Cdk2, Cdk4, and E2F-1. Therefore, gomisins J and N, the novel Wnt/β-catenin inhibitors discovered in this study, may serve as potential agents for the prevention and treatment of human colorectal cancers.

  16. Structure-function analysis of the C-clamp of TCF/Pangolin in Wnt/ß-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Aditi J Ravindranath

    Full Text Available The evolutionarily conserved Wnt/ß-catenin (Wnt/ß-cat pathway plays an important role in animal development in metazoans. Many Wnt targets are regulated by members of the TCF/LEF1 (TCF family of transcription factors. All TCFs contain a High Mobility Group (HMG domain that bind specific DNA sequences. Invertebrate TCFs and some vertebrate TCF isoforms also contain another domain, called the C-clamp, which allows TCFs to recognize an additional DNA motif known as the Helper site. While the C-clamp has been shown to be important for regulating several Wnt reporter genes in cell culture, its physiological role in regulating Wnt targets is less clear. In addition, little is known about this domain, except that two of the four conserved cysteines are functionally important. Here, we carried out a systematic mutagenesis and functional analysis of the C-clamp from the Drosophila TCF/Pangolin (TCF/Pan protein. We found that the C-clamp is a zinc-binding domain that is sufficient for binding to the Helper site. In addition to this DNA-binding activity, the C-clamp also inhibits the HMG domain from binding its cognate DNA site. Point mutations were identified that specifically affected DNA-binding or reduced the inhibitory effect. These mutants were characterized in TCF/Pan rescue assays. The specific DNA-binding activity of the C-clamp was essential for TCF/Pan function in cell culture and in patterning the embryonic epidermis of Drosophila, demonstrating the importance of this C-clamp activity in regulating Wnt target gene expression. In contrast, the inhibitory mutation had a subtle effect in cell culture and no effect on TCF/Pan activity in embryos. These results provide important information about the functional domains of the C-clamp, and highlight its importance for Wnt/ß-cat signaling in Drosophila.

  17. 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.

  18. A Comprehensive Overview of Skeletal Phenotypes Associated with Alterations in Wnt/β-catenin Signaling in Humans and Mice.

    Science.gov (United States)

    Maupin, Kevin A; Droscha, Casey J; Williams, Bart O

    2013-03-01

    The Wnt signaling pathway plays key roles in differentiation and development and alterations in this signaling pathway are causally associated with numerous human diseases. While several laboratories were examining roles for Wnt signaling in skeletal development during the 1990s, interest in the pathway rose exponentially when three key papers were published in 2001-2002. One report found that loss of the Wnt co-receptor, Low-density lipoprotein related protein-5 (LRP5), was the underlying genetic cause of the syndrome Osteoporosis pseudoglioma (OPPG). OPPG is characterized by early-onset osteoporosis causing increased susceptibility to debilitating fractures. Shortly thereafter, two groups reported that individuals carrying a specific point mutation in LRP5 (G171V) develop high-bone mass. Subsequent to this, the causative mechanisms for these observations heightened the need to understand the mechanisms by which Wnt signaling controlled bone development and homeostasis and encouraged significant investment from biotechnology and pharmaceutical companies to develop methods to activate Wnt signaling to increase bone mass to treat osteoporosis and other bone disease. In this review, we will briefly summarize the cellular mechanisms underlying Wnt signaling and discuss the observations related to OPPG and the high-bone mass disorders that heightened the appreciation of the role of Wnt signaling in normal bone development and homeostasis. We will then present a comprehensive overview of the core components of the pathway with an emphasis on the phenotypes associated with mice carrying genetically engineered mutations in these genes and clinical observations that further link alterations in the pathway to changes in human bone.

  19. Structure-Function Analysis of the C-clamp of TCF/Pangolin in Wnt/ß-catenin Signaling

    Science.gov (United States)

    Ravindranath, Aditi; Cadigan, Ken M.

    2014-01-01

    The evolutionarily conserved Wnt/ß-catenin (Wnt/ß-cat) pathway plays an important role in animal development in metazoans. Many Wnt targets are regulated by members of the TCF/LEF1 (TCF) family of transcription factors. All TCFs contain a High Mobility Group (HMG) domain that bind specific DNA sequences. Invertebrate TCFs and some vertebrate TCF isoforms also contain another domain, called the C-clamp, which allows TCFs to recognize an additional DNA motif known as the Helper site. While the C-clamp has been shown to be important for regulating several Wnt reporter genes in cell culture, its physiological role in regulating Wnt targets is less clear. In addition, little is known about this domain, except that two of the four conserved cysteines are functionally important. Here, we carried out a systematic mutagenesis and functional analysis of the C-clamp from the Drosophila TCF/Pangolin (TCF/Pan) protein. We found that the C-clamp is a zinc-binding domain that is sufficient for binding to the Helper site. In addition to this DNA-binding activity, the C-clamp also inhibits the HMG domain from binding its cognate DNA site. Point mutations were identified that specifically affected DNA-binding or reduced the inhibitory effect. These mutants were characterized in TCF/Pan rescue assays. The specific DNA-binding activity of the C-clamp was essential for TCF/Pan function in cell culture and in patterning the embryonic epidermis of Drosophila, demonstrating the importance of this C-clamp activity in regulating Wnt target gene expression. In contrast, the inhibitory mutation had a subtle effect in cell culture and no effect on TCF/Pan activity in embryos. These results provide important information about the functional domains of the C-clamp, and highlight its importance for Wnt/ß-cat signaling in Drosophila. PMID:24465946

  20. Towards protein-crystal centering using second-harmonic generation (SHG) microscopy

    International Nuclear Information System (INIS)

    Kissick, David J.; Dettmar, Christopher M.; Becker, Michael; Mulichak, Anne M.; Cherezov, Vadim; Ginell, Stephan L.; Battaile, Kevin P.; Keefe, Lisa J.; Fischetti, Robert F.; Simpson, Garth J.

    2013-01-01

    The potential of second-harmonic generation (SHG) microscopy for automated crystal centering to guide synchrotron X-ray diffraction of protein crystals has been explored. The potential of second-harmonic generation (SHG) microscopy for automated crystal centering to guide synchrotron X-ray diffraction of protein crystals was explored. These studies included (i) comparison of microcrystal positions in cryoloops as determined by SHG imaging and by X-ray diffraction rastering and (ii) X-ray structure determinations of selected proteins to investigate the potential for laser-induced damage from SHG imaging. In studies using β 2 adrenergic receptor membrane-protein crystals prepared in lipidic mesophase, the crystal locations identified by SHG images obtained in transmission mode were found to correlate well with the crystal locations identified by raster scanning using an X-ray minibeam. SHG imaging was found to provide about 2 µm spatial resolution and shorter image-acquisition times. The general insensitivity of SHG images to optical scatter enabled the reliable identification of microcrystals within opaque cryocooled lipidic mesophases that were not identified by conventional bright-field imaging. The potential impact of extended exposure of protein crystals to five times a typical imaging dose from an ultrafast laser source was also assessed. Measurements of myoglobin and thaumatin crystals resulted in no statistically significant differences between structures obtained from diffraction data acquired from exposed and unexposed regions of single crystals. Practical constraints for integrating SHG imaging into an active beamline for routine automated crystal centering are discussed

  1. Methods for generating protein molecular ions in ToF-SIMS.

    Science.gov (United States)

    McArthur, Sally L; Vendettuoli, Marie C; Ratner, Buddy D; Castner, David G

    2004-04-27

    One of the greatest challenges in mass spectrometry lies in the generation and detection of molecular ions that can be used to directly identify the protein from the molecular weight of the molecular ion. Typically, proteins are large (MW > 1000), nonvolatile, and/or thermally labile, but the vaporization process produced by many mass spectrometry techniques including time-of-flight secondary ion mass spectrometry (ToF-SIMS) is inherently limited to generating ions from smaller compounds or fragments of the parent molecule, making the identification of proteins complex. The application of specific molecules to aid in the generation of high molecular weight ions in ToF-SIMS has been recognized for some time. In this study we have developed a matrix-SAM substrate preparation technique based on the self-assembly of a matrix-like molecule, mercaptonicotinic acid (MNA), on gold. We then compare this substrate with two existing ToF-SIMS sample preparation techniques, cationized alkane thiol and matrix-enhanced SIMS (MESIMS). The results of this study illustrate that while there is a range of methods that can be used to improve the molecular ion yield of proteins in ToF-SIMS, their efficacy and reproducibility vary considerably and crucially are linked to the sample preparation and/or protein application methods used. Critically, the MNA modified substrate was able to simultaneously induce molecular ions for each protein present in a multicomponent solution, suggesting that this sample preparation technique may have future application in proteomics and DNA analysis.

  2. [Effect of total glucosides of paeony on Wnt/β-catenin signal transduction pathway expression in kidney of diabetic rats].

    Science.gov (United States)

    Chang, Bao-Chao; Chen, Wei-Dong; Zhang, Yan; Yang, Ping; Liu, Lei; Wang, Jing

    2014-10-01

    The study is to explore the effect of total glucosides of paeony (TGP)on Wnt/β-catenin signal transduction pathway expression in kidney of diabetic rats, and discuss the protection of TGP in diabetic nephropathy and possible mechanism. Ninety male SD rats of 8 weeks age were randomly divided into normal control group (n = 10) and model group (n = 80). Rats of the normal control group were fed with regular diet, while rats of the model group were fed with high-fat high-sugar diet and 4 weeks later were given an intraperitoneal injection of 35 mg x kg(-1) streptozotocin (STZ). The successfully induced type 2 diabetic rat models were then randomly divided into DM group, three TGP (50, 100, 200 mg x kg(-1) x d(-1)) treatment group and tripterygium wilfordii glycosides (8 mg x kg(-1) x d(-1)) control group. Rats of DM group and each treatment group were given high-fat high-sugar diet. At week 14, the levels of blood sugar, 24 hour urine protein, serum creatinine and blood urea nitrogen were tested. The rats were then sacrificed. Renal pathological changes were examined. Renal tissue Wnt-1 and β-catenin expressions were detected by immunohistochemical assay. Wnt-1 mRNA and β-catenin mRNA expression was semi-quantified by RT-PCR. Wnt-1 protein and β-catenin protein expression was semi-quantified by Western blot. The Result show that Wnt-1 and β-catenin expression increased in kidney of high-fat high-sugar induced type 2 diabetic rats. Compared with diabetic group, the level of serum creatinine, blood urea nitrogen, 24 h urine protein, mean glomerular area and mean glomerular volume were decreased, renal histopathology were improved, expression of Wnt-1 and β-catenin mRNA and protein was reduced in TGP group. Tripterygium wilfordii glycosides had the similar effect. In conclusion, these results showed that Wnt/β-catenin abnormal activation in kidney of type 2 diabetic rats, TGP can improve kidney damage in diabetic rats and delay the development of diabetic

  3. Modulation of Wnt Signaling Enhances Inner Ear Organoid Development in 3D Culture.

    Directory of Open Access Journals (Sweden)

    Rachel E DeJonge

    Full Text Available Stem cell-derived inner ear sensory epithelia are a promising source of tissues for treating patients with hearing loss and dizziness. We recently demonstrated how to generate inner ear sensory epithelia, designated as inner ear organoids, from mouse embryonic stem cells (ESCs in a self-organizing 3D culture. Here we improve the efficiency of this culture system by elucidating how Wnt signaling activity can drive the induction of otic tissue. We found that a carefully timed treatment with the potent Wnt agonist CHIR99021 promotes induction of otic vesicles-a process that was previously self-organized by unknown mechanisms. The resulting otic-like vesicles have a larger lumen size and contain a greater number of Pax8/Pax2-positive otic progenitor cells than organoids derived without the Wnt agonist. Additionally, these otic-like vesicles give rise to large inner ear organoids with hair cells whose morphological, biochemical and functional properties are indistinguishable from those of vestibular hair cells in the postnatal mouse inner ear. We conclude that Wnt signaling plays a similar role during inner ear organoid formation as it does during inner ear development in the embryo.

  4. Redifferentiation of adult human β cells expanded in vitro by inhibition of the WNT pathway.

    Directory of Open Access Journals (Sweden)

    Ayelet Lenz

    Full Text Available In vitro expansion of adult human islet β cells is an attractive solution for the shortage of tissue for cell replacement therapy of type 1 diabetes. Using a lineage tracing approach we have demonstrated that β-cell-derived (BCD cells rapidly dedifferentiate in culture and can proliferate for up to 16 population doublings. Dedifferentiation is associated with changes resembling epithelial-mesenchymal transition (EMT. The WNT pathway has been shown to induce EMT and plays key roles in regulating replication and differentiation in many cell types. Here we show that BCD cell dedifferentiation is associated with β-catenin translocation into the nucleus and activation of the WNT pathway. Inhibition of β-catenin expression in expanded BCD cells using short hairpin RNA resulted in growth arrest, mesenchymal-epithelial transition, and redifferentiation, as judged by activation of β-cell gene expression. Furthermore, inhibition of β-catenin expression synergized with redifferentiation induced by a combination of soluble factors, as judged by an increase in the number of C-peptide-positive cells. Simultaneous inhibition of the WNT and NOTCH pathways also resulted in a synergistic effect on redifferentiation. These findings, which were reproducible in cells derived from multiple human donors, suggest that inhibition of the WNT pathway may contribute to a therapeutically applicable way for generation of functional insulin-producing cells following ex-vivo expansion.

  5. A Comparative Perspective on Wnt/β-Catenin Signalling in Cell Fate Determination.

    Science.gov (United States)

    Garcin, Clare L; Habib, Shukry J

    The Wnt/β-catenin pathway is an ancient and highly conserved signalling pathway that plays fundamental roles in the regulation of embryonic development and adult homeostasis. This pathway has been implicated in numerous cellular processes, including cell proliferation, differentiation, migration, morphological changes and apoptosis. In this chapter, we aim to illustrate with specific examples the involvement of Wnt/β-catenin signalling in cell fate determination. We discuss the roles of the Wnt/β-catenin pathway in specifying cell fate throughout evolution, how its function in patterning during development is often reactivated during regeneration and how perturbation of this pathway has negative consequences for the control of cell fate.The origin of all life was a single cell that had the capacity to respond to cues from the environment. With evolution, multicellular organisms emerged, and as a result, subsets of cells arose to form tissues able to respond to specific instructive signals and perform specialised functions. This complexity and specialisation required two types of messages to direct cell fate: intra- and intercellular. A fundamental question in developmental biology is to understand the underlying mechanisms of cell fate choice. Amongst the numerous external cues involved in the generation of cellular diversity, a prominent pathway is the Wnt signalling pathway in all its forms.

  6. The Wnt Transcriptional Switch: TLE Removal or Inactivation?

    Science.gov (United States)

    Ramakrishnan, Aravinda-Bharathi; Sinha, Abhishek; Fan, Vinson B; Cadigan, Ken M

    2018-02-01

    Many targets of the Wnt/β-catenin signaling pathway are regulated by TCF transcription factors, which play important roles in animal development, stem cell biology, and oncogenesis. TCFs can regulate Wnt targets through a "transcriptional switch," repressing gene expression in unstimulated cells and promoting transcription upon Wnt signaling. However, it is not clear whether this switch mechanism is a general feature of Wnt gene regulation or limited to a subset of Wnt targets. Co-repressors of the TLE family are known to contribute to the repression of Wnt targets in the absence of signaling, but how they are inactivated or displaced by Wnt signaling is poorly understood. In this mini-review, we discuss several recent reports that address the prevalence and molecular mechanisms of the Wnt transcription switch, including the finding of Wnt-dependent ubiquitination/inactivation of TLEs. Together, these findings highlight the growing complexity of the regulation of gene expression by the Wnt pathway. © 2017 WILEY Periodicals, Inc.

  7. Canonical Wnt signaling in the oligodendroglial lineage--puzzles remain.

    Science.gov (United States)

    Guo, Fuzheng; Lang, Jordan; Sohn, Jiho; Hammond, Elizabeth; Chang, Marcello; Pleasure, David

    2015-10-01

    The straightforward concept that accentuated Wnt signaling via the Wnt-receptor-β-catenin-TCF/LEF cascade (also termed canonical Wnt signaling or Wnt/β-catenin signaling) delays or blocks oligodendrocyte differentiation is very appealing. According to this concept, canonical Wnt signaling is responsible for remyelination failure in multiple sclerosis and for persistent hypomyelination in periventricular leukomalacia. This has given rise to the hope that pharmacologically inhibiting this signaling will be of therapeutic potential in these disabling neurological disorders. But current studies suggest that Wnt/β-catenin signaling plays distinct roles in oligodendrogenesis, oligodendrocyte differentiation, and myelination in a context-dependent manner (central nervous system regions, developmental stages), and that Wnt/β-catenin signaling interplays with, and is subjected to regulation by, other central nervous system factors and signaling pathways. On this basis, we propose the more nuanced concept that endogenous Wnt/β-catenin activity is delicately and temporally regulated to ensure the seamless development of oligodendroglial lineage cells in different contexts. In this review, we discuss the role Wnt/β-catenin signaling in oligodendrocyte development, focusing on the interpretation of disparate results, and highlighting areas where important questions remain to be answered about oligodendroglial lineage Wnt/β-catenin signaling. © 2015 Wiley Periodicals, Inc.

  8. Wnt-3a is critical for caudal embryonic development

    Energy Technology Data Exchange (ETDEWEB)

    Camper, S.A.; Greco, T.L.; Newhouse, M.M. [Univ. of Michigan Medical School, Ann Arbor, MI (United States)] [and others

    1994-09-01

    Skeletal and neural tube defects represent an important class of birth defects. The majority of mouse mutants with neural tube defects also have malformations of the tail. Vestigial tail (vt) is an autosomal recessive mouse mutation characterized by reduction or absence of the tail, vertebral abnormalities, and reduced fertility. The phenotype has been described as the result of failure of cell migration through the primitive streak, causing abnormalities in the development of the neural tube and a reduction in the ventral ectodermal ridge. Wnt3a is an excellent candidate gene for vt because Wnt3a is expressed in the primitive streak and in the embryonic mesoderm, and it is thought to be involved in cell-to-cell communication and formation of the dorsal-ventral axis in the CNS. A lack of Wnt3a might be expected to result in overdorsalization of the neural tube and reduction of the ventral ectodermal ridge characteristic of vt/vt embryos. In a high resolution backcross segregating vt, we observed no recombination between vt and Wnt3a in 363 individuals analyzed. In vt/vt mice, Southern blot analysis revealed no abnormalities in the Wnt3a gene, and the Wnt3a cDNA sequence does not encode any amino acid changes. Whole mount in situ hybridization analysis demonstrated that Wnt3a expression is severely reduced in the developing tailbud of day 9.5 vt/vt embryos, suggestive of a lesion in the regulation on Wnt3a expression. An alleleism test, carried out by mating vt/vt males with Wnt3a +/Wnt3a- females, demonstrated that vt and Wnt3a are noncomplementing alleles. All of the compound heterozygotes exhibited severe tail defects, including occasional examples of hind limb parlaysis and spina bifida. The vertebral defects are intermediate between those of vt and Wnt3a homozygotes, suggesting that the concentration of Wnt3a correlates with the severity of the defect.

  9. SNaPe: a versatile method to generate multiplexed protein fusions using synthetic linker peptides for in vitro applications.

    Science.gov (United States)

    Ulrich, Veronika; Cryle, Max J

    2017-01-01

    Understanding the structure and function of protein complexes and multi-domain proteins is highly important in biology, although the in vitro characterization of these systems is often complicated by their size or the transient nature of protein/protein interactions. To assist in the characterization of such protein complexes, we have developed a modular approach to fusion protein generation that relies upon Sortase-mediated and Native chemical ligation using synthetic Peptide linkers (SNaPe) to link two separately expressed proteins. In this approach, we utilize two separate linking steps - sortase-mediated and native chemical ligation - together with a library of peptide linkers to generate libraries of fusion proteins. We have demonstrated the viability of SNaPe to generate libraries from fusion protein constructs taken from the biosynthetic enzymes responsible for late stage aglycone assembly during glycopeptide antibiotic biosynthesis. Crucially, SNaPe was able to generate fusion proteins that are inaccessible via direct expression of the fusion construct itself. This highlights the advantages of SNaPe to not only access fusion proteins that have been previously unavailable for biochemical and structural characterization but also to do so in a manner that enables the linker itself to be controlled as an experimental parameter of fusion protein generation. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  10. A cDNA Immunization Strategy to Generate Nanobodies against Membrane Proteins in Native Conformation

    Directory of Open Access Journals (Sweden)

    Thomas Eden

    2018-01-01

    Full Text Available Nanobodies (Nbs are soluble, versatile, single-domain binding modules derived from the VHH variable domain of heavy-chain antibodies naturally occurring in camelids. Nbs hold huge promise as novel therapeutic biologics. Membrane proteins are among the most interesting targets for therapeutic Nbs because they are accessible to systemically injected biologics. In order to be effective, therapeutic Nbs must recognize their target membrane protein in native conformation. However, raising Nbs against membrane proteins in native conformation can pose a formidable challenge since membrane proteins typically contain one or more hydrophobic transmembrane regions and, therefore, are difficult to purify in native conformation. Here, we describe a highly efficient genetic immunization strategy that circumvents these difficulties by driving expression of the target membrane protein in native conformation by cells of the immunized camelid. The strategy encompasses ballistic transfection of skin cells with cDNA expression plasmids encoding one or more orthologs of the membrane protein of interest and, optionally, other costimulatory proteins. The plasmid is coated onto 1 µm gold particles that are then injected into the shaved and depilated skin of the camelid. A gene gun delivers a helium pulse that accelerates the DNA-coated particles to a velocity sufficient to penetrate through multiple layers of cells in the skin. This results in the exposure of the extracellular domains of the membrane protein on the cell surface of transfected cells. Repeated immunization drives somatic hypermutation and affinity maturation of target-specific heavy-chain antibodies. The VHH/Nb coding region is PCR-amplified from B cells obtained from peripheral blood or a lymph node biopsy. Specific Nbs are selected by phage display or by screening of Nb-based heavy-chain antibodies expressed as secretory proteins in transfected HEK cells. Using this strategy, we have successfully

  11. A cDNA Immunization Strategy to Generate Nanobodies against Membrane Proteins in Native Conformation

    Science.gov (United States)

    Eden, Thomas; Menzel, Stephan; Wesolowski, Janusz; Bergmann, Philine; Nissen, Marion; Dubberke, Gudrun; Seyfried, Fabienne; Albrecht, Birte; Haag, Friedrich; Koch-Nolte, Friedrich

    2018-01-01

    Nanobodies (Nbs) are soluble, versatile, single-domain binding modules derived from the VHH variable domain of heavy-chain antibodies naturally occurring in camelids. Nbs hold huge promise as novel therapeutic biologics. Membrane proteins are among the most interesting targets for therapeutic Nbs because they are accessible to systemically injected biologics. In order to be effective, therapeutic Nbs must recognize their target membrane protein in native conformation. However, raising Nbs against membrane proteins in native conformation can pose a formidable challenge since membrane proteins typically contain one or more hydrophobic transmembrane regions and, therefore, are difficult to purify in native conformation. Here, we describe a highly efficient genetic immunization strategy that circumvents these difficulties by driving expression of the target membrane protein in native conformation by cells of the immunized camelid. The strategy encompasses ballistic transfection of skin cells with cDNA expression plasmids encoding one or more orthologs of the membrane protein of interest and, optionally, other costimulatory proteins. The plasmid is coated onto 1 µm gold particles that are then injected into the shaved and depilated skin of the camelid. A gene gun delivers a helium pulse that accelerates the DNA-coated particles to a velocity sufficient to penetrate through multiple layers of cells in the skin. This results in the exposure of the extracellular domains of the membrane protein on the cell surface of transfected cells. Repeated immunization drives somatic hypermutation and affinity maturation of target-specific heavy-chain antibodies. The VHH/Nb coding region is PCR-amplified from B cells obtained from peripheral blood or a lymph node biopsy. Specific Nbs are selected by phage display or by screening of Nb-based heavy-chain antibodies expressed as secretory proteins in transfected HEK cells. Using this strategy, we have successfully generated agonistic

  12. Global regulator SATB1 recruits beta-catenin and regulates T(H2 differentiation in Wnt-dependent manner.

    Directory of Open Access Journals (Sweden)

    Dimple Notani

    2010-01-01

    Full Text Available In vertebrates, the conserved Wnt signalling cascade promotes the stabilization and nuclear accumulation of beta-catenin, which then associates with the lymphoid enhancer factor/T cell factor proteins (LEF/TCFs to activate target genes. Wnt/beta -catenin signalling is essential for T cell development and differentiation. Here we show that special AT-rich binding protein 1 (SATB1, the T lineage-enriched chromatin organizer and global regulator, interacts with beta-catenin and recruits it to SATB1's genomic binding sites. Gene expression profiling revealed that the genes repressed by SATB1 are upregulated upon Wnt signalling. Competition between SATB1 and TCF affects the transcription of TCF-regulated genes upon beta-catenin signalling. GATA-3 is a T helper type 2 (T(H2 specific transcription factor that regulates production of T(H2 cytokines and functions as T(H2 lineage determinant. SATB1 positively regulated GATA-3 and siRNA-mediated knockdown of SATB1 downregulated GATA-3 expression in differentiating human CD4(+ T cells, suggesting that SATB1 influences T(H2 lineage commitment by reprogramming gene expression. In the presence of Dickkopf 1 (Dkk1, an inhibitor of Wnt signalling, GATA-3 is downregulated and the expression of signature T(H2 cytokines such as IL-4, IL-10, and IL-13 is reduced, indicating that Wnt signalling is essential for T(H2 differentiation. Knockdown of beta-catenin also produced similar results, confirming the role of Wnt/beta-catenin signalling in T(H2 differentiation. Furthermore, chromatin immunoprecipitation analysis revealed that SATB1 recruits beta-catenin and p300 acetyltransferase on GATA-3 promoter in differentiating T(H2 cells in a Wnt-dependent manner. SATB1 coordinates T(H2 lineage commitment by reprogramming gene expression. The SATB1:beta-catenin complex activates a number of SATB1 regulated genes, and hence this study has potential to find novel Wnt responsive genes. These results demonstrate that SATB1

  13. Automatic generation of 3D motifs for classification of protein binding sites

    Directory of Open Access Journals (Sweden)

    Herzyk Pawel

    2007-08-01

    Full Text Available Abstract Background Since many of the new protein structures delivered by high-throughput processes do not have any known function, there is a need for structure-based prediction of protein function. Protein 3D structures can be clustered according to their fold or secondary structures to produce classes of some functional significance. A recent alternative has been to detect specific 3D motifs which are often associated to active sites. Unfortunately, there are very few known 3D motifs, which are usually the result of a manual process, compared to the number of sequential motifs already known. In this paper, we report a method to automatically generate 3D motifs of protein structure binding sites based on consensus atom positions and evaluate it on a set of adenine based ligands. Results Our new approach was validated by generating automatically 3D patterns for the main adenine based ligands, i.e. AMP, ADP and ATP. Out of the 18 detected patterns, only one, the ADP4 pattern, is not associated with well defined structural patterns. Moreover, most of the patterns could be classified as binding site 3D motifs. Literature research revealed that the ADP4 pattern actually corresponds to structural features which show complex evolutionary links between ligases and transferases. Therefore, all of the generated patterns prove to be meaningful. Each pattern was used to query all PDB proteins which bind either purine based or guanine based ligands, in order to evaluate the classification and annotation properties of the pattern. Overall, our 3D patterns matched 31% of proteins with adenine based ligands and 95.5% of them were classified correctly. Conclusion A new metric has been introduced allowing the classification of proteins according to the similarity of atomic environment of binding sites, and a methodology has been developed to automatically produce 3D patterns from that classification. A study of proteins binding adenine based ligands showed that

  14. The negative impact of Wnt signaling on megakaryocyte and primitive erythroid progenitors derived from human embryonic stem cells

    Directory of Open Access Journals (Sweden)

    Prasuna Paluru

    2014-03-01

    Full Text Available The Wnt gene family consists of structurally related genes encoding secreted signaling molecules that have been implicated in many developmental processes, including regulation of cell fate and patterning during embryogenesis. Previously, we found that Wnt signaling is required for primitive or yolk sac-derived-erythropoiesis using the murine embryonic stem cell (ESC system. Here, we examine the effect of Wnt signaling on the formation of early hematopoietic progenitors derived from human ESCs. The first hematopoietic progenitor cells in the human ESC system express the pan-hematopoietic marker CD41 and the erythrocyte marker, glycophorin A or CD235. We have developed a novel serum-free, feeder-free, adherent differentiation system that can efficiently generate large numbers of CD41 + CD235+ cells. We demonstrate that this cell population contains progenitors not just for primitive erythroid and megakaryocyte cells but for the myeloid lineage as well and term this population the primitive common myeloid progenitor (CMP. Treatment of mesoderm-specified cells with Wnt3a led to a loss of hematopoietic colony-forming ability while the inhibition of canonical Wnt signaling with DKK1 led to an increase in the number of primitive CMPs. Canonical Wnt signaling also inhibits the expansion and/or survival of primitive erythrocytes and megakaryocytes, but not myeloid cells, derived from this progenitor population. These findings are in contrast to the role of Wnt signaling during mouse ESC differentiation and demonstrate the importance of the human ESC system in studying species-specific differences in development.

  15. The APEX Quantitative Proteomics Tool: Generating protein quantitation estimates from LC-MS/MS proteomics results

    Directory of Open Access Journals (Sweden)

    Saeed Alexander I

    2008-12-01

    Full Text Available Abstract Background Mass spectrometry (MS based label-free protein quantitation has mainly focused on analysis of ion peak heights and peptide spectral counts. Most analyses of tandem mass spectrometry (MS/MS data begin with an enzymatic digestion of a complex protein mixture to generate smaller peptides that can be separated and identified by an MS/MS instrument. Peptide spectral counting techniques attempt to quantify protein abundance by counting the number of detected tryptic peptides and their corresponding MS spectra. However, spectral counting is confounded by the fact that peptide physicochemical properties severely affect MS detection resulting in each peptide having a different detection probability. Lu et al. (2007 described a modified spectral counting technique, Absolute Protein Expression (APEX, which improves on basic spectral counting methods by including a correction factor for each protein (called Oi value that accounts for variable peptide detection by MS techniques. The technique uses machine learning classification to derive peptide detection probabilities that are used to predict the number of tryptic peptides expected to be detected for one molecule of a particular protein (Oi. This predicted spectral count is compared to the protein's observed MS total spectral count during APEX computation of protein abundances. Results The APEX Quantitative Proteomics Tool, introduced here, is a free open source Java application that supports the APEX protein quantitation technique. The APEX tool uses data from standard tandem mass spectrometry proteomics experiments and provides computational support for APEX protein abundance quantitation through a set of graphical user interfaces that partition thparameter controls for the various processing tasks. The tool also provides a Z-score analysis for identification of significant differential protein expression, a utility to assess APEX classifier performance via cross validation, and a

  16. Protein disulfide bond generation in Escherichia coli DsbB–DsbA

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Kenji, E-mail: inaba-k@bioreg.kyushu-u.ac.jp [Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582 (Japan)

    2008-05-01

    The crystal structure of the DsbB–DsbA–ubiquinone ternary complex has revealed a mechanism of protein disulfide bond generation in Escherichia coli. Protein disulfide bond formation is catalyzed by a series of Dsb enzymes present in the periplasm of Escherichia coli. The crystal structure of the DsbB–DsbA–ubiquinone ternary complex provided important insights into mechanisms of the de novo disulfide bond generation cooperated by DsbB and ubiquinone and of the disulfide bond shuttle from DsbB to DsbA. The structural basis for prevention of the crosstalk between the DsbA–DsbB oxidative and the DsbC–DsbD reductive pathways has also been proposed.

  17. Protein disulfide bond generation in Escherichia coli DsbB–DsbA

    International Nuclear Information System (INIS)

    Inaba, Kenji

    2008-01-01

    The crystal structure of the DsbB–DsbA–ubiquinone ternary complex has revealed a mechanism of protein disulfide bond generation in Escherichia coli. Protein disulfide bond formation is catalyzed by a series of Dsb enzymes present in the periplasm of Escherichia coli. The crystal structure of the DsbB–DsbA–ubiquinone ternary complex provided important insights into mechanisms of the de novo disulfide bond generation cooperated by DsbB and ubiquinone and of the disulfide bond shuttle from DsbB to DsbA. The structural basis for prevention of the crosstalk between the DsbA–DsbB oxidative and the DsbC–DsbD reductive pathways has also been proposed

  18. Wnt/β-catenin and sonic hedgehog pathways interact in the regulation of the development of the dorsal mesenchymal protrusion

    NARCIS (Netherlands)

    Briggs, Laura E.; Burns, Tara A.; Lockhart, Marie M.; Phelps, Aimee L.; van den Hoff, Maurice J. B.; Wessels, Andy

    2016-01-01

    The dorsal mesenchymal protrusion (DMP) is a second heart field (SHF) derived tissue involved in cardiac septation. Molecular mechanisms controlling SHF/DMP development include the Bone Morphogenetic Protein and Wnt/β-catenin signaling pathways. Reduced expression of components in these pathways

  19. PITX2 and non-canonical Wnt pathway interaction in metastatic prostate cancer.

    Science.gov (United States)

    Vela, I; Morrissey, C; Zhang, X; Chen, S; Corey, E; Strutton, G M; Nelson, C C; Nicol, D L; Clements, J A; Gardiner, E M

    2014-02-01

    The non-canonical Wnt pathway, a regulator of cellular motility and morphology, is increasingly implicated in cancer metastasis. In a quantitative PCR array analysis of 84 Wnt pathway associated genes, both non-canonical and canonical pathways were activated in primary and metastatic tumors relative to normal prostate. Expression of the Wnt target gene PITX2 in a prostate cancer (PCa) bone metastasis was strikingly elevated over normal prostate (over 2,000-fold) and primary prostate cancer (over 200-fold). The elevation of PITX2 protein was also evident on tissue microarrays, with strong PITX2 immunostaining in PCa skeletal and, to a lesser degree, soft tissue metastases. PITX2 is associated with cell migration during normal tissue morphogenesis. In our studies, overexpression of individual PITX2A/B/C isoforms stimulated PC-3 PCa cell motility, with the PITX2A isoform imparting a specific motility advantage in the presence of non-canonical Wnt5a stimulation. Furthermore, PITX2 specific shRNA inhibited PC-3 cell migration toward bone cell derived chemoattractant. These experimental results support a pivotal role of PITX2A and non-canonical Wnt signaling in enhancement of PCa cell motility, suggest PITX2 involvement in homing of PCa to the skeleton, and are consistent with a role for PITX2 in PCa metastasis to soft and bone tissues. Our findings, which significantly expand previous evidence that PITX2 is associated with risk of PCa biochemical recurrence, indicate that variation in PITX2 expression accompanies and may promote prostate tumor progression and metastasis.

  20. Association of single nucleotide polymorphisms in Wnt signaling pathway genes with breast cancer in Saudi patients.

    Directory of Open Access Journals (Sweden)

    Mohammad Saud Alanazi

    Full Text Available Breast cancer is a complex heterogeneous disease involving genetic and epigenetic alterations in genes encoding proteins that are components of various signaling pathways. Candidate gene approach have identified association of genetic variants in the Wnt signaling pathway genes and increased susceptibility to several diseases including breast cancer. Due to the rarity of somatic mutations in key genes of Wnt pathway, we investigated the association of genetic variants in these genes with predisposition to breast cancers. We performed a case-control study to identify risk variants by examining 15 SNPs located in 8 genes associated with Wnt signaling. Genotypic analysis of individual locus showed statistically significant association of five SNPs located in β-catenin, AXIN2, DKK3, SFRP3 and TCF7L2 with breast cancers. Increased risk was observed only with the SNP in β-catenin while the other four SNPs conferred protection against breast cancers. Majority of these associations persisted after stratification of the cases based on estrogen receptor status and age of on-set of breast cancer. The rs7775 SNP in exon 6 of SFRP3 gene that codes for either arginine or glycine exhibited very strong association with breast cancer, even after Bonferroni's correction. Apart from these five variants, rs3923086 in AXIN2 and rs3763511 in DKK4 that did not show any association in the overall population were significantly associated with early on-set and estrogen receptor negative breast cancers, respectively. This is the first study to utilize pathway based approach to identify association of risk variants in the Wnt signaling pathway genes with breast cancers. Confirmation of our findings in larger populations of different ethnicities would provide evidence for the role of Wnt pathway as well as screening markers for early detection of breast carcinomas.

  1. A Wnt/Notch/Pax7 signaling network supports tissue integrity in tongue development.

    Science.gov (United States)

    Zhu, Xiao-Jing; Yuan, Xueyan; Wang, Min; Fang, Yukun; Liu, Yudong; Zhang, Xiaoyun; Yang, Xueqin; Li, Yan; Li, Jianying; Li, Feixue; Dai, Zhong-Min; Qiu, Mengsheng; Zhang, Ze; Zhang, Zunyi

    2017-06-02

    The tongue is one of the major structures involved in human food intake and speech. Tongue malformations such as aglossia, microglossia, and ankyloglossia are congenital birth defects, greatly affecting individuals' quality of life. However, the molecular basis of the tissue-tissue interactions that ensure tissue morphogenesis to form a functional tongue remains largely unknown. Here we show that Shh Cre -mediated epithelial deletion of Wntless ( Wls ), the key regulator for intracellular Wnt trafficking, leads to lingual hypoplasia in mice. Disruption of epithelial Wnt production by Wls deletion in epithelial cells led to a failure in lingual epidermal stratification and loss of the lamina propria and the underlying superior longitudinal muscle in developing mouse tongues. These defective phenotypes resulted from a reduction in epithelial basal cells positive for the basal epidermal marker protein p63 and from impaired proliferation and differentiation in connective tissue and paired box 3 (Pax3)- and Pax7-positive muscle progenitor cells. We also found that epithelial Wnt production is required for activation of the Notch signaling pathway, which promotes proliferation of myogenic progenitor cells. Notch signaling in turn negatively regulated Wnt signaling during tongue morphogenesis. We further show that Pax7 is a direct Notch target gene in the embryonic tongue. In summary, our findings demonstrate a key role for the lingual epithelial signals in supporting the integrity of the lamina propria and muscular tissue during tongue development and that a Wnt/Notch/Pax7 genetic hierarchy is involved in this development. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Long-Term Expansion, Enhanced Chondrogenic Potential, and Suppression of Endochondral Ossification of Adult Human MSCs via WNT Signaling Modulation

    Directory of Open Access Journals (Sweden)

    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.

  3. Dullard/Ctdnep1 modulates WNT signalling activity for the formation of primordial germ cells in the mouse embryo.

    Directory of Open Access Journals (Sweden)

    Satomi S Tanaka

    Full Text Available Dullard/Ctdnep1 is a member of the serine/threonine phosphatase family of the C-terminal domain of eukaryotic RNA polymerase II. Embryos lacking Dullard activity fail to form primordial germ cells (PGCs. In the mouse, the formation of PGCs is influenced by BMP4 and WNT3 activity. Although Dullard is reputed to negatively regulate BMP receptor function, in this study we found mutations in Dullard had no detectable effect on BMP4 and p-Smad activity. Furthermore Dullard mutations did not influence the dosage-dependent inductive effect of Bmp4 in PGC formation. However, Dullard may function as a positive regulator of WNT signalling. Combined loss of one copy each of Dullard and Wnt3 had a synergistic effect on the reduction of PGC numbers in the compound heterozygous embryo. In addition, loss of Dullard function was accompanied by down-regulation of WNT/β-catenin signalling activity and a reduction in the level of Dishevelled 2 (Dvl2. Therefore, Dullard may play a role in the fine-tuning of WNT signalling activity by modulating the expression of ligands/antagonists and the availability of Dvl2 protein during specification of the germ cell lineage.

  4. Wnt/β-Catenin and Sonic Hedgehog Pathways Interact in the Regulation of the Development of the Dorsal Mesenchymal Protrusion

    Science.gov (United States)

    Briggs, Laura E.; Burns, Tara A.; Lockhart, Marie M.; Phelps, Aimee L.; Van den Hoff, Maurice J.B.; Wessels, Andy

    2016-01-01

    Background The dorsal mesenchymal protrusion (DMP) is a second heart field (SHF) derived tissue involved in cardiac septation. Molecular mechanisms controlling SHF/DMP development include the Bone Morphogenetic Protein and Wnt/β-catenin signaling pathways. Reduced expression of components in these pathways leads to inhibition of proliferation of the SHF/DMP precursor population and failure of the DMP to develop. While the Sonic Hedgehog (Shh) pathway has also been demonstrated to be critically important for SHF/DMP development and atrioventricular septation, its role in the regulation of SHF proliferation is contentious. Results Tissue-specific deletion of the Shh receptor Smoothened from the SHF resulted in compromised DMP formation and atrioventricular septal defects (AVSDs). Immunohistochemical analysis at critical stages of DMP development showed significant proliferation defect as well as reduction in levels of the Wnt/β-catenin pathway-intermediates β-catenin, Lef1, and Axin2. To determine whether the defects seen in the conditional Smoothened knock-out mouse could be attributed to reduced Wnt/β-catenin signaling, LiCl, a pharmacological activator of this Wnt/β-catenin pathway, was administered. This resulted in restoration of proliferation and partial rescue of the AVSD phenotype. Conclusions The data presented suggest that the Wnt/β-catenin pathway interact with the Shh pathway in the regulation of SHF/DMP-precursor proliferation and, hence, the development of the DMP. PMID:26297872

  5. Selective ligand recognition by a diversity-generating retroelement variable protein.

    Directory of Open Access Journals (Sweden)

    Jason L Miller

    2008-06-01

    Full Text Available Diversity-generating retroelements (DGRs recognize novel ligands through massive protein sequence variation, a property shared uniquely with the adaptive immune response. Little is known about how recognition is achieved by DGR variable proteins. Here, we present the structure of the Bordetella bacteriophage DGR variable protein major tropism determinant (Mtd bound to the receptor pertactin, revealing remarkable adaptability in the static binding sites of Mtd. Despite large dissimilarities in ligand binding mode, principles underlying selective recognition were strikingly conserved between Mtd and immunoreceptors. Central to this was the differential amplification of binding strengths by avidity (i.e., multivalency, which not only relaxed the demand for optimal complementarity between Mtd and pertactin but also enhanced distinctions among binding events to provide selectivity. A quantitatively similar balance between complementarity and avidity was observed for Bordetella bacteriophage DGR as occurs in the immune system, suggesting that variable repertoires operate under a narrow set of conditions to recognize novel ligands.

  6. Pinkbar is an epithelial-specific BAR domain protein that generates planar membrane structures

    Energy Technology Data Exchange (ETDEWEB)

    Pykäläinen, Anette; Boczkowska, Malgorzata; Zhao, Hongxia; Saarikangas, Juha; Rebowski, Grzegorz; Jansen, Maurice; Hakanen, Janne; Koskela, Essi V.; Peränen, Johan; Vihinen, Helena; Jokitalo, Eija; Salminen, Marjo; Ikonen, Elina; Dominguez, Roberto; Lappalainen, Pekka (Helsinki); (Penn)

    2013-05-29

    Bin/amphipysin/Rvs (BAR)-domain proteins sculpt cellular membranes and have key roles in processes such as endocytosis, cell motility and morphogenesis. BAR domains are divided into three subfamilies: BAR- and F-BAR-domain proteins generate positive membrane curvature and stabilize cellular invaginations, whereas I-BAR-domain proteins induce negative curvature and stabilize protrusions. We show that a previously uncharacterized member of the I-BAR subfamily, Pinkbar, is specifically expressed in intestinal epithelial cells, where it localizes to Rab13-positive vesicles and to the plasma membrane at intercellular junctions. Notably, the BAR domain of Pinkbar does not induce membrane tubulation but promotes the formation of planar membrane sheets. Structural and mutagenesis analyses reveal that the BAR domain of Pinkbar has a relatively flat lipid-binding interface and that it assembles into sheet-like oligomers in crystals and in solution, which may explain its unique membrane-deforming activity.

  7. The generation of superoxide anion by the UVA irradiation of human lens proteins

    Energy Technology Data Exchange (ETDEWEB)

    Linetsky, M.; James, H.-L.; Ortwerth, B.J. [Missouri Univ., Columbia, MO (United States)

    1996-07-01

    In this study we report the generation of superoxide anion and hydrogen peroxide by a water-insoluble protein fraction from aged human lenses in response to UVA light. Irradiation with 1.5 kJ cm{sup -2} of UVA light (> 338 nm) over a 1 hr period caused the formation of 20 {+-} 0.1 {mu}M superoxide radical and 37 {+-} 0.5 {mu}M hydrogen peroxide. A linear photolysis of SH-groups (21 nmol ml{sup -1}, 26%), His (117 nmol ml{sup -1}, 26%) and Trp (72 nmol ml{sup -1}, 27%) residues was seen following 60 min of irradiation. The addition of SOD, however, had no effect on the photolytic destruction of any of these amino acid residues. Incubation of the human WISS proteins and bovine {alpha}-crystallin in the presence of 43-49 {mu}m of O{sub 2}{sup -} generated in a xanthine oxidase/hypoanthine system over a 1 hr period, caused no loss of histidine, little or no loss of tryptophan and loss of 7-9 nmol ml{sup -1} of syfhydryl groups with both proteins. This argues that O{sub 2}{sup -} can only account for the destruction of at most 4-8 nmol SH-groups in human water-insoluble proteins following 1 hr of UVA irradiation. (author).

  8. Protein nutrient value of Agaricus bazei murrill mutant J3 induced by 60Co γ-irradiation in different generations

    International Nuclear Information System (INIS)

    Jiang Zhihe; Lin Yong; Xiao Shuxia

    2004-01-01

    Protein nutritional values of Agaricus bazei Murrill mutant J 3 and original strain J 1 were compared by non-biological evaluation methods. The results showed that five protein indexes in the fruitbodies of M 1 and M 6 generations of Agaricus bazei Murrill mutant J 3 were higher than that of original strain J 1 ; four protein indexes in M 4 and M 5 generations were higher than that of original strain J 1 ; and six protein indexes in M 2 and M 3 generations were higher than that of original strain J 1 . It was concluded that the protein nutritional values of Agaricus bazei Murrill mutant J 3 was better than that of original strain J 1 . Except the ratio scores of amino acids had little change in the different generations, the other indexes in strain J 3 Agaricus bazei Murrill showed that the heredity efficiencies of the proteins was rather stable. (authors)

  9. 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...... and in a multitude of diseases. Although the first evidence for interactions between syndecans and Wnts dates back to 1997, the number of studies connecting these pathways is low, and many open questions remained unanswered. In this review, syndecan's involvement in Wnt signaling pathways as well as some...

  10. Probing the canonicity of the Wnt/Wingless signaling pathway.

    Directory of Open Access Journals (Sweden)

    Alexandra Franz

    2017-04-01

    Full Text Available The hallmark of canonical Wnt signaling is the transcriptional induction of Wnt target genes by the beta-catenin/TCF complex. Several studies have proposed alternative interaction partners for beta-catenin or TCF, but the relevance of potential bifurcations in the distal Wnt pathway remains unclear. Here we study on a genome-wide scale the requirement for Armadillo (Arm, Drosophila beta-catenin and Pangolin (Pan, Drosophila TCF in the Wnt/Wingless(Wg-induced transcriptional response of Drosophila Kc cells. Using somatic genetics, we demonstrate that both Arm and Pan are absolutely required for mediating activation and repression of target genes. Furthermore, by means of STARR-sequencing we identified Wnt/Wg-responsive enhancer elements and found that all responsive enhancers depend on Pan. Together, our results confirm the dogma of canonical Wnt/Wg signaling and argue against the existence of distal pathway branches in this system.

  11. Common activation of canonical Wnt signaling in pancreatic adenocarcinoma.

    Directory of Open Access Journals (Sweden)

    Marina Pasca di Magliano

    2007-11-01

    Full Text Available Pancreatic ductal adenocarcinoma (PDA is an extremely aggressive malignancy, which carries a dismal prognosis. Activating mutations of the Kras gene are common to the vast majority of human PDA. In addition, recent studies have demonstrated that embryonic signaling pathway such as Hedgehog and Notch are inappropriately upregulated in this disease. The role of another embryonic signaling pathway, namely the canonical Wnt cascade, is still controversial. Here, we use gene array analysis as a platform to demonstrate general activation of the canonical arm of the Wnt pathway in human PDA. Furthermore, we provide evidence for Wnt activation in mouse models of pancreatic cancer. Our results also indicate that Wnt signaling might be activated downstream of Hedgehog signaling, which is an early event in PDA evolution. Wnt inhibition blocked proliferation and induced apoptosis of cultured adenocarcinoma cells, thereby providing evidence to support the development of novel therapeutical strategies for Wnt inhibition in pancreatic adenocarcinoma.

  12. 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

  13. A Wnt/β-catenin negative feedback loop inhibits interleukin-1-induced matrix metalloproteinase expression in human articular chondrocytes.

    Science.gov (United States)

    Ma, Bin; van Blitterswijk, Clemens A; Karperien, Marcel

    2012-08-01

    The results of recent animal studies suggest that activation of Wnt/β-catenin signaling in articular chondrocytes might be a driving factor in the pathogenesis of osteoarthritis (OA) by stimulating, for instance, the expression of matrix metalloproteinases (MMPs). The aim of this study was to investigate the role of Wnt/β-catenin signaling in interleukin-1β (IL-1β)-induced MMP expression in human chondrocytes. Primary cultures of human, murine, and bovine articular chondrocytes as well as human mesenchymal stem cells and mouse embryonic fibroblasts were used in the experiments. Multiple strategies for the activation and inhibition of signaling pathways were utilized. Reporter assays and coimmunoprecipitation were performed to study the interaction between β-catenin and NF-κB. In contrast to the role of Wnt/β-catenin in animal chondrocytes, in human chondrocytes it was a potent inhibitor of MMP-1, MMP-3, and MMP-13 expression and generic MMP activity both in basal conditions and after IL-1β stimulation. This effect was independent of the T cell factor/lymphoid enhancer factor family of transcription factors but rather was attributable to an inhibitory protein-protein interaction between β-catenin and NF-κB. IL-1β indirectly activated β-catenin signaling by inducing canonical Wnt-7B expression and by inhibiting the expression of canonical Wnt antagonists. Wnt/β-catenin signaling in human chondrocytes had an unexpected anticatabolic role by counteracting NF-κB-mediated MMP expression induced by IL-1β in a negative feedback loop. Copyright © 2012 by the American College of Rheumatology.

  14. Coordination of Heparan Sulfate Proteoglycans with Wnt Signaling To Control Cellular Migrations and Positioning in Caenorhabditis elegans.

    Science.gov (United States)

    Saied-Santiago, Kristian; Townley, Robert A; Attonito, John D; da Cunha, Dayse S; Díaz-Balzac, Carlos A; Tecle, Eillen; Bülow, Hannes E

    2017-08-01

    Heparan sulfates (HS) are linear polysaccharides with complex modification patterns, which are covalently bound via conserved attachment sites to core proteins to form heparan sulfate proteoglycans (HSPGs). HSPGs regulate many aspects of the development and function of the nervous system, including cell migration, morphology, and network connectivity. HSPGs function as cofactors for multiple signaling pathways, including the Wnt-signaling molecules and their Frizzled receptors. To investigate the functional interactions among the HSPG and Wnt networks, we conducted genetic analyses of each, and also between these networks using five cellular migrations in the nematode Caenorhabditis elegans We find that HSPG core proteins act genetically in a combinatorial fashion dependent on the cellular contexts. Double mutant analyses reveal distinct redundancies among HSPGs for different migration events, and different cellular migrations require distinct heparan sulfate modification patterns. Our studies reveal that the transmembrane HSPG SDN-1/Syndecan functions within the migrating cell to promote cellular migrations, while the GPI-linked LON-2/Glypican functions cell nonautonomously to establish the final cellular position. Genetic analyses with the Wnt-signaling system show that (1) a given HSPG can act with different Wnts and Frizzled receptors, and that (2) a given Wnt/Frizzled pair acts with different HSPGs in a context-dependent manner. Lastly, we find that distinct HSPG and Wnt/Frizzled combinations serve separate functions to promote cellular migration and establish position of specific neurons. Our studies suggest that HSPGs use structurally diverse glycans in coordination with Wnt-signaling pathways to control multiple cellular behaviors, including cellular and axonal migrations and, cellular positioning. Copyright © 2017 by the Genetics Society of America.

  15. Generation of Functional Human Cardiac Progenitor Cells by High-Efficiency Protein Transduction.

    Science.gov (United States)

    Li, Xiao-Hong; Li, Qianqian; Jiang, Lin; Deng, Chunyu; Liu, Zaiyi; Fu, Yongheng; Zhang, Mengzhen; Tan, Honghong; Feng, Yuliang; Shan, Zhixin; Wang, Jianjun; Yu, Xi-Yong

    2015-12-01

    The reprogramming of fibroblasts to induced pluripotent stem cells raises the possibility that somatic cells could be directly reprogrammed to cardiac progenitor cells (CPCs). The present study aimed to assess highly efficient protein-based approaches to reduce or eliminate the genetic manipulations to generate CPCs for cardiac regeneration therapy. A combination of QQ-reagent-modified Gata4, Hand2, Mef2c, and Tbx5 and three cytokines rapidly and efficiently reprogrammed human dermal fibroblasts (HDFs) into CPCs. This reprogramming process enriched trimethylated histone H3 lysine 4, monoacetylated histone H3 lysine 9, and Baf60c at the Nkx2.5 cardiac enhancer region by the chromatin immunoprecipitation quantitative polymerase chain reaction assay. Protein-induced CPCs transplanted into rat hearts after myocardial infarction improved cardiac function, and this was related to differentiation into cardiomyocyte-like cells. These findings demonstrate that the highly efficient protein-transduction method can directly reprogram HDFs into CPCs. This protein reprogramming strategy lays the foundation for future refinements both in vitro and in vivo and might provide a source of CPCs for regenerative approaches. The findings from the present study have demonstrated an efficient protein-transduction method of directly reprogramming fibroblasts into cardiac progenitor cells. These results have great potential in cell-based therapy for cardiovascular diseases. ©AlphaMed Press.

  16. Dimeric and trimeric fusion proteins generated with fimbrial adhesins of uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Víctor Manuel Luna-Pineda

    2016-10-01

    Full Text Available Urinary tract infections (UTIs are associated with high rates of morbidity and mortality worldwide, and uropathogenic Escherichia coli (UPEC is the main etiologic agent. Fimbriae assembled on the bacterial surface are essential for adhesion in the urinary tract epithelium. In this study, the FimH, CsgA, and PapG adhesins were fused to generate biomolecules as potential target vaccines against UTIs. The fusion protein design was generated using bioinformatics tools, and template fusion gene sequences were synthesized by GenScript in the following order fimH-csgA-papG-fimH-csgA (fcpfc linked to the nucleotide sequence encoding the EAAAK5 peptide. Monomeric (fimH, csgA, and papG, dimeric (fimH-csgA, and trimeric (fimH-csgA-papG genes were cloned into the pLATE31 expression vector and generated products of 1040, 539, 1139, 1442, and 2444 bp, respectively. Fusion protein expression in BL21 E. coli was induced with 1 mM IPTG, and His-tagged fusion proteins were purified under denaturing conditions and refolded by dialysis using C-buffer. Coomassie blue-stained SDS-PAGE gels and Western blot analysis revealed bands of 29.5, 11.9, 33.9, 44.9, and 82.1 kDa corresponding to FimH, CsgA, PapG, FC, and FCP proteins, respectively. Mass spectrometry analysis by MALDI-TOF/TOF revealed specific peptides that confirmed the fusion protein structures. Dynamic light scattering analysis revealed the polydispersed state of the fusion proteins. The FimH, CsgA, and PapG stimulated the release of 372 to 398 pg/mL IL-6; interestingly, the FC and FCP stimulated the release of 464.79 pg/mL (p ≤ 0.018 and 521.24 pg/mL (p ≤ 0.002 IL-6, respectively. In addition, the FC and FCP stimulated the release of 398.52 pg/mL (p ≤ 0.001 and 450.40 pg/mL (p ≤ 0.002 IL-8, respectively. High levels of IgA and IgG antibodies in human sera reacted against the fusion proteins, and under identical conditions, low levels of IgA and IgG antibodies were detected in human urine. Rabbit

  17. Dimeric and Trimeric Fusion Proteins Generated with Fimbrial Adhesins of UropathogenicEscherichia coli.

    Science.gov (United States)

    Luna-Pineda, Víctor M; Reyes-Grajeda, Juan Pablo; Cruz-Córdova, Ariadnna; Saldaña-Ahuactzi, Zeus; Ochoa, Sara A; Maldonado-Bernal, Carmen; Cázares-Domínguez, Vicenta; Moreno-Fierros, Leticia; Arellano-Galindo, José; Hernández-Castro, Rigoberto; Xicohtencatl-Cortes, Juan

    2016-01-01

    Urinary tract infections (UTIs) are associated with high rates of morbidity and mortality worldwide, and uropathogenic Escherichia coli (UPEC) is the main etiologic agent. Fimbriae assembled on the bacterial surface are essential for adhesion to the urinary tract epithelium. In this study, the FimH, CsgA, and PapG adhesins were fused to generate biomolecules for use as potential target vaccines against UTIs. The fusion protein design was generated using bioinformatics tools, and template fusion gene sequences were synthesized by GenScript in the following order fimH - csgA - papG - fimH - csgA ( fcpfc ) linked to the nucleotide sequence encoding the [EAAAK] 5 peptide. Monomeric ( fimH, csgA , and papG ), dimeric ( fimH-csgA ), and trimeric ( fimH - csgA - papG ) genes were cloned into the pLATE31 expression vector and generated products of 1040, 539, 1139, 1442, and 2444 bp, respectively. Fusion protein expression in BL21 E. coli was induced with 1 mM IPTG, and His-tagged proteins were purified under denaturing conditions and refolded by dialysis using C-buffer. Coomassie blue-stained SDS-PAGE gels and Western blot analysis revealed bands of 29.5, 11.9, 33.9, 44.9, and 82.1 kDa, corresponding to FimH, CsgA, PapG, FC, and FCP proteins, respectively. Mass spectrometry analysis by MALDI-TOF/TOF revealed specific peptides that confirmed the fusion protein structures. Dynamic light scattering analysis revealed the polydispersed state of the fusion proteins. FimH, CsgA, and PapG stimulated the release of 372-398 pg/mL IL-6; interestingly, FC and FCP stimulated the release of 464.79 pg/mL ( p ≤ 0.018) and 521.24 pg/mL ( p ≤ 0.002) IL-6, respectively. In addition, FC and FCP stimulated the release of 398.52 pg/mL ( p ≤ 0.001) and 450.40 pg/mL ( p ≤ 0.002) IL-8, respectively. High levels of IgA and IgG antibodies in human sera reacted against the fusion proteins, and under identical conditions, low levels of IgA and IgG antibodies were detected in human urine

  18. Novel Mutation of LRP6 Identified in Chinese Han Population Links Canonical WNT Signaling to Neural Tube Defects.

    Science.gov (United States)

    Shi, Zhiwen; Yang, Xueyan; Li, Bin-Bin; Chen, Shuxia; Yang, Luming; Cheng, Liangping; Zhang, Ting; Wang, Hongyan; Zheng, Yufang

    2018-01-15

    Neural tube defects (NTDs), the second most frequent cause of human congenital abnormalities, are debilitating birth defects due to failure of neural tube closure. It has been shown that noncanonical WNT/planar cell polarity (PCP) signaling is required for convergent extension (CE), the initiation step of neural tube closure (NTC). But the effect of canonical WNT//β-catenin signaling during NTC is still elusive. LRP6 (low density lipoprotein receptor related proteins 6) was identified as a co-receptor for WNT/β-catenin signaling, but recent studies showed that it also can mediate WNT/PCP signaling. In this study, we screened mutations in the LRP6 gene in 343 NTDs and 215 ethnically matched normal controls of Chinese Han population. Three rare missense mutations (c.1514A>G, p.Y505C); c.2984A>G, p.D995G; and c.4280C>A, p.P1427Q) of the LRP6 gene were identified in Chinese NTD patients. The Y505C mutation is a loss-of-function mutation on both WNT/β-catenin and PCP signaling. The D995G mutation only partially lost inhibition on PCP signaling without affecting WNT/β-catenin signaling. The P1427Q mutation dramatically increased WNT/β-catenin signaling but only mildly loss of inhibition on PCP signaling. All three mutations failed to rescue CE defects caused by lrp6 morpholino oligos knockdown in zebrafish. Of interest, when overexpressed, D995G did not induce any defects, but Y505C and P1427Q caused more severe CE defects in zebrafish. Our results suggested that over-active canonical WNT signaling induced by gain-of-function mutation in LRP6 could also contribute to human NTDs, and a balanced WNT/β-catenin and PCP signaling is probably required for proper neural tube development. Birth Defects Research 110:63-71, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  19. Notch and Wnt signaling in the emergence of hematopoietic stem cells

    DEFF Research Database (Denmark)

    Bigas, Anna; Guiu, Jordi; Gama-Norton, Leonor

    2013-01-01

    Hematopoietic stem cells (HSC), which reside in the marrow of adult mammals and sustain hematopoiesis for the lifetime of the organism, are specified and generated during embryonic development. We are just beginning to understand how HSC develop from more primitive cells and the complexity of the...... of the signaling pathways involved. In this work, we review the role of two crucial pathways, Notch and Wnt, in the specification and development of HSC and their nascent microenvironment, the arterial vessels....

  20. Epilepsy and the Wnt Signaling Pathway

    Science.gov (United States)

    2016-08-01

    Tufts University School of Medicine Boston, MA 02111 REPORT DATE: August 2016 TYPE OF REPORT: Final PREPARED FOR: U.S. Army Medical Research and...Medical Campus Building 500 Mail Stop F428, PO Box 6508 Aurora, CO 80045 Tufts University School of Medicine Dept. of DMCB Jaharis 614 150...delineating a time course for Wnt signaling in mouse to complement Audrey Yee’s studies in the rat. We have complementary evidence for the increase

  1. The inhibitory influence of adipose tissue-derived mesenchymal stem cell environment and Wnt antagonism on breast tumour cell lines.

    Science.gov (United States)

    Visweswaran, Malini; Arfuso, Frank; Dilley, Rodney J; Newsholme, Philip; Dharmarajan, Arun

    2018-02-01

    Tumours exhibit a heterogeneous mix of cell types that reciprocally regulate their growth in the tumour stroma, considerably affecting the progression of the disease. Both adipose-derived mesenchymal stem cells and Wnt signalling pathway are vital in driving breast tumour growth. Hence, we examined the effect of secreted factors released by adipose-derived mesenchymal stem cells, and further explored the anti-tumour property of the Wnt antagonist secreted frizzled-related protein 4 (sFRP4) on MCF-7 and MDA-MB-231 breast tumour cells. We observed that conditioned medium and extracellular matrix derived from adipose-derived mesenchymal stem cells inhibited tumour viability. The inhibitory effect of the conditioned medium was retained within its low molecular weight and non-protein component. The conditioned medium also induced apoptosis accompanied by a decrease in the mitochondrial membrane potential in tumour cells, Furthermore, it downregulated the protein expression of active β-catenin and Cyclin D1, which are major target proteins of the Wnt signalling pathway, and reduced the expression of anti-apoptotic protein Bcl-xL. The combination of conditioned medium and sFRP4 further potentiated the effects, depending on the tumour cell line and experimental assay. We conclude that factors derived from conditioned medium of adipose-derived mesenchymal stem cells and sFRP4 significantly decreased the tumour cell viability and migration rates (MCF-7), accompanied with an enhanced apoptotic activity through inhibition of canonical Wnt signalling. Besides giving an insight to possible paracrine interactions and influence of signalling pathways, reflective of a breast tumour microenvironment, this study emphasises the utilization of cell free-secreted factors and Wnt antagonists to improve conventional anti-cancer strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. TC-1 (c8orf4) enhances aggressive biologic behavior in lung cancer through the Wnt/β-catenin pathway.

    Science.gov (United States)

    Su, Kai; Huang, Lijun; Li, Wenhai; Yan, Xiaolong; Li, Xiaofei; Zhang, Zhipei; Jin, Faguang; Lei, Jie; Ba, Guangzhen; Liu, Boya; Wang, Xiaoping; Wang, Yunjie

    2013-11-01

    The thyroid cancer-1 (TC-1) or c8orf4 gene encodes a 106-residue naturally disordered protein that has been found to be associated with thyroid, gastric, and breast cancer. A recent study has indicated that the protein functions as a positive regulator in the Wnt/β-catenin signaling pathway in human breast cancer. However, no research has been done in the area of lung cancer. Therefore, the goal of the present study was to confirm the relationship among TC-1, lung cancer, and the Wnt/β-catenin signaling pathway. The expression of TC-1 was immunohistochemically examined in 147 patients with non-small-cell lung cancer. TC-1-overexpressed and silenced A549 cells were infected using lentivirus and MTT cell proliferation analysis, and Matrigel invasion assays and scratch-wound assays were performed to confirm the biologic behavioral changes in different A549 cell subsets. The Wnt/β-catenin signaling pathway, key gene β-catenin, target genes of vascular endothelial growth factor, cyclin D1, matrix metalloproteinase-7, c-myc, and survivin were tested at the mRNA and protein level. TC-1 was detected in 97 of the 147 non-small-cell lung cancer primary tumor specimens, and its expression correlated with the TNM stage and regional lymph node metastasis (P cell line. Furthermore, expression of TC-1 protein affected the Wnt/β-catenin signaling pathway's downstream genes, such as vascular endothelial growth factor and matrix metalloproteinase-7, at the mRNA and protein level. TC-1 expression is associated with aggressive biologic behavior in lung cancer and might coordinate with the Wnt/β-catenin pathway as a positive upstream regulator that induces these behaviors. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Next Generation Protein Interactomes for Plant Systems Biology and Biomass Feedstock Research

    Energy Technology Data Exchange (ETDEWEB)

    Ecker, Joseph Robert [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Trigg, Shelly [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Univ. of California, San Diego, CA (United States). Biological Sciences Dept.; Garza, Renee [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Song, Haili [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; MacWilliams, Andrew [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Nery, Joseph [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Reina, Joaquin [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Bartlett, Anna [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Castanon, Rosa [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Goubil, Adeline [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Feeney, Joseph [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; O' Malley, Ronan [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Huang, Shao-shan Carol [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Zhang, Zhuzhu [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.; Galli, Mary [The Salk Inst. for Biological Studies, La Jolla, CA (United States). Genome Analysis and Plant Biology Lab.

    2016-11-30

    Biofuel crop cultivation is a necessary step in heading towards a sustainable future, making their genomic studies a priority. While technology platforms that currently exist for studying non-model crop species, like switch-grass or sorghum, have yielded large quantities of genomic and expression data, still a large gap exists between molecular mechanism and phenotype. The aspect of molecular activity at the level of protein-protein interactions has recently begun to bridge this gap, providing a more global perspective. Interactome analysis has defined more specific functional roles of proteins based on their interaction partners, neighborhoods, and other network features, making it possible to distinguish unique modules of immune response to different plant pathogens(Jiang, Dong, and Zhang 2016). As we work towards cultivating heartier biofuel crops, interactome data will lead to uncovering crop-specific defense and development networks. However, the collection of protein interaction data has been limited to expensive, time-consuming, hard-to-scale assays that mostly require cloned ORF collections. For these reasons, we have successfully developed a highly scalable, economical, and sensitive yeast two-hybrid assay, ProCREate, that can be universally applied to generate proteome-wide primary interactome data. ProCREate enables en masse pooling and massively paralleled sequencing for the identification of interacting proteins by exploiting Cre-lox recombination. ProCREate can be used to screen ORF/cDNA libraries from feedstock plant tissues. The interactome data generated will yield deeper insight into many molecular processes and pathways that can be used to guide improvement of feedstock productivity and sustainability.

  4. 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

    patterns induced by Wnt3a treatment in two hMSC lines: hMSC-LRP5(T253) and hMSC-LRP5(T244) cells carrying known mutations of Wnt co-receptor LRP5 (T253I or T244M) that either enhances or represses canonical Wnt signaling, respectively. Wnt3a treatment of hMSC activated not only canonical Wnt signaling...

  5. Neuroprotective effect of rapamycin on spinal cord injury via activation of the Wnt/β-catenin signaling pathway

    Directory of Open Access Journals (Sweden)

    Kai Gao

    2015-01-01

    Full Text Available The Wnt/β-catenin signaling pathway plays a crucial role in neural development, axonal guidance, neuropathic pain remission and neuronal survival. In this study, we initially examined the effect of rapamycin on the Wnt/β-catenin signaling pathway after spinal cord injury, by intraperitoneally injecting spinal cord injured rats with rapamycin over 2 days. Western blot analysis and immunofluorescence staining were used to detect the expression levels of β-catenin protein, ca-spase-3 protein and brain-derived neurotrophic factor protein, components of the Wnt/β-catenin signaling pathway. Rapamycin increased the levels of β-catenin and brain-derived neurotrophic factor in the injured spinal cord, improved the pathological morphology at the injury site, reduced the loss of motor neurons, and promoted motor functional recovery in rats after spinal cord injury. Our experimental findings suggest that the neuroprotective effect of rapamycin intervention is mediated through activation of the Wnt/β-catenin signaling pathway after spinal cord injury.

  6. Protein Nano-Object Integrator (ProNOI for generating atomic style objects for molecular modeling

    Directory of Open Access Journals (Sweden)

    Smith Nicholas

    2012-12-01

    Full Text Available Abstract Background With the progress of nanotechnology, one frequently has to model biological macromolecules simultaneously with nano-objects. However, the atomic structures of the nano objects are typically not available or they are solid state entities. Because of that, the researchers have to investigate such nano systems by generating models of the nano objects in a manner that the existing software be able to carry the simulations. In addition, it should allow generating composite objects with complex shape by combining basic geometrical figures and embedding biological macromolecules within the system. Results Here we report the Protein Nano-Object Integrator (ProNOI which allows for generating atomic-style geometrical objects with user desired shape and dimensions. Unlimited number of objects can be created and combined with biological macromolecules in Protein Data Bank (PDB format file. Once the objects are generated, the users can use sliders to manipulate their shape, dimension and absolute position. In addition, the software offers the option to charge the objects with either specified surface or volumetric charge density and to model them with user-desired dielectric constants. According to the user preference, the biological macromolecule atoms can be assigned charges and radii according to four different force fields: Amber, Charmm, OPLS and PARSE. The biological macromolecules and the atomic-style objects are exported as a position, charge and radius (PQR file, or if a default dielectric constant distribution is not selected, it is exported as a position, charge, radius and epsilon (PQRE file. As illustration of the capabilities of the ProNOI, we created a composite object in a shape of a robot, aptly named the Clemson Robot, whose parts are charged with various volumetric charge densities and holds the barnase-barstar protein complex in its hand. Conclusions The Protein Nano-Object Integrator (ProNOI is a convenient tool for

  7. A mathematical model for generating bipartite graphs and its application to protein networks

    International Nuclear Information System (INIS)

    Nacher, J C; Ochiai, T; Hayashida, M; Akutsu, T

    2009-01-01

    Complex systems arise in many different contexts from large communication systems and transportation infrastructures to molecular biology. Most of these systems can be organized into networks composed of nodes and interacting edges. Here, we present a theoretical model that constructs bipartite networks with the particular feature that the degree distribution can be tuned depending on the probability rate of fundamental processes. We then use this model to investigate protein-domain networks. A protein can be composed of up to hundreds of domains. Each domain represents a conserved sequence segment with specific functional tasks. We analyze the distribution of domains in Homo sapiens and Arabidopsis thaliana organisms and the statistical analysis shows that while (a) the number of domain types shared by k proteins exhibits a power-law distribution, (b) the number of proteins composed of k types of domains decays as an exponential distribution. The proposed mathematical model generates bipartite graphs and predicts the emergence of this mixing of (a) power-law and (b) exponential distributions. Our theoretical and computational results show that this model requires (1) growth process and (2) copy mechanism.

  8. A mathematical model for generating bipartite graphs and its application to protein networks

    Energy Technology Data Exchange (ETDEWEB)

    Nacher, J C [Department of Complex Systems, Future University-Hakodate (Japan); Ochiai, T [Faculty of Engineering, Toyama Prefectural University (Japan); Hayashida, M; Akutsu, T [Bioinformatics Center, Institute for Chemical Research, Kyoto University (Japan)

    2009-12-04

    Complex systems arise in many different contexts from large communication systems and transportation infrastructures to molecular biology. Most of these systems can be organized into networks composed of nodes and interacting edges. Here, we present a theoretical model that constructs bipartite networks with the particular feature that the degree distribution can be tuned depending on the probability rate of fundamental processes. We then use this model to investigate protein-domain networks. A protein can be composed of up to hundreds of domains. Each domain represents a conserved sequence segment with specific functional tasks. We analyze the distribution of domains in Homo sapiens and Arabidopsis thaliana organisms and the statistical analysis shows that while (a) the number of domain types shared by k proteins exhibits a power-law distribution, (b) the number of proteins composed of k types of domains decays as an exponential distribution. The proposed mathematical model generates bipartite graphs and predicts the emergence of this mixing of (a) power-law and (b) exponential distributions. Our theoretical and computational results show that this model requires (1) growth process and (2) copy mechanism.

  9. Transposon assisted gene insertion technology (TAGIT: a tool for generating fluorescent fusion proteins.

    Directory of Open Access Journals (Sweden)

    James A Gregory

    2010-01-01

    Full Text Available We constructed a transposon (transposon assisted gene insertion technology, or TAGIT that allows the random insertion of gfp (or other genes into chromosomal loci without disrupting operon structure or regulation. TAGIT is a modified Tn5 transposon that uses Kan(R to select for insertions on the chromosome or plasmid, beta-galactosidase to identify in-frame gene fusions, and Cre recombinase to excise the kan and lacZ genes in vivo. The resulting gfp insertions maintain target gene reading frame (to the 5' and 3' of gfp and are integrated at the native chromosomal locus, thereby maintaining native expression signals. Libraries can be screened to identify GFP insertions that maintain target protein function at native expression levels, allowing more trustworthy localization studies. We here use TAGIT to generate a library of GFP insertions in the Escherichia coli lactose repressor (LacI. We identified fully functional GFP insertions and partially functional insertions that bind DNA but fail to repress the lacZ operon. Several of these latter GFP insertions localize to lacO arrays integrated in the E. coli chromosome without producing the elongated cells frequently observed when functional LacI-GFP fusions are used in chromosome tagging experiments. TAGIT thereby faciliates the isolation of fully functional insertions of fluorescent proteins into target proteins expressed from the native chromosomal locus as well as potentially useful partially functional proteins.

  10. Beyond rotamers: a generative, probabilistic model of side chains in proteins

    Directory of Open Access Journals (Sweden)

    Frellsen Jes

    2010-06-01

    Full Text Available Abstract Background Accurately covering the conformational space of amino acid side chains is essential for important applications such as protein design, docking and high resolution structure prediction. Today, the most common way to capture this conformational space is through rotamer libraries - discrete collections of side chain conformations derived from experimentally determined protein structures. The discretization can be exploited to efficiently search the conformational space. However, discretizing this naturally continuous space comes at the cost of losing detailed information that is crucial for certain applications. For example, rigorously combining rotamers with physical force fields is associated with numerous problems. Results In this work we present BASILISK: a generative, probabilistic model of the conformational space of side chains that makes it possible to sample in continuous space. In addition, sampling can be conditional upon the protein's detailed backbone conformation, again in continuous space - without involving discretization. Conclusions A careful analysis of the model and a comparison with various rotamer libraries indicates that the model forms an excellent, fully continuous model of side chain conformational space. We also illustrate how the model can be used for rigorous, unbiased sampling with a physical force field, and how it improves side chain prediction when used as a pseudo-energy term. In conclusion, BASILISK is an important step forward on the way to a rigorous probabilistic description of protein structure in continuous space and in atomic detail.

  11. Beyond rotamers: a generative, probabilistic model of side chains in proteins.

    Science.gov (United States)

    Harder, Tim; Boomsma, Wouter; Paluszewski, Martin; Frellsen, Jes; Johansson, Kristoffer E; Hamelryck, Thomas

    2010-06-05

    Accurately covering the conformational space of amino acid side chains is essential for important applications such as protein design, docking and high resolution structure prediction. Today, the most common way to capture this conformational space is through rotamer libraries - discrete collections of side chain conformations derived from experimentally determined protein structures. The discretization can be exploited to efficiently search the conformational space. However, discretizing this naturally continuous space comes at the cost of losing detailed information that is crucial for certain applications. For example, rigorously combining rotamers with physical force fields is associated with numerous problems. In this work we present BASILISK: a generative, probabilistic model of the conformational space of side chains that makes it possible to sample in continuous space. In addition, sampling can be conditional upon the protein's detailed backbone conformation, again in continuous space - without involving discretization. A careful analysis of the model and a comparison with various rotamer libraries indicates that the model forms an excellent, fully continuous model of side chain conformational space. We also illustrate how the model can be used for rigorous, unbiased sampling with a physical force field, and how it improves side chain prediction when used as a pseudo-energy term. In conclusion, BASILISK is an important step forward on the way to a rigorous probabilistic description of protein structure in continuous space and in atomic detail.

  12. Rac1 augments Wnt signaling by stimulating β-caten