51
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Cantley L, Saunders C, Guttenberg M, Candela ME, Ohta Y, Yasuhara R, Kondo N, Sgariglia F, Asai S, Zhang X, Qin L, Hecht JT, Chen D, Yamamoto M, Toyosawa S, Dormans JP, Esko JD, Yamaguchi Y, Iwamoto M, Pacifici M, Enomoto-Iwamoto M. Loss of β-catenin induces multifocal periosteal chondroma-like masses in mice. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 182:917-27. [PMID: 23274133 DOI: 10.1016/j.ajpath.2012.11.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 10/15/2012] [Accepted: 11/07/2012] [Indexed: 11/18/2022]
Abstract
Osteochondromas and enchondromas are the most common tumors affecting the skeleton. Osteochondromas can occur as multiple lesions, such as those in patients with hereditary multiple exostoses. Unexpectedly, while studying the role of β-catenin in cartilage development, we found that its conditional deletion induces ectopic chondroma-like cartilage formation in mice. Postnatal ablation of β-catenin in cartilage induced lateral outgrowth of the growth plate within 2 weeks after ablation. The chondroma-like masses were present in the flanking periosteum by 5 weeks and persisted for more than 6 months after β-catenin ablation. These long-lasting ectopic masses rarely contained apoptotic cells. In good correlation, transplants of β-catenin-deficient chondrocytes into athymic mice persisted for a longer period of time and resisted replacement by bone compared to control wild-type chondrocytes. In contrast, a β-catenin signaling stimulator increased cell death in control chondrocytes. Immunohistochemical analysis revealed that the amount of detectable β-catenin in cartilage cells of osteochondromas obtained from hereditary multiple exostoses patients was much lower than that in hypertrophic chondrocytes in normal human growth plates. The findings in our study indicate that loss of β-catenin expression in chondrocytes induces periosteal chondroma-like masses and may be linked to, and cause, the persistence of cartilage caps in osteochondromas.
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Affiliation(s)
- Leslie Cantley
- Translational Research Program in Pediatric Orthopaedics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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52
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Dawson K, Aflaki M, Nattel S. Role of the Wnt-Frizzled system in cardiac pathophysiology: a rapidly developing, poorly understood area with enormous potential. J Physiol 2012. [PMID: 23207593 DOI: 10.1113/jphysiol.2012.235382] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Abstract The Wnt-Frizzled (Fzd) G-protein-coupled receptor system, involving 19 distinct Wnt ligands and 10 Fzd receptors, plays key roles in the development and functioning of many organ systems. There is increasing evidence that Wnt-Fzd signalling is important in regulating cardiac function. Wnt-Fzd signalling primarily involves a canonical pathway, with dishevelled-1-dependent nuclear translocation of β-catenin that derepresses Wnt-sensitive gene transcription, but can also include non-canonical pathways via phospholipase-C/Ca(2+) mobilization and dishevelled-protein activation of small GTPases. Wnt-Fzd effects vary with specific ligand/receptor interactions and associated downstream pathways. This paper reviews the biochemistry and physiology of the Wnt-Fzd complex, and presents current knowledge of Wnt signalling in cardiac remodelling processes such as hypertrophy and fibrosis, as well as disease states such as myocardial infarction (MI), heart failure and arrhythmias. Wnt signalling is activated during hypertrophy; inhibiting Wnt signalling by activating glycogen synthase kinase attenuates the hypertrophic response. Wnt signalling has complex and time-dependent actions post-MI, so that either beneficial or harmful effects might result from Wnt-directed interventions. Stem cell biology, a promising area for therapeutic intervention, is highly regulated by Wnt signalling. The Wnt system regulates fibroblast function, and is prominently altered in arrhythmogenic ventricular cardiomyopathy, a familial disease involving excess deposition of fibroadipose tissue. Wnt signalling controls connexin43 expression, thereby contributing to the regulation of cardiac electrical stability and arrhythmia generation. Although much has been learned about Wnt-Fzd signalling in hypertrophy and infarction, its role is poorly understood for a broad range of other heart disorders. Much more needs to be learned for its contributions to be fully appreciated, and to permit more effective exploitation of its enormous potential in therapeutic development.
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Affiliation(s)
- Kristin Dawson
- S. Nattel: 5000 Belanger St. E, Montreal, Quebec, Canada H1T 1C8.
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53
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Abstract
30 years after the identification of WNTs, their signal transduction has become increasingly complex, with the discovery of more than 15 receptors and co-receptors in seven protein families. The recent discovery of three receptor classes for the R-spondin family of WNT agonists further adds to this complexity. What emerges is an intricate network of receptors that form higher-order ligand-receptor complexes routing downstream signalling. These are regulated both extracellularly by agonists such as R-spondin and intracellularly by post-translational modifications such as phosphorylation, proteolytic processing and endocytosis.
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Affiliation(s)
- Christof Niehrs
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, DKFZ, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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Abstract
Syndecans are transmembrane heparan sulphate proteoglycans (HSPGs) that have gained increasing interest as regulators of a variety of tissue responses, including cartilage development and remodelling. These proteoglycans are composed of a core protein to which extracellular glycosaminoglycan (GAG) chains are attached. Through these GAG chains, syndecans can interact with a variety of extracellular matrix molecules and bind to a number of soluble mediators including morphogens, growth factors, chemokines and cytokines. The structure and post-translational modification of syndecan GAG chains seem to differ not only from cell to cell, but also during different stages of cellular differentiation, leading to a complexity of syndecan function that is unique among membrane-bound HSPGs. Unlike other membrane-bound HSPGs, syndecans contain intracellular signalling motifs that can initiate signalling mainly through protein kinase C. This Review summarizes our knowledge of the biology of syndecans and the mechanisms by which binding of molecules to syndecans exert different biological effects, particularly in the joints. On the basis of the structural and functional peculiarities of syndecans, we discuss the regulation of syndecans and their roles in the developing joint as well as during degenerative and inflammatory cartilage remodelling as understood from expression studies and functional analyses involving syndecan-deficient mice.
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Affiliation(s)
- Thomas Pap
- Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Domagkstraße 3, D-48149 Münster, Germany.
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55
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Abstract
Wnt proteins comprise a major family of signaling molecules that orchestrate and influence a myriad of cell biological and developmental processes. Although our understanding of the role of Wnt signaling in regulating development and affecting disease, such as cancer, has been ever increasing, the study of the Wnt proteins themselves has been painstaking and slow moving. Despite advances in the biochemical characterization of Wnt proteins, many mysteries remain unsolved. In contrast to other developmental signaling molecules, such as fibroblast growth factors (FGF), transforming growth factors (TGFβ), and Sonic hedgehog (Shh), Wnt proteins have not conformed to many standard methods of protein production, such as bacterial overexpression, and analysis, such as ligand-receptor binding assays. The reasons for their recalcitrant nature are likely a consequence of the complex set of posttranslational modifications involving several highly specialized and poorly characterized processing enzymes. With the recent description of the first Wnt protein structure, the time is ripe to uncover and possibly resolve many of the remaining issues surrounding Wnt proteins and their interactions. Here we describe the process of maturation of Wnt from its initial translation to its eventual release from a cell and interactions in the extracellular environment.
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Affiliation(s)
- Karl Willert
- Department of Cellular and Molecular Medicine, University of California, San Diego, California 92093, USA.
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56
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Wang Q, Yang L, Alexander C, Temple S. The niche factor syndecan-1 regulates the maintenance and proliferation of neural progenitor cells during mammalian cortical development. PLoS One 2012; 7:e42883. [PMID: 22936997 PMCID: PMC3427302 DOI: 10.1371/journal.pone.0042883] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 07/13/2012] [Indexed: 12/18/2022] Open
Abstract
Neural progenitor cells (NPCs) divide and differentiate in a precisely regulated manner over time to achieve the remarkable expansion and assembly of the layered mammalian cerebral cortex. Both intrinsic signaling pathways and environmental factors control the behavior of NPCs during cortical development. Heparan sulphate proteoglycans (HSPG) are critical environmental regulators that help modulate and integrate environmental cues and downstream intracellular signals. Syndecan-1 (Sdc1), a major transmembrane HSPG, is highly enriched in the early neural germinal zone, but its function in modulating NPC behavior and cortical development has not been explored. In this study we investigate the expression pattern and function of Sdc1 in the developing mouse cerebral cortex. We found that Sdc1 is highly expressed by cortical NPCs. Knockdown of Sdc1 in vivo by in utero electroporation reduces NPC proliferation and causes their premature differentiation, corroborated in isolated cells in vitro. We found that Sdc1 knockdown leads to reduced levels of β-catenin, indicating reduced canonical Wnt signaling. Consistent with this, GSK3β inhibition helps rescue the Sdc1 knockdown phenotype, partially restoring NPC number and proliferation. Moreover, exogenous Wnt protein promotes cortical NPC proliferation, but this is prevented by Sdc1 knockdown. Thus, Sdc1 in the germinal niche is a key HSPG regulating the maintenance and proliferation of NPCs during cortical neurogenesis, in part by modulating the ability of NPCs to respond to Wnt ligands.
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Affiliation(s)
- Qingjie Wang
- Neural Stem Cell Institute, Rensselaer, New York, United States of America
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York, United States of America
| | - Landi Yang
- Neural Stem Cell Institute, Rensselaer, New York, United States of America
| | - Caroline Alexander
- McArdle Lab for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sally Temple
- Neural Stem Cell Institute, Rensselaer, New York, United States of America
- * E-mail:
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Martin A, Papa R, Nadeau NJ, Hill RI, Counterman BA, Halder G, Jiggins CD, Kronforst MR, Long AD, McMillan WO, Reed RD. Diversification of complex butterfly wing patterns by repeated regulatory evolution of a Wnt ligand. Proc Natl Acad Sci U S A 2012; 109:12632-7. [PMID: 22802635 PMCID: PMC3411988 DOI: 10.1073/pnas.1204800109] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Although animals display a rich variety of shapes and patterns, the genetic changes that explain how complex forms arise are still unclear. Here we take advantage of the extensive diversity of Heliconius butterflies to identify a gene that causes adaptive variation of black wing patterns within and between species. Linkage mapping in two species groups, gene-expression analysis in seven species, and pharmacological treatments all indicate that cis-regulatory evolution of the WntA ligand underpins discrete changes in color pattern features across the Heliconius genus. These results illustrate how the direct modulation of morphogen sources can generate a wide array of unique morphologies, thus providing a link between natural genetic variation, pattern formation, and adaptation.
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Affiliation(s)
- Arnaud Martin
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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Zhang K, Zhang J, Han L, Pu P, Kang C. Wnt/beta-catenin signaling in glioma. J Neuroimmune Pharmacol 2012; 7:740-9. [PMID: 22454041 DOI: 10.1007/s11481-012-9359-y] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 03/15/2012] [Indexed: 01/29/2023]
Abstract
Extensive data have shown that Wnt/beta-catenin signaling is associated with various disease pathologies, including an important role in tumorigenesis. Here, we review the regulation of Wnt/beta-catenin signaling in glioma, with particular focus on the expression signatures of the main components in Wnt/beta-catenin signaling, the role of key factors in Wnt/beta-catenin signaling, and crosstalk with other signaling pathways. Finally, we discuss the involvement of microRNAs in Wnt/beta-catenin signaling in glioma. This review reveals new insights into the role of Wnt/beta-catenin signaling in gliomagenesis, and highlights new therapeutic approaches for glioma, based on the modulation of the Wnt/beta-catenin pathway.
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Affiliation(s)
- Kailiang Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
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Christian JL. Morphogen gradients in development: from form to function. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2012; 1:3-15. [PMID: 23801664 PMCID: PMC3957335 DOI: 10.1002/wdev.2] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Morphogens are substances that establish a graded distribution and elicit distinct cellular responses in a dose-dependent manner. They function to provide individual cells within a field with positional information, which is interpreted to give rise to spatial patterns. Morphogens can consist of intracellular factors that set up a concentration gradient by diffusion in the cytoplasm. More commonly, morphogens comprise secreted proteins that form an extracellular gradient across a field of cells. Experimental studies and computational analyses have provided support for a number of diverse strategies by which extracellular morphogen gradients are formed. These include free diffusion in the extracellular space, restricted diffusion aided by interactions with heparan sulfate proteoglycans, transport on lipid-containing carriers or transport aided by soluble binding partners. More specialized modes of transport have also been postulated such as transcytosis, in which repeated rounds of secretion, endocytosis, and intracellular trafficking move morphogens through cells rather than around them, or cytonemes, which consist of filopodial extensions from signal-receiving cells that are hypothesized to reach out to morphogen-sending cells. Once the gradient has formed, cells must distinguish small differences in morphogen concentration and store this information even after the gradient has dissipated. This is often achieved by translating ligand concentration into a proportional increase in numbers of activated cell surface receptors that are internalized and continue to signal from endosomal compartments. Ultimately, this leads to activation of one or a few transcription factors that transduce this information into qualitatively distinct gene responses inside the nucleus.
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Affiliation(s)
- Jan L Christian
- Department of Neurobiology and Anatomy and Internal Medicine, Division of Hematology and Hematological Malignancies, University of Utah, Salt Lake City, Utah, USA.
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60
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Schulte G. International Union of Basic and Clinical Pharmacology. LXXX. The class Frizzled receptors. Pharmacol Rev 2011; 62:632-67. [PMID: 21079039 DOI: 10.1124/pr.110.002931] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The receptor class Frizzled, which has recently been categorized as a separate group of G protein-coupled receptors by the International Union of Basic and Clinical Pharmacology, consists of 10 Frizzleds (FZD(1-10)) and Smoothened (SMO). The FZDs are activated by secreted lipoglycoproteins of the Wingless/Int-1 (WNT) family, whereas SMO is indirectly activated by the Hedgehog (HH) family of proteins acting on the transmembrane protein Patched (PTCH). Recent years have seen major advances in our knowledge about these seven-transmembrane-spanning proteins, including: receptor function, molecular mechanisms of signal transduction, and the receptor's role in embryonic patterning, physiology, cancer, and other diseases. Despite intense efforts, many question marks and challenges remain in mapping receptor-ligand interaction, signaling routes, mechanisms of specificity and how these molecular details underlie disease and also the receptor's important role in physiology. This review therefore focuses on the molecular aspects of WNT/FZD and HH/SMO signaling discussing receptor structure, mechanisms of signal transduction, accessory proteins, receptor dynamics, and the possibility of targeting these signaling pathways pharmacologically.
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Affiliation(s)
- Gunnar Schulte
- Section of Receptor Biology & Signaling, Dept. of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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61
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Fuerer C, Nusse R. Lentiviral vectors to probe and manipulate the Wnt signaling pathway. PLoS One 2010; 5:e9370. [PMID: 20186325 PMCID: PMC2826402 DOI: 10.1371/journal.pone.0009370] [Citation(s) in RCA: 220] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 02/03/2010] [Indexed: 01/19/2023] Open
Abstract
Background The Wnt signaling pathway plays key roles in development, adult tissue homeostasis and stem cell maintenance. Further understanding of the function of Wnt signaling in specific cell types could benefit from lentiviral vectors expressing reporters for the Wnt pathway or vectors interfering with signaling. Methodology/Principal Findings We have developed a set of fluorescent and luminescent lentiviral vectors that report Wnt signaling activity and discriminate between negative and uninfected cells. These vectors possess a 7xTcf-eGFP or 7xTcf-FFluc (Firefly Luciferase) reporter cassette followed by either an SV40-mCherry or SV40-PuroR (puromycin N-acetyltransferase) selection cassette. We have also constructed a vector that allows drug-based selection of cells with activated Wnt signaling by placing PuroR under the control of the 7xTcf promoter. Lastly, we have expressed dominant-negative Tcf4 (dnTcf4) or constitutively active beta-catenin (β-catenin4A) from the hEF1α promoter in a SV40-PuroR or SV40-mCherry backbone to create vectors that inhibit or activate the Wnt signaling pathway. These vectors will be made available to the scientific community through Addgene. Conclusions These novel lentiviruses are efficient tools to probe and manipulate Wnt signaling. The use of a selection cassette in Wnt-reporter viruses enables discriminating between uninfected and non-responsive cells, an important requirement for experiments where selection of clones is not possible. The use of a chemiluminescent readout enables quantification of signaling. Finally, selectable vectors can be used to either inhibit or activate the Wnt signaling pathway. Altogether, these vectors can probe and modulate the Wnt signaling pathway in experimental settings where persistence of the transgene or gene transfer cannot be accomplished by non-viral techniques.
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Affiliation(s)
- Christophe Fuerer
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Roel Nusse
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
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von der Mark K, Park J, Bauer S, Schmuki P. Nanoscale engineering of biomimetic surfaces: cues from the extracellular matrix. Cell Tissue Res 2009; 339:131-53. [DOI: 10.1007/s00441-009-0896-5] [Citation(s) in RCA: 280] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 10/08/2009] [Indexed: 11/29/2022]
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