101
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Jensen M, Hoerndli FJ, Brockie PJ, Wang R, Johnson E, Maxfield D, Francis MM, Madsen DM, Maricq AV. Wnt signaling regulates acetylcholine receptor translocation and synaptic plasticity in the adult nervous system. Cell 2012; 149:173-87. [PMID: 22464329 DOI: 10.1016/j.cell.2011.12.038] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 11/08/2011] [Accepted: 12/30/2011] [Indexed: 12/20/2022]
Abstract
The adult nervous system is plastic, allowing us to learn, remember, and forget. Experience-dependent plasticity occurs at synapses--the specialized points of contact between neurons where signaling occurs. However, the mechanisms that regulate the strength of synaptic signaling are not well understood. Here, we define a Wnt-signaling pathway that modifies synaptic strength in the adult nervous system by regulating the translocation of one class of acetylcholine receptors (AChRs) to synapses. In Caenorhabditis elegans, we show that mutations in CWN-2 (Wnt ligand), LIN-17 (Frizzled), CAM-1 (Ror receptor tyrosine kinase), or the downstream effector DSH-1 (disheveled) result in similar subsynaptic accumulations of ACR-16/α7 AChRs, a consequent reduction in synaptic current, and predictable behavioral defects. Photoconversion experiments revealed defective translocation of ACR-16/α7 to synapses in Wnt-signaling mutants. Using optogenetic nerve stimulation, we demonstrate activity-dependent synaptic plasticity and its dependence on ACR-16/α7 translocation mediated by Wnt signaling via LIN-17/CAM-1 heteromeric receptors.
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Affiliation(s)
- Michael Jensen
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
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102
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Rebagay G, Yan S, Liu C, Cheung NK. ROR1 and ROR2 in Human Malignancies: Potentials for Targeted Therapy. Front Oncol 2012; 2:34. [PMID: 22655270 PMCID: PMC3356025 DOI: 10.3389/fonc.2012.00034] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/22/2012] [Indexed: 11/13/2022] Open
Abstract
Targeted therapies require cellular protein expression that meets specific requirements that will maximize effectiveness, minimize off-target toxicities, and provide an opportunity for a therapeutic effect. The receptor tyrosine kinase-like orphan receptors (ROR) are possible targets for therapy that may meet such requirements. RORs are transmembrane proteins that are part of the receptor tyrosine kinase (RTK) family. The RORs have been shown to play a role in tumor-like behavior, such as cell migration and cell invasiveness and are normally not expressed in normal adult tissue. As part of the large effort in target discovery, ROR proteins have recently been found to be expressed in human cancers. Their unique expression profiles may provide a novel class of therapeutic targets for small molecules against the kinase or for antibody-based therapies against these receptors. Being restricted on tumor cells and not on most normal tissues, RORs are excellent targets for the treatment of minimal residual disease, the final hurdle in the curative approach to many cancers, including solid tumors such as neuroblastoma. In this review, we summarize the biology of RORs as they relate to human cancer, and highlight the therapeutic approaches directed toward them.
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Affiliation(s)
- Guilly Rebagay
- Department of Pediatrics, Memorial Sloan-Kettering Cancer Center New York, NY, USA
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103
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Ossipova O, Sokol SY. Neural crest specification by noncanonical Wnt signaling and PAR-1. Development 2012; 138:5441-50. [PMID: 22110058 DOI: 10.1242/dev.067280] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neural crest (NC) cells are multipotent progenitors that form at the neural plate border, undergo epithelial-mesenchymal transition and migrate to diverse locations in vertebrate embryos to give rise to many cell types. Multiple signaling factors, including Wnt proteins, operate during early embryonic development to induce the NC cell fate. Whereas the requirement for the Wnt/β-catenin pathway in NC specification has been well established, a similar role for Wnt proteins that do not stabilize β-catenin has remained unclear. Our gain- and loss-of-function experiments implicate Wnt11-like proteins in NC specification in Xenopus embryos. In support of this conclusion, modulation of β-catenin-independent signaling through Dishevelled and Ror2 causes predictable changes in premigratory NC. Morpholino-mediated depletion experiments suggest that Wnt11R, a Wnt protein that is expressed in neuroectoderm adjacent to the NC territory, is required for NC formation. Wnt11-like signals might specify NC by altering the localization and activity of the serine/threonine polarity kinase PAR-1 (also known as microtubule-associated regulatory kinase or MARK), which itself plays an essential role in NC formation. Consistent with this model, PAR-1 RNA rescues NC markers in embryos in which noncanonical Wnt signaling has been blocked. These experiments identify novel roles for Wnt11R and PAR-1 in NC specification and reveal an unexpected connection between morphogenesis and cell fate.
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Affiliation(s)
- Olga Ossipova
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
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104
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Tevosian SG. Gone without the WNT: a requirement for WNT5A in germ cell migration and testis development. Biol Reprod 2012; 86:1-2. [PMID: 21957192 DOI: 10.1095/biolreprod.111.096461] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Sergei G Tevosian
- College of Veterinary Medicine, University of Florida, Gainesville, USA.
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105
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Daikoku T, Cha J, Sun X, Tranguch S, Xie H, Fujita T, Hirota Y, Lydon J, DeMayo F, Maxson R, Dey SK. Conditional deletion of Msx homeobox genes in the uterus inhibits blastocyst implantation by altering uterine receptivity. Dev Cell 2011; 21:1014-25. [PMID: 22100262 DOI: 10.1016/j.devcel.2011.09.010] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 08/31/2011] [Accepted: 09/20/2011] [Indexed: 12/15/2022]
Abstract
An effective bidirectional communication between an implantation-competent blastocyst and the receptive uterus is a prerequisite for mammalian reproduction. The blastocyst will implant only when this molecular cross-talk is established. Here we show that the muscle segment homeobox gene (Msh) family members Msx1 and Msx2, which are two highly conserved genes critical for epithelial-mesenchymal interactions during development, also play crucial roles in embryo implantation. Loss of Msx1/Msx2 expression correlates with altered uterine luminal epithelial cell polarity and affects E-cadherin/β-catenin complex formation through the control of Wnt5a expression. Application of Wnt5a in vitro compromised blastocyst invasion and trophoblast outgrowth on cultured uterine epithelial cells. The finding that Msx1/Msx2 genes are critical for conferring uterine receptivity and readiness to implantation could have clinical significance, because compromised uterine receptivity is a major cause of pregnancy failure in IVF programs.
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Affiliation(s)
- Takiko Daikoku
- Division of Reproductive Sciences, Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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106
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A switch from canonical to noncanonical Wnt signaling mediates drug resistance in colon cancer cells. PLoS One 2011; 6:e27308. [PMID: 22073312 PMCID: PMC3207861 DOI: 10.1371/journal.pone.0027308] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 10/13/2011] [Indexed: 02/07/2023] Open
Abstract
Butyrate, a fermentation product of fiber in the colon, acts as a histone deacetylase inhibitor (HDACi) and induces apoptosis in colon cancer (CC) cells in vitro. We have reported that the apoptotic effects of butyrate are dependent upon the hyperactivation of the Wnt/beta-catenin pathway. However, prolonged exposure of CC cells to increasing concentrations of butyrate results in the acquisition of resistance to the Wnt/beta-catenin- and apoptosis-inducing effects of this agent, as well as cross-resistance to structurally different HDACis. Here we report that one mechanism whereby HDACi resistance arises is through the increase of beta-catenin-independent (noncanonical) Wnt signaling. Compared to HDACi-sensitive HCT-116 CC cells, HDACi-resistant HCT-R cells exhibit higher levels of AKT/PKB cell survival signaling, which is in part induced by WNT5A and its receptor ROR2. The induction of AKT signaling by HDACis is also detected in other CC cell lines, albeit to a lesser extent than in the drug-resistant HCT-R cells. The observations suggested that the apoptotic effect of butyrate and other HDACis in CC cells can be augmented by inhibitors of pAKT. In agreement with the hypothesis, the combination of MK2206, a pAKT inhibitor, and a HDACi (butyrate or LBH589) induced higher apoptosis in CC cells compared to each agent alone. The exposure to both agents also re-sensitized the HCT-R cells to apoptosis. Finally, the concept of simultaneously inducing canonical Wnt activity and suppressing AKT signaling was translated into a combination of diet-derived agents. Diet-derived pAKT inhibitors (caffeic acid phethyl ester, sulforaphane, dilallyl trisulfide) suppressed the butyrate-induced levels of pAKT, and increased the apoptotic effects of butyrate in both drug-sensitive and drug-resistant CC cells. Our findings can be translated into (a) CC therapy employing combinations of synthetic HDACis and inhibitors of pAKT, as well as (b) CC prevention based upon diets that result in sufficient amounts of butyrate and pAKT inhibitors.
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107
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Update on Wnt signaling in bone cell biology and bone disease. Gene 2011; 492:1-18. [PMID: 22079544 DOI: 10.1016/j.gene.2011.10.044] [Citation(s) in RCA: 288] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 10/13/2011] [Accepted: 10/20/2011] [Indexed: 12/17/2022]
Abstract
For more than a decade, Wnt signaling pathways have been the focus of intense research activity in bone biology laboratories because of their importance in skeletal development, bone mass maintenance, and therapeutic potential for regenerative medicine. It is evident that even subtle alterations in the intensity, amplitude, location, and duration of Wnt signaling pathways affects skeletal development, as well as bone remodeling, regeneration, and repair during a lifespan. Here we review recent advances and discrepancies in how Wnt/Lrp5 signaling regulates osteoblasts and osteocytes, introduce new players in Wnt signaling pathways that have important roles in bone development, discuss emerging areas such as the role of Wnt signaling in osteoclastogenesis, and summarize progress made in translating basic studies to clinical therapeutics and diagnostics centered around inhibiting Wnt pathway antagonists, such as sclerostin, Dkk1 and Sfrp1. Emphasis is placed on the plethora of genetic studies in mouse models and genome wide association studies that reveal the requirement for and crucial roles of Wnt pathway components during skeletal development and disease.
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108
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Fernández-Martos CM, González-Fernández C, González P, Maqueda A, Arenas E, Rodríguez FJ. Differential expression of Wnts after spinal cord contusion injury in adult rats. PLoS One 2011; 6:e27000. [PMID: 22073235 PMCID: PMC3206916 DOI: 10.1371/journal.pone.0027000] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 10/07/2011] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Spinal cord injury is a major cause of disability that has no clinically accepted treatment. Functional decline following spinal cord injury is caused by mechanical damage, secondary cell death, reactive gliosis and a poor regenerative capacity of damaged axons. Wnt proteins are a family of secreted glycoproteins that play key roles in different developmental processes although little is known of the expression patterns and functions of Wnts in the adult central nervous system in normal or diseased states. FINDINGS Using qRT-PCR analysis, we demonstrate that mRNA encoding most Wnt ligands and soluble inhibitors are constitutively expressed in the healthy adult spinal cord. Strikingly, contusion spinal cord injury induced a time-dependent increase in Wnt mRNA expression from 6 hours until 28 days post-injury, and a narrow peak in the expression of soluble Wnt inhibitors between 1 and 3 days post-injury. These results are consistent with the increase in the migration shift, from day 1 to 7, of the intracellular Wnt signalling component, Dishevelled-3. Moreover, after an initial decrease by 1 day, we also found an increase in phosphorylation of the Wnt co-receptor, low-density lipoprotein receptor-related protein 6, and an increase in active β-catenin protein, both of which suffer a dramatic change, from a homogeneous expression pattern in the grey matter to a disorganized injury-induced pattern. CONCLUSIONS Our results suggest a role for Wnts in spinal cord homeostasis and injury. We demonstrate that after injury Wnt signalling is activated via the Wnt/β-catenin and possibly other pathways. These findings provide an important foundation to further address the function of individual Wnt proteins in vivo and the pathophysiology of spinal cord injury.
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Affiliation(s)
| | | | - Pau González
- Laboratorio de Neurología Molecular, Hospital Nacional de Parapléjicos (HNP), Toledo, Spain
| | - Alfredo Maqueda
- Laboratorio de Neurología Molecular, Hospital Nacional de Parapléjicos (HNP), Toledo, Spain
| | - Ernest Arenas
- Molecular Neurobiology Unit, MBB, Karolinska Institute, Stockholm, Sweden
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109
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Galli LM, Burrus LW. Differential palmit(e)oylation of Wnt1 on C93 and S224 residues has overlapping and distinct consequences. PLoS One 2011; 6:e26636. [PMID: 22046319 PMCID: PMC3202554 DOI: 10.1371/journal.pone.0026636] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 09/30/2011] [Indexed: 11/23/2022] Open
Abstract
Though the mechanisms by which cytosolic/intracellular proteins are regulated by the post-translational addition of palmitate adducts is well understood, little is known about how this lipid modification affects secreted ligands, such as Wnts. Here we use mutational analysis to show that differential modification of the two known palmit(e)oylated residues of Wnt1, C93 and S224, has both overlapping and distinct consequences. Though the relative roles of each residue are similar with respect to stability and secretion, two distinct biological assays in L cells show that modification of C93 primarily modulates signaling via a ß-catenin independent pathway while S224 is crucial for ß-catenin dependent signaling. In addition, pharmacological inhibition of Porcupine (Porcn), an upstream regulator of Wnt, by IWP1, specifically inhibited ß-catenin dependent signaling. Consistent with these observations, mapping of amino acids in peptide domains containing C93 and S224 demonstrate that acylation of C93 is likely to be Porcn-independent while that of S224 is Porcn-dependent. Cumulatively, our data strongly suggest that C93 and S224 are modified by distinct enzymes and that the differential modification of these sites has the potential to influence Wnt signaling pathway choice.
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Affiliation(s)
- Lisa M. Galli
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
| | - Laura W. Burrus
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
- * E-mail:
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110
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Boström KI, Rajamannan NM, Towler DA. The regulation of valvular and vascular sclerosis by osteogenic morphogens. Circ Res 2011; 109:564-77. [PMID: 21852555 DOI: 10.1161/circresaha.110.234278] [Citation(s) in RCA: 200] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Vascular calcification increasingly afflicts our aging, dysmetabolic population. Once considered only a passive process of dead and dying cells, vascular calcification has now emerged as a highly regulated form of biomineralization organized by collagenous and elastin extracellular matrices. During skeletal bone formation, paracrine epithelial-mesenchymal and endothelial-mesenchymal interactions control osteochondrocytic differentiation of multipotent mesenchymal progenitor cells. These paracrine osteogenic signals, mediated by potent morphogens of the bone morphogenetic protein and wingless-type MMTV integration site family member (Wnt) superfamilies, are also active in the programming of arterial osteoprogenitor cells during vascular and valve calcification. Inflammatory cytokines, reactive oxygen species, and oxylipids-increased in the clinical settings of atherosclerosis, diabetes, and uremia that promote arteriosclerotic calcification-elicit the ectopic vascular activation of osteogenic morphogens. Specific extracellular and intracellular inhibitors of bone morphogenetic protein-Wnt signaling have been identified as contributing to the regulation of osteogenic mineralization during development and disease. These inhibitory pathways and their regulators afford the development of novel therapeutic strategies to prevent and treat valve and vascular sclerosis.
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Affiliation(s)
- Kristina I Boström
- Department of Medicine, Division of Cardiology, David Geffen School of Medicine at UCLA, 10833 LeConte Ave, Los Angeles, CA 90095, USA.
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111
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Yang J, Baskar S, Kwong KY, Kennedy MG, Wiestner A, Rader C. Therapeutic potential and challenges of targeting receptor tyrosine kinase ROR1 with monoclonal antibodies in B-cell malignancies. PLoS One 2011; 6:e21018. [PMID: 21698301 PMCID: PMC3115963 DOI: 10.1371/journal.pone.0021018] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 05/16/2011] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Based on its selective cell surface expression in chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), receptor tyrosine kinase ROR1 has recently emerged as a promising target for therapeutic monoclonal antibodies (mAbs). To further assess the suitability of ROR1 for targeted therapy of CLL and MCL, a panel of mAbs was generated and its therapeutic utility was investigated. METHODOLOGY AND PRINCIPAL FINDINGS A chimeric rabbit/human Fab library was generated from immunized rabbits and selected by phage display. Chimeric rabbit/human Fab and IgG1 were investigated for their capability to bind to human and mouse ROR1, to mediate antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and internalization, and to agonize or antagonize apoptosis using primary CLL cells from untreated patients as well as MCL cell lines. A panel of mAbs demonstrated high affinity and specificity for a diverse set of epitopes that involve all three extracellular domains of ROR1, are accessible on the cell surface, and mediate internalization. The mAb with the highest affinity and slowest rate of internalization was found to be the only mAb that mediated significant, albeit weak, ADCC. None of the mAbs mediated CDC. Alone, they did not enhance or inhibit apoptosis. CONCLUSIONS AND SIGNIFICANCE Owing to its relatively low cell surface density, ROR1 may be a preferred target for armed rather than naked mAbs. Provided is a panel of fully sequenced and thoroughly characterized anti-ROR1 mAbs suitable for conversion to antibody-drug conjugates, immunotoxins, chimeric antigen receptors, and other armed mAb entities for preclinical and clinical studies.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibody-Dependent Cell Cytotoxicity
- Apoptosis
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/enzymology
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Leukemia, Lymphocytic, Chronic, B-Cell/therapy
- Molecular Sequence Data
- Rabbits
- Receptor Tyrosine Kinase-like Orphan Receptors/chemistry
- Receptor Tyrosine Kinase-like Orphan Receptors/immunology
- Sequence Homology, Amino Acid
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Affiliation(s)
- Jiahui Yang
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sivasubramanian Baskar
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ka Yin Kwong
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michael G. Kennedy
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Adrian Wiestner
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Christoph Rader
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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112
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Kelly JC, Lungchukiet P, Macleod RJ. Extracellular Calcium-Sensing Receptor Inhibition of Intestinal EpithelialTNF Signaling Requires CaSR-Mediated Wnt5a/Ror2 Interaction. Front Physiol 2011; 2:17. [PMID: 21603229 PMCID: PMC3093814 DOI: 10.3389/fphys.2011.00017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 03/31/2011] [Indexed: 01/20/2023] Open
Abstract
Tumor necrosis factor alpha (TNFα) and its receptor TNFR1 play a central role in the development of colitis-associated colon cancer. To understand a role for the extracellular calcium-sensing receptor (CaSR) and its non-canonical Wnt mediators, Wnt5a/Ror2, we used reductionistic systems. We added lipopolysaccharide (LPS) to mouse peritoneal macrophages, RAW264.7 cells, a murine macrophage cell line, and 18Co colonic myofibroblasts, to stimulate TNFα secretion and then activated endogenous CaSR. CaSR activation inhibited TNFα secretion, which in RAW264.7 cells knockdown of CaSR by short-interfering RNA (siRNA) duplex reversed. LPS-stimulated NFκB promoter activity in RAW264.7 cells was inhibited by CaSR activation with Ca2+ or other polyvalent CaSR agonists. Reducing CaSR expression with siRNA duplex prevented this inhibition. Following LPS addition to CaSR–HEK cells or RAW264.7 macrophages, CaSR stimulation deneddylated Cullin1. Wnt5a added to HT-29 cells which overexpressed Ror2 or T84 monolayers treated with 3 mM Ca2+ reduced TNFR1 protein expression ∼70%. TNFα/INFγ addition to high resistance T84 monolayers reduced transepithelial resistance 50% within 4 h. CaSR activation (3 mM Ca2+) together with rhWnt5a (200 ng/ml) prevented this reduction while Wnt3a addition had no effect. LPS-stimulated TNFα secretion from RAW264.7 cells was not effected by rhWnt5a but increased 10-fold by Wnt3a. Together our results suggest that following LPS challenge, CaSR activation will inhibit NFκB activity and reduce TNFα secretion from macrophages and stroma while Wnt5a/Ror2 engagement on intestinal epithelia reduces TNFR1 expression, allowing TNFα signaling to be titrated. Our results also suggest that canonical Wnt signaling may enhance TLR4 stimulation of TNFα secretion from murine macrophages.
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113
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Tyrosine phosphorylation-mediated signaling pathways in dictyostelium. JOURNAL OF SIGNAL TRANSDUCTION 2011; 2011:894351. [PMID: 21776390 PMCID: PMC3135261 DOI: 10.1155/2011/894351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 02/21/2011] [Indexed: 01/21/2023]
Abstract
While studies on metazoan cell proliferation, cell differentiation, and cytokine signaling laid the foundation of the current paradigms of tyrosine kinase signaling, similar studies using lower eukaryotes have provided invaluable insight for the understanding of mammalian pathways, such as Wnt and STAT pathways. Dictyostelium is one of the leading lower eukaryotic model systems where stress-induced cellular responses, Wnt-like pathways, and STAT-mediated pathways are well investigated. These Dictyostelium pathways will be reviewed together with their mammalian counterparts to facilitate the comparative understanding of these variant and noncanonical pathways.
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114
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Shafer B, Onishi K, Lo C, Colakoglu G, Zou Y. Vangl2 promotes Wnt/planar cell polarity-like signaling by antagonizing Dvl1-mediated feedback inhibition in growth cone guidance. Dev Cell 2011; 20:177-91. [PMID: 21316586 DOI: 10.1016/j.devcel.2011.01.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 11/04/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
Abstract
Although a growing body of evidence supports that Wnt-Frizzled signaling controls axon guidance from vertebrates to worms, whether and how this is mediated by planar cell polarity (PCP) signaling remain elusive. We show here that the core PCP components are required for Wnt5a-stimulated outgrowth and anterior-posterior guidance of commissural axons. Dishevelled1 can inhibit PCP signaling by increasing hyperphosphorylation of Frizzled3 and preventing its internalization. Vangl2 antagonizes that by reducing Frizzled3 phosphorylation and promotes its internalization. In commissural axon growth cones, Vangl2 is predominantly localized on the plasma membrane and is highly enriched on the tips of the filopodia as well as in patches of membrane where new filopodia emerge. Taken together, we propose that the antagonistic functions of Vangl2 and Dvl1 (over Frizzled3 hyperphosphorylation and endocytosis) allow sharpening of PCP signaling locally on the tips of the filopodia to sense directional cues, Wnts, eventually causing turning of growth cones.
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Affiliation(s)
- Beth Shafer
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
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115
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Liebl FLW, McKeown C, Yao Y, Hing HK. Mutations in Wnt2 alter presynaptic motor neuron morphology and presynaptic protein localization at the Drosophila neuromuscular junction. PLoS One 2010; 5:e12778. [PMID: 20856675 PMCID: PMC2939895 DOI: 10.1371/journal.pone.0012778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Accepted: 08/24/2010] [Indexed: 01/02/2023] Open
Abstract
Wnt proteins are secreted proteins involved in a number of developmental processes including neural development and synaptogenesis. We sought to determine the role of the Drosophila Wnt7b ortholog, Wnt2, using the neuromuscular junction (NMJ). Mutations in wnt2 produce an increase in the number of presynaptic branches and a reduction in immunolabeling of the active zone proteins, Bruchpilot and synaptobrevin, at the NMJ. There was no change, however, in immunolabeling for the presynaptic proteins cysteine-string protein (CSP) and synaptotagmin, nor the postsynaptic proteins GluRIIA and DLG at the NMJ. Consistent with the presynaptic defects, wnt2 mutants exhibit approximately a 50% reduction in evoked excitatory junctional currents. Rescue, RNAi, and tissue-specific qRT-PCR experiments indicate that Wnt2 is expressed by the postsynaptic cell where it may serve as a retrograde signal that regulates presynaptic morphology and the localization of presynaptic proteins.
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Affiliation(s)
- Faith L W Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America.
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116
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Sonderegger S, Pollheimer J, Knöfler M. Wnt signalling in implantation, decidualisation and placental differentiation--review. Placenta 2010; 31:839-47. [PMID: 20716463 DOI: 10.1016/j.placenta.2010.07.011] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 07/20/2010] [Accepted: 07/21/2010] [Indexed: 12/19/2022]
Abstract
The family of secreted Wingless ligands plays major roles in embryonic development, stem cell maintenance, differentiation and tissue homeostasis. Accumulating evidence suggests that the canonical Wnt pathway involving nuclear recruitment of β-catenin and activation of Wnt-dependent transcription factors is also critically involved in development and differentiation of the diverse reproductive tissues. Here, we summarise our present knowledge about expression, regulation and function of Wnt ligands and their frizzled receptors in murine and human endometrial and placental cell types. In mice, Wnt signalling promotes early trophoblast lineage development, blastocyst activation, implantation and chorion-allantois fusion. Moreover, different Wnt ligands play essential roles in the development of the murine uterine tract, in cycling endometrial cells and during decidualisation. In humans, estrogen-dependent endometrial cell proliferation, decidualisation, trophoblast attachment and invasion were shown to be controlled by the particular signalling pathway. Failures in Wnt signalling are associated with infertility, endometriosis, endometrial cancer and gestational diseases such as complete mole placentae and choriocarcinomas. However, our present knowledge is still scarce due to the complexity of the Wnt network involving numerous ligands, receptors and non-canonical pathways. Hence, much remains to be learned about the role of different Wnt signalling cascades in reproductive cell types and their changes under pathological conditions.
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Affiliation(s)
- S Sonderegger
- Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
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Lara E, Calvanese V, Huidobro C, Fernández AF, Moncada-Pazos A, Obaya AJ, Aguilera O, González-Sancho JM, Sánchez L, Astudillo A, Muñoz A, López-Otín C, Esteller M, Fraga MF. Epigenetic repression of ROR2 has a Wnt-mediated, pro-tumourigenic role in colon cancer. Mol Cancer 2010; 9:170. [PMID: 20591152 PMCID: PMC2903502 DOI: 10.1186/1476-4598-9-170] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 06/30/2010] [Indexed: 01/19/2023] Open
Abstract
Background Wnt factors control cell differentiation through semi-independent molecular cascades known as the β-catenin-dependent (canonical) and -independent (non-canonical) Wnt signalling pathways. Genetic and epigenetic alteration of components of the canonical Wnt signalling pathway is one of the primary mechanisms underlying colon cancer. Despite increasing evidence of the role of the non-canonical pathways in tumourigenesis, however, the underlying molecular mechanisms are poorly understood. Results Here we report that the receptor tyrosine kinase-like orphan receptor 2 (ROR2), a transmembrane receptor for Wnt factors that activates non-canonical pathways, is frequently repressed by aberrant promoter hypermethylation in human colon cancer cell lines and primary tumours. By restoring ROR2 activity in colon cancer cells harbouring ROR2 promoter hypermethylation, we show that the role of ROR2 in colon cancer cells is mediated, at least in part, by canonical Wnt and that its epigenetic-dependent loss can be pro-tumourigenic. Conclusions Our data show the importance of epigenetic alterations of ROR2 in colon cancer, highlighting the close interconnection between canonical and non-canonical Wnt signalling pathways in this type of tumour.
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Affiliation(s)
- Ester Lara
- Department of Immunology and Oncology, National Center for Biotechnology, CNB-CSIC, Cantoblanco, Madrid E-28049, Spain
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When pathways collide: collaboration and connivance among signalling proteins in development. Nat Rev Mol Cell Biol 2010; 11:404-13. [PMID: 20461097 DOI: 10.1038/nrm2902] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Signal transduction pathways interact at various levels to define tissue morphology, size and differentiation during development. Understanding the mechanisms by which these pathways collude has been greatly enhanced by recent insights into how shared components are independently regulated and how the activity of one system is contextualized by others. Traditionally, it has been assumed that the components of signalling pathways show pathway fidelity and act with a high degree of autonomy. However, as illustrated by the Wnt and Hippo pathways, there is increasing evidence that components are often shared between multiple pathways and other components talk to each other through multiple mechanisms.
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Ror2/Frizzled complex mediates Wnt5a-induced AP-1 activation by regulating Dishevelled polymerization. Mol Cell Biol 2010; 30:3610-9. [PMID: 20457807 DOI: 10.1128/mcb.00177-10] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The receptor tyrosine kinase Ror2 acts as a receptor or coreceptor for Wnt5a to mediate Wnt5a-induced activation of the Wnt/JNK pathway and inhibition of the beta-catenin-dependent canonical Wnt pathway. However, little is known about how Ror2 cooperates with another receptor component(s) to mediate Wnt5a signaling. We show here that Ror2 regulates Wnt5a-induced polymerization of Dishevelled (Dvl) and that this Ror2-mediated regulation of Dvl is independent of the cytoplasmic region of Ror2. Ror2 can associate with Frizzled7 (Fz7) via its extracellular cysteine-rich domain to form a receptor complex that is required for the regulation of Dvl and activation of the AP-1 promoter after Wnt5a stimulation. Suppressed expression of Fz7 indeed results in the inhibition of Wnt5a-induced polymerization of Dvl and AP-1 activation. Interestingly, both the DIX and the DEP domains of Dvl are indispensable for Dvl polymerization and subsequent AP-1 activation after Wnt5a stimulation. We further show that polymerized Dvl is colocalized with Rac1 and that suppressed expression of Rac1 inhibits Wnt5a-induced AP-1 activation. Collectively, our results indicate that Ror2/Fz receptor complex plays an important role in the Wnt5a/Rac1/AP-1 pathway by regulating the polymerization of Dvl.
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Abstract
At the cellular level, the biological processes of cell proliferation, growth arrest, differentiation and apoptosis are all tightly coupled to appropriate alterations in metabolic status. In the case of cell proliferation, this requires redirecting metabolic pathways to provide the fuel and basic components for new cells. Ultimately, the successful co-ordination of cell-specific biology with cellular metabolism underscores multicellular processes as diverse as embryonic development, adult tissue remodelling and cancer cell biology. The Wnt signalling network has been implicated in all of these areas. While each of the Wnt-dependent signalling pathways are being individually delineated in a range of experimental systems, our understanding of how they integrate and regulate cellular metabolism is still in its infancy. In the present review we reassess the roles of Wnt signalling in functionally linking cellular metabolism to tissue development and function.
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Affiliation(s)
- Jaswinder K Sethi
- Department of Clinical Biochemistry, University of Cambridge Metabolic Research Laboratories, Level 4, Institute of Metabolic Science, Box 289, Addenbrooke's Hospital, Cambridge CB20QQ, U.K.
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