151
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Shastry BS. Genetics of familial exudative vitreoretinopathy and its implications for management. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.40] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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152
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Maruotti N, Corrado A, Neve A, Cantatore FP. Systemic effects of Wnt signaling. J Cell Physiol 2013; 228:1428-32. [PMID: 23359342 DOI: 10.1002/jcp.24326] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/14/2013] [Indexed: 12/15/2022]
Abstract
Wnt signaling plays a key role in several physiological and pathological aspects. Even if Wnt signal was first described more than 20 years ago, its role in systemic effects, such as angiogenesis and vascular disorders, bone biology, autoimmune diseases, neurological diseases, and neoplastic disorders, was only recently emerged through the use of animal and in vitro models. Moreover, Wnt signaling inhibitors, such as DKK-1, may be advantageously considered targets for the treatment of several diseases, including osteoporosis, vascular diseases, inflammatory diseases, neurological diseases, and cancer. Nevertheless, further studies are required to provide a complete understanding of this complex signaling pathway, and especially of its role in human diseases, considering the possible advantageous effects of Wnt signaling inhibitors on the progression of disease conditions.
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Affiliation(s)
- Nicola Maruotti
- Department of Rheumatology, University of Foggia Medical School, Foggia, Italy
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153
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Deletion of LRP5 in VLDLR knockout mice inhibits retinal neovascularization. PLoS One 2013; 8:e75186. [PMID: 24058663 PMCID: PMC3772893 DOI: 10.1371/journal.pone.0075186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 08/12/2013] [Indexed: 11/19/2022] Open
Abstract
The development and maintenance of retinal vasculature require a precise balance between pro-angiogenic and anti-angiogenic factors. However, mechanisms underlying normal homeostasis of retinal vasculature and pathological changes of disrupted retinal vessel development are not fully understood. Recent studies of the low-density lipoprotein receptor-related protein 5 (LRP5) and the very low-density lipoprotein receptor (VLDLR) mutant mice indicate that LRP5 mediates a pro-angiogenic signal while VLDLR mediates an anti-angiogenic signal in retinal vasculature. Mice with a loss of LRP5 display underdeveloped intraretinal vasculature associated with endothelial cell (EC) clustering and failed EC migration into deep retinal layers. In contrast, VLDLR knockout mice show overgrown intraretinal vasculature and subretinal neovascularization. To understand the mechanisms for the opposite retinal vascular abnormalities between LRP5 and VLDLR mutant mice and to test how a loss of LRP5 perturbs subretinal neovascularization caused by a loss of VLDLR, we have generated and characterized the retinal vasculature in LRP5/VLDLR double knockout (DKO) mice. Our data show that DKO mice develop substantial EC clustering without subretinal neovascularization. The absence of subretinal neovascularization in DKO mice is associated with inhibited migration of ECs into the photoreceptor cell layer. In addition, the transcription level of Slc38a5, which encodes a Müller cell specific glutamine transporter, is significantly reduced in DKO mice, similar to previously reported changes in LRP5 single knockout mice. Thus, LRP5 signaling is a prerequisite for neovascularization in VLDLR knockout mice. LRP5 may be an effective target for inhibiting intraretinal neovascularization.
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154
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D'Agostino M, Lemma V, Chesi G, Stornaiuolo M, Cannata Serio M, D'Ambrosio C, Scaloni A, Polishchuk R, Bonatti S. The cytosolic chaperone α-crystallin B rescues folding and compartmentalization of misfolded multispan transmembrane proteins. J Cell Sci 2013; 126:4160-72. [PMID: 23843626 DOI: 10.1242/jcs.125443] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The α-crystallin B chain (CRYAB or HspB5) is a cytosolic chaperone belonging to the small heat shock protein family, which is known to help in the folding of cytosolic proteins. Here we show that CRYAB binds the mutant form of at least two multispan transmembrane proteins (TMPs), exerting an anti-aggregation activity. It rescues the folding of mutant Frizzled4, which is responsible for a rare autosomal dominant form of familial exudative vitreoretinopathy (Fz4-FEVR), and the mutant ATP7B Cu transporter (ATP7B-H1069Q) associated with a common form of Wilson's disease. In the case of Fz4-FEVR, CRYAB prevents the formation of inter-chain disulfide bridges between the lumenal ectodomains of the aggregated mutant chains, which enables correct folding and promotes appropriate compartmentalization on the plasma membrane. ATP7B-H1069Q, with help from CRYAB, folds into the proper conformation, moves to the Golgi complex, and responds to copper overload in the same manner as wild-type ATP7B. These findings strongly suggest that CRYAB plays a pivotal role, previously undetected, in the folding of multispan TMPs and, from the cytosol, is able to orchestrate folding events that take place in the lumen of the ER. Our results contribute to the explanation of the complex scenario behind multispan TMP folding; additionally, they serve to expose interesting avenues for novel therapeutic approaches.
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Affiliation(s)
- Massimo D'Agostino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy
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155
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Savarese M, Spinelli E, Gandolfo F, Lemma V, Di Fruscio G, Padoan R, Morescalchi F, D'Agostino M, Savoldi G, Semeraro F, Nigro V, Bonatti S. Familial exudative vitreoretinopathy caused by a homozygous mutation in TSPAN12 in a cystic fibrosis infant. Ophthalmic Genet 2013; 35:184-6. [PMID: 23834558 DOI: 10.3109/13816810.2013.811270] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Familial exudative vitreoretinopathy (FEVR) is a genetic disease affecting the vascularization of the peripheral retina. The clinical manifestations are very heterogeneous, ranging from mildly affected patients, who could present no visual defects, to severe conditions which can also cause complete blindness at birth or in the first decade. FEVR can be inherited in all the three genetic forms: dominant, recessive and X-linked. To date, four genes have been associated with the condition: TSPAN12. NDP. FDZ4 and LRP5. Interestingly, mutations in TSPAN12 have been considered causative of both a dominant and recessive inheritance and a FEVR phenotype sensitive to the number of TSPAN12 mutations has been supposed. Here we describe a case of a female infant affected by cystic fibrosis and by a severe form of exudative vitreoretinopathy. In particular, we have detected the homozygous missense mutation c.668 T > C in TSPAN12. Neither of the heterozygous parents has ocular manifestations of the disease, suggesting a classic recessive mendelian pattern of inheritance.
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Affiliation(s)
- Marco Savarese
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples , Italy
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156
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Block GJ, Narayanan D, Amell AM, Petek LM, Davidson KC, Bird TD, Tawil R, Moon RT, Miller DG. Wnt/β-catenin signaling suppresses DUX4 expression and prevents apoptosis of FSHD muscle cells. Hum Mol Genet 2013; 22:4661-72. [PMID: 23821646 DOI: 10.1093/hmg/ddt314] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Facioscapulohumeral muscular dystrophy is a dominantly inherited myopathy associated with chromatin relaxation of the D4Z4 macrosatellite array on chromosome 4. DUX4 is encoded within each unit of the D4Z4 array where it is normally transcriptionally silenced and packaged as constitutive heterochromatin. Truncation of the array to less than 11 D4Z4 units (FSHD1) or mutations in SMCHD1 (FSHD2) results in chromatin relaxation and a small percentage of cultured myoblasts from these individuals exhibit infrequent bursts of DUX4 expression. There are no cellular or animal models to determine the trigger of the DUX4 producing transcriptional bursts and there has been a failure to date to detect the protein in significant numbers of cells from FSHD-affected individuals. Here, we demonstrate for the first time that myotubes generated from FSHD patients express sufficient amounts of DUX4 to undergo DUX4-dependent apoptosis. We show that activation of the Wnt/β-catenin signaling pathway suppresses DUX4 transcription in FSHD1 and FSHD2 myotubes and can rescue DUX4-mediated myotube apoptosis. In addition, reduction of mRNA transcripts from Wnt pathway genes β-catenin, Wnt3A and Wnt9B results in DUX4 activation. We propose that Wnt/β-catenin signaling is important for transcriptional repression of DUX4 and identify a novel group of therapeutic targets for the treatment of FSHD.
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157
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Chitalia V, Shivanna S, Martorell J, Meyer R, Edelman E, Rahimi N. c-Cbl, a ubiquitin E3 ligase that targets active β-catenin: a novel layer of Wnt signaling regulation. J Biol Chem 2013; 288:23505-17. [PMID: 23744067 DOI: 10.1074/jbc.m113.473801] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulation of transcriptionally active nuclear β-catenin during the Wnt-on phase is crucial to ensure controlled induction of Wnt target genes. Several ubiquitin E3 ligases are known to regulate cytosolic β-catenin during the Wnt-off phase, but little is known about the fate of active nuclear β-catenin in the Wnt-on phase. We now describe ubiquitination of active β-catenin in the Wnt-on phase by a RING finger ubiquitin E3 ligase, Casitas B-lineage lymphoma (c-Cbl) in endothelial cells. c-Cbl binds preferentially to nuclearly active β-catenin in the Wnt-on phase via the armadillo repeat region. Wild-type c-Cbl suppresses and E3 ligase-deficient c-Cbl-70Z increases Wnt signaling. Wnt induces nuclear translocation of c-Cbl where it ubiquitinates nuclear β-catenin. Deletion of the c-Cbl UBA domain abrogates its dimerization, binding to β-catenin, Wnt-induced c-Cbl nuclear translocation, and ubiquitination of nuclear β-catenin. c-Cbl activity inhibits pro-angiogenic Wnt targets IL-8 and VEGF levels and angiogenesis in a β-catenin-dependent manner. This study defines for the first time c-Cbl as a ubiquitin E3 ligase that targets nuclearly active β-catenin in the Wnt-on phase and uncovers a novel layer of regulation of Wnt signaling.
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Affiliation(s)
- Vipul Chitalia
- Renal Section, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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158
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Caruso N, Herberth B, Bartoli M, Puppo F, Dumonceaux J, Zimmermann A, Denadai S, Lebossé M, Roche S, Geng L, Magdinier F, Attarian S, Bernard R, Maina F, Levy N, Helmbacher F. Deregulation of the protocadherin gene FAT1 alters muscle shapes: implications for the pathogenesis of facioscapulohumeral dystrophy. PLoS Genet 2013; 9:e1003550. [PMID: 23785297 PMCID: PMC3681729 DOI: 10.1371/journal.pgen.1003550] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 04/23/2013] [Indexed: 01/01/2023] Open
Abstract
Generation of skeletal muscles with forms adapted to their function is essential for normal movement. Muscle shape is patterned by the coordinated polarity of collectively migrating myoblasts. Constitutive inactivation of the protocadherin gene Fat1 uncoupled individual myoblast polarity within chains, altering the shape of selective groups of muscles in the shoulder and face. These shape abnormalities were followed by early onset regionalised muscle defects in adult Fat1-deficient mice. Tissue-specific ablation of Fat1 driven by Pax3-cre reproduced muscle shape defects in limb but not face muscles, indicating a cell-autonomous contribution of Fat1 in migrating muscle precursors. Strikingly, the topography of muscle abnormalities caused by Fat1 loss-of-function resembles that of human patients with facioscapulohumeral dystrophy (FSHD). FAT1 lies near the critical locus involved in causing FSHD, and Fat1 mutant mice also show retinal vasculopathy, mimicking another symptom of FSHD, and showed abnormal inner ear patterning, predictive of deafness, reminiscent of another burden of FSHD. Muscle-specific reduction of FAT1 expression and promoter silencing was observed in foetal FSHD1 cases. CGH array-based studies identified deletion polymorphisms within a putative regulatory enhancer of FAT1, predictive of tissue-specific depletion of FAT1 expression, which preferentially segregate with FSHD. Our study identifies FAT1 as a critical determinant of muscle form, misregulation of which associates with FSHD.
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Affiliation(s)
- Nathalie Caruso
- Aix-Marseille Université, CNRS, IBDML UMR 7288, Parc Scientifique de Luminy, Case 907, Marseille, France
| | - Balàzs Herberth
- Aix-Marseille Université, CNRS, IBDML UMR 7288, Parc Scientifique de Luminy, Case 907, Marseille, France
| | - Marc Bartoli
- Aix-Marseille Université, Faculté de Médecine de la Timone, INSERM UMR 910, Marseille, France
| | - Francesca Puppo
- Aix-Marseille Université, Faculté de Médecine de la Timone, INSERM UMR 910, Marseille, France
| | - Julie Dumonceaux
- INSERM U974, UMR 7215 CNRS, Institut de Myologie, UM 76 Université Pierre et Marie Curie, Paris, France
| | - Angela Zimmermann
- Aix-Marseille Université, CNRS, IBDML UMR 7288, Parc Scientifique de Luminy, Case 907, Marseille, France
| | - Simon Denadai
- Aix-Marseille Université, CNRS, IBDML UMR 7288, Parc Scientifique de Luminy, Case 907, Marseille, France
| | - Marie Lebossé
- Aix-Marseille Université, CNRS, IBDML UMR 7288, Parc Scientifique de Luminy, Case 907, Marseille, France
| | - Stephane Roche
- Aix-Marseille Université, Faculté de Médecine de la Timone, INSERM UMR 910, Marseille, France
| | - Linda Geng
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Frederique Magdinier
- Aix-Marseille Université, Faculté de Médecine de la Timone, INSERM UMR 910, Marseille, France
| | - Shahram Attarian
- Aix-Marseille Université, Faculté de Médecine de la Timone, INSERM UMR 910, Marseille, France
- AP-HM, Neurologie, maladies neuro-musculaires, Hôpital de la Timone, Marseille, France
| | - Rafaelle Bernard
- Aix-Marseille Université, Faculté de Médecine de la Timone, INSERM UMR 910, Marseille, France
- AP-HM, Département de Génétique Médicale, Hôpital d'enfants Timone, Marseille, France
| | - Flavio Maina
- Aix-Marseille Université, CNRS, IBDML UMR 7288, Parc Scientifique de Luminy, Case 907, Marseille, France
| | - Nicolas Levy
- Aix-Marseille Université, Faculté de Médecine de la Timone, INSERM UMR 910, Marseille, France
- AP-HM, Département de Génétique Médicale, Hôpital d'enfants Timone, Marseille, France
| | - Françoise Helmbacher
- Aix-Marseille Université, CNRS, IBDML UMR 7288, Parc Scientifique de Luminy, Case 907, Marseille, France
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159
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Gandhi JK, Tollefson TT, Telander DG. Falciform macular folds and chromosome 22q11.2: evidence in support of a locus for familial exudative vitreoretinopathy (FEVR). Ophthalmic Genet 2013; 35:112-6. [PMID: 23521024 DOI: 10.3109/13816810.2013.779382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Familial exudative vitreoretinopathy (FEVR) is a genetic disease caused by abnormal retinal vascular development. New additional genetic loci for FEVR have recently been identified. Microduplication of 22q11.2 has been reported with a heterogeneous phenotype and microdeletion of 22q11.2 has been associated with FEVR. We describe a case of a girl with microduplication of 22q11.2 and falciform macular folds. MATERIALS AND METHODS The infant and first-degree relatives were examined. A dilated fundus examination was performed. Genetic screening was done by chromosomal microarray analysis and confirmed by fluorescent in situ hybridization (FISH). RESULTS Bilateral macular folds were found with temporal fibrosis in the proband. A chromosomal microarray revealed a 2.21 Mb microduplication of the 22q11.2 region. CONCLUSION This is the first report to associate microduplication of 22q11.2 with macular folds, supporting the potential for a FEVR locus on chromosome 22q11.2. We encourage full ophthalmological examination for patients with microduplication of 22q11.2 to identify ocular associations.
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160
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Cruciat CM, Niehrs C. Secreted and transmembrane wnt inhibitors and activators. Cold Spring Harb Perspect Biol 2013; 5:a015081. [PMID: 23085770 DOI: 10.1101/cshperspect.a015081] [Citation(s) in RCA: 463] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
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.
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Affiliation(s)
- Cristina-Maria Cruciat
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, DKFZ, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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161
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Lippmann ES, Azarin SM, Kay JE, Nessler RA, Wilson HK, Al-Ahmad A, Palecek SP, Shusta EV. Derivation of blood-brain barrier endothelial cells from human pluripotent stem cells. Nat Biotechnol 2013; 30:783-91. [PMID: 22729031 PMCID: PMC3467331 DOI: 10.1038/nbt.2247] [Citation(s) in RCA: 530] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 04/30/2012] [Indexed: 11/09/2022]
Abstract
The blood-brain barrier (BBB) is crucial to the health of the brain and is often compromised in neurological disease. Moreover, because of its barrier properties, this endothelial interface restricts uptake of neurotherapeutics. Thus, a renewable source of human BBB endothelium could spur brain research and pharmaceutical development. Here we show that endothelial cells derived from human pluripotent stem cells (hPSCs) acquire BBB properties when co-differentiated with neural cells that provide relevant cues, including those involved in Wnt/β-catenin signaling. The resulting endothelial cells have many BBB attributes, including well-organized tight junctions, appropriate expression of nutrient transporters and polarized efflux transporter activity. Notably, they respond to astrocytes, acquiring substantial barrier properties as measured by transendothelial electrical resistance (1,450 ± 140 Ω cm2), and they possess molecular permeability that correlates well with in vivo rodent blood-brain transfer coefficients.
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Affiliation(s)
- Ethan S Lippmann
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, Wisconsin, USA
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162
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Abstract
Since the initial discovery of the oncogenic activity of WNT1 in mouse mammary glands, our appreciation for the complex roles for WNT signalling pathways in cancer has increased dramatically. WNTs and their downstream effectors regulate various processes that are important for cancer progression, including tumour initiation, tumour growth, cell senescence, cell death, differentiation and metastasis. Although WNT signalling pathways have been difficult to target, improved drug-discovery platforms and new technologies have facilitated the discovery of agents that can alter WNT signalling in preclinical models, thus setting the stage for clinical trials in humans.
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Affiliation(s)
- Jamie N Anastas
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington 98109, USA
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163
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Igota S, Tosa M, Murakami M, Egawa S, Shimizu H, Hyakusoku H, Ghazizadeh M. Identification and characterization of Wnt signaling pathway in keloid pathogenesis. Int J Med Sci 2013; 10:344-54. [PMID: 23471552 PMCID: PMC3590592 DOI: 10.7150/ijms.5349] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 02/10/2013] [Indexed: 12/22/2022] Open
Abstract
Keloid is characterized by fibroblastic cell proliferation and abundant collagen synthesis. Numerous studies have shown that the Wingless type (Wnt) signaling pathways play key roles in various cellular functions including proliferation, differentiation, survival, apoptosis and migration. The aim of this study was to clarify the role of Wnt signaling pathway in keloid pathogenesis. Primary fibroblast cultures and tissue samples from keloid and normal appearing dermis were used. The expression of Wnt family members, frizzled (FZD)4 receptor, receptor tyrosine kinase-like orphan receptor (ROR)2 and the Wnt signaling downstream targets, glycogen synthase kinase (GSK)3-β and β-catenin were assessed using semi-quantitative RT-PCR, Western blot, or immunohistochemical methods. Of the Wnt family members, Wnt5a mRNA and protein levels were elevated in keloid fibroblasts (KF) as compared to normal fibroblasts (NF). A higher expression of β-catenin protein was also found in KF. No detectable levels of FZD4 receptor and ROR2 proteins were observed in both NF and KF. Functional analysis showed that treatment of NF and KF with recombinant Wnt5a peptide resulted in an increase in protein levels of total β-catenin and phosphorylated β-catenin at Ser33/37/Thr 41 but no significant change in phosphorylated β-catenin at Ser45/Thr 41 positions. In addition, the expression of total GSK3-β protein was not affected but its phosphorylated/inactivated form was increased in NF and KF. Our findings highlight a potential role for a Wnt/β-catenin canonical signaling pathway triggered by Wnt5a in keloid pathogenesis thereby providing a new molecular target for therapeutic modulations.
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Affiliation(s)
- Shinichi Igota
- Department of Molecular Pathology, Institute of Gerontology, Nippon Medical School, Kawasaki, Japan
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164
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MacDonald BT, He X. Frizzled and LRP5/6 receptors for Wnt/β-catenin signaling. Cold Spring Harb Perspect Biol 2012; 4:4/12/a007880. [PMID: 23209147 DOI: 10.1101/cshperspect.a007880] [Citation(s) in RCA: 421] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Frizzled and LRP5/6 are Wnt receptors that upon activation lead to stabilization of cytoplasmic β-catenin. In this study, we review the current knowledge of these two families of receptors, including their structures and interactions with Wnt proteins, and signaling mechanisms from receptor activation to the engagement of intracellular partners Dishevelled and Axin, and finally to the inhibition of β-catenin phosphorylation and ensuing β-catenin stabilization.
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Affiliation(s)
- Bryan T MacDonald
- The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
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165
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Gregory-Evans CY, Wallace VA, Gregory-Evans K. Gene networks: dissecting pathways in retinal development and disease. Prog Retin Eye Res 2012; 33:40-66. [PMID: 23128416 DOI: 10.1016/j.preteyeres.2012.10.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 01/21/2023]
Abstract
During retinal neurogenesis, diverse cellular subtypes originate from multipotent neural progenitors in a spatiotemporal order leading to a highly specialized laminar structure combined with a distinct mosaic architecture. This is driven by the combinatorial action of transcription factors and signaling molecules which specify cell fate and differentiation. The emerging approach of gene network analysis has allowed a better understanding of the functional relationships between genes expressed in the developing retina. For instance, these gene networks have identified transcriptional hubs that have revealed potential targets and pathways for the development of therapeutic options for retinal diseases. Much of the current knowledge has been informed by targeted gene deletion experiments and gain-of-functional analysis. In this review we will provide an update on retinal development gene networks and address the wider implications for future disease therapeutics.
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Affiliation(s)
- Cheryl Y Gregory-Evans
- Department of Ophthalmology, University of British Columbia, Vancouver, BC V5Z 3N9, Canada.
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166
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Zimmerman ZF, Moon RT, Chien AJ. Targeting Wnt pathways in disease. Cold Spring Harb Perspect Biol 2012; 4:cshperspect.a008086. [PMID: 23001988 DOI: 10.1101/cshperspect.a008086] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
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.
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Affiliation(s)
- Zachary F Zimmerman
- Department of Medicine, Division of Oncology, University of Washington, Seattle, 98195, USA
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167
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Fuhrmann S. Wnt signaling in eye organogenesis. Organogenesis 2012; 4:60-7. [PMID: 19122781 DOI: 10.4161/org.4.2.5850] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 03/06/2008] [Indexed: 11/19/2022] Open
Abstract
The vertebrate eye consists of multiple tissues with distinct embryonic origins. To ensure formation of the eye as a functional organ, development of ocular tissues must be precisely coordinated. Besides intrinsic regulators, several extracellular pathways have been shown to participate in controlling critical steps during eye development. Many components of Wnt/Frizzled signaling pathways are expressed in developing ocular tissues, and substantial progress has been made in the past few years in understanding their function during vertebrate eye development. Here, I summarize recent work using functional experiments to elucidate the roles of Wnt/Frizzled pathways during development of ocular tissues in different vertebrates.
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Affiliation(s)
- Sabine Fuhrmann
- Department of Ophthalmology and Visual Sciences; John A. Moran Eye Center; University of Utah; Salt Lake City, Utah USA
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168
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Newman AC, Hughes CCW. Macrophages and angiogenesis: a role for Wnt signaling. Vasc Cell 2012; 4:13. [PMID: 22938389 PMCID: PMC3479425 DOI: 10.1186/2045-824x-4-13] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 07/13/2012] [Indexed: 12/15/2022] Open
Abstract
Macrophages regulate many developmental and pathological processes in both embryonic and adult tissues, and recent studies have shown a significant role in angiogenesis. Similarly, Wnt signaling is fundamental to tissue morphogenesis and also has a role in vascular development. In this review, we summarize recent advances in the field of macrophage-regulated angiogenesis, with a focus on the role of macrophage-derived Wnt ligands. We review data that provide both direct and indirect evidence for macrophage-derived Wnt regulation of physiologic and pathologic angiogenesis. Finally, we propose that Wnt signaling plays a central role in differentiation of tumor associated and wound infiltrating macrophages to a proangiogenic phenotype.
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Affiliation(s)
- Andrew C Newman
- The Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA, 92697, USA.
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169
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Abstract
The WNT signal transduction cascade controls myriad biological phenomena throughout development and adult life of all animals. In parallel, aberrant Wnt signaling underlies a wide range of pathologies in humans. In this Review, we provide an update of the core Wnt/β-catenin signaling pathway, discuss how its various components contribute to disease, and pose outstanding questions to be addressed in the future.
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Affiliation(s)
- Hans Clevers
- Hubrecht Institute, KNAW and University Medical Center Utrecht, The Netherlands.
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170
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Choi HJ, Park H, Lee HW, Kwon YG. The Wnt pathway and the roles for its antagonists, DKKS, in angiogenesis. IUBMB Life 2012; 64:724-31. [PMID: 22807036 DOI: 10.1002/iub.1062] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 05/06/2012] [Accepted: 05/24/2012] [Indexed: 11/07/2022]
Abstract
The Wnt signaling pathway is involved in a wide range of developmental and physiological processes, such as cell fate specification, tissue morphogenesis, and homeostasis. Thus, its dysregulation has been found in multiple diseases, including some cardiovascular disorders. The loss or gain of function of Wnt pathway components results in abnormal vascular development and angiogenesis. Further study has revealed that Wnt signaling in endothelial cells appears to contribute to vascular morphogenesis and endothelial cell specification. Owing to the significance of Wnt signaling in angiogenesis, Wnt antagonists have been considered potential treatments for neovascular disorders. In line with this, members of the Dkk protein family (Dkks), well-known Wnt antagonists, have been recently found to regulate angiogenesis. This review summarizes our present knowledge of the roles of Wnt signaling and Wnt antagonists, particularly Dkks, in angiogenic regulation and explores the therapeutic potential of Wnt antagonists.
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Affiliation(s)
- Hyun-Jung Choi
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
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171
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Cai H, Fields MA, Hoshino R, Priore LVD. Effects of aging and anatomic location on gene expression in human retina. Front Aging Neurosci 2012; 4:8. [PMID: 22666212 PMCID: PMC3364488 DOI: 10.3389/fnagi.2012.00008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 05/10/2012] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVE To determine the effects of age and topographic location on gene expression in human neural retina. METHODS Macular and peripheral neural retina RNA was isolated from human donor eyes for DNA microarray and quantitative RT-PCR analyses. RESULTS Total RNA integrity from human donors was preserved. Hierarchical clustering analysis demonstrates that the gene expression profiles of young, old, macula, and peripheral retina cluster into four distinct groups. Genes which are highly expressed in macular, peripheral, young, or old retina were identified, including inhibitors of Wnt Signaling Pathway (DKK1, FZD10, and SFRP2) which are preferably expressed in the periphery. CONCLUSION The transcriptome of the human retina is affected by age and topographic location. Wnt pathway inhibitors in the periphery may maintain peripheral retinal cells in an undifferentiated state. Understanding the effects of age and topographic location on gene expression may lead to the development of new therapeutic interventions for age-related eye diseases.
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Affiliation(s)
- Hui Cai
- Department of Ophthalmology, Harkness Eye Institute, Columbia University, New York NY, USA
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172
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Three decades of Wnts: a personal perspective on how a scientific field developed. EMBO J 2012; 31:2670-84. [PMID: 22617420 DOI: 10.1038/emboj.2012.146] [Citation(s) in RCA: 308] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 04/24/2012] [Indexed: 12/13/2022] Open
Abstract
Wnt genes and components of Wnt signalling pathways have been implicated in a wide spectrum of important biological phenomena, ranging from early organismal development to cell behaviours to several diseases, especially cancers. Emergence of the field of Wnt signalling can be largely traced back to the discovery of the first mammalian Wnt gene in 1982. In this essay, we mark the thirtieth anniversary of that discovery by describing some of the critical scientific developments that led to the flowering of this field of research.
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173
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Edwards TL, Burt BO, Black GCM, Perveen R, Kearns LS, Staffieri SE, Toomes C, Buttery RG, Mackey DA. Familial retinal detachment associated with COL2A1 exon 2 and FZD4 mutations. Clin Exp Ophthalmol 2012; 40:476-83. [PMID: 22574936 DOI: 10.1111/j.1442-9071.2012.02804.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND To characterize the clinical and genetic abnormalities within two Australian pedigrees with high incidences of retinal detachment and visual disability. DESIGN Prospective review of two extended Australian pedigrees with high rates of retinal detachment. PARTICIPANTS Twenty-two family members from two extended Australian pedigrees with high rates of retinal detachment were examined. METHODS A full ophthalmic history and examination were performed, and DNA was analysed by linkage analysis and mutation screening. MAIN OUTCOME MEASURES Characterization of a causative hereditary gene mutation in each family. RESULTS All affected family members of one pedigree carried a C192A COL2A1 exon 2 mutation. None of the affected family members had early-onset arthritis, hearing abnormalities, abnormal clefting or facial features characteristic of classical Stickler syndrome. All affected members of the familial exudative vitreoretinopathy pedigree carried a 957delG FZD4 mutation. CONCLUSIONS Patients with retinal detachment and a positive family history should be investigated for heritable conditions associated with retinal detachment such as Stickler syndrome and familial exudative vitreoretinopathy. The absence of non-ocular features of Stickler syndrome should raise the possibility of mutations in exon 2 of COL2A1. Similarly, late-onset familial exudative vitreoretinopathy may appear more like a rhegmatogenous detachment and not be correctly diagnosed. When a causative gene mutation is identified, cascade genetic screening of the family will facilitate genetic counselling and screening of high-risk relatives, allowing targeted management of the pre-detachment changes in affected patients.
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Affiliation(s)
- Thomas L Edwards
- Centre for Eye Research Australia, University of Melbourne, Department of Ophthalmology Vitreo-retinal Unit, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria
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174
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Molday RS, Kellner U, Weber BHF. X-linked juvenile retinoschisis: clinical diagnosis, genetic analysis, and molecular mechanisms. Prog Retin Eye Res 2012; 31:195-212. [PMID: 22245536 PMCID: PMC3334421 DOI: 10.1016/j.preteyeres.2011.12.002] [Citation(s) in RCA: 220] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/16/2011] [Accepted: 12/19/2011] [Indexed: 01/07/2023]
Abstract
X-linked juvenile retinoschisis (XLRS, MIM 312700) is a common early onset macular degeneration in males characterized by mild to severe loss in visual acuity, splitting of retinal layers, and a reduction in the b-wave of the electroretinogram (ERG). The RS1 gene (MIM 300839) associated with the disease encodes retinoschisin, a 224 amino acid protein containing a discoidin domain as the major structural unit, an N-terminal cleavable signal sequence, and regions responsible for subunit oligomerization. Retinoschisin is secreted from retinal cells as a disulphide-linked homo-octameric complex which binds to the surface of photoreceptors and bipolar cells to help maintain the integrity of the retina. Over 190 disease-causing mutations in the RS1 gene are known with most mutations occurring as non-synonymous changes in the discoidin domain. Cell expression studies have shown that disease-associated missense mutations in the discoidin domain cause severe protein misfolding and retention in the endoplasmic reticulum, mutations in the signal sequence result in aberrant protein synthesis, and mutations in regions flanking the discoidin domain cause defective disulphide-linked subunit assembly, all of which produce a non-functional protein. Knockout mice deficient in retinoschisin have been generated and shown to display most of the characteristic features found in XLRS patients. Recombinant adeno-associated virus (rAAV) mediated delivery of the normal RS1 gene to the retina of young knockout mice result in long-term retinoschisin expression and rescue of retinal structure and function providing a 'proof of concept' that gene therapy may be an effective treatment for XLRS.
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Affiliation(s)
- Robert S Molday
- Department of Biochemistry and Molecular Biology, Centre of Macular Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, B.C. V6T 1Z3, Canada.
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175
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Shukla SY, Kaliki S, Shields CL. Asymmetry of familial exudative vitreoretinopathy. J Pediatr Ophthalmol Strabismus 2012; 49 Online:e5-8. [PMID: 22372757 DOI: 10.3928/01913913-20120221-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 01/10/2012] [Indexed: 01/22/2023]
Abstract
A 2-month-old male infant presented with unilateral leukocoria suspected to be retinoblastoma. Fundus examination and fluorescein angiography confirmed the diagnosis of bilateral familial exudative vitreoretinopathy with markedly asymmetric presentation (Stage 3/Type 5 in the right eye and Stage 2/Type 3 in the left eye).
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Affiliation(s)
- Shripaad Y Shukla
- Ocular Oncology Service, Wills Eye Institute, 840 Walnut Street, Suite 1440, Philadelphia, PA 19107, USA
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176
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Norrin: molecular and functional properties of an angiogenic and neuroprotective growth factor. Prog Retin Eye Res 2012; 31:243-57. [PMID: 22387751 DOI: 10.1016/j.preteyeres.2012.02.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 02/08/2012] [Accepted: 02/08/2012] [Indexed: 01/08/2023]
Abstract
Norrin is a secreted signaling molecule with structural and functional characteristics of an autocrine and/or paracrine acting growth factor. In the eye, Norrin is constitutively expressed in Müller cells. Norrin specifically binds to Frizzled-4 receptors and activates the canonical Wnt/β-catenin signaling pathway that is profoundly enhanced when Tspan12 is present at the Norrin/Frizzled-4 receptor complex. In the absence of Norrin or Frizzled-4, intraretinal capillaries are not formed during developmental angiogenesis. As a result there is considerable evidence that Norrin and Frizzled-4 are part of an essential signaling system that controls the formation of the retinal vasculature during eye development. Intriguingly, Norrin promotes vessel regrowth and induces the formation of intraretinal capillaries following oxygen-induced retinopathy in mice, an animal model of retinopathy of prematurity. Moreover, Norrin has pronounced neuroprotective properties on retinal ganglion cells (RGC) with the distinct potential to decrease the damaging effects of excitotoxic NMDA-induced RGC injury. The neuroprotective effects of Norrin similarly involve an activation of Wnt/β-catenin signaling and the subsequent induction of neuroprotective growth factor synthesis in Müller cells, such as that of fibroblast growth factor-2 (FGF2) or ciliary neurotrophic factor (CNTF). Overall, Norrin and the molecules involved in its signaling pathway appear to be promising targets to develop strategies that induce intraretinal vessel formation in patients suffering from ischemic retinopathies, or that increase RGC survival in glaucoma.
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177
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Chen J, Stahl A, Krah NM, Seaward MR, Joyal JS, Juan AM, Hatton CJ, Aderman CM, Dennison RJ, Willett KL, Sapieha P, Smith LEH. Retinal expression of Wnt-pathway mediated genes in low-density lipoprotein receptor-related protein 5 (Lrp5) knockout mice. PLoS One 2012; 7:e30203. [PMID: 22272305 PMCID: PMC3260226 DOI: 10.1371/journal.pone.0030203] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/12/2011] [Indexed: 01/13/2023] Open
Abstract
Mutations in low-density lipoprotein receptor-related protein 5 (Lrp5) impair retinal angiogenesis in patients with familial exudative vitreoretinopathy (FEVR), a rare type of blinding vascular eye disease. The defective retinal vasculature phenotype in human FEVR patients is recapitulated in Lrp5 knockout (Lrp5−/−) mouse with delayed and incomplete development of retinal vessels. In this study we examined gene expression changes in the developing Lrp5−/− mouse retina to gain insight into the molecular mechanisms that underlie the pathology of FEVR in humans. Gene expression levels were assessed with an Illumina microarray on total RNA from Lrp5−/− and WT retinas isolated on postnatal day (P) 8. Regulated genes were confirmed using RT-qPCR analysis. Consistent with a role in vascular development, we identified expression changes in genes involved in cell-cell adhesion, blood vessel morphogenesis and membrane transport in Lrp5−/− retina compared to WT retina. In particular, tight junction protein claudin5 and amino acid transporter slc38a5 are both highly down-regulated in Lrp5−/− retina. Similarly, several Wnt ligands including Wnt7b show decreased expression levels. Plasmalemma vesicle associated protein (plvap), an endothelial permeability marker, in contrast, is up-regulated consistent with increased permeability in Lrp5−/− retinas. Together these data suggest that Lrp5 regulates multiple groups of genes that influence retinal angiogenesis and may contribute to the pathogenesis of FEVR.
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Affiliation(s)
- Jing Chen
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Andreas Stahl
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
- University Eye Hospital Freiburg, Freiburg, Germany
| | - Nathan M. Krah
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Molly R. Seaward
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Jean-Sebastian Joyal
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Aimee M. Juan
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Colman J. Hatton
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Christopher M. Aderman
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Roberta J. Dennison
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Keirnan L. Willett
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Przemyslaw Sapieha
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, Canada
| | - Lois E. H. Smith
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts, United States of America
- * E-mail:
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178
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Katanaev VL, Kryuchkov MV. The eye of Drosophila as a model system for studying intracellular signaling in ontogenesis and pathogenesis. BIOCHEMISTRY (MOSCOW) 2012; 76:1556-81. [DOI: 10.1134/s0006297911130116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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179
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Descamps B, Sewduth R, Ferreira Tojais N, Jaspard B, Reynaud A, Sohet F, Lacolley P, Allières C, Lamazière JMD, Moreau C, Dufourcq P, Couffinhal T, Duplàa C. Frizzled 4 Regulates Arterial Network Organization Through Noncanonical Wnt/Planar Cell Polarity Signaling. Circ Res 2012; 110:47-58. [DOI: 10.1161/circresaha.111.250936] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Rationale:
A growing body of evidence supports the hypothesis that the Wnt/planar cell polarity (PCP) pathway regulates endothelial cell proliferation and angiogenesis, but the components that mediate this regulation remain elusive.
Objective:
We investigated the involvement of one of the receptors, Frizzled4 (Fzd4), in this process because its role has been implicated in retinal vascular development.
Methods and Results:
We found that loss of
fzd4
function in mice results in a striking reduction and impairment of the distal small artery network in the heart and kidney. We report that loss of
fzd4
decreases vascular cell proliferation and migration and decreases the ability of the endothelial cells to form tubes. We show that
fzd4
deletion induces defects in the expression level of stable acetylated tubulin and in Golgi organization during migration. Deletion of
fzd4
favors Wnt noncanonical AP1-dependent signaling, indicating that Fzd4 plays a pivotal role favoring PCP signaling. Our data further demonstrate that Fzd4 is predominantly localized on the top of the plasma membrane, where it preferentially induces Dvl3 relocalization to promote its activation and α-tubulin recruitment during migration. In a pathological mouse angiogenic model, deletion of
fzd4
impairs the angiogenic response and leads to the formation of a disorganized arterial network.
Conclusions:
These results suggest that Fzd4 is a major receptor involved in arterial formation and organization through a Wnt/PCP pathway.
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Affiliation(s)
- Betty Descamps
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Raj Sewduth
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Nancy Ferreira Tojais
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Béatrice Jaspard
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Annabel Reynaud
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Fabien Sohet
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Patrick Lacolley
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Cécile Allières
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Jean-Marie Daniel Lamazière
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Catherine Moreau
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Pascale Dufourcq
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Thierry Couffinhal
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
| | - Cécile Duplàa
- From the Inserm (B.D., R.S., N.F.T., B.J., A.R., C.A., J.-M.D.L., C.M., P.D., T.C., C.D.), U1034, Pessac, France and University de Bordeaux, Bordeaux, France; Unité Inserm U872 (F.S.), Centre de Recherche des Cordeliers, Paris, France; Université Henri Poincaré (P.L., P.D.), Inserm U961, Nancy, France; Laboratoire de biochimie (T.C.), UFR Sciences Pharmaceutiques, University de Bordeaux, Bordeaux, France; Department of Cardiology (C.D.), Pôle Cardiothoracique, Hôpital Haut Lévêque, Pessac, France
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Tarapore RS, Siddiqui IA, Mukhtar H. Modulation of Wnt/β-catenin signaling pathway by bioactive food components. Carcinogenesis 2011; 33:483-91. [PMID: 22198211 DOI: 10.1093/carcin/bgr305] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Wnt/β-catenin signaling pathway, one of the most conserved intercellular signaling cascade, is a known regulator of cellular functions related to tumor initiation and progression, cell proliferation, differentiation, survival and adhesion. Because aberrant Wnt/β-catenin signaling has been observed in a variety of human cancers including a majority of colorectal cancers, about half of prostate cancers and a third of melanomas, inhibitors of its complex signaling pathways are being investigated for therapy as well as chemoprevention of these cancers. During the last decade, several naturally occurring dietary agents have been shown to target intermediates in the Wnt/β-catenin signaling pathway. In this review, we highlight the current understanding of the Wnt/β-catenin signaling pathway and present an analysis of the key findings from laboratory studies on the effects of a panel of dietary agents against a variety of cancers. Promise of these agents for treating and preventing human cancer is then discussed.
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Affiliation(s)
- Rohinton S Tarapore
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Medical Sciences Center, #B-25, 1300 University Avenue, Madison, WI 53706, USA
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Jakobiec FA, Zakka FR, D'Amato R, Deangelis MM, Walton DS, Rao RC. Unilateral sporadic retinal dysplasia: results of histopathologic, immunohistochemical, chromosomal, genetic, and VEGF-A analyses. J AAPOS 2011; 15:579-86. [PMID: 22153404 PMCID: PMC4242509 DOI: 10.1016/j.jaapos.2011.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 07/28/2011] [Accepted: 08/19/2011] [Indexed: 11/16/2022]
Abstract
PURPOSE To describe new findings in a case of unilateral retinal dysplasia. METHODS Histopathologic evaluation of an enucleated globe and analysis with immunohistochemical probes, karyotyping, and genetic analysis for the Norrie gene, and aqueous assay for vascular endothelial growth factor A (VEGF-A). RESULTS Histopathological examination of the globe revealed retinal dysplasia with pseudorosette formation, abnormal or absent retinal nuclear lamination, a paucity of disorganized retinal microvasculature, retinal infoldings, advanced gliosis, persistent hyperplastic vitreous, exuberant neovascularization of the vitreous, and iris neovascularization (identical to the findings observed in bilateral Norrie disease). Immunohistochemistry disclosed GFAP-positive and GLUT-1-positive gliosis and retinal and persistent hyperplastic vitreous microvessels that were CD34-positive and GLUT-1-negative. Ki-67-positive retinal cells were polarized toward the subretinal space and absent in the retinal invaginations and pseudorosettes. A normal karyotype was found, and DNA sequencing revealed no known mutation in the region of the Norrie gene (NDP) in sputum or retinal DNA. Aqueous obtained immediately after enucleation contained an exceptionally high concentration of VEGF-A (4.5 ng/mL). CONCLUSIONS Despite the failure to find an abnormal NDP allele, other unexplored NDP regions, an undetected defect restricted to retinal tissues, or an autosomal mutation coupled with disrupted signaling pathways may be responsible for the condition. High aqueous VEGF-A suggests that this cytokine may play a role in pathogenesis in conjunction with other pathways.
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Affiliation(s)
- Frederick A Jakobiec
- David G. Cogan Laboratory of Ophthalmic Pathology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02114, USA.
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183
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De Marco P, Merello E, Rossi A, Piatelli G, Cama A, Kibar Z, Capra V. FZD6 is a novel gene for human neural tube defects. Hum Mutat 2011; 33:384-90. [PMID: 22045688 PMCID: PMC3482927 DOI: 10.1002/humu.21643] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 10/07/2011] [Indexed: 01/14/2023]
Abstract
Neural tube defects (NTDs) are severe malformations of the central nervous system, affecting 1 of 1,000 live births. Mouse models were instrumental in defining the signaling pathways defective in NTDs, including the planar cell polarity (PCP), also called noncanonical Frizzled/Disheveled pathway. Based on the highly penetrant occurrence of NTDs in double Fzd3/Fzd6(-/-) mutant mice, we investigated the role of the human orthologues, FZD3 and FZD6, by resequencing a cohort of 473 NTDs patients and 639 ethnically matched controls. While we could not demonstrate a significant contribution of FZD3 gene, we identified five rare FZD6 variants that were absent in all controls and predicted to have a functional effect by computational analysis: one de novo frameshift mutation (c.1843_1844insA), three missense changes (p.Arg405Gln, p.Arg511Cys p.Arg511His), and one substitution (c.*20C>T) affecting the 3'-untranslated region (UTR) of the gene. The overall rate of predicted deleterious variants of FZD6 was 5.1-fold higher in cases compared to controls, resulting in a significantly increased NTDs mutation burden. This study demonstrates that rare nonsynonymous variants in FZD6 may contribute to NTDs in humans and enlarges the spectrum of mutations that link PCP pathway to NTDs.
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184
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Chen J, Stahl A, Krah NM, Seaward MR, Dennison RJ, Sapieha P, Hua J, Hatton CJ, Juan AM, Aderman CM, Willett KL, Guerin KI, Mammoto A, Campbell M, Smith LEH. Wnt signaling mediates pathological vascular growth in proliferative retinopathy. Circulation 2011; 124:1871-81. [PMID: 21969016 PMCID: PMC3326389 DOI: 10.1161/circulationaha.111.040337] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Ischemic proliferative retinopathy, characterized by pathological retinal neovascularization, is a major cause of blindness in working-age adults and children. Defining the molecular pathways distinguishing pathological neovascularization from normal vessels is critical to controlling these blinding diseases with targeted therapy. Because mutations in Wnt signaling cause defective retinal vasculature in humans with some characteristics of the pathological vessels in retinopathy, we investigated the potential role of Wnt signaling in pathological retinal vascular growth in proliferative retinopathy. METHODS AND RESULTS In this study, we show that Wnt receptors (Frizzled4 and low-density lipoprotein receptor-related protein5 [Lrp5]) and activity are significantly increased in pathological neovascularization in a mouse model of oxygen-induced proliferative retinopathy. Loss of Wnt coreceptor Lrp5 and downstream signaling molecule dishevelled2 significantly decreases the formation of pathological retinal neovascularization in retinopathy. Loss of Lrp5 also affects retinal angiogenesis during development and formation of the blood-retinal barrier, which is linked to significant downregulation of tight junction protein claudin5 in Lrp5(-/-) vessels. Blocking claudin5 significantly suppresses Wnt pathway-driven endothelial cell sprouting in vitro and developmental and pathological vascular growth in retinopathy in vivo. CONCLUSIONS These results demonstrate an important role of Wnt signaling in pathological vascular development in retinopathy and show a novel function of Cln5 in promoting angiogenesis.
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MESH Headings
- Animals
- Cell Proliferation
- Cells, Cultured
- Disease Models, Animal
- Endothelium, Vascular/growth & development
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Frizzled Receptors/biosynthesis
- Frizzled Receptors/physiology
- Humans
- Low Density Lipoprotein Receptor-Related Protein-5/biosynthesis
- Low Density Lipoprotein Receptor-Related Protein-5/physiology
- Lysosomal Membrane Proteins
- Membrane Glycoproteins/biosynthesis
- Mice
- Mice, Knockout
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/pathology
- Receptors, Wnt/biosynthesis
- Receptors, Wnt/physiology
- Retina/growth & development
- Retina/pathology
- Retina/physiology
- Wnt Signaling Pathway/physiology
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Affiliation(s)
- Jing Chen
- Department of Ophthalmology, Harvard Medical School/Children's Hospital Boston, Boston MA 02115, USA
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185
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Nalesso G, Sherwood J, Bertrand J, Pap T, Ramachandran M, De Bari C, Pitzalis C, Dell'accio F. WNT-3A modulates articular chondrocyte phenotype by activating both canonical and noncanonical pathways. ACTA ACUST UNITED AC 2011; 193:551-64. [PMID: 21536751 PMCID: PMC3087013 DOI: 10.1083/jcb.201011051] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A single Wnt can simultaneously activate different pathways with distinct and independent outcomes and reciprocal regulation in human articular chondrocytes. Activation and disruption of Wnt/β-catenin signaling both result in cartilage breakdown via unknown mechanisms. Here we show that both WNT-3A and the Wnt inhibitor DKK1 induced de-differentiation of human articular chondrocytes through simultaneous activation of β-catenin–dependent and independent responses. WNT-3A activates both the β-catenin–dependent canonical pathway and the Ca2+/CaMKII noncanonical pathways, with distinct transcriptional targets. WNT-3A promotes cell proliferation and loss of expression of the chondrocyte markers COL2A1, Aggrecan, and SOX9; however, proliferation and AXIN2 up-regulation are downstream of the canonical pathway and are rescued by DKK1, whereas the loss of differentiation markers is CaMKII dependent. Finally, we showed that in chondrocytes, the Ca2+/CaMKII-dependent and β-catenin–dependent pathways are reciprocally inhibitory, thereby explaining why DKK1 can induce loss of differentiation through de-repression of the CaMKII pathway. We propose a novel model in which a single WNT can simultaneously activate different pathways with distinct and independent outcomes and with reciprocal regulation. This offers an opportunity for selective pharmacological targeting.
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Affiliation(s)
- Giovanna Nalesso
- Centre for Experimental Medicine and Rheumatology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London EC1M6BQ, England, UK
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186
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Waryah AM, Ahmed ZM, Bhinder MA, Binder MA, Choo DI, Sisk RA, Shahzad M, Khan SN, Friedman TB, Riazuddin S, Riazuddin S. Molecular and clinical studies of X-linked deafness among Pakistani families. J Hum Genet 2011; 56:534-40. [PMID: 21633365 PMCID: PMC3143270 DOI: 10.1038/jhg.2011.55] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There are 68 sex-linked syndromes that include hearing loss as one feature and five sex-linked nonsyndromic deafness loci listed in the OMIM database. The possibility of additional such sex-linked loci was explored by ascertaining three unrelated Pakistani families (PKDF536, PKDF1132, PKDF740) segregating X-linked recessive deafness. Sequence analysis of POU3F4 (DFN3) in affected members of families PKDF536 and PKDF1132 revealed two novel nonsense mutations, p.Q136X and p.W114X, respectively. Family PKDF740 is segregating congenital blindness, mild to profound progressive hearing loss that is characteristic of Norrie disease (MIM#310600). Sequence analysis of NDP among affected members of this family revealed a novel single nucleotide deletion c.49delG causing a frameshift and premature truncation (p.V17fsX1) of the encoded protein. These mutations were not found in 150 normal DNA samples. Identification of pathogenic alleles causing X-linked recessive deafness will improve molecular diagnosis, genetic counseling, and molecular epidemiology of hearing loss among Pakistanis.
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Affiliation(s)
- Ali M Waryah
- National Center of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
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187
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Kondo H, Kusaka S, Yoshinaga A, Uchio E, Tawara A, Hayashi K, Tahira T. Mutations in the TSPAN12 gene in Japanese patients with familial exudative vitreoretinopathy. Am J Ophthalmol 2011; 151:1095-1100.e1. [PMID: 21334594 DOI: 10.1016/j.ajo.2010.11.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 11/18/2010] [Accepted: 11/19/2010] [Indexed: 11/19/2022]
Abstract
PURPOSE To search for mutations in the TSPAN12 gene in 90 Japanese probands with familial exudative vitreoretinopathy (FEVR) and their family members and to determine the types and frequencies of the mutations. DESIGN Laboratory investigation and clinical case analyses. METHODS Direct sequencing after polymerase chain reaction of the coding exons of TSPAN12 was performed for 90 probands with FEVR and some of their family members. The clinical signs and symptoms that were characteristic of individuals with TSPAN12 mutations were determined. RESULTS Three families were found to carry 2 mutations in TSPAN12. One of these mutations was a new missense change, L245P, and the other was an already reported nonsense mutation, L140X, in 2 families. Mutations in TSPAN12 accounted for 3% of Japanese FEVR patients and 8% of the FEVR families who did not have mutations in any of the known FEVR genes, FZD4, LRP5, and NDP. The clinical signs and symptoms varied among the patients, but the retinal findings with TSPAN12 mutations were not different from those with mutations in the known FEVR-causing genes. CONCLUSIONS Mutant TSPAN12 is responsible for approximately 3% of FEVR patients in Japan. The results provide further evidence that mutations in TSPAN12 are FEVR causing and that the gene products most likely play a role in the development of retinal vessels.
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Affiliation(s)
- Hiroyuki Kondo
- Department of Ophthalmology, University of Occupational and Environmental Health Japan, Kitakyushu, Japan.
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188
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Toiviainen-Salo S, Linnankivi T, Saarinen A, Mäyränpää MK, Karikoski R, Mäkitie O. Cerebroretinal microangiopathy with calcifications and cysts: characterization of the skeletal phenotype. Am J Med Genet A 2011; 155A:1322-8. [PMID: 21523908 DOI: 10.1002/ajmg.a.33994] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 02/18/2011] [Indexed: 11/05/2022]
Abstract
Cerebral cysts and calcifications with leukoencephalopathy and retinal vascular abnormalities are diagnostic hallmarks of cerebroretinal microangiopathy with calcifications and cysts (CRMCC). Previous studies have suggested that skeletal involvement is also common, but its characteristics remain unknown. This study aimed to assess the skeletal phenotype in CRMCC. All Finnish patients with features consistent with CRMCC and for whom radiographs were available were included. Clinical information pertinent to the skeletal phenotype was collected from hospital records, and all plain radiographs were reviewed for skeletal features. Bone mineral density (BMD) was measured by DXA. In one patient, bone biopsies were obtained for bone histology and histomorphometric analyses. The LRP5 gene was analyzed for mutations by direct sequencing. Our results show that the skeletal phenotype in CRMCC includes (1) compromised longitudinal growth pre- and postnatally, (2) generalized osteopenia or early onset low turnover osteoporosis with fragility fractures, and (3) metaphyseal abnormalities that may lead to limb deformities such as short femoral neck or genua valga. DXA measurements in three patients showed low BMD, and bone biopsies in the fourth patient with pathological fractures and impaired fracture healing showed low-turnover osteoporosis, with reduced osteoclast and osteoblast activity. Direct sequencing of all LRP5 coding exons and exon-intron boundaries in six patients with CRMCC revealed no putative mutations. We conclude that the CRMCC-associated bone disease is characterized by low BMD and pathological fractures with delayed healing, metaphyseal changes, and short stature pre- and postnatally. LRP5 is not a disease-causing gene in CRMCC.
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189
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Murata-Kamiya N. Pathophysiological functions of the CagA oncoprotein during infection by Helicobacter pylori. Microbes Infect 2011; 13:799-807. [PMID: 21477660 DOI: 10.1016/j.micinf.2011.03.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Revised: 03/26/2011] [Accepted: 03/28/2011] [Indexed: 02/06/2023]
Abstract
Infection with Helicobacter pylori cagA-positive strains plays an essential role in the development of gastric carcinoma. This review summarizes the pathophysiological functions of the cagA gene product, CagA, particularly focusing on the molecular mechanisms underlying CagA translocation into the host cells as well as CagA-mediated deregulation of host cell signaling.
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Affiliation(s)
- Naoko Murata-Kamiya
- Division of Microbiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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190
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Familial exudative vitreoretinopathy with an anterior segment vasoproliferative mass. Graefes Arch Clin Exp Ophthalmol 2011; 250:467-8. [PMID: 21455775 DOI: 10.1007/s00417-011-1664-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/06/2011] [Accepted: 03/07/2011] [Indexed: 10/18/2022] Open
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191
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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: 164] [Impact Index Per Article: 12.6] [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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192
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Pancratov R, DasGupta R. Postgenomic technologies targeting the Wnt signaling network. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 3:649-65. [PMID: 21381216 DOI: 10.1002/wsbm.140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The recent development of high-throughput sequencing technologies and the availability of whole genome sequences of a variety of living organisms, including that of humans, have led to an enormous push in the quest for a comprehensive inquiry for the function of each and every gene discovered in different model organisms. A major conclusion from the sequencing projects was that while forward genetics had been extremely successful in identifying key genes/components of many biological processes, such as signal transduction cascades, the function(s) of the majority of genes in the genome remains a mystery. In this article, we discuss the use of a variety of high-throughput postgenomic tools, including functional genomics, proteomics, and chemical genetics that are being implemented in an exhaustive molecular dissection of a key evolutionarily conserved signal transduction pathway, namely the Wnt/wingless (wg) pathway and its associated signaling network.
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Affiliation(s)
- Raluca Pancratov
- Department of Pharmacology, New York University School of Medicine and NYU Cancer Institute, New York, NY, USA
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193
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Zhang K, Harada Y, Wei X, Shukla D, Rajendran A, Tawansy K, Bedell M, Lim S, Shaw PX, He X, Yang Z. An essential role of the cysteine-rich domain of FZD4 in Norrin/Wnt signaling and familial exudative vitreoretinopathy. J Biol Chem 2010; 286:10210-5. [PMID: 21177847 DOI: 10.1074/jbc.m110.194399] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The Wnt pathway plays important yet diverse roles in health and disease. Mutations in the Wnt receptor FZD4 gene have been confirmed to cause familial exudative vitreoretinopathy (FEVR). FEVR is characterized by incomplete vascularization of the peripheral retina, which can lead to vitreous bleeding, tractional retinal detachment, and blindness. We screened for mutations in the FZD4 gene in five families with FEVR and identified five mutations (C45Y, Y58C, W226X, C204R, and W496X), including three novel mutations (C45Y, Y58C, and W226X). In the retina, Norrin serves as a ligand and binds to FZD4 to activate the Wnt signaling pathway in normal angiogenesis and vascularization. The cysteine-rich domain (CRD) of FZD4 has been shown to play a critical role in Norrin-FZD4 binding. We investigated the effect of mutations in the FZD4 CRD in Norrin binding and signaling in vitro and in vivo. Wild-type and mutant FZD4 proteins were assayed for Norrin binding and Norrin-dependent activation of the canonical Wnt pathway by cell-surface and overlay binding assays and luciferase reporter assays. In HEK293 transfection studies, C45Y, Y58C, and C204R mutants did not bind to Norrin and failed to transduce FZD4-mediated Wnt/β-catenin signaling. In vivo studies using Xenopus embryos showed that these FZD4 mutations disrupt Norrin/β-catenin signaling as evidenced by decreased Siamois and Xnr3 expression. This study identified a new class of FZD4 gene mutations in human disease and demonstrates a critical role of the CRD in Norrin binding and activation of the β-catenin pathway.
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Affiliation(s)
- Kang Zhang
- Molecular Medicine Research Center and Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China 610041.
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194
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Zhang B, Ma JX. Wnt pathway antagonists and angiogenesis. Protein Cell 2010; 1:898-906. [PMID: 21204016 DOI: 10.1007/s13238-010-0112-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Accepted: 09/27/2010] [Indexed: 11/26/2022] Open
Abstract
Dysregulation of the Wnt pathway has been extensively studied in multiple diseases, including some angiogenic disorders. Wnt signaling activation is a major stimulator in pathological angiogenesis and thus, Wnt antagonists are believed to have therapeutic potential for neovascular disorders. Actually, some Wnt antagonists have been identified directly from the anti-angiogenic factor family. This review summarizes the recent progress toward understanding of the roles of Wnt pathway antagonists in angiogenic regulation and their mechanism of action, and exploring their therapeutic potential.
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Affiliation(s)
- Bin Zhang
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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195
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Lad EM, Cheshier SH, Kalani MYS. Wnt-signaling in retinal development and disease. Stem Cells Dev 2010; 18:7-16. [PMID: 18690791 DOI: 10.1089/scd.2008.0169] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Wnt-signaling pathway is a known regulator of stem cell maintenance, cellular proliferation and differentiation, and cancer development in various tissues. Wnt proteins play a central role during various stages of retinal development; retinal field establishment, retinal and hyaloid vasculogenesis, cornea and lens development, eye field formation, and maintenance of retinal stem cell and neuronal specification in many species are Wnt-regulated processes. Uncontrolled Wnt signaling may cause retinal diseases such as familial exudative vitroretinopathy, retinitis pigmentosa, and Norrie's disease, further underscoring the importance of the Wnt-signaling pathway in the retina. This review summarizes major developments and discoveries regarding the role of the Wnt-signaling pathway as it pertains to retinal development and disease.
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Affiliation(s)
- Eleonora M Lad
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, California 94305, USA
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196
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Ye X, Wang Y, Nathans J. The Norrin/Frizzled4 signaling pathway in retinal vascular development and disease. Trends Mol Med 2010; 16:417-25. [PMID: 20688566 DOI: 10.1016/j.molmed.2010.07.003] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 07/09/2010] [Accepted: 07/09/2010] [Indexed: 01/22/2023]
Abstract
Disorders of retinal vascular growth and function are responsible for vision loss in a variety of diseases, including diabetic retinopathy, age-related macular degeneration, retinopathy of prematurity and retinal artery or vein occlusion. Over the past decade, a new signaling pathway that controls retinal vascular development has emerged from the study of inherited disorders - in both humans and mice - that are characterized by retinal hypovascularization. This pathway utilizes a glial-derived extracellular ligand, Norrin, that acts on a transmembrane receptor, Frizzled4, a coreceptor, Lrp5, and an auxiliary membrane protein, Tspan12, on the surface of developing endothelial cells. The resulting signal controls a transcriptional program that regulates endothelial growth and maturation. It will be of great interest to determine whether modulating this pathway could represent a therapeutic approach to human retinal vascular disease.
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Affiliation(s)
- Xin Ye
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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197
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Abstract
Growth factor signaling is required for cellular differentiation, tissue morphogenesis, and tissue homeostasis. Misregulation of intracellular signal transduction can lead to developmental defects during embryogenesis or particular diseases in the adult. One family of growth factors important for these aspects is given by the Wnt proteins. In particular, Wnts have important functions in stem cell biology, cardiac development and differentiation, angiogenesis, cardiac hypertrophy, cardiac failure, and aging. Knowledge of growth factor signaling during differentiation will allow for improvement of targeted differentiation of embryonic or adult stem cells toward functional cardiomyocytes or for understanding the basis of diseases. Our major aim here is to provide a state of the art review summarizing our present knowledge of the intracellular Wnt-mediated signaling network. In particular, we provide evidence that the subdivision into canonical and noncanonical Wnt signaling pathways solely based on the identity of Wnt ligands or Frizzled receptors is not appropriate anymore. We thereby deliver a solid base for further upcoming articles of a review series focusing on the role of Wnt proteins on different aspects of cardiovascular development and dysfunction.
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Affiliation(s)
- Tata Purushothama Rao
- Institute for Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
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198
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LRP5 is required for vascular development in deeper layers of the retina. PLoS One 2010; 5:e11676. [PMID: 20652025 PMCID: PMC2907392 DOI: 10.1371/journal.pone.0011676] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 06/28/2010] [Indexed: 11/19/2022] Open
Abstract
Background The low-density lipoprotein receptor-related protein 5 (LRP5) plays an important role in the development of retinal vasculature. LRP5 loss-of-function mutations cause incomplete development of retinal vessel network in humans as well as in mice. To understand the underlying mechanism for how LRP5 mutations lead to retinal vascular abnormalities, we have determined the retinal cell types that express LRP5 and investigated specific molecular and cellular functions that may be regulated by LRP5 signaling in the retina. Methods and Findings We characterized the development of retinal vasculature in LRP5 mutant mice using specific retinal cell makers and a GFP transgene expressed in retinal endothelial cells. Our data revealed that retinal vascular endothelial cells predominantly formed cell clusters in the inner-plexiform layer of LRP5 mutant retina rather than sprouting out or migrating into deeper layers to form normal vascular network in the retina. The IRES-β-galactosidase (LacZ) report gene under the control of the endogenous LRP5 promoter was highly expressed in Müller cells and was also weakly detected in endothelial cells of the retinal surface vasculature. Moreover, the LRP5 mutant mice had a reduction of a Müller cell-specific glutamine transporter, Slc38a5, and showed a decrease in b-wave amplitude of electroretinogram. Conclusions LRP5 is not only essential for vascular endothelial cells to sprout, migrate and/or anastomose in the deeper plexus during retinal vasculature development but is also important for the functions of Müller cells and retinal interneurons. Müller cells may utilize LRP5-mediated signaling pathway to regulate vascular development in deeper layers and to maintain the function of retinal interneurons.
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199
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Glaw JT, Skalak TC, Peirce SM. Inhibition of canonical Wnt signaling increases microvascular hemorrhaging and venular remodeling in adult rats. Microcirculation 2010; 17:348-57. [PMID: 20618692 PMCID: PMC2904644 DOI: 10.1111/j.1549-8719.2010.00036.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The canonical Wnt signaling pathway, heavily studied in development and cancer, has recently been implicated in microvascular growth with the use of developmental and in vitro models. To date, however, no study exists showing the effects of perturbing the canonical Wnt pathway in a complete microvascular network undergoing physiological remodeling in vivo. Our objective was to investigate the effects of canonical Wnt inhibition on the microvascular remodeling of adult rats. METHODS Canonical Wnt inhibitor DKK-1, Wnt inhibitor sFRP-1, BSA or saline was superfused onto the exteriorized mesenteric windows of 300 g adult female Sprague-Dawley rats for 20 minutes. Three days following surgery, mesenteric windows were imaged intravitally and harvested for immunofluorescence staining with smooth muscle alpha-actin and BRDU. RESULTS We observed prominent differences in the response of the mesenteric microvasculature amongst the various treatment groups. Significant increases in hemorrhage area, vascular density, and draining vessel diameter were observed in windows treated with Wnt inhibitors as compared to control-treated windows. Additionally, confocal imaging analysis showed significant increases in proliferating cells as well as evidence of proliferating smooth muscle cells along venules. CONCLUSIONS Together, our results suggest that canonical Wnt inhibition plays an important role in microvascular remodeling, specifically venular remodeling.
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Affiliation(s)
- Jason T Glaw
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA
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Stahl A, Connor KM, Sapieha P, Chen J, Dennison RJ, Krah NM, Seaward MR, Willett KL, Aderman CM, Guerin KI, Hua J, Löfqvist C, Hellström A, Smith LEH. The mouse retina as an angiogenesis model. Invest Ophthalmol Vis Sci 2010; 51:2813-26. [PMID: 20484600 DOI: 10.1167/iovs.10-5176] [Citation(s) in RCA: 474] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The mouse retina has been used extensively over the past decades to study both physiologic and pathologic angiogenesis. Over time, various mouse retina models have evolved into well-characterized and robust tools for in vivo angiogenesis research. This article is a review of the angiogenic development of the mouse retina and a discussion of some of the most widely used vascular disease models. From the multitude of studies performed in the mouse retina, a selection of representative works is discussed in more detail regarding their role in advancing the understanding of both the ocular and general mechanisms of angiogenesis.
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Affiliation(s)
- Andreas Stahl
- Department of Ophthalmology, Harvard Medical School, Children's Hospital Boston, Boston, Massachusetts 02115, USA
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