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Cerecedo D, Martínez-Vieyra I, Hernández-Rojo I, Hernández-Cruz A, Rincón-Heredia R, Millán-Aldaco D, Mendoza-Garrido ME. Reactive oxygen species downregulate dystroglycans in the megakaryocytes of rats with arterial hypertension. Exp Cell Res 2023; 433:113847. [PMID: 37931771 DOI: 10.1016/j.yexcr.2023.113847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/28/2023] [Accepted: 10/29/2023] [Indexed: 11/08/2023]
Abstract
Hypertension is a multifactorial disease characterized by vascular and renal dysfunction, cardiovascular remodeling, inflammation, and fibrosis, all of which are associated with oxidative stress. We previously demonstrated cellular reactive oxygen species (ROS) imbalances may impact the structural and biochemical functions of blood cells and reported downregulation of β-dystroglycan (β-Dg) and overexpression of the epithelial sodium channel (ENaC) contribute to the pathophysiology of hypertension. In this study, we aimed to determine the expression of dystroglycans (Dg) and ENaC in platelet progenitors (megakaryocytes) and their surrounding niches. Thin sections of bone marrow from 5- and 28-week-old spontaneous hypertensive rats (SHR) were compared to age-matched normotensive rats (WKY). Cytometry and immunohistochemical assays demonstrated an oxidative environment in SHR bone marrow, characterized by high levels of myeloperoxidase and 3-nitrotyrosine and downregulation of peroxiredoxin II. In addition, transmission electron micrography and confocal microscopy revealed morphological changes in platelets and Mgks from SHR rats, including swollen mitochondria. Quantitative qRT-PCR assays confirmed downregulation of Dg mRNA and immunohistochemistry and western-blotting validated low expression of β-Dg, mainly in the phosphorylated form, in Mgks from 28-week-old SHR rats. Moreover, we observed a progressive increase in β-1 integrin expression in Mgks and extracellular matrix proteins in Mgk niches in SHR rats compared to WKY controls. These results indicate accumulation of ROS promotes oxidative stress within the bone marrow environment and detrimentally affects cellular homeostasis in hypertensive individuals.
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Affiliation(s)
- Doris Cerecedo
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Mexico City, Mexico.
| | - Ivette Martínez-Vieyra
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Isaac Hernández-Rojo
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Arturo Hernández-Cruz
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Ruth Rincón-Heredia
- Microscopy Core Unit, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Diana Millán-Aldaco
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Maria Eugenia Mendoza-Garrido
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
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2
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Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors. Int J Mol Sci 2022; 23:ijms232314809. [PMID: 36499139 PMCID: PMC9738688 DOI: 10.3390/ijms232314809] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 12/03/2022] Open
Abstract
Mutations in the extracellular matrix protein eyes shut homolog (EYS) are a common cause of retinitis pigmentosa, a blinding disease characterized by photoreceptor degeneration. EYS binds to matriglycan, a carbohydrate modification on O-mannosyl glycan substitutions of the cell-surface glycoprotein α-dystroglycan. Patients with mutations in enzymes required for the biosynthesis of matriglycan exhibit syndromic retinal atrophy, along with brain malformations and congenital muscular dystrophy. Protein O-mannosyltransferase 2 (POMT2) is an enzyme required for the synthesis of O-mannosyl glycans. To evaluate the roles of O-mannosyl glycans in photoreceptor health, we generated protein O-mannosyltransferase 2 (pomt2) mutant zebrafish by CRISPR. pomt2 mutation resulted in a loss of matriglycan and abolished binding of EYS protein to α-dystroglycan. Mutant zebrafish presented with hydrocephalus and hypoplasia of the cerebellum, as well as muscular dystrophy. EYS protein was enriched near photoreceptor connecting cilia in the wild-type, but its presence and proper localization was significantly reduced in mutant animals. The mutant retina exhibited mis-localization of opsins and increased apoptosis in both rod and cone photoreceptors. Immunofluorescence intensity of G protein subunit alpha transducin 2 (GNAT2) antibody (a general cone marker) and 1D4 antibody (a long double cone marker) in mutant retinas did not differ from wild-type retinas at 1-month post fertilization, but was reduced at 6 months post fertilization, indicating significant cone degeneration. These data suggest that POMT2-mediated O-mannosyl glycosylation is required for EYS protein localization to the connecting cilium region and photoreceptor survival.
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3
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Wilson SE. Defective perlecan-associated basement membrane regeneration and altered modulation of transforming growth factor beta in corneal fibrosis. Cell Mol Life Sci 2022; 79:144. [PMID: 35188596 PMCID: PMC8972081 DOI: 10.1007/s00018-022-04184-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/14/2022] [Accepted: 02/01/2022] [Indexed: 02/06/2023]
Abstract
In the cornea, the epithelial basement membrane (EBM) and corneal endothelial Descemet's basement membrane (DBM) critically regulate the localization, availability and, therefore, the functions of transforming growth factor (TGF)β1, TGFβ2, and platelet-derived growth factors (PDGF) that modulate myofibroblast development. Defective regeneration of the EBM, and notably diminished perlecan incorporation, occurs via several mechanisms and results in excessive and prolonged penetration of pro-fibrotic growth factors into the stroma. These growth factors drive mature myofibroblast development from both corneal fibroblasts and bone marrow-derived fibrocytes, and then the persistence of these myofibroblasts and the disordered collagens and other matrix materials they produce to generate stromal scarring fibrosis. Corneal stromal fibrosis often resolves completely if the inciting factor is removed and the BM regenerates. Similar defects in BM regeneration are likely associated with the development of fibrosis in other organs where perlecan has a critical role in the modulation of signaling by TGFβ1 and TGFβ2. Other BM components, such as collagen type IV and collagen type XIII, are also critical regulators of TGF beta (and other growth factors) in the cornea and other organs. After injury, BM components are dynamically secreted and assembled through the cooperation of neighboring cells-for example, the epithelial cells and keratocytes for the corneal EBM and corneal endothelial cells and keratocytes for the corneal DBM. One of the most critical functions of these reassembled BMs in all organs is to modulate the pro-fibrotic effects of TGFβs, PDGFs and other growth factors between tissues that comprise the organ.
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Affiliation(s)
- Steven E Wilson
- Cole Eye Institute, I-32, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, USA.
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4
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Sandonà M, Saccone V. Post-translational Modification in Muscular Dystrophies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1382:71-84. [DOI: 10.1007/978-3-031-05460-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Packer D, Martin PT. Micro-laminin gene therapy can function as an inhibitor of muscle disease in the dy W mouse model of MDC1A. Mol Ther Methods Clin Dev 2021; 21:274-287. [PMID: 33869655 PMCID: PMC8026908 DOI: 10.1016/j.omtm.2021.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 02/03/2021] [Indexed: 02/04/2023]
Abstract
Gene replacement for laminin-α2-deficient congenital muscular dystrophy 1A (MDC1A) is currently not possible using a single adeno-associated virus (AAV) vector due to the large size of the LAMA2 gene. LAMA2 encodes laminin-α2, a subunit of the trimeric laminin-211 extracellular matrix (ECM) protein that is the predominant laminin expressed in skeletal muscle. LAMA2 expression stabilizes skeletal muscle, in part by binding membrane receptors via its five globular (G) domains. We created a small, AAV-deliverable, micro-laminin gene therapy that expresses these G1-5 domains, LAMA2(G1-5), to test their therapeutic efficacy in the dyW mouse model for MDC1A. We also fused the heparin-binding (HB) domain from HB epidermal growth factor-like growth factor (HB-EGF) to LAMA2(G1-5) to test whether this would increase muscle ECM expression. dyW mice treated intravenously with rAAV9.CMV.HB-LAMA2(G1-5) showed increased muscle ECM expression of transgenic protein relative to mice treated with rAAV9.CMV.LAMA2(G1-5) and showed improved weight-normalized forelimb grip strength relative to untreated dyW mice. Additionally, dyW muscle fibers expressing either micro-laminin protein showed some measures of reduced pathology, although levels of muscle cell apoptosis and inflammation were not decreased. Although systemic expression of rAAV9.CMV.HB-LAMA2(G1-5) did not inhibit all disease phenotypes, these studies demonstrate the feasibility of using a micro-laminin gene therapy strategy to deliver gene replacement for MDC1A.
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Affiliation(s)
- Davin Packer
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH, USA
- Center for Gene Therapy, Abigail Wexner Research Institute, The Research Institute at Nationwide Children’s Hospital, Columbus, OH, USA
| | - Paul T. Martin
- Center for Gene Therapy, Abigail Wexner Research Institute, The Research Institute at Nationwide Children’s Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
- Corresponding author Paul T. Martin, Center for Gene Therapy, Abigail Wexner Research Institute, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43209, USA.
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Noël G, Tham DKL, Guadagno E, MacVicar B, Moukhles H. The Laminin-Induced Phosphorylation of PKCδ Regulates AQP4 Distribution and Water Permeability in Rat Astrocytes. Cell Mol Neurobiol 2020; 41:1743-1757. [PMID: 32851539 DOI: 10.1007/s10571-020-00944-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/14/2020] [Indexed: 11/29/2022]
Abstract
In astrocytes, the water-permeable channel aquaporin-4 (AQP4) is concentrated at the endfeet that abut the blood vessels of the brain. The asymmetric distribution of this channel is dependent on the function of dystroglycan (DG), a co-expressed laminin receptor, and its associated protein complex. We have demonstrated that the addition of laminin to astrocytes in culture causes the clustering of AQP4, DG, and lipid rafts. The last, in particular, have been associated with the initiation of cell signaling. As laminin binding to DG in muscle cells can induce the tyrosine phosphorylation of syntrophin and laminin requires tyrosine kinases for acetylcholine receptor clustering in myotubes, we asked if signal transduction might also be involved in AQP4 clustering in astrocytes. We analyzed the timecourse of AQP4, DG, and monosialotetrahexosylganglioside (GM1) clustering in primary cultures of rat astrocytes following the addition of laminin, and determined that the clustering of DG precedes that of AQP4 and GM1. We also showed that laminin induces the formation of phosphotyrosine-rich clusters and that the tyrosine kinase inhibitor, genistein, disrupts the laminin-induced clustering of both β-DG and AQP4. Using the Kinexus antibody microarray chip, we then identified protein-serine kinase C delta (PKCδ) as one of the main proteins exhibiting high levels of tyrosine phosphorylation upon laminin treatment. Selective inhibitors of PKC and siRNA against PKCδ disrupted β-DG and AQP4 clustering, and also caused water transport to increase in astrocytes treated with laminin. Our results demonstrate that the effects of laminin on AQP4 localization and function are relayed, at least in part, through PKC signaling.
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Affiliation(s)
- Geoffroy Noël
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Daniel Kai Long Tham
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Eric Guadagno
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Brian MacVicar
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, V6T 1Z3, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada.
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Liu Y, Yu M, Shang X, Nguyen MHH, Balakrishnan S, Sager R, Hu H. Eyes shut homolog (EYS) interacts with matriglycan of O-mannosyl glycans whose deficiency results in EYS mislocalization and degeneration of photoreceptors. Sci Rep 2020; 10:7795. [PMID: 32385361 PMCID: PMC7210881 DOI: 10.1038/s41598-020-64752-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 04/21/2020] [Indexed: 12/12/2022] Open
Abstract
Mutations in eyes shut homolog (EYS), a secreted extracellular matrix protein containing multiple laminin globular (LG) domains, and in protein O-mannose β1, 2-N-acetylglucosaminyl transferase 1 (POMGnT1), an enzyme involved in O-mannosyl glycosylation, cause retinitis pigmentosa (RP), RP25 and RP76, respectively. How EYS and POMGnT1 regulate photoreceptor survival is poorly understood. Since some LG domain-containing proteins function by binding to the matriglycan moiety of O-mannosyl glycans, we hypothesized that EYS interacted with matriglycans as well. To test this hypothesis, we performed EYS Far-Western blotting assay and generated pomgnt1 mutant zebrafish. The results showed that EYS bound to matriglycans. Pomgnt1 mutation in zebrafish resulted in a loss of matriglycan, retention of synaptotagmin-1-positive EYS secretory vesicles within the outer nuclear layer, and diminished EYS protein near the connecting cilia. Photoreceptor density in 2-month old pomgnt1 mutant retina was similar to the wild-type animals but was significantly reduced at 6-months. These results indicate that EYS protein localization to the connecting cilia requires interaction with the matriglycan and that O-mannosyl glycosylation is required for photoreceptor survival in zebrafish. This study identified a novel interaction between EYS and matriglycan demonstrating that RP25 and RP76 are mechanistically linked in that O-mannosyl glycosylation controls targeting of EYS protein.
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Affiliation(s)
- Yu Liu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Miao Yu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Xuanze Shang
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - My Hong Hoai Nguyen
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
- Department of Biological Sciences, State University of New York at Plattsburgh, 101 Broad St., Plattsburgh, New York, 12901, USA
| | - Shanmuganathan Balakrishnan
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Rachel Sager
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Huaiyu Hu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA.
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8
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Yurchenco PD, McKee KK. Linker Protein Repair of LAMA2 Dystrophic Neuromuscular Basement Membranes. Front Mol Neurosci 2019; 12:305. [PMID: 31920536 PMCID: PMC6923227 DOI: 10.3389/fnmol.2019.00305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/26/2019] [Indexed: 12/18/2022] Open
Abstract
An understanding of basement membrane (BM) assembly at a molecular level provides a foundation with which to develop repair strategies for diseases with defects of BM structure. As currently understood, laminins become anchored to cell surfaces through receptor-mediated interactions and polymerize. This provisional matrix binds to proteoglycans, nidogens and type IV collagen to form a mature BM. Identification of BM binding domains and their binding targets has enabled investigators to engineer proteins that link BM components to modify and improve their functions. This approach is illustrated by the development of two linker proteins to repair the LAMA2-deficient muscular dystrophy (LAMA2-MD). Dystrophy-causing mutations of the LAMA2 gene product (Lmα2) disrupt the BM molecular architecture, destabilizing it. In a mild ambulatory type of the dystrophy, α2LN mutations in laminin-211 prevents polymerization. In the more common and severe non-ambulatory type (MDC1A), an absent Lmα2 subunit is replaced by the naturally occurring Lmα4 subunit that is normally largely confined to the microvasculature. The compensatory laminin, however, is a poor substitute because it neither polymerizes nor binds adequately to the anchoring receptor α-dystroglycan. A chimeric laminin-binding protein called αLNNd enables laminins with defective or absent αLN domains to polymerize while another engineered protein, miniagrin (mag), promotes efficient α-dystroglycan receptor-binding in otherwise weakly adhesive laminins. Alone, αLNNd enables Lm211 with a self-assembly defect to polymerize and was used to ameliorate a mouse model of the ambulatory dystrophy. Together, these linker proteins alter Lm411 such that it both polymerizes and binds αDG such that it properly assembles. This combination was used to ameliorate a mouse model of the non-ambulatory dystrophy in which Lm411 replaced Lm211 as seen in the human disease. Collectively, these studies pave the way for the development of somatic gene delivery of repair proteins for treatment of LAMA2-MD. The studies further suggest a more general approach of linker-protein mediated repair in which a variety of existing BM protein domains can be combined together to stabilize BMs in other diseases.
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Affiliation(s)
- Peter D Yurchenco
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Karen K McKee
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
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Hall TE, Wood AJ, Ehrlich O, Li M, Sonntag CS, Cole NJ, Huttner IG, Sztal TE, Currie PD. Cellular rescue in a zebrafish model of congenital muscular dystrophy type 1A. NPJ Regen Med 2019; 4:21. [PMID: 31754462 PMCID: PMC6858319 DOI: 10.1038/s41536-019-0084-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 10/11/2019] [Indexed: 01/11/2023] Open
Abstract
Laminins comprise structural components of basement membranes, critical in the regulation of differentiation, survival and migration of a diverse range of cell types, including skeletal muscle. Mutations in one muscle enriched Laminin isoform, Laminin alpha2 (Lama2), results in the most common form of congenital muscular dystrophy, congenital muscular dystrophy type 1A (MDC1A). However, the exact cellular mechanism by which Laminin loss results in the pathological spectrum associated with MDC1A remains elusive. Here we show, via live tracking of individual muscle fibres, that dystrophic myofibres in the zebrafish model of MDC1A maintain sarcolemmal integrity and undergo dynamic remodelling behaviours post detachment, including focal sarcolemmal reattachment, cell extension and hyper-fusion with surrounding myoblasts. These observations imply the existence of a window of therapeutic opportunity, where detached cells may be “re-functionalised” prior to their delayed entry into the cell death program, a process we show can be achieved by muscle specific or systemic Laminin delivery. We further reveal that Laminin also acts as a pro-regenerative factor that stimulates muscle stem cell-mediated repair in lama2-deficient animals in vivo. The potential multi-mode of action of Laminin replacement therapy suggests it may provide a potent therapeutic axis for the treatment for MDC1A.
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Affiliation(s)
- T E Hall
- 1Australian Regenerative Medicine Institute, Monash University, Level 1, 15 Innovation Walk, Victoria, 3800 Australia.,2Institute for Molecular Bioscience, University of Queensland, 306 Carmody Road, St Lucia, 4067 Australia
| | - A J Wood
- 1Australian Regenerative Medicine Institute, Monash University, Level 1, 15 Innovation Walk, Victoria, 3800 Australia
| | - O Ehrlich
- 1Australian Regenerative Medicine Institute, Monash University, Level 1, 15 Innovation Walk, Victoria, 3800 Australia
| | - M Li
- 1Australian Regenerative Medicine Institute, Monash University, Level 1, 15 Innovation Walk, Victoria, 3800 Australia
| | - C S Sonntag
- 1Australian Regenerative Medicine Institute, Monash University, Level 1, 15 Innovation Walk, Victoria, 3800 Australia
| | - N J Cole
- 3Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, Sydney, New South Wales 2010 Australia.,4Anatomy & Histology, School of Medical Science, Anderson Stuart Building, Eastern Avenue, The University of Sydney, Sydney, New South Wales 2006 Australia
| | - I G Huttner
- 3Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, Sydney, New South Wales 2010 Australia
| | - T E Sztal
- 1Australian Regenerative Medicine Institute, Monash University, Level 1, 15 Innovation Walk, Victoria, 3800 Australia.,5Department of Biological Sciences, Monash University, Victoria, 3800 Australia
| | - P D Currie
- 1Australian Regenerative Medicine Institute, Monash University, Level 1, 15 Innovation Walk, Victoria, 3800 Australia.,6EMBL Australia, Victorian Node, Monash University, Clayton, VIC 3800 Australia
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Hinou H, Kikuchi S, Ochi R, Igarashi K, Takada W, Nishimura SI. Synthetic glycopeptides reveal specific binding pattern and conformational change at O-mannosylated position of α-dystroglycan by POMGnT1 catalyzed GlcNAc modification. Bioorg Med Chem 2019; 27:2822-2831. [PMID: 31079966 DOI: 10.1016/j.bmc.2019.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/03/2019] [Accepted: 05/05/2019] [Indexed: 01/06/2023]
Abstract
Structural and functional effects of core M1 type glycan modification catalyzed by protein O-linked mannose β1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) were investigated using a core M1 glycoform focused library of an α-dystroglycan fragment, 372TRGAIIQTPTLGPIQPTRV390. Evanescent-field fluorescence-assisted microarray system illuminated the specific binding pattern of plant lectins that can discriminate the glycan structure of core M1 glycan of the library. The comparative NMR analysis of synthetic glycopeptide having different length of the O-mannosylated glycans revealed a conformational change of the peptide backbone along with core M1 disaccharide formation. No long-range NOE signals of glycan-amino acid nor inter amino acid indicate the conformational change is induced by steric hindrance of core M1, the sole 1,2-O-modified form among protein binding sugar residue found in mammals.
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Affiliation(s)
- Hiroshi Hinou
- Graduate School of Life Science, Frontier Research Center for Advanced Material & Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan; Medicinal Chemistry Pharmaceuticals Co. Ltd., Sapporo, Japan.
| | - Seiya Kikuchi
- Graduate School of Life Science, Frontier Research Center for Advanced Material & Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan
| | - Rika Ochi
- Graduate School of Life Science, Frontier Research Center for Advanced Material & Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan
| | | | | | - Shin-Ichiro Nishimura
- Graduate School of Life Science, Frontier Research Center for Advanced Material & Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan; Medicinal Chemistry Pharmaceuticals Co. Ltd., Sapporo, Japan
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11
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Hohenester E. Laminin G-like domains: dystroglycan-specific lectins. Curr Opin Struct Biol 2018; 56:56-63. [PMID: 30530204 DOI: 10.1016/j.sbi.2018.11.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/23/2018] [Accepted: 11/23/2018] [Indexed: 01/31/2023]
Abstract
A unique O-mannose-linked glycan on the transmembrane protein dystroglycan binds a number of extracellular matrix proteins containing laminin G-like (LG) domains. The dystroglycan-matrix interaction is essential for muscle function: disrupted biosynthesis of the matrix-binding modification causes several forms of muscular dystrophy. The complete chemical structure of this modification has been deciphered in the past few years. We now know that LG domains bind to a glycosaminoglycan-like polysaccharide of [-3GlcAβ1,3Xylα1-] units, termed matriglycan, that is attached to a highly unusual heptasaccharide linker. X-ray crystallography has revealed the principles of Ca2+-dependent matriglycan binding by LG domains. In this review, the new structural insights are applied to the growing number of LG domain-containing proteins that bind dystroglycan. It is proposed that LG domains be recognised as 'D-type' lectins to indicate their conserved function in dystroglycan binding.
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Affiliation(s)
- Erhard Hohenester
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom.
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Matlin KS, Myllymäki SM, Manninen A. Laminins in Epithelial Cell Polarization: Old Questions in Search of New Answers. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a027920. [PMID: 28159878 DOI: 10.1101/cshperspect.a027920] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Laminin, a basement membrane protein discovered in 1979, was shortly thereafter implicated in the polarization of epithelial cells in both mammals and a variety of lower organisms. To transduce a spatial cue to the intrinsic polarization machinery, laminin must polymerize into a dense network that forms the foundation of the basement membrane. Evidence suggests that activation of the small GTPase Rac1 by β1-integrins mobilizes laminin-binding integrins and dystroglycan to consolidate formation of the laminin network and initiate rearrangements of both the actin and microtubule cytoskeleton to help establish the apicobasal axis. A key coordinator of spatial signals from laminin is the serine-threonine kinase Par-1, which is known to affect dystroglycan availability, microtubule and actin organization, and lumen formation. The signaling protein integrin-linked kinase (ILK) may also play a role. Despite significant advances, knowledge of the mechanism by which assembled laminin produces a spatial signal remains fragmentary, and much more research into the complex functions of laminin in polarization and other cellular processes is needed.
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Affiliation(s)
- Karl S Matlin
- Department of Surgery, The University of Chicago, Chicago, Illinois 60637-1470
| | - Satu-Marja Myllymäki
- Biocenter Oulu, Oulu Center for Cell-Matrix Research, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu 90220, Finland
| | - Aki Manninen
- Biocenter Oulu, Oulu Center for Cell-Matrix Research, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu 90220, Finland
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13
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Bhat HF, Mir SS, Dar KB, Bhat ZF, Shah RA, Ganai NA. ABC of multifaceted dystrophin glycoprotein complex (DGC). J Cell Physiol 2017; 233:5142-5159. [DOI: 10.1002/jcp.25982] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 05/01/2017] [Indexed: 01/16/2023]
Affiliation(s)
- Hina F. Bhat
- Division of BiotechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Kashmir SKUAST‐KShuhama, SrinagarJammu and KashmirIndia
| | - Saima S. Mir
- Department of BiotechnologyUniversity of KashmirHazratbal, SrinagarJammu and KashmirIndia
| | - Khalid B. Dar
- Department of BiochemistryUniversity of KashmirHazratbal, SrinagarJammu and KashmirIndia
| | - Zuhaib F. Bhat
- Division of Livestock Products and TechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Jammu (SKUAST‐J), R.S. PoraJammuJammu and KashmirIndia
| | - Riaz A. Shah
- Division of BiotechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Kashmir SKUAST‐KShuhama, SrinagarJammu and KashmirIndia
| | - Nazir A. Ganai
- Division of BiotechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Kashmir SKUAST‐KShuhama, SrinagarJammu and KashmirIndia
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14
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Vezina-Audette R, Tremblay M, Carbonetto S. Laminin is instructive and calmodulin dependent kinase II is non-permissive for the formation of complex aggregates of acetylcholine receptors on myotubes in culture. Matrix Biol 2016; 57-58:106-123. [PMID: 27964993 DOI: 10.1016/j.matbio.2016.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/16/2016] [Indexed: 12/11/2022]
Abstract
Previous work has shown that myotubes cultured on laminin-coated substrates form complex aggregates of synaptic proteins that are similar in shape and composition to neuromuscular junctions (NMJs). Here we show that laminin instructs the location of complex aggregates which form only on the lower surface when laminin is coated onto culture dishes but over the entire cell when laminin is added in solution. Silencing of myotubes by agents that block electrical activity (tetrodotoxin, verapamil) or by inhibitors of calmodulin dependent kinase (CaMKII) render the myotube permissive for the formation of complex aggregates. Treatment with laminin alone will facilitate the formation of complex aggregates hours later when myotubes are made permissive by inhibiting CaMKII. The AChR agonist carbachol disperses pre formed aggregates suggesting that non-permissiveness may involve active dispersal of AChRs. The permissive period requires ongoing protein synthesis. The latter may reflect a requirement for rapsyn, which turns over rapidly, and is necessary for aggregation. Consistent with this geldanamycin, an agent that increases rapsyn turnover disrupts complex aggregates. Agrin is well known to induce small clusters of AChRs but does not induce complex aggregates even though aggregate formation requires MuSK, a receptor tyrosine kinase activated by agrin. Dystroglycan (DG) is the major laminin receptor mediating complex aggregate formation with some contribution from β1 integrins. In addition, there is a pool of CaMKII associated with DG. We discuss how these permissive and instructive mechanisms bear on NMJ formation in vivo.
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Affiliation(s)
- Raphael Vezina-Audette
- Centre for Research in Neuroscience, and Dept. of Neurology, McGill University Health Centre, 1650, Cedar Ave., Montreal, Quebec, H3G 1A4, Canada
| | - Mathieu Tremblay
- Centre for Research in Neuroscience, and Dept. of Neurology, McGill University Health Centre, 1650, Cedar Ave., Montreal, Quebec, H3G 1A4, Canada
| | - Salvatore Carbonetto
- Centre for Research in Neuroscience, and Dept. of Neurology, McGill University Health Centre, 1650, Cedar Ave., Montreal, Quebec, H3G 1A4, Canada.
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15
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Postnatal Gene Therapy Improves Spatial Learning Despite the Presence of Neuronal Ectopia in a Model of Neuronal Migration Disorder. Genes (Basel) 2016; 7:genes7120105. [PMID: 27916859 PMCID: PMC5192481 DOI: 10.3390/genes7120105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/17/2016] [Accepted: 11/19/2016] [Indexed: 11/25/2022] Open
Abstract
Patients with type II lissencephaly, a neuronal migration disorder with ectopic neurons, suffer from severe mental retardation, including learning deficits. There is no effective therapy to prevent or correct the formation of neuronal ectopia, which is presumed to cause cognitive deficits. We hypothesized that learning deficits were not solely caused by neuronal ectopia and that postnatal gene therapy could improve learning without correcting the neuronal ectopia formed during fetal development. To test this hypothesis, we evaluated spatial learning of cerebral cortex-specific protein O-mannosyltransferase 2 (POMT2, an enzyme required for O-mannosyl glycosylation) knockout mice and compared to the knockout mice that were injected with an adeno-associated viral vector (AAV) encoding POMT2 into the postnatal brains with Barnes maze. The data showed that the knockout mice exhibited reduced glycosylation in the cerebral cortex, reduced dendritic spine density on CA1 neurons, and increased latency to the target hole in the Barnes maze, indicating learning deficits. Postnatal gene therapy restored functional glycosylation, rescued dendritic spine defects, and improved performance on the Barnes maze by the knockout mice even though neuronal ectopia was not corrected. These results indicate that postnatal gene therapy improves spatial learning despite the presence of neuronal ectopia.
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16
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Rogers RS, Nishimune H. The role of laminins in the organization and function of neuromuscular junctions. Matrix Biol 2016; 57-58:86-105. [PMID: 27614294 DOI: 10.1016/j.matbio.2016.08.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 08/10/2016] [Accepted: 08/17/2016] [Indexed: 01/11/2023]
Abstract
The synapse between motor neurons and skeletal muscle is known as the neuromuscular junction (NMJ). Proper alignment of presynaptic and post-synaptic structures of motor neurons and muscle fibers, respectively, is essential for efficient motor control of skeletal muscles. The synaptic cleft between these two cells is filled with basal lamina. Laminins are heterotrimer extracellular matrix molecules that are key members of the basal lamina. Laminin α4, α5, and β2 chains specifically localize to NMJs, and these laminin isoforms play a critical role in maintenance of NMJs and organization of synaptic vesicle release sites known as active zones. These individual laminin chains exert their role in organizing NMJs by binding to their receptors including integrins, dystroglycan, and voltage-gated calcium channels (VGCCs). Disruption of these laminins or the laminin-receptor interaction occurs in neuromuscular diseases including Pierson syndrome and Lambert-Eaton myasthenic syndrome (LEMS). Interventions to maintain proper level of laminins and their receptor interactions may be insightful in treating neuromuscular diseases and aging related degeneration of NMJs.
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Affiliation(s)
- Robert S Rogers
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, Kansas, USA.
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, Kansas, USA.
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17
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de Fátima MenegociEugênio P, Assunção NA, Sciandra F, Aquino A, Brancaccio A, Carrilho E. Quantification, 2DE analysis and identification of enriched glycosylated proteins from mouse muscles: Difficulties and alternatives. Electrophoresis 2015; 37:321-34. [PMID: 26542084 DOI: 10.1002/elps.201500362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 08/02/2015] [Accepted: 10/22/2015] [Indexed: 11/11/2022]
Abstract
One of the problems with 2DE is that proteins present in low amounts in a sample are usually not detected, since their signals are masked by the predominant proteins. The elimination of these abundant proteins is not a guaranteed solution to achieve the desired results. The main objective of this study was the comparison of common and simple methodologies employed for 2DE analysis followed by MS identification, focusing on a pre-purified sample using a wheat germ agglutinin (WGA) column. Adult male C57Black/Crj6 (C57BL/6) mice were chosen as the model animal in this study; the gastrocnemius muscles were collected and processed for the experiments. The initial fractionation with succinylated WGA was successful for the elimination of the most abundant proteins. Two quantification methods were employed for the purified samples, and bicinchoninic acid (BCA) was proven to be most reliable for the quantification of glycoproteins. The gel staining method, however, was found to be decisive for the detection of specific proteins, since their structures affect the interaction of the dye with the peptide backbone. The Coomassie Blue R-250 dye very weakly stained the gel with the WGA purified sample. When the same gel was stained with silver nitrate, however, MS could positively assign 12 new spots. The structure of the referred proteins was not found to be prone to interaction with Coomassie blue.
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Affiliation(s)
- Patrícia de Fátima MenegociEugênio
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP, Brazil
| | - Nilson Antonio Assunção
- Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brazil
| | - Francesca Sciandra
- Istituto di Chimica del Riconoscimento Molecolare (CNR), c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Adriano Aquino
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP, Brazil
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento Molecolare (CNR), c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Emanuel Carrilho
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP, Brazil
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18
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Yurchenco PD. Integrating Activities of Laminins that Drive Basement Membrane Assembly and Function. CURRENT TOPICS IN MEMBRANES 2015; 76:1-30. [PMID: 26610910 DOI: 10.1016/bs.ctm.2015.05.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Studies on extracellular matrix proteins, cells, and genetically modified animals have converged to reveal mechanisms of basement membrane self-assembly as mediated by γ1 subunit-containing laminins, the focus of this chapter. The basic model is as follows: A member of the laminin family adheres to a competent cell surface and typically polymerizes followed by laminin binding to the extracellular adaptor proteins nidogen, perlecan, and agrin. Assembly is completed by the linking of nidogen and heparan sulfates to type IV collagen, allowing it to form a second stabilizing network polymer. The assembled matrix provides structural support, anchoring the extracellular matrix to the cytoskeleton, and acts as a signaling platform. Heterogeneity of function is created in part by the isoforms of laminin that vary in their ability to polymerize and to interact with integrins, dystroglycan, and other receptors. Mutations in laminin subunits, affecting expression or LN domain-specific functions, are a cause of human diseases that include those of muscle, nerve, brain, and kidney.
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Affiliation(s)
- Peter D Yurchenco
- Department of Pathology & Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.
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19
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The dystroglycan: Nestled in an adhesome during embryonic development. Dev Biol 2015; 401:132-42. [DOI: 10.1016/j.ydbio.2014.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/23/2014] [Accepted: 07/08/2014] [Indexed: 01/11/2023]
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20
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Levy AD, Omar MH, Koleske AJ. Extracellular matrix control of dendritic spine and synapse structure and plasticity in adulthood. Front Neuroanat 2014; 8:116. [PMID: 25368556 PMCID: PMC4202714 DOI: 10.3389/fnana.2014.00116] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/29/2014] [Indexed: 12/20/2022] Open
Abstract
Dendritic spines are the receptive contacts at most excitatory synapses in the central nervous system. Spines are dynamic in the developing brain, changing shape as they mature as well as appearing and disappearing as they make and break connections. Spines become much more stable in adulthood, and spine structure must be actively maintained to support established circuit function. At the same time, adult spines must retain some plasticity so their structure can be modified by activity and experience. As such, the regulation of spine stability and remodeling in the adult animal is critical for normal function, and disruption of these processes is associated with a variety of late onset diseases including schizophrenia and Alzheimer's disease. The extracellular matrix (ECM), composed of a meshwork of proteins and proteoglycans, is a critical regulator of spine and synapse stability and plasticity. While the role of ECM receptors in spine regulation has been extensively studied, considerably less research has focused directly on the role of specific ECM ligands. Here, we review the evidence for a role of several brain ECM ligands and remodeling proteases in the regulation of dendritic spine and synapse formation, plasticity, and stability in adults.
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Affiliation(s)
- Aaron D Levy
- Interdepartmental Neuroscience Program, Yale University New Haven, CT, USA ; Department of Molecular Biophysics and Biochemistry, Yale University New Haven, CT, USA
| | - Mitchell H Omar
- Interdepartmental Neuroscience Program, Yale University New Haven, CT, USA ; Department of Molecular Biophysics and Biochemistry, Yale University New Haven, CT, USA
| | - Anthony J Koleske
- Interdepartmental Neuroscience Program, Yale University New Haven, CT, USA ; Department of Molecular Biophysics and Biochemistry, Yale University New Haven, CT, USA ; Department of Neurobiology, Yale University New Haven, CT, USA
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21
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Reissner C, Stahn J, Breuer D, Klose M, Pohlentz G, Mormann M, Missler M. Dystroglycan binding to α-neurexin competes with neurexophilin-1 and neuroligin in the brain. J Biol Chem 2014; 289:27585-603. [PMID: 25157101 PMCID: PMC4183798 DOI: 10.1074/jbc.m114.595413] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
α-Neurexins (α-Nrxn) are mostly presynaptic cell surface molecules essential for neurotransmission that are linked to neuro-developmental disorders as autism or schizophrenia. Several interaction partners of α-Nrxn are identified that depend on alternative splicing, including neuroligins (Nlgn) and dystroglycan (αDAG). The trans-synaptic complex with Nlgn1 was extensively characterized and shown to partially mediate α-Nrxn function. However, the interactions of α-Nrxn with αDAG, neurexophilins (Nxph1) and Nlgn2, ligands that occur specifically at inhibitory synapses, are incompletely understood. Using site-directed mutagenesis, we demonstrate the exact binding epitopes of αDAG and Nxph1 on Nrxn1α and show that their binding is mutually exclusive. Identification of an unusual cysteine bridge pattern and complex type glycans in Nxph1 ensure binding to the second laminin/neurexin/sex hormone binding (LNS2) domain of Nrxn1α, but this association does not interfere with Nlgn binding at LNS6. αDAG, in contrast, interacts with both LNS2 and LNS6 domains without inserts in splice sites SS#2 or SS#4 mostly via LARGE (like-acetylglucosaminyltransferase)-dependent glycans attached to the mucin region. Unexpectedly, binding of αDAG at LNS2 prevents interaction of Nlgn at LNS6 with or without splice insert in SS#4, presumably by sterically hindering each other in the u-form conformation of α-Nrxn. Thus, expression of αDAG and Nxph1 together with alternative splicing in Nrxn1α may prevent or facilitate formation of distinct trans-synaptic Nrxn·Nlgn complexes, revealing an unanticipated way to contribute to the identity of synaptic subpopulations.
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Affiliation(s)
- Carsten Reissner
- From the Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Vesaliusweg 2-4, 48149 Münster, Germany
| | - Johanna Stahn
- From the Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Vesaliusweg 2-4, 48149 Münster, Germany
| | - Dorothee Breuer
- From the Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Vesaliusweg 2-4, 48149 Münster, Germany
| | - Martin Klose
- From the Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Vesaliusweg 2-4, 48149 Münster, Germany
| | - Gottfried Pohlentz
- Institute of Medical Physics and Biophysics, Westfälische Wilhelms-University, Robert-Koch Strasse 31, 48149 Münster, Germany, and
| | - Michael Mormann
- Institute of Medical Physics and Biophysics, Westfälische Wilhelms-University, Robert-Koch Strasse 31, 48149 Münster, Germany, and
| | - Markus Missler
- From the Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Vesaliusweg 2-4, 48149 Münster, Germany, Cluster of Excellence EXC 1003, Cells in Motion, 48149 Münster, Germany
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22
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Stawarski M, Stefaniuk M, Wlodarczyk J. Matrix metalloproteinase-9 involvement in the structural plasticity of dendritic spines. Front Neuroanat 2014; 8:68. [PMID: 25071472 PMCID: PMC4091410 DOI: 10.3389/fnana.2014.00068] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 06/25/2014] [Indexed: 01/01/2023] Open
Abstract
Dendritic spines are the locus for excitatory synaptic transmission in the brain and thus play a major role in neuronal plasticity. The ability to alter synaptic connections includes volumetric changes in dendritic spines that are driven by scaffolds created by the extracellular matrix (ECM). Here, we review the effects of the proteolytic activity of ECM proteases in physiological and pathological structural plasticity. We use matrix metalloproteinase-9 (MMP-9) as an example of an ECM modifier that has recently emerged as a key molecule in regulating the morphology and dysmorphology of dendritic spines that underlie synaptic plasticity and neurological disorders, respectively. We summarize the influence of MMP-9 on the dynamic remodeling of the ECM via the cleavage of extracellular substrates. We discuss its role in the formation, modification, and maintenance of dendritic spines in learning and memory. Finally, we review research that implicates MMP-9 in aberrant synaptic plasticity and spine dysmorphology in neurological disorders, with a focus on morphological abnormalities of dendritic protrusions that are associated with epilepsy.
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Affiliation(s)
- Michal Stawarski
- Laboratory of Cell Biophysics, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology Warsaw, Mazowieckie, Poland
| | - Marzena Stefaniuk
- Laboratory of Neurobiology, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology Warsaw, Mzowieckie, Poland
| | - Jakub Wlodarczyk
- Laboratory of Cell Biophysics, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology Warsaw, Mazowieckie, Poland
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23
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Lennon R, Randles MJ, Humphries MJ. The importance of podocyte adhesion for a healthy glomerulus. Front Endocrinol (Lausanne) 2014; 5:160. [PMID: 25352829 PMCID: PMC4196579 DOI: 10.3389/fendo.2014.00160] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/21/2014] [Indexed: 12/23/2022] Open
Abstract
Podocytes are specialized epithelial cells that cover the outer surfaces of glomerular capillaries. Unique cell junctions, known as slit diaphragms, which feature nephrin and Neph family proteins in addition to components of adherens, tight, and gap junctions, connect adjacent podocyte foot processes. Single gene disorders affecting the slit diaphragm result in nephrotic syndrome in humans, characterized by massive loss of protein across the capillary wall. In addition to specialized cell junctions, interconnecting podocytes also adhere to the glomerular basement membrane (GBM) of the capillary wall. The GBM is a dense network of secreted, extracellular matrix (ECM) components and contains tissue-restricted isoforms of collagen IV and laminin in addition to other structural proteins and ECM regulators such as proteases and growth factors. The specialized niche of the GBM provides a scaffold for endothelial cells and podocytes to support their unique functions and human genetic mutations in GBM components lead to renal failure, thus highlighting the importance of cell-matrix interactions in the glomerulus. Cells adhere to ECM via adhesion receptors, including integrins, syndecans, and dystroglycan and in particular the integrin heterodimer α3β1 is required to maintain barrier integrity. Therefore, the sophisticated function of glomerular filtration relies on podocyte adhesion both at cell junctions and at the interface with the ECM. In health, the podocyte coordinates signals from cell junctions and cell-matrix interactions, in response to environmental cues in order to regulate filtration and as our understanding of mechanisms that control cell adhesion in the glomerulus develops, then insight into the effects of disease will improve. The ultimate goal will be to develop targeted therapies to prevent or repair defects in the filtration barrier and to restore glomerular function.
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Affiliation(s)
- Rachel Lennon
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
- Institute of Human Development, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK
- Department of Paediatric Nephrology, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
- *Correspondence: Rachel Lennon, Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Michael Smith Building, Manchester M13 9PT, UK e-mail:
| | - Michael J. Randles
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
- Institute of Human Development, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK
| | - Martin J. Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
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24
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Sharpe KM, Premsukh MD, Townsend D. Alterations of dystrophin-associated glycoproteins in the heart lacking dystrophin or dystrophin and utrophin. J Muscle Res Cell Motil 2013; 34:395-405. [PMID: 24096570 DOI: 10.1007/s10974-013-9362-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/26/2013] [Indexed: 11/26/2022]
Abstract
Heart disease is a leading cause of death in patients with Duchenne muscular dystrophy (DMD). Patients with DMD lack the protein dystrophin, which is widely expressed in striated muscle. In skeletal muscle, the loss of dystrophin results in dramatically decreased expression of the dystrophin associated glycoprotein complex (DGC). Interestingly, in the heart the DGC is normally expressed without dystrophin; this has been attributed to presence of the dystrophin homologue utrophin. We demonstrate here that neither utrophin nor dystrophin are required for the expression of the cardiac DGC. However, alpha-dystroglycan (α-DG), a major component of the DGC, is differentially glycosylated in dystrophin-(mdx) and dystrophin-/utrophin-(dko) deficient mouse hearts. In both models the altered α-DG retains laminin binding activity, but has an altered localization at the sarcolemma. In hearts lacking both dystrophin and utrophin, the alterations in α-DG glycosylation are even more dramatic with changes in gel migration equivalent to 24 ± 3 kDa. These data show that the absence of dystrophin and utrophin alters the processing of α-DG; however it is not clear if these alterations are a consequence of the loss of a direct interaction with dystrophin/utrophin or results from an indirect response to the presence of severe pathology. Recently there have been great advances in our understanding of the glycosylation of α-DG regarding its role as a laminin receptor. Here we present data that alterations in glycosylation occur in the hearts of animal models of DMD, but these changes do not affect laminin binding. The physiological consequences of these alterations remain unknown, but may have significant implications for the development of therapies for DMD.
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Affiliation(s)
- Katharine M Sharpe
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
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25
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Yu M, He Y, Wang K, Zhang P, Zhang S, Hu H. Adeno-associated viral-mediated LARGE gene therapy rescues the muscular dystrophic phenotype in mouse models of dystroglycanopathy. Hum Gene Ther 2013; 24:317-30. [PMID: 23379513 DOI: 10.1089/hum.2012.084] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Dystroglycanopathies are a group of congenital muscular dystrophies (CMD) often caused by mutations in genes encoding glycosyltransferases that lead to hypoglycosylation of α-dystroglycan (α-DG) and reduce its extracellular matrix-binding activity. Overexpressing LARGE (formerly known as like-glycosyltransferase) generates an extracellular matrix-binding carbohydrate epitope in cells with CMD-causing mutations in not only LARGE but also other glycosyltransferases, including POMT1, POMGnT1, and fukutin, creating the possibilities of a one-for-all gene therapy. To determine the feasibility of LARGE gene therapy, a serotype 9 adeno-associated viral vector for overexpressing LARGE (AAV9-LARGE) was injected intracardially into newborns of two mouse models of CMD: the natural LARGE mutant Large(myd) mice and protein O-mannose N-acetylglucosaminyltransferase 1 (POMGnT1) knockout mice. AAV9-LARGE virus treatment yielded partial restoration of α-DG glycosylation and ligand-binding activity. The muscular dystrophy phenotype in skeletal muscles was ameliorated as revealed by significantly reduced fibrosis, necrosis, and numbers of centrally located nuclei with improved motor function. These results indicate that LARGE overexpression in vivo by AAV9-mediated gene therapy is effective at restoring functional glycosylation of α-DG and rescuing the muscular dystrophy phenotype in deficiency of not only LARGE but also POMGnT1, providing evidence that in vivo LARGE gene therapy may be broadly useful in dystroglycanopathies.
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Affiliation(s)
- Miao Yu
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY 13210, USA
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26
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Johnson EK, Li B, Yoon JH, Flanigan KM, Martin PT, Ervasti J, Montanaro F. Identification of new dystroglycan complexes in skeletal muscle. PLoS One 2013; 8:e73224. [PMID: 23951345 PMCID: PMC3738564 DOI: 10.1371/journal.pone.0073224] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/18/2013] [Indexed: 01/16/2023] Open
Abstract
The dystroglycan complex contains the transmembrane protein β-dystroglycan and its interacting extracellular mucin-like protein α-dystroglycan. In skeletal muscle fibers, the dystroglycan complex plays an important structural role by linking the cytoskeletal protein dystrophin to laminin in the extracellular matrix. Mutations that affect any of the proteins involved in this structural axis lead to myofiber degeneration and are associated with muscular dystrophies and congenital myopathies. Because loss of dystrophin in Duchenne muscular dystrophy (DMD) leads to an almost complete loss of dystroglycan complexes at the myofiber membrane, it is generally assumed that the vast majority of dystroglycan complexes within skeletal muscle fibers interact with dystrophin. The residual dystroglycan present in dystrophin-deficient muscle is thought to be preserved by utrophin, a structural homolog of dystrophin that is up-regulated in dystrophic muscles. However, we found that dystroglycan complexes are still present at the myofiber membrane in the absence of both dystrophin and utrophin. Our data show that only a minority of dystroglycan complexes associate with dystrophin in wild type muscle. Furthermore, we provide evidence for at least three separate pools of dystroglycan complexes within myofibers that differ in composition and are differentially affected by loss of dystrophin. Our findings indicate a more complex role of dystroglycan in muscle than currently recognized and may help explain differences in disease pathology and severity among myopathies linked to mutations in DAPC members.
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Affiliation(s)
- Eric K. Johnson
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Ohio State Biochemistry Program, the Ohio State University, Columbus, Ohio, United States of America
| | - Bin Li
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Jung Hae Yoon
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
| | - Kevin M. Flanigan
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Department of Pediatrics, the Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Paul T. Martin
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Department of Pediatrics, the Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - James Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Federica Montanaro
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Ohio State Biochemistry Program, the Ohio State University, Columbus, Ohio, United States of America
- Department of Pediatrics, the Ohio State University College of Medicine, Columbus, Ohio, United States of America
- * E-mail:
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Zhang P, Yang Y, Candiello J, Thorn TL, Gray N, Halfter WM, Hu H. Biochemical and biophysical changes underlie the mechanisms of basement membrane disruptions in a mouse model of dystroglycanopathy. Matrix Biol 2013; 32:196-207. [PMID: 23454088 DOI: 10.1016/j.matbio.2013.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 01/24/2013] [Accepted: 02/11/2013] [Indexed: 01/11/2023]
Abstract
Mutations in glycosyltransferases, such as protein O-mannose N-acetylglucosaminyltransferase 1 (POMGnT1), causes disruptions of basement membranes (BMs) that results in neuronal ectopias and muscular dystrophy. While the mutations diminish dystroglycan-mediated cell-ECM interactions, the cause and mechanism of BM disruptions remain unclear. In this study, we established an in vitro model to measure BM assembly on the surface of neural stem cells. Compared to control cells, the rate of BM assembly on POMGnT1 knockout neural stem cells was significantly reduced. Further, immunofluorescence staining and quantitative proteomic analysis of the inner limiting membrane (ILM), a BM of the retina, revealed that laminin-111 and nidogen-1 were reduced in POMGnT1 knockout mice. Finally, atomic force microscopy showed that the ILM from POMGnT1 knockout mice was thinner with an altered surface topography. The results combined demonstrate that reduced levels of key BM components cause physical changes that weaken the BM in POMGnT1 knockout mice. These changes are caused by a reduced rate of BM assembly during the developmental expansion of the neural tissue.
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Affiliation(s)
- Peng Zhang
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, USA
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28
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Abstract
The heterotrimeric laminins are a defining component of all basement membranes and self-assemble into a cell-associated network. The three short arms of the cross-shaped laminin molecule form the network nodes, with a strict requirement for one α, one β and one γ arm. The globular domain at the end of the long arm binds to cellular receptors, including integrins, α-dystroglycan, heparan sulfates and sulfated glycolipids. Collateral anchorage of the laminin network is provided by the proteoglycans perlecan and agrin. A second network is then formed by type IV collagen, which interacts with the laminin network through the heparan sulfate chains of perlecan and agrin and additional linkage by nidogen. This maturation of basement membranes becomes essential at later stages of embryo development.
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29
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Beedle AM, Turner AJ, Saito Y, Lueck JD, Foltz SJ, Fortunato MJ, Nienaber PM, Campbell KP. Mouse fukutin deletion impairs dystroglycan processing and recapitulates muscular dystrophy. J Clin Invest 2012; 122:3330-42. [PMID: 22922256 DOI: 10.1172/jci63004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 06/21/2012] [Indexed: 11/17/2022] Open
Abstract
Dystroglycan is a transmembrane glycoprotein that links the extracellular basement membrane to cytoplasmic dystrophin. Disruption of the extensive carbohydrate structure normally present on α-dystroglycan causes an array of congenital and limb girdle muscular dystrophies known as dystroglycanopathies. The essential role of dystroglycan in development has hampered elucidation of the mechanisms underlying dystroglycanopathies. Here, we developed a dystroglycanopathy mouse model using inducible or muscle-specific promoters to conditionally disrupt fukutin (Fktn), a gene required for dystroglycan processing. In conditional Fktn-KO mice, we observed a near absence of functionally glycosylated dystroglycan within 18 days of gene deletion. Twenty-week-old KO mice showed clear dystrophic histopathology and a defect in glycosylation near the dystroglycan O-mannose phosphate, whether onset of Fktn excision driven by muscle-specific promoters occurred at E8 or E17. However, the earlier gene deletion resulted in more severe phenotypes, with a faster onset of damage and weakness, reduced weight and viability, and regenerating fibers of smaller size. The dependence of phenotype severity on the developmental timing of muscle Fktn deletion supports a role for dystroglycan in muscle development or differentiation. Moreover, given that this conditional Fktn-KO mouse allows the generation of tissue- and timing-specific defects in dystroglycan glycosylation, avoids embryonic lethality, and produces a phenotype resembling patient pathology, it is a promising new model for the study of secondary dystroglycanopathy.
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Affiliation(s)
- Aaron M Beedle
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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30
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Steiner E, Enzmann GU, Lin S, Ghavampour S, Hannocks MJ, Zuber B, Rüegg MA, Sorokin L, Engelhardt B. Loss of astrocyte polarization upon transient focal brain ischemia as a possible mechanism to counteract early edema formation. Glia 2012; 60:1646-59. [DOI: 10.1002/glia.22383] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 06/07/2012] [Indexed: 11/10/2022]
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31
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Lee JK, Matthews RT, Lim JM, Swanier K, Wells L, Pierce JM. Developmental expression of the neuron-specific N-acetylglucosaminyltransferase Vb (GnT-Vb/IX) and identification of its in vivo glycan products in comparison with those of its paralog, GnT-V. J Biol Chem 2012; 287:28526-36. [PMID: 22715095 DOI: 10.1074/jbc.m112.367565] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The severe phenotypic effects of altered glycosylation in the congenital muscular dystrophies, including Walker-Warburg syndrome, muscle-eye-brain disease, Fukuyama congenital muscular dystrophy, and congenital muscular dystrophy 1D, are caused by mutations resulting in altered glycans linked to proteins through O-linked mannose. A glycosyltransferase that branches O-Man, N-acetylglucosaminyltransferase Vb (GnT-Vb), is highly expressed in neural tissues. To understand the expression and function of GnT-Vb, we studied its expression during neuromorphogenesis and generated GnT-Vb null mice. A paralog of GnT-Vb, N-acetylglucosaminyltransferase (GnT-V), is expressed in many tissues and brain, synthesizing N-linked, β1,6-branched glycans, but its ability to synthesize O-mannosyl-branched glycans is unknown; conversely, although GnT-Vb can synthesize N-linked glycans in vitro, its contribution to their synthesis in vivo is unknown. Our results showed that deleting both GnT-V and GnT-Vb results in the total loss of both N-linked and O-Man-linked β1,6-branched glycans. GnT-V null brains lacked N-linked, β1,6-glycans but had normal levels of O-Man β1,6-branched structures, showing that GnT-Vb could not compensate for the loss of GnT-V. By contrast, GnT-Vb null brains contained normal levels of N-linked β1,6-glycans but low levels of some O-Man β1,6-branched glycans. Therefore, GnT-V could partially compensate for GnT-Vb activity in vivo. We found no apparent change in α-dystroglycan binding of glycan-specific antibody IIH6C4 or binding to laminin in GnT-Vb null mice. These results demonstrate that GnT-V is involved in synthesizing branched O-mannosyl glycans in brain, but the function of these branched O-mannosyl structures is unresolved using mice that lack these glycosyltransferases.
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Affiliation(s)
- Jin Kyu Lee
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30605, USA
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Zhang P, Hu H. Differential glycosylation of α-dystroglycan and proteins other than α-dystroglycan by like-glycosyltransferase. Glycobiology 2011; 22:235-47. [PMID: 21930648 DOI: 10.1093/glycob/cwr131] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genetic defects in like-glycosyltransferase (LARGE) cause congenital muscular dystrophy with central nervous system manifestations. The underlying molecular pathomechanism is the hypoglycosylation of α-dystroglycan (α-DG), which is evidenced by diminished immunoreactivity to IIH6C4 and VIA4-1, antibodies that recognize carbohydrate epitopes. Previous studies indicate that LARGE participates in the formation of a phosphoryl glycan branch on O-linked mannose or it modifies complex N- and mucin O-glycans. In this study, we overexpressed LARGE in neural stem cells deficient in protein O-mannosyltransferase 2 (POMT2), an enzyme required for O-mannosyl glycosylation. The results showed that overexpressing LARGE did not lead to hyperglycosylation of α-DG in POMT2 knockout (KO) cells but did generate IIH6C4 and VIA4-1 immunoreactivity and laminin-binding activity. Additionally, overexpressing LARGE in cells deficient in both POMT2 and α-DG generated laminin-binding IIH6C4 immunoreactivity. These results indicate that LARGE expression resulted in the glycosylation of proteins other than α-DG in the absence of O-mannosyl glycosylation. The IIH6C4 immunoreactivity generated in double-KO cells was largely removed by treatment either with peptide N-glycosidase F or with cold aqueous hydrofluoric acid, suggesting that LARGE expression caused phosphoryl glycosylation of N-glycans. However, the glycosylation of α-DG by LARGE is dependent on POMT2, indicating that LARGE expression only modifies O-linked mannosyl glycans of α-DG. Thus, LARGE expression mediates the phosphoryl glycosylation of not only O-mannosyl glycans including those on α-DG but also N-glycans on proteins other than α-DG.
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Affiliation(s)
- Peng Zhang
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 750 E. Adams Street, Syracuse, NY 13210, USA
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Parberry-Clark C, Bury JP, Cross SS, Winder SJ. Loss of dystroglycan function in oesophageal cancer. Histopathology 2011; 59:180-7. [DOI: 10.1111/j.1365-2559.2011.03930.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hu H, Li J, Gagen CS, Gray NW, Zhang Z, Qi Y, Zhang P. Conditional knockout of protein O-mannosyltransferase 2 reveals tissue-specific roles of O-mannosyl glycosylation in brain development. J Comp Neurol 2011; 519:1320-37. [PMID: 21452199 DOI: 10.1002/cne.22572] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The meninges produce essential signaling molecules and major protein components of the pial basement membrane during normal brain development. Disruptions in the pial basement membrane underlie neural ectopia seen in those congenital muscular dystrophies (CMDs) caused by mutations in genes involved in O-mannosyl glycosylation. In mammals, biosynthesis of O-mannosyl glycans is initiated by a complex of mutually indispensable protein O-mannosyltransferases 1 and 2 (POMT1 and 2). To study the roles of O-mannosylation in brain development we generated a conditional allele of POMT2. POMT2 nulllizygosity resulted in embryonic lethality because of a defective Reichert's membrane. Brain-specific deletion of POMT2 resulted in hypoglycosylation of α-dystroglycan (DG) and abolished laminin binding activity. The effect of POMT2 deletion on brain development was dependent on timing, as earlier deletion resulted in more severe phenotypes. Multiple brain malformations including overmigration of neocortical neurons and migration failure of granule cells in the cerebellum were observed. Immunofluorescence staining and transmission electron microscopy revealed that these migration defects were closely associated with disruptions in the pial basement membrane. Interestingly, POMT2 deletion in the meninges (and blood vessels) did not disrupt the development of the neocortex. Thus, normal brain development requires protein O-mannosylation activity in neural tissue but not the meninges. These results suggest that gene therapy should be directed to the neural tissue instead of the meninges.
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Affiliation(s)
- Huaiyu Hu
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, New York 13210, USA.
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Tham DKL, Moukhles H. Regulation of Kir4.1 and AQP4 expression and stability at the basolateral domain of epithelial MDCK cells by the extracellular matrix. Am J Physiol Renal Physiol 2011; 301:F396-409. [PMID: 21543416 DOI: 10.1152/ajprenal.00315.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The proper targeting of ion channels to specialized domains is crucial for cell function. Kir4.1, the inwardly rectifying potassium channel, and aquaporin-4 (AQP4), the type 4 water-permeable channel, are localized at the basolateral domain of polarized epithelial cells; however, the mechanisms involved in their localization have yet to be determined. In this study, we investigated the role of the extracellular matrix in the localization of these channels in polarized Madin-Darby canine kidney (MDCK) cells. MDCK cells expressing green fluorescent protein-Kir4.1 or -AQP4 were cultured on laminin-1 or fibronectin and examined by confocal microscopy and cell surface biotinylation to assess plasma membrane expression of Kir4.1 and AQP4. Our data show that laminin-1 and fibronectin induce a significant increase in cell surface expression of both channels at the basolateral domain. Using fluorescence recovery after photobleaching, we demonstrate that laminin-1 and fibronectin reduce the diffusion rates of these channels. Finally, we show that the laminin receptor dystroglycan is important for cell surface expression of Kir4.1 but not AQP4. However, laminin-1 increases cell surface expression of both channels in cells deficient for dystroglycan, indicating that other receptors are involved. Indeed, RGD-containing peptides, which inhibit fibronectin binding to certain integrins, prevent the fibronectin-induced increase in Kir4.1 and AQP4 cell surface expression and reverse the laminin- and fibronectin-induced reduction in both channels' diffusion rates. Similarly, the αvβ3-integrin function-blocking antibody alters the reduction of AQP4 diffusion rates induced by both laminin and fibronectin, suggesting that αvβ3-integrin plays a role in the stabilization of APQ4 at the basolateral domain of epithelial cells.
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Affiliation(s)
- Daniel Kai Long Tham
- Dept of Cellular and Physiological Sciences, Univ. of British Columbia, Vancouver, Canada
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36
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Zhang Z, Zhang P, Hu H. LARGE expression augments the glycosylation of glycoproteins in addition to α-dystroglycan conferring laminin binding. PLoS One 2011; 6:e19080. [PMID: 21533062 PMCID: PMC3080415 DOI: 10.1371/journal.pone.0019080] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Accepted: 03/27/2011] [Indexed: 12/03/2022] Open
Abstract
Mutations in genes encoding glycosyltransferases (and presumed glycosyltransferases) that affect glycosylation and extracellular matrix binding activity of α-dystroglycan (α-DG) cause congenital muscular dystrophies (CMDs) with central nervous system manifestations. Among the identified genes, LARGE is of particular interest because its overexpression rescues glycosylation defects of α-DG in mutations of not only LARGE but also other CMD-causing genes and restores laminin binding activity of α-DG. It is not known whether LARGE protein glycosylates other proteins in addition to α-DG. In this study, we overexpressed LARGE in DG-deficient cells and analyzed glycosylated proteins by Western blot analysis. Surprisingly, overexpression of LARGE in α-DG-deficient cells led to glycosylation dependent IIH6C4 and VIA4-1 immunoreactivity, despite the prevailing view that these antibodies only recognize glycosylated α-DG. Furthermore, the hyperglycosylated proteins in LARGE-overexpressing cells demonstrated the functional capacity to bind the extracellular matrix molecule laminin and promote laminin assembly at the cell surface, an effect that was blocked by IIH6C4 antibodies. These results indicate that overexpression of LARGE catalyzes the glycosylation of at least one other glycoprotein in addition to α-DG, and that this glycosylation(s) promotes laminin binding activity.
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Affiliation(s)
- Zhen Zhang
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, New York, United States of America
| | - Peng Zhang
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, New York, United States of America
| | - Huaiyu Hu
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, New York, United States of America
- * E-mail:
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37
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Noël G, Stevenson S, Moukhles H. A high throughput screen identifies chemical modulators of the laminin-induced clustering of dystroglycan and aquaporin-4 in primary astrocytes. PLoS One 2011; 6:e17559. [PMID: 21408176 PMCID: PMC3049781 DOI: 10.1371/journal.pone.0017559] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 01/26/2011] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Aquaporin-4 (AQP4) constitutes the principal water channel in the brain and is clustered at the perivascular astrocyte endfeet. This specific distribution of AQP4 plays a major role in maintaining water homeostasis in the brain. A growing body of evidence points to a role of the dystroglycan complex and its interaction with perivascular laminin in the clustering of AQP4 at perivascular astrocyte endfeet. Indeed, mice lacking components of this complex or in which laminin-dystroglycan interaction is disrupted show a delayed onset of brain edema due to a redistribution of AQP4 away from astrocyte endfeet. It is therefore important to identify inhibitory drugs of laminin-dependent AQP4 clustering which may prevent or reduce brain edema. METHODOLOGY/PRINCIPAL FINDINGS In the present study we used primary rat astrocyte cultures to screen a library of >3,500 chemicals and identified 6 drugs that inhibit the laminin-induced clustering of dystroglycan and AQP4. Detailed analysis of the inhibitory drug, chloranil, revealed that its inhibition of the clustering is due to the metalloproteinase-2-mediated ß-dystroglycan shedding and subsequent loss of laminin interaction with dystroglycan. Furthermore, chemical variants of chloranil induced a similar effect on ß-dystroglycan and this was prevented by the antioxidant N-acetylcysteine. CONCLUSION/SIGNIFICANCE These findings reveal the mechanism of action of chloranil in preventing the laminin-induced clustering of dystroglycan and AQP4 and validate the use of high-throughput screening as a tool to identify drugs that modulate AQP4 clustering and that could be tested in models of brain edema.
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Affiliation(s)
- Geoffroy Noël
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Sarah Stevenson
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
- * E-mail:
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38
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Takawira D, Budinger GRS, Hopkinson SB, Jones JCR. A dystroglycan/plectin scaffold mediates mechanical pathway bifurcation in lung epithelial cells. J Biol Chem 2010; 286:6301-10. [PMID: 21149456 DOI: 10.1074/jbc.m110.178988] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In alveolar epithelial cells (AECs), the membrane-anchored proteoglycan dystroglycan (DG) is a mechanoreceptor that transmits mechanical stretch forces to activate independently the ERK1/2 and the adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling cascades in a process called pathway bifurcation. We tested the hypothesis that the cytoskeleton cross-linker plectin, known to bind both DG and AMPK in muscle cells, acts as a scaffold to regulate DG-mediated mechanical stimulation and pathway bifurcation. We demonstrate that plectin and DG form a complex in AECs and that this complex interacts with ERK1/2 and AMPK. Plectin knockdown reduces DG interaction with AMPK but not with ERK1/2. Despite this, mechanoactivation of both signaling pathways is significantly attenuated in AECs deficient in plectin. Thus, DG has the dual role of mechanical receptor and scaffold for ERK1/2, whereas plectin acts as a scaffold for AMPK signaling but is also required for DG-mediated ERK1/2 activation. We conclude that the DG-plectin complex plays a central role in transmitting mechanical stress from the extracellular matrix to the cytoplasm.
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Affiliation(s)
- Desire Takawira
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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39
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Geranmayeh F, Clement E, Feng LH, Sewry C, Pagan J, Mein R, Abbs S, Brueton L, Childs AM, Jungbluth H, De Goede CG, Lynch B, Lin JP, Chow G, Sousa CD, O'Mahony O, Majumdar A, Straub V, Bushby K, Muntoni F. Genotype-phenotype correlation in a large population of muscular dystrophy patients with LAMA2 mutations. Neuromuscul Disord 2010; 20:241-50. [PMID: 20207543 DOI: 10.1016/j.nmd.2010.02.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 01/09/2010] [Accepted: 02/01/2010] [Indexed: 11/25/2022]
Abstract
Merosin deficient congenital muscular dystrophy 1A (MDC1A) results from mutations in the LAMA2 gene. We report 51 patients with MDC1A and examine the relationship between degree of merosin expression, genotype and clinical features. Thirty-three patients had absence of merosin and 13 showed some residual merosin. Compared to the residual merosin group, patients with absent merosin had an earlier presentation (<7days) (P=0.0073), were more likely to lack independent ambulation (P=0.0215), or require enteral feeding (P=0.0099) and ventilatory support (P=0.0354). We identified 33 novel LAMA2 mutations; these were distributed throughout the gene in patients with absent merosin, with minor clusters in exon 27, 14, 25 and 26 (55% of mutations). Patients with residual merosin often carried at least one splice site mutation and less frequently frameshift mutations. This large study identified novel LAMA2 mutations and highlights the role of immunohistochemical studies for merosin status in predicting clinical severity of MDC1A.
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Affiliation(s)
- Fatemeh Geranmayeh
- Dubowitz Neuromuscular Centre, Institute of Child Health & Great Ormond Street Hospital, 30 Guilford Street, London WC1N 1EH, United Kingdom
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Moore CJ, Winder SJ. Dystroglycan versatility in cell adhesion: a tale of multiple motifs. Cell Commun Signal 2010; 8:3. [PMID: 20163697 PMCID: PMC2834674 DOI: 10.1186/1478-811x-8-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Accepted: 02/17/2010] [Indexed: 12/02/2022] Open
Abstract
Dystroglycan is a ubiquitously expressed heterodimeric adhesion receptor. The extracellular α-subunit makes connections with a number of laminin G domain ligands including laminins, agrin and perlecan in the extracellular matrix and the transmembrane β-subunit makes connections to the actin filament network via cytoskeletal linkers including dystrophin, utrophin, ezrin and plectin, depending on context. Originally discovered as part of the dystrophin glycoprotein complex of skeletal muscle, dystroglycan is an important adhesion molecule and signalling scaffold in a multitude of cell types and tissues and is involved in several diseases. Dystroglycan has emerged as a multifunctional adhesion platform with many interacting partners associating with its short unstructured cytoplasmic domain. Two particular hotspots are the cytoplasmic juxtamembrane region and at the very carboxy terminus of dystroglycan. Regions which between them have several overlapping functions: in the juxtamembrane region; a nuclear localisation signal, ezrin/radixin/moesin protein, rapsyn and ERK MAP Kinase binding function, and at the C terminus a regulatory tyrosine governing WW, SH2 and SH3 domain interactions. We will discuss the binding partners for these motifs and how their interactions and regulation can modulate the involvement of dystroglycan in a range of different adhesion structures and functions depending on context. Thus dystroglycan presents as a multifunctional scaffold involved in adhesion and adhesion-mediated signalling with its functions under exquisite spatio-temporal regulation.
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Affiliation(s)
- Chris J Moore
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.
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Basement membrane in pancreatic islet function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 654:217-34. [PMID: 20217500 DOI: 10.1007/978-90-481-3271-3_10] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Clinical treatment of diabetic patients by islet transplantation faces various complications. At present, in vitro expansion of islets occurs at the cost of their essential features, which are insulin production and release. However, the recent discovery of blood vessel/beta-cell interactions as an important aspect of insulin transcription, secretion, and proliferation might point us to ways of how this problem could be overcome. The correct function of beta-cells depends on the presence of a basement membrane, a specialized extracellular matrix located around the blood vessel wall in mouse and human pancreatic islets. In this chapter, we summarize how the vascular basement membrane influences insulin transcription, insulin secretion, and beta-cell proliferation. In addition, a brief overview about basement membrane components and their interactions with cell surface receptors is given.
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Moon YW, Rha SY, Zhang X, Jeung HC, Yang WI, Kwon O, Jeong JH, Cheon SH, Yoo NC, Chung HC. Increments of alpha-dystroglycan expression in liver metastasis correlate with poor survival in gastric cancer. J Surg Oncol 2009; 100:459-65. [PMID: 19598149 DOI: 10.1002/jso.21347] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Dystroglycan (DG) is a recently focused adhesion molecule with possible roles in cancer development and progression. We investigated correlations between alpha-DG expression and prognosis in gastric carcinoma with liver metastasis. METHODS For 40 patients with gastric adenocarcinoma and liver-only metastasis, alpha-DG expression was determined by immunohistochemistry in paraffin-embedded surgical specimens of resected stomach tumor, resected liver metastasis, and their normal counterpart tissues. Correlations between alpha-DG expression and prognosis were retrospectively analyzed. RESULTS alpha-DG expression was higher in primary gastric cancer (P = 0.006) and lower in liver metastasis (P = 0.002) than in each normal counterpart. In primary stomach cancer, patients who had lower alpha-DG expression in tumors than in normal counterparts showed poor overall survival (OS) (P = 0.028). In contrast, in the liver, patients who had higher alpha-DG expression in tumors than in normal counterparts showed poor OS (P = 0.022). Also, higher alpha-DG expression in liver metastasis than in stomach tumors led to poor recurrence-free survival (P = 0.023) and OS (P = 0.056). CONCLUSIONS This approach may be used to further understanding of the pathogenesis of liver metastasis from gastric cancer. Further studies are warranted to reveal the mechanisms of alpha-DG dysregulation in liver metastasis.
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Affiliation(s)
- Yong Wha Moon
- Cancer Metastasis Research Center, Yonsei University College of Medicine, Seoul 120-752, South Korea
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Ungar D. Golgi linked protein glycosylation and associated diseases. Semin Cell Dev Biol 2009; 20:762-9. [PMID: 19508859 DOI: 10.1016/j.semcdb.2009.03.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 03/10/2009] [Accepted: 03/11/2009] [Indexed: 11/17/2022]
Abstract
One of the Golgi's main functions is the glycosylation of secreted proteins. A large variety of glycan chains can be synthesized in the Golgi, and it is increasingly clear that these are critical in basic cellular functions as well as the development of multicellular organisms. The structurally best-documented glycans are N-glycans, yet these are also the most enigmatic in their function. In contrast, O-glycan function is far better understood, but here the structures and biosynthetic pathways are very incomplete. The critical importance of glycans is highlighted by the broad spectrum of diseases they are associated with, such as a number of inherited diseases, but also cancers or diabetes. The molecular clues to these, however, are only just being elucidated. Although some glycan structures are known to be involved in signaling or adhesion to the extracellular matrix, for most the functions are not yet known. This review aims at summarizing current knowledge as much as to point out critical areas key for future progress.
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Affiliation(s)
- Daniel Ungar
- University of York, Department of Biology (area 9), PO Box 373, York YO10 5YW, UK.
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Adorjan I, Kalman M. Distribution of β-dystroglycan immunopositive globules in the subventricular zone of rat brain. Glia 2009; 57:657-66. [DOI: 10.1002/glia.20794] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Nishimune H, Valdez G, Jarad G, Moulson CL, Müller U, Miner JH, Sanes JR. Laminins promote postsynaptic maturation by an autocrine mechanism at the neuromuscular junction. ACTA ACUST UNITED AC 2008; 182:1201-15. [PMID: 18794334 PMCID: PMC2542479 DOI: 10.1083/jcb.200805095] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A prominent feature of synaptic maturation at the neuromuscular junction (NMJ) is the topological transformation of the acetylcholine receptor (AChR)-rich postsynaptic membrane from an ovoid plaque into a complex array of branches. We show here that laminins play an autocrine role in promoting this transformation. Laminins containing the alpha4, alpha5, and beta2 subunits are synthesized by muscle fibers and concentrated in the small portion of the basal lamina that passes through the synaptic cleft at the NMJ. Topological maturation of AChR clusters was delayed in targeted mutant mice lacking laminin alpha5 and arrested in mutants lacking both alpha4 and alpha5. Analysis of chimeric laminins in vivo and of mutant myotubes cultured aneurally demonstrated that the laminins act directly on muscle cells to promote postsynaptic maturation. Immunohistochemical studies in vivo and in vitro along with analysis of targeted mutants provide evidence that laminin-dependent aggregation of dystroglycan in the postsynaptic membrane is a key step in synaptic maturation. Another synaptically concentrated laminin receptor, Bcam, is dispensable. Together with previous studies implicating laminins as organizers of presynaptic differentiation, these results show that laminins coordinate post- with presynaptic maturation.
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Affiliation(s)
- Hiroshi Nishimune
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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McNally EM, Pytel P. Muscle diseases: the muscular dystrophies. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 2:87-109. [PMID: 18039094 DOI: 10.1146/annurev.pathol.2.010506.091936] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dystrophic muscle disease can occur at any age. Early- or childhood-onset muscular dystrophies may be associated with profound loss of muscle function, affecting ambulation, posture, and cardiac and respiratory function. Late-onset muscular dystrophies or myopathies may be mild and associated with slight weakness and an inability to increase muscle mass. The phenotype of muscular dystrophy is an endpoint that arises from a diverse set of genetic pathways. Genes associated with muscular dystrophies encode proteins of the plasma membrane and extracellular matrix, and the sarcomere and Z band, as well as nuclear membrane components. Because muscle has such distinctive structural and regenerative properties, many of the genes implicated in these disorders target pathways unique to muscle or more highly expressed in muscle. This chapter reviews the basic structural properties of muscle and genetic mechanisms that lead to myopathy and muscular dystrophies that affect all age groups.
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Affiliation(s)
- Elizabeth M McNally
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, Illinois 60637, USA.
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Peng H, Shah W, Holland P, Carbonetto S. Integrins and dystroglycan regulate astrocyte wound healing: the integrin beta1 subunit is necessary for process extension and orienting the microtubular network. Dev Neurobiol 2008; 68:559-74. [PMID: 18188865 DOI: 10.1002/dneu.20593] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Monolayers of astrocytes in culture respond to a scrape wound by orienting towards the wound and extending processes that will repair it. We show here that they also upregulate the expression of extracellular matrix (ECM) proteins, laminin, and chondroitin sulfated proteoglycan, that are deposited in astrocytic scars in vivo. We have previously shown that the major functional ECM receptors on astrocytes are dystroglycan (DG) plus integrins alpha1beta1, alpha5beta1, alpha6beta1, and alphavbeta3. Consistent with this, laminin fragments that activate alpha1beta1 integrin, alpha6beta1 integrin, and DG all contribute to attachment. During astrocyte attachment, or process extension, integrins and DG are found at the leading edge of the lammelipodium, though they change in distribution with the extent of attachment and the alpha and beta subunits of DG can be spatially uncoupled. Functionally, inhibitory antibodies to DG and integrin alpha1beta1 or the RGD peptide all inhibit process extension, showing that ligand engagement of integrins and DG contribute to process extension. Astrocytes differentiated from DG or beta1 null ES cells respond very differently to wounding. The former fail to extend process and cell polarization is disrupted partially. However, beta1 null astrocytes not only fail to extend processes perpendicular to the wound, but cell polarization is completely disrupted and cells migrate randomly into the wound. We conclude that integrins are essential for astrocyte polarity.
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Affiliation(s)
- Huashan Peng
- Centre for Research in Neuroscience, McGill University Health Centre, Montreal, Quebec, Canada H3G 1A4
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Klees RF, Salasznyk RM, Ward DF, Crone DE, Williams WA, Harris MP, Boskey A, Quaranta V, Plopper GE. Dissection of the osteogenic effects of laminin-332 utilizing specific LG domains: LG3 induces osteogenic differentiation, but not mineralization. Exp Cell Res 2008; 314:763-73. [PMID: 18206871 PMCID: PMC2268764 DOI: 10.1016/j.yexcr.2007.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Revised: 12/07/2007] [Accepted: 12/11/2007] [Indexed: 10/22/2022]
Abstract
The overall mechanisms governing the role of laminins during osteogenic differentiation of human mesenchymal stem cells (hMSC) are poorly understood. We previously reported that laminin-332 induces an osteogenic phenotype in hMSC and does so through a focal adhesion kinase (FAK) and extracellular signal-related kinase (ERK) dependent pathway. We hypothesized that this is a result of integrin-ECM binding, and that it occurs via the known alpha3 LG3 integrin binding domain of laminin-332. To test this hypothesis we cultured hMSC on several different globular domains of laminin-332. hMSC adhered best to the LG3 domain, and this adhesion maximally activated FAK and ERK within 120 min. Prolonged culturing (8 or 16 days) of hMSC on LG3 led to activation of the osteogenic transcription factor Runx2 and expression of key osteogenic markers (osterix, bone sialoprotein 2, osteocalcin, alkaline phosphatase, extracellular calcium) in hMSC. LG3 domain binding did not increase matrix mineralization, demonstrating that the LG3 domain alone is not sufficient to induce complete osteogenic differentiation in vitro. We conclude that the LG3 domain mediates attachment of hMSC to laminin-332 and that this adhesion recapitulates most, but not all, of the osteogenic differentiation associated with laminin-5 binding to hMSC.
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Affiliation(s)
- Robert F. Klees
- Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180−3596
| | - Roman M. Salasznyk
- Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180−3596
| | - Donald F. Ward
- Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180−3596
| | - Donna E. Crone
- Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180−3596
| | - William A. Williams
- Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180−3596
| | - Mark P. Harris
- Vanderbilt University Medical Center, Nashville, TN 37232
| | - Adele Boskey
- Hospital for Special Surgery, New York City, NY 10021
| | - Vito Quaranta
- Vanderbilt University Medical Center, Nashville, TN 37232
| | - George E. Plopper
- Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180−3596
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Ervasti JM, Sonnemann KJ. Biology of the striated muscle dystrophin-glycoprotein complex. INTERNATIONAL REVIEW OF CYTOLOGY 2008; 265:191-225. [PMID: 18275889 DOI: 10.1016/s0074-7696(07)65005-0] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Since its first description in 1990, the dystrophin-glycoprotein complex has emerged as a critical nexus for human muscular dystrophies arising from defects in a variety of distinct genes. Studies in mammals widely support a primary role for the dystrophin-glycoprotein complex in mechanical stabilization of the plasma membrane in striated muscle and provide hints for secondary functions in organizing molecules involved in cellular signaling. Studies in model organisms confirm the importance of the dystrophin-glycoprotein complex for muscle cell viability and have provided new leads toward a full understanding of its secondary roles in muscle biology.
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Affiliation(s)
- James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Colognato H, Galvin J, Wang Z, Relucio J, Nguyen T, Harrison D, Yurchenco PD, Ffrench-Constant C. Identification of dystroglycan as a second laminin receptor in oligodendrocytes, with a role in myelination. Development 2007; 134:1723-36. [PMID: 17395644 DOI: 10.1242/dev.02819] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Developmental abnormalities of myelination are observed in the brains of laminin-deficient humans and mice. The mechanisms by which these defects occur remain unknown. It has been proposed that, given their central role in mediating extracellular matrix (ECM) interactions, integrin receptors are likely to be involved. However, it is a non-integrin ECM receptor, dystroglycan, that provides the key linkage between the dystrophin-glycoprotein complex (DGC) and laminin in skeletal muscle basal lamina, such that disruption of this bridge results in muscular dystrophy. In addition, the loss of dystroglycan from Schwann cells causes myelin instability and disorganization of the nodes of Ranvier. To date, it is unknown whether dystroglycan plays a role during central nervous system (CNS) myelination. Here, we report that the myelinating glia of the CNS, oligodendrocytes, express and use dystroglycan receptors to regulate myelin formation. In the absence of normal dystroglycan expression, primary oligodendrocytes showed substantial deficits in their ability to differentiate and to produce normal levels of myelin-specific proteins. After blocking the function of dystroglycan receptors, oligodendrocytes failed both to produce complex myelin membrane sheets and to initiate myelinating segments when co-cultured with dorsal root ganglion neurons. By contrast, enhanced oligodendrocyte survival in response to the ECM, in conjunction with growth factors, was dependent on interactions with beta-1 integrins and did not require dystroglycan. Together, these results indicate that laminins are likely to regulate CNS myelination by interacting with both integrin receptors and dystroglycan receptors, and that oligodendrocyte dystroglycan receptors may have a specific role in regulating terminal stages of myelination, such as myelin membrane production, growth, or stability.
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Affiliation(s)
- Holly Colognato
- Department of Pharmacology, State University of New York, Stony Brook, NY 11794, USA.
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