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D’Elia S, Caputo A, Natale F, Pezzullo E, Limongelli G, Golino P, Cimmino G, Loffredo FS. The Desmoplakin Phenotype Spectrum: Is the Inflammation the "Fil Rouge" Linking Myocarditis, Arrhythmogenic Cardiomyopathy, and Uncommon Autoinflammatory Systemic Disease? Genes (Basel) 2024; 15:1234. [PMID: 39336825 PMCID: PMC11431300 DOI: 10.3390/genes15091234] [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: 08/08/2024] [Revised: 09/19/2024] [Accepted: 09/20/2024] [Indexed: 09/30/2024] Open
Abstract
Myocarditis is an inflammatory condition of cardiac tissue presenting significant variability in clinical manifestations and outcomes. Its etiology is diverse, encompassing infectious agents (primarily viruses, but also bacteria, protozoa, and helminths) and non-infectious factors (autoimmune responses, toxins, and drugs), though often the specific cause remains unidentified. Recent research has highlighted the potential role of genetic susceptibility in the development of myocarditis (and in some cases the development of inflammatory dilated cardiomyopathy, i.e., the condition in which there is chronic inflammation (>3 months) and left ventricular dysfunction\dilatation), with several studies indicating a correlation between myocarditis and genetic backgrounds. Notably, pathogenic genetic variants linked to dilated or arrhythmic cardiomyopathy are found in 8-16% of myocarditis patients. Genetic predispositions can lead to recurrent myocarditis and a higher incidence of ventricular arrhythmias and heart failure. Moreover, the presence of DSP mutations has been associated with distinct pathological patterns and clinical outcomes in arrhythmogenic cardiomyopathy (hot phases). The interplay between genetic factors and environmental triggers, such as viral infections and physical stress, is crucial in understanding the pathogenesis of myocarditis. Identifying these genetic markers can improve the diagnosis, risk stratification, and management of patients with myocarditis, potentially guiding tailored therapeutic interventions. This review aims to synthesize current knowledge on the genetic underpinnings of myocarditis, with an emphasis on desmoplakin-related arrhythmogenic cardiomyopathy, to enhance clinical understanding and inform future research directions.
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Affiliation(s)
- Saverio D’Elia
- Cardiology Unit, Azienda Ospedaliera Universitaria Luigi Vanvitelli, Piazza Miraglia 2, 80138 Napoli, Italy;
| | - Adriano Caputo
- Department of Translational Medical Sciences, Section of Cardiology, University of Campania Luigi Vanvitelli, 80131 Naples, Italy; (A.C.); (G.L.); (P.G.); (F.S.L.)
| | - Francesco Natale
- Vanvitelli Cardiology and Intensive Care Unit, Monaldi Hospital, 80131 Naples, Italy; (F.N.); (E.P.)
| | - Enrica Pezzullo
- Vanvitelli Cardiology and Intensive Care Unit, Monaldi Hospital, 80131 Naples, Italy; (F.N.); (E.P.)
| | - Giuseppe Limongelli
- Department of Translational Medical Sciences, Section of Cardiology, University of Campania Luigi Vanvitelli, 80131 Naples, Italy; (A.C.); (G.L.); (P.G.); (F.S.L.)
- Inherited and Rare Cardiovascular Diseases, Monaldi Hospital, 80131 Naples, Italy
| | - Paolo Golino
- Department of Translational Medical Sciences, Section of Cardiology, University of Campania Luigi Vanvitelli, 80131 Naples, Italy; (A.C.); (G.L.); (P.G.); (F.S.L.)
| | - Giovanni Cimmino
- Department of Translational Medical Sciences, Section of Cardiology, University of Campania Luigi Vanvitelli, 80131 Naples, Italy; (A.C.); (G.L.); (P.G.); (F.S.L.)
| | - Francesco S. Loffredo
- Department of Translational Medical Sciences, Section of Cardiology, University of Campania Luigi Vanvitelli, 80131 Naples, Italy; (A.C.); (G.L.); (P.G.); (F.S.L.)
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2
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Bharathan NK, Mattheyses AL, Kowalczyk AP. The desmosome comes into focus. J Cell Biol 2024; 223:e202404120. [PMID: 39120608 PMCID: PMC11317759 DOI: 10.1083/jcb.202404120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 07/26/2024] [Accepted: 07/29/2024] [Indexed: 08/10/2024] Open
Abstract
The desmosome is a cell-cell adhesive junction that provides integrity and mechanical resistance to tissues through its attachment to the intermediate filament cytoskeleton. Defects in desmosomes cause diseases impacting the heart, epidermis, and other epithelia. In this review, we provide a historical perspective on the discovery of the desmosome and how the evolution of cellular imaging technologies revealed insights into desmosome structure and function. We also discuss recent findings using contemporary imaging approaches that have informed the molecular order, three-dimensional architecture, and associations of desmosomes with organelles such as the endoplasmic reticulum. Finally, we provide an updated model of desmosome molecular organization and speculate upon novel functions of this cell junction as a signaling center for sensing mechanical and other forms of cell stress.
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Affiliation(s)
- Navaneetha Krishnan Bharathan
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Andrew P Kowalczyk
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA, USA
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3
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Risato G, Brañas Casas R, Cason M, Bueno Marinas M, Pinci S, De Gaspari M, Visentin S, Rizzo S, Thiene G, Basso C, Pilichou K, Tiso N, Celeghin R. In Vivo Approaches to Understand Arrhythmogenic Cardiomyopathy: Perspectives on Animal Models. Cells 2024; 13:1264. [PMID: 39120296 PMCID: PMC11311808 DOI: 10.3390/cells13151264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/23/2024] [Accepted: 07/24/2024] [Indexed: 08/10/2024] Open
Abstract
Arrhythmogenic cardiomyopathy (AC) is a hereditary cardiac disorder characterized by the gradual replacement of cardiomyocytes with fibrous and adipose tissue, leading to ventricular wall thinning, chamber dilation, arrhythmias, and sudden cardiac death. Despite advances in treatment, disease management remains challenging. Animal models, particularly mice and zebrafish, have become invaluable tools for understanding AC's pathophysiology and testing potential therapies. Mice models, although useful for scientific research, cannot fully replicate the complexity of the human AC. However, they have provided valuable insights into gene involvement, signalling pathways, and disease progression. Zebrafish offer a promising alternative to mammalian models, despite the phylogenetic distance, due to their economic and genetic advantages. By combining animal models with in vitro studies, researchers can comprehensively understand AC, paving the way for more effective treatments and interventions for patients and improving their quality of life and prognosis.
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Affiliation(s)
- Giovanni Risato
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
- Department of Biology, University of Padua, I-35131 Padua, Italy;
- Department of Women’s and Children’s Health, University of Padua, I-35128 Padua, Italy;
| | | | - Marco Cason
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Maria Bueno Marinas
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Serena Pinci
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Monica De Gaspari
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Silvia Visentin
- Department of Women’s and Children’s Health, University of Padua, I-35128 Padua, Italy;
| | - Stefania Rizzo
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Gaetano Thiene
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Cristina Basso
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Kalliopi Pilichou
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Natascia Tiso
- Department of Biology, University of Padua, I-35131 Padua, Italy;
| | - Rudy Celeghin
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
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Pasani S, Menon KS, Viswanath S. The molecular architecture of the desmosomal outer dense plaque by integrative structural modeling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.13.544884. [PMID: 37398295 PMCID: PMC10312763 DOI: 10.1101/2023.06.13.544884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Desmosomes mediate cell-cell adhesion and are prevalent in tissues under mechanical stress. However, their detailed structural characterization is not available. Here, we characterized the molecular architecture of the desmosomal outer dense plaque (ODP) using Bayesian integrative structural modeling via the Integrative Modeling Platform. Starting principally from the structural interpretation of an electron cryo-tomogram, we integrated information from X-ray crystallography, an immuno-electron microscopy study, biochemical assays, in-silico predictions of transmembrane and disordered regions, homology modeling, and stereochemistry information. The integrative structure was validated by information from imaging, tomography, and biochemical studies that were not used in modeling. The ODP resembles a densely packed cylinder with a PKP layer and a PG layer; the desmosomal cadherins and PKP span these two layers. Our integrative approach allowed us to localize disordered regions, such as N-PKP and PG-C. We refined previous protein-protein interactions between desmosomal proteins and provided possible structural hypotheses for defective cell-cell adhesion in several diseases by mapping disease-related mutations on the structure. Finally, we point to features of the structure that could confer resilience to mechanical stress. Our model provides a basis for generating experimentally verifiable hypotheses on the structure and function of desmosomal proteins in normal and disease states.
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Affiliation(s)
- Satwik Pasani
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Kavya S Menon
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Shruthi Viswanath
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
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5
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Fülle JB, de Almeida RA, Lawless C, Stockdale L, Yanes B, Lane EB, Garrod DR, Ballestrem C. Proximity Mapping of Desmosomes Reveals a Striking Shift in Their Molecular Neighborhood Associated With Maturation. Mol Cell Proteomics 2024; 23:100735. [PMID: 38342409 PMCID: PMC10943070 DOI: 10.1016/j.mcpro.2024.100735] [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: 05/04/2023] [Revised: 01/29/2024] [Accepted: 02/08/2024] [Indexed: 02/13/2024] Open
Abstract
Desmosomes are multiprotein adhesion complexes that link intermediate filaments to the plasma membrane, ensuring the mechanical integrity of cells across tissues, but how they participate in the wider signaling network to exert their full function is unclear. To investigate this, we carried out protein proximity mapping using biotinylation (BioID). The combined interactomes of the essential desmosomal proteins desmocollin 2a, plakoglobin, and plakophilin 2a (Pkp2a) in Madin-Darby canine kidney epithelial cells were mapped and their differences and commonalities characterized as desmosome matured from Ca2+ dependence to the mature, Ca2+-independent, hyper-adhesive state, which predominates in tissues. Results suggest that individual desmosomal proteins have distinct roles in connecting to cellular signaling pathways and that these roles alter substantially when cells change their adhesion state. The data provide further support for a dualistic concept of desmosomes in which the properties of Pkp2a differ from those of the other, more stable proteins. This body of data provides an invaluable resource for the analysis of desmosome function.
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Affiliation(s)
- Judith B Fülle
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK
| | | | - Craig Lawless
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK
| | - Liam Stockdale
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK
| | - Bian Yanes
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK
| | - E Birgitte Lane
- Skin Research Institute of Singapore, Agency of Science Technology and Research (A∗STAR), Singapore, Singapore
| | - David R Garrod
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK.
| | - Christoph Ballestrem
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, UK.
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van Opbergen CJ, Narayanan B, Sacramento CB, Stiles KM, Mishra V, Frenk E, Ricks D, Chen G, Zhang M, Yarabe P, Schwartz J, Delmar M, Herzog CD, Cerrone M. AAV-Mediated Delivery of Plakophilin-2a Arrests Progression of Arrhythmogenic Right Ventricular Cardiomyopathy in Murine Hearts: Preclinical Evidence Supporting Gene Therapy in Humans. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2024; 17:e004305. [PMID: 38288614 PMCID: PMC10923105 DOI: 10.1161/circgen.123.004305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 11/30/2023] [Indexed: 02/22/2024]
Abstract
BACKGROUND Pathogenic variants in PKP2 (plakophilin-2) cause arrhythmogenic right ventricular cardiomyopathy, a disease characterized by life-threatening arrhythmias and progressive cardiomyopathy leading to heart failure. No effective medical therapy is available to prevent or arrest the disease. We tested the hypothesis that adeno-associated virus vector-mediated delivery of the human PKP2 gene to an adult mammalian heart deficient in PKP2 can arrest disease progression and significantly prolong survival. METHODS Experiments were performed using a PKP2-cKO (cardiac-specific, tamoxifen-activated PKP2 knockout murine model). The potential therapeutic, adeno-associated virus vector of serotype rh.74 (AAVrh.74)-PKP2a (PKP2 variant A; RP-A601) is a recombinant AAVrh.74 gene therapy viral vector encoding the human PKP2 variant A. AAVrh.74-PKP2a was delivered to adult mice by a single tail vein injection either before or after tamoxifen-activated PKP2-cKO. PKP2 expression was confirmed by molecular and histopathologic analyses. Cardiac function and disease progression were monitored by survival analyses, echocardiography, and electrocardiography. RESULTS Consistent with prior findings, loss of PKP2 expression caused 100% mortality within 50 days after tamoxifen injection. In contrast, AAVrh.74-PKP2a-mediated PKP2a expression resulted in 100% survival for >5 months (at study termination). Echocardiographic analysis revealed that AAVrh.74-PKP2a prevented right ventricle dilation, arrested left ventricle functional decline, and mitigated arrhythmia burden. Molecular and histological analyses showed AAVrh.74-PKP2a-mediated transgene mRNA and protein expression and appropriate PKP2 localization at the cardiomyocyte intercalated disc. Importantly, the therapeutic benefit was shown in mice receiving AAVrh.74-PKP2a after disease onset. CONCLUSIONS These preclinical data demonstrate the potential for AAVrh.74-PKP2a (RP-A601) as a therapeutic for PKP2-related arrhythmogenic right ventricular cardiomyopathy in both early and more advanced stages of the disease.
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Affiliation(s)
| | | | | | | | | | | | | | - Grace Chen
- The Leon Charney Division of Cardiology, New York Univ Grossmann School of Medicine, New York, NY
| | - Mingliang Zhang
- The Leon Charney Division of Cardiology, New York Univ Grossmann School of Medicine, New York, NY
| | | | | | - Mario Delmar
- The Leon Charney Division of Cardiology, New York Univ Grossmann School of Medicine, New York, NY
| | | | - Marina Cerrone
- The Leon Charney Division of Cardiology, New York Univ Grossmann School of Medicine, New York, NY
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7
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Celeghin R, Risato G, Beffagna G, Cason M, Bueno Marinas M, Della Barbera M, Facchinello N, Giuliodori A, Brañas Casas R, Caichiolo M, Vettori A, Grisan E, Rizzo S, Dalla Valle L, Argenton F, Thiene G, Tiso N, Pilichou K, Basso C. A novel DSP zebrafish model reveals training- and drug-induced modulation of arrhythmogenic cardiomyopathy phenotypes. Cell Death Discov 2023; 9:441. [PMID: 38057295 DOI: 10.1038/s41420-023-01741-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 10/30/2023] [Accepted: 11/23/2023] [Indexed: 12/08/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (AC) is an inherited disorder characterized by progressive loss of the ventricular myocardium causing life-threatening ventricular arrhythmias, syncope and sudden cardiac death in young and athletes. About 40% of AC cases carry one or more mutations in genes encoding for desmosomal proteins, including Desmoplakin (Dsp). We present here the first stable Dsp knock-out (KO) zebrafish line able to model cardiac alterations and cell signalling dysregulation, characteristic of the AC disease, on which environmental factors and candidate drugs can be tested. Our stable Dsp knock-out (KO) zebrafish line was characterized by cardiac alterations, oedema and bradycardia at larval stages. Histological analysis of mutated adult hearts showed reduced contractile structures and abnormal shape of the ventricle, with thinning of the myocardial layer, vessels dilation and presence of adipocytes within the myocardium. Moreover, TEM analysis revealed "pale", disorganized and delocalized desmosomes. Intensive physical training protocol caused a global worsening of the cardiac phenotype, accelerating the progression of the disease. Of note, we detected a decrease of Wnt/β-catenin signalling, recently associated with AC pathogenesis, as well as Hippo/YAP-TAZ and TGF-β pathway dysregulation. Pharmacological treatment of mutated larvae with SB216763, a Wnt/β-catenin agonist, rescued pathway expression and cardiac abnormalities, stabilizing the heart rhythm. Overall, our Dsp KO zebrafish line recapitulates many AC features observed in human patients, pointing at zebrafish as a suitable system for in vivo analysis of environmental modulators, such as the physical exercise, and the screening of pathway-targeted drugs, especially related to the Wnt/β-catenin signalling cascade.
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Affiliation(s)
- Rudy Celeghin
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Giovanni Risato
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
- Department of Biology, University of Padova, Padova, 35131, Italy
| | - Giorgia Beffagna
- Department of Biology, University of Padova, Padova, 35131, Italy.
| | - Marco Cason
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Maria Bueno Marinas
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Mila Della Barbera
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Nicola Facchinello
- Neuroscience Institute, Italian National Research Council (CNR), Padova, 35131, Italy
| | - Alice Giuliodori
- Department of Biology, University of Padova, Padova, 35131, Italy
| | | | - Micol Caichiolo
- Department of Biology, University of Padova, Padova, 35131, Italy
| | - Andrea Vettori
- Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | - Enrico Grisan
- School of Engineering, London South Bank University, London, SE1 0AA, UK
| | - Stefania Rizzo
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | | | | | - Gaetano Thiene
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Natascia Tiso
- Department of Biology, University of Padova, Padova, 35131, Italy.
| | - Kalliopi Pilichou
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Cristina Basso
- Department of Cardiac-Thoracic-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy.
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Nielsen MS, van Opbergen CJM, van Veen TAB, Delmar M. The intercalated disc: a unique organelle for electromechanical synchrony in cardiomyocytes. Physiol Rev 2023; 103:2271-2319. [PMID: 36731030 PMCID: PMC10191137 DOI: 10.1152/physrev.00021.2022] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
The intercalated disc (ID) is a highly specialized structure that connects cardiomyocytes via mechanical and electrical junctions. Although described in some detail by light microscopy in the 19th century, it was in 1966 that electron microscopy images showed that the ID represented apposing cell borders and provided detailed insight into the complex ID nanostructure. Since then, much has been learned about the ID and its molecular composition, and it has become evident that a large number of proteins, not all of them involved in direct cell-to-cell coupling via mechanical or gap junctions, reside at the ID. Furthermore, an increasing number of functional interactions between ID components are emerging, leading to the concept that the ID is not the sum of isolated molecular silos but an interacting molecular complex, an "organelle" where components work in concert to bring about electrical and mechanical synchrony. The aim of the present review is to give a short historical account of the ID's discovery and an updated overview of its composition and organization, followed by a discussion of the physiological implications of the ID architecture and the local intermolecular interactions. The latter will focus on both the importance of normal conduction of cardiac action potentials as well as the impact on the pathophysiology of arrhythmias.
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Affiliation(s)
- Morten S Nielsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Chantal J M van Opbergen
- The Leon Charney Division of Cardiology, New York University Grossmann School of Medicine, New York, New York, United States
| | - Toon A B van Veen
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mario Delmar
- The Leon Charney Division of Cardiology, New York University Grossmann School of Medicine, New York, New York, United States
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9
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Bharathan NK, Giang W, Hoffman CL, Aaron JS, Khuon S, Chew TL, Preibisch S, Trautman ET, Heinrich L, Bogovic J, Bennett D, Ackerman D, Park W, Petruncio A, Weigel AV, Saalfeld S, Wayne Vogl A, Stahley SN, Kowalczyk AP. Architecture and dynamics of a desmosome-endoplasmic reticulum complex. Nat Cell Biol 2023; 25:823-835. [PMID: 37291267 PMCID: PMC10960982 DOI: 10.1038/s41556-023-01154-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 04/24/2023] [Indexed: 06/10/2023]
Abstract
The endoplasmic reticulum (ER) forms a dynamic network that contacts other cellular membranes to regulate stress responses, calcium signalling and lipid transfer. Here, using high-resolution volume electron microscopy, we find that the ER forms a previously unknown association with keratin intermediate filaments and desmosomal cell-cell junctions. Peripheral ER assembles into mirror image-like arrangements at desmosomes and exhibits nanometre proximity to keratin filaments and the desmosome cytoplasmic plaque. ER tubules exhibit stable associations with desmosomes, and perturbation of desmosomes or keratin filaments alters ER organization, mobility and expression of ER stress transcripts. These findings indicate that desmosomes and the keratin cytoskeleton regulate the distribution, function and dynamics of the ER network. Overall, this study reveals a previously unknown subcellular architecture defined by the structural integration of ER tubules with an epithelial intercellular junction.
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Affiliation(s)
- Navaneetha Krishnan Bharathan
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - William Giang
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Coryn L Hoffman
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Jesse S Aaron
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Satya Khuon
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Teng-Leong Chew
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Stephan Preibisch
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Eric T Trautman
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Larissa Heinrich
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - John Bogovic
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Davis Bennett
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - David Ackerman
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Woohyun Park
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Alyson Petruncio
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Aubrey V Weigel
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Stephan Saalfeld
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - A Wayne Vogl
- Life Sciences Institute and the Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sara N Stahley
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Andrew P Kowalczyk
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
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10
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The Adhesion G-Protein-Coupled Receptor GPR115/ADGRF4 Regulates Epidermal Differentiation and Associates with Cytoskeletal KRT1. Cells 2022; 11:cells11193151. [PMID: 36231117 PMCID: PMC9563031 DOI: 10.3390/cells11193151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/23/2022] [Accepted: 10/03/2022] [Indexed: 11/27/2022] Open
Abstract
Among the 33 human adhesion G-protein-coupled receptors (aGPCRs), a unique subfamily of GPCRs, only ADGRF4, encoding GPR115, shows an obvious skin-dominated transcriptomic profile, but its expression and function in skin is largely unknown. Here, we report that GPR115 is present in a small subset of basal and in most suprabasal, noncornified keratinocytes of the stratified epidermis, supporting epidermal transcriptomic data. In psoriatic skin, characterized by hyperproliferation and delayed differentiation, the expression of GPR115 and KRT1/10, the fundamental suprabasal keratin dimer, is delayed. The deletion of ADGRF4 in HaCaT keratinocytes grown in an organotypic mode abrogates KRT1 and reduces keratinocyte stratification, indicating a role of GPR115 in epidermal differentiation. Unexpectedly, endogenous GPR115, which is not glycosylated and is likely not proteolytically processed, localizes intracellularly along KRT1/10-positive keratin filaments in a regular pattern. Our data demonstrate a hitherto unknown function of GPR115 in the regulation of epidermal differentiation and KRT1.
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11
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Schmitt T, Pircher J, Steinert L, Meier K, Ghoreschi K, Vielmuth F, Kugelmann D, Waschke J. Dsg1 and Dsg3 Composition of Desmosomes Across Human Epidermis and Alterations in Pemphigus Vulgaris Patient Skin. Front Immunol 2022; 13:884241. [PMID: 35711465 PMCID: PMC9196036 DOI: 10.3389/fimmu.2022.884241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
Desmosomes are important epidermal adhesion units and signalling hubs, which play an important role in pemphigus pathogenesis. Different expression patterns of the pemphigus autoantigens desmoglein (Dsg)1 and Dsg3 across different epidermal layers have been demonstrated. However, little is known about changes in desmosome composition in different epidermal layers or in patient skin. The aim of this study was thus to characterize desmosome composition in healthy and pemphigus skin using super-resolution microscopy. An increasing Dsg1/Dsg3 ratio from lower basal (BL) to uppermost granular layer (GL) was observed. Within BL desmosomes, Dsg1 and Dsg3 were more homogeneously distributed whereas superficial desmosomes mostly comprised one of the two molecules or domains containing either one but not both. Extradesmosomal, desmoplakin (Dp)-independent, co-localization of Dsg3 with plakoglobin (Pg) was found mostly in BL and extradesmosomal Dsg1 co-localization with Pg in all layers. In contrast, in the spinous layer (SL) most Dsg1 and Dsg3 staining was confined to desmosomes, as revealed by the co-localization with Dp. In pemphigus patient skin, Dsg1 and Dsg3 immunostaining was altered especially along blister edges. The number of desmosomes in patient skin was reduced significantly in basal and spinous layer keratinocytes with only few split desmosomes found. In addition, Dsg1-Pg co-localization at the apical BL and Dsg3-Pg co-localization in SL were significantly reduced in patients, suggesting that that extradesmosomal Dsg molecules were affected. These results support the hypothesis that pemphigus is a desmosome assembly disease and may help to explain histopathologic differences between pemphigus phenotypes.
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Affiliation(s)
- Thomas Schmitt
- Chair of Vegetative Anatomy, Instiute of Anatomy, Faculty of Medicine, Ludwig-Maximilian-Universität München (LMU) Munich, München, Germany
| | - Julia Pircher
- Chair of Vegetative Anatomy, Instiute of Anatomy, Faculty of Medicine, Ludwig-Maximilian-Universität München (LMU) Munich, München, Germany
| | - Letyfee Steinert
- Chair of Vegetative Anatomy, Instiute of Anatomy, Faculty of Medicine, Ludwig-Maximilian-Universität München (LMU) Munich, München, Germany
| | - Katharina Meier
- Department of Dermatology, Venereology and Allergology, Charité-Universitätsmedizin Berli, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Kamran Ghoreschi
- Department of Dermatology, Venereology and Allergology, Charité-Universitätsmedizin Berli, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Franziska Vielmuth
- Chair of Vegetative Anatomy, Instiute of Anatomy, Faculty of Medicine, Ludwig-Maximilian-Universität München (LMU) Munich, München, Germany
| | - Daniela Kugelmann
- Chair of Vegetative Anatomy, Instiute of Anatomy, Faculty of Medicine, Ludwig-Maximilian-Universität München (LMU) Munich, München, Germany
| | - Jens Waschke
- Chair of Vegetative Anatomy, Instiute of Anatomy, Faculty of Medicine, Ludwig-Maximilian-Universität München (LMU) Munich, München, Germany
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12
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Egu DT, Schmitt T, Waschke J. Mechanisms Causing Acantholysis in Pemphigus-Lessons from Human Skin. Front Immunol 2022; 13:884067. [PMID: 35720332 PMCID: PMC9205406 DOI: 10.3389/fimmu.2022.884067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
Pemphigus vulgaris (PV) is an autoimmune bullous skin disease caused primarily by autoantibodies (PV-IgG) against the desmosomal adhesion proteins desmoglein (Dsg)1 and Dsg3. PV patient lesions are characterized by flaccid blisters and ultrastructurally by defined hallmarks including a reduction in desmosome number and size, formation of split desmosomes, as well as uncoupling of keratin filaments from desmosomes. The pathophysiology underlying the disease is known to involve several intracellular signaling pathways downstream of PV-IgG binding. Here, we summarize our studies in which we used transmission electron microscopy to characterize the roles of signaling pathways in the pathogenic effects of PV-IgG on desmosome ultrastructure in a human ex vivo skin model. Blister scores revealed inhibition of p38MAPK, ERK and PLC/Ca2+ to be protective in human epidermis. In contrast, inhibition of Src and PKC, which were shown to be protective in cell cultures and murine models, was not effective for human skin explants. The ultrastructural analysis revealed that for preventing skin blistering at least desmosome number (as modulated by ERK) or keratin filament insertion (as modulated by PLC/Ca2+) need to be ameliorated. Other pathways such as p38MAPK regulate desmosome number, size, and keratin insertion indicating that they control desmosome assembly and disassembly on different levels. Taken together, studies in human skin delineate target mechanisms for the treatment of pemphigus patients. In addition, ultrastructural analysis supports defining the specific role of a given signaling molecule in desmosome turnover at ultrastructural level.
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13
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Yeruva S, Waschke J. Structure and regulation of desmosomes in intercalated discs: Lessons from epithelia. J Anat 2022; 242:81-90. [PMID: 35128661 PMCID: PMC9773171 DOI: 10.1111/joa.13634] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/22/2021] [Accepted: 01/10/2022] [Indexed: 12/25/2022] Open
Abstract
For electromechanical coupling of cardiomyocytes, intercalated discs (ICDs) are pivotal as highly specialized intercellular contact areas. ICD consists of adhesive contacts, such as desmosomes and adherens junctions (AJs) that are partially intermingled and thereby form an area composita to provide mechanical strength, as well as gap junctions (GJ) and sodium channels for excitation propagation. In contrast, in epithelia, mixed junctions with features of desmosomes and AJs are regarded as transitory primarily during the formation of desmosomes. The anatomy of desmosomes is defined by a typical ultrastructure with dense intracellular plaques anchoring the cadherin-type adhesion molecules to the intermediate filament cytoskeleton. Desmosomal diseases characterized by impaired adhesive and signalling functions of desmosomal contacts lead to arrhythmogenic cardiomyopathy when affecting cardiomyocytes and cause pemphigus when manifesting in keratinocytes or present as cardiocutaneous syndromes when both cell types are targeted by the disease, which underscores the high biomedical relevance of these cell contacts. Therefore, comparative analyses regarding the structure and regulation of desmosomal contacts in cardiomyocytes and epithelial cells are helpful to better understand disease pathogenesis. In this brief review, we describe the structural properties of ICD compared to epithelial desmosomes and suggest that mechanisms regulating adhesion may at least in part be comparable. Also, we discuss whether phenomena such as hyperadhesion or the bidirectional regulation of desmosomes to serve as signalling hubs in epithelial cells may also be relevant for ICD.
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Affiliation(s)
- Sunil Yeruva
- Ludwig‐Maximilian‐Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I – Vegetative AnatomieMunichGermany
| | - Jens Waschke
- Ludwig‐Maximilian‐Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I – Vegetative AnatomieMunichGermany
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14
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Beggs RR, Rao TC, Dean WF, Kowalczyk AP, Mattheyses AL. Desmosomes undergo dynamic architectural changes during assembly and maturation. Tissue Barriers 2022; 10:2017225. [PMID: 34983311 PMCID: PMC9621066 DOI: 10.1080/21688370.2021.2017225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Desmosomes are macromolecular cell-cell junctions critical for maintaining adhesion and resisting mechanical stress in epithelial tissue. Desmosome assembly and the relationship between maturity and molecular architecture are not well understood. To address this, we employed a calcium switch assay to synchronize assembly followed by quantification of desmosome nanoscale organization using direct Stochastic Optical Reconstruction Microscopy (dSTORM). We found that the organization of the desmoplakin rod/C-terminal junction changed over the course of maturation, as indicated by a decrease in the plaque-to-plaque distance, while the plaque length increased. In contrast, the desmoplakin N-terminal domain and plakoglobin organization (plaque-to-plaque distance) were constant throughout maturation. This structural rearrangement of desmoplakin was concurrent with desmosome maturation measured by E-cadherin exclusion and increased adhesive strength. Using two-color dSTORM, we showed that while the number of individual E-cadherin containing junctions went down with the increasing time in high Ca2+, they maintained a wider desmoplakin rod/C-terminal plaque-to-plaque distance. This indicates that the maturation state of individual desmosomes can be identified by their architectural organization. We confirmed these architectural changes in another model of desmosome assembly, cell migration. Desmosomes in migrating cells, closest to the scratch where they are assembling, were shorter, E-cadherin enriched, and had wider desmoplakin rod/C-terminal plaque-to-plaque distances compared to desmosomes away from the wound edge. Key results were demonstrated in three cell lines representing simple, transitional, and stratified epithelia. Together, these data suggest that there is a set of architectural programs for desmosome maturation, and we hypothesize that desmoplakin architecture may be a contributing mechanism to regulating adhesive strength.
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Affiliation(s)
- Reena R Beggs
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tejeshwar C Rao
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - William F Dean
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Andrew P Kowalczyk
- Departments of Dermatology and Cellular and Molecular Physiology, Pennsylvania State College of Medicine, Hershey, PA, USA
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
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15
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Fülle JB, Huppert H, Liebl D, Liu J, Alves de Almeida R, Yanes B, Wright GD, Lane EB, Garrod DR, Ballestrem C. Desmosome dualism - most of the junction is stable, but a plakophilin moiety is persistently dynamic. J Cell Sci 2021; 134:272445. [PMID: 34635908 DOI: 10.1242/jcs.258906] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 10/05/2021] [Indexed: 01/06/2023] Open
Abstract
Desmosomes, strong cell-cell junctions of epithelia and cardiac muscle, link intermediate filaments to cell membranes and mechanically integrate cells across tissues, dissipating mechanical stress. They comprise five major protein classes - desmocollins and desmogleins (the desmosomal cadherins), plakoglobin, plakophilins and desmoplakin - whose individual contribution to the structure and turnover of desmosomes is poorly understood. Using live-cell imaging together with fluorescence recovery after photobleaching (FRAP) and fluorescence loss and localisation after photobleaching (FLAP), we show that desmosomes consist of two contrasting protein moieties or modules: a very stable moiety of desmosomal cadherins, desmoplakin and plakoglobin, and a highly mobile plakophilin (Pkp2a). As desmosomes mature from Ca2+ dependence to Ca2+-independent hyper-adhesion, their stability increases, but Pkp2a remains highly mobile. We show that desmosome downregulation during growth-factor-induced cell scattering proceeds by internalisation of whole desmosomes, which still retain a stable moiety and highly mobile Pkp2a. This molecular mobility of Pkp2a suggests a transient and probably regulatory role for Pkp2a in desmosomes. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Judith B Fülle
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK.,Skin Research Institute of Singapore, Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648 Singapore, Singapore
| | - Henri Huppert
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK.,Institute of Medical Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673 Singapore, Singapore
| | - David Liebl
- A*STAR Microscopy Platform, Research Support Centre, Agency of Science Technology and Research (A*STAR), Biopolis 138673 Singapore, Singapore
| | - Jaron Liu
- Institute of Medical Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673 Singapore, Singapore
| | - Rogerio Alves de Almeida
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
| | - Bian Yanes
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
| | - Graham D Wright
- Skin Research Institute of Singapore, Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648 Singapore, Singapore.,A*STAR Microscopy Platform, Research Support Centre, Agency of Science Technology and Research (A*STAR), Biopolis 138673 Singapore, Singapore
| | - E Birgitte Lane
- Skin Research Institute of Singapore, Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648 Singapore, Singapore
| | - David R Garrod
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
| | - Christoph Ballestrem
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
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16
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Poller W, Haas J, Klingel K, Kühnisch J, Gast M, Kaya Z, Escher F, Kayvanpour E, Degener F, Opgen-Rhein B, Berger F, Mochmann HC, Skurk C, Heidecker B, Schultheiss HP, Monserrat L, Meder B, Landmesser U, Klaassen S. Familial Recurrent Myocarditis Triggered by Exercise in Patients With a Truncating Variant of the Desmoplakin Gene. J Am Heart Assoc 2020; 9:e015289. [PMID: 32410525 PMCID: PMC7660888 DOI: 10.1161/jaha.119.015289] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Variants of the desmosomal protein desmoplakin are associated with arrhythmogenic cardiomyopathy, an important cause of ventricular arrhythmias in children and young adults. Disease penetrance of desmoplakin variants is incomplete and variant carriers may display noncardiac, dermatologic phenotypes. We describe a novel cardiac phenotype associated with a truncating desmoplakin variant, likely causing mechanical instability of myocardial desmosomes. Methods and Results In 2 young brothers with recurrent myocarditis triggered by physical exercise, screening of 218 cardiomyopathy‐related genes identified the heterozygous truncating variant p.Arg1458Ter in desmoplakin. Screening for infections yielded no evidence of viral or nonviral infections. Myosin and troponin I autoantibodies were detected at high titers. Immunohistology failed to detect any residual DSP protein in endomyocardial biopsies, and none of the histologic criteria of arrhythmogenic cardiomyopathy were fulfilled. Cardiac magnetic resonance imaging revealed no features associated with right ventricular arrhythmogenic cardiomyopathy, but multifocal subepicardial late gadolinium enhancement was present in the left ventricles of both brothers. Screening of adult cardiomyopathy cohorts for truncating variants identified the rare genetic variants p.Gln307Ter, p.Tyr1391Ter, and p.Tyr1512Ter, suggesting that over subsequent decades critical genetic/exogenous modifiers drive pathogenesis from desmoplakin truncations toward different end points. Conclusions The described novel phenotype of familial recurrent myocarditis associated with a desmoplakin truncation in adolescents likely represents a serendipitously revealed subtype of arrhythmogenic cardiomyopathy. It may be caused by a distinctive adverse effect of the variant desmoplakin upon the mechanical stability of myocardial desmosomes. Variant screening is advisable to allow early detection of patients with similar phenotypes.
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Affiliation(s)
- Wolfgang Poller
- Department of Cardiology Campus Benjamin Franklin Universitätsmedizin Berlin Germany.,Berlin-Brandenburg Center for Regenerative Therapies (BCRT) Universitätsmedizin Berlin Germany.,German Center for Cardiovascular Research (DZHK) partner site Berlin Germany
| | - Jan Haas
- German Center for Cardiovascular Research (DZHK) partner site Heidelberg Germany.,Department of Cardiology University Hospital Heidelberg Mannheim Germany
| | - Karin Klingel
- Institute for Pathology and Neuropathology Department of Pathology University Hospital Tübingen Germany
| | - Jirko Kühnisch
- German Center for Cardiovascular Research (DZHK) partner site Berlin Germany.,Experimental and Clinical Research Center (ECRC) Universitätsmedizin Berlin Germany
| | - Martina Gast
- Department of Cardiology Campus Benjamin Franklin Universitätsmedizin Berlin Germany
| | - Ziya Kaya
- German Center for Cardiovascular Research (DZHK) partner site Heidelberg Germany.,Department of Cardiology University Hospital Heidelberg Mannheim Germany
| | - Felicitas Escher
- Department of Cardiology Campus Virchow Klinikum Universitätsmedizin Berlin Germany.,Institute for Clinical Diagnostics and Therapy (IKDT) Berlin Germany
| | - Elham Kayvanpour
- German Center for Cardiovascular Research (DZHK) partner site Heidelberg Germany.,Department of Cardiology University Hospital Heidelberg Mannheim Germany
| | - Franziska Degener
- German Center for Cardiovascular Research (DZHK) partner site Berlin Germany.,German Heart Center (DHZB) Berlin Germany
| | - Bernd Opgen-Rhein
- Department of Pediatric Cardiology Universitätsmedizin Berlin Germany
| | - Felix Berger
- German Center for Cardiovascular Research (DZHK) partner site Berlin Germany.,German Heart Center (DHZB) Berlin Germany.,Department of Pediatric Cardiology Universitätsmedizin Berlin Germany
| | | | - Carsten Skurk
- Department of Cardiology Campus Benjamin Franklin Universitätsmedizin Berlin Germany
| | - Bettina Heidecker
- Department of Cardiology Campus Benjamin Franklin Universitätsmedizin Berlin Germany
| | | | | | - Benjamin Meder
- German Center for Cardiovascular Research (DZHK) partner site Heidelberg Germany.,Department of Cardiology University Hospital Heidelberg Mannheim Germany.,Department of Genetics Stanford University School of Medicine Palo Alto CA
| | - Ulf Landmesser
- Department of Cardiology Campus Benjamin Franklin Universitätsmedizin Berlin Germany.,German Center for Cardiovascular Research (DZHK) partner site Berlin Germany.,Berlin Institute of Health Berlin Germany
| | - Sabine Klaassen
- German Center for Cardiovascular Research (DZHK) partner site Berlin Germany.,Experimental and Clinical Research Center (ECRC) Universitätsmedizin Berlin Germany.,Department of Pediatric Cardiology Universitätsmedizin Berlin Germany
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17
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Mechanical loading of desmosomes depends on the magnitude and orientation of external stress. Nat Commun 2018; 9:5284. [PMID: 30538252 PMCID: PMC6290003 DOI: 10.1038/s41467-018-07523-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 11/08/2018] [Indexed: 01/19/2023] Open
Abstract
Desmosomes are intercellular adhesion complexes that connect the intermediate filament cytoskeletons of neighboring cells, and are essential for the mechanical integrity of mammalian tissues. Mutations in desmosomal proteins cause severe human pathologies including epithelial blistering and heart muscle dysfunction. However, direct evidence for their load-bearing nature is lacking. Here we develop Förster resonance energy transfer (FRET)-based tension sensors to measure the forces experienced by desmoplakin, an obligate desmosomal protein that links the desmosomal plaque to intermediate filaments. Our experiments reveal that desmoplakin does not experience significant tension under most conditions, but instead becomes mechanically loaded when cells are exposed to external mechanical stresses. Stress-induced loading of desmoplakin is transient and sensitive to the magnitude and orientation of the applied tissue deformation, consistent with a stress absorbing function for desmosomes that is distinct from previously analyzed cell adhesion complexes. Desmosomes are intercellular adhesion complexes that connect the intermediate filament cytoskeletons of neighboring cells but direct evidence for their load-bearing nature is lacking. Here the authors develop FRET-based tension sensors to measure the forces experienced by desmoplakin and infer that desmosomes become mechanically loaded when cells are exposed to external mechanical stresses.
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18
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Sinha AA, Sajda T. The Evolving Story of Autoantibodies in Pemphigus Vulgaris: Development of the "Super Compensation Hypothesis". Front Med (Lausanne) 2018; 5:218. [PMID: 30155465 PMCID: PMC6102394 DOI: 10.3389/fmed.2018.00218] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 07/16/2018] [Indexed: 12/11/2022] Open
Abstract
Emerging data and innovative technologies are re-shaping our understanding of the scope and specificity of the autoimmune response in Pemphigus vulgaris (PV), a prototypical humorally mediated autoimmune skin blistering disorder. Seminal studies identified the desmosomal proteins Desmoglein 3 and 1 (Dsg3 and Dsg1), cadherin family proteins which function to maintain cell adhesion, as the primary targets of pathogenic autoAbs. Consequently, pathogenesis in PV has primarily considered to be the result of anti-Dsg autoAbs alone. However, accumulating data suggesting that anti-Dsg autoAbs by themselves cannot adequately explain the loss of cell-cell adhesion seen in PV, nor account for the disease heterogeneity exhibited across PV patients has spurred the notion that additional autoAb specificities may contribute to disease. To investigate the role of non-Dsg autoAbs in PV, an increasing number of studies have attempted to characterize additional targets of PV autoAbs. The recent advent of protein microarray technology, which allows for the rapid, highly sensitive, and multiplexed assessment of autoAb specificity has facilitated the comprehensive classification of the scope and specificity of the autoAb response in PV. Such detailed deconstruction of the autoimmune response in PV, beyond simply tracking anti-Dsg autoAbs, has provided invaluable new insights concerning disease mechanisms and enhanced disease classification which could directly translate into superior tools for prognostics and clinical management, as well as the development of novel, disease specific treatments.
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Affiliation(s)
- Animesh A Sinha
- Department of Dermatology, University at Buffalo, Buffalo, NY, United States
| | - Thomas Sajda
- Department of Dermatology, University at Buffalo, Buffalo, NY, United States
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19
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Ultrastructural changes in endometrial desmosomes of desmoglein 2 mutant mice. Cell Tissue Res 2018; 374:317-327. [PMID: 29938327 DOI: 10.1007/s00441-018-2869-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/25/2018] [Indexed: 10/28/2022]
Abstract
The intercellular binding of desmosomal junctions is mediated by cadherins of the desmoglein (Dsg) and desmocollin (Dsc) type. Dsg2 mutant mice with deletion of a substantial segment of the extracellular EC1-EC2 domain, which is believed to participate in homo- and heterophilic desmosomal cadherin interactions, develop cardiac fibrosis and ventricular dilation. Widening of the intercellular cleft and complete intercalated disc ruptures can be observed in the hearts of these mice. Since a reduced litter size of homozygous Dsg2 mutant mice was noted and a functional correlation between desmosomes and embryo implantation has been deduced from animal studies, we looked for an alteration of desmosomes in uterine endometrial epithelium. Shape and number of desmosomes as well as the expression of Dsg2 and the desmosomal plaque protein desmoplakin (Dsp) were investigated by electron microscopy and immunohistochemistry in 12 oestrous-dated mice (7 wild type and 5 homozygous Dsg2 mutant mice) at the age of 9-17 weeks. The immunohistochemical detection of Dsg2 was diminished in the mutants and the number of desmosomes was significantly reduced as revealed by electron microscopy. In addition, the intercellular desmosomal space measured in electron micrographs was considerably widened in the Dsg2 mutants. The increased intercellular spacing can be explained by the partial deletion of the extracellular EC1-EC2 domain of Dsg2. Whether these changes explain the reduced number of offspring of homozygous Dsg2 mutant mice remains to be further investigated.
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20
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Bartle EI, Rao TC, Urner TM, Mattheyses AL. Bridging the gap: Super-resolution microscopy of epithelial cell junctions. Tissue Barriers 2018; 6:e1404189. [PMID: 29420122 PMCID: PMC5823550 DOI: 10.1080/21688370.2017.1404189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 02/02/2023] Open
Abstract
Cell junctions are critical for cell adhesion and communication in epithelial tissues. It is evident that the cellular distribution, size, and architecture of cell junctions play a vital role in regulating function. These details of junction architecture have been challenging to elucidate in part due to the complexity and size of cell junctions. A major challenge in understanding these features is attaining high resolution spatial information with molecular specificity. Fluorescence microscopy allows localization of specific proteins to junctions, but with a resolution on the same scale as junction size, rendering internal protein organization unobtainable. Super-resolution microscopy provides a bridge between fluorescence microscopy and nanoscale approaches, utilizing fluorescent tags to reveal protein organization below the resolution limit. Here we provide a brief introduction to super-resolution microscopy and discuss novel findings into the organization, structure and function of epithelial cell junctions.
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Affiliation(s)
- Emily I. Bartle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tejeshwar C. Rao
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tara M. Urner
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexa L. Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
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21
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Bartle EI, Urner TM, Raju SS, Mattheyses AL. Desmoglein 3 Order and Dynamics in Desmosomes Determined by Fluorescence Polarization Microscopy. Biophys J 2018; 113:2519-2529. [PMID: 29212005 DOI: 10.1016/j.bpj.2017.09.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/18/2017] [Accepted: 09/21/2017] [Indexed: 11/24/2022] Open
Abstract
Desmosomes are macromolecular cell-cell junctions that provide adhesive strength in epithelial tissue. Desmosome function is inseparably linked to structure, and it is hypothesized that the arrangement, or order, of desmosomal cadherins in the intercellular space is critical for adhesive strength. However, due to desmosome size, molecular complexity, and dynamics, the role that order plays in adhesion is challenging to study. Herein, we present an excitation resolved fluorescence polarization microscopy approach to measure the spatiotemporal dynamics of order and disorder of the desmosomal cadherin desmoglein 3 (Dsg3) in living cells. Simulations were used to establish order factor as a robust metric for quantifying the spatiotemporal dynamics of order and disorder. Order factor measurements in keratinocytes showed the Dsg3 extracellular domain is ordered at the individual desmosome, single cell, and cell population levels compared to a series of disordered controls. Desmosomal adhesion is Ca2+ dependent, and reduction of extracellular Ca2+ leads to a loss of adhesion measured by dispase fragmentation assay (λ = 15.1 min). Live cell imaging revealed Dsg3 order decreased more rapidly (λ = 5.5 min), indicating that cadherin order is not required for adhesion. Our results suggest that rapid disordering of cadherins can communicate a change in extracellular Ca2+ concentration to the cell, leading to a downstream loss of adhesion. Fluorescence polarization is an effective bridge between protein structure and complex dynamics and the approach presented here is broadly applicable to studying order in macromolecular structures.
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Affiliation(s)
- Emily I Bartle
- Department of Cell Biology, Emory University, Atlanta, Georgia
| | - Tara M Urner
- Department of Cell Biology, Emory University, Atlanta, Georgia
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22
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Jones JCR, Kam CY, Harmon RM, Woychek AV, Hopkinson SB, Green KJ. Intermediate Filaments and the Plasma Membrane. Cold Spring Harb Perspect Biol 2017; 9:9/1/a025866. [PMID: 28049646 DOI: 10.1101/cshperspect.a025866] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A variety of intermediate filament (IF) types show intricate association with plasma membrane proteins, including receptors and adhesion molecules. The molecular basis of linkage of IFs to desmosomes at sites of cell-cell interaction and hemidesmosomes at sites of cell-matrix adhesion has been elucidated and involves IF-associated proteins. However, IFs also interact with focal adhesions and cell-surface molecules, including dystroglycan. Through such membrane interactions, it is well accepted that IFs play important roles in the establishment and maintenance of tissue integrity. However, by organizing cell-surface complexes, IFs likely regulate, albeit indirectly, signaling pathways that are key to tissue homeostasis and repair.
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Affiliation(s)
- Jonathan C R Jones
- The School of Molecular Biosciences, Washington State University, Pullman, Washington 99164
| | - Chen Yuan Kam
- Departments of Dermatology and Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Robert M Harmon
- Departments of Dermatology and Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Alexandra V Woychek
- The School of Molecular Biosciences, Washington State University, Pullman, Washington 99164
| | - Susan B Hopkinson
- The School of Molecular Biosciences, Washington State University, Pullman, Washington 99164
| | - Kathleen J Green
- Departments of Dermatology and Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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23
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Celentano A, Mignogna MD, McCullough M, Cirillo N. Pathophysiology of the Desmo-Adhesome. J Cell Physiol 2016; 232:496-505. [PMID: 27505028 DOI: 10.1002/jcp.25515] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 08/08/2016] [Indexed: 01/18/2023]
Abstract
Advances in our understanding of desmosomal diseases have provided a clear demonstration of the key role played by desmosomes in tissue and organ physiology, highlighting the importance of their dynamic and finely regulated structure. In this context, non-desmosomal regulatory molecules have acquired increasing relevance in the study of this organelle resulting in extending the desmosomal interactome, named the "desmo-adhesome." Spatiotemporal changes in the expression and regulation of the desmo-adhesome underlie a number of genetic, infectious, autoimmune, and malignant conditions. The aim of the present article was to examine the structural and functional relationship of the desmosome, by providing a comprehensive, yet focused overview of the constituents targeted in human disease. The inclusion of the novel regulatory network in the desmo-adhesome pathophysiology opens new avenues to a deeper understanding of desmosomal diseases, potentially unveiling pathogenic mechanisms waiting to be explored. J. Cell. Physiol. 232: 496-505, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Antonio Celentano
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University Federico II of Naples, Naples, Italy.,Melbourne Dental School, University of Melbourne, Carlton, Victoria, Australia
| | - Michele Davide Mignogna
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University Federico II of Naples, Naples, Italy
| | - Michael McCullough
- Melbourne Dental School, University of Melbourne, Carlton, Victoria, Australia.,Oral Health Cooperative Research Centre (CRC), University of Melbourne, Carlton, Victoria, Australia
| | - Nicola Cirillo
- Melbourne Dental School, University of Melbourne, Carlton, Victoria, Australia.,Oral Health Cooperative Research Centre (CRC), University of Melbourne, Carlton, Victoria, Australia
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24
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Stahley SN, Bartle EI, Atkinson CE, Kowalczyk AP, Mattheyses AL. Molecular organization of the desmosome as revealed by direct stochastic optical reconstruction microscopy. J Cell Sci 2016; 129:2897-904. [PMID: 27505428 DOI: 10.1242/jcs.185785] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 06/15/2016] [Indexed: 12/14/2022] Open
Abstract
Desmosomes are macromolecular junctions responsible for providing strong cell-cell adhesion. Because of their size and molecular complexity, the precise ultrastructural organization of desmosomes is challenging to study. Here, we used direct stochastic optical reconstruction microscopy (dSTORM) to resolve individual plaque pairs for inner and outer dense plaque proteins. Analysis methods based on desmosomal mirror symmetry were developed to measure plaque-to-plaque distances and create an integrated map. We quantified the organization of desmoglein 3, plakoglobin and desmoplakin (N-terminal, rod and C-terminal domains) in primary human keratinocytes. Longer desmosome lengths correlated with increasing plaque-to-plaque distance, suggesting that desmoplakin is arranged with its long axis at an angle within the plaque. We next examined whether plaque organization changed in different adhesive states. Plaque-to-plaque distance for the desmoplakin rod and C-terminal domains decreased in PKP-1-mediated hyperadhesive desmosomes, suggesting that protein reorganization correlates with function. Finally, in human epidermis we found a difference in plaque-to-plaque distance for the desmoplakin C-terminal domain, but not the desmoplakin rod domain or plakoglobin, between basal and suprabasal cells. Our data reveal the molecular organization of desmosomes in cultured keratinocytes and skin as defined by dSTORM.
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Affiliation(s)
- Sara N Stahley
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Emily I Bartle
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Claire E Atkinson
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Andrew P Kowalczyk
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Dermatology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Alexa L Mattheyses
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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25
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Abstract
Desmosomes are intercellular adhesive junctions that impart strength to vertebrate tissues. Their dense, ordered intercellular attachments are formed by desmogleins (Dsgs) and desmocollins (Dscs), but the nature of trans-cellular interactions between these specialized cadherins is unclear. Here, using solution biophysics and coated-bead aggregation experiments, we demonstrate family-wise heterophilic specificity: All Dsgs form adhesive dimers with all Dscs, with affinities characteristic of each Dsg:Dsc pair. Crystal structures of ectodomains from Dsg2 and Dsg3 and from Dsc1 and Dsc2 show binding through a strand-swap mechanism similar to that of homophilic classical cadherins. However, conserved charged amino acids inhibit Dsg:Dsg and Dsc:Dsc interactions by same-charge repulsion and promote heterophilic Dsg:Dsc interactions through opposite-charge attraction. These findings show that Dsg:Dsc heterodimers represent the fundamental adhesive unit of desmosomes and provide a structural framework for understanding desmosome assembly.
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26
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Stahley SN, Warren MF, Feldman RJ, Swerlick RA, Mattheyses AL, Kowalczyk AP. Super-Resolution Microscopy Reveals Altered Desmosomal Protein Organization in Tissue from Patients with Pemphigus Vulgaris. J Invest Dermatol 2016; 136:59-66. [PMID: 26763424 PMCID: PMC4730957 DOI: 10.1038/jid.2015.353] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/29/2015] [Accepted: 08/17/2015] [Indexed: 12/19/2022]
Abstract
Pemphigus vulgaris (PV) is an autoimmune epidermal blistering disease in which autoantibodies (IgG) are directed against the desmosomal cadherin desmoglein 3 (Dsg3). In order to better understand how PV IgG alters desmosome morphology and function in vivo, PV patient biopsies were analyzed by structured illumination microscopy (SIM), a form of super-resolution fluorescence microscopy. In patient tissue, desmosomal proteins were aberrantly clustered and localized to PV IgG-containing endocytic linear arrays. Patient IgG also colocalized with markers for lipid rafts and endosomes. Additionally, steady-state levels of Dsg3 were decreased and desmosomes were reduced in size in patient tissue. Desmosomes at blister sites were occasionally split, with PV IgG decorating the extracellular faces of split desmosomes. Desmosome splitting was recapitulated in vitro by exposing cultured keratinocytes both to PV IgG and to mechanical stress, demonstrating that splitting at the blister interface in patient tissue is due to compromised desmosomal adhesive function. These findings indicate that Dsg3 clustering and endocytosis are associated with reduced desmosome size and adhesion defects in PV patient tissue. Further, this study reveals that super-resolution optical imaging is powerful approach for studying epidermal adhesion structures in normal and diseased skin.
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Affiliation(s)
- Sara N Stahley
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA; Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Maxine F Warren
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ron J Feldman
- Department of Dermatology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Robert A Swerlick
- Department of Dermatology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Alexa L Mattheyses
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Andrew P Kowalczyk
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA; Department of Dermatology, Emory University School of Medicine, Atlanta, Georgia, USA; Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA.
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27
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28
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Jan A, Basit S, Wakil SM, Ramzan K, Ahmad W. A novel homozygous variant in the dsp gene underlies the first case of non-syndromic form of alopecia. Arch Dermatol Res 2015; 307:793-801. [DOI: 10.1007/s00403-015-1590-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 05/31/2015] [Accepted: 06/29/2015] [Indexed: 02/04/2023]
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29
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Kitajima Y. Implications of normal and disordered remodeling dynamics of corneodesmosomes in stratum corneum. DERMATOL SIN 2015. [DOI: 10.1016/j.dsi.2015.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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30
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Tariq H, Bella J, Jowitt TA, Holmes DF, Rouhi M, Nie Z, Baldock C, Garrod D, Tabernero L. Cadherin flexibility provides a key difference between desmosomes and adherens junctions. Proc Natl Acad Sci U S A 2015; 112:5395-400. [PMID: 25855637 PMCID: PMC4418904 DOI: 10.1073/pnas.1420508112] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Desmosomes and adherens junctions are intercellular adhesive structures essential for the development and integrity of vertebrate tissue, including the epidermis and heart. Their cell adhesion molecules are cadherins: type 1 cadherins in adherens junctions and desmosomal cadherins in desmosomes. A fundamental difference is that desmosomes have a highly ordered structure in their extracellular region and exhibit calcium-independent hyperadhesion, whereas adherens junctions appear to lack such ordered arrays, and their adhesion is always calcium-dependent. We present here the structure of the entire ectodomain of desmosomal cadherin desmoglein 2 (Dsg2), using a combination of small-angle X-ray scattering, electron microscopy, and solution-based biophysical techniques. This structure reveals that the ectodomain of Dsg2 is flexible even in the calcium-bound state and, on average, is shorter than the type 1 cadherin crystal structures. The Dsg2 structure has an excellent fit with the electron tomography reconstructions of human desmosomes. This fit suggests an arrangement in which desmosomal cadherins form trans interactions but are too far apart to interact in cis, in agreement with previously reported observations. Cadherin flexibility may be key to explaining the plasticity of desmosomes that maintain tissue integrity in their hyperadhesive form, but can adopt a weaker, calcium-dependent adhesion during wound healing and early development.
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Affiliation(s)
- Humera Tariq
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Jordi Bella
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Thomas A Jowitt
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - David F Holmes
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Mansour Rouhi
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Zhuxiang Nie
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Clair Baldock
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - David Garrod
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Lydia Tabernero
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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31
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Osmani N, Labouesse M. Remodeling of keratin-coupled cell adhesion complexes. Curr Opin Cell Biol 2014; 32:30-8. [PMID: 25460779 DOI: 10.1016/j.ceb.2014.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/13/2014] [Accepted: 10/18/2014] [Indexed: 12/12/2022]
Abstract
Epithelial cells constitute the main barrier between the inside and outside of organs, acting as gatekeepers of their structure and integrity. Hemidesmosomes and desmosomes are respectively cell-matrix and cell-cell adhesions coupled to the intermediate filament cytoskeleton. These adhesions ensure mechanical integrity of the epithelial barrier. Although desmosomes and hemidesmosomes are essential in maintaining strong cell-cell and cell-matrix adhesions, there is an emerging view that they should be remodeled in order to maintain epithelial homeostasis. Here we review the adhesion properties of desmosomes and hemidesmosomes, as well as the mechanisms driving their remodeling. We also discuss recent data suggesting that keratin-coupled adhesion complexes can sense the biomechanical cellular environment and participate in the cellular response to such external cues.
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Affiliation(s)
- Naël Osmani
- IGBMC, Development and Stem Cells Program, 67400 Illkirch, France; CNRS (UMR 7104), 67400 Illkirch, France; INSERM (U964), 67400 Illkirch, France; Université de Strasbourg, 67400 Illkirch, France.
| | - Michel Labouesse
- IGBMC, Development and Stem Cells Program, 67400 Illkirch, France; CNRS (UMR 7104), 67400 Illkirch, France; INSERM (U964), 67400 Illkirch, France; Université de Strasbourg, 67400 Illkirch, France.
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32
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Abstract
Desmosomes are intercellular junctions that provide strong adhesion or hyper-adhesion in tissues. Here, we discuss the molecular and structural basis of this with particular reference to the desmosomal cadherins (DCs), their isoforms and evolution. We also assess the role of DCs as regulators of epithelial differentiation. New data on the role of desmosomes in development and human disease, especially wound healing and pemphigus, are briefly discussed, and the importance of regulation of the adhesiveness of desmosomes in tissue dynamics is considered.
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Affiliation(s)
- Mohamed Berika
- Department of Anatomy, Faculty of Medicine, Mansoura University , Mansoura City , Egypt
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33
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Plasticity of Mammary Cell Boundaries Governed by EGF and Actin Remodeling. Cell Rep 2014; 8:1722-1730. [DOI: 10.1016/j.celrep.2014.08.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/01/2014] [Accepted: 08/12/2014] [Indexed: 11/20/2022] Open
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34
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Kitajima Y. 150(th) anniversary series: Desmosomes and autoimmune disease, perspective of dynamic desmosome remodeling and its impairments in pemphigus. ACTA ACUST UNITED AC 2014; 21:269-80. [PMID: 25078507 DOI: 10.3109/15419061.2014.943397] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Desmosomes are the most important intercellular adhering junctions that adhere two adjacent keratinocytes directly with desmosomal cadherins, that is, desmogleins (Dsgs) and desmocollins, forming an epidermal sheet. Recently, two cell-cell adhesion states of desmosomes, that is, "stable hyper-adhesion" and "dynamic weak-adhesion" conditions have been recognized. They are mutually reversible through cell signaling events involving protein kinase C (PKC), Src and epidermal growth factor receptor (EGFR) during Ca(2+)-switching and wound healing. This remodeling is impaired in pemphigus vulgaris (PV, an autoimmune blistering disease), caused by anti-Dsg3 antibodies. The antibody binding to Dsg3 activates PKC, Src and EGFR, linked to generation of dynamic weak-adhesion desmosomes, followed by p38MAPK-mediated endocytosis of Dsg3, resulting in the specific depletion of Dsg3 from desmosomes and acantholysis. A variety of pemphigus outside-in signaling may explain different clinical (non-inflammatory, inflammatory, and necrolytic) types of pemphigus. Pemphigus could be referred to a "desmosome-remodeling disease involving pemphigus IgG-activated outside-in signaling events".
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Affiliation(s)
- Yasuo Kitajima
- Department of Dermatology, Kizawa Memorial Hospital, Professor Emeritus Gifu University School of Medicine , Minokamo City, Gifu Prefecture , Japan
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35
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Abstract
Desmosomes are morphologically and biochemically defined cell-cell junctions that are required for maintaining the mechanical integrity of skin and the heart in adult mammals. Furthermore, since mice with null mutations in desmosomal plaque proteins (plakoglobin and desmoplakin) die in utero, it is also evident that desmosomes are indispensable for normal embryonic development. This review focuses on the role of desmosomes in vivo. We will summarize the effects of mutations in desmosomal genes on pre- and post-embryonic development of mouse and man and discuss recent findings relating to the specific role of desmosomal cadherins in skin differentiation and homeostasis.
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Affiliation(s)
- Xing Cheng
- Department of Dermatology, Baylor College of Medicine, Houston, TX 77030, USA
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36
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Abstract
Hyper-adhesion is a unique, strongly adhesive form of desmosomal adhesion that functions to maintain tissue integrity. In this short review, we define hyper-adhesion, summarise the evidence for it in culture and in vivo, discuss its role in development, wound healing, and skin disease, and speculate about its molecular and cellular basis.
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Affiliation(s)
- David Garrod
- Faculty of Life Sciences, University of Manchester , Manchester , UK
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37
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Le NA, Katsuyama M, Demura M, Tanii H, Katsuyama H, Saijoh K. Regulation of serine protease inhibitor Kazal type-5 (SPINK5) gene expression in the keratinocytes. Environ Health Prev Med 2014; 19:307-13. [PMID: 24894987 PMCID: PMC4085257 DOI: 10.1007/s12199-014-0393-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/02/2014] [Indexed: 12/31/2022] Open
Abstract
Objectives Serine protease inhibitor Kazal type-5 (SPINK5)
plays a crucial role in deciding the timing of desquamation of the skin. Its gene expression is limited at the very surface of the stratum granulosum (SG), whereas expression of kallikreins (KLKs) encoding proteases is usually found throughout the stratum spinosum and SG. Methods To explore the difference in expression regulation of these proteases/inhibitors, the function of SPINK5 promoter was examined using luciferase assay. Results Luciferase assay targeting the SPINK5 promoters (nucleotide −676/−532 and −318/−146 from the major transcription start site) showed high intensity in NHEK human keratinocyte. These two sites had neither common cis-elements nor GATA3 element but electrophoretic mobility shift assay showed similar retardation bands. Moreover, DNA footprinting did not display specific protected bands. Thus, we could not identify cis-element(s) that controlled these elements. Differentiation induced by high Ca2+ medium failed to alter their luciferase activities. Transfection of GATA3 expressing vector significantly but slightly increased them and that of vector expressing its dominant negative form decreased. Conclusions Although GATA3 is reportedly important for inhibition of proliferation and induction of differentiation of keratinocytes, its effect on SPINK5 expression was indirect and GATA3 alone was insufficient for final differentiation of keratinocytes where full SPINK5 expression was observed.
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Affiliation(s)
- Ngoc Anh Le
- Department of Hygiene, Kanazawa University School of Medicine, Kanazawa, 9208640, Japan
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38
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Lowndes M, Rakshit S, Shafraz O, Borghi N, Harmon RM, Green KJ, Sivasankar S, Nelson WJ. Different roles of cadherins in the assembly and structural integrity of the desmosome complex. J Cell Sci 2014; 127:2339-50. [PMID: 24610950 DOI: 10.1242/jcs.146316] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adhesion between cells is established by the formation of specialized intercellular junctional complexes, such as desmosomes. Desmosomes contain isoforms of two members of the cadherin superfamily of cell adhesion proteins, desmocollins (Dsc) and desmogleins (Dsg), but their combinatorial roles in desmosome assembly are not understood. To uncouple desmosome assembly from other cell-cell adhesion complexes, we used micro-patterned substrates of Dsc2aFc and/or Dsg2Fc and collagen IV; we show that Dsc2aFc, but not Dsg2Fc, was necessary and sufficient to recruit desmosome-specific desmoplakin into desmosome puncta and produce strong adhesive binding. Single-molecule force spectroscopy showed that monomeric Dsc2a, but not Dsg2, formed Ca(2+)-dependent homophilic bonds, and that Dsg2 formed Ca(2+)-independent heterophilic bonds with Dsc2a. A W2A mutation in Dsc2a inhibited Ca(2+)-dependent homophilic binding, similar to classical cadherins, and Dsc2aW2A, but not Dsg2W2A, was excluded from desmosomes in MDCK cells. These results indicate that Dsc2a, but not Dsg2, is required for desmosome assembly through homophilic Ca(2+)- and W2-dependent binding, and that Dsg2 might be involved later in regulating a switch to Ca(2+)-independent adhesion in mature desmosomes.
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Affiliation(s)
- Molly Lowndes
- Cancer Biology Program, Stanford University, Stanford, CA 94305, USA
| | - Sabyasachi Rakshit
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA Ames Laboratory, United States Department of Energy, Ames, IA 50011, USA
| | - Omer Shafraz
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA Ames Laboratory, United States Department of Energy, Ames, IA 50011, USA
| | - Nicolas Borghi
- Institut Jacques Monod, Unité Mixte de Recherche 7592, Centre National de la Recherche Scientifique, and Université Paris-Diderot, 75013 Paris, France
| | - Robert M Harmon
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kathleen J Green
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Sanjeevi Sivasankar
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA Ames Laboratory, United States Department of Energy, Ames, IA 50011, USA
| | - W James Nelson
- Cancer Biology Program, Stanford University, Stanford, CA 94305, USA Department of Biology, Stanford University, Stanford, CA 94305, USA Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
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39
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Hatzfeld M, Wolf A, Keil R. Plakophilins in Desmosomal Adhesion and Signaling. ACTA ACUST UNITED AC 2014; 21:25-42. [DOI: 10.3109/15419061.2013.876017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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40
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Abstract
Desmosomes anchor intermediate filaments at sites of cell contact established by the interaction of cadherins extending from opposing cells. The incorporation of cadherins, catenin adaptors, and cytoskeletal elements resembles the closely related adherens junction. However, the recruitment of intermediate filaments distinguishes desmosomes and imparts a unique function. By linking the load-bearing intermediate filaments of neighboring cells, desmosomes create mechanically contiguous cell sheets and, in so doing, confer structural integrity to the tissues they populate. This trait and a well-established role in human disease have long captured the attention of cell biologists, as evidenced by a publication record dating back to the mid-1860s. Likewise, emerging data implicating the desmosome in signaling events pertinent to organismal development, carcinogenesis, and genetic disorders will secure a prominent role for desmosomes in future biological and biomedical investigations.
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Affiliation(s)
- Robert M Harmon
- Department of Pathology, Northwestern University Feinberg, School of Medicine , Chicago, IL , USA
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41
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Al-Jassar C, Bikker H, Overduin M, Chidgey M. Mechanistic basis of desmosome-targeted diseases. J Mol Biol 2013; 425:4006-22. [PMID: 23911551 PMCID: PMC3807649 DOI: 10.1016/j.jmb.2013.07.035] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 11/21/2022]
Abstract
Desmosomes are dynamic junctions between cells that maintain the structural integrity of skin and heart tissues by withstanding shear forces. Mutations in component genes cause life-threatening conditions including arrhythmogenic right ventricular cardiomyopathy, and desmosomal proteins are targeted by pathogenic autoantibodies in skin blistering diseases such as pemphigus. Here, we review a set of newly discovered pathogenic alterations and discuss the structural repercussions of debilitating mutations on desmosomal proteins. The architectures of native desmosomal assemblies have been visualized by cryo-electron microscopy and cryo-electron tomography, and the network of protein domain interactions is becoming apparent. Plakophilin and desmoplakin mutations have been discovered to alter binding interfaces, structures, and stabilities of folded domains that have been resolved by X-ray crystallography and NMR spectroscopy. The flexibility within desmoplakin has been revealed by small-angle X-ray scattering and fluorescence assays, explaining how mechanical stresses are accommodated. These studies have shown that the structural and functional consequences of desmosomal mutations can now begin to be understood at multiple levels of spatial and temporal resolution. This review discusses the recent structural insights and raises the possibility of using modeling for mechanism-based diagnosis of how deleterious mutations alter the integrity of solid tissues.
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Affiliation(s)
- Caezar Al-Jassar
- School of Cancer Sciences, University of Birmingham, Birmingham B15 2TT, UK
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Koga H, Tsuruta D, Ohyama B, Ishii N, Hamada T, Ohata C, Furumura M, Hashimoto T. Desmoglein 3, its pathogenecity and a possibility for therapeutic target in pemphigus vulgaris. Expert Opin Ther Targets 2013; 17:293-306. [DOI: 10.1517/14728222.2013.744823] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Brown AF, Sirohi D, Fukuoka J, Cagle PT, Policarpio-Nicolas M, Tacha D, Jagirdar J. Tissue-preserving antibody cocktails to differentiate primary squamous cell carcinoma, adenocarcinoma, and small cell carcinoma of lung. Arch Pathol Lab Med 2013; 137:1274-81. [PMID: 23289761 DOI: 10.5858/arpa.2012-0635-oa] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT With the availability of cell type-specific therapies, differentiating primary lung squamous cell carcinomas (SCCs) and adenocarcinomas (ACAs) has become important. The limitations of small sample size and the need to conserve tissue for additional molecular studies necessitate the use of sensitive and specific marker panels on a single slide. OBJECTIVE To distinguish SCC from ACA and small cell carcinoma (SmCC) of lung using 2 novel tissue-conserving cocktails. DESIGN We compared two antibody cocktails, desmoglein 3 + cytokeratin 5/napsin A and p40/thyroid transcription factor 1 (Biocare Medical, Concord, California) in diagnosing SCC and ACA of the lung on tissue microarray, cytology, and surgical specimens. Both lung and nonlung tissue were evaluated on an 1150-core tissue microarray that contained 200 lung cancers. A microarray of 35 SmCCs and 5 small cell SCCs was also evaluated. RESULTS A cocktail of desmoglein 3 + cytokeratin 5/napsin A provided diagnostic accuracy in lung cancers with a sensitivity and specificity of 100% in SCCs and a sensitivity of 86% and a specificity of 100% in ACAs. A p40/thyroid transcription factor 1 cocktail showed p40 to have a specificity of 92% and a sensitivity of 93% in SCCs, whereas thyroid transcription factor 1 had a specificity of 100% and a sensitivity of 77% in ACAs. Cell blocks of fine-needle aspiration cytology compared with corresponding surgical (n = 20) specimens displayed similar findings. The p40 was useful in differentiating bladder from prostate carcinoma with 88% sensitivity. Isolated carcinomas from nonlung tissues were desmoglein 3 + cytokeratin 5 positive. Napsin A was positive in 22% of renal tumors as previously observed. Both cocktails were excellent in differentiating SmCCs and small cell SCCs because none of the SmCCs stained with p40. CONCLUSIONS Both antibody cocktails are excellent in differentiating primary lung ACA from SCC, as well as excluding SmCC and ACAs from all other sites on small specimens. A cocktail of desmoglein 3 + cytokeratin 5/napsin A is slightly superior compared with p40/thyroid transcription factor 1 cocktail.
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Affiliation(s)
- Alan F Brown
- Department of Pathology, University of Texas Health Science Center at San Antonio, 78229, USA
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Kitajima Y. New insights into desmosome regulation and pemphigus blistering as a desmosome-remodeling disease. Kaohsiung J Med Sci 2013; 29:1-13. [DOI: 10.1016/j.kjms.2012.08.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Accepted: 02/29/2012] [Indexed: 11/15/2022] Open
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Kowalczyk AP, Green KJ. Structure, function, and regulation of desmosomes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 116:95-118. [PMID: 23481192 DOI: 10.1016/b978-0-12-394311-8.00005-4] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Desmosomes are adhesive intercellular junctions that mechanically integrate adjacent cells by coupling adhesive interactions mediated by desmosomal cadherins to the intermediate filament cytoskeletal network. Desmosomal cadherins are connected to intermediate filaments by densely clustered cytoplasmic plaque proteins comprising members of the armadillo gene family, including plakoglobin and plakophilins, and members of the plakin family of cytolinkers, such as desmoplakin. The importance of desmosomes in tissue integrity is highlighted by human diseases caused by mutations in desmosomal genes, autoantibody attack of desmosomal cadherins, and bacterial toxins that selectively target desmosomal cadherins. In addition to reviewing the well-known roles of desmosomal proteins in tissue integrity, this chapter also highlights the growing appreciation for how desmosomal proteins are integrated with cell signaling pathways to contribute to vertebrate tissue organization and differentiation.
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Affiliation(s)
- Andrew P Kowalczyk
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
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Insights into the role of cell-cell junctions in physiology and disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:187-221. [PMID: 24016526 DOI: 10.1016/b978-0-12-407694-5.00005-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Contacting cells establish different classes of intricate structures at the cell-cell junctions. These structures are of increasing research interest as they regulate a broad variety of processes in development and disease. Further, in vitro studies are revealing that various cell-cell interaction proteins are involved not only in cell-cell processes but also in many additional aspects of physiology, such as migration and apoptosis. This chapter reviews the basic classification of cell-cell junctional structures and some of their representative proteins. Their roles in development and disease are briefly outlined, followed by a section on contemporary methods for probing cell-cell interactions and some recent developments. This chapter concludes with a few suggestions for potential research directions to further develop this promising area of study.
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Saito M, Tucker DK, Kohlhorst D, Niessen CM, Kowalczyk AP. Classical and desmosomal cadherins at a glance. J Cell Sci 2012; 125:2547-52. [PMID: 22833291 DOI: 10.1242/jcs.066654] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Masataka Saito
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
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Abstract
Desmosomes are intercellular adhesive junctions that are particularly prominent in tissues experiencing mechanical stress, such as the heart and epidermis. Whereas the related adherens junction links actin to calcium-dependent adhesion molecules known as classical cadherins, desmosomes link intermediate filaments (IF) to the related subfamily of desmosomal cadherins. By tethering these stress-bearing cytoskeletal filaments to the plasma membrane, desmosomes serve as integrators of the IF cytoskeleton throughout a tissue. Recent evidence suggests that IF attachment in turn strengthens desmosomal adhesion. This collaborative arrangement results in formation of a supracellular network, which is critical for imparting mechanical integrity to tissues. Diseases and animal models targeting desmosomal components highlight the importance of desmosomes in development and tissue integrity, while the downregulation of individual protein components in cancer metastasis and wound healing suggests their importance in cell homeostasis. This chapter will provide an update on desmosome composition, function, and regulation, and will also discuss recent work which raises the possibility that desmosome proteins do more than play a structural role in tissues where they reside.
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Thomason HA, Cooper NH, Ansell DM, Chiu M, Merrit AJ, Hardman MJ, Garrod DR. Direct evidence that PKCα positively regulates wound re-epithelialization: correlation with changes in desmosomal adhesiveness. J Pathol 2012; 227:346-56. [PMID: 22407785 DOI: 10.1002/path.4016] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 02/03/2012] [Accepted: 02/24/2012] [Indexed: 12/17/2022]
Abstract
Non-healing wounds cause considerable patient morbidity and represent a significant economic burden. Central to wound repair is re-epithelialization, a crucial process involving the modulation of cell adhesion to allow keratinocyte migration to cover the exposed underlying tissues. The cellular mechanisms regulating the earliest stages of re-epithelialization are unclear. We present the first direct evidence that protein kinase Cα (PKCα) plays an important role in regulating wound re-epithelialization. In PKCα(-/-) mice re-epithelialization is delayed, while in novel bitransgenic mice over-expressing constitutively active PKCα it is accelerated. These effects are not due to changes in keratinocyte proliferation, apoptosis or intrinsic cell motility. Instead, they correlate with changes in desmosomal adhesiveness, delay being preceded by retained desmosomal hyper-adhesiveness and acceleration with a rapid switch to desmosomal Ca(2+) -dependence. We demonstrate mechanistic conservation in acute human wounds where PKCα localizes to wound edge desmosomes, which become Ca(2+) -dependent. However, in chronic wounds PKCα remains cytoplasmic and desmosomes fail to switch from the hyper-adhesive state. These results throw new mechanistic light on the earliest stages of wound re-epithelialization and suggest activation of PKCα as a new therapeutic strategy for non-healing wounds.
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Rickelt S. Plakophilin-2: a cell-cell adhesion plaque molecule of selective and fundamental importance in cardiac functions and tumor cell growth. Cell Tissue Res 2012; 348:281-94. [PMID: 22281687 PMCID: PMC3349858 DOI: 10.1007/s00441-011-1314-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 12/16/2011] [Indexed: 01/23/2023]
Abstract
Within the characteristic ensemble of desmosomal plaque proteins, the armadillo protein plakophilin-2 (Pkp2) is known as a particularly important regulatory component in the cytoplasmic plaques of various other cell-cell junctions, such as the composite junctions (areae compositae) of the myocardiac intercalated disks and in the variously-sized and -shaped complex junctions of permanent cell culture lines derived therefrom. In addition, Pkp2 has been detected in certain protein complexes in the nucleoplasm of diverse kinds of cells. Using a novel set of highly sensitive and specific antibodies, both kinds of Pkp2, the junctional plaque-bound and the nuclear ones, can also be localized to the cytoplasmic plaques of diverse non-desmosomal cell-cell junction structures. These are not only the puncta adhaerentia and the fasciae adhaerentes connecting various types of highly proliferative non-epithelial cells growing in culture but also some very proliferative states of cardiac interstitial cells and cardiac myxomata, including tumors growing in situ as well as fetal stages of heart development and cultures of valvular interstitial cells. Possible functions and assembly mechanisms of such Pkp2-positive cell-cell junctions as well as medical consequences are discussed.
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Affiliation(s)
- Steffen Rickelt
- Helmholtz Group for Cell Biology, German Cancer Research Center, Heidelberg, Germany.
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