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Apremilast prevents blistering in human epidermis and stabilizes keratinocyte adhesion in pemphigus. Nat Commun 2023; 14:116. [PMID: 36624106 PMCID: PMC9829900 DOI: 10.1038/s41467-022-35741-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/21/2022] [Indexed: 01/10/2023] Open
Abstract
Pemphigus vulgaris is a life-threatening blistering skin disease caused by autoantibodies destabilizing desmosomal adhesion. Current therapies focus on suppression of autoantibody formation and thus treatments directly stabilizing keratinocyte adhesion would fulfill an unmet medical need. We here demonstrate that apremilast, a phosphodiesterase 4 inhibitor used in psoriasis, prevents skin blistering in pemphigus vulgaris. Apremilast abrogates pemphigus autoantibody-induced loss of keratinocyte cohesion in ex-vivo human epidermis, cultured keratinocytes in vitro and in vivo in mice. In parallel, apremilast inhibits keratin retraction as well as desmosome splitting, induces phosphorylation of plakoglobin at serine 665 and desmoplakin assembly into desmosomal plaques. We established a plakoglobin phospho-deficient mouse model that reveals fragile epidermis with altered organization of keratin filaments and desmosomal cadherins. In keratinocytes derived from these mice, intercellular adhesion is impaired and not rescued by apremilast. These data identify an unreported mechanism of desmosome regulation and propose that apremilast stabilizes keratinocyte adhesion and is protective in pemphigus.
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Radine UK, Bumiller-Bini Hoch V, Boldt ABW, Zillikens D, Ludwig RJ, Hammers CM, Klinger M, Hundt JE. Electron microscopy of desmosomal structures in the pemphigus human skin organ culture model. Front Med (Lausanne) 2022; 9:997387. [DOI: 10.3389/fmed.2022.997387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/18/2022] [Indexed: 11/15/2022] Open
Abstract
Pemphigus is a chronic autoimmune skin blistering disease, characterized by acantholysis and by the production of autoantibodies directed against the structural desmosomal proteins desmoglein 1 (DSG1) and/or DSG3. Model systems allow the identification and testing of new therapeutic targets. Here, we evaluated ultrastructural desmosomal morphology in the human skin organ culture (HSOC) model injected with either anti-desmoglein (DSG) 1/3 single-chain variable fragment (scFv, termed Px4-3), Staphylococcus aureus exfoliative toxin (ETA) as a reference and positive control, and normal human IgG as a negative control. Each experimental condition was evaluated in abdominal skin biopsies from five different donors. After 24 h of incubation, we processed the samples for histological and ultrastructural electron microscopy analyses. We found that Px4-3 or ETA induced a loss of desmosomes and increased interdesmosomal widening, similar to patient skin biopsies and other pemphigus models. Thus, we propose the HSOC pemphigus model as an attractive tool to unravel novel therapeutic targets.
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Egu DT, Schmitt T, Sigmund AM, Waschke J. Electron microscopy reveals that phospholipase C and Ca2+ signaling regulate keratin filament uncoupling from desmosomes in Pemphigus. Ann Anat 2022; 241:151904. [DOI: 10.1016/j.aanat.2022.151904] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 12/27/2022]
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Schmitt T, Waschke J. Autoantibody-Specific Signalling in Pemphigus. Front Med (Lausanne) 2021; 8:701809. [PMID: 34434944 PMCID: PMC8381052 DOI: 10.3389/fmed.2021.701809] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 07/08/2021] [Indexed: 12/11/2022] Open
Abstract
Pemphigus is a severe autoimmune disease impairing barrier functions of epidermis and mucosa. Autoantibodies primarily target the desmosomal adhesion molecules desmoglein (Dsg) 1 and Dsg 3 and induce loss of desmosomal adhesion. Strikingly, autoantibody profiles in pemphigus correlate with clinical phenotypes. Mucosal-dominant pemphigus vulgaris (PV) is characterised by autoantibodies (PV-IgG) against Dsg3 whereas epidermal blistering in PV and pemphigus foliaceus (PF) is associated with autoantibodies against Dsg1. Therapy in pemphigus is evolving towards specific suppression of autoantibody formation and autoantibody depletion. Nevertheless, during the acute phase and relapses of the disease additional treatment options to stabilise desmosomes and thereby rescue keratinocyte adhesion would be beneficial. Therefore, the mechanisms by which autoantibodies interfere with adhesion of desmosomes need to be characterised in detail. Besides direct inhibition of Dsg adhesion, autoantibodies engage signalling pathways interfering with different steps of desmosome turn-over. With this respect, recent data indicate that autoantibodies induce separate signalling responses in keratinocytes via specific signalling complexes organised by Dsg1 and Dsg3 which transfer the signal of autoantibody binding into the cell. This hypothesis may also explain the different clinical pemphigus phenotypes.
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Affiliation(s)
- Thomas Schmitt
- Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Munich, Germany
| | - Jens Waschke
- Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Munich, Germany
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Schmitt T, Egu DT, Walter E, Sigmund AM, Eichkorn R, Yazdi A, Schmidt E, Sárdy M, Eming R, Goebeler M, Waschke J. Ca 2+ signalling is critical for autoantibody-induced blistering of human epidermis in pemphigus. Br J Dermatol 2021; 185:595-604. [PMID: 33792909 DOI: 10.1111/bjd.20091] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND Pemphigus is a severe bullous autoimmune skin disease. Pemphigus foliaceus (PF) is characterized by antidesmoglein (Dsg) 1 IgG causing epidermal blistering; mucosal pemphigus vulgaris (mPV) by anti-Dsg3 IgG inducing erosions in the mucosa; and mucocutaneous pemphigus vulgaris (PV) by affecting both, with autoantibodies targeting Dsg1 and Dsg3. OBJECTIVES To characterize the Ca2+ flux pathway and delineate its importance in pemphigus pathogenesis and clinical phenotypes caused by different antibody profiles. METHODS Immunoprecipitation, Ca2+ flux analysis, Western blotting, immunofluorescence staining, dissociation assays and a human skin ex vivo model were used. RESULTS PV IgG and PF IgG, but neither Dsg3-specific monoclonal antibody (AK23) nor mPV IgG, caused Ca2+ influx in primary human keratinocytes. Phosphatidylinositol 4-kinase α interacts with Dsg1 but not with Dsg3. Its downstream target - phospholipase-C-γ1 (PLC) - was activated by PV IgG and PF IgG but not AK23 or mPV IgG. PLC releases inositol 1,4,5-trisphosphate (IP3) causing IP3 receptor (IP3R) activation and Ca2+ flux from the endoplasmic reticulum into the cytosol, which stimulates Ca2+ release-activated channels (CRAC)-mediated Ca2+ influx. Inhibitors against PLC, IP3R and CRAC effectively blocked PV IgG and PF IgG-induced Ca2+ influx; ameliorated alterations of Dsg1 and Dsg3 localization, and reorganization of keratin and actin filaments; and inhibited loss of cell adhesion in vitro. Finally, inhibiting PLC or IP3R was protective against PV IgG-induced blister formation and redistribution of Dsg1 and Dsg3 in human skin ex vivo. CONCLUSIONS Ca2+ -mediated signalling is important for epidermal blistering and dependent on the autoantibody profile, which indicates different roles for signalling complexes organized by Dsg1 and Dsg3. Interfering with PLC and Ca2+ signalling may be a promising approach to treat epidermal manifestations of pemphigus.
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Affiliation(s)
- T Schmitt
- Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Pettenkoferstraße 11, München, D-80336, Germany
| | - D T Egu
- Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Pettenkoferstraße 11, München, D-80336, Germany
| | - E Walter
- Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Pettenkoferstraße 11, München, D-80336, Germany
| | - A M Sigmund
- Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Pettenkoferstraße 11, München, D-80336, Germany
| | - R Eichkorn
- Department of Dermatology, University Medical Center Tübingen, Eberhard Karls-University, Tübingen, Germany
| | - A Yazdi
- Department of Dermatology, University Medical Center Tübingen, Eberhard Karls-University, Tübingen, Germany.,Department of Dermatology, RWTH Aachen, Aachen, Germany
| | - E Schmidt
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, 23562, Germany.,Department of Dermatology, University of Lübeck, Lübeck, 23562, Germany
| | - M Sárdy
- Clinic for Dermatology, Semmelweis University, Budapest, Hungary
| | - R Eming
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany
| | - M Goebeler
- Department of Dermatology, Venereology and Allergology, University Hospital Würzburg, Würzburg, 97080, Germany
| | - J Waschke
- Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Pettenkoferstraße 11, München, D-80336, Germany
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Rashid H, Lamberts A, Diercks GFH, Pas HH, Meijer JM, Bolling MC, Horváth B. Oral Lesions in Autoimmune Bullous Diseases: An Overview of Clinical Characteristics and Diagnostic Algorithm. Am J Clin Dermatol 2019; 20:847-861. [PMID: 31313078 PMCID: PMC6872602 DOI: 10.1007/s40257-019-00461-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Autoimmune bullous diseases are a group of chronic inflammatory disorders caused by autoantibodies targeted against structural proteins of the desmosomal and hemidesmosomal plaques in the skin and mucosa, leading to intra-epithelial or subepithelial blistering. The oral mucosa is frequently affected in these diseases, in particular, in mucous membrane pemphigoid, pemphigus vulgaris, and paraneoplastic pemphigus. The clinical symptoms are heterogeneous and may present with erythema, blisters, erosions, and ulcers localized anywhere on the oral mucosa, and lead to severe complaints for the patients including pain, dysphagia, and foetor. Therefore, a quick and proper diagnosis with adequate treatment is needed. Clinical presentations of autoimmune bullous diseases often overlap and diagnosis cannot be made based on clinical features alone. Immunodiagnostic tests are of great importance in differentiating between the different diseases. Direct immunofluorescence microscopy shows depositions of autoantibodies along the epithelial basement membrane zone in mucous membrane pemphigoid subtypes, or depositions on the epithelial cell surface in pemphigus variants. Additional immunoserological tests are useful to discriminate between the different subtypes of pemphigoid, and are essential to differentiate between pemphigus and paraneoplastic pemphigus. This review gives an overview of the clinical characteristics of oral lesions and the diagnostic procedures in autoimmune blistering diseases, and provides a diagnostic algorithm for daily practice.
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Affiliation(s)
- Hanan Rashid
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands.
| | - Aniek Lamberts
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands
| | - Gilles F H Diercks
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands
- Department of Pathology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Hendri H Pas
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands
| | - Joost M Meijer
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands
| | - Maria C Bolling
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands
| | - Barbara Horváth
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands
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Oktarina DAM, Sokol E, Kramer D, Jonkman MF, Pas HH. Endocytosis of IgG, Desmoglein 1, and Plakoglobin in Pemphigus Foliaceus Patient Skin. Front Immunol 2019; 10:2635. [PMID: 31781120 PMCID: PMC6861377 DOI: 10.3389/fimmu.2019.02635] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 10/24/2019] [Indexed: 01/29/2023] Open
Abstract
Pemphigus foliaceus (PF) is one of the two main forms of pemphigus and is characterized by circulating IgG to the desmosomal cadherin desmoglein 1 (DSG1) and by subcorneal blistering of the skin. The pathomechanism of blister formation in PF is unknown. Previously we have shown that PF IgG induces aggregation of DSG1, plakoglobin (PG), and IgG outside of desmosomes, what in immunofluorescence of PF patient skin visualizes as a granular IgG deposition pattern with a limited number of coarse IgG aggregates between cells. Here we have investigated the fate of these aggregates in skin and found that these are cleared by endocytosis. We performed double immunofluorescence staining on snap-frozen skin biopsies of six PF patients for the following molecules: IgG, the desmosomal proteins DSG1 and DSG3, desmocollins 1 and 3, PG, desmoplakin and plakophilin 3, and for the endosomal marker early endosomal antigen 1 and the lysosomal markers cathepsin D and lysosomal-associated membrane protein 1. Endosomes were present in all cells but did not make contact with the aggregates in the basal and suprabasal layers. In the higher layers they moored to the aggregates, often symmetrically from two adjacent cells, and IgG, DSG1, and PG were taken up. Finally these endosomes became localized perinuclear. Endocytosis was only observed in perilesional or lesional skin but not in non-lesional skin. Older immunoelectron microscopic studies have suggested that in PF skin endocytosis of detached desmosomes takes place but we found no other desmosomal proteins to be present in these endosomes. Double staining with cathepsin D and LAMP-1 revealed no overlap with IgG, DSG1, or PG suggesting that lysosomes have no role in the clearing process. Collectively, our results show that endocytosis is part of the pathogenic process in PF but that no detached desmosomes are taken up but instead the deposited IgG is taken up together with DSG1 and PG.
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Affiliation(s)
- Dyah A M Oktarina
- Department of Dermatology, Centre for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands.,Department of Dermatology and Venereology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Ena Sokol
- Department of Dermatology, Centre for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Duco Kramer
- Department of Dermatology, Centre for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Marcel F Jonkman
- Department of Dermatology, Centre for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Hendri H Pas
- Department of Dermatology, Centre for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
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8
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Fuchs M, Foresti M, Radeva MY, Kugelmann D, Keil R, Hatzfeld M, Spindler V, Waschke J, Vielmuth F. Plakophilin 1 but not plakophilin 3 regulates desmoglein clustering. Cell Mol Life Sci 2019; 76:3465-3476. [PMID: 30949721 PMCID: PMC11105395 DOI: 10.1007/s00018-019-03083-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 02/15/2019] [Accepted: 03/25/2019] [Indexed: 12/25/2022]
Abstract
Plakophilins (Pkp) are desmosomal plaque proteins crucial for desmosomal adhesion and participate in the regulation of desmosomal turnover and signaling. However, direct evidence that Pkps regulate clustering and molecular binding properties of desmosomal cadherins is missing. Here, keratinocytes lacking either Pkp1 or 3 in comparison to wild type (wt) keratinocytes were characterized with regard to their desmoglein (Dsg) 1- and 3-binding properties and their capability to induce Dsg3 clustering. As revealed by atomic force microscopy (AFM), both Pkp-deficient keratinocyte cell lines showed reduced membrane availability and binding frequency of Dsg1 and 3 at cell borders. Extracellular crosslinking and AFM cluster mapping demonstrated that Pkp1 but not Pkp3 is required for Dsg3 clustering. Accordingly, Dsg3 overexpression reconstituted cluster formation in Pkp3- but not Pkp1-deficient keratinocytes as shown by AFM and STED experiments. Taken together, these data demonstrate that both Pkp1 and 3 regulate Dsg membrane availability, whereas Pkp1 but not Pkp3 is required for Dsg3 clustering.
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Affiliation(s)
- Michael Fuchs
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 11, 80336, Munich, Germany
| | - Marco Foresti
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 11, 80336, Munich, Germany
| | - Mariya Y Radeva
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 11, 80336, Munich, Germany
| | - Daniela Kugelmann
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 11, 80336, Munich, Germany
| | - Rene Keil
- Division of Pathobiochemistry, Institute of Molecular Medicine, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Mechthild Hatzfeld
- Division of Pathobiochemistry, Institute of Molecular Medicine, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Volker Spindler
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Jens Waschke
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 11, 80336, Munich, Germany.
| | - Franziska Vielmuth
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 11, 80336, Munich, Germany.
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9
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Walter E, Vielmuth F, Wanuske MT, Seifert M, Pollmann R, Eming R, Waschke J. Role of Dsg1- and Dsg3-Mediated Signaling in Pemphigus Autoantibody-Induced Loss of Keratinocyte Cohesion. Front Immunol 2019; 10:1128. [PMID: 31178865 PMCID: PMC6543754 DOI: 10.3389/fimmu.2019.01128] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/03/2019] [Indexed: 12/13/2022] Open
Abstract
Pemphigus is an autoimmune dermatosis in which mucocutaneous blisters are induced primarily by autoantibodies against Desmoglein (Dsg) 1 and 3. Pemphigus vulgaris (PV) usually is associated with autoantibodies against Dsg3 whereas pemphigus foliaceus (PF) patients present autoantibodies against Dsg1. Several signaling pathways were proposed to cause loss of keratinocyte adhesion. However, relevance of different signaling pathways and role of Dsg1 and 3 to trigger signaling are not fully understood. Here, we show that Ca2+ chelation reduced PV-IgG- and PF-IgG-mediated loss of HaCaT keratinocyte cohesion whereas EGFR inhibition did not inhibit effects of PF-IgG. PV-IgG activated EGFR in a Src-dependent manner whereas both PV-IgG and PF-IgG caused Ca2+ influx independent of EGFR. ERK activation was Src-dependent in response to PV-IgG but not PF-IgG. To delineate the roles of Dsg isoforms to trigger signaling pathways, Dsg3- and Dsg2-deficient HaCaT keratinocyte cell lines were generated using CRISPR/Cas9. Dsg3- but not Dsg2-deficient cells were protected against PV-IgG-induced loss of cell adhesion. Ca2+ influx and ERK activation in response to PF-IgG were preserved in both cell lines.
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Affiliation(s)
- Elias Walter
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Franziska Vielmuth
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Marie-Therès Wanuske
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Matthias Seifert
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Robert Pollmann
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany
| | - Rüdiger Eming
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany
| | - Jens Waschke
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, Germany
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10
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Vielmuth F, Walter E, Fuchs M, Radeva MY, Buechau F, Magin TM, Spindler V, Waschke J. Keratins Regulate p38MAPK-Dependent Desmoglein Binding Properties in Pemphigus. Front Immunol 2018; 9:528. [PMID: 29616033 PMCID: PMC5868517 DOI: 10.3389/fimmu.2018.00528] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/28/2018] [Indexed: 12/20/2022] Open
Abstract
Keratins are crucial for the anchorage of desmosomes. Severe alterations of keratin organization and detachment of filaments from the desmosomal plaque occur in the autoimmune dermatoses pemphigus vulgaris and pemphigus foliaceus (PF), which are mainly caused by autoantibodies against desmoglein (Dsg) 1 and 3. Keratin alterations are a structural hallmark in pemphigus pathogenesis and correlate with loss of intercellular adhesion. However, the significance for autoantibody-induced loss of intercellular adhesion is largely unknown. In wild-type (wt) murine keratinocytes, pemphigus autoantibodies induced keratin filament retraction. Under the same conditions, we used murine keratinocytes lacking all keratin filaments (KtyII k.o.) as a model system to dissect the role of keratins in pemphigus. KtyII k.o. cells show compromised intercellular adhesion without antibody (Ab) treatment, which was not impaired further by pathogenic pemphigus autoantibodies. Nevertheless, direct activation of p38MAPK via anisomycin further decreased intercellular adhesion indicating that cell cohesion was not completely abrogated in the absence of keratins. Direct inhibition of Dsg3, but not of Dsg1, interaction via pathogenic autoantibodies as revealed by atomic force microscopy was detectable in both cell lines demonstrating that keratins are not required for this phenomenon. However, PF-IgG shifted Dsg1-binding events from cell borders toward the free cell surface in wt cells. This led to a distribution pattern of Dsg1-binding events similar to KtyII k.o. cells under resting conditions. In keratin-deficient keratinocytes, PF-IgG impaired Dsg1-binding strength, which was not different from wt cells under resting conditions. In addition, pathogenic autoantibodies were capable of activating p38MAPK in both KtyII wt and k.o. cells, the latter of which already displayed robust p38MAPK activation under resting conditions. Since inhibition of p38MAPK blocked autoantibody-induced loss of intercellular adhesion in wt cells and restored baseline cell cohesion in keratin-deficient cells, we conclude that p38MAPK signaling is (i) critical for regulation of cell adhesion, (ii) regulated by keratins, and (iii) targets both keratin-dependent and -independent mechanisms.
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Affiliation(s)
- Franziska Vielmuth
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Elias Walter
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Michael Fuchs
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Mariya Y Radeva
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Fanny Buechau
- Division of Cell and Developmental Biology, Institute of Biology, Sächsische Inkubator für Klinische Translation (SIKT), University of Leipzig, Leipzig, Germany
| | - Thomas M Magin
- Division of Cell and Developmental Biology, Institute of Biology, Sächsische Inkubator für Klinische Translation (SIKT), University of Leipzig, Leipzig, Germany
| | - Volker Spindler
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jens Waschke
- Faculty of Medicine, Institute of Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
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11
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Abstract
IgG4 autoimmune diseases are characterized by the presence of antigen-specific autoantibodies of the IgG4 subclass and contain well-characterized diseases such as muscle-specific kinase myasthenia gravis, pemphigus, and thrombotic thrombocytopenic purpura. In recent years, several new diseases were identified, and by now 14 antigens targeted by IgG4 autoantibodies have been described. The IgG4 subclass is considered immunologically inert and functionally monovalent due to structural differences compared to other IgG subclasses. IgG4 usually arises after chronic exposure to antigen and competes with other antibody species, thus "blocking" their pathogenic effector mechanisms. Accordingly, in the context of IgG4 autoimmunity, the pathogenicity of IgG4 is associated with blocking of enzymatic activity or protein-protein interactions of the target antigen. Pathogenicity of IgG4 autoantibodies has not yet been systematically analyzed in IgG4 autoimmune diseases. Here, we establish a modified classification system based on Witebsky's postulates to determine IgG4 pathogenicity in IgG4 autoimmune diseases, review characteristics and pathogenic mechanisms of IgG4 in these disorders, and also investigate the contribution of other antibody entities to pathophysiology by additional mechanisms. As a result, three classes of IgG4 autoimmune diseases emerge: class I where IgG4 pathogenicity is validated by the use of subclass-specific autoantibodies in animal models and/or in vitro models of pathogenicity; class II where IgG4 pathogenicity is highly suspected but lack validation by the use of subclass specific antibodies in in vitro models of pathogenicity or animal models; and class III with insufficient data or a pathogenic mechanism associated with multivalent antigen binding. Five out of the 14 IgG4 antigens were validated as class I, five as class II, and four as class III. Antibodies of other IgG subclasses or immunoglobulin classes were present in several diseases and could contribute additional pathogenic mechanisms.
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Affiliation(s)
- Inga Koneczny
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
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12
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Spindler V, Waschke J. Pemphigus-A Disease of Desmosome Dysfunction Caused by Multiple Mechanisms. Front Immunol 2018; 9:136. [PMID: 29449846 PMCID: PMC5799217 DOI: 10.3389/fimmu.2018.00136] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/16/2018] [Indexed: 02/01/2023] Open
Abstract
Pemphigus is a severe autoimmune-blistering disease of the skin and mucous membranes caused by autoantibodies reducing desmosomal adhesion between epithelial cells. Autoantibodies against the desmosomal cadherins desmogleins (Dsgs) 1 and 3 as well as desmocollin 3 were shown to be pathogenic, whereas the role of other antibodies is unclear. Dsg3 interactions can be directly reduced by specific autoantibodies. Autoantibodies also alter the activity of signaling pathways, some of which regulate cell cohesion under baseline conditions and alter the turnover of desmosomal components. These pathways include Ca2+, p38MAPK, PKC, Src, EGFR/Erk, and several others. In this review, we delineate the mechanisms relevant for pemphigus pathogenesis based on the histology and the ultrastructure of patients’ lesions. We then dissect the mechanisms which can explain the ultrastructural hallmarks detectable in pemphigus patient skin. Finally, we reevaluate the concept that the spectrum of mechanisms, which induce desmosome dysfunction upon binding of pemphigus autoantibodies, finally defines the clinical phenotype.
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Affiliation(s)
- Volker Spindler
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Jens Waschke
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
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Egu DT, Walter E, Spindler V, Waschke J. Inhibition of p38MAPK signalling prevents epidermal blistering and alterations of desmosome structure induced by pemphigus autoantibodies in human epidermis. Br J Dermatol 2017; 177:1612-1618. [PMID: 28600798 DOI: 10.1111/bjd.15721] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND Pemphigus vulgaris (PV) is a skin blistering disease caused by autoantibodies targeting the desmosomal adhesion proteins desmoglein (Dsg) 3 and 1. The mechanisms underlying pemphigus skin blistering are not fully elucidated but p38 mitogen-activated protein kinase (p38MAPK) activation is one of the signalling events necessary for full loss of cell cohesion. However, it is unclear whether ultrastructural hallmarks of desmosome morphology as observed in patients' lesions are mediated by p38MAPK signalling. OBJECTIVES In this study, we tested the relevance of p38MAPK for blister formation and the ultrastructural changes induced by PV autoantibodies in human skin. METHODS Human skin samples were injected with IgG fractions of one patient suffering from mucocutaneous PV (mcPV-IgG), one from mucosal-dominant PV (mdPV-IgG) or AK23, a pathogenic monoclonal Dsg3 antibody derived from a pemphigus mouse model. Samples were processed for histological and electron microscopy analyses. RESULTS mcPV-IgG and AK23 but not mdPV-IgG reduced desmosome size, caused interdesmosomal widening and formation of split desmosomes, and altered keratin filament insertion. In contrast, full epidermal blister formation and lower desmosome number were evident in tissue samples exposed to mcPV-IgG only. Pharmacological inhibition of p38MAPK blunted the reduction of desmosome number and size, ameliorated interdesmosomal widening and loss of keratin insertion and prevented mcPV-IgG-induced blister formation. CONCLUSIONS Our data demonstrate that blistering can be prevented by inhibition of p38MAPK in the human epidermis. Moreover, typical morphological alterations induced by mcPV-IgG such as interdesmosomal widening and the reduction of desmosome size at least in part require p38MAPK signalling.
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Affiliation(s)
- D T Egu
- Department I, Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität (LMU), München, D-80336, Germany
| | - E Walter
- Department I, Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität (LMU), München, D-80336, Germany
| | - V Spindler
- Department I, Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität (LMU), München, D-80336, Germany
| | - J Waschke
- Department I, Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität (LMU), München, D-80336, Germany
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Walter E, Vielmuth F, Rotkopf L, Sárdy M, Horváth ON, Goebeler M, Schmidt E, Eming R, Hertl M, Spindler V, Waschke J. Different signaling patterns contribute to loss of keratinocyte cohesion dependent on autoantibody profile in pemphigus. Sci Rep 2017; 7:3579. [PMID: 28620161 PMCID: PMC5472593 DOI: 10.1038/s41598-017-03697-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 05/02/2017] [Indexed: 12/19/2022] Open
Abstract
Pemphigus is an autoimmune blistering skin disease caused primarily by autoantibodies against desmoglein (Dsg)1 and 3. Here, we characterized the mechanisms engaged by pemphigus IgG from patients with different clinical phenotypes and autoantibody profiles. All pemphigus vulgaris (PV) and pemphigus foliaceus (PF) IgG and AK23, a monoclonal mouse antibody against Dsg3, caused loss of cell cohesion, cytokeratin retraction and p38MAPK activation. Strong alterations in Dsg3 distribution were caused by mucosal (aDsg3 antibodies), mucocutaneous (aDsg1 + aDsg3) as well as atypical (aDsg3) PV-IgG. All PV-IgG fractions and AK23 compromised Dsg3 but not Dsg1 binding and enhanced Src activity. In contrast, rapid Ca2+ influx and Erk activation were induced by mucocutaneous PV-IgG and pemphigus foliaceus (PF) IgG (aDsg1) whereas cAMP was increased by mucosal and mucocutaneous PV-IgG only. Selective inhibition of p38MAPK, Src or PKC blocked loss of keratinocyte cohesion in response to all autoantibody fractions whereas Erk inhibition was protective against mucocutaneous PV-IgG and PF-IgG only. These results demonstrate that signaling patterns parallel the clinical phenotype as some mechanisms involved in loss of cell cohesion are caused by antibodies targeting Dsg3 whereas others correlate with autoantibodies against Dsg1. The concept of key desmosome regulators may explain observations from several experimental models of pemphigus.
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Affiliation(s)
- Elias Walter
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
| | - Franziska Vielmuth
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
| | - Lukas Rotkopf
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
| | - Miklós Sárdy
- Department of Dermatology and Allergology, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
| | - Orsolya N Horváth
- Department of Dermatology and Allergology, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
| | - Matthias Goebeler
- Department of Dermatology, Venerology and Allergology, University Hospital Würzburg, Würzburg, 97080, Germany
| | - Enno Schmidt
- Lübeck Institute of Experimental Dermatology (Lied), University of Lübeck, Lübeck, 23562, Germany
| | - Rüdiger Eming
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, 35037, Germany
| | - Michael Hertl
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, 35037, Germany
| | - Volker Spindler
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, 80336, Germany.
| | - Jens Waschke
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, 80336, Germany.
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Ludwig RJ, Vanhoorelbeke K, Leypoldt F, Kaya Z, Bieber K, McLachlan SM, Komorowski L, Luo J, Cabral-Marques O, Hammers CM, Lindstrom JM, Lamprecht P, Fischer A, Riemekasten G, Tersteeg C, Sondermann P, Rapoport B, Wandinger KP, Probst C, El Beidaq A, Schmidt E, Verkman A, Manz RA, Nimmerjahn F. Mechanisms of Autoantibody-Induced Pathology. Front Immunol 2017; 8:603. [PMID: 28620373 PMCID: PMC5449453 DOI: 10.3389/fimmu.2017.00603] [Citation(s) in RCA: 307] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/08/2017] [Indexed: 12/22/2022] Open
Abstract
Autoantibodies are frequently observed in healthy individuals. In a minority of these individuals, they lead to manifestation of autoimmune diseases, such as rheumatoid arthritis or Graves' disease. Overall, more than 2.5% of the population is affected by autoantibody-driven autoimmune disease. Pathways leading to autoantibody-induced pathology greatly differ among different diseases, and autoantibodies directed against the same antigen, depending on the targeted epitope, can have diverse effects. To foster knowledge in autoantibody-induced pathology and to encourage development of urgently needed novel therapeutic strategies, we here categorized autoantibodies according to their effects. According to our algorithm, autoantibodies can be classified into the following categories: (1) mimic receptor stimulation, (2) blocking of neural transmission, (3) induction of altered signaling, triggering uncontrolled (4) microthrombosis, (5) cell lysis, (6) neutrophil activation, and (7) induction of inflammation. These mechanisms in relation to disease, as well as principles of autoantibody generation and detection, are reviewed herein.
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Affiliation(s)
- Ralf J. Ludwig
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Karen Vanhoorelbeke
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Frank Leypoldt
- Neuroimmunology, Institute of Clinical Chemistry, University Hospital Schleswig-Holstein, Kiel, Germany
- Neuroimmunology, Institute of Clinical Chemistry, University Hospital Schleswig-Holstein, Lübeck, Germany
- Department of Neurology, University of Kiel, Kiel, Germany
| | - Ziya Kaya
- Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany
| | - Katja Bieber
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Sandra M. McLachlan
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA, United States
| | - Lars Komorowski
- Institute for Experimental Immunology, Affiliated to Euroimmun AG, Lübeck, Germany
| | - Jie Luo
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA, United States
| | | | | | - Jon M. Lindstrom
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA, United States
| | - Peter Lamprecht
- Department of Rheumatology, University of Lübeck, Lübeck, Germany
| | - Andrea Fischer
- Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany
| | | | - Claudia Tersteeg
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | | | - Basil Rapoport
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA, United States
| | - Klaus-Peter Wandinger
- Department of Neurology, Institute of Clinical Chemistry, University Medical-Centre Schleswig-Holstein, Lübeck, Germany
| | - Christian Probst
- Institute for Experimental Immunology, Affiliated to Euroimmun AG, Lübeck, Germany
| | - Asmaa El Beidaq
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Enno Schmidt
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Alan Verkman
- Department of Medicine, University of California, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, CA, United States
| | - Rudolf A. Manz
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Falk Nimmerjahn
- Department of Biology, Institute of Genetics, University of Erlangen-Nuremberg, Erlangen, Germany
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Non-pathogenic pemphigus foliaceus (PF) IgG acts synergistically with a directly pathogenic PF IgG to increase blistering by p38MAPK-dependent desmoglein 1 clustering. J Dermatol Sci 2016; 85:197-207. [PMID: 28024684 DOI: 10.1016/j.jdermsci.2016.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/13/2016] [Accepted: 12/12/2016] [Indexed: 11/22/2022]
Abstract
BACKGROUND Pemphigus foliaceus (PF) is an autoimmune blistering disease caused by autoantibodies (Abs) against desmoglein 1 (Dsg1). PF sera contain polyclonal Abs which are heterogeneous mixture of both pathogenic and non-pathogenic Abs, as shown by isolation of monoclonal Abs (mAbs). OBJECTIVE To investigate how pathogenic and non-pathogenic anti-Dsg1 Abs contribute to blister formation in PF. METHODS Using organ-cultured human skin, we compared the effect of a single pathogenic anti-Dsg1 IgG mAb, a single non-pathogenic anti-Dsg1 IgG mAb, and their mixture on blister formation as analyzed by histology, subcellular localization of IgG deposits and desmosomal proteins by confocal microscopy, and desmosomal structure by electron microscopy. In addition, we measured keratinocyte adhesion by an in vitro dissociation assay. RESULTS 24h after injection, a single pathogenic anti-Dsg1 IgG caused a subcorneal blister with IgG and Dsg1 localized linearly on the cell surface of keratinocytes. A single non-pathogenic anti-Dsg1 IgG bound linearly on the keratinocytes but did not induce blisters. A pathogenic and a non-pathogenic IgG mAb injected together caused an aberrant granular pattern of IgG and Dsg1 in the lower epidermis with blister formation in the superficial epidermis. Electron microscopy demonstrated that the mixture of mAbs shortened desmosomal lengths more than a single mAb in the basal and spinous layers. Furthermore, although Dsg1 clustering required both cross-linking of Dsg1 molecules by the non-pathogenic IgG plus a pathogenic antibody, the latter could be in the form of a monovalent single chain variable fragment, suggesting that loss of trans-interaction of Dsg1 is required for clustering. Finally, a p38MAPK inhibitor blocked Dsg1 clustering. When pathogenic strength was measured by the dissociation assay, a mixture of pathogenic and non-pathogenic IgG mAbs disrupted keratinocyte adhesion more than a single pathogenic mAb. This pathogenic effect was only partially suppressed by the p38MAPK inhibitor. CONCLUSION These findings indicate that a polyclonal mixture of anti-Dsg1 IgG antibodies enhances pathogenic activity for blister formation associated with p38MAPK-dependent Dsg1 clustering and that not only pathogenic antibodies but also non-pathogenic antibodies coordinately contribute to blister formation in PF.
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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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Hammers CM, Stanley JR. Mechanisms of Disease: Pemphigus and Bullous Pemphigoid. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2016; 11:175-97. [PMID: 26907530 DOI: 10.1146/annurev-pathol-012615-044313] [Citation(s) in RCA: 197] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pemphigus and bullous pemphigoid are autoantibody-mediated blistering skin diseases. In pemphigus, keratinocytes in epidermis and mucous membranes lose cell-cell adhesion, and in pemphigoid, the basal keratinocytes lose adhesion to the basement membrane. Pemphigus lesions are mediated directly by the autoantibodies, whereas the autoantibodies in pemphigoid fix complement and mediate inflammation. In both diseases, the autoantigens have been cloned and characterized; pemphigus antigens are desmogleins (cell adhesion molecules in desmosomes), and pemphigoid antigens are found in hemidesmosomes (which mediate adhesion to the basement membrane). This knowledge has enabled diagnostic testing for these diseases by enzyme-linked immunosorbent assays and dissection of various pathophysiological mechanisms, including direct inhibition of cell adhesion, antibody-induced internalization of antigen, and cell signaling. Understanding these mechanisms of disease has led to rational targeted therapeutic strategies.
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Affiliation(s)
- Christoph M Hammers
- Department of Dermatology, University of Pennsylvania, Philadelphia, Pennsylvania 19104; .,Department of Dermatology, University of Luebeck, D-23562 Luebeck, Germany;
| | - John R Stanley
- Department of Dermatology, University of Pennsylvania, Philadelphia, Pennsylvania 19104;
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Reijnders CMA, van Lier A, Roffel S, Kramer D, Scheper RJ, Gibbs S. Development of a Full-Thickness Human Skin Equivalent In Vitro Model Derived from TERT-Immortalized Keratinocytes and Fibroblasts. Tissue Eng Part A 2015; 21:2448-59. [PMID: 26135533 PMCID: PMC4554934 DOI: 10.1089/ten.tea.2015.0139] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Currently, human skin equivalents (HSEs) used for in vitro assays (e.g., for wound healing) make use of primary human skin cells. Limitations of primary keratinocytes and fibroblasts include availability of donor skin and donor variation. The use of physiologically relevant cell lines could solve these limitations. The aim was to develop a fully differentiated HSE constructed entirely from human skin cell lines, which could be applied for in vitro wound-healing assays. Skin equivalents were constructed from human TERT-immortalized keratinocytes and fibroblasts (TERT-HSE) and compared with native skin and primary HSEs. HSEs were characterized by hematoxylin–eosin and immunohistochemical stainings with markers for epidermal proliferation and differentiation, basement membrane (BM), fibroblasts, and the extracellular matrix (ECM). Ultrastructure was determined with electron microscopy. To test the functionality of the TERT-HSE, burn and cold injuries were applied, followed by immunohistochemical stainings, measurement of reepithelialization, and determination of secreted wound-healing mediators. The TERT-HSE was composed of a fully differentiated epidermis and a fibroblast-populated dermis comparable to native skin and primary HSE. The epidermis consisted of proliferating keratinocytes within the basal layer, followed by multiple spinous layers, a granular layer, and cornified layers. Within the TERT-HSE, the membrane junctions such as corneosomes, desmosomes, and hemidesmosomes were well developed as shown by ultrastructure pictures. Furthermore, the BM consisted of a lamina lucida and lamina densa comparable to native skin. The dermal matrix of the TERT-HSE was more similar to native skin than the primary construct, since collagen III, an ECM marker, was present in TERT-HSEs and absent in primary HSEs. After wounding, the TERT-HSE was able to reepithelialize and secrete inflammatory wound-healing mediators. In conclusion, the novel TERT-HSE, constructed entirely from human cell lines, provides an excellent opportunity to study in vitro skin biology and can also be used for drug targeting and testing new therapeutics, and ultimately, for incorporating into skin-on-a chip in the future.
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Affiliation(s)
| | - Amanda van Lier
- 1 Department of Dermatology, VU University Medical Centre , Amsterdam, The Netherlands
| | - Sanne Roffel
- 1 Department of Dermatology, VU University Medical Centre , Amsterdam, The Netherlands
| | - Duco Kramer
- 2 Department of Dermatology, University Medical Centre Groningen , Groningen, The Netherlands
| | - Rik J Scheper
- 3 Department of Pathology, VU University Medical Centre , Amsterdam, The Netherlands
| | - Susan Gibbs
- 1 Department of Dermatology, VU University Medical Centre , Amsterdam, The Netherlands .,4 Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam , Amsterdam, The Netherlands
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Abstract
Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement integrates adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, which occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on the way in which human diseases can inform our understanding of basic desmosome biology and in turn, the means by which fundamental advances in the cell biology of desmosomes might lead to new treatments for acquired diseases of the desmosome.
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Sokol E, Kramer D, Diercks GFH, Kuipers J, Jonkman MF, Pas HH, Giepmans BNG. Large-Scale Electron Microscopy Maps of Patient Skin and Mucosa Provide Insight into Pathogenesis of Blistering Diseases. J Invest Dermatol 2015; 135:1763-1770. [PMID: 25789704 DOI: 10.1038/jid.2015.109] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/23/2015] [Accepted: 02/03/2015] [Indexed: 12/24/2022]
Abstract
Large-scale electron microscopy ("nanotomy") allows straight forward ultrastructural examination of tissue, cells, organelles, and macromolecules in a single data set. Such data set equals thousands of conventional electron microscopy images and is freely accessible (www.nanotomy.org). The software allows zooming in and out of the image from total overview to nanometer scale resolution in a 'Google Earth' approach. We studied the life-threatening human autoimmune blistering disease pemphigus, using nanotomy. The pathomechanism of cell-cell separation (acantholysis) that underlies the blistering is poorly understood. Ultrastructural examination of pemphigus tissue revealed previously unreported findings: (i) the presence of double-membrane structures between cells in all pemphigus types; (ii) the absence of desmosomes around spontaneous blisters in pemphigus foliaceus (PF); (iii) lower level blistering in PF when force induced; and (iv) intercellular widening at non-acantholytic cell layers. Thus, nanotomy delivers open-source electron microscopic maps of patient tissue, which can be analyzed for additional anomalies from any computer by experts from different fields.
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Affiliation(s)
- Ena Sokol
- Department of Cell Biology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands; Department of Dermatology, Center for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Duco Kramer
- Department of Dermatology, Center for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Gilles F H Diercks
- Department of Dermatology, Center for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Jeroen Kuipers
- Department of Cell Biology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Marcel F Jonkman
- Department of Dermatology, Center for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Hendri H Pas
- Department of Dermatology, Center for Blistering Diseases, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Ben N G Giepmans
- Department of Cell Biology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
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22
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Broussard JA, Getsios S, Green KJ. Desmosome regulation and signaling in disease. Cell Tissue Res 2015; 360:501-12. [PMID: 25693896 DOI: 10.1007/s00441-015-2136-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 01/21/2015] [Indexed: 01/10/2023]
Abstract
Desmosomes are cell-cell adhesive organelles with a well-known role in forming strong intercellular adhesion during embryogenesis and in adult tissues subject to mechanical stress, such as the heart and skin. More recently, desmosome components have also emerged as cell signaling regulators. Loss of expression or interference with the function of desmosome molecules results in diseases of the heart and skin and contributes to cancer progression. However, the underlying molecular mechanisms that result in inherited and acquired disorders remain poorly understood. To address this question, researchers are directing their studies towards determining the functions that occur inside and outside of the junctions and the extent to which functions are adhesion-dependent or independent. This review focuses on recent discoveries that provide insights into the role of desmosomes and desmosome components in cell signaling and disease; wherever possible, we address molecular functions within and outside of the adhesive structure.
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Affiliation(s)
- Joshua A Broussard
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
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Dehner C, Rötzer V, Waschke J, Spindler V. A Desmoplakin Point Mutation with Enhanced Keratin Association Ameliorates Pemphigus Vulgaris Autoantibody-Mediated Loss of Cell Cohesion. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2528-36. [DOI: 10.1016/j.ajpath.2014.05.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 04/23/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
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Diercks GFH, Jonkman MF, Pas HH. Punctate pemphigus: an underreported direct immunofluorescence pattern. J Cutan Pathol 2014; 41:756-7. [PMID: 24975993 DOI: 10.1111/cup.12366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/07/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Gilles F H Diercks
- Centre for Blistering Diseases, Department of Dermatology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands; Department of Pathology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
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