1
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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: 9] [Impact Index Per Article: 9.0] [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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2
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Rübsam M, Püllen R, Tellkamp F, Bianco A, Peskoller M, Bloch W, Green KJ, Merkel R, Hoffmann B, Wickström SA, Niessen CM. Polarity signaling balances epithelial contractility and mechanical resistance. Sci Rep 2023; 13:7743. [PMID: 37173371 PMCID: PMC10182030 DOI: 10.1038/s41598-023-33485-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 04/13/2023] [Indexed: 05/15/2023] Open
Abstract
Epithelia maintain a functional barrier during tissue turnover while facing varying mechanical stress. This maintenance requires both dynamic cell rearrangements driven by actomyosin-linked intercellular adherens junctions and ability to adapt to and resist extrinsic mechanical forces enabled by keratin filament-linked desmosomes. How these two systems crosstalk to coordinate cellular movement and mechanical resilience is not known. Here we show that in stratifying epithelia the polarity protein aPKCλ controls the reorganization from stress fibers to cortical actomyosin during differentiation and upward movement of cells. Without aPKC, stress fibers are retained resulting in increased contractile prestress. This aberrant stress is counterbalanced by reorganization and bundling of keratins, thereby increasing mechanical resilience. Inhibiting contractility in aPKCλ-/- cells restores normal cortical keratin networks but also normalizes resilience. Consistently, increasing contractile stress is sufficient to induce keratin bundling and enhance resilience, mimicking aPKC loss. In conclusion, our data indicate that keratins sense the contractile stress state of stratified epithelia and balance increased contractility by mounting a protective response to maintain tissue integrity.
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Affiliation(s)
- Matthias Rübsam
- Department Cell Biology of the Skin, University Hospital Cologne, University of Cologne, Cologne, Germany.
- Cologne Excellence Cluster for Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University Hospital Cologne, University of Cologne, Cologne, Germany.
- Max Planck Institute for Biology of Ageing, 50931, Cologne, Germany.
| | - Robin Püllen
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-2: Mechanobiology, 52428, Jülich, Germany
| | - Frederik Tellkamp
- Department Cell Biology of the Skin, University Hospital Cologne, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster for Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Alessandra Bianco
- Department Cell Biology of the Skin, University Hospital Cologne, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster for Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Marc Peskoller
- Department Cell Biology of the Skin, University Hospital Cologne, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster for Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University of Cologne, Cologne, Germany
| | - Kathleen J Green
- Departments of Pathology and Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Rudolf Merkel
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-2: Mechanobiology, 52428, Jülich, Germany
| | - Bernd Hoffmann
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-2: Mechanobiology, 52428, Jülich, Germany
| | - Sara A Wickström
- Cologne Excellence Cluster for Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Max Planck Institute for Biology of Ageing, 50931, Cologne, Germany
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Carien M Niessen
- Department Cell Biology of the Skin, University Hospital Cologne, University of Cologne, Cologne, Germany.
- Cologne Excellence Cluster for Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University Hospital Cologne, University of Cologne, Cologne, Germany.
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3
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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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4
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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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5
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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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6
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Hiermaier M, Kugelmann D, Radeva MY, Didona D, Ghoreschi K, Farzan S, Hertl M, Waschke J. Pemphigus Foliaceus Autoantibodies Induce Redistribution Primarily of Extradesmosomal Desmoglein 1 in the Cell Membrane. Front Immunol 2022; 13:882116. [PMID: 35634274 PMCID: PMC9134081 DOI: 10.3389/fimmu.2022.882116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/20/2022] [Indexed: 11/23/2022] Open
Abstract
The autoimmune dermatosis pemphigus foliaceus (PF) is predominantly caused by IgG autoantibodies against the desmosomal cadherin desmoglein (Dsg) 1. The exact mechanisms that lead to the characteristic epidermal blistering are not yet fully understood. In the present study, we used a variety of biophysical methods to examine the fate of membrane-bound Dsg1 after incubation with PF patients’ IgG. Dispase-based dissociation assays confirmed that PF-IgG used for this study reduced intercellular adhesion in a manner dependent on phospholipase C (PLC)/Ca2+ and extracellular signal-regulated kinase (ERK) 1/2 signaling. Atomic force microscopy (AFM) revealed that Dsg1 binding on single molecule level paralleled effects on keratinocyte adhesion under the different conditions. Stimulated emission depletion (STED) super-resolution microscopy was used to investigate the localization of Dsg1 after PF-IgG incubation for 24 h. Under control conditions, Dsg1 was found to be in part co-localized with desmoplakin and thus inside of desmosomes as well as extra-desmosomal along the cell border. Incubation with PF-IgG reduced the extra-desmosomal Dsg1 fraction. In line with this, fluorescence recovery after photobleaching (FRAP) experiments demonstrated a strongly reduced mobility of Dsg1 in the cell membrane after PF-IgG treatment indicating remaining Dsg1 molecules were primarily located inside desmosomes. Mechanistically, experiments confirmed the involvement of PLC/Ca2+ since inhibition of PLC or 1,4,5-trisphosphate (IP3) receptor to reduce cytosolic Ca2+ reverted the effects of PF-IgG on Dsg1 intra-membrane mobility and localization. Taken together, our findings suggest that during the first 24 h PF-IgG induce redistribution predominantly of membrane-bound extradesmosomal Dsg1 in a PLC/Ca2+ dependent manner whereas Dsg1-containing desmosomes remain.
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Affiliation(s)
- Matthias Hiermaier
- Chair of Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, LMU Munich, München, Germany
| | - Daniela Kugelmann
- Chair of Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, LMU Munich, München, Germany
| | - Mariya Y Radeva
- Chair of Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, LMU Munich, München, Germany
| | - Dario Didona
- Department of Dermatology and Allergology, Philipps University, Marburg, Germany
| | - Kamran Ghoreschi
- Department of Dermatology, Venereology and Allergology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Department of Dermatology, University Medical Center, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Solimani Farzan
- Department of Dermatology, Venereology and Allergology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Hertl
- Department of Dermatology and Allergology, Philipps University, Marburg, Germany
| | - Jens Waschke
- Chair of Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, LMU Munich, München, Germany
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7
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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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8
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Zimmer SE, Takeichi T, Conway DE, Kubo A, Suga Y, Akiyama M, Kowalczyk AP. Differential Pathomechanisms of Desmoglein 1 Transmembrane Domain Mutations in Skin Disease. J Invest Dermatol 2022; 142:323-332.e8. [PMID: 34352264 PMCID: PMC9109890 DOI: 10.1016/j.jid.2021.07.154] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 06/25/2021] [Accepted: 07/12/2021] [Indexed: 02/03/2023]
Abstract
Dominant and recessive mutations in the desmosomal cadherin, desmoglein (DSG) 1, cause the skin diseases palmoplantar keratoderma (PPK) and severe dermatitis, multiple allergies, and metabolic wasting (SAM) syndrome, respectively. In this study, we compare two dominant missense mutations in the DSG1 transmembrane domain (TMD), G557R and G562R, causing PPK (DSG1PPK-TMD) and SAM syndrome (DSG1SAM-TMD), respectively, to determine the differing pathomechanisms of these mutants. Expressing the DSG1TMD mutants in a DSG-null background, we use cellular and biochemical assays to reveal the differences in the mechanistic behavior of each mutant. Super-resolution microscopy and functional assays showed a failure by both mutants to assemble desmosomes due to reduced membrane trafficking and lipid raft targeting. DSG1SAM-TMD maintained normal expression levels and turnover relative to wildtype DSG1, but DSG1PPK-TMD lacked stability, leading to increased turnover through lysosomal and proteasomal pathways and reduced expression levels. These results differentiate the underlying pathomechanisms of these disorders, suggesting that DSG1SAM-TMD acts dominant negatively, whereas DSG1PPK-TMD is a loss-of-function mutation causing the milder PPK disease phenotype. These mutants portray the importance of the DSG TMD in desmosome function and suggest that a greater understanding of the desmosomal cadherin TMDs will further our understanding of the role that desmosomes play in epidermal pathophysiology.
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Affiliation(s)
- Stephanie E. Zimmer
- Department of Dermatology, Penn State College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA,Biochemistry, Cell and Developmental Biology Graduate Program, Emory School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Takuya Takeichi
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Daniel E. Conway
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Akiharu Kubo
- Division of Dermatology, Department of Internal Related, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yasushi Suga
- Department of Dermatology, Juntendo University Urayasu Hospital, Urayasu, Japan
| | - Masashi Akiyama
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Andrew P. Kowalczyk
- Department of Dermatology, Penn State College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA,Department of Cellular & Molecular Physiology, Penn State College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA
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9
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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: 6] [Impact Index Per Article: 2.0] [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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10
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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: 14] [Impact Index Per Article: 4.7] [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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11
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Igarashi M, Honda A, Kawasaki A, Nozumi M. Neuronal Signaling Involved in Neuronal Polarization and Growth: Lipid Rafts and Phosphorylation. Front Mol Neurosci 2020; 13:150. [PMID: 32922262 PMCID: PMC7456915 DOI: 10.3389/fnmol.2020.00150] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/16/2020] [Indexed: 12/17/2022] Open
Abstract
Neuronal polarization and growth are developmental processes that occur during neuronal cell differentiation. The molecular signaling mechanisms involved in these events in in vivo mammalian brain remain unclear. Also, cellular events of the neuronal polarization process within a given neuron are thought to be constituted of many independent intracellular signal transduction pathways (the "tug-of-war" model). However, in vivo results suggest that such pathways should be cooperative with one another among a given group of neurons in a region of the brain. Lipid rafts, specific membrane domains with low fluidity, are candidates for the hotspots of such intracellular signaling. Among the signals reported to be involved in polarization, a number are thought to be present or translocated to the lipid rafts in response to extracellular signals. As part of our analysis, we discuss how such novel molecular mechanisms are combined for effective regulation of neuronal polarization and growth, focusing on the significance of the lipid rafts, including results based on recently introduced methods.
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Affiliation(s)
- Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Atsuko Honda
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Motohiro Nozumi
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
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12
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Hammers CM, Stanley JR. Recent Advances in Understanding Pemphigus and Bullous Pemphigoid. J Invest Dermatol 2020; 140:733-741. [DOI: 10.1016/j.jid.2019.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/29/2019] [Accepted: 11/01/2019] [Indexed: 12/11/2022]
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13
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Egu DT, Kugelmann D, Waschke J. Role of PKC and ERK Signaling in Epidermal Blistering and Desmosome Regulation in Pemphigus. Front Immunol 2019; 10:2883. [PMID: 31867019 PMCID: PMC6910072 DOI: 10.3389/fimmu.2019.02883] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/25/2019] [Indexed: 01/27/2023] Open
Abstract
Desmosomes reinforce cohesion of epithelial cells at the interface between adjacent cells. They include the cadherin-type adhesion molecules desmoglein 1 (Dsg1) and Dsg3. Pemphigus vulgaris (PV) is an autoimmune disease in which circulating autoantibodies (PV-IgG) targeting Dsg1 and 3 cause characteristic epidermal blister formation. It has been shown that PV-IgG binding induced activation of kinases such as ERK and PKC, and inhibition of these signaling pathways prevented loss of cell cohesion in cell cultures. However, the role of Erk and PKC in blister formation and regulation of desmosome ultrastructure in human skin are unknown. Accordingly, we assessed the role of PKC and ERK signaling pathways in blister formation and regulation of desmosome ultrastructure in human epidermis. Here we performed electron microscopy analyses using human skin explants injected with PV-IgG together with inhibitors for PKC or ERK signaling. Inhibition of PKC was not effective to prevent suprabasal blister formation or ultrastructural alterations of desmosomes. In contrast, inhibition of ERK signaling significantly ameliorated blister formation and decrease in the number of desmosomes whereas shortening and splitting of desmosomes and keratin filament insertion were not different from samples treated with PV-IgG alone. However, apical desmosomes between basal and suprabasal cells remained unaltered when ERK signaling was inhibited. Therefore, our results show that inhibition of ERK but not PKC signaling appears to be effective to ameliorate blistering and alterations of desmosome ultrastructure triggered by PV-IgG in human skin.
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Affiliation(s)
- Desalegn Tadesse Egu
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, LMU Munich, Munich, Germany
| | - Daniela Kugelmann
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, LMU Munich, Munich, Germany
| | - Jens Waschke
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, LMU Munich, Munich, Germany
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14
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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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15
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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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16
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Cho A, Caldara AL, Ran NA, Menne Z, Kauffman RC, Affer M, Llovet A, Norwood C, Scanlan A, Mantus G, Bradley B, Zimmer S, Schmidt T, Hertl M, Payne AS, Feldman R, Kowalczyk AP, Wrammert J. Single-Cell Analysis Suggests that Ongoing Affinity Maturation Drives the Emergence of Pemphigus Vulgaris Autoimmune Disease. Cell Rep 2019; 28:909-922.e6. [PMID: 31340153 PMCID: PMC6684256 DOI: 10.1016/j.celrep.2019.06.066] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 05/22/2019] [Accepted: 06/18/2019] [Indexed: 11/29/2022] Open
Abstract
Pemphigus vulgaris (PV) is an autoimmune disease characterized by blistering sores on skin and mucosal membranes, caused by autoantibodies primarily targeting the cellular adhesion protein, desmoglein-3 (Dsg3). To better understand how Dsg3-specific autoantibodies develop and cause disease in humans, we performed a cross-sectional study of PV patients before and after treatment to track relevant cellular responses underlying disease pathogenesis, and we provide an in-depth analysis of two patients by generating a panel of mAbs from single Dsg3-specific memory B cells (MBCs). Additionally, we analyzed a paired sample from one patient collected 15-months prior to disease diagnosis. We find that Dsg3-specific MBCs have an activated phenotype and show signs of ongoing affinity maturation and clonal selection. Monoclonal antibodies (mAbs) with pathogenic activity primarily target epitopes in the extracellular domains EC1 and EC2 of Dsg3, though they can also bind to the EC4 domain. Combining antibodies targeting different epitopes synergistically enhances in vitro pathogenicity.
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Affiliation(s)
- Alice Cho
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Amber L Caldara
- Department of Cell Biology, Emory University, Atlanta, GA, USA; Department of Dermatology, Emory University School of Medicine, Atlanta, GA, USA
| | - Nina A Ran
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Zach Menne
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Robert C Kauffman
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Maurizio Affer
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Alexandra Llovet
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Carson Norwood
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Aaron Scanlan
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Grace Mantus
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Bridget Bradley
- Department of Dermatology, Emory University School of Medicine, Atlanta, GA, USA
| | - Stephanie Zimmer
- Department of Cell Biology, Emory University, Atlanta, GA, USA; Department of Dermatology, Emory University School of Medicine, Atlanta, GA, USA
| | - Thomas Schmidt
- Department of Dermatology and Allergology, Philipps-University, Marburg, Germany
| | - Michael Hertl
- Department of Dermatology and Allergology, Philipps-University, Marburg, Germany
| | - Aimee S Payne
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ron Feldman
- Department of Dermatology, Emory University School of Medicine, Atlanta, GA, USA
| | - Andrew P Kowalczyk
- Department of Cell Biology, Emory University, Atlanta, GA, USA; Department of Dermatology, Emory University School of Medicine, Atlanta, GA, USA
| | - Jens Wrammert
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA.
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17
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Gornowicz-Porowska J, Bowszyc-Dmochowska M, Raptis-Bolwach M, Seraszek-Jaros A, Kaczmarek E, Dmochowski M. Blue light-emitting diode technology-operated microscopy is preferable to both short arc mercury lamp-operated microscopy and laser scanning confocal microscopy for direct immunofluorescence images evaluation in routinely diagnosing subepidermal autoimmune blistering diseases. Microsc Res Tech 2019; 82:1735-1740. [PMID: 31290199 DOI: 10.1002/jemt.23339] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 01/04/2019] [Accepted: 06/25/2019] [Indexed: 11/07/2022]
Abstract
Direct immunofluorescence (DIF) microscopy still is the gold standard in diagnosing and differentiating subepidermal autoimmune blistering diseases (SABDs) from other bullous diseases. New optical systems were developed that aim to facilitate DIF images evaluation. The aim of the study was to evaluate the usefulness of three fluorescence microscopy systems with different light source for routine diagnostics of SABDs with DIF. In total, perilesional tissue samples for DIF from 34 SABD patients were examined under the three commercial microscopy systems (short arc mercury lamp-operated microscopy-MLM, blue light-emitting diode technology-operated microscopy-bLED and laser scanning confocal microscopy-LSCM) for the detection and pattern analysis of IgA, IgG, IgG1, IgG4, C3 immunoreactants along the dermal-epidermal junction (DEJ) by three independent observers simultaneously. MLM, bLED, and LSCM provided comparable quality of disease-characterizing immunoreactants imaging (number of immunoreactant types detected and patterns of their deposition along DEJ were the same) but screening of slides was quicker using bLED than both LSCM and MLM, as statistical analysis indicated. It is concluded that bLED is an efficient and preferable system for routinely diagnosing SABDs cost-effectively. RESEARCH HIGHLIGHTS: New optical systems were developed that aim to facilitate direct immunofluorescence evaluation. Here, we evaluate the usefulness of three fluorescence microscopy systems with different light source for routine diagnostics concluding that that bLED is an efficient and preferable system.
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Affiliation(s)
- Justyna Gornowicz-Porowska
- Department of Medicinal and Cosmetic Natural Products, Poznan University of Medical Sciences, Poznan, Poland.,Autoimmune Blistering Dermatoses Section, Department of Dermatology, Poznan University of Medical Sciences, Poznan, Poland
| | - Monika Bowszyc-Dmochowska
- Cutaneous Histopathology and Immunopathology Section, Department of Dermatology, Poznan University of Medical Sciences, Poznan, Poland
| | - Maria Raptis-Bolwach
- Cutaneous Histopathology and Immunopathology Section, Department of Dermatology, Poznan University of Medical Sciences, Poznan, Poland
| | - Agnieszka Seraszek-Jaros
- Department of Bioinformatics and Computational Biology, Poznan University of Medical Sciences, Poznan, Poland
| | - Elżbieta Kaczmarek
- Department of Bioinformatics and Computational Biology, Poznan University of Medical Sciences, Poznan, Poland
| | - Marian Dmochowski
- Autoimmune Blistering Dermatoses Section, Department of Dermatology, Poznan University of Medical Sciences, Poznan, Poland
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18
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Pullman JM. New Views of the Glomerulus: Advanced Microscopy for Advanced Diagnosis. Front Med (Lausanne) 2019; 6:37. [PMID: 30899761 PMCID: PMC6416220 DOI: 10.3389/fmed.2019.00037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 02/08/2019] [Indexed: 12/11/2022] Open
Abstract
New technologies are ready to revolutionize glomerular imaging and significantly improve or replace immunofluorescence and electron microscopy, which have driven research and diagnosis of glomerular diseases for over 50 years. Advanced forms of transmission and scanning electron microscopy have revealed the detailed spatial relationships of the glomerular basement membrane, podocytes, and endothelial cells. These may be overshadowed by super resolution microscopy (SRM), which combines the advantages of immunofluorescence and electron microscopy, offers high resolution identification of specific molecules, and images large, physiologically relevant volumes of the glomerulus. Rapidity, ease of use and low cost with some types of SRM make them potentially suitable for routine diagnosis. SRM visualizes structures below the classical diffraction limit of conventional light microscopy by adding a time variable to either the illumination of the specimen, or to the fluorescence signal emitted by it. Ensemble techniques vary illumination and include Structured Illumination Microscopy (SIM) and Stimulation Emission Depletion Microscopy (STED). Single molecule localization techniques vary the light emission by fluorescence labels in the specimen, and include Photoactivated Localization Microscopy (PALM) and Stochastic Optical Reconstruction Microscopy (STORM). Technologies such as expansion microscopy and genetic labeling can also create effective super resolution imaging by non-optical, specialized preparation techniques. All technologies require dark field fluorescence and some require computer image analysis and reconstruction. Replicating successful application in other areas of biology, SIM, STED, and STORM have visualized normal and nephrotic disease podocytes, and have confirmed their appearances to be similar to those seen by electron microscopy, but with added new information on cell configuration and protein localization. STORM has also localized podocyte cytoskeleton and adhesion proteins, and glomerular basement membrane proteins at a resolution never before possible. These pioneering efforts show the promise of super resolution microscopy, and lay the groundwork for future study and new diagnostic tools for glomerular diseases.
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Affiliation(s)
- James M Pullman
- Division of Anatomic Pathology, Department of Pathology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY, United States
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19
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Neagu AN. Proteome Imaging: From Classic to Modern Mass Spectrometry-Based Molecular Histology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1140:55-98. [PMID: 31347042 DOI: 10.1007/978-3-030-15950-4_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In order to overcome the limitations of classic imaging in Histology during the actually era of multiomics, the multi-color "molecular microscope" by its emerging "molecular pictures" offers quantitative and spatial information about thousands of molecular profiles without labeling of potential targets. Healthy and diseased human tissues, as well as those of diverse invertebrate and vertebrate animal models, including genetically engineered species and cultured cells, can be easily analyzed by histology-directed MALDI imaging mass spectrometry. The aims of this review are to discuss a range of proteomic information emerging from MALDI mass spectrometry imaging comparative to classic histology, histochemistry and immunohistochemistry, with applications in biology and medicine, concerning the detection and distribution of structural proteins and biological active molecules, such as antimicrobial peptides and proteins, allergens, neurotransmitters and hormones, enzymes, growth factors, toxins and others. The molecular imaging is very well suited for discovery and validation of candidate protein biomarkers in neuroproteomics, oncoproteomics, aging and age-related diseases, parasitoproteomics, forensic, and ecotoxicology. Additionally, in situ proteome imaging may help to elucidate the physiological and pathological mechanisms involved in developmental biology, reproductive research, amyloidogenesis, tumorigenesis, wound healing, neural network regeneration, matrix mineralization, apoptosis and oxidative stress, pain tolerance, cell cycle and transformation under oncogenic stress, tumor heterogeneity, behavior and aggressiveness, drugs bioaccumulation and biotransformation, organism's reaction against environmental penetrating xenobiotics, immune signaling, assessment of integrity and functionality of tissue barriers, behavioral biology, and molecular origins of diseases. MALDI MSI is certainly a valuable tool for personalized medicine and "Eco-Evo-Devo" integrative biology in the current context of global environmental challenges.
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Affiliation(s)
- Anca-Narcisa Neagu
- Laboratory of Animal Histology, Faculty of Biology, "Alexandru Ioan Cuza" University of Iasi, Iasi, Romania.
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20
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Abstract
Pemphigus and pemphigoid are characterized as autoimmune blistering diseases in which immunoglobulin G autoantibodies cause blisters and erosions of the skin or mucosa or both. Recently, understanding of the pathophysiology of pemphigus and pemphigoid has been furthered by genetic analyses, characterization of autoantibodies and autoreactive B cells, and elucidation of cell–cell adhesion between keratinocytes. For the management of pemphigus and pemphigoid, the administration of systemic corticosteroids still represents the standard treatment strategy; however, evidence of the efficacy of therapies not involving corticosteroids, such as those employing anti-CD20 antibodies, is increasing. The goal should be to develop antigen-specific immune suppression-based treatments.
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Affiliation(s)
- Jun Yamagami
- Department of Dermatology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
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21
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Shafraz O, Rübsam M, Stahley SN, Caldara AL, Kowalczyk AP, Niessen CM, Sivasankar S. E-cadherin binds to desmoglein to facilitate desmosome assembly. eLife 2018; 7:37629. [PMID: 29999492 PMCID: PMC6066328 DOI: 10.7554/elife.37629] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/10/2018] [Indexed: 02/04/2023] Open
Abstract
Desmosomes are adhesive junctions composed of two desmosomal cadherins: desmocollin (Dsc) and desmoglein (Dsg). Previous studies demonstrate that E-cadherin (Ecad), an adhesive protein that interacts in both trans (between opposing cells) and cis (on the same cell surface) conformations, facilitates desmosome assembly via an unknown mechanism. Here we use structure-function analysis to resolve the mechanistic roles of Ecad in desmosome formation. Using AFM force measurements, we demonstrate that Ecad interacts with isoform 2 of Dsg via a conserved Leu-175 on the Ecad cis binding interface. Super-resolution imaging reveals that Ecad is enriched in nascent desmosomes, supporting a role for Ecad in early desmosome assembly. Finally, confocal imaging demonstrates that desmosome assembly is initiated at sites of Ecad mediated adhesion, and that Ecad-L175 is required for efficient Dsg2 and desmoplakin recruitment to intercellular contacts. We propose that Ecad trans interactions at nascent cell-cell contacts initiate the recruitment of Dsg through direct cis interactions with Ecad which facilitates desmosome assembly.
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Affiliation(s)
- Omer Shafraz
- Department of Physics and Astronomy, Iowa State University, Ames, United States
| | - Matthias Rübsam
- Department of Dermatology, Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sara N Stahley
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Amber L Caldara
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Andrew P Kowalczyk
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Carien M Niessen
- Department of Dermatology, Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sanjeevi Sivasankar
- Department of Physics and Astronomy, Iowa State University, Ames, United States
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22
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Vielmuth F, Spindler V, Waschke J. Atomic Force Microscopy Provides New Mechanistic Insights into the Pathogenesis of Pemphigus. Front Immunol 2018; 9:485. [PMID: 29643851 PMCID: PMC5883869 DOI: 10.3389/fimmu.2018.00485] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/23/2018] [Indexed: 12/19/2022] Open
Abstract
Autoantibodies binding to the extracellular domains of desmoglein (Dsg) 3 and 1 are critical in the pathogenesis of pemphigus by mechanisms leading to impaired function of desmosomes and blister formation in the epidermis and mucous membranes. Desmosomes are highly organized protein complexes which provide strong intercellular adhesion. Desmosomal cadherins such as Dsgs, proteins of the cadherin superfamily which interact via their extracellular domains in Ca2+-dependent manner, are the transmembrane adhesion molecules clustered within desmosomes. Investigations on pemphigus cover a wide range of experimental approaches including biophysical methods. Especially atomic force microscopy (AFM) has recently been applied increasingly because it allows the analysis of native materials such as cultured cells and tissues under near-physiological conditions. AFM provides information about the mechanical properties of the sample together with detailed interaction analyses of adhesion molecules. With AFM, it was recently demonstrated that autoantibodies directly inhibit Dsg interactions on the surface of living keratinocytes, a phenomenon which has long been considered the main mechanism causing loss of cell cohesion in pemphigus. In addition, AFM allows to study how signaling pathways altered in pemphigus control binding properties of Dsgs. More general, AFM and other biophysical studies recently revealed the importance of keratin filaments for regulation of Dsg binding and keratinocyte mechanical properties. In this mini-review, we reevaluate AFM studies in pemphigus and keratinocyte research, recapitulate what is known about the interaction mechanisms of desmosomal cadherins and discuss the advantages and limitations of AFM in these regards.
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Affiliation(s)
| | | | - Jens Waschke
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
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23
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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: 18] [Impact Index Per Article: 3.0] [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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24
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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: 61] [Impact Index Per Article: 10.2] [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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25
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Spindler V, Eming R, Schmidt E, Amagai M, Grando S, Jonkman MF, Kowalczyk AP, Müller EJ, Payne AS, Pincelli C, Sinha AA, Sprecher E, Zillikens D, Hertl M, Waschke J. Mechanisms Causing Loss of Keratinocyte Cohesion in Pemphigus. J Invest Dermatol 2017; 138:32-37. [PMID: 29037765 DOI: 10.1016/j.jid.2017.06.022] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 11/28/2022]
Abstract
The autoimmune blistering skin disease pemphigus is caused by IgG autoantibodies against desmosomal cadherins, but the precise mechanisms are in part a matter of controversial discussions. This review focuses on the currently existing models of the disease and highlights the relevance of desmoglein-specific versus nondesmoglein autoantibodies, the contribution of nonautoantibody factors, and the mechanisms leading to cell dissociation and blister formation in response to autoantibody binding. As the review brings together the majority of laboratories currently working on pemphigus pathogenesis, it aims to serve as a solid basis for further investigations for the entire field.
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Affiliation(s)
- Volker Spindler
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität, Munich, Germany.
| | - Rüdiger Eming
- Department of Dermatology, University of Marburg, Marburg, Germany
| | - Enno Schmidt
- Department of Dermatology, University of Lübeck, Lübeck, Germany; Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Masayuki Amagai
- Department of Dermatology, Keio University School of Medicine, Tokyo, Japan
| | - Sergei Grando
- Institute for Immunology and Departments of Dermatology and Biological Chemistry, University of California, Irvine, California, USA
| | - Marcel F Jonkman
- Department of Dermatology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Andrew P Kowalczyk
- Departments of Cell Biology and Dermatology, Emory University, Atlanta, Georgia, USA
| | - Eliane J Müller
- Vetsuisse Faculty, Molecular Dermatology and Stem Cell Research, Institute of Animal Pathology, Bern, Switzerland; Vetsuisse Faculty, DermFocus, Bern, Switzerland; Department of Dermatology, University Hospital of Bern, Bern, Switzerland
| | - Aimee S Payne
- Department of Dermatology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Carlo Pincelli
- Laboratory of Cutaneous Biology, University of Modena and Reggio Emilia, Modena, Italy
| | - Animesh A Sinha
- Department of Dermatology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Eli Sprecher
- Department of Dermatology, Tel Aviv Medical Center, Tel Aviv, Israel
| | - Detlef Zillikens
- Department of Dermatology, University of Lübeck, Lübeck, Germany
| | - Michael Hertl
- Department of Dermatology, University of Marburg, Marburg, Germany
| | - Jens Waschke
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität, Munich, Germany.
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26
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Abstract
Pemphigus is a group of IgG-mediated autoimmune diseases of stratified squamous epithelia, such as the skin and oral mucosa, in which acantholysis (the loss of cell adhesion) causes blisters and erosions. Pemphigus has three major subtypes: pemphigus vulgaris, pemphigus foliaceus and paraneoplastic pemphigus. IgG autoantibodies are characteristically raised against desmoglein 1 and desmoglein 3, which are cell-cell adhesion molecules found in desmosomes. The sites of blister formation can be physiologically explained by the anti-desmoglein autoantibody profile and tissue-specific expression pattern of desmoglein isoforms. The pathophysiological roles of T cells and B cells have been characterized in mouse models of pemphigus and patients, revealing insights into the mechanisms of autoimmunity. Diagnosis is based on clinical manifestations and confirmed with histological and immunochemical testing. The current first-line treatment is systemic corticosteroids and adjuvant therapies, including immunosuppressive agents, intravenous immunoglobulin and plasmapheresis. Rituximab, a monoclonal antibody against CD20+ B cells, is a promising therapeutic option that may soon become first-line therapy. Pemphigus is one of the best-characterized human autoimmune diseases and provides an ideal paradigm for both basic and clinical research, especially towards the development of antigen-specific immune suppression treatments for autoimmune diseases.
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27
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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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28
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Abstract
Super resolution imaging is becoming an increasingly important tool in the arsenal of methods available to cell biologists. In recognition of its potential, the Nobel Prize for chemistry was awarded to three investigators involved in the development of super resolution imaging methods in 2014. The availability of commercial instruments for super resolution imaging has further spurred the development of new methods and reagents designed to take advantage of super resolution techniques. Super resolution offers the advantages traditionally associated with light microscopy, including the use of gentle fixation and specimen preparation methods, the ability to visualize multiple elements within a single specimen, and the potential to visualize dynamic changes in living specimens over time. However, imaging of living cells over time is difficult and super resolution imaging is computationally demanding. In this review, we discuss the advantages/disadvantages of different super resolution systems for imaging fixed live specimens, with particular regard to cytoskeleton structures.
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Affiliation(s)
- Eric A Shelden
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Zachary T Colburn
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Jonathan C R Jones
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
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