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Bchetnia M, Powell J, McCuaig C, Boucher-Lafleur AM, Morin C, Dupéré A, Laprise C. Pathological Mechanisms Involved in Epidermolysis Bullosa Simplex: Current Knowledge and Therapeutic Perspectives. Int J Mol Sci 2024; 25:9495. [PMID: 39273442 PMCID: PMC11394917 DOI: 10.3390/ijms25179495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Revised: 08/22/2024] [Accepted: 08/29/2024] [Indexed: 09/15/2024] Open
Abstract
Epidermolysis bullosa (EB) is a clinically and genetically heterogeneous group of mechanobullous diseases characterized by non-scarring blisters and erosions on the skin and mucous membranes upon mechanical trauma. The simplex form (EBS) is characterized by recurrent blister formation within the basal layer of the epidermis. It most often results from dominant mutations in the genes coding for keratin (K) 5 or 14 proteins (KRT5 and KRT14). A disruptive mutation in KRT5 or KRT14 will not only structurally impair the cytoskeleton, but it will also activate a cascade of biochemical mechanisms contributing to EBS. Skin lesions are painful and disfiguring and have a significant impact on life quality. Several gene expression studies were accomplished on mouse model and human keratinocytes to define the gene expression signature of EBS. Several key genes associated with EBS were identified as specific immunological mediators, keratins, and cell junction components. These data deepened the understanding of the EBS pathophysiology and revealed important functional biological processes, particularly inflammation. This review emphasizes the three EBS subtypes caused by dominant mutations on either KRT5 or KRT14 (localized, intermediate, and severe). It aims to summarize current knowledge about the EBS expression profiling pattern and predicted molecular mechanisms involved and to outline progress in therapy.
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Affiliation(s)
- Mbarka Bchetnia
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Saguenay, QC G7H 2B1, Canada
- Centre Intersectoriel en Santé Durable, Saguenay, QC G7H 2B1, Canada
| | - Julie Powell
- CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada
| | | | - Anne-Marie Boucher-Lafleur
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Saguenay, QC G7H 2B1, Canada
- Centre Intersectoriel en Santé Durable, Saguenay, QC G7H 2B1, Canada
| | - Charles Morin
- Centre Intégré Universitaire de Santé et de Services Sociaux du Saguenay-Lac-Saint-Jean, Hôpital Universitaire de Chicoutimi, Saguenay, QC G7H 7K9, Canada
| | - Audrey Dupéré
- Centre Intégré Universitaire de Santé et de Services Sociaux du Saguenay-Lac-Saint-Jean, Hôpital Universitaire de Chicoutimi, Saguenay, QC G7H 7K9, Canada
| | - Catherine Laprise
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Saguenay, QC G7H 2B1, Canada
- Centre Intersectoriel en Santé Durable, Saguenay, QC G7H 2B1, Canada
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2
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Ilomäki MA, Polari L, Stenvall CGA, Tayyab M, Kähärä K, Ridge KM, Toivola DM. Defining a timeline of colon pathologies after keratin 8 loss: rapid crypt elongation and diarrhea are followed by epithelial erosion and cell exfoliation. Am J Physiol Gastrointest Liver Physiol 2024; 326:G67-G77. [PMID: 37962942 PMCID: PMC11208023 DOI: 10.1152/ajpgi.00140.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/27/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023]
Abstract
Keratins are epithelial intermediate filament proteins that play a crucial role in cellular stress protection, with K8 being the most abundant in the colon. The intestinal epithelial-specific K8-deficient mouse model (K8flox/flox;Villin-Cre) exhibits characteristics of inflammatory bowel disease, including diarrhea, crypt erosion, hyperproliferation, and decreased barrier function. Nevertheless, the order in which these events occur and whether they are a direct cause of K8 loss or a consequence of one event inducing another remains unexplored. Increased knowledge about early events in the disruption of colon epithelial integrity would help to understand the early pathology of inflammatory and functional colon disorders and develop preclinical models and diagnostics of colonic diseases. Here, we aimed to characterize the order of physiological events after Krt8 loss by utilizing K8flox/flox;Villin-CreERt2 mice with tamoxifen-inducible Krt8 deletion in intestinal epithelial cells, and assess stool analysis as a noninvasive method to monitor real-time gene expression changes following Krt8 loss. K8 protein was significantly decreased within a day after induction, followed by its binding partners, K18 and K19 from day 4 onward. The sequential colonic K8 downregulation in adult mice leads to immediate diarrhea and crypt elongation with activation of proliferation signaling, followed by crypt loss and increased neutrophil activity within 6-8 days, highlighting impaired water balance and crypt elongation as the earliest colonic changes upon Krt8 loss. Furthermore, epithelial gene expression patterns were comparable between colon tissue and stool samples, demonstrating the feasibility of noninvasive monitoring of gut epithelia in preclinical research utilizing Cre-LoxP-based intestinal disease models.NEW & NOTEWORTHY Understanding the order in which physiological and molecular events occur helps to recognize the onset of diseases and improve their preclinical models. We utilized Cre-Lox-based inducible keratin 8 deletion in mouse intestinal epithelium to characterize the earliest events after keratin 8 loss leading to colitis. These include diarrhea and crypt elongation, followed by erosion and neutrophil activity. Our results also support noninvasive methodology for monitoring colon diseases in preclinical models.
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Affiliation(s)
- Maria A Ilomäki
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
| | - Lauri Polari
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
| | - Carl-Gustaf A Stenvall
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
| | - Mina Tayyab
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
| | - Kirah Kähärä
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Karen M Ridge
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois, United States
| | - Diana M Toivola
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
- Turku Center for Disease Modeling, University of Turku, Turku, Finland
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3
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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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4
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Mohamad J, Sarig O, Beattie P, Malovitski K, Assaf S, O'Toole E, Schwartz J, Evans H, Samuelov L, Sprecher E. A unique skin phenotype resulting from a large heterozygous deletion spanning six keratin genes. Br J Dermatol 2022; 187:773-777. [PMID: 35822506 DOI: 10.1111/bjd.21766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 07/03/2022] [Accepted: 07/09/2022] [Indexed: 12/01/2022]
Abstract
The phenotypic spectrum of genodermatoses is continuously expanding. Three siblings were referred because of a highly unusual phenotype comprising alopecia, dystrophic nails, palmoplantar keratoderma, and trauma-induced skin blistering. Whole exome sequencing analysis identified a heterozygous large genomic alteration of ~116,0000 bp resulting in the deletion of the KRT9, KRT14, KRT15, KRT16, KRT19 genes as well as part of KRT17. This genomic change leads to the generation of a truncated KRT17 protein composed of the first 3 exons of the gene and part of intron 3. The three patients were found to carry the heterozygous genomic deletion while their healthy parents did not, indicative of germline mosaicism. The genomic alteration was found to result in reduced KRT17 expression in patient skin. More importantly, the abnormal truncated KRT17 was found to exert a deleterious effect on keratinocyte cytoskeleton formation, leading to keratin aggregation. Co-expression of wildtype and truncated KRT17 proteins also caused keratin aggregation, demonstrating that the deletion exerts a dominant negative effect. In conclusion, we are reporting on a novel clinical phenotype that was found to result from germline mosaicism for a large genomic deletion spanning 6 keratin genes, thus expanding the spectrum of clinical manifestations associated with keratin disorders.
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Affiliation(s)
- Janan Mohamad
- Division of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ofer Sarig
- Division of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Paula Beattie
- Department of Dermatology, Royal Hospital for Children, Glasgow, United Kingdom
| | - Kiril Malovitski
- Division of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sari Assaf
- Division of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Edel O'Toole
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.,Department of Dermatology, The Royal London Hospital, London, United Kingdom
| | | | - Holly Evans
- Pachyonychia Congenita Project, Holladay, Utah, USA
| | - Liat Samuelov
- Division of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eli Sprecher
- Division of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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5
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Green KJ, Niessen CM, Rübsam M, Perez White BE, Broussard JA. The Desmosome-Keratin Scaffold Integrates ErbB Family and Mechanical Signaling to Polarize Epidermal Structure and Function. Front Cell Dev Biol 2022; 10:903696. [PMID: 35686051 PMCID: PMC9171019 DOI: 10.3389/fcell.2022.903696] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/06/2022] [Indexed: 11/29/2022] Open
Abstract
While classic cadherin-actin connections in adherens junctions (AJs) have ancient origins, intermediate filament (IF) linkages with desmosomal cadherins arose in vertebrate organisms. In this mini-review, we discuss how overlaying the IF-desmosome network onto the existing cadherin-actin network provided new opportunities to coordinate tissue mechanics with the positioning and function of chemical signaling mediators in the ErbB family of receptor tyrosine kinases. We focus in particular on the complex multi-layered outer covering of the skin, the epidermis, which serves essential barrier and stress sensing/responding functions in terrestrial vertebrates. We will review emerging data showing that desmosome-IF connections, AJ-actin interactions, ErbB family members, and membrane tension are all polarized across the multiple layers of the regenerating epidermis. Importantly, their integration generates differentiation-specific roles in each layer of the epidermis that dictate the form and function of the tissue. In the basal layer, the onset of the differentiation-specific desmosomal cadherin desmoglein 1 (Dsg1) dials down EGFR signaling while working with classic cadherins to remodel cortical actin cytoskeleton and decrease membrane tension to promote cell delamination. In the upper layers, Dsg1 and E-cadherin cooperate to maintain high tension and tune EGFR and ErbB2 activity to create the essential tight junction barrier. Our final outlook discusses the emerging appreciation that the desmosome-IF scaffold not only creates the architecture required for skin's physical barrier but also creates an immune barrier that keeps inflammation in check.
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Affiliation(s)
- Kathleen J. Green
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL, United States
| | - Carien M. Niessen
- Department Cell Biology of the Skin, University Hospital of Cologne, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Stress Responses in Aging-associated Diseases (CECAD), University Hospital of Cologne, University of Cologne, Cologne, Germany
- Center for Molecular Medicine (CMMC), University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Matthias Rübsam
- Department Cell Biology of the Skin, University Hospital of Cologne, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Stress Responses in Aging-associated Diseases (CECAD), University Hospital of Cologne, University of Cologne, Cologne, Germany
- Center for Molecular Medicine (CMMC), University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Bethany E. Perez White
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL, United States
| | - Joshua A. Broussard
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL, United States
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6
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Vetter A, Beier LS, Bouameur JE, Magin TM. Keratins modulate cellular redox homeostasis and mitochondrial dynamics. J Invest Dermatol 2021; 142:2264-2267.e6. [PMID: 34974054 DOI: 10.1016/j.jid.2021.12.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Alyssa Vetter
- Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, Phillip-Rosenthal-Straße 55, 04103 Leipzig, Germany.
| | - Laura-Sophie Beier
- Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, Phillip-Rosenthal-Straße 55, 04103 Leipzig, Germany
| | - Jamal-Eddine Bouameur
- Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, Phillip-Rosenthal-Straße 55, 04103 Leipzig, Germany
| | - Thomas M Magin
- Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, Phillip-Rosenthal-Straße 55, 04103 Leipzig, Germany
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7
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Indra I, Troyanovsky RB, Green KJ, Troyanovsky SM. Plakophilin 3 and Par3 facilitate desmosomes' association with the apical junctional complex. Mol Biol Cell 2021; 32:1824-1837. [PMID: 34260281 PMCID: PMC8684708 DOI: 10.1091/mbc.e21-01-0001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Desmosomes (DSMs), together with adherens junctions (AJs) and tight junctions (TJs), constitute the apical cell junctional complex (AJC). While the importance of the apical and basolateral polarity machinery in the organization of AJs and TJs is well established, how DSMs are positioned within the AJC is not understood. Here we use highly polarized DLD1 cells as a model to address how DSMs integrate into the AJC. We found that knockout (KO) of the desmosomal ARM protein Pkp3, but not other major DSM proteins, uncouples DSMs from the AJC without blocking DSM assembly. DLD1 cells also exhibit a prominent extraDSM pool of Pkp3, concentrated in tricellular (tC) contacts. Probing distinct apicobasal polarity pathways revealed that neither the DSM’s association with AJC nor the extraDSM pool of Pkp3 are abolished in cells with defects in Scrib module proteins responsible for basolateral membrane development. However, a loss of the apical polarity protein, Par3, completely eliminates the extraDSM pool of Pkp3 and disrupts AJC localization of desmosomes, dispersing these junctions along the entire length of cell–cell contacts. Our data are consistent with a model whereby Par3 facilitates DSM assembly within the AJC, controlling the availability of an assembly competent pool of Pkp3 stored in tC contacts.
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Affiliation(s)
| | | | - Kathleen J Green
- Departments of Pathology and Dermatology, Northwestern University, The Feinberg School of Medicine, Chicago, IL 60611
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8
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Laly AC, Sliogeryte K, Pundel OJ, Ross R, Keeling MC, Avisetti D, Waseem A, Gavara N, Connelly JT. The keratin network of intermediate filaments regulates keratinocyte rigidity sensing and nuclear mechanotransduction. SCIENCE ADVANCES 2021; 7:7/5/eabd6187. [PMID: 33571121 PMCID: PMC7840118 DOI: 10.1126/sciadv.abd6187] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 12/09/2020] [Indexed: 05/03/2023]
Abstract
The keratin network of intermediate filaments provides keratinocytes with essential mechanical strength and resilience, but the contribution to mechanosensing remains poorly understood. Here, we investigated the role of the keratin cytoskeleton in the response to altered matrix rigidity. We found that keratinocytes adapted to increasing matrix stiffness by forming a rigid, interconnected network of keratin bundles, in conjunction with F-actin stress fiber formation and increased cell stiffness. Disruption of keratin stability by overexpression of the dominant keratin 14 mutation R416P inhibited the normal mechanical response to substrate rigidity, reducing F-actin stress fibers and cell stiffness. The R416P mutation also impaired mechanotransduction to the nuclear lamina, which mediated stiffness-dependent chromatin remodeling. By contrast, depletion of the cytolinker plectin had the opposite effect and promoted increased mechanoresponsiveness and up-regulation of lamin A/C. Together, these results demonstrate that the keratin cytoskeleton plays a key role in matrix rigidity sensing and downstream signal transduction.
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Affiliation(s)
- Ana C Laly
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Kristina Sliogeryte
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Oscar J Pundel
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Rosie Ross
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Michael C Keeling
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Deepa Avisetti
- Centre for Oral Immunobiology and Regenerative Medicine, Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ahmad Waseem
- Centre for Oral Immunobiology and Regenerative Medicine, Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Núria Gavara
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
- Serra-Hunter Program, Biophysics and Bioengineering Unit, Department of Biomedicine, University of Barcelona, Barcelona, Spain
| | - John T Connelly
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
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9
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Keratin intermediate filaments: intermediaries of epithelial cell migration. Essays Biochem 2020; 63:521-533. [PMID: 31652439 DOI: 10.1042/ebc20190017] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/13/2019] [Accepted: 09/25/2019] [Indexed: 12/12/2022]
Abstract
Migration of epithelial cells is fundamental to multiple developmental processes, epithelial tissue morphogenesis and maintenance, wound healing and metastasis. While migrating epithelial cells utilize the basic acto-myosin based machinery as do other non-epithelial cells, they are distinguished by their copious keratin intermediate filament (KF) cytoskeleton, which comprises differentially expressed members of two large multigene families and presents highly complex patterns of post-translational modification. We will discuss how the unique mechanophysical and biochemical properties conferred by the different keratin isotypes and their modifications serve as finely tunable modulators of epithelial cell migration. We will furthermore argue that KFs together with their associated desmosomal cell-cell junctions and hemidesmosomal cell-extracellular matrix (ECM) adhesions serve as important counterbalances to the contractile acto-myosin apparatus either allowing and optimizing directed cell migration or preventing it. The differential keratin expression in leaders and followers of collectively migrating epithelial cell sheets provides a compelling example of isotype-specific keratin functions. Taken together, we conclude that the expression levels and specific combination of keratins impinge on cell migration by conferring biomechanical properties on any given epithelial cell affecting cytoplasmic viscoelasticity and adhesion to neighboring cells and the ECM.
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10
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Zimmer SE, Kowalczyk AP. The desmosome as a model for lipid raft driven membrane domain organization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183329. [PMID: 32376221 DOI: 10.1016/j.bbamem.2020.183329] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/20/2020] [Accepted: 04/23/2020] [Indexed: 01/14/2023]
Abstract
Desmosomes are cadherin-based adhesion structures that mechanically couple the intermediate filament cytoskeleton of adjacent cells to confer mechanical stress resistance to tissues. We have recently described desmosomes as mesoscale lipid raft membrane domains that depend on raft dynamics for assembly, function, and disassembly. Lipid raft microdomains are regions of the plasma membrane enriched in sphingolipids and cholesterol. These domains participate in membrane domain heterogeneity, signaling and membrane trafficking. Cellular structures known to be dependent on raft dynamics include the post-synaptic density in neurons, the immunological synapse, and intercellular junctions, including desmosomes. In this review, we discuss the current state of the desmosome field and put forward new hypotheses for the role of lipid rafts in desmosome adhesion, signaling and epidermal homeostasis. Furthermore, we propose that differential lipid raft affinity of intercellular junction proteins is a central driving force in the organization of the epithelial apical junctional complex.
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Affiliation(s)
- Stephanie E Zimmer
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322, United States of America; Department of Cell Biology, Emory University, Atlanta, GA 30322, United States of America
| | - Andrew P Kowalczyk
- Department of Cell Biology, Emory University, Atlanta, GA 30322, United States of America; Department of Dermatology, Emory University, Atlanta, GA 30322, United States of America.
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11
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Brás MM, Radmacher M, Sousa SR, Granja PL. Melanoma in the Eyes of Mechanobiology. Front Cell Dev Biol 2020; 8:54. [PMID: 32117980 PMCID: PMC7027391 DOI: 10.3389/fcell.2020.00054] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 01/21/2020] [Indexed: 12/23/2022] Open
Abstract
Skin is the largest organ of the human body with several important functions that can be impaired by injury, genetic or chronic diseases. Among all skin diseases, melanoma is one of the most severe, which can lead to death, due to metastization. Mechanotransduction has a crucial role for motility, invasion, adhesion and metastization processes, since it deals with the response of cells to physical forces. Signaling pathways are important to understand how physical cues produced or mediated by the Extracellular Matrix (ECM), affect healthy and tumor cells. During these processes, several molecules in the nucleus and cytoplasm are activated. Melanocytes, keratinocytes, fibroblasts and the ECM, play a crucial role in melanoma formation. This manuscript will address the synergy among melanocytes, keratinocytes, fibroblasts cells and the ECM considering their mechanical contribution and relevance in this disease. Mechanical properties of melanoma cells can also be influenced by pigmentation, which can be associated with changes in stiffness. Mechanical changes can be related with the adhesion, migration, or invasiveness potential of melanoma cells promoting a high metastization capacity of this cancer. Mechanosensing, mechanotransduction, and mechanoresponse will be highlighted with respect to the motility, invasion, adhesion and metastization in melanoma cancer.
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Affiliation(s)
- M. Manuela Brás
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
| | | | - Susana R. Sousa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Porto, Portugal
| | - Pedro L. Granja
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
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12
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Moch M, Schwarz N, Windoffer R, Leube RE. The keratin-desmosome scaffold: pivotal role of desmosomes for keratin network morphogenesis. Cell Mol Life Sci 2020; 77:543-558. [PMID: 31243490 PMCID: PMC7010626 DOI: 10.1007/s00018-019-03198-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/09/2019] [Accepted: 06/17/2019] [Indexed: 11/29/2022]
Abstract
Desmosome-anchored keratin intermediate filaments (KFs) are essential for epithelial coherence. Yet, desmosomal KF attachment and network organization are still unexplored in vivo. We, therefore, monitored KF network morphogenesis in fluorescent keratin 8 knock-in murine embryos revealing keratin enrichment at newly formed desmosomes followed by KF formation, KF elongation and KF fusion. To examine details of this process and its coupling to desmosome formation, we studied fluorescent keratin and desmosomal protein reporter dynamics in the periphery of expanding HaCaT keratinocyte colonies. Less than 3 min after the start of desmosomal proteins clustering non-filamentous keratin enriched at these sites followed by KF formation and elongation. Subsequently, desmosome-anchored KFs merged into stable bundles generating a rim-and-spokes system consisting of subcortical KFs connecting desmosomes to each other and radial KFs connecting desmosomes to the cytoplasmic KF network. We conclude that desmosomes are organizing centers for the KF cytoskeleton with a hitherto unknown nucleation capacity.
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Affiliation(s)
- Marcin Moch
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany
| | - Nicole Schwarz
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany
| | - Reinhard Windoffer
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany.
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13
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Wang X, Xu G, Yang N, Yan Y, Wu G, Sun C. Differential proteomic analysis revealed crucial egg white proteins for hatchability of chickens. Poult Sci 2019; 98:7076-7089. [PMID: 31424521 PMCID: PMC8913984 DOI: 10.3382/ps/pez459] [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: 03/27/2019] [Accepted: 07/26/2019] [Indexed: 11/20/2022] Open
Abstract
For healthy development, an avian embryo needs the nutritional and functional molecules maternally deposited in avian eggs. Egg white not only provides nutritional components but also exhibits functional properties, such as defenses against microbial invasion. However, the roles of the more detailed messages in embryo development remain unclear. In this study, a tandem mass tag labeling quantitation approach was used to innovatively identify the differential proteins in the egg whites of fresh eggs produced by hens with divergent high/low hatchability and in the egg whites of embryonated eggs with healthy and dead embryos. A total of 378 proteins were quantified in egg white, which is the most complete proteome identified for egg white to date, and up to 102 differential proteins were identified. GO enrichment, pathway, and hierarchical clustering analysis revealed some of the differential proteins that are the main participants in several biological processes, including blood coagulation, intermediate filament, antibacterial activity, and neurodevelopment. A list of 11 putative protein biomarkers, such as keratin (KRT19, KRT12, KRT15, and KRT6A), which is involved in cell architecture, and fibrinogen (fibrinogen alpha chain, fibrinogen beta chain, and fibrinogen gamma chain), which is related to blood coagulation, were ultimately screened. The current study screened egg white proteins that can predict low hatchability and embryonic death and deciphered the role of these proteins in embryonic development, which is meaningful for the comprehensive understanding of embryonic growth.
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Affiliation(s)
- Xiqiong Wang
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Guiyun Xu
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Ning Yang
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Yiyuan Yan
- Beijing Engineering Research Center of Layer, Beijing 101206, China
| | - Guiqin Wu
- Beijing Engineering Research Center of Layer, Beijing 101206, China
| | - Congjiao Sun
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
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14
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Klymkowsky MW. Filaments and phenotypes: cellular roles and orphan effects associated with mutations in cytoplasmic intermediate filament proteins. F1000Res 2019; 8. [PMID: 31602295 PMCID: PMC6774051 DOI: 10.12688/f1000research.19950.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/20/2019] [Indexed: 12/11/2022] Open
Abstract
Cytoplasmic intermediate filaments (IFs) surround the nucleus and are often anchored at membrane sites to form effectively transcellular networks. Mutations in IF proteins (IFps) have revealed mechanical roles in epidermis, muscle, liver, and neurons. At the same time, there have been phenotypic surprises, illustrated by the ability to generate viable and fertile mice null for a number of IFp-encoding genes, including vimentin. Yet in humans, the vimentin ( VIM) gene displays a high probability of intolerance to loss-of-function mutations, indicating an essential role. A number of subtle and not so subtle IF-associated phenotypes have been identified, often linked to mechanical or metabolic stresses, some of which have been found to be ameliorated by the over-expression of molecular chaperones, suggesting that such phenotypes arise from what might be termed "orphan" effects as opposed to the absence of the IF network per se, an idea originally suggested by Toivola et al. and Pekny and Lane.
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Affiliation(s)
- Michael W Klymkowsky
- Molecular, Cellular & Developmental Biology, University of Colorado, Boulder, Boulder, CO, 80303, USA
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15
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Egu D, Sigmund A, Schmidt E, Spindler V, Walter E, Waschke J. A new
ex vivo
human oral mucosa model reveals that p38
MAPK
inhibition is not effective in preventing autoantibody‐induced mucosal blistering in pemphigus. Br J Dermatol 2019; 182:987-994. [DOI: 10.1111/bjd.18237] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2019] [Indexed: 02/06/2023]
Affiliation(s)
- D.T. Egu
- Chair of Vegetative Anatomy Institute of Anatomy Faculty of Medicine LMU Munich Germany
| | - A.M. Sigmund
- Chair of Vegetative Anatomy Institute of Anatomy Faculty of Medicine LMU Munich Germany
| | - E. Schmidt
- Lübeck Institute of Experimental Dermatology University of Lübeck LübeckGermany
- Department of Dermatology, Allergology and Venereology University of Lübeck Lübeck Germany
| | - V. Spindler
- Chair of Vegetative Anatomy Institute of Anatomy Faculty of Medicine LMU Munich Germany
- Department of Biomedicine University of Basel Basel Switzerland
| | - E. Walter
- Chair of Vegetative Anatomy Institute of Anatomy Faculty of Medicine LMU Munich Germany
| | - J. Waschke
- Chair of Vegetative Anatomy Institute of Anatomy Faculty of Medicine LMU Munich Germany
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16
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Ji K, Fan R, Zhang J, Yang S, Dong C. Long non-coding RNA expression profile in Cdk5-knockdown mouse skin. Gene 2018; 672:195-201. [DOI: 10.1016/j.gene.2018.05.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 05/27/2018] [Accepted: 05/31/2018] [Indexed: 01/16/2023]
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17
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Schlögl E, Radeva MY, Vielmuth F, Schinner C, Waschke J, Spindler V. Keratin Retraction and Desmoglein3 Internalization Independently Contribute to Autoantibody-Induced Cell Dissociation in Pemphigus Vulgaris. Front Immunol 2018; 9:858. [PMID: 29922278 PMCID: PMC5996934 DOI: 10.3389/fimmu.2018.00858] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/06/2018] [Indexed: 01/12/2023] Open
Abstract
Pemphigus vulgaris (PV) is a potentially lethal autoimmune disease characterized by blister formation of the skin and mucous membranes and is caused by autoantibodies against desmoglein (Dsg) 1 and Dsg3. Dsg1 and Dsg3 are linked to keratin filaments in desmosomes, adhering junctions abundant in tissues exposed to high levels of mechanical stress. The binding of the autoantibodies leads to internalization of Dsg3 and a collapse of the keratin cytoskeleton-yet, the relevance and interdependence of these changes for loss of cell-cell adhesion and blistering is poorly understood. In live-cell imaging studies, loss of the keratin network at the cell periphery was detectable starting after 60 min of incubation with immunoglobulin G fractions of PV patients (PV-IgG). These rapid changes correlated with loss of cell-cell adhesion detected by dispase-based dissociation assays and were followed by a condensation of keratin filaments into thick bundles after several hours. Dsg3 internalization started at 90 min of PV-IgG treatment, thus following the early keratin changes. By inhibiting casein kinase 1 (CK-1), we provoked keratin alterations resembling the effects of PV-IgG. Although CK-1-induced loss of peripheral keratin network correlated with loss of cell cohesion and Dsg3 clustering in the membrane, it was not sufficient to trigger the internalization of Dsg3. However, additional incubation with PV-IgG was effective to promote Dsg3 loss at the membrane, indicating that Dsg3 internalization is independent from keratin alterations. Vice versa, inhibiting Dsg3 internalization did not prevent PV-IgG-induced keratin retraction and only partially rescued cell cohesion. Together, keratin changes appear very early after autoantibody binding and temporally overlap with loss of cell cohesion. These early alterations appear to be distinct from Dsg3 internalization, suggesting a crucial role for initial loss of cell cohesion in PV.
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Affiliation(s)
- Elisabeth Schlögl
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Mariya Y Radeva
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Franziska Vielmuth
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Camilla Schinner
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Jens Waschke
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Volker Spindler
- Chair of Vegetative Anatomy, Faculty of Medicine, Institute of Anatomy, Ludwig Maximilian University of Munich, Munich, Germany.,Department of Biomedicine, University of Basel, Basel, Switzerland
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18
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Xue K, Zheng Y, Cui Y. A novel heterozygous missense mutation of DSP in a Chinese Han pedigree with palmoplantar keratoderma. J Cosmet Dermatol 2018; 18:371-376. [PMID: 29607617 DOI: 10.1111/jocd.12533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND Mutations in the desmoplakin (DSP) gene have been demonstrated to be associated with lethal acantholytic epidermolysis bullosa, cardiomyopathy, and palmoplantar keratoderma (PPK). AIMS To better understand the relationship between PPK and the gene mutations in DSP. METHODS A pedigree of PPK was subjected to heterozygous missense mutation analysis in the DSP gene. Dermoscopy, reflectance confocal microscopy, and histopathological examination were performed from each epidermis layer in this study. Samples were derived from the blood of patients and normal healthy controls. DSP gene sequence analysis and Q-PCR analysis was performed for evaluating DSP gene mutation and expression. RESULTS A novel heterozygous missense mutation c.3550 C>T in the coding region of the DSP gene, predicting substitution of arginine (Arg,R) by tryptophan (Trp,W) in the desmoplakin polypeptide, was discovered in a Chinese pedigree of PPK. In the meanwhile, this mutation was not found in 100 healthy individuals. CONCLUSIONS The novel missense mutation c.3550 C>T(p.Arg1184Trp) of DSP gene expanded the mutation spectrum in palmoplantar keratoderma.
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Affiliation(s)
- Ke Xue
- Department of Dermatology, China-Japan Friendship Hospital, Beijing, China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Yajie Zheng
- Institute of Dermatology and Department of Dermatology, the First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Yong Cui
- Department of Dermatology, China-Japan Friendship Hospital, Beijing, China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
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19
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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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20
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Sanghvi-Shah R, Weber GF. Intermediate Filaments at the Junction of Mechanotransduction, Migration, and Development. Front Cell Dev Biol 2017; 5:81. [PMID: 28959689 PMCID: PMC5603733 DOI: 10.3389/fcell.2017.00081] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/30/2017] [Indexed: 01/04/2023] Open
Abstract
Mechanically induced signal transduction has an essential role in development. Cells actively transduce and respond to mechanical signals and their internal architecture must manage the associated forces while also being dynamically responsive. With unique assembly-disassembly dynamics and physical properties, cytoplasmic intermediate filaments play an important role in regulating cell shape and mechanical integrity. While this function has been recognized and appreciated for more than 30 years, continually emerging data also demonstrate important roles of intermediate filaments in cell signal transduction. In this review, with a particular focus on keratins and vimentin, the relationship between the physical state of intermediate filaments and their role in mechanotransduction signaling is illustrated through a survey of current literature. Association with adhesion receptors such as cadherins and integrins provides a critical interface through which intermediate filaments are exposed to forces from a cell's environment. As a consequence, these cytoskeletal networks are posttranslationally modified, remodeled and reorganized with direct impacts on local signal transduction events and cell migratory behaviors important to development. We propose that intermediate filaments provide an opportune platform for cells to both cope with mechanical forces and modulate signal transduction.
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Affiliation(s)
- Rucha Sanghvi-Shah
- Department of Biological Sciences, Rutgers University-NewarkNewark, NJ, United States
| | - Gregory F Weber
- Department of Biological Sciences, Rutgers University-NewarkNewark, NJ, United States
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21
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Vielmuth F, Wanuske MT, Radeva MY, Hiermaier M, Kugelmann D, Walter E, Buechau F, Magin TM, Waschke J, Spindler V. Keratins Regulate the Adhesive Properties of Desmosomal Cadherins through Signaling. J Invest Dermatol 2017; 138:121-131. [PMID: 28899688 DOI: 10.1016/j.jid.2017.08.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/10/2017] [Accepted: 08/06/2017] [Indexed: 11/17/2022]
Abstract
Tightly controlled intercellular adhesion is crucial for the integrity and function of the epidermis. The keratin filament cytoskeleton anchors desmosomes, supramolecular complexes required for strong intercellular adhesion. We tested whether keratin filaments control cell adhesion by regulating the adhesive properties of desmosomal cadherins such as desmoglein (Dsg) 3. Atomic force microscopy and fluorescence recovery after photobleaching experiments showed reduced Dsg3 adhesive forces and membrane stability in murine keratinocytes lacking all keratin filaments. Impairment of the actin cytoskeleton also resulted in decreased Dsg3 immobilization but did not affect Dsg3 binding properties, indicating that the latter are exclusively controlled by keratins. Reduced binding forces were dependent on p38 mitogen-activated protein kinase activity, which was deregulated in keratin-deficient cells. In contrast, inhibition of protein kinase C signaling, which is known to be controlled by keratins, promoted and spatially stabilized Dsg3-mediated interactions in the membrane. These results show a previously unreported mechanism for how keratins stabilize intercellular adhesion on the level of single desmosomal adhesion molecules.
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Affiliation(s)
- Franziska Vielmuth
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Marie-Therès Wanuske
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Mariya Y Radeva
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Matthias Hiermaier
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Daniela Kugelmann
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Elias Walter
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Fanny Buechau
- Institute of Biology and Translational Center for Regenerative Medicine, Sächsischer Inkubator für klinische Translation, University of Leipzig, Leipzig, Germany
| | - Thomas M Magin
- Institute of Biology and Translational Center for Regenerative Medicine, Sächsischer Inkubator für klinische Translation, University of Leipzig, Leipzig, Germany
| | - Jens Waschke
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany.
| | - Volker Spindler
- Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany.
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22
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Hatzfeld M, Keil R, Magin TM. Desmosomes and Intermediate Filaments: Their Consequences for Tissue Mechanics. Cold Spring Harb Perspect Biol 2017; 9:a029157. [PMID: 28096266 PMCID: PMC5453391 DOI: 10.1101/cshperspect.a029157] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Adherens junctions (AJs) and desmosomes connect the actin and keratin filament networks of adjacent cells into a mechanical unit. Whereas AJs function in mechanosensing and in transducing mechanical forces between the plasma membrane and the actomyosin cytoskeleton, desmosomes and intermediate filaments (IFs) provide mechanical stability required to maintain tissue architecture and integrity when the tissues are exposed to mechanical stress. Desmosomes are essential for stable intercellular cohesion, whereas keratins determine cell mechanics but are not involved in generating tension. Here, we summarize the current knowledge of the role of IFs and desmosomes in tissue mechanics and discuss whether the desmosome-keratin scaffold might be actively involved in mechanosensing and in the conversion of chemical signals into mechanical strength.
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Affiliation(s)
- Mechthild Hatzfeld
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06114 Halle, Germany
| | - René Keil
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06114 Halle, Germany
| | - Thomas M Magin
- Institute of Biology, Division of Cell and Developmental Biology and Saxonian Incubator for Clinical Translation (SIKT), University of Leipzig, 04103 Leipzig, Germany
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23
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Abstract
Epidermolytic ichthyosis (EI) is a rare disorder of cornification caused by mutations in KRT1 and KRT10, encoding two suprabasal epidermal keratins. Because of the variable clinical features and severity of the disease, histopathology is often required to correctly direct the molecular analysis. EI is characterized by hyperkeratosis and vacuolar degeneration of the upper epidermis, also known as epidermolytic hyperkeratosis, hence the name of the disease. In the current report, the authors describe members of 2 families presenting with clinical features consistent with EI. The patients were shown to carry classical mutations in KRT1 or KRT10, but did not display epidermolytic changes on histology. These observations underscore the need to remain aware of the limitations of pathological features when considering a diagnosis of EI.
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24
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25
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Kumar V, Behr M, Kiritsi D, Scheffschick A, Grahnert A, Homberg M, Schwieger-Briel A, Jakob T, Bruckner-Tuderman L, Magin TM. Keratin-dependent thymic stromal lymphopoietin expression suggests a link between skin blistering and atopic disease. J Allergy Clin Immunol 2016; 138:1461-1464.e6. [DOI: 10.1016/j.jaci.2016.04.046] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 04/01/2016] [Accepted: 04/12/2016] [Indexed: 12/16/2022]
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26
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FAM83H and casein kinase I regulate the organization of the keratin cytoskeleton and formation of desmosomes. Sci Rep 2016; 6:26557. [PMID: 27222304 PMCID: PMC4879633 DOI: 10.1038/srep26557] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 05/05/2016] [Indexed: 12/23/2022] Open
Abstract
FAM83H is essential for the formation of dental enamel because a mutation in the FAM83H gene causes amelogenesis imperfecta (AI). We previously reported that the overexpression of FAM83H often occurs and disorganizes the keratin cytoskeleton in colorectal cancer cells. We herein show that FAM83H regulates the organization of the keratin cytoskeleton and maintains the formation of desmosomes in ameloblastoma cells. FAM83H is expressed and localized on keratin filaments in human ameloblastoma cell lines and in mouse ameloblasts and epidermal germinative cells in vivo. FAM83H shows preferential localization to keratin filaments around the nucleus that often extend to cell-cell junctions. Alterations in the function of FAM83H by its overexpression, knockdown, or an AI-causing truncated mutant prevent the proper organization of the keratin cytoskeleton in ameloblastoma cells. Furthermore, the AI-causing mutant prevents desmosomal proteins from being localized to cell-cell junctions. The effects of the AI-causing mutant depend on its binding to and possible inhibition of casein kinase I (CK-1). The suppression of CK-1 by its inhibitor, D4476, disorganizes the keratin cytoskeleton. Our results suggest that AI caused by the FAM83H mutation is mediated by the disorganization of the keratin cytoskeleton and subsequent disruption of desmosomes in ameloblasts.
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27
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Salas PJ, Forteza R, Mashukova A. Multiple roles for keratin intermediate filaments in the regulation of epithelial barrier function and apico-basal polarity. Tissue Barriers 2016; 4:e1178368. [PMID: 27583190 PMCID: PMC4993576 DOI: 10.1080/21688370.2016.1178368] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 12/27/2022] Open
Abstract
As multicellular organisms evolved a family of cytoskeletal proteins, the keratins (types I and II) expressed in epithelial cells diversified in more than 20 genes in vertebrates. There is no question that keratin filaments confer mechanical stiffness to cells. However, such a number of genes can hardly be explained by evolutionary advantages in mechanical features. The use of transgenic mouse models has revealed unexpected functional relationships between keratin intermediate filaments and intracellular signaling. Accordingly, loss of keratins or mutations in keratins that cause or predispose to human diseases, result in increased sensitivity to apoptosis, regulation of innate immunity, permeabilization of tight junctions, and mistargeting of apical proteins in different epithelia. Precise mechanistic explanations for these phenomena are still lacking. However, immobilization of membrane or cytoplasmic proteins, including chaperones, on intermediate filaments (“scaffolding”) appear as common molecular mechanisms and may explain the need for so many different keratin genes in vertebrates.
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Affiliation(s)
- Pedro J Salas
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Radia Forteza
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Anastasia Mashukova
- Department of Cell Biology, Miller School of Medicine, University of Miami, Miami, FL, USA; Department of Physiology, Nova Southeastern University, Fort Lauderdale, FL, USA
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Kumar V, Bouameur JE, Bär J, Rice RH, Hornig-Do HT, Roop DR, Schwarz N, Brodesser S, Thiering S, Leube RE, Wiesner RJ, Vijayaraj P, Brazel CB, Heller S, Binder H, Löffler-Wirth H, Seibel P, Magin TM. A keratin scaffold regulates epidermal barrier formation, mitochondrial lipid composition, and activity. J Cell Biol 2016; 211:1057-75. [PMID: 26644517 PMCID: PMC4674273 DOI: 10.1083/jcb.201404147] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epidermal keratin filaments are important components and organizers of the cornified envelope and regulate mitochondrial metabolism by modulating their membrane composition. Keratin intermediate filaments (KIFs) protect the epidermis against mechanical force, support strong adhesion, help barrier formation, and regulate growth. The mechanisms by which type I and II keratins contribute to these functions remain incompletely understood. Here, we report that mice lacking all type I or type II keratins display severe barrier defects and fragile skin, leading to perinatal mortality with full penetrance. Comparative proteomics of cornified envelopes (CEs) from prenatal KtyI−/− and KtyII−/−K8 mice demonstrates that absence of KIF causes dysregulation of many CE constituents, including downregulation of desmoglein 1. Despite persistence of loricrin expression and upregulation of many Nrf2 targets, including CE components Sprr2d and Sprr2h, extensive barrier defects persist, identifying keratins as essential CE scaffolds. Furthermore, we show that KIFs control mitochondrial lipid composition and activity in a cell-intrinsic manner. Therefore, our study explains the complexity of keratinopathies accompanied by barrier disorders by linking keratin scaffolds to mitochondria, adhesion, and CE formation.
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Affiliation(s)
- Vinod Kumar
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Jamal-Eddine Bouameur
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Janina Bär
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Robert H Rice
- Department of Environmental Toxicology, University of California, Davis, Davis, CA 95616
| | - Hue-Tran Hornig-Do
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, 50931 Cologne, Germany
| | - Dennis R Roop
- Department of Dermatology, University of Colorado, Denver, CO 80045 Charles C. Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Denver, CO 80045
| | - Nicole Schwarz
- Institute of Molecular and Cellular Anatomy, Rheinisch-Westfälische Technische Hochschule Aachen University, 52074 Aachen, Germany
| | - Susanne Brodesser
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, 50931 Cologne, Germany Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Medical Faculty, University of Cologne, 50931 Cologne, Germany Center for Molecular Medicine Cologne, 50931 Cologne, Germany
| | - Sören Thiering
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, Rheinisch-Westfälische Technische Hochschule Aachen University, 52074 Aachen, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, 50931 Cologne, Germany Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Medical Faculty, University of Cologne, 50931 Cologne, Germany Center for Molecular Medicine Cologne, 50931 Cologne, Germany
| | | | - Christina B Brazel
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Sandra Heller
- Center for Biotechnology and Biomedicine, 04103 Leipzig, Germany
| | - Hans Binder
- Interdisciplinary Centre for Bioinformatics, University of Leipzig, 04107 Leipzig, Germany
| | - Henry Löffler-Wirth
- Interdisciplinary Centre for Bioinformatics, University of Leipzig, 04107 Leipzig, Germany
| | - Peter Seibel
- Center for Biotechnology and Biomedicine, 04103 Leipzig, Germany
| | - Thomas M Magin
- Translational Centre for Regenerative Medicine Leipzig, University of Leipzig, 04103 Leipzig, Germany Institute of Biology, Division of Cell and Developmental Biology, University of Leipzig, 04103 Leipzig, Germany
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Robert A, Hookway C, Gelfand VI. Intermediate filament dynamics: What we can see now and why it matters. Bioessays 2016; 38:232-43. [PMID: 26763143 DOI: 10.1002/bies.201500142] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mechanical properties of vertebrate cells are largely defined by the system of intermediate filaments (IF). As part of a dense network, IF polymers are constantly rearranged and relocalized in the cell to fulfill their duty as cells change shape, migrate, or divide. With the development of new imaging technologies, such as photoconvertible proteins and super-resolution microscopy, a new appreciation for the complexity of IF dynamics has emerged. This review highlights new findings about the transport of IF, the remodeling of filaments by a process of severing and re-annealing, and the subunit exchange that occurs between filament precursors and a soluble pool of IF. We will also discuss the unique dynamic features of the keratin IF network. Finally, we will speculate about how the dynamic properties of IF are related to their functions.
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Affiliation(s)
- Amélie Robert
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Caroline Hookway
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Loschke F, Homberg M, Magin TM. Keratin Isotypes Control Desmosome Stability and Dynamics through PKCα. J Invest Dermatol 2016; 136:202-13. [DOI: 10.1038/jid.2015.403] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 09/04/2015] [Accepted: 09/11/2015] [Indexed: 02/08/2023]
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Homberg M, Ramms L, Schwarz N, Dreissen G, Leube RE, Merkel R, Hoffmann B, Magin TM. Distinct Impact of Two Keratin Mutations Causing Epidermolysis Bullosa Simplex on Keratinocyte Adhesion and Stiffness. J Invest Dermatol 2015; 135:2437-2445. [DOI: 10.1038/jid.2015.184] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/10/2015] [Accepted: 04/25/2015] [Indexed: 12/20/2022]
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Rodríguez-Fernández JL, de Lacoba MG. Plasma membrane-associated superstructure: Have we overlooked a new type of organelle in eukaryotic cells? J Theor Biol 2015; 380:346-58. [PMID: 26066286 DOI: 10.1016/j.jtbi.2015.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 05/22/2015] [Accepted: 05/25/2015] [Indexed: 10/23/2022]
Abstract
A variety of intriguing plasma membrane-associated regions, including focal adhesions, adherens junctions, tight junctions, immunological synapses, neuromuscular junctions and the primary cilia, among many others, have been described in eukaryotic cells. Emphasizing their importance, alteration in their molecular structures induces or correlates with different pathologies. These regions display surface proteins connected to intracellular molecules, including cytoskeletal component, which maintain their cytoarchitecture, and signalling proteins, which regulate their organization and functions. Based on the molecular similarities and other common features observed, we suggest that, despite differences in external appearances, all these regions are just the same superstructure that appears in different locations and cells. We hypothesize that this superstructure represents an overlooked new type of organelle that we call plasma membrane-associated superstructure (PMAS). Therefore, we suggest that eukaryotic cells include classical organelles (e.g. mitochondria, Golgi and others) and also PMAS. We speculate that this new type of organelle might be an innovation associated to the emergence of eukaryotes. Finally we discuss the implications of the hypothesis proposed.
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Affiliation(s)
- José Luis Rodríguez-Fernández
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, Madrid 28040, Spain.
| | - Mario García de Lacoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, Madrid 28040, Spain
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A Drosophila Model of Epidermolysis Bullosa Simplex. J Invest Dermatol 2015; 135:2031-2039. [PMID: 25830653 PMCID: PMC4519992 DOI: 10.1038/jid.2015.129] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/16/2015] [Accepted: 03/24/2015] [Indexed: 12/03/2022]
Abstract
The blistering skin disorder Epidermolysis bullosa simplex (EBS) results from dominant mutations in K5 or K14 genes, encoding the intermediate filament network of basal epidermal keratinocytes. The mechanisms governing keratin network formation and collapse due to EBS mutations remain incompletely understood. Drosophila lacks cytoplasmic intermediate filaments, providing a ‚null’ environment to examine the formation of keratin networks and determine mechanisms by which mutant keratins cause pathology. Here, we report that ubiquitous co-expression of transgenes encoding wild-type human K14 and K5 resulted in the formation of extensive keratin networks in Drosophila epithelial and non-epithelial tissues, causing no overt phenotype. Similar to mammalian cells, treatment of transgenic fly tissues with phosphatase inhibitors caused keratin network collapse, validating Drosophila as a genetic model system to investigate keratin dynamics. Co-expression of K5 and a K14R125C mutant that causes the most severe form of EBS resulted in widespread formation of EBS-like cytoplasmic keratin aggregates in epithelial and non-epithelial fly tissues. Expression of K14R125C/K5 caused semi-lethality; adult survivors developed wing blisters and were flightless due to lack of intercellular adhesion during wing heart development. This Drosophila model of EBS is valuable for the identification of pathways altered by mutant keratins and for development of EBS therapies.
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Keratins Stabilize Hemidesmosomes through Regulation of β4-Integrin Turnover. J Invest Dermatol 2015; 135:1609-1620. [PMID: 25668239 DOI: 10.1038/jid.2015.46] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/12/2014] [Accepted: 12/31/2014] [Indexed: 01/16/2023]
Abstract
Epidermal integrity and wound healing depend on remodeling of cell-matrix contacts including hemidesmosomes. Mutations in β4-integrin and plectin lead to severe epidermolysis bullosa (EB). Whether mutations in keratins K5 or K14, which cause EB simplex, also compromise cell-matrix adhesion through altering hemidesmosomal components is not well investigated. In particular, the dependence of β4-integrin endocytosis and turnover on keratins remains incompletely understood. Here, we show that the absence of keratins causes loss of plectin-β4-integrin interaction and elevated β4-integrin phosphorylation at Ser1354 and Ser1362. This triggered a caveolin-dependent endocytosis of β4-integrin but not of other integrins through Rab5 and Rab11 compartments in keratinocytes. Expressing a phospho-deficient β4-integrin mutant reduces β4-integrin endocytosis and rescues plectin localization in keratin-free cells. β4-integrin phosphorylation in the absence of keratins resulted from elevated Erk1/2 activity downstream of increased EGFR and PKCα signaling. Further, increased Erk1/2 phosphorylation and altered plectin localization occur in keratin-deficient mouse epidermis in vivo. Strikingly, expression of the K14-R125P EBS mutant also resulted in plectin mislocalization and elevated β4-integrin turnover, suggesting disease relevance. Our data underscore a major role of keratins in controlling β4-integrin endocytosis involving a plectin-Erk1/2-dependent mechanism relevant for epidermal differentiation and pathogenesis.
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36
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Regulation of keratin network organization. Curr Opin Cell Biol 2015; 32:56-64. [PMID: 25594948 DOI: 10.1016/j.ceb.2014.12.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 11/10/2014] [Accepted: 12/19/2014] [Indexed: 12/31/2022]
Abstract
Keratins form the major intermediate filament cytoskeleton of epithelia and are assembled from heterodimers of 28 type I and 26 type II keratins in cell- and differentiation-dependent patterns. By virtue of their primary sequence composition, interactions with cell adhesion complexes and components of major signaling cascades, keratins act as targets and effectors of mechanical force and chemical signals to determine cell mechanics, epithelial cohesion and modulate signaling in keratin isotype-specific manners. Therefore, cell-specific keratin expression and organization impact on cell growth, migration and invasion. Here, we review the recent literature, focusing on the question how keratin networks are regulated and how the interplay of keratins with adhesion complexes affects these processes and provides a framework to understand keratins contribution to blistering and inflammatory disorders and to tumor metastasis.
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37
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Der Perng M, Quinlan RA. The Dynamic Duo of Small Heat Proteins and IFs Maintain Cell Homeostasis, Resist Cellular Stress and Enable Evolution in Cells and Tissues. HEAT SHOCK PROTEINS 2015. [DOI: 10.1007/978-3-319-16077-1_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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Osmani N, Labouesse M. Remodeling of keratin-coupled cell adhesion complexes. Curr Opin Cell Biol 2014; 32:30-8. [PMID: 25460779 DOI: 10.1016/j.ceb.2014.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/13/2014] [Accepted: 10/18/2014] [Indexed: 12/12/2022]
Abstract
Epithelial cells constitute the main barrier between the inside and outside of organs, acting as gatekeepers of their structure and integrity. Hemidesmosomes and desmosomes are respectively cell-matrix and cell-cell adhesions coupled to the intermediate filament cytoskeleton. These adhesions ensure mechanical integrity of the epithelial barrier. Although desmosomes and hemidesmosomes are essential in maintaining strong cell-cell and cell-matrix adhesions, there is an emerging view that they should be remodeled in order to maintain epithelial homeostasis. Here we review the adhesion properties of desmosomes and hemidesmosomes, as well as the mechanisms driving their remodeling. We also discuss recent data suggesting that keratin-coupled adhesion complexes can sense the biomechanical cellular environment and participate in the cellular response to such external cues.
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Affiliation(s)
- Naël Osmani
- IGBMC, Development and Stem Cells Program, 67400 Illkirch, France; CNRS (UMR 7104), 67400 Illkirch, France; INSERM (U964), 67400 Illkirch, France; Université de Strasbourg, 67400 Illkirch, France.
| | - Michel Labouesse
- IGBMC, Development and Stem Cells Program, 67400 Illkirch, France; CNRS (UMR 7104), 67400 Illkirch, France; INSERM (U964), 67400 Illkirch, France; Université de Strasbourg, 67400 Illkirch, France.
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Zupancic T, Stojan J, Lane EB, Komel R, Bedina-Zavec A, Liovic M. Intestinal cell barrier function in vitro is severely compromised by keratin 8 and 18 mutations identified in patients with inflammatory bowel disease. PLoS One 2014; 9:e99398. [PMID: 24915158 PMCID: PMC4051775 DOI: 10.1371/journal.pone.0099398] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 05/14/2014] [Indexed: 12/20/2022] Open
Abstract
Keratin 8 and 18 (K8/K18) mutations have been implicated in the aetiology of certain pathogenic processes of the liver and pancreas. While some K8 mutations (K8 G62C, K8 K464N) are also presumed susceptibility factors for inflammatory bowel disease (IBD), the only K18 mutation (K18 S230T) discovered so far in an IBD patient is thought to be a polymorphism. The aim of our study was to demonstrate that these mutations might also directly affect intestinal cell barrier function. Cell monolayers of genetically engineered human colonocytes expressing these mutations were tested for permeability, growth rate and resistance to heat-stress. We also calculated the change in dissociation constant (Kd, measure of affinity) each of these mutations introduces into the keratin protein, and present the first model of a keratin dimer L12 region with in silico clues to how the K18 S230T mutation may affect keratin function. Physiologically, these mutations cause up to 30% increase in paracellular permeability in vitro. Heat-stress induces little keratin clumping but instead cell monolayers peel off the surface suggesting a problem with cell junctions. K18 S230T has pronounced pathological effects in vitro marked by high Kd, low growth rate and increased permeability. The latter may be due to the altered distribution of tight junction components claudin-4 and ZO-1. This is the first time intestinal cells have been suggested also functionally impaired by K8/K18 mutations. Although an in vitro colonocyte model system does not completely mimic the epithelial lining of the intestine, nevertheless the data suggest that K8/K18 mutations may be also able to produce a phenotype in vivo.
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Affiliation(s)
- Tina Zupancic
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Jure Stojan
- Medical Centre for Molecular Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | | | - Radovan Komel
- National Institute of Chemistry, Ljubljana, Slovenia
- Medical Centre for Molecular Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | | | - Mirjana Liovic
- National Institute of Chemistry, Ljubljana, Slovenia
- Medical Centre for Molecular Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- * E-mail:
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Beyond expectations: novel insights into epidermal keratin function and regulation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:265-306. [PMID: 24952920 DOI: 10.1016/b978-0-12-800179-0.00007-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The epidermis is a stratified epithelium that relies on its cytoskeleton and cell junctions to protect the body against mechanical injury, dehydration, and infections. Keratin intermediate filament proteins are involved in many of these functions by forming cell-specific cytoskeletal scaffolds crucial for the maintenance of cell and tissue integrity. In response to various stresses, the expression and organization of keratins are altered at transcriptional and posttranslational levels to restore tissue homeostasis. Failure to restore tissue homeostasis in the presence of keratin gene mutations results in acute and chronic skin disorders for which currently no rational therapies are available. Here, we review the recent progress on the role of keratins in cytoarchitecture, adhesion, signaling, and inflammation. By focusing on epidermal keratins, we illustrate the contribution of keratin isotypes to differentiated epithelial functions.
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