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Zhang T, Xu Z, Zheng D, Wang X, He J, Zhang L, Zallocchi M. Novel biallelic variants in the PLEC gene are associated with severe hearing loss. Hear Res 2023; 436:108831. [PMID: 37393735 DOI: 10.1016/j.heares.2023.108831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 05/18/2023] [Accepted: 06/13/2023] [Indexed: 07/04/2023]
Abstract
Pediatric auditory neuropathy spectrum disorder is a particular type of hearing loss caused by abnormal sound transmission from the cochlea to the brain. It is due to defective peripheral synaptic function or improper neuronal conduction. Using trio whole-exome sequencing, we have identified novel biallelic variants in the PLEC gene in three individuals with profound deafness from two unrelated families. Among them, one pediatric patient diagnosed with auditory neuropathy spectrum disorder had a good cochlear implantation outcome. The other two adult patients were diagnosed with non-syndromic hearing loss. Studies in mice and zebrafish confirmed that plectin is developmentally expressed in the inner ear. Moreover, plectin's knockdown resulted in a reduction of synaptic mitochondrial potential and loss of ribbon synapses, reinforcing the idea of a role for plectin in neuronal transmission. Altogether, the results presented here, point to a new unconventional role for plectin in the inner ear. Contrary to the well-characterized association of plectin to skin and muscle diseases, we found that specific plectin mutations can result in hearing loss with no other clinical manifestations. This is important because 1) it provides evidence of plectin's involvement in inner ear function and 2) it will help clinicians at the time of diagnosis and treatment.
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Affiliation(s)
- Tianyang Zhang
- Department of Otolaryngology-Head and Neck Surgery, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, China; Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Zhenhang Xu
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, United States; Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, China.
| | - Danya Zheng
- Department of Otolaryngology-Head and Neck Surgery, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, China.
| | - Xuechun Wang
- Department of Otolaryngology-Head and Neck Surgery, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, China.
| | - Jingchun He
- Department of Otorhinolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Luping Zhang
- Department of Otolaryngology-Head and Neck Surgery, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, China.
| | - Marisa Zallocchi
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, United States.
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2
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Kotalevskaya YY, Stepanov VA. Molecular genetic basis of epidermolysis bullosa. Vavilovskii Zhurnal Genet Selektsii 2023; 27:18-27. [PMID: 36923479 PMCID: PMC10009482 DOI: 10.18699/vjgb-23-04] [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: 10/17/2022] [Revised: 12/10/2022] [Accepted: 12/20/2022] [Indexed: 03/11/2023] Open
Abstract
Epidermolysis bullosa (EB) is an inherited disorder of skin fragility, caused by mutations in a large number of genes associated with skin integrity and dermal-epidermal adhesion. Skin fragility is manifested by a decrease in resistance to external mechanical influences, the clinical signs of which are the formation of blisters, erosions and wounds on the skin and mucous membranes. EB is a multisystemic disease and characterized by a wide phenotypic spectrum with extracutaneous complications in severe types, besides the skin and mucous membranes, with high mortality. More than 30 clinical subtypes have been identified, which are grouped into four main types: simplex EB, junctional EB, dystrophic EB and Kindler syndrome. To date, pathogenic variants in 16 different genes are associated with EB and encode proteins that are part of the skin anchoring structures or are signaling proteins. Genetic mutations cause dysfunction of cellular structures, differentiation, proliferation and apoptosis of cells, leading to mechanical instability of the skin. The formation of reduced proteins or decrease in their level leads mainly to functional disorders, forming mild or intermediate severe phenotypes. Absent protein expression is a result of null genetic variants and leads to structural abnormalities, causing a severe clinical phenotype. For most of the genes involved in the pathogenesis of EB, certain relationships have been established between the type and position of genetic variant and the severity of the clinical manifestations of the disease. Establishing an accurate diagnosis depends on the correlation of clinical, genealogical and immunohistological data in combination with molecular genetic testing. In general, the study of clinical, genetic and ultrastructural changes in EB has significantly expanded the understanding of the natural history of the disease and supplemented the data on genotype-phenotype correlations, promotes the search and study of epigenetic and non-genetic disease modifier factors, and also allows developing approaches to radical treatment of the disease. New advances of sequencing technologies have made it possible to describe new phenotypes and study their genetic and molecular mechanisms. This article describes the pathogenetic aspects and genes that cause main and rare syndromic subtypes of EB.
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Affiliation(s)
- Yu Yu Kotalevskaya
- Moscow Regional Research and Clinical Institute, Moscow, Russia Charitable Foundation "BELA. Butterfly Children", Moscow, Russia
| | - V A Stepanov
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
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Vahidnezhad H, Youssefian L, Harvey N, Tavasoli AR, Saeidian AH, Sotoudeh S, Varghaei A, Mahmoudi H, Mansouri P, Mozafari N, Zargari O, Zeinali S, Uitto J. Mutation update: The spectra of PLEC sequence variants and related plectinopathies. Hum Mutat 2022; 43:1706-1731. [PMID: 35815343 PMCID: PMC9771971 DOI: 10.1002/humu.24434] [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: 05/02/2022] [Revised: 06/23/2022] [Accepted: 07/07/2022] [Indexed: 01/24/2023]
Abstract
Plectin, encoded by PLEC, is a cytoskeletal linker of intermediate filaments expressed in many cell types. Plectin consists of three main domains that determine its functionality: the N-terminal domain, the Rod domain, and the C-terminal domain. Molecular defects of PLEC correlating with the functional aspects lead to a group of rare heritable disorders, plectinopathies. These multisystem disorders include an autosomal dominant form of epidermolysis bullosa simplex (EBS-Ogna), limb-girdle muscular dystrophy (LGMD), aplasia cutis congenita (ACC), and an autosomal recessive form of EBS, which may associate with muscular dystrophy (EBS-MD), pyloric atresia (EBS-PA), and/or congenital myasthenic syndrome (EBS-MyS). In this study, genotyping of over 600 Iranian patients with epidermolysis bullosa by next-generation sequencing identified 15 patients with disease-causing PLEC variants. This mutation update analyzes the clinical spectrum of PLEC in our cohort and in the literature and demonstrates the relationship between PLEC genotype and phenotypic manifestations. This study has integrated our seven novel PLEC variants and phenotypic findings with previously published data totaling 116 variants to provide the most complete overview of pathogenic PLEC variants and related disorders.
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Affiliation(s)
- Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
| | - Leila Youssefian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
| | - Nailah Harvey
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
- Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA
| | - Ali Reza Tavasoli
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
- Pediatric Neurology Division, Children’s Medical Center, Pediatric Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Hossein Saeidian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
| | - Soheila Sotoudeh
- Department of Dermatology, Children’s Medical Center, Pediatric Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Aida Varghaei
- Department of Dermatology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Hamidreza Mahmoudi
- Department of Dermatology, Razi Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Parvin Mansouri
- Skin and Stem Cell Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nikoo Mozafari
- Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | | | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
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4
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Epidermolysis Bullosa—A Different Genetic Approach in Correlation with Genetic Heterogeneity. Diagnostics (Basel) 2022; 12:diagnostics12061325. [PMID: 35741135 PMCID: PMC9222206 DOI: 10.3390/diagnostics12061325] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/23/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022] Open
Abstract
Epidermolysis bullosa is a heterogeneous group of rare genetic disorders characterized by mucocutaneous fragility and blister formation after minor friction or trauma. There are four major epidermolysis bullosa types based on the ultrastructural level of tissue cleavage: simplex, junctional, dystrophic, and Kindler epidermolysis bullosa. They are caused by mutations in genes that encode the proteins that are part of the hemidesmosomes and focal adhesion complex. Some of these disorders can be associated with extracutaneous manifestations, which are sometimes fatal. They are inherited in an autosomal recessive or autosomal dominant manner. This review is focused on the phenomena of heterogeneity (locus, allelic, mutational, and clinical) in epidermolysis bullosa, and on the correlation genotype–phenotype.
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Evtushenko NA, Beilin AK, Kosykh AV, Vorotelyak EA, Gurskaya NG. Keratins as an Inflammation Trigger Point in Epidermolysis Bullosa Simplex. Int J Mol Sci 2021; 22:ijms222212446. [PMID: 34830328 PMCID: PMC8624175 DOI: 10.3390/ijms222212446] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 12/21/2022] Open
Abstract
Epidermolysis bullosa simplex (EBS) is a group of inherited keratinopathies that, in most cases, arise due to mutations in keratins and lead to intraepidermal ruptures. The cellular pathology of most EBS subtypes is associated with the fragility of the intermediate filament network, cytolysis of the basal layer of the epidermis, or attenuation of hemidesmosomal/desmosomal components. Mutations in keratins 5/14 or in other genes that encode associated proteins induce structural disarrangements of different strengths depending on their locations in the genes. Keratin aggregates display impaired dynamics of assembly and diminished solubility and appear to be the trigger for endoplasmic reticulum (ER) stress upon being phosphorylated by MAPKs. Global changes in cellular signaling mainly occur in cases of severe dominant EBS mutations. The spectrum of changes initiated by phosphorylation includes the inhibition of proteasome degradation, TNF-α signaling activation, deregulated proliferation, abnormal cell migration, and impaired adherence of keratinocytes. ER stress also leads to the release of proinflammatory danger-associated molecular pattern (DAMP) molecules, which enhance avalanche-like inflammation. Many instances of positive feedback in the course of cellular stress and the development of sterile inflammation led to systemic chronic inflammation in EBS. This highlights the role of keratin in the maintenance of epidermal and immune homeostasis.
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Affiliation(s)
- Nadezhda A. Evtushenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Ostrovityanova 1, 117997 Moscow, Russia; (N.A.E.); (A.K.B.); (A.V.K.)
| | - Arkadii K. Beilin
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Ostrovityanova 1, 117997 Moscow, Russia; (N.A.E.); (A.K.B.); (A.V.K.)
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Vavilova 26, 119334 Moscow, Russia;
| | - Anastasiya V. Kosykh
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Ostrovityanova 1, 117997 Moscow, Russia; (N.A.E.); (A.K.B.); (A.V.K.)
| | - Ekaterina A. Vorotelyak
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Vavilova 26, 119334 Moscow, Russia;
| | - Nadya G. Gurskaya
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Ostrovityanova 1, 117997 Moscow, Russia; (N.A.E.); (A.K.B.); (A.V.K.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Correspondence:
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Kiritsi D, Tsakiris L, Schauer F. Plectin in Skin Fragility Disorders. Cells 2021; 10:cells10102738. [PMID: 34685719 PMCID: PMC8534787 DOI: 10.3390/cells10102738] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022] Open
Abstract
Plectin is a multi-faceted, 500 kDa-large protein, which due to its expression in different isoforms and distinct organs acts diversely as a cytoskeletal crosslinker and signaling scaffold. It functions as a mediator of keratinocyte mechanical stability in the skin, primarily through linking intermediate filaments to hemidesmosomes. Skin fragility may occur through the presence of mutations in the gene encoding for plectin, PLEC, or through the presence of autoantibodies against the molecule. Below, we review the cutaneous manifestations of plectinopathies as well as their systemic involvement in specific disease subtypes. We summarize the known roles of plectin in keratinocytes and fibroblasts and provide an outlook on future perspectives for plectin-associated skin disorders.
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Affiliation(s)
- Dimitra Kiritsi
- Department of Dermatology, Faculty of Medicine, Medical Center-University of Freiburg, 79104 Freiburg, Germany;
- Correspondence:
| | | | - Franziska Schauer
- Department of Dermatology, Faculty of Medicine, Medical Center-University of Freiburg, 79104 Freiburg, Germany;
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7
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Walter MC, Reilich P, Krause S, Hiebeler M, Gehling S, Goebel HH, Schoser B, Abicht A. Congenital myopathy and epidermolysis bullosa due to PLEC variant. Neuromuscul Disord 2021; 31:1212-1217. [PMID: 34702657 DOI: 10.1016/j.nmd.2021.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/29/2021] [Accepted: 09/24/2021] [Indexed: 10/20/2022]
Abstract
We report on an adult Turkish patient with mild myopathy with a fiber-type disproportion and mitochondrial disorganization caused by genetic variants in the plectin gene (PLEC). Molecular genetic panel testing revealed two homozygous variants in PLEC (NM_000445.4): c.8306C>G (p.Pro2769Arg) and c.7506 + 5C>G (p. ?) that were classified as variants of unknown significance (class 3) following ACMG guidelines for variant classification in genetic diagnostics. A thorough reassessment of the patient revealed mild skin blistering (epidermolysis bullosa simplex, EBS). This illustrates the importance of deep phenotyping of neuromuscular patients.
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Affiliation(s)
- Maggie C Walter
- Department of Neurology, Friedrich-Baur-Institute LMU Klinikum, Munich, Germany.
| | - Peter Reilich
- Department of Neurology, Friedrich-Baur-Institute LMU Klinikum, Munich, Germany
| | - Sabine Krause
- Department of Neurology, Friedrich-Baur-Institute LMU Klinikum, Munich, Germany
| | - Miriam Hiebeler
- Department of Neurology, Friedrich-Baur-Institute LMU Klinikum, Munich, Germany
| | | | - Hans H Goebel
- Department of Neuropathology, Charité University, Berlin, and Johannes-Gutenberg University, Mainz, Germany
| | - Benedikt Schoser
- Department of Neurology, Friedrich-Baur-Institute LMU Klinikum, Munich, Germany
| | - Angela Abicht
- Department of Neurology, Friedrich-Baur-Institute LMU Klinikum, Munich, Germany; Medical Genetics Centre, Munich, Germany
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8
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Zrelski MM, Kustermann M, Winter L. Muscle-Related Plectinopathies. Cells 2021; 10:2480. [PMID: 34572129 PMCID: PMC8466646 DOI: 10.3390/cells10092480] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 12/23/2022] Open
Abstract
Plectin is a giant cytoskeletal crosslinker and intermediate filament stabilizing protein. Mutations in the human plectin gene (PLEC) cause several rare diseases that are grouped under the term plectinopathies. The most common disorder is autosomal recessive disease epidermolysis bullosa simplex with muscular dystrophy (EBS-MD), which is characterized by skin blistering and progressive muscle weakness. Besides EBS-MD, PLEC mutations lead to EBS with nail dystrophy, EBS-MD with a myasthenic syndrome, EBS with pyloric atresia, limb-girdle muscular dystrophy type R17, or EBS-Ogna. In this review, we focus on the clinical and pathological manifestations caused by PLEC mutations on skeletal and cardiac muscle. Skeletal muscle biopsies from EBS-MD patients and plectin-deficient mice revealed severe dystrophic features with variation in fiber size, degenerative myofibrillar changes, mitochondrial alterations, and pathological desmin-positive protein aggregates. Ultrastructurally, PLEC mutations lead to a disorganization of myofibrils and sarcomeres, Z- and I-band alterations, autophagic vacuoles and cytoplasmic bodies, and misplaced and degenerating mitochondria. We also summarize a variety of genetically manipulated mouse and cell models, which are either plectin-deficient or that specifically lack a skeletal muscle-expressed plectin isoform. These models are powerful tools to study functional and molecular consequences of PLEC defects and their downstream effects on the skeletal muscle organization.
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Affiliation(s)
| | | | - Lilli Winter
- Center for Anatomy and Cell Biology, Neuromuscular Research Department, Medical University of Vienna, 1090 Vienna, Austria; (M.M.Z.); (M.K.)
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Castañón MJ, Wiche G. Identifying Plectin Isoform Functions through Animal Models. Cells 2021; 10:cells10092453. [PMID: 34572100 PMCID: PMC8468861 DOI: 10.3390/cells10092453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/04/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
Plectin, a high-molecular-weight cytoskeletal linker protein, binds with high affinity to intermediate filaments of all types and connects them to junctional complexes, organelles, and inner membrane systems. In addition, it interacts with actomyosin structures and microtubules. As a multifunctional protein, plectin has been implicated in several multisystemic diseases, the most common of which is epidermolysis bullosa simplex with muscular dystrophy (EBS-MD). A great part of our knowledge about plectin’s functional diversity has been gained through the analysis of a unique collection of transgenic mice that includes a full (null) knockout (KO), several tissue-restricted and isoform-specific KOs, three double KOs, and two knock-in lines. The key molecular features and pathological phenotypes of these mice will be discussed in this review. In summary, the analysis of the different genetic models indicated that a functional plectin is required for the proper function of striated and simple epithelia, cardiac and skeletal muscle, the neuromuscular junction, and the vascular endothelium, recapitulating the symptoms of humans carrying plectin mutations. The plectin-null line showed severe skin and muscle phenotypes reflecting the importance of plectin for hemidesmosome and sarcomere integrity; whereas the ablation of individual isoforms caused a specific phenotype in myofibers, basal keratinocytes, or neurons. Tissue-restricted ablation of plectin rendered the targeted cells less resilient to mechanical stress. Studies based on animal models other than the mouse, such as zebrafish and C. elegans, will be discussed as well.
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Khan FF, Khan N, Rehman S, Ejaz A, Ali U, Erfan M, Ahmed ZM, Naeem M. Identification and Computational Analysis of Novel Pathogenic Variants in Pakistani Families with Diverse Epidermolysis Bullosa Phenotypes. Biomolecules 2021; 11:620. [PMID: 33921969 PMCID: PMC8143555 DOI: 10.3390/biom11050620] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 12/17/2022] Open
Abstract
Epidermolysis bullosa (EB) includes a group of rare gesnodermatoses that result in blistering and erosions of the skin and mucous membranes. Genetically, pathogenic variants in around 20 genes are known to alter the structural and functional integrity of intraepidermal adhesion and dermo-epidermal anchorage, leading to four different types of EB. Here we report the underlying genetic causes of EB phenotypes segregating in seven large consanguineous families, recruited from different regions of Pakistan. Whole exome sequencing, followed by segregation analysis of candidate variants through Sanger sequencing, identified eight pathogenic variants, including three novel (ITGB4: c.1285G>T, and c.3373G>A; PLEC: c.1828A>G) and five previously reported variants (COL7A1: c.6209G>A, and c.1573C>T; FERMT1: c.676insC; LAMA3: c.151insG; LAMB3: c.1705C>T). All identified variants were either absent or had very low frequencies in the control databases. Our in-silico analyses and 3-dimensional (3D) molecular modeling support the deleterious impact of these variants on the encoded proteins. Intriguingly, we report the first case of a recessively inherited form of rare EBS-Ogna associated with a homozygous variant in the PLEC gene. Our study highlights the clinical and genetic diversity of EB in the Pakistani population and expands the mutation spectrum of EB; it could also be useful for prenatal diagnosis and genetic counseling of the affected families.
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Affiliation(s)
- Fehmida F. Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan; (F.F.K.); (N.K.)
| | - Naima Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan; (F.F.K.); (N.K.)
| | - Sakina Rehman
- Laboratory of Neurogenetics and Translational Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Amir Ejaz
- Army Medical College, Rawalpindi 46000, Pakistan;
| | - Uzma Ali
- Department of Dermatology, Capital Hospital, Islamabad 44000, Pakistan;
| | - Muhammad Erfan
- Department of Dermatology, Federal Government Polyclinic Hospital, Islamabad 44000, Pakistan;
| | - Zubair M. Ahmed
- Laboratory of Neurogenetics and Translational Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Muhammad Naeem
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan; (F.F.K.); (N.K.)
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11
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Jacinto JGP, Häfliger IM, Veiga IMB, Drögemüller C, Agerholm JS. A de novo mutation in KRT5 in a crossbred calf with epidermolysis bullosa simplex. J Vet Intern Med 2020; 34:2800-2807. [PMID: 33135329 PMCID: PMC7694802 DOI: 10.1111/jvim.15943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/06/2020] [Accepted: 10/13/2020] [Indexed: 02/03/2023] Open
Abstract
A 6‐day‐old Belgian Blue‐Holstein calf was referred because of a syndrome resembling epidermolysis bullosa simplex (EBS). The clinical phenotype included irregular and differently sized erosions and ulcerations spread over the body, in particular on the limbs and over bone prominences, as well as in the nasal planum and oral mucosa. Blisters were easily induced by rubbing the skin. The skin lesions displayed a clear dermal‐epidermal separation at the level of the basal cell layer. Post mortem examination revealed erosions in the pharynx, proximal esophagus, and rumen. Whole‐genome sequencing revealed a heterozygous disruptive in‐frame deletion variant in KRT5 (c.534_536delCAA). Genotyping of both parents confirmed the variant as de novo mutation. Clinicopathological and genetic findings were consistent with the diagnosis of KRT5‐related EBS providing the second example of a spontaneous mutation causing epidermolysis bullosa in cattle.
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Affiliation(s)
- Joana G P Jacinto
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy.,Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Irene M Häfliger
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Inês M B Veiga
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Jørgen S Agerholm
- Department of Veterinary Clinical Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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Mariath LM, Santin JT, Schuler-Faccini L, Kiszewski AE. Inherited epidermolysis bullosa: update on the clinical and genetic aspects. An Bras Dermatol 2020; 95:551-569. [PMID: 32732072 PMCID: PMC7563003 DOI: 10.1016/j.abd.2020.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/17/2020] [Indexed: 12/14/2022] Open
Abstract
Inherited epidermolysis bullosa is a group of genetic diseases characterized by skin fragility and blistering on the skin and mucous membranes in response to minimal trauma. Epidermolysis bullosa is clinically and genetically very heterogeneous, being classified into four main types according to the layer of skin in which blistering occurs: epidermolysis bullosa simplex (intraepidermal), junctional epidermolysis bullosa (within the lamina lucida of the basement membrane), dystrophic epidermolysis bullosa (below the basement membrane), and Kindler epidermolysis bullosa (mixed skin cleavage pattern). Furthermore, epidermolysis bullosa is stratified into several subtypes, which consider the clinical characteristics, the distribution of the blisters, and the severity of cutaneous and extracutaneous signs. Pathogenic variants in at least 16 genes that encode proteins essential for the integrity and adhesion of skin layers have already been associated with different subtypes of epidermolysis bullosa. The marked heterogeneity of the disease, which includes phenotypes with a broad spectrum of severity and many causal genes, hinders its classification and diagnosis. For this reason, dermatologists and geneticists regularly review and update the classification criteria. This review aimed to update the state of the art on inherited epidermolysis bullosa, with a special focus on the associated clinical and genetic aspects, presenting data from the most recent reclassification consensus, published in 2020.
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Affiliation(s)
- Luiza Monteavaro Mariath
- Postgraduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Juliana Tosetto Santin
- Postgraduate Program in Child and Adolescent Health, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Dermatology Service, Santa Casa de Misericórdia de Porto Alegre/Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
| | | | - Ana Elisa Kiszewski
- Dermatology Service, Santa Casa de Misericórdia de Porto Alegre/Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil; Department of Clinical Medicine, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil; Pediatric Dermatology Unit, Santa Casa de Misericórdia de Porto Alegre/Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil.
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13
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Vallerga CL, Zhang F, Fowdar J, McRae AF, Qi T, Nabais MF, Zhang Q, Kassam I, Henders AK, Wallace L, Montgomery G, Chuang YH, Horvath S, Ritz B, Halliday G, Hickie I, Kwok JB, Pearson J, Pitcher T, Kennedy M, Bentley SR, Silburn PA, Yang J, Wray NR, Lewis SJG, Anderson T, Dalrymple-Alford J, Mellick GD, Visscher PM, Gratten J. Analysis of DNA methylation associates the cystine-glutamate antiporter SLC7A11 with risk of Parkinson's disease. Nat Commun 2020; 11:1238. [PMID: 32144264 PMCID: PMC7060318 DOI: 10.1038/s41467-020-15065-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 02/17/2020] [Indexed: 11/09/2022] Open
Abstract
An improved understanding of etiological mechanisms in Parkinson's disease (PD) is urgently needed because the number of affected individuals is projected to increase rapidly as populations age. We present results from a blood-based methylome-wide association study of PD involving meta-analysis of 229 K CpG probes in 1,132 cases and 999 controls from two independent cohorts. We identify two previously unreported epigenome-wide significant associations with PD, including cg06690548 on chromosome 4. We demonstrate that cg06690548 hypermethylation in PD is associated with down-regulation of the SLC7A11 gene and show this is consistent with an environmental exposure, as opposed to medications or genetic factors with effects on DNA methylation or gene expression. These findings are notable because SLC7A11 codes for a cysteine-glutamate anti-porter regulating levels of the antioxidant glutathione, and it is a known target of the environmental neurotoxin β-methylamino-L-alanine (BMAA). Our study identifies the SLC7A11 gene as a plausible biological target in PD.
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Affiliation(s)
- Costanza L Vallerga
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Futao Zhang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Javed Fowdar
- Griffith Institute for Drug Discovery (GRIDD), Griffith University, Brisbane, Australia
| | - Allan F McRae
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Ting Qi
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Marta F Nabais
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia.,University of Exeter Medical School, Exeter EX2 5DW, Devon, UK
| | - Qian Zhang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Irfahan Kassam
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Anjali K Henders
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Leanne Wallace
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Grant Montgomery
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Yu-Hsuan Chuang
- Department of Epidemiology, Fielding School of Public Health, UCLA, Los Angeles, CA, USA
| | - Steve Horvath
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, USA.,Department of Biostatistics, Fielding School of Public Health, UCLA, Los Angeles, CA, USA
| | - Beate Ritz
- Department of Epidemiology, Fielding School of Public Health, UCLA, Los Angeles, CA, USA.,Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.,Department of Environmental Health, Fielding School of Public Health, UCLA, Los Angeles, CA, USA
| | - Glenda Halliday
- Brain and Mind Centre & Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Ian Hickie
- Brain and Mind Centre & Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - John B Kwok
- Brain and Mind Centre & Faculty of Medicine and Health, The University of Sydney, Sydney, Australia.,School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - John Pearson
- Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Toni Pitcher
- New Zealand Brain Research Institute, Christchurch, New Zealand.,Department of Medicine, University of Otago, Christchurch, New Zealand
| | - Martin Kennedy
- Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Steven R Bentley
- Griffith Institute for Drug Discovery (GRIDD), Griffith University, Brisbane, Australia
| | - Peter A Silburn
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Jian Yang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Naomi R Wray
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Simon J G Lewis
- Brain and Mind Centre & Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Tim Anderson
- New Zealand Brain Research Institute, Christchurch, New Zealand.,Department of Medicine, University of Otago, Christchurch, New Zealand
| | - John Dalrymple-Alford
- New Zealand Brain Research Institute, Christchurch, New Zealand.,Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - George D Mellick
- Griffith Institute for Drug Discovery (GRIDD), Griffith University, Brisbane, Australia
| | - Peter M Visscher
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia. .,Queensland Brain Institute, The University of Queensland, Brisbane, Australia.
| | - Jacob Gratten
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia. .,Mater Research Institute, The University of Queensland, Brisbane, Australia.
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14
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Vahidnezhad H, Youssefian L, Daneshpazhooh M, Mahmoudi H, Kariminejad A, Fischer J, Christiansen J, Schneider H, Guy A, Liu L, McGrath JA, Has C, Uitto J. Biallelic KRT5 mutations in autosomal recessive epidermolysis bullosa simplex, including a complete human keratin 5 "knock-out". Matrix Biol 2019; 83:48-59. [PMID: 31302245 DOI: 10.1016/j.matbio.2019.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 01/06/2023]
Abstract
Epidermolysis bullosa simplex (EBS) is usually inherited as an autosomal dominant disease due to monoallelic gain-of-function mutations in KRT5 or KRT14. Although autosomal recessive forms of EBS have been associated with mutations in at least 10 genes, recessive EBS due to homozygous biallelic KRT5 mutations has not been reported previously; it has been hypothesized that it would result in prenatal lethality. We sought the genetic causes of EB in a cohort of 512 distinct EB families by performing whole exome sequencing (WES) and using an EB-targeting next-generation sequencing (NGS) panel of 21 genes. The pathogenicity and consequences of the mutations were determined by expression profiling and at tissue and ultrastructural levels. Two pathogenic, homozygous missense variants of KRT5 in two patients with generalized EBS and a homozygous null mutation in a patient who died as a neonate from complications of EB were found. The two missense mutations disrupted keratin 5 expression on immunofluorescence microscopy, and the human "knock-out" of KRT5 showed no RNA and protein expression. Collectively, these findings identify biallelic KRT5 mutations with a phenotypic spectrum varying from mild, localized and generalized to perinatal lethal, expanding the genotypic profile of autosomal recessive EBS.
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Affiliation(s)
- Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA; Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA; Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Leila Youssefian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA; Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA; Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Genetics, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Philadelphia, PA, USA
| | - Maryam Daneshpazhooh
- Department of Dermatology, Razi Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamidreza Mahmoudi
- Department of Dermatology, Razi Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Judith Fischer
- Institute of Human Genetics, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Julie Christiansen
- Department of Dermatology and Venereology, Skanes University Hospital, Sweden
| | - Holm Schneider
- Department of Pediatrics, University Hospital Erlangen, Erlangen, Germany
| | - Alyson Guy
- Viapath, St Thomas' Hospital, London, UK
| | - Lu Liu
- Viapath, St Thomas' Hospital, London, UK
| | - John A McGrath
- St John's Institute of Dermatology, King's College London, Guy's Campus, London, UK
| | - Cristina Has
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA; Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA.
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15
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Mariath LM, Santin JT, Frantz JA, Doriqui MJR, Kiszewski AE, Schuler-Faccini L. An overview of the genetic basis of epidermolysis bullosa in Brazil: discovery of novel and recurrent disease-causing variants. Clin Genet 2019; 96:189-198. [PMID: 31001817 DOI: 10.1111/cge.13555] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/01/2019] [Accepted: 04/17/2019] [Indexed: 12/23/2022]
Abstract
Epidermolysis bullosa (EB) is a genodermatosis that encompasses a group of clinically and genetically heterogeneous disorders classified in four major types: EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB) and Kindler syndrome. Our aim was to characterize recurrent and novel mutations associated to EB in a sample of Brazilian patients. Eighty-seven patients (25 EBS, 4 JEB and 58 DEB) were studied. We performed a next-generation sequencing-based multigene panel through ion torrent technology including 11 genes: KRT5, KRT14, PLEC, TGM5, LAMA3, LAMB3, LAMC2, COL17A1, ITGB4, COL7A1, and FERMT1. A total of 72 different pathogenic or likely pathogenic variants were identified, 32 of them are novel. The causal variant was detected in 82 patients (efficiency of 94.3%). Pathogenic variants in the residue 125 of KRT14 were identified in 32% of all EBS patients. In DEB patients, four COL7A1 variants were quite frequent, some of them clustered in specific Brazilian regions. Our study extends the spectrum of known mutations in EB and describes, for the first time, the genetic profile of EB patients from Brazil.
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Affiliation(s)
- Luiza M Mariath
- Postgraduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Juliana T Santin
- Postgraduate Program in Child and Adolescent Health, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Jeanine A Frantz
- Faculty of Medicine, Universidade Regional de Blumenau, Blumenau, Brazil.,Board of Directors, DEBRA Brasil (Epidermolysis Bullosa Research Association of Brazil), Blumenau, Brazil
| | - Maria J R Doriqui
- Section of Medical Genetics, Hospital Infantil Dr. Juvêncio Mattos, São Luís, Brazil
| | - Ana E Kiszewski
- Section of Dermatology, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil.,Section of Pediatric Dermatology, Hospital da Criança Santo Antônio, Irmandade da Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, Brazil
| | - Lavínia Schuler-Faccini
- Postgraduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Department of Genetics, Instituto Nacional de Ciência e Tecnologia de Genética Médica Populacional (INaGeMP), Porto Alegre, Brazil
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16
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Vahidnezhad H, Youssefian L, Saeidian AH, Uitto J. Phenotypic Spectrum of Epidermolysis Bullosa: The Paradigm of Syndromic versus Non-Syndromic Skin Fragility Disorders. J Invest Dermatol 2018; 139:522-527. [PMID: 30393082 DOI: 10.1016/j.jid.2018.10.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/01/2018] [Accepted: 10/03/2018] [Indexed: 11/28/2022]
Abstract
The heritable forms of epidermolysis bullosa (EB), a phenotypically heterogeneous group of skin fragility disorders, is currently associated with mutations in as many as 21 distinct genes. EB is primarily a disorder affecting the epithelial layers of skin and mucous membranes, without extracutaneous manifestations, and thus is nonsyndromic. However, recent demonstrations of skin blistering in multisystem disorders with single gene defects highlight the concept of syndromic EB. Here, we review the phenotypic and genotypic features of syndromic forms of EB to delineate the concept of syndromic versus nonsyndromic skin fragility disorders.
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Affiliation(s)
- Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran; Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Leila Youssefian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Genetics, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Pennsylvania, USA
| | - Amir Hossein Saeidian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Genetics, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Pennsylvania, USA
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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17
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No major role for rare plectin variants in arrhythmogenic right ventricular cardiomyopathy. PLoS One 2018; 13:e0203078. [PMID: 30161220 PMCID: PMC6117038 DOI: 10.1371/journal.pone.0203078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/14/2018] [Indexed: 11/19/2022] Open
Abstract
Aims Likely pathogenic/pathogenic variants in genes encoding desmosomal proteins play an important role in the pathophysiology of arrhythmogenic right ventricular cardiomyopathy (ARVC). However, for a substantial proportion of ARVC patients, the genetic substrate remains unknown. We hypothesized that plectin, a cytolinker protein encoded by the PLEC gene, could play a role in ARVC because it has been proposed to link the desmosomal protein desmoplakin to the cytoskeleton and therefore has a potential function in the desmosomal structure. Methods We screened PLEC in 359 ARVC patients and compared the frequency of rare coding PLEC variants (minor allele frequency [MAF] <0.001) between patients and controls. To assess the frequency of rare variants in the control population, we evaluated the rare coding variants (MAF <0.001) found in the European cohort of the Exome Aggregation Database. We further evaluated plectin localization by immunofluorescence in a subset of patients with and without a PLEC variant. Results Forty ARVC patients carried one or more rare PLEC variants (11%, 40/359). However, rare variants also seem to occur frequently in the control population (18%, 4754/26197 individuals). Nor did we find a difference in the prevalence of rare PLEC variants in ARVC patients with or without a desmosomal likely pathogenic/pathogenic variant (14% versus 8%, respectively). However, immunofluorescence analysis did show decreased plectin junctional localization in myocardial tissue from 5 ARVC patients with PLEC variants. Conclusions Although PLEC has been hypothesized as a promising candidate gene for ARVC, our current study did not show an enrichment of rare PLEC variants in ARVC patients compared to controls and therefore does not support a major role for PLEC in this disorder. Although rare PLEC variants were associated with abnormal localization in cardiac tissue, the confluence of data does not support a role for plectin abnormalities in ARVC development.
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18
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Khani P, Ghazi F, Zekri A, Nasri F, Behrangi E, Aghdam AM, Mirzaei H. Keratins and epidermolysis bullosa simplex. J Cell Physiol 2018; 234:289-297. [PMID: 30078200 DOI: 10.1002/jcp.26898] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 06/12/2018] [Indexed: 11/10/2022]
Abstract
Keratin intermediate filaments play an important role in maintaining the integrity of the skin structure. Understanding the importance of this subject is possible with the investigation of keratin defects in epidermolysis bullosa simplex (EBS). Nowadays, in addition to clinical criteria, new molecular diagnostic methods, such as next generation sequencing, can help to distinguish the subgroups of EBS more precisely. Because the most important and most commonly occurring molecular defects in these patients are the defects of keratins 5 and14 (KRT5 and KRT14), comprehending the nature structure of these proteins and their involved processes can be very effective in understanding the pathophysiology of this disease and providing new and effective therapeutic platforms to treat it. Here, we summarized the various aspects of the presence of KRT5 and KRT14 in the epidermis, their relation to the incidence and severity of EBS phenotypes, and the processes with which these proteins can affect them.
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Affiliation(s)
- Pouria Khani
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Farideh Ghazi
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Ali Zekri
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Farzad Nasri
- Department of Medical Immunology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Elham Behrangi
- Department of Dermatology and Laser Surgery, Clinical Research Center, Rasoul-e-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Arad Mobasher Aghdam
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamed Mirzaei
- Department of Medical Biotechnology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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19
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Abstract
Skin fragility refers to a large group of conditions in which the ability of the skin to provide protection against trivial mechanical trauma is diminished, resulting in the formation of blisters, erosions, wounds, or scars. Acquired and physiological skin fragility is common; genetic disorders are rare but give insight into the molecular mechanisms ensuring skin stability. The paradigm is represented by inherited epidermolysis bullosa. This review is focused on recent advances in understanding the molecular basis of genetic skin fragility, including emerging concepts, controversies, unanswered questions, and opinions of the author. In spite of the advanced knowledge on the genetic causes of skin fragility, the molecular pathology is still expanding. Open questions in understanding the molecular basis of genetic skin fragility are the following: what are the causes of phenotypes which remain genetically unsolved, and what are the molecular modifiers which might explain phenotypic differences among individuals with similar mutations? New mutational mechanisms and new genes have recently been discovered and are briefly described here. Comprehensive next-generation sequencing-based genetic testing improved mutation detection and facilitated the identification of the genetic basis of unclear and new phenotypes. Characterization of the biochemical and cell biological consequences of the genetic variants is challenging and laborious but may represent the basis for personalized therapeutic approaches. Molecular modifiers of skin fragility have been uncovered in particular animal and genetic models but not in larger cohorts of patients. This scientific progress is the basis for revisions of the epidermolysis bullosa classification and for innovative therapeutic approaches designed for this intractable condition.
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Affiliation(s)
- Cristina Has
- Department of Dermatology and Venerology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstrasse 7, DE-79104, Freiburg, Germany
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20
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Thorolfsdottir RB, Sveinbjornsson G, Sulem P, Helgadottir A, Gretarsdottir S, Benonisdottir S, Magnusdottir A, Davidsson OB, Rajamani S, Roden DM, Darbar D, Pedersen TR, Sabatine MS, Jonsdottir I, Arnar DO, Thorsteinsdottir U, Gudbjartsson DF, Holm H, Stefansson K. A Missense Variant in PLEC Increases Risk of Atrial Fibrillation. J Am Coll Cardiol 2017; 70:2157-2168. [PMID: 29050564 PMCID: PMC5704994 DOI: 10.1016/j.jacc.2017.09.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/07/2017] [Accepted: 09/05/2017] [Indexed: 01/19/2023]
Abstract
BACKGROUND Genome-wide association studies (GWAS) have yielded variants at >30 loci that associate with atrial fibrillation (AF), including rare coding mutations in the sarcomere genes MYH6 and MYL4. OBJECTIVES The aim of this study was to search for novel AF associations and in doing so gain insights into the mechanisms whereby variants affect AF risk, using electrocardiogram (ECG) measurements. METHODS The authors performed a GWAS of 14,255 AF cases and 374,939 controls, using whole-genome sequence data from the Icelandic population, and tested novel signals in 2,002 non-Icelandic cases and 12,324 controls. They then tested the AF variants for effect on cardiac electrical function by using measurements in 289,297 ECGs from 62,974 individuals. RESULTS The authors discovered 2 novel AF variants, the intergenic variant rs72700114, between the genes LINC01142 and METTL11B (risk allele frequency = 8.1%; odds ratio [OR]: 1.26; p = 3.1 × 10-18), and the missense variant p.Gly4098Ser in PLEC (frequency = 1.2%; OR: 1.55; p = 8.0 × 10-10), encoding plectin, a cytoskeletal cross-linking protein that contributes to integrity of cardiac tissue. The authors also confirmed 29 reported variants. p.Gly4098Ser in PLEC significantly affects various ECG measurements in the absence of AF. Other AF variants have diverse effects on the conduction system, ranging from none to extensive. CONCLUSIONS The discovery of a missense variant in PLEC affecting AF combined with recent discoveries of variants in the sarcomere genes MYH6 and MYL4 points to an important role of myocardial structure in the pathogenesis of the disease. The diverse associations between AF variants and ECG measurements suggest fundamentally different categories of mechanisms contributing to the development of AF.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Dan M Roden
- Departments of Medicine, Pharmacology, and Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dawood Darbar
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Terje R Pedersen
- Center For Preventive Medicine, Oslo University Hospital and Medical Faculty, University of Oslo, Oslo, Norway
| | - Marc S Sabatine
- TIMI Study Group, Division of Cardiovascular Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Ingileif Jonsdottir
- deCODE genetics/Amgen, Inc., Reykjavik, Iceland; Faculty of Medicine, University of Iceland, Reykjavik, Iceland; Department of Immunology, Landspitali University Hospital, Reykjavik, Iceland
| | - David O Arnar
- deCODE genetics/Amgen, Inc., Reykjavik, Iceland; Faculty of Medicine, University of Iceland, Reykjavik, Iceland; Department of Medicine, Landspitali University Hospital, Reykjavik, Iceland
| | - Unnur Thorsteinsdottir
- deCODE genetics/Amgen, Inc., Reykjavik, Iceland; Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Daniel F Gudbjartsson
- deCODE genetics/Amgen, Inc., Reykjavik, Iceland; School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | - Hilma Holm
- deCODE genetics/Amgen, Inc., Reykjavik, Iceland
| | - Kari Stefansson
- deCODE genetics/Amgen, Inc., Reykjavik, Iceland; Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
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21
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Lin Z, Li S, Feng C, Yang S, Wang H, Ma D, Zhang J, Gou M, Bu D, Zhang T, Kong X, Wang X, Sarig O, Ren Y, Dai L, Liu H, Zhang J, Li F, Hu Y, Padalon-Brauch G, Vodo D, Zhou F, Chen T, Deng H, Sprecher E, Yang Y, Tan X. Stabilizing mutations of KLHL24 ubiquitin ligase cause loss of keratin 14 and human skin fragility. Nat Genet 2016; 48:1508-1516. [DOI: 10.1038/ng.3701] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/26/2016] [Indexed: 12/30/2022]
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22
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A PLEC Isoform Identified in Skin, Muscle, and Heart. J Invest Dermatol 2016; 137:518-522. [PMID: 27769846 DOI: 10.1016/j.jid.2016.09.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 08/08/2016] [Accepted: 09/05/2016] [Indexed: 11/21/2022]
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23
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Abstract
The term epidermolysis bullosa (EB) includes a group of rare genodermatoses characterized by mutational impairment of the structural and functional integrity of intraepidermal adhesion and dermoepidermal anchorage. Clinically, these disorders are marked by increased skin fragility as well as characteristic mechanically inducible blisters on the skin and mucous membranes. Extracutaneous manifestations and their complications in other epithelialized organs render EB a multi-system disease associated with significant morbidity and mortality. Cornerstones of a dynamically changing healthcare structure include precise and early diagnosis; coordinated, multidisciplinary, individually adjusted patient care at specialized centers; optimized symptomatic therapies; and access to research-based, potentially curative therapeutic strategies.
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Affiliation(s)
- Martin Laimer
- Department of Dermatology, Paracelsus Medical University Salzburg, Austria
| | | | - Johann W Bauer
- Department of Dermatology, Paracelsus Medical University Salzburg, Austria
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24
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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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25
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Affiliation(s)
- Martin Laimer
- Universitätsklinik für Dermatologie, Paracelsus Medizinische Privatuniversität Salzburg, Österreich
| | - Christine Prodinger
- Universitätsklinik für Dermatologie, Paracelsus Medizinische Privatuniversität Salzburg, Österreich
| | - Johann W. Bauer
- Universitätsklinik für Dermatologie, Paracelsus Medizinische Privatuniversität Salzburg, Österreich
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26
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Abstract
Muscle fibres are very specialised cells with a complex structure that requires a high level of organisation of the constituent proteins. For muscle contraction to function properly, there is a need for not only sarcomeres, the contractile structures of the muscle fibre, but also costameres. These are supramolecular structures associated with the sarcolemma that allow muscle adhesion to the extracellular matrix. They are composed of protein complexes that interact and whose functions include maintaining cell structure and signal transduction mediated by their constituent proteins. It is important to improve our understanding of these structures, as mutations in various genes that code for costamere proteins cause many types of muscular dystrophy. In this review, we provide a description of costameres detailing each of their constituent proteins, such as dystrophin, dystrobrevin, syntrophin, sarcoglycans, dystroglycans, vinculin, talin, integrins, desmin, plectin, etc. We describe as well the diseases associated with deficiency thereof, providing a general overview of their importance.
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Molecular architecture and function of the hemidesmosome. Cell Tissue Res 2015; 360:529-44. [PMID: 26017636 PMCID: PMC4452579 DOI: 10.1007/s00441-015-2216-6] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 11/03/2014] [Indexed: 01/13/2023]
Abstract
Hemidesmosomes are multiprotein complexes that facilitate the stable adhesion of basal epithelial cells to the underlying basement membrane. The mechanical stability of hemidesmosomes relies on multiple interactions of a few protein components that form a membrane-embedded tightly-ordered complex. The core of this complex is provided by integrin α6β4 and P1a, an isoform of the cytoskeletal linker protein plectin that is specifically associated with hemidesmosomes. Integrin α6β4 binds to the extracellular matrix protein laminin-332, whereas P1a forms a bridge to the cytoplasmic keratin intermediate filament network. Other important components are BPAG1e, the epithelial isoform of bullous pemphigoid antigen 1, BPAG2, a collagen-type transmembrane protein and CD151. Inherited or acquired diseases in which essential components of the hemidesmosome are missing or structurally altered result in tissue fragility and blistering. Modulation of hemidesmosome function is of crucial importance for a variety of biological processes, such as terminal differentiation of basal keratinocytes and keratinocyte migration during wound healing and carcinoma invasion. Here, we review the molecular characteristics of the proteins that make up the hemidesmosome core structure and summarize the current knowledge about how their assembly and turnover are regulated by transcriptional and post-translational mechanisms.
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Ketema M, Secades P, Kreft M, Nahidiazar L, Janssen H, Jalink K, de Pereda JM, Sonnenberg A. The rod domain is not essential for the function of plectin in maintaining tissue integrity. Mol Biol Cell 2015; 26:2402-17. [PMID: 25971800 PMCID: PMC4571296 DOI: 10.1091/mbc.e15-01-0043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/06/2015] [Indexed: 11/22/2022] Open
Abstract
Plectin is a cytoskeletal linker protein that consists of a central rod domain connecting two globular domains. Rodless plectin is able to functionally compensate for the loss of full-length plectin in mice and, like full-length plectin, is able to form dimers. Epidermolysis bullosa simplex associated with late-onset muscular dystrophy (EBS-MD) is an autosomal recessive disorder resulting from mutations in the plectin gene. The majority of these mutations occur within the large exon 31 encoding the central rod domain and leave the production of a low-level rodless plectin splice variant unaffected. To investigate the function of the rod domain, we generated rodless plectin mice through conditional deletion of exon 31. Rodless plectin mice develop normally without signs of skin blistering or muscular dystrophy. Plectin localization and hemidesmosome organization are unaffected in rodless plectin mice. However, superresolution microscopy revealed a closer juxtaposition of the C-terminus of plectin to the integrin β4 subunit in rodless plectin keratinocytes. Wound healing occurred slightly faster in rodless plectin mice than in wild-type mice, and keratinocytes migration was increased in the absence of the rod domain. The faster migration of rodless plectin keratinocytes is not due to altered biochemical properties because, like full-length plectin, rodless plectin is a dimeric protein. Our data demonstrate that rodless plectin can functionally compensate for the loss of full-length plectin in mice. Thus the low expression level of plectin rather than the absence of the rod domain dictates the development of EBS-MD.
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Affiliation(s)
- Mirjam Ketema
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Pablo Secades
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Maaike Kreft
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Leila Nahidiazar
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Hans Janssen
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Kees Jalink
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Jose M de Pereda
- Instituto de Biología Molecular y Celular del Cancer, University of Salamanca-CSIC, E-37007 Salamanca, Spain
| | - Arnoud Sonnenberg
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
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29
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Gostyńska KB, Nijenhuis M, Lemmink H, Pas HH, Pasmooij AMG, Lang KK, Castañón MJ, Wiche G, Jonkman MF. Mutation in exon 1a of PLEC, leading to disruption of plectin isoform 1a, causes autosomal-recessive skin-only epidermolysis bullosa simplex. Hum Mol Genet 2015; 24:3155-62. [PMID: 25712130 DOI: 10.1093/hmg/ddv066] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/13/2015] [Indexed: 01/07/2023] Open
Abstract
PLEC, the gene encoding the cytolinker protein plectin, has eight tissue-specific isoforms in humans, arising by alternate splicing of the first exon. To date, all PLEC mutations that cause epidermolysis bullosa simplex (EBS) were found in exons common to all isoforms. Due to the ubiquitous presence of plectin in mammalian tissues, EBS from recessive plectin mutations is always associated with extracutaneous involvement including muscular dystrophy, pyloric atresia and cardiomyopathy. We studied a consanguineous family with sisters having isolated blistering suggesting EBS. Skin disease started with foot blisters at walking age and became generalized at puberty while sparing mucous membranes. DNA sequencing revealed a homozygous nonsense mutation (c.46C>T; p.Arg16X) in the first exon of the plectin variant encoding plectin isoform 1a (P1a). Immunofluorescence antigen mapping, transmission electron microscopy, western blot analysis and qRT-PCR were performed on patient skin and cultured keratinocytes, control myocardium and striated muscle samples. We found hypoplastic hemidesmosomes and intra-epidermal 'pseudo-junctional' cleavage fitting EBS. Screening for cardiomyopathy and muscle dystrophy showed no abnormalities. We report the first cases of autosomal-recessive EBS from P1a deficiency affecting skin, while mucous membranes, heart and muscle are spared. The dominant expression of the P1a isoform in epidermal basal cell layer and cultured keratinocytes suggests that mutations in the first exon of isoform 1a cause skin-only EBS without extracutaneous involvement. Our study characterizes yet another of the eight isoforms of plectin and adds a tissue-specific phenotype to the spectrum of 'plectinopathies' produced by mutations of unique first exons of this gene.
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Affiliation(s)
| | | | - Henny Lemmink
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | | | | | - Maria J Castañón
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, Vienna, Austria
| | - Gerhard Wiche
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, Vienna, Austria
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30
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Molecular architecture and function of the hemidesmosome. Cell Tissue Res 2014; 360:363-78. [PMID: 25487405 PMCID: PMC4544487 DOI: 10.1007/s00441-014-2061-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 11/03/2014] [Indexed: 01/07/2023]
Abstract
Hemidesmosomes are multiprotein complexes that facilitate the stable adhesion of basal epithelial cells to the underlying basement membrane. The mechanical stability of hemidesmosomes relies on multiple interactions of a few protein components that form a membrane-embedded tightly-ordered complex. The core of this complex is provided by integrin α6β4 and P1a, an isoform of the cytoskeletal linker protein plectin that is specifically associated with hemidesmosomes. Integrin α6β4 binds to the extracellular matrix protein laminin-332, whereas P1a forms a bridge to the cytoplasmic keratin intermediate filament network. Other important components are BPAG1e, the epithelial isoform of bullous pemphigoid antigen 1, BPAG2, a collagen-type transmembrane protein and CD151. Inherited or acquired diseases in which essential components of the hemidesmosome are missing or structurally altered result in tissue fragility and blistering. Modulation of hemidesmosome function is of crucial importance for a variety of biological processes, such as terminal differentiation of basal keratinocytes and keratinocyte migration during wound healing and carcinoma invasion. Here, we review the molecular characteristics of the proteins that make up the hemidesmosome core structure and summarize the current knowledge about how their assembly and turnover are regulated by transcriptional and post-translational mechanisms.
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31
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Plectin-related skin diseases. J Dermatol Sci 2014; 77:139-45. [PMID: 25530118 DOI: 10.1016/j.jdermsci.2014.11.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/05/2014] [Accepted: 11/12/2014] [Indexed: 12/20/2022]
Abstract
Plectin has been characterized as a linker protein that is expressed in many cell types and is distinctive in various isoforms in the N-terminus and around the rod domain due to complicated alternative splicing of PLEC, the gene encoding plectin. Plectin deficiency causes autosomal recessive epidermolysis bullosa simplex (EBS) with involvement of the skin and other organs, such as muscle and gastrointestinal tract, depending on the expression pattern of the defective protein. In addition, a point mutation in the rod domain of plectin leads to autosomal dominant EBS, called as EBS-Ogna. Plectin can be targeted by circulating autoantibodies in subepidermal autoimmune blistering diseases. This review summarizes plectin-related skin diseases, from congenital to autoimmune disorders.
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32
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Medeiros GX, Riet-Correa F. Epidermolysis bullosa in animals: a review. Vet Dermatol 2014; 26:3-13, e1-2. [PMID: 25354580 DOI: 10.1111/vde.12176] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2014] [Indexed: 11/30/2022]
Abstract
Epidermolysis bullosa (EB) is a hereditary mechanobullous disease of animals and humans, characterized by an extreme fragility of the skin and mucous membranes. The main feature of EB in humans and animals is the formation of blisters and erosions in response to minor mechanical trauma. Epidermolysis bullosa is caused by mutations in the genes that code for structural proteins of the cytoskeleton of the basal keratinocytes or of the basement membrane zone. Based on the ultrastructural levels of tissue separation, EB is divided into the following three broad categories: epidermolysis bullosa simplex, junctional epidermolysis bullosa and dystrophic epidermolysis bullosa. Human types of EB are divided into several subtypes based on their ultrastructural changes and the mode of inheritance; subtypes are not fully established in animals. In humans, it is estimated that EB affects one in 17,000 live births; the frequency of EB in different animals species is not known. In all animal species, except in buffalo with epidermolysis bullosa simplex, multifocal ulcers are observed on the gums, hard and soft palates, mucosa of the lips, cheek mucosa and dorsum of the tongue. Dystrophic or absent nails, a frequent sign seen in human patients with EB, corresponds to the deformities and sloughing of the hooves in ungulates and to dystrophy or atrophy of the claws in dogs and cats. This review covers aspects of the molecular biology, diagnosis, classification, clinical signs and pathology of EB reported in animals.
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Affiliation(s)
- Gildenor X Medeiros
- Postgraduate Program in Veterinary Medicine, Veterinary Hospital, Federal University of Campina Grande, Patos, Paraíba, CEP 58708-110, Brazil
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33
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Vellarikkal SK, Patowary A, Singh M, Kumari R, Faruq M, Master DC, Sivasubbu S, Scaria V. Exome sequencing reveals a novel mutation, p.L325H, in the KRT5 gene associated with autosomal dominant Epidermolysis Bullosa Simplex Koebner type in a large family from western India. Hum Genome Var 2014; 1:14007. [PMID: 27081501 PMCID: PMC4785511 DOI: 10.1038/hgv.2014.7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/14/2014] [Accepted: 06/30/2014] [Indexed: 11/25/2022] Open
Abstract
We report a large, non-consanguineous family comprising five generations of individuals residing in Gujarat, India affected with localized Epidermolysis Bullosa Simplex (EBS) Koebner type. We analyzed 14 individuals including 9 affected individuals from this family. Exome sequencing in two cases suggested a novel non-synonymous variation, p.L325H, in the KRT5 gene. The present analysis also reports the first causative mutation of EBS Koebner type from India.
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Affiliation(s)
- Shamsudheen K Vellarikkal
- Genomics and Molecular Medicine Unit, CSIR Institute of Genomics and Integrative Biology, Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India
| | - Ashok Patowary
- Genomics and Molecular Medicine Unit, CSIR Institute of Genomics and Integrative Biology , Delhi, India
| | - Meghna Singh
- Genomics and Molecular Medicine Unit, CSIR Institute of Genomics and Integrative Biology, Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India
| | - Renu Kumari
- Genomics and Molecular Medicine Unit, CSIR Institute of Genomics and Integrative Biology, Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine Unit, CSIR Institute of Genomics and Integrative Biology, Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India
| | - Dilip C Master
- Department of Anatomy, Government Medical College , Baroda, India
| | - Sridhar Sivasubbu
- Genomics and Molecular Medicine Unit, CSIR Institute of Genomics and Integrative Biology, Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India
| | - Vinod Scaria
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India; GN Ramachandran Knowledge Center for Genome Informatics, CSIR Institute of Genomics and Integrative Biology, Delhi, India
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34
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Abstract
Genetic skin fragility manifests with diminished resistance of the skin and mucous membranes to external mechanical forces and with skin blistering, erosions, and painful wounds as clinical features. Skin fragility disorders, collectively called epidermolysis bullosa, are caused by mutations in 18 distinct genes that encode proteins involved in epidermal integrity and dermal-epidermal adhesion. The genetic spectrum, along with environmental and genetic modifiers, creates a large number of clinical phenotypes, spanning from minor localized lesions to severe generalized blistering, secondary skin cancer, or early demise resulting from extensive loss of the epidermis. Laboratory investigations of skin fragility have greatly augmented our understanding of genotype-phenotype correlations in epidermolysis bullosa and have also advanced skin biology in general. Current translational research concentrates on the development of biologically valid treatments with therapeutic genes, cells, proteins, or small-molecule compounds in preclinical settings or human pilot trials.
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Affiliation(s)
- Cristina Has
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg 79104, Germany;
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35
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Kern JS, Has C. Update on diagnosis and therapy of inherited epidermolysis bullosa. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/17469872.3.6.721] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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36
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Bolling MC, Jongbloed JDH, Boven LG, Diercks GFH, Smith FJD, Irwin McLean WH, Jonkman MF. Plectin mutations underlie epidermolysis bullosa simplex in 8% of patients. J Invest Dermatol 2014; 134:273-276. [PMID: 23774525 DOI: 10.1038/jid.2013.277] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Marieke C Bolling
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan D H Jongbloed
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ludolf G Boven
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Gilles F H Diercks
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Frances J D Smith
- Epithelial Genetics Group, Division of Molecular Medicine, Colleges of Life Sciences and Medicine, Dentistry and Nursing, University of Dundee, Dundee, UK
| | - W H Irwin McLean
- Epithelial Genetics Group, Division of Molecular Medicine, Colleges of Life Sciences and Medicine, Dentistry and Nursing, University of Dundee, Dundee, UK
| | - Marcel F Jonkman
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
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37
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Bouameur JE, Favre B, Borradori L. Plakins, a versatile family of cytolinkers: roles in skin integrity and in human diseases. J Invest Dermatol 2013; 134:885-894. [PMID: 24352042 DOI: 10.1038/jid.2013.498] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/16/2013] [Accepted: 10/25/2013] [Indexed: 11/09/2022]
Abstract
The plakin family consists of giant proteins involved in the cross-linking and organization of the cytoskeleton and adhesion complexes. They further modulate several fundamental biological processes, such as cell adhesion, migration, and polarization or signaling pathways. Inherited and acquired defects of plakins in humans and in animal models potentially lead to dramatic manifestations in the skin, striated muscles, and/or nervous system. These observations unequivocally demonstrate the key role of plakins in the maintenance of tissue integrity. Here we review the characteristics of the mammalian plakin members BPAG1 (bullous pemphigoid antigen 1), desmoplakin, plectin, envoplakin, epiplakin, MACF1 (microtubule-actin cross-linking factor 1), and periplakin, highlighting their role in skin homeostasis and diseases.
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Affiliation(s)
- Jamal-Eddine Bouameur
- Departments of Dermatology and Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Bertrand Favre
- Departments of Dermatology and Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland.
| | - Luca Borradori
- Departments of Dermatology and Clinical Research, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
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38
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Castañón MJ, Walko G, Winter L, Wiche G. Plectin-intermediate filament partnership in skin, skeletal muscle, and peripheral nerve. Histochem Cell Biol 2013; 140:33-53. [PMID: 23748243 PMCID: PMC3695321 DOI: 10.1007/s00418-013-1102-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2013] [Indexed: 01/13/2023]
Abstract
Plectin is a large, 500-kDa, intermediate filament (IF)-associated protein. It acts as a cytoskeletal crosslinker and signaling scaffold, affecting mechanical as well as dynamic properties of the cytoskeleton. As a member of the plakin family of cytolinker proteins, plectin has a multidomain structure that is responsible for its vast binding portfolio. It not only binds to all types of IFs, actin filaments and microtubules, but also to transmembrane receptors, proteins of the subplasma membrane protein skeleton, components of the nuclear envelope, and several kinases with known roles in migration, proliferation, and energy metabolism of cells. Due to alternative splicing, plectin is expressed as various isoforms with differing N-terminal heads that dictate their differential subcellular targeting. Through specific interactions with other proteins at their target sites and their ability to bind to all types of IFs, plectin molecules provide strategically located IF anchorage sites within the cytoplasm of cells. In this review, we will present an overview of the structural features and functional properties of plectin and discuss recent progress in defining the role of its isoforms in stress-prone tissues and the implicated diseases, with focus on skin, skeletal muscle, and Schwann cells of peripheral nerve.
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Affiliation(s)
- Maria J. Castañón
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, 1030 Vienna, Austria
| | - Gernot Walko
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, 1030 Vienna, Austria
- Present Address: Centre for Stem Cells and Regenerative Medicine, King’s College London School of Medicine, 28th Floor, Tower Wing, Guy’s Hospital, Great Maze Pond, London, SE1 9RT UK
| | - Lilli Winter
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, 1030 Vienna, Austria
- Present Address: Institute of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany
| | - Gerhard Wiche
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, 1030 Vienna, Austria
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39
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Winter L, Wiche G. The many faces of plectin and plectinopathies: pathology and mechanisms. Acta Neuropathol 2013; 125:77-93. [PMID: 22864774 DOI: 10.1007/s00401-012-1026-0] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 07/12/2012] [Accepted: 07/23/2012] [Indexed: 12/20/2022]
Abstract
Plectin, a giant multifunctional cytolinker protein, plays a crucial role in stabilizing and orchestrating intermediate filament networks in cells. Mutations in the human plectin gene result in multiple diseases manifesting with muscular dystrophy, skin blistering, and signs of neuropathy. The most common disease caused by plectin deficiency is epidermolysis bullosa simplex (EBS)-MD, a rare autosomal-recessive skin blistering disorder with late-onset muscular dystrophy. EBS-MD patients and plectin-deficient mice display pathologic desmin-positive protein aggregates, degenerated myofibrils, and mitochondrial abnormalities, the hallmarks of myofibrillar myopathies. In addition to EBS-MD, plectin mutations have been shown to cause EBS-MD with a myasthenic syndrome, limb-girdle muscular dystrophy type 2Q, EBS with pyloric atresia, and EBS-Ogna. This review focuses on clinical and pathological manifestations of these plectinopathies. It addresses especially plectin's role in skeletal muscle, where a loss of muscle fiber integrity and profound changes of myofiber cytoarchitecture are observed in its absence. Furthermore, the highly complex genetic and molecular structure of plectin is discussed; a high number of differentially spliced exons give rise to a variety of different isoforms, which fulfill distinct functions in different cell types and tissues. Plectin's abilities to act as a dynamic organizer of intermediate filament networks and to interact with a multitude of different interaction partners are the basis for its function as a scaffolding platform for proteins involved in signaling. Finally, the article addresses a series of genetically manipulated mouse lines that were generated to serve as powerful models to study functional and molecular consequences of plectin gene defects.
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Affiliation(s)
- Lilli Winter
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9, 1030 Vienna, Austria
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40
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Abstract
The progress of molecular genetics helps clinicians to prove or exclude a suspected diagnosis for a vast and yet increasing number of genodermatoses. This leads to precise genetic counselling, prenatal diagnosis and preimplantation genetic haplotyping for many inherited skin conditions. It is also helpful in such occasions as phenocopy, late onset and incomplete penetrance, uniparental disomy, mitochondrial inheritance and pigmentary mosaicism. Molecular methods of two genodermatoses are explained in detail, i.e. genodermatoses with skin fragility and neurofibromatosis type 1.
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Affiliation(s)
- Vesarat Wessagowit
- Molecular Genetics Laboratory, The Institute of Dermatology, Bangkok, Thailand.
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41
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42
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Targeted proteolysis of plectin isoform 1a accounts for hemidesmosome dysfunction in mice mimicking the dominant skin blistering disease EBS-Ogna. PLoS Genet 2011; 7:e1002396. [PMID: 22144912 PMCID: PMC3228830 DOI: 10.1371/journal.pgen.1002396] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 10/10/2011] [Indexed: 01/09/2023] Open
Abstract
Autosomal recessive mutations in the cytolinker protein plectin account for the multisystem disorders epidermolysis bullosa simplex (EBS) associated with muscular dystrophy (EBS-MD), pyloric atresia (EBS-PA), and congenital myasthenia (EBS-CMS). In contrast, a dominant missense mutation leads to the disease EBS-Ogna, manifesting exclusively as skin fragility. We have exploited this trait to study the molecular basis of hemidesmosome failure in EBS-Ogna and to reveal the contribution of plectin to hemidesmosome homeostasis. We generated EBS-Ogna knock-in mice mimicking the human phenotype and show that blistering reflects insufficient protein levels of the hemidesmosome-associated plectin isoform 1a. We found that plectin 1a, in contrast to plectin 1c, the major isoform expressed in epidermal keratinocytes, is proteolytically degraded, supporting the notion that degradation of hemidesmosome-anchored plectin is spatially controlled. Using recombinant proteins, we show that the mutation renders plectin's 190-nm-long coiled-coil rod domain more vulnerable to cleavage by calpains and other proteases activated in the epidermis but not in skeletal muscle. Accordingly, treatment of cultured EBS-Ogna keratinocytes as well as of EBS-Ogna mouse skin with calpain inhibitors resulted in increased plectin 1a protein expression levels. Moreover, we report that plectin's rod domain forms dimeric structures that can further associate laterally into remarkably stable (paracrystalline) polymers. We propose focal self-association of plectin molecules as a novel mechanism contributing to hemidesmosome homeostasis and stabilization. Hemidesmosomes are specialized protein complexes that promote anchorage of the basal keratinocyte cell layer of the epidermis to the underlying dermis. They provide tissue integrity and resistance to mechanical forces. When hemidesmosomes do not function properly, skin blistering ensues in response to mechanical trauma. Plectin is an essential component of hemidesmosomes. Humans carrying recessive mutations in the plectin gene most frequently develop multisystem disorders, where in addition to skin other tissues are also affected. However, there is a unique dominant plectin mutation, which leads to the disease epidermolysis bullosa simplex Ogna (EBS-Ogna), affecting skin exclusively. Because of that, EBS-Ogna is an exceptional system to study the contribution of plectin to hemidesmosome function. We have generated an EBS-Ogna mouse model that mimics the human disease. Using this model, we have learned that selective degradation of hemidesmosome-associated plectin isoform 1a by proteases activated specifically in keratinocytes results in reduced numbers and dysfunction of hemidesmosomes. In contrast, plectin-1c, another plectin isoform expressed in keratinocytes, is not degraded. Moreover, we find that plectin dimers can oligomerize via their long coiled-coil rod domain, a process likely to be instrumental in maintenance of hemidesmosome integrity. These findings highlight the importance of plectin-1a for hemidesmosome function.
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Yiu EM, Klausegger A, Waddell LB, Grasern N, Lloyd L, Tran K, North KN, Bauer JW, McKelvie P, Chow C, Ryan MM, Murrell DF. Epidermolysis bullosa with late-onset muscular dystrophy and plectin deficiency. Muscle Nerve 2011; 44:135-41. [DOI: 10.1002/mus.22076] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bolling MC, Lemmink HH, Jansen GHL, Jonkman MF. Mutations in KRT5 and KRT14 cause epidermolysis bullosa simplex in 75% of the patients. Br J Dermatol 2011; 164:637-44. [PMID: 21375516 DOI: 10.1111/j.1365-2133.2010.10146.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Epidermolysis bullosa simplex (EBS) is a mechanobullous genodermatosis that may be caused by mutations in the genes KRT5 and KRT14 encoding the basal epidermal keratins 5 (K5) and 14 (K14). Three main clinical subtypes of EBS exist, differing in onset, distribution and severity of skin blistering. Previous reports of KRT5 and KRT14 mutations suggest a correlation between the location of the mutation and the severity of the associated EBS phenotype. OBJECTIVES The prevalence of KRT5/KRT14 mutations and the genotype-phenotype correlation in the largest tissue-confirmed EBS population is investigated. METHODS KRT5 and KRT14 genomic DNA and cDNA sequences of 76 clinically well-defined unrelated EBS probands were amplified and then subjected to direct sequencing and product length analysis. Immunofluorescence microscopy on patients' skin biopsies with antibodies against K5 and K14 was performed to study protein expression. RESULTS In 57 of 76 (75%) probands 41 different KRT5 and KRT14 mutations were identified, of which 12 were novel. Mutations affecting the highly conserved helix boundary motifs of the rod domains of K5 and K14, and the K14 helix initiation motif in particular, were associated with the severest, EBS Dowling-Meara, phenotype. In 21 EBS probands (37%) the mutation was de novo. In 19 probands (25%) KRT5 or KRT14 mutations were excluded. CONCLUSIONS The phenotype-genotype correlation observed in this large EBS population underscores the importance of helix boundary motifs for keratin assembly. Only three-quarters of biopsy-confirmed EBS probands have KRT5 or KRT14 mutations, indicating genetic heterogeneity in EBS. Alternative gene candidates are discussed.
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Affiliation(s)
- M C Bolling
- Center for Blistering Diseases, Department of Dermatology, University Medical Center Groningen, the Netherlands.
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D'Alessandro M, Coats SE, Jonkman MF, Jonkmann MF, Leigh IM, Lane EB. Keratin 14-null cells as a model to test the efficacy of gene therapy approaches in epithelial cells. J Invest Dermatol 2011; 131:1412-9. [PMID: 21326298 DOI: 10.1038/jid.2011.19] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Skin fragility disorders caused by keratin mutations are incurable, and a better understanding of their etiology is needed to find new ways to improve and treat these conditions. The best-studied skin fragility disorder is epidermolysis bullosa simplex (EBS), an autosomal dominant condition caused by mutations in keratin 5 (K5) or K14. To analyze disease mechanisms and develop gene therapy strategies, we have used keratinocyte cell lines derived from EBS patients as model systems. Here, we describe two cell lines established from EBS patients with K14-null mutations. We analyze the responses of these cells to stress assays previously shown to discriminate between wild-type and keratin-mutant keratinocytes, to directly evaluate the efficacy of rescuing K14-null cells by supplementation with wild-type K14 complementary DNA (cDNA). The K14-null cells show elevated levels of stress correlating with reduced normal keratin function. By transfecting wild-type K14 into these cells, we demonstrate "proof of principle" that an add-back approach can significantly rescue the normal keratinocyte behavior profile. These K14-null cell lines provide a disease model for studying the effects of keratin ablation in EBS patients and to test the efficacy of gene add-back and other therapy approaches in keratinocytes.
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Affiliation(s)
- Mariella D'Alessandro
- CR UK Cell Structure Research Group, Division of Molecular Medicine, College of Life Sciences, University of Dundee, Dundee, UK.
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Chang EH, Pezzulo AA, Zabner J. Do cell junction protein mutations cause an airway phenotype in mice or humans? Am J Respir Cell Mol Biol 2011; 45:202-20. [PMID: 21297078 DOI: 10.1165/rcmb.2010-0498tr] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Cell junction proteins connect epithelial cells to each other and to the basement membrane. Genetic mutations of these proteins can cause alterations in some epithelia leading to varied phenotypes such as deafness, renal disease, skin disorders, and cancer. This review examines if genetic mutations in these proteins affect the function of lung airway epithelia. We review cell junction proteins with examples of disease mutation phenotypes in humans and in mouse knockout models. We also review which of these genes are expressed in airway epithelium by microarray expression profiling and immunocytochemistry. Last, we present a comprehensive literature review to find the lung phenotype when cell junction and adhesion genes are mutated or subject to targeted deletion. We found that in murine models, targeted deletion of cell junction and adhesion genes rarely result in a lung phenotype. Moreover, mutations in these genes in humans have no obvious lung phenotype. Our research suggests that simply because a cell junction or adhesion protein is expressed in an organ does not imply that it will exhibit a drastic phenotype when mutated. One explanation is that because a functioning lung is critical to survival, redundancy in the system is expected. Therefore mutations in a single gene might be compensated by a related function of a similar gene product. Further studies in human and animal models will help us understand the overlap in the function of cell junction gene products. Finally, it is possible that the human lung phenotype is subtle and has not yet been described.
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Affiliation(s)
- Eugene H Chang
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, USA
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Natsuga K, Nishie W, Akiyama M, Nakamura H, Shinkuma S, McMillan JR, Nagasaki A, Has C, Ouchi T, Ishiko A, Hirako Y, Owaribe K, Sawamura D, Bruckner-Tuderman L, Shimizu H. Plectin expression patterns determine two distinct subtypes of epidermolysis bullosa simplex. Hum Mutat 2010; 31:308-16. [PMID: 20052759 DOI: 10.1002/humu.21189] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Plectin is a cytoskeletal linker protein that has a dumbbell-like structure with a long central rod and N- and C-terminal globular domains. Mutations in the gene encoding plectin (PLEC1) cause two distinct autosomal recessive subtypes of epidermolysis bullosa (EB): EB simplex with muscular dystrophy (EBS-MD), and EB simplex with pyloric atresia (EBS-PA). Here, we demonstrate that normal human fibroblasts express two different plectin isoforms including full-length and rodless forms of plectin. We performed detailed analysis of plectin expression patterns in six EBS-MD and three EBS-PA patients. In EBS-PA, expression of all plectin domains was found to be markedly attenuated or completely lost; in EBS-MD, the expression of the N- and C-terminal domains of plectin remained detectable, although the expression of rod domains was absent or markedly reduced. Our data suggest that loss of the full-length plectin isoform with residual expression of the rodless plectin isoform leads to EBS-MD, and that complete loss or marked attenuation of full-length and rodless plectin expression underlies the more severe EBS-PA phenotype. These results also clearly account for the majority of EBS-MD PLEC1 mutation restriction within the large exon 31 that encodes the plectin rod domain, whereas EBS-PA PLEC1 mutations are generally outside exon 31.
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Affiliation(s)
- Ken Natsuga
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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Cepeda-Valdés R, Pohla-Gubo G, Borbolla-Escoboza J, Barboza-Quintana O, Ancer-Rodríguez J, Hintner H, Salas-Alanis J. Mapeo por inmunofluorescencia para el diagnóstico de epidermólisis ampollosa congénita. ACTAS DERMO-SIFILIOGRAFICAS 2010. [DOI: 10.1016/j.ad.2010.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Chiavérini C, Charlesworth A, Meneguzzi G, Lacour JP, Ortonne JP. Epidermolysis bullosa simplex with muscular dystrophy. Dermatol Clin 2010; 28:245-55, viii. [PMID: 20447487 DOI: 10.1016/j.det.2010.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Epidermolysis bullosa simplex (EBS) is an inherited skin disorder characterized by separation of the epidermis from the underlying dermis, with the cleavage plane lying within the basal-cell layer of the epithelium. The major clinical subtypes of EBS have a dominant inheritance and have been associated with genetic defects in specific domains of keratins K5 and K14 that result in abnormal organization of the keratin network and cell disruption. Autosomal recessive forms of EBS associated with extracutaneous manifestations, such as muscular dystrophy (MIM 226670) or pyloric atresia (MIM 612138), have been linked to genetic mutations in the gene for plectin (PLEC). PLEC mutations have also been found in 2 families with the rare dominant Ogna form of EBS. This article reviews current knowledge on EBS.
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Affiliation(s)
- C Chiavérini
- French Reference Center of Hereditary Epidermolysis Bullosa, Nice, France.
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Pohla-Gubo G, Cepeda-Valdes R, Hintner H. Immunofluorescence mapping for the diagnosis of epidermolysis bullosa. Dermatol Clin 2010; 28:201-10, vii. [PMID: 20447482 DOI: 10.1016/j.det.2009.12.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Immunofluorescence mapping is based on the detection of structural proteins of keratinocytes or of the dermo-epidermal junction using specific poly- or monoclonal antibodies. Through this method, the level of split formation can be determined by investigating the location of a given antigen in a natural or induced blister. This method also allows testing for the normal expression, reduction or absence of various structural proteins depending on the antibodies used. It has widely replaced transmission electron microscopy and is used as the initial laboratory test to prove the clinical diagnosis of epidermolysis bullosa.
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Affiliation(s)
- Gabriela Pohla-Gubo
- Department of Dermatology, Paracelsus Medical University, Salzburg, Austria.
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