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Sproule TJ, Wilpan RY, Low BE, Silva KA, Reyon D, Joung JK, Wiles MV, Roopenian DC, Sundberg JP. Functional analysis of Collagen 17a1: A genetic modifier of junctional epidermolysis bullosa in mice. PLoS One 2023; 18:e0292456. [PMID: 37796769 PMCID: PMC10553217 DOI: 10.1371/journal.pone.0292456] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/20/2023] [Indexed: 10/07/2023] Open
Abstract
Previous work strongly implicated Collagen 17a1 (Col17a1) as a potent genetic modifier of junctional epidermolysis bullosa (JEB) caused by a hypomorphic mutation (Lamc2jeb) in mice. The importance of the noncollagenous domain (NC4) of COLXVII was suggested by use of a congenic reduction approach that restricted the modifier effect to 2-3 neighboring amino acid changes in that domain. The current study utilizes TALEN and CRISPR/Cas9 induced amino acid replacements and in-frame indels nested to NC4 to further investigate the role of this and adjoining COLXVII domains both as modifiers and primary risk effectors. We confirm the importance of COLXVI AA 1275 S/G and 1277 N/S substitutions and utilize small nested indels to show that subtle changes in this microdomain attenuate JEB. We further show that large in-frame indels removing up to 1482 bp and 169 AA of NC6 through NC1 domains are surprisingly disease free on their own but can be very potent modifiers of Lamc2jeb/jeb JEB. Together these studies exploiting gene editing to functionally dissect the Col17a1 modifier demonstrate the importance of epistatic interactions between a primary disease-causing mutation in one gene and innocuous 'healthy' alleles in other genes.
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Affiliation(s)
| | - Robert Y. Wilpan
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Benjamin E. Low
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Deepak Reyon
- Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Center for Cancer Research, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - J. Keith Joung
- Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Center for Cancer Research, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael V. Wiles
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - John P. Sundberg
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- Department of Dermatology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
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2
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Sproule TJ, Philip VM, Chaudhry NA, Roopenian DC, Sundberg JP. Seven naturally variant loci serve as genetic modifiers of Lamc2jeb induced non-Herlitz junctional Epidermolysis Bullosa in mice. PLoS One 2023; 18:e0288263. [PMID: 37437067 PMCID: PMC10337971 DOI: 10.1371/journal.pone.0288263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/22/2023] [Indexed: 07/14/2023] Open
Abstract
Epidermolysis Bullosa (EB) is a group of rare genetic disorders that compromise the structural integrity of the skin such that blisters and subsequent erosions occur after minor trauma. While primary genetic risk of all subforms of EB adhere to Mendelian patterns of inheritance, their clinical presentations and severities can vary greatly, implying genetic modifiers. The Lamc2jeb mouse model of non-Herlitz junctional EB (JEB-nH) demonstrated that genetic modifiers can contribute substantially to the phenotypic variability of JEB and likely other forms of EB. The innocuous changes in an 'EB related gene', Col17a1, have shown it to be a dominant modifier of Lamc2jeb. This work identifies six additional Quantitative Trait Loci (QTL) that modify disease in Lamc2jeb/jeb mice. Three QTL include other known 'EB related genes', with the strongest modifier effect mapping to a region including the epidermal hemi-desmosomal structural gene dystonin (Dst-e/Bpag1-e). Three other QTL map to intervals devoid of known EB-associated genes. Of these, one contains the nuclear receptor coactivator Ppargc1a as its primary candidate and the others contain related genes Pparg and Igf1, suggesting modifier pathways. These results, demonstrating the potent disease modifying effects of normally innocuous genetic variants, greatly expand the landscape of genetic modifiers of EB and therapeutic approaches that may be applied.
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Affiliation(s)
| | - Vivek M. Philip
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | | | - John P. Sundberg
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- Department of Dermatology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
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3
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Nyström A, Kiritsi D. Transmembrane collagens-Unexplored mediators of epidermal-dermal communication and tissue homeostasis. Exp Dermatol 2020; 30:10-16. [PMID: 32869371 DOI: 10.1111/exd.14180] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 08/11/2020] [Accepted: 08/24/2020] [Indexed: 12/26/2022]
Abstract
Tissue homeostasis is maintained through constant, dynamic and heterogeneous communication between cells and their microenvironment. Proteins that are at the same time active at the intracellular, cell periphery and deeper extracellular levels possess the ability to, on the individual molecular level, influence the cells and their microenvironment in a bidirectional manner. The transmembrane collagens are a family of such proteins, which are of notable interest for tissue development and homeostasis. In skin, expression of all transmembrane collagens has been reported and deficiency of transmembrane collagen XVII manifests with distinct skin phenotypes. Nevertheless, transmembrane collagens in skin remain understudied despite the association of them with epidermal wound healing and dermal fibrotic processes. Here, we present an overview of transmembrane collagens and put a spotlight on them as regulators of epidermal-dermal communication and as potential players in fibrinogenesis.
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Affiliation(s)
- Alexander Nyström
- Department of Dermatology, Faculty of Medicine, Medical Center - University of Freiburg, Freiburg, Germany
| | - Dimitra Kiritsi
- Department of Dermatology, Faculty of Medicine, Medical Center - University of Freiburg, Freiburg, Germany
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4
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Kroeger J, Hoppe E, Galiger C, Has C, Franzke CW. Amino acid substitution in the C-terminal domain of collagen XVII reduces laminin-332 interaction causing mild skin fragility with atrophic scarring. Matrix Biol 2019; 80:72-84. [PMID: 30316981 DOI: 10.1016/j.matbio.2018.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 01/08/2023]
Abstract
The behavior of a cell depends on how its adhesion molecules interact with the cellular microenvironment. Hemidesmosomal collagen XVII essentially contributes to cell adhesion and modulates keratinocyte directionality and proliferation during skin regeneration, however only little is known about the involved interactions. Here, we used keratinocytes from patients with junctional epidermolysis bullosa with late onset, which exclusively produce a collagen XVII mutant with the p.R1303Q mutation within its extracellular C-terminus. Although this mutant was normally expressed and targeted to the membrane and the expression of integrins α3β1, α6β4 and of laminin-332 was unchanged, the keratinocytes were less adhesive, showed migratory defects and decreased clonogenic growth. Since the p.R1303Q substitution is located within the predicted laminin-332 binding site of collagen XVII, we anticipated an altered collagen XVII-laminin-332 interaction. Indeed, the pR1303Q collagen XVII ectodomain showed decreased binding capability to laminin-332 and was less co-localized with pericellular laminin-332 molecules in cell culture. Thus, aberrant collagen XVII-laminin-332 interaction results in reduced cell adhesion, destabilized cell motility and decreased clonogenicity, which in turn lead to blister formation, delayed wound healing and skin atrophy.
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Affiliation(s)
- Jasmin Kroeger
- Department of Dermatology, Faculty of Medicine and Medical Center, University of Freiburg, Germany
| | - Esther Hoppe
- Department of Dermatology, Faculty of Medicine and Medical Center, University of Freiburg, Germany
| | - Célimène Galiger
- Department of Dermatology, Faculty of Medicine and Medical Center, University of Freiburg, Germany
| | - Cristina Has
- Department of Dermatology, Faculty of Medicine and Medical Center, University of Freiburg, Germany
| | - Claus-Werner Franzke
- Department of Dermatology, Faculty of Medicine and Medical Center, University of Freiburg, Germany; Institute for Prevention and Cancer Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Germany.
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5
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Condrat I, He Y, Cosgarea R, Has C. Junctional Epidermolysis Bullosa: Allelic Heterogeneity and Mutation Stratification for Precision Medicine. Front Med (Lausanne) 2019; 5:363. [PMID: 30761300 PMCID: PMC6362712 DOI: 10.3389/fmed.2018.00363] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/21/2018] [Indexed: 11/13/2022] Open
Abstract
Junctional epidermolysis bullosa (JEB) is a hereditary blistering disease caused by reduced dermal-epidermal adhesion due to deficiencies of one of the proteins, laminin-332, type XVII collagen, integrin α6β4 or integrin α3. Significant progress has been achieved in the development of therapies for EB, such as bone-marrow transplantation, local or systemic injections with fibroblasts or mesenchymal stromal cells, readthrough of premature termination codons, or exon skipping. These were tailored in particular for dystrophic EB, which is caused by type VII collagen deficiency and have not yet reached broad clinical practice. Recently, pioneering combined gene and stem cell therapy was successful in treating one boy with junctional EB. Beside these exclusive approaches, no specific therapy to amend the major clinical features, skin and mucosal blistering and non-healing wounds is available to date. Here we extend the mutational spectrum of junctional EB, provide a stratification of COL17A1 mutations and discuss potential molecular therapeutic approaches.
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Affiliation(s)
- Irina Condrat
- Department of Dermatology and Venerology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Department of Dermatology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj Napoca, Romania
| | - Yinghong He
- Department of Dermatology and Venerology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Rodica Cosgarea
- Department of Dermatology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj Napoca, Romania
| | - Cristina Has
- Department of Dermatology and Venerology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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6
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Has C, Nyström A, Saeidian AH, Bruckner-Tuderman L, Uitto J. Epidermolysis bullosa: Molecular pathology of connective tissue components in the cutaneous basement membrane zone. Matrix Biol 2018; 71-72:313-329. [PMID: 29627521 DOI: 10.1016/j.matbio.2018.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 01/13/2023]
Abstract
Epidermolysis bullosa (EB), a group of heritable skin fragility disorders, is characterized by blistering, erosions and chronic ulcers in the skin and mucous membranes. In some forms, the blistering phenotype is associated with extensive mutilating scarring and development of aggressive squamous cell carcinomas. The skin findings can be associated with extracutaneous manifestations in the ocular as well as gastrointestinal and vesico-urinary tracts. The phenotypic heterogeneity reflects the presence of mutations in as many as 20 different genes expressed in the cutaneous basement membrane zone, and the types and combinations of the mutations and their consequences at the mRNA and protein levels contribute to the spectrum of severity encountered in different subtypes of EB. This overview highlights the molecular genetics of EB based on mutations in the genes encoding type VII and XVII collagens as well as laminin-332. The mutations identified in these protein components of the extracellular matrix attest to their critical importance in providing stability to the cutaneous basement membrane zone, with implications for heritable and acquired diseases.
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Affiliation(s)
- Cristina Has
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Alexander Nyström
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Amir Hossein Saeidian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | - Leena Bruckner-Tuderman
- 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, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA.
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7
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Has C, He Y. Research Techniques Made Simple: Immunofluorescence Antigen Mapping in Epidermolysis Bullosa. J Invest Dermatol 2016; 136:e65-e71. [PMID: 27342035 DOI: 10.1016/j.jid.2016.05.093] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Inherited epidermolysis bullosa is a group of genetic blistering diseases with a broad spectrum of clinical severity and molecular defects. Epidermolysis bullosa results from mutations in genes encoding proteins involved in cell-cell and cell-matrix adhesion in the epidermis. Immunofluorescence antigen mapping makes use of monoclonal antibodies against proteins of the dermal-epidermal junction zone to determine the layer of skin where cleavage occurs and the relative protein abundance. It allows the diagnosis of the type and subtype of inherited epidermolysis bullosa and sheds light on molecular mechanisms underlying the disease. Immunofluorescence mapping steps include obtaining a skin biopsy sample, processing the biopsy material, antigen-antibody interaction on tissue, washing, incubation with fluorescently conjugated secondary antibodies, mounting, observation under a fluorescence microscope, and interpretation. A minimal antibody panel allows discrimination of the main epidermolysis bullosa subtypes. Extended panels can be used depending on the diagnostic or scientific question to be addressed. Immunofluorescence mapping contributed to significant progress in understanding epidermolysis bullosa, including identification of new underlying genetic mutations, mutation mechanisms, and the presence of revertant mosaicism. It is also an important tool in the assessment of the efficacy of experimental therapeutic approaches.
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Affiliation(s)
- Cristina Has
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Germany.
| | - Yinghong He
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Germany
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8
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Nishimura M, Nishie W, Shirafuji Y, Shinkuma S, Natsuga K, Nakamura H, Sawamura D, Iwatsuki K, Shimizu H. Extracellular cleavage of collagen XVII is essential for correct cutaneous basement membrane formation. Hum Mol Genet 2016; 25:328-39. [PMID: 26604146 DOI: 10.1093/hmg/ddv478] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/16/2015] [Indexed: 02/04/2023] Open
Abstract
In skin, basal keratinocytes in the epidermis are tightly attached to the underlying dermis by the basement membrane (BM). The correct expression of hemidesmosomal and extracellular matrix (ECM) proteins is essential for BM formation, and the null-expression of one molecule may induce blistering diseases associated with immature BM formation in humans. However, little is known about the significance of post-translational processing of hemidesmosomal or ECM proteins in BM formation. Here we show that the C-terminal cleavage of hemidesmosomal transmembrane collagen XVII (COL17) is essential for correct BM formation. The homozygous p.R1303Q mutation in COL17 induces BM duplication and blistering in humans. Although laminin 332, a major ECM protein, interacts with COL17 around p.R1303, the mutation leaves the binding of both molecules unchanged. Instead, the mutation hampers the physiological C-terminal cleavage of COL17 in the ECM. Consequently, non-cleaved COL17 ectodomain remnants induce the aberrant deposition of laminin 332 in the ECM, which is thought to be the major pathogenesis of the BM duplication that results from this mutation. As an example of impaired cleavage of COL17, this study shows that regulated processing of hemidesmosomal proteins is essential for correct BM organization in skin.
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Affiliation(s)
- Machiko Nishimura
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Wataru Nishie
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan,
| | - Yoshinori Shirafuji
- Department of Dermatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-Cho, Kita-Ku, Okayama 700-8558, Japan and
| | - Satoru Shinkuma
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Ken Natsuga
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Hideki Nakamura
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Daisuke Sawamura
- Department of Dermatology, Hirosaki University Graduate School of Medicine, Zaifu-Cho 5, Hirosaki 036-8562, Japan
| | - Keiji Iwatsuki
- Department of Dermatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-Cho, Kita-Ku, Okayama 700-8558, Japan and
| | - Hiroshi Shimizu
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan,
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9
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Abstract
Genodermatoses are rare genetic disorders with a broad spectrum of cutaneous and extracutaneous manifestations that have a genetic background. A thorough clinical examination, laboratory workup and morphological analyses of the skin remain crucial for the diagnosis in the era of next generation sequencing (NGS). The diagnostic algorithm depends on the clinical and molecular heterogeneity and should be adapted for each group of genodermatoses. In cases with uncharacteristic phenotypes which cannot be classified, NGS-based testing accelerates the time to diagnosis and leads to the identification of new disorders and new disease-associated genes. The new knowledge on genotype-phenotype correlations should enable revision of the classification of genodermatoses on a molecular basis.
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Affiliation(s)
- C Has
- Klinik für Dermatologie und Venerologie, Universitätsklinikum Freiburg, Hauptstraße 7, 79104, Freiburg, Deutschland.
| | - Y He
- Klinik für Dermatologie und Venerologie, Universitätsklinikum Freiburg, Hauptstraße 7, 79104, Freiburg, Deutschland
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10
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Barzegar M, Asadi-Kani Z, Mozafari N, Vahidnezhad H, Kariminejad A, Toossi P. Using immunofluorescence (antigen) mapping in the diagnosis and classification of epidermolysis bullosa: a first report from Iran. Int J Dermatol 2015. [PMID: 26220012 DOI: 10.1111/ijd.12804] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Immunofluorescence antigen mapping (IFM), is a newly introduced technique for diagnosis and classification of epidermolysis bullosa (EB) disease. The precise level of skin cleavage can be determined using monoclonal antibodies to EB-specific basement membrane zone protein. OBJECTIVE To apply IFM technique in diagnosis and classification of EB and to identify utility and limitation of this method in our clinical setting. METHODS IFM was done according to a described protocol by Pohla-Gubo et al. Monoclonal antibodies used for antigen mapping were against cytokeratin 5, cytokeratin 14, α6 integrin, β4 integrin, laminin 332, Collagen IV, and Collagen VII. RESULTS IFM was done for 95 referred patients, compromising 49 females and 46 males, aged 5 days to 45 years (mean = 9.5 years). Ninety cases were diagnosed with EB and classified as follows: EB simplex: (n = 13), junctional EB (n = 14), dystrophic EB (n = 62), and Kindler syndrome (n = 1). Diagnosis was not made in five cases as their specimens contained no blister. Confirmatory genetic analysis was done for five junctional cases from two families with clinical features of laryngo-onycho-cutaneous syndrome. Genetic molecular studies showed nonsense mutations in the last codon of exon 39 of the laminin α3a (LAMA3) gene (p.Gln57X) and a donor splice site mutation in LAMA3 (IVS57+5G>A) in the first and second family, respectively. CONCLUSION IFM technique is relatively simple to perform, and interpretation of the results is not sophisticated. The proportion of inconclusive results will be decreased if the specimens contain freshly induced blister.
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Affiliation(s)
| | - Zahra Asadi-Kani
- Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nikoo Mozafari
- Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hassan Vahidnezhad
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.,Department of Medical Genetics, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Parviz Toossi
- Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Has C, Nyström A. Epidermal Basement Membrane in Health and Disease. CURRENT TOPICS IN MEMBRANES 2015; 76:117-70. [PMID: 26610913 DOI: 10.1016/bs.ctm.2015.05.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Skin, as the organ protecting the individual from environmental aggressions, constantly meets external insults and is dependent on mechanical toughness for its preserved function. Accordingly, the epidermal basement membrane (BM) zone has adapted to enforce tissue integrity. It harbors anchoring structures created through unique organization of common BM components and expression of proteins exclusive to the epidermal BM zone. Evidence for the importance of its correct assembly and the nonredundancy of its components for skin integrity is apparent from the multiple skin blistering disorders caused by mutations in genes coding for proteins associated with the epidermal BM and from autoimmune disorders in which autoantibodies target these molecules. However, it has become clear that these proteins not only provide mechanical support but are also critically involved in tissue homeostasis, repair, and regeneration. In this chapter, we provide an overview of the unique organization and components of the epidermal BM. A special focus will be given to its function during regeneration, and in inherited and acquired diseases.
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Affiliation(s)
- Cristina Has
- Department of Dermatology, University Medical Center Freiburg, Freiburg, Germany
| | - Alexander Nyström
- Department of Dermatology, University Medical Center Freiburg, Freiburg, Germany
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12
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A Deep-Intronic FERMT1 Mutation Causes Kindler Syndrome: An Explanation for Genetically Unsolved Cases. J Invest Dermatol 2015; 135:2876-2879. [PMID: 26083552 DOI: 10.1038/jid.2015.227] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Hiremagalore R, Kubba A, Bansel S, Jerajani H. Immunofluorescence mapping in inherited epidermolysis bullosa: a study of 86 cases from India. Br J Dermatol 2015; 172:384-91. [PMID: 25070151 DOI: 10.1111/bjd.13305] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND Epidermolysis bullosa (EB) poses diagnostic challenges in infancy. In India, the diagnosis is largely clinical. There were no facilities to perform immunofluorescence mapping (IFM) until recently, and electron microscopy, which requires expertise to interpret, is limited to a few research laboratories. OBJECTIVES To describe the patterns of IFM staining in the various forms of EB in Indian patients and to correlate these findings with clinical diagnosis. METHODS We conducted a cross-sectional study of IFM findings in EB. Antibodies against type IV collagen, cytokeratin 14, laminin 332 and type VII collagen were used. Clinical correlation was performed in all cases, and concordance-discordance rates were calculated. RESULTS Eighty-six patients with a diagnosis of EB were included in the study. There were 29 with EB simplex (EBS), 18 with junctional EB (JEB) and 15 with dystrophic EB (DEB). The remaining 24 cases included rare variants, cases with overlapping clinical features and cases where the type of EB was not known. On IFM diagnosis, there were 32 cases of EBS, 15 JEB, 17 DEB and two Kindler syndrome. Two cases were not EB and 18 were inconclusive. IFM could establish the type in 12 of 15 cases (80%) that had overlapping clinical features. Most of these cases were under 1 year of age. Overall the concordance was 57% and was seen best in cases of EBS. CONCLUSIONS This is the first large study of IFM of the subtypes of EB in Indian patients. The study provides a framework for better understanding of EB in Indian patients and for better diagnosis and management, particularly in infancy.
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Affiliation(s)
- R Hiremagalore
- Department of Paediatrics and Dermatology, Centre for Human Genetics, Manipal Hospital, Indira Gandhi Institute of Child Health, Biotech Park, Electronic City Phase 1, Bangalore, 560100, India
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14
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Turcan I, Jonkman MF. Blistering disease: insight from the hemidesmosome and other components of the dermal-epidermal junction. Cell Tissue Res 2014; 360:545-69. [PMID: 25502077 DOI: 10.1007/s00441-014-2021-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 09/25/2014] [Indexed: 02/07/2023]
Abstract
The hemidesmosome is a specialized transmembrane complex that mediates the binding of epithelial cells to the underlying basement membrane. In the skin, this multiprotein structure can be regarded as the chief adhesion unit at the site of the dermal-epidermal junction. Focal adhesions are additional specialized attachment structures located between hemidesmosomes. The integrity of the skin relies on well-assembled and functional hemidesmosomes and focal adhesions (also known as integrin adhesomes). However, if these adhesion structures are impaired, e.g., as a result of circulating autoantibodies or inherited genetic mutations, the mechanical strength of the skin is compromised, leading to blistering and/or tissue inflammation. A particular clinical presentation emerges subject to the molecule that is targeted. None of these junctional complexes are simply compounds of adhesion molecules; they also play a significant role in signalling pathways involved in the differentiation and migration of epithelial cells such as during wound healing and in tumour invasion. We summarize current knowledge about hereditary and acquired blistering diseases emerging from pathologies of the hemidesmosome and its neighbouring proteins as components of the dermal-epidermal junction.
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Affiliation(s)
- Iana Turcan
- Centre for Blistering Diseases, Department of Dermatology, University Medical Centre Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands,
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15
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Has C, Chmel N, Levati L, Neri I, Sonnenwald T, Pigors M, Godbole K, Dudhbhate A, Bruckner-Tuderman L, Zambruno G, Castiglia D. FERMT1 promoter mutations in patients with Kindler syndrome. Clin Genet 2014; 88:248-54. [PMID: 25156791 DOI: 10.1111/cge.12490] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/29/2014] [Accepted: 08/19/2014] [Indexed: 10/24/2022]
Abstract
Mutations in the FERMT1 gene, encoding the focal adhesion protein kindlin-1 underlie the Kindler syndrome (KS), an autosomal recessive skin disorder with a phenotype comprising skin blistering, photosensitivity, progressive poikiloderma with extensive skin atrophy, and propensity to skin cancer. The FERMT1 mutational spectrum comprises gross genomic deletions, splice site, nonsense, and frameshift mutations, which are scattered over the coding region spanning exon 2-15. We now report three KS families with mutations affecting the promoter region of FERMT1. Two of these mutations are large deletions (∼38.0 and 1.9 kb in size) and one is a single nucleotide variant (c.-20A>G) within the 5' untranslated region (UTR). Each mutation resulted in loss of gene expression in patient skin or cultured keratinocytes. Reporter assays showed the functional relevance of the genomic regions deleted in our patients for FERMT1 gene transcription and proved the causal role of the c.-20A>G variant in reducing transcriptional activity.
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Affiliation(s)
- C Has
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
| | - N Chmel
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
| | - L Levati
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata-IRCCS, Rome, Italy
| | - I Neri
- Department of Specialised, Experimental and Diagnostic Medicine, University of Bologna, Bologna, Italy
| | - T Sonnenwald
- Department of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - M Pigors
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
| | - K Godbole
- Divisions of Genetics and Dermatology, Deenanath Mangeshkar Hospital & Center Erandawane, Pune, India
| | - A Dudhbhate
- Divisions of Genetics and Dermatology, Deenanath Mangeshkar Hospital & Center Erandawane, Pune, India
| | - L Bruckner-Tuderman
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
| | - G Zambruno
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata-IRCCS, Rome, Italy
| | - D Castiglia
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata-IRCCS, Rome, Italy
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16
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Abstract
The inherited skin fragility encompasses a heterogeneous group of disorders, collectively designated as epidermolysis bullosa, characterized by recurrent mechanically induced blisters, erosions or wounds. The spectrum of clinical manifestations is broad, as well as the molecular background. Besides the skin, mucosal membranes and other organs can be affected. In real-world practice, patients with mild genetic skin fragility usually do not require medical care and often remain underdiagnosed. In contrast, the well-defined severe EB subtypes are recognized based on typical clinical features. The molecular diagnostics is usually performed in order to allow genetic counselling and prenatal diagnosis. Besides wound care and careful management of the disease complications, new experimental targeted therapies are being developed. New very rare forms of inherited skin fragility have been identified with modern sequencing methods.
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Affiliation(s)
- C Has
- Klinik für Dermatologie und Venerologie, Universitätsklinikum Freiburg, Hauptstr. 7, 79104, Freiburg, Deutschland,
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17
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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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18
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Beyond expectations: novel insights into epidermal keratin function and regulation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:265-306. [PMID: 24952920 DOI: 10.1016/b978-0-12-800179-0.00007-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The epidermis is a stratified epithelium that relies on its cytoskeleton and cell junctions to protect the body against mechanical injury, dehydration, and infections. Keratin intermediate filament proteins are involved in many of these functions by forming cell-specific cytoskeletal scaffolds crucial for the maintenance of cell and tissue integrity. In response to various stresses, the expression and organization of keratins are altered at transcriptional and posttranslational levels to restore tissue homeostasis. Failure to restore tissue homeostasis in the presence of keratin gene mutations results in acute and chronic skin disorders for which currently no rational therapies are available. Here, we review the recent progress on the role of keratins in cytoarchitecture, adhesion, signaling, and inflammation. By focusing on epidermal keratins, we illustrate the contribution of keratin isotypes to differentiated epithelial functions.
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