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Stancic BH, Boer J, Dolenc-Voljč M, Jemec GBE. The Role of Intra-Follicular Shear Forces in Hidradenitis Suppurativa. Skin Pharmacol Physiol 2024; 36:302-303. [PMID: 38176392 DOI: 10.1159/000536067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 12/25/2023] [Indexed: 01/06/2024]
Affiliation(s)
- Bor Hrvatin Stancic
- Dermatovenerology Department, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jurr Boer
- Department of Dermatology, Deventer Hospital, Schalkhaar, The Netherlands
| | - Mateja Dolenc-Voljč
- Dermatovenerology Department, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Gregor B E Jemec
- Department of Dermatology, Zealand University Hospital and Health Sciences Faculty, Auckland, New Zealand
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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2
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Vișan MA, Căruntu C, Costache RS, Tiplica G, Costache DO. Hidradenitis suppurativa: Detangling phenotypes and identifying common denominators. J Eur Acad Dermatol Venereol 2024; 38:62-76. [PMID: 37641875 DOI: 10.1111/jdv.19481] [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: 05/15/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023]
Abstract
Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a severe impact on patients' quality of life through its recurrent and painful nature, as well as its comorbidity burden. The shift in the pathogenic paradigm from a condition of the apocrine glands to an autoinflammatory disease associated with follicular destruction has rendered its understanding difficult, as there are still large gaps in pinpointing the underlying mechanisms, which cannot currently explain the existing clinical variation and as a result, translate into suboptimal therapy. Multifactorial involvement is hypothesized, with an implication of genetic mutations, microbiome dysbiosis, cytokine upregulation and environmental factors. Clinical observation is fundamental for diagnosis, however, the marked heterogeneity in presentation leads to delays in detection and challenges in treatment selection, showcasing clear limits in defining the link between genetic aspects of HS, the role of epigenetic factors and its pathogenic pathways. There have been attempts to formulate phenotypes that could aid in prognostication and management, however, current classification schemata show significant overlap and no validation through longitudinal studies. In this context, nomenclature poses a great challenge due to the lack of global agreement in the definition of lesions, which should be addressed by future research to enable simplified recognition and allow for more precise severity scoring. This could be complemented by the addition of extra dermatologic findings or paraclinical assessment in constructing phenotypes. The development of valid, predictive and reliable classifications of HS may lead to an improvement in comprehending its pathophysiology, favouring a more personalized approach in management. This could be achieved through consensus in the characterization of clinical features and data gathering, as well as validation attempts for described phenotypes. Ultimately, the genotype-endotype-phenotype correlation in HS requires targeted, systematic inquiries and should be addressed more largely to broaden the perspective on this debilitating entity.
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Affiliation(s)
- Maria-Alexandra Vișan
- Department of Dermatology, Dr. Carol Davila University Central Military Emergency Hospital, Bucharest, Romania
| | - Constantin Căruntu
- Department of Physiology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Dermatology, 'Prof. N.C. Paulescu' National Institute of Diabetes, Nutrition and Metabolic Diseases, Bucharest, Romania
| | - Raluca Simona Costache
- Department of Internal Medicine and Gastroenterology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - George Tiplica
- Dermatology Clinic, Colentina Clinical Hospital, Bucharest, Romania
- Dermatology Discipline, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Daniel Octavian Costache
- Department of Dermatology, Dr. Carol Davila University Central Military Emergency Hospital, Bucharest, Romania
- Dermatology Discipline, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
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3
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Yamasaki R. Connexins Control Glial Inflammation in Various Neurological Diseases. Int J Mol Sci 2023; 24:16879. [PMID: 38069203 PMCID: PMC10706219 DOI: 10.3390/ijms242316879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/25/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Connexins (Cxs) form gap junctions through homotypic/heterotypic oligomerization. Cxs are initially synthesized in the endoplasmic reticulum, then assembled as hexamers in the Golgi apparatus before being integrated into the cell membrane as hemichannels. These hemichannels remain closed until they combine to create gap junctions, directly connecting neighboring cells. Changes in the intracellular or extracellular environment are believed to trigger the opening of hemichannels, creating a passage between the inside and outside of the cell. The size of the channel pore depends on the Cx isoform and cellular context-specific effects such as posttranslational modifications. Hemichannels allow various bioactive molecules, under ~1 kDa, to move in and out of the host cell in the direction of the electrochemical gradient. In this review, we explore the fundamental roles of Cxs and their clinical implications in various neurological dysfunctions, including hereditary diseases, ischemic brain disorders, degenerative conditions, demyelinating disorders, and psychiatric illnesses. The influence of Cxs on the pathomechanisms of different neurological disorders varies depending on the circumstances. Hemichannels are hypothesized to contribute to proinflammatory effects by releasing ATP, adenosine, glutamate, and other bioactive molecules, leading to neuroglial inflammation. Modulating Cxs' hemichannels has emerged as a promising therapeutic approach.
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Affiliation(s)
- Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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4
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Posukh OL, Maslova EA, Danilchenko VY, Zytsar MV, Orishchenko KE. Functional Consequences of Pathogenic Variants of the GJB2 Gene (Cx26) Localized in Different Cx26 Domains. Biomolecules 2023; 13:1521. [PMID: 37892203 PMCID: PMC10604905 DOI: 10.3390/biom13101521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/08/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
One of the most common forms of genetic deafness has been predominantly associated with pathogenic variants in the GJB2 gene, encoding transmembrane protein connexin 26 (Cx26). The Cx26 molecule consists of an N-terminal domain (NT), four transmembrane domains (TM1-TM4), two extracellular loops (EL1 and EL2), a cytoplasmic loop, and a C-terminus (CT). Pathogenic variants in the GJB2 gene, resulting in amino acid substitutions scattered across the Cx26 domains, lead to a variety of clinical outcomes, including the most common non-syndromic autosomal recessive deafness (DFNB1A), autosomal dominant deafness (DFNA3A), as well as syndromic forms combining hearing loss and skin disorders. However, for rare and poorly documented variants, information on the mode of inheritance is often lacking. Numerous in vitro studies have been conducted to elucidate the functional consequences of pathogenic GJB2 variants leading to amino acid substitutions in different domains of Cx26 protein. In this work, we summarized all available data on a mode of inheritance of pathogenic GJB2 variants leading to amino acid substitutions and reviewed published information on their functional effects, with an emphasis on their localization in certain Cx26 domains.
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Affiliation(s)
- Olga L. Posukh
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (E.A.M.); (V.Y.D.); (M.V.Z.); (K.E.O.)
- Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Ekaterina A. Maslova
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (E.A.M.); (V.Y.D.); (M.V.Z.); (K.E.O.)
- Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Valeriia Yu. Danilchenko
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (E.A.M.); (V.Y.D.); (M.V.Z.); (K.E.O.)
- Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Marina V. Zytsar
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (E.A.M.); (V.Y.D.); (M.V.Z.); (K.E.O.)
| | - Konstantin E. Orishchenko
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (E.A.M.); (V.Y.D.); (M.V.Z.); (K.E.O.)
- Novosibirsk State University, 630090 Novosibirsk, Russia
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5
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Balić A, Marinović B, Bukvić Mokos Z. The genetic aspects of hidradenitis suppurativa. Clin Dermatol 2023; 41:551-563. [PMID: 37652193 DOI: 10.1016/j.clindermatol.2023.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Genetic aspects have a substantial role in hidradenitis suppurativa (HS) pathogenesis. A positive family history of HS occurs in about one-third of HS cases and is significantly higher in patients with early onset of the disease. Recent twin studies have shown a high heritability in HS, fortifying the importance of genetic factors in disease pathogenesis. Based on existing knowledge on the genomics of HS, the disease can be categorized as familial HS, sporadic, syndromic HS, and "HS plus" associated with other syndromes. In familial HS, autosomal dominant transmission is proposed, and monogenic inheritance is rare. This monogenic trait is related to mutations of γ-secretase component genes and Notch signaling or defects in inflammasome function. With newly discovered gene mutations, such as those related to innate and adaptive immunity, skin microbiome, inflammasome, epidermal homeostasis, and keratinization pathway, we can define HS as a polygenic, multifactorial, autoinflammatory disease. To fully elucidate the genetic aspects of HS, we need extensive, long-term global collaborations.
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Affiliation(s)
- Anamaria Balić
- Department of Dermatology and Venereology, University Hospital Centre Zagreb, European Reference Network (ERN) - Skin Reference Centre, Zagreb, Croatia
| | - Branka Marinović
- Department of Dermatology and Venereology, University Hospital Centre Zagreb, European Reference Network (ERN) - Skin Reference Centre, Zagreb, Croatia; School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Zrinka Bukvić Mokos
- Department of Dermatology and Venereology, University Hospital Centre Zagreb, European Reference Network (ERN) - Skin Reference Centre, Zagreb, Croatia; School of Medicine, University of Zagreb, Zagreb, Croatia.
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6
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Travis L, Ou Yang J, Andersen RK, Skovby F, Jemec GB, Saunte DM. Keratitis-ichthyosis-deafness syndrome and hidradenitis suppurativa. JAAD Case Rep 2023; 38:158-162. [PMID: 37555193 PMCID: PMC10404597 DOI: 10.1016/j.jdcr.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023] Open
Affiliation(s)
- Lisa Travis
- Department of Dermatology, Zealand University Hospital, Roskilde, Denmark
- Ronald O. Perelman Department of Dermatology, NYU Grossman School of Medicine, New York, New York
| | - Janie Ou Yang
- Department of Dermatology, NYC Health+Hospitals/Woodhull, New York, New York
| | - Rune Kjærsgaard Andersen
- Department of Dermatology, Zealand University Hospital, Roskilde, Denmark
- Department of Immunology and Microbiology, Skin Immunology Research Center, University of Copenhagen, Copenhagen, Denmark
| | - Flemming Skovby
- Department of Clinical Genetics, Zealand University Hospital, Roskilde, University of Copenhagen, Roskilde, Denmark
| | - Gregor B.E. Jemec
- Department of Dermatology, Zealand University Hospital, Roskilde, Denmark
- Department of Clinical Medicine, Faculty of Health & Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Ditte M. Saunte
- Department of Dermatology, Zealand University Hospital, Roskilde, Denmark
- Department of Clinical Medicine, Faculty of Health & Medical Science, University of Copenhagen, Copenhagen, Denmark
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7
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Mao L, Wang Y, An L, Zeng B, Wang Y, Frishman D, Liu M, Chen Y, Tang W, Xu H. Molecular Mechanisms and Clinical Phenotypes of GJB2 Missense Variants. BIOLOGY 2023; 12:biology12040505. [PMID: 37106706 PMCID: PMC10135792 DOI: 10.3390/biology12040505] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 03/29/2023]
Abstract
The GJB2 gene is the most common gene responsible for hearing loss (HL) worldwide, and missense variants are the most abundant type. GJB2 pathogenic missense variants cause nonsyndromic HL (autosomal recessive and dominant) and syndromic HL combined with skin diseases. However, the mechanism by which these different missense variants cause the different phenotypes is unknown. Over 2/3 of the GJB2 missense variants have yet to be functionally studied and are currently classified as variants of uncertain significance (VUS). Based on these functionally determined missense variants, we reviewed the clinical phenotypes and investigated the molecular mechanisms that affected hemichannel and gap junction functions, including connexin biosynthesis, trafficking, oligomerization into connexons, permeability, and interactions between other coexpressed connexins. We predict that all possible GJB2 missense variants will be described in the future by deep mutational scanning technology and optimizing computational models. Therefore, the mechanisms by which different missense variants cause different phenotypes will be fully elucidated.
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Affiliation(s)
- Lu Mao
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou 450052, China
| | - Yueqiang Wang
- Basecare Medical Device Co., Ltd., Suzhou 215000, China
| | - Lei An
- Translational Medicine Center, Huaihe Hospital of Henan University, Kaifeng 475000, China
| | - Beiping Zeng
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou 450052, China
| | - Yanyan Wang
- The Research and Application Center of Precision Medicine, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, China
| | - Dmitrij Frishman
- Wissenschaftszentrum Weihenstephan, Technische Universitaet Muenchen, Am Staudengarten 2, 85354 Freising, Germany
| | - Mengli Liu
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou 450052, China
| | - Yanyu Chen
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou 450052, China
| | - Wenxue Tang
- The Research and Application Center of Precision Medicine, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, China
| | - Hongen Xu
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou 450052, China
- The Research and Application Center of Precision Medicine, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, China
- Correspondence:
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8
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Increased Hemichannel Activity Displayed by a Connexin43 Mutation Causing a Familial Connexinopathy Exhibiting Hypotrichosis with Follicular Keratosis and Hyperostosis. Int J Mol Sci 2023; 24:ijms24032222. [PMID: 36768546 PMCID: PMC9916973 DOI: 10.3390/ijms24032222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Mutations in the GJA1 gene that encodes connexin43 (Cx43) cause several rare genetic disorders, including diseases affecting the epidermis. Here, we examined the in vitro functional consequences of a Cx43 mutation, Cx43-G38E, linked to a novel human phenotype of hypotrichosis, follicular keratosis and hyperostosis. We found that Cx43-G38E was efficiently translated in Xenopus oocytes and localized to gap junction plaques in transfected HeLa cells. Cx43-G38E formed functional gap junction channels with the same efficiency as wild-type Cx43 in Xenopus oocytes, although voltage gating of the gap junction channels was altered. Notably, Cx43-G38E significantly increased membrane current flow through the formation of active hemichannels when compared to wild-type Cx43. These data demonstrate the association of increased hemichannel activity to a connexin mutation linked to a skeletal-cutaneous phenotype, suggesting that augmented hemichannel activity could play a role in skin and skeletal disorders caused by human Cx43 mutations.
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9
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Alsabbagh MM. Keratitis-ichthyosis-deafness syndrome: A comprehensive review of cutaneous and systemic manifestations. Pediatr Dermatol 2023; 40:19-27. [PMID: 36444857 DOI: 10.1111/pde.15201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/05/2022] [Indexed: 11/30/2022]
Abstract
Keratitis-ichthyosis-deafness syndrome is a rare genetic disease presenting with cutaneous, ocular, and otic defects. This comprehensive review provides insight into the clinical presentations, highlighting the cutaneous manifestations including histopathology and treatment options.
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Affiliation(s)
- Manahel Mahmood Alsabbagh
- Department of Molecular Medicine, Princess Al-Jawhara Center for Molecular Medicine and Inherited Disorders, Arabian Gulf University, Manama, Kingdom of Bahrain
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10
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Keyes E, Larijani M, Castelo-Soccio L, Treat JR. Severe recalcitrant hidradenitis suppurativa in a 2-year-old boy with partial trisomy 13. Pediatr Dermatol 2022; 39:491-493. [PMID: 35229889 DOI: 10.1111/pde.14949] [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: 09/28/2021] [Revised: 01/17/2022] [Accepted: 01/25/2022] [Indexed: 11/28/2022]
Abstract
We report the case of a 2-year-old boy with mosaic trisomy 13 and immunodeficiency who developed severe hidradenitis suppurativa beginning at the age of 18 months. Unresponsive to standard therapies, he exhibited a partial response to immunoglobulin replacement therapy.
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Affiliation(s)
- Emily Keyes
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mary Larijani
- Section of Dermatology, Department of General Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Leslie Castelo-Soccio
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Section of Dermatology, Department of General Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - James R Treat
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Section of Dermatology, Department of General Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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11
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Sellitto C, Li L, White TW. Connexin hemichannel inhibition ameliorates epidermal pathology in a mouse model of keratitis ichthyosis deafness syndrome. Sci Rep 2021; 11:24118. [PMID: 34916582 PMCID: PMC8677806 DOI: 10.1038/s41598-021-03627-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 12/07/2021] [Indexed: 02/05/2023] Open
Abstract
AbstractMutations in five different genes encoding connexin channels cause eleven clinically defined human skin diseases. Keratitis ichthyosis deafness (KID) syndrome is caused by point mutations in the GJB2 gene encoding Connexin 26 (Cx26) which result in aberrant activation of connexin hemichannels. KID syndrome has no cure and is associated with bilateral hearing loss, blinding keratitis, palmoplantar keratoderma, ichthyosiform erythroderma and a high incidence of childhood mortality. Here, we have tested whether a topically applied hemichhanel inhibitor (flufenamic acid, FFA) could ameliorate the skin pathology associated with KID syndrome in a transgenic mouse model expressing the lethal Cx26-G45E mutation. We found that FFA blocked the hemichannel activity of Cx26-G45E in vitro, and substantially reduced epidermal pathology in vivo, compared to untreated, or vehicle treated control animals. FFA did not reduce the expression of mutant connexin hemichannel protein, and cessation of FFA treatment allowed disease progression to continue. These results suggested that aberrant hemichannel activity is a major driver of skin disease in KID syndrome, and that the inhibition of mutant hemichannel activity could provide an attractive target to develop novel therapeutic interventions to treat this incurable disease.
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12
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The Complex and Critical Role of Glycine 12 (G12) in Beta-Connexins of Human Skin. Int J Mol Sci 2021; 22:ijms22052615. [PMID: 33807656 PMCID: PMC7961983 DOI: 10.3390/ijms22052615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/28/2022] Open
Abstract
Glycine is an amino acid with unique properties because its side chain is composed of a single hydrogen atom. It confers conformational flexibility to proteins and conserved glycines are often indicative of protein domains involving tight turns or bends. All six beta-type connexins expressed in human epidermis (Cx26, Cx30, Cx30.3, Cx31, Cx31.1 and Cx32) contain a glycine at position 12 (G12). G12 is located about halfway through the cytoplasmic amino terminus and substitutions alter connexin function in a variety of ways, in some cases altering protein interactions and leading to cell death. There is also evidence that alteration of G12 changes the structure of the amino terminus in connexin- and amino acid- specific ways. This review integrates structural, functional and physiological information about the role of G12 in connexins, focusing on beta-connexins expressed in human epidermis. The importance of G12 substitutions in these beta-connexins is revealed in two hereditary skin disorders, keratitis ichthyosis and erythrokeratodermia variabilis, both of which result from missense mutations affecting G12.
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13
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Bettoli V, Forconi R, Pezzini I, Martinello R, Scuderi V, Zedde P, Schettini N, Pacetti L, Corazza M. KID Syndrome and Hidradenitis Suppurativa: A Rare Association Responding to Surgical Treatment. Skin Appendage Disord 2020; 7:21-24. [PMID: 33614714 DOI: 10.1159/000509042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 05/29/2020] [Indexed: 11/19/2022] Open
Abstract
Background Keratitis-ichthyosis-deafness (KID) syndrome is a rare genodermatosis characterized by keratitis, neurosensorial auditory impairment and ichthyosiform skin involvement. Frequent complications of the syndrome are chronic, opportunistic cutaneous infections, and the development of skin cancers. Several cases of association between KID syndrome and other conditions, including hidradenitis suppurativa (HS), are described in the literature. This correlation could be explained by the hyperproliferative state of the epidermis, which occurs in KID syndrome and may favor follicular plugging. Objectives The aim of this study was to describe a very rare case of association between KID syndrome and HS and its complex therapeutic management. Results The failure of the drugs commonly used in HS and the excellent results of surgery, although difficult to achieve, were experienced. Conclusion Despite the technical difficulties related to surgery, namely, cutaneous superinfections, frequent dehisce of the suture, and closure by secondary intention, the authors strongly recommend the surgical approach in these patients.
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Affiliation(s)
- Vincenzo Bettoli
- Section of Dermatology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Riccardo Forconi
- Section of Dermatology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Ilaria Pezzini
- Plastic and Reconstructive Surgery, Azienda Ospedaliero-Universitaria di Ferrara, Arcispedale Sant'Anna, Ferrara, Italy
| | - Ruby Martinello
- Department of Morphology, Surgery and Experimental Medicine, Institute of Obstetrics and Gynecology, University of Ferrara, Ferrara, Italy
| | - Valeria Scuderi
- Section of Dermatology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Piera Zedde
- Section of Dermatology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Natale Schettini
- Section of Dermatology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Lucrezia Pacetti
- Section of Dermatology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Monica Corazza
- Section of Dermatology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
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Nijjar S, Maddison D, Meigh L, de Wolf E, Rodgers T, Cann MJ, Dale N. Opposing modulation of Cx26 gap junctions and hemichannels by CO 2. J Physiol 2020; 599:103-118. [PMID: 33022747 DOI: 10.1113/jp280747] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 10/02/2020] [Indexed: 01/21/2023] Open
Abstract
KEY POINTS A moderate increase in P C O 2 (55 mmHg) closes Cx26 gap junctions. This effect of CO2 is independent of changes in intra- or extracellular pH. The CO2 -dependent closing effect depends on the same residues (K125 and R104) that are required for the CO2 -dependent opening of Cx26 hemichannels. Pathological mutations of Cx26 abolish the CO2 -dependent closing of the gap junction. Elastic network modelling suggests that the effect of CO2 on Cx26 hemichannels and gap junctions is mediated through changes in the lowest entropy state of the protein. ABSTRACT Cx26 hemichannels open in response to moderate elevations of CO2 ( P C O 2 55 mmHg) via a carbamylation reaction that depends on residues K125 and R104. Here we investigate the action of CO2 on Cx26 gap junctions. Using a dye transfer assay, we found that an elevated P C O 2 of 55 mmHg greatly delayed the permeation of a fluorescent glucose analogue (NBDG) between HeLa cells coupled by Cx26 gap junctions. However, the mutations K125R or R104A abolished this effect of CO2 . Whole cell recordings demonstrated that elevated CO2 reduced the Cx26 gap junction conductance (median reduction 66.7%, 95% CI, 50.5-100.0%) but had no effect on Cx26K125R or Cx31 gap junctions. CO2 can cause intracellular acidification. Using 30 mm propionate, we found that acidification in the absence of a change in P C O 2 caused a median reduction in the gap junction conductance of 41.7% (95% CI, 26.6-53.7%). This effect of propionate was unaffected by the K125R mutation (median reduction 48.1%, 95% CI, 28.0-86.3%). pH-dependent and CO2 -dependent closure of the gap junction are thus mechanistically independent. Mutations of Cx26 associated with the keratitis ichthyosis deafness syndrome (N14K, A40V and A88V), in combination with the mutation M151L, also abolished the CO2 -dependent gap junction closure. Elastic network modelling suggests that the lowest entropy state when CO2 is bound is the closed configuration for the gap junction but the open state for the hemichannel. The opposing actions of CO2 on Cx26 gap junctions and hemichannels thus depend on the same residues and presumed carbamylation reaction.
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Affiliation(s)
- Sarbjit Nijjar
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Daniel Maddison
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Louise Meigh
- School of Life Sciences, University of Warwick, Coventry, UK
| | | | - Thomas Rodgers
- School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Martin J Cann
- Department of Biosciences, Durham University, Durham, UK
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, UK
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Progressive Deformity of the Lower Limbs in a Patient with KID (Keratitis-Ichthyosis-Deafness) Syndrome. Case Rep Orthop 2020; 2020:8747392. [PMID: 32733727 PMCID: PMC7369675 DOI: 10.1155/2020/8747392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/23/2020] [Accepted: 06/29/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose Progressive deformity of the lower limbs can be encountered in a long list of syndromic associations. The baseline tool in the management of such disorders is to approach to a definite diagnosis. Methods We describe a 4-year-old girl who presented with the clinical phenotype and genotype of congenital erythrokeratoderma, keratosis, and sensorineural hearing loss (keratitis-ichthyosis-deafness syndrome) (KID syndrome). She manifested progressive contractures of the knees associated with talipes equinovarus of the feet. The latter deformities were the main reasons behind her severe retardation in acquiring the normal locomotor functions. Results The analysis revealed mutations in intron 1 of the GJB2 gene of C.32G>A (p.Gly11Glu) and c.35delG in the compound heterozygous state. The presence in the genotype of the “dominant” mutation c.32G>A (p.Glu11Glu) was compatible with the clinical phenotype of KID syndrome. Conclusion Surgical interventions through the extension of the hamstring tendons have been performed successfully via the application of an external distraction apparatus, namely, Volkov- Oganesyan. The latter procedures resulted in total release of her awkward knee contractures. Eventually, the child was able to regain the physiological alignment of her lower limbs and resume walking. To the best of our knowledge, the overall management of this child could be the first in the literature.
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16
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Nomura T. Hidradenitis Suppurativa as a Potential Subtype of Autoinflammatory Keratinization Disease. Front Immunol 2020; 11:847. [PMID: 32508815 PMCID: PMC7251184 DOI: 10.3389/fimmu.2020.00847] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/14/2020] [Indexed: 12/11/2022] Open
Abstract
Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition, clinically characterized by boiled cysts, comedones, abscesses, hypertrophic scars, and/or sinus tracts typically in the apocrine-gland-rich areas such as the axillae, groin, and/or buttocks. Although its precise pathogenic mechanisms remain unknown, I herein emphasize the importance of the following three recent discoveries in the pathogenesis of HS: First, heterozygous loss-of-function mutations in the genes encoding γ-secretase, including NCSTN, PSENEN, and PSEN1, have been identified in some patients with HS. Such genetic alterations result in hyperkeratosis, dysregulated hair follicle differentiation, and cyst formation via aberrant Notch signaling. Furthermore, Psen1-/Psen2-, Psen1-, Ncstn+/-, and Notch1-/Notch2- mice share common phenotypes of human HS, suggesting a role of aberrant keratinization in the development of HS. Second, upregulation of interleukin 1β, interleukin-36, caspase-1, and NLRP3 and dysregulation of the Th17:Treg cell axis have been demonstrated in HS samples, suggesting that autoinflammation is a key event in the pathophysiology of the disease. Notably, HS may be complicated with other autoinflammatory diseases such as inflammatory bowel diseases and pyoderma gangrenosum, again highlighting the importance of autoinflammation in HS. Last, biologics such as adalimumab, infliximab, anakinra, ustekinumab, and secukinumab are reportedly effective for moderate-to-severe HS. These findings collectively suggest that HS is closely linked with aberrant keratinization and autoinflammation, raising the question whether it represents an autoinflammatory keratinization disease, a recently proposed disease entity. In this mini review, I introduce the concept of autoinflammatory keratinization disease and attempt to address this clinically important question.
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Affiliation(s)
- Toshifumi Nomura
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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17
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Affiliation(s)
- Nobuko Tabata
- Department of Dermatology, Red Cross Sendai Hospital, Sendai, Japan
| | - Noriko Togashi
- The Department of Neurology, Miyagi Children's Hospital, Sendai, Japan
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18
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Jfri AH, O’Brien EA, Litvinov IV, Alavi A, Netchiporouk E. Hidradenitis Suppurativa: Comprehensive Review of Predisposing Genetic Mutations and Changes. J Cutan Med Surg 2019; 23:519-527. [DOI: 10.1177/1203475419852049] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder. A genetic component in the pathogenesis is highly likely considering that ~30% to 40% of patients with HS report a family history of the disease. The genetic mutations related to HS that have been reported to date suggest HS can be inherited as a monogenic trait because of a defect in either the Notch signaling pathway or inflammasome function, or as a polygenic disorder resulting from defects in genes regulating epidermal proliferation, ceramide production, or in immune system function. This review provides a summary of genetic mutations reported in patients diagnosed with HS and discusses the mechanisms by which these genes are involved in its pathogenesis.
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Affiliation(s)
- Abdulhadi H. Jfri
- Division of Dermatology, McGill University Health Centre, Montreal, QC, Canada
| | | | - Ivan V. Litvinov
- Division of Dermatology, McGill University Health Centre, Montreal, QC, Canada
| | - Afsaneh Alavi
- Division of Dermatology, University of Toronto, Women’s College Hospital, ON, Canada
| | - Elena Netchiporouk
- Division of Dermatology, McGill University Health Centre, Montreal, QC, Canada
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19
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Tricarico PM, Boniotto M, Genovese G, Zouboulis CC, Marzano AV, Crovella S. An Integrated Approach to Unravel Hidradenitis Suppurativa Etiopathogenesis. Front Immunol 2019; 10:892. [PMID: 31105704 PMCID: PMC6494959 DOI: 10.3389/fimmu.2019.00892] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/08/2019] [Indexed: 12/21/2022] Open
Abstract
Hidradenitis suppurativa/acne inversa (HS) is a chronic inflammatory disease involving hair follicles that presents with painful nodules, abscesses, fistulae, and hypertrophic scars, typically occurring in apocrine gland bearing skin. Establishing a diagnosis of HS may take up to 7 years after disease onset. HS severely impairs the quality of life of patients and its high frequency causes significant costs for health care system. HS patients have an increased risk of developing associated diseases, such as inflammatory bowel diseases and spondyloarthropathies, thereby suggesting a common pathophysiological mechanism. Familial cases, which are around 35% of HS patients, have allowed the identification of susceptibility genes. HS is perceived as a complex disease where environmental factors trigger chronic inflammation in the skin of genetically predisposed individuals. Despite the efforts made to understand HS etiopathogenesis, the exact mechanisms at the basis of the disease need to be still unraveled. In this review, we considered all OMICs studies performed on HS and observed that OMICs contribution in the context of HS appeared as not clear enough and/or rich of useful clinical information. Indeed, most studies focused only on one aspect—genome, transcriptome, or proteome—of the disease, enrolling small numbers of patients. This is quite limiting for the genetic studies, from different geographical areas and looking at a few aspects of HS pathogenesis without any integration of the findings obtained or a comparison among different studies. A strong need for an integrated approach using OMICs tools is required to discover novel actors involved in HS etiopathogenesis. Moreover, we suggest the constitution of consortia to enroll a higher number of patients to be analyzed following common and consensus OMICs strategies. Comparison and integration with the findings present in the OMICs repositories are mandatory. In a theoretic pipeline, the Skin-OMICs profile obtained from each HS patient should be compared and integrated with repositories and literature data by using appropriate InterOMICs approach. The final goal is not only to improve the knowledge of HS etiopathogenesis but also to provide novel tools to the clinicians with the eventual aim of offering a tailored treatment for HS patients.
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Affiliation(s)
- Paola M Tricarico
- Department of Advanced Diagnostics, Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
| | - Michele Boniotto
- University of Paris Est-Créteil and INSERM U955/IMRB-Team 16, Créteil, France
| | - Giovanni Genovese
- UOC Dermatologia, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Dipartimento di Fisiopatologia Medico-Chirurgica e Dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - Christos C Zouboulis
- Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center, Brandenburg Medical School Theodor Fontane, Dessau, Germany
| | - Angelo V Marzano
- UOC Dermatologia, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Dipartimento di Fisiopatologia Medico-Chirurgica e Dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - Sergio Crovella
- Department of Advanced Diagnostics, Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
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20
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Hamadah I, Haider M, Chisti M. A novel homozygous mutation of GJB2-A new variant of keratitis-ichthyosis-deafness syndrome? JAAD Case Rep 2019; 5:283-287. [PMID: 30891482 PMCID: PMC6403109 DOI: 10.1016/j.jdcr.2019.01.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Issam Hamadah
- Dermatology Department, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mansoor Haider
- Dermatology Department, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Muzamil Chisti
- Dermatology Department, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
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21
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Has C, Küsel J, Happle R, Steinke H, Technau-Hafsi K, Fischer J. Extending the phenotypic spectrum associated with mosaicism for GJB2 mutations. Br J Dermatol 2019; 181:623-624. [PMID: 30816995 DOI: 10.1111/bjd.17838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C Has
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, Hauptstraße 7, 79104, Freiburg, Germany
| | - J Küsel
- Institute for Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, Hauptstraße 7, 79104, Freiburg, Germany
| | - R Happle
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, Hauptstraße 7, 79104, Freiburg, Germany
| | - H Steinke
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, Hauptstraße 7, 79104, Freiburg, Germany
| | - K Technau-Hafsi
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, Hauptstraße 7, 79104, Freiburg, Germany
| | - J Fischer
- Institute for Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, Hauptstraße 7, 79104, Freiburg, Germany
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22
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Connexin43 mutations linked to skin disease have augmented hemichannel activity. Sci Rep 2019; 9:19. [PMID: 30631135 PMCID: PMC6328547 DOI: 10.1038/s41598-018-37221-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 12/04/2018] [Indexed: 01/22/2023] Open
Abstract
Mutations in the gene (GJA1) encoding connexin43 (Cx43) are responsible for several rare genetic disorders, including non-syndromic skin-limited diseases. Here we used two different functional expression systems to characterize three Cx43 mutations linked to palmoplantar keratoderma and congenital alopecia-1, erythrokeratodermia variabilis et progressiva, or inflammatory linear verrucous epidermal nevus. In HeLa cells and Xenopus oocytes, we show that Cx43-G8V, Cx43-A44V and Cx43-E227D all formed functional gap junction channels with the same efficiency as wild-type Cx43, with normal voltage gating and a unitary conductance of ~110 pS. In HeLa cells, all three mutations also localized to regions of cell-cell contact and displayed a punctate staining pattern. In addition, we show that Cx43-G8V, Cx43-A44V and Cx43-E227D significantly increase membrane current flow through formation of active hemichannels, a novel activity that was not displayed by wild-type Cx43. The increased membrane current was inhibited by either 2 mM calcium, or 5 µM gadolinium, mediated by hemichannels with a unitary conductance of ~250 pS, and was not due to elevated mutant protein expression. The three Cx43 mutations all showed the same gain of function activity, suggesting that augmented hemichannel activity could play a role in skin-limited diseases caused by human Cx43 mutations.
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23
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Frew J, Vekic D, Woods J, Cains G. A systematic review and critical evaluation of reported pathogenic sequence variants in hidradenitis suppurativa. Br J Dermatol 2017; 177:987-998. [DOI: 10.1111/bjd.15441] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2017] [Indexed: 12/13/2022]
Affiliation(s)
- J.W. Frew
- Department of Dermatology; Liverpool Hospital; Sydney New South Wales Australia
- University of New South Wales; Sydney New South Wales Australia
- Ingham Institute of Applied Medical Research; Liverpool New South Wales Australia
| | - D.A. Vekic
- Department of Dermatology; Liverpool Hospital; Sydney New South Wales Australia
- University of New South Wales; Sydney New South Wales Australia
- Ingham Institute of Applied Medical Research; Liverpool New South Wales Australia
| | - J. Woods
- Department of Dermatology; Liverpool Hospital; Sydney New South Wales Australia
- University of New South Wales; Sydney New South Wales Australia
- Ingham Institute of Applied Medical Research; Liverpool New South Wales Australia
| | - G.D. Cains
- Department of Dermatology; Liverpool Hospital; Sydney New South Wales Australia
- University of New South Wales; Sydney New South Wales Australia
- Ingham Institute of Applied Medical Research; Liverpool New South Wales Australia
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24
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Gasparic J, Theut Riis P, Jemec G. Recognizing syndromic hidradenitis suppurativa: a review of the literature. J Eur Acad Dermatol Venereol 2017; 31:1809-1816. [PMID: 28696038 DOI: 10.1111/jdv.14464] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/26/2017] [Indexed: 01/06/2023]
Abstract
Hidradenitis suppurativa (HS) is an inflammatory skin disease causing painful inflammation and suppuration. It may occur in rare syndromes: follicular occlusion, Bazex-Dupré-Christol, Down's, KID, PAPASH, PASS, PASH, and SAPHO syndromes, as well as Dowling-Degos disease. An overview of syndromic HS may inform the search for aetiological factors in HS. PubMed, Ovid and Web of Science were systematically searched using '(hidradenitis OR acne invers*) AND (syndrome OR KID OR PASS OR PAPA OR PASH OR SAPHO OR bazex-dupre OR 'dowling degos' OR triad OR tetrad)' and Cochrane Library using 'hidradenitis OR acne invers*'. A total of 82 articles were included in the final review. We summarize 134 cases collected from the 82 included articles. The syndromes are discussed, focusing on etiopathogenesis, clinical presentation and treatment. This study is based on case reports; therefore, conclusions may be subject to the selection bias. These syndromes are rare; however, it is important to recognize them, as treating them may require a different approach. Three subtypes of syndromic hidradenitis are suggested: syndromes with known genetic abnormalities, syndromes characterized by follicular plugging or structural defects, and syndromes with possible autoinflammatory pathogenesis. There was no universally effective treatment for syndromic HS, and treatment was individualized.
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Affiliation(s)
- J. Gasparic
- Department of Dermatology; Zealand University Hospital; Roskilde Denmark
| | - P. Theut Riis
- Department of Dermatology; Zealand University Hospital; Roskilde Denmark
- Health Sciences Faculty; University of Copenhagen; Copenhagen Denmark
| | - G.B. Jemec
- Department of Dermatology; Zealand University Hospital; Roskilde Denmark
- Health Sciences Faculty; University of Copenhagen; Copenhagen Denmark
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25
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Srinivas M, Verselis VK, White TW. Human diseases associated with connexin mutations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:192-201. [PMID: 28457858 DOI: 10.1016/j.bbamem.2017.04.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/20/2017] [Accepted: 04/25/2017] [Indexed: 01/11/2023]
Abstract
Gap junctions and hemichannels comprised of connexins impact many cellular processes. Significant advances in our understanding of the functional role of these channels have been made by the identification of a host of genetic diseases caused by connexin mutations. Prominent features of connexin disorders are the inability of other connexins expressed in the same cell type to compensate for the mutated one, and the ability of connexin mutants to dominantly influence the activity of other wild-type connexins. Functional studies have begun to identify some of the underlying mechanisms whereby connexin channel mutation contributes to the disease state. Detailed mechanistic understanding of these functional differences will help to facilitate new pathophysiology driven therapies for the diverse array of connexin genetic disorders. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Miduturu Srinivas
- Department of Biological and Vision Sciences, SUNY College of Optometry, New York, NY 10036, USA
| | - Vytas K Verselis
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA.
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26
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Miller IM, McAndrew RJ, Hamzavi I. Prevalence, Risk Factors, and Comorbidities of Hidradenitis Suppurativa. Dermatol Clin 2016; 34:7-16. [PMID: 26617352 DOI: 10.1016/j.det.2015.08.002] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
It is challenging to estimate a true prevalence of hidradenitis suppurativa (HS) because it is underdiagnosed and misdiagnosed. Prevalences have been reported from 0.00033% to 4.1%. The incidence seems to be rising. In addition to dermatologic symptoms, HS is associated with metabolic syndrome, and increased cardiovascular risk. The majority of HS patients are smokers. Additional somatic comorbidities complicating HS include autoimmune conditions, follicular syndromes, rheumatologic conditions, and malignancies. HS patients are troubled by psychological comorbidities. When treating HS patients it is imperative not only to treat the skin symptoms, but also address the screening and treatment of possible comorbidities.
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Affiliation(s)
- Iben Marie Miller
- Department of Dermatology, Roskilde Hospital, Koegevej 7-3, Roskilde 4000, Denmark
| | - Rachel J McAndrew
- Department of Dermatology, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Iltefat Hamzavi
- Department of Dermatology, Multicultural Dermatology Center, Henry Ford Hospital, Detroit, MI 48202, USA.
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27
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Altered cellular localization and hemichannel activities of KID syndrome associated connexin26 I30N and D50Y mutations. BMC Cell Biol 2016; 17:5. [PMID: 26831144 PMCID: PMC4736630 DOI: 10.1186/s12860-016-0081-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 01/23/2016] [Indexed: 11/18/2022] Open
Abstract
Background Gap junctions facilitate exchange of small molecules between adjacent cells, serving a crucial function for the maintenance of cellular homeostasis. Mutations in connexins, the basic unit of gap junctions, are associated with several human hereditary disorders. For example, mutations in connexin26 (Cx26) cause both non-syndromic deafness and syndromic deafness associated with skin abnormalities such as keratitis-ichthyosis-deafness (KID) syndrome. These mutations can alter the formation and function of gap junction channels through different mechanisms, and in turn interfere with various cellular processes leading to distinct disorders. The KID associated Cx26 mutations were mostly shown to result in elevated hemichannel activities. However, the effects of these aberrant hemichannels on cellular processes are recently being deciphered. Here, we assessed the effect of two Cx26 mutations associated with KID syndrome, Cx26I30N and D50Y, on protein biosynthesis and channel function in N2A and HeLa cells. Results Immunostaining experiments showed that Cx26I30N and D50Y failed to form gap junction plaques at cell-cell contact sites. Further, these mutations resulted in the retention of Cx26 protein in the Golgi apparatus. Examination of hemichannel function by fluorescent dye uptake assays revealed that cells with Cx26I30N and D50Y mutations had increased dye uptake compared to Cx26WT (wild-type) containing cells, indicating abnormal hemichannel activities. Cells with mutant proteins had elevated intracellular calcium levels compared to Cx26WT transfected cells, which were abolished by a hemichannel blocker, carbenoxolone (CBX), as measured by Fluo-3 AM loading and flow cytometry. Conclusions Here, we demonstrated that Cx26I30N and D50Y mutations resulted in the formation of aberrant hemichannels that might result in elevated intracellular calcium levels, a process which may contribute to the hyperproliferative epidermal phenotypes of KID syndrome. Electronic supplementary material The online version of this article (doi:10.1186/s12860-016-0081-0) contains supplementary material, which is available to authorized users.
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28
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Connexin channels in congenital skin disorders. Semin Cell Dev Biol 2016; 50:4-12. [PMID: 26775130 DOI: 10.1016/j.semcdb.2015.11.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 11/23/2015] [Indexed: 11/22/2022]
Abstract
Gap junctions and hemichannels comprised of connexins influence epidermal proliferation and differentiation. Significant advances in our understanding of the functional role of connexins in the skin have been made by studying the diseases caused by connexin mutations. Eleven clinically defined cutaneous disorders with an overlapping spectrum of phenotypes are caused by mutations in five different connexin genes, highlighting that disease presentation must be deciphered with an understanding of how connexin functions are affected. Increasing evidence suggests that the skin diseases produced by connexin mutations result from dominant gains of function. In palmoplantar keratoderma with deafness, the connexin 26 mutations transdominantly alter the function of wild-type connexin 43 and create leaky heteromeric hemichannels. In keratitis-ichthyosis-deafness syndrome, different connexin 26 mutations can either form dominant hemichannels with altered calcium regulation or increased calcium permeability, leading to clinical subtypes of this syndrome. It is only with detailed understanding of these subtle functional differences that we can hope to create successful pathophysiology driven therapies for the connexin skin disorders.
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29
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García IE, Bosen F, Mujica P, Pupo A, Flores-Muñoz C, Jara O, González C, Willecke K, Martínez AD. From Hyperactive Connexin26 Hemichannels to Impairments in Epidermal Calcium Gradient and Permeability Barrier in the Keratitis-Ichthyosis-Deafness Syndrome. J Invest Dermatol 2016; 136:574-583. [PMID: 26777423 DOI: 10.1016/j.jid.2015.11.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 01/19/2023]
Abstract
The keratitis-ichthyosis-deafness (KID) syndrome is characterized by corneal, skin, and hearing abnormalities. KID has been linked to heterozygous dominant missense mutations in the GJB2 and GJB6 genes, encoding connexin26 and 30, respectively. In vitro evidence indicates that KID mutations lead to hyperactive (open) hemichannels, which in some cases is accompanied by abnormal function of gap junction channels. Transgenic mouse models expressing connexin26 KID mutations reproduce human phenotypes and present impaired epidermal calcium homeostasis and abnormal lipid composition of the stratum corneum affecting the water barrier. Here we have compiled relevant data regarding the KID syndrome and propose a mechanism for the epidermal aspects of the disease.
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Affiliation(s)
- Isaac E García
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Felicitas Bosen
- LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany
| | - Paula Mujica
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carolina Flores-Muñoz
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Oscar Jara
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Klaus Willecke
- LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany.
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
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30
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Abstract
Genetic skin diseases, or genodermatoses, often have extracutaneous manifestations. Ocular manifestations in particular can have significant clinical implications, like blindness. Other manifestations, such as the corneal opacities that occur in X-linked ichthyosis, are asymptomatic but characteristic of a particular genodermatosis. Ophthalmologic examination can aid in diagnosis when characteristic findings are seen. The genodermatoses with ocular manifestations will be reviewed, but neurocutaneous, syndromes, genetic pigmentary disorders, and genetic metabolic diseases are not included because they are covered elsewhere in this issue.
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Affiliation(s)
- Melinda Jen
- Section of Pediatric Dermatology, Children's Hospital of Philadelphia; Departments of Pediatrics and Dermatology, Perelman School of Medicine at the University of Pennsylvania, 3550 Market St, Second floor, Philadelphia, PA, 19104.
| | - Sudha Nallasamy
- The Vision Center, Children's Hospital Los Angeles; Department of Ophthalmology, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd, MS #88, Los Angeles, CA, 90027
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31
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Abstract
Connexin mutations underlie numerous human genetic diseases. Several connexin genes have been linked to skin diseases, and mechanistic studies have indicated that a gain of abnormal channel function may be responsible for pathology. The topical accessibility of the epidermal connexins, the existence of several mouse models of human skin disease, and the ongoing identification of pharmacological inhibitors targeting connexins provide an opportunity to test new therapeutic approaches.
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Affiliation(s)
- Noah A Levit
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, United States
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, United States.
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32
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Peart JM, Licht DJ, Prange EO, Treat JR. Intractable nodulocystic acne in a patient with trisomy 13. Pediatr Dermatol 2015; 32:381-2. [PMID: 25639329 DOI: 10.1111/pde.12511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We report the case of a boy with trisomy 13 who developed severe nodulocystic acne with sinus tract formation that has been unresponsive to multiple courses of systemic antibiotics and isotretinoin.
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Affiliation(s)
- Jenna M Peart
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel J Licht
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Erin O'Connor Prange
- Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - James R Treat
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Section of Dermatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
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Dominant De Novo Mutations in GJA1 Cause Erythrokeratodermia Variabilis et Progressiva, without Features of Oculodentodigital Dysplasia. J Invest Dermatol 2014; 135:1540-1547. [PMID: 25398053 PMCID: PMC4430428 DOI: 10.1038/jid.2014.485] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/15/2014] [Accepted: 10/27/2014] [Indexed: 12/20/2022]
Abstract
Genetic investigation of inherited skin disorders has informed understanding of skin self-renewal, differentiation, and barrier function. Erythrokeratodermia variabilis et progressiva (EKVP) is a rare, inherited skin disease characterized by transient figurate patches of erythema, localized or generalized scaling, and frequent palmoplantar keratoderma. By employing exome sequencing, we show that de novo missense mutations in GJA1 (gap junction protein alpha 1) cause EKVP. The severe, progressive skin disease in EKVP subjects with GJA1 mutations is distinct from limited cutaneous findings rarely found in the systemic disorder oculodentodigital dysplasia, also caused by dominant GJA1 mutations. GJA1 encodes connexin 43 (Cx43), the most widely expressed gap junction protein. We show that the GJA1 mutations in EKVP subjects lead to disruption of Cx43 membrane localization, and aggregation within the Golgi. These findings reveal a critical role for Cx43 in epidermal homeostasis, and provide evidence of organ-specific pathobiology resulting from different mutations within GJA1.
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34
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Levit NA, Sellitto C, Wang HZ, Li L, Srinivas M, Brink PR, White TW. Aberrant connexin26 hemichannels underlying keratitis-ichthyosis-deafness syndrome are potently inhibited by mefloquine. J Invest Dermatol 2014; 135:1033-1042. [PMID: 25229253 PMCID: PMC4363291 DOI: 10.1038/jid.2014.408] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/02/2014] [Accepted: 09/04/2014] [Indexed: 11/27/2022]
Abstract
Keratitis-ichthyosis-deafness (KID) syndrome is an ectodermal dysplasia caused by dominant mutations of connexin26 (Cx26). Loss of Cx26 function causes non-syndromic sensorineural deafness, without consequence in the epidermis. Functional analyses have revealed that a majority of KID-causing mutations confer a novel expansion of hemichannel activity, mediated by connexin channels in a non-junctional configuration. Inappropriate Cx26 hemichannel opening is hypothesized to compromise keratinocyte integrity and epidermal homeostasis. Pharmacological modulators of Cx26 are needed to assess the pathomechanistic involvement of hemichannels in the development of hyperkeratosis in KID syndrome. We have used electrophysiological assays to evaluate small molecule analogs of quinine for suppressive effects on aberrant hemichannel currents elicited by KID mutations. Here, we show that mefloquine inhibits several mutant hemichannel forms implicated in KID syndrome when expressed in Xenopus laevis oocytes (IC50≈16µM), using an extracellular divalent cation, zinc (Zn++), as a non-specific positive control for comparison (IC50≈3µM). Furthermore, we used freshly isolated transgenic keratinocytes to show that micromolar concentrations of mefloquine attenuated increased macroscopic membrane currents in primary mouse keratinocytes expressing human Cx26-G45E, a mutation causing a lethal form of KID syndrome.
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Affiliation(s)
- Noah A Levit
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Caterina Sellitto
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Hong-Zhan Wang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Leping Li
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Miduturu Srinivas
- Department of Biological and Vision Sciences, SUNY College of Optometry, New York, USA
| | - Peter R Brink
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA.
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35
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de Zwart-Storm EA, Martin PE, van Steensel MAM. Gap junction diseases of the skin: novel insights from new mutations. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.09.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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36
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Abstract
Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic follicular occlusive skin disorder characterized by recurrent abscesses, draining sinuses, and scarring, with a multifactorial pathogenesis. The answer to the question whether HS may be considered a systemic disease relies on the presence of accompanying systemic manifestations, on the proof of association with other diseases or conditions, and on the occurrence of systemic implications. We address these questions based on a systemic review of the existing literature. There are several reports in the literature of the coexistence of HS with other diseases, including pyoderma gangrenosum, PASH syndrome, Adamantiades-Behcet's disease, spondylarthropathy, Crohn's disease, SAPHO, pachyonychia congenita, Dowling-Degos disease, and the keratitis-ichthyosis-deafness (KID) syndrome. Case series exist only for Crohn's disease, while most other reports are anecdotal, thus, not providing high-quality scientific evidence. Based on well-designed studies, HS has been associated with the metabolic syndrome and with excess body weight or obesity. The link between HS and systemic associations may be attributed to common genetic or environmental factors or shared inflammatory pathways.
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Coggshall K, Farsani T, Ruben B, McCalmont TH, Berger TG, Fox LP, Shinkai K. Keratitis, ichthyosis, and deafness (KID) syndrome: A review of infectious and neoplastic complications. J Am Acad Dermatol 2013; 69:127-34. [DOI: 10.1016/j.jaad.2012.12.965] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/12/2012] [Accepted: 12/16/2012] [Indexed: 01/06/2023]
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38
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Fasciani I, Temperán A, Pérez-Atencio LF, Escudero A, Martínez-Montero P, Molano J, Gómez-Hernández JM, Paino CL, González-Nieto D, Barrio LC. Regulation of connexin hemichannel activity by membrane potential and the extracellular calcium in health and disease. Neuropharmacology 2013; 75:479-90. [PMID: 23587648 DOI: 10.1016/j.neuropharm.2013.03.040] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 10/27/2022]
Abstract
Connexins are thought to solely mediate cell-to-cell communication by forming gap junction channels composed of two membrane-spanning hemichannels positioned end-to-end. However, many if not all connexin isoforms also form functional hemichannels (i.e., the precursors of complete channels) that mediate the rapid exchange of ions, second messengers and metabolites between the cell interior and the interstitial space. Electrical and molecular signaling via connexin hemichannels is now widely recognized to be important in many physiological scenarios and pathological conditions. Indeed, mutations in connexins that alter hemichannel function have been implicated in several diseases. Here, we present a comprehensive overview of how hemichannel activity is tightly regulated by membrane potential and the external calcium concentration. In addition, we discuss the genetic mutations known to alter hemichannel function and their deleterious effects, of which a better understanding is necessary to develop novel therapeutic approaches for diseases caused by hemichannel dysfunction. This article is part of the Special Issue Section entitled 'Current Pharmacology of Gap Junction Channels and Hemichannels'.
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Affiliation(s)
- Ilaria Fasciani
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain
| | - Ana Temperán
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain
| | - Leonel F Pérez-Atencio
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain
| | - Adela Escudero
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain; Unit of Molecular Genetics-INGEM, Hospital La Paz (IDIPAZ), Madrid, Spain
| | | | - Jesús Molano
- Unit of Molecular Genetics-INGEM, Hospital La Paz (IDIPAZ), Madrid, Spain
| | - Juan M Gómez-Hernández
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain
| | - Carlos L Paino
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain
| | - Daniel González-Nieto
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain; Center for Biomedical Technology, Universidad Politécnica de Madrid, Spain
| | - Luis C Barrio
- Unit of Experimental Neurology-Neurobiology, "Ramón y Cajal" Hospital (IRYCIS), Madrid, Spain.
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39
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Keratitis, Ichthyosis and Deafness (KID) Syndrome – a Case Report. SERBIAN JOURNAL OF DERMATOLOGY AND VENEREOLOGY 2013. [DOI: 10.2478/sjdv-2013-0003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Keratitis, ichthyosis and deafness (KID) syndrome is a rare congenital ectodermal dysplasia characterized by ichthyosiform hyperkeratosis of the skin, neurosensory hearing loss and vascularizing keratitis. It is inherited as an autosomal dominant trait, now known to be due to mutations in the connexin gene.
This paper presents a case of a 20-year-old male patient with erythrokeratodermia and mild scaling since birth. He presented mild hearing impairment at the age of two and often suffered from eye inflammations. On admission, his clinical picture was typical of KID syndrome with erythrokeratodermia, neurosensory deafness, vascularizing keratitis, alopecia, palmoplantar keratosis, and nail dystrophy. The patient also had a history of recurrent infections, especially bacterial and candidal infections of the skin, auditory canals and eyes. Despite extensive skin, ocular, ear and hair manifestations, his physical and psychomotor growth and development were normal.
Adjuvant balneotherapy in Prolom Spa, along with emollient creams, significantly reduced cutaneous manifestations in our patient.
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40
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Mhaske PV, Levit NA, Li L, Wang HZ, Lee JR, Shuja Z, Brink PR, White TW. The human Cx26-D50A and Cx26-A88V mutations causing keratitis-ichthyosis-deafness syndrome display increased hemichannel activity. Am J Physiol Cell Physiol 2013; 304:C1150-8. [PMID: 23447037 DOI: 10.1152/ajpcell.00374.2012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mutations in the human gene encoding connexin 26 (Cx26 or GJB2) cause either nonsyndromic deafness or syndromic deafness associated with skin diseases. That distinct clinical disorders can be caused by different mutations within the same gene suggests that different channel activities influence the ear and skin. Here we use three different expression systems to examine the functional characteristics of two Cx26 mutations causing either mild (Cx26-D50A) or lethal (Cx26-A88V) keratitis-ichthyosis-deafness (KID) syndrome. In either cRNA-injected Xenopus oocytes, transfected HeLa cells, or transfected primary human keratinocytes, we show that both Cx26-D50A and Cx26-A88V form active hemichannels that significantly increase membrane current flow compared with wild-type Cx26. This increased membrane current accelerated cell death in low extracellular calcium solutions and was not due to increased mutant protein expression. Elevated mutant hemichannel currents could be blocked by increased extracellular calcium concentration. These results show that these two mutations exhibit a shared gain of functional activity and support the hypothesis that increased hemichannel activity is a common feature of human Cx26 mutations responsible for KID syndrome.
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Affiliation(s)
- Pallavi V Mhaske
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA
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41
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Iossa S, Marciano E, Franzé A. GJB2 Gene Mutations in Syndromic Skin Diseases with Sensorineural Hearing Loss. Curr Genomics 2012; 12:475-785. [PMID: 22547955 PMCID: PMC3219843 DOI: 10.2174/138920211797904098] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 07/27/2011] [Accepted: 08/10/2011] [Indexed: 01/10/2023] Open
Abstract
The GJB2 gene is located on chromosome 13q12 and it encodes the connexin 26, a transmembrane protein involved in cell-cell attachment of almost all tissues. GJB2 mutations cause autosomal recessive (DFNB1) and sometimes dominant (DFNA3) non-syndromic sensorineural hearing loss. Moreover, it has been demonstrated that connexins are involved in regulation of growth and differentiation of epidermis and, in fact, GJB2 mutations have also been identified in syndromic disorders with hearing loss associated with various skin disease phenotypes. GJB2 mutations associated with skin disease are, in general, transmitted with a dominant inheritance pattern. Nonsyndromic deafness is caused prevalently by a loss-of-function, while literature evidences suggest for syndromic deafness a mechanism based on gain-of-function. The spectrum of skin manifestations associated with some mutations seems to have a very high phenotypic variability. Why some mutations can lead to widely varying cutaneous manifestations is poorly understood and in particular, the reason why the skin disease-deafness phenotypes differ from each other thus remains unclear. This review provides an overview of recent findings concerning pathogenesis of syndromic deafness imputable to GJB2 mutations with an emphasis on relevant clinical genotype-phenotype correlations. After describing connexin 26 fundamental characteristics, the most relevant and recent information about its known mutations involved in the syndromic forms causing hearing loss and skin problems are summarized. The possible effects of the mutations on channel expression and function are discussed.
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42
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Scott CA, Tattersall D, O'Toole EA, Kelsell DP. Connexins in epidermal homeostasis and skin disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1952-61. [DOI: 10.1016/j.bbamem.2011.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/30/2011] [Accepted: 09/06/2011] [Indexed: 12/20/2022]
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43
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Lazic T, Li Q, Frank M, Uitto J, Zhou LH. Extending the phenotypic spectrum of keratitis-ichthyosis-deafness syndrome: report of a patient with GJB2 (G12R) Connexin 26 mutation and unusual clinical findings. Pediatr Dermatol 2012; 29:349-57. [PMID: 22011219 DOI: 10.1111/j.1525-1470.2011.01425.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Keratitis-ichthyosis-deafness (KID) syndrome is a rare ectodermal dysplasia, characterized mainly by the presence of hyperkeratotic skin lesions, neurosensory hearing loss, and vascularizing keratitis. Most mutations that have been discovered as a cause of KID syndrome are autosomal dominant, found in exon 2 of the Connexin (Cx) 26 gene. A G12R (p.Gly12Arg) is a GJB2 mutation reported in only two patients with KID syndrome to date. This article describes a patient with the G12R mutation and KID syndrome with interesting additional features, which include a porokeratotic eccrine ostial and dermal duct nevus, follicular occlusion triad, and unusual persistent oral mucosal papules. We compare this patient's phenotype with the only two other patients described with the same (G12R) mutation. The phenotypic heterogeneity of KID syndrome, inexplicable according to our current understanding of these proteins, speaks to the complexity of the connexin system and its overlapping expression patterns in different tissues.
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Affiliation(s)
- Tamara Lazic
- Department of Dermatology and Skin Surgery, Roger Williams Medical Center/Boston University School of Medicine, Providence, RI 02908, USA
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Chi J, Li L, Liu M, Tan J, Tang C, Pan Q, Wang D, Zhang Z. Pathogenic connexin-31 forms constitutively active hemichannels to promote necrotic cell death. PLoS One 2012; 7:e32531. [PMID: 22393412 PMCID: PMC3290583 DOI: 10.1371/journal.pone.0032531] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Accepted: 01/27/2012] [Indexed: 11/18/2022] Open
Abstract
Mutations in Connexin-31 (Cx31) are associated with multiple human diseases including erythrokeratodermia variabilis (EKV). The molecular action of Cx31 pathogenic mutants remains largely elusive. We report here that expression of EKV pathogenic mutant Cx31R42P induces cell death with necrotic characteristics. Inhibition of hemichannel activity by a connexin hemichannel inhibitor or high extracellular calcium suppresses Cx31R42P-induced cell death. Expression of Cx31R42P induces ER stress resulting in reactive oxygen species (ROS) production, in turn, to regulate gating of Cx31R42P hemichannels and Cx31R42P induced cell death. Moreover, Cx31R42P hemichannels play an important role in mediating ATP release from the cell. In contrast, no hemichannel activity was detected with cells expressing wildtype Cx31. Together, the results suggest that Cx31R42P forms constitutively active hemichannels to promote necrotic cell death. The Cx31R42P active hemichannels are likely resulted by an ER stress mediated ROS overproduction. The study identifies a mechanism of EKV pathogenesis induced by a Cx31 mutant and provides a new avenue for potential treatment strategy of the disease.
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Affiliation(s)
- Jingwei Chi
- The State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan, China
| | - Li Li
- The State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan, China
| | - Mujun Liu
- School of Biological Science and Technology, Central South University, Changsha, Hunan, China
| | - Jieqiong Tan
- The State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan, China
| | - Chengyuan Tang
- The State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan, China
| | - Qian Pan
- The State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan, China
| | - Danling Wang
- The State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan, China
| | - Zhuohua Zhang
- The State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan, China
- * E-mail:
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Mese G, Sellitto C, Li L, Wang HZ, Valiunas V, Richard G, Brink PR, White TW. The Cx26-G45E mutation displays increased hemichannel activity in a mouse model of the lethal form of keratitis-ichthyosis-deafness syndrome. Mol Biol Cell 2011; 22:4776-86. [PMID: 22031297 PMCID: PMC3237621 DOI: 10.1091/mbc.e11-09-0778] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Mutations in the GJB2 gene (Cx26) cause deafness in humans. Most are loss-of-function mutations and cause nonsyndromic deafness. Some mutations produce a gain of function and cause syndromic deafness associated with skin disorders, such as keratitis-ichthyosis-deafness syndrome (KIDS). Cx26-G45E is a lethal mutation linked to KIDS that forms constitutively active connexin hemichannels. The pathomechanism(s) by which mutant Cx26 hemichannels perturb normal epidermal cornification are poorly understood. We created an animal model for KIDS by generating an inducible transgenic mouse expressing Cx26-G45E in keratinocytes. Cx26-G45E mice displayed reduced viability, hyperkeratosis, scaling, skin folds, and hair loss. Histopathology included hyperplasia, acanthosis, papillomatosis, increased cell size, and osteal plugging. These abnormalities correlated with human KIDS pathology and were associated with increased hemichannel currents in transgenic keratinocytes. These results confirm the pathogenic nature of the G45E mutation and provide a new model for studying the role of aberrant connexin hemichannels in epidermal differentiation and inherited connexin disorders.
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Affiliation(s)
- Gulistan Mese
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA
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46
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Pathological hemichannels associated with human Cx26 mutations causing Keratitis-Ichthyosis-Deafness syndrome. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:2014-9. [PMID: 21933663 DOI: 10.1016/j.bbamem.2011.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/30/2011] [Accepted: 09/06/2011] [Indexed: 12/25/2022]
Abstract
Connexin (Cx) proteins form intercellular gap junction channels by first assembling into single membrane hemichannels that then dock to connect the cytoplasm of two adjacent cells. Gap junctions are highly specialized structures that allow the direct passage of small molecules between cells to maintain tissue homeostasis. Functional activity of nonjunctional hemichannels has now been shown in several experimental systems. Hemichannels may constitute an important diffusional exchange pathway with the extracellular space, but the extent of their normal physiological role is currently unknown. Aberrant hemichannel activity has been linked to mutations of connexin proteins involved in genetic diseases. Here, we review a proposed role for hemichannels in the pathogenesis of Keratitis-Ichthyosis-Deafness (KID) syndrome associated with connexin26 (Cx26) mutations. Continued functional evaluation of mutated hemichannels linked to human hereditary disorders may provide additional insights into the mechanisms governing their regulation in normal physiology and dysregulation in disease. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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47
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Abstract
Cx (connexin) proteins are components of gap junctions which are aqueous pores that allow intercellular exchange of ions and small molecules. Mutations in Cx genes are linked to a range of human disorders. In the present review we discuss mutations in β-Cx genes encoding Cx26, Cx30, Cx30.3 and Cx31 which lead to skin disease and deafness. Functional studies with Cx proteins have given insights into disease-associated mechanisms and non-gap junctional roles for Cx proteins.
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48
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Fimmel S, Zouboulis CC. Comorbidities of hidradenitis suppurativa (acne inversa). DERMATO-ENDOCRINOLOGY 2011; 2:9-16. [PMID: 21547142 DOI: 10.4161/derm.2.1.12490] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 05/25/2010] [Indexed: 12/31/2022]
Abstract
Comorbidities of hidradenitis suppurativa (acne inversa) were reviewed by extracting original and review publications included in MEDLINE, EMBASE and COCHRANE libraries using the terms "hidradenitis," "Verneuil" and "acne inversa." Follicular occlusion disorders, inflammatory bowel diseases, especially Crohn disease, spondylarthropathy, other hyperergic diseases, genetic keratin disorders associated with follicular occlusion and squamous cell carcinoma were the most common hidradenitis suppurativa comorbid diseases. A first classification of these major comorbidities and their possible genetic background reveals a list of chromosome loci and genes, which could be hidradenitis suppurativa candidates. Most of these diseases belong to the group of autoinflammatory disorders, where th17 cell cytokines seem to play a central role.
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Affiliation(s)
- Sabine Fimmel
- Laboratory for Biogerontology; Dermato-Pharmacology and Dermato-Endocrinology; Institute of Clinical Pharmacology and Toxicology; Campus Benjamin Franklin; Charité Universitaetsmedizin Berlin, Germany
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49
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A novel missense mutation in the connexin30 causes nonsyndromic hearing loss. PLoS One 2011; 6:e21473. [PMID: 21731760 PMCID: PMC3123352 DOI: 10.1371/journal.pone.0021473] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 06/01/2011] [Indexed: 11/26/2022] Open
Abstract
Dysfunctional gap junctions caused by GJB2 (CX26) and GJB6 (CX30) mutations are implicated in nearly half of nonsyndromic hearing loss cases. A recent study identified a heterozygous mutation, c.119C>T (p.A40V), in the GJB6 gene of patients with nonsyndromic hearing loss. However, the functional role of the mutation in hearing loss remains unclear. In this study, analyses of cell biology indicated that a p.A40V missense mutation of CX30 causes CX30 protein accumulation in the Golgi body rather than in the cytoplasmic membrane. The tet-on protein expression system was used for further study of mutant proteins in CX30 and CX30A40V co-expressions and in CX26 and CX30A40V co-expressions. The p.A40V missense mutation exerted a dominant negative effect on both normal CX30 and CX26, which impaired gap junction formation. Moreover, computer-assisted modeling suggested that this p.A40V mutation affects the intra molecular interaction in the hydrophobic core of Trp44, which significantly alters the efficiency of gap junction formation. These findings suggest that the p.A40V mutation in CX30 causes autosomal-dominant nonsyndromic hearing loss. These data provide a novel molecular explanation for the role of GJB6 in hearing loss.
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50
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Bazazzadegan N, Sheffield AM, Sobhani M, Kahrizi K, Meyer NC, Van Camp G, Hilgert N, Abedini SS, Habibi F, Daneshi A, Nishimura C, Avenarius MR, Farhadi M, Smith RJH, Najmabadi H. Two Iranian families with a novel mutation in GJB2 causing autosomal dominant nonsyndromic hearing loss. Am J Med Genet A 2011; 155A:1202-11. [PMID: 21484990 DOI: 10.1002/ajmg.a.33209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 10/17/2009] [Indexed: 11/09/2022]
Abstract
Mutations in GJB2, encoding connexin 26 (Cx26), cause both autosomal dominant and autosomal recessive nonsyndromic hearing loss (ARNSHL) at the DFNA3 and DFNB1 loci, respectively. Most of the over 100 described GJB2 mutations cause ARNSHL. Only a minority has been associated with autosomal dominant hearing loss. In this study, we present two families with autosomal dominant nonsyndromic hearing loss caused by a novel mutation in GJB2 (p.Asp46Asn). Both families were ascertained from the same village in northern Iran consistent with a founder effect. This finding implicates the D46N missense mutation in Cx26 as a common cause of deafness in this part of Iran mandating mutation screening of GJB2 for D46N in all persons with hearing loss who originate from this geographic region.
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Affiliation(s)
- Niloofar Bazazzadegan
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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