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Marsella R, Ahrens K, Wilkes R. Studies Using Antibodies against Filaggrin and Filaggrin 2 in Canine Normal and Atopic Skin Biopsies. Animals (Basel) 2024; 14:478. [PMID: 38338121 PMCID: PMC10854974 DOI: 10.3390/ani14030478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/10/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024] Open
Abstract
Filaggrin is important for the skin barrier and atopic dermatitis. Another filaggrin-like protein, filaggrin 2, has been described. We evaluated antibodies against both filaggrins in normal and atopic skin biopsies from dogs before and after allergen challenges (D0, D1, D3 and D10). Filaggrins expression was evaluated by immunohistochemistry and Western blot. We used PCR to investigate changes in filaggrin gene expression. Effects of group (p = 0.0134) and time (p = 0.0422) were shown for the intensity of filaggrin staining. Only an effect of group was found for filaggrin 2 (p = 0.0129). Atopic samples had higher intensity of staining than normal dogs [filaggrin on D3 (p = 0.0155) and filaggrin 2 on D3 (p = 0.0038) and D10 (p < 0.0001)]. Atopic samples showed increased epidermal thickness after allergen exposure (D3 vs. D0, p = 0.005), while normal dogs did not. In atopic samples, significant increased gene expression was found for filaggrin overtime but not for filaggrin 2. Western blot showed an increase in filaggrin 2 on D3. A small size band (15 kD) containing a filaggrin sequence was found in Western blots of atopic samples only. We conclude that atopic skin reacts to allergen exposure by proliferating and increasing filaggrin production but that it also has more extensive filaggrin degradation compared to normal skin.
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Affiliation(s)
- Rosanna Marsella
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA; (K.A.); (R.W.)
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Paul AA, Szulc NA, Kobiela A, Brown SJ, Pokrzywa W, Gutowska-Owsiak D. In silico analysis of the profilaggrin sequence indicates alterations in the stability, degradation route, and intracellular protein fate in filaggrin null mutation carriers. Front Mol Biosci 2023; 10:1105678. [PMID: 37200867 PMCID: PMC10185843 DOI: 10.3389/fmolb.2023.1105678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 04/19/2023] [Indexed: 05/20/2023] Open
Abstract
Background: Loss of function mutation in FLG is the major genetic risk factor for atopic dermatitis (AD) and other allergic manifestations. Presently, little is known about the cellular turnover and stability of profilaggrin, the protein encoded by FLG. Since ubiquitination directly regulates the cellular fate of numerous proteins, their degradation and trafficking, this process could influence the concentration of filaggrin in the skin. Objective: To determine the elements mediating the interaction of profilaggrin with the ubiquitin-proteasome system (i.e., degron motifs and ubiquitination sites), the features responsible for its stability, and the effect of nonsense and frameshift mutations on profilaggrin turnover. Methods: The effect of inhibition of proteasome and deubiquitinases on the level and modifications of profilaggrin and processed products was assessed by immunoblotting. Wild-type profilaggrin sequence and its mutated variants were analysed in silico using the DEGRONOPEDIA and Clustal Omega tool. Results: Inhibition of proteasome and deubiquitinases stabilizes profilaggrin and its high molecular weight of presumably ubiquitinated derivatives. In silico analysis of the sequence determined that profilaggrin contains 18 known degron motifs as well as multiple canonical and non-canonical ubiquitination-prone residues. FLG mutations generate products with increased stability scores, altered usage of the ubiquitination marks, and the frequent appearance of novel degrons, including those promoting C-terminus-mediated degradation routes. Conclusion: The proteasome is involved in the turnover of profilaggrin, which contains multiple degrons and ubiquitination-prone residues. FLG mutations alter those key elements, affecting the degradation routes and the mutated products' stability.
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Affiliation(s)
- Argho Aninda Paul
- Experimental and Translational Immunology Group, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Natalia A. Szulc
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Adrian Kobiela
- Experimental and Translational Immunology Group, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Sara J. Brown
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
| | - Wojciech Pokrzywa
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Danuta Gutowska-Owsiak
- Experimental and Translational Immunology Group, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
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Hoober JK, Eggink LL. The Discovery and Function of Filaggrin. Int J Mol Sci 2022; 23:ijms23031455. [PMID: 35163390 PMCID: PMC8835998 DOI: 10.3390/ijms23031455] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/17/2022] [Accepted: 01/26/2022] [Indexed: 12/11/2022] Open
Abstract
Keratohyalin granules were discovered in the mid-19th century in cells that terminally differentiate to form the outer, cornified layer of the epidermis. The first indications of the composition of these structures emerged in the 1960s from a histochemical stain for histidine, followed by radioautographic evidence of a high incidence of histidine incorporation into newly synthesized proteins in cells containing the granules. Research during the next three decades revealed the structure and function of a major protein in these granules, which was initially called the ‘histidine-rich protein’. Steinert and Dale named the protein ‘filaggrin’ in 1981 because of its ability to aggregate keratin intermediate filaments. The human gene for the precursor, ‘profilaggrin,’ was reported in 1991 to encode 10, 11 or 12 nearly identical repeats. Remarkably, the mouse and rat genes encode up to 20 repeats. The lifetime of filaggrin is the time required for keratinocytes in the granular layer to move into the inner cornified layer. During this transition, filaggrin facilitates the collapse of corneocytes into ‘building blocks’ that become an impermeable surface barrier. The subsequent degradation of filaggrin is as remarkable as its synthesis, and the end-products aid in maintaining moisture in the cornified layer. It was apparent that ichthyosis vulgaris and atopic dermatitis were associated with the absence of this protein. McLean’s team in 2006 identified the cause of these diseases by discovering loss-of-function mutations in the profilaggrin gene, which led to dysfunction of the surface barrier. This story illustrates the complexity in maintaining a healthy, functional epidermis.
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Genetics and Individual Predispositions in Contact Dermatitis. Contact Dermatitis 2021. [DOI: 10.1007/978-3-030-36335-2_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Atopic dermatitis (AD) is a common frequent chronic inflammatory skin disease which begins frequently in infancy. The clinical expression of AD is a recurrent eczema on a dry skin. AD is a multifactorial disease characterized by two linked abnormalities: a skin barrier defect and a cellular inflammation, with type-2 main components. However, the pathophysiology of AD is not as simple as this description looks like. In this review, we will present a synthesis of current knowledge on natural history of AD and the involved factors, in order to clarify AD care. The evolution of AD is associated with many atopic comorbidities, following the "atopic march" scheme: IgE-mediated food allergy, allergic asthma and rhinitis occurring classically after AD. In fact, this is rarely the case, but the atopic march seems to be associated with AD severity. AD has also many neuropsychological complications which are essential to be detected. Other factors could influence the natural history of AD: genetic mutations on different genes (proteins of skin barrier, innate and adaptive immunity pathways), skin dysbiosis with colonization by Staphylococcus aureus, sensitization against environmental proteins. AD treatment is based on the restauration of the skin barrier using emollients and on anti-inflammatory drugs (notably topical corticosteroids) during the inflammatory flares. It is not recommended to treat the skin colonization by S. aureus, excepted in case of skin infection. The probiotics have no efficiency as curative treatment of AD, but could have an interest for the primary prevention, especially in at-risk populations. © 2019 Elsevier Masson SAS. All rights reserved.
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Affiliation(s)
- C Braun
- Centre international de recherche en infectiologie (CIRI) (International Center for Infectiology Research), INSERM U1111, CNRS UMR 5308, 21 avenue Tony-Garnier, 69007 Lyon, France; Hospices civils de Lyon, service de pneumologie et allergologie pédiatriques, hôpital Femme-Mère-Enfant, Bron, France.
| | - A Nosbaum
- Centre international de recherche en infectiologie (CIRI) (International Center for Infectiology Research), INSERM U1111, CNRS UMR 5308, 21 avenue Tony-Garnier, 69007 Lyon, France; Hospices civils de Lyon, service d'allergologie et immunologie clinique, centre hospitalier Lyon-Sud, Pierre-Bénite, France
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Ravnborg N, Ambikaibalan D, Agnihotri G, Price S, Rastogi S, Patel KR, Singam V, Andersen Y, Halling AS, Silverberg JI, Egeberg A, Thyssen JP. Prevalence of asthma in patients with atopic dermatitis: A systematic review and meta-analysis. J Am Acad Dermatol 2020; 84:471-478. [PMID: 32112994 DOI: 10.1016/j.jaad.2020.02.055] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/07/2020] [Accepted: 02/14/2020] [Indexed: 12/25/2022]
Abstract
BACKGROUND It is well established that asthma is common in patients with atopic dermatitis (AD). OBJECTIVES We performed a systematic review and meta-analysis to determine the prevalence of asthma and respiratory symptoms in individuals with AD as well as the association between AD and asthma. METHODS At least 2 authors independently searched the medical databases PubMed, EMBASE, LILACS, and SCOPUS for all English-language studies with data on asthma prevalence among patients with AD or the association between AD and asthma. Pooled odds ratios with 95% confidence intervals (CIs) and pooled proportions were estimated with random-effects models. The Newcastle-Ottawa scale was used to assess study quality. RESULTS The search yielded 39,503 articles. Of these, 213 studies were included in a quantitative analysis. The overall pooled prevalence of asthma was 25.7% (95% CI, 23.7-27.7) in patients with AD and 8.1% (95% CI, 7.0-9.4) among reference individuals. There was a significant association between AD and asthma when compared with reference individuals (odds ratio, 3.03; 95% CI, 2.64-3.47). LIMITATIONS The definitions of AD and asthma differed across the included studies and varied from self-report to physician diagnosed. CONCLUSIONS Asthma is a common comorbidity of AD. Physicians should be cognizant of this relationship and address asthma symptoms in their patients.
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Affiliation(s)
- Nanna Ravnborg
- Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Copenhagen Research Group for Inflammatory Skin (CORGIS), Hellerup, Denmark
| | - Danni Ambikaibalan
- Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Copenhagen Research Group for Inflammatory Skin (CORGIS), Hellerup, Denmark
| | | | - Shmuel Price
- Midwestern University Chicago College of Osteopathic Medicine, Illinois
| | - Supriya Rastogi
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Kevin R Patel
- Rosalind Franklin University of Medicine and Science, North Chicago, Illinois
| | - Vivek Singam
- University of Missouri-Kansas City School of Medicine, Kansas City, Missouri
| | - Yuki Andersen
- Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Copenhagen Research Group for Inflammatory Skin (CORGIS), Hellerup, Denmark
| | - Anne-Sofie Halling
- Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Copenhagen Research Group for Inflammatory Skin (CORGIS), Hellerup, Denmark
| | - Jonathan I Silverberg
- Northwestern University Feinberg School of Medicine, Chicago, Illinois; Northwestern Medicine Multidisciplinary Eczema Center, Chicago, Illinois
| | - Alexander Egeberg
- Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Copenhagen Research Group for Inflammatory Skin (CORGIS), Hellerup, Denmark
| | - Jacob P Thyssen
- Department of Dermatology and Venereology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
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Genetics and Individual Predispositions in Contact Dermatitis. Contact Dermatitis 2020. [DOI: 10.1007/978-3-319-72451-5_2-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Uche LE, Gooris GS, Bouwstra JA, Beddoes CM. Barrier Capability of Skin Lipid Models: Effect of Ceramides and Free Fatty Acid Composition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15376-15388. [PMID: 31698908 DOI: 10.1021/acs.langmuir.9b03029] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The skin is an effective barrier that prevents the influx of harmful substances from the environment and the efflux of body fluid. This barrier function is ascribed to the intercellular lipids present in the outermost layer of the skin referred to as the stratum corneum (SC). These lipids are composed mainly of ceramides (CERs), cholesterol, and free fatty acids (FFAs). Alterations in the SC lipid composition and barrier function impairment occur in several skin diseases including atopic dermatitis (AD). As the etiology of AD is multifactorial, establishing the relationship between the changes in SC lipid composition and barrier function impairment in the patients remains a challenge. Here, we employed model membrane systems to investigate the contribution of various anomalies in the SC CER and FFA composition observed in AD patients' skin to the barrier dysfunction. Using ethyl-p-aminobenzoate permeation and transepidermal water loss values as markers for barrier function, we determined that the alterations in SC lipid composition contribute to the impaired barrier function in AD patients. By the use of biophysical techniques, we established that the largest reduction in barrier capability was observed in the model with an increased fraction of short-chain FFAs, evident by the decrease in chain packing density. Modulations in the CER subclass composition impacted the lamellar organization while having a smaller effect on the barrier function. These findings provide evidence that AD therapies normalizing the FFA composition are at least as important as normalizing CER composition.
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Affiliation(s)
- Lorretta E Uche
- Division BioTherapeutics, Leiden Academic Centre for Drug Research , Leiden University , 2333 CC Leiden , Netherlands
| | - Gerrit S Gooris
- Division BioTherapeutics, Leiden Academic Centre for Drug Research , Leiden University , 2333 CC Leiden , Netherlands
| | - Joke A Bouwstra
- Division BioTherapeutics, Leiden Academic Centre for Drug Research , Leiden University , 2333 CC Leiden , Netherlands
| | - Charlotte M Beddoes
- Division BioTherapeutics, Leiden Academic Centre for Drug Research , Leiden University , 2333 CC Leiden , Netherlands
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9
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Danso MO, van Drongelen V, Mulder A, van Esch J, Scott H, van Smeden J, El Ghalbzouri A, Bouwstra JA. TNF-α and Th2 cytokines induce atopic dermatitis-like features on epidermal differentiation proteins and stratum corneum lipids in human skin equivalents. J Invest Dermatol 2014; 134:1941-1950. [PMID: 24518171 DOI: 10.1038/jid.2014.83] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 01/23/2014] [Accepted: 01/24/2014] [Indexed: 02/07/2023]
Abstract
Atopic dermatitis (AD) is a chronic inflammatory skin disease in which the skin barrier function is disrupted. In this inflammatory AD environment, cytokines are upregulated, but the cytokine effect on the AD skin barrier is not fully understood. We aimed to investigate the influence of Th2 (IL-4, IL-13, IL-31) and pro-inflammatory (tumor necrosis factor alpha (TNF-α)) cytokines on epidermal morphogenesis, proliferation, differentiation, and stratum corneum lipid properties. For this purpose, we used the Leiden epidermal model (LEM) in which the medium was supplemented with these cytokines. Our results show that IL-4, IL-13, IL-31, and TNF-α induce spongiosis, augment TSLP secretion by keratinocytes, and alter early and terminal differentiation-protein expression in LEMs. TNF-α alone or in combination with Th2 cytokines decreases the level of long chain free fatty acids (FFAs) and ester linked ω-hydroxy (EO) ceramides, consequently affecting the lipid organization. IL-31 increases long chain FFAs in LEMs but decreases relative abundance of EO ceramides. These findings clearly show that supplementation with TNF-α and Th2 cytokines influence epidermal morphogenesis and barrier function. As a result, these LEMs show similar characteristics as found in AD skin and can be used as an excellent tool for screening formulations and drugs for the treatment of AD.
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Affiliation(s)
- Mogbekeloluwa O Danso
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Vincent van Drongelen
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands; Department of Dermatology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Aat Mulder
- Department of Dermatology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jeltje van Esch
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Hannah Scott
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Jeroen van Smeden
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | | | - Joke A Bouwstra
- Department of Drug Delivery Technology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands.
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10
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Flohr C, Mann J. New insights into the epidemiology of childhood atopic dermatitis. Allergy 2014; 69:3-16. [PMID: 24417229 DOI: 10.1111/all.12270] [Citation(s) in RCA: 303] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2013] [Indexed: 12/31/2022]
Abstract
There is a growing desire to explain the worldwide rise in the prevalence of atopic dermatitis (AD). Trend data on the burden of AD suggest that the picture in the developing world may soon resemble that of wealthier nations, where AD affects over 20% of children. This, combined with significant variations in prevalence within countries, emphasizes the importance of environmental factors. Many hypotheses have been explored, from the modulation of immune priming by hygiene, gut microbiota diversity, and exposure to endotoxins through farm animals to the effects of pollution, climate, and diet. The discovery of the filaggrin skin barrier gene and its importance in AD development and severity has brought the focus on gene-environment interactions and the identification of environmental factors that impact on skin barrier function. This article reviews our current understanding of the epidemiology of AD, with an emphasis on the findings reported in the international literature over the last 5 years.
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Affiliation(s)
- C. Flohr
- Departments of Paediatric Dermatology & Children's Allergies; St John's Institute of Dermatology; Guy's and St Thomas’ Hospitals NHS Foundation Trust and King's College; London UK
| | - J. Mann
- Department of Dermatology; Medway NHS Foundation Trust; Medway Maritime Hospital; Gillingham Kent UK
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11
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Kruse LV, Nyegaard M, Christensen U, Møller-Larsen S, Haagerup A, Deleuran M, Hansen LG, Venø SK, Goossens D, Del-Favero J, Børglum AD. A genome-wide search for linkage to allergic rhinitis in Danish sib-pair families. Eur J Hum Genet 2012; 20:965-72. [PMID: 22419170 PMCID: PMC3421129 DOI: 10.1038/ejhg.2012.46] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Allergic rhinitis (AR) is a complex disorder with a polygenic, multifactorial aetiology. Twin studies have found the genetic contribution to be substantial. We collected and clinically characterised a sample consisting of 127 Danish nuclear families with at least two siblings suffering from AR or allergic conjunctivitis including 540 individuals (286 children and 254 parents). A whole-genome linkage scan, using 424 microsatellite markers, was performed on both this sample and an earlier collected sample consisting of 130 families with atopic dermatitis and other atopic disorders. A third sib-pair family sample, which was previously collected and genotyped, was added to the analysis increasing the total sample size to 357 families consisting of 1508 individuals. In total, 190 families with AR was included. The linkage analysis software Genehunter NPL, Genehunter MOD, and Genehunter Imprinting were used to obtain nonparametric and parametric linkage results. Family-based association analysis of positional candidate SNPs was carried out using the FBAT program. We obtained genome-wide significant linkage to a novel AR locus at 1p13 and suggestive linkage to two novel regions at 1q31-q32 and 20p12, respectively. Family-based association analysis of SNPs in the candidate locus DNND1B/CRB1 at 1q31 showed no significant association and could not explain the linkage signal observed. Suggestive evidence of linkage was also obtained at three AR loci previously reported (2q14-q23, 2q23, and 12p13) and indication of linkage was observed at a number of additional loci. Likely maternal imprinting was observed at 2q23, and possible maternal imprinting at 3q28.
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12
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Affiliation(s)
- Alan D Irvine
- National Children's Research Centre and Department of Paediatric Dermatology, Our Lady's Children's Hospital, and Trinity College, Dublin, United Kingdom
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13
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Gruber R, Elias PM, Crumrine D, Lin TK, Brandner JM, Hachem JP, Presland RB, Fleckman P, Janecke AR, Sandilands A, McLean WHI, Fritsch PO, Mildner M, Tschachler E, Schmuth M. Filaggrin genotype in ichthyosis vulgaris predicts abnormalities in epidermal structure and function. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2252-63. [PMID: 21514438 DOI: 10.1016/j.ajpath.2011.01.053] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 01/13/2011] [Accepted: 01/25/2011] [Indexed: 12/16/2022]
Abstract
Although it is widely accepted that filaggrin (FLG) deficiency contributes to an abnormal barrier function in ichthyosis vulgaris and atopic dermatitis, the pathomechanism of how FLG deficiency provokes a barrier abnormality in humans is unknown. We report here that the presence of FLG mutations in Caucasians predicts dose-dependent alterations in epidermal permeability barrier function. Although FLG is an intracellular protein, the barrier abnormality occurred solely via a paracellular route in affected stratum corneum. Abnormal barrier function correlated with alterations in keratin filament organization (perinuclear retraction), impaired loading of lamellar body contents, followed by nonuniform extracellular distribution of secreted organelle contents, and abnormalities in lamellar bilayer architecture. In addition, we observed reductions in corneodesmosome density and tight junction protein expression. Thus, FLG deficiency provokes alterations in keratinocyte architecture that influence epidermal functions localizing to the extracellular matrix. These results clarify how FLG mutations impair epidermal permeability barrier function.
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Affiliation(s)
- Robert Gruber
- Department of Dermatology, Innsbruck Medical University, Innsbruck, Austria
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Abstract
Epithelia are found at the interfaces between body compartments where they act as selective permeability barriers that maintain the unique composition of the compartments on either side. Epithelial barrier function is dependent on tight junctions (TJs), which seal the intercellular or paracellular spaces but may permit selective permeability. In simple epithelia (one cell thick), the function of TJs is relatively well understood. By contrast, our understanding of TJ structure and function in stratified epithelia (e.g. the epidermis) is limited. This article briefly discusses what is known about TJs and their components in simple epithelia and speculates about their roles in the epidermis.
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Affiliation(s)
- Catherine A O'Neill
- Epithelial Sciences Research Group, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK.
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15
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Naumann A, Söderhäll C, Fölster-Holst R, Baurecht H, Harde V, Müller-Wehling K, Rodríguez E, Ruether A, Franke A, Wagenpfeil S, Novak N, Mempel M, Kalali BN, Allgaeuer M, Koch J, Gerhard M, Melén E, Wahlgren CF, Kull I, Stahl C, Pershagen G, Lauener R, Riedler J, Doekes G, Scheynius A, Illig T, von Mutius E, Schreiber S, Kere J, Kabesch M, Weidinger S. A comprehensive analysis of the COL29A1 gene does not support a role in eczema. J Allergy Clin Immunol 2011; 127:1187-94.e7. [DOI: 10.1016/j.jaci.2010.12.1123] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 12/16/2010] [Accepted: 12/27/2010] [Indexed: 01/09/2023]
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16
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Rodríguez E, Eyerich K, Weidinger S. Genetik häufiger chronisch-entzündlicher Hauterkrankungen. Hautarzt 2011; 62:107-18. [DOI: 10.1007/s00105-010-2053-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Chatterjea SM, Resing KA, Old W, Nirunsuksiri W, Fleckman P. Optimization of filaggrin expression and processing in cultured rat keratinocytes. J Dermatol Sci 2011; 61:51-9. [PMID: 21146962 PMCID: PMC3031422 DOI: 10.1016/j.jdermsci.2010.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 10/11/2010] [Accepted: 11/06/2010] [Indexed: 12/11/2022]
Abstract
BACKGROUND In normal mammalian epidermis, cell division occurs primarily in the basal layer where cells are attached to the basement membrane. Upon release from the basement membrane, these basal cells stop dividing and begin to differentiate and stratify producing cornified cells expressing differentiation markers, including the keratin bundling protein filaggrin, and cornified envelope proteins. Little is understood about the regulatory mechanisms of these processes. A rat epidermal keratinocyte cell line synthesizing and processing profilaggrin at confluence in a synchronous manner for 4-5 days provides a useful culture model for epidermal differentiation. Profilaggrin expression in this cell line however decreases with passaging, and its processing involves extensive nonspecific proteolysis. OBJECTIVE Our objective was to identify culture conditions that effect the decrease in profilaggrin expression with passaging and nonspecific proteolysis of profilaggrin in order to study epidermal differentiation more closely. METHOD The large amount of nonspecific proteolysis suggested autophagocytosis. To test this, cells were cultured in the presence of 3-methyladenine (3-MA). Two known gradients in epidermis are decreasing serum components and increasing calcium concentrations in the upper cell layers. To determine whether these gradients effected processing, cells were cultured in serum/DMEM or in serum-free KGM and under varying external calcium concentrations. Cells were also cultured in presence of aminoguanidine in an attempt to maintain profilaggrin expression with passaging. RESULTS Profilaggrin expression was enhanced in the presence of 3-MA, with optimum around 6mM. In the absence of aminoguanidine, profilaggrin expression decreased as a function of increasing passage number; in its presence, profilaggrin expression remained high in some, but not in all of the independently maintained cell lines. Thus, culturing in aminoguanidine was necessary, but not sufficient, for sustained ability to express profilaggrin at confluence. Production of filaggrin from profilaggrin was maximized in a serum-free medium with [Ca(2+)] at 5mM. Filaggrin associates with phospholipid vesicles in vitro forming aggregates similar to those seen in vivo, suggesting that filaggrin release induces vesicular aggregation and autophagocytosis. CONCLUSION We have used a keratinocyte cell line that synthesizes and processes profilaggrin after confluence as a culture model to study epidermal differentiation. In this system profilaggrin processing must be preceded by inhibition of autophagosome formation and/or modulation of vesicular trafficking, and these processes are regulated by epidermal calcium and serum factor gradients.
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Affiliation(s)
| | - Katheryn A. Resing
- Dept. of Chemistry & Biochemistry, University of Colorado at Boulder, Boulder CO, 80309
| | - William Old
- Dept. of Chemistry & Biochemistry, University of Colorado at Boulder, Boulder CO, 80309
| | | | - Philip Fleckman
- Division of Dermatology, University of Washington, Seattle WA, 98195
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Jungersted JM, Scheer H, Mempel M, Baurecht H, Cifuentes L, Høgh JK, Hellgren LI, Jemec GBE, Agner T, Weidinger S. Stratum corneum lipids, skin barrier function and filaggrin mutations in patients with atopic eczema. Allergy 2010; 65:911-8. [PMID: 20132155 DOI: 10.1111/j.1398-9995.2010.02326.x] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Prior to the discovery of filaggrin (FLG) mutations, evidence for an impaired skin barrier in atopic dermatitis (AD) has been documented, and changes in ceramide profile, altered skin pH and increased trans-epidermal water loss (TEWL) in patients with AD have been reported. Until now, no studies have analysed stratum corneum (SC) lipids combined with skin barrier parameters in subjects of known FLG genotype. METHODS A cohort of 49 German individuals genotyped for the most common FLG mutations (R501X, 2282del4) had SC samples taken for lipid analysis by high-performance thin layer chromatography. In addition, TEWL, erythema, skin hydration and pH were measured. In 27 of the 49 individuals, a 24-h irritation patch test with sodium lauryl sulphate was performed. For the analysis, both the AD group and the control group were stratified by FLG mutation status (FLGmut/FLGwt). RESULTS In the FLGmut AD group, significantly lower levels of ceramide 4 and significantly higher levels of ceramide 7 were observed when compared to both healthy control groups. However, ceramide 7 levels also significantly differed between FLGwt AD and FLGwt controls, as did ceramide 1 levels. No significant differences were observed for ceramide 2, 3, 5 and 6. FLGmut individuals had significantly higher skin pH values than individuals not carrying FLG mutations. Patients with AD with FLG mutations had significantly higher erythema compared to patients with AD without FLG mutations. CONCLUSION Our results confirm previous observations of altered ceramide levels in AD, which however appear to show no clear relationship with FLG mutations.
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Affiliation(s)
- J M Jungersted
- Department of Dermatology, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark.
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Cramer C, Link E, Horster M, Koletzko S, Bauer CP, Berdel D, von Berg A, Lehmann I, Herbarth O, Borte M, Schaaf B, Behrendt H, Chen CM, Sausenthaler S, Illig T, Wichmann HE, Heinrich J, Krämer U. Elder siblings enhance the effect of filaggrin mutations on childhood eczema: Results from the 2 birth cohort studies LISAplus and GINIplus. J Allergy Clin Immunol 2010; 125:1254-1260.e5. [DOI: 10.1016/j.jaci.2010.03.036] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/04/2010] [Accepted: 03/18/2010] [Indexed: 01/06/2023]
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Rodríguez E, Baurecht H, Herberich E, Wagenpfeil S, Brown SJ, Cordell HJ, Irvine AD, Weidinger S. Meta-analysis of filaggrin polymorphisms in eczema and asthma: robust risk factors in atopic disease. J Allergy Clin Immunol 2009; 123:1361-70.e7. [PMID: 19501237 DOI: 10.1016/j.jaci.2009.03.036] [Citation(s) in RCA: 280] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2009] [Revised: 03/21/2009] [Accepted: 03/24/2009] [Indexed: 12/20/2022]
Abstract
BACKGROUND The discovery of filaggrin (FLG) null mutations as a major risk factor for eczema represents a milestone toward the understanding of an important mechanism in this complex disease. However, published studies demonstrate differences concerning design and effect size, and conflicting results for asthma have been reported. OBJECTIVES We sought to provide a more accurate estimate of FLG effect sizes and to better refine FLG risk profiles within the broad and inclusive eczema diagnosis. We also sought to provide a more detailed and conclusive estimate of the risk for asthma associated with FLG null alleles. METHODS We performed a meta-analysis of 24 studies on FLG mutations and eczema involving 5,791 cases, 26,454 control subjects, and 1,951 families as well as 17 studies on asthma involving 3,138 cases, 17,164 control subjects, and 1,511 offspring. RESULTS Both case-control and family studies showed strong associations with eczema. Case-control studies were heterogeneous, whereas family studies yielded more homogeneous results. Combined analysis showed that FLG haploinsufficiency strongly increases the eczema risk (odds ratio [OR], 3.12; 95% CI, 2.57-3.79) and is associated with more severe and dermatologist-diagnosed disease. FLG mutations are also significantly associated with asthma (OR, 1.48; 95% CI, 1.32-1.66). However, although strong effects for the compound phenotype asthma plus eczema (OR, 3.29; 95% CI, 2.84-3.82) were observed, there appears to be no association with asthma in the absence of eczema. CONCLUSIONS This meta-analysis summarizes the strong evidence for a high eczema risk conferred by FLG mutations and refines their risk profiles, suggesting an association with more severe and secondary care disease. FLG mutations are also a robust risk factor for asthma and might help define the asthma endophenotype linked with eczema.
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Affiliation(s)
- Elke Rodríguez
- Division of Environmental Dermatology and Allergy, Helmholtz Zentrum Munich and ZAUM-Center for Allergy and Environment, Technische Universität München, Munich, Germany
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Brown SJ, Relton CL, Liao H, Zhao Y, Sandilands A, McLean WHI, Cordell HJ, Reynolds NJ. Filaggrin haploinsufficiency is highly penetrant and is associated with increased severity of eczema: further delineation of the skin phenotype in a prospective epidemiological study of 792 school children. Br J Dermatol 2009; 161:884-9. [PMID: 19681860 PMCID: PMC2883069 DOI: 10.1111/j.1365-2133.2009.09339.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Background Null mutations within the filaggrin gene (FLG) cause ichthyosis vulgaris and are associated with atopic eczema. However, the dermatological features of filaggrin haploinsufficiency have not been clearly defined. Objectives This study investigated the genotype–phenotype association between detailed skin phenotype and FLG genotype data in a population-based cohort of children. Methods Children (n= 792) aged 7–9 years were examined by a dermatologist. Features of ichthyosis vulgaris, atopic eczema and xerosis were recorded and eczema severity graded using the Three Item Severity score. Each child was genotyped for the six most prevalent FLG null mutations (R501X, 2282del4, R2447X, S3247X, 3702delG, 3673delC). Fisher’s exact test was used to compare genotype frequencies in phenotype groups; logistic regression analysis was used to estimate odds ratios and penetrance of the FLG null genotype and a permutation test performed to investigate eczema severity in different genotype groups. Results Ten children in this cohort had ichthyosis vulgaris, of whom five had mild–moderate eczema. The penetrance of FLG null mutations with respect to flexural eczema was 55·6% in individuals with two mutations, 16·3% in individuals with one mutation and 14·2% in wild-type individuals. Summating skin features known to be associated with FLG null mutations (ichthyosis, keratosis pilaris, palmar hyperlinearity and flexural eczema) showed a penetrance of 100% in children with two FLG mutations, 87·8% in children with one FLG mutation and 46·5% in wild-type individuals (P< 0·0001, Fisher exact test). FLG null mutations were associated with more severe eczema (P= 0·0042) but the mean difference was only 1–2 points in severity score. Three distinct patterns of palmar hyperlinearity were observed and these are reported for the first time. Conclusions Filaggrin haploinsufficiency appears to be highly penetrant when all relevant skin features are included in the analysis. FLG null mutations are associated with more severe eczema, but the effect size is small in a population setting.
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Affiliation(s)
- S J Brown
- Department of Dermatology, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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Weidinger S, Baurecht H, Wagenpfeil S, Henderson J, Novak N, Sandilands A, Chen H, Rodriguez E, O'Regan GM, Watson R, Liao H, Zhao Y, Barker JNWN, Allen M, Reynolds N, Meggitt S, Northstone K, Smith GD, Strobl C, Stahl C, Kneib T, Klopp N, Bieber T, Behrendt H, Palmer CNA, Wichmann HE, Ring J, Illig T, McLean WHI, Irvine AD. Analysis of the individual and aggregate genetic contributions of previously identified serine peptidase inhibitor Kazal type 5 (SPINK5), kallikrein-related peptidase 7 (KLK7), and filaggrin (FLG) polymorphisms to eczema risk. J Allergy Clin Immunol 2008; 122:560-8.e4. [PMID: 18774391 DOI: 10.1016/j.jaci.2008.05.050] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 04/28/2008] [Accepted: 05/23/2008] [Indexed: 01/27/2023]
Abstract
BACKGROUND Polymorphisms in the serine protease inhibitor gene serine peptidase inhibitor Kazal type 5 (SPINK5) and the serine protease kallikrein-related peptidase 7 gene (KLK7) appear to confer risk to eczema in some cohorts, but these findings have not been widely replicated. These genes encode proteins thought to be involved in the regulation of posttranslation processing of filaggrin (FLG), the strongest identified genetic risk factor for eczema to date. OBJECTIVES We sought to clarify the individual risk of eczema conferred by the SPINK5 polymorphism rs2303067 (Glu420Lys) and a previously described insertion in the 3' untranslated region of KLK7 and to examine potential epistatic effects between these variants and FLG mutations. METHODS Initially, we examined the effects of these polymorphisms and FLG in 486 unrelated patients from a German family-based study, an additional 287 German patients, and 418 unrelated Irish/English patients with eczema (n for 3 genes studied = 1191 vs 4544 control subjects). We then additionally studied the SPINK5 polymorphism and FLG mutations in 1583 patients with eczema from the Avon Longitudinal Study of Parents and Children cohort (sample size for 2 genes studied = 2774 vs 10,607 control subjects). RESULTS No association was seen with the SPINK5 or KLK7 variants in the case-control analysis; however, a weaker effect was observed for the SPINK5 variant with maternal transmission in the family-based study. No interactions were seen between the polymorphisms in KLK7, SPINK5, and FLG. CONCLUSION The SPINK5 420LysSer mutation confers a risk of eczema when maternally inherited but is not a major eczema risk factor. The KLK7 insertion appears to confer no risk of eczema. We found no interaction between the SPINK5 risk allele or the putative KLK7 risk allele and FLG mutations.
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Affiliation(s)
- Stephan Weidinger
- Department of Dermatology and Allergy Biederstein, Technical University Munich, Munich, Germany.
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