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Epigenetic regulation of skin: focus on the Polycomb complex. Cell Mol Life Sci 2012; 69:2161-2172. [PMID: 22314499 DOI: 10.1007/s00018-012-0920-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/25/2011] [Accepted: 01/09/2012] [Indexed: 12/17/2022]
Abstract
Chromatin regulators have recently emerged as key players in the control of tissue development and tumorigenesis. One specific chromatin regulator, the Polycomb complex, has been shown to regulate the identity of embryonic stem cells, but its role in controlling fates of multipotent progenitors in developing tissues is still largely unknown. Recent findings have revealed that this complex plays a critical role in control of skin stem cell renewal and differentiation. Moreover, the expression of Polycomb complex components is often aberrant in skin diseases, including skin cancers. This review will detail recent findings on Polycomb control of skin and highlight critical unknown questions.
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Identification of chromosome abnormalities in screening of a family with manic depression and psoriasis: predisposition to aneuploidy. Asian J Psychiatr 2012; 5:169-74. [PMID: 22813662 DOI: 10.1016/j.ajp.2012.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 11/21/2022]
Abstract
Cytogenetic analysis is an important stage in understanding the genetic background of manic depression (MD), and may provide a valuable clue to the identification of target loci and successful search for major genes. In order to identify chromosomal regions we aimed to detect the relationships between chromosomal aberrations (CAs) and immunological markers in a family with MD and psoriasis. We used the cell cultivation and conventional G-banding. We found predominantly numerical aberrations. The most common aneuploidy was chromosome 8, followed by chromosome 22, 21, 15, X and Y. However, structural aberrations consisted of duplications, deletions, translocations and breaks, with a focus on: loci on del(1)(q12-q23), del(1)(q21.1-q24), del(1)(q21.1-q23), del(10)(p11.2-pter), der(2)t(2;4)(p25;p12), t(2;22)(p14;p13), t(19;Y)? and dup(10)(q26). The susceptibility genes of MD or psoriasis may be located on these loci. Numerical sex CAs included 4(5.8%) with 45,X, 3(4.3%) with 47,XXY, and 4(5.8%) with structural chromosome X; del(X)(q13); del(X)(p11-pter) del(X)(q21.3) and inv(Y)(q11.2). We also conducted an immunological study. According results of this study, the percentage of CD2+, CD4+ and CD8+ lymphocytes of the father were significantly higher, whereas CD4+ lymphocytes were decreased in the mother, when compared the healthy persons. The percentage of CD4 level of the son was decreased, whereas CD8+ lymphocytes were higher. The CD4/CD8 ratio of the father and the son was found to be significantly high. These results may suggest that MD and psoriasis have a significant impact on both genetic and immunological parameters.
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Fuiano N, Incorvaia C. Dissecting the causes of atopic dermatitis in children: less foods, more mites. Allergol Int 2012; 61:231-43. [PMID: 22361514 DOI: 10.2332/allergolint.11-ra-0371] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/07/2011] [Indexed: 12/16/2022] Open
Abstract
Atopic dermatitis (AD) is a common, chronic or chronically relapsing, multifactorial skin disease that mainly occurs in children but affects also adults. AD usually begins early in life and often concerns people with a personal or family history of asthma and allergic rhinitis. AD is characterized by eczematous changes in the epidermis and originates from a late, T-cell mediated reaction associated to the formation and production of memory T-cell of TH2 type, occurrence of homing receptor at skin level and cutaneous lymphocyte-associated (CLA) antigens. Extrinsic or allergic AD, but not intrinsic AD, shows high total serum IgE levels and the presence of specific IgE for environmental and food allergens. A pivotal role in the pathogenesis of AD is played by filaggrin, a protein contained in the granular layer of the epidermis regulating the aggregation of keratin filaments. Mutation in the filaggrin gene causes decreased barrier function of the corny layers of the epidermis. This favours the enter through the skin of environmental allergens, especially the house dust mite, that further facilitates such entering by the proteolytic activity of its major allergen Der p 1. In fact, recent advances suggest that the dust mite, more than foods, is the major cause of allergic AD. As far as the causal diagnosis of AD is concerned, there is notable evidence supporting the capacity of the atopy patch test (APT) to reproduce the pathophysiologic events of AD. This makes APT a valuable diagnostic tool for AD.
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MESH Headings
- Animals
- Antigens, Dermatophagoides/adverse effects
- Antigens, Dermatophagoides/immunology
- Arthropod Proteins/adverse effects
- Arthropod Proteins/immunology
- Child
- Cysteine Endopeptidases/adverse effects
- Cysteine Endopeptidases/immunology
- Dermatitis, Atopic/diagnosis
- Dermatitis, Atopic/etiology
- Dermatitis, Atopic/genetics
- Dermatitis, Atopic/immunology
- Filaggrin Proteins
- Gene-Environment Interaction
- Humans
- Hypersensitivity, Delayed/diagnosis
- Hypersensitivity, Delayed/etiology
- Hypersensitivity, Delayed/genetics
- Hypersensitivity, Delayed/immunology
- Immunologic Memory
- Intermediate Filament Proteins/genetics
- Mutation
- Patch Tests
- Pyroglyphidae/immunology
- Skin/immunology
- Th2 Cells/immunology
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Affiliation(s)
- Nicola Fuiano
- Pediatric Allergy Service, ASL FG, Torremaggiore, Italy.
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Kapila S, Hong E, Fischer G. A comparative study of childhood psoriasis and atopic dermatitis and greater understanding of the overlapping condition, psoriasis-dermatitis. Australas J Dermatol 2012; 53:98-105. [DOI: 10.1111/j.1440-0960.2012.00878.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Crack LR, Chan HW, McPherson T, Ogg GS. Identification of an immunodominant region of the major house dust mite allergen Der p 2 presented by common human leucocyte antigen alleles. Clin Exp Dermatol 2012; 37:266-76. [PMID: 22188309 DOI: 10.1111/j.1365-2230.2011.04227.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Better understanding of the relevance of the immune response to common environmental allergens, such as the major house dust mite (HDM) allergen Der p 2, requires characterization of constituent T-cell epitopes. AIM To identify CD4(+) T-cell epitopes within Der p 2 recognized by commonly expressed human leucocyte antigen (HLA) alleles. METHODS HLA-blocking antibodies, peptide pools and truncations were used in ELISpot assays to establish restricted T-cell epitopes. RESULTS People with and without atopic dermatitis have detectable Der p 2-specific T cells in the peripheral blood, which can proliferate in response to Der p 2 peptides. Interleukin-4-specific responses, both ex vivo and cultured to Der p 2 peptides, had a significant positive correlation with HDM-specific serum IgE. Within one pool of Der p 2 peptides, the 20mer D11 was found to induce multiple responses restricted through several alleles, including HLA-DPB1*0401 and HLA-DRB1*01. CONCLUSIONS We have identified an immunogenic region of Der p 2 presented by common HLA class II alleles, including the most commonly expressed HLA allele DPB1*0401. Identification of such epitopes may be of future value in peptide immunotherapeutic approaches.
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Affiliation(s)
- L R Crack
- MRC Human Immunology Unit, University of Oxford, Weatherall Institute of Molecular Medicine, Oxford, UK
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56
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Knosp CA, Johnston JA. Regulation of CD4+ T-cell polarization by suppressor of cytokine signalling proteins. Immunology 2012; 135:101-11. [PMID: 22044277 DOI: 10.1111/j.1365-2567.2011.03520.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Suppressors of cytokine signalling (SOCS) proteins are induced in responses to many stimuli and by binding to cytokine receptors and associated janus kinase (JAK) proteins, directly regulate the activation of the signal transducers and activators of transcription (STATs). STAT proteins regulate the expression of many genes required for the differentiation of various CD4(+) T helper cell lineages, and there is now accumulating evidence that SOCS also play essential roles in the regulation and maintenance of CD4(+) T-cell polarization. As it is now clear that CD4(+) T cells are more plastic than initially thought, it is of particular importance to understand the molecular mechanisms regulating CD4(+) T-cell differentiation. Here we review the current understanding of how STATs and SOCS act in concert to influence the polarization of CD4(+) T cells and highlight the relevance of this in disease.
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Affiliation(s)
- Camille A Knosp
- The Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, University Road, Belfast, Northern Ireland
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Abstract
The discovery, in 2006, that loss-of-function mutations in the filaggrin (FLG) gene are the cause of ichthyosis vulgaris-the most common disorder of keratinization-and also a strong genetic risk factor for atopic eczema, marked a significant breakthrough in the understanding of eczema pathogenesis. Subsequent investigations of the role of FLG-null mutations have identified a series of significant associations with atopic disease phenotypes, including atopic asthma, allergic rhinitis, and peanut allergy. However, many questions remain to be answered in relation to the precise mechanisms by which deficiency of an intracellular protein expressed primarily in the differentiating epidermis may contribute to the development of cutaneous and systemic pathology. This review aims to highlight the key milestones in filaggrin research over the past 25 years, to discuss the mechanistic, clinical, and therapeutic implications, and to consider possible future directions for ongoing investigation.
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Affiliation(s)
- Sara J Brown
- Dermatology and Genetic Medicine, Division of Molecular Medicine, University of Dundee, Dundee, UK
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Human polymorphisms as clinical predictors in leprosy. J Trop Med 2011; 2011:923943. [PMID: 22220182 PMCID: PMC3246779 DOI: 10.1155/2011/923943] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/11/2011] [Accepted: 10/20/2011] [Indexed: 12/26/2022] Open
Abstract
Genetic and serum markers in human host can predict leprosy susceptibility per se as well as be useful in classification and/or prediction of clinical variants and immunological responses in leprosy. Adequate and timely assessment of potential risks associated with these 38 host leprosy genes could diminish epidemiological burden and improve life quality of patients with this still prevalent mycobacterial disease.
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Winge M, Bilcha K, Liedén A, Shibeshi D, Sandilands A, Wahlgren CF, McLean W, Nordenskjöld M, Bradley M. Novel filaggrin mutation but no other loss-of-function variants found in Ethiopian patients with atopic dermatitis. Br J Dermatol 2011; 165:1074-80. [DOI: 10.1111/j.1365-2133.2011.10475.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Blume-Peytavi U, Wahn U. Optimizing the treatment of atopic dermatitis in children: a review of the benefit/risk ratio of methylprednisolone aceponate. J Eur Acad Dermatol Venereol 2011; 25:508-15. [PMID: 21492244 DOI: 10.1111/j.1468-3083.2010.03942.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atopic dermatitis (AD) is a chronic, recurring, pruritic, inflammatory skin condition which has its onset in early childhood in most cases. A stepped approach to therapy, starting with emollients and adding first mild and then more potent topical medications is recommended. For more than 50 years, topical corticosteroids (TCs) have been the gold standard in AD therapy. Increasingly potent TCs have tended to come with increasing risk of adverse events, however. Calculating the benefit/risk ratio [or therapeutic index (TIX)] for TCs when treating children and infants is more challenging in this population. Not only does their increased surface area to volume ratio as a result of their small size mean that they are likely to absorb a greater proportion of any active agent applied to their skin, but drug metabolism is slower than in adults and the systemic effects of corticosteroids are more pronounced (in particular reduction of serum cortisol levels through suppression of the hypothalamic-pituitary-adrenal axis). Unlike traditional TCs, topical calcineurin inhibitors are not associated with the systemic effects and have shown good efficacy in treating AD in children. Parental/Carer concerns about their long-term use can limit their acceptance for treatment in the paediatric population, however. Modifications to the structure of fourth generation corticosteroids mean that increased potency is not accompanied by increased risk of adverse events and hence they have an improved TIX. Methylprednisolone aceponate is a potent fourth generation corticosteroid which has demonstrated efficacy and safety in acute and maintenance programmes in infants and children. It is licenced for once-daily use, and is available in four formulations - ointment, fatty ointment, cream and milk, which combine with its improved TIX to meet the needs of young patients and their carers.
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Hofmann Bowman MA, Heydemann A, Gawdzik J, Shilling RA, Camoretti-Mercado B. Transgenic expression of human S100A12 induces structural airway abnormalities and limited lung inflammation in a mouse model of allergic inflammation. Clin Exp Allergy 2011; 41:878-89. [PMID: 21418345 PMCID: PMC3093439 DOI: 10.1111/j.1365-2222.2011.03714.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND The calcium-binding protein S100A12 is highly up-regulated in the serum and sputum of patients with allergic asthma and is suggested to be a biomarker and pathologic mediator of asthma. OBJECTIVE To test the role of S100A12 in mediating airway inflammation in a mouse model of allergic lung inflammation. METHODS Transgenic (TG) mice that express human S100A12 and wild-type (WT) littermates were sensitized and challenged with ovalbumin (OVA) and assessed for inflammation, lung structure, and function. RESULTS Following OVA sensitization and challenge, S100A12 TG mice showed reduced peribronchial and perivascular inflammation, mucus production, and eosinophilia as well as attenuated airway responsiveness to contractile agonist compared with WT sensitized and challenged animals. This is explained, at least in part, by remodelled airways in S100A12 TG mice with thinning of the airway smooth muscle. S100A12 exposure induced Fas expression and activation of caspase 3 in cultured airway smooth muscle cells, suggesting that airway smooth muscle abnormalities observed in S100A12 TG mice may be mediated through myocyte apoptosis. CONCLUSION AND CLINICAL RELEVANCE S100A12 is one of the most abundant proteins found in the airways of human asthmatics, and it was postulated that S100A12 could mediate the inflammatory process. Our study shows for the first time that TG expression of S100A12 in the lung of mice does not exacerbate lung inflammation in a model of OVA-induced allergic inflammation. We speculate that the high levels of S100/calgranulins found in bronchoalveolar lavage fluid of asthmatics and of OVA-treated TG S100A12 mice do not significantly mediate pulmonary inflammation.
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Affiliation(s)
- M A Hofmann Bowman
- Department of Medicine, Sections of Cardiology, The University of Chicago, Chicago, IL 60637, USA.
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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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Zhang H, Guo Y, Wang W, Shi M, Chen X, Yao Z. Mutations in the filaggrin gene in Han Chinese patients with atopic dermatitis. Allergy 2011; 66:420-7. [PMID: 21039602 DOI: 10.1111/j.1398-9995.2010.02493.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Recently, loss-of-function mutations in the filaggrin gene (FLG) have been identified as the cause of ichthyosis vulgaris (IV) and also predisposing factors for atopic dermatitis (AD) and AD-associated phenotypes. Until now, over thirty mutations in FLG have been identified in patients with IV and AD, but the FLG mutation spectrum is not clear for Chinese Han patients with AD. This study aimed to investigate the role of FLG mutations in AD and AD-associated phenotypes in a Chinese population. METHODS We carried out a comprehensive sequencing of the entire FLG coding region in 261 Han AD patients. RESULTS In our research, we identified ten novel mutations (R826X, 3222del4, R1140X, 4271delAA, Q1790X, 5757del4, 6834del5, 6950del8, S2706X and K4671X) and eight reported mutations (441delA, R501X, 3321delA, R1474X, Q2417X, E2422X, 7945delA and R4306X) in FLG. FLG mutations were present in 31.4% of our AD patients. Mutations 3321delA and K4671X, with a frequency of 14.6% and 9.2%, respectively, were two of the most common mutations in this AD cohort. FLG null alleles (compound genotypes) were significantly associated with AD (P < 0.001) and AD associated with food sensitization (P = 0.012). However, we did not observe a positive association between FLG mutations and other AD-associated phenotypes, including asthma, allergic rhinitis and elevated total serum IgE level. CONCLUSION Our study increases the total number of reported FLG mutations. Moreover, we further confirm that FLG mutations are strong predisposing factors for AD in Han Chinese.
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Affiliation(s)
- H Zhang
- Department of Dermatology, Xinhua Hospital, Shanghai, China
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64
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Biagini Myers JM, Khurana Hershey GK. Eczema in early life: genetics, the skin barrier, and lessons learned from birth cohort studies. J Pediatr 2010; 157:704-14. [PMID: 20739029 PMCID: PMC2957505 DOI: 10.1016/j.jpeds.2010.07.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 04/22/2010] [Accepted: 07/06/2010] [Indexed: 12/17/2022]
Abstract
Eczema is a chronic inflammatory disorder of the skin that affects up to 30% of children. It often afflicts infants in the first few months of life and can be the first indicator of the atopic march. Recent results from birth cohort studies have uncovered novel information regarding genetic and environmental factors that promote the development of eczema. Birth cohort studies provide an optimal study design to elucidate these associations and prospectively track longitudinal data including exposure assessment and health outcomes from birth into early life and childhood. This is especially relevant for eczema given the age specific emergence of this disease. In this review, we will provide a general overview of pediatric eczema and discuss the important findings in the literature with respect to genetics and environmental exposures, highlighting those derived from birth cohort studies. Additionally, we will review how these relate to the atopic march, the hygiene hypothesis and the integrity of the skin barrier.
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Affiliation(s)
| | - Gurjit K. Khurana Hershey
- Division of Asthma Research, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA, Division of Allergy and Immunology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
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66
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Braconi D, Bernardini G, Santucci A. Post-genomics and skin inflammation. Mediators Inflamm 2010; 2010:364823. [PMID: 20886018 PMCID: PMC2945662 DOI: 10.1155/2010/364823] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 08/22/2010] [Indexed: 01/26/2023] Open
Abstract
Atopic dermatitis and psoriasis are two chronic skin inflammatory diseases that have so far received a greater attention within the scientific community through different post-genomic approaches; on the contrary, acne, which is undoubtedly one of the most common skin disorders involving inflammatory processes, seems to be still quite neglected under the post-genomic point of view. In this paper, we will review how post-genomic technologies have provided new fundamental tools for the analysis of these three conditions and we will cast light on their potential in addressing future research challenges.
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Affiliation(s)
- Daniela Braconi
- Dipartimento di Biologia Molecolare, Università degli Studi di Siena, via Fiorentina 1, 53100 Siena, Italy
| | - Giulia Bernardini
- Dipartimento di Biologia Molecolare, Università degli Studi di Siena, via Fiorentina 1, 53100 Siena, Italy
| | - Annalisa Santucci
- Dipartimento di Biologia Molecolare, Università degli Studi di Siena, via Fiorentina 1, 53100 Siena, Italy
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Abstract
IMPORTANCE OF THE FIELD Atopic eczema (AE) is a chronic relapsing inflammatory skin condition and one of the most common, potentially debilitating diseases with increasing incidence. AREAS COVERED IN THIS REVIEW The complex etiology of AE with multiple systemic and local immunologic and inflammatory responses and interactions between susceptibility genes and environmental factors leading to defects in skin barrier function and eczematous skin lesions is presented. Knowledge of pathogenesis is important for understanding the more innovative treatment approaches discussed. WHAT THE READER WILL GAIN Basic therapy consists of hydrating topical treatment and avoidance of specific and unspecific provocation factors. For acute eczematous skin lesions, anti-inflammatory treatment consists mainly of topical glucocorticoids and topical calcineurin inhibitors (tacrolimus and pimecrolimus). Microbial colonization and superinfection may induce skin exacerbation, which can be treated by either topical or systemic antimicrobial treatment. Systemic anti-inflammatory therapy is limited to severe cases and consists of systemic steroids, cyclosporine A or mycophenolate mofetil. Novel anti-inflammatory concepts that go beyond corticosteroids are in the early phases of development. There are targeted therapeutic approaches, such as cytokine and chemokine modulators and it remains to be investigated how effective they will be and what side effects they may carry. TAKE HOME MESSAGE Existing treatment modalities such as barrier repair therapy, topical immunosuppressive agents, antiseptic treatment as well as systemic treatment options are discussed. The review aims to summarize the most recent findings of more innovative treatment approaches such as modulation of cytokines or chemokines, modulation of T-cell responses or anti-IgE therapy.
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68
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Das UN. Polyunsaturated fatty acids and atopic dermatitis. Nutrition 2010; 26:719-20. [DOI: 10.1016/j.nut.2010.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 03/31/2010] [Indexed: 01/30/2023]
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Rupec RA, Boneberger S, Ruzicka T. What is really in control of skin immunity: lymphocytes, dendritic cells, or keratinocytes? facts and controversies. Clin Dermatol 2010; 28:62-6. [PMID: 20082953 DOI: 10.1016/j.clindermatol.2009.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The pathophysiology of atopic dermatitis is still under discussion. Although it is widely accepted that environmental factors and a genetic predisposition are essential, the role of the innate and adaptive immune system and the functional cascade of the cells involved is still unclear. A concept that integrates all immune cells as equally essential has allure. In addition, barrier abnormalities due to mutations of the gene coding for filaggrin and down-regulation of antimicrobial peptides, such as LL-37 and beta-defensins 2 and 3, were very recently found to be relevant for the pathogenesis of atopic dermatitis.
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Affiliation(s)
- Rudolf A Rupec
- Department of Dermatology and Allergology, Ludwig-Maximilian-University, 80337 Munich, Germany.
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Yu B, Shao Y, Zhang J, Dong X, Liu W, Yang H, Liu L, Li M, Yue C, Fang Z, Zhang C, Hu X, Chen B, Wu Q, Chen Y, Zhang W, Wan J. Polymorphisms in human histamine receptor H4 gene are associated with atopic dermatitis. Br J Dermatol 2010; 162:1038-43. [DOI: 10.1111/j.1365-2133.2010.09675.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Barnes KC. An update on the genetics of atopic dermatitis: scratching the surface in 2009. J Allergy Clin Immunol 2010; 125:16-29.e1-11; quiz 30-1. [PMID: 20109730 DOI: 10.1016/j.jaci.2009.11.008] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 11/06/2009] [Accepted: 11/09/2009] [Indexed: 12/27/2022]
Abstract
A genetic basis for atopic dermatitis (AD) has long been recognized. Historic documents allude to family history of disease as a risk factor. Before characterization of the human genome, heritability studies combined with family-based linkage studies supported the definition of AD as a complex trait in that interactions between genes and environmental factors and the interplay between multiple genes contribute to disease manifestation. A summary of more than 100 published reports on genetic association studies through mid-2009 implicates 81 genes, in 46 of which at least 1 positive association with AD has been demonstrated. Of these, the gene encoding filaggrin (FLG) has been most consistently replicated. Most candidate gene studies to date have focused on adaptive and innate immune response genes, but there is increasing interest in skin barrier dysfunction genes. This review examines the methods that have been used to identify susceptibility genes for AD and how the underlying pathology of this disease has been used to select candidate genes. Current challenges and the potential effect of new technologies are discussed.
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Affiliation(s)
- Kathleen C Barnes
- Johns Hopkins Asthma & Allergy Center, 5501 Hopkins Bayview Circle, Room 3A.62, Baltimore, MD 21224, USA.
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de Guzman Strong C, Conlan S, Deming CB, Cheng J, Sears KE, Segre JA. A milieu of regulatory elements in the epidermal differentiation complex syntenic block: implications for atopic dermatitis and psoriasis. Hum Mol Genet 2010; 19:1453-60. [PMID: 20089530 DOI: 10.1093/hmg/ddq019] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Two common inflammatory skin disorders with impaired barrier, atopic dermatitis (AD) and psoriasis, share distinct genetic linkage to the Epidermal Differentiation Complex (EDC) locus on 1q21. The EDC is comprised of tandemly arrayed gene families encoding proteins involved in skin cell differentiation. Discovery of semi-dominant mutations in filaggrin (FLG) associated with AD and a copy number variation within the LCE genes associated with psoriasis provide compelling evidence for the role of EDC genes in the pathogenesis of these diseases. To date, little is known about the potentially complex regulatory landscape within the EDC. Here, we report a computational approach to identify conserved non-coding elements (CNEs) in the EDC queried for regulatory function. Coordinate expression of EDC genes during mouse embryonic skin development and a striking degree of synteny and linearity in the EDC locus across a wide range of mammalian (placental and marsupial) genomes suggests an evolutionary conserved regulatory milieu in the EDC. CNEs identified by comparative genomics exhibit dynamic regulatory activity (enhancer or repressor) in differentiating or proliferating conditions. We further demonstrate epidermal-specific, developmental in vivo enhancer activities (DNaseI and transgenic mouse assays) in CNEs, including one within the psoriasis-associated deletion, LCE3C_LCE3B-del. Together, our multidisciplinary study features a network of regulatory elements coordinating developmental EDC gene expression as an unexplored resource for genetic variants in skin diseases.
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Affiliation(s)
- Cristina de Guzman Strong
- Genetics and Molecular Biology Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
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73
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Farhi D, Taïeb A, Tilles G, Wallach D. The historical basis of a misconception leading to undertreating atopic dermatitis (eczema):facts and controversies. Clin Dermatol 2010; 28:45-51. [DOI: 10.1016/j.clindermatol.2009.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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74
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Akiyama M. FLG
mutations in ichthyosis vulgaris and atopic eczema: spectrum of mutations and population genetics. Br J Dermatol 2009; 162:472-7. [DOI: 10.1111/j.1365-2133.2009.09582.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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75
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Are we ready to downregulate mast cells? Curr Opin Immunol 2009; 21:708-14. [DOI: 10.1016/j.coi.2009.09.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 09/14/2009] [Accepted: 09/18/2009] [Indexed: 11/17/2022]
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76
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Fonacier LS, Dreskin SC, Leung DYM. Allergic skin diseases. J Allergy Clin Immunol 2009; 125:S138-49. [PMID: 19932921 DOI: 10.1016/j.jaci.2009.05.039] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 05/28/2009] [Accepted: 05/29/2009] [Indexed: 01/06/2023]
Abstract
The skin is one of the largest immunologic organs and is affected by both external and internal factors, as well as innate and adaptive immune responses. Many skin disorders, such as atopic dermatitis, contact dermatitis, urticaria, angioedema, psoriasis, and autoimmune blistering disorders, are immune mediated. Most of these diseases are chronic, inflammatory, and proliferative, in which both genetic and environmental factors play important roles. These immunologic mechanisms might have implications for potential targets of future therapeutic interventions.
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77
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Taylor JM, Street TL, Hao L, Copley R, Taylor MS, Hayden PJ, Stolper G, Mott R, Hein J, Moffatt MF, Cookson WOCM. Dynamic and physical clustering of gene expression during epidermal barrier formation in differentiating keratinocytes. PLoS One 2009; 4:e7651. [PMID: 19888454 PMCID: PMC2766255 DOI: 10.1371/journal.pone.0007651] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Accepted: 10/09/2009] [Indexed: 11/18/2022] Open
Abstract
The mammalian epidermis is a continually renewing structure that provides the interface between the organism and an innately hostile environment. The keratinocyte is its principal cell. Keratinocyte proteins form a physical epithelial barrier, protect against microbial damage, and prepare immune responses to danger. Epithelial immunity is disordered in many common diseases and disordered epithelial differentiation underlies many cancers. In order to identify the genes that mediate epithelial development we used a tissue model of the skin derived from primary human keratinocytes. We measured global gene expression in triplicate at five times over the ten days that the keratinocytes took to fully differentiate. We identified 1282 gene transcripts that significantly changed during differentiation (false discovery rate <0.01%). We robustly grouped these transcripts by K-means clustering into modules with distinct temporal expression patterns, shared regulatory motifs, and biological functions. We found a striking cluster of late expressed genes that form the structural and innate immune defences of the epithelial barrier. Gene Ontology analyses showed that undifferentiated keratinocytes were characterised by genes for motility and the adaptive immune response. We systematically identified calcium-binding genes, which may operate with the epidermal calcium gradient to control keratinocyte division during skin repair. The results provide multiple novel insights into keratinocyte biology, in particular providing a comprehensive list of known and previously unrecognised major components of the epidermal barrier. The findings provide a reference for subsequent understanding of how the barrier functions in health and disease.
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Affiliation(s)
| | - Teresa L. Street
- Oxford Centre for Gene Function, Department of Statistics, University of Oxford, Oxford, England
| | - Lizhong Hao
- National Heart and Lung Institute, Imperial College, London, England
| | - Richard Copley
- Wellcome Trust Centre for Human Genetics, Oxford, England
| | | | - Patrick J. Hayden
- MatTek Corporation, Ashland, Massachusetts, United States of America
| | - Gina Stolper
- MatTek Corporation, Ashland, Massachusetts, United States of America
| | - Richard Mott
- Wellcome Trust Centre for Human Genetics, Oxford, England
| | - Jotun Hein
- Oxford Centre for Gene Function, Department of Statistics, University of Oxford, Oxford, England
| | - Miriam F. Moffatt
- National Heart and Lung Institute, Imperial College, London, England
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78
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Komine M. Analysis of the mechanism for the development of allergic skin inflammation and the application for its treatment:keratinocytes in atopic dermatitis - their pathogenic involvement. J Pharmacol Sci 2009; 110:260-4. [PMID: 19609063 DOI: 10.1254/jphs.09r06fm] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Atopic dermatitis frequently accompanies bronchial asthma, allergic rhinitis, and allergic conjunctivitis, the pathogenesis of which has frequently focused on the immunological aspects; however, skin eruption in atopic dermatitis occurs mainly in the epidermis, whose barrier function and cytokine expression have been revealed to be abnormal. In addition, the epidermis contains Langerhans cells, antigen-presenting cells, which could be considered the sentinel of the immune system. Some atopic dermatitis patients have been revealed to have mutations or SNPs (single-nucleotide polymorphisms) in the filaggrin gene, which affect the epidermal barrier function. Proteinases in the epidermis are of importance in maintaining the epidermal barrier, abnormalities of which have been reported in atopic dermatitis. Abnormalities of various cytokines and chemokines produced by keratinocytes have also been reported. Thymic stromal lymphopoietin (TSLP) produced by keratinocytes has recently been a focus in atopic dermatitis. Adrenergic/cholinergic responses in the epidermis could also influence the pathogenesis of atopic dermatitis. Considering epidermal keratinocytes as a trigger of immune abnormalities, not only as a peripheral effector, would be important to further disclose the pathogenesis of this enigmatic disorder.
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Affiliation(s)
- Mayumi Komine
- Department of Dermatology, Jichi Medical University, Japan.
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79
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Van Limbergen J, Russell RK, Nimmo ER, Zhao Y, Liao H, Drummond HE, Davies G, Gillett PM, McGrogan P, Bisset WM, Mahdi G, Wilson DC, Brown SJ, McLean WHI, Satsangi J. Filaggrin loss-of-function variants are associated with atopic comorbidity in pediatric inflammatory bowel disease. Inflamm Bowel Dis 2009; 15:1492-8. [PMID: 19408338 DOI: 10.1002/ibd.20926] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Pediatric inflammatory bowel disease (IBD) has a high prevalence of coexistent atopy. Filaggrin (FLG) loss-of-function variants (null-alleles) are associated with eczema and asthma in association with eczema. The aim was to assess the contribution of FLG null-alleles to pediatric IBD susceptibility and to coexistent atopy (eczema, asthma, allergic rhinitis, or food allergy). METHODS FLG variants (R501X and 2282del4) were genotyped in 403 children with IBD, 683 parents, and 996 population controls. RESULTS In all, 11% of IBD patients carried at least 1 FLG null-allele compared to 11% of population controls (P > 0.4). Carriage of 1 or more null-alleles in patients with atopy (present in 52% of IBD patients) differed from IBD patients without atopy (14% versus 6%, P = 0.01; odds ratio [OR] 2.4, 95% confidence interval [CI] 1.2-5.1). The effect of FLG null-alleles was strongest for eczema (19% versus 7%, P = 0.0003; OR 3.3, 95% CI 1.7-6.6) and food allergy (28% versus 8%, P = 0.0001; OR 4.5, 95% CI 2.0-10.0). The presence of more than 1 atopic disease tended to increase the associated OR: eczema + asthma (23% versus 7%, P = 0.001; OR 3.9, 95% CI 1.6-9.1), eczema + asthma + allergic rhinitis (29% versus 7%, P = 0.0006; OR 5.4, 95% CI 1.9-15.4) and eczema + asthma + allergic rhinitis + food allergy (45% versus 6%, P < 10(-4); OR 12.2, 95% CI 3.2-46.3). Logistic regression analysis of IBD cases confirmed the association of carriage of an FLG null-allele with atopy (P = 0.01; OR 2.4, 95% CI 1.2-5.1) and co-occurrence of different forms of atopy (P = 0.003; OR 3.5, 95% CI 1.5-8.1). CONCLUSIONS Filaggrin null-alleles have no effect on IBD susceptibility but contribute to coexistent eczema and food allergy.
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Affiliation(s)
- J Van Limbergen
- Molecular Medicine Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.
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80
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Stemmler S, Nothnagel M, Parwez Q, Petrasch-Parwez E, Epplen JT, Hoffjan S. Variation in genes of the epidermal differentiation complex in German atopic dermatitis patients. Int J Immunogenet 2009; 36:217-22. [PMID: 19601998 DOI: 10.1111/j.1744-313x.2009.00858.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The filaggrin (FLG) gene is one of the most widely replicated susceptibility genes for atopic dermatitis (AD) so far. Yet, FLG mutations cannot fully account for the original linkage peak on chromosome 1q21, a region comprising the so-called epidermal differentiation complex (EDC). Since the EDC contains numerous genes relevant for epidermal differentiation, we sought to evaluate variation in other genes located in this region in a German AD case-control cohort. Thirty-two single nucleotide polymorphisms (SNPs) in 21 genes across the EDC were genotyped in 402 unrelated AD patients and 325 non-atopic controls by means of restriction enzyme digestion or TaqMan assays. Allele and genotype frequencies were tested for differences between patients and controls by logistic regression. Haplotype frequencies were evaluated using the famhap software. Except for the already known association with FLG, we did not identify any additional significant associations of EDC genes with AD. Thus, in this German cohort, there is no evidence that additional genes in the EDC region apart from FLG contribute substantially to AD pathogenesis.
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Affiliation(s)
- S Stemmler
- Department of Human Genetics, Ruhr University, Universitätsstrasse 150, Bochum, Germany.
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81
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Sandilands A, Sutherland C, Irvine AD, McLean WHI. Filaggrin in the frontline: role in skin barrier function and disease. J Cell Sci 2009; 122:1285-94. [PMID: 19386895 DOI: 10.1242/jcs.033969] [Citation(s) in RCA: 533] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Recently, loss-of-function mutations in FLG, the human gene encoding profilaggrin and filaggrin, have been identified as the cause of the common skin condition ichthyosis vulgaris (which is characterised by dry, scaly skin). These mutations, which are carried by up to 10% of people, also represent a strong genetic predisposing factor for atopic eczema, asthma and allergies. Profilaggrin is the major component of the keratohyalin granules within epidermal granular cells. During epidermal terminal differentiation, the approximately 400 kDa profilaggrin polyprotein is dephosphorylated and rapidly cleaved by serine proteases to form monomeric filaggrin (37 kDa), which binds to and condenses the keratin cytoskeleton and thereby contributes to the cell compaction process that is required for squame biogenesis. Within the squames, filaggrin is citrullinated, which promotes its unfolding and further degradation into hygroscopic amino acids, which constitute one element of natural moisturising factor. Loss of profilaggrin or filaggrin leads to a poorly formed stratum corneum (ichthyosis), which is also prone to water loss (xerosis). Recent human genetic studies strongly suggest that perturbation of skin barrier function as a result of reduction or complete loss of filaggrin expression leads to enhanced percutaneous transfer of allergens. Filaggrin is therefore in the frontline of defence, and protects the body from the entry of foreign environmental substances that can otherwise trigger aberrant immune responses.
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Affiliation(s)
- Aileen Sandilands
- Epithelial Genetics Group, Division of Molecular Medicine, Colleges of Life Sciences and Medicine, Dentistry and Nursing, University of Dundee, Dundee DD1 5EH, UK
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82
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Abstract
The field of asthma genetics has progressed rapidly over the past decade, implicating many genes and variants in the etiology of this complex disease. However, many of these factors have failed to replicate consistently, indicating a high false-positive rate and/or insufficient power for the detection of small effects. Technological limitations also have restricted the potential to detect novel mechanisms, fostering a dependence on existing knowledge. Since its inception almost 4 years ago, genome-wide association (GWA) has transformed genetic studies of multifactorial traits and yielded unprecedented insights into mechanisms of causation. Asthma is at the forefront of this revolution, as it uses GWA to map not only genetic determinants of clinical status but also transcript and protein abundance and structural (copy number) variants that may underlie disease susceptibility. In this review, we consider the applications of GWA data to asthma and describe the factors likely to influence the procedure's success.
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83
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Burgess JA, Lowe AJ, Matheson MC, Varigos G, Abramson MJ, Dharmage SC. Does eczema lead to asthma? J Asthma 2009; 46:429-36. [PMID: 19544160 DOI: 10.1080/02770900902846356] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The nature of the relationship between eczema, asthma, and allergic rhinitis has been controversial. It has been commonly held that these disorders, while sharing genetic and environmental risk factors, are unrelated disorders that may develop sequentially along an atopic pathway. Conversely, the link between eczema and these later-onset respiratory disorders may be causal. This review examines the relationship between eczema, asthma, and allergic rhinitis in the context of the atopic march, the skin barrier, and recent developments in eczema genetics; and we propose that the relationship is causal. We describe a plausible biological pathway with eczema as the first step in a progressive atopic march that over time leads to asthma and/or allergic rhinitis. Such a pathway has implications for our understanding of these disorders and steps that might be made to prevent the development of asthma in particular. We propose that intervention studies in eczema should be conducted to confirm or refute this causal relationship. Such studies may materially improve the quality of life of eczema patients and will have important public health benefits if the interventions lead to a reduction in the burden of asthma.
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Affiliation(s)
- John A Burgess
- Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, The University of Melbourne, Carlton, Victoria, Australia.
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84
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Clark GJ, Ju X, Azlan M, Tate C, Ding Y, Hart DNJ. The CD300 molecules regulate monocyte and dendritic cell functions. Immunobiology 2009; 214:730-6. [PMID: 19592130 DOI: 10.1016/j.imbio.2009.06.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The CD300 glycoproteins are a family of related leucocyte surface molecules that modulate a diverse array of cell processes via their paired triggering and inhibitory receptor functions. All family members have a single Ig-V like domain and they share a common evolutionary pathway. At least one member of the family has undergone significant positive selection (ranked second in the top 50) indicating a need to maintain some crucial function. Here we have reviewed the CD300 family members, and their expression on cells of the monocyte and dendritic cell lineages. The consequences of CD300 molecule expression by these leucocyte lineages are only now beginning to be understood. The ability to fine tune monocyte and dendritic cell function and immune responses highlights several potential options to exploit these molecules as therapeutic targets in chronic inflammatory diseases, allergy and other disease states.
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Affiliation(s)
- Georgina J Clark
- Mater Medical Research Institute, South Brisbane, Queensland, Australia.
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85
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An association study of 22 candidate genes in psoriasis families reveals shared genetic factors with other autoimmune and skin disorders. J Invest Dermatol 2009; 129:2637-45. [PMID: 19554025 DOI: 10.1038/jid.2009.157] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Psoriasis is a common inflammatory and hyperproliferative skin disease. Recent studies have reported that common genetic factors may underlie both skin and immune-mediated disorders. We hypothesized that such genes may be involved in susceptibility to psoriasis, and undertook an association analysis of 22 candidate genes in a set of French high-risk psoriasis families. One hundred fifty-three single-nucleotide polymorphisms (SNPs) were genotyped and the transmission of alleles in nuclear families was analyzed using the FBAT (family-based association test). To further investigate suggestive associations, LNM (logistic-normal models) and MQLS (modified quasi-likelihood score) methods, which take the whole pedigree structure information of families into consideration, were also applied. Our study supported the involvement of six candidate genes in susceptibility to psoriasis: SCL12A8, which belongs to the solute carrier gene family; FLG and TGM5, which are involved in epidermal differentiation; CARD15 and CYLD, which modulate the transcription factor NF-kB; and IL1RN, which encodes an IL receptor antagonist. Furthermore, we found evidence for interaction between the major risk allele, HLA-Cw6, and CARD15, CYLD, and TGM5 susceptibility alleles. Taken together, our data show that shared genetic factors may contribute to the etiology of both psoriasis and other skin or immune-mediated disorders.
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86
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Linkage of atopic dermatitis to chromosomes 4q22, 3p24 and 3q21. Hum Genet 2009; 126:549-57. [PMID: 19517137 DOI: 10.1007/s00439-009-0692-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 05/25/2009] [Indexed: 10/20/2022]
Abstract
Atopic dermatitis (AD) is a common, itchy skin disease of complex inheritance characterized by dermal and epidermal inflammation. The heritability is considerable and well documented. To date, four genome scans have examined the AD phenotype, showing replicated linkage at 3p26-22, 3q13-21 and 18q11-21. Our previous AD scan showed evidence of linkage to loci at 3p and 18q, and furthermore at 4p15-14. In order to further investigate the genetic basis of AD, we collected and analysed a new Danish family sample consisting of 130 AD sib pair families (555 individuals including 295 children with AD). AD was diagnosed after clinical examination, AD severity was scored and specific IgE was determined. A linkage scan of chromosome 3, 4 and 18 was performed using 91 microsatellite markers. Linkage analyses were performed of dichotomous phenotypes and semi-quantitative traits including the AD severity score. We analysed the novel AD sample alone and together with the previously examined sample. AD severity showed a maximum Z-score of 3.7 at 4q22.1 suggesting the localization of a novel gene for AD severity. A maximum MOD score of 4.6 was obtained at 3p24 for the AD phenotype, providing the first significant linkage of AD at this locus. A maximum MLS score of 3.3 was obtained at 3q21 for IgE-associated AD, and evidence of linkage was also obtained at 3p22.2-21.31, 3q13, 4q35, and 18q12. The results presented should provide a firm basis for gene-targeting studies of AD and related disorders.
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87
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Müller S, Marenholz I, Lee YA, Sengler C, Zitnik SE, Griffioen RW, Meglio P, Wahn U, Nickel R. Association of Filaggrin loss-of-function-mutations with atopic dermatitis and asthma in the Early Treatment of the Atopic Child (ETAC) population. Pediatr Allergy Immunol 2009; 20:358-61. [PMID: 19538357 DOI: 10.1111/j.1399-3038.2008.00808.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many candidate gene studies for atopic dermatitis (AD) and associated phenotypes have been conducted so far, but replication of significant results has been a major problem. Two loss of function polymorphisms FLG R501X- and 2282del4, in the Filaggrin (FLG) gene encoding for an epidermal barrier protein were recently identified. They were reported to be predisposing factors for AD and concomitant asthma. Several groups confirmed the initial results in independent populations. The aim of this study is to further investigate the importance of these FLG variants in the development of AD and subsequent asthma symptoms in pre-school children, we investigated children and parents of the Early Treatment of the Atopic Child (ETAC)-trial. We genotyped 496 children and 488 parents of the ETAC population for the two FLG variants, evaluating an association by family based analysis (transmission disequilibrium test). We found a highly significant association of the FLG null variants R501X- and 2282del4 with AD (combined genotype p < 0.0001) and asthma (combined genotype p < 0.0001). The replication and its statistical significance underlines the importance of the FLG polymorphisms and the importance of the skin barrier function in the development of AD and subsequent asthma.
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Affiliation(s)
- Sebastian Müller
- Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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88
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89
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The CD300 family of molecules are evolutionarily significant regulators of leukocyte functions. Trends Immunol 2009; 30:209-17. [PMID: 19359216 DOI: 10.1016/j.it.2009.02.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 02/16/2009] [Accepted: 02/17/2009] [Indexed: 11/23/2022]
Abstract
The CD300 glycoproteins are a family of cell surface molecules that modulate a diverse array of cell processes via their paired triggering and inhibitory receptor functions. Family members share a common evolutionary pathway and at least one member of the family has undergone significant positive selection, indicating their crucial value to the host. This review clarifies the occasionally confusing usage of nomenclature for the CD300 family and summarizes our current understanding of their genomics, expression and function. Their ability to fine tune leukocyte function and immune responses highlights several potential options to exploit the CD300 molecules as therapeutic targets in chronic inflammatory diseases, allergy and other disease states.
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90
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Pincelli C, Pignatti M, Borroni RG. Pharmacogenomics in dermatology: from susceptibility genes to personalized therapy. Exp Dermatol 2009; 18:337-49. [DOI: 10.1111/j.1600-0625.2009.00852.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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91
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92
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Abstract
Rapidly increasing knowledge on the complex background of atopic dermatitis (AD) on the genetic, immunological and environmental level in combination with the continuous improvement in our diagnostic options has initiated an ongoing discussion on factors, which primarily promote the disease on one hand and mechanisms which emerge rather secondarily as a consequence of disease-specific modifications, on the other hand. Beside a sustained search for reliable and meaningful diagnostic tools for elicitors of the disease, novel therapeutic approaches are required, as most of the treatments of AD are limited to symptomatic therapies. In contrast, therapeutic approaches selectively regulating aberrant pathophysiological mechanisms in AD itself would be much more effective and promising.
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Affiliation(s)
- N Novak
- Department of Dermatology and Allergy, University of Bonn, Bonn, Germany
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93
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Liedén A, Ekelund E, Kuo IC, Kockum I, Huang CH, Mallbris L, Lee SP, Seng LK, Chin GY, Wahlgren CF, Palmer CNA, Björkstén B, Ståhle M, Nordenskjöld M, Bradley M, Chua KY, D'Amato M. Cornulin, a marker of late epidermal differentiation, is down-regulated in eczema. Allergy 2009; 64:304-11. [PMID: 19133922 DOI: 10.1111/j.1398-9995.2008.01856.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Eczema is a common chronic inflammatory skin disorder which shows strong genetic predisposition. To identify new potential molecular determinants of the disease pathogenesis, we performed a gene expression study in an eczema mouse model. This analysis identified a marked down regulation of the cornulin gene (CRNN), a member of the epidermal differentiation complex, in the eczema-like skin. We then investigated CRNN as an eczema candidate gene and studied its polymorphism and the expression in the skin of eczema patients. METHODS An eczema-like phenotype was induced in mice by allergen (Der p2) patching. Gene expression analysis was performed with the subtractive suppression hybridization method and validated by real time PCR and the transmission disequilibrium test was used to test for genetic associations in 406 multiplex eczema families. RESULTS Der p 2 patched mice developed a localized eczema and a Th 2 skewed systemic response. Real time PCR analysis confirmed a down regulation of CRNN mRNA in eczema-like skin in the mouse model and in human eczema. The CRNN polymorphism rs941934 was significantly associated with atopic eczema in the genetic analysis (P = 0.006), though only as part of an extended haplotype including a known associated variant (2282del4) in the filaggrin gene. CONCLUSIONS CRNN mRNA expression is decreased in eczematous skin. Further studies are needed to verify whether the associated cornulin polymorphism contribute to the genetic susceptibility in eczema.
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Affiliation(s)
- A Liedén
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Oyoshi MK, He R, Kumar L, Yoon J, Geha RS. Cellular and molecular mechanisms in atopic dermatitis. Adv Immunol 2009; 102:135-226. [PMID: 19477321 DOI: 10.1016/s0065-2776(09)01203-6] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Atopic dermatitis (AD) is a pruritic inflammatory skin disease associated with a personal or family history of allergy. The prevalence of AD is on the rise and estimated at approximately 17% in the USA. The fundamental lesion in AD is a defective skin barrier that results in dry itchy skin, and is aggravated by mechanical injury inflicted by scratching. This allows entry of antigens via the skin and creates a milieu that shapes the immune response to these antigens. This review discusses recent advances in our understanding of the abnormal skin barrier in AD, namely abnormalities in epidermal structural proteins, such as filaggrin, mutated in approximately 15% of patients with AD, epidermal lipids, and epidermal proteases and protease inhibitors. The review also dissects, based on information from mouse models of AD, the contributions of the innate and adaptive immune system to the pathogenesis of AD, including the effect of mechanical skin injury on the polarization of skin dendritic cells, mediated by keratinocyte-derived cytokines such as thymic stromal lymphopoietin (TSLP), IL-6, and IL-1, that results in a Th2-dominated immune response with a Th17 component in acute AD skin lesions and the progressive conversion to a Th1-dominated response in chronic AD skin lesions. Finally, we discuss the mechanisms of susceptibility of AD skin lesions to microbial infections and the role of microbial products in exacerbating skin inflammation in AD. Based on this information, we discuss current and future therapy of this common disease.
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Affiliation(s)
- Michiko K Oyoshi
- Division of Immunology, Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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Sääf AM, Tengvall-Linder M, Chang HY, Adler AS, Wahlgren CF, Scheynius A, Nordenskjöld M, Bradley M. Global expression profiling in atopic eczema reveals reciprocal expression of inflammatory and lipid genes. PLoS One 2008; 3:e4017. [PMID: 19107207 PMCID: PMC2603322 DOI: 10.1371/journal.pone.0004017] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 11/18/2008] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Atopic eczema (AE) is a common chronic inflammatory skin disorder. In order to dissect the genetic background several linkage and genetic association studies have been performed. Yet very little is known about specific genes involved in this complex skin disease, and the underlying molecular mechanisms are not fully understood. METHODOLOGY/FINDINGS We used human DNA microarrays to identify a molecular picture of the programmed responses of the human genome to AE. The transcriptional program was analyzed in skin biopsy samples from lesional and patch-tested skin from AE patients sensitized to Malassezia sympodialis (M. sympodialis), and corresponding biopsies from healthy individuals. The most notable feature of the global gene-expression pattern observed in AE skin was a reciprocal expression of induced inflammatory genes and repressed lipid metabolism genes. The overall transcriptional response in M. sympodialis patch-tested AE skin was similar to the gene-expression signature identified in lesional AE skin. In the constellation of genes differentially expressed in AE skin compared to healthy control skin, we have identified several potential susceptibility genes that may play a critical role in the pathological condition of AE. Many of these genes, including genes with a role in immune responses, lipid homeostasis, and epidermal differentiation, are localized on chromosomal regions previously linked to AE. CONCLUSIONS/SIGNIFICANCE Through genome-wide expression profiling, we were able to discover a distinct reciprocal expression pattern of induced inflammatory genes and repressed lipid metabolism genes in skin from AE patients. We found a significant enrichment of differentially expressed genes in AE with cytobands associated to the disease, and furthermore new chromosomal regions were found that could potentially guide future region-specific linkage mapping in AE. The full data set is available at http://microarray-pubs.stanford.edu/eczema.
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Affiliation(s)
- Annika M Sääf
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
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97
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Abstract
The discovery that null mutations in the filaggrin gene (FLG) are associated with atopic eczema represents the single most significant breakthrough in understanding the genetic basis of this complex disorder. The association has been replicated in multiple independent studies during the past 2 years with the use of various methodologies, from populations in Europe, the United States, and Japan. Filaggrin plays a key role in epidermal barrier function, and its association with atopic eczema emphasizes the importance of barrier dysfunction in eczema pathogenesis. This review aims to summarize the current state of knowledge regarding the role of FLG mutations in ichthyosis vulgaris, atopic eczema, and other skin disorders, with an emphasis on potential clinical applications. Further research is needed to clarify the precise role of filaggrin in skin and systemic atopic disease, to pave the way for novel therapeutic interventions.
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Abstract
Atopic dermatitis is increasing in prevalence and currently affects 15–30% of children in urban areas. Immune dysregulation and an impaired epidermal barrier are important factors in the pathogenesis of this disease. Pruritus and a chronic relapsing remitting course are hallmarks of the disorder, and sleep disturbance can occur in both the patient and family. Preventive interventions include exclusive breastfeeding in the first 4 months of life and withholding solid foods for 6 months. The avoidance of irritants and the use of emollients decrease flares. Topical corticosteroids remain the mainstay of therapy, and should be judiciously utilized. Excessive and inappropriate use must be avoided, as well as ‘steroid phobia’. The topical calcineurin inhibitors can be useful adjuncts. Systemic therapies are available for severe disease, but carry risks of adverse effects.
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Affiliation(s)
- Joseph Lam
- Clinical Assistant Professor, Department of Pediatrics, University of British Columbia, School of Medicine, British Columbia, Vancouver, Canada
| | - Sheila F Friedlander
- Clinical Professor, Departments of Pediatrics & Medicine (Dermatology), University of California, San Diego School of Medicine, CA, USA
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Abstract
Psoriasis is a chronic, immune mediated inflammatory disease characterized by increased cell signalling via cytokines and chemokines on a background of up-regulated gene expression. There is substantial evidence that psoriasis should be regarded as more than a cutaneous disease; major psychological morbidity and increased mortality from cardiovascular disease and cancer are increasingly recognized. Improved understanding of the genetic and immunological mechanisms underpinning psoriasis has occurred concurrently with the development of targeted biological therapies including infliximab. These newer therapeutic approaches can be very effective but their long term safety profile is not yet fully determined.
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Affiliation(s)
- JA Leman
- Alan Lyell Centre for Dermatology, Western Infirmary, Glasgow, UK
| | - AD Burden
- Alan Lyell Centre for Dermatology, Western Infirmary, Glasgow, UK
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