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Abstract
PURPOSE Antimicrobial peptides (AMPs) and toll-like receptors (TLRs) form part of the "chemical barrier" of the ocular surface to microbes. Evidence suggests that pathogen recognition by TLR releases AMPs, altering AMP-TLR profiles in pathological states. This study investigated ocular surface expression of AMP-TLRs in health and disease. METHODS Complementary DNA from conjunctival and corneal impression cytology samples was used for semiquantitative and quantitative polymerase chain reactions, to determine gene expression of 6 AMPs and TLRs-1-10, in healthy subjects and patients with bacterial (n = 6), viral (n = 6), Acanthamoeba (n = 3), or dry eye (n = 7) diseases. RESULTS Semiquantitative polymerase chain reaction showed variable AMP expression within groups and some expression patterns between groups, increased levels of LEAP (liver-expressed antimicrobial peptide)-1/hepcidin in viral disease, LEAP-2 in dry eye, and human beta defensin 3 in bacterial disease. There was no significant variability in TLR expression. Quantitative polymerase chain reaction showed significantly higher expression of LEAP-1 (P = 0.002) and TLR-8 (P = 0.023) and TLR-10 (P = 0.014) in viral keratitis and LEAP-2 (P = 0.034) in dry eye, versus controls. CONCLUSIONS Increased expression of LEAP-1 and TLRs 8 and 10 in viral keratitis is novel; TLR-10 has not previously had a documented ligand. LEAP-2 may have a role in dry eye. Further studies will help to improve the understanding of these diseases and yield novel therapeutic interventions.
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102
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Platts-Mills TAE, Woodfolk JA. Allergens and their role in the allergic immune response. Immunol Rev 2011; 242:51-68. [PMID: 21682738 DOI: 10.1111/j.1600-065x.2011.01021.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Allergens are recognized as the proteins that induce immunoglobulin E (IgE) responses in humans. The proteins come from a range of sources and, not surprisingly, have many different biological functions. However, the delivery of allergens to the nose is exclusively on particles, which carry a range of molecules in addition to the protein allergens. These molecules include pathogen-associated molecular patterns (PAMPs) that can alter the response. Although the response to allergens is characterized by IgE antibodies, it also includes other isotypes (IgG, IgA, and IgG4), as well as T cells. The challenge is to identify the characteristics of these exposures that favor the production of this form of response. The primary features of the exposure appear to be the delivery in particles, such as pollen grains or mite feces, containing both proteins and PAMPs, but with overall low dose. Within this model, there is a simple direct relationship between the dose of exposure to mite or grass pollen and the prevalence of IgE responses. By contrast, the highest levels of exposure to cat allergen are associated with a lower prevalence of IgE responses. Although the detailed mechanisms for this phenomenon are not clear, it appears that enhanced production of interleukin-10 in response to specific Fel d 1 peptides could influence the response. However, it is striking that the animal sources that are most clearly associated with decreased responses at high allergen dose are derived from animals from which humans evolved more recently (∼65 million years ago). Although the nose is still recognized as the primary route for sensitization to inhalant allergens, there is increasing evidence that the skin is also an important site for the generation of IgE antibody responses. By contrast, it is now evident that delivery of foreign proteins by the oral route or sublingually will favor the generation of tolerance.
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Affiliation(s)
- Thomas A E Platts-Mills
- Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville, VA 22908-1355, USA.
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103
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Cholinergic regulation of keratinocyte innate immunity and permeability barrier integrity: new perspectives in epidermal immunity and disease. J Invest Dermatol 2011; 132:28-42. [PMID: 21918536 DOI: 10.1038/jid.2011.264] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Several cutaneous inflammatory diseases and their clinical phenotypes are recapitulated in animal models of skin disease. However, the identification of shared pathways for disease progression is limited by the ability to delineate the complex biochemical processes fundamental for development of the disease. Identifying common signaling pathways that contribute to cutaneous inflammation and immune function will facilitate better scientific and therapeutic strategies to span a variety of inflammatory skin diseases. Aberrant antimicrobial peptide (AMP) expression and activity is one mechanism behind the development and severity of several inflammatory skin diseases and directly influences the susceptibility of skin to microbial infections. Our studies have recently exposed a newly identified pathway for negative regulation of AMPs in the skin by the cholinergic anti-inflammatory pathway via acetylcholine (ACh). The role of ACh in AMP regulation of immune and permeability barrier function in keratinocytes is reviewed, and the importance for a better comprehension of cutaneous disease progression by cholinergic signaling is discussed.
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104
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Howell MD, Gao P, Kim BE, Lesley LJ, Streib JE, Taylor PA, Zaccaro DJ, Boguniewicz M, Beck LA, Hanifin JM, Schneider LC, Hata TR, Gallo RL, Kaplan MH, Barnes KC, Leung DYM. The signal transducer and activator of transcription 6 gene (STAT6) increases the propensity of patients with atopic dermatitis toward disseminated viral skin infections. J Allergy Clin Immunol 2011; 128:1006-14. [PMID: 21762972 DOI: 10.1016/j.jaci.2011.06.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 06/01/2011] [Accepted: 06/02/2011] [Indexed: 01/10/2023]
Abstract
BACKGROUND Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with increased susceptibility to recurrent skin infections. OBJECTIVE We sought to determine why a subset of patients with AD have an increased risk of disseminated viral skin infections. METHODS Human subjects with AD with a history of eczema herpeticum (EH) and various control groups were enrolled. Vaccinia virus (VV) expression was measured by means of PCR and immunofluorescent staining in skin biopsy specimens from each study group after incubation with VV. Transgenic mice with a constitutively active signal transducer and activator of transcription 6 gene (STAT6) were characterized for response to VV skin inoculation. Genotyping for 10 STAT6 single nucleotide polymorphisms (SNPs) was performed in a white patient sample (n = 444). RESULTS VV gene and protein expression were significantly increased in the skin of patients with EH compared with other subject groups after incubation with VV in vitro. Antibody neutralization of IL-4 and IL-13 resulted in lower VV replication in patients with a history of EH. Mice that expressed a constitutively active STAT6 gene compared with wild-type mice had increased mortality and satellite lesion formation after VV skin inoculation. Significant associations were observed between STAT6 SNPs and EH (rs3024975, rs841718, rs167769, and rs703817) and IFN-γ production. The strongest association was observed for a 2-SNP haplotype (patients with AD with a history of EH vs patients with AD without a history of EH, 24.9% vs 9.2%; P = 5.17 × 10(-6)). CONCLUSION The STAT6 gene increases viral replication in the skin of patients with AD with a history of EH. Further genetic association studies and functional investigations are warranted.
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Affiliation(s)
- Michael D Howell
- Department of Pediatrics, National Jewish Health, Denver, Colo 80206, USA
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105
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Guttman-Yassky E, Nograles KE, Krueger JG. Contrasting pathogenesis of atopic dermatitis and psoriasis—Part II: Immune cell subsets and therapeutic concepts. J Allergy Clin Immunol 2011; 127:1420-32. [DOI: 10.1016/j.jaci.2011.01.054] [Citation(s) in RCA: 195] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 12/27/2010] [Accepted: 01/05/2011] [Indexed: 01/19/2023]
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106
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Bernard JJ, Gallo RL. Protecting the boundary: the sentinel role of host defense peptides in the skin. Cell Mol Life Sci 2011; 68:2189-99. [PMID: 21573782 DOI: 10.1007/s00018-011-0712-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 04/26/2011] [Accepted: 04/26/2011] [Indexed: 10/18/2022]
Abstract
The skin is our primary shield against microbial pathogens and has evolved innate and adaptive strategies to enhance immunity in response to injury or microbial insult. The study of antimicrobial peptide (AMP) production in mammalian skin has revealed several of the elegant strategies that AMPs use to prevent infection. AMPs are inducible by both infection and injury and protect the host by directly killing pathogens and/or acting as multifunctional effector molecules that trigger cellular responses to aid in the anti-infective and repair response. Depending on the specific AMP, these molecules can influence cytokine production, cell migration, cell proliferation, differentiation, angiogenesis and wound healing. Abnormal production of AMPs has been associated with the pathogenesis of several cutaneous diseases and plays a role in determining a patient's susceptibility to pathogens. This review will discuss current research on the regulation and function of AMPs in the skin and in skin disorders.
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Affiliation(s)
- Jamie J Bernard
- Division of Dermatology, Department of Medicine, University of California, San Diego, San Diego, CA 92126, USA
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107
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Expresión diferencial en placenta de beta-defensinas humanas y detección de variantes alélicas en el gen DEFB1 de madres positivas para VIH-1. BIOMEDICA 2011. [DOI: 10.7705/biomedica.v31i1.335] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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108
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Persistent nasal carriage of Staphylococcus aureus is associated with deficient induction of human beta-defensin 3 after sterile wounding of healthy skin in vivo. Infect Immun 2011; 79:2658-62. [PMID: 21464083 DOI: 10.1128/iai.00101-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Persistent nasal carriage of Staphylococcus aureus is the primary reservoir for this pathogen and a risk factor for infection. The nares of 12 to 30% of healthy individuals are persistently colonized with staphylococci. Elucidating the yet enigmatic determinants of this phenomenon is of major public health interest. We hypothesized that differences in the levels of antimicrobial peptides (AMPs) that are found in human skin and have pronounced antistaphylococcal activity may contribute to this phenomenon. We compared constitutive and induced mRNA levels of RNase 7 and human β-defensin 3 (HBD-3) in healthy and experimentally wounded gluteal skin of 60 volunteers after ascertaining their carrier status through repeated nasal cultures. We found that levels of HBD-3 expression in skin of persistent nasal carriers of S. aureus were lower: induced levels in carriers were 63% (95% confidence interval, 43 to 94%; P = 0.02) and constitutive levels were 76% (95% confidence interval, 52 to 110%; P = 0.14) of those found in noncarriers. No such associations were present for RNase 7. In conjunction with existing knowledge, these findings suggest that healthy individuals with deficient HBD-3 expression in keratinocytes are more prone to persistent nasal colonization with S. aureus.
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Stefanaki C, Stefanaki I, Verra P, Hadjivassiliou M, Caroni C, Bethimoutis G, Papadogeorgaki H, Stavropoulos P, Kostaki M, Antoniou C, Katsambas A. Atopic patients with genital warts have a more protracted clinical course and a greater probability of recurrences. Int J STD AIDS 2011; 21:723-7. [PMID: 21139153 DOI: 10.1258/ijsa.2010.010225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The factors predicting an unfavourable response of genital warts to treatment have not been determined. The disease characteristics were recorded for 390 patients with genital warts and treated by cryotherapy. The time to achieve clearance was recorded. A personal and family history of asthma, hay fever or eczema, as well as a personal history of common warts and number of recurrences was obtained by telephone four to five years after the clinical visits. In multiple regression analysis, the number of lesions (P < 0.001), extent of the disease (P = 0.003) and personal history of atopy (P = 0.001) were found to influence the time until response to treatment. Similar results were obtained for family history of atopy. The number of sexual partners (P = 0.007), extent of the disease (P = 0.009) and personal history of atopy (P < 0.001) were the main factors influencing the probability of recurrence in multiple logistic regression. The results for family history of atopy were again similar. The study concludes that atopy is a major factor influencing the time frame of the therapeutic response and the probability of recurrence in patients with genital warts.
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Affiliation(s)
- C Stefanaki
- Sexually Transmitted Infections Unit, Dermatology Department, University of Athens, Andreas Sygros Hospital, Athens, Greece.
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Abstract
Host defence responses against invading pathogens are well-balanced, inflammatory processes of the innate and adaptive immune system. Impaired development or abnormal function of either system can result in failure to control pathogens and to clear infections. Infections have been claimed to modulate the onset and course of allergic diseases. This so-called hygiene hypothesis is still an active area of research. In contrast, the effects of allergies on infections and pathogen-directed immune responses are less well understood. Here, we have reviewed the existing evidence that allergies result in impaired innate immunity and we discuss recent observations that may explain why and how innate immunity is dysfunctional in allergic patients. With a focus on atopic dermatitis as a model of allergic disease, we speculate that one of the key features of allergic conditions, namely Th2 polarization, leads to several independent inhibitory effects on host defence and consequently to a higher risk of infections in allergic patients. A better understanding of impaired host defence and its mechanisms in allergic subjects will help to improve the management of these diseases.
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Affiliation(s)
- S Mrabet-Dahbi
- Department of Dermatology and Allergy, Charité-Universitätsmedizin Berlin, Berlin, Germany
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111
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Santoro D, Bunick D, Graves TK, Campbell KL. Expression and distribution of antimicrobial peptides in the skin of healthy beagles. Vet Dermatol 2010; 22:61-7. [DOI: 10.1111/j.1365-3164.2010.00911.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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112
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Lai Y, Cogen AL, Radek KA, Park HJ, Macleod DT, Leichtle A, Ryan AF, Di Nardo A, Gallo RL. Activation of TLR2 by a small molecule produced by Staphylococcus epidermidis increases antimicrobial defense against bacterial skin infections. J Invest Dermatol 2010; 130:2211-21. [PMID: 20463690 DOI: 10.1038/jid.2010.123] [Citation(s) in RCA: 275] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Production of antimicrobial peptides by epithelia is an essential defense against infectious pathogens. In this study we evaluated whether the commensal microorganism Staphylococcus epidermidis may enhance production of antimicrobial peptides by keratinocytes and thus augment skin defense against infection. Exposure of cultured undifferentiated human keratinocytes to a sterile nontoxic small molecule of <10 kDa from S. epidermidis conditioned culture medium (SECM), but not similar preparations from other bacteria, enhanced human beta-defensin 2 (hBD2) and hBD3 mRNA expression and increased the capacity of cell lysates to inhibit the growth of group A Streptococcus (GAS) and S. aureus. Partial gene silencing of hBD3 inhibited this antimicrobial action. This effect was relevant in vivo as administration of SECM to mice decreased susceptibility to infection by GAS. Toll-like receptor 2 (TLR2) was important to this process as a TLR2-neutralizing antibody blocked induction of hBDs 2 and 3, and Tlr2-deficient mice did not show induction of mBD4. Taken together, these findings reveal a potential use for normal commensal bacterium S. epidermidis to activate TLR2 signaling and induce antimicrobial peptide expression, thus enabling the skin to mount an enhanced response to pathogens.
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Affiliation(s)
- Yuping Lai
- Division of Dermatology, Department of Medicine, University of California, San Diego and VA San Diego Healthcare System, San Diego, California 92161, USA
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113
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Severity of Staphylococcus aureus infection of the skin is associated with inducibility of human beta-defensin 3 but not human beta-defensin 2. Infect Immun 2010; 78:3112-7. [PMID: 20404083 DOI: 10.1128/iai.00078-10] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-positive bacteria are the predominant cause of skin infections. Antimicrobial peptides (AMPs) are believed to be of major importance in skin's innate defense against these pathogens. This study aimed at providing clinical evidence for the contribution of AMP inducibility to determining the severity of Gram-positive skin infection. Using real-time PCR, we determined the induction of human beta-defensin 2 (HBD-2), HBD-3, and RNase 7 by comparing healthy and lesional mRNA levels in 32 patients with Gram-positive skin infection. We then examined whether AMP induction differed by disease severity, as measured by number of recurrences and need for surgical drainage in patients with Staphylococcus aureus-positive lesions. We found that HBD-2 and -3, but not RNase 7, mRNA expression was highly induced by Gram-positive bacterial infection in otherwise healthy skin. Less induction of HBD-3, but not HBD-2, was associated with more-severe S. aureus skin infection: HBD-3 mRNA levels were 11.4 times lower in patients with more than 6 recurrences (P = 0.01) and 8.8 times lower in patients reporting surgical drainage (P = 0.01) than in the respective baseline groups. This suggests that inducibility of HBD-3 influences the severity of Gram-positive skin infection in vivo. The physiological function of HBD-2 induction in this context remains unclear.
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114
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The effect of calcipotriol on the expression of human beta defensin-2 and LL-37 in cultured human keratinocytes. Clin Dev Immunol 2010; 2009:645898. [PMID: 20182640 PMCID: PMC2825796 DOI: 10.1155/2009/645898] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Accepted: 12/05/2009] [Indexed: 01/01/2023]
Abstract
BACKGROUND Vitamin D has been reported to regulate innate immunity by controlling the expression of antimicrobial peptides (AMPs). OBJECTIVE We investigated the effect of calcipotriol on the expression of AMPs in human cultured keratinocytes. METHODS Keratinocytes were treated with lipopolysaccharide (LPS), TNF-alpha, Calcipotriol and irradiated with UVB, cultured, and harvested. To assess the expression of human beta defensin-2 and LL-37 in the control group, not exposed to any stimulants, the experimental group was treated with LPS, TNF-alpha, or UVB, and another group was treated again with calcipotriol; reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemical staining were performed. RESULTS In the experimental group treated with LPS, UVB irradiation, and TNF-alpha, the expression of beta-defensin and LL-37 was increased more than in the control group and then decreased in the experimental group treated with calcipotriol. CONCLUSIONS Calcipotriol suppressed HBD-2 and LL-37, which were stimulated by UVB, LPS, and TNF-alpha.
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115
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Tokura Y. Extrinsic and intrinsic types of atopic dermatitis. J Dermatol Sci 2010; 58:1-7. [PMID: 20207111 DOI: 10.1016/j.jdermsci.2010.02.008] [Citation(s) in RCA: 221] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 10/19/2022]
Abstract
Atopic dermatitis (AD) can be categorized into the extrinsic and intrinsic types. Extrinsic or allergic AD shows high total serum IgE levels and the presence of specific IgE for environmental and food allergens, whereas intrinsic or non-allergic AD exhibits normal total IgE values and the absence of specific IgE. While extrinsic AD is the classical type with high prevalence, the incidence of intrinsic AD is approximately 20% with female predominance. The clinical features of intrinsic AD include relative late onset, milder severity, and Dennie-Morgan folds, but no ichthyosis vulgris or palmar hyperlinearity. The skin barrier is perturbed in the extrinsic, but not intrinsic type. Filaggrin gene mutations are not a feature of intrinsic AD. The intrinsic type is immunologically characterized by the lower expression of interleukin (IL) -4, IL-5, and IL-13, and the higher expression of interferon-gamma. It is suggested that intrinsic AD patients are not sensitized with protein allergens, which induce Th2 responses, but with other antigens, and metals might be one of the candidates of such antigens.
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Affiliation(s)
- Yoshiki Tokura
- Department of Dermatology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
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116
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Kamsteeg M, Jansen P, Van Vlijmen-Willems I, Van Erp P, Rodijk-Olthuis D, Van Der Valk P, Feuth T, Zeeuwen P, Schalkwijk J. Molecular diagnostics of psoriasis, atopic dermatitis, allergic contact dermatitis and irritant contact dermatitis. Br J Dermatol 2009; 162:568-78. [DOI: 10.1111/j.1365-2133.2009.09547.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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117
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Joly S, Compton LM, Pujol C, Kurago ZB, Guthmiller JM. Loss of human β-defensin 1, 2, and 3 expression in oral squamous cell carcinoma. ACTA ACUST UNITED AC 2009; 24:353-60. [DOI: 10.1111/j.1399-302x.2009.00512.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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118
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van Damme CM, Willemse T, van Dijk A, Haagsman HP, Veldhuizen EJ. Altered cutaneous expression of β-defensins in dogs with atopic dermatitis. Mol Immunol 2009; 46:2449-55. [DOI: 10.1016/j.molimm.2009.05.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 05/15/2009] [Accepted: 05/21/2009] [Indexed: 11/30/2022]
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119
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Bcl-3 acts as an innate immune modulator by controlling antimicrobial responses in keratinocytes. J Invest Dermatol 2009; 129:2148-55. [PMID: 19282837 DOI: 10.1038/jid.2009.49] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Innate immune responses involve the production of antimicrobial peptides (AMPs), chemokines, and cytokines. We report here the identification of B-cell leukemia (Bcl)-3 as a modulator of innate immune signaling in keratinocytes. In this study, it is shown that Bcl-3 is inducible by the Th2 cytokines IL-4 and IL-13 and is overexpressed in lesional skin of atopic dermatitis (AD) patients. Bcl-3 was shown to be important to cutaneous innate immune responses as silencing of Bcl-3 by small-interfering RNA (siRNA) reversed the downregulatory effect of IL-4 on the HBD3 expression. Bcl-3 silencing enhanced vitamin D3 (1,25D3)-induced gene expression of cathelicidin AMP in keratinocytes, suggesting a negative regulatory function on cathelicidin transcription. Furthermore, 1,25D3 suppressed Bcl-3 expression in vitro and in vivo. This study identified Bcl-3 as an important modulator of cutaneous innate immune responses and its possible therapeutic role in AD.
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120
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Jansen PAM, Rodijk-Olthuis D, Hollox EJ, Kamsteeg M, Tjabringa GS, de Jongh GJ, van Vlijmen-Willems IMJJ, Bergboer JGM, van Rossum MM, de Jong EMGJ, den Heijer M, Evers AWM, Bergers M, Armour JAL, Zeeuwen PLJM, Schalkwijk J. Beta-defensin-2 protein is a serum biomarker for disease activity in psoriasis and reaches biologically relevant concentrations in lesional skin. PLoS One 2009; 4:e4725. [PMID: 19266104 PMCID: PMC2649503 DOI: 10.1371/journal.pone.0004725] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 02/08/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Previous studies have extensively documented antimicrobial and chemotactic activities of beta-defensins. Human beta-defensin-2 (hBD-2) is strongly expressed in lesional psoriatic epidermis, and recently we have shown that high beta-defensin genomic copy number is associated with psoriasis susceptibility. It is not known, however, if biologically and pathophysiologically relevant concentrations of hBD-2 protein are present in vivo, which could support an antimicrobial and proinflammatory role of beta-defensins in lesional psoriatic epidermis. METHODOLOGY/PRINCIPAL FINDINGS We found that systemic levels of hBD-2 showed a weak but significant correlation with beta defensin copy number in healthy controls but not in psoriasis patients with active disease. In psoriasis patients but not in atopic dermatitis patients, we found high systemic hBD-2 levels that strongly correlated with disease activity as assessed by the PASI score. Our findings suggest that systemic levels in psoriasis are largely determined by secretion from involved skin and not by genomic copy number. Modelling of the in vivo epidermal hBD-2 concentration based on the secretion rate in a reconstructed skin model for psoriatic epidermis provides evidence that epidermal hBD-2 levels in vivo are probably well above the concentrations required for in vitro antimicrobial and chemokine-like effects. CONCLUSIONS/SIGNIFICANCE Serum hBD-2 appears to be a useful surrogate marker for disease activity in psoriasis. The discrepancy between hBD-2 levels in psoriasis and atopic dermatitis could explain the well known differences in infection rate between these two diseases.
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Affiliation(s)
- Patrick A. M. Jansen
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Diana Rodijk-Olthuis
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Edward J. Hollox
- Department of Genetics, University of Leicester, Leicester, United Kingdom
| | - Marijke Kamsteeg
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Geuranne S. Tjabringa
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Gys J. de Jongh
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Ivonne M. J. J. van Vlijmen-Willems
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Judith G. M. Bergboer
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Michelle M. van Rossum
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Elke M. G. J. de Jong
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Martin den Heijer
- Department of Endocrinology and Department of Epidemiology and Biostatistics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Andrea W. M. Evers
- Department of Medical Psychology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Mieke Bergers
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - John A. L. Armour
- Institute of Genetics, University of Nottingham, Nottingham, United Kingdom
| | - Patrick L. J. M. Zeeuwen
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joost Schalkwijk
- Department of Dermatology and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail:
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The Antimicrobial Protein Psoriasin (S100A7) Is Upregulated in Atopic Dermatitis and after Experimental Skin Barrier Disruption. J Invest Dermatol 2009; 129:641-9. [DOI: 10.1038/jid.2008.268] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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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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125
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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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126
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Abstract
The innate immune system evolved more than 2 billion years ago to first recognize pathogens then eradicate them. Several distinct defects in this ancient but rapidly responsive element of human immune defense account for the increased incidence of skin infections in atopics. These defects include abnormalities in the physical barrier of the epidermis, alterations in microbial pattern recognition receptors such as toll receptors and nucleotide binding oligomerization domains, and a diminished capacity to increase the expression of antimicrobial peptides during inflammation. Several antimicrobial peptides are affected including; cathelicidin, HBD-2, and HBD-3, which are lower in lesional skin of atopics compared with other inflammatory skin diseases, and dermcidin, which is decreased in sweat. Other defects in the immune defense barrier of atopics include a relative deficiency in plasmacytoid dendritic cells. In the future, understanding the cause of these defects may allow therapeutic intervention to reduce the incidence of infection in atopic individuals and potentially decrease the severity of this disorder.
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127
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Eyerich K, Pennino D, Scarponi C, Foerster S, Nasorri F, Behrendt H, Ring J, Traidl-Hoffmann C, Albanesi C, Cavani A. IL-17 in atopic eczema: linking allergen-specific adaptive and microbial-triggered innate immune response. J Allergy Clin Immunol 2008; 123:59-66.e4. [PMID: 19056110 DOI: 10.1016/j.jaci.2008.10.031] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 10/16/2008] [Accepted: 10/20/2008] [Indexed: 11/27/2022]
Abstract
BACKGROUND Patients with atopic eczema (AE) regularly experience colonization with Staphylococcus aureus that is directly correlated with the severity of eczema. Recent studies show that an impaired IL-17 immune response results in diseases associated with chronic skin infections. OBJECTIVE We sought to elucidate the effect of IL-17 on antimicrobial immune responses in AE skin. METHODS T cells infiltrating atopy patch test (APT) reactions were characterized for IL-17 secretion to varying stimuli. IL-17-dependent induction of the antimicrobial peptide human beta-defensin 2 (HBD-2) in keratinocytes was investigated. RESULTS Approximately 10% of APT-infiltrating T cells secreted IL-17 after phorbol 12-myristate 13-acetate (PMA)/ionomycin stimulation. Among these, 33% belonged to the newly characterized subtype T(H)2/IL-17. Despite the capacity to secrete IL-17, specific T-cell clones released only low amounts of IL-17 on cognate allergen stimulation, whereas IL-4, IFN-gamma, or both were efficiently induced. IL-17 secretion was not enhanced by IL-23, IL-1 beta, or IL-6 but was enhanced by the S aureus-derived superantigen staphylococcal enterotoxin B. Both healthy and AE keratinocytes upregulated HBD-2 in response to IL-17, but coexpressed IL-4/IL-13 partially inhibited this effect. In vivo, additional application of staphylococcal enterotoxin B induced IL-17 in APT reactions, whereas IL-4, IFN-gamma, and IL-10 were marginally regulated. Induced IL-17 upregulated HBD-2 in human keratinocytes in vivo. CONCLUSION IL-17-capable T cells, in particular T(H)2/IL-17 cells, infiltrate acute AE reactions. Although IL-17 secretion by specific T cells is tightly regulated, it can be triggered by bacteria-derived superantigens. The ineffective IL-17-dependent upregulation of HBD-2 in patients with AE is due to a partial inhibition by the type 2 microenvironment, which could partially explain why patients with AE do not clear S aureus.
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128
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Guttman-Yassky E, Lowes MA, Fuentes-Duculan J, Zaba LC, Cardinale I, Nograles KE, Khatcherian A, Novitskaya I, Carucci JA, Bergman R, Krueger JG. Low expression of the IL-23/Th17 pathway in atopic dermatitis compared to psoriasis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2008; 181:7420-7. [PMID: 18981165 PMCID: PMC3470474 DOI: 10.4049/jimmunol.181.10.7420] [Citation(s) in RCA: 268] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The classical Th1/Th2 paradigm previously defining atopic dermatitis (AD) and psoriasis has recently been challenged with the discovery of Th17 T cells that synthesize IL-17 and IL-22. Although it is becoming evident that many Th1 diseases including psoriasis have a strong IL-17 signal, the importance of Th17 T cells in AD is still unclear. We examined and compared skin biopsies from AD and psoriasis patients by gene microarray, RT-PCR, immunohistochemistry, and immunofluorescence. We found a reduced genomic expression of IL-23, IL-17, and IFN-gamma in AD compared with psoriasis. To define the effects of IL-17 and IL-22 on keratinocytes, we performed gene array studies with cytokine-treated keratinocytes. We found lipocalin 2 and numerous other innate defense genes to be selectively induced in keratinocytes by IL-17. IFN-gamma had no effect on antimicrobial gene-expression in keratinocytes. In AD skin lesions, protein and mRNA expression of lipocalin 2 and other innate defense genes (hBD2, elafin, LL37) were reduced compared with psoriasis. Although AD has been framed by the Th1/Th2 paradigm as a Th2 polar disease, we present evidence that the IL-23/Th17 axis is largely absent, perhaps accounting for recurrent skin infections in this disease.
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Affiliation(s)
- Emma Guttman-Yassky
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY 10021
| | - Michelle A. Lowes
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY 10021
| | | | | | - Irma Cardinale
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY 10021
| | - Kristine E. Nograles
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY 10021
| | - Artemis Khatcherian
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY 10021
| | - Inna Novitskaya
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY 10021
| | - John A. Carucci
- The Section of Mohs Micrographic and Dermatologic Surgery, Weill-Cornell Medical College of Cornell, New York
| | - Reuven Bergman
- Department of Dermatology, Rambam Medical Center and the Technion, Haifa, Israel
| | - James G. Krueger
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY 10021
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129
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Nguyen V, Huggins RH, Lertsburapa T, Bauer K, Rademaker A, Gerami P, Guitart J. Cutaneous T-cell lymphoma and Staphylococcus aureus colonization. J Am Acad Dermatol 2008; 59:949-52. [PMID: 18835065 DOI: 10.1016/j.jaad.2008.08.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 08/14/2008] [Accepted: 08/15/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND Bacterial infections are a common complication of cutaneous T-cell lymphoma (CTCL). The most common pathogen of cutaneous infections in CTCL patients is Staphylococcus aureus. OBJECTIVE The purpose of this study was to assess S aureus colonization rates among CTCL subjects compared to control subjects. METHODS Fifty subjects with CTCL, 25 psoriasis control subjects, and 25 healthy control subjects were included in this study. Culture swabs were obtained from nares and lesional skin or normal skin in the healthy controls. RESULTS S aureus colonization rates were 44% in CTCL subjects, 48% in psoriasis subjects, and 28% in healthy control subjects (P = .29). LIMITATIONS The sample size was small, and the exclusion criteria resulted in an underestimation of the colonization rate. CONCLUSION There was a trend for higher methicillin-sensitive S aureus colonization in the CTCL group compared with healthy control subjects. S aureus colonization may be directly related to body surface area of CTCL.
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Affiliation(s)
- Victoria Nguyen
- Department of Dermatology, Northwestern University, Chicago, Illinois 60611, USA
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130
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Abstract
A subgroup of patients with atopic dermatitis develops one or more episodes of a severe viral skin infection caused by herpes simplex virus superimposed on eczematous skin lesions. This condition is named atopic dermatitis complicated by eczema herpeticum. Characteristic features of patients developing eczema herpeticum include an early age of onset of atopic dermatitis with a persistent and severe course into adulthood, predilection for eczematous skin lesions in the head and neck area, elevated total serum IgE levels and increased allergen sensitisation. Deficiencies at the level of both the innate and the adaptive immune system, which have been identified in atopic dermatitis, are much more pronounced in this subgroup. Predisposing cellular factors include a reduced number of plasmacytoid dendritic cells in the epidermis and a modified capacity of these cells to produce type I interferons after allergen challenge. In addition, lower levels of antimicrobial peptides in the skin of atopic dermatitis patients, resulting in part from a Th2-prone micromilieu, contribute to the lack of an effective defence against viral attack. In this review, we summarise the current knowledge of the molecular pathogenesis of eczema herpeticum.
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131
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Defective killing of Staphylococcus aureus in atopic dermatitis is associated with reduced mobilization of human β-defensin-3. J Allergy Clin Immunol 2008; 122:62-8. [DOI: 10.1016/j.jaci.2008.04.022] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 04/21/2008] [Accepted: 04/23/2008] [Indexed: 01/27/2023]
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132
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Zeeuwen PLJM, de Jongh GJ, Rodijk-Olthuis D, Kamsteeg M, Verhoosel RM, van Rossum MM, Hiemstra PS, Schalkwijk J. Genetically programmed differences in epidermal host defense between psoriasis and atopic dermatitis patients. PLoS One 2008; 3:e2301. [PMID: 18523683 PMCID: PMC2409155 DOI: 10.1371/journal.pone.0002301] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 04/16/2008] [Indexed: 11/19/2022] Open
Abstract
In the past decades, chronic inflammatory diseases such as psoriasis, atopic dermatitis, asthma, Crohn’s disease and celiac disease were generally regarded as immune-mediated conditions involving activated T-cells and proinflammatory cytokines produced by these cells. This paradigm has recently been challenged by the finding that mutations and polymorphisms in epithelium-expressed genes involved in physical barrier function or innate immunity, are risk factors of these conditions. We used a functional genomics approach to analyze cultured keratinocytes from patients with psoriasis or atopic dermatitis and healthy controls. First passage primary cells derived from non-lesional skin were stimulated with pro-inflammatory cytokines, and expression of a panel of 55 genes associated with epidermal differentiation and cutaneous inflammation was measured by quantitative PCR. A subset of these genes was analyzed at the protein level. Using cluster analysis and multivariate analysis of variance we identified groups of genes that were differentially expressed, and could, depending on the stimulus, provide a disease-specific gene expression signature. We found particularly large differences in expression levels of innate immunity genes between keratinocytes from psoriasis patients and atopic dermatitis patients. Our findings indicate that cell-autonomous differences exist between cultured keratinocytes of psoriasis and atopic dermatitis patients, which we interpret to be genetically determined. We hypothesize that polymorphisms of innate immunity genes both with signaling and effector functions are coadapted, each with balancing advantages and disadvantages. In the case of psoriasis, high expression levels of antimicrobial proteins genes putatively confer increased protection against microbial infection, but the biological cost could be a beneficial system gone awry, leading to overt inflammatory disease.
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Affiliation(s)
- Patrick L. J. M. Zeeuwen
- Laboratory of Skin Biology and Experimental Dermatology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail: (PZ); (JS)
| | - Gys J. de Jongh
- Laboratory of Skin Biology and Experimental Dermatology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Diana Rodijk-Olthuis
- Laboratory of Skin Biology and Experimental Dermatology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Marijke Kamsteeg
- Laboratory of Skin Biology and Experimental Dermatology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Renate M. Verhoosel
- Department of Pulmonology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Michelle M. van Rossum
- Laboratory of Skin Biology and Experimental Dermatology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Pieter S. Hiemstra
- Department of Pulmonology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Joost Schalkwijk
- Laboratory of Skin Biology and Experimental Dermatology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail: (PZ); (JS)
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133
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Abstract
The innate immune system is primarily responsible for prevention of infection of the skin by pathogens, but is also important in control of inflammation. The components of innate immunity are frequently misunderstood based on a historical bias for leukocyte-mediated immune defense. Many participating cell types are often overlooked, in particular epithelial cells that provide an early and critical step to innate immune defense. This review will discuss our epithelial barrier to infection with emphasis on how microbes subvert this system, and human diseases associated with these events.
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134
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Toll-like receptor 4 ligation enforces tolerogenic properties of oral mucosal Langerhans cells. J Allergy Clin Immunol 2008; 121:368-374.e1. [DOI: 10.1016/j.jaci.2007.09.045] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 09/04/2007] [Accepted: 09/21/2007] [Indexed: 11/23/2022]
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135
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Sehra S, Tuana FMB, Holbreich M, Mousdicas N, Kaplan MH, Travers JB. Clinical correlations of recent developments in the pathogenesis of atopic dermatitis. An Bras Dermatol 2008. [DOI: 10.1590/s0365-05962008000100009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Atopic dermatitis is a chronic inflammatory skin disease with a steadily increasing prevalence affecting 10-20 of infants and 1-3 of adults globally. It is often the first clinical manifestation of atopic disease preceding asthma and allergic rhinitis. Probably half of the children with atopic dermatitis develop some other form of atopic disease later in life. The pathogenesis involves a complex interplay of factors including genetic predisposition due to altered immune or skin barrier function, interactions with the environment such as food and allergen exposures, and infectious triggers of inflammation. In this review, we summarize the recent advances in understanding the contribution of different factors in the pathophysiology of atopic dermatitis and how insights provide new therapeutic potential for its treatment.
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Affiliation(s)
- Sarita Sehra
- Center for Pediatric Research, United States of America
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136
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Abstract
PURPOSE OF REVIEW Atopic dermatitis is a chronic inflammatory skin disease associated with significant barrier disruption, T-helper type 2 mediated skin inflammation, and an impaired innate immune response. These characteristics increase the susceptibility of atopic dermatitis patients to recurrent skin infections, some of which may have potentially fatal implications. The mechanisms resulting in this increased propensity for skin infections have been an area of active investigation. RECENT FINDINGS Antimicrobial peptides are an integral component of the innate immune response due to their broad spectrum activity against invading pathogens. Recent studies have shown that these peptides are effective at killing Staphylococcus aureus, herpes simplex virus, vaccinia virus, and the Malassezia species, pathogens associated with significant morbidity in patients with atopic dermatitis. Additionally, these peptides are deficient in the skin of atopic dermatitis patients, suggesting that the increased propensity of patients towards skin infection is due to the lack of antimicrobial peptide expression. SUMMARY The current review will examine recent literature on the role of antimicrobial peptides in atopic dermatitis in an effort to improve our understanding of why patients with the condition suffer from recurrent infections.
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Affiliation(s)
- Michael D Howell
- Division of Pediatric Allergy-Immunology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.
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137
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Abstract
PURPOSE OF REVIEW Atopic dermatitis is a common chronic inflammatory skin disease and there are numerous publications on this topic. This review will focus on developments in understanding the molecular basis of atopic dermatitis while considering the genetic background, skin barrier impairment, immune system deviation and microbial superinfections. RECENT FINDINGS Atopic dermatitis is a complex genetic disease in which gene-gene and gene-environment interactions play a key role. Surprisingly some genetic regions of interest were found to be overlapping with loci identified to play a role in another very common inflammatory skin disease, psoriasis, while no overlap has so far been observed with asthma. Impairment of the skin barrier followed by antigens trespassing seems to play an important role, favouring sensitization via transepidermal penetration which is the focus of current investigations. Superinfections by pathogens such as Staphylococcus aureus due to a weak innate defence seem to be significant in atopic dermatitis as they elicit a strong inflammatory response. SUMMARY Atopic dermatitis is a chronic inflammatory skin disease with a high incidence in school children and adults. Disease pathogenesis is complex and the background is multifactorial, making the underlying predispositions elusive. Understanding new pathogenic pathways may lead to the development of new drugs with enhanced benefit for the patient.
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Affiliation(s)
- Sonja Bonness
- Department of Dermatology and Allergy, Rheinische Friedrich-Wilhelms-University Bonn, Germany
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138
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Gambichler T, Skrygan M, Tomi NS, Othlinghaus N, Brockmeyer NH, Altmeyer P, Kreuter A. Differential mRNA Expression of Antimicrobial Peptides and Proteins in Atopic Dermatitis as Compared to Psoriasis Vulgaris and Healthy Skin. Int Arch Allergy Immunol 2008; 147:17-24. [DOI: 10.1159/000128582] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Accepted: 01/08/2008] [Indexed: 11/19/2022] Open
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139
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Current World Literature. Curr Opin Allergy Clin Immunol 2007; 7:454-5. [PMID: 17873589 DOI: 10.1097/aci.0b013e3282f0cf23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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140
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Howell MD, Kim BE, Gao P, Grant AV, Boguniewicz M, Debenedetto A, Schneider L, Beck LA, Barnes KC, Leung DYM. Cytokine modulation of atopic dermatitis filaggrin skin expression. J Allergy Clin Immunol 2007; 120:150-5. [PMID: 17512043 PMCID: PMC2669594 DOI: 10.1016/j.jaci.2007.04.031] [Citation(s) in RCA: 538] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 04/11/2007] [Accepted: 04/17/2007] [Indexed: 11/29/2022]
Abstract
BACKGROUND Atopic dermatitis (AD) is a chronic inflammatory skin disease that is characterized by a defective skin barrier function. Recent studies have reported mutations of the skin barrier gene encoding filaggrin in a subset of patients with AD. OBJECTIVE We investigated whether reduced filaggrin expression was found in patients with AD who were not carriers of known filaggrin mutations and whether filaggrin expression was modulated by the atopic inflammatory response. METHODS Filaggrin expression was measured in skin biopsies and cultured keratinocytes using real-time RT-PCR and immunohistochemistry. Filaggrin loss-of-function mutations were screened in a total of 69 subjects. RESULTS Compared with normal skin, filaggrin expression was significantly reduced (P < .05) in acute AD skin, with further reduction seen in acute lesions from 3 European American subjects with AD who were heterozygous for the 2282del4 mutation. This was confirmed by using immunohistochemistry. AD skin is characterized by the overexpression of IL-4 and IL-13. Keratinocytes differentiated in the presence of IL-4 and IL-13 exhibited significantly reduced filaggrin gene expression (0.04 +/- 0.01 ng filaggrin/ng glyceraldehyde 3-phosphate dehydrogenase; P < .05) compared with media alone (0.16 +/- 0.03). CONCLUSION Patients with AD have an acquired defect in filaggrin expression that can be modulated by the atopic inflammatory response. CLINICAL IMPLICATIONS The atopic immune response contributes to the skin barrier defect in AD; therefore, neutralization of IL-4 and IL-13 could improve skin barrier integrity.
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Affiliation(s)
- Michael D Howell
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA
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141
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Reefer AJ, Satinover SM, Wilson BB, Woodfolk JA. The relevance of microbial allergens to the IgE antibody repertoire in atopic and nonatopic eczema. J Allergy Clin Immunol 2007; 120:156-63. [PMID: 17507082 DOI: 10.1016/j.jaci.2007.03.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 03/27/2007] [Accepted: 03/28/2007] [Indexed: 11/26/2022]
Abstract
BACKGROUND A propensity to microbial skin infections has been reported in atopic ("high IgE") and nonatopic ("low IgE") forms of eczema. However, the relationship between antimicrobial IgE antibodies and nonatopic disease is unclear. OBJECTIVE We examined the relevance of microbial allergens to the allergen-specific IgE antibody repertoire in patients with atopic dermatitis. METHODS Patients with IgE levels of less than 150 IU/mL were stratified according to sensitivity (n = 22) or no sensitivity (n = 27) to 11 common food allergens and aeroallergens. The prevalence and titers of antimicrobial IgE antibodies were compared with those of patients (n = 36) with increased total IgE levels (>150 IU/mL). Skin-derived serum chemokines were also analyzed. RESULTS Patients with low IgE levels showed decreased disease severity, increased age of onset, a striking female predominance, and a distinct distribution of skin lesions. High titer IgE antibodies (sum of 8 bacterial and fungal allergens = 29.8 +/- 32.6 IU/mL) and multisensitization specific for microbial allergens was characteristic of patients with high IgE levels, with an overall 84% positivity; however, antimicrobial IgE antibodies comprised 3% or less of allergen-specific IgE antibodies. By contrast, antimicrobial IgE antibodies were detected in only 20% of patients with low IgE, and titers were negligible, irrespective of sensitization to common allergens. These patients were monosensitized, and exclusive microbial sensitivity was uncommon (10%). Patients with low IgE with no sensitivity to common allergens had lower levels of serum macrophage inflammatory protein 3alpha compared with their sensitized counterparts. CONCLUSION Antimicrobial IgE antibodies are uncommon in patients with atopic dermatitis with low IgE levels. CLINICAL IMPLICATIONS Hypersensitivity to microbial allergens is an unlikely trigger for eczematous eruptions in patients with low IgE levels.
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Affiliation(s)
- Amanda J Reefer
- Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville, VA 22908-1355, USA
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142
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Howell MD, Streib JE, Leung DYM. Antiviral activity of human beta-defensin 3 against vaccinia virus. J Allergy Clin Immunol 2007; 119:1022-5. [PMID: 17353034 PMCID: PMC2668144 DOI: 10.1016/j.jaci.2007.01.044] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 01/26/2007] [Accepted: 01/29/2007] [Indexed: 10/23/2022]
Affiliation(s)
- Michael D. Howell
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA
| | - Joanne E. Streib
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA
| | - Donald YM Leung
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA
- Department of Pediatrics, University of Colorado Health Sciences Center, Denver, CO 80262 USA
- Address correspondence and reprint requests to: Donald YM Leung, MD, PhD, National Jewish Medical and Research Center, Department of Pediatrics, Room K926, 1400 Jackson Street, Denver, CO 80206, Phone: 303-398-1186; Fax: 303-270-2182;
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