involucrin and Dermatitis--Atopic

Atopic dermatitis (AD) is an eczematous, pruritic skin disorder with extensive barrier dysfunction and elevated interleukin (IL)-4 and IL-13 signatures. The barrier dysfunction correlates with the downregulation of barrier-related molecules such as filaggrin (FLG), loricrin (LOR), and involucrin (IVL). IL-4 and IL-13 potently inhibit the expression of these molecules by activating signal transducer and activator of transcription (STAT)6 and STAT3. In addition to IL-4 and IL-13, IL-22 and IL-17A are probably involved in the barrier dysfunction by inhibiting the expression of these barrier-related molecules. In contrast, natural or medicinal ligands for aryl hydrocarbon receptor (AHR) are potent upregulators of FLG, LOR, and IVL expression. As IL-4, IL-13, IL-22, and IL-17A are all capable of inducing oxidative stress, antioxidative AHR agonists such as coal tar, glyteer, and tapinarof exert particular therapeutic efficacy for AD. These antioxidative AHR ligands are known to activate an antioxidative transcription factor, nuclear factor E2-related factor 2 (NRF2). This article focuses on the mechanisms by which FLG, LOR, and IVL expression is regulated by IL-4, IL-13, IL-22, and IL-17A. The author also summarizes how AHR and NRF2 dual activators exert their beneficial effects in the treatment of AD.

Topics: Antioxidants; Basic Helix-Loop-Helix Transcription Factors; Coal Tar; Dermatitis, Atopic; Filaggrin Proteins; Gene Expression Regulation; Humans; Interleukin-13; Interleukin-17; Interleukin-22; Interleukin-4; Interleukins; Membrane Proteins; NF-E2-Related Factor 2; Oxidative Stress; Protein Precursors; Receptors, Aryl Hydrocarbon; Resorcinols; S100 Proteins; Signal Transduction; Skin; STAT3 Transcription Factor; STAT6 Transcription Factor; Stilbenes; Tars

The prevalence of atopic dermatitis (AD), a disease characterized by severe pruritus, immune imbalance, and skin barrier dysfunction, is rapidly increasing worldwide. Deacetylasperulosidic acid (DAA) has anti-atopic activity in the three main cell types associated with AD: keratinocytes, mast cells, and eosinophils. Our study investigated the anti-atopic activity of DAA in 2,4-dinitrochlorobenzene-induced NC/Nga mice. DAA alleviated the symptoms of AD, including infiltration of inflammatory cells (mast cells and eosinophils), epidermal thickness, ear thickness, and scratching behavior. Furthermore, DAA reduced serum IgE, histamine, and IgG1/IgG2a ratio and modulated the levels of AD-related cytokines and chemokines, namely interleukin (IL)-1β, IL-4, IL-6, IL-9, IL-10, IL-12, tumor necrosis factor-α, interferon-γ, thymic stromal lymphopoietin, thymus and activation-regulated chemokine, macrophage-derived chemokine, and regulated on activation the normal T cell expressed and secreted in the serum. DAA restored immune balance by regulating gene expression and secretion of Th1-, Th2-, Th9-, Th17-, and Th22-mediated inflammatory factors in the dorsal skin and splenocytes and restored skin barrier function by increasing the expression of the pro-filaggrin gene and barrier-related proteins filaggrin, involucrin, and loricrin. These results suggest DAA as a potential therapeutic agent that can alleviate the symptoms of AD by reducing pruritus, modulating immune imbalance, and restoring skin barrier function.

Topics: Animals; Anti-Inflammatory Agents; Chemokines; Dermatitis, Atopic; Dinitrochlorobenzene; Filaggrin Proteins; Immunity; Inflammation; Keratinocytes; Male; Mast Cells; Membrane Proteins; Mice; Plant Extracts; Protein Precursors; Pruritus; Skin; T-Lymphocytes

Atopic dermatitis (AD) is one of the most common skin diseases of dogs. Defects in the skin barrier and overproduction of inflammatory cytokines may be the pathogenesis of canine AD. Therefore, the present study was aimed to quantify the gene expression of certain skin barrier proteins and inflammatory cytokines in dogs with AD. Eleven dogs with AD and three healthy dogs were included in the present study. The skin barrier proteins, namely Filaggrin (FLG) and Involucrin (IVL), gene expression was quantified by Real-time PCR in the lesional skin tissues of the atopic dogs and normal skin of the healthy dogs. In addition to the skin proteins, the gene expressions of the interleukin (IL)-13, IL-31, and tumour necrosis factor (TNF)-α were also quantified in the peripheral blood mononuclear cells (PBMCs) of these dogs. Compared to the healthy dogs, significantly higher (P ≤ 0.01) FLG gene expression and significantly (P ≤ 0.05) lower expression of the IVL gene were quantified in the skin of atopic dogs. Further, the dogs with AD revealed significantly higher expression of TNF-α (P ≤ 0.01), IL-31 (P ≤ 0.05), and IL-13 (P ≤ 0.05) as compared to the healthy dogs. The findings of our present study evidently suggest significantly increased and decreased expressions of FLG and IVL genes, respectively, which may be responsible for disruption of the skin barrier in dogs with AD. While, the over-expressions of TNF-α, IL-31, and IL-13 genes might be attributed to the clinical pathology and manifestations of AD in dogs. However, further studies are warranted to substantiate our hypothesis about pathogenesis and clinical manifestation of AD in dogs by including a large number of animals.

Topics: Animals; Cytokines; Dermatitis, Atopic; Dog Diseases; Dogs; Female; Filaggrin Proteins; Interleukin-13; Intermediate Filament Proteins; Male; Protein Precursors; Tumor Necrosis Factor-alpha

Topics: Animals; Anti-Inflammatory Agents; Cytokines; Dermatitis, Atopic; Dinitrochlorobenzene; Disease Models, Animal; Fermentation; Filaggrin Proteins; Fruit; Histamine; Immunoglobulin G; Intermediate Filament Proteins; Membrane Proteins; Mice; Morinda; Occludin; Plant Extracts; Protein Precursors; Pruritus; Skin; T-Lymphocytes, Helper-Inducer; Zonula Occludens-1 Protein

The main factors involved in the pathogenesis of atopic dermatitis (AD) are skin barrier abnormality, allergy/immunology, and pruritus. Considering how oxidative stress influences these factors, antioxidant agents may be effective candidates in the treatment of AD. To evaluate the effect of Caffeoyl-Pro-His amide (CA-PH), an antioxidant agent, on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like phenotypes in BALB/c mice. Topical sensitization and challenge by DNCB were performed on the dorsal skin of BALB/c mice to induce AD-like cutaneous lesions, phenotypes, and immunologic response. CA-PH was applied topically for 2 weeks to assess its effects on DNCB-induced AD-like phenotypes. As a result, CA-PH relieved DNCB-induced AD-like phenotypes quantified by dermatitis severity score, scratching duration, and trans-epidermal water loss. Histopathological analysis showed that CA-PH decreased epidermal thickening, the number of mast cells, and eosinophil infiltration in dermis. Immunohistochemical staining revealed that CA-PH recovered skin barrier-related proteins: filaggrin, involucrin, and loricrin. As for the immunologic aspects, CA-PH treatment lowered mRNA or protein levels of interleukin (IL)-4, IL-6, IL-17a, IL-1b, IL-31, and IL-33 levels and thymic stromal lymphopoietin (TSLP) levels in cutaneous tissue, reducing the DNCB-induced serum IgE level elevation. In conclusion, topical CA-PH may be a therapeutic option for the treatment of AD.

Topics: Amides; Animals; Antioxidants; Caffeic Acids; Cytokines; Dermatitis, Atopic; Dinitrochlorobenzene; Eosinophils; Female; Filaggrin Proteins; Heme Oxygenase-1; Immunoglobulin E; Interleukins; Intermediate Filament Proteins; Mast Cells; Membrane Proteins; Mice; Mice, Inbred BALB C; Protein Precursors; Pruritus; Skin; Thymic Stromal Lymphopoietin; Tight Junctions

Essential oil derived from Chamaecyparis obtusa (EOCO) has been used as an alternative treatment for allergy-related diseases due to its immune-modulating characteristics. Clothing has the longest and most intense contact with human skin, and functional fabrics with intrinsic properties have been increasingly implemented in medical applications. Specially designed fabrics may support atopic dermatitis (AD) treatment. In this study, the effects of fabric containing EOCO on AD were investigated using an NC/Nga mouse model.. The fabric was applied for 6 h per day for 14 days. The therapeutic effects were evaluated according to measurements of skin lesion severity (modified SCORAD score), transepidermal water loss (TEWL), serum IgE and inflammatory cytokine levels, lesion thickness measured after hematoxylin and eosin staining, and immunohistochemical and Western blot analysis for skin epidermal differentiation protein.. The EOCO group exhibited significantly reduced modified SCORAD score, TEWL, and serum IgE levels. Among the inflammatory cytokines analyzed, only the mean values of regulated on activation, normal T cell expressed and secreted were observed to be decreased compared with other control groups. The histological analysis of the skin also revealed that the EOCO group expressed reduced epidermal hyperplasia and recovered filaggrin, involucrin, and loricrin expression.. It was confirmed that fabric containing EOCO has anti-atopic and anti-inflammatory properties. The study data show that fabric containing EOCO can be implemented as an alternative functional clothing for people suffering from AD.

Topics: Animals; Anti-Inflammatory Agents; Chamaecyparis; Clothing; Cotton Fiber; Cytokines; Dermatitis, Atopic; Filaggrin Proteins; Immunoglobulin E; Intermediate Filament Proteins; Male; Membrane Proteins; Mice; Oils, Volatile; Phytotherapy; Protein Precursors; Skin

Interleukin (IL)-13 plays a key role in the pathogenesis of atopic dermatitis (AD). Our preliminary study demonstrated that forced expression of miR-143 could block IL-13-induced down-regulation of epidermal barrier related proteins in epidermal keratinocytes. As previous studies suggested that miR-143 expression was regulated by mammalian target of rapamycin (mTOR) signaling pathway, we investigated the mechanism of mTOR signaling pathway in the epidermal barrier dysfunction of AD. The HaCaT cells were stimulated by IL-13 and subsequently treated with rapamycin. The expression levels of miR-143, IL-13 receptor α1 (IL-13Rα1), p-mTOR, p-S6K1, p-Akt, and epidermal barrier related proteins were analyzed through RT-qPCR and/or western blotting. The current study showed that IL-13 increased the expression levels of p-mTOR, p-S6K1, and p-Akt, and that rapamycin blocked IL-13-induced down-regulation of miR-143, suppressed the IL-13Rα1 expression and up-regulated the expressions of filaggrin, loricrin, and involucrin in HaCaT cells. This study proposed that IL-13 could activate the mTOR signaling pathway, and confirmed the vital role of mTOR-miR-143 signaling axis in the pathogenesis of AD. It provided solid evidences regarding rapamycin as a potential effective therapeutic option in the management of AD.

Topics: Dermatitis, Atopic; Filaggrin Proteins; HaCaT Cells; Humans; Interleukin-13; Interleukin-13 Receptor alpha1 Subunit; Keratinocytes; Membrane Proteins; MicroRNAs; Protein Precursors; S100 Proteins; Signal Transduction; Sirolimus; Skin; TOR Serine-Threonine Kinases; Up-Regulation

Topics: Dermatitis, Atopic; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Humans; Interleukin-13; Interleukin-13 Receptor alpha2 Subunit; Keratinocytes; p38 Mitogen-Activated Protein Kinases; Protein Kinase Inhibitors; Protein Precursors; Signal Transduction; Skin; Up-Regulation

Filaggrin (FLG) mutation is a well-confirmed genetic aberration in atopic dermatitis (AD). Genome-wide association studies on AD have revealed other susceptibility genes, for example, Ovo-like 1 (OVOL1). Nonetheless, the relation between FLG and OVOL1 is unclear. Because aryl hydrocarbon receptor (AHR; a ligand-activated transcription factor), plays a role in FLG expression in keratinocytes, we hypothesized that AHR regulates FLG expression via OVOL1. To demonstrate this mechanism, we analyzed FLG expression in OVOL1-overexpressing or OVOL1-knockdown normal human epidermal keratinocytes (NHEKs). Furthermore, we tested whether AHR activation by 6-formylindolo(3,2-b)carbazole (FICZ), an endogenous AHR ligand, or Glyteer, clinically used soybean tar, upregulates FLG and OVOL1 expression in NHEKs. We found that (1) OVOL1 regulates FLG expression; (2) AHR activation upregulates OVOL1; and (3) AHR activation upregulates FLG via OVOL1. Moreover, nuclear translocation of OVOL1 was less pronounced in AD skin compared with normal skin. IL-4-treated NHEKs, an in vitro AD skin model, also showed inhibition of the OVOL1 nuclear translocation, which was restored by FICZ and Glyteer. Thus, targeting the AHR-OVOL1-FLG axis may provide new therapeutics for AD.

Topics: Carbazoles; Cell Culture Techniques; Cell Line; Cell Nucleus; Dermatitis, Atopic; DNA-Binding Proteins; Filaggrin Proteins; Humans; Interleukin-4; Intermediate Filament Proteins; Keratinocytes; Membrane Proteins; Protein Precursors; Receptors, Aryl Hydrocarbon; RNA Interference; RNA, Small Interfering; Tars; Transcription Factors; Transglutaminases; Up-Regulation

Atopic dermatitis (AD) is characterized by a defective skin barrier, which increases the penetration of allergens and pathogens through the skin. The role of interleukin (IL)‑17, a pro‑inflammatory cytokine, in the pathogenesis of AD remains to be elucidated. The present study aimed to examine the effects of IL‑17 on skin barrier proteins in the HaCaT cell line. The expression levels of filaggrin (FLG) and involucrin (IVL) were evaluated by reverse transcription‑quantitative polymerase chain reaction and western blot analyses of the HaCaT cells following IL‑17 simulation. The role of IL‑17 was further examined by using small molecule inhibitors of extracellular signal‑regulated kinase (ERK) and P38. Treatment of the HaCaT cells with IL‑17 resulted in reduced expression levels of FLG and IVL at the mRNA and protein levels. In addition, the gene expression levels of FLG and IVL were significantly reduced in the HaCaT cells by IL‑4. Treatment with the mitogen‑activated protein kinase (MAPK) inhibitors, SB203580 and PD98059, significantly inhibited the effects of IL‑17 on the gene and protein expression levels of FLG and IVL. Finally, the protein levels of phosphorylated ERK and P38 were significantly increased following IL‑17 stimulation. Taken together, the results revealed that IL‑17 reduced the expression of FLG and IVL in HaCaT cells, and this effect involved the P38/ERK MAPK signaling pathways.

Topics: Cell Line; Dermatitis, Atopic; Filaggrin Proteins; Humans; Interleukin-17; Intermediate Filament Proteins; MAP Kinase Signaling System; Protein Precursors; Skin

The presence of congenitally impaired skin barrier followed by atopic dermatitis (AD) is an initial step in the atopic march. The maintenance of acidic pH in the stratum corneum (SC) has been suggested as a therapeutic or preventive strategy for barrier impairment caused by skin inflammation. To determine whether an AD murine model, flaky tail mice, with inherited filaggrin deficiency could develop airway inflammation by repeated topical application followed by nasal inhalation of house dust mite (HDM) antigen (defined as a novel "atopic march animal model"), and whether maintenance of an acidic SC environment by continuous application of acidic cream could interrupt the following atopic march. During the course of HDM treatment, acidic cream (pH2.8) or neutral cream (pH7.4) was applied to flaky tail mice twice daily. Repeated applications and inhalations of HDM to flaky tail mice induced AD skin lesions followed by respiratory allergies. Maintenance of SC acidity inhibited the occurrence of respiratory allergic inflammation as well as AD-like skin lesions. Collectively, a novel atopic march model could be developed by repeated epicutaneous and nasal applications of HDM to flaky tail mice, and that the acidification of SC could prevent the atopic march from AD to respiratory allergy.

Topics: Administration, Cutaneous; Animals; Antigens, Dermatophagoides; Cytokines; Dermatitis, Atopic; Disease Models, Animal; Disease Progression; Epidermis; Female; Filaggrin Proteins; Hydrogen-Ion Concentration; Immunoglobulin E; Inhalation Exposure; Intermediate Filament Proteins; Membrane Proteins; Mice; Protein Precursors; Respiratory Hypersensitivity; Skin Cream; Thymic Stromal Lymphopoietin

Skin barrier defects play an important role in atopic dermatitis (AD). Involucrin, an important barrier protein suppressed in human AD, is downregulated by interleukin-4 (IL-4). However, the molecular mechanism for IL-4 downregulation of involucrin has not been delineated, and especially how Stat6, a transcriptional activator, represses involucrin expression is unknown. Since Stats usually recruit p300/CBP in the general transcription machinery of their target genes and involucrin expression also involves p300/CBP, we hypothesize that Stat6 activated by IL-4 may sequestrate p300/CBP from the involucrin transcription complex, thus suppressing involucrin expression in keratinocytes. Using IL-4 transgenic mice, an AD mouse model, we find that involucrin expression is similarly downregulated as in human AD. In HaCat cells, the Jak inhibitor and dominant negative studies indicate that the Jaks-Stat6 pathway is involved in IL-4 downregulation of involucrin. Next, we transfected HaCat cells with an involucrin promoter-luciferase construct and then treated them with IL-4. IL-4 greatly suppresses the promoter activity, which is totally abolished by cotransfecting the CREB-binding protein (CBP) expression vector, indicating that IL-4 cannot downregulate involucrin in the presence of excess CBP. Finally, chromatin immunoprecipitation assay demonstrates that IL-4 decreases CBP binding to the involucrin transcription complex. For the first time, we defined a molecular mechanism for IL-4 downregulation of involucrin in keratinocytes, which may play an important role in the pathogenesis of AD.

Topics: Animals; Cell Line; CREB-Binding Protein; Dermatitis, Atopic; Dermis; Disease Models, Animal; Down-Regulation; Gene Expression Regulation; Humans; Interleukin-4; Keratinocytes; Mice; Mice, Transgenic; Multiprotein Complexes; Protein Binding; Protein Precursors; STAT6 Transcription Factor; Transcription, Genetic

Atopic dermatitis is a chronic inflammatory skin disease characterized by the dysregulation of the epidermal barrier and the immune system. Interleukin (IL)-13, a key T helper 2 cytokine, has been shown to impair the epidermal barrier function via downregulating epidermal barrier proteins. MicroRNAs are small noncoding RNAs of approximately 22 nucleotides that act as negative regulators of gene expression at posttranscriptional levels. MicroRNA-143 is known to be a tumor suppressor in various tumors; however, its role in the regulation of allergic diseases including atopic dermatitis remains elusive. In this study, we investigated whether IL-13Rα1 was a microRNA-143 target to regulate the effects of IL-13 on epidermal barrier function. After the stimulation of IL-13 in human epidermal keratinocytes, the level of microRNA-143 was decreased. The luciferase activity of the vector containing 3'UTR of IL-13Rα1 was decreased in keratinocytes transfected with microRNA-143 mimic compared to those of the corresponding controls. The forced expression of microRNA-143 mimic blocked the IL-13-induced downregulation of filaggrin, loricrin, and involucrin in epidermal keratinocytes. Collectively, these data suggest that microRNA-143 suppresses IL-13 activity and inflammation through targeting of IL-13Rα1 in epidermal keratinocytes. MicroRNA-143 may serve as a potential preventive and therapeutic target in atopic dermatitis.

Topics: Cells, Cultured; Dermatitis, Atopic; Epidermis; Filaggrin Proteins; Humans; Interleukin-13; Interleukin-13 Receptor alpha1 Subunit; Intermediate Filament Proteins; Keratinocytes; Membrane Proteins; MicroRNAs; Protein Precursors

Topics: Animals; Antimicrobial Cationic Peptides; Dermatitis, Atopic; Galectins; Gene Expression Profiling; Membrane Proteins; Mice; Microbiota; Plakins; Protein Precursors; Skin

Topics: Adolescent; Adult; Aged; Basement Membrane; Child; Child, Preschool; Chronic Disease; Collagen Type IV; Dermatitis, Atopic; Eczema; Female; Filaggrin Proteins; Humans; Infant; Integrin alpha6; Interleukin-13; Intermediate Filament Proteins; Male; Membrane Proteins; Middle Aged; Protein Precursors; Skin; Tissue Culture Techniques; Young Adult

The aim of the present study was to identify key genes associated with atopic dermatitis (AD) using microarray data and bioinformatic analyses. The dataset GSE6012, downloaded from the Gene Expression Omnibus (GEO) database, contains gene expression data from 10 AD skin samples and 10 healthy skin samples. Following data preprocessing, differentially expressed genes (DEGs) were identified using the limma package of the R project. Interaction networks were constructed comprising DEGs that showed a degree of node of >3, >5 and >10, using the Osprey software. Functional enrichment and pathway enrichment analysis of the network comprising all DEGs and of the network comprising DEGs with a high degree of node, were performed with the DAVID and WebGestalt toolkits, respectively. A total of 337 DEGs were identified. The functional enrichment analysis revealed that the list of DEGs was significantly enriched for proteins related to epidermis development (P=2.95E-07), including loricrin (LOR), keratin 17 (KRT17), small proline-rich repeat proteins (SPRRs) and involucrin (IVL). The chemokine signaling pathway was the most significantly enriched pathway (P=0.0490978) in the network of all DEGs and in the network consisting of high degree‑node DEGs (>10), which comprised the genes coding for chemokine receptor 7 (CCR7), chemokine ligand (CCL19), signal transducer and activator of transcription 1 (STAT1), and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1). In conclusion, the list of AD-associated proteins identified in this study, including LOR, KRT17, SPRRs, IVL, CCR7, CCL19, PIK3R1 and STAT1 may prove useful for the development of methods to treat AD. From these proteins, PIK3R1 and KRT17 are novel and promising targets for AD therapy.

Topics: Chemokine CCL19; Class Ia Phosphatidylinositol 3-Kinase; Computational Biology; Cornified Envelope Proline-Rich Proteins; Databases, Genetic; Dermatitis, Atopic; Gene Regulatory Networks; Humans; Keratin-17; Membrane Proteins; Oligonucleotide Array Sequence Analysis; Phosphatidylinositol 3-Kinases; Protein Precursors; Receptors, CCR7; Signal Transduction; Software; STAT1 Transcription Factor

Atopic dermatitis, which is related to dermatologic disorders and is associated with skin barrier dysfunction, represents an epidemic problem demanding effective therapeutic strategies. In the present study, we showed that the treatment with Eruca sativa extract resulted in a significant increase in the transactivation activity of peroxisome proliferator-activated receptor (PPAR) response element such as PPAR-α and suppression in the expression of inflammatory cytokine and antimicrobial peptides. In addition, E. sativa extract promotes the expression of filaggrin related to skin barrier protection. Quercetin and isorhamnetin, flavonoids' constituents of E. sativa, also promoted PPAR-α activity. These results indicate that E. sativa extract may be an appropriate material for improving skin barrier function as a skin therapeutic agent for atopic dermatitis.

Topics: Anti-Inflammatory Agents; Antioxidants; Brassicaceae; Cell Line; Cells, Cultured; Cytokines; Dermatitis, Atopic; Fibroblasts; Filaggrin Proteins; Flavonoids; Humans; Intermediate Filament Proteins; Keratinocytes; Plant Extracts; PPAR alpha; Protein Precursors; Quercetin; Skin

Atopic dermatitis can result from loss of structural proteins in the outermost epidermal layers, leading to a defective epidermal barrier. To test whether this influences tumour formation, we chemically induced tumours in EPI-/- mice, which lack three barrier proteins-Envoplakin, Periplakin, and Involucrin. EPI-/- mice were highly resistant to developing benign tumours when treated with 7,12-dimethylbenz(a)anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA). The DMBA response was normal, but EPI-/- skin exhibited an exaggerated atopic response to TPA, characterised by abnormal epidermal differentiation, a complex immune infiltrate and elevated serum thymic stromal lymphopoietin (TSLP). The exacerbated TPA response could be normalised by blocking TSLP or the immunoreceptor NKG2D but not CD4+ T cells. We conclude that atopy is protective against skin cancer in our experimental model and that the mechanism involves keratinocytes communicating with cells of the immune system via signalling elements that normally protect against environmental assaults.DOI: http://dx.doi.org/10.7554/eLife.01888.001.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Carcinoma, Squamous Cell; Cell Communication; Cell Differentiation; Cell Transformation, Neoplastic; Cytokines; Dermatitis, Atopic; Disease Models, Animal; Epidermis; Keratinocytes; Membrane Proteins; Mice, 129 Strain; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Mice, Nude; NK Cell Lectin-Like Receptor Subfamily K; Papilloma; Permeability; Plakins; Protein Precursors; Signal Transduction; Skin Neoplasms; Tetradecanoylphorbol Acetate; Thymic Stromal Lymphopoietin; Time Factors

Equine insect bite hypersensitivity (IBH) is a seasonal IgE-mediated dermatosis caused by bites of insects of the genus Culicoides. A familial predisposition for the disease has been shown but, except for the MHC, the genes involved have not been identified so far. An immunogenomic analysis of IBH was performed in a model population of Old Kladruby horses, all living in the same environment. Clinical signs of IBH were used as phenotypic manifestation of IBH. Furthermore, total serum IgE levels were determined in the sera of these horses and used as an independent phenotypic marker for the immunogenetic analysis. Single nucleotide polymorphisms (SNPs) in candidate immunity-related genes were used for association analyses. Genotypes composed of two to five genes encoding interferon gamma -IFNG, transforming growth factor beta 1 -TGFB1, Janus kinase 2 -JAK2, thymic stromal lymphopoietin -TSLP, and involucrin -IVL were associated with IBH, indicating a role of the genes in the pathogenesis of IBH. These findings were supported by analysis of gene expression in skin biopsies of 15 affected and 15 unaffected horses. Two markers associated with IBH, IFNG and TGFB1, showed differences in mRNA expression in skin biopsies from IBH-affected and non-affected horses (p<0.05). Expression of the gene coding for the CD14 receptor molecule -CD14 was different in skin biopsies at p<0.06. When total IgE levels were treated as binary traits, genotypes of IGHE, ELA-DRA, and IL10/b were associated with this trait. When treated as a continuous trait, total IgE levels were associated with genes IGHE, FCER1A, IL4, IL4R, IL10, IL1RA, and JAK2. This first report on non-MHC genes associated with IBH in horses is thus supported by differences in expression of genes known to play a role in allergy and immunity.

Topics: Allergens; Animals; Ceratopogonidae; Cytokines; Dermatitis, Atopic; Female; Gene Expression; Horse Diseases; Horses; Immunoglobulin E; Insect Bites and Stings; Interferon-gamma; Janus Kinase 2; Major Histocompatibility Complex; Polymorphism, Single Nucleotide; Protein Precursors; RNA, Messenger; Salivary Proteins and Peptides; Thymic Stromal Lymphopoietin; Transforming Growth Factor beta1

The mechanism of action of pimecrolimus (PIM) on atopic lesions is still under consideration. Thus far, we have evidence of its anti-inflammatory and immunomodulatory activity, and recent papers focus on its effect on epidermal barrier function. This study analysed changes in the expression of genes associated with skin barrier dysfunction in atopic dermatitis (AD) skin lesions after 2 weeks of exposure to PIM 1% cream. A real-time quantitative PCR analysis of selected epidermal differentiation complex genes and three alternative pathway keratins was performed in skin biopsies from 11 individuals with AD before and after PIM exposure. The real-time quantitative PCR analysis was compared to non-lesional skin in the same patients. Involucrin, a small proline-rich region (SPRR) 2C gene, and alternative pathway keratin 16 showed significant over-expression in lesional skin followed by significant decrease after PIM therapy. The SPRR1A gene, S100A9, and keratin 6A were also increased; however, the decrease after PIM treatment was not significant. The changes in S100 A2, A7 and A8 followed a similar course with borderline significance. SPRR4 had a significant decrease in expression in lesional versus non-lesional skin, which persisted after PIM treatment. No significant changes were detected in mRNA expression levels of filaggrin and loricrin. Our results suggest that PIM can be effective in restoring the epidermal barrier in patients with AD at least in part by its impact on expression of genes, which are important for the normal barrier function of skin.

Topics: Adult; Cornified Envelope Proline-Rich Proteins; Dermatitis, Atopic; Dermatologic Agents; Female; Filaggrin Proteins; Gene Expression; Gene Expression Profiling; Humans; Keratin-16; Keratin-6; Male; Middle Aged; Ointments; Protein Precursors; RNA, Messenger; Skin; Tacrolimus; Treatment Outcome; Young Adult

Canine atopic dermatitis (CAD) is a common allergic skin disease in dogs, associated with a defective epidermal barrier. In this study we investigated the alterations in skin keratinocyte proliferation and differentiation in CAD by quantitative reverse transcription-polymerase chain reaction. Gene expression of keratin (KRT) markers of proliferative and differentiated keratinocytes, together with that of cornified envelope proteins, involucrin (IVL) and filaggrin (FLG), were evaluated. An upregulation of KRT5 and KRT17 in both lesional and non-lesional AD skin was observed (p<0.05) whereas KRT2e, KRT14, IVL and FLG expression were significantly increased only in lesional AD skin (p<0.05). Additionally, the expression levels of KRT5, KRT14, KRT17 and IVL in CAD were strongly correlated. In conclusion, the expression of the majority of the studied keratins, as well as IVL and FLG is increased in CAD with close correlation between the proliferative keratins. This is the first report of a correlation of KRT and IVL genes with CAD.

Topics: Animals; Dermatitis, Atopic; Dog Diseases; Dogs; Filaggrin Proteins; Gene Expression Regulation; Intermediate Filament Proteins; Keratins; Protein Precursors; Skin; Transcriptome

Discovery of the significant impact of filaggrin (FLG) mutations on the genetic predisposition to atopic dermatitis (AD) focused attention on the 1q21 locus, where not only FLG but also other epidermal genes are located. In the present study, we compared 1q21 gene expression in lesional versus nonlesional AD skin.. A real-time quantitative PCR analysis of 10 1q21 genes, selected on the basis of a previous microarray study, was performed in skin biopsies from 33 individuals with AD. Three alternative pathway keratins were also evaluated.. In chronic AD skin lesions, we observed an increase in RNA encoding involucrin, S100 calcium-binding proteins A2 and A7-A9 and small proline-rich region (SPRR) proteins 1A and 2C, with fold changes ranging from 2.0 for S100A2 to 15.4 for S100A8 (p < 0.001, Bonferroni corrected), in parallel to the overexpression of the alternative pathway keratins 6A, 6B and 16. The loricrin (LOR) expression level was significantly decreased in lesional AD skin (fold change 0.5; p < 0.01). The expression of the majority of 1q21 genes and alternative keratins was closely correlated; however, for SPRR1A (and SPRR2C) in lesional skin, the correlation with other genes was lost.. We hypothesize that the deregulated increase in SPRR1A expression in chronic atopic skin lesions reflects an insufficient rise in SPRR transcripts, unable to compensate for the lack of LOR and thus contributing to the persistence of chronic AD skin lesions. Turning off the stress response in the skin may be regarded as a goal in the treatment of AD skin lesions, and SPRR genes might be targets for such an approach.

Topics: Adult; Chronic Disease; Cornified Envelope Proline-Rich Proteins; Dermatitis, Atopic; Female; Filaggrin Proteins; Gene Expression Regulation; Humans; Immunoglobulin E; Intermediate Filament Proteins; Keratins; Male; Membrane Proteins; Middle Aged; Protein Precursors; S100 Proteins; Skin

Atopic dermatitis (AD) is characterized by a defective skin barrier which allows increased allergen and pathogen penetration. Loricrin (LOR) and involucrin (IVL) are proteins important for skin barrier formation and integrity. In this study, we demonstrate that the gene and protein expression of LOR and IVL is significantly decreased in involved (LOR: p<0.001; IVL: p<0.001) and uninvolved (LOR: p<0.001; IVL: p<0.001) skin of AD subjects, as compared to skin from healthy subjects. Using primary keratinocytes, we further demonstrate the down-regulatory effect of IL-4 and IL-13--which are over-expressed in the skin of AD patients--on LOR and IVL expression in keratinocytes. Additionally, skin biopsies from signal transducer and activator of transcription (STAT)-6 transgenic mice were deficient in the expression and production of LOR and IVL. This study suggests that Th2 cytokines inhibit expression of LOR and IVL through a STAT-6 dependent mechanism.

Topics: Adult; Animals; Cytokines; Dermatitis, Atopic; Down-Regulation; Humans; Keratinocytes; Membrane Proteins; Mice; Mice, Transgenic; Protein Precursors; STAT6 Transcription Factor; Th2 Cells

The cornified envelope is assembled from transglutaminase cross-linked proteins and lipids in the outermost epidermal layers and is essential for skin barrier function. Involucrin, envoplakin, and periplakin form the protein scaffold on which the envelope assembles. To examine their combined function, we generated mice deficient in all three genes. The triple knockouts have delayed embryonic barrier formation and postnatal hyperkeratosis (abnormal accumulation of cornified cells) resulting from impaired desquamation. Cornified envelopes form but are ultrastructurally abnormal, with reduced lipid content and decreased mechanical integrity. Expression of proteases is reduced and the protease inhibitor, serpina1b, is highly upregulated, resulting in defective filaggrin processing and delayed degradation of desmoglein 1 and corneodesmosin. There is infiltration of CD4+ T cells and a reduction in resident gammadelta+ T cells, reminiscent of atopic dermatitis. Thus, combined loss of the cornified envelope proteins not only impairs the epidermal barrier, but also changes the composition of T cell subpopulations in the skin.

Topics: Animals; Animals, Newborn; CD4-Positive T-Lymphocytes; Cell Adhesion; Chemotaxis, Leukocyte; Dermatitis, Atopic; Epidermis; Epithelial Cells; Filaggrin Proteins; Intermediate Filament Proteins; Membrane Proteins; Mice; Mice, Knockout; Microscopy, Electron, Transmission; Peptide Hydrolases; Plakins; Protease Inhibitors; Protein Precursors

A defective permeability barrier leads to the penetration of environmental allergens into the skin and initiates immunological reactions and inflammation crucially involved in the pathogenesis of atopic dermatitis (AD). Decreased stratum corneum ceramide content may cause the defect in permeability barrier function consistently found in AD. Acid and neutral sphingomyelinase (A- and N-SMase) generate ceramides with structural and signal transduction functions in epidermal proliferation and differentiation. We determined epidermal SMase activities, DNA synthesis, involucrin, loricrin, filaggrin, and keratin expression in lesional and non-lesional skin of AD patients. We found decreased epidermal A-SMase activity in lesional and non-lesional skin, correlating with reduced stratum corneum ceramide content and disturbed barrier function. N-SMase activity was reduced in non-lesional skin and more significantly reduced in lesional skin, correlating with impaired expression of cornified envelope proteins and keratins, important for skin barrier function. Changes in involucrin, loricrin, filaggrin, keratin K 5 (basal) and K 16 (proliferation associated) were noticed in non-lesional and lesional skin, whereas changes in K 10 (suprabasal), K 6 (proliferation associated), and K 17 (inflammation associated) were found only in lesional skin. In summary, reduction in SMase-generating ceramides and impaired differentiation are involved in the defective barrier function found in AD.

Topics: Biomarkers; Blotting, Western; Cell Differentiation; Cell Division; Ceramides; Dermatitis, Atopic; Epidermis; Female; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Keratins; Male; Membrane Proteins; Protein Precursors; Signal Transduction; Sphingomyelin Phosphodiesterase; Substrate Specificity; Water

The amounts of the epidermal proteins filaggrin, involucrin, cystatin A and Ted-H-1 antigen produced during the terminal differentiation of keratinocytes were immunohistochemically measured in lesional and nonlesional skin of atopic dermatitis (AD) patients. In addition, the amount of filaggrin in the skin of the inner surface of the upper arm of AD patients (nonlesional skin) and normal controls, obtained by punch biopsy, was measured by an enzyme-linked immunosorbent assay (ELISA) technique. The immunohistochemical study showed that all four proteins were decreased in lesional skin. By contrast, only filaggrin was decreased in nonlesional skin of AD patients. The ELISA showed that the amount of filaggrin in the skin of the inner surface of the upper arm was 2.48 +/- 0.45 microgram/7 mm2 (n = 8) in AD patients, which was 32% of that in the normal controls (7.7 +/- 0.55 microgram/7 mm2; n = 4). This decrease in filaggrin production in atopic skin may be one of the reasons why atopic skin can easily become dry, because filaggrin is thought to be the precursor protein of the emollient factors in the stratum corneum. The evidence that only the expression of filaggrin was suppressed in AD patients, though the genes of filaggrin and involucrin are localized to a very restricted portion of the same gene 1q21, indicates that the filaggrin gene does not share regulatory elements with the involucrin gene.

Topics: Adolescent; Adult; Antigens; Cell Differentiation; Cystatins; Dermatitis, Atopic; Epidermis; Female; Filaggrin Proteins; Humans; Immunoblotting; Immunohistochemistry; Intermediate Filament Proteins; Keratinocytes; Linear Models; Male; Protein Precursors