Project description:Low environmental humidity aggravates symptoms of inflammatory skin diseases, e.g. of Atopic Dermatitis (AD). Using mice that develop AD-like symptoms, we show that an increase in environmental humidity rapidly rescues their cutaneous inflammation and associated epidermal abnormalities. Quantitative proteomics analysis of epidermal lysates of mice kept at low or high humidity identified novel humidity-regulated proteins, including Clca2/Clca3a2, a protein with previously unknown function in the skin.
Project description:Genome-wide analysis of gene expression in the cervical spinal cord of atopic dermatitis model mice was performed. Results provide important information for understanding of molecular mechanisms of the symptoms of atopic dermatitis.
Project description:Hedgehog (Hh) proteins are morphogens which regulate embryonic development and adult tissue homeostasis, with distinct outcomes dependent on the strength and duration of their signals. We show that the Hh signalling pathway modulates the induction and pathology of mouse atopic dermatitis. Sonic hedgehog (Shh) and Hh pathway target genes were upregulated on induction of atopic dermatitis, and the Hh pathway was activated in skin T cells, showing that they respond in vivo to Hh signals secreted from the skin. Shh upregulation reduced skin inflammation in mice, whereas pharmacological Smoothened-inhibition reduced Shh upregulation and exacerbated skin pathology. Hh-signalling to T cells prevented skin inflammation on induction of dermatitis, while inhibition of Hh-mediated transcription in T cells substantially exacerbated the disease. RNA-sequencing analysis of skin CD4+ T cells from mice with chronic atopic dermatitis revealed decreased expression of immune regulatory genes in mice with conditional inhibition of Hh-mediated transcription in T cells, and increased expression of inflammatory and chemokine genes. In contrast, constitutive Hh mediated transcription in T cells led to increased expression of immune regulatory genes in skin CD4+ T cells from mice with chronic atopic dermatitis and protected against inflammation. Hh-mediated transcription in T cells resulted in increased regulatory T (Treg) cells in the periphery and skin of dermatitis-induced mice, and increased TGF-β expression, supporting their immunoregulatory phenotype, whereas, inhibition of T cell specific Hh-mediated transcription, resulted in impaired Treg function, which permitted progression of skin inflammation.
Project description:Atopic dermatitis is increasing worldwide, correlating with air pollutions. Various organic components of pollutants activate transcription factor AhR (aryl-hydrocarbon receptor). We have established AhR-CA mice, whose keratinocytes express constitutive-active AhR, and these mice developed atopic dermatitis-like frequent scratching and allergic inflammation. In this study we performed ChIP-seq analyses and identified keratinocyte-specific AhR target genes, including inflammatory cytokines Tslp and IL33, and neurotrophic factor Artemin. While AhR-CA mice exhibited epidermal hyperinnervation and alloknesis leading to hypersensitivity to pruritus, blockade of Artemin alleviated these phenotypes. AhR-CA mice showed scratching-induced barrier insufficiency and enhanced sensitization to epicutaneously-applied antigens, recapitulating human atopic dermatitis. Consistently, AhR activation and Artemin expression was detected in the epidermis of atopic dermatitis patients and keratinocytes exposed to air pollutants. Thus, AhR in keratinocytes senses the environmental stimuli and responds to them through moderating inflammation. We propose a mechanism in which air pollution induces atopic dermatitis through AhR activation.
Project description:Atopic dermatitis (AD) is the chronic inflammatory skin disease accompanied with severe pruritus. To explore the roles of EGR1 in atopic dermatitis and the relationship between EGR1 and pruritus-scratching behavior, we used a atopic dermatitis-like mouse model driven by house dust mite (HDM) treatment in wild type and EGR1 KO mice, followed with RNA-sequencing analysis.
Project description:Atopic dermatitis is increasing worldwide, correlating with air pollutions. Various organic components of pollutants activate transcription factor AhR (aryl-hydrocarbon receptor). We have established AhR-CA mice, whose keratinocytes express constitutive-active AhR, and these mice developed atopic dermatitis-like frequent scratching and allergic inflammation. In this study we performed ChIP-seq analyses and identified keratinocyte-specific AhR target genes, including inflammatory cytokines Tslp and IL33, and neurotrophic factor Artemin. While AhR-CA mice exhibited epidermal hyperinnervation and alloknesis leading to hypersensitivity to pruritus, blockade of Artemin alleviated these phenotypes. AhR-CA mice showed scratching-induced barrier insufficiency and enhanced sensitization to epicutaneously-applied antigens, recapitulating human atopic dermatitis. Consistently, AhR activation and Artemin expression was detected in the epidermis of atopic dermatitis patients and keratinocytes exposed to air pollutants. Thus, AhR in keratinocytes senses the environmental stimuli and responds to them through moderating inflammation. We propose a mechanism in which air pollution induces atopic dermatitis through AhR activation.
Project description:A highly specific and potent small molecule antagonist of CRTH2 (chemoattractant receptor) was used to investigate the role of this Prostaglandin D2 (PGD2) receptor in chronic models of cutaneous inflammation and the underlying immune response. These RNA samples are from mice that were in a chronic (50 day) model of atopic dermatitis. Each mouse had a section of back skin patched with a gauze, and the RNA was from the patched area of skin; the control mice had the gauze soaked in PBS, whereas all the other test mice had the gauze soaked in ovalbumin dissolved in PBS. The ovalbumin acts as an allergen and induces the experimental atopic dermatitis. The six groups of mice that received the OVA patch were treated in different ways:some received just the drug vehicle during the OVA patching, others received the test drug (compound A) at 3 different concentrations: 10 mg/kg 1 mg/kg and 0.1 mg/kg. Two other cohorts received positive control drugs: ramatroban and dexamethasone .Each different sample represents a different animal.
Project description:Atopic dermatitis and psoriasis are driven by alternate type 2 and type 17 immune responses, but some proteins might be critical to both diseases. We show that a deficiency of the TNF superfamily molecule TWEAK (TNFSF12) in mice results in defective maintenance of atopic dermatitis-specific Th2 and psoriasis-specific Th17 cells in the skin, and impaired expression of disease-characteristic chemokines and cytokines, such as CCL17 and TSLP in atopic dermatitis, and CCL20 and IL-19 in psoriasis. The TWEAK receptor, Fn14, is upregulated in keratinocytes and dermal fibroblasts, and TWEAK induces these cytokines and chemokines alone and in synergy with the signature T helper cytokines of either disease, IL-13 and IL-17. Furthermore, subcutaneous injection of recombinant TWEAK into naïve mice induces cutaneous inflammation with histological and molecular signs of both diseases. TWEAK is therefore a critical contributor to skin inflammation and a possible therapeutic target in atopic dermatitis and psoriasis.