Project description:In this study we used genomic profiling to characterize differences in expression of genes related to epidermal growth/differentiation and inflammatory circuits in skin lesions of psoriasis and atopic dermatitis (AD), comparing expression values to normal skin. Skin biopsies were collected from 9 patients with chronic atopic dermatitis, 15 psoriasis patients, and 9 healthy volunteers. Keywords: Genetic-pathology
Project description:In this study we used genomic profiling to characterize differences in expression of genes related to epidermal growth/differentiation and inflammatory circuits in skin lesions of psoriasis and atopic dermatitis (AD), comparing expression values to normal skin. Skin biopsies were collected from 9 patients with chronic atopic dermatitis, 15 psoriasis patients, and 9 healthy volunteers. Keywords: Genetic-pathology Psoriasis and AD are common inflammatory skin diseases which share important features, including: 1) large infiltrates of T-cells and inflammatory dendritic cells in skin lesions, 2) immune activation with up-regulated expression of many cytokines, chemokines, and inflammatory molecules 3) marked epidermal hyperplasia in chronic diseased skin and 4) defective barrier function with increased transepidermal water loss (TEWL), which reflects underlying alterations in keratinocyte differentiation. Using genomic profiling we provide a comprehensive comparison of chronic psoriasis and AD skin lesions as compared with normal skin.
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:Epidermal keratinocytes are key for maintenance of the integrity of the epidermis. One of the main drivers of keratinocyte differentiation is the calcium gradient; calcium concentration gradually increases towards the outer layers of the epidermis. Atopic dermatitis (AD) is a disorder associated with a chronic inflammatory state and a compromised epidermal barrier. Keratinocytes secrete lipid-rich small extracellular vesicles (sEVs) that acts as mediators of both local and long-distance signaling.
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: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 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, which is a common inflammatory skin disease characterized by persistent epidermal barrier dysfunction, is a systemic health burden reducing overall quality of life of the person. Recently, we showed that the nonstructural extracellular matrix molecule Thrombospondin-4 (THBS4) was upregulated in psoriatic skin lesions by more than 2-fold. In addition, THBS4 contributed to both skin regeneration and wound healing in vitro and in vivo. In the present work we found that THBS4 is also abundantly expressed in atopic dermatitis (AD) patient skin biopsies. By using a proteotransciptomic approach we show that stimulation of primary keratinocytes with THBS4 activates multiple factors, including inflammation, migration, proliferation, keratinocyte differentiation, by which THBS4 could participate in AD progression and contribute to the wound healing process.
Project description:Recently, it was shown that lesional skin of atopic dermatitis patients expresses low levels of some antimicrobial peptides, compared with psoriasis patients. Here we performed microarray analysis on mRNA from purified lesional epidermal cells of patients with chronic plaque psoriasis and chronic atopic dermatitis, to investigate whether this is a general phenomenon for host defense proteins, and how specific it is for this class of molecules. We found overexpression of many antimicrobial genes in keratinocytes from psoriatic skin compared with atopic dermatitis skin. Interestingly, we observed that markers of normal differentiation and the activated/hyperproliferative epidermal phenotype were expressed at equal levels. Chronic lesions of psoriasis and atopic dermatitis patients are remarkably similar with respect to cellular proliferation. We conclude that psoriatic epidermis expresses high levels of host defense proteins compared with atopic dermatitis epidermis, and this phenomenon appears to be specific for these proteins. It remains to be investigated whether this is caused by genetic polymorphisms in pathways leading to an epidermal antimicrobial response, or by differences in the cellular infiltrate in psoriasis compared with atopic dermatitis. In general the microarray technique is used to probe a (very large) number of genes for say the deseased and the healthy state.Then gene ontology is used to detect the involved pathways.We did not set out to find a comprehensive list of genes involved in these skin deseases.We do suspect that the "path way" approach might be a bit anthropomorphic.Here we offered a different approach.We set out to investigate the evolutionary fitness changes from one local maximum , Psoriasis , to another , Atopie. Our hypothesis is that Psoriasis is at one extreme in the reaction of the evolution to invading micro organisms and Atopie at an other.So the vast chemical web called human being with numorous feedback and feed forward signals would then be tilted a bit in multidimensional Gene Space and the microarray technique would show us a glimpse of the involved genes. Keywords: Disease state analysis
Project description:Tape stripping has recently gained use for the study of the transcriptome of atopic dermatitis (AD), a common inflammatory skin disorder characterized by a defective epidermal barrier and perturbated immune response. Here, we performed BRB-seq (a low cost, multiplex-based, transcriptomic profiling technique) to study the epidermal transcriptome of AD patients and healthy controls from tape stripped skin samples.