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:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Occupational and environmental exposure to polycyclic aromatic hydrocarbons (PAHs) has been suggested to provoke inflammatory and/or allergic disorders including asthma, rhinitis and dermatitis. The molecular mechanisms of this PAH-mediated inflammation remain to be clarified. Previous studies implied the involvement of PAHs as irritants and allergens, with the reactive oxygen species generated from the oxygenated PAHs believed to be an exacerbating factor. As well, the possibility exists that PAHs contribute to the pathogenesis through activation of aryl-hydrocarbon receptor (AhR)-mediated transcription, since PAHs are potent inducers of the AhR. To address this point, we generated transgenic mouse lines expressing the constitutive active form of the AhR in keratinocytes. In these lines of mice, the AhR activity was constitutively enhanced in the absence of ligands, so that any other direct effects of PAHs and their metabolites could be ignored. At birth, these transgenic mice were normal, but severe skin lesions with itching developed postnatally. The skin lesions were accompanied by inflammation and immunological imbalance and resembled typical atopic dermatitis. Our present study demonstrates that constitutive activation of the AhR pathway causes inflammatory skin lesions and suggests a new mechanism for the exacerbation of inflammatory diseases following exposure to occupational and environmental xenobiotics. Experiment Overall Design: transgenic mice expressing constitutive active form of AhR in keratinocytes vs. non-transgenic mice (wild type littermates)
Project description:Clinical overlaps between psoriasis and atopic dermatitis are sometimes undiscernible, and there is no consensus whether to treat the overlap phenotype as psoriasis or atopic dermatitis. We enrolled patients diagnosed with either psoriasis or atopic dermatitis, and clinically re-stratified them into classic psoriasis, classic atopic dermatitis, and the overlap phenotype between psoriasis and atopic dermatitis. We compared gene expression profiles of lesional and nonlesional skin biopsy tissues between the three comparison groups. Global mRNA expression and T-cell subset cytokine expression in the skin of the overlap phenotype were consistent with the profiles of psoriasis and different from the profiles of atopic dermatitis. Unsupervised k-means clustering indicated that the best number of distinct clusters for the total population of the three comparison groups was two, and the two clusters of psoriasis and atopic dermatitis were differentiated by gene expression. Our study suggests that clinical overlap phenotype between psoriasis and atopic dermatitis has dominant molecular features of psoriasis, and genomic biomarkers can differentiate psoriasis and atopic dermatitis at molecular levels in patients with a spectrum of psoriasis and 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:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.
Project description:Periostin is a matricellular protein known to be alternatively spliced to produce isoforms with a molecular weight of 78-91 kDa. In the extracellular matrix, periostin attach to cell surfaces and induce signaling via integrin-binding and participates in fibrillogenesis to organize collagen in the extracellular space. In the atopic diseases atopic dermatitis and asthma, periostin is known to participate in driving the disease-causing type 2 inflammation. The periostin isoforms expressed in these diseases and the implication of the alternative splicing events are unknown. Here we present two universal assays to map the expression of periostin isoforms on both the transcriptional (RT-qPCR) and translational (PRM-based mass spectrometry) level. We use these assays to study the splice profile of periostin in atopic dermatitis lesions from patients in active treatment vs. normal skin and in in vitro models of atopic dermatitis and asthma. All isoforms expect isoform 3 show decreased expression at the transcriptional level in AD lesions from patients treated with corticosteroids compared to normal skin. The isoforms display an elevated amount at the translational level indicating a delayed response in periostin level during treatment. Expression of the isoforms were upregulated in the in vitro models of atopic dermatitis and asthma at both the transcriptional and translational level with isoform 3 and 5 displaying the highest level of overexpression. Interestingly, the often overlooked isoform 9 and 10 behaved opposite to the other isoforms as they were equally or even less abundant in the disease models compared to the control, and they were identified in the normal skin samples but not in atopic dermatitis lesions. With the assays and findings presented in the publication connected to this dataset we can take further steps in mapping and understanding the role of periostin isoforms.