Project description:Atopic dermatitis is a multifactorial allergic skin disease in humans and dogs. Genetic predisposition, immunologic hyperreactivity, a defective skin barrier and environmental factors play a role in its pathogenesis. The aim of this study was to analyze gene expression in the skin of dogs sensitized to house dust mite antigens. Skin biopsies were collected from six sensitized and six non-sensitized Beagle dogs from normal, non-treated skin before and six and 24 hours after challenge using skin patches with allergen or saline as a negative control. Transcriptome analysis was performed by the use of DNA microarrays and expression of selected genes was validated by quantitative real-time RT-PCR. Expression data was compared between groups (unpaired design). After 24 hours 597 differentially expressed genes were detected, 361 with higher and 226 with lower mRNA concentration in allergen treated skin of sensitized dogs compared to their saline-treated skin and compared to the control specimens. Functional annotation clustering, pathway-and co-citation analysis showed, that the genes with increased expression were involved in inflammation, wound healing and immune response. In contrast, genes with decreased expression in sensitized dogs were associated with differentiation and barrier function of the skin. As the sensitized dogs did not show differences in the untreated skin compared to controls, inflammation after allergen patch test probably led to a decrease in the expression of genes important for barrier formation. Our results further confirm the similar pathophysiology of human and canine atopic dermatitis and revealed genes previously not known to be involved in canine atopic dermatitis. 60 canine (dog) skin tissue samples; six sensitized and six non-sensitized Beagle dogs; samples collected before (0h), 6h and 24h after challenge with allergen; samples collected from a skin area treated with saline and from an area treated with allergen
Project description:Atopic dermatitis is a multifactorial allergic skin disease in humans and dogs. Genetic predisposition, immunologic hyperreactivity, a defective skin barrier and environmental factors play a role in its pathogenesis. The aim of this study was to analyze gene expression in the skin of dogs sensitized to house dust mite antigens. Skin biopsies were collected from six sensitized and six non-sensitized Beagle dogs from normal, non-treated skin before and six and 24 hours after challenge using skin patches with allergen or saline as a negative control. Transcriptome analysis was performed by the use of DNA microarrays and expression of selected genes was validated by quantitative real-time RT-PCR. Expression data was compared between groups (unpaired design). After 24 hours 597 differentially expressed genes were detected, 361 with higher and 226 with lower mRNA concentration in allergen treated skin of sensitized dogs compared to their saline-treated skin and compared to the control specimens. Functional annotation clustering, pathway-and co-citation analysis showed, that the genes with increased expression were involved in inflammation, wound healing and immune response. In contrast, genes with decreased expression in sensitized dogs were associated with differentiation and barrier function of the skin. As the sensitized dogs did not show differences in the untreated skin compared to controls, inflammation after allergen patch test probably led to a decrease in the expression of genes important for barrier formation. Our results further confirm the similar pathophysiology of human and canine atopic dermatitis and revealed genes previously not known to be involved in canine atopic dermatitis.
Project description:Exposure to dogs in early infancy has been shown to reduce the risk of childhood allergic disease development and dog-ownership is associated with a distinct house dust microbial exposure. Here we demonstrate, using murine models, that exposure of mice toM-BM- dog-associated house dust protects against ovalbumin or cockroach allergen mediated airway pathology. Protected animals exhibited significant reductions in the total number of airway T cells, down-regulation of Th2-related airway responses as well as mucin secretion. Following house dust exposure, the cecal microbiome of protected animals was extensively restructured with significant enrichment of, amongst others, Lactobacillus johnsonii. Supplementation of wild type animals with L. johnsonii protected them against both airway allergen challenge or infection with respiratory syncytial virus. L. johnsonii mediated protection wasM-BM- associated with significant reductions in the total number and proportion of activated CD11c+/CD11b+ and CD11c+/CD8+ cells, as well as significantly reduced airway Th2 cytokine expression. Our results reveal that exposure to dog-associated household dust results in protection against airway allergen challenge and a distinct GI microbiome composition. Moreover the study identifies L. johnsonii as a pivotal species within the gastrointestinal tract capable of influencing adaptive immunity at remote mucosal surfaces in a manner that is protective against a variety of respiratory insults. The G2 PhyloChip microarray platform (commercially available from Second Genome, Inc.) was used to profile cecal gut bacteria from 29 mice: 7 controls, 5 gavaged with dust from homes with pets, 5 gavaged with dust from homes with no pets, 4 CRA-challenged, 4 gavaged with L. johnsonii, and 4 gavaged with L. johnsonii prior to CRA challenge. The PhyloChip was also used to profile 1 house dust sample collected from a home with dogs
Project description:Exposure to dogs in early infancy has been shown to reduce the risk of childhood allergic disease development and dog-ownership is associated with a distinct house dust microbial exposure. Here we demonstrate, using murine models, that exposure of mice toM-BM- dog-associated house dust protects against ovalbumin or cockroach allergen mediated airway pathology. Protected animals exhibited significant reductions in the total number of airway T cells, down-regulation of Th2-related airway responses as well as mucin secretion. Following house dust exposure, the cecal microbiome of protected animals was extensively restructured with significant enrichment of, amongst others, Lactobacillus johnsonii. Supplementation of wild type animals with L. johnsonii protected them against both airway allergen challenge or infection with respiratory syncytial virus. L. johnsonii mediated protection wasM-BM- associated with significant reductions in the total number and proportion of activated CD11c+/CD11b+ and CD11c+/CD8+ cells, as well as significantly reduced airway Th2 cytokine expression. Our results reveal that exposure to dog-associated household dust results in protection against airway allergen challenge and a distinct GI microbiome composition. Moreover the study identifies L. johnsonii as a pivotal species within the gastrointestinal tract capable of influencing adaptive immunity at remote mucosal surfaces in a manner that is protective against a variety of respiratory insults. The G2 PhyloChip microarray platform (commercially available from Second Genome, Inc.) was used to profile cecal gut bacteria from 29 mice: 7 controls, 5 gavaged with dust from homes with pets, 5 gavaged with dust from homes with no pets, 4 CRA-challenged, 4 gavaged with L. johnsonii, and 4 gavaged with L. johnsonii prior to CRA challenge. The PhyloChip was also used to profile 1 house dust sample collected from a home with dogs
Project description:Exposure to dogs in early infancy has been shown to reduce the risk of childhood allergic disease development and dog-ownership is associated with a distinct house dust microbial exposure. Here we demonstrate, using murine models, that exposure of mice toM-BM- dog-associated house dust protects against ovalbumin or cockroach allergen mediated airway pathology. Protected animals exhibited significant reductions in the total number of airway T cells, down-regulation of Th2-related airway responses as well as mucin secretion. Following house dust exposure, the cecal microbiome of protected animals was extensively restructured with significant enrichment of, amongst others, Lactobacillus johnsonii. Supplementation of wild type animals with L. johnsonii protected them against both airway allergen challenge or infection with respiratory syncytial virus. L. johnsonii mediated protection wasM-BM- associated with significant reductions in the total number and proportion of activated CD11c+/CD11b+ and CD11c+/CD8+ cells, as well as significantly reduced airway Th2 cytokine expression. Our results reveal that exposure to dog-associated household dust results in protection against airway allergen challenge and a distinct GI microbiome composition. Moreover the study identifies L. johnsonii as a pivotal species within the gastrointestinal tract capable of influencing adaptive immunity at remote mucosal surfaces in a manner that is protective against a variety of respiratory insults. The G2 PhyloChip microarray platform (commercially available from Second Genome, Inc.) was used to profile cecal gut bacteria from 29 mice: 7 controls, 5 gavaged with dust from homes with pets, 5 gavaged with dust from homes with no pets, 4 CRA-challenged, 4 gavaged with L. johnsonii, and 4 gavaged with L. johnsonii prior to CRA challenge. The PhyloChip was also used to profile 1 house dust sample collected from a home with dogs
Project description:Barrier integrity is central to the maintenance of a healthy immunological homeostasis. Impaired skin barrier function is linked with enhanced allergen sensitization and the development of diseases such as atopic dermatitis (AD), which can precede the development of other allergic diseases such as food allergies and asthma. Epidemiological evidence indicates that children suffering from allergies have lower levels of dietary fibre-derived short-chain fatty acids (SCFA). Using an experimental model of AD, we report that a fermentable fibre-rich diet alleviates AD severity and systemic allergen sensitization. The gut-skin axis underpins this phenomenon through SCFA, which strengthen skin barrier integrity by altering mitochondrial metabolism of epidermal keratinocytes. SCFA promote keratinocyte differentiation and the production of key structural lipids, resulting in enhanced barrier function. Our results demonstrate that dietary fibre and SCFA mitigate AD by improving barrier integrity, ultimately limiting early systemic allergen sensitization and development of disease.
Project description:The aim of the study was to identify genes which are differentially expressed in the blood of dogs with canine atopic dermatitis (AD) before and after 6 months of allergen-specific immunotherapy (ASIT) in comparison to healthy control dogs. Diagnosis of AD was based on compatible history and clinical signs determined using Willemse and Prélaud diagnostic criteria, completed by Favrot criteria as follows: pruritus sine material, indoor lifestyle and the exclusion of other causes of pruritus ongoing for at least one year. Clinical diagnosis of atopic dermatitis was confirmed by serological allergy testing (IDEXX allergic panel test) and intradermal skin testing (Artuvetrin test set, Netherlands). In order to avoid the role of food antigens as a cause of the skin condition elimination diet was used for 6–8 weeks. No anti-inflammatory drugs were given for at least 3 weeks prior examination with serological test, intradermal test and blood collection. All dogs, which were classified to the investigated group had positive reactions in serological allergy testing and intradermal skin testing. Subsequently, subcutaneous allergen-specific immunotherapy was applied. Allergen extracts were prepared on the basis of the results of intradermal tests by the Artuvetrin company and were administered subcutaneously in increasing concentrations during 6 months according to the manufacturer's recommendations. Aside from gene regulation, this experiment also examined the participation of individual lymphocyte subpopulations (like: B, T, Th, Tc, Treg) and the level of interleukins in the blood of AD dogs before and after therapy.