Project description:Environmental stimuli are known to contribute to psoriasis pathogenesis and that of other autoimmune diseases, but the mechanism is unknown. Here we show that the aryl hydrocarbon receptor (AhR), a transcription factor that senses environmental stimuli, modulates pathology in psoriasis. AhR-activating ligands reduced inflammation in the lesional skin of psoriasis patients, whereas AhR antagonists upregulated inflammation. Similarly, AhR signaling via the endogenous FICZ ligand reduced the inflammatory response in the imiquimod-induced model of psoriasis and AhR deficient mice exhibited a substantial exacerbation of the disease, compared to AhR sufficient controls. Non-haematopoietic cells, in particular keratinocytes, were responsible for this hyper-inflammatory response, which involved increased reactivity to IL-1beta and upregulation of AP-1 family members of transcription factors. Thus, our data suggest a critical role for AhR in the regulation of inflammatory responses and open the possibility for novel therapeutic strategies in chronic inflammatory disorders. Total RNA obtained from skin explants taken from psoriatic patients or healthy donors cultured in the presence of AhR agonist or antagonist
Project description:CaMK4 has an important function in autoimmune diseases, and the contribution of CaMK4 in psoriasis remains obscure. Here, we show that CaMK4 expression is significantly increased in psoriatic lesional skin from psoriasis patients compared to healthy human skin as well as inflamed skin from an imiquimod (IMQ)-induced mouse model of psoriasis compared to healthy mouse skin. Camk4-deficient (Camk4−/−) mice treated with IMQ exhibit reduced severity of psoriasis compared to wild-type (WT) mice. There are more macrophages and fewer IL-17A+γδ TCR+ cells in the skin of IMQ-treated Camk4−/− mice compared to IMQ-treated WT mice. CaMK4 inhibits IL-10 production by macrophages, thus allowing excessive psoriatic inflammation. Deletion of Camk4 in macrophages alleviates IMQ-induced psoriatic inflammation in mice. In keratinocytes, CaMK4 inhibits apoptosis as well as promotes cell proliferation and the expression of pro-inflammatory genes such as S100A8 and CAMP. Taken together, these data indicate that CaMK4 regulates IMQ-induced psoriasis by sustaining inflammation and provides a potential target for psoriasis treatment.
Project description:[original Title] Comparison of expression data of primary murine melanocytes from aryl hydrocarbon deficient mice and corresponding wild-type C57BL/6 mice Melanin is produced exclusively by melanocytes and melanogenesis is the vital response to protect skin cells against Ultraviolet B (UVB)-induced DNA damage. The aryl hydrocarbon receptor (AhR) is a transcription factor, which may be involved in the physiological tanning response. Normal murine melanocytes express functional AhR. We tested gene expression in WT versus AhR-deficient mice primary murine melanocytes, isolated from the skin and cultivated for several passages. Skin epidermal cells from 2 individual C57BL/6 mice and 2 individual AhR-deficient mice (deletion of exon2, AhRtm1Bra) were grown for 6-8 weeks in selection medium to propagate melanocytes.
Project description:Environmental stimuli are known to contribute to psoriasis pathogenesis and that of other autoimmune diseases, but the mechanism is unknown. Here we show that the aryl hydrocarbon receptor (AhR), a transcription factor that senses environmental stimuli, modulates pathology in psoriasis. AhR-activating ligands reduced inflammation in the lesional skin of psoriasis patients, whereas AhR antagonists upregulated inflammation. Similarly, AhR signaling via the endogenous FICZ ligand reduced the inflammatory response in the imiquimod-induced model of psoriasis and AhR deficient mice exhibited a substantial exacerbation of the disease, compared to AhR sufficient controls. Non-haematopoietic cells, in particular keratinocytes, were responsible for this hyper-inflammatory response, which involved increased reactivity to IL-1beta and upregulation of AP-1 family members of transcription factors. Thus, our data suggest a critical role for AhR in the regulation of inflammatory responses and open the possibility for novel therapeutic strategies in chronic inflammatory disorders. Total RNA obtained from skin explants taken from AhR heterozygous or knock-out mice treated pericutaneously with imiquimod for 0 and 2d.
Project description:[original Title] Comparison of expression data of primary murine melanocytes from aryl hydrocarbon deficient mice and corresponding wild-type C57BL/6 mice Melanin is produced exclusively by melanocytes and melanogenesis is the vital response to protect skin cells against Ultraviolet B (UVB)-induced DNA damage. The aryl hydrocarbon receptor (AhR) is a transcription factor, which may be involved in the physiological tanning response. Normal murine melanocytes express functional AhR. We tested gene expression in WT versus AhR-deficient mice primary murine melanocytes, isolated from the skin and cultivated for several passages.
Project description:Objectives: To understand the crosstalk between the immune system and keratinization in psoriatic skin, using a systems biology approach based on transcriptomics, proteomics and microbiome profiling. Methods: We collected the skin tissue biopsies and swabs in both lesion and non-lesion skin of 13 patients with psoriasis (PsO), 15 patients with psoriatic arthritis (PsA), and healthy skin from 12 patients with ankylosing spondylitis (AS). We performed transcriptome sequencing and metagenomics profiling on the local skin sites to study the similarities and differences in the molecular profiles between the three conditions. To assess the systemic nature of the disease, we performed a high-throughput proteome profiling to study the profiles of proteins circulating in the serum of the same donors. Results: We found that lesion and non-lesional samples were remarkably different in terms of their transcriptome profiles. Functional annotation of differentially expressed genes (DEGs) showed a major enrichment in neutrophil activation. By using co-expression gene networks, we identified a gene module that was associated with local psoriasis severity at the site of biopsy. From this module, we extracted a “core” set of genes that were functionally involved in neutrophil activation, epidermal cell differentiation and response to bacteria. Skin microbiome analysis revealed that the abundance of Enhydrobacter, Micrococcus and Leptotrichia were significantly correlated with the “core network” of genes. We further identified 39 circulating proteins from the serum that were significantly correlated with the corresponding local skin gene expression, highlighting systemic aberrations due to skin disease. Integration of “core” genes identified from skin with circulating protein profiles revealed PI3 as a key biomarker for psoriasis. Conclusions: We identified a core network that regulates inflammation and hyper-keratinization in psoriatic skin, and is associated with local disease severity and microbiome composition. Multi-omics analysis identified PI3 as a psoriasis-specific biomarker for disease severity and potential target for treatment strategies.
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that have emerged as central regulators of gene expression and powerful biomarkers of disease. Much is yet unknown about their role in psoriasis pathology. To globally characterize the miRNAome of psoriatic skin, skin biopsies were collected from psoriatic cases (n = 75) and non-psoriatic controls (n = 57) and RNA sequenced. Count data was meta-analyzed with a previously published dataset (cases, n = 24, controls, n = 20), increasing the number of psoriatic cases four-fold from previously published studies. Differential gene expression analyses were performed comparing lesional psoriatic (PP), non-lesional psoriatic (PN) and control (NN) skin. Further, functional enrichment and cell-specific analyses were performed. Across all contrasts, we identified 439 significantly differentially expressed miRNAs (DEMs), of which 127 were novel for psoriasis and 11 were related to disease severity. Meta-analyses identified 20 DEMs between PN and NN, suggesting an inherent change in the constitution of all skin in psoriasis. By integrating the miRNA transcriptome with mRNA target interactions, we identified several functionally enriched terms, including ‘thyroid hormone signaling’, ‘insulin resistance’ and various infectious diseases. Cell specific expression analyses revealed that the upregulated DEMs were enriched in epithelial and immune cells. This study provides the most comprehensive overview of the miRNAome in psoriatic skin to date and identifies a miRNA signature related to psoriasis severity. Our results may represent molecular links between psoriasis and related comorbidities and have outlined potential directions for future functional studies to identify biomarkers and treatment targets.
Project description:To establish the role of PD-L1 expression on Langerhans cells and its influence on psoriatic skin inflammation, we isolated Langerhans cells from harvested ears of wild type mice treated with Vaseline or Imiquimod. We then determined the gene expression profile of isolated Langerhans cells from the different groups at a single time point using data from RNA-seq. The experiment was performed in duplicate.