Project description:Psoriasis is a common inflammatory skin disease characterized by aberrant inflammation and epidermal hyperplasia. Molecular mechanisms that regulate psoriasis-like skin inflammation remain to be fully understood. Here we show that the expression of Ovol1 transcription factor is upregulated in psoriatic skin, and its deletion results in aggravated psoriasis-like skin symptoms following stimulation with imiquimod (IMQ). Using bulk and single-cell RNA-sequencing, we identify molecular changes in the epidermal, fibroblast and immune cells of Ovol1-deficient skin that reflect altered course of epidermal differentiation and enhanced inflammatory responses. Furthermore, we provide evidence for excessive full-length IL-1 signaling in the microenvironment of IMQ-treated Ovol1-deficient skin that functionally contributes to immune cell infiltration and epidermal hyperplasia. Collectively, our study uncovers a protective role for Ovol1 in curtailing psoriasis-like inflammation and the associated skin pathology
Project description:Epidermal hyperplasia, a characteristic feature of psoriatic skin lesions, is epigenetically driven by Enhancer of Zeste homolog 2 (EZH2). EZH2 and EZH2-mediated trimethylation of histone H3 lysine 27 (H3K27me3) are both abnormally upregulated in psoriatic lesions. To identify microRNAs that could potentially target these epigenetic regulators we profiled miRNAs from psoriatic lesional skin in comparison with healthy skin. Analysis of the differentially expressed miRNAs revealed miR-101, as one of the most significant miRNA, consistently downregulated in psoriatic lesions compared to the healthy skin. A clear inverse correlation in the expression of miR-101 versus EZH2 was apparent in normal skin versus psoriatic lesional skin indicating that EZH2 is a potential target of miR-101, which was further confirmed by luciferase assay. Investigating the upstream effectors of the miR-101- EZH2 pathway in psoriasis, we identified the pro-inflammatory cytokine IL-17 as regulator of miR-101 expression. Here we propose a model, depicting a pathway triggered by IL-17 – mediated modulation of miR-101 expression, which in turn elicit sustained expression of EZH2, leading to enhanced keratinocyte proliferation and epidermal hyperplasia in psoriasis. Taken together, this indicates that miR-101 is a potential therapeutic target to alleviate the downstream effects of IL-17 mediated epidermal hyperplasia in psoriasis.
Project description:Transgenic overexpression of Pla2g2f at a level relevant to skin pathology display alopecia and psoriasis-like epidermal hyperplasia
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:Whether epidermal factors play a primary role in immune-mediated skin diseases such as psoriasis is unknown. We now show that the pro-differentiation transcription factor Grainyhead-like 3 (GRHL3), essential during epidermal development but dispensable in adult skin homeostasis, is required for barrier repair after adult epidermal injury. Consistent with activation of a GRHL3-regulated repair pathway in psoriasis, we find GRHL3 up-regulation in lesional skin where GRHL3 binds known epidermal differentiation gene targets. Furthermore, we show the functionality of this pathway in the Imiquimod mouse model of immune-mediated epidermal hyperplasia where loss of Grhl3 exacerbates the epidermal damage response, conferring greater sensitivity to disease induction, delayed resolution of epidermal lesions, and resistance to anti-IL-22 therapy. ChIP-seq and gene expression profiling studies show that while GRHL3 regulates differentiation genes both in development and during repair from immune-mediated damage, it targets distinct sets of genes in the two processes. In particular, GRHL3 suppresses a number of alarmin and other pro-inflammatory genes after immune injury. This study identifies a GRHL3-regulated epidermal barrier repair pathway that suppresses disease initiation and helps resolve existing lesions in immune-mediated epidermal hyperplasia. A single timepoint was assessed after physical injury of the epidermal barrier and two timepoints were assessed after immune mediated injury of the epidermis following Imiquimod treatment (psoriasis mouse model)
Project description:Psoriasis is a complex inflammatory disease resulting from the activation of T helper (Th) 1 and Th17 cells. Recent evidence suggests that abnormal activation of Toll-like receptors (TLRs) 7, 8 and 9 contributes to the initiation and maintenance of psoriasis. We have evaluated the effects of TLR antagonists on the gene expression profile in an IL-23-induced skin inflammation model in mice. Psoriasis-like skin lesions were induced in C57BL/6 mice by intradermal injection of IL-23 in the dorsum. Two TLR antagonists were compared: IMO-3100, an antagonist of TLRs 7 and 9, and IMO-8400, an antagonist of TLRs 7, 8 and 9, both of which previously have been shown to reduce epidermal hyperplasia in this model. Skin gene expression profiles of IL-23-induced inflammation were compared with or without TLR antagonist treatment. IL-23 injection resulted in alteration of 5100 gene probes (fold change ≥ 2, FDR < 0.05) including IL-17 pathways that are up-regulated in psoriasis vulgaris. Targeting TLRs 7, 8 and 9 with IMO-8400 resulted in modulation of more than 2300 mRNAs while targeting TLRs 7 and 9 with IMO-3100 resulted in modulation of more than 1900 mRNAs. Both agents strongly decreased IL-17A expression (>12-fold reduction), normalized IL-17 induced genes such as beta-defensin and CXCL1, and normalized aberrant expression of keratin 16 (indicating epidermal hyperplasia). These results suggest that IL-23-driven inflammation in mouse skin may be dependent on signaling mediated by TLRs 7, 8, and 9 and that these receptors represent novel therapeutic targets in psoriasis vulgaris and other diseases with similar pathophysiology. Expression profiles for mice with IL23-induced phenotype (psoriasisform) at baseline and after treatment with two doses of TLR7/8/9 antagonist and saline. Samples for nomal mice are also available
Project description:Cellular binary fate decisions require the progeny to silence genes associated with the alternative fate. The major subsets of alpha:beta T cells have been extensively studied as a model system for fate decisions. While the transcription factor RUNX3 is required for the initiation of Cd4 silencing in CD8 T cell progenitors, it is not required to maintain the silencing of Cd4 and other helper T lineage genes. The other runt domain containing protein, RUNX1, silences Cd4 in an earlier T cell progenitor, but this silencing is reversed whereas the gene silencing after RUNX3 expression is not reverse. Therefore, we hypothesized that RUNX3 and not RUNX1 recruits other factors that maintains the silencing of helper T lineage genes in CD8 T cells. To this end, we performed a proteomics screen of RUNX1 and RUNX3 to determine candidate silencing factors.
Project description:Epidermal barrier repair mechanisms activated in psoriasis lesions are likely involved in limiting the severity of this disease. We show that loss of grainyhead-like 3 (Grhl3), a pro-terminal differentiation factor in the epidermis, is sufficient to trigger greater sensitivity to and delayed resolution of epidermal lesions resulting from either physical or immune mediated barrier injury. After stimulation of Toll like receptors, the loss of Grhl3 resulted in increased epidermal damage with a striking increase in basal cell proliferation, hyperplasia of partially differentiated suprabasal layers, and a transcriptional profile highlighted by the overexpression of epidermal wound response and alarmin genes. This study reveals an important role for the epidermis in the initiation and recovery from immune-mediated lesions, and indicated that the epidermal regulator Grhl3 acts to both suppress disease initiation and resolve existing lesions. This work suggests that treatments focused on improving barrier function could be used preventatively and therapeutically in psoriasis. Whole skin was collected from E16.5 mouse backskins for Grhl3 ChIP. Adult epidermis for depilation and imiquimod experiments was seperated from dermis using dispase prior to Grhl3 ChIP.
Project description:Psoriasis is a chronic inflammatory skin disease characterized by marked proliferation of keratinocytes leading to pronounced epidermal hyperplasia, elongation of rete ridges and hyperkeratosis. The most common form of psoriasis, chronic plaque psoriasis (Psoriasis vulgaris), involves relatively stable occurrence and progression of sharply demarcated lesions, usually on the trunk and extremities, which share a combination of trademark histological features, including tortuous and dilated dermal capillaries, loss of the epidermal granular layer, and accumulation of neutrophils beneath parakeratotic scale. In this study, whole-genome transcriptional profiling was used to characterize gene expression in 4 lesional and uninvolved skin samples obtained from patients with stable chronic plaque psoriasis. Skin mRNA expression was analysed by microarray. Four individuals with chronic plaque psoriasis were enrolled. 6 mm punch biopsies were obtained under local anaesthesia (lidocaine) from uninvolved skin and a target plaque.
Project description:Using lineage-tracing in a well-established psoriasis-like mouse model with inducible epidermal deletion of c-Jun and JunB, we found that mutant HF-SCs survive and express a broad group of pro-inflammatory cytokines, whereas mutant inter-follicular epidermal cells (IFE) disappear over time. Mutant HF-SCs initiate epidermal hyperplasia and skin inflammation by priming neighboring non-mutant epidermal cells to acquire a psoriasis-like phenotype. To explore the molecular mechanisms that govern the behavior of these distinct mutant and non-mutant HF-SCs and IFE cell populations during psoriasis-like disease, RNA sequencing analyses of sorted GFP+, Tomato+ HF-SCs and b-KCs from DKO*-mT/mG mice.