Project description:miR-146a acts as a negative feedback regulator of inflammation. To investigate the role of miR-146a in psoriasis psoriasiform skin inflammation was indeuced in Mir-146a-/- and wild type mice (C57BL6J) by topical applciation of imiquimod (IMQ)-cream (Aldara). Gene expression profiling (Affymetrix) was used to identify transcriptomic changes associated with psoriasis-like skin inflammation in wild type vs. miR-146a -/-mice. A daily topical dose of 31.25 mg of Aldara cream (5% IMQ) was applied on the right ear of miR-146a -/- and C57BL/6 mice on three consecutive days to induce psorisis-like skin inflammation. Mice were sacrificed at day 4. Ear flaps were collected for total RNA extraction and hybridization on Affymatrix GeneTitan plate format Gene ST 2.1 (mouse).
Project description:miR-146a acts as a negative feedback regulator of inflammation. To investigate the role of miR-146a in psoriasis psoriasiform skin inflammation was indeuced in Mir-146a-/- and wild type mice (C57BL6J) by topical applciation of imiquimod (IMQ)-cream (Aldara). Gene expression profiling (Affymetrix) was used to identify transcriptomic changes associated with psoriasis-like skin inflammation in wild type vs. miR-146a -/-mice.
Project description:Purpose: To compare epidermal LC transcriptomes of control group (wild-type IMQ-untreated C57/BL6 mice) and IMQ group (wild-type IMQ-treated C57/BL6 mice). Results: KEGG pathway analysis implied that lesional LCs were highly enriched in several inflammatory signalling pathways, including cytokine-cytokine receptor interactions, Th1, Th2 and Th17 cell differentiation, tumor necrosis factor signalling and IL-17 signalling pathways, complement and coagulation cascades, and NOD-like receptor signalling and PI3K-Akt signalling pathways. Gene set enrichment analysis plots revealed enrichment of cytokine activity, chemoattractant activity, protein lipid complex binding, and low-density lipoprotein particle binding gene sets in LCs from IMQ+ mice compared with IMQ- mice. Conclusions: These results confirmed a proinflammatory role for epidermal LCs in the pathogenesis of psoriasis.
Project description:Imiquimod (IMQ) is a topical therapeutic immune activator that causes psoriasiform inflammation in mice. To determine if IMQ-induced inflammation and gene expression changes depended on the time of day in which treatment is administered, we performed gene expression profiling of dorsal mouse back skin by microarray after different durations of topical 1% IMQ treatment (control = no treatment, 6 hr, 24 hr, and 5 days of IMQ treatment) at different times of day (ZT01, ZT07, ZT09 = day-time treatment; ZT13 and ZT19 = night-time treatment). We also performed a time course after IMQ treatment by collecting mouse back skin after 0 (no treatment), 1, 2, 4, 6, and 24 hours post-treatment. Lastly, we determined gene expression changes in response to IMQ in mice deleted for the core circadian clock gene, Bmal1, after 0 (no treatment) and 24 hours post-1% IMQ compared to Wt (both treated and collected during the daytime at ZT09). The results of this study are important as they show that IMQ-induced activation of interferon sensitive genes are diurnal in Wt mice after 6 hours and 24 hours but not after 5 consecutive treatments. Furthermore, we find that interferon sensitive genes are induced more robustly in the skin of Bmal1 KO mice after 24 hr IMQ compared to Wt mice. These results are important for further understanding how the circadian clock regulates immune activation in response to the theraputic agent IMQ. In this dataset, we include the expression data obtained from 28 microarray samples, all of which were generated from whole back skin RNA samples pooled from 5-7 mice per sample.
Project description:Kallikrein-related peptidase 6 (KLK6) is a secreted serine protease hypothesized to promote inflammation via cleavage of protease-activated receptors (PAR)1 and PAR2. KLK6 levels are elevated in multiple inflammatory and autoimmune conditions, but no definitive role in pathogenesis has been established. Here, we show that skin-targeted overexpression of KLK6 causes generalized, severe psoriasiform dermatitis with spontaneous development of debilitating psoriatic arthritis-like joint disease. The psoriatic skin and joint phenotypes are reversed by normalization of skin KLK6 levels and attenuated following genetic elimination of PAR1 but not PAR2. Conservation of this regulatory pathway was confirmed in human psoriasis using vorapaxar, an FDA-approved PAR1 antagonist, on explanted lesional skin from psoriasis patients. Beyond defining a critical role for KLK6-PAR1 signaling in promoting psoriasis, our results demonstrate that KLK6-PAR1-mediated inflammation in the skin alone is sufficient to drive inflammatory joint disease. Further, we identify PAR1 as a promising cytokine-independent target in therapy of psoriasis and psoriatic arthritis.
Project description:We report the application of single-cell-RNA sequencing technology for high-throughput profiling of primary mouse epidermal cells. We use a topical toll-like receptor 7 agonist, Imiquimod (IMQ) to activate the skin immune system. We find that the proportion of most of the cell types are conserved after IMQ treatment. We identify many interferon-sensitive genes that are induced after 6 hours of IMQ treatment. This study provides a deeper understanding of the cell type-specific anti-viral gene expression response to chemical modulators such as IMQ.
Project description:Background: Imiquimod (IMQ) produces a cutaneous phenotype in mice frequently studied as an acute model of human psoriasis. Whether this phenotype depends on strain or sex has never been systematically investigated on a large scale. Such effects, however, could lead to conflicts among studies, while further impacting study outcomes and efforts to translate research findings. Methods: RNA-seq was used to evaluate the psoriasiform phenotype elicited by IMQ in both sexes of 7 mouse strains (C57BL/6J, BALB/cJ, CD1, DBA/1J, FVB/NJ, 129X1/SvJ and MOLF/EiJ). Results: In most strains, IMQ altered gene expression in a manner consistent with human psoriasis, partly due to innate immune activation and decreased homeostatic gene expression. The IMQ response of MOLF males was aberrant, however, with decreased expression of differentiation-associated genes (elevated in other strains). Key aspects of the IMQ response differed between the two most commonly studied strains (BALB/c and C57BL/6). Compared with BALB/c, the C57BL/6 phenotype showed increased expression of genes associated with DNA replication, IL-17A activation and CD8+ T cells, but decreased expression of genes associated with interferon signaling and CD4+ T cells. Surprisingly, although IMQ-induced expression shifts mirrored psoriasis, correspondence was similar or better for other human skin diseases (e.g., eschars, acne, atopic dermatitis). For BALB/c, MOLF, and 129X1 strains, genes altered by IMQ corresponded better to those altered in human skin infections or wounds compared with those altered in psoriasis lesions. Conclusions: These findings demonstrate strain-dependent aspects of IMQ dermatitis that warrant consideration in planning and interpreting experimental studies. We have further shown that IMQ does not uniquely model psoriasis but in fact triggers a core set of pathways active in diverse skin diseases. These observations challenge the view of IMQ dermatitis as a mouse phenotype uniquely appropriate for studying psoriasis as opposed to other human skin conditions.
Project description:The mechanisms underlying pruritus of imiquimod (IMQ)-induced psoriasis remain poorly understood. In this study, we investigated whether there are certain key signaling molecules downstream of the recently identified peptides mediating itch in the spinal cord. We investigated the changes in the trascriptome by performing RNAseq of cervical spinal cords in control and IMQ-induced psoriasis. Our study represents the detailed analysis of transcriptomes of spinal cord in chronic itch model with biologic replicates, generated by RNA-seq technology.