Project description:The polyphenol resveratrol has anti-inflammatory effects in various cells, tissues, animals and human settings of low-grade inflammation. Psoriasis is a disease of both localized and systemic low-grade inflammation. The Sirtuin1 enzyme thought to mediate the effects of resveratrol is present in skin and resveratrol is known to downregulate NF-κB; a major contributor in the development of psoriasis. Consequently we investigated whether resveratrol has an effect on an Imiquimod induced psoriasis-like skin inflammation in mice and sought to identify candidate genes, pathways and interleukins mediating the observed effects. The study consisted of three treatment groups: A control group, an Imiquimod group and an Imiquimod+resveratrol group. Psoriasis severity was assessed using elements of the Psoriasis Area Severity Index, actual skin thickness measurements, and histological examination. We performed an RNA microarray from lesional skin and afterwards Ingenuity pathway analysis to identify affected signalling pathways. Our microarray was compared to a previously deposited microarray to determine if gene changes were psoriasis-like, and to a human microarray to determine if findings could be relevant in a human setting. Imiquimod treatment induced a psoriasis-like skin inflammation. Resveratrol significantly diminished the severity of the psoriasis-like skin inflammation. The RNA microarray revealed a psoriasis-like gene expression-profile in the Imiquimod treated group, and highlighted several resveratrol dependent changes in relevant genes, such as increased expression of genes associated with retinoic acid stimulation and reduced expression of genes involved in IL-17 dependent pathways (e.g.IL-17A, IL-17F,IL-23p19 ). Quantitative PCR confirmed a resveratrol dependent decrease in mRNA levels of IL-17A and IL-19; both central in developing psoriasis. In conclusion, resveratrol ameliorates psoriasis, and changes in expression of retinoic acid stimulated genes, IL-17 signalling pathways, IL-17A and IL-19 mRNA levels in a beneficial manner suggests it might have a role in the treatment of psoriasis and should be explored further in a human setting.
Project description:Increased intestinal permeability can exacerbate psoriasis, a systemic inflammatory disease with complex pathogenesis. Using a mouse model of psoriasis elicited by the TLR7 ligand imiquimod, we found that psoriatic dermatitis was accompanied by small-intestinal inflammatory changes associated with eosinophil degranulation which led to impaired intestinal barrier integrity. Inflammatory responses in the skin and small intestine were accelerated in mice that are prone to eosinophil degranulation. Caco-2 human intestinal epithelial cells treated with media containing eosinophil granule proteins exhibited signs of inflammation and damage. Imiquimod-induced skin and intestinal inflammatory changes were attenuated in eosinophil-deficient mice, and this attenuation was counteracted by eosinophil transfer. Imiquimod levels and eosinophil distribution were positively correlated in the intestine. TLR7-deficient mice did not show intestinal eosinophil degranulation and exhibited attenuated skin and small-intestinal inflammation following imiquimod application. These results suggest a TLR7-dependent bidirectional skin-to-gut communication in psoriatic inflammation, and that intestinal inflammatory changes can accelerate psoriasis.
Project description:We analyzed epidermal samples from keratinocyte-specific knockout Mettl3 (K14CreERT2;Mettl3fl/fl) mice and their controls (Mettl3fl/fl) in imiquimod-induced psoriasis-like skin lesions. Briefly, we established an imiquimod-induced psoriasis model in K14CreERT2;Mettl3fl/fl mice and their controls after tamoxifen injection, and epidermal samples were separated and collected from the skin lesions of the mice after 3 or 6 days of modeling (n=3 per group). The aim of this study was to investigate the mechanism by which Mettl3-mediated epidermal m6A methylation affects skin inflammation.
Project description:Vanillin is one of the most widely used flavouring products worldwide. Psoriasis is a chronic inflammatory skin disorder. Here we analyzed the effect of vanillin on imiquimod (IMQ)-induced psoriatic skin inflammation in mice.
Project description:Psoriasis is a chronic inflammatory skin disorder that is predominantly characterized by sharply demarcated chronic erythematous plaques. Although its etiological mechanisms are largely unknown, recent evidence suggests that the topical application of imiquimod (IMQ) cream causes psoriasis-like skin inflammation in humans and mice. Skin examined 4 hours after IMQ cream treatment. Results provide insight into the role of each knockout mice phenotype in the response to IMQ-induced psoriasis model.
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: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:TREX2 is a keratinocyte specific 3â-deoxyribonuclease that participates in the maintenance of skin homeostasis upon damage. This transcriptome analysis identified multiple genes and pathways deregulated by TREX2 loss in the IMQ-induced psoriasis-like model in mouse skin. mRNA sequencing of 5 biological replicates of skin from wild-type mice treated with Imiquimod and 6 of Trex2 knockout mice treated with Imiquimod
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: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).