Project description:Transcriptional profiling of Homo sapiens inflammatory skin diseases (whole skin biospies): Psoriasis (Pso), vs Atopic Dermatitis (AD) vs Lichen planus (Li), vs Contact Eczema (KE), vs Healthy control (KO) In recent years, different genes and proteins have been highlighted as potential biomarkers for psoriasis, one of the most common inflammatory skin diseases worldwide. However, most of these markers are not psoriasis-specific but also found in other inflammatory disorders. We performed an unsupervised cluster analysis of gene expression profiles in 150 psoriasis patients and other inflammatory skin diseases (atopic dermatitis, lichen planus, contact eczema, and healthy controls). We identified a cluster of IL-17/TNFα-associated genes specifically expressed in psoriasis, among which IL-36γ was the most outstanding marker. In subsequent immunohistological analyses IL-36γ was confirmed to be expressed in psoriasis lesions only. IL-36γ peripheral blood serum levels were found to be closely associated with disease activity, and they decreased after anti-TNFα-treatment. Furthermore, IL-36γ immunohistochemistry was found to be a helpful marker in the histological differential diagnosis between psoriasis and eczema in diagnostically challenging cases. These features highlight IL-36γ as a valuable biomarker in psoriasis patients, both for diagnostic purposes and measurement of disease activity during the clinical course. Furthermore, IL-36γ might also provide a future drug target, due to its potential amplifier role in TNFα- and IL-17 pathways in psoriatic skin inflammation. In recent years, different genes and proteins have been highlighted as potential biomarkers for psoriasis, one of the most common inflammatory skin diseases worldwide. However, most of these markers are not psoriasis-specific but also found in other inflammatory disorders. We performed an unsupervised cluster analysis of gene expression profiles in 150 psoriasis patients and other inflammatory skin diseases (atopic dermatitis, lichen planus, contact eczema, and healthy controls). We identified a cluster of IL-17/TNFα-associated genes specifically expressed in psoriasis, among which IL-36γ was the most outstanding marker. In subsequent immunohistological analyses IL-36γ was confirmed to be expressed in psoriasis lesions only. IL-36γ peripheral blood serum levels were found to be closely associated with disease activity, and they decreased after anti-TNFα-treatment. Furthermore, IL-36γ immunohistochemistry was found to be a helpful marker in the histological differential diagnosis between psoriasis and eczema in diagnostically challenging cases. These features highlight IL-36γ as a valuable biomarker in psoriasis patients, both for diagnostic purposes and measurement of disease activity during the clinical course. Furthermore, IL-36γ might also provide a future drug target, due to its potential amplifier role in TNFα- and IL-17 pathways in psoriatic skin inflammation.
Project description:To understand the development of new psoriasis lesions, we studied a group of moderate-to-severe psoriasis patients who experienced a relapse after ceasing efalizumab (anti-CD11a, Raptiva, Genentech). There were increased CD3+ T cells, neutrophils, CD11c+ and CD83+ myeloid DCs, but no increase in CD1c+ resident myeloid DCs. In relapsed lesions, there were many CD11c+CD1c-, inflammatory myeloid DCs identified by TNFSF10/TRAIL, TNF, and iNOS. CD11c+ cells in relapsed lesions co-expressed CD14 and CD16 in situ. Efalizumab induced an improvement in many psoriasis genes, and during relapse, the majority of these genes reversed back to a lesional state. Gene Set Enrichment Analysis (GSEA) of the transcriptome of relapsed tissue showed that many of the gene sets known to be present in psoriasis were also highly enriched in relapse. Hence, on ceasing efalizumab, T cells and myeloid cells rapidly enter the skin to cause classic psoriasis. To determine the transcsriptome of skin samples in 4 responding patients who relapsed after receiving efalizumab for treatment of psoriasis, using paired baseline non-lesional (NL, n=2); lesional (LS, n=4);week 12 post-treatment (week 12, n=4), and relapse (n=4). Comparison of mean gene expression of each group at baseline, and considering treatment effect
Project description:To understand the development of new psoriasis lesions, we studied a group of moderate-to-severe psoriasis patients who experienced a relapse after ceasing efalizumab (anti-CD11a, Raptiva, Genentech). There were increased CD3+ T cells, neutrophils, CD11c+ and CD83+ myeloid DCs, but no increase in CD1c+ resident myeloid DCs. In relapsed lesions, there were many CD11c+CD1c-, inflammatory myeloid DCs identified by TNFSF10/TRAIL, TNF, and iNOS. CD11c+ cells in relapsed lesions co-expressed CD14 and CD16 in situ. Efalizumab induced an improvement in many psoriasis genes, and during relapse, the majority of these genes reversed back to a lesional state. Gene Set Enrichment Analysis (GSEA) of the transcriptome of relapsed tissue showed that many of the gene sets known to be present in psoriasis were also highly enriched in relapse. Hence, on ceasing efalizumab, T cells and myeloid cells rapidly enter the skin to cause classic psoriasis.
Project description:Our group recently described a population of antigen presenting cells that appear to be critical in psoriasis pathogenesis, termed inflammatory myeloid dendritic cells (CD11c+ BDCA1-). Triggering receptor expressed on myeloid cells type-1 (TREM-1) signaling was a major canonical pathway in the published transcriptome of these cells. TREM-1 is a member of the immunoglobulin superfamily, active through the DAP12 signaling pathway, with an unknown ligand. Activation through TREM-1 induces inflammatory cytokines including IL-8, MCP/CCL2 and TNF. We now show that TREM-1 was expressed in the skin of healthy and psoriatic patients, and there was increased soluble TREM-1 in the circulation of psoriasis patients. In psoriasis lesions, TREM-1 was co-localized with dendritic cells as well as CD31+ endothelial cells. TREM-1 expression was reduced with successful NB-UVB, etanercept and anti-IL-17 treatments. An in vitro model of PGN-activated monocytes as inflammatory myeloid DCs was developed to study TREM-1 blockade, and treatment with a TREM-1 blocking chimera decreased allogeneic Th17 activation, as well as IL-17 production. Furthermore, TREM-1 blockade of ex vivo psoriatic dendritic cells in an alloMLR also showed a decrease in IL-17. Together, these data suggest that the TREM-1 signaling pathway offers a novel therapeutic target to prevent the effects of inflammatory myeloid DCs in psoriasis. Monocytes were isolated by plastic adherence, treated with TLR agonists overnight, washed twice and harvested in RTL-buffer. RNA was extracted and processed for microarray. 3 groups and 3 replicates with a paired structure across replicates
Project description:Our group recently described a population of antigen presenting cells that appear to be critical in psoriasis pathogenesis, termed inflammatory myeloid dendritic cells (CD11c+ BDCA1-). Triggering receptor expressed on myeloid cells type-1 (TREM-1) signaling was a major canonical pathway in the published transcriptome of these cells. TREM-1 is a member of the immunoglobulin superfamily, active through the DAP12 signaling pathway, with an unknown ligand. Activation through TREM-1 induces inflammatory cytokines including IL-8, MCP/CCL2 and TNF. We now show that TREM-1 was expressed in the skin of healthy and psoriatic patients, and there was increased soluble TREM-1 in the circulation of psoriasis patients. In psoriasis lesions, TREM-1 was co-localized with dendritic cells as well as CD31+ endothelial cells. TREM-1 expression was reduced with successful NB-UVB, etanercept and anti-IL-17 treatments. An in vitro model of PGN-activated monocytes as inflammatory myeloid DCs was developed to study TREM-1 blockade, and treatment with a TREM-1 blocking chimera decreased allogeneic Th17 activation, as well as IL-17 production. Furthermore, TREM-1 blockade of ex vivo psoriatic dendritic cells in an alloMLR also showed a decrease in IL-17. Together, these data suggest that the TREM-1 signaling pathway offers a novel therapeutic target to prevent the effects of inflammatory myeloid DCs in psoriasis.
Project description:Background: Previous work has identified CD11c+CD1c- dendritic cells (DCs) as the major 'inflammatory' dermal DC population in psoriasis vulgaris and CD1c+ DCs as the 'resident' cutaneous DC population. Objective: To further define molecular differences between these two myeloid dermal DC populations. Methods: Inflammatory and resident DCs were single-cell sorted from psoriasis lesional skin biopsies, and gene array expression profiling was performed. Results were confirmed with RT-PCR, flow cytometry, immunohistochemistry, and double label immunofluorescence. Pooled human keratinocytes were cultured for functional studies. Results: TNF-related apoptosis-inducing ligand (TRAIL), Toll-like receptors (TLRs) 1 and 2, S100A12/EN-RAGE, CD32, and many other inflammatory products were selectively expressed in inflammatory DCs than in resident DCs. Flow cytometry and immunofluorescence confirmed higher protein expression on CD1c- versus CD1c+ DCs. TRAIL receptor, death receptor 4 (DR4), was expressed on basal keratinocytes and blood vessels, and in vitro culture of keratinocytes with rh-TRAIL induced CCL20 leukocyte chemokine. Conclusion: CD11c+CD1c- inflammatory DCs in psoriatic lesional skin express a wide range of inflammatory molecules compared to skin resident CD1c+ DCs. Some molecules made by inflammatory DCs, including TRAIL, could have direct effects on keratinocytes or other skin cell types to promote disease pathogenesis. Shave biopsies were cultured overnight in dispase to remove the epidermis. Dermis was cultured for 36-48 hours to obtain dermal single cell suspensions. These cells were stained with HLA-DR, CD11c, BDCA-1 (DCs) and FACS-sorted into HLA-DR+11c+BDCA-1+, HLA-DR+11c+BDCA-1- populations into Trizol. RNA was extracted and processed for microarray. 2 dependent groups.
Project description:Background: Previous work has identified CD11c+CD1c- dendritic cells (DCs) as the major ”inflammatory” dermal DC population in psoriasis vulgaris and CD1c+ DCs as the “resident” cutaneous DC population. Objective: To further define molecular differences between these two myeloid dermal DC populations. Methods: Inflammatory and resident DCs were single-cell sorted from psoriasis lesional skin biopsies, and gene array expression profiling was performed. Results were confirmed with RT-PCR, flow cytometry, immunohistochemistry, and double label immunofluorescence. Pooled human keratinocytes were cultured for functional studies. Results: TNF-related apoptosis-inducing ligand (TRAIL), Toll-like receptors (TLRs) 1 and 2, S100A12/EN-RAGE, CD32, and many other inflammatory products were selectively expressed in inflammatory DCs than in resident DCs. Flow cytometry and immunofluorescence confirmed higher protein expression on CD1c- versus CD1c+ DCs. TRAIL receptor, death receptor 4 (DR4), was expressed on basal keratinocytes and blood vessels, and in vitro culture of keratinocytes with rh-TRAIL induced CCL20 leukocyte chemokine. Conclusion: CD11c+CD1c- inflammatory DCs in psoriatic lesional skin express a wide range of inflammatory molecules compared to skin resident CD1c+ DCs. Some molecules made by inflammatory DCs, including TRAIL, could have direct effects on keratinocytes or other skin cell types to promote disease pathogenesis.
Project description:Psoriasis is a chronic, debilitating, immune-mediated inflammatory skin disease. As IFN-gamma is involved in many cellular processes, including activation of T cells and dendritic cells (DCs), antigen processing and presentation, cell adhesion and trafficking, and cytokine and chemokine production, IFN-gamma-producing Th1 cells were proposed to be integral to the pathogenesis of psoriasis. Recently, IFN-gamma was shown to enhance IL-23 and IL-1 production by DCs and subsequently induce Th17 cells, important contributors to the inflammatory cascade in psoriasis lesions. To determine if IFN-gamma indeed induces the pathways leading to the development of psoriasis lesions, a single intradermal injection of IFN-gamma was administered to an area of clinically normal, non-lesional skin of psoriasis patients and biopsies were collected 24 hours later. Although there were no visible changes in the skin, IFN-gamma induced molecular and histological features characteristic of psoriasis lesions. IFN-gamma increased a number of differentially expressed genes in the skin, including many chemokines concomitant with an influx of T cells and inflammatory DCs. Furthermore, inflammatory DC products TNF, iNOS, IL-23, and TRAIL were present in IFN-gamma-treated skin. Thus, IFN-gamma, which is significantly elevated in non-lesional skin compared to healthy skin, appears to be a key pathogenic cytokine that can induce the inflammatory cascade in psoriasis. RNA was isolated from whole skin punch biopsies of either healthy or non-lesional psoraisis patients at baseline or 24 hours after placebo or IFN-g injection.