Psoriasis is a chronic inflammatory skin disease of unknown etiology. Although macrophages and dendritic cells (DCs) have been proposed to drive the psoriatic cascade, their largely overlapping phenotype hampered studying their respective role. Topical application of Imiquimod, a Toll-like receptor 7 agonist, induces psoriasis in patients and psoriasiform inflammation in mice. We showed that daily application of Imiquimod for 14 days recapitulated both the initiation and the maintenance phase of psoriasis. Based on our ability to discriminate Langerhans cells (LCs), conventional DCs, monocytes, monocyte-derived DCs and macrophages in the skin, we characterized their dynamics during both phases of psoriasis. During the initiation phase, neutrophils infiltrated the epidermis whereas monocytes and monocyte-derived DCs were predominant in the dermis. During the maintenance phase, LCs and macrophage numbers increased in the epidermis and dermis, respectively. LC expansion resulted from local proliferation, a conclusion supported by transcriptional analysis. Continuous depletion of LCs during the course of Imiquimod treatment aggravated chronic psoriatic symptoms as documented by an increased influx of neutrophils and a stronger inflammation. Therefore, by developing a mouse model that mimics the human disease more accurately, we established that LCs play a negative regulatory role during the maintenance phase of psoriasis.
Dynamics and Transcriptomics of Skin Dendritic Cells and Macrophages in an Imiquimod-Induced, Biphasic Mouse Model of Psoriasis.
Specimen part, Treatment
View SamplesDendritic cells (DC) are the most potent antigen-presenting cells of the immune system. In lymph nodes (LN), they are also believed to dispose of apoptotic cells, a critical function usually achieved by macrophages (M) in other tissues. We report a population of tolerogenic M located in the T cell zone of LN. T zone M (TZM) are long lived M seeded after birth and slowly replaced by blood monocytes. We show that TZM but not DC act as the only professional scavengers clearing apoptotic cells in the LN T cell zone. Importantly, we demonstrate that TZM prevent the capture of apoptotic cells by DC and the associated potential noxious activation of T cell immunity. We thus propose a new model in which efferocytosis and T cell activation are uncoupled processes handled by TZM and DC respectively.
T Cell Zone Resident Macrophages Silently Dispose of Apoptotic Cells in the Lymph Node.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Broad and Largely Concordant Molecular Changes Characterize Tolerogenic and Immunogenic Dendritic Cell Maturation in Thymus and Periphery.
Specimen part, Treatment
View SamplesThis series contains re-analyzed samples from GSE39555, GSE39556 and GSE15907.
Broad and Largely Concordant Molecular Changes Characterize Tolerogenic and Immunogenic Dendritic Cell Maturation in Thymus and Periphery.
Specimen part
View SamplesDendritic cells (DC) play critical roles in central and peripheral T cell tolerance. DC found in the steady-state periphery undergo an homeostatic, tolerogenic, maturation that promotes interaction with naive T cells and induction of abortive responses. In contrast, thymic DC are thought to exist solely in an immature state. In this study, we show that XCR1+ thymic DC constitutively mature into a stage characterized by high levels of molecules involved in T cell activation. This unanticipated mature stage corresponded to a third of the XCR1+ thymic DC and fully accounted for their ability to cross-present self-antigens to developing T cells. Transcriptomic analysis of the XCR1+ DC found in thymus and steady-state periphery revealed that their maturation involves profound and convergent changes. Unexpectedly, maturation resulted in down-regulation of genes conferring their specific function on XCR1+ DC. Paradoxically, upon maturation, central and peripheral tolerogenic XCR1+ DC up-regulated many genes thought to drive pro-inflammatory T-cell responses. These events occur independtly of type I interferons and of the microlofora, since the same maturation pattern is observed in XCR1+ tDcs from control, Ifnar1-KO and germ-free mice. Thus, our results reveal that thymic XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating for both central and peripheral tolerance induction by XCR1+ DC.
Broad and Largely Concordant Molecular Changes Characterize Tolerogenic and Immunogenic Dendritic Cell Maturation in Thymus and Periphery.
Specimen part, Treatment
View SamplesDendritic cells (DC) play critical roles in central and peripheral T cell tolerance. DC found in the steady-state periphery undergo an homeostatic, tolerogenic, maturation that promotes interaction with naive T cells and induction of abortive responses. In contrast, thymic DC are thought to exist solely in an immature state. In this study, we show that XCR1+ thymic DC constitutively mature into a stage characterized by high levels of molecules involved in T cell activation. This unanticipated mature stage corresponded to a third of the XCR1+ thymic DC and fully accounted for their ability to cross-present self-antigens to developing T cells. Transcriptomic analysis of the XCR1+ DC found in thymus and steady-state periphery revealed that their maturation involves profound and convergent changes. Unexpectedly, maturation resulted in down-regulation of genes conferring their specific function on XCR1+ DC. Paradoxically, upon maturation, central and peripheral tolerogenic XCR1+ DC up-regulated many genes thought to drive pro-inflammatory T-cell responses. Thus, our results reveal that thymic XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating for both central and peripheral tolerance induction by XCR1+ DC.
Broad and Largely Concordant Molecular Changes Characterize Tolerogenic and Immunogenic Dendritic Cell Maturation in Thymus and Periphery.
Specimen part, Treatment
View SamplesXCR1+ dendritic cells (DC) have been shown to excel in antigen cross-presentation for the activation of nave CD8 T cells. This property was reported to be associated to the subset of the XCR1+ DC expressing IL-12b upon ex vivo stimulation for 24 h with a mixture of CpG, IFN-, and GM-CSF (Lin ML et al. Proc Natl Acad Sci USA. 2008. PMID: 18272486). DC found in the steady-state non-lymphoid tissues undergo an homeostatic, tolerogenic, maturation and migrate to the draining lymph nodes to interact with naive autoreactive T cells and induction their peripheral tolerance. In contrast, spleen DC are thought to exist solely in an immature state. The aim of this study was to re-examine heterogeneity within steady state spleen XCR1+ DC, in particular examining whether this population encompass a fraction of mature DCs as assessed through their expression of CCR7 and/or the Il12b gene. Indeed, we show that a small fraction of XCR1+ spleen DC constitutively mature into two distinct but likely successive activation stages characterized as CCR7+ and CCR7+Il12b+ respectively, and correlated with increasing ability to cross-present antigen to nave CD8 T cells. Transcriptomic analysis of the subsets of XCR1+ DC found in steady state spleen unexpectedly showed that their homeostatic maturation was unexpectedly associated with up-regulated of many genes thought to drive pro-inflammatory T-cell responses and previously found to be commonly induced upon maturation of distinct DC subsets in response to stimulation by various microbial-type stimuli (Vu Manh TP et al. Eur J Immunol. 2013. PMID: 23553052). Thus, our results reveal that spleen XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating upon homeostatic, tolerogenic, DC maturation versus microbial-type stimuli-induced, immunogenic, DC maturation.
Broad and Largely Concordant Molecular Changes Characterize Tolerogenic and Immunogenic Dendritic Cell Maturation in Thymus and Periphery.
Specimen part
View SamplesThe goal of this experiment was to use global gene expression profiling to assess the global genetic reprogramming of spleen XCR1+ DC early after MCMV infection in vivo, using on Affymetrix Mouse Gene 1.0 ST Array.
Broad and Largely Concordant Molecular Changes Characterize Tolerogenic and Immunogenic Dendritic Cell Maturation in Thymus and Periphery.
Specimen part, Treatment
View SamplesThe goal of this experiment was to use global gene expression profiling to compare the global genetic reprogramming of spleen XCR1+ DC upon in vivo stimulation with a viral-type ligand, polyI:C which strongly induces type I interferons, versus with a ligand derived from an intracellular parasite which strongly induces IFN-g.
Broad and Largely Concordant Molecular Changes Characterize Tolerogenic and Immunogenic Dendritic Cell Maturation in Thymus and Periphery.
Specimen part, Treatment
View SamplesRNA-seq analysis was performed using RNA isolated from three tumor models (GL261 glioma, LLC Lewis lung carcinoma, B16F10 melanoma) implanted subcutaneousy in C57BL/6 mice, or in ICR scid mice. Mice were untreated or were treated with cyclophosphamide (CPA) given on a 6-day repeating metronomic schedule (CPA/6d), except as noted. Results from these global transcriptome analysis indicated substantial elevation of basal GL261 immune infiltration and strong activation by CPA/6d treatment of GL261 immune stimulatory pathways and their upstream regulators, but without preferential depletion of negative immune regulators compared to LLC and B16F10 tumors. In LLC tumors, where CPA/6d treatment was found to be anti-angiogenic, CPA/6d suppressed VEGFA target genes and down regulated cell adhesion and leukocyte transendothelial migration genes. In GL261 tumors implanted in adaptive immune-deficient scid mice, where CPA/6d-induced GL261 regression is incomplete and late tumor growth rebound can occur, T cell receptor signaling and certain cytokine-cytokine receptor responses seen in B6 mice were deficient. Extending the CPA treatment interval from 6 to 9 days (CPA/9d) - which results in a strong but transient natural killer cell response followed by early tumor growth rebound - induced fewer cytokines and increased expression of drug metabolism genes. Taken together, these findings elucidate molecular response pathways activated by intermittent metronomic CPA treatment and identify deficiencies that characterize immune-unresponsive tumor models and drug schedules. Overall design: RNA isolated from various tumor cell lines implanted s.c in C57BL/6 mice or scid mice, untreated or treated with cyclophosphamide (CPA) given on a metronomic schedule, were prepared and used for stranded or unstranded RNA-seq.
Metronomic cyclophosphamide activation of anti-tumor immunity: tumor model, mouse host, and drug schedule dependence of gene responses and their upstream regulators.
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