Project description:IL-17A is a pro-inflammatory cytokine that promotes host defense against infections and contributes to the pathogenesis of chronic inflammatory diseases. Dendritic cells (DC) are antigen-presenting cells responsible for adaptive immune responses. Here, we report that IL-17A induces intense remodeling of lipid metabolism in human monocyte-derived DC, as revealed by microarrays analysis. In particular NR1H3/LXR-a and its target genes were significantly upregulated in response to IL-17A. IL-17A induced accumulation of Oil Red O-positive lipid droplets in DC leading to the generation of lipid-laden DC. A lipidomic study established that all the analyzed lipid species, i.e phospholipids, cholesterol, triglycerides, cholesteryl esters were elevated in IL-17A-treated DC. The increased expression of membrane lipid transporters in IL-17A-treated DC as well as their enhanced ability to uptake the fatty acid Bodipy-FL-C16 suggested that lipid uptake was the main mechanism responsible for lipid accumulation in response to IL-17A. IL-17A-induced lipid laden DC were able to stimulate allogeneic T cell proliferation in vitro as efficiently as untreated DC, indicating that IL-17A-treated DC are potently immunogenic. This study, encompassed in the field of immunometabolism, points out for the first time IL-17A as a modulator of lipid metabolism in DC and provides a rationale to delineate the importance of lipid-laden DC in IL-17A-related inflammatory diseases. We used microarrays analysis to understand the impact of IL-17A on human monocyte-derived human dendritic cells. We found overexpression of many genes involved in lipid metabolism in IL-17A-treated dendritic cells compared to untreated dendritic cells. In particular NR1H3/LXR-a and its target genes were significantly upregulated in response to IL-17A. IL-17A induced accumulation of Oil Red O-positive lipid droplets in DC leading to the generation of lipid-laden DC. A lipidomic study established that all the analyzed lipid species, i.e phospholipids, cholesterol, triglycerides, cholesteryl esters were elevated in IL-17A-treated DC. The increased expression of membrane lipid transporters in IL-17A-treated DC as well as their enhanced ability to uptake the fatty acid Bodipy-FL-C16 suggested that lipid uptake was the main mechanism responsible for lipid accumulation in response to IL-17A. IL-17A-induced lipid laden DC were able to stimulate allogeneic T cell proliferation in vitro as efficiently as untreated DC, indicating that IL-17A-treated DC are potently immunogenic. This study, encompassed in the field of immunometabolism, points out for the first time IL-17A as a modulator of lipid metabolism in DC and provides a rationale to delineate the importance of lipid-laden DC in IL-17A-related inflammatory diseases. RNA was extracted from untreated in vitro-generated DC at day 0 (DC, 4 biological replicates ) or DC cultured for 12 days with IL-17A, in the absence or presence of IFN-g (DC-17 and DC-G17, 5 biological replicates)
Project description:Asthmatics have elevated levels of IL-17A compared to healthy controls. IL-17A is likely to contribute to reduced corticosteroid sensitivity of human airway epithelium. Here, we aimed to investigate the mechanistic underpinnings of this reduced sensitivity in more detail. Differentiated primary human airway epithelial cells (hAECs) were exposed to IL-17A in the absence or presence of dexamethasone. Cells were then collected for RNA sequencing analysis or used for barrier function experiments. Mucus was collected for volume measurement and basal medium for cytokine analysis. 2861 genes were differentially expressed by IL-17A (Padj<0.05), of which the majority was not sensitive to dexamethasone (<50% inhibition). IL-17A did inhibit canonical corticosteroid genes, such as HSD11B2 and FKBP5 (p<0.05). Inflammatory and goblet cell metaplasia markers, cytokine secretion and mucus production were all induced by IL-17A, and these effects were not prevented by dexamethasone. Dexamethasone did reverse IL-17A-stimulated epithelial barrier disruption, and this was associated with gene expression changes related to cilia function and development. We conclude that IL-17A induces function-specific corticosteroid-insensitivity. Whereas inflammatory response genes and mucus production in primary hAECs in response to IL-17A were corticosteroid-insensitive, corticosteroids were able to reverse IL-17A-induced epithelial barrier disruption.
Project description:Human brain development depends on the coordinated interaction of diverse cell types and extracellular matrix (ECM) components, essential for proper neurogenesis and cortical organization. Epidemiological and animal studies demonstrated that maternal immune activation (MIA) disrupts brain development, impairing neurogenesis and increasing the risk of neurodevelopmental disorders (NDDs), including autism spectrum disorder and schizophrenia. However, the cellular and molecular mechanisms by which MIA impacts human cortical development remain poorly understood. Here, we introduce a 3D ex vivo culture system, termed 'cerebroids,' derived from dorsolateral prefrontal cortex of human fetal brain tissue, which faithfully preserves key developmental processes, critical cellular diversity and structural integrity of the developing human cortex. Using this platform, we show that IL-17A, a cytokine strongly implicated in NDDs, induces premature cortical folding, increases cortical thickness, and accelerates neurogenesis and neuronal maturation. Transcriptomic and proteomic analyses reveal that IL-17A significantly dysregulates ECM-related pathways, including upregulation of proteoglycans such as Brevican and Versican. We further demonstrate that IL-17A directly activates NF-κB signaling in neural stem cells, leading to sustained inflammatory responses that contribute to these developmental abnormalities. Notably, treatment with the anti-inflammatory agent parthenolide, an inhibitor of NF-κB pathway, reverses IL-17A-induced cortical abnormalities, restoring normal cortical thickness, folding, and neurogenesis. These findings provide valuable insights into how IL-17A disrupts human cortical development during MIA, advancing our understanding of NDD-associated structural cortical alterations.
Project description:Psoriatic arthritis is a seronegative polyarticular form of inflammatory arthritis . Genetic analysis implicates a role for both IL-17/23 axis and CD8+ T cells in disease susceptibility. Using RNA-seq we identified differential gene expression between synovial IL-17A+(IFNy+/-) CD8+ T cells compared to IL-17A-IFNy+ CD8+ T cells and IL-17A+CD4+ T cells from the synovial fluid of psoriatic arthritis patients. We find that IL-17A+CD8+ T cells have a transcriptional overlap with IL-17A+CD4+ T cells. Overall we show these IL-17A+ CD8+ T cells have a polyfunctional, pro-inflammatory capacity and are potentially derived from common precursors, shared with IL-17A-CD8+ T cells.
Project description:Interleukin-17 (IL-17) is a pleiotropic cytokine produced mainly by peripheral Th17 cells. Yet, brain functions of IL-17 derived from central nervous cells remain poorly understood. Here, we find an aberrant IL-17A signaling in the cerebellum of Fmr1-KO mice, a well-established genetic model for autism spectrum disorder (ASD). Cerebellar IL-17A, derived exclusively from microglia, is essential for the regulation of social behaviors by maintaining neuronal excitability and selectively suppressing inhibitory neurotransmission of Purkinje cells (PCs) in the cerebellar Crus I, a brain region critically involved in social cognition. Specific downregulation of IL-17 receptor-mediated signaling in cerebellar PCs recapitulates ASD-like social deficits and repetitive behaviors. Notably, both direct administration of IL-17A and induction of IL-17A release from cerebellar microglia by poly(I:C) effectively restore PC excitability and ameliorate ASD-like symptoms. The findings uncover an indispensable role of microglia-derived IL-17A for cerebellar social processing and suggest potential therapeutic strategies targeting IL-17A signaling for ASD.
Project description:Interleukin-17 (IL-17) is a pleiotropic cytokine produced mainly by peripheral Th17 cells. Yet, brain functions of IL-17 derived from central nervous cells remain poorly understood. Here, we find an aberrant IL-17A signaling in the cerebellum of Fmr1-KO mice, a well-established genetic model for autism spectrum disorder (ASD). Cerebellar IL-17A, derived exclusively from microglia, is essential for the regulation of social behaviors by maintaining neuronal excitability and selectively suppressing inhibitory neurotransmission of Purkinje cells (PCs) in the cerebellar Crus I, a brain region critically involved in social cognition. Specific downregulation of IL-17 receptor-mediated signaling in cerebellar PCs recapitulates ASD-like social deficits and repetitive behaviors. Notably, both direct administration of IL-17A and induction of IL-17A release from cerebellar microglia by poly(I:C) effectively restore PC excitability and ameliorate ASD-like symptoms. The findings uncover an indispensable role of microglia-derived IL-17A for cerebellar social processing and suggest potential therapeutic strategies targeting IL-17A signaling for ASD.
Project description:The goal of this study was to elucidate the effects of inflammation on bone metabolism. As we found IL-17A is induced immediately after bone injury and Il17aâ/â mice showed delayed healing, we analyzed the effects of IL-17A on mesenchymal cells in the repair tissue. Most of the IL-17RA+ cells were PαS cells. We collected these cells and analyzed their response to IL-17A by RNA sequencing. This analysis will provide a mechanistic insight into the mechanism of how IL-17A promote bone formation in the context of bone fracture healing. PαS cells were harvested from the injury tissue of wild-type mice and cultured with or without IL-17A or BMP-2. RNAs were harvested at day 7.
Project description:IL-17A has emerged as a pivotal driver of tissue pathology in many immune-mediated inflammatory diseases. Despite sharing 50% sequence homology and the same signalling pathway, the role of IL-17F remains less clear. RNA sequencing of human IL-17 popualtions isolated using a cytokine capture technique identified clear transcriptional differences in IL-17A and IL-17F producing cells, with IL-17A producing cells showing enrichment for cytokine signaling and IL-17F producing cells showing enrichment for cellular replication.
Project description:IL-17A is a pro-inflammatory cytokine that promotes host defense against infections and contributes to the pathogenesis of chronic inflammatory diseases. Dendritic cells (DC) are antigen-presenting cells responsible for adaptive immune responses. Here, we report that IL-17A induces intense remodeling of lipid metabolism in human monocyte-derived DC, as revealed by microarrays analysis. In particular NR1H3/LXR-a and its target genes were significantly upregulated in response to IL-17A. IL-17A induced accumulation of Oil Red O-positive lipid droplets in DC leading to the generation of lipid-laden DC. A lipidomic study established that all the analyzed lipid species, i.e phospholipids, cholesterol, triglycerides, cholesteryl esters were elevated in IL-17A-treated DC. The increased expression of membrane lipid transporters in IL-17A-treated DC as well as their enhanced ability to uptake the fatty acid Bodipy-FL-C16 suggested that lipid uptake was the main mechanism responsible for lipid accumulation in response to IL-17A. IL-17A-induced lipid laden DC were able to stimulate allogeneic T cell proliferation in vitro as efficiently as untreated DC, indicating that IL-17A-treated DC are potently immunogenic. This study, encompassed in the field of immunometabolism, points out for the first time IL-17A as a modulator of lipid metabolism in DC and provides a rationale to delineate the importance of lipid-laden DC in IL-17A-related inflammatory diseases. We used microarrays analysis to understand the impact of IL-17A on human monocyte-derived human dendritic cells. We found overexpression of many genes involved in lipid metabolism in IL-17A-treated dendritic cells compared to untreated dendritic cells. In particular NR1H3/LXR-a and its target genes were significantly upregulated in response to IL-17A. IL-17A induced accumulation of Oil Red O-positive lipid droplets in DC leading to the generation of lipid-laden DC. A lipidomic study established that all the analyzed lipid species, i.e phospholipids, cholesterol, triglycerides, cholesteryl esters were elevated in IL-17A-treated DC. The increased expression of membrane lipid transporters in IL-17A-treated DC as well as their enhanced ability to uptake the fatty acid Bodipy-FL-C16 suggested that lipid uptake was the main mechanism responsible for lipid accumulation in response to IL-17A. IL-17A-induced lipid laden DC were able to stimulate allogeneic T cell proliferation in vitro as efficiently as untreated DC, indicating that IL-17A-treated DC are potently immunogenic. This study, encompassed in the field of immunometabolism, points out for the first time IL-17A as a modulator of lipid metabolism in DC and provides a rationale to delineate the importance of lipid-laden DC in IL-17A-related inflammatory diseases.