Project description:Interleukin-23 (IL-23) is a pro-inflammatory cytokine required for the pathogenicity of T helper 17 (Th17) cells but the molecular mechanisms governing this process remain unclear. We identified the transcription factor Blimp-1 (Prdm1) as a key IL-23-induced factor that drove the inflammatory function of Th17 cells. In contrast to thymic deletion of Blimp-1, which causes T cell development defects and spontaneous autoimmunity, peripheral deletion of this transcription factor resulted in reduced Th17 activation and reduced severity of autoimmune encephalomyelitis. Furthermore, genome wide occupancy and overexpression studies in Th17 cells revealed that Blimp-1 co-localized with transcription factors RORγt, STAT-3 and p300 at the Il23r, Il17a/f and Csf2 cytokine loci to enhance their expression. Blimp-1 also directly bound to and repressed cytokine loci Il2 and Bcl6. Taken together, our results demonstrate that Blimp-1 is an essential transcription factor downstream of IL-23 that acts in concert with RORγt to activate the Th17 inflammatory program. Genome-wide binding analysis of Blimp1 from in vitro generated T effector and regulatory cells
Project description:Interleukin-23 (IL-23) is a pro-inflammatory cytokine required for the pathogenicity of T helper 17 (Th17) cells but the molecular mechanisms governing this process remain unclear. We identified the transcription factor Blimp-1 (Prdm1) as a key IL-23-induced factor that drove the inflammatory function of Th17 cells. In contrast to thymic deletion of Blimp-1, which causes T cell development defects and spontaneous autoimmunity, peripheral deletion of this transcription factor resulted in reduced Th17 activation and reduced severity of autoimmune encephalomyelitis. Furthermore, genome wide occupancy and overexpression studies in Th17 cells revealed that Blimp-1 co-localized with transcription factors RORγt, STAT-3 and p300 at the Il23r, Il17a/f and Csf2 cytokine loci to enhance their expression. Blimp-1 also directly bound to and repressed cytokine loci Il2 and Bcl6. Taken together, our results demonstrate that Blimp-1 is an essential transcription factor downstream of IL-23 that acts in concert with RORγt to activate the Th17 inflammatory program.
Project description:Interleukin-17 (IL-17)-secreting T helper 17 cells (Th17) are a recently identified CD4+ T helper subset that has been implicated in various inflammatory and autoimmune diseases. The issue of whether interleukin-17A (IL-17) contributes to hyperlipidemia-induced aortic endothelial cell activation remained unknown. Here, we reported that IL-17 contributes to hyperlipidemia-induced modulation of vascular cell gene expression during early atherosclerosis in vivo. Our results has shed lights onto the role of IL-17 on EC biology and has provided important insights for future development of novel therapeutics for early intervention of cardiovascular diseases and other inflammatory diseases.
Project description:CD4+ T cells that selectively produce interleukin (IL)-17, are critical for host defense and autoimmunity1-4. Crucial for T helper17 (Th17) cells in vivo5,6, IL-23 has been thought to be incapable of driving initial differentiation. Rather, IL-6 and transforming growth factor (TGF)-β1 have been argued to be the factors responsible for initiating specification7-10. Herein, we show that Th17 differentiation occurs in the absence of TGF-β signaling. Neither IL-6 nor IL-23 alone efficiently generated Th17 cells; however, these cytokines in combination with IL-1β effectively induced IL-17 production in naïve precursors, independently of TGF-β. Epigenetic modification of the Il17a/Il17f and Rorc promoters proceeded without TGF-β1, allowing the generation of cells that co-expressed Rorγt and T-bet. T-bet+Rorγt+ Th17 cells are generated in vivo during experimental allergic encephalomyelitis (EAE), and adoptively transferred Th17 cells generated with IL-23 in the absence of TGF-β1 were more pathogenic in this experimental disease. These data suggest a new model for Th17 differentiation. Consistent with genetic data linking the IL23R with autoimmunity, our findings re-emphasize the role of IL-23 and therefore have important implications for the development of new therapies. Mouse T helper 17 cell differentiation with or without TGFB
Project description:Chronic autoimmune skin disease characterized by epidermal proliferation with hyper- and para-keratosis. The aberrant background immune response involves helper T-lymphocyte types 1 and 17 and their respective secreted cytokines tumor necrosis factor alpha (TNF) and interleukin 17 (IL-17). These pro-inflammatory cytokines stimulate the activation of keratinocytes, resulting in the release of acute phase cytokines, followed by chronic phase cytokines thus promotes induced hyperplasia of keratinocyte. The pro-differentiative action of fisetin on dual cytokine-induced abnormally proliferating keratinocyte revealed downregulation of psoriasis-associated genes and activation of autophagic genes, as well as normalization of genes involved in keratinocyte terminal differentiation. These result supports the effect of fisetin on improving psoriasis like inflammatory flareups in cultured keratinocyte in vitro.
Project description:CD4+ T cells that selectively produce interleukin (IL)-17, are critical for host defense and autoimmunity. Crucial for T helper17 (Th17) cells in vivo, IL-23 has been thought to be incapable of driving initial differentiation. Rather, IL-6 and transforming growth factor (TGF)-β1 have been argued to be the factors responsible for initiating specification. Herein, we show that Th17 differentiation occurs in the absence of TGF-β signaling. Neither IL-6 nor IL-23 alone efficiently generated Th17 cells; however, these cytokines in combination with IL-1β effectively induced IL-17 production in naïve precursors, independently of TGF-β. Epigenetic modification of the Il17a/Il17f and Rorc promoters proceeded without TGF-β1, allowing the generation of cells that co-expressed Rorγt and T-bet. T-bet+Rorγt+ Th17 cells are generated in vivo during experimental allergic encephalomyelitis (EAE), and adoptively transferred Th17 cells generated with IL-23 in the absence of TGF-β1 were more pathogenic in this experimental disease. These data suggest a new model for Th17 differentiation. Consistent with genetic data linking the IL23R with autoimmunity, our findings re-emphasize the role of IL-23 and therefore have important implications for the development of new therapies. Examination of Stat3 binding and H3K4me and H3Ac in helper T cells.
Project description:Regulatory T (Treg) cells are required for peripheral tolerance. Recent evidence indicates that Treg cells can adopt specialized differentiation programs in the periphery that are controlled by transcription factors usually associated with T helper differentiation. We demonstrate that expression of the transcription factor Blimp1 defines a population of Treg cells that localize predominantly to mucosal sites and produces IL-10. Blimp1 is required for IL-10 production by these cells and for their tissue homeostasis. A list of differentially expressed genes were identified from this whole-genome expression profiling experiment. Mouse Blimp1 +/gfp and Blimp1 gfp/gfp regulatory T cells were analyzed. Three replicates each.
Project description:Cytokines are highly pleiotropic ligands that critically contribute to a balanced immune response. We have an incomplete understanding of how cytokines elicit their functional pleiotropy, which has limited their therapeutic efficacy. Here, using Interleukin-6 (IL-6) as a model system, we have performed detailed phosphoproteomic and transcriptomic studies in human CD4 + T helper (Th)-1 cells to address the molecular bases defining cytokine functional pleiotropy. We have identified cyclin dependent kinase (CDK)8 as a new negative regulator of transcriptional activities of signal transducer and activator of transcription (STAT)3. We found that CDK8 is a major regulator of the IL-6 phosphoproteome and interacts with STAT3 in the nucleus upon IL-6 stimulation. Inhibition of CDK8 activity, using specific small molecules inhibitors, reduced the IL-6-induced phosphoproteome by 23% in Th-1 cells, including STAT3 S727 phosphorylation. STAT3 binding to target DNA sites in the genome was increased upon CDK8 inhibition, which resulted in a concomitant increase in STAT3 mediated transcriptional activity. Importantly, inhibition of CDK8 activity under Th-17 polarizing conditions resulted in an enhancement of Th-17 differentiation. Our results support a model where CDK8 regulates STAT3 transcriptional processivity via modulation of its gene loci resident time, critically contributing to diversification of IL-6 responses.
Project description:During the immune response, CD4+ T cells differentiate into distinct effector subtypes, including follicular helper T (Tfh) cells that help B cells, and into memory cells. Tfh and memory cells are required for long-term immunity; both depend on the transcription factor Bcl6, raising the question of whether they differentiate through similar mechanisms. Here, using notably single-cell RNA and ATAC sequencing, we show that virus-responding CD4+ T cells lacking both Bcl6 and Blimp1 can differentiate into cells with transcriptomic, chromatin accessibility and function attributes of memory cells, but not of Tfh cells. Thus, Bcl6 promotes memory cell differentiation primarily through its repression of Blimp1. These findings demonstrate that distinct mechanisms underpin the differentiation of memory and Tfh CD4+ cell and define the Bcl6-Blimp1 axis as a potential target for promoting long-term memory T cell differentiation.
Project description:During the immune response, CD4+ T cells differentiate into distinct effector subtypes, including follicular helper T (Tfh) cells that help B cells, and into memory cells. Tfh and memory cells are required for long-term immunity; both depend on the transcription factor Bcl6, raising the question of whether they differentiate through similar mechanisms. Here, using notably single-cell RNA and ATAC sequencing, we show that virus-responding CD4+ T cells lacking both Bcl6 and Blimp1 can differentiate into cells with transcriptomic, chromatin accessibility and function attributes of memory cells, but not of Tfh cells. Thus, Bcl6 promotes memory cell differentiation primarily through its repression of Blimp1. These findings demonstrate that distinct mechanisms underpin the differentiation of memory and Tfh CD4+ cell and define the Bcl6-Blimp1 axis as a potential target for promoting long-term memory T cell differentiation.