Project description:Immunity to fungal infections is mediated by cells of the innate and adaptive immune system. Activation of immune cells requires Ca2+ influx through the Ca2+ channel ORAI1, which is activated by stromal interaction molecule 1 (STIM1). Th17 cells are essential for immunity to C. albicans infection and require Ca2+ influx for expression of IL-17A and other Th17 cytokines. In mice, deletion of STIM1 and thus Ca2+ influx in all immune cells enhanced susceptibility to mucosal C. albicans infection, whereas T cell-specific deletion of STIM1 impaired immunity to systemic C. albicans infection. STIM1 deletion in CD4 T cells had different effects on gene expression programs in pathogenic (proinflammatory) and non-pathogenic Th17 cells. STIM1 deletion in non-pathogenic Th17 cells, which are required for antifungal immunity, compromised the expression of genes in several metabolic pathways including Foxo and HIF-1a signaling as well as the TCA cycle and oxidative phosphorylation (OXPHOS). Consequently, STIM1 deficient non-pathogenic Th17 cells had impaired glycolysis and mitochondrial respiration. By contrast, STIM1 deletion in pathogenic Th17 cells showed only attenuated mitochondrial function but normal glycolysis.
Project description:Pathogenic Th17 cells play an important role in many autoimmune and inflammatory diseases. Their function is dependent on signaling through the T cell receptor (TCR) and cytokines that activate the transcription factor signal transducer and activator of transcription 3 (STAT3). TCR engagement activates stromal interaction molecule 1 (STIM1) and calcium (Ca2+) influx through the Ca2+ release-activated Ca2+ (CRAC) channel. We here show that deletion of STIM1 and Ca2+ influx in T cells expressing a hyperactive form of STAT3 (STAT3C) attenuates pathogenic Th17 cell function and multiorgan inflammation associated with STAT3C expression. Deletion of STIM1 in pathogenic Th17 cells impairs the expression of nuclear encoded mitochondrial electron transport chain genes and oxidative phosphorylation (OXPHOS) but enhances reactive oxygen species (ROS) production. Deletion of STIM1 or inhibition of OXPHOS is associated with impaired Th17 cell function and a non-pathogenic Th17 gene expression signature. Our findings establish STIM1 and Ca2+ signals as a critical regulator of OXPHOS and oxidative stress in pathogenic Th17 cells and multiorgan inflammation.
Project description:Influence of STIM1 on the transcriptome of CD4+ T cell subsets STIM1 is critical for the regulation of the intracellular Ca2+ homeostasis in CD4+ T cell. Loss of function mutations in STIM1 in patients result in severe immuno deficiency and recurrent infections. Using conditional knock out mice for STIM1, we investigated the role of STIM1 in T cells during chronic infections by in-vivo and in-vitro experiments. We found that STIM1 is required for T cell-mediated immunity to chronic infection with Mycobacterium tuberculosis (Mtb) as STIM1-deficient mice succumb to infection faster than littermate controls, have increased mycobacterial burdens and severe pulmonary infiltration with myeloid and lymphoid cells .Using the Affymetrix Mouse Exon 1.0 platform, we analyzed the influence of STIM1 expression on the transcriptom of CD4+T cells in-vitro. We found that STIM1 is required for the regulation of apoptosis related genes after TCR stimulation as well as for the induction of a transcriptonal program that polarizes naive CD4+ T cells into inducible CD4+ T regulatory cells (iTreg). Together with our in-vivo findings, these experiments reveal that STIM1 is essential for immune regulation to prevent an injurious inflammatory response during chronic infection.
Project description:TGF-beta3 produced by developing Th17 cells induces highly pathogenic T cells that are functionally and molecularly distinct from TGF-beta1-induced Th17 cells. The microarray data represent a distinct molecular signature for pathogenic versus non-pathogenic Th17 cells.
Project description:Calcineurin/NFAT/IL-2 signaling pathway is activated in dendritic cells (DC) upon encounter of β glucan, the main component of the fungal cell wall, raising the question about the role of NFAT-regulated genes in DC biology in vivo. To directly assess the function of IL-2 secreted by DC, we analyzed mice lacking of IL-2 in the DC lineage, CD4-expressing cells and with complete deletion of IL-2 in the germ line in a mouse model of pulmonary fungal infection. Here we found that specifically the loss of IL-2 in DC resulted in increased mice mortality upon the fungus Aspergillus fumigatus challenge and expansion of Th17 cells in the lung. We demonstrated that only CD103+DC were able to release IL-2 in acute phase of pulmonary Aspergillosis through the Ca2+-Calcineurin-NFAT signaling. We also found that NFAT mediates IL-23 transcription in lung DC, where IL-2 results essential in restraining the priming of a pathogenic infiltrating IL-17+Sca1+CD90+CD4+ cell with stem cell like properties. Thus, IL-2 and IL-23 secreted by DC in the lung have an antagonistic relationship on the Th17 differentiation program with IL-2 inducing T cell differentiation and IL-23 inducing a stem cell like molecular signature to Th17 cells upon Aspergillus challenge. DC-Il2-/- then confer the Th17 stemness, releasing IL-23 in response to the fungus contributing to the development of a Th17 cell effector population, particularly pathogenic in infection. D1 cells with no treatment, or treatment with different fungal types or antigens at 1, 4 and 6 hours, in triplicate, with the 3 untreated samples at 1hr also including techincal repeats
Project description:TGF-beta3 produced by developing Th17 cells induces highly pathogenic T cells that are functionally and molecularly distinct from TGF-beta1-induced Th17 cells. The microarray data represent a distinct molecular signature for pathogenic versus non-pathogenic Th17 cells. Total of seven groups with two to four samples per group from two independent experiments. The no cytokines group (Th0) was used as a control to normalize the data. 7 groups: B6: (IL-1beta, IL-6) B623: (IL-1beta, IL-6, IL-23) T16: (TGF-beta1, IL-6) T1623: (TGF-beta1, IL-6, IL-23) T36: (TGF-beta3, IL-6) T3623: (TGF-beta3, IL-6, IL-23) NOCYTO: no cytokines
Project description:CD4+ T cells differentiate into phenotypically distinct T-helper cells upon antigenic stimulation. Regulation of plasticity between these CD4+ T-cell lineages is critical for immune homeostasis and prevention of autoimmune diseases. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stability using T helper 1 (Th1) cells, traditionally considered the most phenotypically stable Th subset. We found that RA, through its receptor RARa, sustains stable expression of Th1 lineage specifying genes as well as repressing genes that instruct Th17 cell fate. RA signaling is essential for limiting Th1 cell conversion into Th17 effectors and for preventing pathogenic Th17 responses in vivo. Our studies identify RA-RARa as a key component of the regulatory network governing Th1 cell fate and define a new paradigm for the development of pathogenic Th17 cells. These findings have important implications for autoimmune diseases in which dysregulated Th1-Th17 responses are observed. IFN-gamma+ Th1 cells from IFNgeYFP reporter mouse; comparing dnRARa to WT
Project description:CD4+ T cells differentiate into phenotypically distinct T-helper cells upon antigenic stimulation. Regulation of plasticity between these CD4+ T-cell lineages is critical for immune homeostasis and prevention of autoimmune diseases. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stability using T helper 1 (Th1) cells, traditionally considered the most phenotypically stable Th subset. We found that RA, through its receptor RARa, sustains stable expression of Th1 lineage specifying genes as well as repressing genes that instruct Th17 cell fate. RA signaling is essential for limiting Th1 cell conversion into Th17 effectors and for preventing pathogenic Th17 responses in vivo. Our studies identify RA-RARa as a key component of the regulatory network governing Th1 cell fate and define a new paradigm for the development of pathogenic Th17 cells. These findings have important implications for autoimmune diseases in which dysregulated Th1-Th17 responses are observed. Identification of RARa binding in wild-type Th1 cells and mapping of enhancers using chromatin IP against p300, H3k4me1, H3k4me3, and H3k27ac in wild-type and dnRara Th1 cells.
Project description:Calcineurin/NFAT/IL-2 signaling pathway is activated in dendritic cells (DC) upon encounter of β glucan, the main component of the fungal cell wall, raising the question about the role of NFAT-regulated genes in DC biology in vivo. To directly assess the function of IL-2 secreted by DC, we analyzed mice lacking of IL-2 in the DC lineage, CD4-expressing cells and with complete deletion of IL-2 in the germ line in a mouse model of pulmonary fungal infection. Here we found that specifically the loss of IL-2 in DC resulted in increased mice mortality upon the fungus Aspergillus fumigatus challenge and expansion of Th17 cells in the lung. We demonstrated that only CD103+DC were able to release IL-2 in acute phase of pulmonary Aspergillosis through the Ca2+-Calcineurin-NFAT signaling. We also found that NFAT mediates IL-23 transcription in lung DC, where IL-2 results essential in restraining the priming of a pathogenic infiltrating IL-17+Sca1+CD90+CD4+ cell with stem cell like properties. Thus, IL-2 and IL-23 secreted by DC in the lung have an antagonistic relationship on the Th17 differentiation program with IL-2 inducing T cell differentiation and IL-23 inducing a stem cell like molecular signature to Th17 cells upon Aspergillus challenge. DC-Il2-/- then confer the Th17 stemness, releasing IL-23 in response to the fungus contributing to the development of a Th17 cell effector population, particularly pathogenic in infection.