Project description:RORgt is known to instruct the differentiation of Th17 cells that mediate the pathogenesis of autoimmune diseases. However, it remains unknown whether RORgt plays a distinct role in the differentiation and effector function of Th17 cells. Here we show that mutation of RORgt lysine 256, a ubiquitination site, to arginine (K256R) separates the RORgt role in these two functions. Preventing ubiquitination at K256 via arginine substitution does not affect RORgt-dependent thymocyte development and Th17 differentiation in vitro and in vivo, however, greatly impaired the pathogenesis of Th17 cell-mediated experimental autoimmune encephalomyelitis (EAE). Mechanistically, K256R mutation impairs RORgt to bind to and activate Runx1 expression critical for Th17-mediated EAE. Thus, RORgt regulates the effector function of Th17 cells in addition to Th17 differentiation. This work informs the development of RORgt-based therapies that specifically target the effector function of Th17 cells responsible for autoimmunity.
Project description:Interleukin 17 (IL-17) producing T helper 17 (Th17) cells are critical drivers of pathogenesis in a variety of autoimmune and inflammatory diseases. Strategies to mitigate excessive Th17 response thus remain an attractive target for immunotherapies. Here we report that Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) regulates IL-17 production by Th17 cells in human and mouse. Using CIP2A knock-out (KO) mice and siRNA-mediated CIP2A silencing in human primary CD4+ T cells, we demonstrated that CIP2A silencing results in a significant increase in IL-17 production. Interestingly, CIP2A deficient Th17 cells were characterized by increased strength and duration of STAT3 (Y705) phosphorylation. Genome-wide gene expression profile as well as the p-STAT3 (Y705) interactome of CIP2A deficient Th17 cells identified that CIP2A regulates the strength of the interaction between Acylglycerol kinase (AGK) and STAT3, and thereby, modulates STAT3 phosphorylation as well as expression of IL-17 in Th17 cells. Our results uncover the physiological function of CIP2A in Th17 cells and provides new opportunities for therapeutic intervention in Th17 cell mediated diseases.
Project description:Th17 cells are a helper cell subset of pro-inflammatory T cells, which have diverse functions ranging from neutrophilic-inflammatory responses against pathogens to driving a number of autoimmune diseases. Accumulating evidence indicates that specific cellular lipid metabolic pathways that include fatty acid or cholesterol play an essential role in regulating the differentiation and function of Th17 cells. However, what molecular mechanisms link lipid metabolism and RORgt function during Th17-cell differentiation? By using a combination of a CRISPR- based screening system and a global lipidome analysis, we addressed this question in an effort to identify a specific lipid metabolite that is essential for RORgt-mediated Th17-cell differentiation. We found five lipid enzymes that elicit RORgt activity and constitute a core molecular signature of Th17 cells. Furthermore, although Th17 cells treated with TOFA, which is a ACC1 inhibitor, showed decreased mRNA expression of Th17 specific gene and chromatin accessibility at Th17 cell specific gene loci, we also found that extrinsic supplementation of LPE (1-18:1) restored the phenotype of ACC1-inhibited Th17 cells. Taken together, these series of results indicated that LPE (1-18:1) synthesized from the five lipid metabolic enzymes was required for RORgt to function appropriately in Th17-cell differentiation.
Project description:T helper 17 (Th17) cells produce interleukin-17 (IL-17) cytokines and drive inflammatory responses in autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. The differentiation of Th17 cells is dependent on the retinoic acid receptor-related orphan nuclear receptor RORgt. Here we identify REV-ERBa (encoded by Nr1d1), a member of the nuclear hormone receptor family (NHR), as a transcriptional repressor that antagonizes RORgt function in Th17 cells. REV-ERBa binds to ROR response elements (RORE) in Th17 cells and inhibits the expression of RORgt-dependent genes such as Il17a and Il17f. Furthermore, elevated REV-ERBa expression or treatment with a synthetic REV-ERB agonist significantly delays the onset and impedes the progression of experimental autoimmune encephalomyelitis (EAE), a Th17 cell-mediated autoimmune disease. These results suggest that modulating REV-ERB activity may hold therapeutic potential for treatment of Th17 cell-mediated autoimmune diseases.
Project description:STAT3 is an immidiate regulator of Th17 differentiation. STAT3 difieciency downmodulate Th17 specific genes and Th17 responses. Therefore, we intend to identify genome wide targets of STAT3. We used microarrays to profile gene expression of STAT3 regulated genes during Th17 polarization. Total RNA was extracted from non-targeting and STAT3 siRNA treated Thp, Th0 and Th17 cell samples from different time points. Total RNA subjected to poly-A selection and hybridization on Affymetrix microarrays.
Project description:Th17-related genes increased in T cells from PINK1-deficient mice. Th17 and Treg cells were increased and decreased in PINK1-deficient cells, respectively, and phosphorylation of signal transducer and activator of transcription 3 (STAT3) was increased in PINK1-deficient cells.
Project description:STAT3 is an immidiate regulator of Th17 differentiation. STAT3 difieciency downmodulate Th17 specific genes and Th17 responses. Therefore, we intend to identify genome wide targets of STAT3. We used microarrays to profile gene expression of STAT3 regulated genes during Th17 polarization.
Project description:Interleukin 2 (IL-2), a cytokine linked to human autoimmune diseases, limits IL-17 production. We show that deletion of Stat3 in T cells abrogates IL-17 production and attenuates autoimmunity associated with IL-2 deficiency. While STAT3 induces IL-17 and RORγt and inhibits Foxp3, IL-2 inhibited IL-17 independently of Foxp3 and RORγt. We found that STAT3 and STAT5 bound to multiple common sites across the Il17 genetic locus. The induction of STAT5 binding by IL-2 was associated with a reduction in STAT3 binding at these sites and the inhibition of associated active epigenetic marks. Titrating the relative activation of STAT3 and STAT5 modulated TH17 cell specification. Thus, the balance rather than the absolute magnitude of these signals determines the propensity of cells to make a key inflammatory cytokine. The genome-wide binding of STAT3 and STAT5 under Th17 conditions was investigated by CHIP-seq.
Project description:Interleukin 2 (IL-2), a cytokine linked to human autoimmune diseases, limits IL-17 production. We show that deletion of Stat3 in T cells abrogates IL-17 production and attenuates autoimmunity associated with IL-2 deficiency. While STAT3 induces IL-17 and ROR?t and inhibits Foxp3, IL-2 inhibited IL-17 independently of Foxp3 and ROR?t. We found that STAT3 and STAT5 bound to multiple common sites across the Il17 genetic locus. The induction of STAT5 binding by IL-2 was associated with a reduction in STAT3 binding at these sites and the inhibition of associated active epigenetic marks. Titrating the relative activation of STAT3 and STAT5 modulated TH17 cell specification. Thus, the balance rather than the absolute magnitude of these signals determines the propensity of cells to make a key inflammatory cytokine. The roles of STAT3 and STAT5 in regulation of gene expression under Th17 differentiation was investigated. Affymetrix Mouse Genome 430 2.0 Arrays were used to evaluate global gene expression.