Project description:Interleukin 23 (IL-23) triggers pathogenic features in pro-inflammatory, IL-17-secreting T cells (Th17 and Tγδ17) that play a key role in the development of inflammatory diseases. However, the IL-23 signaling cascade remains largely undefined. Here we used quantitative phosphoproteomics to characterize IL-23 signaling in primary murine Th17 cells. We quantified 6,888 phosphorylation sites in Th17 cells, and found 168 phosphorylations regulated upom IL-23 stimulation. IL-23 increased the phosphorylation of the myosin regulatory light chain (RLC), an actomyosin contractibility marker, in Th17 and Tγδ cells. IL-23-induced RLC phosphorylation required JAK2 and ROCK catalytic activity, and the study of the IL-23/ROCK axis revealed an unexpected role of IL-23 in the migration of Tγδ17 and Th17 cells. Moreover, pharmacological inhibition of ROCK reduced Tγδ17 recruitment to inflamed skin upon challenge with inflammatory agent Imiquimod. This work: i) provides new insights into phosphorylation networks that control Th17 cells, ii) widely expands the current knowledge on IL-23 signaling, and iii) contributes to the increasing list of immune cells subsets characterized by global phosphoproteomic approaches.
Project description:Whole cell extracts from mouse Th17 cells treated with activin A were profiled with extensive fractionation and bottom-up proteomics
Project description:Transcriptional profiling of mouse Th17 cells comparing WT Th17 cells with Pten-deficient Th17 cells. Naïve CD4 T cells from each mice were cultured Th17 polarizing condition for 3 days. Goal was to determine the effects of Pten on global gene expression.
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:The early stages of human Th17 Cell differentiation were studied using label free proteomics to compare Th17 polarized CD4+ human T cells at 24 h and 72 h with activated cells (72 and 24 h) and Thp cells.
Project description:RORγt is a transcription factor required for T helper 17 (Th17) cell development. We identified three RORγt-specific inhibitors that suppress Th17 cell responses including Th17 cell-mediated autoimmune disease. We systemically characterized RORγt binding data in the presence and absence of drug with corresponding whole-transcriptome sequencing for wild-type and RORγt-deficient cells. RORγt is central in a densely interconnected regulatory network, acting both as a direct activator of genes important for Th17 cell differentiation and as a direct repressor of genes from other T-cell lineages. The three inhibitors identified here reversed both of these modes of action, but to varying extents and through distinct mechanisms. Whereas one inhibitor displaced RORγt from its target-loci, the two more potent inhibitors affected transcription predominantly without removing DNA-binding. Our work illustrates the power of a system-scale analysis of transcriptional regulation to characterize potential therapeutic compounds that inhibit pathogenic Th17 cells and suppress autoimmunity. DNA binding of RORγt in WT Th17 cells and under chemical perturbations of RORγt; Additional data is included for epitope-tagged exogenous RORγt in EL4 cells (a murine lymphoma cell line)
Project description:The differentiation of Th17 cells is controlled by a complex network of transcription factors (TFs), including FOS and JUN proteins of the AP-1 family. The FOS-like proteins, FOSL1 and FOSL2 have recently been reported to control Th17 responses. The molecular mechanisms dictating their roles, however, are unclear. Moreover, although the functions of AP-1 TFs are largely governed by their protein-protein interactions, these are also poorly characterized in this milieu. Using affinity purification in combination with mass-spectrometry we established the first interactomes of FOSL1 and FOSL2 in human Th17 cells. In addition to their known interactions with JUN proteins, our analysis identified several novel binding partners of FOSL factors. Gene ontology analysis revealed RNA binding was enriched as the major functionality for FOSL1 and FOSL2 associated proteins, thereby suggesting possible mechanistic links that have not been studied before. Intriguingly, 29 interactors were found to be shared between FOSL1 and FOSL2, which included crucial regulators of Th17-fate. These findings, including unique and shared interactions, were validated using parallel reaction monitoring targeted mass-spectrometry (PRM-MS), with additional measurements with other laboratory methods. Overall, this study provides key insights into interaction-based signalling mechanisms of FOSL1 and FOSL2, which potentially control Th17 cell-development and associated pathologies.