Project description:Invariant natural killer T cells (iNKT) expressing the retinoic acid receptor-related orphan receptor γt (RORγt) and producing IL-17 represent a minor subset of CD1d-restricted iNKT cells (iNKT17) in C57BL/6J (B6) mice. We aimed in this study to define the reasons for their low distribution and the sequence of events accompanying their normal thymic development. We found that RORγt+ iNKT cells have higher proliferation potential and a greater propensity to apoptosis than RORγt- iNKT cells. These cells do not likely reside in the thymus indicating that thymus emigration, and higher apoptosis potential, could contribute to RORγt+ iNKT cell reduced thymic distribution. Ontogeny studies suggest that mature HSAlow RORγt+ iNKT cells might develop through developmental stages defined by a differential expression of CCR6 and CD138 during which RORγt expression and IL-17 production capabilities are progressively acquired. Finally, we found that RORγt+ iNKT cells perceive a strong TCR signal that could contribute to their entry into a specific Th17 like developmental program influencing their survival and migration. Overall, our study proposes a hypothetical thymic developmental sequence for iNKT17 cells, which could be of great use to study molecular mechanisms regulating this developmental program.
Project description:Dysregulated IL-23/IL-17 responses have been linked to psoriatic arthritis and other forms of spondyloarthritides (SpA). RORγt, the key Thelper17 (Th17) cell transcriptional regulator, is also expressed by subsets of innate-like T cells, including invariant natural killer T (iNKT) and γδ-T cells, but how they contribute to disorders such as SpA is still unclear. Here we describe the presence of particular RORγt+T-betloPLZF- iNKT and γδ-hi T cell subsets in healthy peripheral blood. RORγt+ iNKT and γδ-hi T cells showed profound IL-23 mediated Th17-like immune responses and were clearly enriched within inflamed joints of SpA patients where they act as major IL-17 secretors. SpA derived iNKT and γδ-T cells showed a unique Th17 skewed phenotype and gene expression profile. Strikingly, RORγt inhibition blocked γδ17 and iNKT17 cell function while selectively sparing IL-22+ subsets. Overall, these findings highlight a unique diversity of human RORγt+ T cells and underscore the potential of RORγt antagonism to modulate aberrant type 17 responses.
Project description:Group 3 innate lymphoid cells (ILC3) are defined by the expression of RORγt, which is selectively required for their development. The lineage-specified progenitor cells of human ILC3 and their developmental site after birth remain undefined. Here we identified a novel population of human CD34+ hematopoietic progenitor cells (HPC) expressing RORγt and sharing with ILC3 a distinct transcriptional signature. RORγt+ CD34+ HPC were located in tonsils and intestinal lamina propria (LP) and selectively differentiated towards ILC3. Conversely, RORγt- CD34+ HPC displayed commitment potential for both ILC3 and NK cells and the differentiation fate towards these two cell lineages was determined by cytokine and aryl hydrocarbon receptor (AhR) signaling. Thus, we propose that RORγt+ CD34+ cells represent human lineage-specified progenitors of IL-22+ ILC3 and that tonsils as well as intestinal LP might be preferential sites of their differentiation.
Project description:iNKT cells are innate-like lymphocytes that protect against infection, autoimmune disease, and cancer. However, little is known about epigenetic regulation of iNKT cell development. Here, we show that the H3K27me3 histone demethylase UTX is an essential cell-intrinsic factor that controls an iNKT lineage specific gene expression program and epigenetic landscape in a demethylase activity dependent manner. UTX deficient iNKT cells exhibit impaired expression of iNKT signature genes due to a decrease in activation-associated H3K4me3 and an increase in repressive H3K27me3 marks within the promoters that UTX occupies. Notably, we identified JunB as a novel regulator of iNKT development that partners with UTX to establish an iNKT lineage specific gene expression program. Moreover, we demonstrate that UTX-mediated regulation of super-enhancer accessibility is a key mechanism for iNKT lineage commitment. These findings uncover how UTX regulates iNKT cell development through multiple epigenetic mechanisms.
Project description:NKT cells are innate-like lymphocytes that protect against infection, autoimmune disease, and cancer. However, little is known about epigenetic regulation of iNKT cell development. Here, we show that the H3K27me3 histone demethylase UTX is an essential cell-intrinsic factor that controls an iNKT lineage specific gene expression program and epigenetic landscape in a demethylase activity dependent manner. UTX-deficient iNKT cells exhibit impaired expression of iNKT signature genes due to a decrease in activation-associated H3K4me3 and an increase in repressive H3K27me3 marks within the promoters that UTX occupies. Notably, we identified JunB as a novel regulator of iNKT development that partners with UTX to establish an iNKT lineage specific gene expression program. Moreover, we demonstrate that UTX-mediated regulation of super-enhancer accessibility is a key mechanism for iNKT lineage commitment. These findings uncover how UTX regulates iNKT cell development through multiple epigenetic mechanisms.
Project description:We confirm previous findings that adipose iNKT cells are transcriptionally distinct from canoncial splenic iNKT cells and we demonstrate that the adipose iNKT cell population is hetergeneous, containing two major functional subsets which can be segregated by expression of the surface marker NK1.1 (Klrb1c). Both of these adipose iNKT cell subsets play a role in the regulation of adipose tissue tissue homeostasis, including NK1.1+ iNKT cells, which produce IFNγ and induce adipose NK cell-mediated killing of adipose tissue macrophages.
Project description:Development of T cells is controlled by the signal strength of the TCR. The scaffold protein Kinase D-interacting substrate of 220 kDa (Kidins220) binds to the TCR; however, its role in T cell development was unknown. Here, we show that T cell-specific Kidins220 knock-out (T-KO) mice have strongly reduced invariant natural killer T (iNKT) cell numbers and modest decreases in conventional T cells. Enhanced apoptosis due to increased TCR signaling in T-KO iNKT thymocytes of developmental stage 2 and 3 shows that Kidins220 downregulates TCR signaling at these stages. scRNAseq indicated that the transcription factor Aiolos is downregulated in Kidins220-deficient iNKT cells. Analysis of an Aiolos KO demonstrated that Aiolos is a downstream effector of Kidins220 during iNKT cell development. In the periphery, T-KO iNKT cells show reduced TCR signaling upon stimulation with α-galactosylceramide, suggesting that Kidins220 promotes TCR signaling in peripheral iNKT cells. Thus, Kidins220 reduces or promotes signaling dependent on the iNKT cell developmental stage.
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:We show that iNKT cells undergo rapid and extensive transcriptional remodeling after activation with the lipid antigen αGalactosylceramide (αGalCer). A common transcriptional framework underpins the activation of heterogeneous iNKT cell populations, including NKT1, NKT2 and NKT17 cells. We show that regulatory iNKT cell populations, including iNKT cells from epididymal adipose tissue, undergo blunted activation and show reduced transcriptional remodeling after αGalCer. We find that regulatory iNKT cell populations are enriched for memory-like KLRG1+ and cMAF+ iNKT subsets, and express gene signatures associated with adaptive Tr1 cells. IL-10 producing NKT10 cells express cMAF, and show enrichment for a cMAF-associated gene network. We also show that NKT10 cells are also phenotypically similar to adaptive Tr1 cells and NKTFH cells.