Project description:Dysregulated Th17 cell responses underlie multiple inflammatory and autoimmune diseases, including autoimmune uveitis and its animal model, EAU. However, clinical trials targeting IL-17A in uveitis were not successful. Here, we found that Th17 cells were regulated by their own signature cytokine, IL-17A. Loss of IL-17A in autopathogenic Th17 cells did not reduce their pathogenicity and instead elevated their expression of the Th17 cell cytokines GM-CSF and IL-17F. Mechanistic in vitro studies revealed a Th17 cell-intrinsic autocrine loop triggered by binding of IL-17A to its receptor, leading to activation of transcription factor NFκB and induction of IL 24, which repressed the Th17 cytokine program. In vivo, IL-24 treatment ameliorated Th17-induced EAU, whereas silencing of IL-24 in Th17 cells enhanced disease. This regulatory pathway also operated in human Th17 cells. Thus, IL-17A limits pathogenicity of Th17 cells by inducing IL-24. These findings may explain the disappointing therapeutic effect in targeting IL-17A in uveitis.
Project description:Extensive cellular heterogeneity exists within specific immune-cell subtypes classified as a single lineage, but its molecular underpinnings are rarely characterized at a genomic scale. Here, we use single-cell RNA-seq to investigate the molecular mechanisms governing heterogeneity and pathogenicity of Th17 cells isolated from the central nervous system (CNS) and lymph nodes (LN) at the peak of autoimmune encephalomyelitis (EAE) or polarized in vitro under either pathogenic or non-pathogenic differentiation conditions. Computational analysis reveals a spectrum of cellular states in vivo, including a self-renewal state, Th1-like effector/memory states and a dysfunctional/senescent state. Relating these states to in vitro differentiated Th17 cells, unveils genes governing pathogenicity and disease susceptibility. Using knockout mice, we validate four novel genes: Gpr65, Plzp, Toso and Cd5l (in a companion paper). Cellular heterogeneity thus informs Th17 function in autoimmunity, and can identify targets for selective suppression of pathogenic Th17 cells while sparing non-pathogenic tissue-protective ones. Single-cell transcriptional profiling of Th17 cells, differentiated in vitro for 48h
Project description:Extensive cellular heterogeneity exists within specific immune-cell subtypes classified as a single lineage, but its molecular underpinnings are rarely characterized at a genomic scale. Here, we use single-cell RNA-seq to investigate the molecular mechanisms governing heterogeneity and pathogenicity of Th17 cells isolated from the central nervous system (CNS) and lymph nodes (LN) at the peak of autoimmune encephalomyelitis (EAE) or polarized in vitro under either pathogenic or non-pathogenic differentiation conditions. Computational analysis reveals a spectrum of cellular states in vivo, including a self-renewal state, Th1-like effector/memory states and a dysfunctional/senescent state. Relating these states to in vitro differentiated Th17 cells, unveils genes governing pathogenicity and disease susceptibility. Using knockout mice, we validate four novel genes: Gpr65, Plzp, Toso and Cd5l (in a companion paper). Cellular heterogeneity thus informs Th17 function in autoimmunity, and can identify targets for selective suppression of pathogenic Th17 cells while sparing non-pathogenic tissue-protective ones. Single-cell transcriptional profiling of Th17 cells, differentiated in vitro for 48h
Project description:Extensive cellular heterogeneity exists within specific immune-cell subtypes classified as a single lineage, but its molecular underpinnings are rarely characterized at a genomic scale. Here, we use single-cell RNA-seq to investigate the molecular mechanisms governing heterogeneity and pathogenicity of Th17 cells isolated from the central nervous system (CNS) and lymph nodes (LN) at the peak of autoimmune encephalomyelitis (EAE) or polarized in vitro under either pathogenic or non-pathogenic differentiation conditions. Computational analysis reveals a spectrum of cellular states in vivo, including a self-renewal state, Th1-like effector/memory states and a dysfunctional/senescent state. Relating these states to in vitro differentiated Th17 cells, unveils genes governing pathogenicity and disease susceptibility. Using knockout mice, we validate four novel genes: Gpr65, Plzp, Toso and Cd5l (in a companion paper). Cellular heterogeneity thus informs Th17 function in autoimmunity, and can identify targets for selective suppression of pathogenic Th17 cells while sparing non-pathogenic tissue-protective ones. Single-cell transcriptional profiling of Th17 cells, differentiated in vitro for 48h
Project description:Th17 cells secrete IL-17A, IL-17F, IL-21, and IL-22 cytokines that are critical in mediating inflammation and protecting the host from microorganisms infection. The basic leucine zipper transcription factor ATF-like (Batf) contributes to the transcriptional programming of multiple effector T cells, and is required for Th17 cell development. Here, we have interrogated mechanisms by which Batf promotes and stabilizes Th17 cell phenotype. We have shown that in vitro differentiated Th17 cells have increased expression of Th1 and Treg signature genes in the absence of Batf. In addition, Citrobacter rodentium infected Batf-deficient (Batf KO) mice fail to clear the infection, and that is correlated with diminished IL-17A and IL-22 cytokine production and increased Foxp3 and Ifng expression compared to WT mice. We find that Batf sustains Th17 phenotype in long-term culture conditions by suppressing Th1- and Treg-specific gene expression. Mechanistically, we reveal that Batf negatively regulates IL-2-STAT5 signaling and modulates STAT5 binding at the Ifng and Foxp3 gene loci thus suppressing Th1-Treg phenotype in Th17 cell development. Inhibition of STAT5 DNA binding activity in Batf KO Th17 cells was able to repress Ifng and Foxp3 expression compared to control-treated cells. Moreover, STAT5 cooperates with transcription factors Ets1 and Runx1 to mediate epigenetic modification and regulate gene expression. Thus, our study has revealed an essential function of Batf in modulating the IL-2-STAT5 signaling to promote and stabilize Th17 cell development.
Project description:Th17 cells secrete IL-17A, IL-17F, IL-21, and IL-22 cytokines that are critical in mediating inflammation and protecting the host from microorganisms infection. The basic leucine zipper transcription factor ATF-like (Batf) contributes to the transcriptional programming of multiple effector T cells, and is required for Th17 cell development. Here, we have interrogated mechanisms by which Batf promotes and stabilizes Th17 cell phenotype. We have shown that in vitro differentiated Th17 cells have increased expression of Th1 and Treg signature genes in the absence of Batf. In addition, Citrobacter rodentium infected Batf-deficient (Batf KO) mice fail to clear the infection, and that is correlated with diminished IL-17A and IL-22 cytokine production and increased Foxp3 and Ifng expression compared to WT mice. We find that Batf sustains Th17 phenotype in long-term culture conditions by suppressing Th1- and Treg-specific gene expression. Mechanistically, we reveal that Batf negatively regulates IL-2-STAT5 signaling and modulates STAT5 binding at the Ifng and Foxp3 gene loci thus suppressing Th1-Treg phenotype in Th17 cell development. Inhibition of STAT5 DNA binding activity in Batf KO Th17 cells was able to repress Ifng and Foxp3 expression compared to control-treated cells. Moreover, STAT5 cooperates with transcription factors Ets1 and Runx1 to mediate epigenetic modification and regulate gene expression. Thus, our study has revealed an essential function of Batf in modulating the IL-2-STAT5 signaling to promote and stabilize Th17 cell development.
Project description:Peripheral infections can result in neuropsychiatric changes in many contexts, including after recurrent Group A Streptococcus (GAS) infections in children. In a mouse model of intranasal GAS inoculation, we have previously demonstrated in vivo that mice lacking Th17 cells, or the key Th17 cytokines interleukin 17A (IL-17A) or granulocyte-macrophage colony-stimulating factor (GM-CSF), have altered microglial responses. As an attempt to determine whether these cytokines have direct effects on microglia, we cultured primary microglia and incubated them with either interferon gamma (IFNg), IL-17A or GM-CSF for 24 hours, then collected RNA for bulk sequencing. Microglia treated with IFNg or GM-CSF displayed striking transcriptional shifts, including upregulation of many inflammatory genes. IL-17A treatment did not have a noticeable effect on the microglial transcriptome, likely due to the in vitro absence of IL-17A receptors, which are expressed by microglia in vivo.
Project description:Single-cell RNA-sequencing of in vitro differentiated T cells cultured with IL-12+IL-21+IL-23 (Th1 cell condition) or IL-1b+IL-6+IL-23 (pathogenic Th17 cell condition)