Project description:The murine thymus produces discrete γδ T cell subsets making either IFN-γ or IL-17, but the role of the TCR in this developmental process remains controversial. Here we generated a non-transgenic and polyclonal model of reduced TCR expression and signal strength selectively on γδ T cells. Mice haploinsufficient for both CD3γ and CD3δ (CD3DH) showed normal αβ thymocyte subsets but specific defects in γδ T cell development, namely impaired differentiation of IL-17-producing embryonic Vγ6+ (but not adult Vγ4+) γδ T cells and a marked depletion of IFN-γ-producing CD122+ NK1.1+ (Vγ1-biased) γδ T cells throughout life. As result, adult CD3DH mice showed defective peripheral IFN-γ responses and were resistant to experimental cerebral malaria. Thus, strong TCR signaling is required within specific developmental windows with distinct Vγ usage and differential cytokine production by effector γδ T cell subsets. We investigated the transcriptional changes associated with reduced TCRγδ signaling in the CD3DH model. Transcriptome-wide analysis of FACS-purified CD3DH or WT γδ thymocytes from E18 or 6-week was carried looking for patterns of gene expression during ontogeny
Project description:Organismal ageing is associated with loss of immune function and higher incidence of cancer. Whether the γδ T cell pool changes upon organismal ageing is not known. In this study we have characterized γδ T cells in peripheral lymph nodes from old and young mice. We found that the γδ T cell pool is severely altered in old mice. The IL-17 producing γδ lineage becomes dominating while IFN-γ producing γδ1 T cells are declining. γδTCR sequencing revealed no collapse in diversity but oligoclonal expansions in Vγ4 γδ17 subsets. Pro-tumourigenic invariant Vγ6 cells are present only in aged lymph nodes, represent the majority of γδ T cells in the tumour, and are associated with faster tumour progression.
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. Overall design: iNKT (CD3+TCRVb11+6B11+), γδ-T (CD3+TCRγδ+) cells and Tconv (CD3+CD161-; negative for iNKT and γδ-T markers) cells were sorted from peripheral blood samples of SpA patients (n=7) and RA patients (n=5). Sequence-libraries of each sample were sequenced on a NextSeq500 system (Illumina).
Project description:During early embryogenesis microglia arise from yolk sac progenitors populating the developing CNS, where they are maintained as tissue-resident macrophages throughout the organism’s lifespan. Here, we describe an experimental system that allows the specific conditional ablation of microglia in vivo. Strikingly, we found that the microglia compartment was reconstituted within one week following depletion. Microglia repopulation relied entirely on a CNS-resident, internal pool and was independent from bone marrow-derived precursors. Newly formed microglia were found in highly proliferative, organized micro-clusters that dissolve once steady state was achieved. Gene expression profiling revealed prominent expression of Interleukin-1 (IL-1) receptor in proliferating microglia. During the repopulation phase, IL-1 signaling was neutralized by treatment with IL-1 receptor antagonist that impaired microglia proliferation. Hence, microglia harbor a highly efficient potential to restore themselves without contribution of peripheral myeloid cells. IL-1 signaling significantly participates in this restorative proliferation process and is involved in stabilizing microglia maintenance. bone marrow macrophages, wild type microglia, and repopulating microglia
Project description:T cells that encounter cultured ocular pigment epithelial cells in vitro are inhibited from undergoing T cell receptor-triggered activation. Because retinal pigment epithelial (RPE) cells are able to suppress T-cell activation, we studied whether RPE cells could suppress cytokine production by activated T helper (Th) cells. In this study we showed that primary cultured RPE cells greatly suppressed activation of bystander CD4+ T cells in vitro, especially the cytokine production by the target T helper cells (Th1 cells, Th2 cells, Th17 cells, but not Th3 cells). Cultured RPE cells and RPE-supernatants significantly suppressed IL-17 producing CD4+ T cells, and RPE cells fully suppressed polarized Th17 cell lines that induced by recombinant proteins, IL-6 and TGFb2. Moreover, RPE cells failed to suppress IL-17 producing T cells in the presence of rIL-6. In addition, Th17 cells exposed to RPE were suppressed via TGFb, which produce RPE cells. These results indicate that retinal PE cells have immunosuppressive capacity in order to inhibit Th17-type effector T cells. Thus, ocular resident cells play a role in establishing immune regulation in the eye. Retinal pigment epithelium suppresses Th17 cells
Project description:T cells that encounter cultured ocular pigment epithelial cells in vitro are inhibited from undergoing T cell receptor-triggered activation. Because retinal pigment epithelial (RPE) cells are able to suppress T-cell activation, we studied whether RPE cells could suppress cytokine production by activated T helper (Th) cells. In this study we showed that primary cultured RPE cells greatly suppressed activation of bystander CD4+ T cells in vitro, especially the cytokine production by the target T helper cells (Th1 cells, Th2 cells, Th17 cells, but not Th3 cells). Cultured RPE cells and RPE-supernatants significantly suppressed IL-17 producing CD4+ T cells, and RPE cells fully suppressed polarized Th17 cell lines that induced by recombinant proteins, IL-6 and TGFb2. Moreover, RPE cells failed to suppress IL-17 producing T cells in the presence of rIL-6. In addition, Th17 cells exposed to RPE were suppressed via TGFb, which produce RPE cells. These results indicate that retinal PE cells have immunosuppressive capacity in order to inhibit Th17-type effector T cells. Thus, ocular resident cells play a role in establishing immune regulation in the eye. Overall design: Retinal pigment epithelium suppresses Th17 cells
Project description:Background: IL-17 is the defining cytokine of the Th17, Tc17, and γδ T cell populations that plays a critical role in mediating inflammation and autoimmunity. Psoriasis vulgaris is an inflammatory skin disease mediated by Th1 and Th17 cytokines with relevant contributions of IFN-γ, TNF-α, and IL-17. Despite the pivotal role IL-17 plays in psoriasis, and in contrast to the other key mediators involved in the psoriasis cytokine cascade that are capable of inducing broad effects on keratinocytes, IL-17 was demonstrated to regulate the expression of a limited number of genes in monolayer keratinocytes cultured in vitro. Methodology/Principal Findings: Given the clinical efficacy of anti-IL-17 agents is associated with an impressive reduction in a large set of inflammatory genes, we sought a full-thickness skin model that more closely resemble in vivo epidermal architecture. Using a reconstructed human epidermis (RHE), IL-17 was able to upregulate 419 gene probes and downregulate 216 gene probes. As possible explanation for the increased gene induction in the RHE model is that CEBPβ, the transcription factor regulating IL-17-responsive genes, is expressed in differentiated KCs. Conclusions/Significance: The genes identified in IL-17-treated RHE are likely relevant to the IL-17 effects in psoriasis, since ixekizumab (anti-IL-17A agent) strongly suppressed the “RHE” genes in psoriasis patients treated in vivo with this IL-17 antagonist. RHE samples were treated with IFNg, IL-22 and IL-17 and compared with control
Project description:Background & Aims: The IL-23/IL-17 axis plays an important role in the pathogenesis of autoimmune diseases and the pathological consequences of infection. We previously showed that immunopathologic mechanisms mediated by inflammatory monocytes underlie the severe focal liver damage induced by the protozoan parasite, Entamoeba histolytica. Here, we analyze the contribution of the IL-23/IL-17 axis to the induction and subsequent recovery from parasite-induced liver damage. Methods: IL-23p19-/-, IL-17A/F-/-, CCR2-/-, and WT mice were intra-hepatically infected with E. histolytica trophozoites and disease onset and recovery were analyzed by magnetic resonance imaging. The expression of liver-specific genes and proteins during infection was examined by qPCR, microarray, FACS analysis and immunohistochemistry. Immuno-depletion and substitution experiments were performed in IL-23p19-/- and WT mice to investigate the role of IL-13 in disease outcome. Results: Liver damage in infected IL-23p19-/-, IL-17A/F-/-, CCR2-/- mice was strongly attenuated compared with that in WT mice. IL-23p19-/- mice showed reduced expression of IL-17 and CCL2 genes and proteins. Increased numbers of IL-13-producing CD11b+Ly6Clo regenerative monocytes were associated with disease attenuation in IL-23p19-/- mice. Immuno-depletion of IL-13 in IL-23-/- mice reversed this attenuation and treatment of infected WT mice with an IL-13/anti-IL-13-mAb complex supported liver recovery. Conclusions: The IL-23/IL-17 axis plays a critical role in the immunopathology of hepatic amebiasis. IL- 13 secreted by CD11b+Ly6Clo monocytes supports recovery from liver damage. An IL-13/anti-IL13- mAb complex mimics this function, suggesting a novel therapeutic option to support tissue healing after liver damage. Overall design: Total liver RNA was extracted from wildtype and IL23-p19-/- mice previously infected intra-hepatically with E. histolytica trophozoites. The material was isolated 0 hours or 6 hours post infection.
Project description:Recent evidence indicates that DROSHA, DGCR8 and DICER exert non-overlapping functions, including miRNA-independent regulatory mechanisms. It is currently unknown whether miRNA-independent functions of DGCR8 play any role in corticogenesis. Here, by phenotypic comparison of conditional knockout cortices for Dgcr8 and Dicer, we uncover that Dgcr8 deletion, in contrast to Dicer, leads to premature differentiation of neural progenitor cells and overproduction of Tbr1 positive neurons. Remarkably, miRNA depletion does not account for these phenotypic differences, indicating that miRNA-independent functions of DGCR8 are critical for corticogenesis. We propose Tbr1 transcript, bearing evolutionary conserved hairpins that resemble miRNA precursors, as one of DGCR8 targets. Our study uncovers, for the first time in the nervous system, an earlier and stronger phenotype occurring in Dgcr8 compared to Dicer mutant and proposes that this effect is mediated by miRNA-independent functions of DGCR8. Overall design: miRNA expression by deep-sequencing in the cortex of Wild-Type, DICER and DGCR8 conditional knock-out mice. Two mice for each genotype.