Project description:IL-17A has emerged as a pivotal driver of tissue pathology in many immune-mediated inflammatory diseases. Despite sharing 50% sequence homology and the same signalling pathway, the role of IL-17F remains less clear. RNA sequencing of human IL-17 popualtions isolated using a cytokine capture technique identified clear transcriptional differences in IL-17A and IL-17F producing cells, with IL-17A producing cells showing enrichment for cytokine signaling and IL-17F producing cells showing enrichment for cellular replication.
Project description:IL-17A has emerged as a pivotal driver of tissue pathology in many immune-mediated inflammatory diseases. Despite sharing 50% sequence homology and the same signalling pathway, the role of IL-17F remains less clear. ChIP sequencing of human IL-17 popualtions isolated using a cytokine capture technique identified clear epigenetic differences in IL-17A and IL-17F producing cells.
Project description:Molecular profiling of effect of TNFα neutralization in contrast to anti-IL-17A or anti-IL-17F treatment for 28 days in lungs of M. tuberculosis infected C57BL/6 mice. Animals were treated once per week (starting day-1) with anti-mouse IL-17A or IL-17F antibodies (20 mg/kg i.p.), anti-mouse TNFα antibody (10 mg/kg), respective isotype control antibodies. Moreover, infected and non-infected TNFα-deficient mice were also analysed. Gene expression data revealed major changes of inflammatory and immune gene expression signatures 4 weeks post-infection (including host-pathogen interactions, macrophage recruitment, activation and polarization, host-anti-mycobacterial activities, immunomodulatory responses and extracellular matrix metallopeptidases) after TNFα blockade, while IL-17A or IL-17F neutralization elicited only mild changes of few genes without impaired host resistance four weeks after M. tuberculosis infection.
Project description:IL-17A and F are critical cytokines in anti-microbial immunity but also contribute to auto-immune pathologies. Recent evidence suggests that they may be differentially produced by T-helper (Th) cells but the underlying mechanisms remain unknown. To address this question, a logical model containing 82 components and 136 regulatory links was developed and calibrated with original flow cytometry data using naive CD4+ T cells in conditions inducing either IL-17A or F. Model analyses led to the identification of the transcription factors NFAT2A, STAT5A and Smad2 as key components explaining the differential expression of IL-17A and IL-17F, with STAT5A controlling IL-17F expression, and an interplay of NFAT2A, STAT5A and Smad2 controlling IL-17A expression.
Project description:Subsequent to acute injury, skeletal muscle undergoes a stereotypic regenerative process that re-establishes homeostasis. Various types of innate and adaptive immunocytes exert positive or negative influences at specific stages along the course of muscle regeneration. We describe an unanticipated role for gdT cells in promoting healthy tissue recovery after injection of cardiotoxin into murine hindlimb muscle. Within a few days of injury, IL-17A-producing gdT cells displaying primarily Vg6+ antigen receptors accumulated at the wound site. Punctual ablation experiments showed that these cells boosted early inflammatory events, notably recruitment of neutrophils; fostered the proliferation of muscle stem and progenitor cells; and thereby promoted tissue regeneration. Supplementation of mice harboring low numbers of IL-17A+ gdT cells with recombinant IL-17A largely reversed their inflammatory and reparative defects. Unexpectedly, the accumulation and influences of gdT cells in this experimental context were microbiota-dependent, unveiling an orthogonal perspective on the treatment of skeletal muscle pathologies such as catastrophic wounds, wasting, muscular dystrophies and myositides.
Project description:We examined the effect of IL-17 signaling pathway on extracellular matrix (ECM) expression and the involvement of IL-17 signaling pathway in pathogenesis of SSc. To identify differences in the expression pattern of ECM genes in IL-17A- or IL-17F-treated cells, we performed PCR array analysis, consisting of 84 ECM-related genes. Normal human dermal fibroblasts were cultured until they were confluent, and then stimulated with IL-17A or IL-17F for 12 hours, and total RNA was extracted. A mixture of equal amounts of mRNAs from three normal fibroblasts was prepared in the presence or absence of IL-17A or -17F, and mRNA expression profile was evaluated using PCR Array. Normal fibroblasts were obtained by skin biopsies from 3 healthy donors. Fibroblasts from donors were used and treated separately as indicated in the summary. Equal amount total RNA from each donor was pooled prior to gene expression analysis.
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:We examined the effect of IL-17 signaling pathway on extracellular matrix (ECM) expression and the involvement of IL-17 signaling pathway in pathogenesis of SSc. To identify differences in the expression pattern of ECM genes in IL-17A- or IL-17F-treated cells, we performed PCR array analysis, consisting of 84 ECM-related genes. Normal human dermal fibroblasts were cultured until they were confluent, and then stimulated with IL-17A or IL-17F for 12 hours, and total RNA was extracted. A mixture of equal amounts of mRNAs from three normal fibroblasts was prepared in the presence or absence of IL-17A or -17F, and mRNA expression profile was evaluated using PCR Array.