Project description:Biomaterials induce an immune response and mobilization of macrophages, yet identification and phenotypic characterization of functional macrophage subsets in vivo remain limited. We performed single-cell RNA sequencing analysis on macrophages sorted from either a biologic matrix [urinary bladder matrix (UBM)] or synthetic biomaterial [polycaprolactone (PCL)]. Implantation of UBM promotes tissue repair through generation of a tissue environment characterized by a T helper 2 (Th2)/interleukin (IL)–4 immune profile, whereas PCL induces a standard foreign body response characterized by Th17/IL-17 and fibrosis. Unbiased clustering and pseudotime analysis revealed distinct macrophage subsets responsible for antigen presentation, chemoattraction, and phagocytosis, as well as a small population with expression profiles of both dendritic cells and skeletal muscle after UBM implantation. In the PCL tissue environment, we identified a CD9 hi+ IL-36y + macrophage subset that expressed Th17-associated molecules. These macrophages were virtually absent in mice lacking the IL-17 receptor, suggesting that they might be involved in IL-17–dependent immune and autoimmune responses. Identification and comparison of the unique phenotypical and functional macrophage subsets in mouse and human tissue samples suggest broad relevance of the new classification. These distinct macrophage subsets demonstrate previously unrecognized myeloid phenotypes involved in different tissue responses and provide targets for potential therapeutic modulation in tissue repair and pathology.
Project description:IL-17 is a key cytokine important for defense against infection and plays a critical role in inflammatory diseases. To understand the diversity and identify a core gene signature among IL-17-producing T cell populations we isolated CD4+ and CD8+ IL-17 producing T cells for RNA sequencing.
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.
Project description:Innate lymphoid cells (ILCs) are crucial for the immune surveillance at mucosal sites. ILCs coordinate early eradication of pathogens and contribute to tissue healing and remodelling, features that are dysfunctional in patients with cystic fibrosis (CF). The mechanisms by which ILCs contribute to CF-immunopathology are ill-defined. Here, we report that group 2 ILCs (ILC2s) transdifferentiated into IL-17-secreting cells in the presence of the epithelial derived-cytokines IL-1β, IL-23 and TGF-β. This conversion was abrogated by IL-4 or vitamin D3. IL-17 producing ILC2s induced IL-8 secretion by epithelial cells and their presence in nasal polyps of CF patients is associated with neutrophilia. Our data suggest that ILC2s undergo transdifferentiation in CF nasal polyps in response to local cytokines, which are induced by infectious agents.
Project description:Group 2 innate lymphoid cells (ILC2s) are linked to type 2 immune diseases but can also molecularly change phenotype and provide type 1 immunity towards pathogens. Here we identify an ILC2 subset which can convert into IL-17 producing NKp44‒ ILC3-like cells. c-Kit and CCR6 define this ILC2 subpopulation which exhibit ILC3 features, including RORγt, which enables the conversion into IL-17 producing cells in response to IL-1β and IL-23. We also report a novel but critical role for TGF-β in promoting the conversion of c-kit‒ ILC2s into RORγt expressing c-Kit+ ILC2s by inducing the upregulation of IL23R, CCR6 and KIT mRNA in these cells. This switch was dependent on RORγt and down-regulation of GATA-3. IL-4 was able to reverse this event supporting a role for this cytokine in maintaining ILC2 identity. Notably, this plasticity has physiological relevance as a subset of RORγt+ ILC2s express the skin homing receptor CCR10 and the frequencies of IL-17‒producing ILC3s are increased at the expense of ILC2s within the lesional skin of psoriatic patients compared to healthy individuals.
Project description:Interleukin 17 (IL-17)-producing gamma delta T (gdT17) cells are one of the major cellular sources of IL-17 under the steady state and in disease. However, gdT17 cell metabolism and its role in tissue homeostasis remain poorly understood. Here, we show that the tissue milieu shapes splenic and intestinal gdT17 cell gene signatures. Conditional deletion of mitochondrial transcription factor A (Tfam) in gdT17 cells significantly affected gdT17 cell maintenance systemically. In vivo deletion of Tfam in gdT17 cells resulted in small intestinal tissue remodeling and increased small intestine length that was caused by the enhanced tuft cell–group 2 innate lymphoid cell (ILC2) circuit in mice. In vitro, IL-22, a cytokine highly produced by gdT17 cells, inhibited IL-13-induced tuft cell differentiation. Mice with Tfam deletion in gdT17 cells also showed dysregulation of the small intestine transcriptome and metabolism with less body weight but enhanced anti-helminth immunity. Thus, our work revealed a critical role of mitochondrial metabolism in gdT17 cell maintenance and in regulating small intestine homeostasis and metabolism.