Mathias Gelderblom1, Mattia Gallizioli2, Peter Ludewig2, Vivien Thom2, Priyadharshini Arunachalam2, Björn Rissiek2, Christian Bernreuther2, Markus Glatzel2, Thomas Korn2, Thiruma Valavan Arumugam2, Jan Sedlacik2, Christian Gerloff2, Eva Tolosa2, Anna M Planas2, Tim Magnus1. 1. From the Department of Neurology (M. Gelderblom, P.L., V.T., P.A., B.R., C.G., T.M.), Institute of Neuropathology (C.B., M. Glatzel), Department for Neuroradiological Diagnosis and Intervention (J.S.), and Institute of Immunology (E.T.), University Medical Center Hamburg-Eppendorf, Germany; Department d'Isquèmia Cerebral i Neurodegeneració, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas, Spain (M. Gallizioli, A.M.P.); Department of Neurology, Technical University of Munich, Germany (T.K.); Munich Cluster for Systems Neurology (SyNergy), Germany (T.K.); and Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore (T.V.A.). m.gelderblom@uke.de t.magnus@uke.de. 2. From the Department of Neurology (M. Gelderblom, P.L., V.T., P.A., B.R., C.G., T.M.), Institute of Neuropathology (C.B., M. Glatzel), Department for Neuroradiological Diagnosis and Intervention (J.S.), and Institute of Immunology (E.T.), University Medical Center Hamburg-Eppendorf, Germany; Department d'Isquèmia Cerebral i Neurodegeneració, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas, Spain (M. Gallizioli, A.M.P.); Department of Neurology, Technical University of Munich, Germany (T.K.); Munich Cluster for Systems Neurology (SyNergy), Germany (T.K.); and Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore (T.V.A.).
Abstract
BACKGROUND AND PURPOSE: Inflammatory mechanisms can exacerbate ischemic tissue damage and worsen clinical outcome in patients with stroke. Both αβ and γδ T cells are established mediators of tissue damage in stroke, and the role of dendritic cells (DCs) in inducing the early events of T cell activation and differentiation in stroke is not well understood. METHODS: In a murine model of experimental stroke, we defined the immune phenotype of infiltrating DC subsets based on flow cytometry of surface markers, the expression of ontogenetic markers, and cytokine levels. We used conditional DC depletion, bone marrow chimeric mice, and IL-23 (interleukin-23) receptor-deficient mice to further explore the functional role of DCs. RESULTS: We show that the ischemic brain was rapidly infiltrated by IRF4+/CD172a+ conventional type 2 DCs and that conventional type 2 DCs were the most abundant subset in comparison with all other DC subsets. Twenty-four hours after ischemia onset, conventional type 2 DCs became the major source of IL-23, promoting neutrophil infiltration by induction of IL-17 (interleukin-17) in γδ T cells. Functionally, the depletion of CD11c+ cells or the genetic disruption of the IL-23 signaling abrogated both IL-17 production in γδ T cells and neutrophil infiltration. Interruption of the IL-23/IL-17 cascade decreased infarct size and improved neurological outcome after stroke. CONCLUSIONS: Our results suggest a central role for interferon regulatory factor 4-positive IL-23-producing conventional DCs in the IL-17-dependent secondary tissue damage in stroke.
BACKGROUND AND PURPOSE: Inflammatory mechanisms can exacerbate ischemic tissue damage and worsen clinical outcome in patients with stroke. Both αβ and γδ T cells are established mediators of tissue damage in stroke, and the role of dendritic cells (DCs) in inducing the early events of T cell activation and differentiation in stroke is not well understood. METHODS: In a murine model of experimental stroke, we defined the immune phenotype of infiltrating DC subsets based on flow cytometry of surface markers, the expression of ontogenetic markers, and cytokine levels. We used conditional DC depletion, bone marrow chimeric mice, and IL-23 (interleukin-23) receptor-deficient mice to further explore the functional role of DCs. RESULTS: We show that the ischemic brain was rapidly infiltrated by IRF4+/CD172a+ conventional type 2 DCs and that conventional type 2 DCs were the most abundant subset in comparison with all other DC subsets. Twenty-four hours after ischemia onset, conventional type 2 DCs became the major source of IL-23, promoting neutrophil infiltration by induction of IL-17 (interleukin-17) in γδ T cells. Functionally, the depletion of CD11c+ cells or the genetic disruption of the IL-23 signaling abrogated both IL-17 production in γδ T cells and neutrophil infiltration. Interruption of the IL-23/IL-17 cascade decreased infarct size and improved neurological outcome after stroke. CONCLUSIONS: Our results suggest a central role for interferon regulatory factor 4-positive IL-23-producing conventional DCs in the IL-17-dependent secondary tissue damage in stroke.
Authors: Vivien Häußler; Tristan Daehn; Björn Rissiek; Vanessa Roth; Christian Gerloff; Thiruma V Arumugam; Tim Magnus; Mathias Gelderblom Journal: Neuromolecular Med Date: 2019-09-26 Impact factor: 3.843