title: Copper-zinc superoxide dismutase (SOD1) is released by microglial cells and confers neuroprotection against 6-OHDA neurotoxicity.
abstract: Microglial-neuronal interactions are essential for brain physiopathology. In this framework, recent data have changed the concept of microglia from essentially macrophagic cells to crucial elements in maintaining neuronal homeostasis and function through the release of neuroprotective molecules. Using proteomic analysis, here we identify copper-zinc superoxide dismutase (SOD1) as a protein produced and released by cultured rat primary microglia. Evidence for a neuroprotective role of microglia-derived SOD1 resulted from experiments in which primary cerebellar granule neurons (CGNs) were exposed to the dopaminergic toxin 6-hydroxydopamine (6-OHDA). Microglial conditioned medium, in which SOD1 had accumulated, protected CGNs from degeneration, and neuroprotection was abrogated by SOD1 inhibitors. These effects were replicated when exogenous SOD1 was added to a nonconditioned medium. SOD1 neuroprotective action was mediated by increased cell calcium from an external source. Further experiments demonstrated the specificity of SOD1 neuroprotection against 6-OHDA compared to other types of neurotoxic challenges. SOD1, constitutively produced and released by microglia through a lysosomal secretory pathway, is identified here for the first time as an essential component of neuroprotection mediated by microglia. This novel information is relevant to stimulating further studies of microglia-mediated neuroprotection in in vivo models of neurodegenerative diseases.
authors.affiliation: Department of Biology, University of Bologna, Via Selmi 3, Bologna, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Polazzi
authors.forename: Ilaria
authors.initials: I
authors.lastname: Mengoni
authors.forename: Marco
authors.initials: M
authors.lastname: Caprini
authors.forename: Emiliano
authors.initials: E
authors.lastname: Peña-Altamira
authors.forename: Ewelina
authors.initials: E
authors.lastname: Kurtys
authors.forename: Barbara
authors.initials: B
authors.lastname: Monti
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D017628:Microglia / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000378:metabolism*; D016627:Oxidopamine / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism* / Q000494:pharmacology; D000072105:Superoxide Dismutase-1
chemical_list: D018696:Neuroprotective Agents; D016627:Oxidopamine; C000606292:Sod1 protein, rat; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1