title: Deubiquitinase Usp8 regulates α-synuclein clearance and modifies its toxicity in Lewy body disease.
abstract: In Parkinson's disease, misfolded α-synuclein accumulates, often in a ubiquitinated form, in neuronal inclusions termed Lewy bodies. An important outstanding question is whether ubiquitination in Lewy bodies is directly relevant to α-synuclein trafficking or turnover and Parkinson's pathogenesis. By comparative analysis in human postmortem brains, we found that ubiquitin immunoreactivity in Lewy bodies is largely due to K63-linked ubiquitin chains and markedly reduced in the substantia nigra compared with the neocortex. The ubiquitin staining in cells with Lewy bodies inversely correlated with the content and pathological localization of the deubiquitinase Usp8. Usp8 interacted and partly colocalized with α-synuclein in endosomal membranes and, both in cells and after purification, it deubiquitinated K63-linked chains on α-synuclein. Knockdown of Usp8 in the Drosophila eye reduced α-synuclein levels and α-synuclein-induced eye toxicity. Accordingly, in human cells, Usp8 knockdown increased the lysosomal degradation of α-synuclein. In the dopaminergic neurons of the Drosophila model, unlike knockdown of other deubiquitinases, Usp8 protected from α-synuclein-induced locomotor deficits and cell loss. These findings strongly suggest that removal of K63-linked ubiquitin chains on α-synuclein by Usp8 is a critical mechanism that reduces its lysosomal degradation in dopaminergic neurons and may contribute to α-synuclein accumulation in Lewy body disease.
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom;
authors.forename: Zoi
authors.initials: Z
authors.lastname: Alexopoulou
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom;
authors.forename: Johannes
authors.initials: J
authors.lastname: Lang
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom;
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Perrett
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom;
authors.forename: Myriam
authors.initials: M
authors.lastname: Elschami
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom;
authors.forename: Madeleine E D
authors.initials: ME
authors.lastname: Hurry
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, MA 02115;
authors.forename: Hyoung Tae
authors.initials: HT
authors.lastname: Kim
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom;
authors.forename: Dimitra
authors.initials: D
authors.lastname: Mazaraki
authors.affiliation: Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom;
authors.forename: Aron
authors.initials: A
authors.lastname: Szabo
authors.affiliation: Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom.
authors.forename: Benedikt M
authors.initials: BM
authors.lastname: Kessler
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, MA 02115;
authors.forename: Alfred Lewis
authors.initials: AL
authors.lastname: Goldberg
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom;
authors.forename: Olaf
authors.initials: O
authors.lastname: Ansorge
authors.affiliation: Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom;
authors.forename: Tudor A
authors.initials: TA
authors.lastname: Fulga
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom; george.tofaris@ndcn.ox.ac.uk.
authors.forename: George K
authors.initials: GK
authors.lastname: Tofaris
mesh_terms: D000818:Animals; D059290:Dopaminergic Neurons / Q000378:metabolism; D004330:Drosophila; D010450:Endopeptidases / Q000502:physiology*; D056827:Endosomal Sorting Complexes Required for Transport / Q000502:physiology*; D006801:Humans; D016631:Lewy Bodies / Q000378:metabolism; D020961:Lewy Body Disease / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism; D008297:Male; D025801:Ubiquitin / Q000032:analysis; D043222:Ubiquitin Thiolesterase / Q000502:physiology*; D054875:Ubiquitination; D051844:alpha-Synuclein / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D025801:Ubiquitin; D051844:alpha-Synuclein; D010450:Endopeptidases; C541534:USP8 protein, human; D043222:Ubiquitin Thiolesterase
keywords: Parkinson’s disease; endosome; neurodegeneration; ubiquitin; ubiquitin ligase