RT Journal Article
SR Electronic
T1 Age-Associated Insolubility of Parkin in Human Midbrain is Linked to Redox Balance and Sequestration of Reactive Dopamine Metabolites
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.11.20.392175
DO 10.1101/2020.11.20.392175
A1 Jacqueline M. Tokarew
A1 Daniel N. El-Kodsi
A1 Nathalie A. Lengacher
A1 Travis K. Fehr
A1 Angela P. Nguyen
A1 Bojan Shutinoski
A1 Brian O’Nuallain
A1 Ming Jin
A1 Jasmine M. Khan
A1 Andy C. H. Ng
A1 Juan Li
A1 Qiubo Jiang
A1 Mei Zhang
A1 Liqun Wang
A1 Rajib Sengupta
A1 Kathryn R. Barber
A1 An Tran
A1 Stephanie Zandee
A1 Xiajun Dong
A1 Clemens R. Scherzer
A1 Alexandre Prat
A1 Eve Tsai
A1 Masashi Takanashi
A1 Nobutaka Hattori
A1 Jennifer A. Chan
A1 Luigi Zecca
A1 Andrew B. West
A1 Arne Holmgren
A1 Lawrence Puente
A1 Gary S. Shaw
A1 Gergely Toth
A1 John M. Woulfe
A1 Peggy Taylor
A1 Julianna J. Tomlinson
A1 Michael G. Schlossmacher
YR 2020
UL http://biorxiv.org/content/early/2020/11/21/2020.11.20.392175.abstract
AB The mechanisms by which parkin protects the adult human brain from Parkinson disease remain incompletely understood. We hypothesized that parkin cysteines participate in redox reactions, which are reflected in its posttranslational modifications. We found that in human control brain, including the S. nigra, parkin is largely insoluble after age 40 years, which is linked to its oxidation, e.g., at Cys95 and Cys253. In mice, oxidative stress increases posttranslational modifications at parkin cysteines and reduces its solubility. Oxidation of recombinant parkin also promotes insolubility and aggregate formation, but in parallel, lowers hydrogen peroxide (H2O2). This thiol-based redox activity is diminished by parkin point mutants, e.g., p.C431F and p.G328E. Intriguingly, in parkin-deficient human brain H2O2 concentrations are elevated. In prkn-null mice, H2O2 levels are dysregulated under oxidative stress conditions, such as acutely by MPTP-toxin exposure or chronically due to a second genetic hit. In dopamine toxicity studies, wild-type parkin, but not disease-linked mutants, protects human dopaminergic M17 cells, in part through lowering H2O2. Parkin also neutralizes reactive, electrophilic dopamine metabolites via adduct formation, which occurs foremost at primate-specific Cys95. Further, wild-type but not p.C95A-mutant parkin augments melanin formation. In sections of normal, adult human midbrain, parkin specifically co-localizes with neuromelanin pigment, frequently within LAMP-3/CD63+ lysosomes. We conclude that oxidative modifications of parkin cysteines are associated with protective outcomes, which include the reduction of H2O2, conjugation of reactive dopamine metabolites, sequestration of radicals within insoluble aggregates, and increased melanin formation. The loss of these redox effects may augment oxidative stress in dopamine producing neurons of mutant PRKN allele carriers, thereby contributing to neurodegeneration.Competing Interest StatementDrs. B. ONuallain, M. Jin, L. Wang, P. Taylor are (or were) employees of BioLegend Inc. (Dedham, MA., USA). The Ottawa Hospital receives payments from BioLegend Inc. related to licensing agreements for immunological reagents related to parkin and α-synuclein. Dr. M. Schlossmacher received travel reimbursements from the Michael J. Fox Foundation for Parkinson Research for participation in industry summits and consulting fees as well as royalties from Genzyme-Sanofi for patents unrelated to this work. Dr. G. Toth is an employee and a shareholder of Cantabio Pharmaceuticals. Dr. A. Holmgren (deceased) served as chairman and senior scientist at IMCO Corporation Ltd AB, Stockholm, Sweden. No additional, potentially competing financial interests are declared. Dr. M. Schlossmacher received travel reimbursements from the Michael J. Fox Foundation for Parkinson Research for participation in industry summits and consulting fees as well as royalties from Genzyme-Sanofi for patents unrelated to this work. Dr. G. Toth is an employee and a shareholder of Cantabio Pharmaceuticals. Dr. A. Holmgren (deceased) served as chairman and senior scientist at IMCO Corporation Ltd AB Stockholm Sweden.