2. Academic Validation
  3. A functionalized hydroxydopamine quinone links thiol modification to neuronal cell death

A functionalized hydroxydopamine quinone links thiol modification to neuronal cell death

  • Redox Biol. 2020 Jan;28:101377. doi: 10.1016/j.redox.2019.101377.
Ali Farzam 1,  Karan Chohan 2,  Miroslava Strmiskova 1,  Sarah J Hewitt 3,  David S Park 3,  John P Pezacki 4,  Dennis Özcelik 5
Affiliations

Affiliations

  • 1 Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada.
  • 2 Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
  • 3 University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
  • 4 Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
  • 5 Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada. Electronic address: [email protected].
PMID: 31760358 DOI: 10.1016/j.redox.2019.101377
Abstract

Recent findings suggest that dopamine oxidation contributes to the development of Parkinson's disease (PD); however, the mechanistic details remain elusive. Here, we compare 6-hydroxydopamine (6-OHDA), a product of dopamine oxidation that commonly induces dopaminergic neurodegeneration in laboratory Animals, with a synthetic alkyne-functionalized 6-OHDA variant. This synthetic molecule provides insights into the reactivity of quinone and neuromelanin formation. Employing Huisgen cycloaddition chemistry (or "click chemistry") and fluorescence imaging, we found that reactive 6-OHDA p-quinones cause widespread protein modification in isolated proteins, lysates and cells. We identified cysteine thiols as the target site and investigated the impact of proteome modification by Quinones on cell viability. Mass spectrometry following cycloaddition chemistry produced a large number of 6-OHDA modified targets including proteins involved in redox regulation. Functional in vitro assays demonstrated that 6-OHDA inactivates protein disulfide isomerase (PDI), which is a central player in protein folding and redox homeostasis. Our study links dopamine oxidation to protein modification and protein folding in dopaminergic neurons and the PD model.

Keywords

6-Hydroxydopamine p-quinone; Dopamine oxidation; Neurotoxicity; Parkinson's disease; Post-translational protein modification; Protein disulfide isomerase.

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