Enhanced autophagy from chronic toxicity of iron and mutant A53T α-synuclein: Implications for neuronal cell death in parkinson disease

Katherine C.M. Chew, Eng Tat Ang, Yee Kit Tai, Fai Tsang, Shun Qiang Lo, Elijah Ong, Wei Yi Ong, Han Ming Shen, Kah Leong Lim, Valina L. Dawson, Ted M. Dawson, Tuck Wah Soong

Research output: Contribution to journalArticle

Abstract

Parkinson disease (PD), a prevalent neurodegenerative motor disorder, is characterized by the rather selective loss of dopaminergic neurons and the presence of α-synuclein-enriched Lewy body inclusions in the substantia nigra of the midbrain. Although the etiology of PD remains incompletely understood, emerging evidence suggests that dysregulated iron homeostasis may be involved. Notably, nigral dopaminergic neurons are enriched in iron, the uptake of which is facilitated by the divalent metal ion transporter DMT1. To clarify the role of iron in PD, we generated SH-SY5Y cells stably expressing DMT1 either singly or in combination with wild type or mutant α-synuclein. We found that DMT1 overexpression dramatically enhances Fe 2+ uptake, which concomitantly promotes cell death. This Fe 2+-mediated toxicity is aggravated by the presence of mutant α-synuclein expression, resulting in increased oxidative stress and DNA damage. Curiously, Fe 2+-mediated cell death does not appear to involve apoptosis. Instead, the phenomenon seems to occur as a result of excessive autophagic activity. Accordingly, pharmacological inhibition of autophagy reverses cell death mediated by Fe 2+ overloading. Taken together, our results suggest a role for iron in PD pathogenesis and provide a mechanism underlying Fe 2+-mediated cell death.

Original languageEnglish (US)
Pages (from-to)33380-33389
Number of pages10
JournalJournal of Biological Chemistry
Volume286
Issue number38
DOIs
StatePublished - Sep 23 2011

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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