Endoplasmic reticulum stress and mitochondrial cell death pathways mediate A53T mutant alpha-synuclein-induced toxicity

Wanli W. Smith, Haibing Jiang, Zhong Pei, Yuji Tanaka, Hokuto Morita, Akira Sawa, Valina L. Dawson, Ted M. Dawson, Christopher A. Ross

Research output: Contribution to journalArticlepeer-review

Abstract

Parkinson's disease (PD) is a neurodegenerative movement disorder characterized by selective loss of dopaminergic neurons and the presence of Lewy bodies. Alpha-synuclein is a major component of Lewy bodies in sporadic PD, and mutations in alpha-synuclein cause autosomal-dominant hereditary PD. Here, we generated A53T mutant alpha-synuclein-inducible PC12 cell lines using the Tet-off regulatory system. Inducing expression of A53T alpha-synuclein in differentiated PC12 cells decreased proteasome activity, increased the intracellular ROS level and caused up to ∼40% cell death, which was accompanied by mitochondrial cytochrome C release and elevation of caspase-9 and -3 activities. Cell death was partially blocked by cyclosporine A [an inhibitor of the mitochondrial permeability transition (MPT) process], z-VAD (a pan-caspase inhibitor) and inhibitors of caspase-9 and -3 but not by a caspase-8 inhibitor. Furthermore, induction of A53T alpha-synuclein increased endoplasmic reticulum (ER) stress and elevated caspase-12 activity. RNA interference to knock down caspase-12 levels or salubrinal (an ER stress inhibitor) partially protected against cell death and further reduced A53T toxicity after treatment with z-VAD. Our results indicate that both ER stress and mitochondrial dysfunction contribute to A53T alpha-synuclein-induced cell death. This study sheds light into the pathogenesis of alpha-synuclein cellular toxicity in PD and provides a cell model for screening PD therapeutic agents.

Original languageEnglish (US)
Pages (from-to)3801-3811
Number of pages11
JournalHuman molecular genetics
Volume14
Issue number24
DOIs
StatePublished - Dec 15 2005

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Genetics(clinical)

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