Mutant A53T alpha-synuclein induces neuronal death by increasing mitochondrial autophagy

J Biol Chem. 2011 Mar 25;286(12):10814-24. doi: 10.1074/jbc.M110.132514. Epub 2011 Jan 20.

Abstract

Parkinson disease is characterized by the accumulation of aggregated α-synuclein as the major component of the Lewy bodies. α-Synuclein accumulation in turn leads to compensatory effects that may include the up-regulation of autophagy. Another common feature of Parkinson disease (PD) is mitochondrial dysfunction. Here, we provide evidence that the overactivation of autophagy may be a link that connects the intracellular accumulation of α-synuclein with mitochondrial dysfunction. We found that the activation of macroautophagy in primary cortical neurons that overexpress mutant A53T α-synuclein leads to massive mitochondrial destruction and loss, which is associated with a bioenergetic deficit and neuronal degeneration. No mitochondrial removal or net loss was observed when we suppressed the targeting of mitochondria to autophagosomes by silencing Parkin, overexpressing wild-type Mitofusin 2 and dominant negative Dynamin-related protein 1 or blocking autophagy by silencing autophagy-related genes. The inhibition of targeting mitochondria to autophagosomes or autophagy was also partially protective against mutant A53T α-synuclein-induced neuronal cell death. These data suggest that overactivated mitochondrial removal could be one of the contributing factors that leads to the mitochondrial loss observed in PD models.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Animals
  • Autophagy*
  • Disease Models, Animal
  • GTP Phosphohydrolases
  • Gene Silencing
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mitochondria / genetics
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • Mutation, Missense*
  • Neurons / metabolism*
  • PC12 Cells
  • Parkinson Disease / genetics
  • Parkinson Disease / metabolism*
  • Rats
  • Rats, Wistar
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism
  • alpha-Synuclein / genetics
  • alpha-Synuclein / metabolism*

Substances

  • Membrane Proteins
  • Mitochondrial Proteins
  • alpha-Synuclein
  • Ubiquitin-Protein Ligases
  • parkin protein
  • GTP Phosphohydrolases
  • Mfn2 protein, rat