Role of matrix metalloproteinase 3-mediated alpha-synuclein cleavage in dopaminergic cell death

J Biol Chem. 2011 Apr 22;286(16):14168-77. doi: 10.1074/jbc.M111.222430. Epub 2011 Feb 17.

Abstract

Evidence suggests that the C-terminal truncation of α-synuclein is equally important as aggregation of α-synuclein in Parkinson disease (PD). Our previous results showed that an endopeptidase, matrix metalloproteinase-3 (MMP3), was induced and activated in dopaminergic (DA) cells upon stress conditions. Here, we report that MMP3 cleaved α-synuclein in vitro and in vivo and that α-synuclein and MMP3 were co-localized in Lewy bodies (LB) in the postmortem brains of PD patients. Incubation of α-synuclein with the catalytic domain of MMP3 (cMMP3) resulted in generation of several peptides, and the peptide profiles of WT α-synuclein (WTsyn) and A53T mutant (A53Tsyn) were different. Combined analysis using mass spectrometry and N-terminal determination revealed that MMP3 generated C-terminally truncated peptides of amino acids 1-78, 1-91, and 1-93 and that A53Tsyn produced significantly higher quantities of these peptides. Similar sizes of peptides were detected in N27 DA cells under oxidative stress and RNA interference to knock down MMP3-attenuated peptide generation. Co-overexpression of cMMP3 with either WTsyn or A53Tsyn led to a reduction in Triton X-100-insoluble aggregates and an increase in protofibril-like small aggregates. In addition, overexpression of the 1-93-amino acid peptide in the substantia nigra led to DA neuronal loss without LB-like aggregate formation. The results strongly indicate that MMP3 digestion of α-synuclein in DA neurons plays a pivotal role in the progression of PD through modulation of α-synuclein in aggregation, LB formation, and neurotoxicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Catalytic Domain
  • Cell Death
  • Dopamine / metabolism*
  • Female
  • Gene Expression Regulation, Enzymologic*
  • Humans
  • Lewy Bodies / metabolism*
  • Matrix Metalloproteinase 3 / metabolism*
  • Parkinson Disease / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Recombinant Proteins / chemistry
  • Substantia Nigra / metabolism
  • alpha-Synuclein / metabolism*

Substances

  • Recombinant Proteins
  • alpha-Synuclein
  • Matrix Metalloproteinase 3
  • Dopamine