title: Role of matrix metalloproteinase 3-mediated alpha-synuclein cleavage in dopaminergic cell death.
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.
authors.affiliation: Neurology/Neuroscience Department, Weill Medical College of Cornell University, New York, New York 10065, USA.
authors.forename: Dong-Hee
authors.initials: DH
authors.lastname: Choi
authors.forename: Youn-Jung
authors.initials: YJ
authors.lastname: Kim
authors.forename: Young-Gun
authors.initials: YG
authors.lastname: Kim
authors.forename: Tong H
authors.initials: TH
authors.lastname: Joh
authors.forename: M Flint
authors.initials: MF
authors.lastname: Beal
authors.forename: Yoon-Seong
authors.initials: YS
authors.lastname: Kim
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D016923:Cell Death; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D016631:Lewy Bodies / Q000378:metabolism*; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D010300:Parkinson Disease / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000737:chemistry; D013378:Substantia Nigra / Q000378:metabolism; D051844:alpha-Synuclein / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D051844:alpha-Synuclein; D019278:Matrix Metalloproteinase 3; D004298:Dopamine