Abstractα-synuclein (α-syn) is a main component of Lewy bodies (LB) that occur in many neurodegenerative diseases, including Parkinson's disease (PD), dementia with LB (DLB) and multi-system atrophy. α-syn mutations or amplifications are responsible for a subset of autosomal dominant familial PD cases, and overexpression causes neurodegeneration and motor disturbances in animals. To investigate mechanisms for α-syn accumulation and toxicity, we studied a mouse model of lysosomal enzyme cathepsin D (CD) deficiency, and found extensive accumulation of endogenous α-syn in neurons without overabundance of α-syn mRNA. In addition to impaired macroautophagy, CD deficiency reduced proteasome activity, suggesting an essential role for lysosomal CD function in regulating multiple proteolytic pathways that are important for α-syn metabolism. Conversely, CD overexpression reduces α-syn aggregation and is neuroprotective against α-syn overexpression-induced cell death in vitro. In a C. elegans model, CD deficiency exacerbates α-syn accumulation while its overexpression is protective against α-syn-induced dopaminergic neurodegeneration. Mutated CD with diminished enzymatic activity or overexpression of cathepsins B (CB) or L (CL) is not protective in the worm model, indicating a unique requirement for enzymatically active CD. Our data identify a conserved CD function in α-syn degradation and identify CD as a novel target for LB disease therapeutics.
Lysosomal enzyme cathepsin D protects against alpha-synuclein aggregation and toxicity
Liyan Qiao,S. Hamamichi,Kim A. Caldwell,G. Caldwell,T. Yacoubian,Scott M. Wilson,Zuo-Lei Xie,L. D. Speake,Rachael Parks,Donna M. Crabtree,Qiuli Liang,S. Crimmins,Lonnie E. Schneider,Y. Uchiyama,T. Iwatsubo,Yi Zhou,Lisheng Peng,Y. Lu,D. Standaert,Ken C. Walls,J. Shacka,K. Roth,Jianhua Zhang
Published 2008 in Molecular Brain
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- Publication year
2008
- Venue
Molecular Brain
- Publication date
2008-11-21
- Fields of study
Biology, Medicine
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
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