Clearance of alpha-synuclein oligomeric intermediates via the lysosomal degradation pathway.
Cytoplasmic deposition of alpha-synuclein aggregates is a common pathological feature of many neurodegenerative diseases. Strong evidence for the causative role of alpha-synuclein in these disorders is provided by genetic linkage between this gene and familial Parkinson's disease and by neurodegeneration in transgenic animals that overexpress this protein. In particular, it has been hypothesized that the accumulation of nonfibrillar oligomers of alpha-synuclein, which serve as intermediates for fibrillar inclusion body formation, causes neurodegeneration. However, little is known about how cells handle potentially toxic protein aggregates. Here we demonstrate that cells are capable of clearing preformed alpha-synuclein aggregates via the lysosomal degradation pathway. Consequently, blocking this pathway causes the accumulation of the aggregates in non-neuronal cells, differentiated neuroblastoma cells, and primary cortical neurons. This aggregate clearance occurs in an aggregation stage-specific manner; oligomeric intermediates are susceptible to clearance, whereas mature fibrillar inclusion bodies are not. Neutralization of the acidic compartments leads to the accumulation of alpha-synuclein aggregates and exacerbates alpha-synuclein toxicity in postmitotic neuronal cells, suggesting that the accumulation of oligomeric intermediates may be an important event leading to alpha-synuclein-mediated cell death. These results suggest that enhancing lysosomal function may be a potential therapeutic strategy to halt or even prevent the pathogenesis of Parkinson's disease and other Lewy body diseases.
Lee
He-Jin
HJ
The Parkinson's Institute, Sunnyvale, California 94089, USA.
Khoshaghideh
Farnaz
F
Patel
Smita
S
Lee
Seung-Jae
SJ
D000818:Animals; D019556:COS Cells; D002451:Cell Compartmentation / Q000502:physiology; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D006801:Humans; D002479:Inclusion Bodies / Q000473:pathology; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism*; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity; D009447:Neuroblastoma / Q000378:metabolism; D019636:Neurodegenerative Diseases / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012402:Rotenone / Q000494:pharmacology; D051843:Synucleins; D013997:Time Factors; D014162:Transfection; D014475:Uncoupling Agents / Q000494:pharmacology; D051844:alpha-Synuclein
D004791:Enzyme Inhibitors; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins; C497604:SNCA protein, human; C497606:Snca protein, rat; D051843:Synucleins; D014475:Uncoupling Agents; D051844:alpha-Synuclein; D012402:Rotenone; D004121:Dimethyl Sulfoxide