TY - JOUR
T1 - Alpha-synuclein aggregation involves a bafilomycin A1-sensitive autophagy pathway
AU - Klucken, Jochen
AU - Poehler, Anne Maria
AU - Ebrahimi-Fakhari, Darius
AU - Schneider, Jacqueline
AU - Nuber, Silke
AU - Rockenstein, Edward
AU - Schlötzer-Schrehardt, Ursula
AU - Hyman, Bradley T.
AU - McLean, Pamela J.
AU - Masliah, Eliezer
AU - Winkler, Juergen
N1 - Funding Information:
sonication and freeze-thawing followed by centrifugation at 4°C This study was supported by the Bavarian State Ministry of for 10 min with 800 rcf as described.2,15,31 Equal amounts of Sciences, Research and the Arts (ForNeuroCell), Hamburg protein (15–40 mg) were separated on 4–12% or 12% Bis-Tris Foundation for International Research and Studies (fellowship gels (Invitrogen, NP0336, NP0343), transferred to a PVDF to D.E.F), Federal Ministry of Education and Research membrane (Immobilon-P, Millipore, IPVH00010) and blocked (01GN0979), the Albert-Raps Foundation, grants of the for 1 h. Incubation with primary antibodies for a-synuclein, University Hospital, Erlangen (ELAN No. 08.11.05.1; IZKF LAMP-1, LAMP-2A or LC3-I/II was followed by signal detection No. TP9), Bavaria California Technology Center (BaCaTeC), using fluorescent-labeled secondary antibodies. Immunoblots Parkinson’s Disease Foundation (fellowship to D.E.F.), and were processed and fluorescent signals were quantified. Blots the NIH grants (AG5131, NS057096, AG03197, AG10435, were also probed for actin or a-tubulin. AG18440, AG022074 and NS038372. Statistical analysis. Statistical analysis for comparison of groups in the in vitro experiments was performed with Student’s t-test. Supplemental Materials
PY - 2012/5
Y1 - 2012/5
N2 - Synucleinopathies like Parkinson disease and dementia with Lewy bodies (DLB) are characterized by α-synuclein aggregates within neurons (Lewy bodies) and their processes (Lewy neurites). Whereas α-synuclein has been genetically linked to the disease process, the pathological relevance of α-synuclein aggregates is still debated. Impaired degradation is considered to result in aggregation of α-synuclein. In addition to the ubiquitin-proteasome degradation, the autophagy-lysosomal pathway (ALP) is involved in intracellular degradation processes for a-synuclein. Here, we asked if modulation of ALP affects α-synuclein aggregation and toxicity. We have identified an induction of the ALP markers LAMP-2A and LC3-II in human brain tissue from DLB patients, in a transgenic mouse model of synucleinopathy, and in a cell culture model for α-synuclein aggregation. ALP inhibition using bafilomycin A1 (BafA1) significantly potentiates toxicity of aggregated α-synuclein species in transgenic mice and in cell culture. Surprisingly, increased toxicity is paralleled by reduced aggregation in both in vivo and in vitro models. The dichotomy of effects on aggregating and nonaggregating species of α-synuclein was specifically sensitive to BafA1 and could not be reproduced by other ALP inhibitors. The present study expands on the accumulating evidence regarding the function of ALP for α-synuclein degradation by isolating an aggregation specific, BafA1-sensitive, ALP-related pathway. Our data also suggest that protein aggregation may represent a detoxifying event rather than being causal for cellular toxicity.
AB - Synucleinopathies like Parkinson disease and dementia with Lewy bodies (DLB) are characterized by α-synuclein aggregates within neurons (Lewy bodies) and their processes (Lewy neurites). Whereas α-synuclein has been genetically linked to the disease process, the pathological relevance of α-synuclein aggregates is still debated. Impaired degradation is considered to result in aggregation of α-synuclein. In addition to the ubiquitin-proteasome degradation, the autophagy-lysosomal pathway (ALP) is involved in intracellular degradation processes for a-synuclein. Here, we asked if modulation of ALP affects α-synuclein aggregation and toxicity. We have identified an induction of the ALP markers LAMP-2A and LC3-II in human brain tissue from DLB patients, in a transgenic mouse model of synucleinopathy, and in a cell culture model for α-synuclein aggregation. ALP inhibition using bafilomycin A1 (BafA1) significantly potentiates toxicity of aggregated α-synuclein species in transgenic mice and in cell culture. Surprisingly, increased toxicity is paralleled by reduced aggregation in both in vivo and in vitro models. The dichotomy of effects on aggregating and nonaggregating species of α-synuclein was specifically sensitive to BafA1 and could not be reproduced by other ALP inhibitors. The present study expands on the accumulating evidence regarding the function of ALP for α-synuclein degradation by isolating an aggregation specific, BafA1-sensitive, ALP-related pathway. Our data also suggest that protein aggregation may represent a detoxifying event rather than being causal for cellular toxicity.
KW - Alpha-synuclein
KW - Dementia with lewy bodies (DLB)
KW - Lewy body
KW - Lysosomal degradation
KW - Parkinson disease (PD)
KW - Protein aggregation
UR - http://www.scopus.com/inward/record.url?scp=84862598619&partnerID=8YFLogxK
U2 - 10.4161/auto.19371
DO - 10.4161/auto.19371
M3 - Article
C2 - 22647715
AN - SCOPUS:84862598619
SN - 1554-8627
VL - 8
SP - 754
EP - 766
JO - Autophagy
JF - Autophagy
IS - 5
ER -