Alpha synuclein aggregation: is it the toxic gain of function responsible for neurodegeneration in Parkinson's disease?

2001 ◽  
Vol 122 (14) ◽  
pp. 1499-1510 ◽  
Author(s):  
Subramianian Rajagopalan ◽  
Julie K Andersen
2017 ◽  
Vol 114 (40) ◽  
pp. 10773-10778 ◽  
Author(s):  
Seong Su Kang ◽  
Zhentao Zhang ◽  
Xia Liu ◽  
Fredric P. Manfredsson ◽  
Matthew J. Benskey ◽  
...  

BDNF/TrkB neurotrophic signaling is essential for dopaminergic neuronal survival, and the activities are reduced in the substantial nigra (SN) of Parkinson’s disease (PD). However, whether α-Syn (alpha-synuclein) aggregation, a hallmark in the remaining SN neurons in PD, accounts for the neurotrophic inhibition remains elusive. Here we show that α-Syn selectively interacts with TrkB receptors and inhibits BDNF/TrkB signaling, leading to dopaminergic neuronal death. α-Syn binds to the kinase domain on TrkB, which is negatively regulated by BDNF or Fyn tyrosine kinase. Interestingly, α-Syn represses TrkB lipid raft distribution, decreases its internalization, and reduces its axonal trafficking. Moreover, α-Syn also reduces TrkB protein levels via up-regulation of TrkB ubiquitination. Remarkably, dopamine’s metabolite 3,4-Dihydroxyphenylacetaldehyde (DOPAL) stimulates the interaction between α-Syn and TrkB. Accordingly, MAO-B inhibitor rasagiline disrupts α-Syn/TrkB complex and rescues TrkB neurotrophic signaling, preventing α-Syn–induced dopaminergic neuronal death and restoring motor functions. Hence, our findings demonstrate a noble pathological role of α-Syn in antagonizing neurotrophic signaling, providing a molecular mechanism that accounts for its neurotoxicity in PD.


2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
A. R. Esteves ◽  
D. M. Arduíno ◽  
D. F. F. Silva ◽  
C. R. Oliveira ◽  
S. M. Cardoso

While the etiology of Parkinson's disease remains largely elusive, there is accumulating evidence suggesting that mitochondrial dysfunction occurs prior to the onset of symptoms in Parkinson's disease. Mitochondria are remarkably primed to play a vital role in neuronal cell survival since they are key regulators of energy metabolism (as ATP producers), of intracellular calcium homeostasis, of NAD+/NADH ratio, and of endogenous reactive oxygen species production and programmed cell death. In this paper, we focus on mitochondrial dysfunction-mediated alpha-synuclein aggregation. We highlight some of the findings that provide proof of evidence for a mitochondrial metabolism control in Parkinson's disease, namely, mitochondrial regulation of microtubule-dependent cellular traffic and autophagic lysosomal pathway. The knowledge that microtubule alterations may lead to autophagic deficiency and may compromise the cellular degradation mechanisms that culminate in the progressive accumulation of aberrant protein aggregates shields new insights to the way we address Parkinson's disease. In line with this knowledge, an innovative window for new therapeutic strategies aimed to restore microtubule network may be unlocked.


2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Peng Wang ◽  
Xin Li ◽  
Xuran Li ◽  
Weiwei Yang ◽  
Shun Yu

A pathological hallmark of Parkinson’s disease (PD) is formation of Lewy bodies in neurons of the brain. This has been attributed to the spread of α-synuclein (α-syn) aggregates, which involves release of α-syn from a neuron and its reuptake by a neighboring neuron. We found that treatment with plasma from PD patients induced more α-syn phosphorylation and oligomerization than plasma from normal subjects (NS). Compared with NS plasma, PD plasma added to primary neuron cultures caused more cell death in the presence of extracellular α-syn. This was supported by the observations that phosphorylated α-syn oligomers entered neurons, rapidly increased accumulated thioflavin S-positive inclusions, and induced a series of metabolic changes that included activation of polo-like kinase 2, inhibition of glucocerebrosidase and protein phosphatase 2A, and reduction of ceramide levels, all of which have been shown to promote α-syn phosphorylation and aggregation. We also analyzed neurotoxicity of α-syn oligomers relative to plasma from different patients. Neurotoxicity was not related to age or gender of the patients. However, neurotoxicity was positively correlated with H&Y staging score. The modification in the plasma may promote spreading of α-syn aggregates via an alternative pathway and accelerate progression of PD.


2018 ◽  
Vol 9 (5) ◽  
pp. 799-814 ◽  
Author(s):  
P. Perez-Pardo ◽  
H.B. Dodiya ◽  
P.A. Engen ◽  
A. Naqib ◽  
C.B. Forsyth ◽  
...  

The mechanism of neurodegeneration in Parkinson’s disease (PD) remains unknown but it has been hypothesised that the intestinal tract could be an initiating and contributing factor to the neurodegenerative processes. In PD patients as well as in animal models for PD, alpha-synuclein-positive enteric neurons in the colon and evidence of colonic inflammation have been demonstrated. Moreover, several studies reported pro-inflammatory bacterial dysbiosis in PD patients. Here, we report for the first time significant changes in the composition of caecum mucosal associated and luminal microbiota and the associated metabolic pathways in a rotenone-induced mouse model for PD. The mouse model for PD, induced by the pesticide rotenone, is associated with an imbalance in the gut microbiota, characterised by a significant decrease in the relative abundance of the beneficial commensal bacteria genus Bifidobacterium. Overall, intestinal bacterial dysbiosis might play an important role in both the disruption of intestinal epithelial integrity and intestinal inflammation, which could lead or contribute to the observed alpha-synuclein aggregation and PD pathology in the intestine and central nervous system in the oral rotenone mouse model of PD.


2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Noah Joseph Kozub ◽  
Taylor Van Brysgel ◽  
Christopher Anthony Yerxa ◽  
Stephen Moss ◽  
Victoria Melina Haak ◽  
...  

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Nora Bengoa-Vergniory ◽  
Emilie Faggiani ◽  
Paula Ramos-Gonzalez ◽  
Ecem Kirkiz ◽  
Natalie Connor-Robson ◽  
...  

Abstract Parkinson’s disease (PD) affects millions of patients worldwide and is characterized by alpha-synuclein aggregation in dopamine neurons. Molecular tweezers have shown high potential as anti-aggregation agents targeting positively charged residues of proteins undergoing amyloidogenic processes. Here we report that the molecular tweezer CLR01 decreased aggregation and toxicity in induced pluripotent stem cell-derived dopaminergic cultures treated with PD brain protein extracts. In microfluidic devices CLR01 reduced alpha-synuclein aggregation in cell somas when axonal terminals were exposed to alpha-synuclein oligomers. We then tested CLR01 in vivo in a humanized alpha-synuclein overexpressing mouse model; mice treated at 12 months of age when motor defects are mild exhibited an improvement in motor defects and a decreased oligomeric alpha-synuclein burden. Finally, CLR01 reduced alpha-synuclein-associated pathology in mice injected with alpha-synuclein aggregates into the striatum or substantia nigra. Taken together, these results highlight CLR01 as a disease-modifying therapy for PD and support further clinical investigation.


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