Alpha-synuclein aggregation, Ubiquitin proteasome system impairment, and l-Dopa response in zinc-induced Parkinsonism: resemblance to sporadic Parkinson’s disease

2017 ◽  
Vol 444 (1-2) ◽  
pp. 149-160 ◽  
Author(s):  
Vinod Kumar ◽  
Deepali Singh ◽  
Brajesh Kumar Singh ◽  
Shweta Singh ◽  
Namrata Mittra ◽  
...  
2008 ◽  
Vol 363 (1500) ◽  
pp. 2215-2227 ◽  
Author(s):  
Yoshikuni Mizuno ◽  
Nobutaka Hattori ◽  
Shin-ichiro Kubo ◽  
Shigeto Sato ◽  
Kenya Nishioka ◽  
...  

Recent progresses in the pathogenesis of sporadic Parkinson's disease (PD) and genetics of familial PD are reviewed. There are common molecular events between sporadic and familial PD, particularly between sporadic PD and PARK1 -linked PD due to α - synuclein ( SNCA ) mutations. In sporadic form, interaction of genetic predisposition and environmental factors is probably a primary event inducing mitochondrial dysfunction and oxidative damage resulting in oligomer and aggregate formations of α-synuclein. In PARK1 -linked PD, mutant α-synuclein proteins initiate the disease process as they have increased tendency for self-aggregation. As highly phosphorylated aggregated proteins are deposited in nigral neurons in PD, dysfunctions of proteolytic systems, i.e. the ubiquitin–proteasome system and autophagy–lysosomal pathway, seem to be contributing to the final neurodegenerative process. Studies on the molecular mechanisms of nigral neuronal death in familial forms of PD will contribute further on the understanding of the pathogenesis of sporadic PD.


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.


Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 283
Author(s):  
Daniel Aghaie Madsen ◽  
Sissel Ida Schmidt ◽  
Morten Blaabjerg ◽  
Morten Meyer

Parkin and α-synuclein are two key proteins involved in the pathophysiology of Parkinson’s disease (PD). Neurotoxic alterations of α-synuclein that lead to the formation of toxic oligomers and fibrils contribute to PD through synaptic dysfunction, mitochondrial impairment, defective endoplasmic reticulum and Golgi function, and nuclear dysfunction. In half of the cases, the recessively inherited early-onset PD is caused by loss of function mutations in the PARK2 gene that encodes the E3-ubiquitin ligase, parkin. Parkin is involved in the clearance of misfolded and aggregated proteins by the ubiquitin-proteasome system and regulates mitophagy and mitochondrial biogenesis. PARK2-related PD is generally thought not to be associated with Lewy body formation although it is a neuropathological hallmark of PD. In this review article, we provide an overview of post-mortem neuropathological examinations of PARK2 patients and present the current knowledge of a functional interaction between parkin and α-synuclein in the regulation of protein aggregates including Lewy bodies. Furthermore, we describe prevailing hypotheses about the formation of intracellular micro-aggregates (synuclein inclusions) that might be more likely than Lewy bodies to occur in PARK2-related PD. This information may inform future studies aiming to unveil primary signaling processes involved in PD and related neurodegenerative disorders.


Author(s):  
J. Eric Ahlskog

Most of the research into the cause of Lewy disorders has focused on Parkinson’s disease, since that is the best defined of these conditions and, therefore, the most straightforward to study. Dementia with Lewy bodies (DLB) is more difficult to diagnose with certainty, especially in the early years of the disease. What we collectively learn about Parkinson’s disease will likely be very relevant to our understanding of DLB. Multiple investigations have linked Parkinson’s disease to both environmental exposures and genetic factors. However, these associations have all been modest, and none of them accounts for more than a few percent of the contribution to the cause of sporadic Parkinson’s disease (i.e., the attributable risks are low). These investigations are ongoing and hopefully will soon provide a more complete understanding of the cause(s). Perhaps the most important clue to all Lewy conditions is located in the brain: the Lewy body itself. A recent sophisticated analysis of Lewy bodies revealed approximately 300 different component proteins. However, we already knew that Lewy bodies contain high concentrations of a normal protein called alpha synuclein. In fact, Lewy bodies are conventionally identified under the microscope with antibody stains that specifically bind to alpha synuclein. Could this be the crucial protein among the nearly 300? While the alpha synuclein story is focused on Parkinson’s disease, it may be just as relevant to DLB, as we shall see. The story starts with a large Italian-American family with Parkinson’s disease, studied by Dr. Lawrence Golbe and colleagues at the Robert Wood Johnson Medical Center in New Brunswick, New Jersey. In this rare family, many members of multiple generations had been affected by Parkinson’s disease (with Lewy bodies), consistent with a single gene passed on with dominant inheritance. It took a number of years to identify that abnormal gene, which ultimately was proven to be the gene coding for alpha synuclein. It was quickly discovered that this genetic error is not present in usual cases of Parkinson’s disease.


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.


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