scholarly journals Interactions between SARS-CoV-2 N-protein and α-synuclein accelerate amyloid formation

2021 ◽  
Author(s):  
Slav Semerdzhiev ◽  
Mohammad Amin Abolghassemi Fakhree ◽  
Ine Segers-Nolten ◽  
Christian Blum ◽  
Mireille M.A.E. Claessens

First cases that point at a correlation between SARS-CoV-2 infections and the development of Parkinson's disease have been reported. Currently it is unclear if there also is a direct causal link between these diseases. To obtain first insights into a possible molecular relation between viral infections and the aggregation of α-synuclein protein into amyloid fibrils characteristic for Parkinson's disease, we investigated the effect of the presence of SARS-CoV-2 proteins on α synuclein aggregation. We show, in test tube experiments, that SARS-CoV-2 S-protein has no effect on α-synuclein aggregation while SARS-CoV-2 N-protein considerably speeds up the aggregation process. We observe the formation of multi-protein complexes, and eventually amyloid fibrils. Microinjection of N-protein in SHSY-5Y cells disturbed the α-synuclein proteostasis and increased cell death. Our results point toward direct interactions between the N-protein of SARS-CoV-2 and α-synuclein as molecular basis for the observed coincidence between SARS-CoV-2 infections and Parkinsonism.

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Mehri Salari ◽  
Bahareh Zaker Harofteh ◽  
Masoud Etemadifar ◽  
Nahad Sedaghat ◽  
Hosein Nouri

As neurological complications associated with COVID-19 keep unfolding, the number of cases with COVID-19-associated de novo movement disorders is rising. Although no clear pathomechanistic explanation is provided yet, the growing number of these cases is somewhat alarming. This review gathers information from 64 reports of de novo movement disorders developing after/during infection with SARS-CoV-2. Three new cases with myoclonus occurring shortly after a COVID-19 infection are also presented. Treatment resulted in partial to complete recovery in all three cases. Although the overall percentage of COVID-19 patients who develop movement disorders is marginal, explanations on a probable causal link have been suggested by numerous reports; most commonly involving immune-mediated and postinfectious and less frequently hypoxic-associated and ischemic-related pathways. The current body of evidence points myoclonus and ataxia out as the most frequent movement disorders occurring in COVID-19 patients. Some cases of tremor, chorea, and hypokinetic-rigid syndrome have also been observed in association with COVID-19. In particular, parkinsonism may be of dual concern in the setting of COVID-19; some have linked viral infections with Parkinson’s disease (PD) based on results from cerebrospinal fluid analyses, and PD is speculated to impact the outcome of COVID-19 in patients negatively. In conclusion, the present paper reviewed the demographic, clinical, and treatment-associated information on de novo movement disorders in COVID-19 patients in detail; it also underlined the higher incidence of myoclonus and ataxia associated with COVID-19 than other movement disorders.


2019 ◽  
Vol 294 (25) ◽  
pp. 9973-9984 ◽  
Author(s):  
Ryan P. McGlinchey ◽  
Shannon M. Lacy ◽  
Katherine E. Huffer ◽  
Nahid Tayebi ◽  
Ellen Sidransky ◽  
...  

A pathological feature of Parkinson's disease (PD) is Lewy bodies (LBs) composed of α-synuclein (α-syn) amyloid fibrils. α-Syn is a 140 amino acids–long protein, but truncated α-syn is enriched in LBs. The proteolytic processes that generate these truncations are not well-understood. On the basis of our previous work, we propose that these truncations could originate from lysosomal activity attributable to cysteine cathepsins (Cts). Here, using a transgenic SNCAA53T mouse model, overexpressing the PD-associated α-syn variant A53T, we compared levels of α-syn species in purified brain lysosomes from nonsymptomatic mice with those in age-matched symptomatic mice. In the symptomatic mice, antibody epitope mapping revealed enrichment of C-terminal truncations, resulting from CtsB, CtsL, and asparagine endopeptidase. We did not observe changes in individual cathepsin activities, suggesting that the increased levels of C-terminal α-syn truncations are because of the burden of aggregated α-syn. Using LC-MS and purified α-syn, we identified C-terminal truncations corresponding to amino acids 1–122 and 1–90 from the SNCAA53T lysosomes. Feeding rat dopaminergic N27 cells with exogenous α-syn fibrils confirmed that these fragments originate from incomplete fibril degradation in lysosomes. We mimicked these events in situ by asparagine endopeptidase degradation of α-syn fibrils. Importantly, the resulting C-terminally truncated fibrils acted as superior seeds in stimulating α-syn aggregation compared with that of the full-length fibrils. These results unequivocally show that C-terminal α-syn truncations in LBs are linked to Cts activities, promote amyloid formation, and contribute to PD pathogenesis.


Author(s):  
Maarten C. Hardenberg ◽  
Tessa Sinnige ◽  
Sam Casford ◽  
Samuel Dada ◽  
Chetan Poudel ◽  
...  

AbstractMisfolded α-synuclein is a major component of Lewy bodies, which are a hallmark of Parkinson’s disease. A large body of evidence shows that α-synuclein can self-assemble into amyloid fibrils, but the relationship between amyloid formation and Lewy body formation still remains unclear. Here we show, both in vitro and in a C. elegans model of Parkinson’s disease, that α-synuclein undergoes liquid-liquid phase separation by forming a liquid droplet state, which converts into an amyloid-rich hydrogel. This maturation process towards the amyloid state is delayed in the presence of model synaptic vesicles in vitro. Taken together, these results suggest that the formation of Lewy bodies is linked to the arrested maturation of α-synuclein condensates in the presence of lipids and other cellular components.


Author(s):  
Walaa A. Kamel ◽  
Ismail Ibrahim Ismail ◽  
Mohamed Ibrahim ◽  
Jasem Y. Al-Hashel

Abstract Background Parkinson’s disease (PD) is a neurodegenerative condition that has been reported following viral infections in rare occasions. Several neurological complications have emerged in association with coronavirus disease 2019 (COVID-19), since its declaration as a pandemic. Herein, we present a novel case of unexplained worsening of PD as the sole initial presentation of COVID-19, in the absence of fever or respiratory symptoms. Case presentation A 56-year-old male with advanced PD presented with severe rigidity, dystonic posturing of both feet, and confusion of 4 days duration. His condition progressed to an akinetic-rigid state and confusion during the following week, and a routine nasopharyngeal swab tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on the 9th day of onset. He developed fever and dyspnea later and was intubated on the 10th day. Conclusion To our knowledge, worsening of PD symptoms as the sole initial manifestation of SARS-CoV-2 infection, in the absence of other cardinal features of COVID-19, has not been reported in the literature. We suggest testing for COVID-19 infection in patients with PD, especially advanced cases, who present with unexplained worsening of symptoms, even in the absence of COVID-19 cardinal features.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 598
Author(s):  
Jeswinder Sian-Hulsmann ◽  
Peter Riederer

The risk of Parkinson’s disease increases with age. However, the etiology of the illness remains obscure. It appears highly likely that the neurodegenerative processes involve an array of elements that influence each other. In addition, genetic, endogenous, or exogenous toxins need to be considered as viable partners to the cellular degeneration. There is compelling evidence that indicate the key involvement of modified α-synuclein (Lewy bodies) at the very core of the pathogenesis of the disease. The accumulation of misfolded α-synuclein may be a consequence of some genetic defect or/and a failure of the protein clearance system. Importantly, α-synuclein pathology appears to be a common denominator for many cellular deleterious events such as oxidative stress, mitochondrial dysfunction, dopamine synaptic dysregulation, iron dyshomeostasis, and neuroinflammation. These factors probably employ a common apoptotic/or autophagic route in the final stages to execute cell death. The misfolded α-synuclein inclusions skillfully trigger or navigate these processes and thus amplify the dopamine neuron fatalities. Although the process of neuroinflammation may represent a secondary event, nevertheless, it executes a fundamental role in neurodegeneration. Some viral infections produce parkinsonism and exhibit similar characteristic neuropathological changes such as a modest brain dopamine deficit and α-synuclein pathology. Thus, viral infections may heighten the risk of developing PD. Alternatively, α-synuclein pathology may induce a dysfunctional immune system. Thus, sporadic Parkinson’s disease is caused by multifactorial trigger factors and metabolic disturbances, which need to be considered for the development of potential drugs in the disorder.


Author(s):  
Maarten C Hardenberg ◽  
Tessa Sinnige ◽  
Sam Casford ◽  
Samuel Dada ◽  
Chetan Poudel ◽  
...  

Abstract Misfolded α-synuclein is a major component of Lewy bodies, which are a hallmark of Parkinson’s disease. A large body of evidence shows that α-synuclein can aggregate into amyloid fibrils, but the relationship between α-synuclein self-assembly and Lewy body formation remains unclear. Here we show, both in vitro and in a Caenorhabditis elegans model of Parkinson’s disease, that α-synuclein undergoes liquid‒liquid phase separation by forming a liquid droplet state, which converts into an amyloid-rich hydrogel with Lewy-body-like properties. This maturation process towards the amyloid state is delayed in the presence of model synaptic vesicles in vitro. Taken together, these results suggest that the formation of Lewy bodies may be linked to the arrested maturation of α-synuclein condensates in the presence of lipids and other cellular components.


2020 ◽  
Vol 117 (33) ◽  
pp. 20305-20315 ◽  
Author(s):  
Kun Zhao ◽  
Yeh-Jun Lim ◽  
Zhenying Liu ◽  
Houfang Long ◽  
Yunpeng Sun ◽  
...  

Posttranslational modifications (PTMs) of α-synuclein (α-syn), e.g., phosphorylation, play an important role in modulating α-syn pathology in Parkinson’s disease (PD) and α-synucleinopathies. Accumulation of phosphorylated α-syn fibrils in Lewy bodies and Lewy neurites is the histological hallmark of these diseases. However, it is unclear how phosphorylation relates to α-syn pathology. Here, by combining chemical synthesis and bacterial expression, we obtained homogeneous α-syn fibrils with site-specific phosphorylation at Y39, which exhibits enhanced neuronal pathology in rat primary cortical neurons. We determined the cryo-electron microscopy (cryo-EM) structure of the pY39 α-syn fibril, which reveals a fold of α-syn with pY39 in the center of the fibril core forming an electrostatic interaction network with eight charged residues in the N-terminal region of α-syn. This structure composed of residues 1 to 100 represents the largest α-syn fibril core determined so far. This work provides structural understanding on the pathology of the pY39 α-syn fibril and highlights the importance of PTMs in defining the polymorphism and pathology of amyloid fibrils in neurodegenerative diseases.


2002 ◽  
Vol 25 (5) ◽  
pp. 580-581
Author(s):  
Bernhard Bogerts

Dr. Northoff's comprehensive comparison of clinical symptoms and neurobiological findings in catatonia with that of Parkinson's disease through integration of various levels of investigation, from neurochemistry up to the subjective experience, is a good example of the new strategies we need to improve our understanding of psychiatric disorders. His multimodal approach, leading to the hypothesis that different pathophysiologies of transcortical “horizontal modulation” and “bottom-up/top-down” – orbitofrontal/basal ganglia – “vertical modulations,” may explain many clinical aspects of catatonia and Parkinson's disease, and thereby fills an important gap in current theories of psychomotor syndromes. However, to analyze more specifically the pathophysiology of catatonia, comparison not only with Parkinson's disease, but also with schizophrenia and anxiety disorders would be helpful. As long as the pathohistological and molecular basis of catatonic syndromes is unknown, theories based mainly on functional considerations remain preliminary.


2019 ◽  
Vol 116 (36) ◽  
pp. 17963-17969 ◽  
Author(s):  
Katsuya Araki ◽  
Naoto Yagi ◽  
Koki Aoyama ◽  
Chi-Jing Choong ◽  
Hideki Hayakawa ◽  
...  

Many neurodegenerative diseases are characterized by the accumulation of abnormal protein aggregates in the brain. In Parkinson’s disease (PD), α-synuclein (α-syn) forms such aggregates called Lewy bodies (LBs). Recently, it has been reported that aggregates of α-syn with a cross-β structure are capable of propagating within the brain in a prionlike manner. However, the presence of cross-β sheet-rich aggregates in LBs has not been experimentally demonstrated so far. Here, we examined LBs in thin sections of autopsy brains of patients with PD using microbeam X-ray diffraction (XRD) and found that some of them gave a diffraction pattern typical of a cross-β structure. This result confirms that LBs in the brain of PD patients contain amyloid fibrils with a cross-β structure and supports the validity of in vitro propagation experiments using artificially formed amyloid fibrils of α-syn. Notably, our finding supports the concept that PD is a type of amyloidosis, a disease featuring the accumulation of amyloid fibrils of α-syn.


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