The food additive fast green FCF inhibits α‑synuclein aggregation, disassembles mature fibrils and protects against amyloid-induced neurotoxicity

2021 ◽  
Author(s):  
Fenghua Wang ◽  
Ying Wang ◽  
Luying Jiang ◽  
Wenqian Wang ◽  
Jingcheng Sang ◽  
...  

α-Synuclein (α-syn) aggregates into cytotoxic amyloid fibrils, which are recognized as the defining neuropathological feature of Parkinson’s disease (PD). Therefore, inhibiting α-syn fibrillogenesis and disrupting the preformed fibrils are both...


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.



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.



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.



1995 ◽  
Vol 104 (8) ◽  
pp. 655-661 ◽  
Author(s):  
Peter B. Crino ◽  
Barry Greenberg ◽  
John A. Martin ◽  
Virginia M.-Y. Lee ◽  
William D. Hill ◽  
...  

Dystrophic neurites are present in olfactory epithelium (OE) of patients with Alzheimer's disease (AD), Parkinson's disease (PD), and Down syndrome (DS) and occasionally in normal individuals. Cultured olfactory neuroblasts from AD patients generate carboxy terminal amyloid precursor protein (APP) fragments that contain β-amyloid (Aβ), but it is not known if deposits of Aβ and/or APP fragments occur in the OE of individuals with or without AD, PD, or DS. To determine if Aβ accumulates in the OE in situ, we probed postmortem samples of olfactory mucosa from patients with AD, PD and AD (PD/AD), and DS and AD (DS/AD), as well as from controls, using polyclonal and monoclonal antibodies to Aβ and flanking sequences in APPs. Samples of OE also were examined by thioflavin-S and electron microscopy. Labeling of Aβ was observed in 10 of 12 AD cases, 2 of 3 PD/AD cases, 3 of 4 DS/AD cases, 3 of 10 adult controls, and 4 of 6 fetal cases. The Aβ staining was seen in the basal third of the OE, in axons projecting through the lamina propria, and in metaplastic respiratory epithelium within the OE. Antibodies to other APP domains stained the OE of patients and controls. Thioflavin-S staining was present in the basal third of the OE of 8 of 9 AD patients and several PD/AD and DS/AD patients, but only in rare cells of 3 controls. Electron microscopy did not reveal amyloid fibrils in the OE. These data suggest that deposition of Aβ occurs in a variety of circumstances and is not restricted to patients with AD, PD, or DS.



2016 ◽  
Vol 7 (12) ◽  
pp. 4898-4907 ◽  
Author(s):  
Su-Chun How ◽  
Szu-Ming Yang ◽  
Ai Hsin ◽  
Chia-Ping Tseng ◽  
Shu-Shun Hsueh ◽  
...  

Amyloid fibril formation of hen lysozyme (HEWL) can be attenuated by fast green FCF.



2016 ◽  
Vol 213 (9) ◽  
pp. 1759-1778 ◽  
Author(s):  
Nolwen L. Rey ◽  
Jennifer A. Steiner ◽  
Nazia Maroof ◽  
Kelvin C. Luk ◽  
Zachary Madaj ◽  
...  

Parkinson’s disease (PD) is characterized by the progressive appearance of intraneuronal Lewy aggregates, which are primarily composed of misfolded α-synuclein (α-syn). The aggregates are believed to propagate via neural pathways following a stereotypical pattern, starting in the olfactory bulb (OB) and gut. We hypothesized that injection of fibrillar α-syn into the OB of wild-type mice would recreate the sequential progression of Lewy-like pathology, while triggering olfactory deficits. We demonstrate that injected α-syn fibrils recruit endogenous α-syn into pathological aggregates that spread transneuronally over several months, initially in the olfactory network and later in distant brain regions. The seeded inclusions contain posttranslationally modified α-syn that is Thioflavin S positive, indicative of amyloid fibrils. The spreading α-syn pathology induces progressive and specific olfactory deficits. Thus, we demonstrate that propagating α-syn pathology triggered in the OB is functionally detrimental. Collectively, we have created a mouse model of prodromal PD.



2015 ◽  
Vol 471 (3) ◽  
pp. 323-333 ◽  
Author(s):  
Adelin Gustot ◽  
José Ignacio Gallea ◽  
Rabia Sarroukh ◽  
María Soledad Celej ◽  
Jean-Marie Ruysschaert ◽  
...  

Neuroinflammation largely contributes to the pathogenesis of Parkinson's disease (PD). We show that only α-synuclein (α-syn) fibrils activate the inflammatory cascades; oligomers, thought to be the most harmful species, did not. This suggests that the inflammatory properties rely on fibril-specific structural features.



2019 ◽  
Author(s):  
David R. Boyer ◽  
Binsen Li ◽  
Chuanqi Sun ◽  
Weijia Fan ◽  
Michael R. Sawaya ◽  
...  

AbstractDeposits of amyloid fibrils of α-synuclein are the histological hallmarks of Parkinson’s disease, multiple system atrophy, and dementia with Lewy bodies. Although most cases of these diseases are sporadic, autosomal-dominant hereditary mutations have been linked to Parkinson’s disease and dementia with Lewy bodies. Seeing the changes to the structure of amyloid fibrils bearing these mutations may help to understand these diseases. To this end, we determined the cryo-EM structures of α-synuclein fibrils containing the H50Q hereditary mutation. We find that the H50Q mutation results in two new polymorphs of α-synuclein, which we term Narrow and Wide Fibrils. Both polymorphs recapitulate the conserved kernel formed by residues 50-77 observed in wild-type structures; however, the Narrow and Wide Fibrils reveal that H50Q disrupts a key interaction between H50-E57 on the opposing protofilament, abolishing the extensive protofilament interface formed by preNAC residues in the wild-type “rod” structure. Instead, the Narrow Fibril is formed from a single protofilament and the two protofilaments of the Wide protofilament are held together by only a pair of atoms – the Cɣ atoms from the two threonine 59 sidechains. Further, we find that H50Q forms an intramolecular hydrogen bond with K45 leading to the formation of a novel β-arch formed by residues 36-46 that features an extensive hydrogen-bond network between Y39, T44, and E46. The structures of the H50Q polymorphs help to rationalize the faster aggregation kinetics, higher seeding capacity in biosensor cells, and greater cytotoxicity we observe for H50Q compared to wild-type α-synuclein.



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