scholarly journals Secondary nucleation of monomers on fibril surface dominatesα-synuclein aggregation and provides autocatalytic amyloid amplification

2017 ◽  
Vol 50 ◽  
Author(s):  
Ricardo Gaspar ◽  
Georg Meisl ◽  
Alexander K. Buell ◽  
Laurence Young ◽  
Clemens F. Kaminski ◽  
...  
Keyword(s):  
Significant Contribution ◽  
Lewy Bodies ◽  
Monomer Concentration ◽  
Super Resolution ◽  
Secondary Process ◽  
Secondary Nucleation ◽  
Lewy Neurites ◽  
Rapid Generation ◽  
Differential Sedimentation ◽  
Super Resolution Microscopy

AbstractParkinson's disease (PD) is characterized by proteinaceous aggregates named Lewy Bodies and Lewy Neurites containingα-synuclein fibrils. The underlying aggregation mechanism of this protein is dominated by a secondary process at mildly acidic pH, as in endosomes and other organelles. This effect manifests as a strong acceleration of the aggregation in the presence of seeds and a weak dependence of the aggregation rate on monomer concentration. The molecular mechanism underlying this process could be nucleation of monomers on fibril surfaces or fibril fragmentation. Here, we aim to distinguish between these mechanisms. The nature of the secondary processes was investigated using differential sedimentation analysis, trap and seed experiments, quartz crystal microbalance experiments and super-resolution microscopy. The results identify secondary nucleation of monomers on the fibril surface as the dominant secondary process leading to rapid generation of new aggregates, while no significant contribution from fragmentation was found. The newly generated oligomeric species quickly elongate to further serve as templates for secondary nucleation and this may have important implications in the spreading of PD.

scholarly journals Lewy pathology in Parkinson’s disease consists of a crowded organellar, membranous medley

2017 ◽  
Author(s):  
Sarah H. Shahmoradian ◽  
Amanda J. Lewis ◽  
Christel Genoud ◽  
Jürgen Hench ◽  
Tim Moors ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Light And Electron Microscopy ◽  
Lewy Bodies ◽  
Super Resolution ◽  
Confocal Imaging ◽  
Postmortem Brain ◽  
Lewy Neurites ◽  
Lewy Pathology ◽  
Age Related

SummaryParkinson’s disease, the most common age-related movement disorder, is a progressive neurodegenerative disease with unclear etiology. Key neuropathological hallmarks are Lewy bodies and Lewy neurites, which are neuronal inclusions that are immunopositive for the protein α-synuclein. In-depth ultrastructural analysis of this Lewy pathology is crucial to understanding pathogenesis and progression of the disease. Using correlative light and electron microscopy/tomography on brain tissue from five Parkinson’s disease brain donors, we identified α-synuclein immunopositive Lewy pathology and could show that the majority of these features including Lewy bodies and Lewy neurites primarily consists of a crowded membranous medley of vesicular structures and dysmorphic organelles. Only a small fraction of observed Lewy bodies contained predominant proteinaceous filaments, as previously described. The crowding of organellar components was confirmed by STED- based super-resolution microscopy, and high lipid content within the α-synuclein immunopositive inclusions was corroborated by confocal imaging, CARS/FTIR imaging and lipidomics. Applying this correlative high-resolution imaging and biophysical approach, we discovered in the postmortem brain of Parkinson’s patients a subcellular protein-lipid compartmentalization not previously described in Lewy pathology.

scholarly journals Size-dependent secondary nucleation and amplification of α-synuclein amyloid fibrils

2021 ◽  
Author(s):  
Arunima Sakunthala ◽  
Debalina Datta ◽  
Ambuja Navalkar ◽  
Laxmikant Gadhe ◽  
Pradeep Kadu ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Super Resolution ◽  
Cellular Internalization ◽  
Biological Processes ◽  
Secondary Nucleation ◽  
Size Dependent ◽  
Distinct Mechanism ◽  
In Vitro Reconstitution ◽  
Super Resolution Microscopy

The size of the amyloid seeds is known to modulate their autocatalytic amplification and cellular toxicity. However, the seed size-dependent secondary nucleation mechanism, toxicity, and disease-associated biological processes mediated by α-synuclein (α-Syn) fibrils are largely unknown. Using the cellular model and in vitro reconstitution, we showed that the size of α-Syn fibril seeds not only dictates its cellular internalization and associated cell death; but also the distinct mechanisms of fibril amplification pathways involved in the pathological conformational change of α-Syn. Specifically, small-sized fibril seeds showed elongation possibly through monomer addition at the fibril termini; whereas longer fibrils template the fibril amplification by surface-mediated nucleation as demonstrated by super-resolution microscopy. The distinct mechanism of fibril amplification, and cellular uptake along with toxicity suggest that breakage of fibrils into different sizes of seeds determine the underlying pathological outcome of synucleinopathies.

Super-Resolution Microscopy in Studying the Structure and Function of the Cell Nucleus

Acta Naturae ◽  
2017 ◽  
Vol 9 (4) ◽  
pp. 42-51
Author(s):  
S. S. Ryabichko ◽  
◽  
A. N. Ibragimov ◽  
L. A. Lebedeva ◽  
E. N. Kozlov ◽  
...  
Keyword(s):  
Cell Nucleus ◽  
Super Resolution ◽  
Structure And Function ◽  
And Function ◽  
Super Resolution Microscopy

Structural Evidence of Photoisomerization Pathways in Fluorescent Proteins

2019 ◽  
Author(s):  
Jeffrey Chang ◽  
Matthew Romei ◽  
Steven Boxer
Keyword(s):  
Rational Design ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Super Resolution ◽  
Unit Cell Size ◽  
Chlorine Substituent ◽  
Gfp Chromophore ◽  
The One ◽  
Green Fluorescent ◽  
Super Resolution Microscopy

<p>Double-bond photoisomerization in molecules such as the green fluorescent protein (GFP) chromophore can occur either via a volume-demanding one-bond-flip pathway or via a volume-conserving hula-twist pathway. Understanding the factors that determine the pathway of photoisomerization would inform the rational design of photoswitchable GFPs as improved tools for super-resolution microscopy. In this communication, we reveal the photoisomerization pathway of a photoswitchable GFP, rsEGFP2, by solving crystal structures of <i>cis</i> and <i>trans</i> rsEGFP2 containing a monochlorinated chromophore. The position of the chlorine substituent in the <i>trans</i> state breaks the symmetry of the phenolate ring of the chromophore and allows us to distinguish the two pathways. Surprisingly, we find that the pathway depends on the arrangement of protein monomers within the crystal lattice: in a looser packing, the one-bond-flip occurs, whereas in a tighter packing (7% smaller unit cell size), the hula-twist occurs.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p> <p> </p>

Novel organic dyes for multicolor localization-based super-resolution microscopy

2015 ◽  
Vol 9 (1-2) ◽  
pp. 161-170 ◽  
Author(s):  
Martin Lehmann ◽  
Gregor Lichtner ◽  
Haider Klenz ◽  
Jan Schmoranzer
Keyword(s):  
Organic Dyes ◽  
Super Resolution ◽  
Super Resolution Microscopy

scholarly journals Fibroblast Growth Factor 20 Gene Polymorphism in Parkinson’s Disease in Asian Population: A Meta-Analysis

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 674
Author(s):  
Han-Lin Chiang ◽  
Yih-Ru Wu ◽  
Yi-Chun Chen ◽  
Hon-Chung Fung ◽  
Chiung-Mei Chen
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Meta Analysis ◽  
Lewy Bodies ◽  
Asian Population ◽  
Protective Role ◽  
Lewy Neurites ◽  
Chinese Populations ◽  
Study Results

Parkinson’s disease (PD) is a neurodegenerative disease with the pathological hallmark of Lewy bodies and Lewy neurites composed of α-synuclein. The SNP rs591323 is one of the risk loci located near the FGF20 gene that has been implicated in PD. The variation of FGF20 in the 3′ untranslated region was shown to increase α-synuclein expression. We examined the association of rs591323 with the risk of PD in a Taiwanese population and conducted a meta-analysis, including our study and two other studies from China, to further confirm the role of this SNP in Taiwanese/Chinese populations. A total of 586 patients with PD and 586 health controls (HCs) were included in our study. We found that the minor allele (A) and the AA + GA genotype under the dominant model are significantly less frequent in PD than in controls. The meta-analysis consisted of 1950 patients with PD and 2073 healthy controls from three studies. There was significant association between rs591323 and the risk of PD in the additive (Z = −3.96; p < 0.0001) and the dominant models (Z = −4.01; p < 0.0001). Our study results and the meta-analysis support the possible protective role of the rs591323 A allele in PD in Taiwanese/Chinese populations.

scholarly journals Bio-orthogonal Red and Far-Red Fluorogenic Probes for Wash-Free Live-Cell and Super-resolution Microscopy

2021 ◽  
Author(s):  
Philipp Werther ◽  
Klaus Yserentant ◽  
Felix Braun ◽  
Kristin Grußmayer ◽  
Vytautas Navikas ◽  
...  
Keyword(s):  
Super Resolution ◽  
Live Cell ◽  
Fluorogenic Probes ◽  
Super Resolution Microscopy
Sign in / Sign up

Export Citation Format

Share Document