scholarly journals Cryo-EM structure of alpha-synuclein fibrils amplified by PMCA from PD and MSA patient brains

2021 ◽  
Author(s):  
Domenic Burger ◽  
Alexis Fenyi ◽  
Luc Bousset ◽  
Henning Stahlberg ◽  
Ronald Melki
Keyword(s):  
Multiple System Atrophy ◽  
Parkinson Disease ◽  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Brain Homogenate ◽  
Alpha Synuclein ◽  
Water Interface ◽  
Control Brain ◽  
Air Water Interface

Synucleinopathies are neurodegenerative diseases related to the aggregation of the protein alpha-synuclein (aSyn). Among these diseases, Parkinson disease (PD) and multiple system atrophy (MSA) are most prevalent. aSyn can readily form different fibrillar polymorphs, if exposed to an air-water interface or by templating with pre-existing fibrils. We here report the structures of three fibrillar polymorphs that were obtained after seeding monomeric aSyn with PD and MSA patients brain homogenates using protein misfolding cyclic amplification (PMCA). Seeding with a control brain homogenate did not produce fibrils, and seeding with other in vitro generated fibrillar polymorphs as a control faithfully produced polymorphs of a different type. The here determined fibril structures from PD and MSA brain tissue represent new folds, which partly resemble that of previously reported in vitro generated fibrils from Y39 phosphorylated aSyn protein. The relevance of these fibrils for synucleinopathies in humans remains to be further investigated.

scholarly journals A novel approach to evaluate alpha-synuclein seeding shows a wide heterogeneity in multiple system atrophy

2021 ◽  
Author(s):  
Ivan Martinez-Valbuena ◽  
Naomi P. Visanji ◽  
Ain Kim ◽  
Heather H. C. Lau ◽  
Raphaella W. L. So ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Multiple System Atrophy ◽  
Parkinson Disease ◽  
Real Time ◽  
Brain Regions ◽  
Alpha Synuclein ◽  
Novel Approach ◽  
Reliable Detection

Several in vitro and in vivo findings have consistently shown that alpha-synuclein derived from multiple system atrophy (MSA) subjects has more seeding capacity than Parkinson disease-derived alpha-synuclein. However, reliable detection of alpha-synuclein derived from MSA using seeded amplification assays, such as the Real-Time Quaking-induced Conversion, has remained challenging. Here we demonstrate that the interaction of the Thioflavin T dye with alpha-synuclein from MSA and Parkinson disease patients can be modulated by the type of salt, pH, and ionic strength used to generate strain-specific reaction buffers. Employing this novel approach, we have generated a streamlined Real-Time Quaking-induced Conversion assay capable of categorizing MSA brains according to their alpha-synuclein seeding behavior, and to unravel a previously unrecognized heterogeneity in seeding activity between different brain regions of a given individual that goes beyond immunohistochemical observations and provide a framework for future molecular subtyping of MSA.

scholarly journals Multiple system atrophy-associated oligodendroglial protein p25α stimulates formation of novel α-synuclein strain with enhanced neurodegenerative potential

2021 ◽  
Author(s):  
Nelson Ferreira ◽  
Hjalte Gram ◽  
Zachary A. Sorrentino ◽  
Emil Gregersen ◽  
Sissel Ida Schmidt ◽  
...  
Keyword(s):  
Multiple System Atrophy ◽  
Protein Misfolding ◽  
Resonance Energy Transfer ◽  
Lewy Bodies ◽  
Resonance Energy ◽  
Alpha Synuclein ◽  
Striatal Neurons ◽  
End Stage ◽  
Intracellular Aggregates

AbstractPathology consisting of intracellular aggregates of alpha-Synuclein (α-Syn) spread through the nervous system in a variety of neurodegenerative disorders including Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy. The discovery of structurally distinct α-Syn polymorphs, so-called strains, supports a hypothesis where strain-specific structures are templated into aggregates formed by native α-Syn. These distinct strains are hypothesised to dictate the spreading of pathology in the tissue and the cellular impact of the aggregates, thereby contributing to the variety of clinical phenotypes. Here, we present evidence of a novel α-Syn strain induced by the multiple system atrophy-associated oligodendroglial protein p25α. Using an array of biophysical, biochemical, cellular, and in vivo analyses, we demonstrate that compared to α-Syn alone, a substoichiometric concentration of p25α redirects α-Syn aggregation into a unique α-Syn/p25α strain with a different structure and enhanced in vivo prodegenerative properties. The α-Syn/p25α strain induced larger inclusions in human dopaminergic neurons. In vivo, intramuscular injection of preformed fibrils (PFF) of the α-Syn/p25α strain compared to α-Syn PFF resulted in a shortened life span and a distinct anatomical distribution of inclusion pathology in the brain of a human A53T transgenic (line M83) mouse. Investigation of α-Syn aggregates in brain stem extracts of end-stage mice demonstrated that the more aggressive phenotype of the α-Syn/p25α strain was associated with an increased load of α-Syn aggregates based on a Förster resonance energy transfer immunoassay and a reduced α-Syn aggregate seeding activity based on a protein misfolding cyclic amplification assay. When injected unilaterally into the striata of wild-type mice, the α-Syn/p25α strain resulted in a more-pronounced motoric phenotype than α-Syn PFF and exhibited a “tropism” for nigro-striatal neurons compared to α-Syn PFF. Overall, our data support a hypothesis whereby oligodendroglial p25α is responsible for generating a highly prodegenerative α-Syn strain in multiple system atrophy.

The Compound ATH434 Prevents Alpha-Synuclein Toxicity in a Murine Model of Multiple System Atrophy

2021 ◽  
pp. 1-11
Author(s):  
David I. Finkelstein ◽  
Jay J. Shukla ◽  
Robert A. Cherny ◽  
Jessica L. Billings ◽  
Eiman Saleh ◽  
...  
Keyword(s):  
Multiple System Atrophy ◽  
Pharmacokinetic Profile ◽  
Alpha Synuclein ◽  
Redox Activity ◽  
Substantia Nigra Pars Compacta ◽  
Drug Candidate ◽  
Older Volunteers ◽  
Control Food ◽  
Alpha Synuclein Aggregation

Background: An elevation in iron levels, together with an accumulation of α-synuclein within the oligodendrocytes, are features of the rare atypical parkinsonian disorder, Multiple System Atrophy (MSA). We have previously tested the novel compound ATH434 (formally called PBT434) in preclinical models of Parkinson’s disease and shown that it is brain-penetrant, reduces iron accumulation and iron mediated redox activity, provides neuroprotection, inhibits alpha synuclein aggregation and lowers the tissue levels of alpha synuclein. The compound was also well-tolerated in a first-in-human oral dosing study in healthy and older volunteers with a favorable, dose-dependent pharmacokinetic profile. Objective: To evaluate the efficacy of ATH434 in a mouse MSA model. Methods: The PLP-α-syn transgenic mouse overexpresses α-synuclein, demonstrates oligodendroglial pathology, and manifests motor and non-motor aspects of MSA. Animals were provided ATH434 (3, 10, or 30 mg/kg/day spiked into their food) or control food for 4 months starting at 12 months of age and were culled at 16 months. Western blot was used to assess oligomeric and urea soluble α-synuclein levels in brain homogenates, whilst stereology was used to quantitate the number of nigral neurons and glial cell inclusions (GCIs) present in the substantia nigra pars compacta. Results: ATH434 reduced oligomeric and urea soluble α-synuclein aggregation, reduced the number of GCIs, and preserved SNpc neurons. In vitro experiments suggest that ATH434 prevents the formation of toxic oligomeric species of synuclein. Conclusion: ATH434 is a promising small molecule drug candidate that has potential to move forward to trial for treating MSA.

scholarly journals Multiple system atrophy: genetic risks and alpha-synuclein mutations

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 2072 ◽  
Author(s):  
Heather T Whittaker ◽  
Yichen Qui ◽  
Conceição Bettencourt ◽  
Henry Houlden
Keyword(s):  
Multiple System Atrophy ◽  
Protein Misfolding ◽  
Research Collaboration ◽  
Late Onset ◽  
Alpha Synuclein ◽  
Common Mechanism ◽  
International Research Collaboration ◽  
Cytoplasmic Inclusions ◽  
Genetic Risks

Multiple system atrophy (MSA) is one of the few neurodegenerative disorders where we have a significant understanding of the clinical and pathological manifestations but where the aetiology remains almost completely unknown. Research to overcome this hurdle is gaining momentum through international research collaboration and a series of genetic and molecular discoveries in the last few years, which have advanced our knowledge of this rare synucleinopathy. In MSA, the discovery of α-synuclein pathology and glial cytoplasmic inclusions remain the most significant findings. Families with certain types of α-synuclein mutations develop diseases that mimic MSA, and the spectrum of clinical and pathological features in these families suggests a spectrum of severity, from late-onset Parkinson’s disease to MSA. Nonetheless, controversies persist, such as the role of common α-synuclein variants in MSA and whether this disorder shares a common mechanism of spreading pathology with other protein misfolding neurodegenerative diseases. Here, we review these issues, specifically focusing on α-synuclein mutations.

In vitro anticholinesterase, antimonoamine oxidase and antioxidant properties of alkaloid extracts from kola nuts (Cola acuminata and Cola nitida)

2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Ganiyu Oboh ◽  
Ayokunle O. Ademosun ◽  
Opeyemi B. Ogunsuyi ◽  
Esther T. Oyedola ◽  
Tosin A. Olasehinde ◽  
...  
Keyword(s):  
Side Effects ◽  
Neurodegenerative Diseases ◽  
Rat Brain ◽  
Brain Homogenate ◽  
Oh Radicals ◽  
Mao Inhibitors ◽  
Alkaloid Extracts ◽  
Cola Nitida ◽  
Cola Acuminata

Abstract Background The development of cholinesterase (ChE) and monoamine oxidase (MAO) inhibitors for management of neurodegenerative diseases such as Alzheimer’s disease (AD) has come with their undesirable side effects. Hence, research for potent but natural ChE and MAO inhibitors with little or no side effects is essential. This study investigated the potentials of alkaloid extracts from two Cola species as nutraceuticals for prevention and management of AD. Methods Alkaloid extracts were obtained from two Cola species (Cola nitida [KN] and Cola acuminata [KA]) by solvent extraction method. The extracts were characterized for their alkaloid contents using gas chromatography (GC). The effects of the extracts on ChE and MAO activities were investigated in vitro. Also, the extracts’ ability to inhibit Fe2+-induced lipid peroxidation in rat brain homogenate, scavenge DPPH and OH radicals, as well as chelate Fe2+ were determined. Results GC characterization revealed the presence of augustamine and undulatine as the predominant alkaloids in the extracts. There was no significant (P > 0.05) difference in the inhibitory effects of the extracts on ChE activities. However, KA extract exhibited significantly higher (P < 0.05) MAO inhibitory effect than KN. Also, KA extract inhibited Fe2+- induced malondialdehyde (MDA) production in rat brain homogenate more significantly than KN, while there was no significant difference in DPPH and OH radicals scavenging, as well as Fe2+-chelating abilities of the extracts. Conclusions Our findings revealed that KN and KA alkaloid extracts exhibited significant effect in vitro on biological pathways that may contribute to neuroprotection for the management of neurodegenerative diseases.

scholarly journals Detection of Pathognomonic Biomarker PrPSc and the Contribution of Cell Free-Amplification Techniques to the Diagnosis of Prion Diseases

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 469
Author(s):  
Hasier Eraña ◽  
Jorge M. Charco ◽  
Ezequiel González-Miranda ◽  
Sandra García-Martínez ◽  
Rafael López-Moreno ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Prion Diseases ◽  
Immunohistochemical Analysis ◽  
Body Fluids ◽  
Detection Methods ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Prion Propagation

Transmissible spongiform encephalopathies or prion diseases are rapidly progressive neurodegenerative diseases, the clinical manifestation of which can resemble other promptly evolving neurological maladies. Therefore, the unequivocal ante-mortem diagnosis is highly challenging and was only possible by histopathological and immunohistochemical analysis of the brain at necropsy. Although surrogate biomarkers of neurological damage have become invaluable to complement clinical data and provide more accurate diagnostics at early stages, other neurodegenerative diseases show similar alterations hindering the differential diagnosis. To solve that, the detection of the pathognomonic biomarker of disease, PrPSc, the aberrantly folded isoform of the prion protein, could be used. However, the amounts in easily accessible tissues or body fluids at pre-clinical or early clinical stages are extremely low for the standard detection methods. The solution comes from the recent development of in vitro prion propagation techniques, such as Protein Misfolding Cyclic Amplification (PMCA) and Real Time-Quaking Induced Conversion (RT-QuIC), which have been already applied to detect minute amounts of PrPSc in different matrixes and make early diagnosis of prion diseases feasible in a near future. Herein, the most relevant tissues and body fluids in which PrPSc has been detected in animals and humans are being reviewed, especially those in which cell-free prion propagation systems have been used with diagnostic purposes.

scholarly journals Direct Correlation Between Ligand-Induced α-Synuclein Oligomers and Amyloid-like Fibril Growth

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Martin Nors Pedersen ◽  
Vito Foderà ◽  
Istvan Horvath ◽  
Andreas van Maarschalkerweerd ◽  
Katrine Nørgaard Toft ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Small Angle ◽  
Alpha Synuclein ◽  
X Ray ◽  
Transient Nature ◽  
X Ray Scattering ◽  
Amyloid Deposits ◽  
Potential Link ◽  
Presence And Absence

Abstract Aggregation of proteins into amyloid deposits is the hallmark of several neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. The suggestion that intermediate oligomeric species may be cytotoxic has led to intensified investigations of pre-fibrillar oligomers, which are complicated by their transient nature and low population. Here we investigate alpha-synuclein oligomers, enriched by a 2-pyridone molecule (FN075) and the conversion of oligomers into fibrils. As probed by leakage assays, the FN075 induced oligomers potently disrupt vesicles in vitro, suggesting a potential link to disease related degenerative activity. Fibrils formed in the presence and absence of FN075 are indistinguishable on microscopic and macroscopic levels. Using small angle X-ray scattering, we reveal that FN075 induced oligomers are similar, but not identical, to oligomers previously observed during alpha-synuclein fibrillation. Since the levels of FN075 induced oligomers correlate with the amounts of fibrils among different FN075:protein ratios, the oligomers appear to be on-pathway and modeling supports an ‘oligomer stacking model’ for alpha-synuclein fibril elongation.

scholarly journals Slow Progressive Accumulation of Oligodendroglial Alpha-Synuclein (α-Syn) Pathology in Synthetic α-Syn Fibril-Induced Mouse Models of Synucleinopathy

2019 ◽  
Vol 78 (10) ◽  
pp. 877-890 ◽  
Author(s):  
Norihito Uemura ◽  
Maiko T Uemura ◽  
Angela Lo ◽  
Fares Bassil ◽  
Bin Zhang ◽  
...  
Keyword(s):  
White Matter ◽  
Multiple System Atrophy ◽  
Parkinson Disease ◽  
Mouse Models ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Alpha Synuclein ◽  
Wild Type ◽  
Time Points ◽  
Progressive Accumulation

Abstract Synucleinopathies are composed of Parkinson disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Alpha-synuclein (α-Syn) forms aggregates mainly in neurons in PD and DLB, while oligodendroglial α-Syn aggregates are characteristic of MSA. Recent studies have demonstrated that injections of synthetic α-Syn preformed fibrils (PFFs) into the brains of wild-type (WT) animals induce intraneuronal α-Syn aggregates and the subsequent interneuronal transmission of α-Syn aggregates. However, injections of α-Syn PFFs or even brain lysates of patients with MSA have not been reported to induce oligodendroglial α-Syn aggregates, raising questions about the pathogenesis of oligodendroglial α-Syn aggregates in MSA. Here, we report that WT mice injected with mouse α-Syn (m-α-Syn) PFFs develop neuronal α-Syn pathology after short postinjection (PI) intervals on the scale of weeks, while oligodendroglial α-Syn pathology emerges after longer PI intervals of several months. Abundant oligodendroglial α-Syn pathology in white matter at later time points is reminiscent of MSA. Furthermore, comparison between young and aged mice injected with m-α-Syn PFFs revealed that PI intervals rather than aging correlate with oligodendroglial α-Syn aggregation. These results provide novel insights into the pathological mechanisms of oligodendroglial α-Syn aggregation in MSA.

scholarly journals Reducing C-terminal truncation mitigates synucleinopathy and neurodegeneration in a transgenic model of multiple system atrophy

2016 ◽  
Vol 113 (34) ◽  
pp. 9593-9598 ◽  
Author(s):  
Fares Bassil ◽  
Pierre-Olivier Fernagut ◽  
Erwan Bezard ◽  
Alain Pruvost ◽  
Thierry Leste-Lasserre ◽  
...  
Keyword(s):  
Multiple System Atrophy ◽  
Neurodegenerative Disorder ◽  
Disease Onset ◽  
Neuronal Cell ◽  
Alpha Synuclein ◽  
Motor Deficits ◽  
Neuroprotective Effects ◽  
Caspase 1

Multiple system atrophy (MSA) is a sporadic orphan neurodegenerative disorder. No treatment is currently available to slow down the aggressive neurodegenerative process, and patients die within a few years after disease onset. The cytopathological hallmark of MSA is the accumulation of alpha-synuclein (α-syn) aggregates in affected oligodendrocytes. Several studies point to α-syn oligomerization and aggregation as a mediator of neurotoxicity in synucleinopathies including MSA. C-terminal truncation by the inflammatory protease caspase-1 has recently been implicated in the mechanisms that promote aggregation of α-syn in vitro and in neuronal cell models of α-syn toxicity. We present here an in vivo proof of concept of the ability of the caspase-1 inhibitor prodrug VX-765 to mitigate α-syn pathology and to mediate neuroprotection in proteolipid protein α-syn (PLP-SYN) mice, a transgenic mouse model of MSA. PLP-SYN and age-matched wild-type mice were treated for a period of 11 wk with VX-765 or placebo. VX-765 prevented motor deficits in PLP-SYN mice compared with placebo controls. More importantly, VX-765 was able to limit the progressive toxicity of α-syn aggregation by reducing its load in the striatum of PLP-SYN mice. Not only did VX-765 reduce truncated α-syn, but it also decreased its monomeric and oligomeric forms. Finally, VX-765 showed neuroprotective effects by preserving tyrosine hydroxylase-positive neurons in the substantia nigra of PLP-SYN mice. In conclusion, our results suggest that VX-765, a drug that was well tolerated in a 6 wk-long phase II trial in patients with epilepsy, is a promising candidate to achieve disease modification in synucleinopathies by limiting α-syn accumulation.

Abstract P381: Understanding the Symptoms of Neurogenic Orthostatic Hypotension: Results From a Survey of Patients and Caregivers

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Lawrence A Hewitt ◽  
Charles H Adler ◽  
Daniel O Claassen ◽  
Christopher H Gibbons ◽  
Satish R Raj
Keyword(s):  
Multiple System Atrophy ◽  
Parkinson Disease ◽  
Orthostatic Hypotension ◽  
Autonomic Failure ◽  
Alpha Synuclein ◽  
Pure Autonomic Failure ◽  
Motor Symptoms ◽  
Neurogenic Orthostatic Hypotension ◽  
The Past ◽  
Increased Risk

Objective: To understand the burden and impact of symptoms of neurogenic orthostatic hypotension (nOH) on patients Background: nOH and its symptoms such as dizziness/lightheadedness are common in patients with Parkinson disease (PD) and other forms of autonomic dysfunction. Methods: An author-designed, US-based survey was conducted by Harris Poll. Eligible participants were aged ≥18 years with PD, multiple system atrophy (MSA), or pure autonomic failure and ≥1 of the following: orthostatic hypotension, nOH, low BP, OH/nOH symptoms, or were caregivers of eligible patients. Results: Most patients (90%) had a diagnosis of PD, and most caregivers (88%) cared for a patient with PD (Table 1) . Patients (34%) and caregivers (49%) reported experiencing nOH symptoms before PD or MSA motor symptoms and >40% indicated that nOH symptoms were more troublesome than motor manifestations of PD or MSA. Less than a quarter (22%) of respondents suggested symptoms were most severe in the morning; more (30%) reported a consistent severity throughout the day. Patients (40%) and caregivers (63%) reported trouble managing symptoms during the day. In the past 12 months, a fall due to nOH symptoms was reported by 57% of patients and 80% of caregivers. Conclusions: These findings suggest that nOH symptoms may predate the onset of motor symptoms in neurodegenerative conditions linked to alpha-synuclein pathology. Many respondents report nOH symptoms are the same severity through the day. Patients with nOH may have trouble managing symptoms and note an increased risk for falls.

Sign in / Sign up

Export Citation Format

Share Document