Structural and functional characterization of two alpha-synuclein strains

Abstract

α-synuclein aggregation is implicated in a variety of diseases including Parkinson’s disease, dementia with Lewy bodies, pure autonomic failure and multiple system atrophy. The association of protein aggregates made of a single protein with a variety of clinical phenotypes has been explained for prion diseases by the existence of different strains that propagate through the infection pathway. Here we structurally and functionally characterize two polymorphs of α-synuclein. We present evidence that the two forms indeed fulfil the molecular criteria to be identified as two strains of α-synuclein. Specifically, we show that the two strains have different structures, levels of toxicity, and in vitro and in vivo seeding and propagation properties. Such strain differences may account for differences in disease progression in different individuals/cell types and/or types of synucleinopathies.

Immunotherapeutic Approaches Targeting Amyloid-β, α-Synuclein, and Tau for the Treatment of Neurodegenerative Disorders

“…scFvs retain antigen-binding properties and can be easily screened for desired affinities using phage display methodology. Using this type of approach, scFvs that detect individual conformational species of α-syn have been identified [151][152][153], and could be potentially used to discriminate among protein conformers for the differential treatment of synucleinopathies or for diagnostic purposes [154]. Moreover, scFvs can be further modified to increase BBB penetrability and facilitate the clearance of α-syn.…”

Implantable amyloid hydrogels for promoting stem cell differentiation to neurons

“…In one condition, phosphate buffer was placed on top of the gel surface (condition A), and the gel was then incubated up to 21 days. To mimic the degradation of the gel in vivo, the gel was further mixed with 3.8 μg ml − 1 proteinase K, an enzyme most frequently used for the non-specific degradation of proteins and amyloids 23,24 (condition B), and incubated for 21 days. After 7 and 21 days of incubation, 2% v/v degraded gel products from both conditions A and B were added to WT α-Syn, and aggregation was monitored via ThT fluorescence (Figures 3c and d).…”

“…In one condition, phosphate buffer was placed on top of the gel surface (condition A) and incubated for up to 21 days. To mimic the possible degradation of the gel in vivo, the gel was mixed with 3.8 μg ml − 1 proteinase K (the enzyme most frequently used for the nonspecific degradation of protein and amyloids 23,24 ) and incubated for 21 days. After 7 and 21 days of incubation, 150 μl of soluble α-Syn was mixed with 3 μl solution of phosphate buffer placed on the top (condition A) to achieve a 2% v/v concentration of degraded gel.…”

Assemblages d’alpha-synucléine

“…Ils ont ensuite étudié la résistance à la digestion par la protéinase K de la protéine provenant des cerveaux de rat inoculés avec les formes fibre et ruban. Il avait précédemment été montré, in vitro, que la forme fibre présentait une plus grande résistance à la digestion par la protéinase K par rapport à la forme ruban [8]. L'alpha-synucléine extraite du cerveau de rats inoculés avec les…”

“…L'alpha-synucléine humaine d'origine recombinante peut exister sous forme de fibres ou de rubans En 2013, l'équipe de Ronald Melki est parvenue à produire expérimentale-ment deux types de structures d'alpha-synucléine à partir d'alpha-synucléine humaine recombinante sauvage : l'une en forme de rubans et l'autre en forme de fibres [8]. Ces deux formes structurales ont été différenciées par un ensemble de propriétés, incluant leurs caractéristiques physiques (temps de polymérisation, diffraction aux rayons X, etc.…”