Alpha Synuclein Pre-Formed Fibrils (PFFs)

Alpha Synuclein Pre-Formed Fibrils (PFFs) Background

Alpha-synuclein (αSyn) is a soluble presynaptic localization protein that is used in conjunction with proteins such as N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes and cysteine string protein alpha (CSPα) chaperone proteins to promote repopulation of the vesicle pool and release of vesicles from the active zone. Under pathological conditions, this soluble protein undergoes multiple post-translational modifications and forms higher-order oligomers and fibrillar species, resulting in conformationally and biologically distinct aggregates. These inclusions are termed Lewy bodies (LB) and Lewy neuropil (LN) in Parkinson's disease (PD), PD with dementia (PDD) and Lewy body dementia (DLB), or glial cytoplasmic inclusions (GCI) in multisystem atrophy. In addition, neurodegenerative diseases with αSyn pathology are known as synucleinopathies. αSyn PFF is a purified prion-like, self-templating, and propagatable misfolded αSyn aggregate that induces Lewy body-like inclusions and cellular dysfunction in both in vitro and in vivo models.

Fig. 2 Schematic summary of αSyn inclusion formation, dendritic spine dysfunction, and neuronal loss.
(Wu Q, et al., 2019)

In the presence of exogenous αSyn PFFs, soluble endogenous αSyn monomers are recruited into aggregates (1). These aggregates are distributed in the dendritic spines, induced spine shrinkage, and synaptic deficits (2). Long-term incubations lead to neurodegeneration in inclusion-bearing neurons (3).

Applications for Alpha-Synuclein Protofibrils

• With αSyn PFF, we can study pathological transmission mechanisms between neurons and across neuronal connections in vivo. In addition, we can study the motor and behavioral consequences of Syn deposits accumulation in different brain structures.
• αSyn PFF to study neuronal uptake of misfolded αSyn.
• αSyn PFF used in neuronal cultures induces the accumulation of insoluble intracellular deposits that mature over time, increasing their similarity to Lewy bodies.
• Application of αSyn PFF to neurons cultured in microfluidic chambers allows intercellular transport in pathological aggregates. This demonstrates the efficacy of antibodies targeting extracellular αSyn or putative αSyn receptors in blocking this process.
• The in vivo αSyn PFF model will facilitate the development of PET tracers for the longitudinal assessment of αSyn pathology in PD patients. Once developed, this imaging tool will be very useful for monitoring clinical trials and early disease diagnosis.