Internalization of α-synuclein oligomers into SH-SY5Y cells

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Misfolded alpha-synuclein (α-synuclein) aggregates are key pathological hallmarks of Parkinson's disease.
• Small α-synuclein oligomers are implicated as neurotoxic agents, exhibiting prion-like propagation of misfolding.
• Cellular uptake mechanisms for α-synuclein oligomers, particularly size-dependent variations, remain incompletely understood.

Purpose of the Study:

• To investigate how the size of α-synuclein oligomers influences their internalization into live neuronal cells.
• To compare the uptake of α-synuclein monomers, dimers, and tetramers in SH-SY5Y cells.
• To elucidate the endocytic pathways involved in α-synuclein oligomer internalization.

Main Methods:

• Utilized fluorescently labeled α-synuclein monomers, engineered dimers, and tetramers for uptake studies.
• Employed live SH-SY5Y neuroblastoma cells for cellular internalization experiments.
• Performed co-localization studies with endosomal and lysosomal markers.
• Applied Pitstop inhibitor to assess the role of clathrin-mediated endocytosis.

Main Results:

• α-Synuclein constructs (monomers, dimers, tetramers) were primarily internalized via endocytosis.
• Oligomer size exhibited minimal influence on the internalization pathway, regardless of whether constructs were applied individually or combined.
• Most internalized α-synuclein localized within endocytic compartments, suggesting degradation.
• Clathrin-mediated endocytosis was identified as the predominant pathway for oligomer uptake.

Conclusions:

• Cellular uptake of α-synuclein oligomers is predominantly mediated by endocytosis, with clathrin-mediated endocytosis being a major route.
• The size of α-synuclein oligomers does not significantly alter their endocytic uptake mechanism or pathway.
• These findings contribute to understanding the cellular entry of pathogenic α-synuclein species in Parkinson's disease.