Objective: We determined whether increased expression of DAT have an impact on the uptake of α-synuclein (αS).

Background: The endocytosis of dopamine transporter (DAT) controls the re-uptake of dopamine, thereby maintaining dopaminergic tone in the nervous systems. The carboxyl-terminal region of DAT binds to the non-Aβ amyloid component of αS, suggesting a possible role of DAT in the uptake of extracellular αS.

Methods: Human embryonic kidney 293T (HEK293T) cells were transiently transfected with human DAT expression plasmid, followed by the incubation with either monomer or fibrillar form of recombinant human αS for 48 hours. In some experiments, the cells were pretreated with sertraline, a known inhibitor of dynamin dependent endocytosis. Internalized αS was detected by Western blotting and immunocytochemistry.

Results: After exposure to recombinant αS, both monomer and fibrillar αS were incorporated into the cells in a dose-dependent manner, which was further augmented by the over-expression of DAT. Intriguingly, the incorporation of fibrils rather than monomer αS was markedly suppressed in the presence of sertraline in mockas well as DAT-transfected cells. Furthermore, exposure to fibrillar forms of αS resulted in a dramatic redistribution of DAT from cell surface to cytosolic compartment.

Conclusions: DAT promoted the uptake of monomeric as well as fibrillar forms of αS at the surface of the cells. This finding might suggest the possible role of DAT on cell-type specific pathological consequences in Parkinson’s disease and related disorders.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/cell-surface-expression-of-dopamine-transporter-facilitates-the-uptake-of-synuclein/