Albumin-Blunted Deleterious Effect of Amyloid-β by Preventing the Internalization of the Peptide into Neurons

Abstract

Amyloid-β (Aβ) is the main component of senile plaques, one of the hallmarks of Alzheimer's disease. Our results showed that Aβ_25-35 decreased neuronal viability while it increased generation of reactive oxygen species (ROS). Under these circumstances, albumin (BSA) prevented ROS production and neuronal death in a dose- and time-dependent manner. In addition, BSA partially prevented the decrease in the expression of GAP-43, MAP-2, and tubulin, and the phosphorylation of tau protein caused by Aβ, suggesting that BSA protects against the loss of plasticity caused by the peptide. Our findings suggest that BSA exerts its protective effect by binding to Aβ in an equimolecular way, which prevents heterodimer (Aβ-BSA) entry into neurons. In fact, BSA prevented Aβ internalization, as shown by confocal immunocytochemistry, suggesting that BSA causes its protective effect by sequestrating Aβ, which cannot reach its intracellular targets. This is consistent with the idea that Aβ must enter neurons to exert its deleterious effects.