Endocytic pathways mediating oligomeric Aβ42 neurotoxicity

Background: One pathological hallmark of Alzheimer’s disease (AD) is amyloid plaques, composed primarily of amyloid-β peptide (Aβ). Over-production or diminished clearance of the 42 amino acid form of Aβ (Aβ42) in the brain leads to accumulation of soluble Aβ and plaque formation. Soluble oligomeric Aβ (oAβ) has recently emerged to be as a likely proximal cause of AD. Results: Here we demonstrate that endocytosis is critical in mediating oAβ42-induced neurotoxicity and intraneuronal accumulation of Aβ. Inhibition of clathrin function either with a pharmacological inhibitor, knock-down of clathrin heavy chain expression, or expression of the dominant-negative mutant of clathrin-assembly protein AP180 did not block oAβ42-induced neurotoxicity or intraneuronal accumulation of Aβ. However, inhibition of dynamin and RhoA by expression of dominant negative mutants, reduced neurotoxicity and intraneuronal Aβ accumulation. Pharmacologic inhibition of the dynamin-mediated endocytic pathway by genistein also reduced neurotoxicity. Conclusions: These data suggest that dynamin-mediated and RhoA-regulated endocytosis are integral steps for oligomeric Aβ42-induced neurotoxicity and intraneuronal Aβ accumulation.