Acetylcholinesterase-amyloid-beta-peptide interaction and Wnt signaling involvement in Abeta neurotoxicity.

Previous studies have indicated that acetylcholinesterase (AChE) promotes amyloid-beta-peptide (Abeta) fibril formation and AChE-Abeta complexes increase Abeta-dependent neurotoxicity. Here we present evidence for the: i) identification of the AChE motif that promotes amyloid formation, ii) in vivo effect of AChE on brain plaque formation, and iii) connection between AChE-Abeta neurotoxicity and the Wnt signal transduction pathway. Computer modeling, stereotaxic infusions and cell biological techniques were used to study the above problems. Results indicated that a 3.4 kDa AChE peptide promotes Abeta fibril formation. AChE infusion into rat hippocampus determines the appearance of anti-Abeta and thioflavine-S positive plaques, and AChE-Abeta toxicity on hippocampal cultures was blocked by lithium, an activator of the Wnt cascade. We suggest that AChE-Abeta/Abeta dependent neurotoxicity may result in loss of function of Wnt signaling components, and open the possibility that lithium may be considered as a candidate for therapeutic intervention in Alzheimer's disease pathology.