The role of Wnt signaling in neuronal dysfunction in Alzheimer's Disease

Recent evidence supports a neuroprotective role for Wnt signaling in neurodegenerative disorders such as Alzheimer's Disease (AD). In fact, a relationship between amyloid-beta-peptide (A beta)-induced neurotoxicity and a decrease in the cytoplasmic levels of beta-catenin has been observed. Apparently A beta binds to the extracellular cysteine-rich domain of the Frizzled receptor (Fz) inhibiting Wnt/beta-catenin signaling. Cross-talk with other signaling cascades that regulate Wnt/beta-catenin signaling, including the activation of M-1 muscarinic receptor and PKC, the use of Ibuprofen-ChE bi-functional compounds, PPAR alpha, gamma agonists, nicotine and some antioxidants, results in neuroprotection against A beta. These studies indicate that a sustained loss of Wnt signaling function may be involved in the A beta-dependent neurodegeneration observed in Alzheimer's brain. In conclusion the activation of the Wnt signaling pathway could be proposed as a therapeutic target for the treatment of AD.