Emerging roles of Wnts in the adult nervous system.

The roles of the Wnt signalling pathway in several developmental processes, including synaptic differentiation, are well characterized. The expression of Wnt ligands and Wnt signalling components in the mature mammalian CNS suggests that this pathway might also play a part in synaptic maintenance and function. In fact, Wnts have a crucial role in synaptic physiology, as they modulate the synaptic vesicle cycle, the trafficking of neurotransmitter receptors and the interaction of these receptors with scaffold proteins in postsynaptic regions. In addition, Wnts participate in adult neurogenesis and protect excitatory synaptic terminals from amyloid-beta oligomer toxicity. Here, the latest insights into the function of Wnt signalling in the adult nervous system and therapeutic opportunities for neurodegenerative diseases such as Alzheimer's and Parkinson's disease are discussed.