Age-dependent changes in Wnt signaling components and synapse number are differentially affected between brain regions

Wnt signaling plays an important role in adult brain function, and its dysregulation has been implicated in functional decline during aging as well as in some neurodegenerative diseases, such as Alzheimer's disease. In the adult brain, the Wnt pathway contributes to synapse formation and maintenance, axonal remodeling, and dendrite outgrowth. Recent findings indicate a downregulation of Wnt signaling in the aged brain in different models, but it has not been associated with changes in the number and structure of central synapses. The expression and distribution of Wnt components in different brain regions may vary with age, which may have important implications for brain homeostasis manifesting as different behavioral alterations. Thus, in the present work, we analyzed the expression levels and protein content of different molecules of the Wnt pathway in young and aged rats in the cerebral cortex, hippocampus and cerebellum and discussed their correlation with changes in synaptic number and morphology.