Amyloid precursor protein is enriched in radial glia: Implications for neuronal development

The amyloid precursor protein (APP) is a transmembrane glycoprotein and the source of the amyloid that accumulates in brains of individuals with Alzheimer's and other neurodegenerative diseases. Although its function is unknown, previous in vitro studies indicate that APP can facilitate neuronal cell adhesion and neuronal survival. If APP has a similar function in vivo, it should be expressed in fetal brain. To investigate this possibility, the present study determined the cellular distribution of APP in fetal and postnatal mouse brain. Immunocytochemistry and confocal microscopy detected abundant APP immunoreactivity in radial glial cells in fetal and early postnatal mouse brain. In mature mouse brain, APP was detected in neuronal perikarya and dendrites but not in astrocytes. These results support a functional role for APP during radial glia-mediated neuronal histogenesis.