Cell Adhesion Molecule Protocadherin-γC5 Ameliorates Aβ Plaque Pathogenesis by Modulating Astrocyte Function in Alzheimer's Disease

Accumulation of astrocytes around β-amyloid (Aβ) plaques is one of the earliest neuropathological changes in Alzheimer's disease (AD), but the underlying mechanisms and significance remain unclear. Cell adhesion molecule protocadherin-γC5 (Pcdh-γC5) has been reported to implicate in AD. Here, we find elevated expression levels of Pcdh-γC5 in the brain of 5×FAD mice and Aβ-treated astrocytes and further reveal that Pcdh-γC5 deficiency leads to exacerbated Aβ deposition in 5×FAD mice. Deletion of Pcdh-γC5 impairs astrocyte migration, astrocytic response to Aβ signaling, and Aβ phagocytosis in both cultured astrocytes in vitro and 5×FAD mice in vivo. Both male and female mice were used in this study. Our findings support a model in which increased expression level of Pcdh-γC5 promotes astrocyte migration in response to Aβ signaling and engulfment and phagocytosis of neurotoxic Aβ plaques, therefore exerting a critical neuroprotective function in AD.