The cellular prion protein and its role in Alzheimer disease

Abstract

The cellular prion protein (PrPC) is a membrane-bound glycoprotein especially abundant in the central nervous system (CNS). The scrapie prion protein (PrPSc, also termed prions) is responsible of transmissible spongiform encephalopathies (TSE), a group of neurodegenerative diseases which affect humans and other mammal species, although the presence of PrPC is needed for the establishment and further evolution of prions. The present work compares the expression and localization of PrPC between healthy human brains and those suffering from Alzheimer disease (AD). In both situations we have observed a rostrocaudal decrease in the amount of PrPC within the CNS, both by immunoblotting and immunohistochemistry techniques. PrPC is higher expressed in our control brains than in AD cases. There was a neuronal loss and astogliosis in our AD cases. There was a tendency of a lesser expression of PrPC in AD cases than in healthy ones. And in AD cases, the intensity of the expression of the unglycosylated band is higher than the di- and monoglycosylated bands. With regards to amyloid plaques, those present in AD cases were positively labeled for PrPC, a result which is further supported by the presence of PrPC in the amyloid plaques of a transgenic line of mice mimicking AD. The work was done according to Helsinki Declaration of 1975, and approved by the Ethics Committee of the Faculty of Medicine of the University of Navarre.