Altered prion protein glycosylation in the aging mouse brain

The normal cellular prion protein (PrPC) is a glycoprotein with two highly conserved potential N-linked glycosylation sites. All prion diseases, whether inherited, infectious or sporadic, are believed to share the same pathogenic mechanism that is based on the conversion of the normal cellular prion protein (PrPC) to the pathogenic scrapie prion protein (PrPSc). However, the clinical and histopathological presentations of prion diseases are heterogeneous, depending not only on the strains of PrPSc but also on the mechanism of diseases, such as age-related sporadic vs. infectious prion diseases. Accumulated evidence suggests that N-linked glycans on PrPC are important in disease phenotype. A better understanding of the nature of the N-linked glycans on PrPC during the normal aging process may provide new insights into the roles that N-linked glycans play in the pathogenesis of prion diseases. By using a panel of 19 lectins in an antibody-lectin enzyme-linked immunosorbent assay (ELISA), we found that the lectin binding profiles of PrPC alter significantly during aging. There is an increasing prevalence of complex oligosaccharides on the aging PrPC, which are features of PrPSc. Taken together, this study suggests a link between the glycosylation patterns on PrPC during aging and PrPSc.