Glycobiology of mouse cellular prion protein during neuronal ageing

Abstract

Prion diseases, characterised by the conformational conversion of a host-encoded prion protein (PrPC) to the scrapie isoform (PrPSc), are fatal age-related neurological disorders. Accumulating evidence suggests that the highly conserved N-linked glycans on PrPC highlight the prion disease phenotype. In this study, three lines of evidence from PrPC glycan profiling suggest that ageing and prion diseases are closely related. Firstly, Western blotting showed enhanced expression of underglycosylated full length PrPC and N-terminally truncated PrPC with increased age. Secondly, lectin-binding assay revealed increased complex sugar formation on ageing full length PrPC. Thirdly, simplification of the glycosylation process was observed on ageing truncated PrPC suggesting possible ER retention and consequent aggregation. Taken together, these results suggest that age-related changes in PrPC glycosylation may render certain pools of glycosylated PrPC more susceptible to PrPSc conversion than others, and strengthen the involvement of PrP glycosylation in prion disease development.