ABSTRACT
AIMS: Alzheimer's disease (AD) is characterized by deposition of the amyloid beta (Aß) peptide in brain parenchyma and vasculature. Several proteins co-deposit with Aß, including heparan sulphate proteoglycans (HSPG). HSPG have been suggested to contribute to Aß aggregation and deposition, and may influence plaque formation and persistence by stimulating Aß fibrillization and by protecting Aß against degradation. Mouse models for AD, expressing the human amyloid precursor protein (APP), produce Aß deposits similar to humans. These models may be used to study disease pathology and to develop new therapeutic interventions. We aimed to investigate whether co-deposition of HSPG in AD brains can be replicated in the APPswe/PS1dE9 mouse model for AD and if a temporal association of HSPG with Aß exists. METHODS: We studied the co-deposition of several HSPG and of the glycosaminoglycan side chains of HSPG in the APPswe/PS1dE9 model at different ages by immunohistochemistry. RESULTS: We found that, although APPswe/PS1dE9 mice did develop severe Aß pathology with age, co-deposition of HS glycosaminoglycan chains and the various HSPG (agrin, perlecan and glypican-1) was scarce (<10-30% of the Aß deposits were stained). CONCLUSIONS: Our data suggest that the molecular composition of Aß deposits in the APPswe/PS1dE9 mouse, with respect to the several HSPG investigated in this study, does not accurately reflect the human situation. The near absence of HSPG in Aß deposits in this transgenic mouse model may, in turn, hinder the translation of preclinical intervention studies from mice to men.
