O1‐05‐03: Preventive anti‐Aß passive immunization using a subcutaneous cellular implant lowers brain amyloid burden and tau pathology

CRMP-2 regulates disruption from the kinesin-1 axonal transport motor protein in Alzheimer’s disease. Methods:Post-mortem temporal and frontal lobe cortical AD (n1⁄48 patients), multiple sclerosis (MS) (n1⁄45), Huntington disease (HD) (n1⁄44), frontotemporal dementia (FTD) (n1⁄49) and non-neurological disease control brain lysates (n1⁄412) were analysed by immunoprecipitation, western blotting and immunostaining to identify CRMP-2 phosphorylation and inhibition of CRMP-2 binding to kinesin and tubulin. Coronal brain sections from Tg2576 mice (n1⁄412) were also immunostained for phospho-Thr555 CRMP-2 and data compared directly with sections from wild type brains (n1⁄44). SH-SY5Y cells were also transfected with CRMP-2 phosphorylation-mutant constructs (n1⁄45), treated with Abeta140 and Abeta1-42 (0.5, 1.0 and 10uM for 24h), to define which Abeta-mediated kinase may initiate phospho-CRMP-2-dependent neurite abnormalities. Results: We found enhanced Abdependent phosphorylation of CRMP-2 at the T555 site and reduced CRMP-2 association with kinesin-1, while the overexpression of an unphosphorylatable form of CRMP-2 in neurons promoted the re-establishment of CRMP-2-kinesin association and axon elongation. Additionally, in the transgenic Tg2576 mouse model of familial AD (FAD), that carries the Swedish mutation in amyloid precursor protein (APP) enhancing Ab overproduction, we found substantial staining with pT555CRMP-2 and axonal dystrophy. Consistent with these findings, brain lysates from AD patients demonstrated phosphorylation of CRMP-2 at T555 site and dissociation of CRMP-2 from kinesin-1. Conclusions: These data suggest that Ab-dependent phosphorylation of CRMP-2 at the T555 site may directly impair anterograde axonal transport and is sufficient to lead to axonal defects.