CRMP2 Hyperphosphorylation is Characteristic of Alzheimer's Disease and not a Feature Common to Other Neurodegenerative Diseases

Article type: Research Article

Authors: Williamson, Ritchie^a | van Aalten, Lidy^a | Mann, David M.A.^b | Platt, Bettina^c | Plattner, Florian^d | Bedford, Lynn^e | Mayer, John^e | Howlett, David^f | Usardi, Alessia^g | Sutherland, Calum^a | Cole, Adam R.^{a; *}

Affiliations: [a] Biomedical Research Institute, University of Dundee, Ninewells Hospital, Dundee, Scotland, UK | [b] Neurodegeneration and Mental Health Research Group, University of Manchester, Greater Manchester Neuroscience Centre, Hope Hospital, Salford, UK | [c] School of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK | [d] Institute of Neurology, University College London, London, UK | [e] School of Biomedical Sciences and School of Molecular Medical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK | [f] GlaxoSmithKline, Harlow, Essex, UK | [g] Institute of Psychiatry, Kings College London, London, UK

Correspondence: [*] Correspondence to: Dr. Adam R. Cole, Garvan Institute of Medical Research, 384 Victoria St. Darlinghurst, Sydney, Australia. Tel.: +61 2 9295 8289; Fax: +61 3 9296 8100; E-mail: a.cole@garvan.org.au.

Abstract: Collapsin response mediator protein 2 (CRMP2) is an abundant brain-enriched protein that regulates neurite outgrowth. It is phosphorylated by Cdk5 and GSK3, and these modifications are abnormally high in the brains of Alzheimer's disease (AD) patients. Increased phosphorylation of CRMP2 is also apparent in mouse models of AD that express mutated AβPP and PSEN1, but not AβPP or tau alone, where it is detectable before the appearance of amyloid plaques and neurofibrillary tangles, suggesting it is an early event in AD pathogenesis. Here, we have extended these observations by showing that CRMP2 is not hyperphosphorylated in mice overexpressing mutated PSEN1 alone, or in cultured neurons treated with soluble, oligomeric Aβ42 peptide. Similarly, CRMP2 phosphorylation was not increased in a mouse model of severe neurodegeneration (PMSC-1 knockout) or in cultured neurons subjected to neurotoxic concentrations of NMDA or staurosporine. Most interestingly, CRMP2 phosphorylation was not increased in frontal cortex from patients with frontotemporal lobar degeneration associated with mutations in MAPT or with Pick bodies. Together, these observations are consistent with the hypothesis that abnormal phosphorylation of CRMP2 is specific to AD and occurs downstream of excessive processing of AβPP, but that neither excessive Aβ42 peptide nor neurotoxicity alone are sufficient to promote hyperphosphorylation.

Keywords: Alzheimer's disease, Cdk5, CRMP2, GSK3, neurodegeneration, phosphorylation

DOI: 10.3233/JAD-2011-110617

Journal: Journal of Alzheimer's Disease, vol. 27, no. 3, pp. 615-625, 2011