The phosphorylation of Hsp20 enhances its association with amyloid-β to increase protection against neuronal cell death

Cameron, R. T., Quinn, S. D. , Cairns, L. S., MacLeod, R., Samuel, I. D.W., Smith, B. O., Penedo, J. C. and Baillie, G. S. (2014) The phosphorylation of Hsp20 enhances its association with amyloid-β to increase protection against neuronal cell death. Molecular and Cellular Neuroscience, 61, pp. 46-55. (doi:10.1016/j.mcn.2014.05.002) (PMID:24859569) (PMCID:PMC4148482)

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Abstract

Up-regulation of Hsp20 protein levels in response to amyloid fibril formation is considered a key protective response against the onset of Alzheimer's disease (AD). Indeed, the physical interaction between Hsp20 and Aβ is known to prevent Aβ oligomerisation and protects neuronal cells from Aβ mediated toxicity, however, details of the molecular mechanism and regulatory cell signalling events behind this process have remained elusive. Using both conventional MTT end-point assays and novel real time measurement of cell impedance, we show that Hsp20 protects human neuroblastoma SH-SY5Y cells from the neurotoxic effects of Aβ. In an attempt to provide a mechanism for the neuroprotection afforded by Hsp20, we used peptide array, co-immunoprecipitation analysis and NMR techniques to map the interaction between Hsp20 and Aβ and report a binding mode where Hsp20 binds adjacent to the oligomerisation domain of Aβ, preventing aggregation. The Hsp20/Aβ interaction is enhanced by Hsp20 phosphorylation, which serves to increase association with low molecular weight Aβ species and decrease the effective concentration of Hsp20 required to disrupt the formation of amyloid oligomers. Finally, using a novel fluorescent assay for the real time evaluation of morphology-specific Aβ aggregation, we show that phospho-dependency of this effect is more pronounced for fibrils than for globular Aβ forms and that 25mers corresponding to the Hsp20 N-terminal can be used as Aβ aggregate inhibitors. Our report is the first to provide a molecular model for the Hsp20/Aβ complex and the first to suggest that modulation of the cAMP/cGMP pathways could be a novel route to enhance Hsp20-mediated attenuation of Aβ fibril neurotoxicity.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Quinn, Dr Steven and Baillie, Professor George and MacLeod, Miss Ruth and Cameron, Mr Ryan and Smith, Dr Brian
Authors: Cameron, R. T., Quinn, S. D., Cairns, L. S., MacLeod, R., Samuel, I. D.W., Smith, B. O., Penedo, J. C., and Baillie, G. S.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Science and Engineering > School of Chemistry
Journal Name:Molecular and Cellular Neuroscience
Publisher:Elsevier Inc.
ISSN:1044-7431
ISSN (Online):1095-9327
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in Molecular and Cellular Neuroscience 61:46-55
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
500151Doctoral Training Grant 2009-15Timothy PalmerBiotechnology and Biological Sciences Research Council (BBSRC)BB/F016735/1RI CARDIOVASCULAR & MEDICAL SCIENCES