Modulation of Amyloid-β peptide aggregation and neurotoxicity in Alzheimer's disease

Guivernau Almazán, Biuse

Modulation of Amyloid-β peptide aggregation and neurotoxicity in Alzheimer's disease

Document Type

Doctoral thesis
Published Version

Author

Guivernau Almazán, Biuse

Director

Muñoz López, Francisco José

Publication Date

2016-06-10

Pages

237 p.

Citation

Guivernau Almazán, B. Modulation of Amyloid-β peptide aggregation and neurotoxicity in Alzheimer's disease. Universitat Pompeu Fabra; 2016. handle: http://hdl.handle.net/10803/585932

This citation was generated automatically.

Doctoral program

Programa de doctorat en Biomedicina

Abstract

Aggregation of the amyloid-β (Aβ) peptide to form oligomers and amyloid fibrils is a central event in the pathogenesis of Alzheimer’s disease (AD). This thesis aims to provide a better understanding of Aβ toxicity and the impact of changes in Aβ aggregation, both relevant to AD. We have found that Aβ nitrotyrosination inhibits fibril formation, which favours the stabilization of small oligomers. We show that nitro-Aβ oligomers strongly bind to dendrites, altering N-methyl-D-aspartate receptor (NMDAR) physiological function and leading to neuronal dysfunction and cell death. Furthermore, we propose a model for Aβ fibril assembly, according to which fibril elongation is interrupted upon nitrotyrosination, due to the destabilization of interprotofibrillar contacts. Additionally, using a genome-wide screen in Saccharomyces cerevisiae, we have identified novel modulators of Aβ toxicity that are potential targets for the development of new AD therapeutic approaches.
L’agregació del pèptid b-amiloide (Aβ) en forma d’oligòmers i fibres és un esdeveniment central en la patogènesi de la malaltia d’Alzheimer. Aquesta tesi pretén aprofundir en els coneixements actuals sobre la toxicitat causada per l’Aβ així com en l’impacte que tenen els canvis en l’agregació d’aquest, tots dos rellevants per la malaltia d’Alzheimer. Els nostres resultats indiquen que la nitrotirosinació de l’Aβ inhibeix la formació de fibres, afavorint l’estabilització d’oligòmers. Demostrem que els oligòmers d’Aβ nitrat s’uneixen a les dendrites, alterant la funció fisiològica dels receptors d’N-metil- D-aspartat (NMDAR) i provocant disfuncions neuronals i la mort cel·lular. A més, proposem un model d’assemblatge per a les fibres d’Aβ, segons el qual la nitrotirosinació interromp l’elongació de la fibra a causa de la desestabilització dels contactes entre protofibres. Addicionalment, utilitzant un cribratge genòmic en Saccharomyces cerevisiae, hem identificat nous moduladors de la toxicitat causada per Aβ, que podrien ser clau per al desenvolupament de noves estratègies terapèutiques de la malaltia Alzheimer.