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Title: Investigating the effects of the Alzheimer's disease-associated amyloid β-peptide on intracellular calcium homeostasis
Author: Allan, Laura Elizabeth
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2010
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I investigated the effects of Aβ42 on the Ca2+ signalling capacity of human neuroblastoma SH-SY5Y cells and primary hippocampal cultures. I developed an in vitro model system of dissociated hippocampal neurons and glial cells in order to reflect as closely as possible the mature hippocampus. Extensive characterisation of the culture revealed that functional neuronal networks were established by day in vitro 11, as demonstrated by the occurrence of spontaneous oscillations in both membrane potential and intracellular Ca2+ levels. Neurons exhibited functional ionotropic and metabotropic signalling systems which, in turn, rendered them sensitive to cell death induced by excitotoxic stimuli. Samples of synthetic Aβ42 were prepared according to two published protocols. One protocol produced Aβ42 samples which exhibited highly dynamic aggregation kinetics, the other produced homogeneous Aβ42 oligomers which were stable in their conformational state for up to 24 hours. While both Aβ42 preparations impaired cell viability following 24-hour treatment, only Aβ42 oligomers elicited robust Ca2+ responses following their extracellular application to cells. Aβ42 oligomers elicited distinct but different effects on the Ca2+ signalling capacity of SH-SY5Y cells and primary hippocampal neurons, respectively. in SH-SY5Y cells, Aβ42 oligomers acted to deplete the content of the intracellular ER Ca2+ store, in part through InsP3 receptors and in part through an as yet unidentified leak pathway. In primary hippocampal neurons, the application of Aβ42 oligomers resulted in a sustained and elevated increase in intracellular Ca2+ concentrations. It is postulated that these early cellular events, although distinct, will ultimately converge on a common pathway resulting in dysregulation of Ca2+ homeostasis and cell death. Thus, the findings of this thesis support the mounting body of evidence implicating the role of Ca2+ dysregulation in mediating the neurotoxic effects of Aβ42 oligomers.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral