Poster Presentations

Session Title: Neurodevelopment and Neurodegeneration
Presentation Date: Friday, March 14 – Saturday, March 15, 2009

AMYLOID ß PRODUCTION IS IMPORTANT FOR CELL VIABILITY AND NEURITE OUTGROWTH

R. Sayer¹, T.L. Kerrigan¹, C. Peers², H.A. Pearson^1
1University of Leeds, Institute of Membrane and Systems Biology, Leeds, United Kingdom, ²University of Leeds, Division of Cardiovascular and Neuronal Remodelling, Leeds, United Kingdom

Elevated levels of the amyloid beta (Aß) peptide is one of the key pathological hallmarks of Alzheimer's disease. Aß is also found in the cerebrospinal fluid of healthy individuals suggesting a physiological role for Aß peptide. The aim of this study was to determine the effects on cell growth and viability of inhibiting Aß production.
SH-SY5Y cells and reaggregate cultures of cerebellar granule neurones (CGN) were treated with γ secretase inhibitors (10µM) for 24 hrs, and the cell viability, caspase 3/7 activity or neurite outgrowth length determined. Small interfering RNA (shiRNA) duplexes designed against BACE-1 were transfected into SH-SY5Y cells.
SH-SY5Y viability was reduced caspase 3/7 activity increased following treatment with γI a selective inhibitor of Aß_1-40 (44±3% of control for cell viability) (353±9% of control for caspase 3/7), and γ IV, an inhibitor of both the Aß_1-40 and Aß₄₂ peptides (54±9 % of control for cell viability) (218±13% of control for caspase 3/7). γ VI, the selective Aß₄₂ inhibitor had no effect on cell viability (102±9% of control) or caspase 3/7 activity (119±28% of control) (n=4). BACE 1 shRNAi produced a decrease in cell viability (0.011±0.001 AU/mg protein) compared to controls (0.020±0.002 AU/mg protein) and an increase in caspase 3/7 activity (n=4). Treatment with either 10mM γI or γIV significantly reduced neurite outgrowth in CGN reaggregates (n=3). However γVI was without effect. (n=3).
This study provides evidence that the Aß_1-40 peptide is important in neurite outgrowth and the regulation of cell survival.