Figure 8. Expression of the APP-3R mutant leads to an increase in secreted Aβ.

a and b) Mouse neurons were infected with lentiviruses expressing human APP_WT^GFP and APP_3R^GFP at DIV 7. At DIV 14, secreted APP metabolite sAPPα was analyzed by SDS-page and Western blot (in a and b), while secreted APP metabolite sAPPβ was measured by ELISA of culture media (in c). Synaptotagmin was used as an equal loading marker. The graphs show the quantification of full length APP normalized to synaptotagmin (in a) and the quantification of metabolites sAPPα (in b) and sAPPβ levels (in c) as a ratio of metabolite/full length APP^GFP. Values denote means ± SEM (n=8).

d and e) Bar diagram showing the quantification of human Aβ40 (in d) and Aβ42 (in e) peptide levels measured by ELISA in neuronal media after infection of neurons with lentiviruses expressing human APP_WT^GFP or APP_3R^GFP. Aβ levels were normalized to the cell lysate total protein and results are expressed as % of APP_WT^GFP. Values denote means ± SEM (n=13). **, denotes P values < 0.01 from a Student's t-test.