Figure 5. Detection of secreted Aβ peptides in cell culture medium in PSEN1^-/-/PSEN2^-/- MEF cells co-transfected with wild type or mutant PSEN1 and APP695ΔNL.

Immunoprecipitation of secreted Aβ in cell conditioned medium (A, C, D) and cell lysates (D). Immunoprecipitated Aβ peptides were detected by 1E8 antibody. Aβ - β-amyloid ladder. M - conditioned medium, L - cell lysate. * - a specific Aβ peptide product, which differs from Aβ42, was detected for the G382A construct. (B) Histogram shows the relative ratio of total amyloid (Aβ40 and Aβ42 or * Aβ peptide product) in PSEN1 variants calibrated to wild type Aβ40 level in 2-4 experiments. P-value significance codes: ‘***’ <0.001, ‘**’ <0.01. AD mutations C92S and M146V were used as positive controls for Aβ42 product.