Plasmalogens Inhibit APP Processing by Directly Affecting γ-Secretase Activity in Alzheimer’s Disease
Figure 4
Determination of γ-secretase activity in the presence of PC-PL 18 : 1, PC-PL 20 : 4, PC-PL 22 : 6, and PE-PL 22 : 6. (a) Influence on γ-secretase activity in purified membranes of human SH-SY5Y cells. Purified membranes of SH-SY5Y cell were incubated with PC-PL 18 : 1, 20 : 4, 22 : 6, or PE-PL 22 : 6 and the corresponding phospholipids (100 μM), and γ-secretase activity was determined by a fluorometric assay. (b) Influence on γ-secretase activity ex vivo in purified membranes of mouse brains. Purified mouse brain membranes were incubated with PC-PL 18 : 1 and PC-PL 20 : 4 and the corresponding phospholipids (100 μM), and γ-secretase activity was determined. (c) Cultured SH-SY5Y cells were incubated with PC-PL 18 : 1 and PC-PL 20 : 4 and the corresponding phospholipids PC 18 : 1 and PC 20 : 4 for 24 hours in a final concentration of 100 μM. Membranes of incubated SH-SY5Y cells were prepared and γ-secretase activity was determined with a fluorometric assay. (a, b, c) Representative kinetics are shown for PC-PL 18 : 1 and PC 18 : 1. All quantified data represent an average of at least three independent experiments. Illustration and statistical significance are as described for Figure 2.
