Fig. 5: Enlarged endo-lysosomes and increased vulnerability phenotypes in the neurons treated with γ-secretase inhibitor.

A Neurons were treated with 1 μM DAPT or vehicle control for 16 h. The accumulation of APP-C-terminal fragments (APP-CTFs) is indicative of γ-secretase inhibition. B The size of endo-lysosomes in the neurons treated with 1 μM DAPT or vehicle control was assessed by LysoPrime Green. Scale bar 20 μm. N = 93–97 neurons. Mann–Whitney U test, ****<0.0001 (C) Neurons expressing the YC 3.6. sensor were treated with 1 μM DAPT or vehicle control for 16 h, and baseline Ca²⁺ levels were compared. N = 59–80 neurons. n.s.: not significant (D) Post 5 min recording baseline Ca²⁺ levels, the neurons pre-incubated with DAPT or vehicle were treated with 100 μM Glu, and the changes in Ca²⁺ levels were recorded overtime for 15 min. N = 61–81 neurons. Repeated ANOVA, ****<0.0001. E The neurons expressing the C99 Y-T biosensor were pre-incubated with 1 μM DAPT or vehicle control for 16 h, followed by 100 μM Glu, (F) or 100 μM DTDP for 30 min. Relative numbers of PI (+) neurons over those expressing the C99 Y-T biosensor were measured from 11–13 independent experiments (Veh-veh set as 1). One-way ANOVA, *<0.05, **<0.01, ***<0.001.