Figure 1. The lysosomal modulator PADK selectively enhances cathepsin B levels in APP_SwInd mice.

The 10–11-month transgenic mice (tg) were injected i.p. daily with either PADK (20 mg/kg; n = 13) or vehicle (veh; n = 10) for 9 days. Brain homogenates from the transgenic mice and from vehicle-treated wildtypes (wt; n = 13) were analyzed by immunoblot for the active form of cathepsin B (CB), neprilysin (nep), insulin-degrading enzyme (IDE), α-secretase (α-sec), and actin (A). Mean immunoreactivities±SEM were determined by image analysis and plotted. Hippocampal photomicrographs from vehicle- (B) and PADK-treated mice (C) show cathepsin B immunostaining (green) in pyramidal neurons counterstained with anti-NeuN (red); view-field width is 75 µm. The CA1 zone was assessed for cathepsin B immunoreactivity (mean intensity±SEM) in the pyramidal layer (D) and for the number of cathepsin B-positive puncta per neuron (E). Tukey post hoc test: **P<0.001; unpaired t-test: ***P<0.0001.