Fig. 5: Psen1^KI/KI microglia accumulate more PSD-95 in an Alzheimer’s disease mouse model.

a Accumulation of PSD-95 within microglia from mice hippocampus. Microglial volumes were generated based on IBA1 immunoreactivity (green). Scale bar: 5 µm. b Volumetric quantification of the PSD-95 inside microglia in wild-type, Psen1^KI/KI, 5xFAD and 5xFAD*Psen1^KI/KI mice. c Representative z projection micrographs of the presynaptic marker synaptophysin (green) and the post-synaptic marker PSD95 (red) in the hippocampal hilus and molecular layer e. The micrographs correspond to the maximum intensity projection of 150 z-stacks across a 6 µm z-depth (see supplemental video 4 for 3D representation). Left to right: Wild-type (WT), Psen1^KI/KI (KI), 5xFAD (AD), and 5xFAD * Psen1^KI/KI (AD*KI) mice. A 4× higher magnification image in WT (blue box, 5 µm × 5 µm) was used to reveal the synaptophysin and PSD-95 spot pairs, as indicated within the white circle. Quantification of synapses in the hippocampal hilus (d) and molecular layer (f) as compared to their WT littermate controls. The 3D localization of presynaptic synaptophysin and postsynaptic PSD-95 puncta are identified using the “create spots” algorithm in Imaris (for details see Methods). Mice were 3 months old. Data are represented as mean ± SEM. N = 8–12 microglia per group, 3 mice per group. *p < 0.05, **p < 0.01, ***p < 0.001 using one-way ANOVA followed by Duncan’s Method.