MRS2179 augments structural synaptic integrity. (A and B) The density of hippocampal CA1 synaptic puncta, quantified as colocalization of synaptophysin and Homer1 immunoreactivity, was reduced in vehicle-treated APPPS1 mice (Veh) compared with WT littermates, but similar to WT in MRS2719-treated APPPS1 mice (APPPS1 + MRS2719, n = 5 mice; APPPS1 + vehicle, n = 5 mice; WT, n = 4 mice; age of all groups, 11 mo; *, P < 0.05, Kruskal–Wallis test followed by Dunn’s multiple comparisons test; mean ± SEM). Bar, 20 µm. (C and D) The periplaque area covered by dystrophic neurites, measured by LAMP1 immunoreactivity, was reduced in MRS2179-treated compared with vehicle-treated APPPS1 mice (APPPS1 + MRS2719, n = 5 mice; APPPS1 + vehicle, n = 4 mice; age of both groups, 11 mo; *, P < 0.05, Mann–Whitney test; mean ± SEM). Bar, 300 µm.