Fig. 7
Aggravated synaptic dysfunction, neuronal loss and cognitive decline in the absence of Cx3cr1. (A) Representative western blots to assess the levels of pre-synaptic proteins—Synaptic Vesicle Protein-2 (SV2a), Synaptophysin and Homer, and post-synaptic proteins—Post-Synaptic Density-19 (PSD19) and NMDA Receptor subunit 1 (NR1) in cortical lysates of 6 month-old 5xFAD;Cx3cr1+/+ and 5xFAD;Cx3cr1−/− mice and their genotype matched controls. Blots representative of n = 6 (3 females, 3 males) per genotype. (B) Visualization and quantitation of NeuN+ neuronal abundance in the subiculum of 4- and 6 month-old 5xFAD;Cx3cr1+/+ (black bars) and 5xFAD;Cx3cr1−/− mice (grey bars). Images representative of NeuN+ neurons in subiculum of 6 month-old cohorts. Scale bars = 100 µm. Histological analyses and related quantification performed using multiple, serial sections from n = 6 mice (3 females, 3 males), of each genotype and at each time-point. Error bars represent SEM. Statistical analysis done using Two-way ANOVA (pint = ns) followed by Tukey’s post-hoc tests. ***p = 0.0002, **p < 0.005. Densitometric analysis to quantify fold changes in (C) pre-synaptic proteins and (D) post-synaptic markers in cortical lysates of B6;Cx3cr1+/+ (white bars), B6;Cx3cr1−/− (light grey bars), 5xFAD;Cx3cr1+/+ (black bars) and 5xFAD;Cx3cr1−/− (dark grey bars) mice 5xFAD;Cx3cr1−/− (dark grey bars). Fold changes were calculated using blots from n = 6 animals (3 females, 3 males) of each genotype run on the same gel to enable comparisons. Statistical analyses done using One-way ANOVA followed by Brown-Forsythe and Welch’s post-hoc tests. *padj < 0.05, **padj < 0.001, ***padj < 0.0001, ****padj < 0.00001. (E) Y-maze based evaluation of working memory in 6 month-old B6;Cx3cr1+/+ mice (white bars), B6;Cx3cr1−/− (light grey bars), 5xFAD;Cx3cr1+/+ (black bars) and 5xFAD; Cx3cr1−/− (dark grey bars). Behavioral testing done using ~ n = 10 animals (5 females, 5 males) per genotype. Statistical analysis done using One-way ANOVA followed by Brown-Forsythe and Welch’s post-hoc tests. *padj = 0.02, ***p.adj < 0.0001, ns = not significant