Fig. 1
From: Trem2 Y38C mutation and loss of Trem2 impairs neuronal synapses in adult mice
Trem2 Y38C variant and Trem2 deficient mice affects microglial morphology. a CRISPR/Cas9 strategy to generate the tyrosine to cystine point mutation (red) in exon 2 of murine Trem2 to create the Trem2Y38C/Y38C mouse model. The sequences for the reference genome, guide RNA, and homology directed repair (HDR), which indicates the Y38C variant (red) and a silent mutation (blue) to ablate the protospacer adjacent motif (PAM), are shown. b Quantification of Trem2 mRNA levels in cortical lysates showed similar Trem2 expression in WT (black) and Trem2Y38C/Y38C (green) mice and no expression in Trem2−/− (red) mice. Data are presented as mean ± SEM fold change normalized gene expression relative to WT. N = 8 (4 males and 4 females for each group) c Immunohistochemistry for TREM2 (green) and Iba-1 (red) is shown in cortices of 6 month WT, Trem2Y38C/Y38C, and Trem2−/− mice. Merged imaged indicates colocalization of TREM2 staining with Iba-1+ (red) cell bodies in WT and Trem2Y38C/Y38C mice. No TREM2 staining was observed in Trem2−/− mice. (representative images from females). d Quantification of total TREM2 in WT, Trem2Y38C/Y38C, and Trem2−/− cortical lysates by ELISA indicates slightly higher levels of TREM2 in Trem2Y38C/Y38C as compared to the WT mice. e sTREM2 levels, quantified in TBS soluble cortical extracts, were similar in both Trem2Y38C/Y38C and WT. f Quantification of the number of Iba-1 positive cells showed similar counts in cortices of 6 months old WT, Trem2Y38C/Y38C and Trem2−/− mice. g Quantification of Iba-1 immunoreactive area showed increased staining in Trem2Y38C/Y38C and Trem2−/− mice. f-g Data represented as mean ± SEM, N = 6 (3 males and 3 females for each group; n = 56 fields for WT, n = 89 fields for Trem2Y38C/Y38C, and n = 112 fields for Trem2−/−). h Skeletonized reconstructions (representative reconstructions from females), i quantification of number of branches and j number of junctions in microglia from the cortices of 6 months old WT, Trem2Y38C/Y38C and Trem2−/− mice. h-j Data represented as mean ± SEM, N = 6 (3 males and 3 females for each group, each data point represents microglia analyzed). b,d-i One-way ANOVA with Tukey’s post hoc test. * P < 0.05, ***P < 0.001, ****P < 0.0001