Fig. 4

APOE4-associated alterations in microglia behaviors are worsened with aging. A Quantification of microglia density in EC and CA1 of 12- and 21-month-old mice. Bars represent the mean ± SEM cell density in analyzed fields, symbols (circles, male; triangle females) represent data points for each animal. 2–3 brain slices per animal, 3–4 animals per genotype per sex per age. Two-way ANOVA with Tukey’s multiple comparison post-hoc analyses, *p = 0.014. B-C Quantification of microglial endpoint/cell (B) and branch length/cell (C) in the EC and CA1 of 12- and 21-month-old mice. Bars represent the mean ± SEM microglial endpoint/cell and branch length/cell in analyzed fields, and symbols (circles, male; triangle, females) represent data points for each animal. 2–3 brain slices per animal, 3–4 animals per genotype per sex per age. D Bars represent the average motility index of all analyzed microglia ± SEM, and points represent data from each microglia 3–4 animals per genotype per sex per age. Two-way ANOVA with Tukey’s multiple comparison post-hoc analyses *p = 0.022. E 12- and 21- months old APOE3 (E3) and APOE4 (E4) microglia responding to patch pipette containing ATP (shown as dashed triangle) in the CA1 and EC. Scale bar 20 µm. F Processes velocity in the CA1 (C) and EC (D) in response to 1 mM ATP. Bar graphs represent the mean velocity ± SEM. Individual points represent the average process velocity (3 processes per cell) of each microglia (3–5 cells per animal), 3–4 animals per genotype per sex (6 months old). Two-way ANOVA with Tukey’s multiple comparison post-hoc analyses *p < 0.05, **p = 0.006. G Comparison of velocity of microglial processes in response to 1 mM ATP in 6-month (shown in Fig. 3), 12-, and 21-month-old mice. Two-way ANOVA with Tukey’s multiple comparison post-hoc analyses; data are compared to 6-month-old mice for either EC or CA1. ****p = 0.0001