Figure 4

Expression of TREM2, an Aβ42 receptor, is decreased in aging microglia. (a) Heatmap representation of phagocytic receptor gene expression levels for Young Aβ42⁺, Young Aβ42⁻, Old Aβ42⁺, and Old Aβ42⁻. The scale represents the row Z-score from 2 (highest expression) to − 2 (lowest expression). Young (2 months) and aged (21 months) microglia were incubated with 0.5 μM Aβ42 for 1 h and stained for microglial markers and TREM2 (n = 3/group; replicated 4 times with both male and female mice) (b) Representative flow plots (n = 3/group) of young and aged microglia TREM2 expression and graph of % of young and old microglia that are TREM2⁺. (c) Representative flow plots of young and aged microglia TREM2 expression and Aβ42 uptake. (d) Graphs showing the average percentage of TREM2 expression in young (black) and old (red) Aβ42⁺ microglia and (e) Average percentage of Aβ fluorescence in young (black) and old (red) TREM2⁺ microglia. (f) Geometric mean fluorescence of Aβ42 in TREM2⁺ and TREM2⁻ Aβ42⁺ microglia. *p ≤ 0.05, **p ≤ 0.01, mean ± s.e.m, Student’s t Test.