Fig. 1: Plaque-associated microglia include PU.1low subpopulation.
From: Lymphoid gene expression supports neuroprotective microglia function
a, Uniform manifold approximation and projections (UMAPs) of ex vivo isolated forebrain microglia from 8-month-old wild-type and 5xFAD mice (two males per group) show distinct PU.1 expression states (PU.1low, PU.1med and PU.1high) among DAM12 (red). b,c, PU.1 protein is reduced in a subset of plaque-associated microglia in the cortex of 6-month-old 5xFAD mice (n = 5; one female and four males) (b) and in the frontal cortex of individuals with AD (79–91 years; n = 3; one female and two males) (c). Bar graphs show the proportion of PU.1low cells in plaque-associated microglia versus distal microglia, analysed using a paired two-tailed t-test. d,e, Plaque-associated PU.1low microglia are resistant to CSF1R inhibition (CSF1Ri). d, UMAP visualizations of lineage-traced cortical microglia (TRAP28) from 6-month-old control (one female) or CSF1Ri-fed 5xFAD mice (two males), analysed using single-nucleus sequencing (DAM outlined with dotted line). The pie chart shows PU.1low fraction within DAM. e, Reduced PU.1 protein expression in CSF1Ri-resistant cortical microglia in the cortices of 6-month-old CSF1Ri (n = 4; one female and three males) versus control diet-fed (n = 8 mice; six females and two males) 5xFAD mice. Bar graph shows the proportion of PU.1low microglia, analysed using an unpaired two-tailed t-test. f, Microglial SYK/PLCγ2 signalling promotes the plaque-associated PU.1low state. Representative images and quantification of PU.1 expression in cortical microglia from 6-month-old 5xFAD;Cx3cr1CreErt2/+ (n = 5; three females and two males), 5xFAD–SYK-KO (5xFAD;Cx3cr1CreErt2/+;Sykfl/fl; n = 3; one female and two males) and 5xFAD–PLCγ2-KO mice (5xFAD;Cx3cr1CreErt2/+;Plcg2fl/fl; n = 3; two females and one male). Bar graphs show plaque-normalized microglial numbers and PU.1low microglia fractions, as determined by ordinary one-way ANOVA with multiple comparisons. Microglial nuclei identified using Imaris (b,f) and CellProfiler (e) in dotted circles. Bar graphs show the mean ± s.e.m. with individual points. Scale bars, 20 μm (b,c,f), 40 μm (d), 10 μm (e). Illustrations in a, d and f were created using BioRender (https://biorender.com).
