Fig. 2.
Spermidine altered AD-associated microglia and their capacity to degrade Aβ. a Cluster abundance in snRNA-seq of male spermidine-treated APPPS1 and H2O APPPS1 mice with p values from mixed-effects binomial model. b Volcano plot of genes differentially expressed in microglia cluster 2 vs. 1. The top 5 up- and down-regulated genes are indicated as well as previously published markers for homeostatic (yellow) and disease-associated (blue) microglia [1]. Significance threshold of adj. p value < 0.01 was used. Axl as a gene of interest is highlighted in red. c Tissue sections of male 180-day-old mice were stained for the microglia cluster 2 marker AXL (red) and IBA1 (green). The AXL intensity normalized to the IBA1 area was determined by ImageJ analysis; n = 6–10, two‐tailed t‐test. d Neonatal microglia were pre-treated for 18 h with 10 µM spermidine and fluorescently labelled oligomeric (Aβo) Aβ (magenta) was added for further 24 h. Microglia cells were stained for IBA1 (green). The percentage of phagocytic cells and the Aβ mean intensity density per phagocytic cell was assessed by confocal microscopy. Representative images are shown; n = 7, two‐tailed t‐test. *p < 0.05, **p < 0.01, ***p < 0.001