Fig. 2From: Rejuvenating aged microglia by p16ink4a-siRNA-loaded nanoparticles increases amyloid-β clearance in animal models of Alzheimer’s diseaseCdkn2a and its coding protein p16ink4a are increased in senescent microglia, but not astrocytes or neurons, in postmortem brains of patients with Alzheimer’s disease and 8-month-old 5XFAD mice. A Top 5 gene ontology biological process pathways involved in Aβ42-positive microglia from old mice compared with young mice. The upper panel (red) and lower panel (blue) show the pathways enriched by increased and decreased gene expression, respectively. FDR: false discovery rate. B Heat map representing gene expression relating to replicative senescence (GO0090399) in Aβ42-positive microglia (MG) from young and old mice (n = 4 for each group). The scale represents the Z-score from 2.3 (highest expression) to − 2.3 (lowest expression). The bar graph reveals the ratio of the gene expression levels in Aβ42-positive microglia between young and old mice. C Western blot of the protein levels of p16ink4a in brain tissue from WT and 5XFAD mice. ACTB: β-actin. D Immunohistochemistry of p16ink4a and DAPI staining in brain tissue from WT and 5XFAD mice. Scale bar: 100 µm. E Quantification of the protein levels in (D). ***p < 0.005, 5XFAD versus WT; unpaired Student’s t test. F Z-stack confocal images of p16ink4a (red) with Aβ plaque (green). Scale bar: 20 µm. G Representative images show p16ink4a expression (purple) with Iba1 or GFAP immunostaining. Representative images were constructed using Imaris software. Scale bar: 20 µm. H The percentage of p16ink4a expression per cell volume. ***p < 0.005, Iba1 versus GFAP; unpaired Student’s t testBack to article page