Fig 2: Aß-induced gene expression of senescence in human microglial cells. (a–h) Human microglial cells were treated with 10 µM Aß for different times. (a–d) Relative genes expression levels of PAI-1, p21, CCND1, and CCNA1 were measured by qPCR. (e) Protein levels of p53, PAI-1, and p21 were detected by western blotting. (f–h) The quantification of relative protein levels in (e). (i–n) Human microglial cells were stimulated with Aß (1-10 µM) for 72 h. (i) Western blotting was used to investigate protein levels of p53, PAI-1, and p21. (j–l) The quantification of relative protein levels in (i). (m) The representative SA-ß-gal staining images. (n) Quantification of the percentage of SA-ß-gal cells. Scar bar, 100 µm. (o–q) Senescence-associated proinflammatory cytokines such as TNF-a, IL-1ß, and IL-6 were detected by qPCR. The data are presented as mean ± SEM, n = 3 independent experiments; *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001, analyzed by one-way ANOVA followed by Bonferroni's test.

Fig 3: Overexpression of SIRT1 rescues Aß-induced senescence and mitochondrial dysfunctions. (a–i) Human microglia cells HMC3 were transfected with SIRT1 plasmid (150 ng) or FUGW (150 ng) followed by Aß treatment for 72 h. (a) Protein levels of SIRT1, PAI-1, and p21 were investigated by western blotting. (b) The quantification of relative protein levels in (a). (c) The representative SA-ß-gal staining pictures. (d) Quantification of the percentage of SA-ß-gal cells. Scar bar, 50 µm. (e) Nuclear Nrf2 and Cyto Nrf2 were detected after SIRT1 overexpression. (f) The quantification of relative protein levels in (e). (g) The cells were incubated with JC-1 dye and the fluorescence intensity was quantified using BioTek reader. (h) HMC3 cells were stained with DCFH-DA and Hoechst; then, the fluorescence intensity was detected by BioTek reader. (i) The fluorescent latex beads were added to the medium and incubated at 37°C for 3 h. The fluorescence intensity was quantified using BioTek reader. The data are presented as mean ± SEM, n = 3 independent experiments; *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001, analyzed by one-way ANOVA followed by Bonferroni's test.