Fig. 4
Heterochromatin organization protects hUC-MSCs from Dox- or H2O2-induced DNA damage and cellular senescence. a Representative photos and quantification of immunofluorescence staining of H3K9me3 and HP1γ in Dox-induced hUC-MSCs at different time points (scale bar = 10 μm). 1 × 104 hUC-MSCs (p5-p7) were seeded on coverslip and treated with Dox. The cells were washed with PBS and incubated in the fresh media for 24 h. Quantification is shown below, mean ± SEM of values from three independent experiments with triplicate wells analyzed on 6–8 cells/field from five different fields. *p < 0.05; **p < 0.01;***p < 0.001 by Student’s t test. b β-gal staining indicates Chaetocin aggravates Dox-induced cellular senescence. 2 × 105 hUC-MSCs (p5-p7) were seeded in 6-well plates and treated with Dox with or without Chaetocin. The cells were collected 2 days afterward. Data are presented as the mean ± SEM. *p < 0.05;**p < 0.01 by one-way ANOVA with Tukey’s post hoc test. c Representative images and quantification of immunofluorescence staining of H3K9me2/3 and γ-H2AX in control or Chaetocin-treated hUC-MSCs in response to Dox (scale bar = 10 μm). 1 × 104 hUC-MSCs (p5-p7) were seeded on coverslip and treated with Dox with or without Chaetocin. The cells were collected 24 h afterward. Quantification is shown below, mean ± SEM of values from three independent experiments with triplicate wells analyzed on 6–8 cells/field from five different fields. **p < 0.01;***p < 0.001 by one-way ANOVA with Tukey’s post hoc test. d Representative Western blot image of H3K9me3 and γ-H2AX in Dox-induced hUC-MSCs senescence with or without Chaetocin. 2 × 105 hUC-MSCs (p5-p7) were seeded in 6-well plates and treated with Dox with or without Chaetocin. The cells were collected at different time points. Quantification data is shown below. Data are achieved from three independent experiments. *p < 0.05; **p < 0.01;***p < 0.001 by two-way ANOVA with Bonferroni post hoc test first, followed by paired Student t test