Fig. 1

Telomere shortening enhances classical markers of cellular senescence in brain cells. a qPCR analysis of telomere length in cortical DNA samples from WT and successive generations (G1-G4) of Terc^−/− mice. Average telomere length was calculated as the ratio (T/S) of the telomere repeat copy number (T) to a single copy gene copy number (S = 36B4). *P < 0.05, ***P < 0.001 (One-way ANOVA with Tukey’s post-hoc analysis, n = 2–5 mice/group). b mRNA levels of the SASP factors Il1b, Il6, Cxcl1, and the cyclin-dependent kinase inhibitors p16^Ink4a (p16), p19^Arf (p19) and p21^waf1/cip1 (p21), were measured by RT-qPCR in cortical extracts from 5-month-old WT and G3Terc^−/− mice. *P < 0.05 (two-tailed Student’s t-test, n = 4–8). c qPCR analysis of telomere length (T/S ratio) in primary neurons derived from WT and G3Terc^−/− mice. **P < 0.01 (two-tailed Student’s t-test, n = 3 cultures/group). d mRNA levels of Il1b, Il6, Cxcl1, p16^Ink4a (p16), p19^Arf (p19) and p21^waf1/cip1 (p21), were measured by RT-qPCR in WT and G3Terc^−/− primary neurons. *P < 0.05 (two-tailed Student’s t-test, n = 3–4 cultures/group). e Primary neurons obtained from WT and G3Terc^−/− mice were stained for SA-β-gal, followed by immunostaining using the selective neuronal marker MAP2 (red), and the percentage of SA-β-gal-positive neurons was calculated. *P < 0.05 (two-tailed Student’s t-test, n = 3 cultures/group). Scale bar: 100 μm. All data are presented as the mean ± SEM