Figure 7: E2F1 promotes mitochondrial fragmentation and apoptosis.

(a) Cardiomyocytes were exposed to H₂O₂. Cells were harvested at the indicated time for the analysis of E2F1 levels by immunoblot. Data are shown as mean±s.e.m. of three independent experiments. *P<0.05 versus untreated group in Student’s t-test. (b,c) Enforced expression of E2F1 induces mitochondrial fragmentation and apoptosis. Cardiomyocytes were infected with adenoviral E2F1 or β-gal. Forty-eight hours after infection mitochondrial fragmentation (b) and apoptosis (c) were analysed. Data are shown as mean±s.e.m. of three independent experiments. Analysis was performed with one-way analysis of variance (ANOVA) followed by Tukey–Kramer post hoc analysis. *P<0.05 versus untreated group. (d) Cardiomyocytes were infected with adenoviral E2F1-siRNA or E2F1-sc, and then exposed to H₂O₂. E2F1 levels were detected by immunoblot. Data are shown as mean±s.e.m. of three independent experiments. Analysis was performed with one-way ANOVA followed by Tukey–Kramer post hoc analysis. *P<0.05. (e) Knockdown of E2F1 reduces mitochondrial fragmentation and apoptosis. Cardiomyocytes were treated as described in d, mitochondrial fragmentation (upper panel) and apoptosis (lower panel) were analysed. Data are shown as mean±s.e.m. of three independent experiments. Analysis was performed with one-way ANOVA followed by Tukey–Kramer post hoc analysis. *P<0.05. (f,g) E2F1-knockout mice attenuates mitochondrial fragmentation and apoptosis on I/R. WT and E2F1-knockout mice were subjected to I/R as described in Methods. Mitochondrial fragmentation (f) and apoptosis (g) were analysed. Data are shown as mean±s.e.m. of six independent experiments. Analysis was performed with one-way ANOVA followed by Tukey–Kramer post hoc analysis. *P<0.05 versus WT+I/R. (h) E2F1-knockout mice attenuates myocardial infarction sizes on I/R. WT and E2F1-knockout mice were subjected to I/R as described in f. The upper panels are representative photos of midventricular myocardial slices. The lower panel shows infarct sizes. Data are shown as mean±s.e.m. of six independent experiments. Analysis was performed with one-way ANOVA followed by Tukey–Kramer post hoc analysis. *P<0.05 versus WT+I/R. Bar=2 mm.