Fig 2: GDF11 activated telomerase and inhibited telomere shortening in NRCMs under AR.A Representative photographs of telomeres measured by Q-FISH in NRCMs. B Quantitative analysis of the TL of TEL-CY3-positive cells. C TL measured by real-time PCR. D The activity of telomerase. E Representative western blot images and semiquantitative analysis of TERT. F mRNA expression of TERT, TERF2, POT1, TPP1, TERF1, and RAP1. &p < 0.05 vs. the NC group; *p < 0.05 vs. the AR group; #p < 0.05 vs. the oe-GDF + AR group; n = 6 in each group in panel (B) and n = 5 per group in panels (C–G); one-way ANOVA followed by Bonferroni’s correction for post hoc multiple comparisons in panel (B–D, F, G). (B) The telomerase inhibitor BIBR1532; GDF11 growth differentiation factor 11, oe-GDF11 GDF11 overexpression, TL telomere length.

Fig 3: An illustration of the influences of GDF11 on IR/AR injury and the underlying mechanisms.Patients with CAD, especially ACS, and rodent cardiomyocytes subjected to IR or AR insult, exhibit lower circulatory or myocardial GDF11 levels, leading to lower activity of telomerase and shorter TL in the nucleus due to downregulation of TERT, inhibiting mitochondrial energy dynamics and the antiapoptotic PI3K/Akt/FoxO3a pathway and activating the proapoptotic p53/Bax pathway. These changes collectively increase cardiomyocyte apoptosis, enlarge the myocardial infarct size and eventually promote cardiac remodeling. The changes can be antagonized and enhanced by overexpression and silencing of GDF11, respectively, and the beneficial effects of GDF11 can be attenuated by the telomerase inhibitor BIBR1532. ?: activation, ?: inhibition.?: from other reference.¦: experimentally proven.

Fig 4: Effects of GDF11 on the myocardial IS, survival and cardiac remodeling in mice subjected to IR.Adenovirus carrying GDF11 (oe-GDF11) or adenovirus carrying sh-GDF11 were injected into the myocardium. A Representative pictures of Evans blue and triphenyl tetrazolium chloride (TTC) double-stained myocardial sections from mice subjected to 45 min of ischemia/24 h of reperfusion. Scale bar = 2 mm. B AAR in the four groups at 24 h after surgery; n = 5, one-way ANOVA. C Myocardial IS in the four groups at 24 h after surgery; n = 5, one-way ANOVA followed by Bonferroni’s correction for post hoc multiple comparisons. D Four-week survival curves of the six groups. &p < 0.05 vs. the sham group; #p < 0.05 vs. the oe-GDF11 + IR group, Kaplan–Meier survival analysis. E Myocardial scar size at 4 weeks after surgery; n = 10, one-way ANOVA followed by Bonferroni’s correction for post hoc multiple comparisons. F The heart weight (HW)/body weight (BW) ratio at 4 weeks after surgery; n = 10–15, one-way ANOVA followed by Bonferroni’s correction for post-hoc multiple comparisons. G The HW/TiL ratio at 4 weeks after surgery; n = 10–15, one-way ANOVA followed by Bonferroni’s correction for post hoc multiple comparisons. H The lung weight (LW)/BW ratio at 4 weeks after surgery; n = 10–15, one-way ANOVA followed by Bonferroni’s correction for post-hoc multiple comparisons. I The LW/TiL ratio at 4 weeks after surgery; n = 10–15, one-way ANOVA followed by Bonferroni’s correction for post-hoc multiple comparisons. &p < 0.05 vs. the sham group; *p < 0.05 vs. the IR group; #p < 0.05 vs. the oe-GDF11 + IR group. GDF11, growth differentiation factor 11; IR ischemia/reperfusion, TiL tibia length, AAR area at risk, IS infarct size.

Fig 5: Effects of overexpressing or silencing GDF11 on IR-induced myocyte apoptosis in mice.A Representative photographs of TUNEL-stained cells. B Quantitative analysis of TUNEL-positive cells. C Representative images and semiquantitative analysis of western blots for Bax, P53, p-P53, C-caspase3, Caspase3, and Bcl2. D Representative images and semiquantitative analysis of western blots for PI3K, Akt, FoxO3a, and p-Akt. &p < 0.05 vs. the sham group; *p < 0.05 vs. the IR group; #p < 0.05 vs. the oe-GDF11 + IR group; n = 5, one-way ANOVA followed by Bonferroni’s correction for post-hoc multiple comparisons in panel (B, D, F). GDF11 growth differentiation factor 11, IR ischemia/reperfusion, oe-GDF11 GDF11 overexpression, sh-GDF11 short hairpin of GDF11.