Extended Data Figure 8: Effects of anti-miR-25 on cardiac function of WT and Serca2a-null hearts.

a–e, Anti-miR-25 or control (scrambled sequence) anti-miRNA was administered intravenously to sham-operated wild-type mice (Sham) or to unoperated Serca2a-cardiomyocyte null (S2a KO) mice³⁸, as for the experiments in Fig. 4 (see Methods). Sham-operated animals were injected with anti-miRNAs 1 week after surgery and followed by echocardiography. S2a KO animals were generated by injection with 4-OH tamoxifen intraperitoneally for 4 days (see Methods) to delete Serca2a, then injected with anti-miRNAs 1 week later and followed by echocardiography. a, Representative two-dimensional guided M-mode images of the LVs from wild-type and S2a KO mice. b, c, Echocardiographic indices of left ventricular inner dimension during diastole, LVIDd (b), and systole, LVIDs (c) (n = 3 (sham plus control); 8, (sham plus anti-miR-25); 7 (S2a KO plus control); 11 (S2a-KO plus anti-miR-25) 4 weeks after control or anti-miRNA injection. d, Echocardiographic measurement of fractional shortening (FS) expressed as a percentage at time points after control or anti-miRNA injection (n = 4 (sham plus control); 3 (sham plus anti-miR-25); 3 (S2a KO plus control); 3 (S2a KO plus anti-miR-25)). S2a KO mice show characteristic dilation and decline in cardiac function after 4-OH tamoxifen-induced excision of Serca2a³⁹. ***P < 0.001 (Student’s t-test for difference between S2a KO and sham-operated control anti-miRNA groups at week 4 after injection). e, Haemodynamic effect of anti-miR-25 and control anti-miRNA injection is represented by pressure–volume plots of treatment cohorts as indicated 4 weeks after injection of control or anti-miRNA. Note that specific anti-miR-25 and control anti-miRNA acted similarly in sham-operated wild-type animals (n = 3 (sham plus control); 3, (sham plus anti-miR-25); 2 (S2a KO plus control); 3 (S2a-KO plus anti-miR-25). Moreover, anti-miR-25 did not increase cardiac function of S2a KO mice, unlike TAC-operated wild-type mice (Fig. 4), suggesting that the beneficial effect on cardiac function depends on SERCA2a. Data are represented as mean ± s.e.m. n = number of biological replicates (all included). NS, not significant.