TBX5 and myocardial infarction: Moreover, intramyocardial injections of GATA4, MEF2C and TBX5 (GMT)-encoding retrovirus and 2 weeks i.p. injections of SB431542 (transforming growth factor-β inhibitor) and XAV939 (glycogen synthase kinase 3β inhibitor) after MI induced improvement of ejection fraction and reduced the scar size by remuscularisation41.