Fetal and adult human heart RNA promotes myofibrillogenesis and stimulates a heart beat in cardiac non-function mutant Mexican axolotl hearts in organ culture

The Mexican axolotl (Ambystoma mexicanum) carries a cardiac lethal mutation resulting in mutant embryos with no heartbeat. This homozygous recessive gene results in tropomyosin deficiency and absence of organized myofibrils. Co-culturing mutant hearts with bioactive RNA, termed myofibril-inducing RNA (MIR), from normal axolotl embryonic anterior endoderm causes the mutant hearts to beat. It is hypothesized that the secondary structure of the MIR binds a specific protein(s) and this is required to synthesize tropomyosin and form organized myofibrils. In this study mutant hearts are co-cultured with human fetal and adult heart total RNA to assess rescue of the mutant hearts. Results show that both human fetal and adult heart total RNA rescue the mutant condition in a manner similar to the MIR. Thus, the MIR human functional homologs induce events leading to normal heart differentiation and function. This finding may help people with heart muscle damage regain normal heart function again.