Homozygous or compound heterozygous frameshift mutations in MYBPC3 encoding cardiac myosin-binding protein C (cMyBP-C) cause neonatal hypertrophic cardiomyopathy (HCM), which rapidly evolves into systolic heart failure and death within the first year of life. Here we show successful long-term Mybpc3 gene therapy in homozygous Mybpc3-targeted knock-in (KI) mice, which genetically mimic these human neonatal cardiomyopathies. A single systemic administration of adeno-associated virus (AAV9)-Mybpc3 in 1-day-old KI mice prevents the development of cardiac hypertrophy and dysfunction for the observation period of 34 weeks and increases Mybpc3 messenger RNA (mRNA) and cMyBP-C protein levels in a dose-dependent manner. Importantly, Mybpc3 gene therapy unexpectedly also suppresses accumulation of mutant mRNAs. This study reports the first successful long-term gene therapy of HCM with correction of both haploinsufficiency and production of poison peptides. In the absence of alternative treatment options except heart transplantation, gene therapy could become a realistic treatment option for severe neonatal HCM.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.