Abstract
Molecular switches of myosin isoforms are known to occur in various conditions. Here, we demonstrated the result from fetal heart failure and its potential mechanisms. Fetal and adult heart failure rat models were induced by injections of isoproterenol as previously described, and Go6976 was given to heart failing fetuses. Real-time PCR and Western blot were adopted to measure the expressions of α-MHC, β-MHC and YY-1. Co-immunoprecipitation was performed to analysis whether YY-1 interacts with HDAC5. Besides, histological immunofluorescence assessment was carried out to identify the location of HDAC5. α-MHC was recorded elevated in fetal heart failure which was decreased in adult heart failure. Besides, YY-1 was observed elevated both in fetal and adult failing hearts, but YY-1 could co-immunoprecipitation with HDAC5 only in adult hearts. Nuclear localization of HDAC5 was identified in adult cardiomyocytes, while cytoplasmic localization was identified in fetuses. After Go6976 supplied, HDAC5 shuttled into nucleuses interacted with YY-1. The myosin molecular switches were reversed with worsening cardiac functions and higher mortalities. Regulation of MHC in fetal heart failure was different from adult which provided a better compensation with increased α-MHC. This kind of transition was involved with shuttling of HDAC5 regulating YY-1 function.