Down-regulation of EBAF in the heart with ventricular septal defects and its regulation by histone acetyltransferase p300 and transcription factors smad2 and cited2.

ABSTRACT

As a NODAL pathway inhibitor, EBAF plays a critical role during mammalian cardiac development. As recent tests that have been conducted on gene-targeted mice indicate, its expression is frequently altered where cardiac defects are present. We aimed to explore the EBAF expression pattern and molecular mechanism of EBAF gene for VSD genesis. In this report, we show that the average expression of EBAF in the disease tissues of VSD patients was lower than the expression in normal fetuses without VSD. Further study showed that the expression pattern of EBAF was potentially involved in cardiomyocyte apoptosis by Annexin-V and RT-PCR assays. We also found that abnormal activation of NODAL-PITX2C pathway was associated with down-regulation of EBAF. By luciferase reporter assays, we find that EBAF expression is mediated by transcriptional factors smad2 and cited2. In addition, ChIP assays showed that histone acetyltransferase p300 is involved in the activation of EBAF through inducing hyperacetylation of histone H4 at the EBAF promoter. Co-immunoprecipitation also indicates that the expression of EBAF is regulated by a transcriptional complex including p300, smad2, and cited2. This study revealed a novel regulator mechanism of EBAF, which may be a potential molecular target for halting the onset of VSDs. They also indicate that smad2, cited2, and p300 may play important roles in modulating the confirmation of ventricular septal defects.