Effects of hyperacetylation of H3K9ac mediated by histone acetylases on the overexpression of MEF2C induced by alcohol in the hearts of fetal mice during pregnancy

Abstract

Objective To investigate the effects of H3K9ac hyperacetylation mediated by histone acetylases on the overexpression of MEF2C in the hearts of fetal mice exposed to alcohol during pregnancy, and provide new intervention targets for prevention and treatment of cardiac dysplasia caused by alcohol exposure. Methods C57BL/6 mice were divided into 5 groups randomly, blank control group, dimethylsulfoxide (DMSO) group, alcohol group, alcohol+ anacardic acid group and anacardic acid group, and then the hearts of fetal mice were collected to be analyzed.Chromatin immunoprecipitation and Western blot were used in assaying the binding of histone acetylases and the level of H3K9ac to the promoter of MEF2C in the hearts of fetal mice.The mRNA expression of MEF2C was tested by adopting real-time PCR. Results The level of H3K9ac in the promoter of MEF2C in the hearts of fetal mice exposed to alcohol was higher than that in the hearts of fetal mice exposed to saline (1.30±0.19 vs 0.45±0.01), there was statistically significant difference (P<0.05), while the binding of E1A-binding protein (p300), p300/cyclic adenosine monophosphate response element binding protein-associated factor (PCAF) and steroid receptor coactivator-1 (SRC1) to the promoter of MEF2C were abnormally elevated in the hearts of fetal mice treated by alcohol (1.68±0.08 vs 0.82±0.08, 1.08±0.05 vs 0.42±0.02, 1.18±0.05 vs 0.39±0.08), and there were statistically significant differences (all P<0.05). The expression of MEF2C mRNA in alcohol group was higher than that in blank control group (1.36±0.12 vs 0.29±0.03), there was statistically significant difference(P<0.05). However, a pan-acetylases inhibitor, anacardic acid, could decrease significantly the binding of p300 and PCAF to the promoter of MEF2C (1.52±0.05 vs 0.63±0.09, 1.13±0.04 vs 0.45±0.04), and correct abnormal hyperacetylation of H3K9ac induced by alcohol (1.58±0.08 vs 0.67±0.05), and down-regulate the over-expression of MEF2C in the hearts of fetal mice exposed to alcohol (1.36±0.12 vs 0.41±0.05), and there were statistically significant differences (all P<0.05). Conclusions Hyperacetylation of H3K9ac mediated by p300 and PCAF may be a key regulatory factor in the over-expression of cardiac nuclear transcription factor MEF2C in the hearts of fetal mice exposed to alcohol during pregnancy.Anacardic acid can significantly attenuate the level of H3K9ac through inhibiting the binding of p300 and PCAF to the promoter of MEF2C, and down-regulate the over-expression of cardiac nuclear transcription factor MEF2C in the hearts of fetal mice. Key words: Histone acetylases; Transcription factor; Alcohol; Acetylation; Overexpression