Cardiovascular Genetics Center, Biomedical Research Institute of Girona, 17190 Salt, Spain.
Department of Medical Sciences, Universitat de Girona, 17003 Girona, Spain.
Int J Mol Sci. 2021 Mar 9;22(5):2755. doi: 10.3390/ijms22052755.
The gene encodes the α-subunit of the voltage-gated cardiac sodium channel (Na1.5), a key player in cardiac action potential depolarization. Genetic variants in protein-coding regions of the human have been largely associated with inherited cardiac arrhythmias. Increasing evidence also suggests that aberrant expression of the gene could increase susceptibility to arrhythmogenic diseases, but the mechanisms governing expression are not yet well understood. To gain insights into the molecular basis of gene regulation, we used rat gastrocnemius muscle four days following denervation, a process well known to stimulate expression. Our results show that denervation of rat skeletal muscle induces the expression of the adult cardiac isoform. RNA-seq experiments reveal that denervation leads to significant changes in the transcriptome, with amongst the fifty top upregulated genes. Consistent with this increase in expression, ChIP-qPCR assays show enrichment of H3K27ac and H3K4me3 and binding of the transcription factor Gata4 near the promoter region. Also, Gata4 mRNA levels are significantly induced upon denervation. Genome-wide analysis of H3K27ac by ChIP-seq suggest that a super enhancer recently described to regulate in cardiac tissue is activated in response to denervation. Altogether, our experiments reveal that similar mechanisms regulate the expression of in denervated muscle and cardiac tissue, suggesting a conserved pathway for expression among striated muscles.
该基因编码电压门控心肌钠通道（Na1.5）的α亚基，是心肌动作电位去极化的关键因子。人类蛋白编码区域的基因变异与遗传性心律失常有很大关联。越来越多的证据表明，基因的异常表达可能会增加心律失常疾病的易感性，但调控基因表达的机制尚不清楚。为了深入了解基因调控的分子基础，我们使用大鼠腓肠肌在去神经四天后进行研究，该过程众所周知会刺激基因表达。我们的结果表明，大鼠骨骼肌的去神经会诱导成人型心脏基因的表达。RNA-seq 实验表明，去神经导致转录组发生显著变化，其中基因在五十个上调基因中排名靠前。与这种表达增加一致，ChIP-qPCR 检测显示 H3K27ac 和 H3K4me3 的富集以及转录因子 Gata4 在基因启动子区域附近的结合。此外，去神经后 Gata4 mRNA 水平显著诱导。ChIP-seq 对 H3K27ac 的全基因组分析表明，最近在心脏组织中描述的一个超级增强子在去神经后被激活，以调节基因的表达。总的来说，我们的实验表明，类似的机制调控了去神经肌肉和心肌组织中基因的表达，这表明在横纹肌中存在一个保守的基因表达途径。
