Department of Cardiology, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, Jiangsu, The People's Republic of China.
Department of Haematology, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, Jiangsu, The People's Republic of China.
PLoS One. 2023 Aug 29;18(8):e0289510. doi: 10.1371/journal.pone.0289510. eCollection 2023.
Sick sinus syndrome (SSS) is a a life-threatening disease, and biological pacemakers derived from bone marrow mesenchymal stem cells (BMSCs) have practical clinical applications. Previous studies demonstrated that epigenetics plays an important role in the differentiation of BMSCs into pacemaker-like cells. However, the underlying mechanisms remain unclear. In the present study, we investigated the role of DNA methylation and histone methylation in pacemaker cells formation and found that changes in DNA and H3K9 methylation occur in the promoter region of the pacemaker cell-specific gene HCN4. In addition, the combined addition of methylation inhibitors was able to improve the efficiency of transduction of Tbx18 in inducing the differentiation of BMSCs into pacemaker-like cells. In vitro experiments have shown that inhibition of DNA methylation and H3K9 methylation can enhance the activity of the HCN4 promoter activity, and both can affect the binding of the transcription factor NKx2.5to the HCN4 promoter region. Further research on the interaction mechanism between DNA methylation and H3K9me2 in the HCN4 promoter region revealed that the two may be coupled, and that the methylesterase G9a and DNMT1 may directly interact to bind as a complex that affects DNA methylation and H3K9me2 regulation of HCN4 transcription. In conclusion, our studies suggest that the mutual coupling of DNA and H3K9 methylation plays a critical role in regulating the differentiation of BMSCs into pacemaker-like cells from the perspective of interactions between epigenetic modifications, and combined methylation is a promising strategy to optimise pacemaker-like cells for in vitro applications.
病态窦房结综合征（SSS）是一种危及生命的疾病，来源于骨髓间充质干细胞（BMSCs）的生物起搏器具有实际的临床应用。先前的研究表明，表观遗传学在 BMSCs 分化为起搏样细胞中起着重要作用。然而，其潜在的机制尚不清楚。在本研究中，我们研究了 DNA 甲基化和组蛋白甲基化在起搏细胞形成中的作用，发现起搏细胞特异性基因 HCN4 的启动子区域中发生了 DNA 和 H3K9 甲基化的变化。此外，联合添加甲基化抑制剂能够提高 Tbx18 转导诱导 BMSCs 分化为起搏样细胞的效率。体外实验表明，抑制 DNA 甲基化和 H3K9 甲基化可以增强 HCN4 启动子活性，并且两者都可以影响转录因子 NKx2.5 与 HCN4 启动子区域的结合。进一步研究 HCN4 启动子区域中 DNA 甲基化和 H3K9me2 之间的相互作用机制表明，两者可能是偶联的，并且甲基转移酶 G9a 和 DNMT1 可能直接相互作用形成复合物，从而影响 HCN4 转录的 DNA 甲基化和 H3K9me2 调控。总之，我们的研究表明，从表观遗传修饰相互作用的角度来看，DNA 和 H3K9 甲基化的相互偶联在调节 BMSCs 分化为起搏样细胞中起着关键作用，联合甲基化是优化体外应用起搏样细胞的一种有前途的策略。
