国内外资料报道和本课题组前期研究表明：间充干细胞（MSCs）可诱导分化为心肌样细胞，组蛋白乙酰化修饰扮演着重要角色, 但低分化问题限制了其临床应用，关键是分化机制尚未完全明了，故探明MSCs特化心肌细胞的调控网络至关重要。由此，在课题组研究和相关理论基础上，我们提出假设：DNA甲基化与组蛋白乙酰化交互作用开启或沉默特异基因表达，促MSCs向心肌细胞特化。本课题拟采用高表达Islet-1慢病毒载体转染、去甲基化诱导剂与去乙酰化酶抑制剂处理MSCs，分别检测不同时间点Islet-1、心肌早期发育基因Nkx2-5、Gata4和Mef2c表达及其启动子区域甲基化、组蛋白乙酰化水平变化，阐明MSCs向心肌样细胞分化过程中特异基因的DNA甲基化和组蛋白乙酰化时序变化、交互调控及其机制。该研究将进一步明确MSCs分化表观调控网络，为MSCs应用于临床替代病变心肌组织、促进心脏功能恢复奠定坚实的实验基础。

Recent studies have confirmed that mesenchymal stem cells (MSCs) can be induced to differentiate into cardiomyocyte-like cells.The data reported in the literature and from our group have shown that histone acetylation modification plays an important role in the process of specific differentiation of MSCs into cardiomyocyte-like cells. However,the MSC differentiated level is low, which limits its clinical applications.The key problem is that the mechanisms underlying the induced differentiation are not yet fully understood.It is critical to understand the regulatory network in the differentiation process from MSCs to cardiomyocyte-like cells in a three-dimensional space. Based on our previous experimental data and other reported theories, we hypothesize that: mechanism for the timely modification of cardiac specific gene in regulating MSC differention to cardiomyocytes is associated with DNA methylation and its interaction with histone acetylation.The following specific aims have been developed to address our hypothesis.We will use Islet-1 gene that can cause MSC differentiation as an example and overexpress it in mouse embryonic MSCs. The methylation level in cardiac specific gene promoter regions will be measured with MSP and the methylation sites are detected by methylation microarray and bioinformatics analyses. Meanwhile,the state of histone acetylation on these genes will be monitored as well. In consistent with our preliminary data, we predict that the proposed study will figure out the interacting regulatory network between DNA methylation and histone acetylation during the process of MSC differentiation into cardiomyocyte-like cells.The results obtained will help us to understand better the regulatory network of epigenetics and be useful for the clinical application of stem cells for replacing injured myocardial cells and restoring damaged cardiac function.