GATA4在冠状动脉平滑肌表型转化过程中的作用机制

The phenotypic modulation of coronary artery vascular smooth muscle cell (VSMC) is highly associated with the occurrence and development of coronary artery disease (CAD). Our previous study found that, mutations of GATA4, the member of GATA zinc finger transcription factor family, exist in patients with ventricular septal defect. Among them, the de novo mutation p.S335X could result in deletion of C terminus of GATA4 and thus lead to apoptosis of cardiac cells. Mitogen-activated protein kinase (MAPK) plays important part in the phenotypic modulation of VSMC, and GATA4 is a key downstream pathway of ERK1/2 and p38, the members of MAPK family. However, the role of GATA4 in the phenotypic modulation of coronary artery VSMC has not been well investigated yet. The present project will study the followings by using in vitro cell culture model and in vivo animal model: 1) the effects of GATA4 on the expression of phenotypic modulation-related genes in coronary artery VSMC, so as to identify the phenotypic modulation-related genes regulated by GATA4; 2) the mechanisms of GATA4 on regulating the genes mentioned above, involving the roles of activation of ERK1/2 and p38 signaling pathways. To clarify the molecular biological mechanisms by which GATA4 affects the phenotypic modulation process of VSMC and accounts for the mobidity of CAD, could deepen our understanding about the pathogenesis of CAD, and could provide new idea and scientific basis for prevention and treatment of CAD.

冠状动脉血管平滑肌细胞（VSMC）表型转化与冠状动脉疾病（CAD）发生发展密切相关。我们前期发现GATA4在先天性室间隔缺损患者中的新突变p.S335X导致GATA4C端缺失，促进心肌细胞凋亡。丝裂原活化蛋白激酶（MAPK）在VSMC表型转化过程中具关键作用，GATA4是ERK1/2和p38的重要下游途径。我们预实验显示阻断内皮素（ET）系统可有效抑制表型转化相关基因表达的改变，涉及MAPK家族信号转导途径的激活，与GATA4功能有密切联系。但GATA4对冠状动脉VSMC表型转化的作用机制未明。本项目拟以离体细胞和在体动物模型研究：GATA4对冠状动脉VSMC表型转化相关基因表达的影响，确定GATA4所调控的具体表型转化相关基因；GATA4调控上述基因的分子生物学机制，ERK1/2和p38信号转导途径激活在其中的作用。明确GATA4影响VSMC表型转化过程、参与CAD发病的分子生物学机制。

GATA4 p.S335X突变可致GATA4 C端缺失，促进心肌细胞凋亡，但其在冠状动脉平滑肌细胞（CASMC）中的作用尚不明确。本研究中，我们构建了GATA4野生型（WT）和p.S335X突变型（MU）过表达载体，建立大鼠CASMC细胞培养模型，结合细胞生物学、分子生物学、生物信息学手段，研究细胞的表型转化情况及相关基因的表达谱改变，筛选关键的受调控基因，为进一步的机制研究提供理论依据。研究结果表明：正常状态下和炎症状态下，GATA4 MU主要通过改变CASMC的增殖能力而非迁移能力，导致细胞表型转化；表型转化相关基因表达谱改变；确认了下述关键基因的表达受调控：Fas、Hbegf、Itga5、Aimp1、Cxcl1、Il15、Il2rg、Il7、Tnfsf10、Il1r1、Irak1、Tlr3。本项目结果有助于理解GATA4及其突变体对CASMC表型转化的作用和参与冠状动脉疾病的机制。