LncRNA-PVT1基因异常甲基化的调节机制及其在子痫前期发生中的作用研究

Pre-eclampsia (PE) have gained much attention by clinical and basic researchers worldwide. Numerous studies demonstrated that abnormal placentation was the key element in the pathogenesis of PE, however, the specific molecular mechanisms involved remain to be established. Our recent studies have discovered that the lncRNA-PVT1, related to organ injury and abnormalities, was hypomethylated in the placentas of PE. Besides, the expression level of PVT1 lncRNA induced by aberrant DNA methylation was down-regulated in the placentas of PE. Previous studies have indicated that the up-regulation of PVT1 lncRNA was related to the occurrence of metastatic tumors. In the present project, we will explore the molecular mechanism of the hypomethylation of lncRNA-PVT1 and its role in the pathogenesis of PE at three levels including the clinical samples, cell lines, and animal model. We will analyze the methylation level of genomic region neighboring the targeted CpG site in the placentas of PE; reveal the role of folic acid and DNA methylation related enzymes in regulating aberrant lncRNA-PVT1 methylation; detect the influence of aberrant PVT1 lncRNA expression on trophoblast cell growth and function; investigate the important role of PVT1-MYC and other interacting proteins in the pathogenesis of PE. The results may add new molecular mechanisms involved in the pathogenesis of PE. Furthermore, our findings may also provide theory basis for clinical controlling of PE, and provide therapeutic targets for PE.

子痫前期（PE）是全世界备受重视的研究领域。大量研究显示，胎盘发育和功能受损是PE发生的关键因素，但其分子机制仍有待研究。本实验室前期发现与器官损伤和异常相关的lncRNA-PVT1基因在PE胎盘中呈显著低甲基化，且引起PVT1 lncRNA表达下调。已知PVT1与细胞增殖、迁移等功能密切相关。本项目将在临床样本、细胞系和动物模型三个层面对PE胎盘组织lncRNA-PVT1异常甲基化的调控机制及其在PE发生中的作用进行研究。检测PE胎盘lncRNA-PVT1的甲基化状态，探讨叶酸水平、甲基化相关作用酶在lncRNA-PVT1异常甲基化中的调控作用；检测PVT1 lncRNA异常表达对滋养层细胞生长和功能的影响；探讨PVT1-MYC及其他互作蛋白在PE发生中的作用机制。研究结果将为PE发生机制增加新的分子理论基础，为临床实践中降低PE的发生风险提供理论依据，为PE的临床治疗提供潜在药物靶点。

子痫前期作为一种产科常见并发症，是备受重视的研究领域。胎盘异常的表观遗传修饰已得到证实，而表观遗传因素也可能是妊娠异常的表征之一。项目实施过程中，我们运用最新标准流程重新分析DNA甲基化谱数据，开展了PE胎盘中PVT1基因异常甲基化的调节机制研究，在细胞层面探讨异常PVT1表达在子痫前期发生中的机制；整合了重新分析的DNA甲基化芯片结果及从GEO（Gene Expression Omnibus）网络数据库上获取的其它5项子痫前期胎盘相关独立研究的芯片数据作为材料进行荟萃分析，通过对大量PE相关胎盘DNA甲基化关联研究数据的分析和挖掘，证明EOPE胎盘中广泛分布的，较温和的低DNA甲基化DMPs特征，并与临床症状的严重程度相关。我们检测胎盘中DNA甲基化代谢过程中关键酶的表达水平，发现EOPE胎盘中从头DNA甲基转移酶DNMT3A和DNMT3B的表达下调，上述结果提示EOPE胎盘发育过程中合体滋养细胞的DNA甲基化修饰未能正常建立。DNA甲基化可能通过调控受累基因的表达，参与PE的发病过程，更重要的是，DNA甲基化作为最稳定的表观遗传修饰可维持细胞的亚稳态表型，对于疾病的维持和发展起到重要作用。研究结果将为PE发生机制增加新的分子理论基础，为临床实践中降低PE的发生风险提供理论依据，为PE的临床治疗提供潜在药物靶点。