叶酸代谢障碍引起的胚胎发育异常中H19/IGF2印记基因的表观遗传调控机制

Folate dysmetabolism caused by folate deficiency is closely related to neural tube closure in embryonic development, but the causal metabolic pathway and the underlying mechanism remains obscure. Our team preliminary study has demonstrated that the abnormal imprinting establishment may be involved in NTDs. In the study, we intend to establish a NTDs mice and primary cultured neural stem cells induced by disturbing the methylated metabolites. Based on these experiment, we try to study that the interactions in miR483, H3K27 histone modifications and H19/IGF2. Folate dysmetabolism disturbs the signal network regulation which affecting cell proliferation, apoptosis, differentiation, migration induced the the occurrence of NTDs. The epigenetic in F1 and F2 is intended to study whether changes of miR483, H3K27 histone and H19/IGF2 modifications caused neural tube closure. The study will explain the mechanism of NTDs in the signal network regulation of imprinting establishment. Further display the clinical and experimental evidence to improve the nutrition during pre-pregnant and pregnant to decrease the incidence of abnormal embryo development.

叶酸缺乏引起的代谢障碍影响胚胎发育早期神经管的闭合，但是如何引起NTDs的机制尚未阐明。本课题组前期研究发现，叶酸代谢障碍中的NTDs病例中印记建立异常可能是引起NTDs的机制之一。本研究通过阻断DNMT酶来模拟叶酸代谢障碍通路中甲基化异常代谢途径，诱导构建NTDs小鼠模型和取材NTDs畸形表型的胎鼠胎脑做原代神经干细胞培养，初步探讨叶酸代谢障碍对H19/IGF2的印记修饰，miR483与H3K27甲基化修饰之间的表观信号网络的调控，进而影响了神经管闭合发育过程中的细胞增殖，凋亡，分化，迁移等行为，最终导致了NTDs的发生；还通过干预F0代小鼠印记的建立观察F1代小鼠印记情况，再观察F2代孕鼠中印记的模式及对神经管闭合的影响，为进一步阐明NTDs的发病机制提供实验依据，为临床改善孕前和孕早期营养预防胚胎发育异常提供可靠的实验证据。

叶酸缺乏引起的代谢障碍影响胚胎发育早期神经管的闭合，但是如何引起NTDs的机制尚未阐明。SAM与神经管畸形发生密切相关，甲基供体缺乏引起印记基因表观修饰调控网络异常是导致发育障碍的机制之一。本项目利用不同药物阻碍甲基供体在体内的代谢成功诱导出了NTDs小鼠模型，取材NTDs畸形表型的脑组织做原代神经干细胞培养，发现H19/IGF2的印记修饰，miR483与H3K27甲基化修饰之间的表观信号网络的调控异常，影响了神经管闭合过程中细胞增殖，凋亡，分化，迁移等行为。在细胞模型中发现随着药物剂量的增加，miR483的甲基化水平和mRNA水平是负相关；同时影响了H19/IGF2的印记修饰的紊乱，在胎鼠脑组织中也验证了H3K27甲基化修饰是异常的。在分子水平上，增殖相关基因表达降低，凋亡相关基因表达上调。干预F0代小鼠印记的建立影响了后代小鼠脑组织中H19/IGF2的印记修饰。本项目采用不同甲基供体代谢阻断药物构建神经管畸形模型，从动物模型和细胞模型两个层面对表观遗传网络相关的基因进行检测和分析，并且探究甲基供体缺乏对神经发育表观遗传学机制，为进一步阐明NTDs的发病机制提供实验依据，为临床改善孕前和孕早期营养预防胚胎发育异常提供可靠的实验证据。