O-GlcNAc糖基化修饰通过代谢重编程抑制ART小鼠胎盘血管生成的机制研究

Assisted reproductive technology (ART) results in abnormal placental angiogenesis in humans and many animals, but its mechanism is unclear. We previously found that the level of angiogenesis in placental labyrinth layer was significantly decreased, and the levels of O-GlcNAc transferase (OGT) and HIF-1α protein were also significantly decreased by ART in mouse placenta. Considering that the OGT could regulate the glycometabolism by modifying the pyruvate kinase M2 (PKM2) with O-GlcNAc which affects HIF-1α stability, we proposed the hypothesis that down-regulation of ART placental OGT expression could cause the decrease of O-GlcNAc modification level of PKM2, which increased the enzyme activity and the level of Krebs cycle, and finally promoted HIF-1α degradation and inhibited placental angiogenesis. On the basis of the previous work, firstly ART mouse model and mouse cell line will be used to reveal the mechanism of inhibiting placental angiogenesis by down-regulation of OGT that induced by ART. Secondly, the molecular mechanism of the down regulation of OGT expression in ART placenta will be elucidated by ChIP technique. Finally, the intervention strategy of preventing and treating placental angiogenesis abnormality of ART will be explored by using small molecule Thiamet G. The completion of the project will reveal the new mechanism of abnormal placental angiogenesis induced by ART and provide scientific basis and experimental support for the abatement of adverse pregnancy outcomes originating from ART.

ART致人类及多种动物胎盘血管生成异常，但其发生机制不明。我们前期发现，ART致小鼠胎盘迷路层血管生成水平显著下降，且O-GlcNAc糖基转移酶（OGT）与HIF-1α蛋白水平显著下调。鉴于OGT可通过O-GlcNAc修饰丙酮酸激酶PKM2调控糖代谢影响HIF-1α稳定性，我们提出ART胎盘OGT表达下调，致PKM2的O-GlcNAc修饰水平降低、酶活性升高，三羧酸循环代谢增强，最终促使HIF-1α降解，抑制胎盘血管生成的假说。本课题拟在前期工作的基础上，首先，利用ART小鼠模型和细胞系，揭示ART致OGT下调，抑制胎盘血管生成的发生机制；其次，通过ChIP技术，阐明ART致胎盘OGT表达下调的分子机制；最后，利用小分子Thiamet G，探索防治ART胎盘血管生成异常的干预策略。本项目的完成，将揭示ART致胎盘血管生成异常的新机制，为消减ART源不良妊娠结局提供理论和实验支持。