γ-氨基丁酸信号对小鼠胎盘发育的调控及分子机理研究

Mammalian placentation is critical for successful pregnancy and depend on the precise trophoblast differentiation and invasion into maternal decidua, otherwise pregnant-related disorders such as early pregnancy loss, fetal growth restriction, hydatidiform mole will take place. γ-aminobutyric acid(GABA) is one type of classical neurotransmitters. Interestingly, GABA signal recently was found to participate in the maintenance of pregnancy in rats and to mediate decidualization of uterine stromal cells in human. Our previous study showed that GABA and its receptors were expressed dynamicly in developing placenta, and exogenetic GABA cause dysplasia of spongiotrophoblast,labyrinth, maternal vascular reconstruction and fetal angiogenesis in mice, suggesting that GABA signal is of great significance to the development of placenta. In this study, we are going to examine the expression patterns of GABA signal both in mice and trophoblast stem cell by real time PCR, in situ hybridization, western blotting and immunohistochemistry. Secondly, to investigate the function of GABA signal, specific chemical agonist or antagonist will be applied to activate or block its receptors. Alternatively, lentivirus-mediated placenta-specific treatment will be applied to increase or decrease expressions of the receptors. Finally, we will further investigate how GABA signal affects placentation and vascular reconstruction in vivo by phenotyoe analysis, and how GABA signal mediates the biological behavior of trophoblast cells in vitro by MTS, stem cell differentiation models, matrigel invasion and transwell migration assay. Hopefully, this study is anticipated to elucidate the role and molecular mechanism of GABA signal in mouse placentation.

哺乳动物胎盘发生是成功妊娠的关键环节，胎盘滋养层细胞分化和侵润母体蜕膜异常将导致流产、胎儿生长受限或葡萄胎等疾病。γ-氨基丁酸（GABA）是一种经典的神经递质。在生殖领域，已证实GABA与大鼠妊娠的维持和人类子宫内膜的蜕膜化有关。课题组前期发现，GABA及其受体动态表达于发育的小鼠胎盘，且外源性GABA导致胎盘海绵滋养层和迷路层的结构改变，母体血管的重建和胎儿血管的发生异常，提示GABA信号对胎盘发育具有重要意义。本研究以小鼠和滋养层干细胞系为模型，首先通过定量PCR、蛋白印迹和IHC等检测GABA信号的表达，然后采用化学药物或慢病毒介导的胎盘受体特异性敲低手段，在体条件下，通过表型分析研究GABA信号对胎盘发育和血管重建的影响，离体条件下，利用MTS、干细胞分化模型和细胞侵袭模型等，研究GABA信号对滋养层细胞生物学行为的影响，以期阐明GABA信号在小鼠胎盘发育中的作用及分子机理。

γ-氨基丁酸（γ- aminobutyric acid，GABA）是中枢神经系统重要的抑制性神经递质，通过与其相应受体特异性结合发挥生理功能，如降血压、抗焦虑、改善睡眠和提高记忆力等。此外，在外周组织，如肝脏、胰腺、子宫和卵巢等也有GABA及其受体的存在，参与细胞间的信号传递及内分泌调节等。在生殖系统，已证实GABA与大鼠妊娠的维持和人类子宫内膜的蜕膜化有关。本项目以小鼠为模型，首先明确了GABA信号在妊娠早期子宫和发育胎盘的时空表达模式；随后通过人工诱导蜕膜化模型、延迟着床模型和基质细胞体外蜕膜化模型以及药物在体干预等手段，明确了GABAB1与胚胎的植入和子宫内膜的蜕膜化密切相关，且GABA通过其B型受体，参与小鼠胎盘发育过程滋养层细胞的增殖和分化、母体血管的改建和胎儿血管的发生；最后基于GABA信号参与妊娠早期事件，结合GABA作为一种新资源食品被年轻白领广泛使用的现状，通过体内外实验，探讨妊娠早期GABA摄入对胚胎植入的影响及其机制。研究发现，植入前各个发育阶段的胚胎都有GABA及其GABAB1的表达，且GABA能通过GABAB1受体调节早期胚胎的发育。妊娠早期12.5mg/g/天的GABA摄入，能抑制早期胚胎的发育、削弱子宫内膜的容受性，从而影响胚胎的植入。以上结果提示：GABA信号可能参与了小鼠胚胎的发育、植入和胎盘的发育过程。项目的完成，为胚胎植入和小鼠胎盘发育的分子机理提供重要的实验证据。同时，也为GABA在食品和保健品中的安全使用提供有价值的参考。