miR-134在三氯生暴露致早期胚胎发育障碍中的作用与机制研究

miR-134, a kind of miRNA which is screened from miRNA array, is significantly increased in mouse embryonic stem cell exposed to TCS and is highly conserved between human and mouse. It is still lack of clear functional coverage in early embryonic development; bioinformatics analysis and experiment show that Nanog is a candidate target of miR-134. Our previous study showed that TCS exposure could increase the expression level of miR-134 and decrease Nanog level; miR-134 overexpression could block early embryonic development and increase fetal loss rate, consistent with that TCS exposure increased fetal loss rate in pregnancy mice. According to these results, we propose that TCS may block early embryonic development and increase fetal loss rate by increasing the expression level of miR-134 and decreasing the level of Nanog. To demonstrate this hypothesis, our study apply overexpression, silent strategy and save test to verify that the function of miR-134 in TCS’s effects on early embryonic development. The research has a source of innovative, and will help to clarify the mechanism of TCS exposure on early embryonic development. This provides scientific basis for reducing the potential risk of TCS on reproduction and development.

miR-134 是我们通过miRNA 芯片获得的、人鼠高度同源的、差异高表达于TCS暴露的小鼠胚胎干细胞，在早期胚胎发育中功能未知的一个miRNA。生物信息学分析及实验证实Nanog为其靶基因；TCS暴露可上调小鼠胚胎干细胞中miR-134表达，下调Nanog表达水平；早期实验证实miR-134过表达可以引起早期胚胎发育阻滞和胚胎丢失率增加，与TCS暴露引起妊娠小鼠胚胎丢失的结果一致。提示TCS暴露可能通过引起miR-134表达升高，导致下游Nanog的表达水平降低，进而引起早期胚胎发育阻滞和胚胎丢失。本研究拟采用过表达、沉默策略及挽救实验策略，从正反两面论证miR-134在TCS暴露影响早期胚胎发育中的作用。研究将有助于阐明TCS暴露影响早期胚胎发育的相关机制，为有效减少TCS的潜在生殖发育毒性作用提供一定的理论基础和科学依据。

抗菌剂三氯生（TCS）被广泛用于个人护理和消毒产品中。它对生殖和发育健康都存在潜在的危害。但不幸的是，其产生危害的潜在机制仍不清楚。在本研究中，我们通过使用RNA干扰技术，免疫荧光染色方法，以及拯救实验来探讨TCS对小鼠植入前胚胎发育的毒性作用及可能的机制。我们的研究结果表明：小鼠受精卵暴露于2-200μMTCS染毒液，可致囊胚形成率显著下降，胚胎发育主要阻滞于桑葚胚阶段；且miR-134在桑葚胚中的表达量随着TCS浓度上升而不断上升，而其下游调节基因Nanog在桑葚胚中的表达量随着TCS浓度上升而不断下降；miR-134在小鼠受精卵中过表达可致小鼠囊胚形成率下降，且胚胎发育同样阻滞于桑葚胚时期，与暴露于TCS后表型一致；Nanog表达量在miR-134过表达的桑椹胚中显著下降，在TCS染毒后的桑椹胚中也显著下降；注射miR-134 inhibitor 及 Nanog mRNA片段可使TCS暴露后的胚胎囊胚形成率有所恢复。总之，我们的研究显示TCS可能通过上调miR-134和下调Nanog的表达水平（miR-134 / Nanog信号轴）来影响植入前胚胎发育的进程。