输卵管CDC42信号调控胚胎转运的功能和分子机制研究

Ectopic pregnancy is a major reproductive health problem in early pregnancy. Impaired tubal transport function results in embryos retention in the fallopian tube, which is the main reason of ectopic pregnancy, but the underlying mechanism needs to be uncovered. Based on previous and our preliminary studies, we speculated that CDC42 of oviductal epithelial cells regulates the function of epithelial cells and smooth muscle cells, and abnormal CDC42 signaling pathway is a new mechanism for embryo transport retention and ectopic pregnancy. We proposed a key scientific issue - "Molecular mechanism of CDC42 signal regulating embryonic transport in the fallopian tube?", and will employ the mouse model of Cdc42 conditional knockout, in vitro model of embryo transport in oviduct, human oviductal epithelial cell line, human oviduct samples, to investigate :1) Physiological and pathological role of CDC42 signaling pathway in the process of embryo transport; 2) Molecular mechanism of CDC42 mediated cell polarity regulating oviductal epithelial cells and cilia; 3) New molecular mechanism of oviductal epithelial CDC42 signaling regulating smooth muscle cell function. It is hoped that a better understanding of the molecular regulatory network in the process of embryo transport in oviduct will provide a theoretical basis of the pathogenesis of ectopic pregnancy.

异位妊娠是早期妊娠阶段主要的生殖健康问题，输卵管转运功能受损导致胚胎阻滞在输卵管中是异位妊娠发生的关键原因，但其分子调控机制远未阐明。依据现有文献和前期工作，我们推测：输卵管上皮细胞CDC42信号调控上皮细胞纤毛摆动和平滑肌细胞伸缩功能，CDC42信号通路异常是输卵管转运胚胎阻滞和异位妊娠发生的一种新机制。基于此，我们提出关键科学问题—“输卵管CDC42信号调控胚胎转运的分子机制？”，拟利用Cdc42条件性敲除小鼠模型、输卵管转运胚胎体外模型、人输卵管上皮细胞系、临床输卵管样本系统研究：1）CDC42信号通路在输卵管转运胚胎过程中的生理病理作用；2）CDC42介导上皮细胞极性调控输卵管上皮细胞和纤毛功能的分子机制；3）输卵管上皮细胞CDC42信号调控平滑肌细胞功能的新分子机制。希望通过上述研究进一步揭示输卵管转运胚胎过程中的分子调控网络，为阐明异位妊娠的发病机制提供理论基础。

异位妊娠是一种早期妊娠阶段极大危害生殖健康的问题。输卵管上皮纤毛细胞在卵子、精子和胚胎的转运过程中均起到重要作用，输卵管上皮细胞功能受损导致胚胎阻滞在输卵管中是异位妊娠发生的关键原因，但其分子调控机制远未阐明。我们的研究利用Cdc42条件性敲除小鼠模型、输卵管上皮细胞类器官模型、临床输卵管样本系统研究CDC42对输卵管转运胚胎的作用和调控纤毛上皮细胞分化的分子机制。我们发现：1．输卵管峡部特异性敲除Cdc42导致胚胎在输卵管峡部转运受阻、早期妊娠失败；2．缺失Cdc42导致输卵管上皮细胞间的连接和完整性受损；3．输卵管上皮缺失Cdc42导致纤毛细胞减少、调控纤毛细胞分化的关键转录因子下调；4．CDC42调控输卵管上皮分泌细胞向多纤毛细胞分化，但不依赖CDC42酶活性和Notch信号通路；5．CDC42通过与PI3K的p110β亚基互作调控AKT信号活性，抑制PI3K-AKT信号导致分泌细胞向纤毛细胞分化失败，激活AKT信号可以部分挽救Cdc42缺失导致的纤毛细胞分化障碍；6．异位妊娠患者的输卵管上皮细胞中CDC42、pAKT表达降低，纤毛细胞比例减少，下调人输卵管上皮细胞PI3K-AKT通路抑制纤毛细胞分化。总之，我们新发现 CDC42-PI3K-AKT 信号是小鼠输卵管和人输卵管中多纤毛细胞分化的调控信号轴，为理解女性异位妊娠提供新的思路。