Hippo信号通路在调控哺乳动物原始卵泡启动中的作用及机制研究

Clarifying the molecular mechanisms by which the initiation of primordial follicles is regulated is crucial for the prevention and treatment of female infertility and premature ovarian failure. Recent reports have shown that changes of ovarian cortical density could trigger the onset of the primordial follicle. On the other hand, Hippo signaling pathway which consists of several oncogenes（Mst/Lats/Yap）could sense the changes of cell density in Drosophila ovary. Our prelimilary data in mice showed that Hippo component Yap had dramatic expression changes after initiation of primordial follicles. Thus, we hypothesize that Hippo signaling pathway may trigger the initiation of primordial follicles in mammals. In this project, utilizing mouse and human ovary samples, we will analyze the correlation between the expression levels of key molecules in the Hippo signaling pathway and the changes of the primordial follicle pools. At the same time, through genetically manipulating the Hippo pathway, the effects and related mechanisms of Hippo pathway regulation on the initiation of primordial follicle will be explored. Furthermore, the development potentiality and fertility of primordial follicles activated by Hippo pathways modulation will be investigated. The applicant has extended research experience in the field of primordial follicles development and maturation（Reprod Biol Endocrinol，2010；DNA and Cell Biology, 2012）, hoping the success of this project will provide valuable scientific basis for the diagosis and treatment of the related female reproductive disorders...

阐明原始卵泡启动的分子机制对于防治女性不孕症和卵巢早衰具有重要意义。最近研究表明，卵巢皮层密度变化能触发原始卵泡的启动，而在果蝇中的研究显示由多个癌基因（Mst/Lats/Yap）参与的Hippo信号通路可感知卵巢细胞密度的变化。我们前期实验发现Yap在小鼠原始卵泡启动前后有显著性差异，故我们假设Hippo信号通路可能是哺乳动物原始卵泡启动的触发机制。本课题拟以小鼠和人卵巢组织为实验对象，分析Hippo通路相关信号分子的表达与原始卵泡池大小变化的时序相关性；通过基因工程手段调控Hippo通路，研究其对原始卵泡启动的影响及相关机制；进一步观察调控下的原始卵泡后期发育及受精潜能。申请人有良好的卵泡发育调控研究基础（Reprod Biol Endocrinol，2010；DNA and Cell Biol, 2012），相信本课题将为诊疗女性相关生育疾病提供有价值的理论依据。

阐明原始卵泡启动的分子机制对于防治女性不孕症和卵巢早衰具有重要意义。Hippo信号通路是通过感知细胞密度变化从而调控细胞再生、增殖及凋亡的关键通路。近年有研究表明，卵巢皮层密度变化可触发原始卵泡的启动，但具体作用及机制未见报道。本课题以小鼠和人卵巢组织为实验对象，主要包含以下研究内容：① 分析Hippo通路相关信号分子的表达变化与原始卵泡池大小变化的时序相关性；② 利用基因转染和条件性消减观察调控Hippo信号通路对原始卵泡启动的影响；③ 观察Hippo信号通路在重要信号分子AKT调控原始卵泡启动中所扮演的角色与作用； ④ 利用基因工程调控Hippo通路后观察对病理性卵泡耗竭卵巢发育情况及受精能力等后续发育潜能的变化。研究结果发现：① Hippo通路主要组分MST1、LATS2、YAP1在小鼠、人卵巢内均有表达，且随着原始卵泡池变小，Hippo通路活性发生变化。② 原始卵泡启动与Hippo通路活性衰减密切相关，Hippo通路主要效应分子YAP1活性变化可显著影响原始卵泡启动过程。③ Hippo通路介导AKT调控原始卵泡启动，YAP1上调可部分反转因AKT下调所致的对原始卵泡启动的抑制作用。④ 化疗性卵巢功能损伤与Hippo通路受抑密切相关，利用YAP1过表达载体可显著改善其卵巢功能。以上结果提示，Hippo通路是调控原始卵泡静息/启动的重要信号通路，其可作为卵巢功能异常治疗的重要靶标。