背景:已知KITL-KIT相互作用是通过PI3K-AKT-FOXO3信号传导的下游途径激活卵母细胞的重要引发剂。先前的研究利用生殖细胞特异性Kit突变体敲入和激酶结构域敲除模型与Vasa-Cre表明KIT在原始卵泡期卵母细胞激活中的关键作用。
方法:我们通过Gdf9-iCre利用卵母细胞出生后KIT表达完全缺失的小鼠,并对卵巢卵泡发育进行了分析,特定标记,激素检测,和生育结果。
结果:我们的发现揭示了与以前的产前Kit缺失的小鼠模型相比的对比表型。具体来说,出生后Kit的缺失在生殖细胞巢破裂中没有缺陷,卵泡激活,和发育过程中的卵泡生成。值得注意的是,在达到完全成熟时,出生后缺失Kit的小鼠经历卵巢储备的完全丧失,正在生长的卵泡,和卵巢功能。此外,小鼠表现出更小的卵巢大小和重量,卵泡发育延迟,和指示原发性卵巢功能不全(POI)的表型,包括血清FSH水平升高,降低AMH,没有卵泡,最终导致不孕。此外,卵巢表现出随机分布的颗粒细胞和卵泡膜细胞标志物如抑制素α,ACVR2B,LHR。值得注意的是,整个卵巢切片中p-SMAD3和Ki67的表达不受控制,以及广泛存在的黄体化基质细胞和裂解的Caspase-3阳性垂死细胞。
结论:这些遗传学研究强调了KIT在卵母细胞中对维持卵泡存活和确保生殖寿命不可或缺的作用。
背景:这项工作得到了美国国立卫生研究院拨款R01HD096042和UNMC(S.Y.K.)启动资金的支持。
BACKGROUND: The KITL-KIT interaction is known as an important initiator in oocyte activation through the downstream pathway of PI3K-AKT-FOXO3 signalling. Previous studies utilising germ cell-specific Kit mutant knockin and kinase domain knockout models with Vasa-Cre suggested the crucial role of KIT in oocyte activation at the primordial follicle stage.
METHODS: We utilised mice with complete postnatal deletion of KIT expression in oocytes via Gdf9-iCre and conducted analyses on ovarian follicle development, specific markers, hormone assays, and fertility outcomes.
RESULTS: Our findings reveal contrasting phenotypes compared to previous mouse models with prenatal deletion of Kit. Specifically, postnatal deletion of Kit exhibit no defects in germ cell nest breakdown, follicle activation, and folliculogenesis during development. Remarkably, upon reaching full maturity, mice with postnatal deletion of Kit experience a complete loss of ovarian reserve, growing follicles, and ovarian function. Furthermore, mice display smaller ovarian size and weight, delayed folliculogenesis, and phenotypes indicative of primary ovarian insufficiency (POI), including elevated serum levels of FSH, reduced AMH, and absence of ovarian follicles, ultimately resulting in infertility. Additionally, the ovaries exhibit randomly distributed expression of granulosa and theca cell markers such as Inhibin α, ACVR2B, and LHR. Notably, there is the uncontrolled expression of p-SMAD3 and Ki67 throughout the ovarian sections, along with the widespread presence of luteinised stroma cells and cleaved Caspase-3-positive dying cells.
CONCLUSIONS: These genetic studies underscore the indispensable role of KIT in oocytes for maintaining the survival of ovarian follicles and ensuring the reproductive lifespan.
BACKGROUND: This work was supported by National Institutes of Health grant R01HD096042 and startup funds from UNMC (S.Y.K.).