Mechanisms Controlling Divergent Fates of Ovarian Follicles and Fertility

描述（由申请人提供）：本研究的目的是确定FOXO boxO转录因子、FSH和卵巢衍生生长因子（激活素和BMP 2）调节卵巢卵泡生长和凋亡以及生育力的机制。通过在颗粒细胞中选择性地破坏Foxo 1和Foxo 3基因，我们已经产生了不育小鼠，其具有不同于颗粒细胞中所有其他已知突变的新表型。不孕表型可以追溯到：1）卵泡生长和凋亡减少，导致我们发现了一个新的范例：FOXO 1/3在颗粒细胞中起作用，介导卵泡成熟和凋亡，FOXO 1/3的这些不同功能分别与激活素或BMP 2信号通路的特异性相互作用密切相关。2)卵母细胞发育缺陷，似乎主要由突变卵丘细胞产生的代谢/内分泌因子的变化介导。对突变小鼠卵丘和卵母细胞功能的分析应使我们发现调节卵母细胞成熟的特异性FOXO 1/3靶点; 3）卵巢对垂体的反馈改变，导致FSH受抑制，这似乎是由一种新的卵巢衍生因子介导的，而不是卵泡刺激素。表征一种新的Fshb抑制剂对开发替代避孕目标具有深远的影响。因此，Foxo 1/3条件性KO小鼠提供了一种独特的模型，其中确定这些转录调节因子影响细胞凋亡、卵母细胞成熟和卵巢产生抑制垂体Fshb表达的新因子的生理、分子和生化机制。为了分析Foxo 1/3控制生殖成功的这些功能，我们提出了以下具体目标：I）确定FSH、激活素、BMP 2和Foxo 1/3之间的相互作用如何影响完整卵泡中的颗粒细胞凋亡。II）确定影响生育力的Foxo 1/3突变小鼠中卵丘细胞和卵母细胞功能的变化。III）表征源自Foxo 1/3突变卵巢的新Fshb抑制因子。

DESCRIPTION (provided by applicant): The goal of the proposed research is to determine the mechanisms by which the FOXO boxO transcription factors, FSH and ovarian---derived growth factors (activin and BMP2) regulate ovarian follicular growth and apoptosis and hence fertility. By disrupting the Foxo1 and Foxo3 genes selectively in granulosa cells, we have generated mice that are infertile with a novel phenotype that is distinct from all other known mutations in granulosa cells. The infertile phenotype can be traced to: 1) Reduced follicle growth and apoptosis leading us to discover a new paradigm: that FOXO1/3 act in granulosa cells to mediate both follicle maturation and apoptosis, and that these distinct functions of FOXO1/3 are tightly linked to specific interactions with either the activin or BMP2 signaling pathways, respectively. 2) Defective oocyte development that appears to be mediated primarily by changes in metabolic/endocrine factors emanating from the mutant cumulus cells. Analyses of cumulus and oocyte functions in the mutant mice should lead us to discover specific FOXO1/3 targets that regulate of oocyte maturation and 3) Alterations in ovarian feedback to the pituitary leading to suppressed FSH that appears to be mediated by a novel ovarian---derived factor that is not inhibin. Characterizing a new Fshb suppressor(s) has far---ranging implications for developing alternative contraceptive targets. Thus, the Foxo1/3 conditional KO mice provide a unique model in which to determine the physiological, molecular and biochemical mechanisms by which these transcriptional regulators impact apoptosis, oocyte maturation and ovarian production of a novel factor(s) that suppresses pituitary Fshb expression. To analyze these functions of Foxo1/3 that control reproductive success, we propose the following Specific Aims: I) Determine how interactions between FSH, activin, BMP2 and FOXO1/3 impact granulosa cell apoptosis in intact follicles. II) Determine the changes in cumulus cell and oocyte functions in the Foxo1/3 mutant mice that impact fertility. III) Characterize the novel Fshb inhibitory factor(s that emanate from the Foxo1/3 mutant ovaries.