Mechanisms Controlling Divergent Fates of Ovarian Follicles and Fertility

描述(申请人提供)：拟议研究的目标是确定FOXO boxO转录因子、FSH和卵巢衍生生长因子(激活素和BMP2)调节卵泡生长和凋亡从而调节生育的机制。通过有选择地破坏颗粒细胞中的Foxo1和Foxo3基因，我们产生了一种新的表型不同于颗粒细胞中所有其他已知突变的不育小鼠。不孕不育的表型可以追溯到：1)卵泡生长和凋亡减少，这导致我们发现了一种新的范式：FOXO1/3在颗粒细胞中作用于卵泡成熟和凋亡，并且这些不同的功能分别与激活素或BMP2信号通路的特定相互作用密切相关。2)有缺陷的卵母细胞发育，似乎主要是由突变的卵丘细胞发出的代谢/内分泌因素的变化所介导的。对突变小鼠卵丘和卵母细胞功能的分析应该会引导我们发现调控卵母细胞成熟的特定FOXO1/3靶点，以及3)卵巢对脑垂体反馈的变化导致FSH抑制，这似乎是由一种新的卵巢衍生因子介导的，而不是抑制素。表征一种新的FSHB抑制剂(S)对开发替代避孕靶点具有深远的意义。因此，Foxo1/3条件性KO小鼠提供了一个独特的模型，在该模型中可以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一种新的抑制垂体FSHB表达的因子(S)的生理、分子和生化机制。为了分析Foxo1/3控制生殖成功的这些功能，我们提出了以下具体目标：1)确定FSH、激活素、BMP2和FOXO1/3之间的相互作用如何影响完整卵泡中颗粒细胞的凋亡。Ii)确定影响生育能力的Foxo1/3突变小鼠卵丘细胞和卵母细胞功能的变化。Iii)鉴定来源于Foxo1/3突变卵巢的新的FSHB抑制因子(S)。

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.