FUNCTIONAL ANALYSIS OF AGE-SPECIFIC FSH ANALOGS USING GENETICALLY ALTERED MICE

本项目的长期目标是研究垂体控制女性卵巢衰老的机制。 正常的卵巢功能依赖于卵泡刺激素（FSH），一种垂体衍生的异二聚体 由α和β亚基组成的糖蛋白。这两个亚基都是糖基化的，每个亚基中有两条链 亚单位这种常见的FSH形式称为四糖基化FSH。糖基化在分泌中起主要作用， FSH的血清半衰期和生物学作用。已知垂体促性腺激素的糖基化也是 发情/月经周期-和年龄特异性。生物化学和生理学研究已经发现， 物种是一种独特的二糖基化变体，仅在a亚基而不是p亚基中由糖链组成。最 重要的是，发现四糖基化FSH和二糖基化FSH的比例是年龄依赖性的， 二糖基化变体主要存在于绝经后妇女中。然而，不同的体内生物学 这些FSH变体的功能在正常卵巢生理学中是未知的。假设是一种更有效的 双糖基化FSH是卵泡发生的最佳刺激所必需的，但在老化的卵巢中不是。这 假设将在三个特定目的的基因工程小鼠模型中进行测试。在目标1中，我们将测试 使用FSHp敲除小鼠的来自不同年龄妇女的生化纯化的FSH变体的体内效力。 在目标2中，我们将生产在促性腺激素细胞中定向表达该变体的转基因小鼠， 将该转基因导入FSHp缺失的遗传背景中，以测试二糖基化的FSHp的生物学作用。 变量。在目标3中，我们将暂时调节双糖基化FSH变体的表达（基因开关）， FSHp空背景和鉴定二糖基化变体的年龄特异性生物学效应。 用上述遗传模型进行功能分析将鉴定FSH变体的不同生物学作用 在卵巢老化过程中的体内。女性和其他物种的卵巢卵泡储备随着年龄的增长而减少， 这直接影响卵母细胞的质量。因此，我们的研究将对制定新的 用于增强老年妇女健康卵泡和卵母细胞的产生的治疗。

The long-term goal of this project is to study mechanisms of pituitary control of ovarian aging in women. Normal ovarian function is dependent on follicle-stimulating hormone (FSH), a pituitary derived heterodimeric glycoprotein consisting of an a and a p subunit. Both the subunits are glycosylated with two chains in each subunit. This common FSH form is called tetra-glycosylated FSH. Glycosylation plays a major role in secretion, serum half-life and biological actions of FSH. It is known that glycosylation of pituitary gonadotropins is also estrous/menstrual cycle- and age-specific. Biochemical and physiological studies have identified in several species a unique di-glycosylated variant consisting of sugar chains only in the a but not p subunits. Most importantly, the ratio of tetra- and di-glycosylated FSH is found to be age-dependant, with low levels of di-glycosylated variant predominantly present in post-menopausal women. However, the distinct in vivo biological functions of these FSH variants are unknown in normal ovarian physiology. The hypothesis is that a more potent di-glycosylated FSH is required for optimal stimulation of foliiculogenesis, but not in the aging ovary. This hypothesis will be tested in genetically engineered mouse models in three specific Aims. In Aim 1, we will test the in vivo potencies of biochemically purified FSH variants from different ages of women using FSHp knockout mice. In Aim 2, we will produce transgenic mice with a directed expression of this variant in gonadotropes and introduce this transgene into FSHp null genetic background, to test the biological actions of di-glycosylated variant. In Aim 3, we will temporally regulate the expression (gene switch) of the di-glycosylated FSH variant on a FSHp null background and identify the age-specific biological effects of di-glycosylated variant. Functional analyses with the above genetic models will identify distinct biological actions of FSH variants in vivo during ovarian aging. Ovarian follicle reserve diminishes with aging in women as well as other species and this directly affects the oocyte quality. Therefore, our studies will have a direct clinical impact in formulating new treatments for enhancing the production of healthy follicles and oocytes in aging women.