A Novel Function of the Oocyte in Estrogen-Regulated FSH Action

描述（由申请人提供）：在女性中，与年龄相关的卵巢储备减少最不利影响的功能之一是生育力下降。这种与年龄相关的变化的基础是优势卵泡不能释放出可以进行正常胚胎发育的卵子。目前的想法是，促卵泡刺激素作用的增加与36岁以后妇女生育能力下降的机制有关。这项拨款在了解促卵泡刺激素作用机制方面取得了令人兴奋的进展。利用大鼠模型，我们最近发现卵母细胞在增强颗粒细胞中FSH作用的雌激素活性中是必不可少的。我们还发现雌激素和卵母细胞的协同作用发生在FSH受体的下游和腺苷酸环化酶的上游。进一步的研究提供了G蛋白偶联受体激酶(GRK)/？-颗粒细胞中存在的抑制系统。此外，我们证明了GRK-6仅在卵母细胞存在时被雌激素选择性抑制，这表明雌激素和卵母细胞通过阻止GRK-6/？-抑制素介导的生物作用，包括FSH诱导的G蛋白信号的脱敏和丝裂原激活的蛋白激酶信号转导的激活。在这个R21拨款提案中，我们将阐明卵母细胞在介导雌激素对颗粒细胞FSH敏感性的作用中发挥强制性作用的分子机制。在目标1中，我们将检验我们的假设，即GRK-6/？-抑制素系统参与了雌激素-卵母细胞共处理增强FSH作用的机制。我们还将首次提供卵巢GRK/？-抑制素系统，该系统与FSH受体活性的调节有关。在Aim 2中，我们将剖析雌激素作用所需的卵母细胞和颗粒细胞之间的通信网络，并探讨卵母细胞和颗粒细胞如何通信以使雌激素刺激FSH作用。此外，我们将利用蛋白质组学和基因芯片确定在雌激素存在的情况下，在卵母细胞和颗粒细胞之间的通讯网络中起作用的因子，以增强FSH的作用。微阵列分析。该项目将通过引入GRK/？这可能会在开发治疗卵巢功能障碍的药理学方案方面取得突破，特别是在老年妇女中。公共卫生相关性：促卵泡激素（FSH）是卵巢功能的重要激素，包括卵泡发育和排卵。我们最近发现，雌激素增强卵泡细胞中卵泡刺激素的作用，而不是没有卵母细胞。提出的研究旨在阐明这一发现的分子和细胞机制，这可能导致开发治疗卵巢功能障碍的药物方案，特别是在老年妇女中。

DESCRIPTION (provided by applicant): In women, one function most adversely affected by the age-related decrease in ovary reserve is decreased fecundity. The basis for this age-related change is the failure of dominant follicles to release eggs that can undergo normal embryonic development. The current thinking is that increased FSH action is involved in the mechanisms underlying decreased fecundity in women after 36 years of age. This grant represents an exciting advance in understanding the mechanisms of FSH action. Using the rat model, we have recently discovered that the oocyte is essential for estrogen activity in enhancing FSH action in granulosa cells. We have also found that the synergistic action of estrogen and oocytes occurs at a site downstream of the FSH receptor and upstream of adenylate cyclase. Further studies have provided the first evidence for a functional G protein-coupled receptor kinase (GRK)/?-arrestin system present in granulosa cells. Moreover, we demonstrate that GRK-6 is selectively suppressed by estrogen only in the presence of oocytes, suggesting that estrogen and oocytes synergistically enhance FSH action by preventing GRK-6/?-arrestin-mediated biological actions including desensitization of G protein signaling and activation of mitogen-activated protein kinase signal transduction induced by FSH. In this R21 grant proposal, we will elucidate the molecular mechanisms by which the oocyte plays an obligatory role in mediating estrogen action on the FSH sensitivity of granulosa cells. In Aim 1, we will test our hypothesis that the GRK-6/?-arrestin system is involved in the mechanism by which estrogen-oocyte co-treatment enhances FSH action. We will also provide the first comprehensive analysis of the ovarian GRK/?-arrestin system, which has been implicated in the mediation of the FSH receptor activity. In Aim 2, we will dissect the communication network between the oocyte and granulosa cell that is required for estrogen action and explore how oocytes and granulosa cells communicate in order for estrogen to stimulate FSH action. Moreover, we will identify the factor(s) that acts in the communication network between oocytes and granulosa cells to augment FSH action in the presence of estrogen, using proteomics and GeneChip. microarray analyses. The proposed project should provide a novel conceptual framework for understanding the molecular and cellular mechanisms of estrogen action in mammalian ovaries by introducing the GRK/?-arrestin system into the ovarian physiology and may lead a breakthrough in developing pharmacological regimens for treating ovarian dysfunctions, particularly in aging women. PUBLIC HEALTH RELEVANCE: Follicle-stimulating hormone (FSH) is an essential hormone for the ovarian function that includes follicle development and ovulation. We have recently discovered that estrogen enhances FSH action in follicular cells in the presence, but not absence, of oocytes. The proposed studies aim to elucidate the molecular and cellular mechanisms of this finding, which may lead to develop pharmaceutical regimens for treating ovarian dysfunctions, particularly in aging women.