Developmental Gene-Environment Interactions and Premature Ovarian Failure

描述（由申请人提供）：超过150万活着的美国妇女在其一生中已经或将被诊断为卵巢早衰。卵巢早衰的特点是卵巢卵泡加速衰竭和卵母细胞质量下降。虽然已经确定了卵巢早衰的一些遗传和环境原因，但90%的病例的原因仍然未知。我们之前的研究表明，活性氧是促性腺激素停用或化学毒物如多环芳烃（PAHs）引起的卵泡凋亡的关键信号，补充主要抗氧化剂谷胱甘肽（GSH）具有保护作用。我们的初步数据显示，GSH合成不足的转基因小鼠会发生卵巢早衰，卵巢卵泡加速衰竭，卵母细胞质量差。在卵巢发育期间暴露于多环芳烃会导致啮齿动物卵巢早衰。谷胱甘肽对多环芳烃代谢产物和多环芳烃代谢过程中产生的活性氧的解毒很重要。本研究旨在验证以下假设：GSH基因缺乏通过增加卵泡、卵母细胞和着床前胚胎中的活性氧和氧化损伤导致卵巢早衰，从而导致细胞程序性死亡；胚胎GSH缺乏通过增加多环芳烃代谢相关的活性氧导致子宫内暴露于多环芳烃导致的卵巢早衰，从而启动卵原细胞程序性死亡。具体目的是：(1)在遗传性谷胱甘肽缺乏症小鼠模型中，研究活性氧和氧化损伤在卵巢过早卵泡衰竭和卵母细胞质量差中的作用。活性氧在调节细胞死亡和增殖途径中的作用将在体内和体外卵巢卵泡和胚胎中进行研究。(2)利用颗粒细胞特异性和卵母细胞特异性GSH缺乏的条件敲除小鼠模型，描述颗粒细胞或卵母细胞特异性GSH合成缺陷对卵巢早衰的影响。(3)探讨谷胱甘肽缺乏对PAH苯并[a]芘经胎盘诱导卵巢程序性细胞死亡和卵巢早衰的影响。拟议的研究将确定卵巢关键抗氧化剂谷胱甘肽的遗传缺陷，单独或与子宫内接触苯并[a]芘联合导致卵巢早衰的机制。这些研究将具有更广泛的意义，因为类似的机制可能涉及由其他原因引起的卵巢早衰。了解这些机制对于制定预防卵巢早衰的干预措施非常重要。

DESCRIPTION (provided by applicant): More than 1.5 million of the American women alive today have been or will be diagnosed with premature ovarian failure during their lifetimes. Premature ovarian failure is characterized by accelerated depletion of ovarian follicles and decreased oocyte quality. Although a few genetic and environmental causes of premature ovarian failure have been identified, the causes remain unknown in 90% of cases. Our previous work showed that reactive oxygen species serve as key signals of apoptotic death of ovarian follicles caused by withdrawal of gonadotropins or by chemical toxicants, like polycyclic aromatic hydrocarbons (PAHs), and that supplementation of the major antioxidant glutathione (GSH) is protective. Our preliminary data show that genetically modified mice deficient in GSH synthesis develop premature ovarian failure, with accelerated depletion of ovarian follicles and poor oocyte quality. Exposure to PAHs during ovarian development causes premature ovarian failure in rodents. GSH is important for detoxification of PAH metabolites and of reactive oxygen species produced during PAH metabolism. This proposal aims to test the hypothesis that a genetic deficiency of GSH causes premature ovarian failure by increasing reactive oxygen species and oxidative damage in follicles, oocytes, and preimplantation embryos, leading to programmed cell death, and that embryonic GSH deficiency sensitizes to premature ovarian failure caused by in utero exposure to PAHs by increasing PAH metabolism-related reactive oxygen species that initiate programmed cell death of oogonia. The specific aims are: (1) To examine the roles of reactive oxygen species and oxidative damage in premature ovarian follicle depletion and poor oocyte quality in a mouse model of genetic GSH deficiency. The roles of reactive oxygen species in modulating cell death and proliferation pathways will be examined in vivo and in vitro in ovarian follicles and embryos. (2) To delineate the effects of deficient GSH synthesis localized to granulosa cells or oocytes on premature ovarian failure utilizing conditional knockout mouse models with granulosa cell- and oocyte-specific GSH deficiency. (3) To investigate the effects of GSH deficiency on transplacental induction of ovarian programmed cell death and premature ovarian failure by the PAH benzo[a]pyrene. The proposed studies will define the mechanisms by which genetic deficiency in the key ovarian antioxidant GSH, alone or in combination with in utero exposure to benzo[a]pyrene, causes premature ovarian failure. These studies will have broader implications because similar mechanisms may be involved in premature ovarian failure due to other causes. Understanding these mechanisms is important to developing interventions for the prevention of premature ovarian failure.