PDE3 Inhibitors: Selective Blockers of Oocyte Maturation

描述（由申请人提供）：避孕的需求从未像现在这样大，世界人口超过60亿，目前有超过10亿的年轻人处于最佳生育年龄。人口过剩是一种有害的公共卫生问题，它破坏了基础设施，威胁到人类的基本基础设施，限制了在总体健康状况方面取得来之不易的成果。避孕还通过减少意外怀孕、堕胎和意外生育提供了显著的预防性健康益处。由于副作用、获取途径以及文化或道德上的反对限制了当前避孕方法的普遍接受，因此有必要研究新的避孕方法。本基金的目的是探索灵长类动物卵巢中存在选择性表达磷酸二酯酶（POE）异构体的假设，PDE3的选择性阻断可以用来阻止自发和促性腺激素诱导的卵母细胞成熟，以及PDE3抑制剂的慢性治疗可以在不影响月经周期或黄体功能的情况下预防灵长类动物怀孕。具体目的是：(1)描述PDE在灵长类动物卵巢中的基本生物学表达。目的是表征PDE同工酶在猕猴卵巢中的表达。另一个目标将是测试新的PDE3抑制剂在体外防止减数分裂自发恢复的能力，以了解是否可以实现更高的选择性或效力。(2)确定PDE3抑制剂是否在体内进行可控卵巢刺激（COS）或自然周期的恒河猴中阻止卵母细胞成熟，但不阻止排卵和黄体功能。本研究的目的是证明卵母细胞抑制可以在体内有效和选择性地实现，并研究PDE3抑制剂在体内的药理学活性剂量的全身毒性。3)确定PDE3抑制剂在定期循环的恒河猴配对交配情况下是否具有避孕作用。本研究的目的是通过长期观察来证明PDE3抑制剂作为一种潜在的避孕药物的有效性和实用性。实验设计将包括：鉴定卵巢组织体细胞和生殖细胞中的PDE基因产物（mRNA和蛋白）（目的1），用PDE3抑制剂体外培养未成熟卵母细胞和颗粒细胞（目的1），在COS和自然月经周期期间给猴体内给药PDE3抑制剂，然后通过卵泡抽吸评估卵母细胞体外成熟和受精能力，以及内分泌和毒性测量（目的2）。以及将PDE 3抑制剂长期施用于育龄雌性和育龄雄性，以评估避孕效果和长期毒性（目的3）。该方法有望为未来PDE3抑制剂的人体i期试验奠定基础。

DESCRIPTION (provided by applicant): The need for contraception has never been greater, as evidenced by a world population of over 6 billion, and greater than one billion young people currently in the prime reproductive years. Overpopulation is a pernicious public health affliction that ravages infrastructure and limits the achievement of hard fought gains in overall health status by threatening the basic infrastructure of humanity. Contraception also provides significant preventative health benefits by reducing unintended pregnancy, abortions, and unwanted births. As side effects, access, and cultural or moral objections limit the universal acceptance of current methods, research into novel contraceptives is warranted. The purpose of this grant is to explore the hypotheses that selective expression of phosphodiesterase (POE) isoforms exists in the primate ovary, that selective blockade of PDE3 can be exploited to prevent spontaneous and gonadotropin induced oocyte maturation, and that chronic treatment with a PDE3 inhibitor can prevent pregnancy in primates without affecting menstrual cyclicity or luteal function. The Specific Aims are to: (1) Describe the basic biology of PDE expression in the primate ovary. The goal of this aim is to characterize the PDE isoenzymes expressed in the macaque ovary. An additional goal will be to test novel PDE3 inhibitors for their ability to prevent spontaneous resumption of meiosis in vitro to learn if greater selectivity or potency can be achieved. (2) Determine if PDE3 inhibitors prevent oocyte maturation, but not ovulation and function of the corpus luteum in rhesus monkeys undergoing controlled ovarian stimulation (COS) protocols or during natural cycles in vivo. The goals of this aim will be to document that oocyte inhibition can be effectively and selectively achieved in vivo, and to investigate the systemic toxicity of PDE3 inhibitors at pharmacologically active dosages in vivo. 3) Determine whether PDE3 inhibitors function as contraceptive agents in regularly cycling rhesus monkeys in paired mating situations. The goal of this aim is to document the efficacy and practicality of systemic administration of a PDE3 inhibitor as a potential contraceptive through longer-term observation. Experimental designs will include: characterization of PDE gene products (mRNA and protein) in somatic and germ cells from ovarian tissue (Aim 1), in vitro incubation of immature oocytes and granulosa cells with PDE3 inhibitors (Aim 1), in vivo administration of a PDE3 inhibitor to monkeys during COS and spontaneous menstrual cycles, followed by follicular aspiration to assess oocyte maturation and fertilizability in vitro, plus endocrine and toxicity measurements (Aim 2), and chronic administration of a PDE 3 inhibitor to fertile females caged with fertile males to assess contraceptive efficacy and long term toxicity (Aim 3). This approach is expected to provide a foundation for future Phase 1 trials of PDE3 inhibitors in humans.