Progesterone regulation of human luteal cell viability

描述(申请人提供)：核孕酮受体(NPR)PR-A和PR-B在人黄体细胞中均有表达。此外，孕酮(P4)抑制和NPR拮抗剂RU486诱导人黄体细胞凋亡(即程序性细胞死亡)。这些观察结果表明，P4通过激活NPR介导其抗细胞凋亡作用。然而，最近的研究表明，P4通过基因组和非基因组机制调节黄体细胞的功能。此外，黄体细胞还表达几种膜受体或P4‘S作用的中介物质。由于黄体细胞活力的精确调控是生殖过程所必需的，因此我们有必要确定是哪个或哪些受体介导了人黄体细胞中P4‘S的抗凋亡作用。我们不应该接受P4完全通过NPR介导其抗凋亡作用的概念，因为这一假设完全建立在NPR表达和药理学研究的基础上。因此，我们将使用遗传学方法来调节培养的人黄体细胞中NPR的水平，然后评估P4‘S阻止黄体细胞凋亡的能力。我们提出以下三个具体目标：1)从P4的分泌和NPR的表达以及P4‘S作用的其他潜在介质的角度来表征人黄体细胞的分化和退化；2)将P4维持黄体细胞活性的能力与NPR和其他P4介质的表达相关联；以及3)确定NPR的特异性消融和过度表达对P4促进黄体细胞活性能力的影响。如果研究表明P4‘S的抗凋亡作用不是完全由NPR介导的，那么其他一个或多个潜在的P4介体可能参与转导P4’S的抗凋亡作用。如果是这样的话，这可能会开辟新的药理学领域，旨在抑制或增强这些其他P4介体的作用。由于其中三种候选蛋白质的结构与NPR的结构非常不同，因此有可能开发出在不干扰NPR的作用的情况下影响其作用的药物。这种对P4‘S活动的选择性操纵可能会对不孕不育、避孕和某些类型的癌症的治疗产生深远的影响。

DESCRIPTION (provided by applicant): Both nuclear progesterone receptors (nPRs), PR-A and PR-B, are expressed in human luteal cells. Further, progesterone (P4) inhibits and the nPR antagonist, RU486, induces human luteal cell apoptosis (i.e., programmed cell death). These observations suggest that P4 mediates its antiapoptotic action by activating the nPRs. However, recent studies have shown that P4 modulates luteal cell function by both genomic and non-genomic mechanisms. Moreover, several membrane receptors, or mediators of P4's action, are expressed by luteal cells. Since the precise regulation of luteal cell viability is required for the reproductive process, it is essential that we determine which receptor, or receptors, mediates P4's antiapoptotic action in human luteal cells. We should not accept the concept that P4 mediates its antiapoptotic action exclusively through the nPRs, since this assumption is based solely on nPR expression and pharmacological studies. Therefore, we will use genetic approaches to modulate the levels of nPRs in cultured human luteal cells and then assess P4's ability to prevent luteal cell apoptosis. We propose the following three specific aims: 1) to characterize human luteal cell differentiation and regression in vitro in terms of P4 secretion and expression of nPR as well as other potential mediators of P4's action; 2) to correlate the ability of P4 to maintain the viability of human luteal cells with the expression of the nPRs and other P4 mediators; and 3) to determine the effect of specific ablation and over expression of the nPRs on the ability of P4 to promote luteal cell viability. If the studies indicate that P4's antiapoptotic activity is not exclusively mediated by the nPRs, then one or more of the other potential P4 mediators could be involved in transducing P4's antiapoptotic action. If so, this could open up new areas of pharmacology that would be directed toward inhibiting or enhancing the action of these other P4 mediators. Since the structures of three of these candidate proteins are very different from that of the nPRs, drugs could potentially be developed that influence their action without interfering with the action of the nPRs. Such selective manipulation of the P4's actions could have far reaching effects on the treatment for infertility, contraception and certain types of cancers.