Progesterone regulation of human luteal cell viability

描述（由申请人提供）：核黄体酮受体（nPRs） PR-A和PR-B在人黄体细胞中表达。此外，黄体酮（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nPRs介导其抗凋亡作用。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功能。此外，黄体细胞表达了几种膜受体或P4作用的介质。由于生殖过程需要对黄体细胞活力进行精确调节，因此我们必须确定在人类黄体细胞中哪种受体或受体介导P4的抗凋亡作用。我们不应该接受P4仅通过nPR介导其抗凋亡作用的概念，因为这一假设仅基于nPR表达和药理学研究。因此，我们将使用遗传方法来调节培养的人类黄体细胞中nPRs的水平，然后评估P4防止黄体细胞凋亡的能力。我们提出了以下三个具体目标：1)从P4分泌和nPR的表达以及P4作用的其他潜在介质的角度来表征人黄体细胞的体外分化和退化；2) P4维持人黄体细胞活力的能力与nPRs和其他P4介质的表达之间的关系；3)确定特异性消融和nPRs过表达对P4促进黄体细胞活力的影响。如果研究表明P4的抗凋亡活性不完全由nPRs介导，那么一种或多种其他潜在的P4介质可能参与了P4的抗凋亡作用的转导。如果是这样，这可能会开辟新的药理学领域，将直接抑制或增强这些其他P4介质的作用。由于其中三种候选蛋白质的结构与nPRs的结构非常不同，因此可能开发出影响其作用而不干扰nPRs作用的药物。这种选择性操纵P4的行为可能对治疗不孕症、避孕和某些类型的癌症产生深远的影响。

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.