Defining the Mechanisms involved in Luteolysis

描述(申请人提供)：黄体(CL)在生殖生理中起关键作用，因为分泌孕酮，这是哺乳动物怀孕所必需的荷尔蒙。然而，如果没有怀孕，CL会经历一个有趣的过程，称为黄体溶解，其特征是黄体酮的产生减少和CL中细胞的死亡。这项研究探索了黄体溶解的体内机制。与黄体溶解的保护或敏化相关的细胞内信号通路和基因表达级联将被定义。首先，将使用牛微阵列对大约20,000个不同的mRNA转录本进行分析，以分析CL中的转录体(稳态mRNA浓度)。对引起黄体溶解的激素前列腺素F2pha(PGF)引起的转录体的变化也将进行更系统的分析，在有能力进行黄体溶解的CL中或在没有黄体溶解能力的CL中。其次，体内模型将得到验证，该模型产生的CL具有一个大的充满液体的空腔，允许进行子宫内治疗和监测。这个模型是我们未来黄体溶解研究的核心，因为尽管我们做了相当多的努力，但还没有开发出完全模拟体内黄体溶解的体外系统，这使得有效地探索黄体溶解过程中的细胞内信号转导变得困难。这个体内模型将被用来探索两条关键的细胞内途径，这两条途径可能是黄体溶解敏感性的中心。新的假说将探索结构性活性蛋白激酶A(PKA)在高组成性孕酮产生中的作用以及在黄体溶解过程中PKA的变化。我们还将研究高黄体内孕酮“保护”黄体不受PGF作用的黄体反应，以及这一途径在黄体溶解敏感性中的作用。具体目标1：确定黄体溶解引起的CL转录体的变化。本研究将利用牛基因芯片和差异显示技术，检测PGF处理后2次(1h和10h)有和无黄体溶解能力的CL中PGF诱导的mRNA表达的变化。具体目标2：描述黄体内治疗牛CL的体内模型。具体目标3：确定PKA在黄体功能和黄体溶解能力中的作用。研究将探索PKA如何参与高黄体酮和黄体溶解能力。具体目标4：确定黄体内孕酮在黄体溶解能力中的作用。这项研究的完成将验证一种新的体内黄体溶解模型，并为深入了解黄体溶解过程中特定基因表达级联和信号转导途径之间的相互作用提供依据。

DESCRIPTION (provided by applicant): The corpus luteum (CL) has a critical role in reproductive physiology due to secretion of progesterone, a hormonal requirement for pregnancy in mammals. However, if pregnancy does not occur, CL undergo an intriguing process termed luteolysis that is characterized by decreased progesterone production and death of cells in the CL. This research explores the in vivo mechanisms of luteolysis. The intracellular signaling pathways and gene expression cascades associated with protection or sensitization to luteolysis will be defined. First, an analysis will be done of the transcriptosome (steady state mRNA concentrations) in the CL using bovine microarray analysis of about 20,000 different mRNA transcripts. A more systematic analysis will also be performed of the changes in the transcriptosome that are induced by the hormone causing luteolysis, prostaglandin F2alpha (PGF), in CL that have the ability to undergo luteolysis in response to PGF (luteolytic capacity) or in CL without luteolytic capacity. Second, an in vivo model will be validated that produces CL with a large fluid-filled cavity allowing intraluteal treatments and monitoring. This model is central to our future studies of luteolysis because, despite considerable effort, no in vitro system has been developed that fully mimics in vivo luteolysis making it difficult to validly explore intracellular signal transduction during luteolysis. This in vivo model will be used to explore 2 key intracellular pathways that may be central to luteolytic sensitivity. Novel hypotheses will be explored on the role of constitutively active protein kinase A (PKA) in high constitutive progesterone production and the changes in PKA during luteolysis. We will also examine the luteal responses "protected" from PGF action by high intraluteal progesterone and the role of this pathway in luteolytic sensitivity. SPECIFIC OBJECTIVE 1: Characterize luteolysis-induced changes in the transcriptosome of the CL. This Objective will use bovine microarrays and differential display to determine the changes in mRNA that are induced by PGF in CL with and without luteolytic capacity at 2 times after PGF treatment (1 h and 10 h). SPECIFIC OBJECTIVE 2: Characterize an in vivo model for intraluteal treatment of bovine CL. SPECIFIC OBJECTIVE 3: Determine the roles of PKA in luteal function and luteolytic capacity. Studies will explore how PKA may be involved in high luteal progesterone and luteolytic capacity. SPECIFIC OBJECTIVE 4: Determine the role of intraluteal progesterone in luteolytic capacity. Completion of this research will validate a new in vivo model for luteolysis and provide insight into the interactions of specific gene expression cascades and signal transduction pathways during luteolysis.