Defining the Mechanisms involved in Luteolysis

描述（由申请人提供）：黄体（CL）由于分泌黄体酮（哺乳动物怀孕所需的激素）而在生殖生理中起关键作用。然而，如果没有怀孕，淋巴细胞会经历一个有趣的过程，称为黄体溶解，其特征是黄体酮产生减少和淋巴细胞死亡。本研究探讨了体内黄体溶解的机制。细胞内信号通路和基因表达级联与保护或敏感相关的黄体溶解将被定义。首先，将对CL中的转录体（稳态mRNA浓度）进行分析，使用牛微阵列分析大约20,000种不同的mRNA转录物。更系统的分析还将对转录体的变化进行分析，这些变化是由激素引起的黄体溶解，前列腺素F2alpha (PGF)，在有能力进行黄体溶解以响应PGF（黄体溶解能力）的CL或没有黄体溶解能力的CL中诱导的。其次，将验证一个体内模型，该模型产生一个充满液体的大腔，允许腔内治疗和监测。该模型是我们未来研究黄体溶解的核心，因为尽管付出了相当大的努力，但尚未开发出完全模拟体内黄体溶解的体外系统，这使得在黄体溶解过程中有效探索细胞内信号转导变得困难。该体内模型将用于探索可能对卵黄溶解敏感性起核心作用的2个关键细胞内通路。新的假设将探讨组成活性蛋白激酶A （PKA）在高组成孕酮产生中的作用以及PKA在黄体溶解过程中的变化。我们还将研究高黄体内黄体酮“保护”黄体反应不受PGF作用的影响，以及该途径在黄体溶解敏感性中的作用。特异性目的1：表征黄体溶解诱导的CL转录体变化。本研究将利用牛微阵列和差分显示技术，在PGF处理后2次（1小时和10小时），确定PGF在具有和不具有溶血能力的CL中诱导的mRNA的变化。特定目的2：表征一种用于牛肠腔内治疗的体内模型。特定目的3：确定PKA在黄体功能和黄体溶解能力中的作用。研究将探讨PKA如何参与高黄体黄体酮和黄体溶解能力。特定目的4：确定卵泡内黄体酮在卵泡溶解能力中的作用。本研究的完成将验证一种新的体内模型，并为黄体溶解过程中特定基因表达级联和信号转导途径的相互作用提供见解。

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.