Defining the Mechanisms involved in Luteolysis

描述（由申请人提供）：黄体（CL）由于分泌孕酮（哺乳动物妊娠所需的激素）而在生殖生理学中起关键作用。然而，如果没有发生妊娠，CL会经历一个有趣的过程，称为黄体溶解，其特征是孕酮产生减少和CL细胞死亡。本研究探讨了黄体溶解的体内机制。与黄体溶解保护或致敏相关的细胞内信号传导途径和基因表达级联将被定义。首先，使用牛微阵列分析约20，000种不同的mRNA转录物，对CL中的转录体（稳态mRNA浓度）进行分析。还将对引起黄体溶解的激素前列腺素F2 α（PGF）诱导的转录体变化进行更系统的分析，在CL中有能力对PGF（黄体溶解能力）做出反应而发生黄体溶解，或在CL中没有黄体溶解能力。其次，将对体内模型进行确认，该模型可产生具有大液体填充腔的CL，允许进行输卵管内治疗和监测。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，这使得难以有效地探索黄体溶解过程中的细胞内信号转导。该体内模型将用于探索可能对黄体溶解敏感性至关重要的2种关键细胞内途径。新的假说将探讨组成性活性蛋白激酶A（PKA）在高组成性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孕酮对PGF作用的“保护”黄体反应以及该途径在黄体溶解敏感性中的作用。特定目的1：表征黄体溶解诱导的CL转录体变化。本研究利用牛源性前列腺素微阵列技术和差异显示技术，研究前列腺素F处理后2个时间点（1 h和10 h），前列腺素F诱导的有和无黄体溶解能力的CL中mRNA的变化。特定目标2：表征牛CL输卵管内治疗的体内模型。具体目的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如何参与高黄体孕酮和黄体溶解能力。具体目的4：确定黄体内孕酮在溶黄体能力中的作用。这项研究的完成将验证一个新的体内模型，黄体溶解，并提供特定的基因表达级联反应和信号转导通路在黄体溶解过程中的相互作用的见解。

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.