Cyclic AMP Signaling in Granulosa Cells

描述（由申请人提供）：尽管在了解促卵泡激素（FSH）在控制排卵前卵泡发生过程中的作用方面取得了进展，但仍有一个主要问题未得到解答，即FSH在调节卵泡发育过程中发生的复杂基因表达模式中所利用的细胞内信号通路的阐明。我们的初步结果指出了两个基因座，FSH可能通过这些基因座最佳地诱导颗粒细胞分化。首先，激活除PKA途径外的一条或几条途径与PKA途径协同作用，以最佳方式诱导包括芳香化酶和LH受体在内的一组基因的表达，这两个标志基因与颗粒细胞分化相关。其次，FSH/cAMP信号通路的区室化可能导致细胞内cAMP生成与雌激素和黄体酮生物合成途径的更有效耦合。在当前的建议中，我们提出了四个具体目标来解决这些发现。目的1将比较未分化颗粒细胞中FSH和PKA-CQR激活的信号通路。目的2将确定哪些信号通路和/或转录因子与PKA相互作用，以最佳方式诱导颗粒细胞分化。Aim 3将通过破坏PKA/AKAP与HT31肽在颗粒细胞分化中的相互作用，并使用新型基于fret的PKA传感器直接评估颗粒细胞中cAMP/PKA信号的区隔化，探索颗粒细胞中cAMP/PKA信号系统可能的细胞内区隔化。了解颗粒细胞分化的信号通路可能有助于开发新型避孕药和“生育药物”，并提供有关可能影响卵巢衰竭和多囊卵巢综合征等无排卵障碍的信号通路的新信息。

DESCRIPTION (provided by applicant): Although progress has been made in understanding the role of follicle stimulating hormone (FSH) in governing the process of preovulatory folliculogenesis, a major question that remains unanswered is the elucidation of the intracellular signaling pathways utilized by FSH in the regulation of the complex pattern of gene expression that occurs during follicular development. Our preliminary results point to two loci through which FSH may optimally induce granulosa cell differentiation. First, activation of a pathway or pathways in addition to PKA synergizes with the PKA pathway to optimally induce the expression of a subset of genes including aromatase and the LH receptor, the two hallmark genes associated with granulosa cell differentiation. Second, compartmentalization of the FSH/cAMP signaling pathway may result in more efficient coupling of intracellular cAMP production with the induction of the estrogen and progesterone biosynthetic pathways. In this current proposal we present four Specific Aims to address these findings. Aim 1 will compare the signaling pathways activated by FSH and by PKA-CQR in undifferentiated granulosa cells. Aim 2 will determine which signaling pathways and/or transcription factors interact with PKA to optimally induce granulosa cell differentiation. Aim 3 will explore the possible intracellular compartmentalization of the cAMP/PKA signaling system in granulosa cells by disrupting PKA/AKAP interactions with HT31 peptides on granulosa cell differentiation and using novel FRET-based PKA sensors to directly evaluate compartmentalization of cAMP/PKA signaling in granulosa cells. Understanding the signaling pathways involved in granulosa cell differentiation may be instrumental for the development of novel contraceptives and "fertility drugs" as well as providing new information regarding signaling pathways that may be affected in anovulatory disorders such as ovarian failure and polycystic ovarian syndrome. PUBLIC HEALTH RELEVANCE: This project seeks to identify the cellular mechanisms that control the maturation of the ovarian follicle.