The Inositol Phosphate Cascade as a Regulator of FSH and LH actions in the Ovary

描述(申请人提供)：促性腺激素诱导颗粒细胞芳香酶的表达依赖于被激活的信号通路，这是由每个促性腺激素受体的密度决定的。我们推测，低密度的促性腺激素受体支持芳香酶的表达，因为只有cAMP和Akt通路被激活，而高密度的促性腺激素受体不支持芳香酶的表达，因为它们还刺激肌醇磷酸和二酰甘油的积累，导致表观调节蛋白的释放和EGFR和ERK1/2的磷酸化。LHR作为芳香酶表达的抑制因子，参与刺激肌醇磷酸酶级联反应的报道仅使用在颗粒细胞原代培养中表达的促性腺激素受体突变体。因此，我们建议使用转基因小鼠模型来确定LHR是否有必要激活卵巢肌醇磷酸级联反应，以下调排卵后芳香酶的表达。目的1建立颗粒细胞特异性缺失GQ/11敏感的肌醇磷酸级联反应的小鼠模型，并鉴定这些小鼠的Gaq和Ga11的表达。AIM 2将确定由AIM 1产生的小鼠的生殖表型。在注射PMSG和hCG的未成熟雌性小鼠中，将定量检测卵巢芳香化酶的表达，以证实我们的假设。我们还将测定未成熟和3~6月龄KO和WT小鼠的血清黄体生成素、卵泡刺激素、雌二醇和孕酮水平。还将分析单独注射PMSG或PMSG和hCG注射的未成熟雌性的卵巢组织学和血清E2和P4浓度。如果我们发现hCG后KO小鼠的芳香酶表达仍然很高(正如预测的那样)，那么我们将使用这些小鼠的颗粒细胞来测量参与芳香酶反应的所提出的信号通路的不同组成部分。不管建议的实验结果如何，让颗粒细胞特异性缺失磷酸肌醇级联的小鼠将使我们能够测试磷酸肌醇级联对卵巢生理的其他潜在作用。 公共卫生相关性：了解FSH/FSHR和LH/LHR对卵巢生理的共同和不同影响，将有助于将FSH和LH/hCG用作不孕症药物，以及它们如何调节控制生殖的主要激素(雌二醇和孕酮)。

DESCRIPTION (provided by applicant): The gonadotropin-induced expression of aromatase in granulosa cells is dependent on the signaling pathways that are activated, which is dictated by the density of each gonadotropin receptor. We hypothesize that low gonadotropin receptor densities support aromatase expression because only cAMP and Akt pathways are activated, while higher gonadotropin receptor densities do not support aromatase expression because they also stimulate the accumulation of inositol phosphates and diacylglycerol leading to the release of epiregulin and phosphorylation of EGFR and ERK1/2. Involvement of LHR to stimulate the inositol phosphate cascade as an inhibitor of aromatase expression has been reported only using gonadotropin receptor mutants expressed in primary cultures of granulosa cells. Therefore, we propose to use genetically modified mouse models to determine if activation of the ovarian inositol phosphate cascade by LHR is necessary for down regulation of aromatase expression that occurs after ovulation. Aim 1 will generate a mouse model with a granulosa cell- specific deletion of the Gq/11-sensitive inositol phosphate cascade and characterize the expression of Gaq and Ga11 of these mice. Aim 2 will determine the reproductive phenotype of mice produced from Aim 1. Ovarian aromatase expression will be quantified in immature female mice injected with PMSG followed by hCG to confirm our hypothesis. We will also measure serum LH, FSH, E2 and P4 of immature and 3 to 6 month old KO and wt mice. Ovarian histology and E2 and P4 serum concentrations of immature females injected with PMSG alone or PMSG and hCG will also be analyzed. If we find that aromatase expression remains high after hCG (as predicted) in the KOmice, we will then use granulosa cells from these mice to measure the different components of the proposed signaling pathway involved in the aromatase response. Regardless of the results of the proposed experiments having mice with a granulosa cell-specific deletion of the inositol phosphate cascade will allow us to test for other potential roles of the inositol phosphate cascade on ovarian physiology. PUBLIC HEALTH RELEVANCE: Understanding common and divergent effects of the FSH/FSHR and LH/LHR pairs on ovarian physiology will aid in the use of FSH and LH/hCG as infertility drugs and how they regulate the major hormones (estradiol and progesterone) that control reproduction.