Role of LH-induced cell migration and cofilin dephosphorylation in ovulation

项目摘要： 在卵巢中，黄体生成素(LH)通过黄体生成素受体(LHR)发出信号，启动 从排卵前卵泡到黄体的过渡。这种转变的关键是卵母细胞的运动。 至排卵部位，基底板破裂，颗粒细胞重组形成体部 黄体。促黄体生成素受体表达的细胞在促黄体生成素刺激后向内迁移。 在HA-LHR高表达的区域，基板被向内拉。这些结果导致了 促黄体生成素诱导颗粒细胞迁移有助于调节排卵前卵泡向 黄体。先前在分离的颗粒细胞中的研究表明，黄体生成素信号干扰肌动蛋白以 允许细胞骨架重排，并诱导颗粒细胞运动。这些行动的一个潜在调解人是 Cofilin，一种肌动蛋白解聚蛋白。在多种细胞类型中，定向细胞运动需要粘附素活性， 在颗粒细胞中以显性-阴性形式表达该蛋白可抑制黄体生成素诱导的肌动蛋白 重组。然而，Cofilin去磷酸化在体内的作用还有待研究。这个项目 研究了黄体生成素通过cofilin去磷酸化诱导细胞迁移的假说，以及 在排卵期间，迁移将基膜向内拉，以帮助破裂，并重新组织细胞以开始 黄体形成。在目标1中，将使用活组织共聚焦和双光子显微镜来分析 颗粒细胞在完整卵泡中的迁移以及颗粒细胞迁移对基底板的影响 内陷和排卵。在目标二中，一个表达显性-负性cofilin形式的新型小鼠品系 将被用来探索Cofilin去磷酸化调节颗粒细胞迁移的假设。这些 研究将提供有关排卵调节的新信息，并可能导致临床治疗 无排卵性疾病。

Project Abstract: In the ovary, luteinizing hormone (LH) signals through the luteinizing hormone receptor (LHR) to initiate the transition from preovulatory follicle to corpus luteum. Essential to this transition are the movement of the oocyte to the site of ovulation, basal lamina breakdown, and reorganization of the granulosa cells to form the corpus luteum. LHR-expressing cells migrate inwards in response to LH and at later time points after LH stimulation, the basal lamina is pulled inwards in regions of high HA-LHR expression. These results have led to the hypothesis that LH-induced granulosa cell migration aids in regulating the transition from preovulatory follicle to corpus luteum. Previous studies in isolated granulosa cells have indicated that LH signaling disrupts actin to allow cytoskeletal rearrangement and induces granulosa cell motility. One potential mediator of these actions is cofilin, an actin-depolymerizing protein. Cofilin activity is required for directional cell motility in multiple cell types, and expression of a dominant-negative form of the protein in granulosa cell inhibits LH-induced actin reorganization. However, the role of cofilin dephosphorylation in vivo has yet to be investigated. This project investigates the hypothesis that LH induces cell migration through dephosphorylation of cofilin, and that the migration pulls the basal lamina inward to aid in rupture during ovulation and reorganizes the cells to begin corpus luteum formation. In aim 1, live-tissue confocal and two-photon microscopy will be used to analyze granulosa cell migration in intact follicles and determine how granulosa cell migration contributes to basal lamina invaginations and ovulation. In aim two, a novel mouse line that expresses a dominant-negative form of cofilin will be used to explore the hypothesis that cofilin dephosphorylation regulates granulosa cell migration. These studies will provide novel information about the regulation of ovulation and could lead to clinical treatments for anovulatory diseases.