Role of Membrane Estrogen Receptor 1 in Uterine Epithelial Response to Estrogen

项目摘要 17β-雌二醇（E2）在着床时控制子宫的生长和容受性， 在人类疾病如乳腺癌和子宫内膜癌以及子宫内膜异位症的发展和进展中。 主要的E2效应主要通过雌激素受体1（ESR 1）介导。大多数ESR 1是核的，但5-10% 位于细胞膜中。了解E2如何诱导其作用以及核和 膜ESR 1（分别为nESR 1和mESR 1）在正常生理学和病理学中是重要的调节因子。 类固醇内分泌学的目标。我们小组的莱文博士开发了两种独特而强大的小鼠模型， 仅有细胞核的ESR 1（NOER）小鼠，缺乏mESR 1但保留了nESR 1，以及仅有细胞膜的ESR 1 （MOER）小鼠，其表达mESR 1但缺乏nESR 1。重要的是，雌性NOER小鼠是不育的， 广泛的生殖异常，E2刺激子宫上皮细胞增殖受损， 动物这导致了一个意想不到的结论，即mESR 1和nESR 1必须协同工作，才能正常工作。 E2对子宫上皮细胞增殖等参数的调节，并提示E2的经典模型 雌激素作用集中于nESR 1是不完全正确的。我们的长期目标是使用NOER和MOER小鼠 确定mESR 1和nESR 1如何共同介导E2诱导的子宫上皮细胞有丝分裂和其他 E2效应本研究的目的是比较E2诱导的子宫上皮增殖， 卵巢切除的WT和NOER小鼠，以确定可能受损的nESR 1信号传导的具体方面 缺乏mESR 1。确定WT和NOER子宫E2反应的差异将使我们能够确定 mESR 1在促进nESR 1信号传导以允许E2诱导的上皮增殖中的关键作用。广泛 有证据表明mESR 1的作用是通过磷脂酰肌醇-3-激酶（PI 3 K）介导的， 丝裂原活化蛋白激酶（MAPK）通路，以及由这种信号传导诱导的下游事件可能是 对mESR 1的影响至关重要。这项工作还将确定MAPK和PI 3 K通路在细胞凋亡中的相对作用。 mESR 1作用。最后，我们开发了一种复合转基因小鼠，以确定截短的mESR 1 可以挽救NOER小鼠的生育能力和E2信号传导的其他缺陷。 我们的总体假设是，mESR 1通过蛋白激酶起作用，对细胞凋亡中的一个或多个步骤至关重要。 nESR 1信号级联反应由E2启动，并且用于开发MOER小鼠的截短mESR 1将是 能够恢复NOER小鼠的生育能力和E2反应性。拟议的实验将测试这一点 假设并提供有关nESR 1和mESR 1在促有丝分裂和 E2的其他影响。这些实验将为理解mESR 1在以下方面的作用提供机制基础： E2最重要的子宫效应之一，并描述mESR 1如何促进正常E2/nESR 1信号传导。 这些结果有可能成为偶像，并从字面上改变我们的模型类固醇激素的作用 是近半个世纪发展起来的，对女性生殖系统疾病也有临床意义。

Project Summary 17β-Estradiol (E2) controls uterine growth and receptivity at the time of implantation, and also plays major roles in development and progression of human diseases such as breast and endometrial cancer and endometriosis. Major E2 effects are primarily mediated through estrogen receptor 1 (ESR1). Most ESR1 is nuclear, but 5-10% is located in cell membranes. Understanding how E2 induces its actions and relative roles of nuclear and membrane ESR1 (nESR1 and mESR1, respectively) in both normal physiology and pathology is an important goal in steroid endocrinology. Dr. Levin from our group has developed two unique and powerful mouse models, the nuclear-only ESR1 (NOER) mouse, which lacks mESR1 but retains nESR1, and the membrane-only ESR1 (MOER) mouse, which expresses mESR1, but lacks nESR1. Critically, female NOER mice are infertile, with extensive reproductive abnormalities, and E2 stimulation of uterine epithelial proliferation is impaired in these animals. This led to the unexpected conclusion that mESR1 and nESR1 must work in concert to allow normal E2 regulation of uterine epithelial proliferation and other parameters, and suggests that the classical model of estrogen action focusing on nESR1 is not totally correct. Our long-term goal is to use NOER and MOER mice to define how mESR1 and nESR1 work together to mediate E2-induced uterine epithelial mitogenesis and other E2 effects. The objective of this research is to compare E2-induced uterine epithelial proliferation in ovariectomized WT and NOER mice to determine the specific aspects of nESR1 signaling that may be impaired by lack of mESR1. Identifying differences in E2 responses of WT and NOER uteri will allow us to determine the critical role(s) of mESR1 in facilitating nESR1 signaling to allow E2-induced epithelial proliferation. Extensive evidence suggests that mESR1 effects are mediated through the phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways, and downstream events induced by this signaling may be critical for mESR1 effects. This work will also determine the relative roles of the MAPK and PI3K pathways in mESR1 action. Finally, we have developed a compound transgenic mouse to determine if the truncated mESR1 used to develop the MOER mouse can rescue the fertility and other deficits in E2 signaling in the NOER mouse. Our overall hypothesis is that mESR1, acting through protein kinases, is critical for one or more steps in the nESR1 signaling cascade initiated by E2, and that the truncated mESR1 used to develop MOER mice will be capable of restoring fertility and E2 responsiveness in NOER mice. Proposed experiments will test this hypothesis and provide new and important information regarding nESR1 and mESR1's roles in mitogenic and other effects of E2. These experiments will provide a mechanistic basis for understanding the role of mESR1 in one of the most critical uterine effects of E2, and delineate how mESR1 facilitates normal E2/nESR1 signaling. These results have the potential to be iconoclastic and literally change our model of steroid hormone action developed over the past half century, and also have clinical significance for female reproductive pathologies.