ERa Signaling Mechanisms Regulating Ovarian Function

调节卵巢功能的 ERa 信号机制

• 批准号: 7763056
• 负责人: Jon E Levine
• 金额: $ 40.5万
• 依托单位: NORTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7763056
• 关键词: Anabolism; Androgens; Animals; Back; Brain; Cells; Coupled; DNA; Endocrine System Diseases; Enzymes; Estradiol; Estrogen Receptor alpha; Estrogens; Excision; Feedback; Female; Fertility; Gene Expression; Genes; Genotype; Gonadotropin Hormone Releasing Hormone; Gonadotropins; Hormonal; Hyperandrogenism; Hypothalamic structure; In Situ Hybridization; In Vitro; Knock-in Mouse; Mediating; Mediation; Membrane; Microdialysis; Molecular; Monitor; Mus; Mutant Strains Mice; Mutate; Neuroglia; Neurons; Neurosecretion; Neurosecretory Systems; Ovarian; Ovarian Follicle; Ovary; Partner in relationship; Pathogenesis; Pathway interactions; Phenotype; Physiological; Pituitary Gland; Polycystic Ovary Syndrome; Production; Regulation; Research Design; Role; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Steroid biosynthesis; Steroids; Structure of nucleus infundibularis hypothalami; System; feeding; hypothalamic pituitary ovarian axis; immunocytochemistry; in vivo; insight; intraovarian; kisspeptin; knockout gene; mouse model; mutant; novel; receptor binding; receptor coupling; reproductive; reproductive axis; research study; response; theca cell; transcription factor

Ovarian estrogens exert critically important homeostatic feedback actions in the brain, pituitary, and ovary to restrain androgen biosynthesis. Disruption of these feedback controls invariably leads to dysregulation of gonadotropin secretions, androgen excess, and impaired fertility. Estrogen receptor alpha (ERa) appears to mediate most of these major negative feedback actions. ERa signaling mechanisms include "classical genotropic" effects mediated by direct binding of receptors to DNA, "non-classical genotropic" effects involving tethering of ERs to other transcription factors, and "non-classical non-genotropic" actions mediated by ERs coupled to membrane-initiated signaling pathways. The proposed studies use novel ERa mutant mice to further determine cellular mechanisms by which ERa mediates E2 feedback effects. We have utilized mutant ERa knock-in mice, which confer non-classical genotropic and non-genotropic signaling in the absence of classical signaling, to determine that non-classical ERa signaling conveys E2 negative feedback actions on LH secretion. Aim 1 determines if these feedback actions are manifest in brain by directly monitoring GnRH secretory responses to E2 treatments in WT (ERa+/+), ERa gene knockout (ER-/-), and non-classical ERa gene "knock-in" (ER-/AA) mice, as well as in neuron-specific ERa-/- mice. Aim 2 examines the involvement of non-classical genotropic vs. non-genotropic ERa signaling in negative feedback; the ability of E2 to exert actions in afferent circuitries controlling GnRH release will be compared among the three genotypes. Aim 3 analyzes the locus of intraovarian feed-back in theca cell-specific ERa null mutant mice. We then assess involvement of classical vs. non-classical ERa signaling in regulating androgen synthesis by analyzing E2 effects in cultured ovarian follicles of ERa+/+, ERa/-., ERa-/AA mice. In Aim 4, we determine the extent to which E2 actions are mediated by non-classical genotropic vs. membrane-initiated ERa signaling. New animals will be generated that express ERs conferring non-classical membrane-initiated signaling only, or non-classical genotropic signaling only. The extent to which E2 actions in the reproductive axis are rescued in these mice will be determined. These experiments will clarify the basic mechanisms by which ERa signaling regulates cellular and physiological function, and may provide important insights into the pathogenesis of hyperandrogenism in endocrine disorders such as polycystic ovary syndrome (PCOS).

卵巢雌激素在脑、垂体和卵巢中发挥至关重要的稳态反馈作用， 抑制雄激素生物合成。这些反馈控制的破坏总是导致调节失调， 促性腺激素分泌、雄激素过多和生育能力受损。雌激素受体α（ER α）似乎 介导了这些主要的负反馈行为。ER α信号传导机制包括“经典的遗传性” 由受体与DNA直接结合介导的效应，“非经典遗传性”效应，包括 ER与其他转录因子的束缚，以及ER介导的“非经典非基因向性”作用 与膜启动的信号传导途径相连。拟议的研究使用新的ER α突变小鼠， 进一步确定ER α介导E2反馈效应的细胞机制。我们利用变种人 ERa基因敲入小鼠，其在缺乏ERa的情况下赋予非经典的遗传性和非遗传性信号传导。 经典信号传导，以确定非经典ERa信号传导传递E2负反馈作用。 LH分泌。目的1通过直接监测GnRH来确定这些反馈行为是否在大脑中表现出来 WT（ER a +/+）、ER a基因敲除（ER-/-）和非经典ER a中对E2处理的分泌反应 基因“敲入”（ER-/AA）小鼠以及神经元特异性ER α-/-小鼠中的细胞毒性。目标2审查参与情况 负反馈中的非经典遗传性与非遗传性ER α信号传导; E2发挥作用的能力 将在三种基因型之间比较控制GnRH释放的传入回路中的作用。目标3 分析卵泡膜细胞特异性ER α无效突变小鼠中卵巢内反馈的位点。然后我们评估 通过分析E2，经典与非经典ER α信号传导在调节雄激素合成中的参与 ER α +/+，ER α/-，ER α-/AA小鼠。在目标4中，我们确定 E2的作用是由非经典的遗传性与膜启动的ER α信号传导介导的。新 将产生表达仅赋予非经典膜起始信号传导的ER的动物，或 仅非经典的遗传信号传导。E2在生殖轴中的作用被拯救的程度 在这些小鼠中，将被确定。这些实验将阐明ER α 信号调节细胞和生理功能，并可能提供重要的见解， 多囊卵巢综合征（PCOS）等内分泌疾病中高雄激素血症的发病机制。