Development of the GnRH neuronal network and effects of prenatal androgen exposure

GnRH 神经网络的发育和产前雄激素暴露的影响

• 批准号: 10226409
• 负责人: Suzanne M MOENTER
• 金额: $ 43.38万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10226409
• 关键词: Action Potentials; Adult; Affect; Age; Androgenization; Androgens; Animal Model; Anterior Pituitary Hormones; Automobile Driving; Biophysics; Brain; Calcium; Cell Separation; Cell physiology; Cells; Complement; Comprehension; DNA Methylation; Data; Development; Disease; Drops; Electrophysiology (science); Epigenetic Process; Exhibits; Exposure to; Failure; Feedback; Female; Female infertility; Fertility; Follicle Stimulating Hormone; Frequencies; Functional disorder; Funding Mechanisms; Future; Goals; Gonadotropin Hormone Releasing Hormone; Gonadotropins; Homeostasis; Human; Infertility; Knowledge; Lead; Libraries; Luteinizing Hormone; Messenger RNA; Methods; Modeling; Molecular; Mus; Nature; Neurobiology; Neurons; Neurosecretory Systems; Output; Ovarian; Ovariectomy; Ovary; Pathology; Pathway interactions; Pattern; Phenotype; Physiologic pulse; Physiological; Polycystic Ovary Syndrome; Positioning Attribute; Potassium; Pregnancy; Prevention; Process; Property; Protocols documentation; Puberty; Regulation; Reproduction; Research; Role; Steroids; Symptoms; Synapses; Systems Development; Testing; Variant; Woman; Work; biophysical properties; epigenetic profiling; gamma-Aminobutyric Acid; genome-wide; histone methylation; insight; neurobiological mechanism; neurodevelopment; neuroendocrine phenotype; neurotransmission; novel therapeutic intervention; prenatal; prenatal exposure; prepuberty; programs; relating to nervous system; reproductive; reproductive function; response; transmission process; treatment strategy; voltage

Project Summary Gonadotropin-releasing hormone (GnRH) neurons form the final common central pathway regulating fertility. Properly patterned GnRH release is required for fertility and is often disrupted in women with polycystic ovary syndrome (PCOS). Hyperandrogenic PCOS affects ~8-10% of women. In these women, there is a persistent high frequency of luteinizing hormone (LH), and likely GnRH, release. Prenatally androgenized (PNA) mice have neuroendocrine phenotypes similar to women with PCOS, including high LH pulse frequency, and can be used to study mechanisms of this increase. Pathophysiology similar to PCOS is being detected at younger ages, suggesting the antecedents of this disorder may be developmentally programmed. In the previous work from a different funding mechanism (NCTRI), we characterized the development of GnRH neuron activity and GABA transmission to these cells, showing that PNA disrupts both parameters before puberty, and that PNA- induced changes before and after puberty are different. The neurobiological mechanisms underlying these observations are largely unknown. Our working model to explain these findings is that 1) PNA alters the biophysical properties of GnRH neurons and their afferents; 2) altered epigenetic programing at least in part underlies these changes; 3) PNA increases excitatory GABA synaptic drive to GnRH neurons before puberty and this increase continues in adults; 4) before puberty in PNA mice, GnRH neurons initiate intrinsic changes to adapt to the increased GABA drive, and firing output is reduced; 5) developmental changes in PNA mice lead to failure of these GnRH neuron adaptations, so that in PNA adults, increased GABA drive contributes to increased GnRH neuron firing; 6) the increased neuroendocrine drive increases androgens, which are critical to maintain neuroendocrine PNA phenotypes in adults. We will test this model in two aims. Aim 1 will identify the mechanisms underlying prepubertal adaptation of GnRH neurons in PNA mice to increased GABA drive. Aim 2 will characterize the epigenetic landscape in GnRH neurons during development, and changes induced by PNA. The role of the ovary and androgen replacement in establishing and maintaining epigenetic changes will also be assessed. Preliminary data indicate that GnRH neuron action potential firing, calcium currents and potassium currents are all differentially regulated in prepubertal vs adult PNA mice compared to controls. To complement the electrophysiology studies, we have adapted epigenetic profiling to libraries made from a few hundred neurons and established fluorescent cell sorting protocols that yield sufficient numbers of enriched GnRH neurons for these analyses. We are thus positioned to examine the molecular and biophysical underpinnings of the functional changes of GnRH neurons observed in PNA mice. This work will provide mechanistic insight currently lacking on the typical functional development of GnRH neurons through the pubertal process, associated epigenetic changes, and how these parameters may be altered in hyperandrogenic disorders; is not possible to obtain these insights from human studies.

项目摘要 促性腺激素释放激素（GNRH）神经元构成调节生育能力的最终公共中心途径。 生育需要正确的图案GNRH释放，并且在多囊卵巢的女性中经常被破坏 综合征（PCOS）。高雄激素PCOS影响约8-10％的女性。在这些女人中，有一个持久的 黄叶激素（LH）和可能的GnRH的高频释放。产前雄激素（PNA）小鼠 具有与PCOS女性相似的神经内分泌表型，包括高LH脉冲频率，可以是 用于研究这种增加的机制。在年轻人处检测到类似于PCOS的病理生理学 年龄，表明这种疾病的先例可能是在发育中编程的。在以前的工作中 从不同的资金机制（NCTRI）中，我们表征了GnRH神经元活性和 GABA向这些细胞传播，表明PNA在青春期前破坏了两个参数，并且PNA- 青春期前后的诱导变化不同。这些神经生物学机制 观察结果在很大程度上未知。我们解释这些发现的工作模型是1）PNA改变 GnRH神经元及其传入的生物物理特性； 2）至少部分改变表观遗传编程 这些变化是基础的； 3）PNA在青春期之前将兴奋性GABA突触驱动器增加到GnRH神经元 成年人的增长仍在继续。 4）在PNA小鼠青春期之前，GNRH神经元启动内在变化 适应增加的GABA驱动器，并减少发射输出； 5）PNA小鼠的发育变化 导致这些GNRH神经元适应的失败，因此在PNA成年人中，GABA驱动器增加有助于 GNRH神经元射击增加； 6）神经内分泌驱动的增加增加了雄激素，这是至关重要的 维持成人的神经内分泌PNA表型。我们将以两个目标测试该模型。 AIM 1将确定 PNA小鼠中GnRH神经元的前碱适应的机制可增加GABA驱动。 AIM 2将在开发过程中表征GNRH神经元中的表观遗传景观，并引起变化 由PNA。卵巢和雄激素替代在建立和维持表观遗传变化中的作用 也将评估。初步数据表明GNRH神经元动作电势发射，钙电流和 与对照组相比，在青春期前与成年PNA小鼠中，钾电流均受到差异调节。到 补充电生理研究，我们对表观遗传学分析进行了调整到由少数图书馆 数百个神经元和建立的荧光细胞分选方案，产生足够数量的富集 这些分析的GnRH神经元。因此，我们可以检查分子和生物物理 在PNA小鼠中观察到的GnRH神经元功能变化的基础。这项工作将提供 目前缺乏通过典型的GNRH神经元功能发展的机械洞察力 青春期过程，相关的表观遗传变化以及如何改变这些参数 高雌激素疾病；无法从人类研究中获得这些见解。