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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要促性腺激素释放激素（GnRH）神经元形成调节生育能力的最终共同中央通路。正确模式的 GnRH 释放是生育能力所必需的，但在患有多囊卵巢的女性中经常会受到干扰综合征（多囊卵巢综合症）。高雄激素性 PCOS 影响约 8-10% 的女性。这些女人身上都有一种执着黄体生成素 (LH) 以及可能的 GnRH 的高频率释放。产前雄激素化 (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，并且可以用于研究这种增加的机制。与 PCOS 相似的病理生理学在年轻时被发现年龄，表明这种疾病的前因可能是在发育过程中被编程的。在之前的作品中通过不同的资助机制 (NCTRI)，我们描述了 GnRH 神经元活动的发展，并 GABA 传输到这些细胞，表明 PNA 在青春期前破坏了这两个参数，并且 PNA- 青春期前后引起的变化是不同的。这些背后的神经生物学机制观察结果在很大程度上是未知的。我们解释这些发现的工作模型是 1) PNA 改变了 GnRH 神经元及其传入神经元的生物物理特性； 2）至少部分改变表观遗传编程这些变化是这些变化的基础； 3) PNA 增加青春期前对 GnRH 神经元的兴奋性 GABA 突触驱动并且这种增加在成年人中仍在继续； 4) PNA小鼠青春期前，GnRH神经元启动内在变化适应GABA驱动力增加，射击输出减少； 5) PNA小鼠的发育变化导致这些 GnRH 神经元适应失败，因此在 PNA 成人中，增加的 GABA 驱动有助于 GnRH 神经元放电增加； 6) 神经内分泌驱动力的增强会增加雄激素，这一点至关重要维持成人神经内分泌 PNA 表型。我们将在两个目标上测试这个模型。目标 1 将确定 PNA 小鼠青春期前 GnRH 神经元适应 GABA 驱动增加的机制。目标 2 将描述 GnRH 神经元在发育过程中的表观遗传景观，以及诱导的变化由 PNA 提供。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受到评估。初步数据表明 GnRH 神经元动作电位放电、钙电流和与对照组相比，青春期前和成年 PNA 小鼠的钾电流调节均存在差异。到为了补充电生理学研究，我们已将表观遗传分析应用于由一些数百个神经元并建立了荧光细胞分选方案，产生足够数量的富集用于这些分析的 GnRH 神经元。因此，我们有能力检查分子和生物物理 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对 GnRH 神经元通过青春期过程、相关的表观遗传变化以及这些参数如何在雄激素过多症；不可能从人类研究中获得这些见解。