Development And Regulation Of The Gonadotropin Releasing Hormone System

促性腺激素释放激素系统的发育和调节

• 批准号: 8557010
• 负责人: SUSAN WRAY
• 金额: $ 220.82万
• 依托单位: NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8557010
• 关键词: Address; Adult; Afferent Neurons; Auditory; Axon; Binding Proteins; Biochemical; Brain; Calcium; Cartilage; Cells; Cephalic; Chloride Ion; Chlorides; Complex; Connective Tissue; Cranial Nerves; Cues; Cyclic GMP-Dependent Protein Kinases; Data; Destinations; Development; Dorsal; Electrophysiology (science); Embryo; Epidermis; FGFR1 gene; Family; Functional disorder; GABA Receptor; GTP-Binding Proteins; Ganglia; Gene Expression; Genetic; Glutamates; Goals; Gonadotropin Hormone Releasing Hormone; Growth Factor; Growth Factor Receptors; Head; Image; In Situ; In Vitro; Investigation; Knockout Mice; Labyrinth; Libraries; Ligands; Link; Location; Maps; Measures; Mediating; Membrane; Messenger RNA; Microscopy; Modeling; Monitor; Movement; Mus; Neural Crest; Neural Crest Cell; Neural tube; Neuronal Differentiation; Neurons; Neurosecretory Systems; Nose; Nuclear; Olfactory Epithelium; Organ; Organism; Pathway interactions; Patients; Peptide Synthesis; Peptides; Phenotype; Physiology; Platelet-Derived Growth Factor; Play; Population; Potassium; Process; Progesterone; Progesterone Receptors; Progestins; RU-486; Regulation; Relative (related person); Reproduction; Reproductive Behavior; Rodent; Role; Route; SERPINE1 gene; Schwann Cells; Screening procedure; Sensory; Signal Pathway; Signal Transduction Pathway; Source; Speed; Spinal Ganglia; Stem cells; Stromal Cell-Derived Factor 1; Synapses; Syndrome; System; Time; Tissues; Transgenic Animals; Vertebrates; Work; adiponectin; cell motility; cell type; cytokine; extracellular; gamma-Aminobutyric Acid; hypothalamic pituitary gonadal axis; improved; inhibitor/antagonist; interest; lens; melanocyte; member; migration; molecular array; negative elongation factor; neural plate; pituitary gonadal axis; prenatal; progenitor; receptor; reproductive; reproductive function; response; steroid hormone; tool

GnRH-1 (also known as LHRH) neurons, critical for reproduction, are derived from the nasal placode and migrate into the brain where they become integral members of the hypothalamic-pituitary-gonadal axis. We study mechanism(s) underlying GnRH-1 neuronal differentiation, migration and axonal targeting in normal/transgenic animals, and nasal explants. Using these same models, our work also addresses the mechanisms regulating (intrinsic and trans-synaptic) GnRH gene expression, peptide synthesis and secretion in GnRH-1 neurons. Multiple approaches are used to identify and understand the multitude of molecules and factors which play a role in directing the GnRH-1 neurons to their final location in the CNS. These include differential screening of libraries obtained from migrating versus non-migrating cells, examination of molecules differentially expressed at key locations along the migratory route, morphological examination of the development of the GnRH-1 system in knockout mice, and perturbation of molecules in vitro and subsequent monitoring of GnRH-1 neuronal movement. As GnRH-1 neurons migrate they also mature and the two processes may in fact be linked. To investigate the maturation of GnRH-1 neurons we use calcium imaging, electrophysiology and biochemical measures to examine GnRH-1 neuronal activity and peptide secretion. Over the past year two studies were finished: 1) Progesterone (P4), a steroid hormone, modulates reproductive behavior and is associated with rapid changes in GnRH secretion. However, a direct action of P4 on GnRH neurons has not been previously described. Receptors in the Progestin/adipoQ Receptor family (PAQRs), as well as Progesterone receptor membrane component 1 (PgRMC1) and its partner SERPINE1 mRNA binding protein 1 (SERBP1), have been shown to mediate rapid progestin actions in various tissues, including the brain. This study shows that PgRMC1 and SERBP1, but not PAQRs, are expressed in prenatal GnRH neurons. Expression of PgRMC1 and SERBP1 was verified in adult mouse GnRH neurons. To investigate the effect of P4 on GnRH neuronal activity, calcium imaging was used on primary GnRH neurons maintained in explants. Application of P4 significantly decreased the activity of GnRH neurons, independent of GABAergic and glutamatergic input, suggesting a direct action of P4 on GnRH neurons. Inhibition was not blocked by RU486, an antagonist of the classic nuclear P4 receptor. Inhibition was also maintained after uncoupling of the inhibitory regulative G-protein (Gi/o), the signal transduction pathway used by PAQRs. However, AG-205, a PgRMC1 ligand and inhibitor, blocked the rapid P4-mediated inhibtion, and inhibition of protein kinase G, thought to be activated downstream of PgRMC1, also blocked the inhibitory activity of P4. These data show for the first time that P4 can act directly on GnRH neurons through PgRMC1 to inhibit neuronal activity. 2) Sensory neurons in vertebrates are derived from two embryonic transient cell sources: neural crest and ectodermal placodes. The placodes are thickenings of ectodermal tissue that are responsible for the formation of cranial ganglia as well as complex sensory organs that include the lens, inner ear, and olfactory epithelium . The neural crest cells have been indicated to arise at the edges of the neural plate/dorsal neural tube, from both the neural plate and the epidermis in response to reciprocal interactions. neural crest cells migrate throughout the organism, and give rise to a multitude of cell types that include melanocytes, cartilage and connective tissue of the head, components of the cranial nerves, the dorsal root ganglia, and Schwann cells. The embryonic definition of these two transient populations and their relative contribution to the formation of sensory organs has been investigated and debated for several decades. Historically, all placodes have been described as exclusively derived from non-neural ectodermal progenitors. Recent genetic fate-mapping studies suggested a neural crest contribution to the olfactory placodes as well as the otic (auditory) placodes in rodents. This review analyzes and discusses some recent developmental studies on the olfactory placode, placodal derivatives, and olfactory system. New investigations using Cre-lox-mice to specifically remove molecules of interest from GnRH-1 cells during development will be continued this year with specific studies on the early development of the GnRH-1 neurons and the location of their progenitor cells in relation to nasal placodal cells and neural crest. A study on the interaction of cytokines and GABA during GnRH neuronal migration is being completed. Here we find that Stromal derived growth factor (SDF-1) and Gamma-aminobutyric acid (GABA) are two extracellular cues that regulate the rate of neuronal migration during development and may, in fact, act synergistically. GABA and SDF-1 are shown to exert opposite effects on the speed of cell movement by activating depolarizing or hyperpolarizing signaling pathways, GABA via changes in chloride and SDF-1 via changes in potassium. GABA and SDF-1 were also found to act synergistically to promote linear rather than random movement. The simultaneous activation of these signaling pathways therefore results in tight control of cellular speed and improved directionality along the migratory pathway of GnRH neurons. Other studies in progress are examining the role of growth factor receptors (FGFR1, PDGF), and NELF (a migrational molecule), in GnRH-1 development as well as in situ characterization of the migration of GnRH-1 neurons (real time microscopy). In addition, we continue to study the physiology of GnRH neurons. Currently we are evaluating the mechanism for GABA remaining excitatory to GnRH by evaluating chloride transporters and GABA receptor subtypes and their distribution in GnRH neurons. Other studies include examining/identifying 1) molecules that modulate GnRH-1 neuronal activity that participate in reproductive functions such as adiponectin, 2) midline cues which influence olfactory axon outgrowth and 3) the dynamics of GnRH-1 neuronal migration.

GnRH-1（也称为 LHRH）神经元对生殖至关重要，源自鼻基板并迁移到大脑中，成为下丘脑-垂体-性腺轴的组成部分。我们研究正常/转基因动物和鼻外植体中 GnRH-1 神经元分化、迁移和轴突靶向的潜在机制。使用这些相同的模型，我们的工作还解决了 GnRH-1 神经元中（内在和跨突触）GnRH 基因表达、肽合成和分泌的调节机制。使用多种方法来识别和理解在引导 GnRH-1 神经元到达中枢神经系统最终位置方面发挥作用的多种分子和因子。 这些包括对从迁移细胞和非迁移细胞获得的文库进行差异筛选，检查迁移路线上关键位置差异表达的分子，对基因敲除小鼠中 GnRH-1 系统发育的形态学检查，以及体外分子扰动和随后监测 GnRH-1 神经元运动。 当 GnRH-1 神经元迁移时，它们也会成熟，这两个过程实际上可能是相关的。 为了研究 GnRH-1 神经元的成熟，我们使用钙成像、电生理学和生化措施来检查 GnRH-1 神经元活性和肽分泌。 过去一年完成了两项研究： 1) 黄体酮 (P4) 是一种类固醇激素，可调节生殖行为并与 GnRH 分泌的快速变化相关。然而，P4 对 GnRH 神经元的直接作用尚未被描述。孕激素/adipoQ 受体家族 (PAQR) 中的受体以及孕酮受体膜成分 1 (PgRMC1) 及其伴侣 SERPINE1 mRNA 结合蛋白 1 (SERBP1) 已被证明可以介导包括大脑在内的各种组织中孕激素的快速作用。这项研究表明 PgRMC1 和 SERBP1 在产前 GnRH 神经元中表达，但 PAQR 不表达。 PgRMC1 和 SERBP1 的表达在成年小鼠 GnRH 神经元中得到验证。为了研究 P4 对 GnRH 神经元活性的影响，对外植体中维持的原代 GnRH 神经元进行钙成像。 P4 的应用显着降低了 GnRH 神经元的活性，与 GABA 能和谷氨酸能输入无关，表明 P4 对 GnRH 神经元有直接作用。 RU486（经典核 P4 受体的拮抗剂）不会阻断抑制作用。抑制性调节 G 蛋白 (Gi/o)（PAQR 使用的信号转导途径）解偶联后，抑制作用也得以维持。然而，PgRMC1 配体和抑制剂 AG-205 阻断了 P4 介导的快速抑制，并且被认为在 PgRMC1 下游激活的蛋白激酶 G 的抑制也阻断了 P4 的抑制活性。这些数据首次表明P4可以通过PgRMC1直接作用于GnRH神经元，抑制神经元活动。 2）脊椎动物的感觉神经元来源于两种胚胎瞬时细胞来源：神经嵴和外胚层基板。基板是外胚层组织的增厚部分，负责形成颅神经节以及包括晶状体、内耳和嗅觉上皮在内的复杂感觉器官。已表明，神经嵴细胞出现在神经板/背侧神经管的边缘，来自神经板和表皮，以响应相互的相互作用。神经嵴细胞在整个生物体中迁移，并产生多种细胞类型，包括黑色素细胞、头部软骨和结缔组织、颅神经成分、背根神经节和雪旺细胞。这两个瞬时群体的胚胎定义及其对感觉器官形成的相对贡献已经被研究和争论了几十年。从历史上看，所有基板都被描述为完全源自非神经外胚层祖细胞。最近的遗传命运图谱研究表明，神经嵴对啮齿动物的嗅觉基板和耳（听觉）基板有贡献。本文分析和讨论了嗅觉基板、基板衍生物和嗅觉系统的一些最新发展研究。 今年将继续使用 Cre-lox-小鼠在发育过程中从 GnRH-1 细胞中特异性去除感兴趣分子的新研究，具体研究 GnRH-1 神经元的早期发育及其祖细胞相对于鼻基板细胞和神经嵴的位置。一项关于 GnRH 神经元迁移过程中细胞因子和 GABA 相互作用的研究正在完成。在这里，我们发现基质衍生生长因子（SDF-1）和γ-氨基丁酸（GABA）是调节发育过程中神经元迁移速率的两种细胞外信号，实际上可能协同作用。 GABA 和 SDF-1 通过激活去极化或超极化信号通路对细胞运动速度产生相反的影响，GABA 通过改变氯离子而 SDF-1 通过改变钾离子。研究还发现 GABA 和 SDF-1 可以协同作用，促进线性运动而不是随机运动。因此，这些信号通路的同时激活会导致细胞速度的严格控制，并改善 GnRH 神经元迁移通路的方向性。其他正在进行的研究正在检查生长因子受体（FGFR1、PDGF）和 NELF（一种迁移分子）在 GnRH-1 发育中的作用以及 GnRH-1 神经元迁移的原位表征（实时显微镜）。此外，我们继续研究GnRH神经元的生理学。目前，我们正在通过评估氯转运蛋白和 GABA 受体亚型及其在 GnRH 神经元中的分布来评估 GABA 对 GnRH 保持兴奋的机制。 其他研究包括检查/鉴定 1) 调节参与生殖功能的 GnRH-1 神经元活动的分子，如脂联素；2) 影响嗅觉轴突生长的中线线索；以及 3) GnRH-1 神经元迁移的动态。