The Luteinizing Hormone Releasing Hormone System

黄体生成素释放激素系统

• 批准号: 7143863
• 负责人: SUSAN WRAY
• 金额: --
• 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/7143863
• 关键词: axon; biological signal transduction; cell differentiation; cell migration; estrogens; gamma aminobutyrate; gene expression; genetically modified animals; gonadotropin releasing factor; hormone receptor; hormone regulation /control mechanism; laboratory mouse; luteinizing hormone; neuroendocrine system; olfactory nerve

LHRH (also known as GnRH-1) 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 LHRH 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) LHRH gene expression, peptide synthesis and secretion in LHRH neurons. Multiple approaches are used to identify and understand the multitude of molecules and factors which play a role in directing the LHRH 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 LHRH system in knockout mice, and perturbation of molecules in vitro and subsequent monitoring of LHRH neuronal movement. As LHRH neurons migrate they also mature and the two processes may in fact be linked. To investigate the maturation of LHRH neurons we use calcium imaging, electrophysiology and biochemical measures to examine LHRH neuronal activity and peptide secretion. Continuing on work from the past years, further investigations into the role of GABA in LHRH neuronal migration was examined by mapping the development of LHRH cells in GAD67 knockout mice using immunocytochemistry. As in many of the animal models examined to date, the LHRH system although altered, is able to compensate for the loss of GABA. In addition we are continuing to characterize, using molecular and morphological approaches, LHRH expression in the developing incisor and are determining the lineage relation between these LHRH cells and neuroendocrine LHRH cells derived from the nasal placode as well as common transcription factors that might be important for initiating LHRH gene expression. Studies in progress center on the role of NELF (a ?migrational? molecule), cytokines, and growth factors in LHRH development as well as in situ characterization of the migration of LHRH neurons (real time microscopy). In addition, we continue to study the role of estrogen on LHRH neuronal activity and have recently finished a differential screen (constructed from single LHRH cells) between LHRH neurons ? estrodiol treatment. Currently, the genes identified are being examined at the cellular level (using either immunocytochemistry and/or in situ hybridization histochemistry). These studies will identify the best candidate genes to continue to characterize. Studies in progress examine the electrical properties associated with LHRH neuronal activity (combining electrical recording and calcium imaging). Future studies are designed to expand upon our present results and are directed at the molecules and cues important for development of the olfactory and LHRH neuronal systems as well as the mechanisms regulating LHRH neuronal activity. Specific studies in progress focus on: 1) isolation of midline cues which influence olfactory axon outgrowth; 2) the role of NELF and other molecules in LHRH migration, 3) identifying pacemaker molecules in LHRH neurons that participate in establishment/maintenance of rhythmic activity, 4) genes differentially expressed in LHRH neurons as a function of GABAergic signals and 5) the mechanisms by which estrogen alters LHRH neuronal activity.

LHRH（也称为GnRH-1）神经元，对生殖至关重要，来源于鼻基板并迁移到大脑中，在那里它们成为下丘脑-垂体-性腺轴的组成部分。我们在正常/转基因动物和鼻外植体中研究LHRH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，我们的工作也解决了机制调节（内在的和跨突触）LHRH基因的表达，肽的合成和分泌LHRH神经元。使用多种方法来识别和理解在将LHRH神经元引导到其在CNS中的最终位置中起作用的众多分子和因子。这些包括从迁移细胞和非迁移细胞获得的文库的差异筛选，在迁移路线的关键位置沿着差异表达的分子的检查，在敲除小鼠中LHRH系统的发育的形态学检查，以及体外分子的扰动和随后的LHRH神经元运动的监测。随着LHRH神经元的迁移，它们也成熟，这两个过程实际上可能是联系在一起的。为了研究LHRH神经元的成熟，我们使用钙成像，电生理和生化方法来检测LHRH神经元的活性和肽分泌。 继续从过去几年的工作，GABA在LHRH神经元迁移的作用进行了进一步的调查，通过使用免疫细胞化学绘制GAD 67基因敲除小鼠的LHRH细胞的发展。与迄今为止检查的许多动物模型一样，LHRH系统尽管发生了改变，但能够补偿GABA的损失。此外，我们正在继续表征，使用分子和形态学的方法，LHRH表达在发展中的切牙，并确定这些LHRH细胞和神经内分泌LHRH细胞来自鼻基板以及共同的转录因子，可能是重要的启动LHRH基因表达之间的谱系关系。正在进行的研究集中在NELF的作用（a？移民？分子）、细胞因子和生长因子在LHRH发育中的作用以及LHRH神经元迁移的原位表征（真实的时间显微镜）。此外，我们继续研究雌激素对LHRH神经元活性的作用，并在最近完成了LHRH神经元之间的差异筛选（从单个LHRH细胞构建）。雌二醇治疗。目前，已确定的基因正在细胞水平上进行检查（使用免疫细胞化学和/或原位杂交组织化学）。这些研究将确定最佳的候选基因继续表征。正在进行的研究检查与LHRH神经元活动相关的电特性（结合电记录和钙成像）。未来的研究旨在扩大我们目前的研究结果，并针对嗅觉和LHRH神经元系统的发展以及调节LHRH神经元活性的机制的重要分子和线索。具体的研究进展主要集中在：1）影响嗅轴突生长的中线线索的分离; 2）NELF和其他分子在LHRH迁移中的作用，3）鉴定LHRH神经元中参与节律活动的建立/维持的起搏分子，4）在LHRH神经元中作为GABA能信号的函数差异表达的基因，和5）雌激素改变LHRH神经元活性的机制。