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: 10263014
• 负责人: SUSAN WRAY
• 金额: $ 442.46万
• 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/10263014
• 关键词: Address; Animal Model; Astrocytes; Axon; Biochemical; Biological Assay; Biological Models; Brain; Calcium; Cell Differentiation process; Cells; Cues; Data; Destinations; Development; Doctor of Philosophy; Ectoderm; Electrophysiology (science); Embryo; Event; Functional disorder; GNRH1 gene; Gene Expression; Genes; Genetic; Genetic Screening; Genetic study; Goals; Gonadotropin Hormone Releasing Hormone; Homeodomain Proteins; Human Genetics; Idiopathic Hypogonadotropic Hypogonadism; Image; Immunofluorescence Immunologic; In Vitro; Islets of Langerhans; Knockout Mice; Label; Libraries; Link; Location; Measures; Modeling; Monitor; Morphology; Movement; Mus; Mutate; Mutation; Neural Crest; Neurodegenerative Disorders; Neuroendocrine Cell; Neuronal Differentiation; Neurons; Neurosecretory Systems; Nose; Outcome; Paper; Patients; Pattern; Peptide Synthesis; Peptides; Phenotype; Play; Population; Process; Property; Prosencephalon; Puberty; Publishing; Regulation; Reproduction; Role; Route; Signal Pathway; Synapses; Syndrome; System; Tracer; Transgenic Animals; Traumatic CNS injury; Vertebrates; Work; Zebrafish; cell fate specification; cell motility; craniofacial development; differential expression; graduate student; hypothalamic pituitary gonadal axis; islet; member; migration; molecular array; neurogenesis; novel strategies; pituitary gonadal axis; progenitor; programs; reproductive; reproductive function; screening; stem cells; tool

GnRH 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 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 neurons. Multiple approaches are used to identify and understand the multitude of molecules and factors which play a role in directing the GnRH 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 system in knockout mice, and perturbation of molecules in vitro and subsequent monitoring of GnRH neuronal movement. As GnRH neurons migrate they also mature and the two processes may in fact be linked. To investigate the maturation of GnRH neurons we use calcium imaging, electrophysiology and biochemical measures to examine GnRH neuronal activity and peptide secretion. In addition, we collaborate with labs performing human genetic screening of Kallman patients. Once a mutation is identified, we analyze the expression pattern in mice and perform biological assays to determine the outcome of the mutated gene on GnRH development. Over the past year, one article was published and one graduate student obtained their PhD with paper under revisions: Article) In vertebrates, Gonadotropin releasing hormone-1 (GnRH) neuroendocrine cells originate in the olfactory placode and migrate into the forebrain where they regulate reproduction. However, the embryonic lineage of their progenitors remains controversial. Most GnRH neurons are derived from placodal ectodermal progenitor cells, but data from lineage tracing in zebrafish (Whitlock et al., 2003) and mouse (Forni and Wray, 2012) indicate that some GnRH progenitor cells have a neural crest (NC) origin. In contrast, a recent study in zebrafish (Aguillon et al., 2018), using Islet-1/2 expression, identified this LIM-homeodomain protein in all developing GnRH neuroendocrine cells, and the authors concluded a homogenous origin from progenitors within the preplacodal ectoderm. Evidence in different animal models and systems suggests that expression of Islet-1 plays a pivotal role in cell fate specification and differentiation. Thus, expression of Islet-1/2 in all GnRH cells in the nasal placode may not be lineage dependent but rather initiated locally in the placode as part of the program for GnRH cell specification and/or differentiation. This study addresses this issue and shows two populations of olfactory derived GnRH neurons in embryonic mouse: Islet- 1/2(+) and Islet-1/2(-). Notably, triple-label immunofluorescence using the NC lineage tracer Wnt1, showed that GnRH neurons derived from Wnt1 progenitors are Islet-1/2(-). These results are consistent with two separate origins of GnRH neuroendocrine cells and suggest that either (1) NC-derived GnRH cells differentiate earlier than PE-derived GnRH cells or (2) different programs are used for cell specification in NC- vs. PE-derived GnRH cells. Thesis title) Neurorepair Promoting Crosstalk between Astrocytes and Olfactory ensheathing cells. This body of work addresses the signaling pathways that switch astrocytes from neurogenesis-inhibitory to neurogenesis-supportive to uncover novel approaches to reverse the progression of neurodegenerative diseases and traumatic CNS injuries.

GnRH神经元，生殖的关键，是从鼻基板和迁移到大脑，在那里他们成为下丘脑-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GnRH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）GnRH基因的表达，肽的合成和分泌在GnRH神经元。多种方法被用于识别和理解在将GnRH神经元引导到其在CNS中的最终位置中发挥作用的众多分子和因子。 这些包括从迁移与非迁移细胞中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GnRH系统的发育的形态学检查，以及体外分子的扰动和随后的GnRH神经元运动的监测。 随着GnRH神经元迁移，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GnRH神经元的成熟，我们使用钙显像，电生理和生化措施，检查GnRH神经元的活动和肽分泌。此外，我们还与实验室合作，对Kallman患者进行人类基因筛查。一旦发现突变，我们分析小鼠的表达模式，并进行生物测定，以确定突变基因对GnRH发育的影响。 在过去的一年里，发表了一篇文章，一名研究生获得了博士学位，论文正在修订中： Article）在脊椎动物中，促性腺激素释放激素-1（GnRH）神经内分泌细胞 起源于嗅板并迁移到前脑，在那里它们调节生殖。然而，它们的祖先的胚胎谱系仍然存在争议。大多数GnRH神经元来源于基板外胚层祖细胞，但来自斑马鱼谱系追踪的数据（Whitlock等人，2003）和小鼠（Forni和Wray，2012）表明一些GnRH祖细胞具有神经嵴（NC）起源。相反，最近在斑马鱼中的研究（Aguillon et al.，2018），使用Islet-1/2表达，在所有发育中的GnRH神经内分泌细胞中鉴定了这种LIM同源结构域蛋白，作者得出结论，该蛋白来自前基板外胚层内的祖细胞。不同动物模型和系统中的证据表明，Islet-1的表达在细胞命运特化和分化中起关键作用。因此，鼻基板中所有GnRH细胞中Islet-1/2的表达可能不是谱系依赖性的，而是作为GnRH细胞特化和/或分化程序的一部分在基板中局部启动。这项研究解决了这个问题，并显示了两个群体的嗅觉来源的GnRH神经元在胚胎小鼠：胰岛-1/2（+）和胰岛-1/2（-）。值得注意的是，使用NC谱系示踪剂Wnt 1的三重标记免疫荧光显示，来自Wnt 1祖细胞的GnRH神经元是Islet-1/2（-）。这些结果与GnRH神经内分泌细胞的两种不同来源一致，并表明（1）NC衍生的GnRH细胞比PE衍生的GnRH细胞更早分化或（2）NC与PE衍生的GnRH细胞中使用不同程序进行细胞特化。 神经修复促进星形胶质细胞和嗅鞘细胞之间的串扰。 这项工作的主体解决了信号通路，开关星形胶质细胞从神经发生抑制神经发生支持，以发现新的方法来逆转神经退行性疾病和创伤性CNS损伤的进展。