Exploring the Role of the Prokineticin System in Human Reproduction

描述(申请人提供)：下丘脑内的一种独特的神经网络启动并维持人类的生殖功能。它通过协调神经网络中单一神经内分泌十肽--促性腺激素释放激素(GnRH)的合成和脉动性分泌来完成这一任务。在过去的二十年里，通过对GnRH缺乏的人类的研究，已经发现了几个控制GnRH个体发育的基因和途径。一些G蛋白偶联受体(GPCRs)及其同源配体参与了人类生殖的神经内分泌调控。然而，对其中许多新基因和途径的了解仍处于早期阶段，需要进一步研究。我的研究项目的总体目标是探索原激动素系统在控制人类生殖发育和功能的神经网络中的作用。原激动素信号系统，原激动素2(PROK2)和PROK2受体(PROKR2)，最近作为神经内分泌控制生殖的关键调节因子出现在小鼠和人类身上。PROK2和PROKR2在中枢神经系统中高表达，在嗅球神经发生和随后的GnRH神经元迁移中发挥重要作用。原激动素2也是视交叉上核的关键昼夜节律输出分子，调节动物的摄食行为。尽管人类和小鼠的研究都已经证实并坚定地确立了原激动素途径在哺乳动物繁殖中的关键作用，但这种生物学的一些特征仍然令人困惑，这表明人类存在更复杂的系统生物学途径。本研究的目的是阐明GnRH缺乏症的遗传结构，并探讨PROKR2突变影响受体功能的分子机制。我的第一个目标是确定PROKR2杂合突变在孤立性低促性腺激素减退症(IHH)中的作用，测试假设，在GnRH缺乏的患者中，PROKR2杂合突变不足以导致孤立的低促性腺激素减退表型，但可以与第二个基因“命中”相关的表型贡献。我的第二个目标是阐明保守氨基酸的突变干扰PROKR2功能的机制，以识别这些氨基酸的功能和该受体的结构域，并识别与细胞内转运(伴侣蛋白)和 GPCRs的降解途径。总之，这些研究将促进我们对促性腺激素释放激素缺乏的病因和原激动素系统在这一过程中的作用的理解，并将为深入了解PROKR2的结构-活性关系提供深入的见解，并可能对GPCR2生物学产生潜在的影响。这项工作将扩展我的研究培训，既包括了解疾病致病机制的分子方法，也包括将我的发现与生殖发育和功能障碍患者的表型联系起来的翻译方法。

DESCRIPTION (provided by applicant): A unique neural network within the hypothalamus initiates and maintains reproductive function in humans. It accomplishes this task by coordinating the synthesis and pulsatile secretion of a single neuroendocrine decapeptide, gonadotropin-releasing hormone (GnRH), from this neural network. In the last two decades, several genes and pathways that govern GnRH ontogeny have been discovered by studying humans with GnRH deficiency. Several G protein-coupled receptors (GPCRs) and their cognate ligands have been implicated in the neuroendocrine control of human reproduction. However, the knowledge about many of these new genes and pathways are still in the early stages and require further investigation. The overall goal of my research project is to explore the role of th prokineticin system in the neural network that controls human reproductive development and function. The prokineticin signaling system, prokineticin 2 (PROK2) and PROK2 receptor (PROKR2), has recently emerged as a critical regulator of the neuroendocrine control of reproduction in both mice and humans. PROK2 and PROKR2 are highly expressed in the central nervous system and play an important role in olfactory bulb neurogenesis and subsequently in GnRH neuronal migration. Prokineticin 2 also acts as a key circadian output molecule from the suprachiasmatic nucleus and regulates ingestive behavior in animals. Although both human and mouse studies have confirmed and firmly established a key role of the prokineticin pathway in mammalian reproduction, several features of this biology remain puzzling, suggesting a more complex systems biology of this pathway in humans. The objective of this proposal is to clarify the genetic architecture of GnRH deficiency and to investigate the molecular mechanisms through which PROKR2 mutations affect receptor function. My first aim is to define the role of the PROKR2 heterozygous mutations in isolated hypogonadotropic hypogonadism (IHH), testing the hypothesis that heterozygous mutations in PROKR2 in patients with GnRH deficiency are not sufficient to cause the hypogonadotropic hypogonadism phenotype in isolation, but can contribute to the phenotype in association with a second genetic "hit". My second aim is to elucidate mechanisms by which mutations in conserved amino acids interfere with PROKR2 function to recognize the functions of these amino acids and domains of this receptor and also to identify proteins connected to intracellular trafficking (chaperones) and degradation pathways of GPCRs. Together, these studies will advance our understanding of the etiology of GnRH deficiency and the role of prokineticin system in this process, and will provide insights into the structure-activity relationships of the PROKR2, with potential implications for GPCR biology in general. This work will expand my research training to encompass both a molecular approach to understanding the mechanisms that cause disease and a translational approach in relating my findings to the phenotypes of patients with disorders of reproductive development and function.