The role of Kisspeptin/Neurokinin B/Dynorphin (KNDy) neurons in the pathogenesis of polycystic ovarian syndrome

项目简介：多囊卵巢综合征(PCOS)是世界范围内导致不孕的主要原因。这个 该综合征的主要特征是无排卵和囊性卵巢，月经周期紊乱和 高雄激素血症。卵巢由驻留在下丘脑的一小群神经元控制， 促性腺激素释放激素(GnRH)神经元。这些神经元的活动调节搏动性黄体生成。 脑下垂体释放激素，控制排卵和性类固醇激素的产生。 卵巢。类固醇激素反过来通过传入神经网络作用于大脑，为大脑提供关键的 反馈给促性腺激素释放激素神经元。在许多患有多囊卵巢综合征的女性中，这一反馈途径受到损害，导致 促性腺激素释放激素/促黄体生成素脉冲频率驱动综合征的下游后果。神经元上游 来自共表达Kispeptin、神经激肽B和强啡肽的GnRH神经元(KNDy神经元) 与类固醇激素反馈和促性腺激素释放激素/促黄体生成素脉冲生成密切相关，因此， 该人群的正常功能可能表现为PCOS神经内分泌表型。然而，最近 有证据表明，类固醇激素信号不是直接在KNDy神经元水平上发生的， 暗示类固醇激素反馈受损发生在KNDy神经元上游的人群中。作为 KNDy神经元的传入神经元的身份在很大程度上是未知的，本研究的长期目标是表征 调节KNDy神经元活性的神经元群体的表型和功能作用，并确定 已识别神经元的变化是否有助于多囊卵巢综合征的病理生理学。为了实现这一目标，我们将 使用产前雄激素治疗诱发的多囊卵巢综合征小鼠模型。指导阶段 这项提议将包括转基因小鼠、狂犬病介导的肠道追踪的复杂组合 技术、全脑光学清晰度和三维分析确定上游KNDy神经元 并确定GnRH/LH高分泌受损是否是突触输入改变的结果 KNDy神经元(目标1)和/或改变KNDy神经元的传入活动(目标2)。在我的指导结束时 在这一阶段，我将获得过渡到独立所需的神经解剖学技术方面的专业知识 在我的领域，并接受了本提案独立阶段所需的实用技术培训。在目标3中，我 将使用化学遗传学和/或光遗传学工具来定义KNDy神经元调控的变化是否通过 传入种群足以增加GnRH/LH脉冲式释放。在《目标4》中，我将使用病毒媒介 确认传入神经元类固醇激素敏感性受损的缺失技术驱动下游 类固醇激素反馈受损和由此导致的不孕症的PCOS表型的变化和结果。 这些研究有可能识别对神经元控制至关重要的电路的新组件。 生育能力，并可能为成年后多囊卵巢综合征的治疗提供新的靶点，或防止 这种疾病在年轻女性中的发展。

Project Summary: Polycystic ovarian syndrome (PCOS) is the leading cause of infertility worldwide. The cardinal features of the syndrome are anovulatory and cystic ovaries, disrupted menstrual cycles and hyperandrogenism. The ovaries are controlled by a small group of neurons that reside in the hypothalamus, gonadotropin-releasing hormone (GnRH) neurons. Activity in these neurons regulate pulsatile luteinizing hormone (LH) release from the pituitary gland, which controls ovulation and sex steroid hormone production at the ovary. Steroid hormones, in turn, act in the brain through an afferent neuronal network to provide critical feedback to GnRH neurons. In many women with PCOS this feedback pathway is impaired, resulting in increased GnRH/LH pulse frequency which drives the downstream consequences of the syndrome. Neurons upstream from GnRH neurons that co-express the peptides Kisspeptin, Neurokinin B and Dynorphin (KNDy neurons) are heavily implicated in both steroid hormone feedback and GnRH/LH pulse generation, therefore, perturbations in the normal function of this population may manifest as the PCOS neuroendocrine phenotype. However, recent evidence indicates that steroid hormone signaling does not occur directly at the level of KNDy neurons, implicating impaired steroid hormone feedback occurs within a population upstream to KNDy neurons. As the identity of afferents to KNDy neurons is largely unknown, the long term goal of this research is to characterize the phenotype and functional roles of neuronal populations that regulate KNDy neuron activity, and, determine whether changes in the identified neurons contribute to the pathophysiology of PCOS. To achieve this, we will use a well characterized mouse model of PCOS induced by prenatal androgen treatment. The mentored phase of this proposal will include a sophisticated combination of transgenic mice, rabies-mediated tract tracing techniques, whole brain optical clearing and three-dimensional analysis to define the upstream KNDy neuronal populations and determine whether impaired GnRH/LH hypersecretion is the result of altered synaptic input to KNDy neurons (Aim 1) and/or altered activity of afferents to KNDy neurons (Aim 2). At the end of my mentored phase, I will have gained expertise in neuroanatomical techniques necessary for transitioning to independence in my field and trained in functional techniques required for the Independent phase of this proposal. In Aim 3, I will use chemogenetic and/or optogenetic tools to define whether changes in the regulation of KNDy neurons by afferent populations is sufficient to increase GnRH/LH pulsatile release. In Aim 4, I will use viral-mediated deletion techniques to confirm that impaired steroid hormone sensitivity in afferent neurons drives downstream changes and results in the PCOS phenotype of impaired steroid hormone feedback and resultant infertility. These studies have the potential to identify new components of the circuitry critical for the neuronal control of fertility, and may provide novel targets for the therapeutic treatment of PCOS in adulthood, or, to prevent the development of the disorder in young women.