Hox genes in the development of respiratory circuits

7.项目摘要/摘要 呼吸是一种重要的运动行为，它依赖于哺乳动物的横隔肌收缩。频次 呼吸运动的幅度由位于脑干和脊髓中的神经网络控制 电源线。这些网络的退化会导致呼吸障碍，如中枢性睡眠呼吸暂停， 最终导致呼吸衰竭。我的长期目标是揭示呼吸系统回路的基本原理 这样我们就可以开始考虑呼吸功能障碍的替代治疗方法。一个 呼吸神经网络研究的难题是，尽管在以下方面取得了重大进展 确定脑干的节律回路、发育起源、分子同一性和 脊髓呼吸神经元的连通性仍不清楚。总体而言，拟议的研究旨在界定 脊椎呼吸系统网络组装的遗传和分子途径。我们最近做了 证明了颈髓内膈运动柱(PMC)神经元的发育 支配横隔膜，需要Hox5基因的持续活动。运动中缺乏Hox5基因的小鼠 神经元(MN)出生时就死于呼吸衰竭，并在PMC身份的多个方面表现出缺陷， 包括丛集、轴突引导和横隔膜神经支配。在该奖项的指导部分， Hox5基因在PMC MNS中的作用有待进一步研究。将进行差异基因表达分析 为了识别作用于Hox5蛋白下游的基因，以调节PMC的不同方面 发展(目标1)。此外，基于跨突触病毒的跟踪方法将被要求检查 从MNS中去除Hox5如何影响PMC运动前输入的建立(目标2)。在.期间 该奖项的独立阶段、HOX基因及其下游靶点在脊髓呼吸中的作用 将检查神经元间发育和连接(目标3)。解决这个问题将在很大程度上取决于 关于遗传学方法、跨突触回路标记技术和生理呼吸测试，其中 专业知识将在K99阶段获得。研究的指导部分将在 纽约大学医学中心的Dasen和Fishell实验室，一个出色的研究环境，将提供所有 拟议实验所需的设备和设施。此外，拉瓦尔大学的金基德博士将 担任顾问并将提供体积描记技术方面的培训。我已经组装了一个 委员会将监督我的进度，并在指导部分提供技术和智力投入 奖的获得者。我之前在分子神经科学方面的经验，再加上严格的训练计划， 将确保圆满完成拟议的研究目标，同时开展职业发展活动 在K99阶段的授奖将有助于平稳过渡到独立的职位。

7. Project summary/ Abstract Breathing is a vital motor behavior that relies on diaphragm muscle contractions in mammals. The frequency and amplitude of breathing movements is controlled by neural networks residing in the brainstem and spinal cord. Degeneration of these networks leads to respiratory disorders, such as central sleep apneas, and, eventually, respiratory failure. My long term goal is to uncover the basic principles underlying respiratory circuit assembly so that we can begin to consider alternative treatment methods for respiratory dysfunction. A conundrum in the study of respiratory neural networks is that while significant progress has been made in defining the rhythmogenic circuits in the brain stem, the developmental origins, molecular identity and connectivity of spinal cord respiratory neurons remain unknown. Overall, the proposed research aims to define the genetic and molecular pathways that underlie spinal respiratory network assembly. We have recently demonstrated that the development of phrenic motor column (PMC) neurons in the cervical spinal cord, which innervate the diaphragm, requires the sustained activity of Hox5 genes. Mice lacking Hox5 genes in motor neurons (MNs) die of respiratory failure at birth and exhibit defects in multiple aspects of PMC identity, including clustering, axon guidance and diaphragm innervation. During the mentored part of this award, the role of Hox5 genes in PMC MNs will be further explored. Differential gene expression analysis will be carried out in order to identify genes acting downstream of Hox5 proteins to regulate distinct aspects of PMC development (Aim 1). Additionally, transsynaptic virus-based tracing approaches will be implored to examine how Hox5 removal from MNs affects the establishment of premotor inputs to the PMC (Aim 2). During the independent phase of the award, the role of Hox genes and their downstream targets in spinal cord respiratory interneuron development and connectivity will be examined (Aim 3). Addressing this question will rely heavily on genetic approaches, transsynaptic circuit labeling techniques and physiological respiratory assays, in which expertise will be acquired during the K99 phase. The mentored part of the research will be performed at the Dasen and Fishell labs at NYU Medical Center, an outstanding research environment that will provide all the equipment and facilities required for the proposed experiments. In addition, Dr. Kinkead at Laval University will act as a consultant and will provide training in the technique of plethysmography. I have assembled a committee who will oversee my progress and provide technical and intellectual input during the mentored part of the award. My previous experience in molecular neuroscience, in combination with a rigorous training plan, will ensure the successful completion of the proposed research aims, while the career development activities during the K99 phase of the award will facilitate a smooth transition to an independent position.