Peripheral Activity-Dependent and Molecular Mechanisms that Control Somatosensory System Development

项目摘要 触觉对生命是必不可少的，在发育早期触觉感觉输入的变化可能 对健康和行为造成长期后果。在哺乳动物中，非疼痛的触摸是通过低位触觉来检测的 阈值机械感受器(LTMR)，支配皮肤和传递触觉的外周感觉神经元 通过在脊髓和脑干形成突触向中枢神经系统(CNS)传递信息。多么 来自外围的机械或分子信号影响LTMR及其下游的发展 人们对电路仍然知之甚少。尤其是，中央的发展机制 LTMR参与的回路和大脑的躯体组织和不成比例的反应 身体不同部位的接触仍不清楚。这项拟议的工作将利用小鼠的基因、解剖学和 电生理学和分子方法研究发育神经活动和 形成躯体感觉神经元结构和功能发育的皮肤类型特异性信号 它们的下游电路。在目标1中，圣地亚哥博士将使用条件性离子通道突变来定义 大鼠机械感觉末梢器官结构成熟过程中的自发和诱发活动 外围设备。目标2将进入中枢神经系统，并评估在 LTMR中枢靶向和突触的形成，以及体位图的形成。圣地亚哥医生会 使用一种新的小鼠转基因品系在特定的发育过程中瞬时沉默体感神经元 在恢复触觉和测量中枢神经元对触觉刺激的反应之前的几个时期。在……里面 目标3，圣地亚哥博士将使用目标特定的体感神经元RNA测序，外科手术 操纵和遗传方法，以确定线索进入的靶标依赖的分子机制 皮肤控制LTMR身份和连接性。这些拟议的实验将与科学的 电生理学和生物信息数据分析方面的培训计划以及职业发展计划 让圣地亚哥博士做好成为独立研究员的准备。关于以下方面的技术和概念指导 设计和执行电生理和RNA测序实验将由该团队提供 候选人召集的顾问包括布鲁斯·宾博士、陈钦飞博士、丽莎·古德里奇博士、 还有迈克尔·格林伯格。候选人的导师大卫·金蒂博士将监督 通过定期会议颁奖，并确保圣地亚哥博士的培训为她过渡到 独立的立场。总之，拟议的研究和培训计划将使圣地亚哥博士能够 关于外周介导的活动和分子线索在脑内的作用的重要发现 开发体感系统，并准备领导一个独立的研究小组处理 神经发育中的突出问题。

Project Summary The sense of touch is essential for life, and alterations in tactile sensory inputs early in development may cause long-term consequences on health and behavior. In mammals, non-painful touch is detected by low- threshold mechanoreceptors (LTMRs), peripheral sensory neurons that innervate the skin and relay tactile information to the central nervous system (CNS) by forming synapses in the spinal cord and brainstem. How mechanical or molecular cues from the periphery influence the development of LTMRs and their downstream circuits remains poorly understood. In particular, the developmental mechanisms underlying the central circuitry engaged by LTMRs and the brain's somatotopically organized and disproportionate responses to touch of different body regions remain unclear. The proposed work will use mouse genetic, anatomical, electrophysiological, and molecular approaches to investigate the role of developmental neural activity and skin type-specific signals that shape the structural and functional development of somatosensory neurons and their downstream circuits. In Aim 1, Dr. Santiago will use conditional ion channel mutants to define the role of spontaneous and evoked activity during the maturation of mechanosensory end organ structures in the periphery. Aim 2 will move into the CNS and assess the requirement for peripherally-mediated activity during LTMR central targeting and synapse formation, as well as during somatotopic map formation. Dr. Santiago will use a new mouse transgenic line to transiently silence somatosensory neurons during defined developmental periods, before restoring touch sensation and measuring the responses of central neurons to tactile stimuli. In Aim 3, Dr. Santiago will use target-specific RNA sequencing of somatosensory neurons, surgical manipulations, and genetic approaches to identify target-dependent molecular mechanisms by which cues in the skin control LTMR identity and connectivity. These proposed experiments will be paired with a scientific training plan in electrophysiology and the analysis of bioinformatic data, as well as a career development plan preparing Dr. Santiago to become an independent researcher. Technical and conceptual guidance on designing and performing electrophysiological and RNA sequencing experiments will be provided by the team of consultants that the candidate has assembled that includes Drs. Bruce Bean, Chinfei Chen, Lisa Goodrich, and Michael Greenberg. The candidate's mentor, Dr. David Ginty, will supervise the mentored phase of the award through regular meetings and ensure that Dr. Santiago's training fully prepares her to transition to an independent position. Together, the proposed research and training plan will enable Dr. Santiago to make important discoveries concerning the role of peripherally-mediated activity and molecular cues in somatosensory system development and prepare her to lead an independent research group addressing outstanding questions in neural development.