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，在发育早期触觉输入的改变可能 对健康和行为造成长期影响。在哺乳动物中，无痛性触摸是通过低- 阈值机械感受器（LTMR），支配皮肤并传递触觉的外周感觉神经元 通过在脊髓和脑干中形成突触将信息传递到中枢神经系统（CNS）。如何 来自周边的机械或分子线索影响LTMR及其下游的发展 电路仍然知之甚少。特别是，中枢神经系统的发展机制 LTMR参与的电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。这项拟议中的工作将利用老鼠的遗传学、解剖学、 电生理学和分子方法来研究发育神经活动的作用， 皮肤类型特异性信号，其塑造躯体感觉神经元的结构和功能发育， 他们的下游电路在目标1中，圣地亚哥博士将使用条件离子通道突变体来定义 在机械感觉终末器官结构成熟过程中的自发和诱发活动 外围目标2将进入中枢神经系统，并评估外周介导的活动的要求， LTMR中枢靶向和突触形成，以及在躯体定位图形成期间。圣地亚哥医生会 使用一种新的小鼠转基因系在限定的发育过程中短暂沉默体感神经元 在恢复触觉和测量中枢神经元对触觉刺激的反应之前，在 目的3，圣地亚哥博士将使用靶向特异性RNA测序的躯体感觉神经元，手术 操纵和遗传方法来确定目标依赖的分子机制， 皮肤控制LTMR身份和连接。这些拟议中的实验将与一项科学研究相结合， 电生理学和生物信息学数据分析方面的培训计划，以及职业发展计划 准备让圣地亚哥博士成为一名独立研究员。技术和概念指导 设计和执行电生理和RNA测序实验将由该小组提供 候选人召集的顾问包括布鲁斯比恩博士、陈金飞博士、丽莎古德里奇博士、 和迈克尔·格林伯格候选人的导师，大卫金蒂博士，将监督指导阶段的 通过定期会议奖励，并确保圣地亚哥博士的培训充分准备她过渡到一个 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 体感系统的发展，并准备她领导一个独立的研究小组，解决 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.