Evaluating neural circuitry of the bone marrow

项目概要： 骨髓是造血的主要场所，所有的血细胞都从骨髓中产生。 造血干细胞（HSCs）的调控分化。研究报告 申请人的实验室已经揭示了交感神经支配的关键功能 神经系统（SNS）在HSC从骨髓流出中的作用。SNS神经需要 诱导HSC的昼夜释放以及成熟造血干细胞的昼夜募集， 白细胞转移到外周。此外，骨髓也受肽能神经支配， 感觉纤维在造血中的功能尚不清楚。在本申请中，我们 提出一个为期3年的实验计划，以提高我们对 骨髓的神经解剖学和神经生理学。具体目标1： 描述骨髓中感觉神经的功能。我们将定义函数 使用免疫荧光成像和跨神经元病毒道追踪的神经回路， 并评估感觉和SNS纤维之间的信号的相互作用， 药理学和遗传学模型系统。在具体目标2中，我们将确定 在骨髓中传递SNS神经信号的细胞间转导途径。我们将 鉴定接受肾上腺素能信号介导ROS振荡的基质细胞类型 其可以代表神经信号传播的重要环节。具体目标 3将利用内源性神经回路来改善造血再生。我们将 使用腺病毒转导建立选择性骨髓DREADD，这将导致 器官特异性神经激活以增强遗传毒性损伤后的再生 例如电离辐射或化学疗法。内源性神经回路的操作 可能确实提供了一个有用的未来战略，以加速造血再生。 !

PROJECT SUMMARY: The bone marrow is the major site of hematopoiesis where all blood cells emerge from the regulated differentiation of hematopoietic stem cells (HSCs). Studies from the applicant’s laboratory have uncovered key functions for innervation of the sympathetic nervous system (SNS) in the egress of HSCs from marrow. SNS nerves are required to entrain the circadian release of HSCs and also the circadian recruitment of mature leukocytes to the periphery. In addition, the bone marrow is also innervated by peptidergic sensory fibers whose functions in hematopoiesis remain unclear. In this application, we propose a 3-year experimental plan that will advance our knowledge on the neuroanatomy and neurophysiology of the bone marrow. In Specific Aim 1, we will characterize the functions of sensory nerves in the marrow. We will define the functional neural circuits using immunofluorescence imaging and transneuronal viral tract tracing, and evaluate the interplay of signals between sensory and SNS fibers using pharmacological and genetic model systems. In Specific Aim 2, we will identify the intercellular transduction pathways that relay SNS nerve signals in bone marrow. We will identify the stromal cell types that receive adrenergic signals mediating ROS oscillations which may represent an important link for the propagation of neural signals. Specific Aim 3 will harness endogenous neural circuits to improve hematopoietic regeneration. We will establish selective bone marrow DREADDs using adenoviral transduction that will lead to organ-specific neural activation to enhance regeneration following genotoxic insults such as ionizing irradiation or chemotherapy. Manipulation of endogenous neural circuits may indeed provide a useful future strategy to accelerate hematopoietic regeneration. !