Neuroskeletal crosstalk in load-induced bone formation

项目摘要/摘要 在人类和临床前模型中，周围神经功能障碍与骨骼脆性有关。 虽然本体感觉缺陷在增加骨折风险中起着重要作用，但局部神经支配的丧失可能 消耗骨骼中对骨骼动态平衡至关重要的神经因子。这给维护带来了新的挑战 神经病患者和接受神经修饰治疗的患者的骨骼健康。具体来说，它可能会 影响负重运动的治疗效果。通过锻炼来机械加载骨骼是一种 对骨骼健康的明确要求。长骨受压导致骨骼重塑 加大力度。此外，骨细胞在加载后会分泌神经营养信号，这可能会促进神经 向骨骼发芽，改变内源性骨骼神经支配模式。考虑到这种情况的出现 神经在骨骼代谢中的作用，局部神经骨骼信号可能需要促进负荷诱导 骨形成。这项提议的中心目标是研究神经骨骼的可塑性和必要性。 骨骼对压缩负荷的合成代谢反应中的串扰。为了实现这一点，拟议的研究 分为两个目标。在目标1中，涉及负荷诱导骨形成的新的神经骨骼生态位将是 已定义。为了研究在骨骼适应过程中天然神经骨骼生态位是如何改变的，一个为期5天的 将在小鼠身上进行体内轴向压缩方案以诱导板层骨形成，随后 胫骨的组织学和成像。骨中的神经将使用新的泛神经元Baf53b-Ai9进行映射 小鼠和免疫组织化学染色检测神经亚型。此外，局部NGF和WNT1基因的表达将 通过原位杂交将其与已定义的神经骨骼生态位相关联。要研究空间 轴突、矿化表面和基因表达的定位和相对数量--一种新的图像分析方法 将使用工作流(RaDialQuant)。在目标2中，这些神经骨骼生态位对于负荷诱导的必要性 将对骨形成进行评估。为了验证这一点，将通过评估建立一个胫骨失神经模型。 在股神经和/或坐骨神经切除一周后，使用所采用的成像技术的神经元丢失 目的1.为了检验骨骼适应中神经支配的必要性，我们将对后肢进行相应的神经支配 在目标1中的循环轴向压缩之前。将使用目标1中的技术来隔离载荷的影响 以及去神经对轴突密度、矿物质结合和基因表达的影响。职业生涯的长期目标是 申请人将经营一家独立的研究实验室。除了研究计划外，培训计划还包括 旨在通过开发新的技术技能、指导和关键综合来实现这一目标 文学。这项为期两年的奖学金将在华盛顿大学医学院 Erica Scheller博士和Matthew Silva博士的指导，具有神经骨骼生物学和骨骼方面的专业知识 分别是生物力学。

PROJECT SUMMARY/ABSTRACT Peripheral nerve dysfunction is associated with skeletal fragility in humans and in preclinical models. While proprioceptive deficits play a significant role in increased fracture risk, loss of local innervation may deplete bone of neuronal factors critical for skeletal homeostasis. This presents new challenges for maintaining bone health in patients with neuropathy and those undergoing nerve-modifying treatments. Specifically, it may affect the therapeutic efficacy of weight-bearing exercise. Mechanically loading bone through exercise is a well-established requirement for bone health. Compression of long bones results in skeletal remodeling to increase strength. In addition, bone cells secrete neurotrophic cues after loading that may facilitate nerve sprouting towards the skeleton, modifying endogenous skeletal innervation patterns. Considering this emerging role of nerves in skeletal metabolism, local neuroskeletal signaling may be required to facilitate load-induced bone formation. The central goal of this proposal is to investigate the plasticity and necessity of neuroskeletal crosstalk in the anabolic response of bone to compressive loading. To accomplish this, the proposed research is divided into two aims. In Aim 1, novel neuroskeletal niches involved in load-induced bone formation will be defined. To investigate how native neuroskeletal niches are modified during skeletal adaptation, a 5-day regimen of in vivo axial compression will be conducted on mice to induce lamellar bone formation, followed by histology and imaging of the tibia. Nerves in bone will be mapped using a novel pan-neuronal Baf53b-Ai9 reporter mouse and immunostaining for nerve subtypes. In addition, local Ngf and Wnt1 gene expression will be mapped in relation to defined neuroskeletal niches using in situ hybridization. To study the spatial localization and relative quantities of axons, mineralizing surface, and gene expression, a novel image analysis workflow (RadialQuant) will be used. In Aim 2, the necessity of these neuroskeletal niches for load-induced bone formation will be evaluated. To test this, a model of tibial denervation will be developed by evaluating neuronal loss after one-week of femoral and/or sciatic neurectomy using the imaging techniques employed in Aim 1. To test the necessity of innervation in skeletal adaptation, the hindlimb will be denervated accordingly prior to cyclic axial compression as in Aim 1. Techniques from Aim 1 will be used isolate the effect of loading and denervation on axon density, mineral apposition, and gene expression. The long-term career goal of the applicant is to run an independent research laboratory. In addition to the research plan, the training plan is designed to achieve this goal through development of new technical skills, mentorship, and critical synthesis of literature. The two-year fellowship will be conducted at the Washington University School of Medicine under the mentorship of Dr. Erica Scheller and Dr. Matthew Silva, with expertise in neuroskeletal biology and bone biomechanics, respectively.