Enhancing Respiratory Motor Function after Spinal Cord Injury

增强脊髓损伤后的呼吸运动功能

• 批准号: 10675888
• 负责人: Carlos B Mantilla
• 金额: $ 77.56万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2027-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10675888
• 关键词: Affect; Affinity; Alleles; Animal Model; Behavior; Brain-Derived Neurotrophic Factor; Breathing; Cervical spinal cord injury; Chronic; Complex; Contusions; Development; Glutamates; Goals; Hydrogels; Impairment; In Situ Hybridization; Injury; Ipsilateral; Knock-in; Label; Laboratories; Mammals; Modeling; Morbidity - disease rate; Motor; Motor Neurons; Muscle; Muscle function; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; Neuronal Plasticity; Patients; Persons; Phosphotransferases; Physiology; Presynaptic Terminals; Rattus; Recovery; Recovery of Function; Reporting; Research; Research Personnel; Resolution; Respiratory Diaphragm; Role; Signal Transduction; Site; Spinal Cord Contusions; Spinal cord injury; Structure of phrenic nerve; Synapses; Techniques; Time; Treatment Factor; United States; confocal imaging; density; experience; gamma-Aminobutyric Acid; innovation; insight; loss of function; mRNA Expression; mortality; neuron loss; neuronal survival; neuroprotection; novel; novel therapeutic intervention; postsynaptic; preservation; pressure; presynaptic; receptor; receptor expression; recruit; respiratory

ABSTRACT The proposed studies focus on the role of BDNF/TrkB signaling in promoting phrenic motor neuron (PhMN) survival and pre- and postsynaptic neuroplasticity to enhance functional recovery after cervical spinal cord injury (cSCI). We will leverage our extensive experience using two well-established models of incomplete cSCI, i.e., C2 hemisection - C2SH and C4 contusion injury - C4CI to explore neuroplasticity at PhMNs. We will also bring years of experience examining diaphragm muscle (DIAm) motor unit physiology, recognizing the importance of PhMN size in the recruitment of DIAm motor units. Stratifying the effects of BDNF/TrkB signaling on pre- and postsynaptic neuroplasticity in PhMNs of varying size is conceptually innovative and provides valuable mechanistic insight. The “Size Principle” is a key concept in neuromotor control physiology, but until now it has been difficult to directly include motor neuron size as a critical variable. We hypothesize that there are size- dependent differences in BDNF/TrkB signaling effects on pre- and postsynaptic neuroplasticity after cSCI. The proposed studies will provide novel information about PhMN neuroplasticity underlying functional recovery of inspiratory and post-inspiratory DIAm activity that will inform development of novel therapeutic approaches to enhance recovery of DIAm function in patients with incomplete cSCI. The proposed studies will utilize a comprehensive array of innovative techniques, many developed in our lab. In all 3 specific aims, we will examine the effects of modulating BDNF/TrkB signaling using a gain/loss of function approach utilizing intrathecal BDNF or TrkB-Fc treatment and a novel TrkBF616A rat with a 1NMPP1 sensitive knock-in allele that rapidly and selectively inhibits TrkB kinase activity. In Aim 1, we will use high resolution confocal imaging to explore the role of BDNF/TrkB signaling on the recovery of Glu and Gly/GABA presynaptic terminals on retrogradely labeled PhMNs of varying size following C2SH. In Aim 2, we will employ a novel RNAscope in situ hybridization technique to simultaneously explore changes in NMDA, Gly and GABAA receptor mRNA expression in PhMNs of varying size. In Aim 3, we will examine the neuroprotective effects (PhMN survival) of BDNF/TrkB signaling following C4CI. In addition, we will examine the effect of BDNF/TrkB signaling on Glu and Gly/GABA synaptic input and NMDA, Gly and GABAA receptor mRNA expression (pre- and postsynaptic neuroplasticity) in surviving PhMNs above (i.e., C3) and below (i.e., C5) the C4CI injury.

抽象的 拟议的研究重点是 BDNF/TrkB 信号在促进膈运动神经元 (PhMN) 中的作用 生存和突触前和突触后神经可塑性，以增强颈脊髓损伤后的功能恢复 （cSCI）。我们将利用我们丰富的经验，使用两个成熟的不完整 cSCI 模型，即 C2 半切 - C2SH 和 C4 挫伤 - C4CI 以探索 PhMN 的神经可塑性。我们还将带来 多年检查膈肌 (DIAm) 运动单位生理学的经验，认识到 DIAm 运动单位招募中的 PhMN 大小。分层 BDNF/TrkB 信号对前和后的影响 不同大小的 PhMN 的突触后神经可塑性在概念上是创新的，并提供了有价值的 机械的洞察力。 “尺寸原理”是神经运动控制生理学中的一个关键概念，但到目前为止，它还没有被广泛应用。 很难直接将运动神经元大小作为关键变量。我们假设有大小- cSCI 后 BDNF/TrkB 信号传导对突触前和突触后神经可塑性影响的依赖性差异。这 拟议的研究将提供有关 PhMN 神经可塑性的新信息，这些信息是功能恢复的基础 吸气和吸气后 DIAm 活动将为开发新的治疗方法提供信息 促进不完全性 cSCI 患者 DIAm 功能的恢复。 拟议的研究将利用一系列全面的创新技术，其中许多技术是我们开发的 实验室。在所有 3 个具体目标中，我们将检查使用增益/损失调节 BDNF/TrkB 信号传导的效果 利用鞘内 BDNF 或 TrkB-Fc 治疗和具有 1NMPP1 的新型 TrkBF616A 大鼠的功能方法 敏感的敲入等位基因，可快速、选择性地抑制 TrkB 激酶活性。在目标 1 中，我们将使用高 分辨率共聚焦成像探索 BDNF/TrkB 信号传导对 Glu 和 Gly/GABA 恢复的作用 C2SH 后逆行标记的不同大小的 PhMN 上的突触前末梢。在目标 2 中，我们将采用 新型 RNAscope 原位杂交技术可同时探索 NMDA、Gly 和 GABAA 的变化 不同大小的 PhMN 中受体 mRNA 的表达。在目标 3 中，我们将检查神经保护作用 C4CI 后 BDNF/TrkB 信号传导（PhMN 存活）。此外，我们将检查 BDNF/TrkB 的效果 Glu 和 Gly/GABA 突触输入以及 NMDA、Gly 和 GABAA 受体 mRNA 表达（前和 突触后神经可塑性）在 C4CI 损伤上方（即 C3）和下方（即 C5）的幸存 PhMN 中。