Sensitization of developing sensory neurons after incision

切口后发育中的感觉神经元的敏化

• 批准号: 10606472
• 负责人: Michael P Jankowski
• 金额: $ 41.21万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10606472
• 关键词: AVIL gene; Absence of pain sensation; Acute; Acute Pain; Adolescent; Adult; Afferent Neurons; Animals; Behavior; Behavioral; Cells; Central Nervous System; Child; Childhood; Chronic; Clinical; Cutaneous; Data; Development; Dose; Excision; Gene Expression; Genetic Complementation Test; Genetic Transcription; Goals; Growth; Growth Hormone Receptor; Hypersensitivity; Immune; Inflammation; Injury; Knock-out; Life; Long-Term Effects; Macrophage; Mechanics; Mediating; MicroRNAs; Molecular; Molecular Analysis; Mus; Muscle; Neonatal; Nerve; Nervous System; Neurons; Newborn Animals; Nociception; Nociceptors; Operative Surgical Procedures; Pain; Pain management; Patients; Peripheral; Peripheral Nerves; Peripheral Nervous System; Persistent pain; Plasmids; Play; Postoperative Pain; Preparation; Reporting; Repression; Research; Rest; Role; Sensory; Serum Response Factor; Signaling Molecule; Site; Small Interfering RNA; Somatotropin; Spinal Cord; Structure of tibial nerve; Surgical incisions; System; Technology; Testing; Time; Tissues; Transgenic Mice; Up-Regulation; Western Blotting; Work; behavior test; chronic pain; design; early experience; experience; experimental study; genetic manipulation; growth hormone deficiency; hormonal signals; in vivo; injured; innovation; insight; knock-down; neonatal injury; neonatal mice; neonate; neuronal excitability; new therapeutic target; nociceptive response; novel; overexpression; pain patient; pain receptor; preclinical study; receptor; receptor expression; response; somatosensory; transcription factor

ABSTRACT: Approximately 15-20% of children experience persistent or chronic pain. However, compared to adults, we know relatively little about the mechanisms of pediatric pain development. A basic understanding of nociceptive processing in the immature nervous system is therefore crucial in order to develop more appropriate treatments for pain in children. Patients with growth hormone deficiency (GHD) may provide insight into this clinical problem. Patients with GHD often display pain at rest in addition to deficits in growth. Moreover, treatment of certain pain patients with GH provides analgesia. We have found that cutaneous inflammation and muscle incision in mice reduces GH in the injured tissues. Observed changes in gene expression, afferent function and pain-related behaviors during neonatal injury are blocked by treating mice with exogenous GH. New pilot data suggests that macrophage dependent sequestering of GH at the site of peripheral injury, subsequently reduces inhibitory microRNA expression (e.g. miR-133a) within nociceptors to increase transcription factor (e.g. serum response factor (SRF)) dependent upregulation of various receptors and channels that modulate afferent function and pain-related beahviors. The main goal of this proposal is to determine the molecular mechanisms of how GH levels regulate sensory neuron sensitization during muscle incision and how this may underlie acute and persistent neonatal hypersensitivity. Specific Aim 1 will use a novel ex vivo somatosensory recording preparations to determine the effects of macrophage or sensory neuron specific knockout of the GH receptor on the sensitization of sensory neurons in uninjured neonatal mice or animals with muscle incision. Specific Aim 2 will test whether knockdown of a transcription factor (SRF) or overexpression of a microRNA (miR-133a), that is thought to regulate receptor expression in neurons (and thereby modulate peripheral sensitization), modifies these same changes in afferent function after muscle incision using in vivo siRNA-mediated knockdown or plasmid based overexpression strategies in single peripheral nerves in conjunction with ex vivo recording. Each of these two aims will be complemented by analysis of ongoing and evoked hypersensitivity. Finally, Specific Aim 3 will use behavioral analyses and/or ex vivo recording to determine the influence of localized GH treatments, GHr KO, SRF inhibition or miR-133a overexpression in neonatally incised mice on the prolonged effects to subsequent adolescent incision. These experiments will allow a better understanding of the unique mechanisms in primary sensory neurons by which peripheral GH levels regulate afferent sensitization and neonatal pain development. These studies will facilitate understanding of the transition from acute to chronic pediatric pain, and will allow us to determine the utility of GH as a pain therapy for children. This work may also lead to the design of more suitable treatments for pediatric pain that target specific pain receptor(s), signaling molecule(s) or afferent subtype(s).

摘要：大约 15-20% 的儿童经历持续性或慢性疼痛。然而，相比 对于成年人来说，我们对儿科疼痛发展的机制知之甚少。基本了解 因此，未成熟的神经系统中的伤害感受处理对于发展更多的能力至关重要。 儿童疼痛的适当治疗。生长激素缺乏症 (GHD) 患者可能会提供见解 进入这个临床问题。 GHD 患者除了生长障碍外，还经常表现出休息时疼痛。 此外，用 GH 治疗某些疼痛患者可提供镇痛作用。我们发现皮肤 小鼠的炎症和肌肉切口会减少受伤组织中的生长激素。观察到的基因变化 治疗小鼠可阻断新生儿损伤期间的表达、传入功能和疼痛相关行为 与外源性GH。新的试验数据表明，巨噬细胞依赖性 GH 在位点的隔离 外周损伤，随后降低伤害感受器内的抑制性 microRNA 表达（例如 miR-133a） 增加各种受体的转录因子（例如血清反应因子（SRF））依赖性上调 以及调节传入功能和疼痛相关行为的通道。该提案的主要目标是 确定 GH 水平如何调节肌肉过程中感觉神经元敏化的分子机制 切口以及这如何可能导致急性和持续性新生儿过敏。具体目标 1 将使用 新型离体体感记录制剂，以确定巨噬细胞或感觉的影响 神经元特异性敲除 GH 受体对未受伤新生小鼠感觉神经元敏感性的影响 或有肌肉切口的动物。具体目标 2 将测试转录因子 (SRF) 或 microRNA (miR-133a) 的过度表达，被认为可以调节神经元中的受体表达（以及 从而调节外周敏化），改变肌肉后传入功能的这些相同变化 使用体内 siRNA 介导的敲低或基于质粒的过表达策略进行切口 周围神经与离体记录相结合。这两个目标中的每一个都将得到补充 分析持续的和诱发的超敏反应。最后，具体目标 3 将使用行为分析和/或 ex 体内记录以确定局部 GH 治疗、GHr KO、SRF 抑制或 miR-133a 的影响 新生小鼠中的过度表达对随后的青少年切口的长期影响。这些 实验将有助于更好地理解初级感觉神经元的独特机制 外周 GH 水平调节传入敏化和新生儿疼痛的发展。这些研究将有助于 了解从急性到慢性儿科疼痛的转变，并使我们能够确定 GH 作为儿童疼痛疗法。这项工作还可能导致设计更合适的治疗方法 针对特定疼痛受体、信号分子或传入亚型的儿科疼痛。