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，与 对于成年人来说，我们对儿童疼痛发生的机制知之甚少。对…的基本了解 因此，未成熟神经系统中的伤害性处理对于发育成更多的 儿童疼痛的适当治疗。生长激素缺乏症(GHD)患者可能会提供洞察力 这一临床问题。GHD患者除了生长发育障碍外，还经常表现出休息时的疼痛。 此外，用生长激素治疗某些疼痛患者可以起到止痛作用。我们已经发现了皮肤 小鼠的炎症和肌肉切开减少了受损组织中的生长激素。观察到的基因变化 治疗小鼠可阻断新生损伤期间的表达、传入功能和疼痛相关行为 外源生长激素。新的试点数据表明，巨噬细胞依赖的生长激素隔离部位 外周损伤，随后将伤害性感受器内抑制的microRNA表达(例如miR-133a)减少到 增加转录因子(如血清反应因子)依赖的各种受体的上调 以及调节传入功能和疼痛相关行为的通道。这项提议的主要目标是 确定生长激素水平调节肌肉中感觉神经元敏化的分子机制 切开，以及这可能是急性和持续性新生儿过敏的基础。特定目标1将使用 用于确定巨噬细胞或感觉效应的新型体外体感记录制剂 神经元特异性敲除生长激素受体对未损伤新生小鼠感觉神经元的敏化作用 或有肌肉切开的动物。特定目标2将测试转录因子(SRF)或 一种microRNA(miR-133a)的过度表达，被认为调节神经元中受体的表达(和 从而调节外周敏感化)，改变肌肉后传入功能的这些相同变化 用体内siRNA介导的敲除或基于质粒的过度表达策略在单个 外周神经结合体外记录。这两个目标中的每一个都将得到补充 正在进行的和诱发的过敏症分析。最后，《特定目标3》将使用行为分析和/或EX 活体记录以确定局部GH处理、Ghr KO、SRF抑制或miR-133a的影响 新生切割小鼠的过度表达对随后青春期切割的延长影响。这些 实验将使我们能够更好地理解初级感觉神经元中的独特机制 外周生长激素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，并将使我们能够确定 GH作为儿童的疼痛疗法。这项工作也可能导致设计出更适合的治疗方法 针对特定疼痛受体(S)、信号分子(S)或传入亚型(S)的儿童疼痛。