Central and Peripheral Mechanisms of Corneal Pain

角膜疼痛的中枢和外周机制

• 批准号: 10595408
• 负责人: Pedram Hamrah
• 金额: $ 133.57万
• 依托单位: UNIVERSITY OF NEW ENGLAND
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-30 至 2027-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10595408
• 关键词: Acute; Address; Affective; Afferent Neurons; Anatomy; Aversive Stimulus; Behavior; Behavioral; Brain Stem; Brain region; Cell Nucleus; Cells; Chronic; Complex; Cornea; Corneal Diseases; Corneal Injury; Corneal pain; Data; Debridement; Disease; Dry Eye Syndromes; Electrophysiology (science); Excision; Eye Injuries; Gene Expression Profile; Genetic Transcription; Health; Homeostasis; Human; Immune; In Situ Hybridization; In Vitro; Inflammation; Injury; Intervention; Knowledge; Lacrimal gland structure; Lateral; Lead; Leukocytes; Ligands; Measures; Messenger RNA; Molecular; Molecular Profiling; Motivation; Mus; Nerve; Neuroimmune; Neurons; Neuropathy; Nociception; Nociceptors; Pain; Pathway interactions; Peripheral; Peripheral Nerves; Physiological; Population; Population Heterogeneity; Property; Regulation; Resolution; Role; Signal Transduction; Structure of trigeminal ganglion; Structure of trigeminal nerve spinal tract nucleus; Tissues; Transcript; base; cell type; chronic pain; epigenomics; experience; experimental study; interdisciplinary approach; nerve damage; nerve injury; nociceptive response; novel; ocular surface; optogenetics; pain behavior; pain model; parabrachial nucleus; receptor; response; response to injury; transcriptome

The cornea is the most densely innervated tissue in the body, and pain is the primary experience resulting from corneal stimulation. While physiological corneal pain (nociceptive pain) protects the eye from injury, inflammation and/or nerve damage can result in prolonged or chronic corneal pain. Corneal afferents represent a diverse population of neurons, with specialized properties related to maintaining ocular health. The full diversity of these neurons, and their responses to injury are unknown. The first set of experiments will determine the mRNA transcript signatures of mouse corneal neurons in the trigeminal ganglion (TG) and their transcriptional responses to corneal injury and compare with cell-type-specific transcriptional and epigenomic signatures of human TG neurons. Corneal afferents are known to project to two main regions in the spinal trigeminal nucleus (Vsp), each with distinct roles in nociception and maintaining corneal homeostasis. We have preliminary data demonstrating an additional projection to the lateral parabrachial nucleus (lPBN), a region critical in regulating complex motivational-affective responses to aversive stimuli. Its contribution to corneal pain is unknown. The second set of experiments will examine central processing of corneal input in the lPBN. We will determine the contribution of corneal->lPBN primary afferent projections to corneal nociceptive responses and the function of lPBN neurons in corneal nociceptive and chronic pain behaviors. Additional studies will perform single-nucleus transcriptome analysis to identify molecular profiles of corneal-activated brainstem neurons, followed by multiplex in situ hybridization to provide spatial resolution in regions that receive direct corneal afferent input. The cornea is also endowed with resident corneal leukocytes (RCLs) residing in close proximity to corneal nerves, suggesting the possibility of neuro-immune crosstalk in the cornea. However, current knowledge is limited on possible direct regulation of RCLs through corneal nerves, or the influence of RCLs on corneal nerve function. The third set of experiments will characterize the cell populations and molecular mechanisms involved in neuroimmune crosstalk resulting in peripheral nerve sensitization in the cornea. Corneal single cell mRNA transcript signatures associated in murine corneal pain models will be used to identify transcriptional changes that underly nociceptor sensitization. Crossing these immune cell transcripts with transcript profiles of corneal afferents will provide evidence for ligand-receptor pairs. In vitro studies will confirm the ability of the identified modulators to sensitize TG neurons, and the functional significance will be assessed using behavior and ex vivo electrophysiology. Employing a multidisciplinary approach, these experiments will provide a comprehensive analysis of cellular and molecular mechanisms of nociceptive and chronic corneal pain, leading to the identification novel pathways and treatments.

角膜是体内最密集的神经组织，疼痛是由 角膜刺激。生理角膜疼痛（伤害感受性疼痛）可保护眼睛免受损伤，但 炎症和/或神经损伤可能会导致长时间或慢性角膜疼痛。角膜传入代表 多种神经元种群，具有与维持眼部健康有关的专门特性。完整 这些神经元的多样性及其对伤害的反应尚不清楚。第一组实验将 确定三叉神经节（TG）中小鼠角膜神经元的mRNA转录标志及其 对角膜损伤的转录反应，并与细胞型特异性转录和表观基因组相比 人类TG神经元的签名。已知角膜传入将投射到脊柱的两个主要区域 三叉神经核（VSP），每个核在伤害感受和维持角膜稳态中都有不同的作用。我们有 初步数据证明了对侧旁核（LPBN）的额外投影，一个区域 在调节对厌恶刺激的复杂动机反应中至关重要。它对角膜的贡献 疼痛是未知的。第二组实验将检查LPBN角膜输入的中央处理。 我们将确定角膜 - > lpbn主要传入投影对角膜伤害感受的贡献 LPBN神经元在角膜伤害和慢性疼痛行为中的反应和功能。额外的 研究将执行单核转录组分析，以鉴定角膜激活的分子特征 脑干神经元，然后进行多重原位杂交，以提供空间分辨率 接收直接的角膜传入输入。角膜还具有常驻角膜白细胞（RCLS） 居住在角膜神经附近，表明在 角膜。但是，当前的知识受到通过角膜神经对RCL的直接调节的限制，或 RCL对角膜神经功能的影响。第三组实验将表征单元格 与神经免疫串扰有关的种群和分子机制导致周围神经 角膜中的敏化。角膜单细胞mRNA转录本与鼠角膜疼痛相关的特征 模型将用于识别基础伤害感受器敏化的转录变化。越过这些 具有角膜传入的转录物谱的免疫细胞转录本将为配体受体的证据提供证据 成对。体外研究将证实已鉴定的调节剂使TG神经元敏感的能力，以及 功能显着性将使用行为和离体电生理学评估。雇用 多学科方法，这些实验将提供对细胞和分子的全面分析 伤害性和慢性角膜疼痛的机制，导致鉴定新途径和 治疗。