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.

角膜是体内神经支配最密集的组织，疼痛是由角膜引起的主要体验。 角膜刺激。虽然生理性角膜疼痛（伤害性疼痛）可以保护眼睛免受伤害， 炎症和/或神经损伤可导致长期或慢性角膜疼痛。角膜传入代表 多样化的神经元群体，具有与维持眼部健康相关的特殊特性。完整的 这些神经元的多样性及其对损伤的反应尚不清楚。第一组实验将 确定三叉神经节 (TG) 中小鼠角膜神经元的 mRNA 转录特征及其 对角膜损伤的转录反应并与细胞类型特异性转录和表观基因组进行比较 人类 TG 神经元的特征。众所周知，角膜传入神经投射到脊柱的两个主要区域 三叉神经核（Vsp），每个在伤害感受和维持角膜稳态方面具有不同的作用。我们有 初步数据显示了臂旁核外侧核 (lPBN) 的额外投影，该区域 对于调节对厌恶刺激的复杂动机情感反应至关重要。对角膜的贡献 疼痛未知。第二组实验将检查 lPBN 中角膜输入的中央处理。 我们将确定角膜->lPBN初级传入投射对角膜伤害性的贡献 lPBN 神经元在角膜伤害性和慢性疼痛行为中的反应和功能。额外的 研究将进行单核转录组分析，以确定角膜激活的分子谱 脑干神经元，然后进行多重原位杂交，以提供区域的空间分辨率 接收直接角膜传入输入。角膜还具有常驻角膜白细胞 (RCL) 位于角膜神经附近，表明角膜中存在神经免疫串扰的可能性 角膜。然而，目前对于通过角膜神经直接调节 RCL 的认识有限，或者 RCL对角膜神经功能的影响。第三组实验将表征细胞 参与导致周围神经的神经免疫串扰的群体和分子机制 角膜过敏。与小鼠角膜疼痛相关的角膜单细胞 mRNA 转录特征 模型将用于识别伤害感受器敏化背后的转录变化。穿越这些 具有角膜传入转录谱的免疫细胞转录本将为配体-受体提供证据 对。体外研究将证实已确定的调节剂使 TG 神经元敏感的能力，以及 将使用行为和离体电生理学来评估功能意义。雇用一个 多学科方法，这些实验将提供细胞和分子的全面分析 伤害性和慢性角膜疼痛的机制，导致识别新的途径和 治疗。