Determining the topology and molecular profiles of nociceptive DRG neurons innervating distal colon and rectum

项目总结/摘要 慢性内脏痛是肠易激综合征（IBS）患者的主要症状， 占美国人口的15%。有效和可靠的治疗干预仍然不可用，尽管 内脏疼痛带来的巨大经济负担。肠易激综合征内脏痛的药物治疗是 其副作用大于治疗益处，很大程度上不令人满意。相反，神经调节（例如， 脊髓刺激）作为药物的替代品具有少得多的副作用。 背根神经节（DRG）神经调节的最新进展减轻了某些躯体和 神经性疼痛因此，背根神经节似乎是下一代神经调节的有希望的靶点。 治疗IBS相关内脏疼痛的器械。然而，缺少关于拓扑分布的知识 和神经支配结肠和直肠（结肠直肠）的功能特征性DRG神经元的分子谱， 尤其是结肠直肠伤害感受器。这严重阻碍了DRG的进一步发展 在治疗IBS的内脏痛中选择性影响DRG神经元子集的神经调节。我们的目标是 通过Ca 2+成像和单细胞成像，利用我们最近在光学电生理学方面的技术进步， 感觉神经元的转录组测定以表征结直肠癌的拓扑结构和分子谱 胸腰椎和腰骶DRG中的伤害感受器。 提出了三个具体目标。具体目标1将量化机械的拓扑分布， 对照组和延长组胸腰段和腰骶段背根神经节中的结肠直肠伤害性感受器 超敏反应具体目标2将量化结肠直肠沉默伤害感受器的拓扑分布， 胸腰段和腰骶段DRG在控制和延长结直肠过敏。第3章将 确定胸腰椎结直肠机械和沉默伤害感受器的分子特征， 腰骶DRG控制和延长结直肠过敏。通过建立一个高通量的光学 电生理学方法，我们将能够在功能上表征大量（>2000）结肠直肠DRG 神经元（包括伤害感受器），并揭示其拓扑分布在胸腰椎和腰骶DRG。 对结直肠伤害感受器的单细胞转录组分析将揭示化学治疗的有希望的靶点。 DRG的神经调节。这项研究的结果将指导下一代的设计 靶向DRG的神经调节装置，用于有效管理慢性内脏疼痛，同时最小化 脱靶副作用

Project Summary/Abstract Chronic visceral pain is the cardinal symptom of patients with irritable bowel syndrome (IBS) affecting up to 15% of the U.S. population. Efficacious and reliable therapeutic intervention is still unavailable despite the tremendous economic burden imposed by visceral pain. Pharmacological treatments of visceral pain in IBS are largely unsatisfactory with side effects outweighing therapeutic benefits. In contrast, neuromodulation (e.g., spinal cord stimulation) as an alternative to drugs has much fewer side effects. Recent advances in neuromodulation of the dorsal root ganglions (DRG) relieves certain somatic and neuropathic pain. Hence, the DRG appears to be a promising target for next-generation neuromodulatory devices to treat IBS-related visceral pain. However, knowledge is missing regarding the topological distribution and molecular profiles of functionally-characterized DRG neurons innervating the colon and rectum (colorectum), especially colorectal nociceptors. This has significantly hindered the further development of DRG neuromodulation that selectively affects a subset of DRG neurons in treating visceral pain in IBS. We aim to leverage our recent technical advances in optical electrophysiology via Ca2+ imaging and single-cell transcriptome assay of sensory neurons to characterize the topology and molecular profiles of colorectal nociceptors in the thoracolumbar and lumbosacral DRG. Three specific aims are proposed. Specific Aim 1 will quantify the topological distribution of mechano- nociceptors of the colorectum in the thoracolumbar and lumbosacral DRG in control and prolonged colorectal hypersensitivity. Specific Aim 2 will quantify the topological distribution of silent nociceptors of the colorectum in the thoracolumbar and lumbosacral DRG in control and prolonged colorectal hypersensitivity. Specific Aim 3 will define the molecular profiles of mechano- and silent nociceptors of the colorectum in the thoracolumbar and lumbosacral DRG in control and prolonged colorectal hypersensitivity. By establishing a high-throughput optical electrophysiology method, we will be able to functionally characterize a large number (>2000) of colorectal DRG neurons (including nociceptors) and reveal their topological distributions in thoracolumbar and lumbosacral DRG. The single-cell transcriptome analysis on colorectal nociceptors will reveal promising targets for chemical neuromodulation of the DRG. The outcomes of this research will guide the design of next-generation neuromodulatory devices that target DRG for effective management of chronic visceral pain while minimizing off-target side effects.