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

项目摘要/摘要 慢性内脏疼痛是肠易激综合征(IBS)患者的主要症状，影响多达 占美国人口的15%。有效和可靠的治疗干预仍然不可用，尽管 内脏疼痛造成的巨大经济负担。肠易激综合征内脏痛的药物治疗 很大程度上不令人满意，副作用大于治疗益处。相反，神经调节(例如， 脊髓刺激)作为药物的替代品，副作用要少得多。 背根神经节(DRG)神经调节作用的研究进展 神经性疼痛。因此，背根神经节似乎是下一代神经调节的一个有前途的靶点。 治疗IBS相关内脏疼痛的设备。然而，关于拓扑分布的知识缺失 以及支配结肠和直肠(结肠直肠)的功能性DRG神经元的分子图谱， 尤其是结直肠伤害性感受器。这严重阻碍了DRG的进一步发展 在治疗IBS内脏疼痛时选择性影响DRG神经元亚群的神经调节。我们的目标是 通过钙离子成像和单细胞利用我们在光电生理方面的最新技术进步 感觉神经元转录组分析研究结直肠的拓扑结构和分子特征 胸腰椎和腰椎背根神经节的伤害性感受器。 提出了三个具体目标。具体目标1将量化机械系统的拓扑分布。 对照组和延长的结直肠胸腰段和腰臀段背根神经节的伤害性感受器 过敏症。特定目标2将量化无声的结直肠伤害性感受器的拓扑分布 胸腰椎和腰椎背根神经节在对照组和延长大肠超敏反应。具体目标3将 确定胸腰椎机械和静止性伤害性感受器的分子图谱 腰椎背根神经节对照组和延长大肠超敏反应。通过建立高通量光纤 电生理学方法，我们将能够从功能上表征大量(&gt；2000)结直肠背根神经节 神经元(包括伤害性感受器)，并揭示其在胸腰段和腰椎背根神经节的拓扑分布。 结直肠伤害性感受器的单细胞转录组分析将揭示有希望的化学目标 背根神经节的神经调节。这项研究的结果将指导下一代网络的设计 以背根神经节为靶点的神经调节装置，可有效治疗慢性内脏疼痛，同时最大限度地减少 偏离目标的副作用。

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.