microRNA regulation of NMNAT-mediated Neuroprotection against Peripheral Neuropathy and Chronic Pain

MicroRNA对NMNAT介导的神经保护作用的调节 慢性疼痛 项目总结 周围神经病和神经病痛可由多种遗传和环境因素引起 因素以及治疗性或娱乐性药物的使用。特别是，化疗诱导的外周 神经病(CIPN)是标准化疗方案的主要剂量限制性神经毒性副作用。完毕 68%的癌症患者在化疗后出现神经病变症状，这导致 患有慢性疼痛并不得不求助于阿片类药物使用的人口中，有相当比例的人。目前 目前尚无有效的治疗方法，这主要是由于对其体内机制缺乏了解。 CIPN及相关的周围神经病。最近，我们优化了一种周围神经病的模型 果蝇幼虫概括了化疗的显著行为和神经元形态方面- 诱发感觉功能障碍。我们利用该模型的初步工作揭示了一种新的机制 潜在的周围神经病变，并确定了一种神经保护蛋白NMNAT，具有潜在的 减轻神经病理性疼痛。我们研究的最终目的是揭示内生机制 并确定神经保护机制和潜在靶点 促进针对CIPN和相关神经病理性疼痛的新治疗药物的开发。 我们之前在神经元维护和保护方面的工作已经确定了NMNAT(烟酰胺 NAD+合成途径中的最后一种酶--单核苷酸腺苷转移酶)，作为NAD+合成途径中的必需基因 维持神经元结构和功能的完整性。来自我们实验室和其他实验室的广泛的机械研究 发现果蝇和哺乳动物中的NMNAT蛋白是最强大和最多功能的蛋白质之一 神经保护因子，以及NMNAT表达水平与神经元自身 保护能力。令人兴奋的是，从化合物筛选中，几种天然化合物被鉴定为 上调NMNAT转录，我们收集了有趣的初步结果，表明 NMNAT的表达受microRNAs的调控。我们假设NMNAT RNA表达的调节 通过天然化合物和microRNAs在转录、前mRNA剪接和mRNA稳定性等步骤中 允许在NMNAT介导的NAD+代谢和神经元弹性之间快速和动态地转换，以及 保护感觉神经元免受周围神经病的侵袭。在本应用程序中，我们概述了 实验：(1)识别调控伤害性超敏反应的microRNAs；(2)识别和表征 天然化合物调节NMNAT表达的分子药理作用；(3)调节NMNAT 转录调控以增强对周围神经病的神经保护。在网络中 对化疗引起的周围神经病变做出反应的汇聚通路，了解 NMNAT在NAD+代谢中的调节和增强神经元动态平衡将有助于发现 周围神经病和神经病理性疼痛的神经保护策略。

MicroRNA Regulation of NMNAT-Mediated Neuroprotection Against Peripheral Neuropathy and Chronic Pain PROJECT SUMMARY Peripheral neuropathy and neuropathy pain can be caused by a myriad of genetic and environment factors as well as therapeutic or recreational drug use. In particular, chemotherapy-induced peripheral neuropathy (CIPN) is the major dose-limiting neurotoxic side effect of standard chemotherapy regiments. Over 68% of cancer patients experience neuropathic symptoms after chemotherapy, and that contributes to a significant percent of the population that suffer from chronic pain and have to resort to opioid use. Currently there are no effective treatments available, largely due to a lack of understanding of the in vivo mechanisms of CIPN and related peripheral neuropathy. Recently, we have optimized a model of peripheral neuropathy using Drosophila larvae that recapitulates salient behavior and neuronal morphological aspects of chemotherapy- induced sensory dysfunction. Our preliminary work using this model has uncovered a new mechanism underlying peripheral neuropathy, and identified a neuroprotective protein NMNAT with promising potential for mitigating neuropathic pain. The ultimate goal of our research is to uncover the endogenous mechanisms underlying peripheral neuropathy and to identify neuroprotective mechanisms and potential targets that facilitate the development of new therapeutic agents against CIPN and related neuropathic pain. Our previous work on neuronal maintenance and protection has identified NMNAT (nicotinamide mononucleotide adenylyl transferase), the last enzyme in NAD+ synthesis pathway, as an essential gene that maintains neuronal structural and functional integrity. Extensive mechanistic studies from our lab and others have found NMNAT proteins in Drosophila and mammals to be among the most robust and versatile neuroprotective factors, and a positive correlation between NMNAT expression levels and the neuronal self- protective capacity. Excitingly, from a compound screen, several natural compounds were identified to upregulate NMNAT transcription, and we have collected intriguing preliminary results suggesting that the expression of NMNAT is regulated by microRNAs. We hypothesize that regulation of NMNAT RNA expression by natural compounds and microRNAs at the steps of transcription, pre-mRNA splicing, and mRNA stability allows rapid and dynamic shifting between NMNAT mediated NAD+ metabolism and neuronal resilience, and confers protection in sensory neurons against peripheral neuropathy. In this application we outline experiments to (1) identify microRNAs that regulate nociceptive hypersensitivity, (2) identify and characterize the molecular pharmacology of natural compounds in regulating NMNAT expression, and (3) modulate NMNAT transcriptional regulation to enhance neuroprotection against peripheral neuropathy. Within the network of convergent pathways responding to chemotherapy induced peripheral neuropathy, understanding the regulation of NMNAT in both NAD+-metabolism and enhancing neuronal homeostasis will facilitate discovery of neuroprotective strategies in peripheral neuropathy and neuropathic pain.