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

MicroRNA对NMNAT介导的周围神经保护作用的调控及机制研究 慢性疼痛 项目摘要 周围神经病变和神经病变疼痛可由无数的遗传和环境引起 因素以及治疗性或娱乐性药物的使用。特别是，化疗诱导的外周血淋巴细胞 神经病变（CIPN）是标准化疗方案的主要剂量限制性神经毒性副作用。超过 68%的癌症患者在化疗后会出现神经病变症状，这导致了 患有慢性疼痛并不得不诉诸阿片类药物使用的人口的显着百分比。目前 目前还没有有效的治疗方法，这主要是由于缺乏对体内机制的了解， CIPN和相关周围神经病变。最近，我们优化了周围神经病变模型， 果蝇幼虫重现化疗的显著行为和神经元形态学方面- 引起感觉功能障碍。我们使用这个模型的初步工作揭示了一个新的机制 潜在的周围神经病变，并确定了神经保护蛋白NMNAT有希望的潜力， 减轻神经性疼痛。我们研究的最终目的是揭示内源性机制 潜在的周围神经病变，并确定神经保护机制和潜在的目标， 促进针对CIPN和相关神经性疼痛的新治疗剂的开发。 我们以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个酶--腺苷单核苷酸腺苷酰转移酶）作为一种必需基因， 保持神经元结构和功能的完整性。我们实验室和其他机构的广泛机制研究 已经在果蝇和哺乳动物中发现NMNAT蛋白是最强大和通用的蛋白质之一 神经保护因子，以及NMNAT表达水平与神经元自身免疫功能之间的正相关性。 保护能力。令人兴奋的是，从化合物筛选中，发现了几种天然化合物， 上调NMNAT转录，我们已经收集了有趣的初步结果，表明 NMNAT的表达受microRNA调控。我们假设NMNAT RNA表达的调节 在转录、前mRNA剪接和mRNA稳定性的步骤中， 允许NMNAT介导的NAD+代谢和神经元弹性之间的快速和动态转换， 保护感觉神经元免受周围神经病变。在本申请中，我们概述了 实验以（1）鉴定调节伤害性超敏反应的microRNA，（2）鉴定和表征 天然化合物调节NMNAT表达的分子药理学，以及（3）调节NMNAT 转录调节以增强针对周围神经病变的神经保护。的网络内 对化疗引起的周围神经病变的会聚通路，了解 NMNAT在NAD+代谢和增强神经元稳态中的调节将有助于发现 在周围神经病变和神经性疼痛中的神经保护策略。

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.