Regulation of Schwann Cell Mitochondria Homeostasis in Painful Peripheral Neuropathy

项目总结 周围神经疾病有不同的病因，可出现在创伤性、代谢性和 化疗引发的事件。神经性疼痛是周围神经病的主要症状，它是 以自发性疼痛、灼热和感觉异常为特征。通常，它与毁灭性的损失有关 生活质量。目前，治疗是有限的，并给副作用和成瘾的患者带来负担。识别 疼痛治疗的新战略解决了大量未得到满足的医疗需求。生物力学的机理研究进展 痛性周围神经病(PPN)主要集中在感觉神经元，然而，周围神经胶质细胞，雪旺 细胞(SCs)是调节疼痛的感觉神经元的功能单位的重要组成部分 各州。然而，SC对PPN的贡献机制在很大程度上是未知的。线粒体失调 已被确认为与PPN相关的机制。不过，有两项研究表明，基因 一种关键的线粒体蛋白缺失会导致进行性脱髓鞘神经病，目前还没有研究 将SC修复受体信号通路(可用于治疗)与线粒体联系起来 干细胞的异质性和/或内稳态，与神经病理性疼痛有关。我们发现了低密度的 脂蛋白受体相关蛋白(LRP1)作为SC损伤后修复的关键受体。的一个重要性质 LRP1是其调节脂质代谢和葡萄糖动态平衡的能力，从而控制细胞 生物能量学。我们认为LRP1直接调节SCs中线粒体的动力学和功能，以优化 周围神经中的生物能量平衡。我们之前的工作是研究SC LRP1在神经炎症和 疼痛，以及令人兴奋的新的初步数据显示LRP1调节SC细胞质中的线粒体数量 对有髓纤维的研究，为我们检验这一假说提供了独特的条件。在目标1中，我们将研究对SC的监管 线粒体异质性和生物能量学。我们建议对整个神经裂解液和分离的神经进行分析 来自转基因小鼠的原代干细胞培养(MSC)，其中LRP1有条件地从干细胞中缺失(scLRP1-/-)。 我们计划用一种创新的LRP1激活剂来挑战MSC的新陈代谢，目前正在进行第二阶段的临床试验。我们 还将测试LRP1调节的SC线粒体如何通过化疗药物治疗来应对压力 已知可诱发PPN。在目标2中，我们将使用无偏倚的蛋白质组学来鉴定线粒体蛋白质组 分别从scLRP1-/-和scLRP1/分离的神经病理性和幼稚干细胞中筛选。然后，我们将在 SCS中LRP1的条件性缺失如何触发PPN和应用全局非靶向的蛋白质蓝图 代谢组学，以确定关键代谢物的变化。这些研究将揭示关于 与PPN相关的SCs的线粒体动力学、含量和代谢。

PROJECT SUMMARY Peripheral neuropathies have heterogeneous etiologies and can emerge from traumatic, metabolic and chemotherapy induced events. Neuropathic pain is a major symptom of peripheral neuropathies, which is characterized by spontaneous pain, burning and paresthesia. Often it is associated with devastating losses of quality of life. Currently, treatments are limited and burden patients with side effects and addiction. Identifying novel strategies for pain treatment addresses a substantial unmet medical need. Research in mechanisms of painful peripheral neuropathy (PPN) has largely focused on sensory neurons, however, peripheral glia, Schwann cells (SCs), emerge as an essential component of the functional unit with sensory neurons that regulate pain states. Yet, mechanisms underlying SC contributions to PPN are largely unknown. Mitochondria dysregulation in neurons has been identified as a mechanism associated with PPN. Although, two studies show that genetic deletion of a key mitochondrial protein elicits a progressive demyelinating neuropathy, there are no studies linking a SC repair receptor signaling pathway (which could be targeted therapeutically) with mitochondria heterogeneities and/or homeostasis in SCs, relevant to neuropathic pain. We identified the low-density lipoprotein receptor related protein (LRP1) as a key SC repair receptor after injury. An important property of LRP1 is its ability to regulate lipid metabolism and glucose homeostasis, and therefore, control cellular bioenergetics. We propose that LRP1 directly regulates mitochondrial dynamics and function in SCs to optimize bioenergetic homeostasis in peripheral nerves. Our prior work investigating SC LRP1 in neuroinflammation and pain, and exciting new preliminary data showing LRP1 regulation of mitochondria numbers in the SC cytoplasm of myelinated fibers, uniquely positions us to test this hypothesis. In Aim 1, we will examine regulation of SC mitochondrial heterogeneities and bioenergetics. We propose analyses in whole nerve lysates and isolated primary SC cultures (mSC) from transgenic mice in which LRP1 is conditionally deleted from SCs (scLRP1-/-). We plan to challenge mSC metabolism with an innovative LRP1 activator, currently in phase II clinical trials. We also will test how LRP1 regulated SC mitochondria respond to stress by treatment with a chemotherapy agent known to induce PPN. In Aim 2, we will identify the mitochondrial proteome by using an unbiased proteomics screen from neuropathic and naive SCs isolated from scLRP1-/- and scLRP1+/+, respectively. We then build on the protein blueprint of how conditional deletion of LRP1 in SCs triggers PPN and apply global untargeted metabolomics to identify key metabolite changes. These studies will reveal entirely new information about mitochondria dynamics, content, and metabolism of SCs related to PPN.