Initial Development of AEG-1 inactivation as a possible strategy for pain treatment

摘要 对疼痛的适当管理是一种未得到满足的医疗需求。阿片类药物仍然是一种重要的疼痛 药物，但它们在慢性非恶性疼痛中的使用导致了现在所说的 “阿片类药物泛滥”。显然迫切需要确定和验证允许发展的新目标 有效和安全的新型非阿片类止痛药。这项提议关注的是一种新的分子， 星形胶质细胞上调基因-1(AEG-1)，可能是疼痛的靶点。AEG-1，也称为胃粘附素(MTDH)， 是一种支架蛋白，通过蛋白质之间的相互作用来调节其功能。AEG-1充当脚手架 在核因子-kB信号通路中，蛋白质在多个中间信号复合体中发挥作用。 核因子-kB活化的基础分子。核因子-kB是调节促炎性反应的关键转录因子 细胞因子和AEG-1是炎症的主要调节因子。AEG-1 KO小鼠表现出明显的抑制作用 炎症和AEG-1 KO巨噬细胞对内毒素诱导的巨噬细胞有明显的抑制作用 核因子-kB活性和炎性基因表达。核因子-kB在慢性阻塞性肺疾病中的重要调节作用 炎症性疼痛。由于AEG-1调节核因子-kB，因此可以假设AEG-1可能作为一个密钥发挥作用 调节疼痛机制的分子。我们的初步研究表明，伤害行为和 炎症在完全弗氏佐剂(CFA)慢性炎性疼痛中均显著 与AEG-1 WT小鼠相比，AEG-1 KO小鼠的运动能力降低，但不影响运动活动和协调性 动物的生命。这些发现确定了AEG-1在调节慢性疼痛中的关键作用和一个潜在的靶点 用来缓解慢性疼痛。我们假设AEG-1是调节疼痛行为的有效靶点，并且 AEG-1抑制可能成为开发新的慢性疼痛镇痛剂的潜在策略。 我们将通过分析两个慢性神经病理性疼痛模型中的疼痛行为来验证我们在目标1中的假设 AEG-1KO和WT小鼠。目的2研究巨噬细胞/小胶质细胞AEG-1细胞的作用 髓系细胞特异性条件性AEG-1 KO小鼠。在目标3中，我们将评估巨噬细胞靶向的疗效。 携带AEG-1 siRNA的纳米颗粒可缓解慢性炎症性疼痛。我们的研究将确定AEG- 1作为一种调节疼痛反应的新的重要调节分子，将为下一步的研究奠定基础。 针对疼痛的RNAi策略。多项临床试验正在进行中，以测试针对各种不同基因的siRNA。 因此，这一战略在诊所管理疼痛方面具有潜在应用价值。

Summary Adequate management of pain is an unmet medical need. Opioids remain an important class of pain medications but their use in chronic, non-malignant pain has contributed to what is now referred to as the “opioid epidemic”. There is clearly an urgent need to identify and validate novel targets allowing development of novel non-opioid analgesics that are effective and safe. This proposal focuses on a new molecule, Astrocyte elevated gene-1 (AEG-1), as a possible target for pain. AEG-1, also known as metadherin (MTDH), is a scaffold protein which mediates its function by protein-protein interaction. AEG-1 functions as a scaffold protein in multiple intermediary signaling complexes in NF-kB signaling pathway, thereby functioning as a fundamental molecule in NF-kB activation. NF-kB is a key transcription factor regulating pro-inflammatory cytokines and AEG-1 is a major regulator of inflammation. AEG-1 KO mice show a profound inhibition of inflammation and AEG-1 KO macrophages show profound inhibition of lipopolysaccharide (LPS)-induced NF-kB activity and inflammatory gene expression. NF-kB plays a major regulatory role in chronic inflammatory pain. Since AEG-1 regulates NF-kB it may be hypothesized that AEG-1 might function as a key molecule regulating pain mechanisms. Our preliminary studies demonstrate that nociceptive behaviors and inflammation in both the complete Freund adjuvant (CFA) chronic inflammatory pain were significantly reduced in AEG-1 KO mice compared to AEG-1 WT mice, without affecting motor activity and coordination of the animals. These findings identify a key role of AEG-1 in regulating chronic pain and a potential target for ameliorating chronic pain. We hypothesize that AEG-1 is a valid target regulating pain behaviors and AEG-1 inhibition might be developed as a potential strategy for developing new analgesics for chronic pain. We will test our hypothesis in Aim 1 by analyzing pain behaviors in two chronic neuropathic pain models in AEG-1 KO and WT mice. Aim 2 will investigate the role of macrophage/microglia AEG-1 cells by using myeloid cell-specific conditional AEG-1 KO mouse. In Aim 3 we will evaluate efficacy of macrophage-targeted nanoparticles delivering AEG-1 siRNA to ameliorate chronic inflammatory pain. Our studies will identify AEG- 1 as a novel and crucial regulatory molecule modulating pain response and will pave the way for developing RNAi strategy for pain. Multiple clinical trials are ongoing to test siRNAs targeting diverse genes in a variety of diseases thereby establishing potential application of this strategy to manage pain in the clinics.