BACKGROUND Recent studies have elucidated the instrumental role of microRNAs (miRNAs) in neuropathic pain (NP) progression. As one member of miRNAs, miR-130a-3p has been proved as a mediator in inflammation and neuronal maturation. The present study attempted to elucidate what effect miR-130a-3p exerts on NP. MATERIALS AND METHODS The miR-130a-3p expression in the spinal cord tissues of rat with spinal cord compression injury (SCI) and LPS-induced BV2 microglia was determined with RT-PCR, which was further applied to analyze the clinical relevance between miR-130a-3p and neuropathic pain. Besides, the expression of IGF-1, IL-1β, IL-6, and TNF-α in the spinal cord tissues of rats was measured using RT-PCR and ELISA after intrathecal injection of miR-130a-3p inhibitors and tail vein injection of IGF-1 low-expression lentivirus (Lv-shIGF-1). Further, neuronal apoptosis (labeled by Caspase3) and microglial activation (labeled by Iba1) were examined by immunohistochemistry (IHC), and the levels of IGF-1, IGF-1R, NF-κB were determined by western blot. Additionally, bioinformatic was employed to analyze the potential target genes of miR-130a-3p. Furthermore, the dual luciferase activity assay and RNA immunoprecipitation assay were conducted to further substantiate whether miR-130a-3p targets IGF-1. RESULTS In comparison with the sham group, the miR-130a-3p expression was remarkably up-regulated in the spinal cord lesions of SCI rats. The ELISA results showed that inhibiting the miR-130a-3p significantly reduced NP symptoms of SCI rats, mitigated neuronal apoptosis, microglial activation, repressed NF-κB phosphorylation and the IL-1β, IL-6 and TNF-α expressions in SCI rats. Contrarily, downregulation of miR-130a-3p increased IGF-1 and IGF-1R expression. What's more, we observed the same effects in BV2 microglia. In addition, the bioinformatics analysis showed that miR-130-3p targeted at the 3'-untranslated region of IGF-1 and inhibiting its expression. However, abolishing IGF-1 not only promoted the inflammatory responses in the SCI lesions, but also aggravated NP of SCI rats, while those effects were attenuated by the downregulation of miR-130a-3p. CONCLUSION The inhibition of miR-130a-3p expression up-regulates the IGF-1/IGF-1R signaling pathway, thus reducing neuropathic pain caused by spinal cord injury.

中文翻译：

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敲低 miR-130a-3p 通过激活 IGF-1/IGF-1R 通路减轻脊髓损伤诱导的神经性疼痛

背景最近的研究阐明了微RNA (miRNA) 在神经性疼痛(NP) 进展中的工具作用。作为 miRNA 的一个成员，miR-130a-3p 已被证明是炎症和神经元成熟的介质。本研究试图阐明 miR-130a-3p 对 NP 的影响。材料与方法RT-PCR检测脊髓压迫性损伤（SCI）大鼠和LPS诱导的BV2小胶质细胞脊髓组织中miR-130a-3p的表达，进一步分析miR-130a-3p与LPS诱导的BV2小胶质细胞的临床相关性。 130a-3p 和神经性疼痛。此外，鞘内注射miR-130a-3p抑制剂和尾静脉注射后，采用RT-PCR和ELISA检测大鼠脊髓组织中IGF-1、IL-1β、IL-6和TNF-α的表达IGF-1 低表达慢病毒 (Lv-shIGF-1)。更多，通过免疫组织化学（IHC）检查神经元凋亡（由 Caspase3 标记）和小胶质细胞活化（由 Iba1 标记），并通过蛋白质印迹测定 IGF-1、IGF-1R、NF-κB 的水平。此外，生物信息学被用来分析 miR-130a-3p 的潜在靶基因。此外，进行双荧光素酶活性测定和 RNA 免疫沉淀测定以进一步证实 miR-130a-3p 是否靶向 IGF-1。结果与假手术组相比，SCI大鼠脊髓病变中miR-130a-3p表达显着上调。ELISA结果显示，抑制miR-130a-3p可显着减轻SCI大鼠的NP症状，减轻神经元凋亡、小胶质细胞活化，抑制SCI大鼠的NF-κB磷酸化和IL-1β、IL-6和TNF-α的表达。相反，miR-130a-3p 的下调增加了 IGF-1 和 IGF-1R 的表达。更重要的是，我们在 BV2 小胶质细胞中观察到了相同的效果。此外，生物信息学分析表明，miR-130-3p 靶向 IGF-1 的 3'-非翻译区并抑制其表达。然而，消除 IGF-1 不仅促进了 SCI 病变中的炎症反应，而且加剧了 SCI 大鼠的 NP，而这些影响通过 miR-130a-3p 的下调而减弱。结论抑制miR-130a-3p表达上调IGF-1/IGF-1R信号通路，从而减轻脊髓损伤引起的神经性疼痛。- IGF-1 的非翻译区并抑制其表达。然而，消除 IGF-1 不仅促进了 SCI 病变中的炎症反应，而且加剧了 SCI 大鼠的 NP，而这些影响通过 miR-130a-3p 的下调而减弱。结论抑制miR-130a-3p表达上调IGF-1/IGF-1R信号通路，从而减轻脊髓损伤引起的神经性疼痛。- IGF-1 的非翻译区并抑制其表达。然而，消除 IGF-1 不仅促进了 SCI 病变中的炎症反应，而且加剧了 SCI 大鼠的 NP，而这些影响通过 miR-130a-3p 的下调而减弱。结论抑制miR-130a-3p表达上调IGF-1/IGF-1R信号通路，从而减轻脊髓损伤引起的神经性疼痛。