Department of Orthopedics, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Department of Orthopedics, Nanjing First Hospital, Nanjing Medical University, Nanjing, China.
Brain Behav Immun. 2020 Jul;87:531-542. doi: 10.1016/j.bbi.2020.01.025. Epub 2020 Jan 31.
Spinal cord injury (SCI) is a destructive polyneuropathy that can result in loss of sensorimotor function and sphincter dysfunction, and even death in critical situations. MicroRNAs (miRs) are a series of non-coding RNA molecules that are involved in transcriptional regulation. Previous studies have demonstrated that modulation of multiple miRs is involved in neurological recovery after SCI. However, the functions of miR-340-5p in SCI remain uncertain. Therefore, we probed the therapeutic effect and mechanism of miR-340-5p in microglia in vitro and in vivo in SCI rats. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were employed to examine the alterations in miR-340-5p and P38 levels in SCI rats. miR-340-5p targets in microglia were ascertained using luciferase reporter assays, immunofluorescence analyses, and western blotting. We also established an SCI model and administered miR-340-5p. The effects of miR-340-5p on the amelioration of inflammation, oxidative stress, and apoptosis following SCI were assessed using immunofluorescence, immunohistochemistry, and histological analyses. Finally, locomotor function recovery was determined using the Basso, Beattie, Bresnahan rating scale. In our study, the expression profiles and luciferase assay results clarified that P38 was a target of miR-340-5p, which was associated with activation of the P38-MAPK signaling pathway. Elevation of miR-340-5p decreased P38 expression, subsequently inhibiting the inflammatory reaction. SCI-induced secondary neuroinflammation was relieved under miR-340-5p treatment. Moreover, by controlling neuroinflammation, the increased levels of miR-340-5p might counter oxidative stress and reduce the degree of apoptosis. We also observed decreasing gliosis and glial scar formation and increasing neurotrophin expression at the chronic stage of SCI. Together, these potential effects of miR-340-5p treatment ultimately improved locomotor function recovery in SCI rats.
脊髓损伤 (SCI) 是一种破坏性的多神经病，可导致感觉运动功能丧失和括约肌功能障碍，在危急情况下甚至死亡。微小 RNA（miRs）是一系列参与转录调控的非编码 RNA 分子。先前的研究表明，SCI 后多种 miR 的调节与神经功能恢复有关。然而，miR-340-5p 在 SCI 中的功能仍不确定。因此，我们在 SCI 大鼠体内和体外研究了 miR-340-5p 对小胶质细胞的治疗作用和机制。逆转录定量聚合酶链反应（RT-qPCR）和蛋白质印迹法用于检测 SCI 大鼠中 miR-340-5p 和 P38 水平的变化。使用荧光素酶报告基因分析、免疫荧光分析和蛋白质印迹法确定 miR-340-5p 在小胶质细胞中的靶标。我们还建立了 SCI 模型并给予 miR-340-5p。通过免疫荧光、免疫组织化学和组织学分析评估 miR-340-5p 对 SCI 后炎症、氧化应激和细胞凋亡的改善作用。最后，使用 Basso、Beattie、Bresnahan 评分量表评估运动功能恢复情况。在我们的研究中，表达谱和荧光素酶测定结果表明 P38 是 miR-340-5p 的靶标，与 P38-MAPK 信号通路的激活有关。miR-340-5p 的升高降低了 P38 的表达，从而抑制了炎症反应。在 miR-340-5p 治疗下，SCI 诱导的继发性神经炎症得到缓解。此外，通过控制神经炎症，miR-340-5p 的水平升高可能会对抗氧化应激并降低细胞凋亡程度。我们还观察到慢性 SCI 时神经胶质增生和胶质瘢痕形成减少，神经营养因子表达增加。综上所述，miR-340-5p 治疗的这些潜在作用最终改善了 SCI 大鼠的运动功能恢复。
