Department of Neurosurgery, Rizhao Central Hospital, Rizhao, 276800, Shandong, China.
Department of Orthopedics, Rizhao Central Hospital, Rizhao, 276800, Shandong, China.
Cell Biochem Biophys. 2021 Dec;79(4):791-799. doi: 10.1007/s12013-021-00992-z. Epub 2021 Jun 16.
Inflammation and oxidative stress feature prominently in the secondary spinal cord injury (SCI). The present work is targeted at deciphering miR-145-5p's role and underlying mechanism in SCI. We randomly divided Sprague-Dawley rats into SCI group and control group. Microglial BV2 cells were separated into control group and lipopolysaccharide (LPS) treatment group. Enzyme-linked immunosorbent assay was carried out for determining the concentrations of interleukin-6, interleukin-1β, and tumor necrosis factor-α (TNF-α). The expressions of malondialdehyde, glutathione peroxidase, superoxide dismutase, and reactive oxygen species were also detected. TNF-α, miR-145-5p, and Nurr1 expressions were examined by western blot and quantitative real-time polymerase chain reaction. Western blotting and dual-luciferase reporter gene assay were conducted to examine the regulating impact that miR-145-5p had on Nurr1 and TNF-α. MiR-145-5p was remarkably upregulated in the SCI rat model's spinal cord tissues and BV2 cells treated with LPS, and Nurr1 expression was dramatically lowered. Furthermore, miR-145-5p inhibition markedly repressed inflammatory and oxidative stress responses. Moreover, it was proved that Nurr1 was a direct miR-145-5p target. The inhibition of miR-145-5p helped promote Nurr1 expression to block TNF-α signaling. MiR-145-5p inhibition mitigates inflammation and oxidative stress via targeting Nurr1 to regulate TNF-α signaling, which ameliorates SCI.
炎症和氧化应激在继发性脊髓损伤 (SCI) 中表现突出。本工作旨在阐明 miR-145-5p 在 SCI 中的作用及其潜在机制。我们将 Sprague-Dawley 大鼠随机分为 SCI 组和对照组。分离小胶质细胞 BV2 细胞分为对照组和脂多糖 (LPS) 处理组。采用酶联免疫吸附试验测定白细胞介素-6、白细胞介素-1β 和肿瘤坏死因子-α (TNF-α) 的浓度。还检测了丙二醛、谷胱甘肽过氧化物酶、超氧化物歧化酶和活性氧的表达。通过 Western blot 和定量实时聚合酶链反应检测 TNF-α、miR-145-5p 和 Nurr1 的表达。Western blot 和双荧光素酶报告基因检测用于检测 miR-145-5p 对 Nurr1 和 TNF-α 的调节作用。在 SCI 大鼠模型的脊髓组织和 LPS 处理的 BV2 细胞中，miR-145-5p 表达显著上调，Nurr1 表达显著下调。此外，miR-145-5p 抑制显著抑制炎症和氧化应激反应。此外，证明 Nurr1 是 miR-145-5p 的直接靶标。miR-145-5p 抑制通过靶向 Nurr1 阻断 TNF-α 信号通路来促进 Nurr1 表达。miR-145-5p 抑制通过靶向 Nurr1 调节 TNF-α 信号通路减轻炎症和氧化应激，从而改善 SCI。
