Department of Spine Surgery, Jining No. 1 People's Hospital, Jining, China.
Eur Rev Med Pharmacol Sci. 2019 Apr;23(7):2719-2726. doi: 10.26355/eurrev_201904_17543.
This study aims to elucidate the potential role of microRNA-448 in the recovery of spinal cord injury (SCI), and to explore the underlying mechanism.
MicroRNA-448 expression was determined by microarray and the established SCI model in mice. The target gene of microRNA-448 was predicted using bioinformatics. The functional binding of the target gene to microRNA-448 was verified by Dual-Luciferase reporter gene assay. The regulatory effects of microRNA-448 and Bcl-2 on apoptosis, motor neuron number and grip strength were evaluated. After injection of microRNA-448 mimics, microRNA-448 inhibitor or Bcl-2 siRNA in mice, expression levels of PI3K/AKT and Caspase3 were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot.
Grip strength of SCI mice significantly decreased compared with mice in the sham group. The microRNA-448 expression gradually increased with the progression of SCI, whereas the Bcl-2 expression decreased. Dual-Luciferase reporter gene assay showed the binding condition between microRNA-448 and Bcl-2. Furthermore, the Bcl-2 expression was negatively regulated by microRNA-448 at both mRNA and protein levels. The injection of microRNA-448 inhibitor into the injured spinal cord of SCI mice significantly upregulated the expressions of p-PI3K, p-AKT and Caspase3, as well as motor neuron regeneration and grip strength. However, the promotive effects of microRNA-448 inhibitor were blocked by Bcl-2 siRNA transfection.
MicroRNA-448 is upregulated after SCI, which may be involved in the regenerative process of spinal motor nerves by regulating PI3K/AKT/Bcl-2 axis.
本研究旨在阐明 microRNA-448 在脊髓损伤 (SCI) 恢复中的潜在作用，并探讨其潜在机制。
通过微阵列和建立的 SCI 模型小鼠确定 microRNA-448 的表达。使用生物信息学预测 microRNA-448 的靶基因。通过双荧光素酶报告基因检测验证靶基因与 microRNA-448 的功能结合。评估 microRNA-448 和 Bcl-2 对细胞凋亡、运动神经元数量和握力的调节作用。在 SCI 小鼠中注射 microRNA-448 模拟物、microRNA-448 抑制剂或 Bcl-2 siRNA 后，通过定量实时聚合酶链反应 (qRT-PCR) 和 Western blot 检测 PI3K/AKT 和 Caspase3 的表达水平。
与假手术组小鼠相比，SCI 小鼠的握力明显下降。microRNA-448 的表达随着 SCI 的进展逐渐增加，而 Bcl-2 的表达则下降。双荧光素酶报告基因检测显示 microRNA-448 与 Bcl-2 的结合情况。此外，microRNA-448 在 mRNA 和蛋白水平上均负调控 Bcl-2 的表达。将 microRNA-448 抑制剂注入 SCI 小鼠损伤的脊髓中，可显著上调 p-PI3K、p-AKT 和 Caspase3 的表达以及运动神经元再生和握力。然而，Bcl-2 siRNA 转染阻断了 microRNA-448 抑制剂的促进作用。
SCI 后 microRNA-448 表达上调，可能通过调节 PI3K/AKT/Bcl-2 轴参与脊髓运动神经的再生过程。
