Department of Anesthesiology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, 110001, China.
J Neuroinflammation. 2017 Oct 23;14(1):205. doi: 10.1186/s12974-017-0977-4.
Ischemia-reperfusion (IR) affects microRNA (miR) expression and causes substantial inflammation. Multiple roles of the tumor suppressor miR-129-5p in cerebral IR have recently been reported, but its functions in the spinal cord are unclear. Here, we investigated the role of miR-129-5p after spinal cord IR, particularly in regulating high-mobility group box-1 (HMGB1) and the Toll-like receptor (TLR)-3 pathway.
Ischemia was induced via 5-min occlusion of the aortic arch. The relationship between miR-129-5p and HMGB1 was elucidated via RT-PCR, western blotting, and luciferase assays. The cellular distribution of HMGB1 was determined via double immunofluorescence. The effect of miR-129-5p on the expression of HMGB1, TLR3, and downstream cytokines was evaluated using synthetic miRs, rHMGB1, and the TLR3 agonist Poly(I:C). Blood-spinal cord barrier (BSCB) permeability was examined by measuring Evans blue (EB) dye extravasation and the water content.
The temporal miR-129-5p and HMGB1 expression profiles and luciferase assay results indicated that miR-129-5p targeted HMGB1. Compared with the Sham group, the IR group had higher HMGB1 immunoreactivity, which was primarily distributed in neurons and microglia. Intrathecal injection of the miR-129-5p mimic significantly decreased the HMGB1, TLR3, interleukin (IL)-1β and tumor necrosis factor (TNF)-α levels and the double-labeled cell count 48 h post-surgery, whereas rHMGB1 and Poly(I:C) reversed these effects. Injection of miR-129-5p mimic preserved motor function and prevented BSCB leakage based on increased Basso Mouse Scale scores and decreased EB extravasation and water content, whereas injection rHMGB1 and Poly(I:C) aggravated these injuries.
Increasing miR-129-5p levels protect against IR by ameliorating inflammation-induced neuronal and BCSB damage by inhibiting HMGB1 and TLR3-associated cytokines.
缺血再灌注（IR）会影响 microRNA（miR）的表达并引起大量炎症。肿瘤抑制因子 miR-129-5p 在大脑 IR 中的多种作用最近已被报道，但它在脊髓中的功能尚不清楚。在这里，我们研究了脊髓 IR 后 miR-129-5p 的作用，特别是在调节高迁移率族蛋白 B1（HMGB1）和 Toll 样受体（TLR）-3 途径方面。
通过主动脉弓 5 分钟闭塞诱导缺血。通过 RT-PCR、western blot 和荧光素酶测定阐明 miR-129-5p 与 HMGB1 之间的关系。通过双重免疫荧光测定 HMGB1 的细胞分布。通过合成 miR、rHMGB1 和 TLR3 激动剂 Poly(I:C) 评估 miR-129-5p 对 HMGB1、TLR3 和下游细胞因子表达的影响。通过测量 Evans 蓝（EB）染料渗出和水含量来检查血脊髓屏障（BSCB）通透性。
miR-129-5p 和 HMGB1 的时间表达谱和荧光素酶测定结果表明，miR-129-5p 靶向 HMGB1。与 Sham 组相比，IR 组的 HMGB1 免疫反应性更高，主要分布在神经元和小胶质细胞中。鞘内注射 miR-129-5p 模拟物可显著降低手术后 48 小时的 HMGB1、TLR3、白细胞介素（IL）-1β 和肿瘤坏死因子（TNF）-α 水平和双标记细胞计数，而 rHMGB1 和 Poly(I:C) 则逆转了这些作用。注射 miR-129-5p 模拟物可改善运动功能并防止 BSCB 渗漏，基于增加的 Basso 小鼠量表评分和减少的 EB 渗出和水含量，而注射 rHMGB1 和 Poly(I:C) 则加重了这些损伤。
增加 miR-129-5p 水平可通过抑制 HMGB1 和 TLR3 相关细胞因子来改善炎症引起的神经元和 BSCB 损伤，从而防止 IR。
