Background and aim

Ischemic stroke is one of the main causes of death worldwide and permanent global disability. On the basis of existing literature data, the study was carried out in an effort to explore how miR-140-5p affects ischemic stroke and whether the mechanism relates to toll-like receptor-4 (TLR4) and nuclear factor-kappa B (NF-κB).

Methods

Firstly, middle cerebral artery occlusion (MCAO) was performed to establish mouse models of ischemic stroke in vivo, while primary neurons were exposed to oxygen-glucose deprivation (OGD) to set up an ischemic stroke model in vitro. RT-qPCR was then applied to detect the miR-140-5p expression patterns, whereas Western blot was adopted to detect the expression patterns of TLR4, NF-κB, and apoptosis-related factors. In addition, based gain-function of experiments using miR-140-5p mimic and TLR4 over-expression plasmid, neurological function score, TTC staining, TUNEL staining, as well as flow cytometry were carried out to evaluate the effects of miR-140-5p and TLR4 on MCAO mice and OGD neurons. Moreover, dual-luciferase reporter assay was applied to validate the targeting relationship between miR-140-5p and TLR4.

Results

Initial findings revealed that miR-140-5p was poorly-expressed, while TLR4 was highly-expressed in ischemic stroke. It was verified that miR-140-5p targeted TLR4 and downregulated its expression. MiR-140-5p over-expression was observed to inhibit the apoptosis of neurons under OGD exposure and restrain the progression of ischemic stroke, while TLR4 over-expression promoted the apoptosis and disease progression. Besides, miR-140-5p over-expression led to a decrease in NF-κB protein levels, which were increased by TLR4 over-expression.

Conclusion

In conclusion, our data indicates that miR-140-5p over-expression may be instrumental for the therapeutic targeting of ischemic stroke by alleviating neuron injury with the involvement of the TLR4/NF-κB axis.

中文翻译：

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microRNA-140-5p 通过调节 TLR4/NF-κB 轴对小鼠缺血性中风的神经保护作用

 背景和目的

缺血性中风是全球死亡和全球永久性残疾的主要原因之一。本研究在现有文献数据的基础上，探讨miR-140-5p如何影响缺血性脑卒中，以及其机制是否与Toll样受体4（TLR4）和核因子κB（NF）有关。 -κB）。

 方法

首先采用大脑中动脉闭塞（MCAO）在体内建立小鼠缺血性脑卒中模型，同时对原代神经元进行氧糖剥夺（OGD）在体外建立缺血性脑卒中模型。采用RT-qPCR检测miR-140-5p的表达模式，采用Western blot检测TLR4、NF-κB及凋亡相关因子的表达模式。此外，使用miR-140-5p模拟物和TLR4过表达质粒进行基于增益功能的实验、神经功能评分、TTC染色、TUNEL染色以及流式细胞术来评估miR-140-5p的效果。 MCAO 小鼠和 OGD 神经元上的 5p 和 TLR4。此外，应用双荧光素酶报告基因测定来验证miR-140-5p和TLR4之间的靶向关系。

 结果

初步研究结果显示，miR-140-5p 在缺血性中风中表达较差，而 TLR4 高表达。证实miR-140-5p靶向TLR4并下调其表达。观察到 MiR-140-5p 过表达可抑制 OGD 暴露下神经元的凋亡并抑制缺血性中风的进展，而 TLR4 过表达则促进细胞凋亡和疾病进展。此外，miR-140-5p过表达导致NF-κB蛋白水平降低，而TLR4过表达则增加NF-κB蛋白水平。

 结论

总之，我们的数据表明，miR-140-5p 过表达可能有助于通过 TLR4/NF-κB 轴的参与减轻神经元损伤，从而有助于缺血性中风的治疗靶向。