Wang Mengmeng, Liu Xiaoman, Wu Yu, Wang Yi, Cui Jiahui, Sun Jing, Bai Ying, Lang Ming-Fei
Department of Neurology, Affiliated Xinhua Hospital of Dalian University, Dalian, Liaoning 116021, P.R. China.
Medical College, Institute of Microanalysis, Dalian University, Dalian, Liaoning 116622, P.R. China.
Exp Ther Med. 2021 Jun;21(6):616. doi: 10.3892/etm.2021.10048. Epub 2021 Apr 14.
The protection of brain tissue against damage and the reduction of infarct size is crucial for improving patient prognosis following ischemic stroke. Therefore, the present study aimed to investigate the regulatory effect of microRNA (miR)-122 and its target gene repressor of RNA polymerase III transcription MAF1 homolog (Maf1) on the infarct area in ischemic stroke. Reverse transcription-quantitative PCR (RT-qPCR) was performed to determine miR-122 expression levels in an ischemic stroke [middle cerebral artery occlusion (MCAO)] mouse model. Nissl staining was conducted to measure the infarct area of the MCAO mouse model. Moreover, RT-qPCR was performed to investigate the relationship between the expression of Maf1 and miR-122 in the MCAO mouse model. Dual-luciferase reporter assay and miR-122 mimic or inhibitor treatment were conducted to verify that miR-122 targeted and inhibited Maf1 expression. The results suggested that miR-122 was upregulated in the brain tissue of MCAO model mice. miR-122 overexpression effectively reduced the size of the infarct area in comparison with a control and miR-122 knockdown in brain tissue resulted in the opposite effect. Moreover, Maf1 was confirmed to be a direct target of miR-122. The results of a dual-luciferase reporter assay indicated that miR-122 bound to the 3'-untranslated region of Maf1. Maf1 expression decreased after stroke model induction in comparison with that in sham animals, and Maf1 expression was negatively associated with the expression of miR-122. In addition, miR-122 knockdown increased Maf1 expression levels, whereas miR-122 overexpression decreased Maf1 expression levels in comparison with a control. In conclusion, the results suggested that miR-122 improved the outcome of acute ischemic stroke by reducing the expression of Maf1.
保护脑组织免受损伤并减小梗死面积对于改善缺血性中风患者的预后至关重要。因此，本研究旨在探讨微小RNA（miR）-122及其靶基因RNA聚合酶III转录抑制因子MAF1同源物（Maf1）对缺血性中风梗死面积的调节作用。采用逆转录定量聚合酶链反应（RT-qPCR）检测缺血性中风[大脑中动脉闭塞（MCAO）]小鼠模型中miR-122的表达水平。进行尼氏染色以测量MCAO小鼠模型的梗死面积。此外，采用RT-qPCR研究MCAO小鼠模型中Maf1与miR-122表达之间的关系。进行双荧光素酶报告基因测定以及miR-122模拟物或抑制剂处理以验证miR-122靶向并抑制Maf1表达。结果表明，MCAO模型小鼠脑组织中miR-122表达上调。与对照组相比，miR-122过表达有效减小了梗死面积，而脑组织中miR-122敲低则产生相反的效果。此外，证实Maf1是miR-122的直接靶标。双荧光素酶报告基因测定结果表明，miR-122与Maf1的3'-非翻译区结合。与假手术动物相比，中风模型诱导后Maf1表达降低，且Maf1表达与miR-122表达呈负相关。此外，与对照组相比，miR-122敲低增加了Maf1表达水平，而miR-122过表达降低了Maf1表达水平。总之，结果表明miR-122通过降低Maf1表达改善急性缺血性中风的预后。
