miR-155通过激活缺血性脑组织中的自噬参与神经损伤

miR-155 participate in nerve damage through activating autophagy in ischemic cerebral tissues

目的探讨自噬与脑缺血之间的关系,以及miR-155在缺血脑组织中对自噬的影响。方法线栓法制备大脑中动脉闭塞(MCAO)模型,行为学测试包括神经功能缺损评分和转角试验测评,Western blotting测定LC3B和p62蛋白表达,RT-PCR测定ULK1和Beclin基因水平。结果与MCAO组相比,过表达miR-155组自噬相关蛋白LC3 II和ULK1、Beclin 1基因显著增高,神经功能缺损评分升高;miR-155敲除小鼠中自噬蛋白LC3 II和ULK1、Beclin 1基因降低;而添加自噬抑制剂抑制miR-155诱导缺血自噬后,神经功能缺损评分降低,自噬相关蛋白LC3 II和ULK1、Beclin 1基因均下降。结论证实miR-155激活了缺血诱导的自噬,而应用自噬抑制剂可以阻滞miR-155的有害作用。在缺血性脑组织中沉默miR-155不仅可以抑制自噬,还可以减轻神经功能缺损评分,改善自噬导致的脑缺血损伤。

Objective To investigate the relation of autophagy and cerebral ischemic,and the effects of miR-155 on autophagy in ischemic cerebral tissues.Methods The model of permanent right middle cerebral artery occlusion(MCAO),the behavior tests including neurological deficit score and corner test.The expression of LC3 B and p62 protein were determined by Western blotting,ULK1 and Beclin gene were determined by RTPCR.Results Compared with MCAO group,the protein level of LC3 II and the gene level of ULK1,Beclin 1 were significantly increased in miR-155 overexpression group.Compared with MCAO group,the protein level of LC3 II and the gene level of ULK1,Beclin 1 were significantly decreased in miR-155 KO group.Compared with MCAO group,LC3 II and ULK1,Beclin 1 levels were all significantly downregulated in fed with autophagy inhibitor,and significantly lower neurological scores.Conclusions miR-155 activates autophagy in cerebral ischemic tissues,treated with autophagy inhibitor can inhibit the harmful effects of miR-155.Silence miR-155 in the ischemic cerebral tissues can inhibit autophagy,reduce neurological deficit scores,and restore neural injury of autophagy induced in ischemic cerebral tissues.