中国神经再生研究(英文版)

中国神经再生研究(英文版) ›› 2016, Vol. 11 ›› Issue (2): 262-269.doi: 10.4103/1673-5374.177734

• 原著:脑损伤修复保护与再生 • 上一篇    下一篇

let-7a基因敲除能保护脑缺血再灌注损伤？

  

  • 收稿日期:2015-12-22 出版日期:2016-02-15 发布日期:2016-02-15
  • 基金资助:

    国家自然科学基金(81460193)

Let-7a gene knockdown protects against cerebral ischemia/reperfusion injury

Zhong-kun Wang 1, Fang-fang Liu 2, Yu Wang 3, Xin-mei Jiang 1, Xue-fan Yu 1   

  1. 1 Department of Neurology, First Hospital, Jilin University, Changchun, Jilin Province, China
    2 Department of Neurology, Jilin Central Hospital, Jilin, Jilin Province, China
    3 Department of Hepatopancreatobiliary Surgery, the Second Hospital of Jilin University, Changchun, Jilin Province, China
  • Received:2015-12-22 Online:2016-02-15 Published:2016-02-15
  • Contact: Xin-mei Jiang, M.D., Ph.D. or Xue-fan Yu, M.D., Ph.D., jiangxinmei126@126.com or yuxuefan163@163.com.
  • Supported by:

    This study was supported by the National Natural Science Foundation of China, No. 81460193.

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摘要：

let-7是最早被发现在物种间高度保守且广泛性表达的 miRNAs，在脑缺血再灌注后脑组织中表达显著上调，但尚无相关报道揭示其对脑缺血再灌注后神经损伤的影响。我们假设let-7a基因敲除可保护脑缺血再灌注损伤，实验建立脑缺血再灌注大鼠模型，通过qRT-PCR检测发现，脑缺血再灌注后12 h大鼠脑组织内let-7a表达上调，24 h时达到顶峰，72 h时仍高于正常大鼠。沉默let-7a基因表达可抑制脑缺血再灌注大鼠脑组织内小胶质细胞的激活和炎症因子的释放，并减轻神经细胞的凋亡，缩小大鼠脑梗死体积。通过western blot、luciferase assay等研究方法进一步发现，重要抗炎及抗凋亡因子丝裂原活化蛋白激酶磷酸酶1(mitogen-activated protein kinase phosphatase-1, MKP1)是let-7a的直接作用靶点，let-7a可通过下调MKP1增强脑组织内磷酸化p38 MAPK和JNK的表达，说明let-7a基因敲除可通过上调MKP1表达来抑制p38MAPK和JNK信号通路的激活，减轻脑缺血再灌注后的炎症反应和细胞凋亡起到神经保护作用。

关键词: 神经再生, 脑损伤, 脑缺血再灌注, let-7, mitogen-activated protein kinase phosphatase-1, 凋亡, 炎症, 小胶质细胞, mitogen-activated protein kinase, 神经元, c-Jun N-terminal kinase, 基因敲除, 国家自然科学基金

Abstract:

The microRNA (miRNA) let-7 was one of the first miRNAs to be discovered, and is highly conserved and widely expressed among species. let-7 expression increases in brain tissue after cerebral ischemia/reperfusion injury; however, no studies have reported let-7 effects on nerve injury after cerebral ischemia/reperfusion injury. To investigate the effects of let-7 gene knockdown on cerebral ischemia/reperfusion injury, we established a rat model of cerebral ischemia/reperfusion injury. Quantitative reverse transcription-polymerase chain reaction demonstrated that 12 hours after cerebral ischemia/reperfusion injury, let-7 expression was up-regulated, peaked at 24 hours, and was still higher than that in control rats after 72 hours. Let-7 gene knockdown in rats suppressed microglial activation and inflammatory factor release, reduced neuronal apoptosis and infarct volume in brain tissue after cerebral ischemia/reperfusion injury. Western blot assays and luciferase assays revealed that mitogen-activated protein kinase phosphatase-1 (MKP1) is a direct target of let-7. Let-7 enhanced phosphorylated p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) expression by down-regulating MKP1. These findings suggest that knockdown of let-7 inhibited the activation of p38 MAPK and JNK signaling pathways by up-regulating MKP1 expression, reduced apoptosis and the inflammatory reaction, and exerted a neuroprotective effect following cerebral ischemia/reperfusion injury.

Key words: nerve regeneration, cerebral ischemia/reperfusion injury, let-7, mitogen-activated protein kinase phosphatase-1, apoptosis, microglia, inflammation, mitogen-activated protein kinase, neurons, c-Jun N-terminal kinase, gene knockdown, brain injury, neural regeneration