MiR-34b Protects Against Focal Cerebral Ischemia-Reperfusion (I/R) Injury in Rat by Targeting Keap1
MiR-34b Protects Against Focal Cerebral Ischemia-Reperfusion (I/R) Injury in Rat by Targeting Keap1
复制标题
DOI：
10.1016/j.jstrokecerebrovasdis.2018.08.023
复制
发表时间：
2019-01-01
影响因子：
2.5
通讯作者：
Luan, Xinping
中科院分区：
文献类型：
--
作者：
Huang, Rong;Ma, Juan;Luan, Xinping
缺血性卒中是全球导致死亡和残疾的主要原因之一，被认为是一个主要的公共卫生问题。了解缺血/再灌注(I/R)所致氧化应激损伤的机制可能为缺血性卒中提供新的治疗方法。Kelch样ECH相关蛋白1(Keap1)/核因子E2相关因子2(Nrf2)/抗氧化反应元件(ARE)信号通路被认为是细胞抵御氧化应激的主要途径。本研究旨在探讨miR-34b/Keap1调节局灶性脑I/R氧化损伤的分子机制。MIR-34b被预测靶向于大鼠Keap1的3‘-UTR。大鼠局灶性脑I/R后，miR-34b表达呈时间依赖性下调，miR-34b过表达可通过降低脑梗塞体积、神经功能评分、一氧化氮(NO)和(3-硝基酪氨酸)3-NT水平，升高总超氧化物歧化酶和锰超氧化物歧化酶(MnSOD)水平，改善大脑中动脉阻塞(MCAO)大鼠氧化应激损伤。通过直接靶向，miR-34b可以抑制Keap1的蛋白水平，提高Nrf2和HO-1的蛋白水平。在分子机制上，Keap1过表达加剧了氧化应激损伤，而miR-34b改善了H_2O_2诱导的氧化应激损伤；miR-34b的作用可被Keap1过表达部分减弱，提示miR-34b通过靶向Keap1在体外和体内调控氧化应激损伤。综上所述，我们证明miR-34b通过靶向Keap1及其下游的Keap1/Nrf2信号通路，对MCAO大鼠局灶性脑I/R诱导的氧化应激损伤和H_2O_2诱导的大鼠神经母细胞B35细胞的氧化应激损伤具有保护作用。我们从miRNA调控的角度提供了一种新的局灶性脑I/R损伤机制。
Ischemic stroke is one of the leading causes of death and disability globally and has been regarded as a major public health problem. Understanding the mechanism of ischemia/reperfusion (I/R)-induced oxidative stress injury may provide new treatment for ischemic stroke. Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor 2 (Nrf2)/antioxidant response elements (ARE) signaling pathway has been considered to be the major cellular defense against oxidative stress. In the present study, our objective is to evaluate the molecular mechanism of miR-34b /Keap1 in modulating focal cerebral I/R induced oxidative injury. miR-34b was predicted to target the 3'-UTR of the rat Keap1. After focal cerebral I/R, miR-34b expression was downregulated in a time-dependent manner; miR-34b overexpression ameliorated I/R-induced oxidative stress injury in middle cerebral artery occlusion (MCAO) rats by reducing the infarction volume, the neurological severity scores, the levels of nitric oxide (NO) and (3-nitrotyrosine) 3-NT while increasing total (superoxide dismutases) SOD and manganese SOD (MnSOD). Through direct targeting, miR-34b could suppress the protein levels of Keap1 and increase the protein levels of Nrf2 and heme oxygenase (HO-1). Regarding the molecular mechanism, Keap1 overexpression exacerbated, while miR-34b improved H2O2-induced oxidative stress injury; the effect of miR-34b could be partially attenuated by Keap1 overexpression, suggesting that miR-34b modulated oxidative stress injury in vitro and in vivo through targeting Keap1. Taken together, we demonstrate that miR-34b protects against focal cerebral I/R-induced oxidative stress injury in MCAO rats and H2O2-induced oxidative stress injury in rat neuroblast B35 cells through targeting Keap1 and downstream Keap1/Nrf2 signaling pathway. We provided a novel mechanism of focal cerebral I/R injury from the perspective of miRNA regulation.