Huang Weidong, Liu Xiaobin, Cao Jie, Meng Facai, Li Min, Chen Bo, Zhang Jie
Neurosurgery, Shaanxi Provincial People's Hospital, No. 256 Youyi Western Road, Xi'an, 710068, China,
J Mol Neurosci. 2015 Apr;55(4):821-9. doi: 10.1007/s12031-014-0434-0. Epub 2014 Oct 16.
microRNA-134 (miR-134) has been reported to be a brain-specific miRNA and is differently expressed in brain tissues subjected to ischemic injury. However, the underlying mechanism of miR-134 in regulating cerebral ischemic injury remains poorly understood. The current study was designed to delineate the molecular basis of miR-134 in regulating cerebral ischemic injury. Using the oxygen-glucose deprivation (OGD) model of hippocampal neuron ischemia in vitro, we found that the overexpression of miR-134 mediated by recombinant adeno-associated virus (AAV) vector infection significantly promoted neuron death induced by OGD/reoxygenation, whereas the inhibition of miR-134 provided protective effects against OGD/reoxygenation-induced cell death. Moreover, cyclic AMP (cAMP) response element-binding protein (CREB) as a putative target of miR-134 was downregulated and upregulated by miR-134 overexpression or inhibition, respectively. The direct interaction between miR-134 and the 3'-untranslated region (UTR) of CREB mRNA was further confirmed by dual-luciferase reporter assay. Overexpression of miR-134 also inhibited the expression of the downstream gene of CREB, including brain-derived neurotrophic factor (BDNF) and the anti-apoptotic gene Bcl-2, whereas the inhibition of miR-134 upregulated the expression of BDNF and Bcl-2 in neurons after OGD/reoxygenation. Notably, the knockdown of CREB by CREB siRNA apparently abrogated the protective effect of anti-miR-134 on OGD/reoxygenation-induced cell death. Taken together, our study suggests that downregulation of miR-134 alleviates ischemic injury through enhancing CREB expression and downstream genes, providing a promising and potential therapeutic target for cerebral ischemic injury.
据报道，微小RNA - 134（miR - 134）是一种脑特异性微小RNA，在遭受缺血性损伤的脑组织中表达存在差异。然而，miR - 134调控脑缺血性损伤的潜在机制仍知之甚少。本研究旨在阐明miR - 134调控脑缺血性损伤的分子基础。利用体外海马神经元缺血的氧 - 葡萄糖剥夺（OGD）模型，我们发现重组腺相关病毒（AAV）载体感染介导的miR - 134过表达显著促进了OGD/复氧诱导的神经元死亡，而抑制miR - 134则对OGD/复氧诱导的细胞死亡具有保护作用。此外，环磷酸腺苷（cAMP）反应元件结合蛋白（CREB）作为miR - 134的假定靶标，分别被miR - 134过表达或抑制而下调或上调。双荧光素酶报告基因检测进一步证实了miR - 134与CREB mRNA的3'非翻译区（UTR）之间的直接相互作用。miR - 134过表达还抑制了CREB下游基因的表达，包括脑源性神经营养因子（BDNF）和抗凋亡基因Bcl - 2，而抑制miR - 134则上调了OGD/复氧后神经元中BDNF和Bcl - 2的表达。值得注意的是，CREB siRNA敲低CREB明显消除了抗miR - 134对OGD/复氧诱导的细胞死亡的保护作用。综上所述，我们的研究表明，miR - 134的下调通过增强CREB表达及其下游基因来减轻缺血性损伤，为脑缺血性损伤提供了一个有前景的潜在治疗靶点。
