Transient expression of Nxf, a bHLH-PAS transactivator induced by neuronal preconditioning, confers neuroprotection in cultured cells
Transient expression of Nxf, a bHLH-PAS transactivator induced by neuronal preconditioning, confers neuroprotection in cultured cells
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DOI：
10.1016/j.brainres.2006.11.083
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发表时间：
2007-03-02
期刊：
影响因子：
2.9
通讯作者：
Sabourin, Luc A.
中科院分区：
文献类型：
--
作者：
Hester, Ian;McKee, Sarah;Sabourin, Luc A.
皮质扩散性抑制(CSD)诱导神经元去极化波，为随后的大鼠脑缺血事件提供神经保护。为了深入了解CSD诱导的分子机制，我们使用代表性差异分析(RDA)在体内鉴定了钾去极化诱导的mRNAs。利用这种方法，我们已经克隆了编码SIM2相关的bHLH-PAS蛋白Nxf的cDNA。我们的结果证实，在慢性阻塞性肺疾病后，Nxf的mRNA和蛋白在大脑皮层神经元中迅速和瞬时表达。记者分析表明，Nxf是一个转录激活因子，与bHLH-PAS亚类辅助因子ARNT2相关。腺病毒介导的表位标记的Nxf的表达导致细胞死亡和Bax基因在培养细胞中的直接激活。然而，RNA干扰研究表明，在培养的F-11细胞中，内源性Nxf是通过预适应实现最佳神经保护所必需的。综上所述，我们的数据表明，Nxf是一种新的bHLH-PAS反式激活剂，它是由预适应瞬时诱导的，其持续表达是有害的。Nxf的鉴定可能代表着我们理解脑预适应和损伤的分子机制的重要一步。(C)2006爱思唯尔B.V.保留所有权利。
Cortical spreading depression (CSD) induces waves of neuronal depolarization that confer neuroprotection to subsequent ischemic events in the rat brain. To gain insights into the molecular mechanisms elicited by CSD, we used representational difference analysis (RDA) to identify mRNAs induced by potassium depolarization in vivo. Using this approach, we have isolated a cDNA encoding the SIM2-related bHLH-PAS protein Nxf. Our results confirm that Nxf mRNA and protein are rapidly and transiently expressed in cortical neurons following CSD. Reporter assays show that Nxf is a transcriptional activator that associates with the bHLH-PAS sub-class co-factor ARNT2. Adenovirus-mediated expression of epitope-tagged Nxf results in cell death and the direct activation of the Bax gene in cultured cells. However, RNA interference studies show that endogenous Nxf is required for optimal neuroprotection by preconditioning in cultured F-11 cells. Together, our data indicate that Nxf is a novel bHLH-PAS transactivator transiently induced by preconditioning and that its sustained expression is detrimental. The identification of Nxf may represent an important step in our understanding of the molecular mechanisms of brain preconditioning and injury. (c) 2006 Elsevier B.V. All rights reserved.