Transcriptional Regulation of the Astrocytic Excitatory Amino Acid Transporter 1 (EAAT1) via NF-κB and Yin Yang 1 (YY1)
Transcriptional Regulation of the Astrocytic Excitatory Amino Acid Transporter 1 (EAAT1) via NF-κB and Yin Yang 1 (YY1)
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DOI：
10.1074/jbc.m115.649327
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发表时间：
2015-09-25
影响因子：
4.8
通讯作者：
Lee, Eunsook
中科院分区：
文献类型：
--
作者：
Karki, Pratap;Kim, Clifford;Lee, Eunsook
星形胶质细胞谷氨酸转运蛋白兴奋性氨基酸转运蛋白（EAAT）1，也称为谷氨酸天冬氨酸转运蛋白（GLAST）在啮齿类动物中，是两种神经胶质谷氨酸转运蛋白之一，负责从突触裂隙中清除过量的谷氨酸，以防止兴奋性毒性神经元死亡。尽管EAAT 1在神经生理学功能中发挥重要作用，但其在转录水平上的调控机制仍有待建立。在这里，我们报告说，NF-κ B是EAAT 1的主要正转录因子，由以下支持：1）EAAT 1含有两个NF-κ B的共有位点，2）NF-κ B结合位点的突变降低EAAT 1启动子活性，3）NF-κ B的激活增加，而NF-κ B的抑制降低EAAT 1启动子活性和mRNA/蛋白水平。EGF通过NF-κ B B增加EAAT 1 mRNA/蛋白水平和谷氨酸摄取。转录因子阴阳1（YY 1）作为EAAT 1的关键负调控因子发挥作用，这得到以下支持：1）EAAT 1启动子含有YY 1的多个共有位点，2）YY 1的过表达降低EAAT 1启动子活性和mRNA/蛋白水平，以及3）YY 1的敲低增加EAAT 1启动子活性和mRNA/蛋白水平。锰通过YY 1降低EAAT 1表达。表观遗传修饰剂组蛋白脱乙酰酶（HDACs）作为YY 1的共阻遏物，以进一步降低EAAT 1启动子活性，而抑制HDACs逆转锰诱导的EAAT 1表达降低。综上所述，我们的研究结果表明，NF-κ B是EAAT 1的一个重要的正调节因子，介导EGF的刺激作用，而YY 1是EAAT 1的负调节因子，HDAC作为共阻遏物，介导锰对EAAT 1调节的抑制作用。
Astrocytic glutamate transporter excitatory amino acid transporter (EAAT) 1, also known as glutamate aspartate transporter (GLAST) in rodents, is one of two glial glutamate transporters that are responsible for removing excess glutamate from synaptic clefts to prevent excitotoxic neuronal death. Despite its important role in neurophysiological functions, the molecular mechanisms of EAAT1 regulation at the transcriptional level remain to be established. Here, we report that NF-kappa B is a main positive transcription factor for EAAT1, supported by the following: 1) EAAT1 contains two consensus sites for NF-kappa B, 2) mutation of NF-kappa B binding sites decreased EAAT1 promoter activity, and 3) activation of NF-kappa B increased, whereas inhibition of NF-kappa B decreased EAAT1 promoter activity and mRNA/protein levels. EGF increased EAAT1 mRNA/protein levels and glutamate uptake via NF-kappa B. The transcription factor yin yang 1 (YY1) plays a role as a critical negative regulator of EAAT1, supported by the following: 1) the EAAT1 promoter contains multiple consensus sites for YY1, 2) overexpression of YY1 decreased EAAT1 promoter activity and mRNA/protein levels, and 3) knockdown of YY1 increased EAAT1 promoter activity and mRNA/protein levels. Manganese decreased EAAT1 expression via YY1. Epigenetic modifiers histone deacetylases (HDACs) served as co-repressors of YY1 to further decrease EAAT1 promoter activity, whereas inhibition of HDACs reversed manganese-induced decrease of EAAT1 expression. Taken together, our findings suggest that NF-kappa B is a critical positive regulator of EAAT1, mediating the stimulatory effects of EGF, whereas YY1 is a negative regulator of EAAT1 with HDACs as co-repressors, mediating the inhibitory effects of manganese on EAAT1 regulation.