Epstein-Barr 病毒或人类疱疹病毒 4 (EBV/HHV-4) 是一种无处不在的致癌病毒,在病因学上与各种 B 细胞淋巴瘤和上皮癌相关。与病毒蛋白持续表达相关的恶性转化通常会解除对宿主细胞机制的调节,并且 EBV 感染与活性氧水平升高有关。在这里,我们研究了谷氨酸转运蛋白 EAAT3 在调节抗氧化系统中的作用,作为 EBV 感染细胞抵抗病毒诱导的氧化应激的保护机制。我们的研究表明,EAAT3 的表达被上调并定位于 EBV 潜伏感染和新发 EBV 感染细胞的质膜。EAAT3 受感染细胞中的转录因子 NFAT5 调节。发现膜定位的 EAAT3 参与将谷氨酸从细胞外空间运输到细胞中,因为 EAAT3 和 NFAT5 抑制剂显着降低了 EBV 潜伏感染细胞中的细胞内谷氨酸水平。此外,我们的数据表明在用 EAAT3 抑制剂治疗后细胞内谷胱甘肽水平显着降低。总的来说,我们的结果表明,谷氨酸转运蛋白 EAAT3 的上调是 EBV 感染细胞的一种适应,以维持细胞氧化还原稳态以抵抗病毒诱导的氧化应激,并且这种细胞平衡可以通过靶向 EAAT3 以阻止 EBV 相关的治疗来破坏癌症。由于 EAAT3 和 NFAT5 抑制剂显着降低了 EBV 潜伏感染细胞中的细胞内谷氨酸水平。此外,我们的数据表明在用 EAAT3 抑制剂治疗后细胞内谷胱甘肽水平显着降低。总的来说,我们的结果表明,谷氨酸转运蛋白 EAAT3 的上调是 EBV 感染细胞的一种适应,以维持细胞氧化还原稳态以抵抗病毒诱导的氧化应激,并且这种细胞平衡可以通过靶向 EAAT3 以阻止 EBV 相关的治疗来破坏癌症。由于 EAAT3 和 NFAT5 抑制剂显着降低了 EBV 潜伏感染细胞中的细胞内谷氨酸水平。此外,我们的数据表明在用 EAAT3 抑制剂治疗后细胞内谷胱甘肽水平显着降低。总的来说,我们的结果表明,谷氨酸转运蛋白 EAAT3 的上调是 EBV 感染细胞的一种适应,以维持细胞氧化还原稳态以抵抗病毒诱导的氧化应激,并且这种细胞平衡可以通过靶向 EAAT3 以阻止 EBV 相关的治疗来破坏癌症。
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Epstein–Barr virus infection controls the concentration of the intracellular antioxidant glutathione by upregulation of the glutamate transporter EAAT3 in tumor cells
Epstein–Barr virus or human herpesvirus 4 (EBV/HHV-4) is an omnipresent oncovirus etiologically associated with various B-cell lymphomas and epithelial cancers. The malignant transformation associated with the persistent expression of viral proteins often deregulates the host cellular machinery and EBV infection is coupled to elevated levels of reactive oxygen species. Here, we investigated the role that the glutamate transporter EAAT3 plays in regulating the antioxidant system as a protective mechanism of EBV-infected cells against the virus-induced oxidative stress. Our study demonstrated that the expression of EAAT3 was upregulated and localized to the plasma membrane in EBV latently infected and de novo EBV-infected cells. EAAT3 was regulated by the transcription factor NFAT5 in the infected cells. Membrane localized EAAT3 was found to be involved in the transportation of glutamate from the extracellular space into the cell, as EAAT3 and NFAT5 inhibitors markedly reduced the levels of intracellular glutamate levels in EBV latently infected cells. Additionally, our data demonstrated a notable decrease in the intracellular glutathione levels following treatment with an EAAT3 inhibitor. Collectively, our results suggest that upregulation of the glutamate transporter EAAT3 is an adaptation of EBV-infected cells to maintain cellular redox homeostasis against the virus-induced oxidative stress, and that this cellular balance could be therapeutically destroyed by targeting EAAT3 to impede EBV-associated cancers.