Host pathways regulating Epstein-Barr virus-mediated B cell growth transformation

摘要 我们的最终目标是确定EB病毒介导的代谢控制的分子基础，这对B细胞至关重要 肿瘤发生学。在这项提案中，我们将重点研究EBV如何促进氧化平衡上调 磷酸化(OXPHOS)和糖酵解支持B细胞永生化和肿瘤发生。它是我们的中心 病毒潜伏转录因子EBNA-LP模拟OXPHOS转录的假说 辅活化子pGC-1，而糖酵解和氧化还原平衡通过病毒上调乳酸来维持 转运蛋白MCT1和MCT4。我们基于初步数据制定了我们的中心假设，包括 定义EBNA-LP和OXPHOS转录因子之间相互作用的正交方法定义了一个 EBNA-LP上新的翻译后修饰，并表征了抑制的代谢后果 病毒介导的乳酸出口。我们发现病毒EBNA-LP蛋白与NRF-1、ERR和YY-1结合。 1模拟细胞共激活因子pGC-1。我们描述了EBNA-LP的一种新的翻译后修饰， 我们提出的羟脯氨酸对于高阶复合体的形成是关键的，使转录 激活。与EBNA-LP促进的OXPHOS增加平衡，糖酵解酶上调 通过EBNA2和c-myc导致乳酸在细胞中积累，这些乳酸必须输出以维持B细胞 扩散。我们发现细胞内的单羧酸转运体MCT1和MCT4是受时间调控的 通过EBV维持NAD+/NADH比值和谷胱甘肽水平来维持B细胞的增殖 活性氧物种的积累。因此，这项拟议研究的理由是 了解EB病毒如何在B细胞永生化过程中调节细胞代谢可能会揭示新的 针对EBV感染的B细胞淋巴瘤的治疗方式。我们计划测试我们的中心假设 通过以下两个具体目标完成本提案中的目标：i)确定分子 EBNA-LP协同EBV调节的氧化磷酸化使幼稚B永生化的机制 细胞和ii)确定病毒介导的单羧酸转运体的时间调节机制， MCT1和MCT4，通过B细胞的生长及其拮抗的后果。

ABSTRACT It is our ultimate goal to define the molecular basis for EBV-mediated metabolic control critical for B-cell tumorigenesis. In this proposal, we will focus on how EBV promotes the balanced upregulation of oxidative phosphorylation (OXPHOS) and glycolysis supporting B-cell immortalization and tumorigenesis. It is our central hypothesis that the viral latent transcription factor, EBNA-LP, functions as a mimic of the OXPHOS transcriptional co-activator PGC-1 while glycolysis and redox balance are maintained through viral upregulation of the lactate transporters MCT1 and 4. We have formulated our central hypothesis based on preliminary data including orthogonal approaches that define interactions between EBNA-LP and OXPHOS transcription factors, define a new post-translational modification on EBNA-LP, and characterize the metabolic consequences of suppressing viral-mediated lactate export. We found that the viral EBNA-LP protein associates with NRF-1, ERR, and YY- 1 mimicking the cellular co-activator PGC-1. We describe a novel post-translational modification of EBNA-LP, hydroxyprolination, that we propose is critical for higher order complex formation enabling transcriptional activation. Balanced with an increase in OXPHOS promoted by EBNA-LP, the upregulation of glycolytic enzymes by EBNA2 and c-MYC leads to an accumulation of lactate in cells that must be exported to sustain B-cell proliferation. We found that cellular monocarboxylate transporters, MCT1 and MCT4, are temporally regulated by EBV to sustain B-cell proliferation through maintaining NAD+/NADH ratios and glutathione levels to counter the accumulation of reactive oxygen species. Therefore, the rationale for this proposed research is that understanding how EBV regulates cellular metabolism during B-cell immortalization could reveal novel therapeutic modalities to target EBV-infected B-cell lymphomas. We plan to test our central hypothesis and complete the objectives in this proposal through the following two specific aims: i) to determine the molecular mechanism by which EBNA-LP coordinates EBV-regulated oxidative phosphorylation to immortalize naïve B cells and ii) to define the viral-mediated mechanism for temporal regulation of the monocarboxylate transporters, MCT1 and 4, through B-cell outgrowth and the consequences of their antagonism.