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

调节 Epstein-Barr 病毒介导的 B 细胞生长转化的宿主途径

• 批准号: 9976477
• 负责人: Micah A. Luftig
• 金额: $ 37.17万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9976477
• 关键词: Adult; Apoptosis; Autophagocytosis; B Cell Proliferation; B-Cell Lymphomas; B-Lymphocytes; Cancer Etiology; Cell Cycle Arrest; Cell Maturation; Cell division; Cells; Cellular Metabolic Process; DNA Damage; Data; Disease; Energy Metabolism; Epstein-Barr Virus Infections; Epstein-Barr Virus latency; FRAP1 gene; Failure; GTP-Binding Protein alpha Subunits, Gs; Gene Expression; Genes; Glucose; Glucose Transporter; Goals; Growth; Herpesviridae; Human; Human Herpesvirus 4; Immune; Immune response; Immunosuppression; In Vitro; Infection; LMP1; Latent virus infection phase; Lead; Lymphoma; Mediating; Membrane Proteins; Metabolic; Metabolism; Mitochondria; Modeling; Molecular; NF-kappa B; Nucleosides; Nucleotides; Outcome; Oxidative Phosphorylation; Pathway interactions; Process; Proliferating; Purine Nucleotides; Purines; Research; Respiration; Role; Signal Transduction; Starvation; Surface; TP53 gene; Testing; Time; Viral; Virus; Virus Diseases; Virus Integration; Virus Latency; Work; adenylate kinase; base; cell growth; cell transformation; gammaherpesvirus; latent infection; lymphoblastoid cell line; new therapeutic target; nuclear respiratory factor; nutrient deprivation; prevent; programs; response; senescence; telomere; transcription factor

Epstein-Barr virus is a γ-herpesvirus that infects nearly 95% of adults worldwide. A potent immune response prevents disease in the majority of those infected. However, immune suppression can lead to latent EBV-driven B-cell lymphomas. It is our ultimate goal to define the mechanisms by which EBV establishes latency and how these processes go awry leading to disease. In this proposal, we aim to define the cellular metabolic restriction to EBV transformation of primary human B cells. It is our central hypothesis that EBV-induced hyper-proliferation initially upon infection leads to an imbalance in energy metabolism resulting in a depletion of purine nucleotides and telomere-specific DNA damage causing permanent cell cycle arrest. We have formulated our hypothesis based on preliminary data characterizing the metabolic state of EBV-infected cells that begin to proliferate, then either arrest or continue to long-term outgrowth. In cells that arrest, we detected a failure to up-regulate oxidative phosphorylation as well as genes controlled by nuclear respiratory factor 1. Arrested cells display activated p53 and AMP kinase, which suppresses mTOR leading to elevated basal autophagy. Arrested cells also have depleted purine nucleotides and providing exogenous nucleosides rescues transformation of primary B cells by EBV. Finally, expression of the viral latent membrane proteins is delayed until late infection and their activation of NF-kappaB and Akt mitigate autophagy in B cells through inducing surface expression of the glucose transporter, Glut1. Based on these data, we propose that early EBV infected cells display elevated autophagy as a mechanism to compensate for nutrient deprivation during hyperproliferation. These starved cells are depleted fur purine nucleotides triggering a DNA damage response that causes permanent growth arrest. At later times during infection, EBV suppresses autophagy through increased glucose import. The rationale for this proposed research is that understanding the control of B-cell metabolism by EBV during latent infection will provide important clues to how this virus mimics B-cell maturation and may provide new therapeutic targets for EBV-associated lymphomas. We plan to test our central hypothesis and complete the objectives outlined in this proposal through the following specific aims: 1) Determine the mechanism by which EBV overcomes the early metabolic barrier to B-cell transformation, 2) Determine the consequences of nucleotide pool imbalance on the growth-suppressive DDR at telomeres following EBV-mediated B-cell infection, and 3) Define the role of NF-kappaB/Akt-mediated glucose import in suppressing nutrient deprivation-induced autophagy.

EB病毒是一种γ-疱疹病毒，感染全球近95%的成年人。有效的免疫反应可以预防大多数感染者的疾病。然而，免疫抑制可导致潜伏性EBV驱动的B细胞淋巴瘤。我们的最终目标是确定EBV建立潜伏期的机制以及这些过程如何出错导致疾病。在这个提议中，我们的目标是定义原代人B细胞的EBV转化的细胞代谢限制。我们的中心假设是，EBV诱导的过度增殖最初在感染后导致能量代谢失衡，导致嘌呤核苷酸耗尽和端粒特异性DNA损伤，导致永久性细胞周期停滞。我们根据表征EBV感染细胞代谢状态的初步数据制定了我们的假设，EBV感染细胞开始增殖，然后停止或继续长期生长。在停滞的细胞中，我们检测到未能上调氧化磷酸化以及由核呼吸因子1控制的基因。停滞的细胞显示激活的p53和AMP激酶，其抑制mTOR，导致基础自噬升高。停滞的细胞还具有耗尽的嘌呤核苷酸，并且提供外源核苷挽救了EBV对原代B细胞的转化。最后，病毒潜伏膜蛋白的表达被延迟直到晚期感染，并且它们对NF-κ B和Akt的激活通过诱导葡萄糖转运蛋白Glut 1的表面表达来减轻B细胞中的自噬。基于这些数据，我们提出早期EBV感染的细胞显示出升高的自噬作为一种机制来补偿过度增殖期间的营养剥夺。这些饥饿的细胞耗尽了嘌呤核苷酸，引发DNA损伤反应，导致永久性生长停滞。在感染后期，EBV通过增加葡萄糖输入抑制自噬。这项研究的基本原理是，了解潜伏感染期间EBV对B细胞代谢的控制将为这种病毒如何模拟B细胞成熟提供重要线索，并可能为EBV相关淋巴瘤提供新的治疗靶点。我们计划通过以下具体目标来检验我们的中心假设并完成本提案中概述的目标：1）确定EBV克服B细胞转化的早期代谢障碍的机制，2）确定EBV介导的B细胞感染后核苷酸库不平衡对端粒处生长抑制性DDR的后果，和3）确定NF-κ B/Akt介导的葡萄糖输入在抑制营养缺乏诱导的自噬中的作用。