Exploiting Metabolism to Uncloak Epstein-Barr Virus Immunogens in Latently Infected B-cells

项目摘要 爱泼斯坦-巴尔病毒(EBV)通过唾液传播，在那里它建立口咽部 感染，侵入扁桃体，并在B细胞室定居。经口传播的EBV是 传染性单核细胞增多症以及多发性B细胞和上皮性癌症的原因，包括 Burkitt淋巴瘤和鼻咽癌。关于如何做到这一点，还有很多需要了解的 病毒基因组的表观遗传调节使其能够定植在口咽和扁桃体上，以 使95%的成年人持续感染，每年导致20万人癌症。在扁桃体中 记忆B细胞，EBV表达单一的、低免疫原性的抗原。BL，它可以呈现 作为颌骨、面部和眼眶的肿瘤，使用类似的病毒程序来逃避抗EBV T细胞 回应。相比之下，EBV在有口腔毛发的艾滋病患者中表达近80种病毒蛋白 舌白斑，和免疫原性八潜伏期蛋白在后 移植性淋巴瘤。在最初的博士后阶段，申请人使用了两个CRISPR 筛选对EB病毒潜伏期有重要影响的B细胞因子。这些都提供了洞察力 进入表观遗传途径，限制B细胞中溶解周期和潜伏基因的表达 突出的表观遗传酶，启动并维持高水平的DNA甲基化 EBV基因组在这种高度受限的潜伏期形式。EBV DNA甲基化去甲基化的扰动 抑制EBV抗原的表达，并使Burkitt细胞对CD8+T细胞识别敏感。然而， 关于感染的B细胞代谢和表观遗传途径之间的相互作用，人们知之甚少。 必须发生这种情况才能为DNA和组蛋白修饰提供甲基。申请人 假设潜伏感染EBV的B细胞颠覆蛋氨酸和叶酸代谢 抑制免疫原性EBV所需的EBV基因组高甲基化驱动途径 基因产物和T细胞免疫逃避。在指导K99阶段，申请者将1) 确定蛋氨酸代谢如何促进EBV基因组高甲基化和沉默 在潜伏感染的B细胞和EBV癌蛋白中，以及2)表征了 潜伏感染细胞中的叶酸循环和EBV基因组甲基化。在R00阶段， 申请者将进行独立研究，以确定潜伏的EBV计划如何改变B细胞 在DNA和组蛋白水平上加强病毒基因组表观遗传状态的代谢途径 甲基化。总的来说，这些研究将开辟EBV生物学的新领域，并有望 支持新的治疗方法。职业发展计划将为申请者做好准备 作为一名具有多学科研究方法的调查员，过渡到独立 病毒/宿主相互作用的代谢控制。

Project Summary Epstein-Barr virus (EBV) is spread through the saliva, where it establishes oropharyngeal infection, invades the tonsils and colonizes the B-cell compartment. Orally transmitted EBV is the cause of infectious mononucleosis and of multiple B-cell and epithelial cancers, including Burkitt lymphoma (BL) and nasopharyngeal carcinoma. Much remains to be learned about how epigenetic regulation of the viral genome enables it to colonize the oropharynx and tonsils to establish persistent infection of >95% adults and to cause 200,000 cancers per year. In tonsillar memory B-cells, EBV expresses a single, poorly immunogenic antigen. BL, which can present as tumors of the jaws, face and orbit, use a similar viral program to evade anti-EBV T-cell responses. By contrast, EBV expresses nearly 80 viral proteins in AIDS patients with oral hairy leukoplakia of the tongue, and as many as immunogenic eight latency proteins in post- transplant lymphoma. During the initial post-doctoral period, the applicant used two CRISPR screens to characterize B-cell factors important for EBV latency in BL. These provided insights into epigenetic pathways that restrict expression of lytic cycle and latency genes in B-cells and highlighted epigenetic enzymes that initiate and maintain a high level of DNA methylation of the EBV genome in this highly restricted form of latency. Perturbation of EBV DNA methylation de- represses EBV antigen expression and sensitizes Burkitt cells to CD8+ T-cell recognition. Yet, little is known about cross-talk between infected B-cell metabolism and epigenetic pathways, which must occur to supply methyl groups for DNA and histone modification. The applicant hypothesizes that latently EBV-infected B cells subvert methionine and folate metabolism pathways to drive EBV genome hypermethylation necessary for silencing of immunogenic EBV gene products and T-cell immunoevasion. During the mentored K99 phase, the applicant will 1) identify how methionine metabolism contributes to EBV genome hypermethylation and silencing in latently infected B-cells and EBV oncoproteins, and 2) characterize the interplay between the folate cycle and EBV genome methylation in latently-infected cells. During the R00 phase, the applicant will perform independent research to identify how latent EBV programs alter B-cell metabolic pathways to reinforce viral genome epigenetic states at the level of DNA and histone methylation. Collectively, these studies will open a new area of EBV biology and promise to support novel therapeutic approaches. The career development plan will prepare the applicant for transition to independence as an investigator with a multi-disciplinary approach to study metabolomic control of virus/host interactions.