Defining host mechanisms that restrict EBV lytic reactivation

摘要 Epstein-Barr病毒（EBV）是一种非常普遍的人类疱疹病毒，感染全球约95%的人。 成年人口。EB病毒通过唾液传播，并在口腔中建立感染， 然后在记忆B细胞中建立潜伏感染。在大多数人中，这种感染将保持良性， 但EB病毒相关疾病包括传染性单核细胞增多症和癌症，更常见于免疫系统疾病， 妥协的人。潜伏性感染和溶解性感染之间的平衡受到严格控制和理解 这一过程的调节对从口腔中的病毒持久性 粘膜的策略，以消除潜伏感染的肿瘤细胞。EB病毒在各种不同的免疫反应中重新激活， 应激源包括DNA损伤、缺氧、组蛋白脱乙酰酶抑制剂和B细胞受体活化。一 在体外和体内都观察到的普遍现象是细胞对溶解性细胞因子具有异质性反应。 诱导刺激在一小部分细胞中，病毒完全重新激活，而其他细胞则完全不受感染， 仅部分地通过裂解周期进展，导致流产感染。为了更好地了解这些细胞 EBV裂解性再激活后的命运，我的实验室最近完成了一个单细胞RNA测序实验， 再活化EBV+ B淋巴瘤细胞。我们观察到难治性， 败育和生产性裂解细胞。这包括已知的EBV限制性因子MYC的高表达， STAT 3在难治性细胞中，但以前未知的流产细胞群的标志物：一种特征为 升高的IL-6受体和另一种由通过NF κ B B途径的促存活信号传导定义。基于我们 单细胞数据和先前的研究，我假设EBV诱导的DNA损伤反应导致IL-6 产生，进而通过IL-6受体促进流产、抗病毒状态，并最终促进 存活NF κ B B信号传导。除了定义宿主防御EB病毒再激活的机制外，这项工作 也具有重要的临床意义，因为裂解诱导疗法目前正用于EBV相关的 恶性肿瘤。了解限制成功裂解再激活的宿主因素可能会导致更有效的 未来的治疗策略。此外，这些发现可能对其他人如何 疱疹病毒的重新激活以及潜伏感染细胞如何交流以调节这一过程。

ABSTRACT Epstein-Barr virus (EBV) is an extremely pervasive human herpesvirus, infecting approximately 95% of the global population by adulthood. EBV is transmitted through saliva and establishes infection in the oral cavity where it then establishes a latent infection for life in memory B cells. In most individuals this infection will remain benign, but EBV-associated diseases include infectious mononucleosis and cancers, more commonly in immune- compromised individuals. The balance between latent and lytic infection is under tight control and understanding the regulation of this process has broad implications for processes ranging from viral persistence in the oral mucosa to strategies to eliminate latently infected tumor cells. EBV reactivates in response to a diverse range of stressors including DNA damage, hypoxia, histone deacetylase inhibitors and activation of the B-cell receptor. A pervasive phenomenon, observed both in vitro and in vivo, is that cells have a heterogenous response to lytic induction stimuli. In a fraction of cells, the virus fully reactivates, while others remain completely refractory or only partially progress through the lytic cycle leading to an abortive infection. To better understand these cell fates after EBV lytic reactivation, my lab recently completed a single-cell RNA seq experiment of resting and reactivated EBV+ B lymphoma cells. We observed differential host gene expression patterns between refractory, abortive, and productive lytic cells. This included high expression of the known EBV restriction factors MYC and STAT3 in the refractory cells, but previously unknown markers of abortive cell populations: one characterized by elevated IL-6 receptor and the other defined by pro-survival signaling through the NFB pathway. Based on our single-cell data and prior studies, I hypothesize that an EBV induced DNA damage response leads to IL-6 production, which in turn promotes an abortive, antiviral state through the IL-6 receptor and ultimately pro- survival NFB signaling. In addition to defining mechanisms of host defense from EBV reactivation, this work also has important clinical ramifications as lytic induction therapies are currently in trials for EBV-associated malignancies. Understanding host factors that restrict successful lytic reactivation could lead to more effective therapeutic strategies in the future. Furthermore, these findings could have broad implications for how other herpesviruses reactivate and how latently infected cells communicate to regulate this process.