Ocular HSV: Mechanism of virus reactivation

项目摘要 在原发的眼部HSV-1感染后，病毒在眼睛内复制，并在 三叉神经节(Tg)。在潜伏感染的个体中，病毒偶尔会重新激活并传播回 导致复发性疾病的眼睛。潜伏期的重新激活是眼病的主要原因。然而， 这一过程背后的机制没有得到很好的定义，目前也不清楚是否重新激活 反映延迟机制或中断延迟的独立机制中的故障。它由来已久。 HSV-1潜伏期相关转录本(LAT)的持续表达是潜伏期的特征， 这与抑制细胞凋亡和调节T细胞对感染的感觉的反应有关 神经元。最近，我们发现在感染LAT(-)病毒的小鼠的TG中，HSV-1受体， 而其他HSV-1受体的表达则无明显下调。此外，HSV-1潜伏期和 与野生型小鼠相比，HVEM-/-小鼠的再激活显著减少。值得注意的是，LAT 上调映射到最近描述的两个小的非编码LAT RNA(SncRNA1和SncRNA1)的HVEM的功能 2)，由于hvem在瞬时转染后表达上调， 编码RNA。同时，我们还发现了病毒糖蛋白gD，能够结合HIV并触发其 通过NF-κB的信号在潜伏感染的TG中低水平表达。总的来说，我们的初步数据 提供令人信服的证据支持LAT可以增强潜伏期重新激活和T细胞的假设 通过上调Hvem，进而促进HSV-1的重新激活，可能通过促进 Gd与HVEM的结合。尽管表达杆状病毒凋亡抑制蛋白基因的LAT(-)病毒 (CpIAP)具有与野生型LAT(+)病毒相似的潜伏期，这种重组病毒不会增加HVEM 水平表明这种重新激活机制不会通过调节反应性来促进重新激活 到细胞凋亡。相反，这种机制似乎干扰了LAT促进免疫逃避的能力。 我们建议使用工程重组病毒的体内分析来验证这一假设：(1)测试 潜伏感染的TG是否需要HSV-1 gD与HVEM的结合才能有效地重新激活 以及(2)测试LAT单链RNA是否通过与hvem启动子结合而上调hvem。 对这一假设模型的验证将确定以前未描述的导致HSV-1的机制 并将为识别分子靶标和病毒免疫逃避提供框架 可被利用来更好地管理潜伏的HSV感染的反应。 临床意义及临床意义

Project Summary Following primary ocular HSV-1 infection, the virus replicates in the eye and establishes latency in the trigeminal ganglia (TG). In a latently infected individual, the virus can occasionally reactivate and travel back to the eye causing recurrent disease. Reactivation from latency is the major cause of eye disease. However, the mechanisms underlying this process are not well defined, and currently it is not clear whether reactivation reflects a failure in latency mechanisms or independent mechanisms that break latency. It is well established that the continued expression of the HSV-1 Latency Associated Transcript (LAT) is a characteristic of latency, and this is associated with suppression of apoptosis and regulation of T cell responses to the infected sensory neurons. Recently, we found that in the TG of mice infected with LAT(-) virus, the levels of the HSV-1 receptor, HVEM, but not other HSV-1 receptors was significantly down-regulated. Furthermore, HSV-1 latency and reactivation were reduced significantly in HVEM-/- mice as compared to wild-type mice. Notably, the LAT function in upregulating HVEM mapped to two recently described small non-coding LAT RNAs (sncRNA1 and 2), since HVEM was upregulated following transient transfection with plasmids expressing either small non- coding RNA. In parallel, we have found that viral glycoprotein gD, capable of binding HVEM and triggering its signaling through NF-κB, is expressed at low levels in latently infected TG. Collectively, our preliminary data provide compelling evidence supporting the hypothesis that LAT can enhance latency-reactivation and T-cell exhaustion by upregulating HVEM, which in turn promotes HSV-1 reactivation, possibly by facilitating the binding of gD to HVEM. Although the LAT(-) virus expressing baculovirus inhibitor of apoptosis protein gene (cpIAP) had similar levels of latency as wild-type LAT(+) virus, this recombinant virus did not increase HVEM levels suggesting that this reactivation mechanism does not promote reactivation by regulating responsiveness to apoptosis. Rather, this mechanism appears to interfere with the ability of LAT to promote immune evasion. We propose to test this hypothesis using in vivo analyses of engineered recombinant viruses to: (1) Test whether binding of HSV-1 gD to HVEM is required for efficient reactivation in TG of latently infected mice; and (2) Test whether the LAT sncRNAs upregulate HVEM by binding to the HVEM promoter. Validation of this hypothetical model will identify previously undescribed mechanisms that contribute to HSV-1 reactivation and will provide the framework for identification of molecular targets and viral immune evasion response that could be exploited to better manage latent HSV infection. CLINICAL SIGNIFICANCE AND