Intersection of HSV latency and reactivation with the neuronal apoptotic pathway

描述（由申请人提供）：单纯疱疹病毒（HSV）以潜伏性神经元感染的形式持续宿主的一生。重要的是，病毒的周期性再活化导致显著的发病率和死亡率，特别是在免疫功能低下的宿主中。然而，允许病毒持续存在及其再激活的神经元和分子事件的独特特征尚不清楚。到目前为止，理解病毒与神经元相互作用的障碍是i）体外潜伏期模型的有限使用和ii）原代神经元中基因操作技术的挑战。已发现交感神经元的感染重演体内HSV潜伏期。因此，在这个项目中，我将使用交感神经元和最先进的技术来检查病毒基因的功能，并在神经元中的分子和细胞水平上的病毒再激活的机制。潜伏相关转录本（LAT）编码一个非编码RNA家族，是潜伏期内唯一高水平表达的病毒基因产物。在目标1中，我将测试LAT表达抑制细胞凋亡并促进受感染神经元存活的假设，从而允许长期病毒持续存在并增强再激活。LAT表达质粒将通过显微注射引入神经元中。还将确定LAT保护神经元免受细胞凋亡的不同触发的能力以及LAT发挥保护作用的机制。在目标2中，我将重点研究神经元内触发HSV再激活的信号事件。当交感神经元被剥夺神经生长因子（NGF）时，触发病毒再激活。由于神经生长因子剥夺激活神经元凋亡，我将确定神经生长因子剥夺后，激活HSV裂解基因的表达，使病毒重新激活的凋亡途径中的关键事件。了解HSV潜伏期如何维持在细胞水平，以及了解神经元内触发其再激活的关键事件，对于确定预防HSV从神经元再激活的新型治疗剂的潜在靶点至关重要。

DESCRIPTION (provided by applicant): Herpes simplex virus (HSV) persists for the lifetime of the host in the form of a latent infection of neurons. Importantly, periodic reactivation of the vius results in significant morbidity and mortality, particularly in the immunocompromised host. However, the unique characteristics of neurons and molecular events that allow viral persistence and its reactivation are not understood. So far, obstacles to understanding the interaction of the virus with neurons have been i) the limited use of an in vitro model of latency and ii) challenges in gene manipulation techniques in primary neurons. Infection of sympathetic neurons has been found to recapitulate HSV latency in vivo. Therefore, in this project I will use sympathetic neurons and state-of-art techniques to examine viral gene function, and the mechanism of viral reactivation at the molecular and cellular level in neurons. The latency-associated transcript (LAT) encodes a family of non-coding RNAs and is the only viral gene product expressed to high levels during latency. In Aim 1, I will test the hypothesis that LAT expression inhibits apoptosis and promotes survival of infected neurons, thus allowing for long-term viral persistence and enhanced reactivation. LAT expressing plasmids will be introduced into neurons by microinjection. The ability of the LAT to protect neurons against different triggers of apoptosis and the mechanism by which the LAT exerts protection will also be determined. In Aim 2, I will focus on examining the signaling events within neurons that trigger HSV reactivation. Viral reactivation is triggered when sympathetic neurons are deprived of nerve growth factor (NGF). Since NGF deprivation activates apoptosis in neurons, I will identify the key event in the apoptotic pathway after NGF deprivation that activates the expression of HSV lytic genes to allow viral reactivation. An understanding of how HSV latency is maintained at the cellular level and knowledge of key events within neurons that trigger its reactivation are critica to identify potential targets for novel therapeutics that prevent HSV reactivation from neurons.