HSV and Host Cell Contributions to Corneal Infection

病毒篡夺宿主细胞的正常细胞生物学以进行病毒复制和传播的能力取决于病毒基因表达和宿主细胞反应。控制病毒侵袭上皮的关键在于了解病毒在宿主细胞内和细胞间传播的机制。我们将重点讨论1型单纯疱疹病毒（HSV）侵入和篡夺角膜上皮细胞机制的机制。关于角膜中HSV感染和传播的调节的现有信息是有限的。然而，很明显，至少涉及三种机制。1)游离病毒可以从远处进入角膜，与宿主细胞膜附着融合进入细胞（病毒融合机制）。2)将病毒粒子从感染细胞转移到偶联的相邻细胞（细胞间扩散机制）采用不同的机制。3)最后，当细胞从一个位置移动到另一个位置时，病毒在受感染细胞内的移动（翻译机制）涉及到一个不太被广泛认识的机制。我们推测病毒包膜糖蛋白和宿主细胞表面受体在HSV在角膜内传播的第一和第二机制中起关键作用，而不是在翻译机制中起关键作用。我们将使用两种小鼠模型系统：第一，原发感染病毒致角膜表面损伤；第二，通过感染的三叉神经节细胞轴突将病毒传递到完整角膜基底表面的复发性疱疹感染模型。利用遗传学、药理学和免疫细胞化学工具，我们将通过对HSV包膜糖蛋白突变的不同敏感性来定义病毒融合和细胞间传播的贡献。病毒感染细胞的易位作用将通过将HSV作为脉冲递送，使用Valacyclovir消除继发性细胞感染来确定。这些体内实验将提供关于HSV在体内鳞状上皮细胞之间转移和宿主细胞连接对损伤反应的基本细胞生物学信息。此外，该结果还将具有显著的临床效益。更好地了解角膜损伤后病毒传播与人类疱疹性角膜炎中由HSV再活化传递到角膜引起的传播之间的差异，将重点关注是否需要不同的策略来治疗初次感染而不是复发性感染。此外，我们的结果将导致鉴定病毒传播所必需的病毒和宿主蛋白，并为设计创新抗病毒药物提供合理的基础。

The ability of a virus to usurp the normal cell biology of a host cell for viral replication and spread depends on both viral gene expression and host cell responses. The key to controlling viral invasion of an epithelium lies in understanding the mechanisms by which virus spreads within and between host cells. We shall focus on mechanisms by which Herpes simplex virus type 1 (HSV) invades and usurps the machinery of corneal epithelial cells. The available information about the regulation of HSV infection and spread in the cornea is limited. However, it is clear that at least three mechanisms are involved. 1) Free virus can enter the cornea from a distance, attach and fuse with a host cell plasma membrane and enter the cell (viral fusion mechanism). 2) A different mechanism is used for transfer of virions from an infected cell to coupled adjacent cells (cell-to-cell spread mechanism). 3) Finally, a less widely recognized mechanism involves the movement of virus in an infected cell as the cell moves from one location to another (translational mechanism). We hypothesize that viral envelope glycoproteins and host cell surface receptors play key roles in the spread of HSV in cornea in the first and second mechanisms, but not in the translational mechanism. We will use two mouse model systems: first, primary infection with virus delivered to the corneal surface injury; and second, a model of recurrent herpetic infection by viral delivery to the basal surface of the intact cornea via infected trigeminal ganglion cell axons. Using genetic, pharmacological and immunocytochemical tools, we shall define the contributions of viral fusion and cell-to-cell spread by their different sensitivity to mutations in the HSV envelope glycoproteins. The role of translocation of virally infected cells will be determined by delivering HSV as a pulse, using Valacyclovir to eliminate secondary cell infection. These in vivo experiments will provide fundamental, cell biological information about the transfer of HSV between squamous epithelial cells in vivo and the response of host cell junctions to injury. In addition, the results will also have significant clinical benefits. A better understanding of the differences between spread of virus after corneal injury and of the spread that results from reactivated HSV delivered to the cornea in human herpetic keratitis will focus attention on whether different strategies are required for treatment of initial as opposed to recurrent infections. Moreover, our results will lead to identification of viral and host proteins that are necessary for viral spread and a rational basis for the design of innovative antiviral drugs.