Role of HSV Induced RNA Degradation in Pathogenesis

描述（由申请人提供）：单纯疱疹病毒（HSV）角膜炎是发达国家非创伤性失明的主要原因，在美国每年有超过20万例病例。HSV可在人类中引起多种眼部疾病，范围从自限性树突状上皮角膜炎、结膜炎和睑缘炎到坏死性基质角膜炎。此外，HSV通常引起唇疱疹、生殖器溃疡，并且是病毒性脑炎的主要原因。HSV和其他嗜神经性疱疹病毒的生命周期的特征在于在外周部位如角膜和皮肤的感染的裂解期，在此期间所有病毒基因都表达，以及在神经元中的感染的潜伏期，在此期间基因表达极其有限。潜伏期代表病毒的终身来源，其可以周期性地重新激活，引起严重的眼部和其他粘膜皮肤损伤，并且建立终身潜伏期的能力使得HSV对治愈具有抗性。 嗜神经性疱疹病毒的一个标志是它们能够迅速关闭它们感染的细胞中的大分子合成。对于HSV 1型（HSV-1）和HSV-2，负责这种关闭的基因是UL 41基因的产物，称为病毒体宿主关闭蛋白或vhs。所有嗜神经性疱疹病毒都有UL 41基因的同源物，尽管在神经元中建立潜伏期的病毒之间这种基因保守的原因尚不清楚。我们先前资助的研究表明，vhs活性在眼睛的感染和损伤、眼周疾病的发展和潜伏期的建立中起着至关重要的作用。我们已经定义了一个结构域的vhs是至关重要的，它与VP 16的相互作用，从而调节其包装和活动。我们还表明VHS活性可以改变对HSV免疫应答的大小。此外，我们还发现缺乏vhs的病毒是预防复发性疱疹感染的有效疫苗。这些成果完全符合NEI角膜疾病计划的研究目标。 这个提议的目的是建立在我们以前的发现和进一步研究多功能vhs蛋白的作用机制及其对发病机制和眼部疾病的影响。我们解决的假设是，VHS有助于使HSV干扰素耐药，通过其改变干扰素诱导的激酶PKR的活性的能力。此外，我们还检验了这样一个假设：vhs活性通过控制抗原呈递改变了病毒感染细胞的识别，从而形成了有利于病毒的适应性免疫反应。最后，我们将确定vhs的结构域，这些结构域对于单纯疱疹病毒与神经元的相互作用非常重要，是病毒的潜伏位点，并确定单纯疱疹病毒和vhs如何改变神经元中的基因表达模式。我们的理由是，更好地定义的机制和域的vhs功能将提供针对HSV眼病的治疗干预的目标，以及帮助HSV疫苗的设计。

DESCRIPTION (provided by applicant): Herpes simplex virus (HSV) keratitis is a leading cause of non-traumatic blindness in developed countries, with more than 200,000 cases per year in the USA. HSV can cause a variety of ocular diseases in humans ranging from self-limiting dendritic epithelial keratitis, conjunctivitis, and blepharitis to necrotizing stromal keratitis. In addition, HSV commonly causes cold sores, genital sores, and is a leading cause of viral encephalitis. The life cycles of HSV and other neurotropic herpesviruses are characterized by a lytic phase of infection at peripheral sites such as the cornea and skin during which all virus genes are expressed, and a latent phase of infection in neurons, during which gene expression is extremely limited. Latency represents a lifelong source of virus which can reactivate periodically causing severe ocular and other mucocutaneous damage, and the ability to establish lifelong latency renders HSV resistant to cure. One hallmark of the neurotropic herpesviruses is their ability to rapidly shut off macromolecular synthesis in the cells that they infect. For HSV type 1 (HSV-1) and HSV-2 the gene responsible for this shutoff is the product of the UL41 gene known as the virion host shutoff protein or vhs. All of the neurotropic herpesviruses have a homolog of the UL41 gene, although the reason for this gene conservation among viruses that establish latency in neurons is not known. Our previously funded studies have shown that vhs activity plays an essential role in infection and damage of the eye, in the development of periocular disease, and in the establishment of latency. We have defined a domain of vhs that is critical for its interaction with VP16 and thereby regulates both its the packaging and activity. We have also shown that vhs activity can alter that magnitude of immune responses to HSV. In addition we have shown that viruses deficient in vhs are effective vaccines for the prevention of recurrent herpetic infections. These accomplishments are in complete accordance with the stated research goals of the Corneal Diseases Program of the NEI. The objectives of this proposal are to build upon our previous findings and further investigate the mechanisms of action of the multifunctional vhs protein and its impact upon pathogenesis and ocular disease. We address the hypothesis is that vhs helps render HSV resistant to interferon through its ability to alter the activity of the interferon-induced kinase PKR. In addition, we test the hypothesis that vhs activity alters the recognition of virus-infected cells through control of antigen presentation, thereby shaping the adaptive immune response in favor of the virus. Finally we will identify the domains of vhs, which are important for the interaction of HSV with neurons, the site of latency for the virus, and identify how HSV and vhs alter gene expression patterns in neurons. We reason that a better definition of the mechanisms and domains of vhs function will provide targets for therapeutic intervention against HSV ocular disease, as well as aiding in the design of HSV vaccines.