Corneal neuropeptides and herpetic stromal keratitis

描述（由申请人提供）：角膜感染单纯疱疹病毒-1 （HSV-1）导致疱疹性基质角膜炎（HSK），是世界范围内感染性角膜失明的主要原因。尽管在了解HSK发病机制方面进行了深入的研究并取得了实质性进展，但这种疾病的治疗仍然具有挑战性。一个重要的障碍是我们对丰富的角膜神经纤维分泌的神经肽在HSK病变发展中的作用了解不足。缺乏这方面的知识是一个重要的问题，因为神经肽是众所周知的调节炎症和组织修复。本应用的目的是确定眼部HSV-1感染后角膜中是什么调节P物质（SP）神经肽水平，以及SP如何与其受体NK1R相互作用控制病毒载量并影响HSK病变的发展。我们将通过使用SP-/-和NK1R-/-小鼠在小鼠模型中解决这些问题。我们最近报道，在没有复制病毒（临床期）的情况下，阻断SP-NK1R相互作用可显著减少HSK病变的发展。然而，正如在SP- /-和NK1R-/-小鼠中所注意到的那样，在角膜活跃病毒复制期间（临床前阶段）缺乏SP-NK1R相互作用会增强HSK病变的严重程度。我们的初步结果显示，在NK1R-/-小鼠中，病毒清除延迟，表皮生长因子（EGF）水平降低，EGF是一种角膜伤口愈合因子。根据我们的初步结果，我们假设SP是由巨噬细胞和角膜神经在HSV-1感染的角膜中产生的，它可以促进角膜组织修复，调节参与病毒清除的先天免疫细胞的涌入、存活和功能。因此，在活跃的病毒复制过程中增强SP介导的作用应该可以减少严重HSK病变的发生。为了解决我们的假设，提出了三个目标。在目的1中，我们将通过实验分别确定角膜巨噬细胞和感觉神经元在HSK临床前和临床期间对HSV-1感染角膜中SP肽水平的调节作用。在目的2中，将进行实验以确定SP-NK1R相互作用是否通过促进HSV-1感染角膜中的树突状细胞（dc）、炎症单核细胞（IM）和自然杀伤细胞（NK）细胞的迁移、存活和功能来调节角膜中的病毒载量。在目标3中，我们将确定是否通过单独局部应用EGF或联合结膜下施用SP来增强活跃病毒复制期间SP介导的效应，调节严重HSK病变的发展。这项研究产生的信息可以帮助开发新的药物策略，通过促进病毒清除和角膜组织修复来减少HSV-1诱导的慢性炎症。

DESCRIPTION (provided by applicant): Corneal infection with herpes simplex virus-1 (HSV-1) causes herpetic stromal keratitis (HSK), a leading cause of infection-induced corneal blindness worldwide. Despite intensive research and substantial progress in understanding the pathogenesis of HSK, the management of this condition continues to be challenging. One significant hurdle is our poor understanding of the role of neuropeptides, secreted by abundant corneal nerve fibers, in the development of HSK lesions. Lack of such knowledge is an important problem because neuropeptides are well known to regulate both inflammation and tissue repair. The objective of this application is to determine what regulates substance P (SP) neuropeptide levels in the cornea after ocular HSV-1 infection, and how SP interactions with its receptor NK1R control the viral load and affects the development of HSK lesions. We will approach these questions in a mouse model by using SP-/- and NK1R-/- mice. We recently reported that blocking SP-NK1R interactions in the absence of replicating virus (clinical period) significantly reduced the development of HSK lesions. However, lack of SP-NK1R interactions during active viral replication in the cornea (pre-clinical period), enhances the severity of HSK lesions, as noted in SP- /- and NK1R-/- mice. Our preliminary results showed delayed viral clearance and reduced levels of epidermal growth factor (EGF), a corneal wound healing factor, in NK1R-/- mice. On the basis of our preliminary results, we hypothesize that SP, produced in HSV-1 infected corneas by macrophages and corneal nerves, promotes corneal tissue repair and regulates the influx, survival, and function of innate immune cells involved in viral clearance therefore, enhancing SP-mediated effects during active viral replication should reduce the development of severe HSK lesions. Three aims are proposed to address our hypothesis. In aim 1, experiments will be carried out to determine the role of corneal macrophages and sensory neurons in regulating the levels of SP peptide in HSV-1 infected corneas during the pre-clinical and clinical periods of HSK, respectively. In aim 2, experiments will be carried out t determine whether SP-NK1R interactions regulate viral load in the cornea by promoting the migration, survival, and functions of dendritic cells (DCs), inflammatory monocytes (IM) and natural killer (NK) cells in HSV-1 infected cornea. In aim 3, we will determine whether enhancing SP-mediated effects during the active viral replication period through topical application of EGF alone, or in combination with subconjunctival administration of SP, modulates the development of severe HSK lesions. The information generated by this study could aid in the development of novel pharmaceutical strategies to reduce HSV-1 induced chronic inflammation by promoting viral clearance and corneal tissue repair.