Corneal neuropeptides and herpetic stromal keratitis

描述(由申请人提供)：单纯疱疹病毒1型(HSV-1)感染角膜会导致疱疹间质角膜炎(HSK)，这是全球感染导致角膜失明的主要原因。尽管对HSK的发病机制进行了深入的研究并取得了实质性的进展，但对这种情况的管理仍然具有挑战性。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病变发展中的作用缺乏了解。缺乏这样的知识是一个重要的问题，因为众所周知神经肽既可以调节炎症，也可以调节组织修复。本应用的目的是确定眼部HSV-1感染后角膜中P物质(SP)神经肽水平的调节因素，以及SP与其受体NK1R的相互作用如何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-/-小鼠在小鼠模型中探讨这些问题。我们最近报道，在没有复制病毒的情况下(临床期)阻断SP-NK1R相互作用显著减少HSK病变的发展。然而，如在SP-/-和NK1R-/-小鼠中注意到的那样，在角膜中活跃的病毒复制过程中(临床前期)缺乏SP-NK1R相互作用会增加HSK损害的严重程度。我们的初步结果显示，在NK1R-/-小鼠中，病毒清除延迟，角膜伤口愈合因子-表皮生长因子(EGF)水平降低。根据我们的初步结果，我们推测，在HSV-1感染的角膜中，由巨噬细胞和角膜神经产生的SP促进了角膜组织的修复，并调节了参与病毒清除的天然免疫细胞的流入、存活和功能。因此，在病毒的活跃复制过程中，加强SP的介导作用应该可以减少严重HSK病变的发生。我们提出了三个目标来解释我们的假设。目的1研究HSK前期和临床期角膜巨噬细胞和感觉神经元在HSV-1感染角膜中对SP多肽水平的调节作用。目的2研究SP-NK1R相互作用是否通过促进HSV-1感染角膜中树突状细胞(DC)、炎性单核细胞(IM)和自然杀伤(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，我们将确定在活跃的病毒复制期间，通过单独局部应用EGF或联合结膜下应用SP来增强SP介导的作用，是否调节严重HSK病变的发展。这项研究产生的信息可能有助于开发新的药物策略，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.