The role of plasmacytoid dendritic cells in corneal immunity

描述（申请人提供）：浆细胞样树突状细胞（pDC）是一种独特类型的骨髓源性细胞，在连接先天性和适应性免疫应答中发挥重要作用。pDC在抵抗病毒感染的第一道防线中是关键的，其通过toll样受体抑制病毒以及它们产生大量I型干扰素（IFN）的能力。在初步研究中，我们发现了角膜中的新的常驻pDC群体。在我们的初步研究中，体内pDC耗竭证明pDC是角膜中IFN-α的主要来源，并且在单纯疱疹性角膜炎（HSK）中的宿主防御中起保护作用。因此，我们的研究结果表明，pDC是对抗病毒性角膜炎的关键参与者，同时保留视力。鉴定HSK中pDC的特异性功能并了解pDC和T细胞在角膜中迁移的关键途径可能为通过免疫治疗进行药物干预提供新的分子靶点。然而，定义器官和细胞特异性分子迁移机制是至关重要的，以抑制驱动疾病的细胞亚群，而不影响保护性免疫所需的白细胞。为了解决这些问题，我们开发了一种新的多光子活体显微镜（MP-IVM）模型来研究活体小鼠完整角膜中的pDC。这种成像方法使用转基因小鼠，荧光pDC和荧光病毒，并将在活体动物中以亚细胞分辨率可视化pDC和病毒，使我们能够研究它们与周围细胞的相互作用。基于初步工作以及血管粘附分子和趋化因子的器官特异性组合的上调调节pDC和T细胞向角膜的募集以及随后的炎症和感染中pDC从角膜的迁移。我们进一步假设pDC通过局部角膜IFN-γ对HSK角膜有保护作用。TNF-？生产和迁移到不同地区的dLN激活后，在HSK，在那里他们介导的分化途径的CD 4 + T细胞的T调节或T辅助细胞（Th）17细胞通过IFN-？和IL-6的产生。pDC将被研究以调查引导他们到正常和发炎角膜的交通信号，并将用于解决以下两个具体目标：1.表征角膜pDC并剖析炎症期间介导其募集和流出的分子机制; 2.）表征角膜pDC并剖析炎症期间介导其募集和流出的分子机制。这些细胞迁移到角膜和从角膜的关键途径的鉴定将提供新的和高度特异性的分子靶点，用于炎症，感染，同种异体免疫和自身免疫性疾病的药理学干预。在过去的几十年中，在眼科领域几乎没有出现有效的抗炎药物，并且迫切需要新药。HSK是导致失明的主要原因。HSK的有效治疗将显著减轻视力损害，提高生产力，并减轻治疗HSK的负担。

DESCRIPTION (provided by applicant): Plasmacytoid dendritic cells (pDC), a distinct type of bone marrow-derived cell, play an important role in linking innate and adaptive immune responses. pDC are pivotal in the first line of defense against viral infections through recognitio of viruses by toll-like receptors as well as their ability to produce large amounts of type I interferons (IFN). In preliminary studies, we have discovered a novel population of resident pDC in the cornea. In vivo pDC depletion in our preliminary studies demonstrate that pDC are the major source of IFN-a in the cornea and play a protective role in the host defense in herpes simplex keratitis (HSK). Thus our results suggest that pDC are key participants in fighting viral keratitis, while preserving vision. Identifying specific functions of pDC in HSK and understanding the critical pathways of pDC and T cell migration in the cornea may provide new molecular targets for pharmacological intervention through immunotherapy. However, defining organ- and cell-specific molecular migratory mechanisms is critical, in order to inhibit cell subsets driving disease, without affecting leukocytes required for protective immunity. To address these questions, we have developed a new multiphoton intravital microscopy (MP-IVM) model to study pDC in intact corneas of living mice. This imaging approach uses transgenic mice, with fluorescent pDC, and fluorescent viruses, and will visualize pDC and viruses at subcellular resolution in living animals, allowing us to study their interaction with surrounding cells. Based on preliminary work and that up-regulation of organ-specific combination of vascular adhesion molecules and chemokines regulate pDC and T cell recruitment to the cornea and subsequent migration of pDC from the cornea in inflammation and infection. We further hypothesize that pDC are protective to the cornea in HSK through local corneal IFN-? and TNF-? production and migrate to distinct areas of the dLN after activation in HSK, where they mediate differentiation pathways of CD4+ T cells to T regulatory or T helper (Th)17 cells through IFN-? and IL-6 production. pDC will be studied to investigate the traffic signals that guide them to normal and inflamed corneas and will be used to address the following two specific aims: 1.) To characterize corneal pDC and dissect the molecular mechanisms that mediate their recruitment and egress during inflammation; 2.) To characterize corneal pDC and dissect the molecular mechanisms that mediate their recruitment and egress during inflammation. Identification of these critical pathways of cell migration to and from the cornea will provide new and highly specific molecular targets for pharmacological intervention in inflammatory, infectious, alloimmune and autoimmune diseases. Few effective anti-inflammatory drugs have emerged over the last decades in the ophthalmic field and an urgent need for new drugs exists. HSK is a leading cause of blindness. Effective therapy for HSK would significantly reduce visual impairment, increase productivity, and reduce the burden of treating HSK.