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)，一种不同类型的骨髓源性细胞，在连接先天性免疫反应和获得性免疫反应中发挥重要作用。PDC通过Toll样受体识别病毒，以及它们产生大量I型干扰素(IFN)的能力，在抵御病毒感染的第一道防线中发挥着关键作用。在初步研究中，我们在角膜中发现了一种新的常驻PDC群体。体内PDC耗竭的初步研究表明，PDC是角膜中干扰素-α的主要来源，在单纯疱疹病毒性角膜炎(HSK)的宿主防御中起到保护作用。因此，我们的结果表明，PDC在对抗病毒性角膜炎的同时，在保护视力方面是关键参与者。识别PDC在HSK中的特定功能，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，为了在不影响保护性免疫所需的白细胞的情况下抑制驱动疾病的细胞亚群，确定器官和细胞特有的分子迁移机制是至关重要的。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，带有荧光PDC和荧光病毒，并将在活动物中以亚细胞分辨率显示PDC和病毒，使我们能够研究它们与周围细胞的相互作用。在前期工作的基础上，血管黏附分子和趋化因子的器官特异性组合上调调节PDC和T细胞向角膜的募集，以及随后PDC在炎症和感染中从角膜迁移。我们进一步假设PDC通过局部角膜干扰素？？对HSK的角膜具有保护作用。和肿瘤坏死因子-？在HSK中激活后，它们产生并迁移到DLN的不同区域，在那里它们通过干扰素-？介导CD4+T细胞向T调节细胞或T辅助细胞(Th)17细胞的分化途径。和IL-6的产生。将研究PDC以调查引导他们到达正常和发炎的角膜的交通信号灯，并将用于解决以下两个具体目标：1)目的：1.研究角膜PDC的特性，分析炎症过程中PDC募集和外流的分子机制。描述角膜PDC的特征，并剖析炎症过程中调节其募集和外流的分子机制。这些细胞进入和离开角膜的关键途径的识别将为炎症性、感染性、同种异体免疫和自身免疫性疾病的药物干预提供新的和高度特异的分子靶点。在过去的几十年里，眼科领域几乎没有出现有效的抗炎药物，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少视力障碍，提高生产率，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.