肥大细胞触发抗角膜真菌感染的细胞和分子机制

The current study shows that mast cells (MCs) are the first line cells of immune defense for fighting infection. Mast cells exert important influence on both innate and adaptive immune response. Our preliminary study found that: 1) there were a lot of MCs around the blood vessels of the limbus; 2)MCs expressed pattern recognition receptor of fungal-specific molecule, such as Dectin-2; 3) in organ culture model and in vivo models, MCs were with the great performance of the degranulation response to fungal polysaccharide stimulation and corneal fungal infection; 4)local APCs had ability for phagocytizing the fungal antigens. Based on these prelimnary data, the project aims at disolving the following important issues: 1) Phenotypic analysis of mast cells around the limbal vessels; 2)Degranulation process and the corresponding release of molecular dynamics; 3) The effect on vascular permeability, vessel dilation and endothelial adhesion molecule expression; 4) The effect on neutrophil migration to the infected cornea as well as platelet adhesion and recruitment on the vascular wall; 5) Effects on the adaptive immune response process; 6) The direct killing effect on fungi. Through observation and data analysis on these issues, we try to propose new theoretical models and to develop new pathways or routes to understand mechanisms of anti-fungal infection from local mast cells. Our final target is to provide some new theories and new technologies for the ultimate control of corneal fungal infection.

目前的研究表明，肥大细胞（MCs）属抗感染一线免疫细胞，对初始免疫和适应性免疫都具重要影响。我们的初步研究发现，正常角巩缘血管周围存在大量MCs；MCs表达真菌特异性的模式识别受体Dectin-2；在器官培养和动物模型，MCs针对真菌有效成分的刺激和活体感染表现为脱颗粒反应；局部的APCs具有吞噬真菌抗原的能力。本项目旨在此基础上对MCs的下述重要问题进行研究：1)角膜缘血管周围MCs的表型分析；2）脱颗粒过程及其相应的释放分子动力学；3）对血管通透性、扩张状态和内皮粘附分子表达的影响；4）对嗜中性粒细胞向感染角膜以及血小板在血管壁粘附和募集的影响；5）对适应性免疫应答特异性免疫触发过程的影响；6）对真菌的直接杀伤作用。 通过对上述问题的研究，达到对MCs触发角膜抗真菌感染机制的理解，并为最终控制角膜真菌感染提供新的治疗措施和有意义的理论依据。

真菌性角膜炎是一种严重的致盲性眼病。前期研究表明MCs（Mast cell，MCs）分布于角巩膜缘周围，MCs在真菌特定成分的刺激下出现脱颗粒反应。在前期研究基础上，本项目进行了以下研究：1）通过活体小鼠角膜细胞形态3D重建，了解了正常小鼠角膜细胞的生理学特征，并在真菌菌丝荧光标记的基础上建立可活体动态观察的真菌性角膜炎小鼠模型；2）确定了MCs在角膜的定位以及与血管及神经的关系；3）了解了角膜缘MCs的亚型种类以及分布；4）了解了MCs脱颗粒对血管通透性以及血管扩张的影响；5）分析了MCs对细胞间粘附分子表达的影响；6）确定了MCs激活对中性粒细胞向角膜感染部位募集的影响；7）通过不同的技术方法，确定了其对真菌的间接杀菌作用。.通过以上研究，阐明了MCs仅存在于正常角膜角巩膜缘，且分布于血管、神经周围，属于结缔组织亚型；角膜感染真菌引起角膜缘部位MCs激活，角膜真菌感染2周后MCs亚型发生转换，由结缔组织型转化为黏膜型。MCs激活引起角膜缘血管扩张、血管通透性增加，角膜组织ICAM-1表达增加，促进中性粒细胞向感染部位募集，增加对真菌的杀灭，最终减少角膜组织破坏。通过上述研究，理解了MCs角膜抗真菌感染机制，明确了MCs在角膜抗真菌感染中的作用机制，并为最终控制真菌性角膜炎提供新的防治思路和理论依据