外异蛋白（Eda）通过与细胞表面的Eda受体（Edar）结合，激活下游信号通路，发挥相应的生理功能。既往研究致力于探讨EDA基因在胚胎发育中的作用，发现EDA基因突变可导致包括睑板腺在内的多种外胚层组织发育异常，而有关EDA在成年机体中功能的研究甚少。我们的前期研究发现，成体睑板腺组织可以分泌大量Eda蛋白，而角膜和结膜上皮细胞表达其受体。本项目拟建立可诱导的EDA基因条件敲除小鼠以及角膜、结膜上皮特异性EDAR条件敲除小鼠，观察Eda在维持眼表上皮稳态中的作用。同时利用基因表达谱芯片技术检测野生型鼠、EDA基因突变的Tabby鼠、EDA及EDAR条件敲除鼠眼表上皮基因的差异表达，探讨Eda蛋白在眼表上皮细胞发挥作用的分子机制，并应用体外细胞培养加以验证。本项目的开展将阐明Eda蛋白在眼表的生物学功能，揭示眼表稳态维持的新机制，为眼表疾病的病理生理机制和治疗研究开拓新的方向。

Ectodysplasin A (Eda) is a type II transmembrane protein. After binding with cell surface Eda receptor (Edar), downstream signaling pathway of Eda is activated to execute its function. Previous studies focused on the effect of EDA on morphogenesis and found EDA gene mutation resulted in developmental abnormity of various ectodermal tissues including Meibomian gland. However, the function of EDA during adult stage is largely unknown. In our recent study, we found Meibomian gland can produce Eda protein in adult stage, while corneal and conjunctival epithelial cells express Edar. Therefore, it is reasonable to hypothesize that Eda may play certain roles after secreting into tear fluid. In this project, we will generate inducible conditional EDA gene knockout mice and corneal/conjunctival epithelial specific EDAR conditional knockout mice, and observe the function of EDA-EDAR signaling pathway on the homeostasis of ocular surface epithelium. To further illustrate the molecular mechanism of Eda on the ocular surface epithelium, we will investigate the gene expression difference in the ocular surface epithelium among wild type mice, EDA mutant Tabby mice, EDA conditional knockout mice and EDAR conditional knockout mice using gene array technique. The mechanism will be further confirmed in ex vivo cultured mouse and human corneal/conjunctival epithelial cells. Implementation of this project will help disclose the biological function of Eda on the ocular surface, unravel new mechanism of ocular surface homeostasis, and shed new light on the pathophysiological mechanism and treatment of ocular surface diseases.