调控眼胚裂融合的细胞和分子机理的研究

Optic fissure is a transient opening on the ventral side of the developing optic cup, which will close eventually. The failure in closing the optic fissure leads to coloboma, a congenital eye disease that disrupts children's vision significantly, even cause blindness at the most severe situation. At present, the cellular and molecular mechanism governing the optic fissure closure is far from clear, which makes the study of the etiology of coloboma difficult. Through analysis of the detailed cellular process of the optic fissure closure in mice, we noticed that optic fissure closure is a precisely controlled morphogenesis process that involves significant remodeling of cell-cell and cell-ECM (extracellular matrix)interaction. However, currently we know nothing about the matrix metalloproteinase and cytoskeleton regulatory proteins involved in these cell-cell and cell-ECM remodeling, as well as the regulatory mechanisms that control the expression and function of these proteins. In this proposed study, we will start with searching for genes that are specifically expressed in the optic cup progenitor cells surrounding the optic fissure, combine the transcriptome analysis, cell biology, molecular biology, mice and zebrafish genetics to search for genes that execute the fusion process of the optic fissure, and study how they are regulated. Our study will reveal the cellular and molecular mechanisms governing the optic fissure closure, which are the bases for developing strategies to diagnose and treat coloboma.

眼胚裂（optic fissure）是视网膜形态发生过程中形成的临时性裂隙，后将完全融合。眼胚裂融合失败将在视网膜腹侧留下永久性裂隙，被称为视网膜缺损（coloboma）。视网膜缺损是导致儿童视力障碍，甚至失明的严重先天性遗传眼病。当前，对眼胚裂融合的细胞和分子机理的研究尚肤浅，这使得研究视网膜缺损的病因学变得困难。我们的前期工作提示眼胚裂融合是时空上精确调控的形态发生过程，涉及到融合部位广泛的细胞-细胞和细胞-细胞外基质的重组。然而，我们对执行眼胚裂融合组织重组程序的基质蛋白酶和细胞骨架调控蛋白，以及调控它们时空精确表达和功能的机制一无所知。在本项目中，我们将从分析眼胚裂两侧视杯组织中高度特异性表达的基因入手，结合转录基因组学，细胞生物学，分子生物学，小鼠和斑马鱼遗传学等手段，寻找执行眼胚裂融合的功能基因，深入探讨调控眼胚裂融合的细胞和分子机理，为视网膜缺损的诊断和治疗提供理论基础

眼胚裂是视网膜形态发生过程中形成的临时性裂隙，后将完全融合。眼胚裂融合失败将导致严重的儿童致盲性眼病-眼缺损。为了研究眼胚裂融合的分子机制，在本项目中我们运用基因芯片技术比较了眼胚裂周围视杯组织与鼻侧，颞侧视杯组织的转录组，发现眼胚裂周围视杯组织表达非常独特的转录组。从眼胚裂特异性表达的诸多基因中，我们选取了高度特异性表达的三个基因进行功能研究。我们的研究结果表明：Adamts16-一个细胞外基质金属蛋白酶，通过调控细胞外基底膜的降解和调控FGF信号通路表达来调控眼胚裂的融合；Afap1l2-一个细胞骨架调控蛋白，通过调控pax2（眼胚裂发育重要的调控转录因子）来调控眼胚裂的融合；Shtn1，一个研究不多的脑部特异性基因，也参与到眼胚裂融合的调控中。此外，Shtn1对于视网膜前体细胞的增殖、分化以及视神经的投射均有重要调控作用。本课题揭示了眼胚裂周围视杯组织独特的转录基因组，并且阐明了眼胚裂特异基因对于其融合的重要调控作用及其机制,为人类眼缺损疾病的遗传学研究提供了理论基础。相关的研究结果一篇发表于眼科学基础研究权威杂志Investigative Ophthalmology & Visual Science（IOVS），一篇投稿IOVS，现在修稿中，另有一篇将于近期投稿。