CONTROL OF CORNEAL ENDOTHELIUM DEVELOPMENT IN THE MOUSE

本研究的目的是确定Mf 1，前额/翼状螺旋转录因子，在哺乳动物眼角膜的发展中的作用。我们先前已经证明，在缺乏功能性Mf 1基因（通过同源重组-Mf 1/lacZ-或作为自发突变-Mf 1/Ch的结果产生）的小鼠胚胎中，角膜内皮不能从胚胎角膜间充质分化。这伴随着许多其他早期发育异常，包括前房形成失败、虹膜营养不良和小梁网异常（Kidson等，1999，附录）。这些突变体不能形成角膜内皮，因此为研究角膜内皮在体内的正常发育提供了一个理想的系统，对此知之甚少。小鼠Mf 1基因的人类同源物（称为FKHL/FREAC 3）最近被两个研究小组克隆。该基因中的显性突变已被证明与遗传性眼前节缺陷相关，包括虹膜发育不全、前角和小梁网发育不全、角膜混浊和青少年发作先天性青光眼的风险增加（Axenomy-Rieger Anomaly，米尔斯等人，1998; Nishimura等人，1998）。此外，已报告人类的几种角膜遗传性疾病。例如，先天性遗传性内皮营养不良（一种常染色体显性或隐性的病症）与内皮缺失、基质增厚和角膜混浊相关（Mullany et al，1995; Kirkness et al，1987）。因此，拟议的研究将导致更好地了解与角膜内皮衰竭相关的人眼缺陷，包括青光眼和角膜内皮营养不良。将检验Mf 1在角膜间充质中作为来自胚胎透镜分泌的尚未鉴定的因子的下游信号通路的一部分起作用的假设。将使用的技术将包括正常和突变角膜间充质的体外培养和分化、与胚胎透镜共培养、添加生长因子和筛选Mf 1调节的基因。

The goal of this study is to define the role of Mf1, a forehead/winged helix transcription factor, in the development of the cornea of the mammalian eye. We have previously shown that in mouse embryos lacking a functional Mf1 gene (generated either by homologous recombination-Mf1/lacZ-or as a result of spontaneous mutation-Mf1/Ch) the corneal endothelium fails to differentiate from the embryonic corneal mesenchyme. This is accompanied by a number of other eve developmental abnormalities, including failure of anterior chamber formation, iris dystrophy, and abnormalities of the trabecular meshwork (Kidson et al, 1999, Appendix). The failure to form a corneal endothelium in these mutants thus provides an ideal system for investigate the normal development of the corneal endothelium in vivo, about which little is known. The human homologue of the mouse Mf1 gene (known as FKHL/FREAC3) has recently been cloned by two groups. Dominant mutations in this gene have been shown to be associated with inherited anterior segment defects, including hypoplasia of the iris, dysgenesis of the anterior angle and trabecular meshwork, corneal opacity and increased risk of juvenile onset congenital glaucoma (Axenfeld-Rieger Anomaly, Mears et al, 1998: Nishimura et al, 1998). In addition, several inherited disorders of the cornea have been reported to humans. For example, congenital hereditary endothelial dystrophy, a condition that can be either autosomal dominant or recessive, is associated with absence of the endothelium, thickening of the stroma and corneal opacity (Mullany et al, 1995: Kirkness et al, 1987). Thus, the proposed studies will lead to a better understanding of human eye defects associated with corneal endothelium failure, including glaucoma and corneal endothelial dystrophy. The hypothesis will be tested that Mf1 functions in the corneal mesenchyme as part of the downstream signaling pathway from as yet unidentified factors secreted by the embryonic lens. The techniques to be used will include in vitro culture and differentiation of normal and mutant corneal mesenchyme, co-culture with embryonic lens, addition of growth factors, and screening for Mf1 regulated genes.