Mechanisms of development of curved refractive surfaces

角膜曲率异常与包括近视在内的多种视觉缺陷有关， 远视、圆锥角膜和散光。然而，产生的发育机制 适当的角膜曲率还不是很清楚。这项提议将使用果蝇角膜晶状体作为 一个简单的模型系统来研究曲率的发展，并将测试它是否有共同之处 哺乳动物角膜的分子和发育机制。该项目以数据为基础 表明保守的Blimp-1转录因子对果蝇的外曲是必需的 角膜晶状体，它作用于外周第二级和第三级色素细胞，而不是中央 分泌大量细胞外角膜晶状体材料的细胞。相似函数的可能性 对于小鼠，Blimp1/Prdm1是由于其在角膜缘上皮细胞中的富集性而被认为是 成人角膜。第一个目标是研究控制果蝇角膜晶状体的转录网络 发展。在没有Blimp-1的情况下，C/EBP同源慢边界细胞(SLBO)高度 上调和SLBO的过度表达，就像Blimp-1的缺失一样，会导致外部平坦的角膜晶状体。这个 SLBO抑制是Blimp-1的主要功能的假设将通过使这两个基因失活来检验 同时。这一目标还将识别Blimp-1下游的其他关键转录因子，并将 测试Blimp-1在眼睛中的瞬时激素调节表达是否对颞叶 对分化的控制。第二个目标将确定外周色素细胞如何对 角膜镜片曲率。将研究两种可能性：色素细胞分泌蛋白质成分 其定位于周边角膜晶状体并使其具有与中央区域不同的结构特性， 而通过附着在色素细胞上的角膜晶状体所受的力控制着 曲率。第三个目标将探索昆虫和哺乳动物角膜之间可能的保护。 结构。CG43333，一个在果蝇视网膜中被Blimp-1抑制的基因，在 Blimp-1突变体的异常角膜晶状体表型与转化生长因子β-1同源- 诱导蛋白，人类角膜营养不良的常见突变靶点。疾病突变的影响 在CG43333上，将检查积累和本地化，以确定它们是否再现了特征 角膜营养不良。人类角膜上皮细胞和角膜类器官将被用来确定 人类BLIMP1与果蝇Blimp-1在角膜中有共同的靶基因。最后， 将检测Blimp1在小鼠角膜中的发育表达模式，以确定它是否 与角膜曲率的作用是一致的。这些实验将阐明曲率是如何被赋予的 屈光结构主要由细胞外基质组成，并将建立果蝇角膜 晶状体作为了解角膜发育和疾病的模型。

Abnormal curvature of the cornea is associated with multiple visual defects including myopia, hyperopia, keratoconus and astigmatism. However, the developmental mechanisms that generate appropriate corneal curvature are not well understood. This proposal will use the Drosophila corneal lens as a simple model system to investigate the development of curvature, and will test whether it shares common molecular and developmental mechanisms with the mammalian cornea. The project is based on data showing that the conserved Blimp-1 transcription factor is essential for external curvature of the Drosophila corneal lens, and that it acts in the peripheral secondary and tertiary pigment cells rather than in the central cells that secrete the bulk of the extracellular corneal lens material. The possibility of an analogous function for mouse Blimp1/Prdm1 is suggested by its enrichment in the limbal epithelial cells at the periphery of the adult cornea. The first aim will investigate the transcriptional network that controls Drosophila corneal lens development. In the absence of Blimp-1, the C/EBP homologue Slow border cells (Slbo) is highly upregulated, and Slbo overexpression, like loss of Blimp-1, results in externally flat corneal lenses. The hypothesis that slbo repression is a major function of Blimp-1 will be tested by inactivating both genes simultaneously. This aim will also identify other critical transcription factors downstream of Blimp-1, and will test whether transient hormonally regulated expression of Blimp-1 in the eye is important for the temporal control of differentiation. The second aim will determine how the peripheral pigment cells contribute to corneal lens curvature. Two possibilities will be investigated: that pigment cells secrete protein components that localize to the peripheral corneal lens and give it structural properties distinct from the central region, and that force exerted on the corneal lens through its attachments to pigment cells controls the pattern of curvature. The third aim will explore possible conservation between insect and mammalian corneal structures. CG43333, a gene that is repressed by Blimp-1 in the Drosophila retina and contributes to the abnormal corneal lens phenotype of Blimp-1 mutants, is homologous to Transforming growth factor beta- induced protein, a frequent target of mutation in human corneal dystrophies. The effect of disease mutations on CG43333 accumulation and localization will be examined to determine whether they reproduce features of corneal dystrophy. Human corneal epithelial cells and corneal organoids will be used to establish whether human BLIMP1 has target genes in common with Drosophila Blimp-1 in the cornea. Finally, the developmental expression pattern of Blimp1 in the mouse cornea will be examined to determine whether it is consistent with a role in corneal curvature. These experiments will elucidate how curvature is imparted to refractive structures composed primarily of extracellular matrix, and will establish the Drosophila corneal lens as a model to understand corneal development and disease.