Regulation of Eye Growth and Development by the Lens

描述（由申请人提供）：眼睛不同部位的发育和生长必须完美协调，以便将正确的视觉图像传输到大脑。透镜在一定程度上负责协调眼睛的生长，但我们对潜在机制的知识是不完整的。这个问题将在Astyanax mexicanus中进行研究，Astyanax mexicanus是一种硬骨鱼，由有眼睛的表面居住形式（表面鱼）和盲洞穴居住形式（洞穴鱼）组成。眼原基最初是在洞穴鱼发育过程中形成的，但它们随后停止并退化，导致失明的成年鱼。首先退化的组织是透镜，接着是视网膜。将表面正常的鱼胚胎透镜移植到洞穴鱼视杯中，可以使成年洞穴鱼恢复完整的眼睛。几个基因，包括那些编码抗凋亡蛋白1A-晶体蛋白，热休克蛋白Hsp 901，和中线信号形态发生蛋白音刺猬（shh）的候选人的调节器的洞穴鱼类透镜细胞凋亡。透镜在保护视网膜免于凋亡性细胞死亡以及在角膜和巩膜的正常发育中也是重要的。该项目的总体目标是确定透镜如何通过细胞凋亡而变得功能障碍，以及异常的透镜如何反过来影响眼睛的整体生长和发育。前两个目标集中于导致透镜内细胞凋亡的事件。第一个目的是研究1A-晶体蛋白和1B-晶体蛋白下调在透镜凋亡中的作用。第二个目的是研究hsp 901上调在透镜凋亡中的作用，以及它在shh和1 -晶状体蛋白基因的假定凋亡途径中的存在。后两个目标移动到透镜外部以聚焦于视网膜、角膜和巩膜、其发育依赖于透镜的光学组件以及视网膜色素上皮（RPE），其通常可与透镜协作以保护视网膜免于凋亡。第三个目标是研究视网膜基因，这些基因可能参与控制视网膜生死的途径，以及透镜在负责角膜和巩膜发育的迁移性神经嵴细胞的分化和模式化中的作用。最终目的将确定RPE是否与透镜协作介导视网膜细胞存活。本申请的目的是将联合收割机透镜显微外科操作、细胞和分子标记物的使用、实验性基因过表达和抑制以及遗传分析相结合，以创建缺乏特定光学组件的鱼类品系，该特定光学组件可用于测试眼睛生长协调的假设。这项研究的目的是提供新的见解，如何透镜协调眼睛的生长和失明如何可能导致在这个过程中的缺陷。这将填补我们对正常和异常眼睛发育的理解中的一个主要空白。公共卫生相关性：眼睛不同部位的精确发育协调是将正确的图像传输到大脑所必需的。本研究以盲洞穴鱼为模型，旨在提供有关眼透镜在协调眼睛发育中的作用的新信息。研究结果将为异常的眼睛发育提供深入的见解。

DESCRIPTION (provided by applicant): Development and growth of the diverse parts of the eye must be perfectly coordinated in order to transmit correct visual images to the brain. The lens is responsible in part for coordinating eye growth but our knowledge about the underlying mechanisms is incomplete. This problem will be studied in Astyanax mexicanus, a teleost fish consisting of an eyed surface dwelling form (surface fish) and a blind cave-dwelling form (cavefish). Eye primordia are initially formed during cavefish development but they subsequently arrest and degenerate, resulting in a blind adult. The first tissue to degenerate is the lens, which is followed by the retina. Transplantation of a normal surface fish embryonic lens into a cavefish optic cup can restore a complete eye in adult cavefish. Several genes, including those encoding the anti-apoptotic protein 1A-crystallin, the heat shock protein Hsp901, and the midline signaling morphogen sonic hedgehog (shh) are candidates for regulators of cavefish lens apoptosis. The lens is also important in protecting the retina from apoptotic cell death and in the normal development of the cornea and sclera. The overall goal of this project is to determine how a lens becomes dysfunctional through apoptosis and how an abnormal lens in turn affects overall growth and development of the eye. The first two aims focus on events leading to apoptosis within the lens. The first aim will investigate the role 1A-crystallin and 1B-crystallin downregulation in lens apoptosis. The second aim will examine the role of hsp901 upregulation in lens apoptosis and its existence in a putative apoptotic pathway with shh and 1 -crystallin genes. The last two aims move outside the lens to focus on the retina, cornea and sclera, optic components whose development is dependent on the lens, and the retinal pigment epithelium (RPE), which may normally cooperate with the lens to protect the retina from apoptosis. The third aim investigates retinal genes that are potentially involved in the pathway controlling life or death of the retina, and the role of the lens in the differentiation and patterning of migratory neural crest cells responsible for cornea and sclera development. The final aim will determine if the RPE collaborates with the lens in mediating retinal cell survival. The aims of this application will combine lens microsurgical manipulations, the use of cellular and molecular markers, experimental gene overexpression and inhibition, and genetic analysis to create fish strains deficient in specific optic components that can be used to test hypothesis of eye growth coordination. This research is designed to provide new insights into how the lens coordinates eye growth and how blindness can result from defects in this process. This will fill a major gap in our understanding of both normal and abnormal eye development. PUBLIC HEALTH RELEVANCE: Precise developmental coordination of the different parts of the eye is required to transmit a correct image to the brain. Using the blind cavefish as a model, this study is designed to provide new information about the role of the ocular lens in coordinating eye development. The results will provide insights into abnormal eye development.