Regulation of Eye Growth and Development by the Lens

描述（申请人提供）：眼睛各部分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。晶状体在一定程度上负责协调眼睛的生长，但我们对其潜在机制的了解尚不完整。这个问题将在Astyanax mexicanus中进行研究，Astyanax mexicanus是一种硬骨鱼，由有眼睛的水面生活形式（水面鱼）和失明的洞穴生活形式（洞穴鱼）组成。眼原基最初是在洞穴鱼发育过程中形成的，但随后它们会停止并退化，导致成年失明。首先退化的组织是晶状体，其次是视网膜。将正常的表面鱼胚胎晶状体移植到洞穴鱼的光学杯中可以恢复成年洞穴鱼的完整眼睛。一些基因，包括编码抗凋亡蛋白1a -晶体蛋白、热休克蛋白Hsp901和中线信号形态因子sonic hedgehog （shh）的基因，是洞穴鱼晶状体凋亡的候选调节因子。晶状体在保护视网膜免受凋亡细胞死亡以及角膜和巩膜的正常发育方面也很重要。该项目的总体目标是确定晶状体如何通过细胞凋亡而变得功能失调，以及异常晶状体如何反过来影响眼睛的整体生长和发育。前两个目标侧重于导致晶状体内细胞凋亡的事件。第一个目的是研究1a -晶体蛋白和1b -晶体蛋白下调在晶状体细胞凋亡中的作用。第二个目的是研究hsp901上调在晶状体细胞凋亡中的作用，以及它是否存在于shh和1 -晶体蛋白基因的推定凋亡通路中。后两个目标移动到晶状体外，聚焦于视网膜、角膜和巩膜、依赖于晶状体发育的光学成分，以及视网膜色素上皮（RPE）， RPE通常与晶状体合作，保护视网膜免于凋亡。第三个目的是研究可能参与控制视网膜生死通路的视网膜基因，以及晶状体在负责角膜和巩膜发育的迁移神经嵴细胞的分化和模式中的作用。最终目的是确定RPE是否与晶状体协同介导视网膜细胞存活。该应用程序的目的是结合晶状体显微外科手术操作、细胞和分子标记的使用、实验性基因过表达和抑制，以及基因分析来创造缺乏特定光学成分的鱼株，这些成分可用于测试眼睛生长协调的假设。这项研究旨在为晶状体如何协调眼睛生长以及失明是如何由这一过程中的缺陷导致的提供新的见解。这将填补我们对正常和异常眼睛发育的理解上的一个主要空白。公共卫生相关性：眼睛不同部位的精确发育协调是向大脑传输正确图像所必需的。本研究以盲洞鱼为模型，旨在提供有关晶状体在协调眼睛发育中的作用的新信息。研究结果将为研究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.