Regulation of Eye Morphogenesis

 描述（由申请人提供）：先天性眼部畸形，如小眼症、无眼症和缺损（MAC），在3- 4，000人中约有1人患病，是全球25%以上儿童失明的原因。仅缺损就可能占儿童失明的10%。因此，了解眼发育的分子机制是非常重要的。虽然确定了几个致病基因，但需要更多的努力来确定下游靶点和眼睛形态发生的基础事件。豪猪基因（PORCN）的突变导致人类疾病局灶性皮肤发育不全（FDH，Goltz综合征），这是一种与（MAC）相关的X连锁显性多系统出生缺陷。Porcn是介导Wnt棕榈酰化的0-酰基转移酶，Wnt是一个分泌的高度保守的糖蛋白大家族，其激活不同的途径，典型的Wnt/β-连环蛋白途径和两个不太明确的非典型途径，Wnt/Ca 2+和平面细胞极性。在小鼠中的时间控制和组织特异性失活显示，Porcn需要早期外翻和视泡的区域化，后来关闭视裂。使用遗传小鼠模型，RNAseq和培养方法，我们建议确定Porcn和Wnt通路在视裂闭合过程中调节细胞间相互作用的作用（目的1）。在目标2中，我们将研究 Porcn和非经典的Wnt信号在视野发育和视泡形态发生中的作用。此外，Rho GTdR Cdc 42是细胞连接组装和肌动蛋白细胞骨架的关键调节因子，作用于不同信号传导途径的下游，包括非经典Wnt信号传导。在目的3中，我们建议研究Cdc 42在调节视泡和视杯的形态发生中的作用。本文提出的研究将是理解控制眼睛形态发生的细胞和分子机制的关键一步，对于推进眼部疾病的治疗和再生工作非常重要。

 DESCRIPTION (provided by applicant): Congenital ocular malformations such as microphthalmia, anophthalmia and coloboma (MAC) are prevalent in ~1 in 3-4,000 individuals and are the cause for over 25% of childhood blindness worldwide. Coloboma alone may account up to 10% of childhood blindness. Therefore, it is vitally important to understand the molecular mechanisms underlying ocular development. While several causative genes are identified, more effort is required to define the downstream targets and events underlying eye morphogenesis. Mutations in the Porcupine gene (PORCN) cause the human disease Focal Dermal Hypoplasia (FDH, Goltz Syndrome), an X-linked dominant multisystem birth defect associated with (MAC). Porcn is an O-acyltransferase that mediates palmitoylation of Wnts, a large family of secreted, highly conserved glycoproteins that activate distinct pathways, the canonical Wnt/ß-catenin pathway and two less well-defined non-canonical pathways, Wnt/Ca2+ and Planar Cell Polarity. Temporally controlled and tissue-specific inactivation in mouse revealed that Porcn is required early for evagination and regionalization of the optic vesicle and later for closure of the optic fissure. Using genetic mouse models, RNAseq and culture approaches, we propose to determine the role of Porcn and Wnt pathways in regulating cell-cell interactions during closure of the optic fissure (Aim 1). In Aim 2, we will investigate the role of Porcn and non-canonical Wnt signaling during eye field development and morphogenesis of the optic vesicle. Furthermore, the Rho GTPase Cdc42 is a key regulator of cell junction assembly and actin cytoskeleton, acting downstream of distinct signaling pathways, including non-canonical Wnt signaling. In Aim 3, we propose to investigate the role of Cdc42 in regulating morphogenesis of the optic vesicle and optic cup. The studies proposed here will be a critical step toward an understanding of the cellular and molecular mechanisms controlling eye morphogenesis and important for advancing treatment and regenerative efforts of ocular diseases.