Regulation of Eye Morphogenesis

 描述(申请人提供)：先天性眼畸形，如小眼炎、无眼症和眼球缺陷症(MAC)，在每3-4,000人中普遍存在，是全球超过25%的儿童失明的原因。仅缺陷症就可能占到儿童失明的10%。因此，了解眼球发育的分子机制至关重要。虽然已经确定了几个致病基因，但还需要更多的努力来定义眼睛形态发生的下游靶点和事件。豪猪基因(PORCN)的突变导致人类疾病局灶性真皮发育不全(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是一种O-酰基转移酶，它介导Wnts的棕榈酰化，Wnts是一个分泌的、高度保守的糖蛋白家族，激活不同的途径，典型的Wnt/？-catenin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。在小鼠的时间控制和组织特异性失活中发现，PORCN在早期需要用于视泡的外翻和区域化，后来用于关闭视裂。利用小鼠遗传模型、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(目标1)。在目标2中，我们将调查 PORCN和非典型Wnt信号在眼场发育和视泡形态发生中的作用。此外，Rho GTPase CDc42是细胞连接组装和肌动蛋白细胞骨架的关键调节因子，作用于不同的信号通路的下游，包括非规范的Wnt信号。在目标3中，我们建议研究Cdc42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了解控制眼睛形态发生的细胞和分子机制的关键一步，并对推进眼部疾病的治疗和再生努力具有重要意义。

 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.