Regulation of Eye Morphogenesis

眼睛形态发生的调节

• 批准号: 9251968
• 负责人: SABINE FUHRMANN
• 金额: $ 33.32万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9251968
• 关键词: Regulation; Eye; Morphogenesis

DESCRIPTION (provided by applicant): Congenital ocular malformations such as anophthalmia, microphthalmia and coloboma 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. Wnts belong to a family of secreted, highly conserved glycoproteins that control key processes during development, disease and regeneration. Wnt signaling is very complex; in mammals, 19 Wnts and 10 Frizzled receptors have been identified that can activate the canonical, Wnt/�-catenin pathway and two less well-defined non-canonical pathways, Wnt/Ca2+ and Planar Cell Polarity. This complexity is reflected by the different roles of Wnt signaling during eye development. In this proposal, we aim to address two important questions; 1) How does non-canonical Wnt signaling regulate early eye development? 2) What is the cellular mechanism by which Wnt signaling controls closure of the optic fissure? To begin to tease this apart, we are focusing on the function of Porcupine (Porcn) that mediates posttranslational modification of Wnts. Porcn is a membrane-bound O-acyltransferase that resides in the endoplasmatic reticulum and mediates palmitoylation critical for the secretion and signaling activity of Wnt ligands. The human disease Focal Dermal Hypoplasia (FDH, Goltz Syndrome) is an X-linked, rare dominant disorder caused by mutations in PORCN. About 20% of FDH patients exhibit microphthalmia, anophthalmia, and coloboma (MAC), among several other severe developmental defects. While Porcn mutations cause MAC, we have no current understanding how depletion of Porcn/Wnt results in severe ocular malformations such as anophthalmia and coloboma. Using temporal and tissue-specific inactivation of Porcn, identification of potential targets and diverse in vitro approaches, we propose to identify the cellular interactions regulating closure of the optic fissure (Aim 1), investigate the role of non-canonical Wnt signaling during eye field and optic vesicle formation (Aim 2). In Aim 3, we will investigate the role of the small GTPase Cdc42 in optic vesicle evagination and optic cup morphogenesis. Our approach will identify novel roles for Wnt signaling during eye development that will be important for treatment and regenerative efforts. The etiology of anophthalmia and coloboma in humans is complex and can result from disruption of several factors. The studies proposed here will advance our knowledge toward an understanding of the cellular and molecular mechanisms controlling eye morphogenesis at the earliest stages and during closure of the optic fissure.

描述（由申请人提供）：先天性眼部畸形，如无眼症、小眼症和缺损，在3- 4000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。Wnt属于一个分泌的、高度保守的糖蛋白家族，控制发育、疾病和再生过程中的关键过程。Wnt信号转导非常复杂;在哺乳动物中，已经鉴定了19种Wnt和10种Frizzled受体，它们可以激活经典的Wnt/β-连环蛋白途径和两种不太明确的非经典途径，Wnt/Ca 2+和平面细胞极性。这种复杂性反映在眼睛发育过程中Wnt信号的不同作用。在这个提议中，我们的目标是解决两个重要的问题：1）非经典Wnt信号如何调节早期眼睛发育？2)Wnt信号传导控制视裂闭合的细胞机制是什么？为了开始梳理这个分开，我们正在集中在介导Wnt翻译后修饰的豪猪（Porcn）的功能。Porcn是一种膜结合O-酰基转移酶，存在于内质网中，介导对Wnt配体的分泌和信号传导活性至关重要的棕榈酰化。人类疾病局灶性皮肤发育不全（FDH，Goltz综合征）是一种X连锁的罕见显性疾病，由PORCN突变引起。大约20%的FDH患者表现出小眼症、无眼症和缺损（MAC），以及其他几种严重的发育缺陷。虽然Porcn突变导致MAC，但我们目前还不了解Porcn/Wnt缺失如何导致严重的眼部畸形，如无眼症和缺损。利用Porcn的时间和组织特异性失活，鉴定潜在靶点和多种体外方法，我们提出鉴定调节视裂闭合的细胞相互作用（Aim 1），研究非经典Wnt信号传导在视野和视泡形成过程中的作用（Aim 2）。在目标3中，我们将研究小GTdR Cdc 42在视泡外翻和视杯形态发生中的作用。我们的方法将确定Wnt信号在眼睛发育过程中的新作用，这对治疗和再生工作至关重要。人类无眼症和缺损的病因学是复杂的，可能是由于几个因素的破坏。本文提出的研究将促进我们对控制眼形态发生的细胞和分子机制的理解，在最早期和视裂闭合期间。