Regulation of Wnt Signaling during Vertebrate Development

脊椎动物发育过程中 Wnt 信号传导的调控

• 批准号: RGPIN-2021-03241
• 负责人: VanRaay, Terence
• 金额: $ 2.33万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761170
• 关键词: Regulation; Wnt; Signaling; during; Vertebrate

My research program and long-term goal is to understand the intricacies both within and between signaling pathways that ultimately work together to generate the complexity of life. The Wnt pathway is an essential pathway that is highly conserved across all metazoans and involves a complex signaling network that regulates many aspects of development and stem cell maintenance in the adult. At the most elemental level it can be divided into the Wnt/PCP pathway that controls cell polarity and migration and the Wnt/ß-catenin pathway that controls cell proliferation and differentiation. While these two pathways are mutually exclusive they do share some significant components and there is increasing evidence that these two pathways interact, whereby the Wnt/PCP pathway has been demonstrated to inhibit Wnt/ß-catenin. Using a well-developed zebrafish animal model, my NSERC DG sponsored research has uncovered the unique features of Nkd1 and Axin2, both negative feedback regulators of Wnt/ß-catenin signaling that act independently to maintain Wnt/ß-catenin signaling homeostasis to ensure proper patterning and formation of the metazoan body plan. A third mechanism involves the Wnt/PCP protein Vangl2 that we and others have demonstrated antagonizes Wnt/ß-catenin signaling, but unlike the rheostat model of Nkd1 and Axin2, Vangl2 functions to prevent activation of Wnt/ß-catenin signaling. Unfortunately, we still don't know how the rheostat model of Nkd1 or Axin2 antagonism translates into changes in gene expression or how Vangl2 inhibits Wnt/ß-catenin. My hypothesis is that they each uniquely and independently control different aspects of Wnt/ß-catenin that ultimately translates into altered target gene activation, which is the focus of Aim 1. In the second Aim, we investigate the molecular mechanisms in which Vangl2, and by extension, the Wnt/PCP pathway, exclude or prevent Wnt/ß-catenin signaling. We have found that certain Vangl2 mutant alleles sensitize the embryo to excess Wnt/ß-catenin, while other alleles do not. These different mutants provide a unique opportunity to understand the molecular interactions between these two pathways. In Aim 3, we combine the Nkd1, Axin2 and Vangl2 mutants to test the hypothesis that Nkd1 and/or Axin2 prevent Wnt/ß-catenin gain of function phenotypes in Wnt/PCP mutants. This last aim addresses the complexity of both Wnt/PCP and Wnt/ß-catenin to better understand how these two pathways remain exclusive even though they share several key signaling molecules. The importance of Wnt signaling in development and disease cannot be understated and we are only beginning to understand the intricacies of regulation beyond the simple on and off model. Further, the exclusive nature of Wnt/PCP and Wnt/ß-catenin is perplexing given the high conservation and their shared resources at the plasma membrane and a better understanding of this relationship will provide significant insight into the evolution of metazoan body plan.

我的研究计划和长期目标是了解信号通路内部和之间的复杂性，这些信号通路最终共同产生生命的复杂性。Wnt通路是所有后生动物中高度保守的重要通路，涉及调节成体发育和干细胞维持的许多方面的复杂信号传导网络。在最基本的水平上，它可以分为控制细胞极性和迁移的Wnt/PCP途径和控制细胞增殖和分化的Wnt/β-连环蛋白途径。虽然这两种途径是相互排斥的，但它们确实共享一些重要的组分，并且有越来越多的证据表明这两种途径相互作用，由此Wnt/PCP途径已被证明抑制Wnt/β-连环蛋白。使用一个成熟的斑马鱼动物模型，我的NSERC DG赞助的研究发现了Nkd 1和Axin 2的独特功能，这两个Wnt/β-catenin信号的负反馈调节剂独立地发挥作用，以维持Wnt/β-catenin信号稳态，以确保后生动物身体计划的正确模式和形成。第三种机制涉及Wnt/PCP蛋白质Vangl 2，我们和其他人已经证明Vangl 2拮抗Wnt/β-连环蛋白信号传导，但与Nkd 1和Axin 2的变阻器模型不同，Vangl 2的功能是阻止Wnt/β-连环蛋白信号传导的激活。不幸的是，我们仍然不知道Nkd 1或Axin 2拮抗作用的变阻器模型如何转化为基因表达的变化或Vang 12如何抑制Wnt/β-连环蛋白。我的假设是，它们各自独特且独立地控制Wnt/β-catenin的不同方面，最终转化为改变的靶基因激活，这是Aim 1的焦点。在第二个目标中，我们研究了Vangl 2以及延伸的Wnt/PCP途径排除或阻止Wnt/β-连环蛋白信号传导的分子机制。我们已经发现某些Vangl 2突变等位基因使胚胎对过量的Wnt/β-连环蛋白敏感，而其他等位基因则不然。这些不同的突变体提供了一个独特的机会，了解这两个途径之间的分子相互作用。在目的3中，我们将Nkd 1、Axin 2和Vangl 2突变体联合收割机以测试Nkd 1和/或Axin 2阻止Wnt/PCP突变体中Wnt/β-连环蛋白获得功能表型的假设。这最后一个目标解决了Wnt/PCP和Wnt/β-连环蛋白的复杂性，以更好地理解这两种途径如何保持排他性，即使它们共享几个关键信号分子。Wnt信号在发育和疾病中的重要性不容低估，我们才刚刚开始了解调控的复杂性，而不仅仅是简单的开和关模型。此外，Wnt/PCP和Wnt/β-连环蛋白的排他性是令人困惑的，因为它们在质膜上的高度保守性和共享资源，更好地理解这种关系将为后生动物身体计划的进化提供重要的见解。