Cell Signaling in Embryonic Epithelial-to-Mesenchymal Transitions

胚胎上皮间质转化中的细胞信号转导

• 批准号: RGPIN-2014-03704
• 负责人: Kelly, Gregory
• 金额: $ 2.55万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566042
• 关键词: Cell; Signaling; Embryonic; Epithelial; Mesenchymal

Determining the intricacies of the numerous signal transduction events that go on within and between cells is one of the most actively investigated areas in the field of cellular and molecular biology. Basic biological research has led to important breakthroughs, which have been capitalized on by the pharmaceutical industry. Although that industry is focused on human health and disease and driven by profit, the overall importance of these signaling events must be underpinned by the fact that they are responsible for initiating, shaping and maintaining the life of every living organism, regardless of whether or not it has a backbone. Historically, these pathways were once naively thought to unfold in a linear fashion, but as more pathways and their protein participants were discovered it was realized that a significant amount of communication exists between them. This crosstalk at nodes where the pathways intersect has made the study of any one pathway in isolation obsolete, and thus their identification has garnered significant attention especially in the signal transduction field of developmental cell biology. My interests and that of many other labs in Canada and abroad lie with a group of 19 Wnt proteins and a much smaller, but just as influential group of three Hedgehog proteins, which drive several signaling pathways that contribute to the embryonic development of almost every animal on Earth. Fertilized eggs divide repeatedly to produce a pool of cells, which differentiate along specific paths if and only if they can correctly interpret the combination and levels of the Wnt and Hedgehog ligands presented to them. In some instances this interpretation leads to the transition of one cell type that had been firmly attached to a membrane and its neighbors, into another that is highly migratory and aggressive in its ability to colonize other regions of the embryo or body in the case of the adult. These transitions occur several times during embryogenesis, but most people are probably more familiar with those associated with metastatic cancer, where in many instances fully differentiated cells later in life are reprogrammed mistakably due to having again received the same Hedgehog or Wnt ligands. To further complicate our understanding of the signal transduction events that go on within and between embryonic cells, we and others have recently found that in the absence of a Wnt protein, highly reactive oxygen species naturally generated by living cells and at levels that are not dangerous to them, can prime the Wnt signaling pathway in preparation for its full activation by the ligand. In the example of the differentiated cells this ability to prime a signaling pathway could have dire consequences especially to those cells that have inadvertently retrieved a Wnt ligand. My objectives are to first determine how the Wnt and Hedgehog pathways are activated during mouse and zebrafish embryonic development and then uncover the extent of the signaling crosstalk between the pathways at specific times, and finally to identify how the node(s) or other proteins in the pathways are affected by reactive oxygen species. I am confident that attaining these goals will lead to a better understanding of the communication crosstalk that ensures the correct flow of molecular information is made available to instruct one cell type to adopt a new fate. Towards that end, I expect that the publications and presentations of this basic biological research will be of significant interest and applicable to many areas of what worldwide is presently and will continue to be, a high profile and highly competitive field of developmental, cell, molecular and chemical biology.

确定细胞内和细胞间发生的众多信号转导事件的复杂性是细胞和分子生物学领域最活跃的研究领域之一。基础生物学研究带​​来了重要突破，制药业也利用了这些突破。尽管该行业关注人类健康和疾病并受利润驱动，但这些信号事件的总体重要性必须以以下事实为基础：它们负责启动、塑造和维持每个生物体的生命，无论它是否有骨干。从历史上看，这些通路曾经被天真地认为以线性方式展开，但随着更多通路及其蛋白质参与者的发现，人们意识到它们之间存在大量的通讯。通路交叉节点处的这种串扰使得任何一种通路的孤立研究都过时了，因此它们的识别引起了人们的广泛关注，特别是在发育细胞生物学的信号转导领域。我以及加拿大和国外许多其他实验室的兴趣在于一组 19 个 Wnt 蛋白和一个小得多但同样有影响力的三个 Hedgehog 蛋白组，它们驱动多个信号通路，促进地球上几乎所有动物的胚胎发育。受精卵反复分裂产生一群细胞，当且仅当它们能够正确解释呈现给它们的 Wnt 和 Hedgehog 配体的组合和水平时，它们才会沿着特定的路径分化。在某些情况下，这种解释导致一种牢固附着在膜及其邻近细胞上的细胞类型转变为另一种细胞类型，这种细胞类型具有高度迁移性和侵略性，能够在胚胎或身体的其他区域定殖（对于成人而言）。这些转变在胚胎发生过程中发生多次，但大多数人可能更熟悉那些与转移性癌症相关的转变，在许多情况下，完全分化的细胞在生命后期由于再次接受相同的 Hedgehog 或 Wnt 配体而被错误地重新编程。为了进一步复杂化我们对胚胎细胞内和胚胎细胞间信号转导事件的理解，我们和其他人最近发现，在没有 Wnt 蛋白的情况下，活细胞自然产生的高活性氧物质（其水平对它们没有危险）可以启动 Wnt 信号通路，为配体的完全激活做好准备。在分化细胞的例子中，这种启动信号通路的能力可能会产生可怕的后果，特别是对于那些无意中恢复了 Wnt 配体的细胞。我的目标是首先确定 Wnt 和 Hedgehog 通路在小鼠和斑马鱼胚胎发育过程中如何被激活，然后揭示通路之间在特定时间的信号串扰程度，最后确定通路中的节点或其他蛋白质如何受到活性氧的影响。我相信，实现这些目标将有助于更好地理解通讯串扰，从而确保分子信息的正确流动，以指导一种细胞类型采取新的命运。为此，我预计这项基础生物学研究的出版物和演示将引起人们的极大兴趣，并适用于世界范围内目前并将继续成为备受瞩目且竞争激烈的发育、细胞、分子和化学生物学领域的许多领域。