Transcriptional control of collective cell migration

项目摘要/摘要 关键的生理和病理过程，如伤口愈合、血管形成和癌症 转移，依赖于定向的集体细胞迁移，从而使细胞组集体极化和移动 以有序的方式聚集在一起。细胞集体定向迁移的能力在一定程度上取决于 组织特异性转录输入，定义了表达的基因的补体，从而决定了它们的能力 迁徙。这个项目的长期目标是了解组织特异性转录调控因子是如何 控制潜在的定向集体细胞迁移的基本细胞过程。为达到这一目的，简化的 脊索动物的胚胎，海鞘动物，将被用来研究Pre-Pre-Pre 心脏中胚层细胞，称为“干腹侧细胞”(TVCs)。TVC提供了最简单的可能模型 活体胚胎中定向的集体细胞迁移。在胚胎的两侧，只有两个细胞一起迁移 并显示与迁移方向一致的清晰的首尾两极：首领TVC显示 宽阔的前缘和比拖车更明显的突出。此前已确定，环保部， 成纤维细胞生长因子信号转导和FoxF转录输入决定血管内皮细胞 迁移。此外，TVCs严格地在内胚层和外胚层之间迁移，这是 中胚层心脏祖细胞。已确定这些周围组织有助于管道化 TVCs向着集体极化和定向迁移的天生动力。拟议研究的目标是 了解转录控制的内在TVC特性如何与外在信号相互作用 确定胚胎中的集体极性和定向迁移。初步研究表明，该基因 编码盘状结构域受体(DDR)受MESP、成纤维细胞生长因子和FoxF转录调控 TVCs，在那里它促进与表皮的粘连。使用新开发的定量成像方法， 将分析控制DDR表达、定位和活性的详细机制。假说 DDR和血管内皮生长因子受体(VEGFR)之间的细胞自主拮抗作用 在表皮和内胚层之间迁移的TVCs的信号位置将被测试。初步 观察表明，DDR通过调节囊泡运输促进与表皮的粘连。这个 假设DDR作用于Rab4/Rab11阳性内体促进整合素循环至血浆 将对膜进行测试。最后，受监管的集体移徙候选效应者的职能将是 广泛使用TVC特异性CRISPR/Cas9介导的功能损失分析和高含量 表型分析。控制亚细胞过程的生物分子网络的临时模型 将构建基本的TVC行为。将特别关注DDR的候选调制器， VEGFR和整合素的功能。该项目的完成将阐明系统层面的机制链接 内在的转录输入和外在信号来定义细胞特有的行为。

PROJECT SUMMARY / ABSTRACT Critical physiological and pathological processes, such as wound healing, blood vessel formation and cancer metastasis, rely on directed collective cell migrations, whereby groups of cells collectively polarize and move together in an orderly fashion. The ability of cell collectives to migrate directionally is determined in part by the tissue-specific transcriptional inputs that define the complement of expressed genes and thus their competence to migrate. The long-term goal of this project is to understand how tissue-specific transcription regulators control the basic cellular processes underlying directed collective cell migration. To this aim, the simplified embryos of a chordate species, the ascidian Ciona intestinalis, will be used to study the migration of pre- cardiac mesoderm cells, called “trunk ventral cells” (TVCs). The TVCs provide the simplest possible model of directed collective cell migration in live embryos. On each side of the embryo, only two cells migrate together and display a clear Leader-Trailer polarity aligned with the direction of migration: the leader TVC displays a broad leading edge and more conspicuous protrusions than the trailer. It was previously established that Mesp, Fibroblast growth factor (Fgf) signaling and FoxF transcriptional inputs determine the ability of TVCs to migrate. Moreover, TVCs migrate strictly between the endodermal and ectodermal germ layers, a hallmark of mesodermal cardiac progenitors. It was determine that these surrounding tissues contribute to canalizing TVCs' innate motility towards collective polarity and directed migration. The goal of the proposed research is to understand how transcriptionally-controlled intrinsic TVC properties interface with extrinsic signals to determine collective polarity and directed migration in the embryo. Preliminary studies suggested that the gene encoding the discoidin domain receptor (Ddr) is upregulated by Mesp, FGF and FoxF transcriptional inputs in the TVCs, where it promotes adhesion to the epidermis. Using newly developed quantitative imaging methods, the detailed mechanisms controlling Ddr expression, localization and activity will be analyzed. The hypothesis that a cell-autonomous antagonism between Ddr and vascular endothelial growth factor receptor (Vegfr) signaling positions the migrating TVCs between the epidermis and endoderm will be tested. Preliminary observations suggest that Ddr promotes adhesion to the epidermis by regulating vesicle trafficking. The hypothesis that Ddr acts in Rab4/Rab11-positive endosomes to promote the recycling of integrins to the plasma membrane will be tested. Finally, the functions of regulated candidate effectors of collective migration will be studied extensively using TVC-specific CRISPR/Cas9-mediated loss-of-function assays and high-content phenotypic analyses. A provisional model of the biomolecular network controlling the subcellular processes underlying TVC behavior will be built. Particular attention will be paid to the candidate modulators of Ddr, Vegfr and integrin functions. Completion of this project will illuminate the systems' level mechanisms linking intrinsic transcriptional inputs and extrinsic signals to define cell-specific behaviors.