Analysis of Trophoblast Cell Motility

描述（由申请方提供）：胚胎植入子宫并随后形成胎盘是哺乳动物发育的独特和关键特征。它们由滋养层细胞介导，滋养层细胞来自胚泡的上皮滋养外胚层细胞。在植入时，它们转化为侵入性细胞，其取代并吞噬子宫上皮细胞，以穿透子宫基质并与母体血液供应建立血管连接。与上皮滋养外胚层转化为运动滋养层和随后的内皮滋养层巨细胞相关的细胞行为对于植入和胎盘形成的成功以及最终对于胚胎本身的发育是重要的。然而，我们对这两个转变中涉及的关键细胞事件及其调节的理解仍然非常初步。在这一提议中被测试的中心假设是，滋养层细胞运动行为的调节变化是其在着床和胎盘形成中功能的基础。拟进行的实验集中在两个方面的滋养层巨细胞分化：第一，上皮滋养外胚层的过渡到运动的滋养层，第二，从运动的滋养层的过渡到滋养层巨细胞。滋养外胚层运动的开始受氨基酸的可用性调节，特别是亮氨酸和精氨酸。由这些氨基酸激活的信号传导机制在调节滋养外胚层的膨胀活性的发生中的功能将被表征，特别是关于一氧化氮和多胺合成的作用。着床后，滋养层细胞经过终末分化为滋养层巨细胞，形成卵黄囊胎盘血窦的复杂吻合网络。这一过程与运动性和细胞形状的进一步变化有关，以启动窦的形成，以及细胞间隙组织和细胞-细胞粘附的特定变化，我们假设这将稳定和加强最终结构。层粘连蛋白亚型在指导滋养层细胞行为中的作用，以及细胞骨架和粘附变化在维持其结构中的重要性将被研究。这些实验将阐明调节滋养层细胞行为和分化的机制，并将提供对胚胎植入更深入的全面了解。

DESCRIPTION (provided by applicant): Implantation of the embryo into the uterus and subsequent formation of the placenta are unique and critical features of mammalian development. They are mediated by the trophoblast cells, which arise from the epithelial trophectoderm cells of the blastocyst. At the time of implantation they transform into invasive cells that displace and phagocytose the uterine epithelial cells in order to penetrate the uterine stroma and make vascular connections with the matemal blood supply. The cellular behaviors associated with the transformation of the epithelial trophectoderm into a motile trophoblast and subsequently to an endothelial trophoblast giant cell are important for the success of implantation and placentation and ultimately for the development of the embryo itself. However our understanding of the key cellular events involved in these two transitions, and of their regulation, is still quite rudimentary. The central hypothesis being tested in this proposal is that regulated changes in the motile behavior of trophoblast cells are the basis for their function in implantation and placentation. The proposed experiments focus on two aspects of trophoblast giant cell differentiation: first, the transition of epithelial trophectoderm to motile trophoblast, and second, the transition from motile trophoblast-to-trophoblast giant cell. The onset of motility in the trophectoderm is regulated by the availability of amino acids, in particular leucine and arginine. The functions of the signaling mechanisms activated by these amino acids in regulating the onset of protrusive activity of the trophectoderm will be characterized, especially with respect to the roles of nitric oxide and polyamine synthesis. After implantation, trophoblast cells form the intricate anastomotic network of blood sinuses of the yolk sac placenta as they undergo terminal differentiation to trophoblast giant cells. This process is associated with further changes in motility and cell shape to initiate the formation of the sinuses, as well as specific changes in cytoskeletat organization and cell-cell adhesion, which we hypothesize will stabilize and reinforce the final structure. The roles of laminin isoforms in directing trophoblast behavior, and the importance of cytoskeletal and adhesive changes in maintaining their structure will be examined. These experiments will clarify the mechanisms regulating trophoblast cell behavior and differentiation, and will provide a deeper overall understanding of embryo implantation.