FUNCTIONAL CYTOLOGY OF THE PLACENTA AND FETAL MEMBRANES

在人类中，绝大多数母婴之间的营养交换， 毒素或有害生物是由胎盘调节的。它是 因此，对我们理解胎儿和新生儿具有重要意义 营养和健康问题，以确定 胎盘滋养层细胞选择性地吸收来自 母血。这项提案中包含的实验将 检查胎盘的各种结构和功能 滋养细胞。胎盘发育和功能的一个重要特征 细胞滋养层细胞分化为合体滋养层细胞， 伴随着细胞融合的过程。目前，人们对此知之甚少 关于对这一关键但不寻常的过渡的监管。在 第一个具体目标，我们将利用我们的能力分离一个 纯化细胞滋养层细胞群，并检测其调节 利用多种因素体外诱导滋养层细胞分化 已知会影响其他系统的分化，特别是那些 细胞融合发生的地方。这些药物包括EGF、胰岛素、IGF、 前列腺素，来自胎盘成纤维细胞培养的条件培养液 巨噬细胞，扰乱细胞骨架的药物，以及细胞外 矩阵组件。我们将确定合胞体形成的程度 通过各种形态和生化技术。作为 滋养层细胞经历分化，我们将观察滋养层细胞 两种重要蛋白的分布和合成 细胞表面、转铁蛋白受体和EGF受体的变化 重要的细胞骨架蛋白、细胞角蛋白和桥粒蛋白。这个 后者对正在进行融合的细胞系统特别感兴趣 由于细胞骨架重排和细胞消失 交汇点将伴随着这一过渡。具体目标二将延长 我们早期对滋养层细胞铁代谢的研究。我们会 检测转铁蛋白介导的铁摄取和铁的释放 在分化的不同阶段。其他研究将检查 转铁蛋白受体调控的发育变化 综合与分配。相关研究将确定 铁蛋白在滋养层细胞铁代谢中的作用 生物合成和释放。第三个具体目标是演示 酸性细胞内隔膜在胎盘绒毛和胎盘中的分布 在分离的滋养层细胞中。酸性的细胞内隔间是 受体-配体解离和分选的重要位置和 也是铁从转铁蛋白解离的位置。把这些放在一起 AIMS应该会产生关于滋养层细胞的重要新信息 分化和功能。

In humans the vast majority of maternal-fetal exchanges of nutrients, toxins or harmful organisms is mediated by the placenta. It is therefore of great importance to our understanding of fetal and neonatal nutritional and health problems to ascertain the mechanisms by which the placental trophoblast selectively absorbs substances from the maternal blood. The experiments encompassed in this proposal will examine various structural and functional aspects of placental trophoblast. An important feature of placental development and function is the differentiation of cytotrophoblast into syncytiotrophoblast, accompanied by the process of cell fusion. At present, little is known about the regulation of this critical, but unusual, transition. In the first specific aim, we will take advantage of our ability to isolate a pure cytotrophoblast population and examine the regulation of trophoblast differentiation in vitro, employing a variety of factors known to affect differentiation in other systems, particularly those few where cell fusion occurs. These agents include EGF, insulin, IGF's, prostaglandins, conditioned media from cultures of placental fibroblasts and macrophages, drugs which perturb the cytoskeleton, and extracellular matrix components. We will determine the extent of syncytium formation by a variety of morphological and biochemical techniques. As the trophoblast undergoes differentiation we will examine changes in the distribution and synthesis of two important proteins expressed on the cell surface, transferrin receptor and EGF receptor, and changes in two important cytoskeletal proteins, cytokeratin and desmoplakin. The latter are of particular interest in a cell system undergoing fusion since rearrangement of the cytoskeleton and disappearance of cell junctions would accompany this transition. Specific aim two will extend our earlier studies of iron metabolism by trophoblast cells. We will examine the transferrin-mediated uptake of iron and the release of iron at different stages of differentiation. Other studies will examine developmental changes in the regulation of transferrin receptor synthesis and distribution. Related studies will define the role of ferritin in trophoblast iron metabolism by examining its uptake, biosynthesis and release. The third specific aim is to demonstrate the distribution of acidic intracellular compartments in placental villi and in isolated trophoblast cells. Acidic intracellular compartments are important locations of receptor-ligand dissociation and sorting and are also the site of iron dissociation from transferrin. Together these aims should result in significant new information on trophoblast differentiation and function.