FUNCTIONAL CYTOLOGY OF THE PLACENTA AND FETAL MEMBRANES

在人类中，绝大多数母胎之间的营养交换， 毒素或有害微生物是由胎盘介导的。 是 因此对我们了解胎儿和新生儿 营养和健康问题，以确定其机制 胎盘滋养层选择性地吸收来自 母亲的血 本提案所包含的实验将 检查胎盘的各种结构和功能方面 滋养层 胎盘发育和功能的一个重要特征 是细胞滋养层向合体滋养层的分化， 伴随着细胞融合的过程。 目前，人们所知甚少 关于这个关键的，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， 纯细胞滋养层细胞群，并检查调节 体外滋养层分化，采用多种因素 已知会影响其他系统中的分化，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， 来自胎盘成纤维细胞培养物的条件培养基 和巨噬细胞，扰乱细胞骨架的药物， 基质成分 我们将确定合胞体形成的程度 通过各种形态学和生物化学技术。 为 滋养层细胞经历分化，我们将检查在滋养层细胞的变化。 表达的两种重要蛋白质的分布和合成， 细胞表面，转铁蛋白受体和EGF受体，以及两种 重要的细胞骨架蛋白，细胞角蛋白和桥粒斑蛋白。 的 后者在经历融合的细胞系统中特别有意义 由于细胞骨架重排和细胞消失， 这种转变将伴随着这种转变。 具体目标二将扩大 我们早期对滋养层细胞铁代谢的研究。 我们将 检查转铁蛋白介导的铁摄取和铁的释放 在不同的分化阶段。 其他研究将检查 转铁蛋白受体调节的发育变化 合成和分配。 相关研究将确定 滋养层铁代谢中的铁蛋白通过检查其摄取， 生物合成和释放。 第三个具体目标是证明 胎盘绒毛中酸性细胞内室的分布， 在离体滋养层细胞中。 酸性细胞内区室是 受体-配体解离和分选的重要位置， 也是铁从转铁蛋白解离的位点。 综合这些 AIMS将为滋养层细胞提供重要的新信息 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.