Hematopoietic and Immune Development in the Human Chorion

项目摘要/摘要：在人类产前发育过程中，造血发生在多个部位。在……里面 除了原始的胚胎内造血组织外，现在人们认识到胚胎外的 组织--胎盘和绒毛膜--含有造血干细胞。造血干细胞的存在 这些组织中的细胞增加了这样一种可能性，即它们积极贡献了包含在 胚胎外的组织。在这项建议中，我们关注的是人的胎膜，特别是绒毛膜。 巨噬细胞存在于绒毛膜中，可能作为感染的哨兵和第一反应细胞。 以及母体细胞的入侵。这些巨噬细胞的存在表明，绒毛膜不仅仅是一个 惰性身体屏障。我们假设人类绒毛膜是一种免疫活性屏障，含有 巨噬细胞与绒毛膜中的其他细胞一起，从造血干细胞原位发育而来 维持母胎界面，防止孕期胎儿感染和免疫排斥反应。 在三个具体目标中的第一个，我们将调查绒毛膜造血干细胞是否作为局部 在绒毛膜中发现的单核细胞前体的来源。不同孕龄的组织将 使用流式细胞术、造血祖细胞培养和移植模型进行检测，使用 免疫缺陷小鼠，以确定存在于绒毛膜的造血祖细胞的类型。 实验将集中在展示绒毛膜中活跃的骨髓生成。在第二个目标中，我们将探索 绒毛膜微环境在巨噬细胞发育和功能中的作用。间充质 基质细胞和细胞滋养细胞构成了绒毛膜中的造血龛，这将在 培养以检测其对单核细胞发育和巨噬细胞成熟的影响。我们假设这些 细胞类型支持M2巨噬细胞的发育，以培养抗炎环境 绒毛膜。这将在第三个目标中得到更具体的测试，在该目标中，我们将调查 绒毛膜细胞在预防母体T细胞排斥反应中的免疫调节作用初步数据显示， 在母体和胎儿来源的绒毛膜中都存在T细胞。外周血淋巴细胞的来源和分布 将在不同的妊娠阶段对绒毛膜进行进一步的研究。此外，我们将确定T细胞是否 如果它们在任何特定的T细胞亚型中富含，那么它们就是活跃的。来自邻近蜕膜的T细胞将是 分析比较，以及来自脾的胎儿T细胞。我们将探讨绒毛膜的作用 巨噬细胞、间充质基质细胞和细胞滋养层细胞对T细胞活化的调节。同舟共济 这些目标将表明绒毛膜巨噬细胞是从绒毛膜中的干细胞群局部发育而来的。 此外，这些巨噬细胞与其他细胞群一起有助于产生活性 广泛的母胎界面的免疫屏障，包括胎膜，这 具有抵御母体淋巴细胞感染和入侵的功能。

Project Summary/Abstract: Hematopoiesis occurs at multiple sites during human prenatal development. In addition to the primary intraembryonic hematopoietic tissues, it is now recognized that the extra-embryonic tissues – the placenta and chorion – contain hematopoietic stem cells. The presence of hematopoietic stem cells in these tissues raises the possibility that they actively contribute to the pool of blood cells contained in the extra-embryonic tissues. In this proposal we focus on the human fetal membranes, specifically the chorion. Macrophages are present in the chorion and presumably act as sentinels and first responders to infection as well as invasion by maternal cells. The presence of these macrophages suggests that the chorion is not just an inert physical barrier. We hypothesize that the human chorion is an immunologically active barrier containing macrophages that develop in situ from hematopoietic stem cells that together with other cells in the chorion maintain the maternal-fetal interface to prevent infection and immune rejection of the fetus during pregnancy. In the first of three specific aims, we will investigate if chorionic hematopoietic stem cells serve as a local source of precursors for monocytic cells found in the chorion. Tissues across a range of gestational ages will be examined using flow cytometry, hematopoietic progenitor cultures, and a transplant model, using immunodeficient mice, to determine the types of hematopoietic precursors that exist in the chorion. Experiments will focus on demonstrating active myelopoiesis in the chorion. In the second aim, we will explore the role of the chorionic microenvironment in the development and function of macrophages. Mesenchymal stromal cells and cytotrophoblasts comprise the hematopoietic niche in the chorion, which will be studied in culture to test their effects on monocyte development and macrophage maturation. We hypothesize that these cell types support the development of M2 macrophages to foster an anti-inflammatory environment in the chorion. This will be more specifically tested in the third aim, in which we will investigate the immunomodulatory role of chorion cells in preventing rejection by maternal T-cells. Preliminary data show the presence of T cells in the chorion of both maternal and fetal origin. The origins and distribution of T-cells in the chorion will be further investigated at different gestations. Additionally, we will determine if the T-cells are active and if they are enriched in any specific T-cell subtypes. T-cells from the adjacent decidua will be analyzed for comparison as well as fetal T-cells from the spleen. We will explore the roles of chorionic macrophages, mesenchymal stromal cells, and cytotrophoblasts in the regulation of T-cell activation. Together these aims will show that chorionic macrophages develop locally from a population of stem cells in the chorion. Also, that these macrophages, in conjunction to other cell cellular populations contribute to generate an active immunological barrier at the extensive maternal-fetal interface that includes the fetal membranes, which function to ward off infection and invasion of maternal lymphocytes.