Hematopoietic and Immune Development in the Human Chorion

项目摘要/摘要：造血发生在多个网站在人类产前发育。在 除了最初的胚内造血组织外，现在认识到胚外造血组织也是一种重要的造血组织。 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它们积极贡献于血液中所含的血细胞池的可能性。 胚胎外组织在这个建议中，我们专注于人类胎儿膜，特别是绒毛膜。 巨噬细胞存在于绒毛膜中，可能作为哨兵和感染的第一反应者， 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 惰性物理屏障。我们假设人绒毛膜是一种免疫活性屏障， 由造血干细胞原位发育而成的巨噬细胞， 维持母胎界面，预防妊娠期感染和胎儿免疫排斥。 在三个具体目标中的第一个，我们将研究绒毛膜造血干细胞是否作为局部造血干细胞， 绒毛膜中发现的单核细胞的前体来源。不同胎龄的组织 使用流式细胞术、造血祖细胞培养物和移植模型进行检查， 免疫缺陷小鼠，以确定存在于绒毛膜中的造血前体的类型。 实验将集中于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。充质 基质细胞和细胞滋养层构成绒毛膜中的造血小生境，这将在 培养以测试它们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，以在 绒毛膜这将在第三个目标中得到更具体的检验，在这个目标中，我们将研究 绒毛膜细胞在防止母体T细胞排斥反应中的免疫调节作用。初步数据显示， 母体和胎儿来源的绒毛膜中存在T细胞。T细胞的起源和分布 绒毛膜将在不同妊娠期进一步研究。此外，我们将确定T细胞是否 活性，以及是否富含任何特定的T细胞亚型。来自邻近蜕膜的T细胞将 以及来自脾的胎儿T细胞进行比较分析。我们将探讨绒毛膜 巨噬细胞、间充质基质细胞和细胞滋养层在调节T细胞活化中的作用。一起 这些目标将显示绒毛膜巨噬细胞从绒毛膜中的干细胞群体局部发育。 此外，这些巨噬细胞与其他细胞群体一起有助于产生活性的 免疫屏障在广泛的母胎界面，包括胎膜， 具有抵御感染和母体淋巴细胞入侵的功能。

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.