Lymphopoietic development in the extra-embryonic yolk sac

胚胎外卵黄囊的淋巴细胞发育

• 批准号: 7751826
• 负责人: Mervin C. YODER
• 金额: $ 35.94万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-12-23 至 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7751826
• 关键词: Address; Adult; Antibodies; Aorta; Appearance; Autoimmune Diseases; B-Lymphocytes; Blood Cells; Blood Circulation; Blood flow; Bone Marrow; Calcium; Cardiac; Cardiac Myocytes; Cell Line; Cells; Coculture Techniques; Data; Development; Embryo; Erythrocytes; Extrahepatic; Fetal Liver; Goals; Gonadal structure; Greater sac of peritoneum; Growth; Growth Factor; Hematologist; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Home environment; Homing; Human Development; In Vitro; Knockout Mice; Liver; Lymphocyte; Lymphoid; Lymphoid Cell; Lymphopoiesis; Marrow; Megakaryocytes; Mesonephric structure; Modeling; Molecular; Mus; Organ; Paraaortic; Pathway interactions; Population; Production; Proteins; Reporting; Seeds; Signal Pathway; Site; Sodium; Stem cells; Stromal Cells; Time; Wild Type Mouse; Work; Yolk Sac; fetal; human subject; in vivo; innovation; leukemia; macrophage; mutant; novel; novel strategies; prevent; progenitor; public health relevance

DESCRIPTION (provided by applicant): The overall goal of the present work is to determine the mechanisms that permit the emergence of B lymphoid cells in the extraembryonic yolk sac and the para aortic splanchnopleura (P-Sp) and facilitate the homing of these cells into the peritoneal cavity. Though the extraembryonic yolk sac is the first site of primitive red blood cell, megakaryocyte, and macrophage production, it is controversial whether it is a site of B lymphoid emergence. An intraembryonic site, the aorta-gonad-mesonephros (AGM) region derived from the P-Sp, is currently recognized as the first site of production of HSCs capable of repopulating the hematopoietic compartment of lethally irradiated adult mice and is reported to possess the potential to give rise to B lymphoid cells upon in vitro co-culture with a certain stromal cell line. However, after the systemic circulation has commenced, it remains unclear and unproven whether the B cell progenitors are moving from the yolk sac into the P-Sp or vice versa. Indeed, the most formidable obstacle encountered when attempting to define the onset of B lymphopoiesis in the developing murine embryo, is the onset of cardiac contractions and establishment of the circulation. We have developed a novel approach that permits determination of exactly where and when hematopoietic cells emerge in the yolk sac and P-Sp. Ncx1 encodes a sodium-calcium exchange protein that is expressed only in cardiomyocytes through embryonic day (E) 11.0. Embryos lacking Ncx1 are unable to initiate cardiac contractions preventing the onset of the systemic circulation. Lack of blood flow is initially tolerated without evidence of maldevelopment, however embryos demonstrate growth retardation by E10.0 and die by E11.0. Using Ncx1 mutant and wild type (WT) mice, we have recently reported that all hematopoietic definitive progenitor cells that seed the E 10.0 fetal liver are yolk sac-derived. We have also reported that the potential for forming B lymphoid cells is present in the E 9.5 yolk sac and P-Sp of wild type and Ncx1 null mice; confirming that B lymphoid cells arise autonomously in the yolk sac and P-Sp. A host of questions now emerge that we address in the following aims: Aim 1: To delineate the temporal and spatial emergence of B lymphoid cells in the yolk sac and P-Sp and to define B cell specification to B1 and/or B2 lymphoid lineages from the emergent cells in these sites. Aim 2: To define the growth factor signaling pathways required for yolk sac and P-Sp B lymphopoiesis. Aim 3: Define the molecular pathway for yolk sac and P-Sp derived B cell homing to the peritoneal cavity. These studies will define the mechanism of B lymphocyte emergence, determine whether differences in B cell specification are intrinsic and restricted, and may clarify the origin of the B1 lymphocytes that secrete natural antibodies; a population of cells important in human development of autoimmune diseases and leukemia. PUBLIC HEALTH RELEVANCE: This project aims to determine the factors required to permit the emergence of B lymphoid cells in the murine yolk sac and within the embryo and to define the molecules that are necessary for yolk sac and intraembryonic B lymphoid cells to home to the peritoneal cavity.

描述（由申请人提供）：本工作的总体目标是确定允许 B 淋巴细胞在胚胎外卵黄囊和主动脉旁内脏胸膜 (P-Sp) 中出现并促进这些细胞归巢到腹膜腔的机制。虽然胚胎外卵黄囊是原始红细胞、巨核细胞和巨噬细胞产生的最初场所，但它是否是B淋巴细胞出现的场所尚存在争议。胚胎内位点，即源自 P-Sp 的主动脉-性腺-中肾 (AGM) 区域，目前被认为是 HSC 生产的第一个位点，能够重新填充受致死照射的成年小鼠的造血室，并且据报道具有在与某种基质细胞系体外共培养时产生 B 淋巴细胞的潜力。然而，在体循环开始后，B 细胞祖细胞是否从卵黄囊移至 P-Sp 或反之亦然，仍不清楚且未经证实。事实上，在试图确定发育中的小鼠胚胎中 B 淋巴细胞生成的开始时遇到的最可怕的障碍是心脏收缩的开始和循环的建立。我们开发了一种新方法，可以准确确定造血细胞在卵黄囊和 P-Sp 中出现的位置和时间。 Ncx1 编码钠钙交换蛋白，仅在胚胎日 (E) 11.0 的心肌细胞中表达。缺乏 Ncx1 的胚胎无法启动心脏收缩，从而阻止体循环的发生。最初可以容忍血流不足，没有发育不良的证据，但胚胎在 E10.0 时表现出生长迟缓，并在 E11.0 时死亡。使用 Ncx1 突变型和野生型 (WT) 小鼠，我们最近报道，接种 E 10.0 胎肝的所有造血祖细胞都是卵黄囊来源的。我们还报道，野生型和 Ncx1 缺失小鼠的 E 9.5 卵黄囊和 P-Sp 中存在形成 B 淋巴细胞的潜力；证实 B 淋巴细胞在卵黄囊和 P-Sp 中自主产生。现在出现了许多问题，我们要解决以下目标： 目标 1：描绘卵黄囊和 P-Sp 中 B 淋巴细胞的时间和空间出现，并从这些位点的出现细胞中定义 B 细胞特异为 B1 和/或 B2 淋巴谱系。目标 2：确定卵黄囊和 P-Sp B 淋巴细胞生成所需的生长因子信号通路。目标 3：确定卵黄囊和 P-Sp 衍生 B 细胞归巢至腹膜腔的分子途径。这些研究将明确B淋巴细胞出现的机制，确定B细胞规格的差异是否是内在的和限制性的，并可能澄清分泌天然抗体的B1淋巴细胞的起源；在人类自身免疫性疾病和白血病的发展中重要的细胞群。公共健康相关性：该项目旨在确定允许 B 淋巴细胞在小鼠卵黄囊和胚胎内出现所需的因素，并确定卵黄囊和胚胎内 B 淋巴细胞归巢至腹膜腔所需的分子。