Characterization of the first HSCs during mouse ontogeny

小鼠个体发育过程中第一个 HSC 的表征

• 批准号: 7142266
• 负责人: ELAINE A DZIERZAK
• 金额: $ 20.72万
• 依托单位: ERASMUS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7142266
• 关键词: Mus musculus; aorta; bone marrow; bone morphogenetic proteins; cell differentiation; cell migration; cell population study; cell transplantation; developmental genetics; early embryonic stage; embryogenesis; genetically modified animals; gonads; green fluorescent proteins; hematopoiesis; hematopoietic growth factor; hematopoietic stem cells; interleukin 3; mammalian embryology; technology /technique development; transcription factor; vascular endothelium

DESCRIPTION (provided by applicant): The continuous life-long production of all mature blood cells in the circulation and hematopoietic tissues is contingent on hematopoietic stem cells (HSC). These rare cells reside in the bone marrow of the adult and are the clinically important cells in transplantation therapies for blood-related diseases and leukemias. The manipulation of limited numbers of adult HSCs has been difficult, since ex vivo expansion of these cells has not yet been achieved. Despite the identification and use of many hematopoietic growth factors, HSCs can at best be maintained, not expanded. We hypothesized that at some early stage in ontogeny HSCs are generated and expanded in a unique embryonic microenvironment. An understanding of the developmental processes leading to HSC emergence in the embryo should provide novel insights and improved methods for the ex vivo expansion of HSCs for clinical use. To this end, our long-term research objective has been to determine the cellular and molecular mechanisms by which HSCs are generated/expanded within the mammalian embryo. We have shown that the mouse aorta-gonad-mesonephros (AGM) region autonomously generates the first fully potent HSCs in close association with the aortic endothelium. We have demonstrated that Runx1 and GATA-2 transcription factors are required for the generation and expansion of these HSCs. However, more factors have yet to be identified. In various preliminary studies of the AGM microenvironment, IL-3, BMP-4 and hedgehog factors have been implicated as effectors of AGM HSC emergence, but these factors must be further characterized. Thus, we will examine each factor for its role in the induction and expansion of HSCs in the midgestation mouse aorta. Using classical embryologic methods, we will deliver factors to whole cultured mouse embryos by bead/cell pellet implantation and transgenesis, to determine their effect on AGM HSCs. In similar factor manipulation experiments, we aim to establish the lineage relationships of precursors to AGM HSCs by dye marking of aortic endothelium. We will also investigate the long-term fate of the HSCs generated in the mouse AGM by Cre-lox recombination technology. If indeed embryonic aorta-derived HSCs migrate and colonize the adult bone marrow, our insights into their generation and expansion should lead to novel methods for clinical HSC expansion and thus, improve transplantation therapies.

描述（由申请人提供）：循环和造血组织中所有成熟血细胞的持续终生产生取决于造血干细胞（HSC）。这些稀有细胞存在于成人的骨髓中，是血液相关疾病和白血病移植治疗中临床上重要的细胞。有限数量的成体造血干细胞的操作一直很困难，因为这些细胞的离体扩增尚未实现。尽管鉴定和使用了许多造血生长因子，但造血干细胞最多只能维持，而不是扩增。我们假设在个体发育的某些早期阶段，HSC 在独特的胚胎微环境中生成和扩增。对胚胎中 HSC 出现的发育过程的了解应该为临床使用的 HSC 体外扩增提供新的见解和改进的方法。为此，我们的长期研究目标是确定 HSC 在哺乳动物胚胎内生成/扩增的细胞和分子机制。我们已经证明，小鼠主动脉-性腺-中肾 (AGM) 区域自主生成第一个与主动脉内皮密切相关的全效 HSC。我们已经证明 Runx1 和 GATA-2 转录因子是这些 HSC 的生成和扩增所必需的。然而，更多因素仍有待确定。在 AGM 微环境的各种初步研究中，IL-3、BMP-4 和刺猬因子被认为是 AGM HSC 出现的效应因子，但这些因素必须进一步表征。因此，我们将检查每个因素在妊娠中期小鼠主动脉中 HSC 的诱导和扩增中的作用。使用经典的胚胎学方法，我们将通过珠子/细胞颗粒植入和转基因将因子传递到整个培养的小鼠胚胎，以确定它们对 AGM HSC 的影响。在类似的因子操纵实验中，我们的目标是通过主动脉内皮的染料标记来建立 AGM HSC 前体的谱系关系。我们还将研究通过 Cre-lox 重组技术在小鼠 AGM 中生成的 HSC 的长期命运。如果胚胎主动脉来源的 HSC 确实能够迁移并定植于成人骨髓中，那么我们对其生成和扩增的深入了解应该会带来临床 HSC 扩增的新方法，从而改善移植疗法。