Osteomacs and megakaryocytes interact to regulate hematopoietic stem cell function

骨巨细胞和巨核细胞相互作用调节造血干细胞功能

• 批准号: 9764740
• 负责人: Melissa A Kacena
• 金额: $ 31.7万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9764740
• 关键词: 3-Dimensional; ALCAM gene; Adult; Age; Blood Cells; Blood Platelets; Blood coagulation; Bone Marrow; Calvaria; Cell Maintenance; Cell physiology; Cells; Clinical Treatment; Competence; Complex; Critical Pathways; Cytometry; Data; Development; Elements; Embryo; Endosteum; Endothelial Cells; Engraftment; Erythropoiesis; Extracellular Matrix Proteins; Funding Opportunities; Genetic Models; Genomics; Goals; Health; Hematopoiesis; Hematopoietic; Hematopoietic Stem Cell Mobilization; Hematopoietic stem cells; In Vitro; Ionizing radiation; Lead; Maintenance; Malignant Neoplasms; Marrow; Mediating; Megakaryocytes; Modeling; Molecular; Mus; National Institute of Diabetes and Digestive and Kidney Diseases; Neonatal; Osteoblasts; PTPRC gene; Pathway interactions; Phenotype; Platelet Factor 4; Population; Property; Proteomics; Publishing; Radiation; Regulation; Research; Role; Signal Transduction; Stem cells; Structure; Surface; Testing; Time; Tissues; Transforming Growth Factors; Transplantation; Work; base; cell preparation; cell type; conditioning; hematopoietic stem cell niche; hematopoietic stem cell self-renewal; long bone; macrophage; mature animal; programs; recruit; spatial relationship; stem cell differentiation; transcriptome; transplant model

The hematopoietic niche is a complex structure of multiple cell types and extra-cellular matrix proteins. In a well-orchestrated manner, elements of the niche interact together and with hematopoietic stem cells (HSC) to maintain HSC selfrenewal potential. HSC maintenance within the bone marrow (BM) is associated with the health of cellular elements of the niche including endothelial cells, osteoblasts, and other hematopoietic cells such as megakaryocytes. Our published work demonstrates that immature osteoblasts mediate a robust in vitro hematopoiesis enhancing activity and that megakaryocytes enhance osteoblast proliferation and inhibit their differentiation. Megakaryocytes have been implicated in both regulating HSC function and maintaining the competence of the niche after radiation through specialized interactions with osteoblasts that augment their enhancement of HSC function. Recently, a unique population of CD45+F4/80+ macrophages known as osteomacs (OM) was recognized in the niche. We detected these cells in neonatal calvarial cell (NCC) preparations and recently published that OM are critical for the osteoblast-mediated hematopoiesis enhancing activity. Megakaryocytes stimulate NCC-derived OM as well as OM from adult mice and significantly enhance their in vitro expansion and function. Interestingly, extensive flow cytometric characterization of OM revealed that OM are phenotypically distinct from BM-derived macrophages and that the later cannot functionally substitute for OM to drive the osteoblast-mediated hematopoiesis enhancing activity. Our studies further suggest that OM are important for the competence of the hematopoietic niche. We hypothesize that maintenance of HSC function and the competence of the hematopoietic niche are dependent on cellular interactions and molecular cross talk between osteoblast, OM and megakaryocytes. Our hypothesis will be examined by investigating the following three aims: 1) Investigate if OM are transplantable and whether loss of megakaryocytes disrupts the emergence of OM and negatively impacts HSC function and niche competence. 2) Identify differences between OM and BM-derived macrophages that make OM a unique niche component and define, at the molecular level, how OM and megakaryocytes promote the maintenance of HSC function. 3) Define the spatial relationship between HSC, osteoblasts, OM, and megakaryocytes in the intact niche of young and old mice and in the perturbed microenvironment following marrow conditioning. The significance of these studies is that they will define and explain how the interplay between four cellular components of the BM regulate HSC function and the competence of the niche. The novelty derives from the potential of these studies to establish, for the first time, a unique group of cells, namely OM, as primary targets of the megakaryocyte-mediated HSC promoting activity in the niche. Our premise that OM are central to HSC and niche functional properties is both paradigm shifting in our understanding of the close interactions between HSC and the niche and is also an unexplored pathway critical to the maintenance of hematopoiesis.

造血生态位是由多种细胞类型和细胞外基质蛋白组成的复杂结构。在一个 在精心安排的方式下，利基的元素相互作用，并与造血干细胞(HSC)相互作用 保持HSC自我更新的潜力。骨髓(BM)内HSC的维持与 生态位细胞成分的健康状况，包括内皮细胞、成骨细胞和其他造血细胞 例如巨核细胞。我们发表的研究表明，未成熟的成骨细胞在 体外造血促进活性及巨核细胞促进成骨细胞增殖和抑制 它们的差异性。巨核细胞既参与调节HSC功能，又参与维持 放射后通过与成骨细胞的特殊相互作用增强成骨细胞的能力 增强肝星状细胞功能。最近，一组独特的CD45+F4/80+巨噬细胞被称为 骨肉瘤(OM)在壁龛中被发现。我们在新生儿颅骨细胞(NCC)中检测到这些细胞 研究和新近发表的OM在成骨细胞介导的造血促进中起关键作用 活动。巨核细胞刺激NCC来源的OM和成年小鼠的OM，并显著增强 它们的体外扩增和功能。有趣的是，OM的广泛的流式细胞术特征显示 OM在表型上不同于BM来源的巨噬细胞，后者在功能上不能 替代OM，驱动成骨细胞介导的造血增强活性。我们的研究进一步 提示OM对造血生态位的功能具有重要作用。我们假设 HSC功能的维持和造血生态位的能力依赖于 成骨细胞、OM和巨核细胞之间的细胞相互作用和分子串扰。我们的 假设将通过调查以下三个目的来检验：1)调查OM是否可移植 巨核细胞的丧失是否扰乱OM的出现，对HSC功能和 利基能力。2)确定OM和BM来源的巨噬细胞之间的差异，使OM成为一种独特的 并在分子水平上定义OM和巨核细胞如何促进维持 HSC功能。3)确定HSC、成骨细胞、OM和巨核细胞之间的空间关系 幼年和老年小鼠的完整生态位，以及骨髓调节后受扰的微环境。这个 这些研究的意义在于，它们将定义和解释四种细胞之间的相互作用 BM的成分调节HSC的功能和生态位的能力。这种新颖性来自于 这些研究首次建立了一组独特的细胞，即OM，作为主要目标的可能性 巨核细胞介导的肝星状细胞在利基体内的促进活性。我们认为OM是HSC的核心 和生态位功能属性都是我们理解两者密切互动的范式转变 HSC和NICE，也是一个未知的途径，对维持造血至关重要。