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: 10686056
• 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/10686056
• 关键词: 3-Dimensional; ALCAM gene; Adult; Age; Blood Cells; Blood Platelets; Blood coagulation; Bone Marrow; Calvaria; Cell Maintenance; 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; Macrophage; Maintenance; Malignant Neoplasms; Marrow; Mediating; Megakaryocytes; Modeling; Molecular; Mus; National Institute of Diabetes and Digestive and Kidney Diseases; Neonatal; Osteoblasts; PF4 Gene; PTPRC gene; Pathway interactions; Phenotype; Population; Property; Proteomics; Publishing; Radiation; Regulation; Research; Role; Signal Transduction; Structure; Surface; Testing; Time; Tissues; Transforming Growth Factors; Transplantation; Work; cell preparation; cell type; conditioning; hematopoietic stem cell differentiation; hematopoietic stem cell niche; hematopoietic stem cell self-renewal; in vivo; long bone; mature animal; osteoblast differentiation; osteoblast proliferation; progenitor; programs; recruit; spatial relationship; stem cell engraftment; stem cell function; stem cells; 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.

造血生态位是多种细胞类型和细胞外基质蛋白的复杂结构。在 精心策划的方式，利基的元素一起相互作用，与造血干细胞（HSC）相互作用 保持HSC自我企业潜力。骨髓（BM）内的HSC维护与 小众细胞元素的健康，包括内皮细胞，成骨细胞和其他造血细胞 例如巨核细胞。我们发表的作品表明，未成熟的成骨细胞可以调解一种强大的 体外造血增强活性，巨核细胞增强成骨细胞增殖并抑制 他们的差异。巨核细胞与调节HSC功能和维持 辐射后，通过与成骨细胞相互作用的辐射能力 HSC功能的增强。最近，CD45+ F4/80+巨噬细胞的独特种群称为 在利基市场中认可骨瘤（OM）。我们检测到新生儿钙细胞（NCC）中的这些细胞 准备工作，最近发表的说明OM对于增强成骨细胞介导的造血至关重要 活动。巨核细胞刺激NCC衍生的OM以及成年小鼠的OM，并显着增强 他们的体外扩张和功能。有趣的是，OM的广泛流式细胞术表征显示 OM在表型上与BM衍生的巨噬细胞不同，后来无法在功能上 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 表明OM对于造血生态位的能力很重要。我们假设这一点 HSC功能的维持和造血生态位的能力取决于 细胞相互作用和成骨细胞，OM和巨核细胞之间的分子交叉说法。我们的 假设将通过研究以下三个目的来检查假设：1）调查OM是否可以移植 以及巨核细胞的损失是否会破坏OM的出现，并对HSC功能产生负面影响 利基能力。 2）确定OM和BM衍生的巨噬细胞之间的差异，这些巨噬细胞使OM成为独特 利基组分并在分子层定义OM和巨核细胞如何促进维持 HSC功能。 3）定义HSC，成骨细胞，OM和巨核细胞之间的空间关系 在骨髓调理后，年轻小鼠和老鼠的完整小阵列以及在扰动的微环境中。这 这些研究的重要性是它们将定义和解释四个细胞之间的相互作用 BM的组成部分调节HSC功能和利基的能力。新颖性源于 这些研究的潜力是首次建立独特的细胞，即OM作为主要靶标 巨核细胞介导的HSC促进利基的活性。我们的前提是OM是HSC的核心 利基的功能属性都是我们对我们对之间紧密相互作用之间紧密相互作用的范式的转移 HSC和利基市场也是一种未开发的途径，对维持造血的途径至关重要。