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

基本信息

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
项目类别：
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

项目摘要

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。在一个以精心策划的方式，生态位的各个元素相互作用并与造血干细胞（HSC）相互作用，以维持 HSC 自我更新潜力。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比如巨核细胞。我们发表的工作表明，未成熟的成骨细胞介导了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化。巨核细胞参与调节 HSC 功能和维持辐射后通过与成骨细胞的专门相互作用增强其能力增强 HSC 功能。最近，一个独特的 CD45+F4/80+ 巨噬细胞群被称为 osteomacs (OM) 在利基市场中得到了认可。我们在新生儿颅盖细胞 (NCC) 中检测到这些细胞制剂和最近发表的 OM 对于成骨细胞介导的造血增强至关重要活动。巨核细胞刺激 NCC 衍生的 OM 以及成年小鼠的 OM，并显着增强它们的体外扩增和功能。有趣的是，OM 的广泛流式细胞术表征揭示了 OM 在表型上与 BM 衍生的巨噬细胞不同，并且后者不能发挥功能替代 OM 驱动成骨细胞介导的造血增强活性。我们的研究进一步表明 OM 对于造血生态位的能力很重要。我们假设 HSC 功能的维持和造血生态位的能力取决于成骨细胞、OM 和巨核细胞之间的细胞相互作用和分子串扰。我们的将通过调查以下三个目标来检验假设：1）调查 OM 是否可移植巨核细胞的丧失是否会破坏 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 衍生巨噬细胞之间的差异，这些差异使 OM 成为独特的巨噬细胞生态位成分，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）定义HSC、成骨细胞、OM和巨核细胞之间的空间关系年轻和年老小鼠的完整生态位以及骨髓调理后扰动的微环境。这这些研究的意义在于，它们将定义并解释四种细胞之间的相互作用如何 BM 的组成部分调节 HSC 功能和生态位的能力。新颖性来源于这些研究有潜力首次建立一组独特的细胞，即 OM，作为主要目标巨核细胞介导的 HSC 在生态位中的促进活性。我们的前提是 OM 是 HSC 的核心和利基功能特性都在我们理解两者之间密切相互作用的过程中发生了范式转变。 HSC 和利基也是一条未探索的对于维持造血功能至关重要的途径。