FunctionalCharacterization of the Stem Cell Niche

干细胞生态位的功能表征

• 批准号: 7740043
• 负责人: Paul Hugo Krebsbach
• 金额: $ 35.25万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7740043
• 关键词: Acute; Address; Animals; Automobile Driving; Biological Models; Biology; Bone Marrow; Bone Regeneration; CD15 Antigens; Cell Communication; Cell Count; Cell Culture Techniques; Cell Differentiation process; Cell Separation; Cell physiology; Cell surface; Cells; Complex; Cultured Cells; Data; Development; Developmental Biology; Dissection; Dose; Environment; Environmental Risk Factor; Exhibits; Family; Figs - dietary; Fluorouracil; Gelatin; Goals; Harvest; Hematology; Hematopoietic stem cells; Hemorrhage; Immunohistochemistry; Immunophenotyping; Implant; In Vitro; Learning; Left; Life; Maps; Marrow; Mediating; Mesenchymal; Mesenchymal Stem Cells; Methods; Modeling; Monitor; Mononuclear; Mus; Nature; Osteoblasts; Osteogenesis; Pathologic; Phenotype; Physiological; Plastics; Pluripotent Stem Cells; Population; Principal Investigator; Process; Property; Research Personnel; Stem Cell Factor; Stem cells; Stimulus; Stress; Stromal Cells; System; Testing; Time; Tissue Engineering; Transgenic Organisms; Transplantation; acute stress; base; bone; bone morphogenetic protein 2; bone morphogenetic protein 6; cell type; design; flexibility; in vivo; in vivo Bioassay; in vivo Model; innovation; osteoblast differentiation; programs; prospective; public health relevance; reconstitution; response; scaffold; stem cell differentiation; stem cell fate; stem cell niche; stem cell population; subcutaneous; tool

DESCRIPTION (provided by applicant): We identified a partially purified mesenchymal stem cell (MSC) population that maintains its multi-lineage potential both in vivo and in vitro. Most importantly, we demonstrated that as few as 500 purified cells can develop bone in vivo without prior cell expansion in culture. This prospective isolation process, based upon lessons learned from hematology, sets us apart from others in the mesenchymal biology field and will allow us to understand the crucial differences in stem cell properties between cell culture and in vivo environments. The overall objective of this application is to understand the biology of this stem cell population, including in vivo lineage progression, how they function in the stem cell niche and determine the functional relationships and crosstalk between HSCs and MSCs. The central hypothesis behind our proposed projects is that a true mesenchymal stem cell exists within the bone marrow and the activity of this stem cell, including interactions with HSCs, is dependent on its niche compartment. We plan to test our central hypothesis and accomplish our objectives by pursuing three specific aims. Each aim offers the opportunity to generate new tools that will revolutionize the ability to discover and model the environmental factors that mediate cell function in complex in vivo systems such as the bone/bone marrow. Aim 1. To identify and characterize cells within the bone marrow stroma that exhibit mesenchymal stem cell activity. We will answer the following compelling questions: 1) Do these purified cells function as stem cells in vivo? 2) What is the capacity of these purified cells to function in their native in vivo micro-environment? and 3) How do MSCs respond to physiologic stimuli? Aim 2. To identify the MSC niche and determine the extent to which the MSC pool and its niche changes under physiologic and pathologic conditions (Mapping and defining the niche). We will address the following experimental questions 1) Where do MSCs reside within the marrow? 2) Do MSC numbers change in response to physiologic and or pathologic stimuli, including a single dose of 5-FU, a single acute bleed and anabolic PTH treatment? 3) Do perturbations of the marrow alter/regulate the MSC phenotype? Aim 3. To determine the functional relationships and cross talk between HSCs and MSCs. 1) Do MSCs and HSCs co-localize to the same niche? 2) Do HSCs (isolated with SLAM family markers) regulate MSC fate? PUBLIC HEALTH RELEVANCE: A fundamental question in cellular and developmental biology is how a stem cell niche develops, and how these niches support and maintain stem cell activity. We have pioneered the use of an in vivo model that we will now use to functionally characterize our prospectively isolated MSCs. Our projects are designed to understand the nature of these MSCs and how their microenvironment, including interactions with hematopoietic stem cells (HSCs), influences their biologic activity. The overall hypothesis driving our project is that a true mesenchymal stem cell exists within the bone marrow and the activity of this stem cell - including interactions with hematopoietic stem cells - is dependent on its niche compartment.

描述（由申请人提供）：我们鉴定了部分纯化的间充质干细胞（MSC）群体，其在体内和体外均保持其多谱系潜力。最重要的是，我们证明了只有500个纯化的细胞可以在体内发育成骨，而无需在培养中进行细胞扩增。这种前瞻性的分离过程，基于血液学的经验教训，使我们在间充质生物学领域与其他人区分开来，并使我们能够了解细胞培养和体内环境之间干细胞特性的关键差异。本申请的总体目标是了解该干细胞群体的生物学，包括体内谱系进展，它们如何在干细胞生态位中发挥作用，并确定HSC和MSC之间的功能关系和串扰。我们提出的项目背后的核心假设是，骨髓中存在真正的间充质干细胞，这种干细胞的活性，包括与HSC的相互作用，取决于其生态位隔室。我们计划通过追求三个具体目标来检验我们的中心假设并实现我们的目标。每个目标都提供了产生新工具的机会，这些工具将彻底改变发现和模拟在复杂的体内系统（如骨/骨髓）中介导细胞功能的环境因素的能力。目标1.鉴定和表征骨髓基质中表现出间充质干细胞活性的细胞。我们将回答以下引人注目的问题：1）这些纯化的细胞在体内是否具有干细胞的功能？2)这些纯化的细胞在其天然的体内微环境中发挥功能的能力是什么？3）MSCs对生理刺激的反应如何？目标2.确定MSC生态位，并确定MSC池及其生态位在生理和病理条件下的变化程度（定位和定义生态位）。我们将解决以下实验问题1）MSC在骨髓中的位置？2)MSC数量是否会因生理和/或病理刺激而改变，包括单剂量5-FU、单次急性出血和合成代谢PTH治疗？3)骨髓的扰动改变/调节MSC表型吗？目标3。目的探讨HSC与MSCs之间的功能关系及相互作用。1)MSC和HSC是否共定位于相同的生态位？2)HSC（分离SLAM家族标志物）调节MSC命运吗？公共卫生相关性：细胞和发育生物学中的一个基本问题是干细胞小生境如何发育，以及这些小生境如何支持和维持干细胞活性。我们已经率先使用体内模型，我们现在将使用它来功能性地表征我们的前瞻性分离的MSC。我们的项目旨在了解这些MSC的性质以及它们的微环境，包括与造血干细胞（HSC）的相互作用，如何影响它们的生物活性。驱动我们项目的总体假设是，真正的间充质干细胞存在于骨髓中，并且这种干细胞的活性-包括与造血干细胞的相互作用-取决于其生态位隔室。