Defining a myofibroblast/pericyte as a mesenchymal progenitor cell

将肌成纤维细胞/周细胞定义为间充质祖细胞

• 批准号: 8442384
• 负责人: IVO Kalajzic
• 金额: $ 32.66万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8442384
• 关键词: Ablation; Actins; Adipocytes; Adipose tissue; Adult; Aspirate substance; BMP2 gene; Bone Marrow; Bone Regeneration; Bone Tissue; Breeding; Cells; Characteristics; Chondrocytes; Clinical; Collagen; Collection; Color; Commit; Development; Exhibits; Experimental Models; FGF2 gene; Fluorescence-Activated Cell Sorting; Foundations; Fracture; Fracture Healing; Future; Ganciclovir; Gel; Goals; Grant; Hereditary Disease; Human; In Vitro; Injury; Knowledge; Label; Measures; Mesenchymal; Mesenchymal Stem Cells; Modeling; Mus; Myofibroblast; Natural regeneration; Osteoblasts; Osteogenesis; Osteoporosis; Pericytes; Phenotype; Population; Regenerative Medicine; Reporter; Research; Role; Signal Pathway; Smooth Muscle; Source; Staging; Stem cells; Stromal Cells; Suction Lipectomy; Tamoxifen; Testing; Therapeutic; Tissues; Transcription Factor AP-2 Alpha; Transgenes; Transgenic Mice; Transgenic Model; Transplantation; alpha Actin; base; bone; bone healing; in vitro testing; in vivo; in vivo Model; inhibitor/antagonist; mouse model; osteogenic; osteoprogenitor cell; progenitor; promoter; public health relevance; recombinase; regenerative; reparative medicine; research study; tissue repair; tool; transgene expression; translational study

DESCRIPTION (provided by applicant): Adult mesenchymal progenitor cells have enormous potential for use in reparative medicine. The easy access and isolation of bone marrow aspirate or liposuction collection have made these cells a prime target for studies of differentiation into various adult mesenchymal tissues for regenerative purposes. If this source of progenitor cells is to achieve broad clinical utility, the true identity of the progenitors and its progeny need to be more precisely defined and modulation of their commitment needs to be understood. Obstacles to these goals are the inability to identify and purify these cells, and the lack of in vivo markers that can be used to confirm that progenitor cells can attain the state and functionality of terminally differentiated phenotypes. We accept these challenges and propose a hypothesis that will test if pericyte/myofibroblasts have the characteristics of mesenchymal progenitors. We hypothesize that smooth muscle a-actin (SMA) expressing cells are the major source of osteoprogenitors in adult bone tissue. To define a population of myofibroblasts/pericytes we will utilize previously developed transgenic mice in which pericytes are identified by SMA promoter-GFP transgene expression (SMAGFP). The differentiation ability of these cells, will be tested using transgenic mice in which osteoblast, adipocyte or chondrocyte specific promoters drive GFP reporter expression. These transgenes activate at mature stages of the lineage and, by combining complementary colors, we can test for the ability of isolated SMA+ cells to progress from a progenitor to fully mature state. In addition we will complete lineage tracing experiments using regeneration models and new bone formation in vivo. Utilizing an SMA-CreERT2 mouse crossed with a Rosa26(cag-tdTomato) reporter line in models of tissue repair that include fracture healing and induction of osteogenic potential using ectopic bone formation induced by BMP2, we will evaluate the progenitor ability of SMA expressing cells. In the third aim we propose to determine the divergence point of mesenchymal progenitor cell into mature lineages. Based on expression of lineage-directed GFP markers, stage specific populations of mesenchymal progenitors will be isolated and their differentiation ability will be tested. Defining the control of differentiation will allow for the understanding of the mechanisms that direct mesenchymal stem cells down the osteoprogenitor lineage. Completion of the proposed studies will provide a better understanding of the identity and the phenotype of the mesenchymal progenitor cells as well as provide information on their active role in bone healing during injury and bone fractures.

描述（由申请人提供）：成体间充质祖细胞在修复医学中具有巨大的应用潜力。骨髓抽吸或抽脂收集的容易获取和分离使这些细胞成为研究分化为各种成人间充质组织以用于再生目的的主要目标。如果这种祖细胞来源要实现广泛的临床用途，则需要更精确地定义祖细胞及其后代的真实身份，并需要了解它们的承诺的调节。这些目标的障碍是无法识别和纯化这些细胞，并且缺乏可用于确认祖细胞可以获得终末分化表型的状态和功能的体内标记。我们接受这些挑战并提出一个假设来测试周细胞/肌成纤维细胞是否具有间充质祖细胞的特征。我们假设平滑肌α-肌动蛋白（SMA）表达细胞是成人骨组织中骨祖细胞的主要来源。为了定义肌成纤维细胞/周细胞群体，我们将利用先前开发的转基因小鼠，其中周细胞通过 SMA 启动子-GFP 转基因表达 (SMAGFP) 进行识别。这些细胞的分化能力将使用转基因小鼠进行测试，其中成骨细胞、脂肪细胞或软骨细胞特异性启动子驱动GFP报告基因表达。这些转基因在谱系的成熟阶段激活，通过结合互补色，我们可以测试分离的 SMA+ 细胞从祖细胞发展到完全成熟状态的能力。此外，我们将使用再生模型和体内新骨形成来完成谱系追踪实验。在组织修复模型中利用 SMA-CreERT2 小鼠与 Rosa26(cag-tdTomato) 报告系杂交，包括骨折愈合和使用 BMP2 诱导异位骨形成诱导成骨潜力，我们将评估 SMA 表达细胞的祖细胞能力。在第三个目标中，我们建议确定间充质祖细胞分化为成熟谱系的分歧点。基于谱系定向 GFP 标记的表达，将分离阶段特定的间充质祖细胞群体并测试其分化能力。定义分化的控制将有助于理解引导间充质干细胞沿骨祖细胞谱系向下的机制。完成拟议的研究将有助于更好地了解间充质祖细胞的身份和表型，并提供有关它们在损伤和骨折期间骨愈合中的积极作用的信息。