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: 8214496
• 负责人: IVO Kalajzic
• 金额: $ 34.39万
• 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/8214496
• 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. PUBLIC HEALTH RELEVANCE: The aims of this application are focused to better identification and characterization of adult mesenchymal progenitor cells. Our study will evaluate their ability to differentiate into mature mesenchymal lineages in vitro and in vivo and determine the diverging point at which mesenchymal progenitor cells commit to mature lineages and factors that can modulate this commitment. The knowledge developed in this grant will provide the foundation for future studies aimed at use of mesenchymal progenitor cells as therapeutic tools for osteoporosis and genetic disorders of bone.

描述（由申请人提供）：成年间充质祖细胞具有巨大的用于修复医学的潜力。骨髓抽吸物或吸脂收集的易于获取和分离使这些细胞成为研究各种成年间充质组织的研究的主要目标。如果这种祖细胞的来源是实现广泛的临床实用性，那么祖细胞的真实身份及其后代需要更精确地定义，并且需要理解其承诺的调节。这些目标的障碍是无法识别和净化这些细胞，并且缺乏可用于确认祖细胞可以达到终极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，该假设将测试周细胞/成肌纤维细胞是否具有间充质祖细胞的特征。我们假设平滑肌A-肌动蛋白（SMA）表达细胞是成年骨组织中骨基因生成剂的主要来源。为了定义肌纤维细胞/周细胞的种群，我们将利用先前开发的转基因小鼠，其中通过SMA启动子GFP转基因表达（SMAGFP）鉴定出周细胞。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定启动子驱动GFP报告基因表达。这些转基因在谱系的成熟阶段激活，通过结合互补的颜色，我们可以测试孤立的SMA+细胞从祖细胞发展到完全成熟状态的能力。此外，我们将使用体内的再生模型和新的骨形成完成谱系追踪实验。在组织修复模型中，利用与ROSA26（CAG-TDTOMATO）记者线交叉的SMA-Creert2小鼠，包括使用BMP2诱导的异位骨形成的骨折愈合和诱导骨势的诱导，我们将评估SMA表达细胞的祖细胞能力。在第三个目的中，我们建议确定间充质祖细胞的差异点到成熟的谱系中。基于谱系指导的GFP标记的表达，将分离出间充质祖细胞的特定阶段特定种群，并将测试其分化能力。定义分化的控制将允许理解将间充质干细胞引导到骨基源谱系的机制。拟议研究的完成将更好地理解间充质祖细胞的身份和表型，并提供有关其在损伤和骨折期间骨骼愈合中的积极作用的信息。 公共卫生相关性：本应用的目的是更好地识别和表征成人间充质祖细胞。我们的研究将评估它们在体外和体内区分成熟间充质谱系的能力，并确定间充质祖细胞致力于成熟的谱系和可以调节这种承诺的因素的分化点。该赠款中发展的知识将为未来的研究提供基础，旨在将间充质祖细胞用作骨质疏松症和骨骼遗传疾病的治疗工具。