Notch Signaling in Endochondral Bone Development

软骨内骨发育中的Notch信号传导

• 批准号: 9761983
• 负责人: Matthew J. Hilton
• 金额: $ 35.42万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9761983
• 关键词: Adipocytes; Apoptosis; Biological Assay; Biology; Blood Vessels; Bone Development; Bone Marrow; Bone Matrix; Bone Regeneration; Cartilage; Cartilage Matrix; Cell Therapy; Cells; Chondrocytes; Clone Cells; Data; Development; Epiphysial cartilage; Excision; Exhibits; Freezing; Generations; Genes; Genetic; Genetic Models; Genotype; Goals; Histology; In Vitro; Invaded; Label; Mediating; Mesenchymal; Molecular; Mus; Orthopedics; Osteoblasts; Osteogenesis; Outcome Measure; Paraffin; Pathway interactions; Physiologic Ossification; Play; Population; Process; Regenerative Medicine; Regulation; Role; Signal Transduction; Stains; Stem cells; System; Therapeutic; Tissues; Work; base; bone; cartilage cell; cell type; experimental study; gain of function; in vivo; loss of function; microCT; notch protein; novel; novel strategies; osteoblast differentiation; osteogenic; overexpression; progenitor; recruit; skeletal; skeletal disorder; stem; transcriptome sequencing; transdifferentiation

PROJECT SUMMARY: A primary function of growth plate cartilage is to support bone formation and elongation during endochondral ossification. Growth plate chondrocytes undergo rapid proliferation and matrix synthesis followed by hypertrophic differentiation. Hypertrophic chondrocytes secrete various factors that degrade the cartilage matrix, recruit vascular cells and osteoblast progenitors, and promote the differentiation of osteoblasts responsible for new bone formation. Dogma dictates that hypertrophic chondrocytes ultimately undergo apoptosis to facilitate removal of the cartilage template that is eventual replaced by bone. Recent cartilage-specific lineage tracing studies have suggested that terminal hypertrophic chondrocytes are capable of directly differentiating into mature osteoblasts during bone formation and repair via a process known as transdifferentiation. However, our preliminary data suggests that at least a subset of terminal hypertrophic chondrocytes undergo dedifferentiation to generate bone marrow mesenchymal stem/progenitor cells (BMSCs) capable of differentiating into various mature cell types including: osteoblasts and adipocytes. Since almost nothing is known about this process, our long-term goal is to identify the cellular and molecular mechanism(s) that regulate hypertrophic chondrocyte dedifferentiation during endochondral bone formation. Using a variety of sophisticated mouse genetic models and in vitro systems, we aim to: (Aim 1) identify whether hypertrophic chondrocytes dedifferentiate to form a molecularly and functionally distinct population of multipotent BMSCs, (Aim 2) determine whether NOTCH signaling in hypertrophic chondrocytes is necessary and/or sufficient to promote chondrocyte dedifferentiation during endochondral bone formation, and (Aim 3) establish whether SOX2 is an important regulator of hypertrophic chondrocyte dedifferentiation and a target of NOTCH signaling in the regulation of this process. Completion of these aims will have broad implications in skeletal biology by elucidating fundamental cellular and molecular mechanisms associated with the novel process of hypertrophic chondrocyte dedifferentiation during endochondral ossification. This work will also aid our understanding of NOTCH-related skeletal diseases, as well as, set the stage for developing novel approaches for the ex vivo generation of mesenchymal stem/progenitors from cartilage for use in regenerative medicine or cell therapeutic applications.

项目概要： 生长板软骨的主要功能是在软骨内生长期间支持骨形成和延长 骨化生长板软骨细胞经历快速增殖和基质合成，然后肥大， 分化肥大的软骨细胞分泌各种因子，降解软骨基质，募集血管， 细胞和成骨细胞祖细胞，并促进负责新骨形成的成骨细胞的分化。 理论上，肥大的软骨细胞最终会发生凋亡，以促进软骨的去除 最终被骨骼取代的模板。最近的软骨特异性谱系追踪研究表明， 终末肥大软骨细胞能够在成骨过程中直接分化为成熟成骨细胞， 形成和修复的过程称为转分化。然而，我们的初步数据表明，至少 终末肥大软骨细胞的亚群经历去分化以产生骨髓间充质干细胞， 干/祖细胞（BMSC）能够分化成各种成熟细胞类型，包括：成骨细胞和 脂肪细胞由于对这一过程几乎一无所知，我们的长期目标是确定细胞和 软骨内成骨过程中肥大软骨细胞去分化的分子调控机制 阵使用各种复杂的小鼠遗传模型和体外系统，我们的目标是：（目标1）鉴定 肥大软骨细胞是否去分化形成分子和功能上不同的 多能BMSC，（目的2）确定肥大软骨细胞中的NOTCH信号传导是否是必需的和/或 足以促进软骨内骨形成过程中软骨细胞的去分化，以及（目的3）确定是否 SOX 2是肥大软骨细胞去分化的重要调节因子，也是软骨细胞增殖中NOTCH信号传导的靶点。 规范这个过程。这些目标的完成将在骨骼生物学中产生广泛的影响， 与肥大软骨细胞的新过程相关的基本细胞和分子机制 软骨内骨化过程中的脱分化。这项工作也将有助于我们了解NOTCH相关的骨骼肌 疾病，以及，为开发用于离体产生间充质干细胞的新方法奠定了基础。 用于再生医学或细胞治疗应用的来自软骨的干/祖细胞。