Role of Ossifying Chondrocytes in Regeneration of the Adult Jaw Skeleton

骨化软骨细胞在成人颌骨再生中的作用

• 批准号: 8620576
• 负责人: Gage D Crump
• 金额: $ 24.69万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-08-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8620576
• 关键词: Ablation; Address; Adopted; Adult; Amphibia; Amputation; Apoptosis; Body part; Bone Development; Bone Regeneration; Bone callus; Cartilage; Cells; Chondrocytes; Clinic; Data; Defect; Development; Employee Strikes; Fishes; Fracture; Future; Gene Expression; Genes; Genetic; Genetic Models; Genetic Techniques; Goals; Healed; Health; Human; Hybrid Cells; Hybrids; Hypertrophy; Immature Bone; Injury; Invaded; Jaw; Lead; Learning; Lesion; Limb structure; Lizards; Mammals; Mandible; Mature Bone; Mesenchymal; Modeling; Molecular; Molecular Profiling; Natural regeneration; Osteoblasts; Osteocytes; Pathway interactions; Patients; Periosteum; Physiological; Population; Property; Relative (related person); Role; Signal Transduction; Skeletal system; Skeleton; Source; Tail; Techniques; Testing; Transgenic Organisms; Vertebrates; Zebrafish; appendage; base; bone; cell behavior; healing; improved; injured; insight; mutant; novel; novel strategies; osteoblast differentiation; osteogenic; osteopontin; progenitor; programs; public health relevance; regenerative; repaired; response to injury; restoration; skeletal; skeletal injury; skeletal regeneration; tool

Project Summary/Abstract A major goal in human health is to improve the ability of large fractures and skeletal wounds to heal. In contrast to mammals, many amphibia and lizards do have a remarkable ability to reform entire limb and/or tail skeletons, yet the relative lack of genetic tools in these species have limited progress towards the underlying cellular and molecular mechanisms. Here, we present a new model of skeletal regeneration in the genetically tractable zebrafish. In a matter of just a few weeks, adult zebrafish can regenerate nearly two-thirds of their lower jawbone, and they appear to do so through an unusual chondrocyte population that directly produces woven bone. As potentially similar cells have been observed during mammalian fracture repair, a better understanding of these cells during skeletal repair, as well as how they contribute to more extensive regeneration in lower vertebrates, will aid in developing novel therapies for improving bone repair in patients. In the first aim, purification and expression profiling of regenerating chondrocytes, which express markers of both chondrocytes and osteoblasts, will determine the extent to which these cells are hybrid chondrocytes/ osteoblasts. Genes specifically upregulated in early regenerating chondrocytes will also indicate potential pathways that induce these cells in response to injury. Next, we use newly developed Cre/Lox transgenic lines to test the origins and long-term fate of regenerating chondrocytes. In particular, we test that the periosteum is a major source of regenerating chondrocytes, with these directly converting into the osteoblasts that produce woven bone. Using a novel intersectional transgenic strategy to specifically ablate regenerating chondrocytes, we then test that these cells are required for the large-scale regeneration of bone in the zebrafish jaw. During the development of endochondral bone, the majority of chondrocytes undergo hypertrophy and apoptosis, with bony matrix being produced by invading osteoblasts. Quite differently during regeneration, our preliminary data suggest that many chondrocytes directly differentiate into osteoblasts. Using an adult viable ihha mutant and a transgenic strategy to inhibit Hh signaling only in regenerating chondrocytes, we test in the second aim that persistently high Ihh signaling is essential for regenerating chondrocytes to differentiate into osteoblasts. The completion of these Aims will test a model that the ability of regenerating chondrocytes to directly make bone allows a rapid restoration of rigidity in a damaged body part, with the initial woven bone later being remodeled into mature bone. In the long-term, we plan to use lessons taken from this new zebrafish model to devise strategies to augment the inherent ability of the skeleton to repair critical size defects. !

项目概要/摘要 人类健康的一个主要目标是提高大面积骨折和骨骼伤口的愈合能力。相比之下 对于哺乳动物来说，许多两栖动物和蜥蜴确实具有改造整个肢体和/或尾巴的非凡能力 骨骼，但这些物种相对缺乏遗​​传工具，限制了潜在的进展 细胞和分子机制。在这里，我们提出了一种新的遗传性骨骼再生模型 易驯服的斑马鱼。在短短几周内，成年斑马鱼就可以再生近三分之二的身体 下颌骨，它们似乎是通过一种不寻常的软骨细胞群来做到这一点的，这种软骨细胞群直接产生 编织骨。由于在哺乳动物骨折修复过程中观察到了潜在的相似细胞，因此更好的方法 了解这些细胞在骨骼修复过程中的作用，以及它们如何促进更广泛的修复 低等脊椎动物的再生将有助于开发改善患者骨修复的新疗法。 第一个目标是再生软骨细胞的纯化和表达谱，这些细胞表达以下标记物： 软骨细胞和成骨细胞将决定这些细胞是混合软骨细胞/的程度 成骨细胞。在早期再生软骨细胞中特异性上调的基因也将表明潜在的潜力 诱导这些细胞对损伤作出反应的途径。接下来，我们使用新开发的Cre/Lox转基因品系 测试再生软骨细胞的起源和长期命运。特别是，我们测试骨膜是 再生软骨细胞的主要来源，这些软骨细胞直接转化为成骨细胞，产生 编织骨。使用一种新颖的交叉转基因策略来特异性消融再生软骨细胞， 然后我们测试这些细胞是否是斑马鱼颌骨大规模再生所必需的。 在软骨内骨的发育过程中，大多数软骨细胞发生肥大和 细胞凋亡，入侵的成骨细胞产生骨基质。在再生过程中，我们的 初步数据表明，许多软骨细胞直接分化为成骨细胞。使用成人可行的 ihha 突变体和仅在再生软骨细胞中抑制 Hh 信号传导的转基因策略，我们在 第二个目标是持续高 Ihh 信号对于软骨细胞再生分化为至关重要 成骨细胞。这些目标的完成将测试软骨细胞再生能力的模型 直接制造骨骼可以快速恢复受损身体部位的刚性，最初的编织骨骼 后来被重塑为成熟的骨骼。从长远来看，我们计划借鉴这种新斑马鱼的经验教训 模型来设计策略来增强骨骼修复关键尺寸缺陷的固有能力。 ！