Mechanisms of apical expansion in calvarial bone morphogenesis

颅骨骨形态发生中根尖扩张的机制

• 批准号: 10056800
• 负责人: RADHIKA P ATIT
• 金额: $ 22.85万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-07 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10056800
• 关键词: 3-Dimensional; Actins; Address; Apical; Behavior; Biophysics; Bone Growth; Brain; Calvaria; Cell Polarity; Cells; Cephalic; Chemotaxis; Congenital Abnormality; Craniofacial Abnormalities; Craniosynostosis; Cues; Data; Defect; Development; Devices; Dysplasia; Embryo; Etiology; Event; Extracellular Matrix; Eye; Fibronectins; Goals; Human; Image; In Vitro; Ligands; Light; Liquid substance; Live Birth; Magnetism; Maps; Mesenchymal; Mesenchyme; Morphogenesis; Movement; Mus; Mutant Strains Mice; Natural regeneration; Organ; Organogenesis; Outcome; Pathway interactions; Pattern; Process; Property; Proteins; Role; Sensory; Signal Pathway; Signal Transduction; Syndrome; Testing; Therapeutic; Tissues; To specify; Variant; WNT Signaling Pathway; base; biophysical techniques; bone; cell behavior; cell motility; cranium; experimental study; in vivo; insight; intercalation; intramembranous bone; live cell imaging; migration; mineralization; mouse genetics; mutant; new therapeutic target; novel; organ growth; planar cell polarity; progenitor; protein expression; skeletal dysplasia; suture fusion

Congenital skull defects such as craniosynostosis and dysplasias occur in 1/2500 live births with detrimental consequences for brain and sensory organ development. We lack basic understanding of how and why the skull bones grow towards the apex, which impacts the direction of intramembranous mineralization and fusion of sutures. The signaling factors and cellular mechanisms underlying the apical expansion of skull bone progenitors remain unidentified. We recently found mouse skull bone progenitors migrate from the supraorbital arch region to the apex and this movement is disrupted in conditional mesenchyme Wntless mutants, that lack all ligand secretion. We also identified a graded expression of fibronectin extracellular matrix in the cranial mesenchyme that is dependent on mesenchyme Wnts, suggesting cell movement by a process of durotaxis in which cells migrate along a stiffness gradient of fibronectin. This proposal intends to define, in vivo, the role of the cranial mesenchyme non-canonical Wnts in directing cellular polarity and durotaxis. In this multi-PI proposal, we will leverage our integrative expertise in conditional mouse genetics, live cell imaging, and emerging biophysical approaches in vivo to address our central hypothesis that mesenchyme Wnts-dependent fibronectin orients the collective movement of calvarial bone progenitors toward the apex by durotaxis. Towards the hypothesis, in Aim1 we will identify the role of mesenchyme Wnts signaling in regulating cell movement behaviors with live light-sheet imaging. In Aim2, we will test if fibronectin directs a tissue-stiffness gradient and collective movement of SOM cells apically by durotaxis. Key deliverables of this R21 proposal include: 1. Developing a framework of cellular behaviors during calvarial bone morphogenesis, 2. the role of SOM-Wnt as a global spatial cue, and 3. the role of durotaxis driven cell movements on a graded fibronectin matrix during calvarial bone growth. Impact: Currently, we lack a conceptual framework for understanding cell movement in calvarial bone expansion, despite its role in highly prevalent craniosynostosis and cranial skeletal dysplasias. The results from these proof-of-concept experiments will serve as a new paradigm in our understanding of cell movement in 3D in mesenchymal cells and provide us fresh insights into skull bone morphogenesis and congenital defects.

先天性头骨缺陷，例如颅突变和发育不良，发生在1/2500 Live中 对大脑和感觉器官发育有害后果的出生。我们缺乏基本 了解颅骨如何以及为什么朝向最高的骨头，这会影响方向 膜内矿化和缝合线的融合。信号因子和细胞 颅骨祖细胞顶端扩张的基础机制仍然不明。 我们最近发现小鼠头骨骨祖细胞迁移从上弓形拱形区域迁移 对顶点和这种运动在条件间充质的无wnt突变体中被破坏， 缺乏所有配体分泌。我们还确定了纤连蛋白外细胞外基质的分级表达 在依赖间充质Wnt的颅间质中，表明细胞运动 通过Durotaxis的过程，细胞沿纤连蛋白的刚度梯度迁移。这 提议打算在体内定义颅间质非典型Wnt的作用 指导细胞极性和杜罗塔克斯。在此多PI提案中，我们将利用我们的综合性 有条件的小鼠遗传学，活细胞成像和新兴生物物理方法的专业知识 在体内解决了我们的中心假设，即间充质Wnts依赖性纤连蛋白 通过 Durotaxis。朝向假设，在AIM1中，我们将确定间充质Wnt的作用 通过实时灯页成像调节细胞运动行为的信号传导。在AIM2中，我们将测试 如果纤连蛋白指导组织 - 静止梯度和SOM细胞的集体运动 Durotaxis。此R21提案的关键可交付成果包括：1。开发蜂窝的框架 钙化骨形态发生过程中的行为，2。som-wnt作为全球空间提示的作用， 和3。在颅骨期间，Durotaxis驱动的细胞运动在分级纤连蛋白基质上的作用 骨生长。 影响：目前，我们缺乏理解钙化细胞运动的概念框架 尽管骨扩展在高度流行的颅突变和颅骨骨骼中的作用 发育不良。这些概念验证实验的结果将作为新的范式 在我们对间充质细胞中3D细胞运动的理解中，并为我们提供新的见解 进入颅骨形态发生和先天性缺陷。