Molecular and Cellular Basis of Craniosynostosis

颅缝早闭的分子和细胞基础

基本信息

批准号：
10365746
负责人：
Gage D Crump
金额：
$ 61.88万
依托单位：
UNIVERSITY OF SOUTHERN CALIFORNIA
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-07-01 至 2026-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10365746
关键词：
Address Affect Alleles Animal Model Biology Bone Growth Brain Cells Chotzen Syndrome Clustered Regularly Interspaced Short Palindromic Repeats Complex Congenital Abnormality Congenital abnormal Synostosis Craniosynostosis DNA Sequence Alteration Data Defect Development Embryo Etiology Excision Family Fetal Development Fishes Functional disorder Funding Genes Genetic Genomics Goals Growth Human Human Genetics Image Impaired cognition Individual Infant Intellectual functioning disability Joint structure of suture of skull Joints Left Light Link Live Birth Measurement Modeling Molecular Monitor Mus Mutagenesis Mutation Operative Surgical Procedures Orthologous Gene Osteoblasts Osteogenesis Patients Phenocopy Postoperative Period Process Regulation Repeat Surgery Reporter Role Signal Transduction Source Structure Surgical sutures TWIST1 gene Testing Transgenic Organisms Up-Regulation Validation Work Zebrafish base blastomere structure bone cell type comparative coronal suture coronal synostosis craniofacial cranium early childhood flexibility in vivo molecular marker mouse model mutant postnatal premature preservation prevent progenitor programs quantitative imaging single-cell RNA sequencing stem cells suture fusion targeted treatment therapy development tool transcription factor transcriptome

项目摘要

During fetal development and early childhood, growth of the bony skull accommodates a rapid expansion of the underlying brain. This is accomplished first by progenitors that grow the individual skull bones, and then by stem cells residing in the flexible bony joints called sutures. In a common birth defect called craniosynostosis (1 in 2000 live births), loss of the cranial sutures results in bony fusions that impede brain growth, thus leading to cognitive impairment if left untreated. Surgical correction involves invasive and risky surgeries on infants to break apart the fused bones. Unfortunately, the skull bones often re-fuse, necessitating repeated surgeries. There is thus a critical need to better understand the causes of craniosynostosis, such that we can develop therapies that minimize repeated surgical interventions. In the previous funding cycle, we generated and characterized the first zebrafish model of Saethre-Chotzen Syndrome, which preferentially affects the coronal suture. In so doing, we pinpointed early changes in the growth rates of the embryonic skull bones as a major cause of suture fusions. In this renewal we address three outstanding questions in the field of craniosynostosis. In Aim 1, we investigate the embryonic origins of the suture stem cells that grow and maintain the skull. While suture stem cells have been studied at postnatal stages, whether they arise from progenitors at the tips of growing bones, or alternatively from migrating cells, remains debated. By generating the first single-cell transcriptomes of the developing mouse and zebrafish coronal sutures, we have uncovered conserved embryonic cell types and molecular markers for suture progenitors. Using new lineage tracing tools in mouse and fish, we will test that bone front progenitors expressing ETS-family transcription factors are the origin of suture-resident stem cells. In Aim 2, we investigate how the Saethre-Chotzen genes Twist1 and Tcf12 regulate the transition from bone front progenitors to suture stem cells. Preliminary data reveal that Twist1 and Tcf12 upregulate the Bmp antagonists Grem1 and Noggin during suture formation, suggesting that tighter regulation of Bmp signaling is essential to slow bone growth and prevent fusions. Using mouse conditional genetics and new zebrafish mutants, we will test that direct regulation of Grem1 and Noggin expression by Twist1 and Tcf12 is necessary and sufficient for regulated bone growth and normal suture formation. In Aim 3, we address a central mystery of the craniosynostosis field – why do particular mutations tend to affect only particular sutures? By generating and contrasting new zebrafish models for 11 coronal and 7 midline craniosynostosis genes, we will test whether coronal suture formation is particularly sensitive to mutations that perturb the rate of bone growth. To do so, we will make use of new zebrafish transgenic reporters that allow quantitative in vivo measurements of osteoblast addition and suture formation. A strength of the proposal is the unique team of experts in zebrafish, mouse, and human craniofacial genetics. By using model organisms to understand the developmental bases for diverse types of craniosynostosis, we strive toward developing more targeted treatments for craniosynostosis patients with particular genetic mutations.

在胎儿发育和幼儿期，颅骨的生长适应了颅骨的快速扩张。这首先是由生长单个颅骨的祖细胞完成的，然后是由干细胞完成的。存在于称为缝线的灵活骨关节中的细胞存在于一种称为颅缝早闭的常见出生缺陷中。 2000 活产），颅缝丢失导致骨融合，阻碍大脑生长，从而导致如果不及时治疗，认知障碍会涉及对婴儿进行侵入性且危险的手术。不幸的是，头骨经常会重新融合，需要重复手术。因此，迫切需要更好地了解颅缝早闭的原因，以便我们能够开发出治疗方法在上一个资助周期中，我们生成并描述了第一个手术干预措施。 Saethre-Chotzen 综合征的斑马鱼模型，它优先影响冠状缝。确定胚胎颅骨生长速度的早期变化是缝线融合的主要原因。此次更新我们解决了颅缝早闭领域的三个突出问题。在目标 1 中，我们进行了调查。生长和维持颅骨的缝合干细胞的胚胎起源，而缝合干细胞具有在出生后阶段进行了研究，无论它们是否来自生长骨骼尖端的祖细胞，或者通过生成发育中的小鼠的第一个单细胞转录组，仍然存在争议。和斑马鱼冠状缝，我们发现了保守的胚胎细胞类型和分子标记使用小鼠和鱼的新谱系追踪工具，我们将测试骨前祖细胞。表达 ETS 家族转录因子是缝线驻留干细胞的起源。在目标 2 中，我们进行了研究。 Saethre-Chotzen 基因 Twist1 和 Tcf12 如何调节从骨前祖细胞到缝合线的转变初步数据显示，Twist1 和 Tcf12 上调 Bmp 拮抗剂 Grem1 和 Noggin。在缝合线形成过程中，表明更严格地调节 Bmp 信号对于减缓骨生长和使用小鼠条件遗传学和新的斑马鱼突变体，我们将测试直接调节 Twist1 和 Tcf12 的 Grem1 和 Noggin 表达对于调节骨生长和在目标 3 中，我们解决了颅缝早闭领域的一个核心谜团——为什么会出现特殊的情况。通过生成并对比 11 种新的斑马鱼模型，突变是否倾向于只影响特定的缝合线？冠状和7个中线颅缝早闭基因，我们将测试冠状缝的形成是否特别对扰乱骨骼生长速度的突变敏感为此，我们将利用新的斑马鱼。转基因生产可以定量体内测量成骨细胞的添加和缝合线的形成。该提案的优势在于由斑马鱼、小鼠和人类颅面遗传学专家组成的独特团队。使用模型生物体来了解不同类型颅缝早闭的发育基础，我们努力致力于为具有特定基因突变的颅缝早闭患者开发更有针对性的治疗方法。