The origin and function of tendon progenitors in craniofacial morphogenesis and patterning

 描述(申请人提供)：颅面肌肉骨骼系统的发育是一个复杂的过程，涉及细胞类型指定、形态发生、图案化和生长的协调。许多人类头面部疾病，如先天性畸形或出生后疾病，往往是由于这些过程中的一个或多个被破坏所致。尽管对颅面疾病的遗传基础有了很大的了解，但对颅面发育的许多方面仍然知之甚少。特别是，结缔组织细胞的类型，肌腱和韧带，如何在颅面部肌肉骨骼的发育和生长中指定和发挥作用尚不清楚。事实上，肌肉骨骼组织的精确放置和协调组装是正确运动所必需的。在颅骨内，肌肉骨骼系统的异常组装或生长可导致头面部畸形或疾病。肌腱和韧带是肌肉骨骼系统的重要组成部分，起着连接肌肉和骨组织的作用。令人惊讶的是，考虑到它们在运动中的重要性，人们对它们的形成和调节肌肉骨骼模式和生长的功能知之甚少。移植研究表明，神经脊来源的结缔组织形成了肌肉附着部位的模式，但颅腱和韧带前体在这一过程中或在调节颅面发育其他事件中的具体功能尚未被探索。我们的目标是使用斑马鱼模型系统来解决这些主要问题。在斑马鱼中，我们已经证实，头面部的肌腱和韧带在基因表达、形态、发育规律和超微结构特征上与哺乳动物的肌腱相似。使用我们的肌腱和韧带标记以及一个可光转换的转基因株系，我们将创建早期咽弓区域内肌腱和韧带祖细胞的精确命运图。这些谱系实验将为未来专注于肌腱细胞在不同功能环境中的指定和分化的研究奠定基础。接下来，我们设计了转基因细胞系来进行肌腱和韧带细胞消融实验，从而确定它们在颅面发育和生长中的旁分泌作用。最后，我们创建了SCX突变斑马鱼品系，以研究其在肌腱伸长和头面部肌肉骨骼形态发生中的作用。总之，这些实验为阐明在颅面肌肉骨骼发育背景下调节肌腱和韧带细胞诱导和功能的分子通路提供了不可或缺的一步，并有可能影响我们对颅面疾病的理解。

 DESCRIPTION (provided by applicant): The development of the craniofacial musculoskeletal system is a complex process involving the coordination of cell type specification, morphogenesis, patterning and growth. Many human craniofacial conditions such as congenital malformations or postnatal disorders often result from disruptions to one or many of these processes. Despite advances understanding the genetic basis of craniofacial diseases, many aspects of craniofacial development remain poorly understood. In particular, it is unknown how the connective tissue cell types, the tendons and ligaments, are specified and function in craniofacial musculoskeletal development and growth. Indeed, the precise placement and coordinated assembly of the musculoskeletal tissues is required for proper movement. Within the cranial skeleton, abnormal assembly or growth of the musculoskeletal system can result in craniofacial dysmorphology or disease. Tendons and ligaments are essential components of the musculoskeletal system by serving to connect the muscle and bone tissues. Surprisingly, given their importance in enabling movement, very little is known about their formation and function in regulating musculoskeletal patterning and growth. Transplantation studies have suggested that the neural crest derived connective tissues pattern the muscle attachment sites, but the specific function of the cranial tendon and ligament progenitors in this process or in the regulation of other events in craniofacial development has not been explored. We aim to address these major questions using the zebrafish model system. In the zebrafish, we have established that the tendons and ligaments in the craniofacial region are analogous to mammalian tendons in gene expression, morphology, developmental regulation, and ultrastructural characteristics. Using our tendon and ligament markers and a photoconvertible transgenic line, we will create a precise fate map of the tendon and ligament progenitors within the early pharyngeal arch domains. These lineage experiments will be the basis for future studies focusing on tendon cell specification and differentiation in different functional contexts. Next, we have engineered transgenic lines to perform tendon and ligament cell ablation experiments, thus determining their paracrine role in craniofacial development and growth. Finally, we have created scx mutant zebrafish lines to study its role in tendon elongation and craniofacial musculoskeletal morphogenesis. Together, these experiments provide an integral step towards elucidating the molecular pathways regulating tendon and ligament cell induction and function in the context of craniofacial musculoskeletal development, and have the potential to impact our understanding of craniofacial disorders.