Trio调控神经嵴细胞迁徙进而影响颌面部发育的机制研究

Most of maxillofacial hard tissues are derived from neural crest cells (NCC), including bones, cartilages and teeth. Trio, which is one of the members of Rho GTPase family, is involved in the regulation of the migration of neural crest cells. However, the roles and mechanisms of Trio in the development of maxillofacial tissues remain to be elucidated further. Recently We found that Trio was highly expressed in the neural crest migration stage of the fetal mice maxillofacial tissues than that of the late stage. Moreover, our preliminary data showed that c.3239 A>T mutation of Trio gene was closely correlated with human mandibular prognathism, and some obvious maxillofacial deformities and retard of palatine process fusion were observed in the NCC conditional knockout of Trio gene mice. Therefore, we proposed the hypothesis that Trio is involved in the maxillofacial development via regulating the migration of NCC and the abnormal expression of Trio gene may lead to maxillofacial deformities. To determine the important roles of Trio in the maxillofacial development, we will perform SNP analysis of Trio gene using the blood samples of patients with mandibular prognathism, do the phenotype analysis of the NCC conditional knockout mice of Trio gene. In addition, technologies of cell biology and molecular biology will be used to explore the mechanisms by which Trio regulates the migration of NCC. Results of this project will not only be helpful for the elucidation of the molecular mechanisms of maxillofacial development, but also provide a theoretical and experimental basis for the prevention and treatment of maxillofacial deformities such as mandibular prognathism and cleft palate.

颌面部的大部分骨、软骨及牙齿等硬组织由神经嵴细胞衍生形成。Trio基因是Rho GTP酶家族成员，参与神经嵴细胞迁徙的调控，但Trio在颌面发育中的作用及其机制尚有待进一步阐明。本课题组前期发现Trio在神经嵴迁徙期的胎鼠颌面组织中显著高表达。我们研究结果还表明：该基因c.3239 A>T突变与人下颌前突畸形密切相关；Trio神经嵴细胞特异敲除小鼠的的颌面呈明显畸形，且腭突融合迟缓。由此我们推测：Trio通过调控神经嵴细胞的迁徙而参与颌面部发育；Trio基因的表达异常可导致颌面部畸形。本项目拟通过人血样SNP分析，Trio神经嵴细胞特异性敲除小鼠的构建及表型分析，并结合细胞生物学和分子生物学等技术确定Trio在颌面发育中的重要作用，深入探讨其调控神经嵴细胞迁徙的分子机制。本课题的实施，有望进一步阐明颌面发育的的分子机理，从而为下颌前突、腭裂等畸形的防治提供新的理论和实验基础。

神经嵴细胞是颅面发育的主要来源细胞之一，具有独特的迁移和分化能力，其异常迁移和分化可导致包括颅面畸形在内的多种疾病。前期研究显示人Trio突变可导致颅面发育缺陷、下颌后缩，表明Trio可能通过调控神经嵴细胞的功能而影响颅面发育。本课题组拟进一步通过斑马鱼和小鼠两种模式动物，探究敲除Trio基因对神经嵴细胞增殖、凋亡、迁移、分化的影响，以及在体外神经嵴细胞中敲低Trio对细胞迁移、增殖、凋亡、成骨能力的影响，并结合iTRAQ差异蛋白质组学研究筛选其协同作用基因，以阐明Trio调控神经嵴细胞的作用机制。研究结果讲有助于了解Trio对颅面发育的影响及作用机制，有望为颅面畸形症的预防和治疗提供新的靶点。