X基因突变调控间充质干细胞异常分化在青少年特发性脊柱侧凸发病中的作用机制研究

Adolescent idiopathic scoliosis (AIS) is the most common pediatric spinal deformity, the etiology and pathogenesis of which remains unknown. Heritable factors play a vital role in the occurrence and development of AIS. We have collected several AIS families and mapped the location of functional X gene mutation (unpublished), but how gene mutation lead to AIS skeletal dysplasia is largely unknown. Spine developed by osteogenic and chondrogenic differentiation of mesenchymal stem cells (MSCs). Therefore, we suspect that the skeletal system deformities of AIS patients might due to abnormal differentiation ability of MSCs carrying mutant gene.Our pre-experiments suggested osteogenic and chondrogenic ability of MSCs carrying mutant X gene decreased obviously than that of MSCs with wild-type X gene. In this work, spinal deformity law of AIS patients will be studied by imageological examination.The differentiation model of MSCs will be performed to explore the effect of the X gene mutation on osteogenic and chondrogenic differentiation of MSCs. The mechanism of signal transduction will be further studied to clarify gene function and the pathogenesis of AIS.

青少年特发性脊柱侧凸（Adolescent idiopathic scoliosis, AIS）是青少年最常见的脊柱畸形，发病机制仍不明确，遗传因素在AIS的发生中起重要作用。我们前期收集了多个AIS家系，已定位出致病基因为X基因上的点突变（未发表）。然而X基因突变如何导致AIS脊柱骨骼畸形发育的具体机制仍未可知。脊柱骨的发育源于间充质干细胞（Mesenchym stem cells，MSCs）向骨、软骨的分化。因此，我们提出AIS患者骨骼畸形发育可能是X基因突变导致干细胞向骨、软骨分化异常所致。预实验提示高表达X突变基因的MSCs成骨、成软骨能力下降。本项目拟进一步通过影像学研究AIS患者脊椎畸形规律，采用X基因RNA干扰及过表达MSCs分化模型，研究突变基因对MSCs成骨、成软骨分化的影响以及具体的信号转导机制，探讨AIS骨骼畸形与X基因功能关系，阐明AIS的发病机制。

青少年特发性脊柱侧凸(adolescent idiopathic scoliosis, AIS)是青少年最常见的脊柱畸形，发病率约为2-3%。目前由于该病的病因、发病机制仍不明确，严重制约了疾病的临床诊疗。目前认为遗传因素在AIS的发生中起重要作用。本项目通过收集的一个中国汉族三代AIS家系以及其他几个AIS家系，利用全外显子测序和links分析，首次鉴定了MAPK7的三个错意突变(c.886G> A, c.1943C> T, and c.1760C> T涉及AIS的致病,并进行了人群及斑马鱼脊柱侧弯模型验证。我们通过构建MAPK7过表达突变型及野生型慢病毒载体转染人的骨髓间充质干细胞，构建AIS干细胞的分化模型，从脊柱骨生长发育的起始点——干细胞分化阶段，证明MAPK7点突变导致干细胞的成骨、成软骨分化障碍，并且明显减弱了MAPK7的入核能力及与下游信号蛋白RSK2,MEF2C结合能力，过表达rps6ka3b（RSK2编码基因） mRNA能纠正mapk7突变导致的斑马鱼体轴弯曲，阐明了MAPK7点突变通过影响MAPK7信号通路的活性导致成骨、成软骨能力下降，可能是导致AIS发生的重要机制。本项目的实施对于明确AIS致病机制，从而推动临床AIS特异性诊疗技术的发展具有重要的科学意义。