mTORC1信号通路参与先天性脊柱侧凸发育畸形中的作用及其机制研究

The main cause of congenital scoliosis(CS) is the abnormal development of vertebral. The formation of vertebral bone is primarily the process of endochondral bone formation.The onset of CS is closed related to the changes of mesenchymal stem cells(BMSCs),however the underlying pathogenesis of CS is still unclear,which leads to lack of effective prevention and therapy. Mammalian target of rapamycin complex 1(mTORC1) serves as a central regulator of cell metabolism,growth,proliferation and survival.Our preliminary study suggested that specific knock-out TSC1 in mesenchymal stem cells during the skeletal development,which up-regulates the mTORC1 signalling,could result in the obvious kyphosis、spinal dysplasia and deformity of spine.These results indicate that mTORC signalling pathway could play an important role in the development of spine.We intend to dually modulate the mTORC1 signalling in BMSCs-specific knock-out mice(knock out TSC1 or Raptor) before and after the CS model established、and the various stages of its growing development.Our proposal aims to study the relationship between mTORC1 signalling activity of BMSCs and CS,and investigate the mechanis,which will be beneficial for the further CS treatment targeting for the mTORC1 signalling of mesenchymal stem cells.

先天性脊柱侧凸（CS）是椎体发育异常所致。胚胎时期间充质干细胞（MSCs）影响脊柱发育，但其原因与分子机制有待阐明。雷帕霉素靶蛋白复合物1(mTORC1)是感受营养与应激信号调节细胞生长与代谢的中心调控分子。课题组前期发现在骨髓间充质干细胞中敲除TSC1活化mTORC1信号出现明显的椎体发育异常并后凸畸形、侧凸畸形等，提示mTORC1活化在脊柱发育过程中起重要作用。本课题拟构建可诱导、间充质干细胞特异TSC1敲除小鼠模型，在其生长发育不同阶段以及脊柱畸形造模前后的不同时间，分别使其间充质干细胞mTORC1激活和失活，观察其椎体发育情况，从分子、细胞与整体水平阐明间充质干细胞mTORC1在椎体发育与CS发病中的作用并探讨其分子机理，为CS发病机制与mTORC1功能增加新内容及防治提供新靶点。

先天性脊柱畸形是世界范围内最严重的骨科临床问题。对于自发性胸部发育不良和呼吸器官功能丧失，先天性脊柱脱位被认为是一种致命疾病，死亡率大于60%。然而，由于涉及的分子机制，先天性脊柱畸形的病理过程尚不完全清楚。软骨内骨化是从软骨中间物开始的骨形成过程，对骨骼发育至关重要。最近的研究表明，雷帕霉素（mTOR）对关节生长和骨骼发育具有重要作用。mTOR和mTORC1复合物1（mTORC1）基因敲除（KO）小鼠表现出延迟的胚胎骨生长和软骨肥大，从而最终阻止骨形成。在先天性脊柱畸形的所有病理过程中，软骨内骨化的不平衡被认为是脊柱发育不良最重要的发展原因。我们建立了软骨细胞特异性TSC-1基因敲除（KO）小鼠，以过度激活能量代谢成分，即雷帕霉素复合物1（mTORC1）的哺乳动物靶点，并通过常规、影像学、组织学和Western blot评估来测量脊柱发育。除了骨骼发育不良外，KO小鼠还表现出严重的先天性脊柱畸形和显著的椎间盘改变。本研究表明，在软骨内骨化过程中，软骨细胞中mTORC1信号过度激活会导致明显的脊柱畸形，软骨细胞可能是导致先天性脊柱畸形的细胞类型。