CCN2/BMP2在下颌骨骨折愈合过程中的交互作用及分子信号转导机制

Both CCN2 and BMP2 can be detected during fracture healing, and they promote proliferation and differentiation of osteoblasts. Compared with application of CCN2 or BMP2 alone, combined application of CCN2 and BMP2 inhibits proliferation and promote differentiation. CCN2 interacts with BMP2 to form a heterooligomer might regulate this process. However, effects and molecular mechanisms of protein-protein interaction between CCN2 and BMP2 during mandibular fracture healing remain unclear. According to establish the animal model of mandibular fracture, we would detect spatiotemporal expression of CCN2/BMP2, to analyze the relationship between fracture healing. We would culture chondrocytes and osteoblasts, intervene with different ratio of CCN2 to BMP2, or transfect with Lenti-CCN2 or Lenti-BMP2 RNAi, to detect the effects on phenotype, proliferation, differentiation, and mineralization and analyze possible molecular mechanisms. In addition, we would intervene animal models with the intervention mentiaoned above, to detect the changes of fracture healing, osteoblast function, and osteoclast function, to analyze effects of protein-protein interaction between CCN2 and BMP2 on mandibular fracture healing and influences of different ration of CCN2 to BMP2 or sequential dose of CCN2/BMP2 on mandibular fracture healing. This project is aimed to clarify the mechanism of protein-protein interaction between CCN2 and BMP2 during fracture healing.

CCN2及BMP2均可促进细胞增殖和分化，并在骨折愈合过程中表达。与CCN2或BMP2单独应用相比，CCN2/BMP2联合应用对细胞的作用明显不同。该过程中CCN2与BMP2结合形成聚合物可能发挥重要作用，但CCN2/BMP2在骨折愈合过程中的交互作用及调控机制目前仍不清楚。本项目通过建立下颌骨骨折动物模型，检测骨折愈合过程中CCN2/BMP2的时空表达，分析CCN2/BMP2表达与骨折愈合的量效关系；通过培养软骨细胞和成骨细胞，检测细胞分化各阶段CCN2与BMP2的交互作用；分别给予不同配比的CCN2/BMP2及转染慢病毒介导的RNAi CCN2或BMP2等，检测刺激因素对细胞表型、增殖、分化、矿化和功能的影响；利用骨折动物模型，同上给予刺激，检测刺激因素对骨折愈合、成骨功能、破骨功能的影响。通过本项目研究，阐明CCN2/BMP2在下颌骨骨折愈合过程中的交互作用及分子信号转导机制。

本项目针对口腔颌面组织创伤修复领域存在的一些关键问题，主要在颌面部骨折、骨缺损愈合模型建立和CCN2在骨折愈合过程中的作用及调控机制两方面开展创新性研究工作。根据原项目计划研究内容，同时结合当前国际上该领域的最新进展和存在的问题，项目组通过4年的努力，成功研制出一种新型小鼠坚固内固定装置，建立兔下颌骨骨折实验动物模型。对CCN2 在骨折愈合过程中的调控作用过行了系列研究，发现CCN2对骨愈合过程中成骨细胞的骨向分化起着关键调节作用，转染其基因后的细胞可以在体内外显著提高骨形成。同时发现溶血磷脂酸通过G蛋白偶联受体/ PKA和PKC通路对成骨细胞分泌的CCN2进行调节，探索了调控CCN2表达的分子作用机制。