PTH和SDF-1介导的双向干细胞效应对牙周组织再生的影响

Stem cell transplantation-based traditional periodontal tissue engineering is one important direction of regeneration and reconstruction of periodontal defect. However, many barriers limit its clinical application. Therefore, mobilization and recruitment of enough functional cells to the defect area to reestablish the destroyed periodontium becomes a new strategy for periodontal regeneration, which is hoped to be realized by the dual effects of pushing and pulling on stem cells mediated by the combination of PTH and SDF-1. Systemic application of PTH can mobilize stem cells from bone marrow into circulation and prevent the proteolytic cleavage of SDF-1 by inhibiting the specific protease DPP-IV. Meanwhile, local administration of SDF-1 can facilitate the chemotaxis and migration of stem cells to the site of injury. Based on our previous studies that SDF-1 could recruit and home stem cells and significantly promote periodontal regeneration, we propose to investigate the effects of PTH and SDF-1 combination on the proliferation, chemotaxis, differentiation of periodontal ligament stem cells, as well as the influence on DPP-IV activity and CXCR4 expression in vitro. Moreover, rat periodontal defects will be created to explore the effects of PTH and SDF-1 combination on the number of stem cells, DPP-IV activity and CXCR4 expression in blood circulation and periodontal wound, and periodontal regeneration in vivo. This study will evaluate the synergic effects and mechanism of the combination of PTH and SDF-1 on stem cells mobilization and recruitment, as well as periodontal regeneration. This strategy will help to create new insight for the clinical therapy of periodontal diseases and provide scientific foundation for the successful application of in situ tissue engineering technique in periodontal tissue regeneration.

基于干细胞移植的牙周组织工程是修复牙周缺损的重要方向，但要转化为临床应用存在很多障碍。因此，动员募集足量自身功能细胞迁移到创区，重建牙周组织成为牙周再生的新策略。该策略有望通过PTH和SDF-1联合应用介导的对干细胞的推和拉双向效应来实现，即通过全身应用PTH动员骨髓基质细胞进入血液，并抑制DPP-IV对SDF-1的降解，同时局部应用SDF-1以趋化募集干细胞归巢至创区。本项目基于前期SDF-1能够趋化干细胞并显著促进牙周再生的基础上，拟通过体外实验探讨PTH和SDF-1联合对牙周膜干细胞增殖、趋化、分化等效应及对DPP-IV活性、SDF-1受体CXCR4表达的影响；通过体内实验探讨两者联合对外周血和缺损区干细胞数量、DPP-IV活性、CXCR4表达及牙周再生的影响，从而评价两者联合应用对干细胞动员募集及牙周再生的总效应及作用机制。这一策略有望为原位组织工程技术应用于牙周再生提供科学依据。

诱导因子和支架材料在重建和再生颌面部组织缺损中具有重要意义。该项目以此作为切入点，在优化组织工程、促进牙周再生及组织缺损修复方面做出贡献。在ACS Appl Mater Interfaces, Nanomedicine, Mater Sci Eng C, Cell Prolif等SCI收录杂志上发表论文15篇，均标明NSFC资助号81371157。申请国家发明专利“PTH联合SDF-1在制备促进牙周组织再生的药物中的应用”，在实质审查阶段。在该项目的资助下，培养了多名优秀研究生和本科生。项目组成员多次参加国内外组织再生及牙周病学术会议汇报成果，获得同行专家一致认可，主要内容如下：.（1）引入原位组织工程概念，优化诱导因子，改善干细胞性能，促进组织再生。利用SDF-1对干细胞的募集归巢作用及PTH对干细胞的动员效应，二者联合发挥对干细胞的推和拉的双向促进效应，募集干细胞迁移至牙周缺损区，并促进MSCs增殖、迁移和成骨分化。在创区联合应用时，启动宿主修复潜能，动员自身干细胞到达创区，促进早期破骨细胞活跃，调节骨的平衡和稳态，还能促进成骨相关蛋白表达，提高新生骨质量，同时改善新生牙周膜纤维的质量，并促进新生牙骨质形成。通过PTH和SDF-1的联合应用能协同促进愈合过程中牙周/骨组织再生，为原位牙周组织工程策略进一步临床转化奠定了坚实的基础。.（2）研究了GO、TNRs纳米材料作为植骨和植体表面修饰的可行性。检测其理化特性及生物相容性并通过体外实验检测对牙源性干细胞增殖、迁移及成骨分化等生物学活性的影响；检测其对牙周可疑致病菌及真菌的抑菌效应及作用机制。.（3）研究了牙周炎发生、发展的机制，从微生态角度探讨治疗策略，并探讨了经典降糖老药的抗炎机制。研究了LPS及幽门螺旋杆菌在牙周炎发病中的作用机制，用宏基因组的方法探讨了牙周炎治疗前后菌群组成的变化，并研究了二甲双胍用于治疗糖尿病牙周炎的可能机制。.总之，该项目为牙周病、组织创伤探讨了新的治疗策略，支架材料和诱导因子，促进了原位牙周组织工程技术在牙周再生治疗中的应用和发展，为临床牙周病及口腔颌面部缺损的治疗奠定理论依据和实验基础。