PCL聚合物纳米粒子控释HIF-1α诱导OSTERIX修饰的iPS细胞成骨作用及再血管化的研究

It is one of the research hotspots to construct vascularized tissue engineering bone to repair large bone defects in regeneration medicine. Osteoblast-specific transcription factor,Osterix is a transcription factor closely related to craniofacial bone formation,and hypoxia-inducible factors (HIFs) are required for the initiation of the angiogenic-osteogenic cascade. Our previous data demonstrate that,as an upstream regulator of SATB2 during bone formation, Osterix overexpression can lead to SATB2 highly expressed,ex vivo gene therapy of SATB2-modified iPSCs can promote osteogenic differentiation, and SATB2-modified iPSCs combined with silk scaffold can effectively promote bone regeneration in critical-sized calvarial defects.This project is the first to explore the application of Osterix-modified iPS cells,which combined with PCL polymer nanoparticles controlled-released HIF-1α, promote bone regeneration and revascularization.Contents include: Construction of PCL polymer nanoparticles; Observe the biological activity after PCL polymer nanoparticles compounded with HIF-1α; Angiogenesis observation and functional identification of PCL polymer nanoparticle compounded with HIF-1α in vitro and in vivo; Research the regulation mechanism of osteogenesis and angiogenesis promoted by Osterix modified iPS cells and explore the related signal transduction pathways; Observe the effect of rat or minipig cranial or mandibular standard defects repaired with Osterix-modified iPS cells and PCL polymer nanoparticles-HIF-1α scaffold in vitro and in vivo; Explore the possible cell and molecular mechanisms of vascularized tissue engineering bone.This study aimed to explore more effective methods to construct revascularized tissue engineered bone.It is of great scientific importance, and it can provide the theoretical foundations to reconstruct large bone defects in future clinical medicine.

构建血管化组织工程骨修复大块骨缺损是再生医学研究热点之一，Osterix是一个与颅颌面骨形成密切相关的转录因子，在骨形成与血管生成耦合的起始阶段，HIF-1α 是必需的关键因子，我们前期研究显示：Osterix的过表达可致下游靶基因SATB2高表达，将SATB2导入iPS细胞，成骨诱导培养后可促进其成骨分化，与丝素蛋白支架复合在体内可以促进裸鼠颅骨缺损的修复。本课题在前期研究的基础上，通过构建PCL聚合物纳米粒子支架材料持续缓释HIF-1α，分析其血管新生作用，观察Osterix修饰的iPS细胞成骨过程中血管新生情况，进一步研究Osterix与HIF-1α协同作用于iPS细胞，进行成骨诱导分化，检测是否共同促进组织工程化骨形成及再血管化，从而探讨其成骨作用和再血管化的调控机制。本研究旨在提高iPS细胞分化成骨的质和量、为组织工程骨再血管化探索更为有效的方法，因此本课题具有重要的科学意义。

本课题在前期研究的基础上，通过构建PCL 聚合物子支架材料持续缓释HIF-1α，观察Osterix 修饰的iPS 细胞成骨过程中血管新生情况，进一步研究Osterix 与HIF-1α协同作用于iPS 细胞，进行成骨诱导分化的同时促进组织工程化骨形成及再血管化，提高iPS 细胞分化成骨的质和量、为再血管化组织工程骨探索了更为有效的方法，该项目研究成果对将来临床上利用关键性成血管因子HIF-1α 行标准骨缺损修复重建提供了可靠的实验数据，因此本课题具有重要的科学意义。