Xu Wan-Lin, Ong Hui-Shan, Zhu Yun, Liu Sheng-Wen, Liu Li-Min, Zhou Kai-Hua, Xu Zeng-Qi, Gao Jun, Zhang Yan, Ye Jin-Hai, Yang Wen-Jun
1 Department of Oral and Maxillofacial-Head and Neck Oncology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University , Shanghai, China .
2 Shanghai Key Laboratory of Stomatology and Shanghai Research Institute of Stomatology , Shanghai, China .
Tissue Eng Part A. 2017 May;23(9-10):445-457. doi: 10.1089/ten.TEA.2016.0315. Epub 2017 Apr 7.
Adipose-derived stem cells (ADSCs) can differentiate into various cell types and thus have great potential for regenerative medicine. Herein, rat ADSCs were isolated; transduced with lentiviruses expressing Osterix (Osx), a transcriptional factor essential for osteogenesis. Osx overexpression upregulated key osteogenesis-related genes, such as special AT-rich binding protein 2, alkaline phosphatase, osteocalcin, and osteopontin, at both mRNA and protein levels. In addition, mineral nodule formation and alkaline phosphatase activity were enhanced in Osx-overexpressing ADSCs. The expression of dickkopf-related protein 1, a potent Wnt signaling pathway inhibitor, was also increased, whereas that of β-catenin, an intracellular signal transducer in the Wnt pathway, was decreased. β-catenin expression was partially recovered by treatment with lithium chloride, a canonical Wnt pathway activator. The Osx-expressing ADSCs were then combined with 3D gelatin-coated porous poly(ɛ-caprolactone) scaffolds with a unique release prolife of entrapped recombinant human vascular endothelial growth factor (VEGF). The controlled release of VEGF promoted osteogenic differentiation capacity in vitro. When the scaffold-ADSC complexes were transplanted into rat calvarial critical-sized defects, more bone formed on the gelatin/VEGF-coated scaffolds than on other scaffold types. Taken together, the results indicate that, Osx-overexpression promotes ADSCs' osteogenesis both in vitro and in vivo, which could be enhanced by release of VEGF.
脂肪来源干细胞（ADSCs）可分化为多种细胞类型，因此在再生医学领域具有巨大潜力。在此，分离出大鼠ADSCs；用表达osterix（Osx）的慢病毒进行转导，Osx是成骨过程中必需的转录因子。Osx过表达在mRNA和蛋白质水平上调了关键的成骨相关基因，如富含AT的特殊结合蛋白2、碱性磷酸酶、骨钙素和骨桥蛋白。此外，过表达Osx的ADSCs中矿化结节形成和碱性磷酸酶活性增强。强效Wnt信号通路抑制剂Dickkopf相关蛋白1的表达也增加，而Wnt通路中的细胞内信号转导子β-连环蛋白的表达则降低。用经典Wnt通路激活剂氯化锂处理可部分恢复β-连环蛋白的表达。然后将表达Osx的ADSCs与3D明胶包被的多孔聚己内酯支架相结合，该支架具有独特的包封重组人血管内皮生长因子（VEGF）释放曲线。VEGF的控释促进了体外成骨分化能力。当将支架-ADSC复合物移植到大鼠颅骨临界尺寸缺损处时，明胶/VEGF包被的支架上形成的骨比其他类型的支架更多。综上所述，结果表明，Osx过表达在体外和体内均促进ADSCs的成骨，VEGF的释放可增强这种作用。
