Department of Orthopaedic Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China; Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15217, USA.
Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15217, USA; Xiangya Third Hospital, Central South University, Changsha, Hunan, 410008, China.
Biomaterials. 2019 Oct;218:119336. doi: 10.1016/j.biomaterials.2019.119336. Epub 2019 Jul 6.
Mesenchymal stem cells (MSCs) embedded in their secreted extracellular matrix (mECM) constitute an exogenous scaffold-free construct capable of generating different types of tissues. Whether MSC-mECM constructs can recapitulate endochondral ossification (ECO), a developmental process during in vivo skeletogenesis, remains unknown. In this study, MSC-mECM constructs are shown to result in robust bone formation both in vitro and in vivo through the process of endochondral ossification when sequentially exposed to chondrogenic and osteogenic cues. Of interest, a novel trypsin pre-treatment was introduced to change cell morphology, which allowed MSC-mECM constructs to undergo the N-cadherin-mediated developmental condensation process and subsequent chondrogenesis. Furthermore, bone formation by MSC-mECM constructs were significantly enhanced by the ECO protocol, as compared to conventional in vitro culture in osteogenic medium alone. This was designed to promote direct bone formation as seen in intramembranous ossification (IMO). The developmentally informed method reported in this study represents a robust and efficacious approach for stem-cell based bone generation, which is superior to the conventional osteogenic induction procedure.
间质干细胞（MSCs）嵌入其分泌的细胞外基质（mECM）中，构成一种能够生成不同类型组织的外源性无支架构建体。MSC-mECM 构建体是否能够重现软骨内骨化（ECO），即在体内骨发生过程中的一种发育过程，目前尚不清楚。在这项研究中，通过将 MSC-mECM 构建体依次暴露于软骨形成和成骨信号中，通过软骨内骨化的过程，显示其在体外和体内均能产生强大的骨形成。有趣的是，引入了一种新的胰蛋白酶预处理方法来改变细胞形态，这使得 MSC-mECM 构建体能够经历 N-钙黏蛋白介导的发育凝聚过程和随后的软骨形成。此外，与单独在成骨培养基中进行传统的体外培养相比，ECO 方案显著增强了 MSC-mECM 构建体的成骨作用。这旨在促进类似于膜内成骨（IMO）的直接骨形成。本研究报告的这种具有发育信息的方法代表了一种基于干细胞的骨生成的强大和有效的方法，优于传统的成骨诱导程序。
