Department of Oral & Cranio-Maxillofacial Surgery, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, 200011, PR China.
Department of Oral & Cranio-Maxillofacial Surgery, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, 200011, PR China.
Biomaterials. 2021 May;272:120718. doi: 10.1016/j.biomaterials.2021.120718. Epub 2021 Mar 27.
Mesenchymal stem cell-derived exosomes (MSC-exos), with its inherent capacity to modulate cellular behavior, are emerging as a novel cell-free therapy for bone regeneration. Herein, focusing on practical applying problems, the osteoinductivity of MSC-exos produced by different stem cell sources (rBMSCs/rASCs) and culture conditions (osteoinductive/common) were systematically compared to screen out an optimized osteogenic exosome (BMSC-OI-exo). Via bioinformatic analyses by miRNA microarray and in vitro pathway verification by gene silencing and miRNA transfection, we first revealed that the osteoinductivity of BMSC-OI-exo was attributed to multi-component exosomal miRNAs (let-7a-5p, let-7c-5p, miR-328a-5p and miR-31a-5p). These miRNAs targeted Acvr2b/Acvr1 and regulated the competitive balance of Bmpr2/Acvr2b toward Bmpr-elicited Smad1/5/9 phosphorylation. On these bases, lyophilized delivery of BMSC-OI-exo on hierarchical mesoporous bioactive glass (MBG) scaffold was developed to realize bioactivity maintenance and sustained release by entrapment in the surface microporosity of the scaffold. In a rat cranial defect model, the loading of BMSC-OI-exo efficiently enhanced the bone forming capacity of the scaffold and induced rapid initiation of bone regeneration. This paper could provide empirical bases of MSC-exo-based therapy for bone regeneration and theoretical bases of MSC-exo-induced osteogenesis mechanism. The BMSC-OI-exo-loaded MBG scaffold developed here represented a promising bone repairing strategy for future clinical application.
间充质干细胞衍生的外泌体（MSC-exos）具有调节细胞行为的固有能力，正在成为一种新的无细胞治疗骨再生的方法。在此，我们聚焦于实际应用问题，系统比较了不同干细胞来源（rBMSCs/rASCs）和培养条件（成骨诱导/常规）产生的 MSC-exos 的成骨能力，以筛选出一种优化的成骨外泌体（BMSC-OI-exo）。通过 miRNA 微阵列的生物信息学分析和基因沉默及 miRNA 转染的体外通路验证，我们首先揭示了 BMSC-OI-exo 的成骨能力归因于多种成分的外泌体 miRNA（let-7a-5p、let-7c-5p、miR-328a-5p 和 miR-31a-5p）。这些 miRNA 靶向 Acvr2b/Acvr1，并调节 Bmpr 诱导的 Smad1/5/9 磷酸化中 Bmpr2/Acvr2b 的竞争平衡。在此基础上，我们通过冷冻干燥将 BMSC-OI-exo 负载到分级介孔生物活性玻璃（MBG）支架上，通过支架表面微孔的包埋实现了生物活性的维持和持续释放。在大鼠颅缺损模型中，BMSC-OI-exo 的负载有效增强了支架的成骨能力，并诱导了快速的骨再生起始。本文为基于 MSC-exo 的骨再生治疗提供了经验基础，为 MSC-exo 诱导成骨机制提供了理论基础。这里开发的负载 BMSC-OI-exo 的 MBG 支架为未来的临床应用提供了一种有前途的骨修复策略。
