Srinivasan Akshaya, Teo Nelson, Poon Kei Jun, Tiwari Priya, Ravichandran Akhilandeshwari, Wen Feng, Teoh Swee Hin, Lim Thiam Chye, Toh Yi-Chin
Department of Biomedical Engineering, National University of Singapore, 4 Engineering Drive 3, #04-08, Singapore, 117583.
Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119288.
ACS Biomater Sci Eng. 2021 Jan 11;7(1):207-221. doi: 10.1021/acsbiomaterials.0c00878. Epub 2020 Dec 9.
Most craniofacial bones are derived from the ectodermal germ layer neural crest stem cells, which are distinct from mesoderm-derived long bones. However, current craniofacial bone tissue engineering approaches do not account for this difference and utilize mesoderm-derived bone marrow mesenchymal stem cells (BM-MSCs) as a paradigm cell source. The effect of the embryonic origin (ontogeny) of an MSC population on its osteogenic differentiation potential and regenerative ability still remains unresolved. To clarify the effects of MSC ontogeny on bone regenerative ability, we directly compared the craniofacial bone regenerative abilities of an ecto-mesenchymal stem cell (eMSC) population, which is derived from human embryonic stem cells a neural crest intermediate, with mesodermal adult BM-MSCs. eMSCs showed comparable osteogenic and chondrogenic ability to BM-MSCs in 2-D culture, but lower adipogenic ability. They exhibited greater proliferation than BM-MSCs and comparable construct mineralization in a well-established 3-D polycaprolactone-tricalcium phosphate (PCL-TCP) scaffold system eMSC-derived 3D osteogenic constructs were maintained for longer in a proliferative osteoblast state and exhibited differential levels of genes related to fibroblast growth factor (FGF) signaling compared to BM-MSCs. Although both eMSC and BM-MSC-seeded scaffold constructs could promote bone regeneration in a rat calvarial defect model, eMSC-derived osseous constructs had significantly higher cellularity due to increased number of proliferative (Ki67) cells than those seeded with BM-MSCs, and exhibited enhanced new bone formation in the defect area as compared to untreated controls. Overall, our study demonstrates the potential of human eMSCs for future clinical use in craniofacial regeneration applications and indicates the importance of considering MSC origin when selecting an MSC source for regenerative applications.
大多数颅面骨源自外胚层胚层神经嵴干细胞，这与中胚层衍生的长骨不同。然而，目前的颅面骨组织工程方法并未考虑到这种差异，而是利用中胚层衍生的骨髓间充质干细胞（BM-MSCs）作为典型的细胞来源。间充质干细胞群体的胚胎起源（个体发生）对其成骨分化潜能和再生能力的影响仍未得到解决。为了阐明间充质干细胞个体发生对骨再生能力的影响，我们直接比较了源自人类胚胎干细胞（一种神经嵴中间体）的外间充质干细胞（eMSC）群体与中胚层来源的成人BM-MSCs的颅面骨再生能力。在二维培养中，eMSCs显示出与BM-MSCs相当的成骨和软骨形成能力，但脂肪生成能力较低。在成熟的三维聚己内酯-磷酸三钙（PCL-TCP）支架系统中，它们表现出比BM-MSCs更强的增殖能力和相当的构建体矿化能力——与BM-MSCs相比，eMSC衍生的三维成骨构建体在增殖性成骨细胞状态下维持的时间更长，并且表现出与成纤维细胞生长因子（FGF）信号相关的不同基因水平。尽管接种eMSC和BM-MSC的支架构建体都可以在大鼠颅骨缺损模型中促进骨再生，但eMSC衍生的骨构建体由于增殖（Ki67）细胞数量增加，细胞密度明显高于接种BM-MSCs的构建体，并且与未治疗的对照组相比，在缺损区域表现出增强的新骨形成。总体而言，我们的研究证明了人类eMSCs在未来颅面再生应用临床使用中的潜力，并表明在选择用于再生应用的间充质干细胞来源时考虑间充质干细胞起源的重要性。
