Antebi Ben, Zhang ZhiLiang, Wang Yu, Lu ZhongDing, Chen Xiao-Dong, Ling Jian
1 Microencapsulation and Nanomaterials Department, Southwest Research Institute , San Antonio, Texas.
Tissue Eng Part C Methods. 2015 Feb;21(2):171-81. doi: 10.1089/ten.TEC.2014.0092. Epub 2014 Aug 4.
To date, expansion of bone-marrow-derived mesenchymal stem cells (MSCs) is typically carried out on two-dimensional (2D) tissue culture plastic. Since this 2D substratum is very different from the physiological situation, MSCs gradually lose their unique multipotent properties during expansion. Recently, the role of the extracellular matrix (ECM) microenvironment ("niche") in facilitating and regulating stem cell behavior in vivo has been elucidated. As a result, investigators have shifted their efforts toward developing three-dimensional (3D) scaffolds capable of functioning like the native tissue ECM. In this study, we demonstrated that stromal-cell-derived ECM, formed within a collagen/hydroxyapatite (Col/HA) scaffold to mimic the bone marrow "niche," promoted MSC proliferation and preserved their differentiation capacity. The ECM was synthesized by MSCs to reconstitute the tissue-specific 3D microenvironment in vitro. Following deposition of the ECM inside Col/HA scaffold, the construct was decellularized and reseeded with MSCs to study their behavior. The data showed that MSCs cultured on the ECM-Col/HA scaffolds grew significantly faster than the cells from the same batch cultured on the regular Col/HA scaffolds. In addition, MSCs cultured on the ECM-Col/HA scaffolds retained their "stemness" and osteogenic differentiation capacity better than MSCs cultured on regular Col/HA scaffolds. When ECM-Col/HA scaffolds were implanted into immunocompromised mice, with or without loading MSCs, it was found that those scaffolds formed less bone as compared with regular Col/HA scaffolds (i.e., without ECM), in both cases of with or without loading MSCs. The in vivo study further confirmed that the ECM-Col/HA scaffold was a suitable mimic of the bone marrow "niche." This novel 3D stromal-cell-derived ECM system has the potential to be developed into a biomedical platform for regenerative medicine applications.
迄今为止，骨髓间充质干细胞（MSCs）的扩增通常在二维（2D）组织培养塑料上进行。由于这种二维基质与生理情况有很大不同，MSCs在扩增过程中会逐渐丧失其独特的多能特性。最近，细胞外基质（ECM）微环境（“生态位”）在体内促进和调节干细胞行为方面的作用已得到阐明。因此，研究人员已将努力方向转向开发能够像天然组织ECM一样发挥作用的三维（3D）支架。在本研究中，我们证明在胶原/羟基磷灰石（Col/HA）支架内形成的基质细胞衍生的ECM，可模拟骨髓“生态位”，促进MSCs增殖并保留其分化能力。ECM由MSCs合成，以在体外重建组织特异性的3D微环境。在将ECM沉积到Col/HA支架内后，将构建体进行脱细胞处理，然后重新接种MSCs以研究其行为。数据表明，在ECM-Col/HA支架上培养的MSCs比在常规Col/HA支架上培养的同批次细胞生长明显更快。此外，与在常规Col/HA支架上培养的MSCs相比，在ECM-Col/HA支架上培养的MSCs能更好地保留其“干性”和成骨分化能力。当将ECM-Col/HA支架植入免疫缺陷小鼠体内时，无论是否负载MSCs，都发现与常规Col/HA支架（即没有ECM）相比，这些支架形成的骨较少。体内研究进一步证实ECM-Col/HA支架是骨髓“生态位”的合适模拟物。这种新型的3D基质细胞衍生的ECM系统有潜力被开发成用于再生医学应用的生物医学平台。
