Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA.
Sci Rep. 2012;2:455. doi: 10.1038/srep00455. Epub 2012 Jun 13.
Directed specification and prospective isolation of chondrogenic paraxial mesoderm progeny from human pluripotent stem (PS) cells have not yet been achieved. Here we report the successful generation of KDR(-)PDGFRα(+) progeny expressing paraxial mesoderm genes and the mesendoderm reporter MIXL1-GFP in a chemically defined medium containing the canonical WNT signaling activator, BMP-inhibitor, and the Nodal/Activin/TGFβ signaling controller. Isolated (GFP(+))KDR(-)PDGFRα(+) mesoderm cells were sensitive to sequential addition of the three chondrogenic factors PDGF, TGFβ and BMP. Under these conditions, the cells showed robust chondrogenic activity in micromass culture, and generated a hyaline-like translucent cartilage particle in serum-free medium. In contrast, both STRO1(+) mesenchymal stem/stromal cells from adult human marrow and mesenchymal cells spontaneously arising from hPS cells showed a relatively weaker chondrogenic response in vitro, and formed more of the fibrotic cartilage particles. Thus, hPS cell-derived KDR(-)PDGFRα(+ )paraxial mesoderm-like cells have potential in engineered cartilage formation and cartilage repair.
从人类多能干细胞（PS）中定向指定和前瞻性分离软骨形成轴旁中胚层祖细胞尚未实现。在这里，我们报告了在含有经典 WNT 信号激活剂、BMP 抑制剂和 Nodal/Activin/TGFβ 信号控制器的化学定义培养基中成功生成表达轴旁中胚层基因和中胚层-内胚层报告基因 MIXL1-GFP 的 KDR(-)PDGFRα(+)祖细胞。分离的（GFP(+)）KDR(-)PDGFRα(+)中胚层细胞对顺序添加三种软骨形成因子 PDGF、TGFβ 和 BMP 敏感。在这些条件下，细胞在微团培养中表现出强大的软骨生成活性，并在无血清培养基中生成透明样半透明软骨颗粒。相比之下，来自成人骨髓的 STRO1(+)间充质干细胞和 hPS 细胞自发产生的间充质细胞在体外的软骨生成反应相对较弱，并形成更多的纤维性软骨颗粒。因此，hPS 细胞衍生的 KDR(-)PDGFRα(+)轴旁中胚层样细胞在工程化软骨形成和软骨修复中具有潜力。
