Department of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
Division of Rheumatology, Brigham and Women's Hospital, Boston, MA 02115, USA.
Development. 2015 Feb 1;142(3):438-43. doi: 10.1242/dev.113571. Epub 2015 Jan 6.
Cell-based bone regeneration strategies offer promise for traumatic bone injuries, congenital defects, non-union fractures and other skeletal pathologies. Postnatal bone remodeling and fracture healing provide evidence that an osteochondroprogenitor cell is present in adult life that can differentiate to remodel or repair the fractured bone. However, cell-based skeletal repair in the clinic is still in its infancy, mostly due to poor characterization of progenitor cells and lack of knowledge about their in vivo behavior. Here, we took a combined approach of high-throughput screening, flow-based cell sorting and in vivo transplantation to isolate markers that identify osteochondroprogenitor cells. We show that the presence of tetraspanin CD9 enriches for osteochondroprogenitors within CD105(+) mesenchymal cells and that these cells readily form bone upon transplantation. In addition, we have used Thy1.2 and the ectonucleotidase CD73 to identify subsets within the CD9(+) population that lead to endochondral or intramembranous-like bone formation. Utilization of this unique cell surface phenotype to enrich for osteochondroprogenitor cells will allow for further characterization of the molecular mechanisms that regulate their osteogenic properties.
基于细胞的骨再生策略为外伤性骨损伤、先天性缺陷、骨不连骨折和其他骨骼病理学提供了希望。成体骨重塑和骨折愈合的证据表明，在成年生活中有一个骨软骨祖细胞存在，它可以分化为重塑或修复骨折的骨。然而，基于细胞的骨骼修复在临床上仍处于起步阶段，主要是由于对祖细胞的特征描述不佳，以及对其体内行为的了解不足。在这里，我们采用了高通量筛选、基于流式细胞术的细胞分选和体内移植相结合的方法，来分离鉴定骨软骨祖细胞的标志物。我们表明，四跨膜蛋白 CD9 的存在丰富了 CD105(+)间充质细胞中的骨软骨祖细胞，并且这些细胞在移植后很容易形成骨。此外，我们还利用 Thy1.2 和外核苷酸酶 CD73 来鉴定 CD9(+)群体中的亚群，这些亚群导致软骨内或膜内样骨形成。利用这种独特的细胞表面表型来富集骨软骨祖细胞，将有助于进一步阐明调节其成骨特性的分子机制。
