Laboratory for Molecular Endocrinology (KMEB), Department of Endocrinology, University Hospital of Odense and Medical Biotechnology Center, University of Southern Denmark, Odense C, Denmark.
J Bone Miner Res. 2010 Apr;25(4):796-808. doi: 10.1359/jbmr.091018.
The ability of bone marrow stromal cells (BMSCs) to differentiate into osteoblasts is being exploited in cell-based therapy for repair of bone defects. However, the phenotype of ex vivo cultured BMSCs predicting their bone-forming capacity is not known. Thus we employed DNA microarrays comparing two human bone marrow stromal cell (hBMSC) populations: One is capable of in vivo heterotopic bone formation (hBMSC-TERT(+Bone)), and the other is not (hBMSC-TERT(-Bone)). Compared with hBMSC-TERT(-Bone), the hBMSC-TERT(+Bone) cells had an increased overrepresentation of extracellular matrix genes (17% versus 5%) and a larger percentage of genes with predicted SP3 transcription factor-binding sites in their promoter region (21% versus 8%). On the other hand, hBMSC-TERT(-Bone) cells expressed a larger number of immune-response-related genes (26% versus 8%). In order to test for the predictive value of these markers, we studied the correlation between their expression levels in six different hBMSC-derived clones and the ability to form bone in vivo. We found a significant correlation for decorin, lysyl oxidase-like 4, natriuretic peptide receptor C, and tetranectin. No significant positive correlation was found for canonical osteoblastic markers Runx2, alkaline phosphatase, collagen type I, osteopontin, and bone sialoprotein. Prospective isolation of four additional hBMSC clones based on their expression levels of the molecular markers correlated with their in vivo bone-formation ability. In conclusion, our data suggest an in vitro molecular signature predictive for hBMSCs' in vivo bone-formation ability. Identifying more of these predictive markers would be very useful in the quality control of osteoblastic cells before use in therapy.
骨髓基质细胞（BMSCs）分化为成骨细胞的能力正被应用于基于细胞的治疗方法中，以修复骨缺损。然而，尚不清楚体外培养的 BMSCs 的表型是否能预测其成骨能力。因此，我们采用 DNA 微阵列比较了两种人骨髓基质细胞（hBMSC）群体：一种具有体内异位成骨能力（hBMSC-TERT(+Bone)），另一种则没有（hBMSC-TERT(-Bone)）。与 hBMSC-TERT(-Bone)相比，hBMSC-TERT(+Bone)细胞的细胞外基质基因表达增加（17%比 5%），且在其启动子区域具有预测的 SP3 转录因子结合位点的基因比例更大（21%比 8%）。另一方面，hBMSC-TERT(-Bone)细胞表达了更多的免疫反应相关基因（26%比 8%）。为了检验这些标记物的预测价值，我们研究了它们在六个不同的 hBMSC 衍生克隆中的表达水平与体内成骨能力之间的相关性。我们发现核心蛋白聚糖、赖氨酰氧化酶样 4、利钠肽受体 C 和四糖蛋白与成骨能力呈显著正相关。经典的成骨细胞标志物 runt 相关转录因子 2、碱性磷酸酶、胶原 I、骨桥蛋白和骨唾液蛋白则没有显著的正相关。根据这些分子标记物的表达水平，对另外四个 hBMSC 克隆进行前瞻性分离，与它们的体内成骨能力相关。总之，我们的数据表明，体外分子特征可预测 hBMSCs 的体内成骨能力。鉴定出更多的这些预测标记物，将在治疗前对成骨细胞进行质量控制时非常有用。
