Institute of Technical Chemistry, Leibniz University Hanover, Callinstrasse 5, 30167, Hannover, Germany.
Cell Tissue Res. 2013 Jul;353(1):117-22. doi: 10.1007/s00441-013-1597-7. Epub 2013 Apr 12.
Efficient cell expansion is a basic requirement for obtaining clinically relevant numbers of mesenchymal stem cells designed for cell-based therapies or tissue-engineering application. Previous studies have demonstrated that mesenchymal stem cells (MSC) cultivated under reduced atmospheric oxygen concentrations (2.5% O2) possess enhanced proliferation potential and can maintain their differentiation properties. We have analyzed the oxygen-dependent cytokine expression of human MSC derived from umbilical cord and attempted to link the results to the proliferation and differentiation capacities of these cells. By quantitative reverse transcription plus the polymerase chain reaction and by protein microarray, we measured the gene expression and intracellular protein concentration of several growth factors and growth factor receptors. Fibroblast growth factor-7, two growth factor receptors (vascular endothelial growth factor receptor 2 and stem cell factor receptor), and two growth-factor-binding proteins (insulin-like growth-factor-binding proteins 3 and 6) were over-expressed under hypoxic conditions, indicating that their signaling pathways participate in cell proliferation. On the other hand, typical differentiation factors such as bone morphogenetic protein-4, endothelial growth factor, and tissue growth factor-β1 were absent in cells cultivated under hypoxic and normoxic conditions. The absolute concentration of some intracellular cytokines was also measured for the first time under hypoxia and normoxia. Our results in combination with previous findings indicate that enhanced proliferation potential and a maintained undifferentiated cell state can be ascribed to the oxygen-dependent expression of a set of cytokines. This knowledge might help in the understanding of MSC physiology and in the achievement of directed cell fate of MSC for clinical application.
高效的细胞扩增是获得用于细胞治疗或组织工程应用的临床相关数量的间充质干细胞的基本要求。先前的研究表明，在低氧浓度（2.5%O2）下培养的间充质干细胞（MSC）具有增强的增殖潜力，并能保持其分化特性。我们分析了来源于脐带的人 MSC 的依赖氧细胞因子表达，并试图将结果与这些细胞的增殖和分化能力联系起来。通过定量逆转录聚合酶链反应和蛋白质微阵列，我们测量了几种生长因子和生长因子受体的基因表达和细胞内蛋白浓度。成纤维细胞生长因子-7、两种生长因子受体（血管内皮生长因子受体 2 和干细胞因子受体）和两种生长因子结合蛋白（胰岛素样生长因子结合蛋白 3 和 6）在低氧条件下过度表达，表明其信号通路参与细胞增殖。另一方面，典型的分化因子，如骨形态发生蛋白-4、内皮生长因子和组织生长因子-β1，在低氧和常氧条件下培养的细胞中不存在。细胞内一些细胞因子的绝对浓度也是首次在低氧和常氧条件下测量的。我们的研究结果与先前的研究结果相结合表明，增强的增殖潜力和未分化的细胞状态可以归因于一组细胞因子的氧依赖性表达。这些知识可能有助于理解 MSC 的生理学，并实现 MSC 的定向细胞命运用于临床应用。
