Temporal expression patterns and corresponding protein inductions of early responsive genes in rabbit bone marrow-derived mesenchymal stem cells under cyclic compressive loading
Temporal expression patterns and corresponding protein inductions of early responsive genes in rabbit bone marrow-derived mesenchymal stem cells under cyclic compressive loading
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DOI：
10.1634/stemcells.2004-0202
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发表时间：
2005-09-01
期刊：
影响因子：
5.2
通讯作者：
Cheung, HS
中科院分区：
文献类型：
--
作者：
Huang, CYC;Reuben, PM;Cheung, HS
我们最近的研究表明，周期性压缩负荷可能通过转化生长因子（TGF）-β信号通路促进琼脂糖培养的兔骨髓间充质干细胞（BM-MSCs）的软骨形成。已经显示活化蛋白1（AP-1）（Jun-Fos）复合物介导TGF-β 1的自身诱导及其结合活性对于促进间充质细胞的软骨形成是必需的，而Sox 9被鉴定为胚胎间充质细胞的软骨形成的必需转录因子。本研究的目的是研究早期反应基因（Sox 9，c-Fos，c-Jun，TGF-β I型和II型受体）的时间表达模式和诱导其相应的蛋白质在琼脂糖培养的兔BM-MSCs进行循环压缩负荷。兔BM-MSCs从新西兰白色兔的胫骨和股骨获得。通过将BM-MSC悬浮在2%琼脂糖凝胶（10（7）个细胞/ml）中制备细胞-琼脂糖构建体，用于在定制的生物反应器中进行的循环无限制压缩测试。在加载实验中，使样本经受正弦加载，其幅度为15%应变，频率为1赫兹，每天4小时。实验连续进行2天。这项研究表明，循环压缩负荷促进了Sox 9，c-Jun和TGF-β受体的基因表达及其相应蛋白质的产生，而这些基因表达在基因之间和测试的2天之间表现出不同的时间表达模式。c-Fos基因的表达仅在动态压缩载荷1小时的样品中检测到。这些结果表明，TGF-β信号转导和AP-1和Sox 9的活性参与了动态压缩负荷促进的BM-MSC软骨形成的早期阶段。
Our recent study suggested that cyclic compressive loading may promote chondrogenesis of rabbit bone-marrow mesenchymal stem cells (BM-MSCs) in agarose cultures through the transforming growth factor (TGF)-beta signaling pathway. It has been shown that the activating protein 1 (AP-1) (Jun-Fos) complex mediated autoinduction of TGF-beta 1 and its binding activity was essential for promoting chondrogenesis of mesenchymal cells, whereas Sox9 was identified as an essential transcription factor for chondrogenesis of embryonic mesenchymal cells. The objective of this study was to examine temporal expression patterns of early responsive genes (Sox9, c-Fos, c-Jun, and TGF-beta type I and II receptors) and induction of their corresponding proteins in agarose culture of rabbit BM-MSCs subjected to cyclic compressive loading. The rabbit BM-MSCs were obtained from the tibias and femurs of New Zealand White rabbits. Cell-agarose constructs were made by suspending BM-MSCs in 2% agarose gel (10(7) cells/ml) for cyclic, unconfined compression tests performed in a custom-made bioreactor. In the loading experiment, specimens were subjected to sinusoidal loading with a magnitude of 15% strain at a frequency of I hertz for 4 hours per day. Experiments were conducted for 2 consecutive days. This study showed that cyclic compressive loading promoted gene expressions of Sox9, c-Jun, and both TGF-beta receptors and productions of their corresponding proteins, whereas those gene expressions exhibited different temporal expression patterns among genes and between 2 days of testing. The gene expression of c-Fos was detected only in the samples subjected to 1-hour dynamic compressive loading. These findings suggest that the TGF-beta signal transduction and activities of AP-1 and Sox9 are involved in the early stage of BM-MSC chondrogenesis promoted by dynamic compressive loading.