Sox9 expression of alginate-encapsulated chondrocytes is stimulated by low cell density
Sox9 expression of alginate-encapsulated chondrocytes is stimulated by low cell density
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DOI：
10.1002/jbm.a.32308
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发表时间：
2009-12-01
影响因子：
4.9
通讯作者：
Fickert, Stefan
中科院分区：
文献类型：
--
作者：
Bernstein, Peter;Dong, Meng;Fickert, Stefan
用于治疗软骨缺陷的组织工程的最新研究表明，基质生物材料、细胞培养条件和细胞因子相关因素影响软骨形成分化模式，特别是基质基因的表达。然而，关于三维环境中细胞接种密度对关键软骨形成转录因子 Sox9 的影响知之甚少。在这里，我们研究了海藻酸盐封装软骨细胞的细胞浓度是否影响 Sox9 的表达。将去分化的第 4 代猪软骨细胞以两种不同浓度（4 X 10(6) 与 7 X 10(7) 细胞/mL）封装在藻酸盐珠中，并在 TGF-β 刺激下培养长达 4 周。通过定量 RT-PCR 评估 Sox9、胶原蛋白 I、II 和 X 的表达，并与初始单层培养物中观察到的表达进行比较。监测细胞活力、细胞形态和硫酸化糖胺聚糖的产生。有趣的是，Sox9 表达在低细胞密度组中显着上调，而高细胞密度组和单层培养组之间没有观察到差异。此外，低细胞密度组的细胞存活率和硫酸化糖胺聚糖产量较高。低细胞密度组中 I 型胶原蛋白表达下调，而高细胞密度组中 I 型胶原蛋白表达上调。令人惊讶的是，只有高细胞密度组显示出 II 型胶原蛋白的表达，尽管看起来并不显着。低细胞密度组中 X 胶原蛋白表达上调。综上所述，我们的数据表明，三维环境中低浓度的细胞接种有利于整体软骨发育。然而，本文揭示了 Sox9 与软骨细胞再分化中的软骨形成途径之间的差异，应在进一步的工作中解决。 (C) 2008 Wiley periodicals, Inc. J Biomed Mater Res 91A: 910-918, 2009
Recent research in tissue engineering for the treatment of cartilage defects have demonstrated that matrix-biomaterial, cell culture conditions, and cytokine-related factors influence the chondrogenic differentiation pattern, especially for the expression of matrix genes. However, little is known about the impact of cell seeding density in a three-dimensional environment on the key chondrogenic transcription factor Sox9. Here we investigated, whether the cell concentration of alginate encapsulated chondrocytes influences the Sox9 expression. Dedifferentiated passage-4 porcine chondrocytes were encapsulated in alginate beads at two different concentrations (4 X 10(6) versus 7 X 10(7) cells/mL) and cultivated for up to 4 weeks under TGF-beta Stimulation. The expression of Sox9, Collagen I, II, and X was assessed via quantitative RT-PCR and compared to those observed in the initial monolayer culture. Cellular viability, cell morphology, and the sulphated glycosaminoglycan-production were monitored. Interestingly Sox9 expression was significantly upregulated in the low-cell-density group, whereas no difference between high-cell-density and monolayer culture group could be observed. Furthermore, the cellular survival and the sulphated glycosaminoglycan production were higher in the low-cell-density group. Collagen I expression was downregulated in the low-cell-density group whereas it was upregulated in the high-cell-density one. Surprisingly, only the high-cell-density group showed the expression of Collagen II, although it appeared not significant. Collagen X expression was upregulated in the low-cell-density group. Taken together our data indicate that a low concentration of cell seeding in a three-dimensional environment is beneficial for the overall chondrogenic development. However, this article reveals discrepancies between Sox9 and the chondrogenic pathway in redifferentiating chondrocytes that should be addressed in further work. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 91A: 910-918, 2009