Cytoskeletal organization of human mesenchymal stem cells (MSC) changes during their osteogenic differentiation
Cytoskeletal organization of human mesenchymal stem cells (MSC) changes during their osteogenic differentiation
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DOI：
10.1002/jcb.20234
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发表时间：
2004-11-01
影响因子：
4
通讯作者：
Cambiazo, V
中科院分区：
文献类型：
--
作者：
Rodríguez, JP;González, M;Cambiazo, V
人类间充质干细胞已被研究，以确定参与正常骨重塑和成骨调节的机制。在成骨分化过程中，间充质干细胞从其典型的成纤维细胞样表型转变为接近球形。在本研究中，我们分析了MSCs的细胞骨架组织、细胞形态变化与成骨分化特异性标志物（碱性磷酸酶活性和钙沉积）表达的相关性。为了成骨细胞分化，将细胞培养在添加了100 mM地塞米松、10 mM β -甘油磷酸酯和50马克杯/毫升抗坏血酸的培养基中。用Alexa flu594 phalloidin和抗α -微管蛋白单克隆抗体免疫荧光检测微丝和微管的组织。细胞松弛素D和诺可唑可可逆地改变细胞骨架动力学。在成骨分化过程中，观察到人间充质干细胞的细胞骨架组织发生了显著变化。在未分化的间充质干细胞中，肌动蛋白细胞骨架由大量的细的、平行的微丝束延伸到整个细胞质中，而在分化的细胞中，肌动蛋白细胞骨架由位于最外周的几个粗的肌动蛋白丝束改变。在成骨培养条件下，细胞松弛素D （cytochalasin D）而非诺可达唑（nocodazole）初始处理诱导的微丝可逆重组降低了分化标志物的表达，但不影响细胞的最终形态。结果表明，微丝的组装和拆卸动力学的变化以及肌动蛋白网络形成的动态可能是支持人间充质干细胞成骨分化的关键；还表明，微管的组织似乎对这一过程的动力学具有调节作用。(C) 2004 Wiley-Liss, Inc。
Human MSCs have been studied to define the mechanisms involved in normal bone remodeling and the regulation of osteogenesis. During osteogenic differentiation, MSCs change from their characteristic fibroblast-like phenotype to near spherical shape. In this study, we analyzed the correlation between the organization of cytoskeleton of MSCs, changes in cell morphology, and the expression of specific markers (alkaline phosphatase activity and calcium deposition) of osteogenic differentiation. For osteoblastic differentiation, cells were cultured in a culture medium supplemented with 100 mM dexamethasone, 10 mM beta-glycerophosphate, and 50 mug/ml ascorbic acid. The organization of microfilaments and microtubules was examined by inmunofluorescence using Alexa fluor 594 phalloidin and anti alpha-tubulin monoclonal antibody. Cytochalasin D and nocodazole were used to alter reversibly the cytoskeleton dynamic. A remarkable change in cytoskeleton organization was observed in human MSCs during osteogenic differentiation. Actin cytoskeleton changed from a large number of thin, parallel microfilament bundles extending across the entire cytoplasm in undifferentiated MSCs to a few thick actin filament bundles located at the outermost periphery in differentiated cells. Under osteogenic culture conditions, a reversible reorganization of microfilaments induced by an initial treatment with cytochalasin D but not with nocodazole reduced the expression of differentiation markers, without affecting the final morphology of the cells. The results indicate that changes in the assembly and disassembly kinetics of microfilaments dynamic of actin network formation may be critical in supporting the osteogenic differentiation of human MSCs; also indicated that the organization of microtubules appears to have a regulatory role on the kinetic of this process. (C) 2004 Wiley-Liss, Inc.