Changes in the intra- and extra-mechanical environment of the nucleus in Saos-2 osteoblastic cells during bone differentiation process: Nuclear shrinkage and stiffening in cell differentiation
Changes in the intra- and extra-mechanical environment of the nucleus in Saos-2 osteoblastic cells during bone differentiation process: Nuclear shrinkage and stiffening in cell differentiation
复制标题
Saos-2成骨细胞在骨分化过程中细胞核内外机械环境的变化：细胞分化过程中的核收缩和硬化
DOI：
10.1016/j.jmbbm.2022.105630
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发表时间：
2023
影响因子：
3.9
通讯作者：
Matsumoto Takeo
中科院分区：
文献类型：
--
作者：
Nagayama Kazuaki;Kodama Fumiki;Wataya Naoki;Sato Akiko;Matsumoto Takeo
据报道，成骨分化受到各种机械应力的调节，包括流体剪切应力以及拉伸和压缩载荷。通过这些机械应力促进成骨细胞分化伴随着F-肌动蛋白细胞骨架的重组，这与细胞内力和机械环境密切相关。然而，有有限的信息对细胞内细胞核的机械环境的影响，如细胞核的机械性能和细胞内施加在细胞核上的力，最近被发现直接参与各种细胞功能。在这里，我们研究了细胞内的变化力施加到细胞核和核形态和力学性能的影响，在人成骨细胞样细胞（Saos-2）成骨分化。我们用共聚焦荧光显微镜进行了细胞形态学分析，用原子力显微镜（AFM）进行了核压痕试验，并对核内DNA进行了光漂白后的荧光恢复（FRAP）。结果表明，一个显着的重组的F-肌动蛋白细胞骨架从核表面的细胞周围发生在成骨分化过程中，同时减少压力的核。这种变化也促进核收缩和硬化，并进一步核内染色质致密化。结果表明，由于F-actin细胞骨架的重组而导致的细胞内压力的降低影响了细胞核的内部和外部机械环境，并且这种变化可能影响成骨分化过程中的基因表达和DNA复制。
Osteogenic differentiation has been reportedly regulated by various mechanical stresses, including fluid shear stress and tensile and compressive loading. The promotion of osteoblastic differentiation by these mechanical stresses is accompanied by reorganization of the F-actin cytoskeleton, which is deeply involved in intracellular forces and the mechanical environment. However, there is limited information about the effect on the mechanical environment of the intracellular nucleus, such as the mechanical properties of the nucleus and intracellular forces exerted on the nucleus, which have recently been found to be directly involved in various cellular functions. Here, we investigated the changes in the intracellular force applied to the nucleus and the effect on nuclear morphology and mechanical properties during osteogenic differentiation in human osteoblast-like cells (Saos-2). We carried out cell morphological analyses with confocal fluorescence microscopy, nuclear indentation test with atomic force microscopy (AFM), and fluorescence recovery after photobleaching (FRAP) for intranuclear DNA. The results revealed that a significant reorganization of the F-actin cytoskeleton from the nuclear surfaces to the cell periphery occurred in the osteogenic differentiation processes, simultaneously with the reduction of compressive forces to the nucleus. Such changes also facilitated nuclear shrinkage and stiffening, and further intranuclear chromatin compaction. The results indicate that the reduction of the intracellular compressive force due to reorganization of the F-actin cytoskeleton affects the intra- and extra-mechanical environment of the nucleus, and this change may affect gene expression and DNA replication in the osteogenic differentiation process.