Kim Hyunju, Kim Ilsoo, Choi Heon-Jin, Kim So Yeon, Yang Eun Gyeong
Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, South Korea.
Nanoscale. 2015 Oct 28;7(40):17131-8. doi: 10.1039/c5nr05787f.
The behavior of mammalian cells on vertical nanowire (NW) arrays, including cell spreading and the dynamic distribution of focal adhesions and cytoskeletal proteins, has been intensively studied to extend the implications for cellular manipulations in vitro. Prompted by the result that cells on silicon (Si) NWs showed morphological changes and reduced migration rates, we have explored the transition of mesenchymal stem cells into a neuronal lineage by using SiNWs with varying lengths. When human mesenchymal stem cells (hMSCs) were cultured on the longest SiNWs for 3 days, most of the cells exhibited elongated shapes with neurite-like extensions and dot-like focal adhesions that were prominently observed along with actin filaments. Under these circumstances, the cell motility analyzed by live cell imaging was found to decrease due to the presence of SiNWs. In addition, the slowed growth rate, as well as the reduced population of S phase cells, suggested that the cell cycle was likely arrested in response to the differentiation process. Furthermore, we measured the mRNA levels of several lineage-specific markers to confirm that the SiNWs actually induced neuron-like differentiation of the hMSCs while hampering their osteogenic differentiation. Taken together, our results implied that SiNWs were capable of inducing active reorganization of cellular behaviors, collectively guiding the fate of hMSCs into the neural lineage even in the absence of any inducing reagent.
为了拓展体外细胞操作的意义，人们对哺乳动物细胞在垂直纳米线（NW）阵列上的行为进行了深入研究，包括细胞铺展以及粘着斑和细胞骨架蛋白的动态分布。鉴于硅（Si）纳米线上的细胞呈现形态变化且迁移速率降低这一结果，我们利用不同长度的硅纳米线探索了间充质干细胞向神经谱系的转变。当人类间充质干细胞（hMSCs）在最长的硅纳米线上培养3天时，大多数细胞呈现出伸长的形状，并带有神经突样延伸以及点状粘着斑，这些粘着斑与肌动蛋白丝一起显著可见。在这种情况下，通过活细胞成像分析发现，由于硅纳米线的存在，细胞运动性降低。此外，生长速率减慢以及S期细胞数量减少，表明细胞周期可能因分化过程而停滞。此外，我们测量了几种谱系特异性标志物的mRNA水平，以确认硅纳米线实际上诱导了hMSCs的神经元样分化，同时抑制了它们的成骨分化。综上所述，我们的结果表明，即使在没有任何诱导试剂的情况下，硅纳米线也能够诱导细胞行为的积极重组，共同引导hMSCs的命运走向神经谱系。
