Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213-3890, USA.
ACS Nano. 2010 Aug 24;4(8):4872-8. doi: 10.1021/nn101151x.
The ability of globular actin to form filaments and higher-order network structures of the cytoskeleton is essential for cells to maintain their shape and perform essential functions such as force generation, motility, and division. Alterations of actin structures can dramatically change a cell's ability to function. We found that purified and dispersed single wall carbon nanotubes (SWCNTs) can induce actin bundling in cells and in purified model actin systems. SWCNTs do not induce acute cell death, but cell proliferation is greatly reduced in SWCNT-treated cells with an increase in actin-related division defects. Actin, normally present in basal stress fibers in control cells, is located in heterogeneous structures throughout the SWCNT-treated cell. These SWCNT-induced changes in actin structures are seen functionally in multinucleated cells and with reduced force generation. Ex vivo, purified actin filaments cross-linked with alpha-actinin and formed isotropic networks, whereas SWCNTs caused purified actin filaments to assemble into bundles. While purified, isolated SWCNTs do not appear acutely toxic, this subcellular reorganization may cause chronic changes to cellular functions.
球状肌动蛋白形成纤维和细胞骨架的更高阶网络结构的能力对于细胞维持其形状和执行基本功能（如产生力、运动和分裂）至关重要。肌动蛋白结构的改变会极大地改变细胞的功能能力。我们发现，纯化和分散的单壁碳纳米管（SWCNT）可以诱导细胞内和纯化的模型肌动蛋白系统中的肌动蛋白束集。SWCNT 不会诱导急性细胞死亡，但 SWCNT 处理的细胞中的细胞增殖大大减少，同时出现与肌动蛋白相关的分裂缺陷增加。在对照细胞中，正常存在于基底应激纤维中的肌动蛋白，位于 SWCNT 处理细胞中的异质结构中。这些 SWCNT 诱导的肌动蛋白结构变化在多核细胞中以及力产生减少的情况下具有功能意义。在体外，用 α-辅肌动蛋白交联的纯化肌动蛋白丝形成各向同性网络，而 SWCNT 导致纯化的肌动蛋白丝组装成束。虽然纯化的、分离的 SWCNT 似乎没有急性毒性，但这种亚细胞重排可能会导致细胞功能的慢性变化。
