Actin stress fiber pre-extension in human aortic endothelial cells
Actin stress fiber pre-extension in human aortic endothelial cells
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DOI：
10.1002/cm.20260
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发表时间：
2008-04-01
影响因子：
--
通讯作者：
Yin, Frank C-P
中科院分区：
文献类型：
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作者：
Lu, Lan;Feng, Yunfeng;Yin, Frank C-P
肌动蛋白应力纤维（Actin stress fibers，SFs）使细胞能够感知和响应机械刺激，并影响粘附、运动和凋亡。我们和其他人已经证明，培养的人主动脉内皮细胞（HAECs）的内部强调，使SF是预先延长超过其卸载长度。本研究探讨了影响SF预扩展的因素。在过夜培养的HAEC中，基线预延伸为1.10，并且与细胞缩短的量无关。用30 mM BDM或10 μ M blebbistatin降低收缩性使预延伸降低至1.05，而用2 nM calyculin A增加收缩性使预延伸增加至1.26。敲低α-辅肌动蛋白-1与干扰RNA增加预延伸至1.28。这些都不影响屈曲SF的波长。在未受干扰的细胞中，预延伸与那些肌动蛋白细胞骨架被化学和机械手段破坏，然后重新组装的细胞相同。最后，破坏MT或IF不影响预延伸，但增加了波长。两者合计，这些结果表明，SF的预延伸主要是由内在因素，即肌动蛋白-肌球蛋白相互作用的水平决定的。这种对预延伸的内在控制是足够强大的，即使在肌动蛋白细胞骨架被破坏和重组之后，预延伸也是相同的。与预延伸不同，压缩SF的形态部分地由MT和IF决定，MT和IF似乎沿着SF的长度沿着支撑SF。
Actin stress fibers (SFs) enable cells to sense and respond to mechanical stimuli and affect adhesion, motility and apoptosis. We and others have demonstrated that cultured human aortic endothelial cells (HAECs) are internally stressed so that SFs are pre-extended beyond their unloaded lengths. The present study explores factors affecting SF pre-extension. In HAECs cultured overnight the baseline pre-extension was 1.10 and independent of the amount of cell shortening. Decreasing contractility with 30 mM BDM or 10 mu M blebbistatin decreased pre-extension to 1.05 whereas increasing contractility with 2 nM calyculin A increased pre-extension to 1.26. Knockdown of alpha-actinin-1 with an interfering RNA increased pre-extension to 1.28. None of these affected the wavelength of the buckled SFs. Pre-extension was the same in unperturbed cells as in those in which the actin cytoskeleton was disrupted by both chemical and mechanical means and then allowed to reassemble. Finally, disrupting MTs or IFs did not affect pre-extension but increased the wavelength. Taken together, these results suggest that pre-extension of SFs is determined primarily by intrinsic factors, i.e. the level of actin-myosin interaction. This intrinsic control of pre-extension is sufficiently robust that pre-extension is the same even after the actin cytoskeleton has been disrupted and reorganized. Unlike pre-extension, the morphology of the compressed SFs is partially determined by MTs and IFs which appear to support the SFs along their lengths.