Alenghat Francis J, Nauli Surya M, Kolb Robert, Zhou Jing, Ingber Donald E
Vascular Biology Program, Departments of Pathology and Surgery, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Exp Cell Res. 2004 Nov 15;301(1):23-30. doi: 10.1016/j.yexcr.2004.08.003.
Studies of mechanotransduction mediated by stress-sensitive ion channels generally focus on the site of force application to the cell. Here we show that global, cell-wide changes in cytoskeletal structure and mechanics can regulate mechanotransduction previously shown to be triggered by activation of the mechanosensitive calcium channel, polycystin-2, in the apical primary cilium of renal epithelial cells [S.M. Nauli, F.J. Alenghat, Y. Luo, E. Williams, P. Vassilev, X. Li, A.E. Elia, W. Lu, E.M. Brown, S.J. Quinn, D.E. Ingber, J. Zhou, Polycystins 1 and 2 mediate mechanosensation in the primary cilium of kidney cells. Nat. Genet. 33 (2003) 129-37]. Disrupting cytoplasmic microfilaments or microtubules in these cells eliminated fluid shear stress-induced increase of intracellular calcium. Altering the cytoskeletal force balance by inhibiting actomyosin-based tension generation (using 2,3-butanedione monoxime), interfering with microtubule polymerization (using nocodazole, cochicine, or taxol), or disrupting basal integrin-dependent extracellular matrix adhesions (using soluble GRGDSP peptide or anti-beta1 integrin antibody), also inhibited the calcium spike in response to fluid stress. These data indicate that although fluid stress-induced displacement of the primary cilium may be transduced into a calcium spike through activation of polycystin-2 and associated calcium-induced calcium release from intracellular stores, this mechanotransduction response is governed by global mechanical cues, including isometric tension (prestress) within the entire cytoskeleton and intact adhesions to extracellular matrix.
由应力敏感离子通道介导的机械转导研究通常聚焦于作用于细胞的力的施加部位。在此我们表明，细胞骨架结构和力学的全局性、全细胞范围的变化可调节先前显示由机械敏感钙通道多囊蛋白-2在肾上皮细胞顶端初级纤毛中的激活所触发的机械转导[S.M. 瑙利、F.J. 阿连加特、Y. 罗、E. 威廉姆斯、P. 瓦西列夫、X. 李、A.E. 埃利亚、W. 卢、E.M. 布朗、S.J. 奎因、D.E. 英格伯、J. 周，多囊蛋白1和2介导肾细胞初级纤毛中的机械感觉。《自然遗传学》33卷（2003年）129 - 37页]。破坏这些细胞中的细胞质微丝或微管消除了流体剪切应力诱导的细胞内钙增加。通过抑制基于肌动球蛋白的张力产生（使用2,3 - 丁二酮单肟）、干扰微管聚合（使用诺考达唑、秋水仙碱或紫杉醇）或破坏基础整合素依赖性细胞外基质黏附（使用可溶性GRGDSP肽或抗β1整合素抗体）来改变细胞骨架力平衡，也抑制了对流体应力的钙峰值反应。这些数据表明，尽管流体应力诱导的初级纤毛位移可能通过多囊蛋白-2的激活以及相关的细胞内钙库钙诱导钙释放转导为钙峰值，但这种机械转导反应受全局性机械信号调控，包括整个细胞骨架内的等长张力（预应力）和与细胞外基质的完整黏附。
