Extracellular matrix controls myosin light chain phosphorylation and cell contractility through modulation of cell shape and cytoskeletal prestress
Extracellular matrix controls myosin light chain phosphorylation and cell contractility through modulation of cell shape and cytoskeletal prestress
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DOI：
10.1152/ajpcell.00280.2003
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发表时间：
2004-03-01
影响因子：
5.5
通讯作者：
Ingber, DE
中科院分区：
文献类型：
--
作者：
Polte, TR;Eichler, GS;Ingber, DE
血管平滑肌（VSM）细胞响应细胞外基质的结构信号调节其收缩性的机制仍知之甚少。当肺 VSM 细胞在固定化纤连蛋白 (FN) 密度不断增加的情况下培养时，细胞铺展、肌球蛋白轻链 (MLC) 磷酸化、细胞骨架预应力（血管激动剂刺激前细胞内的等长张力）以及对血管收缩剂内皮素 1 的主动收缩反应均同时增加。相反，当悬浮细胞与 FN 包被的微珠（直径 4.5 微米）结合或在微米大小（30 X 30 微米）的 FN 岛上培养时，MLC 磷酸化不会增加，该岛周围有支持整合素结合但阻止细胞扩散的非粘附区域。当柔性 FN 基质的机械顺应性提高时，细胞铺展和 MLC 磷酸化也同时降低。当在完全扩散的细胞中使用肌球蛋白 ATP 酶抑制剂消除细胞骨架预应力时，MLC 磷酸化受到独立于细胞形状的抑制，而当使用诺考达唑破坏粘附于 FN 的细胞中的微管时，MLC 磷酸化增加至最大水平，但在悬浮细胞中则不然。这些数据表明，细胞外基质（ECM）相互作用的变化在生化信号转导水平上调节平滑肌细胞的收缩性，并表明这种调节的机制可能涉及ECM和细胞骨架之间的物理相互作用，使得细胞铺展和细胞骨架张力的产生反馈以促进MLC磷酸化并进一步增加张力的产生。
The mechanism by which vascular smooth muscle (VSM) cells modulate their contractility in response to structural cues from extracellular matrix remains poorly understood. When pulmonary VSM cells were cultured on increasing densities of immobilized fibronectin (FN), cell spreading, myosin light chain (MLC) phosphorylation, cytoskeletal prestress (isometric tension in the cell before vasoagonist stimulation), and the active contractile response to the vasoconstrictor endothelin-1 all increased in parallel. In contrast, MLC phosphorylation did not increase when suspended cells were allowed to bind FN-coated microbeads (4.5-mum diameter) or cultured on micrometer- sized (30 X 30 mum) FN islands surrounded by nonadhesive regions that support integrin binding but prevent cell spreading. Cell spreading and MLC phosphorylation also both decreased in parallel when the mechanical compliance of flexible FN substrates was raised. MLC phosphorylation was inhibited independently of cell shape when cytoskeletal prestress was dissipated using a myosin ATPase inhibitor in fully spread cells, whereas it increased to maximal levels when microtubules were disrupted using nocodazole in cells adherent to FN but not in suspended cells. These data demonstrate that changes in cellextracellular matrix (ECM) interactions modulate smooth muscle cell contractility at the level of biochemical signal transduction and suggest that the mechanism underlying this regulation may involve physical interplay between ECM and the cytoskeleton, such that cell spreading and generation of cytoskeletal tension feed back to promote MLC phosphorylation and further increase tension generation.