Fibroblast growth factor-2 and remodeled type I collagen control membrane protrusion in human vascular smooth muscle cells - Biphasic activation of Rac1
Fibroblast growth factor-2 and remodeled type I collagen control membrane protrusion in human vascular smooth muscle cells - Biphasic activation of Rac1
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DOI：
10.1074/jbc.m400711200
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发表时间：
2004-08-20
影响因子：
4.8
通讯作者：
Pickering, JG
中科院分区：
文献类型：
--
作者：
Fera, E;O'Neil, C;Pickering, JG
质膜突起是细胞运动的基础，但其受细胞外环境的调节还没有得到很好的阐明。我们已经量化了人血管平滑肌细胞暴露于成纤维细胞生长因子2（FGF-2）和I型胶原，两个不同的配体在动脉重塑过程中血管细胞的板状伪足突起动力学。视频显微镜检查显示，FGF-2刺激适度增加，在15分钟内达到峰值的片状lipodial突出率。这种反应与Rac 1的立即但短暂的激活，并在细胞感染逆转录病毒含有编码显性负Rac 1的cDNA被抑制。暴露于FGF-2 1小时也在24-36小时建立了更明显的板状伪足突出的第二阶段。这种延迟的反应是最明显的，当细胞在1型胶原蛋白，并与FGF-2诱导的胶原酶-1的表达，定位于突出的板状伪足的边缘。此外，晚期膜突起被抑制时，细胞对胶原酶耐药的I型胶原，牵连降解的胶原蛋白作为介质。对于胶原蛋白上的细胞，FGF-2对Rac 1的立即激活之后是Rac 1激活的持续波，当胶原蛋白三螺旋的切割被阻止时，Rac 1激活的持续波也被α（v）β（3）整联蛋白的阻断所抑制。我们的结论是，在平滑肌细胞中的lamellipodial突起可以调节波的Rac 1激活，相应的FGF-2和重塑胶原蛋白的顺序介绍。因此，这些发现揭示了细胞外输入之间先前未被认识到的协调水平，使细胞能够在长时间内保持兴奋性活动。
Plasma membrane protrusion is fundamental to cell motility, but its regulation by the extracellular environment is not well elucidated. We have quantified lamellipodial protrusion dynamics in human vascular smooth muscle cells exposed to fibroblast growth factor 2 (FGF-2) and type I collagen, two distinct ligands presented to vascular cells during arterial remodeling. Video microscopy revealed that FGF-2 stimulated a modest increase in lamellipodial protrusion rate that peaked within 15 min. This response was associated with immediate but transient activation of Rac1 and was inhibited in cells infected with retrovirus containing cDNA encoding dominant-negative Rac1. A 1-h exposure to FGF-2 also set up a second phase of more striking lamellipodial protrusion evident at 24-36 h. This delayed response was most pronounced when cells were on type 1 collagen and was associated with FGF-2-induced expression of collagenase-1 that localized to the edge of protruding lamellipodia. Moreover, late membrane protrusion was inhibited when cells were on collagenase-resistant type I collagen, implicating degraded collagen as a mediator. For cells on collagen, the immediate activation of Rac1 by FGF-2 was followed by a sustained wave of Rac1 activation that was inhibited when cleavage of the collagen triple helix was prevented and also by blockade of alpha(v)beta(3) integrin. We conclude that lamellipodial protrusion in smooth muscle cells can be regulated by waves of Rac1 activation, corresponding to the sequential presentation of FGF-2 and remodeled collagen. The findings thus reveal a previously unrecognized level of coordination among extracellular input that enables cells to maintain protrusive activity over prolonged periods.